S04.A Frequent Pattern Based Framework for Event Detection in Sensor Network Stream Data

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Finding Minimum Representative Pattern SetsGuimei Liu School of Computing National University ofSingapore liugm@.sgHaojun ZhangSchool of ComputingNational University ofSingaporezhanghao@.sgLimsoon WongSchool of ComputingNational University ofSingaporewongls@.sgABSTRACTFrequent pattern mining often produces an enormous num-ber of frequent patterns,which imposes a great challenge on understanding and further analysis of the generated pat-terns.This calls for the need ofﬁnding a small number of representative patterns to best approximate all other pat-terns.An ideal approach should1)produce a minimum number of representative patterns;2)can restore the sup-port of all patterns with error guarantee;and3)have good eﬃciency.Few existing approaches can satisfy all the three requirements.In this paper,we develop two algorithms, MinRPset and FlexRPset,forﬁnding minimum representa-tive pattern sets.Both algorithms provide error guarantee. MinRPset produces the smallest solution that we can pos-sibly have in practice under the given problem setting,and it takes a reasonable amount of time toﬁnish.FlexRPset is developed based on MinRPset.It provides one extra pa-rameter K to allow users to make a trade-oﬀbetween result size and eﬃciency.Our experiment results show that Min-RPset and FlexRPset produce fewer representative patterns than RPlocal—an eﬃcient algorithm that is developed for solving the same problem.FlexRPset can be slightly faster than RPlocal when K is small.Categories and Subject DescriptorsH.2.8[DATABASE MANAGEMENT]:Database Ap-plications—Data MiningKeywordsrepresentative patterns,frequent pattern summarization 1.INTRODUCTIONFrequent pattern mining is an important problem in the data mining area.It wasﬁrst introduced by Agrawal et al.in1993[4].Frequent pattern mining is usually per-formed on a transaction database D={t1,t2,...,t n},where t j is a transaction containing a set of items,j∈[1,n].Let I={i1,i2,...,i m}be the set of distinct items appearing in D.A pattern X is a set of items in I,that is,X⊆I.If a transaction t∈D contains all the items of a pattern X, then we say t supports X and t is a supporting transaction of X.Let T(X)be the set of transactions in D support-ing pattern X.The support of X,denoted as supp(X),is deﬁned as|T(X)|.If the support of a pattern X is larger than a user-speciﬁed threshold min sup,then X is called a frequent pattern.Given a transaction database D and a minimum support threshold min sup,the task of frequent pattern mining is toﬁnd all the frequent patterns in D with respect to min sup.Many eﬃcient algorithms have been developed for mining frequent patterns[9].Now the focus has shifted from how to eﬃciently mine frequent patterns to how to eﬀectively uti-lize them.Frequent patterns has the anti-monotone prop-erty:if a pattern is frequent,then all of its subsets must be frequent too.On dense datasets and/or when the minimum support is low,long patterns can be frequent.All the sub-sets of these frequent long patterns are frequent too based on the anti-monotone property.This leads to an explosion in the number of frequent patterns.The huge quantity of patterns can easily become a bottleneck for understanding and further analyzing frequent patterns.It has been observed that the complete set of frequent pat-terns often contains a lot of redundancy.Many frequent patterns have similar items and supporting transactions.It is desirable to group similar patterns together and represent them using one single pattern.Frequent closed pattern is proposed for this purpose[14].Let X be a pattern and S be the set of patterns appearing in the same set of transactions as X,that is,S={Y|T(Y)=T(X)}.The longest pattern in S is called a closed pattern,and all the other patterns in S are subsets of it.The closed pattern of S is selected to represent all the patterns in S.The set of frequent closed patterns is a lossless representation of the complete set of frequent patterns.That is,all the frequent patterns and their exact support can be recovered from the set of frequent closed patterns.The number of frequent closed patterns can be much smaller than the total number of frequent patterns, but it can still be tens of thousands or even more. Frequent closed patterns group patterns supported by ex-actly the same set of transactions together.This condition is too restrictive.Xin et al.[23]relax this condition to fur-ther reduce pattern set size.They propose the concept of δ-covered to generalize the concept of frequent closed pat-To appear in Proc. KDD 2012.tern.A pattern X1isδ-covered by another pattern X2if X1 is a subset of X2and(supp(X1)−supp(X2))/supp(X1)≤δ. The goal is toﬁnd a minimum set of representative pat-terns that canδ-cover all frequent patterns.Whenδ=0,the problem corresponds toﬁnding all frequent closed patterns. Xin et al.show that the problem can be mapped to a set cover problem.They develop two algorithms,RPglobal and RPlocal,to solve the problem.RPglobalﬁrst generates the set of patterns that can beδ-covered by each pattern,and then employs the well-known greedy algorithm[8]for the set cover problem toﬁnd representative patterns.The optimal-ity of RPglobal is determined by the optimality of the greedy algorithm,so the solution produced by RPglobal is almost the best solution we can possibly have in practice.However, RPglobal is very time-consuming and space-consuming.It is feasible only when the number of frequent patterns is not large.RPlocal is developed based on FPClose[10].It inte-grates frequent pattern mining with representative pattern ﬁnding.RPlocal is very eﬃcient,but it produces much more representative patterns than RPglobal.In this paper,we analyze the bottlenecks forﬁnding a mini-mum representative pattern set and develop two algorithms, MinRPset and FlexRPset,to solve the problem.Algorithm MinRPset is similar to RPglobal,but it utilizes several tech-niques to reduce running time and memory usage.In par-ticular,MinRPset uses a tree structure called CFP-tree[13] to store frequent patterns compactly.The CFP-tree struc-ture also supports eﬃcient retrieval of patterns that areδ-covered by a given pattern.Our experiment results show that MinRPset is only several times slower than RPlocal, while RPglobal is several orders of magnitude slower.Algo-rithm FlexRPset is developed based on MinRPset.It pro-vides one extra parameter K which allows users to make a trade-oﬀbetween eﬃciency and the number of represen-tative patterns selected.When K=∞,FexRPset is the same as MinRPset.With the decrease of K,FlexRPset be-comes faster,but it produces more representative patterns. When K=1,FlexRPset is slightly faster than RPlocal,and it still produces fewer representative patterns than RPlocal in almost all casese.The rest of the paper is organized as follows.Section2in-troduces related work.Section3gives the formal problem deﬁnition.The two algorithms,MinRPset and FlexRPset, are described in Section4and Section5respectively.Ex-periment results are reported in Section6.Finally,Section 7concludes the paper.2.RELATED WORKThe number of frequent patterns can be very large.Besides frequent closed patterns,several other concepts,such as gen-erators[5],non-derivable patterns[7],maximal patterns[12], top-k frequent closed patterns[19]and redundancy-aware top-k patterns[22],have been proposed to reduce pattern set size.The number of generators is larger than that of closed patterns.Furthermore,the set of generators itself is not lossless.It requires a border to be lossless[6].Non-derivable patterns are generalizations of generators.A bor-der is also needed to make non-derivable patterns lossless. The number of maximal patterns is much smaller than the number of closed patterns.All frequent patterns can be recovered from maximal patterns,but their support infor-mation is lost.Another work that also ignores the support information is[3].It selects k patterns that best cover a collection of patterns.Frequent closed patterns preserve the exact support of all frequent patterns.In many applications,knowing the ap-proximate support of frequent patterns is suﬃcient.Several approaches have been proposed to make a trade-oﬀbetween pattern set size and the precision of pattern support.The work by Xin et al.[23]described in Section1is one such ap-proach.Another approach proposed by Pei et al.[15]mines a minimal condensed pattern-base,which is a superset of the maximal pattern set.Pei et e heuristic algorithms toﬁnd condensed pattern-bases.All frequent patterns and their support can be restored from a condensed pattern-base with error guarantee.Yan et al.[24]use proﬁles to summarize patterns.A proﬁle consists of a master pattern,a support and a probability dis-tribution vector which contains the probability of the items in the master pattern.The set of patterns represented by a proﬁle are subsets of the master pattern,and their support is calculated by multiplying the support of the proﬁle and the probability of the corresponding items.To summarize a collection of patterns using k proﬁles,Yan et al.partition the patterns into k clusters,and use a proﬁle to describe each cluster.There are several drawbacks with this proﬁle-based approach:1)It makes contradictory assumptions.On one hand,the patterns represented by the same proﬁle are sup-posed to be similar in both item composition and supporting transactions,thus the items in the same proﬁle are expected to be strongly correlated.On the other hand,based on how the support of patterns are calculated from a proﬁle,the items in the same proﬁle are expected to be independent. It is hard to make a balance between the two contradicting requirements.2)There is no error guarantee on the esti-mated support of patterns.3)The proposed algorithm for generating proﬁles is very slow because it needs to scan the original dataset repeatedly.4)The support of a pattern is not determined by a single proﬁle,but by all the proﬁles whose master pattern is a superset of the pattern.Thus it is very costly to recover the support of a pattern using proﬁles.5)The boundary between frequent patterns and infrequent patterns cannot be determined using proﬁles. Several improvements have been made to the proﬁle-based approach.Jin et al.[11]develop a regression-based ap-proach to minimize restoration error.They cluster patterns based on restoration errors instead of similarity between pat-terns,thus their approach can achieve lower restoration er-ror.However,there is still no error guarantee on the restored support.CP-summary[16]uses conditional independence to reduce restoration error.It adds one more component to each proﬁle:a pattern base,and the new proﬁle is called c-proﬁle.The items in a c-proﬁle are expected to be in-dependent with respect to the pattern base.CP-summary provides error guarantee on estimated support.However, patterns of a c-proﬁle often share little similarity,so a c-proﬁle is not representative of its patterns any more.Proﬁles can be considered as generalizations of closed pat-terns.Wang et al.[18]make generalization on another con-cise representation of frequent patterns—non-derivable pat-terns.They use Markov Random Field(MRF)to summa-rize frequent patterns.The support of a pattern is estimated from its subsets,which is similar to non-derivable patterns. Markov Random Field model is not as intuitive as proﬁles, and it is also expensive to learn.It does not provide error guarantee on estimated support either.3.PROBLEM STATEMENTWe follow the problem deﬁnition in[23].The distance be-tween two patterns is deﬁned based on their supporting transaction sets.Definition1(D(X1,X2)).Given two patterns X1and X2,the distance between them is deﬁned as D(X1,X2)= 1−|T(X1)∩T(X2)||T(X1)∪T(X2)|.Definition2(ǫ-covered).Given a real numberǫ∈[0,1]and two patterns X1and X2,we say X1isǫ-covered by X2if X1⊆X2and D(X1,X2)≤ǫ.In the above deﬁnition,condition X1⊆X2ensures that the two patterns have similar items,and condition D(X1,X2)≤ǫensures that the two patterns have similar supporting trans-action sets and similar support.Based on the deﬁnition,a patternǫ-covers itself.Lemma1.Given two patterns X1and X2,if pattern X1 isǫ-covered by pattern X2and we use supp(X2)to approxi-mate supp(X1),then the relative error supp(X1)−supp(X2)supp(X1)isno larger thanǫ.Proof.supp(X1)−supp(X2)supp(X1)=1−supp(X2)supp(X1)=1−|T(X2)||T(X1)|≤1−|T(X1)∩T(X2)||T(X1)∪T(X2)|≤ǫ.Lemma2.If a frequent pattern X1isǫ-covered by pattern X2,then supp(X2)≥min sup·(1−ǫ).Proof.Based on Lemma1,1−supp(X2)supp(X1)≤ǫ,so we have supp(X2)≥supp(X1)·(1−ǫ)≥min sup·(1−ǫ).Our goal here is to select a minimum set of patterns that canǫ-cover all the frequent patterns.The selected patterns are called representative patterns.Based on Lemma1,the restoration error of all frequent patterns is bounded byǫ. We do not require representative patterns to be frequent. Based on Lemma2,the support of representative patterns must be no less than min sup·(1−ǫ).The problem is how to ﬁnd a minimum representative pattern set?In the next two sections,we describe two algorithms to solve the problem.4.THE MINRPSET ALGORITHMLet F be the set of frequent patterns in a dataset D with respect to threshold min sup,andˆF be the set of patterns with support no less than min sup·(1−ǫ)in D.Obviously, F⊆ˆF.Given a pattern X∈ˆF,we use C(X)to denote the set of frequent patterns that can beǫ-covered by X.We have C(X)⊆F.If X is frequent,we have X∈C(X).A straightforward algorithm forﬁnding a minimum repre-sentative pattern set is as follows.First we generate C(X) for every pattern X∈ˆF,and we get|ˆF|sets.The elements of these sets are frequent patterns in F.Let S={C(X)|X∈ˆF}.Finding a minimum representative pattern set is nowequivalent toﬁnding a minimum number of sets in S that can cover all the frequent patterns in F.This is a set cover problem,and it is NP-hard.We use the well-known greedy algorithm[8]to solve the problem,which achieves an ap-proximation ratio of k i=11i,where k is the maximal size of the sets in S.We call this simple algorithm MinRPset.The greedy algorithm is essentially the best-possible poly-nomial time approximation algorithm for the set cover prob-lem.Our experiment results have shown that it usually takes little time toﬁnish.Generating C(X)s is the main bottle-neck of the MinRPset algorithm when F andˆF are large because we need toﬁnd C(X)s over a large F for a large number of patterns inˆF.We use the following techniques to improve the eﬃciency of MinRPset:1)consider closed pat-terns only;2)use a structure called CFP-tree toﬁnd C(X)s eﬃciently;and3)use a light-weight compression technique to compress C(X)s.4.1Considering closed patterns onlyA pattern is closed if all of its supersets are less frequent than it.If a pattern X1is non-closed,then there exists another pattern X2such that X1⊂X2and supp(X2)=supp(X1).Lemma3.Given two patterns X1and X2such that X1⊆X2and supp(X1)=supp(X2),if X2isǫ-covered by a pat-tern X,then X1must beǫ-covered by X too.The above lemma directly follows from Deﬁnition2.It im-plies that instead of covering all frequent patterns,we can cover frequent closed patterns only,which leads to the fol-lowing lemma.Lemma4.Let F be the set of frequent patterns in a dataset D with respect to a threshold min sup.If a set of patterns Rǫ-covers all the frequent closed patterns in F,then Rǫ-covers all the frequent patterns in F.Lemma5.Given two patterns X1and X2such that X1⊆X2and supp(X1)=supp(X2),if a pattern X isǫ-covered by X1,then X must beǫ-covered by X2too.This lemma also directly follows from Deﬁnition2.It sug-gests that we can use closed patterns only to cover all fre-quent patterns.The number of frequent closed patterns can be orders of magnitude smaller than the total number of frequent pat-terns.Consider only closed patterns improves the eﬃciency of the MinRPset algorithm in two aspects.On one hand,itTable 1:Anexample dataset D TID Transactions 1a,c,e,f,m,p 2b,e,v3a,b,f,m,p 4d,e,f,h,p 5a,c,d,m,v 6a,c,h,m,s 7a,f,m,p,u 8a,b,d,f,g Table 2:Frequent patterns (minsup =3)ID Itemsets ID itemsets ID itemsets 1a:69ac:317acm:32b:310af:418afm:33c:311am:519afp:34d:312ap:320amp:35e:313cm:321fmp:36f:514fm:322afmp:37m:515fp:48p:416mp:3Figure 1:CFP-tree constructed on the frequent pat-terns in Table 2reduces the size of individual C (X )s since now they contain only frequent closed patterns.On the other hand,it reduces the number of patterns whose C (X )needs to be generated as now we need to generate C (X )s for closed patterns only.4.2Using CFP-tree to ﬁnd C (X )s efﬁcientlyThe CFP-tree structure is specially designed for storing and querying frequent patterns [13].It resembles a set-enumer-ation tree [17].We use an example dataset D in Table 1to illuminate its structure.Table 2shows all the frequent pat-terns in D when min sup =3.The CFP-tree constructed from the frequent patterns is shown in Figure 1.Each node in a CFP-tree is a variable-length array.If a node contains multiple entries,then each entry contains exactly one item.If a node has only one entry,then it is called a singleton node .Singleton nodes can contain more than one item.For example,node 2in Figure 1is a singleton node with two items m and a .An entry E stores several pieces of information:(1)m items (m ≥1),(2)the support of E ,(3)a pointer pointing to the child node of E and (4)the id of the entry which is assigned using preordering.In the rest of this paper,we use E.items ,E.support ,E.child and E.preorder to denote the above ﬁelds.Every entry in a CFP-tree represents one or more patterns with the same support,and these patterns contain the items on the path from the root to the entry.Items contained insingleton nodes are optional.Let E be an entry,X m be the set of items in the multiple-entry nodes and X s be the set of items in the singleton nodes on the path from the root to the parent of E respectively.The set of patterns represented by E is {X m ∪Y ∪Z |Y ⊆X s ,Z ⊆E.items,Z =∅}.The longest pattern represented by E is X m ∪X s ∪E.items .Let us look at an example.Node 4contains only one entry.For this entry,we have X m ={p },X s ={f }and E.items ={m,a }.Hence node 4represents 6itemsets:{p,m },{p,a },{p,m,a },{p,f,m },{p,f,a }and {p,f,m,a }.We use E.pattern to denote the longest pattern represented by E .The above feature makes CFP-tree a very compact structure for storing frequent patterns.The number of entries in a CFP-tree is much smaller than the total number of patterns stored in the tree.For each entry,we consider its longest pattern only based on Lemma 3and Lemma 5.For an entry E ,only its longest pattern can be closed.Other patterns of E that are shorter than the longest pattern cannot be closed based on the deﬁnition of closed patterns.If the longest pattern of an entry is not closed,then we call the entry a non-closed entry .The CFP-tree structure has the following property.Property 1.In a multiple-entry node,the item of an entry E can appear in the subtrees pointed by entries before E ,but it cannot appear in the subtrees pointed by entries after E .For example,in the root node of Figure 1,item p is allowed to appear in the subtrees pointed by entries b ,c ,d and e ,but it is not allowed to appear in the subtrees pointed by entries f ,m and a .This property implies the following lemma.Lemma 6.In a CFP-tree,the supersets of a pattern can-not appear on the right of the pattern.They appear either on the left of the pattern or in the subtree pointed by the pattern.4.2.1Finding one C (X )Given a pattern X ,C (X )contains the subsets of X that can be ǫ-covered by X .CFP-tree supports eﬃcient retrieval of subsets of patterns.To ﬁnd the subsets of a pattern X in a CFP-tree,we simply traverse the CFP-tree and match the items of the entries against X .For an entry E in a multiple-entry node,if its item appears in X ,then entry E represents some subsets of X and the search is continued on its subtree.Otherwise,entry E and its subtree is skipped because all the patterns in the subtree of E contain E.items /∈X ,and these patterns cannot be subsets of X .An entry E in a singleton node can contain items not in X ,and these items are simply ignored.Algorithm 1shows the pseudo-codes for retrieving C (X ).Initially,cnode is the root node of the CFP-tree.Parameter Y contains the set of items to be searched in cnode .It is set to X initially.Once an entry E is visited,the item of E is removed from Y when Y is passed to the subtree of E (line 8,18).The item of E is also excluded when Y is passed to the entries after E (line 21).This is because the item ofAlgorithm 1Search CX AlgorithmInput:cnode is a CFP-tree node;//cnode is the root node initially.Y is the set of items to be searched in cnode ;//Y =X initially.supp (X )is the support of X ;Output:C (X );Description:1:if cnode contains only one entry E then2:if E.support ==supp (X )AND E.pattern ⊂X then 3:Mark E as non-closed;4:if E is not marked as non-closed then 5:if E.items Y =∅AND E.support ≤supp (X )(1−ǫ)then 6:Put E.preorder into C (X );7:if E.child =NULL AND Y −E.items =∅then 8:Search CX(E.child ,Y −E.items ,supp (X ));9:else if cnode contains multiple entries then10:for each entry E ∈cnode from left to right do 11:if E.items ∈Y then 12:if E.support ==supp (X )AND E.pattern ⊂Xthen13:Mark E as non-closed;14:if E is not marked as non-closed then15:if E.support ≤supp (X )(1−ǫ)then 16:Put E.preorder into C (X );17:if E.child =NULL AND Y −E.items =∅then 18:Search CX(E.child ,Y −E.items ,supp (X ));19:if supp (E.pattern ∪Y )>supp (X )(1−ǫ)then 20:return ;21:Y =Y −E.items ;E cannot appear in the subtrees pointed by entries after E based on Property 1.During the search of C (X )s,we also mark non-closed pat-terns.If the longest pattern of E is a proper subset of X and E.support =supp (X ),then E is marked as non-closed (line 2-3,12-13),and it is skipped in subsequent search.The early termination technique.If a pattern is ǫ-covered by X ,then its support must be no larger than supp (X )(1−ǫ)based on Deﬁnition 2.We use this requirement to further improve the eﬃciency of Algorithm 1.Given an en-try E in a multiple-entry node,after we visit the subtree ofE ,if we ﬁnd supp (E.pattern ∪Y )>supp (X )(1−ǫ),where Y is the set of items that is passed to E ,then there is no need to visit the subtrees pointed by entries after E (line 19-0).The reason being that all the subsets of X in these subtrees must be subsets of (E.pattern ∪Y ),and their support must belarger than supp(X )(1−ǫ)too based on the anti-monotone prop-erty.We call this pruning technique the early termination technique.4.2.2Finding C (X )s of all closed patternsAlgorithm 2shows the pseudo-codes for generating all C (X )s.It traverses the CFP-tree in depth-ﬁrst order from left to ing this traversal order,the supersets of a pattern X that are on the left of X are visited before X .If the support of X is the same as one of these supersets,then X should be marked as non-closed when Search CX is called for that superset.If X is not marked as non-closed when X is visited,it means that X is more frequent than all its supersets on its left.Based on Lemma 6,the supersets of a pattern appear either on the left of the pattern or in thesubtree pointed by the pattern.If X is also more frequentthan its child entries,then X must be closed.The conditions listed at line 2and line 3ensure that Algorithm 2generates C (X )s for only closed patterns.Algorithm 2DFS Search CXs AlgorithmInput:cnode is a CFP-tree node;//cnode is the root node initially.Output:C (X )s;Description:1:for each entry E ∈cnode from left to right do 2:if E is not marked as non-closed then 3:if E is more frequent than its child entries then 4:X =E.pattern ;5:C (X )=Search CX(root ,X ,E.support );6:if E.child =NULL then 7:DFS Search CXs(E.child );In Algorithm 2,if an entry E is marked as non-closed be-cause it has the same support as one of its supersets on its left,then all the patterns in the subtree pointed by E are non-closed.We can safely skip E and its subtree in subsequent traversal (line 2).The same pruning is done in Algorithm 1(line 4,14).This observation has been used in almost all frequent closed pattern mining algorithms to prune non-closed patterns [10,20].4.3Compressing C (X )sIn a CFP-tree,each entry E has an id,which is denoted as E.preorder .In Algorithm 1,we put the ids of entries in C (X )s if E is ǫ-covered by X (line 6,16).Each id takes 4bytes.Both the total number of C (X )s and the size of indi-vidual C (X )s grow with the number of frequent (closed)pat-terns.When the number of frequent closed patterns is large,the total size of C (X )s can be very large.If the main mem-ory cannot accommodate all C (X )s,the greedy set cover algorithm becomes very slow.To alleviate this problem,we compress C (X )s using a light-weight compression technique [21].Each entry id occupies one or more bytes depending on its value.To reduce the number of bytes needed for storing entries ids,we sort the entry ids in ascending order and store the diﬀerences be-tween consecutive ids instead.Our experiment results show that this compression technique can reduce the space needed for storing C (X )s by about three quarters.Algorithm 3MinRPset AlgorithmDescription:1:Mine patterns with support ≥min sup ·(1−ǫ)and store them in a CFP-tree;let root be the root node of the tree;2:DFS Search CXs(root );3:Remove non-closed entries from C (X )s;4:Apply the greedy set cover algorithm on C (X )s to ﬁnd rep-resentative patterns;5:Output representative patterns;Algorithm 3shows the pseudo-codes of the MinRPset algo-rithm,and it calls Algorithm 2to ﬁnd C (X )s.Note that we store all patterns,including non-closed patterns,with support no less than min sup ·(1−ǫ)in a CFP-tree (line 1).Non-closed patterns are identiﬁed during the search of C (X )s.Hence it is possible that some C (X )s contains somenon-closed entries.These non-closed entries are removed from C(X)s(line3)before the greedy set cover algorithm is applied.5.THE FLEXRPSET ALGORITHMWhen the number of frequent patterns is large on a dataset, the MinRPset algorithm may become very slow since it needs to search subsets over a large CFP-tree for a large number of patterns.Furthermore,the set of C(X)s may become too large toﬁt into the main memory.To solve this problem, instead of searing C(X)s for all closed patterns,we can se-lectively generate C(X)s such that every frequent pattern is covered a suﬃcient number of times,in the hope that the greedy set cover algorithm can stillﬁnd a near-optimal solu-tion.Apparently,the fewer the number of C(X)s generated, the more eﬃcient the algorithm is.This is the basic idea of the FlexRPset algorithm.The FlexRPset algorithm uses a parameter K to control the minimum number of times that a frequent pattern needs to be covered.Algorithm4shows how FlexRPset selectively generates C(X)s.The other steps of FlexRPset are the same as those of MinRPset.Algorithm4Flex Search CXs AlgorithmInput:cnode is a CFP-tree node;//cnode is the root node initially.K is the minimum number of times that a frequent closed pattern needs to be covered;Output:C(X)s;Description:1:for each entry E∈cnode from left to right do2:if E is not marked as non-closed then3:if E.child=NULL then4:Flex Search CXs(E.child);5:if E is more frequent than its child entries then6:if(E is frequent AND E is covered less than K times) OR(∃an ancestor entry E′of E such that E′is fre-quent,E′can beǫ-covered by E and E′is covered lessthan K times)then7:X=E.pattern;8:C(X)=Search CX(root,X,E.support);Algorithm4still uses the depth-ﬁrst order to traverse a CFP-tree from left to right.It traverses the subtree of an entry Eﬁrst(line3-4)before it processes entry E(line5-8), which means that when entry E is processed,all the super-sets of E have been processed already based on Lemma6, and entry E cannot be covered any more except by E itself. If E is frequent and it is covered less than K times,then we generate C(E.patterns)to cover E(theﬁrst condition at line6).If E has already be covered at least K times when E is visited,then we look at the ancestor entries of E.For an ancestor entry E′of E,most of its supersets are already processed too when E is visited,hence not many remaining entries can cover E′.If E′is frequent,E′can beǫ-covered by E and E′is covered less than K times,then we also gen-erate C(E.patterns)to cover E′(the second condition at line6).6.EXPERIMENTSIn this section,we study the performance of our algorithms. The experiments were conducted on a PC with2.33Ghz Intel Duo Core CPU and3.25GB memory.Our algorithms were implemented using C++.We downloaded the source codes of RPlocal from the IlliMine package[2].All source codes were compiled using Microsoft Visual Studio2005.6.1DatasetsThe datasets used in the experiments are shown in Table 3.They are obtained from the FIMI repository[1].Table 3shows some basic statistics of these databases:number of transactions(|T|),number of distinct items(|I|),maxi-mum length of transactions(MaxTL)and average length of transactions(AvgTL).Table3:Datasetsdataset|T||I|MaxTL AvgTLaccidents3401834685233.81chess3196753737.00connect675571294343.00mushroom81241192323.00pumsb4904621137474.00pumsb star4904620886350.486.2Comparing with RPlocalTheﬁrst experiment compares MinRPset and FlexRPset with RPlocal.Let N be the number of representative pat-terns generated by an algorithm.Figure2shows the ratio of N to the number of representative patterns generated by RPlocal when min sup is varied.Obviously,the ratio is al-ways1for RPlocal.ǫis set to0.2on mushroom and to0.1 on other datasets.In[23],the authors have shown that the number of representative patterns selected by RPlocal can be orders of magnitude smaller than the number of frequent closed patterns.MinRPset further reduces the number of representative patterns by10%-65%.The FlexRPset algo-rithm generates a similar number of representative patterns with MinRPset when K is large.When K gets smaller,the number of representative patterns generated by FlexRPset increases.When K=1,FlexRPset still generates less repre-sentative patterns than RPlocal in most of the cases. Figure3shows the running time of the several algorithms when min sup is varied.The running time of MinRPset and FlexRPset includes time for mining frequent patterns.The running time of all algorithms increases with the descrease of min sup.MinRPset has similar running time with RPlocal on mushroom.On accidents and pumsb star,when min sup is relatively high,the running time of MinRPset and RPlocal is similar too.In other cases except for dataset pumsb, MinRPset is several times slower than RPlocal.RPglobal is often hundreds of times slower than RPlocal as shown in [23].This indicates the techniques used in MinRPset is very eﬀective in reducing running time.On pumsb,MinRPset is more than10times slower than RPlocal when min sup≤0.7,but it achieves the greatest reduction in the number of representative patterns on this dataset.FlexRPset has similar running time with RPlocal when K is small.When K=10,the running time of FlexRPset is close to that of RPlocal,and the number of representative pat-terns generated by FlexRPset is close to that of MinRPset.。

2016年6月大学英语四级真题第二套

2016年6月大学英语四级真题第二套2016年6月大学英语四级真题（第2套)该真题及答案摘自于巨微英语四级真题逐句精解，中间省略听力原文，详细资料可以关注公众号：巨微英语四六级或者官网渠道获得电子版。

Part I WritingDirections:For this part, you are allowed 30 minutes to write a letter to express your thanks to one of your school teachers upon entering college. You should write at least 120 words but no more than 180 words.Part ⅡListening Comprehensionwill hear two or three questions. Both the news report and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A), B), C) and D). Then mark the corresponding letter on Answer Sheet 1with a single line through the centre.Questions 1 and 2 are based on the news report you have just heard.1. A)How college students can improve their sleep habits.B)Why sufficient sleep is important for college students.D)Whether the Spanish company could offer better service.4. A)Inefficient management. B)Poor ownership structure.C)Lack of innovation and competition.D)Lack of runway and terminal capacity.Questions 5 to 7 are based on the news report you have just heard.5. A)Report the nicotine content of their cigarettes.B)Set a limit to the production of their cigarettes.C)Take steps to reduce nicotine in their products.D)Study the effects of nicotine on young smokers.6. A)The biggest increase in nicotine content tended to be in brands young smokers like.B)Big tobacco companies were frank withtheir customers about the hazards of smoking.C)Brands which contain higher nicotine content were found to be much more popular.D)Tobacco companies refused to discuss the detailed nicotine content of their products.7. A)They promised to reduce the nicotine content in cigarettes.B)They have not fully realized the harmful effect of nicotine.C)They were not prepared to comment on the cigarette study.D)They will pay more attention to the quality of their products.Section BDirections: In this section, you will hear two long conversations. At the end of each conversation, you will hear four questions. Both the conversation and the questions will be spoken only once. After you hear a question, you must choosethe best answer from the four choices marked A), B), C)and D). Then mark the corresponding letter on Answer Sheet 1 with a single line through the centre.Questions 8 to 11 are based on the conversation you have just heard.8. A)Indonesia. B)Holland. C)Sweden.D)England.9.A)Getting a coach who can offer real help.B)Talking with her boyfriend in Dutch.C)Learning a language where it is not spoken .D)Acquiring the necessary ability to socialize .10. A)Listening language programs on the radio.B)Trying to speak it as much as one can.C)Making friends with native speakers.D)Practicing reading aloud as often as possible.11.A)It creates an environment for socializing.B)It offers various courses with credit points.C)It trains young people’s leadership abilities.D)It provides opportunities for language practice.Questions 12 to 15 are based on the conversation you have just heard.12. A)The impact of engine design on rode safety.B)The role policemen play in traffic safety.C)A sense of freedom driving gives.D)Rules and regulations for driving.13. A)Make cars with automatic control.B)Make cars that have better brakes.C)Make cars that are less powerful.D)Make cars with higher standards.14. A)They tend to drive responsibly.B)They like to go at high speed.C)They keep within speed limits.D)They follow traffic rules closely.15.A)It is a bad idea. B)It isnot useful.C)It is as effective as speed bumps . D)It should be combined with education.Section CDirections:In this section, you will hear three passages. At the end of each passage, you will hear three or four questions. Both the passage and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A), B), C)and D).Then mark the corresponding letter on Answer Sheet 1 with a single line through the centre.Questions 16 to 18 are based on the passage you have just heard.16.A)The card got damaged . B)The card was found invalid.C)The card reader failed to do the scanning.D)The card reader broke down unexpectedly.17. A)By converting the credit card with a layer of plastic.B)By calling the credit card company for confirmation.C)By seeking help from the card reader maker Verifone.D)By typing the credit card number into the cash register.18.A)Affect the sales of high-tech appliances.B)Change the life style of many Americans.C)Give birth to many new technological inventions.D)Produce many low-tech fixes for high-tech failures.Questions 19 to 21 are based on the passage you have just heard.19. A)They are set by the dean of the graduate school.B)They are determined by the advising board.C)They leave much room for improvement.D)They vary among different departments.20. A)By consulting the examining committee .B)By reading the Bulletin of Information.C)By contacting the departmental office.D)By visiting the university’s website.21. A)They specify the number of credits students must earn.B)They are harder to meet than those for undergraduates.C)They have to be approved by the examining committee.D)They are the same among various divisions of the university.Questions 22 to 25 are based on the passage you have just heard.22. A)Students majoring in nutrition.B)Students in health classes.C)Ph.D. candidates in dieting.D)Middle and high school teachers.23. A)Its overestimate of the effect of dieting.B)Its mistaken conception of nutrition.C)Its changing criteria for beauty.D)Its overemphasis on thinness.24. A)To illustrate her point that beauty is but skin deep.B)To demonstrate the magic effect of dieting on women.C)To explain how computer images can be misleading.D)To prove that technology has impacted our culture.25. A)To persuade girls to stop dieting.B)To promote her own concept of beauty.C)To establish an emotional connection with students.D)To help students rid themselves of bad living habits.Section ADirections:In this section, thereis a passage with ten blanks.You are required to select one word for each blank from a list of choices given in a word bank following the passage. Read the passage through carefully before making your choices. Each choice in the bank is identified by a letter. Please mark the corresponding letter for each item on Answer Sheet 2with a single line through the centre. You may not use any of the words in the bank more than once.Contrary to popular belief, older people generally do not want to live with their children. Moreover, most adult children 26 every bit as much care and support to their aging parents as was the case in the “good old days”, and mostolder people do not feel 27 .About 80% of people 65years and older have living children, and about 90% of them have 28 contact with their children. About 75% of elderly parents who don’t go to nursing homes live within 30 minutes of at least one of their children.However, 29 having contact with children does not guarantee happiness in old age. In fact, some research has found that people who are most involved with their families have the lowest spirits. This research may be 30 , however, as ill health often makes older people more 31 and thereby increases contact with family members. So it is more likely that poor health, not just family involvement, 32 spirits.Increasingly, researchers have begun to look at the quality of relationships, rather than at the frequency of contact, between the elderly and their children. If parents and children share interests and values and agree on childrearingpractices and religious 33 , they are likely to enjoy each other’s company. Disagreements on such matters can 34 cause problems. If p arents are agreed by their daughter’s divorce, dislike her new husband, and disapprove of how she is raising their grandchildren, 35 are that they are not going to enjoy her visits.Section BDirections: In this section, you are going to read a passage with ten statements attached to it. Eachstatement contains information given in one of the paragraphs. Identify the paragraph from which the information is derived. You may choose a paragraph more than once. Each paragraph is marked with a letter. Answer the questions by marking the corresponding letter on Answer Sheet 2.Could Food Shortages Bring Down Civilization?[A] For many years I have studied globalagricultural, population, environmental and economic trends and their interactions. The combined effects of those trends and the political tensions they generate point to the breakdown of governments and societies. Yet I, too, have resisted the idea that food shortages could bring down not only individual governments but also our global civilization.[B] I can no longer ignore that risk. Ourcontinuing failure to deal with the environmental declines that are underminingthe world food economy forces me to conclude that such a collapse is possible.[C] As demand for food rises faster thansupplies are growing, the resulting food-price inflation puts severe stress on the governments of many countries. Unable to buy grain or grow their own, hungry people take to the streets. Indeed, even before the steep climb in grain prices in 2008, the number of failing states was expanding. If the food situation continues to worsen, entire nations will break down at an ever increasing rate. In the 20th century the main threat to international security was superpower conflict; today it is failing states.[D] States fail when national governments canno longer provide personal security, food security and basic social services such as education and health care. When governments lose their control on power, law and order begin to disintegrate. After a point,countries can become so dangerous that food relief workers are no longer safe and their programs are halted. Failing states are of international concern because they are a source of terrorists, drugs, weapons and refugees(难民), threatening political stability everywhere.[E] The surge in world grain prices in 2007 and2008—and the threat they pose to foodsecurity——has a different, more troublingquality than the increases of the past.During the second half of the 20th century,grain prices rose dramatically several times.In 1972, for instance, the Soviets,recognizing their poor harvest early, quietlycornered the world wheat market. As aresult, wheat prices elsewhere more thandoubled, pulling rice and corn prices upwith them. But this and other price shockswere event-driven——drought in the SovietUnion, crop-shrinking heat in the U.S. CornBelt. And the rises were short-lived: prices typically returned to normal with the next harvest.[F] In contrast, the recent surge in world grainprices is trend-driven, making it unlikely to reverse without a reversal in the trends themselves. On the demand side, those trends include the ongoing addition of more than 70 million people a year, a growing number of people wanting to move up the food chain to consume highly grain-intensive meat products, and the massive diversion(转向) of U.S. grain to the production of bio-fuel.[G] As incomes rise among low-incomeconsumers, the potential for further grain consumption is huge. But that potential pales beside the never-ending demand for crop-based fuels. A fourth of this year’s U.S.grain harvest will go to fuel cars.[H] What about supply? The threeenvironmental trends——the shortage of fresh water, the loss of topsoil and the rising temperatures——are making it increasingly hard to expand the world’s grain supply fast enough to keep up with demand. Of all those trends, however, the spread of water shortages poses the most immediate threat.The biggest challenge here is irrigation, which consumes 70% the world’s fresh water.Millions of irrigation wells in many countries are now pumping water out of underground sources faster than rainfall can refill them.The result is falling water tables(地下水位) in countr ies with half the world’s people, including the three big grain producers——China, India and the U.S.[I] As water tables have fallen and irrigationwells have gone dry, China’s wheat crop, the world’s largest, has declined by 8% since it peaked at 123 million tons in 1997. But water shortages are even more worrying in India.Millions of irrigation wells have significantly lowered water tables in almost every state.[J] As the world’s food security falls to pieces, individual countries acting in their own self-interest are actually worsening the troubles of many. The trend began in 2007, when leading wheat-exporting countries such as Russia and Argentina limited or banned their exports, in hopes of increasing local food supplies and thereby bringing down domestic food prices. Vietnam banned its exports for several months for the same reason. Such moves may eliminate the fears of those living in the exporting countries, but they are creating panic in importing countries that must rely on what is then left for export.[K] In response to those restrictions, grain-importing countries are trying to nail down long-term trade agreements that would lock up future grain supplies.Food-import anxiety is even leading to new efforts by food-importing countries to buy or lease farmland in other countries. In spite of such temporary measures, soaring food prices and spreading hunger in many other countries are beginning to break down the social order.[L] Since the current world food shortage is trend-driven, the environmental trends that cause it must be reversed. We must cut carbon emissions by 80% from their 2006 levels by 2020, stabilize the world’s population at eight billion by 2040, completely remove poverty, and restore forests and soils. There is nothing new about the four objectives. Indeed, we have made substantial progress in some parts of the world on at least one of these——the distribution of family-planning services and the associated shift to smaller families.[M]For many in the development community,the four objectives were seen as positive, promoting development as long as they did not cost too much. Others saw them as politically correct and morally appropriate.Now a third and far more significant motivation presents itself: meeting these goals may be necessary to prevent the collapse of our civilization. Yet the cost we project for saving civilization would amount to less than $200 billion a year, 1/6 of current global military spending. In effect, our plan is the new security budget.36.The more recent steep climb in grain pricespartly results from the fact that more and more people want to consume meat products.37. Social order is breaking down in many countries because of food shortages.38. Rather than superpower conflict, countriesunable to cope with food shortages now constitute the main threat to world security.39. Some parts of the world have seen successful implementation of family planning.40. The author has come to agree that foodshortages could ultimately lead to the collapse of world civilization.41. Increasing water shortages prove to be thebiggest obstacle to boosting the world’s grain production.42. The cost for saving our civilization would beconsiderably less than the world’s current military spending.43. To lower domestic food prices, some countries limited or stopped their grain exports.44. Environmental problems must be solved to ease the current global food shortage.45. A quarter of this year’s American grain harvest will be used to produce bio-fuel for cars.Section CDirections: There are 2 passages in this section. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A), B), C) and D). You should decide on the best choice and mark the corresponding letter on Answer Sheet 2 with a single line through the centre.Passage OneQuestions 46 to 50 are based on the following passage.Declining mental function is often seen as a problem of old age, but certain aspects of brain function actually begin their decline in young adulthood, a new study suggests.The study, which followed more than 2,000 healthy adults between the ages of 18 and 60, found that certain mental functions—including measures of abstract reasoning, mental speed and puzzle-solving—started to dull as early as age 27.Dips in memory, meanwhile, generallybecame apparent around age 37.On the other hand, indicators of a person’s accumulated knowledge—like performance on tests of vocabulary and general knowledge—kept improving with age, according to findings published in the journal Neurobiology of Aging.The results do not mean that young adults need to start worrying about their memories. Most people’s minds function at a high level even in their later years, according to researcher Timothy Salthouse.“These patterns suggest that some types of mental flexibility decrease relatively early in adulthood, but that the amount of knowledge one has, and the effectiveness of integrating it with one’s abilities, may increase throughout all of adulthood if there are no dise ases,” Salthouse said in a news release.The study included healthy, educated adultswho took standard tests of memory, reasoning and perception at the outset and at some point over the next seven years.The tests are designed to detect subtle (细微的) changes in mental function, and involve solving puzzles, recalling words and details from stories, and identifying patterns in collections of letters and symbols.In general, Salthouse and his colleagues found, certain aspects of cognition (认知能力) generally started to decline in the late 20s to 30s.The findings shed light on normal age-related changes in mental function, which could aid in understanding the process of dementia (痴呆), according to the researchers.“By following individuals over time,” Salthouse said, “we gain insight in cognition changes, and may possibly discover ways to slow the rate of decline.”The researchers are currently analyzing thestudy participants’ health and lifestyle to see which factors might influence age-related cognitive changes.46. What is the common view of mental function?A)It varies from person to person.B)It weakens in one’s later years.C)It gradually expands with age. D)It indicates one’s health condition.47. What does the new study find about mental functions?A)Some diseases inevitably lead to their decline.B)They reach a peak at the age of 20 for most people.C)They are closely related to physical and mental exercise.D)Some of them begin to decline when people are still young.48. What does Timothy Salthouse say about people’s minds in most cases?A)They tend to decline in people’s later years.B)Their flexibility determines one’s abilities.C)They function quite well even in old age.D)Their functioning is still a puzzle to be solved.49. Although people’s minds may function less flexibly as they age, they _____.A)may be better at solving puzzlesB)can memorize things with more easeC)may have greater facility in abstract reasoningD)can put what they have learnt into more effective use50. According to Salthouse, their study may help us_____.A)find ways to slow down our mental declineB)find ways to boost our memoriesC)understand the complex process of mental functioningD)understand the relation between physical and mental healthPassage TwoQuestions 51 to 55 are based on the following passage.The most important thing in the news last week was the rising discussion in Nashville about the educational needs of children. The shorthand(简写)educators use for this is “pre-K”—meaning instruction before kindergarten—and the big idea is to prepare 4-year-olds and even younger kids to be ready to succeed on their K-12 journey.But it gets complicated. The concept hasmultiple forms, and scholars and policymakers argue about the shape, scope and cost of the ideal program.The federal Head Start program, launched 50 years ago, has served more than 30 million children. It was based on concepts developed at Vanderbilt University’s Peabody College by Susan Gray, the legendary pioneer in early childhood education research.A new Peabody study of the Tennessee Voluntary Pre-K program reports that pre-K works, but the gains are not sustained through the third grade. It seems to me this highlights quality issues in elementary schools more than pre-K, and indicates longer-term success must connect pre-K with all the other issues related to educating a child.Pre-K is controversial. Some critics say it is a luxury and shouldn’t be free to families able to pay. Pre-K advocates insist it is proven and will succeed if integrated with the rest of the child’sschooling. I lean toward the latter view.This is, in any case, the right conversation to be having now as Mayor Megan Barry takes office. She was the first candidate to speak out for strong pre-K programming. The important thing is for all of us to keep in mind the real goal and the longer, bigger picture.The weight of the evidence is on the side of pre-K that early intervention (干预)works. What government has not yet found is the political will to put that understanding into full practice with a sequence of smart schooling that provides the early foundation.For this purpose, our schools need both the talent and the organization to educate each child who arrives at the schoolhouse door. Some show up ready, but many do not at this critical time when young brains are developing rapidly.51.What does the author say about pre-kindergarten education?A)It should cater to the needs of individual children.B)It is e ssential to a person’s future academic success.C)Scholars and policymakers have different opinions about it.D)Parents regard it as the first phase of children’s development.52.What does the new Peabody study find?A)Pre-K achievements usually do not last long.B)The third grade marks a new phase of learning.C)The third grade is critical to children’s development.D)Quality has not been the top concern of pre-K programs.53.When does the author think pre-K works the best?A)When it is accessible to kids of all families.B)When it is made part of kids’ education.C)When it is no longer considered a luxury.D)When it is made fun and enjoyable to kids.54.What do we learn about Mayor Megan Barry?A)She knows the real goal of education.B)She is a mayor of insight and vision.C)She has once run a pre-K program.D)She is a firm supporter of pre-K.55.What does the author think is critical to kids’ education?A)Teaching method. B)Kids’ interest.C)Early intervention.D)Parents’ involvement.Directions:For this part, youare allowed 30 minutes totranslate a passage fromChinese into English. Youshould write your answer on Answer Sheet 2.在山东省潍坊市，风筝不仅仅是玩具，而且还是这座城市文化的标志。

高二英语机器学习单选题50题

高二英语机器学习单选题50题1.Machine learning is a field of study that focuses on the development of algorithms that can learn from ___.A.dataB.experienceC.intuitionD.opinion答案：A。

本题主要考查机器学习的基本概念。

机器学习是通过数据进行学习的，选项A“data”符合题意。

选项B“experience”通常指人的经验，机器学习主要依据数据而非人的经验。

选项C“intuition”是直觉，机器学习是基于数据和算法的，不是直觉。

选项D“opinion”是观点，机器学习不是基于观点进行学习。

2.The main goal of machine learning is to ___.A.predict future eventsB.create new algorithmsC.solve complex equationsD.store large amounts of data答案：A。

机器学习的主要目标是根据已有数据预测未来事件，选项 A 正确。

选项B“create new algorithms”不是机器学习的主要目标，虽然在研究中可能会产生新算法，但不是主要目的。

选项C“solve complex equations”是数学等领域的任务，不是机器学习的主要目标。

选项D“store large amounts of data”只是存储数据，不是机器学习的目标。

3.Machine learning algorithms can be used in ___.A.image recognitionB.math calculationsC.physical experimentsD.literary analysis答案：A。

机器学习算法可以用于图像识别，选项A 正确。

Filtering Frequent Spatial Patterns with Qualitative Spatial Reasoning

Filtering Frequent Spatial Patterns withQualitative Spatial ReasoningVania Bogorny a Bart Moelans a Luis Otavio Alvares aba Theoretical Computer Science Group,Hasselt University&Transnational University of Limburg,Belgiumb Instituto de Inform´a tica–Universidade Federal do Rio Grande do Sul,BrazilThe full version of this paper appeared in the2007IEEE Workshop Proceedings of the23rdInternational Conference on Data Engineering(ICDE2007)[6]1IntroductionThe huge amount of patterns generated by frequent pattern mining algorithms has been extensively ad-dressed in the last few years.Different measures have been proposed to evaluate how interesting association rules are.However,according to[3]it is difﬁcult to come up with a single metric that quantiﬁes the“inter-estingness”or“goodness”of an association rule.In most approaches,non-interesting rules are eliminated during the rule generation,i.e.,a posteriori,when frequent itemsets have already been generated.In spatial frequent pattern mining the number of non-interesting association rules can increase even fur-ther than in transactional pattern mining.Geographic data have semantic dependencies and spatial properties which in many cases are well known and non-interesting for data mining.In the geographic domain,not only well known geographic dependencies(e.g.,is gasStation→touches street)generate a large number of patterns without novel and useful knowledge.Different spatial predicates may contain the same geographic object type.In transactional frequent pattern mining items have binary values,and do either participate or not in a transaction.For instance,the item milk is either present or not in a transaction t.In spatial frequent pattern mining the same spatial object(item)may have different qualitative spatial relationships with the target feature(transaction),and by consequence participate more then once in the same transaction t.For instance,a city C may contain an instance i1of river,be crossed by an instance i2of river,or even touch an instance i3of river.Different spatial relationships with the same geographic object type will generate associations such as contains River→touches River when data are considered at general granularity levels[8].It is well known that a city does not touch a river because it also contains a river.Such kind of rule is non-interesting for most applications.An interesting association rule would be the combination of any of these two predicates with a different geographic ob-ject type or some non-spatial attribute.For instance:contains River→W aterP ollution=high or touches River→exportationRate=high.In[5],Apriori-KC is proposed.This method made some changes on Apriori[1]to eliminate well known geographic patterns using background knowledge.In[4]this method is extended with an additional step where not only frequent itemsets are reduced,but input space is reduced as much as possible,since this is still the most efﬁcient way for pruning frequent patterns.In[7]the closed frequent pattern mining approach is applied to the geographic domain,eliminating both well known dependencies and redundant frequent itemsets.In this paper we extended the method presented in[5]to reduce the number of non-interesting spatial patterns using qualitative spatial reasoning.Not only the data is considered,but its semantics is taken into account,and frequent patterns that contain the same feature type are removed a priori.The method proposed in this paper is more effective and efﬁcient then most other methods which perform pruning after the rule generation,since our method explores the anti-monotone constraint of Apriori[1] and prunes non-interesting patterns during the frequent set generation.Other transactional pattern mining(a)Frequent Geographic Pattern with Apriori,Apriori-KC,and Apriori-KC+(b)Computational Time to Generate Frequent Geographic Patterns with Apriori,Apriori-KC,and Apriori-KC+Figure 1:Experiments on real dataapproaches such as [2,9]remove redundant frequent patterns and association rules exploiting support and conﬁdence constraints,while our method is independent of such thresholds.In these approaches “redundant”rules are eliminated by frequent itemset pruning,but “non-interesting”and “meaningless”rules are still generated.In Figure 1(a)it is clear that there is a reduction of the number of frequent patterns,and in Figure 1(b)the efﬁciency of the method is conﬁrmed.AcknowledgementsThis research has been funded by the Brazilian agency CAPES,the European Union (FP6-IST-FET pro-gramme,Project n.FP6-14915,GeoPKDD:Geographic Privacy-Aware Knowledge Discovery and Deliv-ery),and by the Research Foundation Flanders (FWO-Vlaanderen),Research Project G.0344.05.References[1]Rakesh Agrawal and Ramakrishnan Srikant.Fast algorithms for mining association rules in largedatabases.In VLDB ,pages 487–499,1994.[2]Yves Bastide,Nicolas Pasquier,Raﬁk Taouil,Gerd Stumme,and LotﬁLakhal.Mining minimal non-redundant association rules using frequent closed itemsets.In CL ’00:Proceedings of the First Interna-tional Conference on Computational Logic ,pages 972–986,London,UK,2000.Springer-Verlag.[3]Roberto J.Bayardo and Rakesh Agrawal.Mining the most interesting rules.In KDD ,pages 145–154,1999.[4]Vania Bogorny,Sandro Camargo,Paulo Engel,and Luis Otavio Alvares.Mining frequent geographicpatterns with knowledge constraints.In ACM-GIS ,pages 139–146.ACM,2006.[5]Vania Bogorny,Sandro Camargo,Paulo Engel,and Luis Otavio Alvares.Towards elimination of wellknown patterns in spatial association rule mining.In IS ,pages 532–537.IEEE Computer Society,2006.[6]Vania Bogorny,Bart Moelans,and Luis Otavio Alvares.Filtering frequent spatial patterns with qual-itative spatial reasoning.In Proceedings of the 22nd International Conference on Data Engineering Workshops,ICDE 2007,15–16&20April 2007,Istanbul,Turkey ,pages 527–535,2007.[7]Vania Bogorny,Joao Valiati,Sandro Camargo,Paulo Engel,Bart Kuijpers,and Luis Otavio Alvares.Mining maximal generalized frequent geographic patterns with knowledge constraints.In ICDM ,pages 813–817.IEEE Computer Society,2006.[8]Jiawei Han.Mining knowledge at multiple concept levels.In CIKM ,pages 19–24.ACM,1995.[9]Mohammed J.Zaki.Generating non-redundant association rules.In KDD ’00:Proceedings of the sixthACM SIGKDD international conference on Knowledge discovery and data mining ,pages 34–43,New York,NY ,USA,2000.ACM Press.。

学术英语写作智慧树知到课后章节答案2023年下天津外国语大学

学术英语写作智慧树知到课后章节答案2023年下天津外国语大学天津外国语大学第一章测试1.What steps are involved in writing? （）A:PrewritingB:Revising and editingC:Writing the first draftD:Rewriting答案:Prewriting;Revising and editing;Writing the first draft2.The objectives of the course include （）A:To improve students’ thinking ability via choosing a topic, sourcinginformation, writing different parts of a project paper including introduction, literature review, methods, findings, discussions and conclusionB:To improve students’ writing and reading proficiency in EnglishC:To improve students’ capability of carrying out research by going through the process of writing a project paperD:To improve students’ cultural competence through learning western ways of thinking in English writing答案:To improve students’ thinking ability via choosing a topic,sourcing information, writing different parts of a project paperincluding introduction, literature review, methods, findings,discussions and conclusion;To im prove students’ writing and reading proficiency in English;To improve students’ capability of carrying out research by goingthrough the process of writing a project paper;To improve students’ cultural competence through learning westernways of thinking in English writing3.In freewriting, the writer needs to make everything perfect.（）A:错 B:对答案:错4.The relationship between reading and writing can be described as（）A:When you start learning writing, you will read differently.B:Reading is the input, while writing is the output of language.C:When you start learning writing, you will improve the awareness ofaccumulating language, information and idea for various topics, which will consequently change the way you read.D:Reading and writing are reciprocal activities; the outcome of a readingactivity can serve as input for writing, and writing can lead a student tofurther reading resources.答案:When you start learning writing, you will read differently.;Reading is the input, while writing is the output of language.;When you start learning writing, you will improve the awareness ofaccumulating language, information and idea for various topics, which will consequently change the way you read.;Reading and writing are reciprocal activities; the outcome of a reading activity can serve as input for writing, and writing can lead a student to further reading resources.5.The functions of writing include （）A:The discipline of writing will strengthen your skills as a reader and listener B:Writing will make you a strong thinker and writing allows you to organize your thoughts in clear and logical waysC:Writing encourages you to seek worthwhile questionsD:Writing helps you refine and enrich your ideas based on feedback fromreaders答案:The discipline of writing will strengthen your skills as a readerand listener;Writing will make you a strong thinker and writing allows you toorganize your thoughts in clear and logical ways;Writing encourages you to seek worthwhile questions;Writing helps you refine and enrich your ideas based on feedback fromreaders第二章测试1. A thesis statement should be one single sentence, including only one idea. ( ）A:对 B:错答案:对2.An essay should include at least three specific details to be well-developed. ( ）A:对 B:错答案:错3.The topic sentence for each body paragraph should be fairly specific becauseeach body paragraph deals with only one of the many things stated in thethesis statement. ( ）A:错 B:对答案:对4.Living with my ex-roommate was unbearable. First, she thought everythingshe owned was the best. Secondly, she possessed numerators filthy habits.Finally, she constantly exhibited immature behavior.Read this paragraph and decide which statement is NOT TRUE? （）。

2018年12月大学英语六级考试真题答案与详解一

2018年12⽉⼤学英语六级考试真题答案与详解⼀~2018年12⽉⼤学英语六级考试真题答案与详解⼀梦想不会辜负每⼀个努⼒的⼈(第3套)Part I Writing本篇话题是“如何平衡学业和课外活动”，这与考⽣的学习⽣活密切相关。

在具体⾏⽂⽅⾯,考⽣可以开篇引出话题;然后针对这⼀问题提出⾃⼰的建议;最后总结全⽂，重述论点或升华主题。

旳厝作提纲'—、引出话题:适当地参加课⼣⼘活动不仅能促进学习，⽽且能提⾼综合能⼒(promote academic studyenhance our overallactivities more rationally)如何平衡学业和课外活动许多学⽣和他们的⽗母担⼼花时间参加课外活动会妨碍学习，这是可以理解的。

但在我看来，只要我们能在两者之间取得平衡,适当地参加课外活动不仅能促进学习'⽽且能提⾼我们的综合能⼒。

⾸先，合理安排课业并⾼效地完成是明智之举，因为只有这样，我们才能分配出额外的时间和精⼒参加课外201⾉12/6(第3套)梦想不会辜负每⼀个努⼒的⼈活珈并且不会对我们的学习产⽣负⾯影响。

其次,应该只将时间花在我们想参加的活动上，因为它们会给我们带来乐趣，并在⼀定程度上缓解学习压⼒。

第三,我们也可以参加⼀些俱乐部，在那⾥可以遇到志同遣合的⼈,并会以1种直接对我们的学业有利的⽅式提升我们的能⼒。

总⽽⾔之，只有通过更⾼效地学习和更合理地安排业余活动,我们才能获得学业与课外活动之间的真正平衡。

主题词汇excessive 过度的in hot water 陷⼊困境under the spotlight 备受关注disapprove of 不赞同for the sake of...为了..............not to mention..,更不⽤说...............trigger 引发transform...to...把..............转换成.........pave the way for...为..............铺平道路Part HI Reading ComprehensionSection A在我曾写过的可能最为疯狂的新闻报道中，我曾报道过科学家在⽜屁股上画眼睛的实验，这是牲畜保护⽅⾯所取得的(26)进步。

2018年上半年中小学教师资格考试英语学科知识与教学能力试题(高级中学)(精选)

2018年上半年中小学教师资格考试英语学科知识与教学能力试题(高级中学)(精选)一、单项选择题(本大题共30小题，每小题2分，共60分)1. The sound of "ch" in "teacher" is__________.A. voiceless, post-alveolar, and affricativeB. voiceless, dental, and fricativeC. voiced, dental, and fricativeD. voiced, post-alveolar, and plosive2. The main difference between/m/,/n/, and/η/lies in__________.A. manner of articulationB. sound durationC. place of articulationD. voicing3. She is __________ , from her recording, the diaries of Simon Forman.A. transcribingB. keepingC. paraphrasingD. recollecting4. Neither the unpleasant experiences nor the bad luck __________ him discouraged.A. have causedB. has causedC. has madeD. have made5. Mr. Joe has worked very hard in the past two years and has paid all his debts__________the last penny.A. byB. toC. untilD. with6. The message came to the villagers __________ the enemy had already fled the village.A. whichB. whoC. thatD. where7. We must improve the farming method __________we may get high yields.A. in caseB. in order thatC. now thatD. even if8.--Do you mind if I smoke here?--__________.A. Yes, I don'tB. Yes, you mayC. No, not at allD. Yes,I won’t9. What is the main rhetoric device used in “The plowman homeward plods his weary way.”?A. Metaphor.B. Metonymy.C. Synecdoche.D.Transferred epithet.10.--A:Let's go to the movie tonight.--B:I'd like to. but I have to study for an exam.In the conversation above, B's decline of the proposal is categorized as a kindof__________.A. illocutionary actB. perlocutionary actC. propositional conditionD. sincerity condition11. Which of the following activities is NOT typical of the Task-Based Language Teaching method?A. Problem-solving activities.B. Opinion exchange activities.C. Information-gap activities.D. Pattern practice activities.12. If a teacher shows students how to do an activity before they start doing it, he/sheis using the technique of__________.A. presentationB. demonstrationC. elicitationD. evaluation13. When a teacher asks students to discuss how a text is organized,he/she is most likely to help them__________.A. evaluate the content of the textB. analyze the structure of the passageC. understand the intention of the writerD. distinguish the facts from the opinions14. Which of the following practices can encourage students to read an article critically?A. Evaluating its point of view.B. Finding out the facts.C. Finding detailed information.D. Doing translation exercises.15. Which of the following is a display question used by teachers in class?A. If you were the girl in the story,would you behave like her?B. Do you like this story Girl the Thumb ,why or why not?C. Do you agree that the girl was a kind-hearted person?D. What happened to the girl at the end of the story?16. Which of the following would a teacher encourage students to do in order to develop their cognitive strategies?A. To make a study plan.B. To summarize a story.C. To read a text aloud.D. To do pattern drills.17. Which of the following exercises would a teacher most probably use if he/she wants to help students de-velop discourse competence?A. Paraphrasing sentences.B. Translating sentences.C. Unscrambling sentences.D. Transforming sentences.18. The advantages of pair and group work include all of the following EXCEPT__________.A. interaction with peersB. variety and dynamismC. an increase in language practiceD. opportunities to guarantee accuracy19. Which of the following should a teacher avoid when his/her focus is on developing students' ability to use words appropriately?A. Teaching both the spoken and written form.B. Teaching words in context and giving examples.C. Presenting the form, meaning, and use of a word.D. Asking students to memorize bilingual word lists.20. Which of the following practices is most likely to encourage students' cooperation in learning?A. Doing a project.B. Having a dictationC. Taking a test.D. Copying a text.阅读Passage 1，完成第21～25小题。

USING VIEWPOINTS, FRAMEWORKS, AND DOMAIN-SPECIFIC LANGUAGES TO ENHANCE SOFTWARE REUSE

USING VIEWPOINTS, FRAMEWORKS, AND DOMAIN-SPECIFIC LANGUAGESTO ENHANCE SOFTWARE REUSESergio Crespo, Marcus Felipe M. C. da Fontoura, andCarlos José P. de LucenaDepartamento de Informática, Pontifícia Universidade Católica do Rio de Janeiro Rua Marquês de São Vicente, 225, 22453-900 Rio de Janeiro, Brazile-mail: [crespo, mafe, lucena]@inf.puc-rio.brSUMMARYCase studies have shown that high levels of software reuse can be achieved through the use of object-oriented frameworks. This paper describes a viewpoint-based design and instantiation method for framework development. This method uses the concept of viewpoints and the hot-spot relation in object-oriented design to guide the designer on the identification of hot-spots in the structure of the framework. Domain-specific languages are used to help the framework instantiation. A method supporting environment is also presented. Software design through the use of this environment appears to be a very successful approach from the point of view of component reuse.KEY WORDS: object-oriented frameworks, viewpoints, domain-specific languages, framework design and instantiation, domain-oriented software development.1. INTRODUCTIONThere are various application areas that are not established yet and for which new ideas and models are presently under development and evaluation. These are domains in which the possibility of rapidly building new applications is essential and strategic from a practical point of view. Examples of application domains that can be classified in this category include Web-based Education, electronic commerce, biology, and financial market. An interesting strategy for developing new applications for these domains is the development of object-oriented application frameworks [10, 13]. Frameworks can reduce the costs of developing applications since it allows designers and implementers to reuse their previous experience with problem solving at the design and code levels. An object-oriented framework captures the common aspects of a family of applications, which can be seen as a domain theory [19].Although object-oriented software development has experienced the benefits of using frameworks, a thorough understanding of how to identify, design, implement, and change them to meet evolving requirement needs is still object of research [24]. Techniques such as design patterns [10, 17], meta-object protocol [15], refactoring [14], and class reorganization [3] have been proposed to support framework development and cope with some of the challenges.Therefore, framework development is very expensive not only because of the intrinsic difficulty related to capturing the domain theory but also because of the lack of appropriate methods and techniques to support framework specification and design.2. FRAMEWORK DESIGN AND INSTANTIATION METHODIn [19] Roberts and Johnson state that “Developing reusable frameworks cannot occur by simply sitting down and thinking about the problem domain. No one has the insight to come up with the proper abstractions.” They propose the development of concrete examples in order to understand the domain. The design strategy presented here is quite similar, analyzing concrete applications as viewpoints [8, 6] of a domain and deriving the final framework from the analysis of these viewpoints.The approach to framework design is based on the idea that any design can be divided into two parts: the kernel sub-system design and the hot-spot sub-system design. The kernel sub-system design is common to all the applications that the framework may generate, and the hot-spot sub-system design describes the different characteristics of each application that can be supported by the framework. The hot-spot sub-system uses the method and the information provided by the kernel sub-system and may extend it.The kernel structure is defined by analyzing the viewpoints design representations to produce a resulting design representation that reflects a structure that is common to all chosen viewpoints. This part of the design approach is based on a domain-dependent semantic analysis of the design diagrams to elicit the common features of the framework design structure.The elements that are not in the kernel are the ones that vary for each application, and depend on the use of the framework. These elements define the framework hot-spots [17, 20] that must be adapted to each related application. A new relationship in object-oriented design, called the hot-spot relationship, has been defined to specify all the hot-spots in the system.The semantics of this new relationship is given by the design patterns essentials [18]. This implies that the hot-spot relationship is in fact a meta-relationship that is implemented through a design pattern that is generated taking into account the hot-spot flexibility requirements. The hot-spot cards guides this generation process, providing a systematic way for generating design patterns based on flexibility properties.The most common way to instantiate a framework is to inherit from some abstract classes defined in the framework hierarchy and write the code that is called by the framework itself. However, it is not always easy to identify which code and where it should be written since frameworks class hierarchies can be very complex, especially for non-expert users.Therefore, the “common” instantiation process is not always the ideal way to describe a particular application. This happens because of several facts:•the language used to build and use the framework is a wide spectrum language, where it is not always easy to express the user intentions;•the complexity of framework class hierarchies and the difficulty of finding the points where the code should be written, that are the framework hot-spots or flexible points.We propose a different instantiation process [2], where a particular application is described through domain-specific languages (DSLs) [12] that are designed precisely for the framework domain. The technique basic idea is to capture domain concepts in DSLs, which will help the framework user to build code in an easier way, without worrying about implementation decisions and remaining focused on the problem domain. The specification written in the DSLs are translated to the framework instantiation code through the use of transformational systems [16, 4].3. SUPPORTING ENVIRONMENTA supporting environment that is used in the design and instantiation phases has been fully implemented (Figure1). The environment helps all the method’ steps:1.Viewpoint definition: the users define the domain relevant viewpoints through the specification of OMTclass diagrams;2.Viewpoint unification: the environment applies the unification rules [9] to generate an abstract frameworkfrom the selected set of viewpoints;3.Flexibility properties definition: flexibility requirements are defined to generate the appropriate designpatterns that will compose the hot-spot sub-system structure;4.DSLs definition: the definition of the syntax (in a BNF like notation) and semantics (through thespecification of transformation rules) of the domain-specific languages used in the framework instantiation process. The Draco-PUC transformational system is used to perform the transformations and generate the framework instantiation code.Through the use of this environment a framework for Web-based education (WBE), called ALADIN, was generated [5]. We used various existing WBE applications as viewpoints and derived the appropriate abstractions through the viewpoint unification process [1]. Two domain-specific languages were defined to instantiate the ALADIN framework: an educational language and a navigational language.So far our studies show that the ALADIN framework can speed-up the development of WBE applications at least by a factor of 3. We are currently working in the electronic commerce domain to improve our investigation on the method (and on its supporting environment) completeness and effectiveness.4. CONCLUSIONSThis paper shows how viewpoints, and particularly, the hot-spot relationship can be used as the main design driving force to reusable framework construction. The method provides mechanisms that help the framework developer in the identification of the kernel structure and the flexible parts.The hot-spot card is a feature that can help us to bridge the gap between frameworks and design patterns, a still challenging issue [18]. The unification step is responsible for harmonically combining the various viewpoints. The use of the hot-spot relationship in this step helps the definition of the framework kernel and its hot-spots, introducing the necessary flexibility requirements.Figure 1. Method supporting environmentAnother important characteristic of the method is that it is a complementary approach that can be combined to other techniques such as refactoring and OOADM. The method support environment presented in Section 3 uses the refactoring algorithms presented in [14] for the viewpoint unification process and the OMT notation for the viewpoint specification.In [9] we present other examples of viewpoint unification and hot-spot instantiation. The method is currently completely formalized [9], based on the Z specification language [21, 22], object calculus [7], and category theory [11]. Through this formalization we could prove some important properties such as loose coupling.In [1, 5] we present a case study for developing a framework for Web-based education. This framework is now fully implemented by the Software Engineering Laboratory, LES, of the Computer Science Department at PUC-Rio, Catholic University. An example of an application generated by this framework is the AulaNet TM environment (http://www.les.inf.puc-rio.br/aulanet)REFERENCES1.P. Alencar, D. Cowan, S. Crespo, M. F. Fontoura, and C. J. Lucena, “Using Viewpoints to Derive aConceptual Model for Web-Based Education Environments”, MCC17/98, Monografias em Ciência da Computação, Departamento de Informática, PUC-Rio, 1998 (also submitted to Journal of Systems and Software).2. C. Braga, M. F. Fontoura, C. J. Lucena, and L. M. Moura, “Using Domain Specific Languages to InstantiateOO Frameworks”, MCC28/98, Monografias em Ciência da Computação, Departamento de Informática, PUC-Rio, 1998 (also submitted to IEE Proceedings – Software Engineering ).3. E. Casais, “An incremental class reorganization approach”, In ECOOP’92 Proceedings, volume 615 ofLecture Notes in Computer Science, pages 114-132, 1992.4.J. Cordy and I. Carmichael, “The TXL Programming Language Syntax and Informal Semantics”, TechnicalReport, Queen’s University at Kinkston, Canada, 1993.5.S. Crespo, M. F. Fontoura, C. J. Lucena, and L. M. Moura, “ALADIN: An Architecture for LearningwareApplications Design and Instantiation”, MCC34/98, Monografias em Ciência da Computação, Departamento de Informática, PUC-Rio, 1998 (also submitted to WWW Journal).6.J. Derrick, H. Bowman, and M. Steen, “Viewpoints and Objects”, Technical Report, Computing Laboratory,University of Kent, Canterbury, UK, 1997.7.J. Fiadeiro and T. Maibaum, “Sometimes ‘Tomorrow’ is ‘Sometime’”, Temporal Logic, volume 827 ofLecture Notes in Artificial Intelligence, pages 48-66, Springer-Verlag, 1994.8. A. Finkelstein and I. Sommerville, “The viwepoints faq” Software Engineering Journal, 11(1):2-4, January1996.9.M. F. Fontoura, E. H. Hermann, and C. J. Lucena, “A Framework Design and Instantiation Method”,MCC35/98, Monografias em Ciência da Computação, Departamento de Informática, PUC-Rio, 1998.10. E. Gamma, R. Helm, R. E. Johnson, and J. Vlissides, “Design Patterns, Elements of Reusable Object-Oriented Software”, Addison-Wesley, 1995.11.R. Goldblatt, “Topoi – The Categorial Analysis of Logic”, North-Holland Publishing Company, 1979.12.P. Hudak, “Building Domain-Specific Embedded Languages”, Computing Surveys, 28A(4), ACM, 1996.13.R. Johnson, “Frameworks = (Components + Patterns)”, Communications of the ACM, Volume 40, Number10, October 1997.14.R. Johnson and W. F. Opdyke, “Refactoring and aggregation”, In Object Technologies for AdvancedSoftware, First JSSST International Symposium, volume 742 of Lecture Notes in Computer Science, pages 264-278, Springer-Verlag, 1993.15.G. Kiczales, J. des Rivieres, and D. G. Bobrow, “The Art of Mataobject Protocol”, MIT Press, 1991.16.J. C. S. P. Leite, M. Sant’anna, and F. G. Freitas, “Draco-PUC: a Technology Assembly for DomainOriented Software Development”; Proceedings of the 3rd IEEE International Conference of Software Reuse, 1994.17.W. Pree, “Design Patterns for Object-Oriented Software Development”, Addison-Wesley, 1995.18.W. Pree, “Framework Patterns”, Sigs Management Briefings, 1996.19. D. Roberts and R. Johnson, “Evolving Frameworks: A Pattern Language for Developing Object-OrientedFrameworks” in “Pattern Languages of Program Design 3”, Addison-Wesley, 1997.20.H. A. Schmid, “Systematic Framework Design by Generalization”, Communications of the ACM, Volume40, Number 10, October 199721.J. M. Spivey, “Understanding Z: A Specification Language and Formal Semantics”, Cambridge UniversityPress, 1988.22.J. M. Spivey, “The Z Notation: A Reference Manual”, Prentice Hall, Hemel Hempstead, 1989.23.W. Turski and T. S. E Maibaum, “The Specification of Computer Programs”, Addison-Wesley PublishingCompany, 1987.24.R. Wirfs-Brock and R. Johnson, “Surveying current research in object-oriented design”, Communications ofthe ACM, 33(9), 1990.。

大学的英语a级考试作文范文

大学的英语a级考试作文范文篇 1Over the years, the college English Class A examination has presented various types of composition topics. One common type is the chart description, where students are required to carefully observe and analyze the data presented in the chart and then describe the trends and patterns accurately. This demands a clear understanding of the chart and the ability to express the information logically! Another type is the opinion discussion. Here, students need to present their own viewpoints on a given topic, supported by solid reasons and examples. Isn't it challenging to form a coherent and persuasive argument? The problem-solving type is also frequent. It requires students to identify the problem, analyze its causes, and propose feasible solutions. How crucial it is to have a systematic thinking approach! In conclusion, these common types of composition topics in the college English Class A examination all test students' language proficiency, logical thinking, and the ability to express themselves clearly. So, we must be well-prepared and equipped with the necessary skills to handle them effectively!篇 2When it comes to the excellent model essays for College English Test Level A, there are several remarkable writing techniques and strategies that can be discovered. Firstly, a reasonable paragraph layout is of utmost significance! A well-structured essay makes it easy for readers to follow the author's train of thought. For instance, an introduction to catch the readers' attention, followed by detailed body paragraphs presenting arguments, and a conclusion to summarize and emphasize the main points. How crucial it is!Secondly, clear logical expression is indispensable. Every sentence andparagraph should be coherently connected, avoiding confusion and ambiguity. Why is this so important? Because it ensures that the message is conveyed accurately and effectively.Last but not least, the appropriate use of vocabulary plays a vital role. Rich and precise words can enhance the expressiveness and vividness of the essay. Isn't it amazing how a single word can make a big difference?In conclusion, mastering these writing skills and strategies is essential for achieving high scores in the College English Test Level A. Let's keep practicing and improving!篇 3Oh dear students! Let's talk about the scoring standards of the College English Class A Examination composition and how to achieve a high score. Firstly, avoiding grammar mistakes is crucial! How many times have we lost marks just because of a simple tense error or a wrong word form? So, always double-check your grammar. Secondly, the content must be substantial. Don't just write a few simple sentences and call it a composition. Provide detailed examples, explanations, and arguments to make your point clear. For instance, if you're writing about a topic like "The Importance of Reading", don't just say "Reading is important", but elaborate on how it enriches our knowledge and broadens our horizons. Moreover, language coherence is essential. Make sure your paragraphs and sentences flow smoothly. Use proper transitional words and phrases like "however", "therefore", "in addition" to connect your ideas. So, dear friends, if we can pay attention to these aspects, avoid grammar mistakes, enrich the content and ensure language coherence, surely we can get a high score in the exam! How exciting it would be to achieve that!篇 4Oh dear friends, let me share with you my precious experiences in preparing for the composition part of the College English Level A Examination! It's truly a challenging but rewarding journey.First and foremost, regular writing practice is indispensable. Set aside some time every day to write on various topics. This helps enhance your language expression and logical thinking. For instance, you could describe your daily life, express your opinions on current events, or imagine a fictional story.Secondly, the skill of reciting model essays is of great significance. By memorizing excellent examples, you can absorb the essence of good writing and internalize the structure and language usage. But remember, don't just copy blindly. Analyze and understand why these essays are outstanding.Also, the flexible application of templates is a key factor. Templates can provide a framework for your writing, but don't let them restrict your creativity. Adapt and modify them according to the specific topic and your own thoughts.Most importantly, persistence and accumulation are the cornerstones of success. Don't expect immediate improvement. Keep practicing, keep learning, and you will surely see remarkable progress in your writing ability. So, dear friends, let's embark on this journey with determination and enthusiasm!篇 5University English Class A Examination essays play a crucial role in our academic journey. But have you ever wondered how they relate to real-life applications? Let's take a look! In the fierce job market, a well-written essay in the exam showcases our language proficiency and logical thinking skills. It can make our resume stand out among countless others and increase our chances of landing that dream job. Forinstance, when writing a cover letter, the ability to organize ideas clearly and express them precisely, which we acquire through exam practice, is invaluable. Moreover, in academic exchanges, whether it's presenting research findings or participating in international conferences, the writing knowledge gained from the exams enables us to communicate effectively with scholars from all over the world. Don't you think it's amazing how what we learn in exams can have such a significant impact on our practical lives? So, let's attach great importance to the practicality of language and make the most of what we gain from these exams!。

上半年《英语知识与教学能力》(高中)试题(附答案)

上半年《英语知识与教学能力》（高中）试题(附答案).第 1 题 (单项选择题)(每题 2.00 分) > 单项选择题 >Neither the unpleasant experiences nor the bad luck __________ himdiscouraged.{A}. have caused{B}. has caused{C}. has made{D}. have made正确答案：C,第 2 题 (单项选择题)(每题 2.00 分) > 单项选择题 >Mr. Joe has worked very hard in the past two years and has paid all his debts__________the last penny.{A}. by{B}. to{C}. until{D}. with正确答案：B,第 3 题 (单项选择题)(每题 2.00 分) > 单项选择题 >The message came to the villagers __________ the enemy had already fledthe village.{A}. which{B}. who{C}. that{D}. where正确答案：C,第 4 题 (单项选择题)(每题 2.00 分) > 单项选择题 >We must improve the farming method __________we may get high yields.{A}. in case{B}. in order that{C}. now that{D}. even if正确答案：B,第 5 题 (单项选择题)(每题 2.00 分) > 单项选择题 >--Do you mind if I smoke here?--__________.{A}. Yes, I don't{B}. Yes, you may{C}. No, not at all{D}. Yes,I won’t正确答案：C,第 6 题 (单项选择题)(每题 2.00 分) > 单项选择题 >She is __________ , from her recording, the diaries of Simon Forman.{A}. transcribing{B}. keeping{C}. paraphrasing{D}. recollecting正确答案：A,第 7 题 (单项选择题)(每题 2.00 分) > 单项选择题 >The main difference between/m/,/n/, and/η/lies in__________. {A}. manner of articulation{B}. sound duration{C}. place of articulation{D}. voicing正确答案：C,第 8 题 (单项选择题)(每题 2.00 分) > 单项选择题 >The sound of\"ch\" in \"teacher\" is__________.{A}. voiceless, post-alveolar, and affricative{B}. voiceless, dental, and fricative{C}. voiced, dental, and fricative{D}. voiced, post-alveolar, and plosive正确答案：A,第 9 题 (解答题)(每题 40.00 分) > 未分类 >设计任务：请阅读下面学生信息和语言素材，设计20分钟英语阅读的教学方案。

考向6 高考阅读体裁篇之新闻报道 (真题+各地名校试题)(练习版)

专题五：高考阅读体裁篇备战2022年高考英语阅读理解专项突破考向6 新闻报道Passage 1 （2021·云南·曲靖一中一模）A spacecraft carrying Nie Haisheng, Liu Boming and Tang Hongbo touched down safely in the Gobi Desert in Inner Mongolia today (Sept. 17) at 1:34 a.m. EDT (1:34 p.m. Beijing time) today, bringing the historic Shenzhou12 mission to an end.Shenzhou 12 launched on June 16 and arrived seven hours later at Tianhe ("Harmony of the Heavens"), the core module of China's Earth-orbiting space station. The Shenzhou 12 crew, commanded by Nie, spent 90 days aboard Tianhe, staying aloft about three times longer than any previous Chinese crewed spaceflight.Shenzhou 12's return to Earth was a multiday affair. The spacecraft detached from Tianhe Wednesday (Sept. 15) at 8:56 p.m. EDT, according to a statement released by the China Manned Space Engineering Office (CMSEO). Shenzhou 12 then performed a rendezvous test with Tianhe, which was complete by 1:38 a.m. EDT Thursday (Sept.16), CMSEO officials said in another update.During their time in orbit, the Shenzhou 12 astronauts snapped some amazing photos of Earth and carried out a variety of scientific experiments. They also performed two spacewalks designed to help get the 54-foot-long (16.6 meters) Tianhe fully up and running and ready for future visits, which will be frequent over the coming months.For example, China is expected to send the robotic Tianzhou 3 cargo spacecraft toward Tianhe around Sept. 20. And the next crewed mission to the module, the six-month-long Shenzhou 13, is apparently scheduled to launch in mid-October. (Exact target dates are hard to come by with Chinese missions, because the nation tends not to announce many details of its spaceflight plans in advance.)1．In which section can we most possibly read this text on a website?A．Geography B．News C．Health D．Environment2．What is the main purpose of the mission to Tianhe?A．To repair the parts that went wrong.B．To carry out two space walks.C．To send the robotic Tianzhou 3 cargo spacecraft.D．To get China's Earth-orbiting space station ready and running.3．The underlined part touched down in the first paragraph probably means ________.A．Landed successfully B．Launched on timeC．Took off on schedule D．updated around the clock4．According to the passage we know EDT is ______________.A．12 hours ahead of Beijing time B．12 hours later than Beijing timeC．8 hours ahead of Greenwich Mean Time D．8 hours later than Greenwich Mean TimePassage 2 （2021·广西·南宁二中模拟预测）The European wood bison population has grown so much as to no longer be considered "Vulnerable" according to the global authority on conservation,the International Union for Conservation of Nature(IUCN),in their latest Red List update.A century ago,only 50 European bison remained on Earth,and they were mostly restricted to nature reserves.“The conservation successes provide living proof that the world can set,and meet, ambitious biodiversity targets,” said Dr. Jane Smart,Global Director of IUCN' s Biodiversity Conservation Group in a statement.Eight of the 47 bison herds have special genes for long-term survival, so scientists need to move animals in and out of herds in order to make healthy genes continue. Establishing greater numbers of separate herds will also help prevent possible losses due to things like diseases or natural disasters.This led to the creation of a project called “Wilder Blean" where Blean Woods in Kent, England,will receive Dutch and Polish bison to create the first wild herd on the island for 6,000 years.English conservationists and wildlife managers are interested in the effects bison have on the landscape. As large grass-eating animals, the constant foraging, digging and breaking they do on the forest floor have been assumed to have positive effects on the ecosystem.Bison kill weak or dead trees by eating their bark or rubbing against them to remove their thick winter fur. This turns the tree into food and habitat for insects, which in turn provide food for birds.In this way they act like forestry experts, and the Kent Wildlife Trust hopes that this significant species will maintain declining populations of plants, birds, insects, and mammals by way of their unique habits.5．What has made the European wood bison grow in large numbers?A．Being restricted to nature reserves. B．Being updated on the latest Red List.C．Being kept under effective conservation. D．Being born with long-term survival genes.6．What does the underlined word “This” in Paragraph 5 refer to?A．Providing living proof. B．Preventing natural disasters.C．Establishing nature reserves. D．Setting up more separate herds.7．What is the attitude of Kent Wildlife Trust towards the project “Wilder Blean”？A．Supportive. B．Conservative. C．Skeptical. D．Objective.8．What is the purpose of this text?A．To introduce the various actions of European wood bison.B．To highlight the importance of setting and meeting targets.C．To report the conservation successes for European wood bison.D．To praise Dr. Jane Smart for his contributions to conservation.Passage 9 （2021·四川南充·模拟预测）The Taliban said on Sunday that the war in Afghanistan has ended and they will soon declare the establishment of the Islamic Emirate of Afghanistan. They will take responsible actions to ensure the safety of Afghan citizens and foreign missions in Afghanistan.In response, Foreign Ministry spokesperson Hua Chunying said the situation in Afghanistan has undergone major changes and China respects the wishes and choices of the Afghan people.China expects the Taliban to fulfill its commitment to ensure a smooth transition (过渡) of the situation in Afghanistan, keep at bay all kinds of terrorism and criminal acts, keep the Afghan people away from wars and rebuild their beautiful homeland, she said.In response to a question on whether China has contact with the Taliban and recognizes the Taliban regime (政权), Hua said China has maintained contact with the Afghan Taliban on the basis of fully respecting Afghan national sovereignty (主权) and the will of all factions in the country, and has always played a constructive role in promoting the political settlement of the Afghan issue.On July 28, Chinese State Councilor and Foreign Minister Wang Yi met in Tianjin with Baradar, political chief of Afghanistan’s Taliban.“We hope the Taliban will unite with all parties and ethnic groups in Afghanistan to establish a broad andinclusive political structure that suits its own national conditions to lay the foundation for realizing a lasting peace in Afghanistan,” she added.On many occasions, the Taliban has expressed the hope of developing sound relations with China, saying they look forward to China’s participation in the reconstruction and development of Afghanistan, and that they will never allow any forces to use the Afghan territory to endanger China, according to the spokesperson.She said that China always respects the sovereign independence and territorial integrity (完整) of Afghanistan, never interferes in the internal affairs of Afghanistan, and always pursues a friendly policy toward all the Afghan people.The United States and several European countries are evacuating their embassy staff from the country. In response to the question on whether China has any plans to withdraw its embassy, Hua said the Chinese embassy in Afghanistan is still operating normally, and the Chinese ambassador and embassy staff are still performing their duties.Most of the Chinese citizens in Afghanistan have already returned to China according to arrangements made by the Chinese embassy, but there are still a few people who have chosen to stay there voluntarily. The embassy maintains close contact with them, and will continue to pay close attention to the situation in Afghanistan and provide the necessary services and assistance to all Chinese citizens in Afghanistan, Hua said.9．Which of the following can best acts as the title of the passage?A．Taliban Regime Is Established. B．China’s Response to Afghan Situation.C．Hua’s Attitude towards the Taliban.D．Afghan Relations with China.10．According to Hua Chunying, ________.A．China unconditionally recognizes the Taliban regimeB．China sticks to the settlement of the Afghan issue by forceC．China respects choices of Afghan people and calls for smooth transitionD．China offers congratulations on the establishment of the Islamic Emirate of Afghanistan11．Which of the followin g statements doesn’t agree with what Afghan Taliban claims?A．It hopes that its relations with China goes in harmony.B．It takes China’s safety in Afghanistan seriously.C．It will take actions to realize peace.D．It has united with all parties and ethnic groups in Afghanistan.12．The Chinese embassy ________.A．is always there for Chinese citizens in AfghanistanB．has decided to withdrawC．interferes in the internal affairs of AfghanistanD．urges all Chinese citizens in Afghanistan to return homePassage 4 （2021·河北衡水中学模拟预测）On February 22, 2021, cancer survivor Hayley Areeneaux was selected to be one of four crew members of the SpaceX Inspiration4 —the world’s first civilian astronaut mission. The 29-year-old will make history as the youngest American — and the first with a false limb — to travel to space.Hayley’s space dreams began two decades ago, following a visit to the NASA Johnson Space Center in Houston, Texas. However, the young girl’s dreams were derailed a year later when she was diagnosed with osteosarcoma — a type of bone cancer.Fortunately, the fatal disease had been caught early and the experts at St. Jude’s Children’s Research Hospital in Memphis were able to reduce its spread through chemotherapy and by replacing the diseased bones with metal rods (杆) in her left leg. Arceneaux said she never thought she would be able to go to space. But when the call came “out of the blue” from Jared Isaacman, CEO and founder of Shift4 Payments, asking her if she would like to go to space, she said without hesitation, “Yes, yes, absolutely!”Isaacman had always intended to go to space. Hence when SpaceX announced the world’s first all-commercial astronaut mission, the 37-year-old billionaire, instantly booked the available four seats. The flying enthusiast announced that he would donate three seats to members of the general public. Hayley, the first crew member to be announced, will represent the pillar (支柱) of “hope” — a nod to her survival of cancer and frontline work as a physician at St. Jude. The remaini ng passengers, representing the pillars of “generosity” and “prosperity”, will be chosen randomly to raise $200 million for St. Jude, which treats children at no charge.Before the mission launch later this year, the crew will undergo intense training. The mission, which will orbit Earth every 90 minutes, will be carefully monitored by SpaceX mission control scientists from Earth. Upon the mission’s completion, the Dragon will reenter Earth’s atmosphere for a soft water landing off the coast of Florida. 13．Which of the following is the best title of the passage?A．“The Sky Is Not Even The Limit” For Jared IsaacmanB．Hayley’s Space Dreams Were Derailed By OsteosarcomaC．Cancer Survivor To Become The Youngest American In SpaceD．Hayley Arceneaux Became The Youngest American travelling in Space14．What do you know about Hayley Arceneaux?A．She is a disabled woman. B．She was caught in a storm.C．She is a famous physicist. D．She used to be a fighter pilot.15．What does the underlined phrase “out of the blue” in Pa ragraph 3 mean?A．Sadly. B．Strangely. C．Randomly. D．Suddenly.16．Why would Jared Isaacman donate the last two seats to members of the general public?A．To promote his company’s products B．To raise funds for a cancer hospital.C．To inspire interests in space travel. D．To seek help for disabled children.Passage 5 （2021·福建莆田·二模）Hayley Arceneaux, 29 will be the youngest person to go to space when she joins Inspiralion4, a private mission led and funded by Jared Isaacman, a- billionaire businessman and pilot. The mission which is scheduled to launch in October from Cape Canaveral, Florida, will be the first mission to include non-professional astronauts. For that , the crew are receiving training in areas such as the operations of the spacecraft and the rocket that will launch it, working in microgravity, emergency preparedness and mission simulations (模拟).Arceneaux underwent treatment for bone cancer from the age of ten in St Jude Children's Hospital in Tennessee. She endured a dozen rounds of chemotherapy (化疗) and surgery to replace her left knee and thigh bone with titanium (钛) implants after her diagnosis nearly 20 years ago. She now works at the hospital as a physician's assistant.“Honestly, I'm not nervous at all — I am just so excited," said Arcencaux, "I think having cancer made me tough." Dr. Michael Neel, who operated on Arceneaux, said, “Hayley's story will show people that not even the sky is the limit for what you can do, whether it's in medicine, commerce or life in general.""Right now we are at step zero. The door is closed to persons with disabilities. With this pilot project, we have the ambition to open this door and make a leap, to go from zero to one,"the European Space Agency said. 17．What can we learn about Inspiralion4?A．Arcencaux will command the mission.B．The mission will be launched privately.C．The crew prepare themselves in many areas.D．The mission includes no professional astronauts.18．What can people get from Hayley's story according to Dr. Michael Neel?A．Confidence. B．Honesty. C．Ambition. D．Toughness.19．What does “the door” in the last paragraph refer to?A．A leap. B．A step. C．A solution. D．A chance.20．What is the text mainly about?A．Inspiration4 is to be launched in October from Cape Canaveral, Florida：B．A cancer survivor is chosen as the youngest person to travel to space.C．The ESA promises to employ professional astronauts with disabilities.D．Jared Isaaeman funds a private spacecraft to travel in space.Passage 6 （2021·山东·泰安一中二模）The future of space exploration may depend on an art form from the past: origami (折纸艺术), the ancient art of paper folding.Researchers from Washington State University (WSU), US, have used origami to possibly solve the problem of storing and moving fuel to rocket engines, a key challenge in sp ace travel, according to Newswise. They’ve developed a foldable plastic fuel “bladder (囊状物)” resistant to super cold temperatures, which could be used to store and pump fuel in spacecrafts of the future. Their findings have recently been published in the journal Cryogenics.“Folks have been trying to make bags for rocket fuel for a long time,” said Jake Leachman, one of the lead researchers. “We currently don’t do large, long-duration trips because we can’t store fuel long enough in space.”Meanwhile, NASA is also looking to paper folding to help observe distant planets. The agency is currently developing Starshade, a foldable, sunflower-shaped piece of hardware that would help block starlight and enable telescopes to view distant objects more clearly in space.“A huge part of my job is looking at something on paper and asking, ‘Can we fly this?’” Manan Arya, a technologist in California, said. “Once I realized this is how you fold spacecraft structures, I became interested in origami. I realized I was good a t it and enjoyed it. Now, I fold constantly. ”Using origami for space purposes isn’t new, however. Solar arrays (太阳能阵列), experimental wings for space shuttle programs and an inflatable (可充气的) satellite were also inspired by origami in both past and present space projects.“With most origami, the magic comes from the folding,” Robert Salazar, who helped design the Starshade and now works on the Transformers project. said in a statement. “There are so many patterns to still be explored.”21．Which can be the suitable title for the text?A．Folding into space.B．The art of paper folding.C．Space exploration.D．The origami-inspired projects.22．How could the“bladder”help in future missions?A．To protect spacecrafts from extreme weather.B．To be used to store and supply fuel in spacecrafts.C．To help rocket engines cut energy consumption.D．To be used to improve energy efficiency.23．What can we know about NASA’s Starshade?A．It can be used to get telescopes closer to stars.B．It can enlarge the view of telescopes in space.C．It can absorb a star’s light before it enters telescopes.D．It can help telescopes get clearer pictures of objects in space.24．What is this text?A．A travel journal. B．A digest.C．A science report. D．An advertisement.Passage 7 （2021·湖北武昌·模拟预测）Facebook is to allow users to clean up their profiles by hiding posts and photographs dating from when they were teenagers or at university in fears it could hinder their future job prospects. It said it had added the feature because “we know things change in people's lives” and that it wished to make it easier for people to “accurately reflect” who they were in the present. It said the public would be able to use the “Manage Activity” tool to searchtheir posts by year or person, and delete or save those posts in bulk.If users save posts, they will not just be hidden from timelines, as they are with the current "Hide" feature, but from across Facebook as a whole, regardless of where it was posted or who was tagged in it. Such tools could prove useful to those looking to clean up their social media presence ahead of job interviews by making it impossible to find old posts of parties, nights out or fancy dress that could show them in a negative light.However, the move may cause some concern that Facebook is allowing people to whitewash their history, making it more difficult for people to search through posts for evidence of damaging comments.Over the past few years, it has become relatively easy to search through old posts, with the company in 2015 intro ducing a new indexing tool, by which users could search for terms such as “posts about drunk'' and bring up lists of someone's historic posts. This has led to revelations over a number of high-profile figures, who have faced criticism over comments they had made on Facebook in the past.In November, Conservative election candidate Antony Calvert stepped down from campaigning in Wakefield after historic Facebook posts emerged from 2010 and 2011 in which he made racist and sexist remarks. Mr. Calvert, who had once referred to the capital as “Londonistan”, said the entries were more than 10 years old, were not meant to be taken seriously and did not represent his views.25．What docs Facebook allow people to do?A．Hide negative files. B．Whitewash their work.C．Delete new features. D．Search historic posts.26．What's the purpose of Facebook's move?A．To spread a new indexing tool. B．To ensure a bright future.C．To respect high-profile figures. D．To focus on present conduct.27．What does the underlined “hinder” in p aragraph 1 mean?A．Raise. B．Adjust. C．Destroy. D．Interrupt.28．What's the author's attitude towards the move of Facebook?A．Uncertain. B．Understandable. C．Doubtful. D．Objective.Passage 8 （2021·广东·华南师大附中三模）An international team has identified two areas in China where the scale of carbon dioxide absorption by new forests has been underestimated. Taken together, these areas account for a little over 35% of China's entire landcarbon “sink”, the group says.The two previously under-appreciated carbon sink areas are centred on China's southwest, in Yunnan, Guizhou and Guangxi; and its northeast, particularly Heilongjiang and Jilin provinces.These provinces have established a pattern of rapid afforestation of progressively larger regions, with provincial forest areas increasing by between 0.04 million and 0.44 million hectares per year over the past 10 to 15 years.“Bold scientific statements must be supported by massive amounts of evidence and this is what we have done in this study.” Professor Paul Palmer, a co-author from Edinburgh University told the BBC．“We have collected together a range of ground-based and satellite data-driven evidence to form a consistent and robust narrative about the Chinese carbon cycle.”China's increasing leafiness has been evident for some time. Billions of trees have been planted in recent decades, to deal with desertification and soil loss, and to establish vibrant timber and paper industries.Data from NASA Earth satellites shows that human activity in China and India dominate this greening of the planet, thanks to tree planting and agriculture. Satellite data (2000—2017) reveal a greening pattern that is strikingly remarkable in China and India and overlaps with croplands world-wide.China alone accounts for 25% of the global net increase in leaf area with only 6.6% of global vegetated area. 29．According to the passage, which of the following is true about the two newly-identified areas?A．They are based on Southeast and Northwest China.B．Their forests have absorbed over 35% of China’s carbon dioxide.C．They take up over one third of China’s entire land carbon sink areas.D．Their forest areas have increased from 0.04 to 0.44 million hectares per year.30．China has planted more trees in recent decades in order to _________.A．keep the soil fertile B．set up more factoriesC．turn the deserts into green land D．prevent useful land from changing into desert31．The passage is most probably taken from _________.A．a science fiction B．a news website C．an academic report D．a travelling brochure32．Which of the following may be the best title for the passage?A．Carbon Sink Areas in China B．China Aims High in AfforestationC．China and India Lead the Way in Greening D．China's Forest Carbon Absorption UnderestimatedPassage 9 （2021·江苏省如皋中学三模）Elon Musk and his electric car company Tesla have a large following in China－the world’s largest vehicle market－much to the envy of rivals.However, a number of potential customers are deciding against placing orders and some owners are refusing to drive their Teslas to protest the way a customer who complained about an alleged brake failure was treated at the Shanghai auto show.On April 19, the opening day of the show, which is held every two years, a woman got on top of a Tesla Model 3 car and shouted that the brakes did not work. She was quickly dragged away by security guards, who attempted to hide her from visitors with open umbrellas. Footage of the incident taken by onlookers generated more than 150 million views on Sina Weibo within hours.The protester, who was detained by police for disturbing public order, owns a Tesla Model 3 in Henan province, and her father was involved in a traffic accident in February while driving the car. The woman claimed that the crash was caused by a technical problem with the car, but Tesla insisted the accident was due to excessive speed.Soon after the protest, Grace Tao, a Tesla vice-president, told reporters: “There is no possibility Tesla will compromise ... I think she (the protester) is quite professional ... She has contributed to most of the negative news about Tesla recently.” Faced with mounting pressure, the company softened its stance, issuing a series of late-night statements. On April 20, it put out an apology and said it was carrying out a “self-inspection”. Next day, it said it was “working with regulators for investigation”.On Thursday, Tesla disclosed data about the vehicle that crashed, generated before the accident. The data have not been independently verified. Events took another turn three days later, when the woman protester, surnamed Zhang, was released from detention.In a news analysis, Reuters said Tesla defies industry convention, as it is based on a corporate culture that rarely admits mistakes. The company has long been accused by customers of responding in an irresponsible manner to complaints about incidents such as battery fires, unexpected acceleration and failure to provide software updates.Only two months ago, Tesla promised to “strictly abide by Chinese laws and regulations and always respect consumer rights “after the State Administration for Market Regulation urged it to heed consumer complaints”. 33．The woman got on top of a Tesla Model 3 car on April 19 to______.A．protest the way a customer complaining about the brake failureB．go against placing orders and refuse to drive her Tesla laterC．claim that her father was involved in a traffic accident with his TeslaD．inform the public that the crash was caused by a technical problem34．Security guards attempted to hide her from visitors with open umbrellas, because______.A．she disturbed the public orderB．she shouted to make herself heardC．they worried about the negative impact on TeslaD．they insisted the accident was due to excessive speed35．Why did Grace Tao mention that the protester was quite professional?A．Because he suspected that someone may plot it intentionally.B．Because he wanted to say he was unsatisfied with the behavior.C．Because he questioned about the protester’s profession about the car.D．Because he felt annoyed with the negative news caused by the action.36．What’s the main point Reuters tried to make in the second-to-last paragraph?A．Tesla observed Chinese laws and regulations.B．Tesla never admitted mistakes at all events.C．Tesla unreasonably defied industry convention.D．Tesla was negatively faced with many problems.Passage 10 （2021·上海中学一模）China's digital economy is expected to provide a strong boost to global economic recovery, but more efforts should be made to bridge the digital divide and promote data flow, said industry experts and top company officials on Friday.“China’s digital economy, which is indeed in the fast lane, has become a new growth driver of the country’s economic growth amid the COVID-19 pandemic. It has and will play an important role in driving economic recovery globally,” said Gong Ke, president of the World Federation of Engineering Organizations and executive director of the Chinese Institute for the New Generation Artificial Intelligence Development strategies.“While data is an i mportant factor of digital economy, more effort should be made to bridge the digital divideto benefit more user groups. To be specific, we need to improve infrastructure (基础设施) construction and the sharing of computing power from leading companies to smal ler ones,” Gong said.He made the remarks at a sub-forum of the fourth Hongqiao International Economic Forum during the ongoing China International Import Expo in Shanghai.Liu Jun, president of Bank of Communications, said that a winner-takes-all phenomenon is happening during the development of the platform-based economy because the country’s digital economy has developed at an unparalleled speed with insufficient supervision over the past decade.“Therefore, it is necessary to break down the existing inf ormation barriers to promote the free flow of data. The value of data cannot be maximized if a certain company uses it exclusively. Data from various departments, fields and industries must be fully combined and correlated,” Liu said.China’s digital econo my reached $5.4 trillion last year in terms of market size, which grew 9.6 percentyear-on-year, the fastest worldwide, said the China Academy of Information and Communications Technology a government think tank.Such rapid development of the digital economy has attracted companies from abroad to participate. They are also expected to explore more new opportunities in the Chinese market.To embrace the trend, Omron Healthcare said it will leverage its technological competence to develop more digital innovations for the Chinese market.The Japanese industrial automation giant displayed a series of digitalized products, including smart healthcare management terminals and glucose (葡萄糖) meters at the ongoing expo.“The rapid growth of Chinas trade, including dig ital trade, has produced a strong spillover effect for the world and it will enable China’s economy to maintain a long-term positive trend and thus make a contribution to global economic growth, said Zhao Yao, general manager of Omron Healthcare China.The CAICT report also pointed out that China and the United States are leading global development of the digital economy. The two economies also ranked first and second in terms of the market size of digital economy last year.37．According to what Gong Ke said we may learn that ________.A．China’s digital economy takes full advantage of the COVID-19 pandemic.B．Global economic recovery will benefit from China’s digital economy the most.C．Despite covid-19 China 's digital economy pushes global economic growth ahead.。

(2024版)2024年智慧树知道网课《英语教学论》课后章节测试满分答案

可编辑修改精选全文完整版绪论单元测试1【判断题】 (2分)英语学科教学论，是介绍英语知识的一门课。

A.对B.错2【判断题】 (2分)英语学科教学论，是一门介绍如何教英语的课。

A.对B.错3【判断题】 (2分)关于教英语，需要了解相关的语言和语言学习的理论。

A.错B.对4【判断题】 (2分)关于教英语，还需要了解相关的教学方法、了解课堂管理的内容、学习教学设计的理念等。

A.错B.对5【判断题】 (2分)听说读写看的教学，是关于语言技能的教学。

A.错B.对第一章测试1【单选题】 (2分)Which is not the view of language? ( )A.Interactional ViewB.Structural ViewC.Functional ViewD.Constructive View2【单选题】 (2分)Which is not the view of language Learning? ( )A.Behaviorist TheoryB.Cognitive TheoryC.Schema TheoryD.Socio-constructive Theory3【单选题】 (2分)Which is from social-constructivist theory?A.stimulusB.ZPDC.reinforcementD.automatic response4【多选题】 (2分)For new language learning, the aspects that students need to do with are ( )A.Understand the formB.Understand the meaningC.Go abroad for studyingD.Practice the language5【多选题】 (2分)Which belong to process-oriented theory? ( )A.Socio-constructivist TheoryB.Schema TheoryC.Behaviorist TheoryD.Cognitive Theory6【多选题】 (2分)Which belong to condition-oriented theory? ( )A.Constructivist TheoryB.Behaviorist TheoryC.Socio-constructivist TheoryD.Cognitive Theory7【判断题】 (2分)The structural view of language is that language is a system of structurally related ele ments for the transmission of meaning. （）A.错B.对8【判断题】 (2分)The functional view only sees language as a means for doing things. ( )A.对B.错9【判断题】 (2分)For behaviorist theory, mistakes should be immediately corrected, and the correction s hould be immediately praised. ( )A.对B.错10【判断题】 (2分)Learning should be achieved via the dynamic interaction between the teacher and th e learner and between learners. ( )A.错B.对第三章测试1【判断题】 (2分)Teacher Talk Time means teacher should talk more in class and do not leave silence g ap in class. ( )A.对B.错2【判断题】 (2分)Remembering and understanding belong to the higher order thinking ability. ( )A.对B.错3【单选题】 (2分)Which one does not belong to the Bloom’s Taxonomy (2001)? ( )A.ApplyingB.AnalyzingC.RememberingD.Summarizing4【单选题】 (2分)For cognitive level of evaluating, the teacher may ask students the question like ( ).A.What is the relationship between A and B?B.How would you use this?C.Which is more interesting?D.What is the main idea of this paragraph?5【单选题】 (2分)For cognitive level of analyzing, the teacher may ask students the question like ( ).A.Which is more interesting, A or B?B.Can you compare A and B?C.Is there a better solution to this?D.What is an alternative method for this?6【多选题】 (2分)Which belong to teacher’s role? ( )A.controllerB.assessorC.prompterD.organizer7【多选题】 (2分)Teachers as facilitators means ( ).A.to guide them in planning and assessing their own learningB.to use various strategies to motivate learnersC.to develop their learning strategiesD.to create a positive learning environment8【多选题】 (2分)What are the two things that the teacher does as an assessor? ( )A.organizing feedbackB.controlling the paceC.correcting mistakesD.making research on student’s performance9【判断题】 (2分)Even the clearest instructions can be hard to grasp so, after you've given them, it's wo rth checking that they have been understood. ( )A.对B.错10【判断题】 (2分)Allow learners in class the time and the quiet they need, because they need time to thi nk, to prepare what they are going to say and how they are going to say it. ( )A.对B.错第四章测试1【单选题】 (2分)For WHERETO teaching design principle, W refers to ( ).A.allow students to evaluate their work and its implication’sB.be tailored (personalized) to the different needs, interests, and abilities of learnersC.equip students, help them experience the key ideas and explore the issuesD.help the students know where the unit is going and what is expected2【单选题】 (2分)For WHERETO teaching design principle, R refers to ( ).A.help the students know where the unit is going and what is expectedB.allow students to evaluate their work and its implication’sC.equip students, help them experience the key ideas and explore the issuesD.provide opportunities to rethink and revise their understandings and work3【单选题】 (2分)Which belongs to teaching design principle? ( )A.WHERETOB.ESAC.SMARTD.ABCD4【多选题】 (2分)What does WHERETO teaching design principle refer? ( )A.equip students, help them experience the key ideas and explore the issuesB.help the students know where the unit is going and what is expectedC.allow students to evaluate their work and its implication’sD.hook all students and hold their interest5【多选题】 (2分)What are the frequently applied teaching models? ( )A.WHERETO ModelB.Backward Design ModelC.ASSURE ModelD.ADDIE Model6【多选题】 (2分)What are the four elements of articulating learning objectives? ( )A.ConditionB.AudienceC.DegreeD.Behavior7【判断题】 (2分)Develop student’s reading skills. This learning objective is appropriately presented. ( )A.错B.8【判断题】 (2分)SMART is the method for articulating learning objectives. ( )A.对B.错9【判断题】 (2分)Activation of prior knowledge means activating cognitive structures that relate to the to pics and tasks to be studied and completed. ( )A.错B.对10【判断题】 (2分)The purpose of teaching design is to implement teaching effectively. ( )A.B.对第五章测试1【单选题】 (2分)What is used to express meanings in many subtle ways such as surprise, complaint, s arcasm, delighted, threats, etc.? ( )A.PronunciationB.morphologyC.PhonologyD.Intonation2【单选题】 (2分)What is the best age to start learning to read through phonics? ( )A.4-6B.C.1-2D.2-33【单选题】 (2分)After learning the individual letters’ sounds, it is natural to learn the sounds o f ? ( )A.consonant lettersB.blending lettersC.all of the aboveD.vowel letters4【多选题】 (2分)Which generally should be pronounced as weak form while reading aloud? ( )A.Auxiliary wordB.C.VerbD.Preposition5【多选题】 (2分)Phonics is a method for teaching and of the English language by develo ping learners' phonemic awareness—the ability to hear, identify, and manipulate phon emes—in order to teach the correspondence between these sounds and the spelling p atterns that represent them. ( )A.speakingB.writingC.listeningD.reading6【多选题】 (2分)Sound /k/ can be spelled as ? ( )A.kB.chC.ckD.c7【判断题】 (2分)Research has shown that children who have not developed reading skills by second gr ade, will experience an overall delay in learning throughout their school life. ( )A.对B.错8【判断题】 (2分)Understanding phonics will also help children know which letters to use when they ar e writing words. ( )A.对B.错9【判断题】 (2分)A lot of people start the journey of teaching kids phonics through the traditional ways, l ike teaching them to read, and this is the best way to follow. ( )A.错B.对10【判断题】 (2分)Written language can be compared to a code, so knowing the sounds of individual lett ers and how those letters sound when they’re combined will help children code word s as they read. ( )A.对B.错第六章测试1【单选题】 (2分)What does the first aspect of vocabulary learning involve according to Hedge (200 0)? ( )A.The sense relations among words.B.Connotative meaning.C.Denotative meaning.D.Denotative and connotative meaning.2【单选题】 (2分)Which is not the appropriate way of consolidating vocabulary? ( )A.Play a game.B.Categories.C.Spot the difference.D.Guessing.3【单选题】 (2分)Which is not a collocation? ( )A.See a movie.B.Watch a play.C.Movie.D.Look at a picture.4【多选题】 (2分)According to Hedge (2000), what does the second aspect of vocabulary learning invol ve? ( )A.Spelling and PronunciationB.Collocations.C.Synonyms, antonyms and hyponyms.D.Receptive and productive vocabulary.5【多选题】 (2分)What does knowing a word involve? ( )A.How and when to use it to express the intended meaning.B.Its meaning.C.Its spelling and grammatical properties.D.Its pronunciation and stress.6【多选题】 (2分)Which belong to vocabulary learning strategies? ( )A.Use a dictionary.B.Review regularly.C.Guessing from context.D.Presenting vocabulary.7【判断题】 (2分)Denotative meaning refers to those words that we use to label things as regards real o bjects, such as a name or a sign, etc. in the physical world. ( )A.错B.对8【判断题】 (2分)Antonyms refer to the sameness or close similarity of meaning or we can say that wor ds are close in meaning. ( )A.对B.错9【判断题】 (2分)Receptive/passive vocabulary refers to words that one is able to recognize and compr ehend in reading or listening but unable to use automatically in speaking or writing. ( )A.错B.对10【判断题】 (2分)Collocations refer to words that co-occur with high frequency and have been accepte d as ways for the use of words. ( )A.对B.错第七章测试1【单选题】 (2分)Deductive reasoning is essentially a approach which moves from the more gen eral to the more specific. ( )A.gameB.down-topC.traditionalD.top-down2【单选题】 (2分)is an approach that removes you, the teacher, from the main role of “explainer” and ex tends to the students the opportunity to question and discover the target grammar. ( )A.The guided discovery methodB.Mechanical practiceC.Deductive methodD.Inductive method3【单选题】 (2分)usually comes after mechanical practice. ( )A.The guided discovery methodB.Meaningful practiceC.Deductive methodD.Inductive method4【多选题】 (2分)Although a little less effective than inductive teaching, benefits to the deductive approa ch are: ( )A.It encourages faster learning of material and understand the meaningB.Time in the classroom is spent only on the language principle.C.Most material can be easily taught this way.D.Students can have lots of interaction with others in a meaningful context.5【多选题】 (2分)Although inductive teaching takes longer than deductive, many educators agree it i s a very efficient method in the long run. Benefits include: ( )A.Students rely on their critical thinking to figure out the language.B.Students can gain deeper understanding of the language.C.Students can get more interaction and participation among each other.D.No material can be easily taught this way.6【多选题】 (2分)Using prompts has proved to be an effective way of grammar practice. The prompts ca n be: ( )A.picturesB.tablesC.key wordsD.mines7【判断题】 (2分)The deductive and inductive teaching methods can be illustrated in this picture. ( )A.对B.错8【判断题】 (2分)That the students are asked to produce language based on pictures and key phrase s provided by the teacher is using chained phrases for storytelling. ( )A.对B.错9【判断题】 (2分)In mechanical practice the focus is on the production, comprehension or exchange o f meaning through the students “keep an eye on” the way newly learned structures ar e used in the process. ( )A.对B.错10【判断题】 (2分)Grammar practice is usually divided into two categories, mechanical practice and mea ningful practice. ( )A.错B.对第八章测试1【单选题】 (2分)Which is not involved in bottom-up processing while listening? ( )A.Recognizing phrases.B.Referring meaning from background knowledge.C.Recognizing structures.D.Recognizing sounds of words.2【单选题】 (2分)Which is not the stage of listening teaching? ( )A.While-listening.B.Predicting.C.Pre-listening.D.Post-listening.3【单选题】 (2分)Which is not the main listening difficulty of learners? ( )A.Quickly forget what is heard.B.Neglect the next part when thinking about meaning.C.Able to form a mental representation from words heard.D.Do not recognize words they know.4【多选题】 (2分)What are two models that are frequently used to describe different processes of listeni ng? ( )A.Top-up model.B.Top-down model.C.Bottom-up model.D.Bottom-down model.5【多选题】 (2分)Which belong to principles for teaching listening? ( )A.Focus on process.B.Combine listening with other skills.C.Focus on the comprehension of meaning.D.Grade difficulty level appropriately.6【多选题】 (2分)What are three main categories that affect the difficulty level of listening tasks accordin g to Anderson and lynch (1988)? ( )A.Context in which the listening occurs.B.Bottom-up and top-down approaches.C.Type of language used.D.Task or purpose in listening.7【判断题】 (2分)Bottom-up and top-down these two processes are mutually dependent. ( ）A.对B.错8【判断题】 (2分)It is important to develop listening skills together with other skills because ordinarily list ening is not an isolated skill. ( )A.错B.对9【判断题】 (2分)Multiple-choice tests play a decisive role in helping students develop good listening ha bits and strategies. ( )A.错B.对10【判断题】 (2分)In the top-down model, listening for gist and making use of the contextual clues and ba ckground knowledge to construct meaning are emphasized. ( )A.对B.错第九章测试1【单选题】 (2分)Which is not the principle for teaching speaking? ( )A.Maximizing meaning interactions.B.Problem-solving activities.C.Personalizing practice.D.Contextualizing practice.2【单选题】 (2分)Which practice is not structure-based with a focus on forms? ( )A.Grammar learning.B.Syntax learning.C.Providing sufficient opportunities for students to develop fluency.D.Vocabulary learning.3【单选题】 (2分)Which of the following activities is often used to develop students’ speaking accurac y? ( )A.Acting out the dialogue in the text.B.Having discussions in groups.C.Describing people in pair.D.Identifying and correcting oral mistakes.4【多选题】 (2分)Like all the other skills, what strategies does speaking involve?( )A.Turn taking.B.Asking for clarification.C.Initiating a conversation.D.Ending a conversation.5【多选题】 (2分)Which belong to common features of spoken language according to Bygate (1987)? ( )A.Using devices such as fillers, hesitation device to give time to think before speaking.B.Taking short cuts, e.g. incomplete sentences.C.Using less complex syntax.D.Using fixed conventional phrases or chunks.6【多选题】 (2分)Which belong to typical speaking tasks? ( )A.Problem-solving activities.B.Dialogues and role-plays.C.Doing translation exercises.D.Information-gap activities.7【判断题】 (2分)Maintaining a balance between accuracy-based and fluency-based practices is essenti al in teaching speaking.( )A.对B.错8【判断题】 (2分)Speaking is the skill that the students will be judged upon most in simulated situation s. ( )A.错B.对9【判断题】 (2分)Problem-solving activities tend to be productive because there is a clear objective to b e reached or problem to be solved and require a higher level of language proficienc y. ( )A.错B.对10【判断题】 (2分)Designing speaking activities that maximize students’ opportunity to speak is one of th e central tasks for language teachers. ( )A.错B.对第十章测试1【单选题】 (2分)Which is not the teaching step of viewing teaching? ( )A.What message does the image transmit?B.What do you feel?C.What can you touch?D.What can you see?2【单选题】 (2分)Which is not the three-dimension paradigm by Serafini (2014)? ( )A.StructuralB.IntellectualC.IdeologicalD.Perceptual3【单选题】 (2分)What is the definition of Visual literacy? ( )A.With technology, images and visual presentations are flourishing more than ever.B.It means student's ability to “use, interpret, analyze, and think critically about visual images and the signi ficance of what they are seeing”.C.This involves exploring how ideas and emotions are expressed and the use of lighting to create an emoti onal or physiological point.D.Visual literacy is based on the idea that can be "read" and that meaning can be through a process of re ading.4【多选题】 (2分)Which are the teaching steps of viewing teaching? ( )A.What can you touch?B.What is the image trying to tell us?C.What can you see?D.What do you feel?5【多选题】 (2分)What are the pedagogical questions that the teacher can use in class to develop learn ers’ visual literacy? ( )A.How could you change/improve this image?B.What more can we find out?C.What does this image say to us?D.Where has this image come from?6【多选题】 (2分)What can be used as visual literacy clues to facilitate identifying the visual products? ( )A.ColorB.ShapeC.GestureD.Lighting7【判断题】 (2分)We need to consider the active viewer as well and engage the students' creative or cur ative responses to the image. ( )A.错B.对8【判断题】 (2分)One of the most effective ways to encourage information to make that important jump f rom the limited short-term memory to the more powerful long-term memory is to pair te xt with images. ( )A.错B.对9【判断题】 (2分)As these students travel on their road to fluency in English, images can provide an eff ective bridge in that learning process. ( )A.错B.对10【判断题】 (2分)Information presented visually is processed extremely quickly by the brain. ( )A.对B.错第十一章测试1【单选题】 (2分)When expectations are set up, what kind of process of reading is ready to begin? ( )A.ForcedB.PassiveC.NegativeD.Active2【单选题】 (2分)What does bottom-up model mean? ( )A.The teacher should teach the background knowledge first, so that students equipped with such knowled ge will be able to guess meaning from the printed page.B.The teacher teaches reading by introducing vocabulary and new words first and then going over the tex t sentence by sentence.C.None of the above.D.Not only linguistic knowledge but also background knowledge is involved in reading.3【单选题】 (2分)Which is not the reading skill that the learners should be developed in reading clas s? ( )A.Making prediction based on vocabulary or titleB.Guessing the word’s meaningC.Cooperating with othersD.Making inference4【多选题】 (2分)What are the principles for reading teaching? ( )A.Prediction is a major factor in reading.B.Students should be encouraged to respond to the content of a reading text, not just to the language.C.Students need to be engaged with what they are reading.D.Good teachers exploit reading texts to the full.5【多选题】 (2分)What are the models for reading teaching? ( )A.Top-down ModelB.Discovery ModelC.Interactive ModelD.Bottom-up Model6【多选题】 (2分)Find out the reading skills that the learners should be cultivated in reading class. ( )A.Making inferenceB.SkimmingC.ScanningD.Guessing the word’s meaning7【判断题】 (2分)As with everything else in lessons, students who are not engaged with the reading tex t will not actively interested in what they are doing. ( )A.错B.对8【判断题】 (2分)In the Top-down Model, the teacher teaches reading by introducing vocabulary and ne w words first and then going over the text sentence by sentence. ( )A.错B.对9【判断题】 (2分)According to the Interactive Model of reading, when one is reading, the brain receive s visual information, and at the same time, interprets or reconstructs the meaning tha t the writer had in mind when he wrote the text. ( )A.错B.对10【判断题】 (2分)Reading comprehension involves extracting the relevant information from the text as e fficiently as possible, connecting the information from the written message with one’s o wn knowledge to arrive at an understanding. ( )A.错B.对第十二章测试1【单选题】 (2分)Which will not help teachers motivate students to write? ( )A.Encourage collaborative group writing as well as individual writing.B.Leave students less room for creativity and imagination.C.Make the topic of writing as close as possible to students' life.D.Provide constructive and positive feedback.2【单选题】 (2分)What product-oriented method of teaching writing mean? ( )A.Writing activities should serve to encourage a process of brainstorming, drafting, writing, feedback, revis ing and editing, which proceeds in a cyclical fashion resembling the writing process of a real writer.B.It pays great attention to the accuracy of the final product but ignores the process, which the students g o through to reach the final goal.C.The process approach to writing does not only pay attention to what students do while they are writing, i t also attaches great importance to what they and the teacher do before they start writing and after they f inish writing.D.What really matter is the help that the teacher provides to guide students through the process that they undergo when they are writing.3【单选题】 (2分)What does process approach to writing mean? ( )A.What really matter is the help that the teacher provides to guide students through the process that they undergo when they are writing.B.Encourage feedback both from themselves.C.Do not give students time to discover what they want to say as they write.D.Teaching writing pays great attention to the accuracy of the final product but ignores the process.4【多选题】 (2分)Which principles can help teachers motivate students to write? ( )A.Leave students enough room for creativity and imagination.B.Provide opportunities for students to share their writings.C.Make the topic of writing as close as possible to students' life.D.Encourage collaborative group writing as well as individual writing.5【多选题】 (2分)Which principles will motivate students to write? ( )A.Give students a sense of achievement from time to time.B.Leave students less room for creativity and imagination.C.。

与智能有关的词汇英语作文

In the realm of artificial intelligence,there is a vast array of vocabulary that has emerged to describe the various concepts,technologies,and applications.Here are some key terms and their explanations that are essential for anyone looking to understand or discuss intelligent systems:1.Artificial Intelligence AI:Refers to the simulation of human intelligence in machines that are programmed to think like humans and mimic their actions.2.Machine Learning ML:A subset of AI that allows software applications to become more accurate in predicting outcomes without being explicitly programmed to do so.3.Deep Learning:A subset of machine learning that uses neural networks with many layers to analyze complex patterns in large amounts of data.4.Neural Networks:A series of algorithms modeled loosely after the human brain that are designed to recognize patterns.5.Natural Language Processing NLP:The ability of a computer program to understand, interpret,and generate human language,both spoken and written.6.Cognitive Computing:An AI system that can think like a human,combining data analysis,natural language processing,and machine learning to mimic the way the human brain works.7.Robotics:The branch of technology that deals with the design,construction,operation, and use of robots,often integrated with AI to perform tasks autonomously.8.Expert Systems:AI systems that use accumulated knowledge to solve problems that typically require a human expert.9.Autonomous Systems:Systems that operate independently without the need for direct human supervision or control.10.Predictive Analytics:The use of data,statistical algorithms,and machine learning techniques to identify the likelihood of future outcomes based on historical data.11.Sentiment Analysis:The process of computationally identifying and categorizing opinions expressed in a piece of text to determine the writers attitude towards a particular topic or the overall sentiment of a document.puter Vision:A field of AI that trains computers to interpret and understand the visual world from images or videos.13.Fuzzy Logic:A form of logic that deals with reasoning that is approximate rather than fixed and exact,allowing for more humanlike decisionmaking.14.Genetic Algorithms:A search heuristic that mimics the process of natural selection to generate useful solutions to optimization and search problems.15.Reinforcement Learning:A type of machine learning where an agent learns to behave in an environment by performing actions and seeing the results,with the aim of maximizing some notion of longterm reward.16.Chatbots:AI programs designed to simulate conversation with human users,either via text or voice interactions.17.Virtual Personal Assistants VPAs:Software agents that perform tasks or services for an individual,such as setting reminders,sending messages,or providing information. 18.Smart Home Technology:AIpowered devices and systems that automate and control various aspects of a home,such as lighting,security,and temperature.19.Edge Computing:A method of optimizing cloud computing systems by performing data processing at the edge of the network,closer to the source of data,which can be useful for AI applications requiring realtime processing.20.Quantum Computing:A type of computing that uses quantum bits qubits to perform complex calculations at speeds exponentially faster than classical computers,which could revolutionize AI in the future.Understanding these terms is crucial for anyone interested in the field of AI,as they form the foundation of intelligent systems and their applications in various industries.。

高三英语学术研究方法创新思路单选题30题

高三英语学术研究方法创新思路单选题30题1. In academic research, a hypothesis is a(n) ______ that needs to be tested.A. ideaB. factC. resultD. example答案：A。

本题考查学术研究中“hypothesis（假设）”的概念。

选项A“idea（想法、主意）”符合“hypothesis”需要被测试的特点；选项B“fact（事实）”是已经确定的，无需测试；选项C“result（结果）”是研究得出的，不是先提出的；选项D“example（例子）”与“hypothesis”的概念不符。

2. When conducting research, collecting data is an important step. Which of the following is NOT a common way of collecting data?A. InterviewsB. GuessingC. ObservationsD. Surveys答案：B。

本题考查学术研究中收集数据的常见方法。

选项A“Interviews（访谈）”、选项C“Observations（观察）”和选项D“Surveys 调查）”都是常见的数据收集方式；选项B“Guessing（猜测）”不是科学的收集数据的方法。

3. The purpose of a literature review in academic research is to ______.A. show off one's reading skillsB. summarize existing knowledge on a topicC. copy other people's researchD. make the research longer答案：B。

SLA_期末考试提纲(汇总版)

SLA 期末考试提纲Week 9Chapter 1 Introducing Second Language AcquisitionChapter 2 Foundations of Second Language AcquisitionPART ONE: Definition:1.Second Language Acquisition (SLA): a term that refers both to the study of individuals and groups who arelearning a language subsequent to learning their first one as young children, and to the process of learning that language.2.Formal L2 learning: instructed learning that takes place in classrooms.rmal L2 learning: SLA that takes place in naturalistic contexts.4.First language/native language/mother tongue (L1): A language that is acquired naturally in early childhood,usually because it is the primary language of a child‘s family. A child who grows up in a multilingual setting may have more than one ―first‖ language.5.Second language (L2):: A language that is acquired naturally in early childhood, usually because it is the primarylanguage of a child‘s family. A child who grows up in a multilingual setting may have more than one ―first‖ language.6.Target language: The language that is the aim or goal of learning.7.Foreign language: A second language that is not widely used in the learners‘ immediate social context, but ratherone that might be used for future travel or other cross-cultural communication situations, or one that might be studied be studied as a curricular requirement or elective in school with no immediate or necessary practical application.8.Library language: A second language that functions as a tool for further learning, especially when books andjournals in a desired field of study are not commonly published in the learner‘s L1.9.Auxiliary language: A second language that learners need to know for some official functions in their immediatesociopolitical setting. Or that they will need for purposes of wider communication, although their first language serves most other needs in their lives.10.Linguistic competence: The underlying knowledge that speakers/hearers have of a language. Chomskydistinguishes this from linguistic performance.11.Linguistic performance: The use of language knowledge in actual production.municative competence: A basic tenet (原则、信条、教条) of sociolinguistics defined as ―what a speakerneeds to know to communicate appropriately within a particular language community‖ (Saville-Troike 2003) 13.Pragmatic competence: Knowledge that people must have in order to interpret and convey meaning withincommunicative situations.14.Multilingualism: The ability to use more than one language.15.Monolingualism: The ability to use only one language.16.Simultaneous multilingualism: Ability to use more than one language that were acquired during early childhood.17.Sequential multilingualism: Ability to use one or more languages that were learned after L1 had already beenestablished.18.Innate capacity: A natur al ability, usually referring to children‘s natural ability to learn or acquire language.19.Child grammar: Grammar of children at different maturational levels that is systematic in terms of production andcomprehension.20.Initial state: The starting point for language acquisition; it is thought to include the underlying knowledge aboutlanguage structures and principles that are in learners‘ heads at the very start of L1 or L2 acquisition.21.Intermediate state: It includes the maturational changes which take pla ce in ―child grammar‖, and the L2developmental sequence which is known as learner language.22.Final state: The outcome of L1 and L2 leaning, also known as the stable state of adult grammar.23.Positive transfer: Appropriate incorporation of an L1 structure or rule in L2 structure.24.Negative transfer: Inappropriate influence of an L1 structure or rule on L2 use. Also called interference.25.Poverty-of-the-stimulus: The argument that because language input to children is impoverished and they stillacquire L1, there must be an innate capacity for L1 acquisition.26.Structuralism: The dominant linguistic model of the 1950s, which emphasized the description of different levels ofproduction in speech.27.Phonology: The sound systems of different languages and the study of such systems generally.28.Syntax: The linguistic system of grammatical relationships of words within sentences, such as ordering andagreement.29.Semantics: The linguistic study of meaning.30.Lexicon: The component of language that is concerned with words and their meanings.31.Behaviorism: The most influential cognitive framework applied to language learning in the 1950s. It claims thatlearning is the result of habit formation.32.Audiolingual method: An approach to language teaching that emphasizes repetition and habit formation. Thisapproach was widely practiced in much of the world until at least the 1980s.33.Transformational-Generative Grammar: The first linguistic framework with an internal focus, whichrevolutionized linguistic theory and had profound effect on both the study of first and second languages. Chomsky argued effectively that the behaviorist theory of language acquisition is wrong because it cannot explain the creative aspects of linguistic ability. Instead, humans must have some innate capacity for language.34.Principles and Parameters (model): The internally focused linguistic framework that followed Chomsky‘sTransformational-Generative Grammar. It revised specifications of what constitutes innate capacity to include more abstract notions of general principles and constraints common to human language as part of a Universal Grammar.35.Minimalist program: The internally focused linguistic framework that followed Chomsky‘s Principles andParameters model.This framework adds distinctions between lexical and functional category development, as well as more emphasis on the acquisition of feature specification as a part of lexical knowledge.36.Functionalism: A linguistic framework with an external focus that dates back to the early twentieth century andhas its roots in the Prague School (布拉格学派) of Eastern Europe. It emphasizes the information content of utterances and considers language primarily as a system of communication. Functionalist approaches have largely dominated European study of SLA and are widely followed elsewhere in the world.37.Neurolinguistics: The study of the location and representation of language in the brain, of interest to biologists andpsychologists since the nineteenth century and one of the first fields to influence cognitive perspectives on SLA when systematic study began in 1960s.38.Critical period: The limited number of years during which normal L1 acquisition is possible.39.Critical Period Hypothesis: The claim that children have only a limited number of years during which they canacquire their L1 flawlessly; if they suffered brain damage to the language areas, brain plasticity in childhood would allow other areas of the brain to take over the language functions of the damaged areas, but beyond a certain age, normal language development would not be possible. This concept is commonly extended to SLA as well, in the claim that only children are likely to achieve native or near-native proficiency in L2.rmation processing (IP): A cognitive framework which assumes that SLA (like learning of other complexdomains) proceeds from controlled to automatic processing and involves progressive reorganization of knowledge.41.Connectionism: A cognitive framework for explaining learning processes, beginning in the 1980s and becomingincreasingly influential. It assumes that SLA results from increasing strength of associations between stimuli and responses.42.Variation theory: A microsocial framework applied to SLA that explores systematic differences in learnerproduction which depend on contexts of use.43.Accommodation theory: A framework for study of SLA that is based on the notion that speakers usuallyunconsciously change their pronunciation and even the grammatical complexity of sentences they use to sound more like whomever they are talking to.44.Sociocultural theory (SCT): An approach established by Vygotsky which claims that interaction not onlyfacilitates language learning but is a causative force in acquisition. Further, all of learning is seen as essentially a social process which is grounded in sociocultural settings.45.Ethnography(人种论、民族志) of communication: A framework for analysis of language and its functions thatwas established by Hymes(1966). It relates language use to broader social and cultural contexts, and applies ethnographic methods of data collection and interpretation to study of language acquisition and use.46.Acculturation(文化适应): Learning the culture of the L2 community and adapting to those values and behaviorpatterns.47.Acculturation Model/Theory: Schumann‘s (1978) theory that identifies gro up factors such as identity and statuswhich determine social and psychological distance between learner and target language populations. He claims these influence outcomes of SLA.48.Social psychology: A societal approach in research and theory that allows exploration of issues such as howidentity, status, and values influence L2 outcomes and why. It has disciplinary ties to both psychological and social perspectives.PART TWO: Short & Long answers:Chapter 11.What are the similarities and differences between linguists, psycholinguist, sociolinguists and socialpsycholinguists? P3（1）Linguists emphasize the characteristics of the differences and similarities in the languages that are being learned, and the linguistic competence (underlying knowledge) and linguistic performance (actual production) of learners at various stages of acquisition.（2）Psychologists and psycholinguists emphasize the mental or cognitive processes involved in acquisition, and the representation of languages in the brain.（3）Sociolinguists emphasize variability in learner linguistic performance, and extend the scope of study to communicative competence (underlying knowledge that additionally accounts for language use, or pragmatic competence).（4）Social psychologists emphasize group-related phenomena, such as identity and social motivation, and the interactional and larger social contexts of learning.2.What are the differences between second language, foreign language, library language and auxiliarylanguage? P4（1）A second language is typically an official or societally dominant language needed for education, employment, and other basic purposes. It is often acquired by minority group members or immigrants who speak another language natively. In this more restricted sense, the term is contrasted with other terms in this list.（2）A foreign language is one not widely used in the learners' immediate social context which might be used for future travel or other cross-cultural communication situations, or studied as a curricular requirement or elective in school, but with no immediate or necessary practical application.（3）A library language is one which functions primarily as a tool for future learning through reading, especially when books or journals in a desired field of study are not commonly published in the learners' native tongue.（4）An auxiliary language is one which learners need to know for some official functions in their immediate political setting, or will need for purposes of wider communication, although their first language serves most other needs in their lives.3.Why are some learners more (or less) successful than other? P5The intriguing question of why some L2 learners are more successful than others requires us to unpack the broad label ―learners‖ for some dimensions of disc ussion. Linguistics may distinguish categories of learners defined by the identity and relationship of their L1 and L2; psycholinguists may make distinctions based on individual aptitude for L2 learning, personality factors, types and strength of motivation, and different learning strategies;sociolinguists may distinguish among learners with regard to social, economic, and political differences and learner experiences in negotiated interaction; and social psychologists may categorize learners according to aspects of their group identity and attitudes toward target language speakers or toward L2 learning itself.Chapter21.List at least five possible motivations for learning a second language at an older age. P10The motivation may arise from a variety of conditions, including the following:●Invasion or conquest of one‘s country by speakers of another language;● A need or desire to contact speakers of other languages in economic or other specific domains;●Immigration to a country where use of a language other than one's L1 is required;●Adoption of religious beliefs and practices which involve use of another language;● A need or desire to pursue educational experiences where access requires proficiency in another language;● A desire for occupational or social advancement which is furthered by knowledge of another language;●An interest in knowing more about peoples of other cultures and having access to their technologies orliteratures.2.What are the two main factors that influence the language learning? P13（1）The role of natural ability: Humans are born with a natural ability or innate capacity to learn language.（2）The role of social experience: Not all of L1 acquisition can be attributed to innate ability, for language-specific learning also plays a crucial role. Even if the universal properties of language arepreprogrammed in children, they must learn all of those features which distinguish their L1 from all other possible human languages. Children will never acquire such language-specific knowledge unless that language is used with them and around them, and they will learn to use only the language(s) used around them, no matter what their linguistic heritage. American-born children of Korean or Greek ancestry will never learn the language of their grandparents if only English surrounds them, for instance, and they will find their ancestral language just as hard to learn as any other English speakers do if they attempt to learn it as an adult. Appropriate social experience, including L1 input and interaction, is thus a necessary condition for acquisition.3.What is the initial state of language development for L1 and L2 respectively? P17-18The initial state of L1 learning is composed solely of an innate capacity for language acquisition which may or may not continue to be available for L2, or may be available only in some limited ways. The initial state for L2 learning, on the other hand, has resources of L1 competence, world knowledge, and established skills for interaction, which can be both an asset and an impediment.4.How does intermediate states process? P18-19The cross-linguistic influence, or transfer of prior knowledge from L1 to L2, is one of the processes that is involved in interlanguage development. Two major types of transfer which occur are: (1) positive transfer, when an L1 structure or rule is used in an L2 utterance and that use is appropriate or ―correct‖ in the L2; and (2) negative transfer (or interference), when an L1 structure or rule is used in an L2 utterance and that use is inappropriate and c onsidered an ―error‖.5.What is a necessary condition for language learning (L1 or L2)? P20Language input to the learner is absolutely necessary for either L1 or L2 learning to take place. Children additionally require interaction with other people for L1 learning to occur. It is possible for some individuals to reach a fairly high level of proficiency in L2 even if they have input only from such generally non-reciprocal sources as radio, television, or written text.6.What is a facilitating condition for language learning? P20While L1 learning by children occurs without instruction, and while the rate of L1 development is not significantly influenced by correction of immature forms or by degree of motivation to speak, both rate and ultimate level of development in L2 can be facilitated or inhabited by many social and individual factors, such as(1) feedback, including correction of L2 learners' errors; (2) aptitude, including memory capacity and analyticability; (3) motivation, or need and desire to learn; (4) instruction, or explicit teaching in school settings.7.Give at least 2 reasons that many scientists believe in some innate capacity for language. P21-24The notion that innate linguistic knowledge must underlie language acquisition was prominently espoused by Noam Chomsky. This view has been supported by arguments such as the following:(1)Children‘s knowledge of language goes beyond what could be learned from the input they receive: Childrenoften hear incomplete or ungrammatical utterances along with grammatical input, and yet they are somehow able to filter the language they hear so that the ungrammatical input is not incorporated into their L1 system.Further, children are commonly recipients of simplified input from adults, which does not include data for all of the complexities which are within their linguistic competence. In addition, children hear only a finite subset of possible grammatical sentences, and yet they are able to abstract general principles and constraints which allow them to interpret and produce an infinite number of sentences which they have never heard before.(2)Constraints and principles cannot be learned: Children‘s access to general constraints and principles whichgovern language could account for the relatively short time it takes for the L1 grammar to emerge, and for the fact that it does so systematically and without any ―wild‖ divergences. This could be so because innate principles lead children to organize the input they receive only in certain ways and not others. In addition to the lack of negative evidence , constraints and principles cannot be learnt in part because children acquire a first language at an age when such abstractions are beyond their comprehension; constraints and principles are thus outside the realm of learning process which are related to general intelligence.(3)Universal patterns of development cannot be explained by language-specific input: In spite of the surfacedifferences in input, there are similar patterns in child acquisition of any language in the world. The extent of this similarity suggests that language universals are not only constructs derived from sophisticated theories and analyses by linguists, but also innate representations in every young child‘s mind.8.Linguists have taken an internal and/or external focus to the study of language acquisition. What is thedifference between the two? P25-26Internal focus emphasizes that children begin with an innate capacity which is biologically endowed, as well as the acquisition of feature specification as a part of lexical knowledge; while external focus emphasizes the information content of utterances, and considers language primarily as a system of communication.9.What are the two main factors for learning process in the study of SLA from a psychological perspective?P26-27(1) Information Processing, which assumes that L2 is a highly complex skill, and that learning L2 is notessentially unlike learning other highly complex skills. Processing itself is believed to cause learning;(2) Connectionism, which does not consider language learning to involve either innate knowledge or abstractionof rules and principles, but rather to result from increasing strength of associations (connections) between stimuli and responses.10.What are the two foci for the study of SLA from the social perspective? P27(1) Microsocial focus: the concerns within the microsocial focus relate to language acquisition and use inimmediate social contexts of production, interpretation, and interaction. (2) Macrosocial focus: the concerns of the macrosocial focus relate language acquisition and use to broader ecological contexts, including cultural, political, and educational settings.Week10Chapter 5 Social contexts of Second Language AcquisitionPART ONE: Definitionmunicative compet ence: A basic tenet of sociolinguistics defined as ―what a speaker needs to know tocommunicate appropriately within a particular language community‖(Saville-Troike 2003)nguage community: A group of people who share knowledge of a common language to at least some extent.3.Foreigner talk: Speech from L1 speakers addressed to L2 learners that differs in systematic ways from languageaddressed to native or very fluent speakers.4.Direct Correction: Explicit statements about incorrect language use.5.Indirect correction: Implicit feedback about inappropriate language use, such as clarification requests when thelistener has actually understood an utterance.6.Interaction Hypothesis: The claim that modifications and collaborative efforts which take place in social interationfacilitate SLA because they contribute to the accessibility of input for mental processing.7.Symbolic mediation: A link between a person‘s current mental state and higher order functions that is providedprimarily by language; considered the usual route to learning (of language, and of learning in general). Part of Vygosky‘s Sociocultural Theory.8.Variable features: Multiple linguistic forms (vocabulary, phonology, morphology, syntax, discourse) that aresystematically or predictably used by different speakers of a language, or by the same speakers at different times, with the same meaning or function.9.Linguistic context: Elements of language form and function associated with the variable element.10.Psychological context: factors associated with the amount of attention which is being given to language formduring production, the level of automaticity versus control in processing, or the intellectual demands of a particular task.11.Microsocial context: features of setting/situation and interaction which relate to communicative events withinwhich language is being produced, interpreted, and negotiated.12.Accommodation theory: A framework for study of SLA that is based on the notion that speakers usuallyunconsciously change their pronunciation and even the grammatical complexity of sentences they use to sound more like whomever they are talking to .13.ZPD: Zone of Proximal Development, an area of potential development where the learner can only achieve thatpotential with assistance. Part of Vygosky‘s Sociocultur al Theory.14.Scaffolding: Verbal guidance which an expert provides to help a learner perform any specific task, or the verbalcollaboration of peers to perform a task which would be too difficult for any one of them in individual performance.15.Intrapersonal interaction: communication that occurs within an individual's own mind, viewed by Vygosky as asociocultural phenomen.16.Interpersonal interaction: Communicative events and situations that occur between people.17.Social institutions:The systems which are established by law, custom, or practice to regulate and organize the lifeof people in public domains: e.g. politics, religion, and education.18.Acculturation: learning the culture of the L2 community and adapting to those values and behavioral patterns.19.Additive bilingualism: The result of SLA in social contexts where members of a dominant group learn thelanguage of a minority without threat to their L1 competence or to their ethnic identity.20.Subtractive bilingualism: The result of SLA in social contexts where members of a minority group learn thedominant language as L2 and are more likely to experience some loss of ethnic identity and attrition of L1 skills—especially if they are children.21.Formal L2 learning: formal/instructed learning generally takes place in schools, which are social institutions thatare established in accord with the needs, beliefs, values, and customs of their cultural settings.rmal L2 learning: informal/naturalistic learning generally takes place in settings where people contact—andneed to interact with—speakers of another language.PART TWO: Short & Long answers1.what is the difference between monolingual and multilingual communicative competence?Differencese between monolingual and multilingual communicative competence are due in part to the different social functions of first and second language learning, and to the differences between learning language and learning culture. The differences of the competence between native speakers and nonative speakers include structural differences in the linguisitc system, different rules for usage in writing or conversation, and even somewhat divergent meanings for the ―same‖ lexical forms. Further, a multilingual speaker‘s total communicative competence differs from that of a monolingual in including knowledge of rules for the appropriate choice of language and for switching between languages, given a particular social context and communicative purpose.2.what are the microsocial factors that affect SLA? P101-102a) L2 variation b) input and interaction c) interaction as the genesis of language3.What is the difference between linguistic & communicative competence (CC)?Linguistic competence- It was defined in 1965 by Chomsky as a speaker's underlying ability to produce grammatically correct expressions. Linguistic competence refers to knowledge of language. Theoretical linguistics primarily studies linguistic competence: knowledge of a language possessed by ―an ideal speak-listener‖.Communicative competence- It is a term in linguistics which refers to ―what a speaker needs to know to communicate appropriately within a particular language community‖, such as a language user's grammatical knowledge of syntax ,morphology , phonology and the like, as well as social knowledge about how and when to use utterances appropriately.4.Why is CC in L1 different from L2?L1 learning for children is an integral part of their sociolization into their native language community. L2 learning may be part of second culture learning and adaptation, but the relationship of SLA to social and cultural learning differs greatly with circumstances.5.What is Accommodation Theory? How does this explain L2 variation?Accommodation theory: Speakers (usually unconsciously) change their pronunciation and even the grammatical complexity of sentences they use to sound more like whomever they are talking to. This accounts in part for why native speakers tend to simply their language when they are talking to a L2 learner who is not fluent, and why L2 learners may acquire somewhat different varieties of the target language when they have different friends.6.Discuss the importance of input & interaction for L2 learning. How could this affect the feedback providedto students?ⅰ. a) From the perspective of linguistic approaches: (1) behaviorist: they consider input to form the necessary stimuli and feedback which learners respond to and imitate; (2) Universal Grammar: they consider exposure to input a necessary trigger for activating internal mechanisms; (3) Monitor Model: consider comprehensible input not only necessary but sufficient in itself to account for SLA;b) From the perspective of psychological approaches: (1) IP framework: consider input which is attended to as essential data for all stages of language processing; (2) connectionist framework: consider the quantity or frequency of input structures to largely determine acquisitional sequencing;c) From the perspective of social approaches: interaction is generally seen as essential in providing learners with the quantity and quality of external linguistic input which is required for internal processing.ⅱ. Other types of interaction which can enhance SLA include feedback from NSs which makes NNs aware that their usage is not acceptable in some way, and which provides a model for ―correctness‖. Whil e children rarely receive such negative evidence in L1, and don‘t require it to achieve full native competence, corrective feedback is common in L2 and may indeed be necessary for most learners to ultimately reach native-like levels of proficiency when that is the desired goal.7.Explain ZPD. How would scaffolding put a student in ZPD?Zone of Proximal Development, this is an area of potential development, where the learner can achieve that potential only with assistance. Mental functions that are beyond an individual's current level must be performed in collaboration with other people before they are achieved independently. One way in which others help the learner in language development within the ZPD is through scaffolding. Scaffolding refers to verbal guidance which an expert provides to help a learner perform any specific task, or the verbal collaboration of peers to perform a task which would be too difficult for any one of them individually. It is not something that happens to learners as a passive recipient, but happens with a learner as an active participant.8.Think of a macrosocial factor that affects English learning in China. Which of does it fall under? What arethe effects? What are the results?The 5 topics are:●Global abd national status of L1 and L2●Boundaries and identities●Institutional forces and constraints●Social categories。

东师范英语课程与教学论16秋在线作业2免费答案

东师范英语课程与教学论16秋在线作业2免费答案：4aad64d5-0010-4420-bc3b-3112d6d8a80f：b415d426-74ef-4728-b507-a3ec0554e3a0英语课程与教学论16秋在线作业21：In the following sentences， which one is wrong?()A：Vary instructions could enrich course contents.B：Vary instructions enhance opportunities for learning rnEnglish.C：Vary instructions helps develop students’language awareness.D：Vary instructions enhance the students’memory ability.正确答案：D2：If a writing task is more general (for example， developing informal letter writing skills)， then what is the best approch of correction?A：teacher-guided correctionB：group correctionC：focus correcting正确答案：B3：()is an intensive study of a specific individual or specific context， which is usually based on the assumptionA：Action researchB：Teaching journalC：Lesson reportD：A case study正确答案：D4：The first of the “natural methods”is (). A：Direct MethodB：Grammar-translation MethodC：the Audio-lingual MethodD：Situational Language Teaching正确答案：A5：A () activity is used where the whole set of information is not revealed until allstudents have performed their part of the task.A：jigsawB：gap-fillingC：hungmanD：bingo正确答案：A6：The biggest problem for group work is the selection of group members. Below are some possible ways to group students. Each of them is appropriate except ().A：group the students according to seating arrangementB：students select their own group members (risky)C：group the students by drawing lotsD：divide the strong students and the weak students into different groups正确答案：D7：David Nunan (1991) offers () points tocharacterize the Communicative Approach: A：fiveB：sixC：sevenD：four正确答案：A8：Which expression about eliciting is incorrect?()A：Eliciting involves the class by focusing students’ attention and making them think. B：Eliciting encourages students to draw on what they already know or partly know. C：Eliciting takes less time than straightforward presentation of new language.D：Eliciting g正确答案：C9：The root of a word is also called the ________.A：stemB：suffixC：base formD：A or C正确答案：D10：Cognitive and interactional patterns cannot affect the way in which students? A：perceiveB：rememberC：thinkD：practice正确答案：D11：Which expression is wrong about learning students' names?()A：Help show students that the teacher is interested in them.B：It shows the teacher is responsible. C：The teacher could ask individual students to assist with demonstrations.D：The teacher could ask individual students to assist with equipment in the class.正确答案：B12：Students work in pairs， each having similar pictures，but with differences. Through talking to each other， they have to find out the differences without looking at each other’s pictures. What is the name of this speaking activityA：Reaching a consensusB：Describe and arrangeC：Find out the differenceD：Work out the story正确答案：C13：In the learning the established understanding is typical by _ syllabus. A：Formal and functionalB：structural and functionalC：formal and structuralD：type A and type B正确答案：A14：One of the principles of the Direct Method is that classroom instruction was conducted exclusively in the ()language. A：nativeB：another newC：targetD：first正确答案：C15：Which is not belongs to cognitive strategies?A：resourcingB：self-managementC：translationD：inferencing正确答案：B16：Which opinion of using English in the classroom is wrong?()A：teacher-guided correctionB：group correctionC：focus correcting正确答案：C17：Among speaking strategies，which involves using alternatives for words which you do not know?A：Tailoring message to competenceB：ParaphrasingC：Using fillers and hesitation devices D：Appealing for help正确答案：B18：()involves teachers identifying issues and problems relevant to their own classes. A：Literature reviewB：QuestionnaireC：Action researchD：lassroom observation正确答案：C19：The most common form of authority involved in developing language policy and planning is the ().A：governmentB：courtC：procuratorateD：Public Security Bureau正确答案：A20：________is a word game in which you write answers to questions in a pattern of numbered boxes.A：anagramB：crosswordC：riddleD：word puzzle正确答案：B21：The motivation of a student who wishes integrate with the L2 culture is what? A：intrinsicB：integrativeC：instrumentalD：extrinisicE：external正确答案：AB22：Sensory Modality Strength categorizes learners as what?A：visualB：auditoryC：tactile-kinestheticD：thinkingE：analytical正确答案：ABC23：What could teachers do in class when there are still a few minutes to go?()A：The teacher could invite one more pair to report their work to the whole class.B：The teacher could review what has gone on in class today.C：The teacher could ask students study by self.D：The teacher could the students what they will be doing in the next c正确答案：ABD24：() and () have both linguistic outcome and non-liuguistic outcome.A：exerciseB：activityC：approachD：task正确答案：BD25：There are three things to prepare your memory to retain words for a longer time，they are________A：understandingB：associatingC：visualizingD：memorizing正确答案：ABC26：In the following， which are controlled writing activities?A：copyingB：gap-fillingC：Making listsD：Sentence completion正确答案：AB27：Effective teachers have command of at least three， broad knowledge bases that deal with ().A：subject matterB：human development and learningC：pedagogyD：healthy habbit正确答案：ABC28：Errors could be divided into three groups，they are().A：interference errorsB：intralingual errorsC：systematic errorsD：developmental errors正确答案：ABD29：What are the functions of teacher talk?()A：teachingB：socializationC：organizationD：managemant正确答案：ABC30：For most cases， teachers have to search for and develop their own strategies to maintain discipline in their classroom. Which measures do you think are proper for indisciplined acts and badly behaving students().A：talk to students in the classB：stop the classC：change the activityD：rearrange the seatsE：putting them in the corridor正确答案：BCD31：Teaching journals， lesson report， Audio and video recordings and survey and questionnaires and action research are majorinstruments in action research.A：错误B：正确正确答案：A32：It is best to correct all the mistakes students make in the class.A：错误B：正确正确答案：A33：After the class observation， it is not necessary for the class instructor and the observer to schedule a post-session.A：错误B：正确正确答案：A34：Ideally， lesson planning should be done at two levels: macro planning and micro planning.A：错误B：正确正确答案：B35：Classroom management is the way teachers organize what goes on in the classroom. A：错误B：正确正确答案：B36：Type A and B syllabus contrast an interveationist and a non-interveationist approach， being respectively concerned with the?“what”?and the?“how”?of learning. A：错误B：正确正确答案：B37：The role of English and other foreign languages differs widely from one country to anotherA：错误B：正确正确答案：B38：According to what the students are expected to do， classroom activities can be divided into two main categories: those that give the student language input， and those that encourage the students to produce output.A：错误B：正确正确答案：B39：Survey is used widely in descriptive research， in which sampling is one of the key issues.A：错误B：正确正确答案：B40：Information gap is a situation in which information is known to only some of the participants in communication of two or morepeople and those who do not have the information are interested in finding it out.A：错误B：正确正确答案：B41：The teacher’s role can be defined as controller，assessor，organizer，prompter，participant and resource-provider.A：错误B：正确正确答案：B42：Five elements of reflective teaching model are linear or sequential and always followed by the next element in the cycle. A：错误B：正确正确答案：A43：A lexical item may be more than a single word.A：错误B：正确正确答案：B44：Before the end of the 1950s， the mastery of language structures was the main measure of competence in a foreign language，A：错误B：正确正确答案：A45：Fluency describes a level of proficiency in communication which includes the ability to produce written and/or spoken language with ease.A：错误B：正确正确答案：B46：Teachers and students need to understandthat learning a foreign language means giving up one’s first language or dialect. A：错误B：正确正确答案：A47：A task means that learners use whatever target language resources they have in order to solve a problem， do a puzzle， play a game，or share and compare experiences.A：错误B：正确正确答案：B48：A task is a goal-oriented activity in which learners use language to achieve a real outcome.A：错误B：正确正确答案：B49：Errors can indicate the student'sstage of language learning and acquistion. A：错误B：正确正确答案：B50：If nobody corrects leanrners' error， they will never learn good English. A：错误B：正确正确答案：B。

A Comprehensive Framework for Broadcasting Multimedia Content

© 2002 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material foradvertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.A Comprehensive Framework for Broadcasting MultimediaContent in the Future Mobile InternetCristian Hesselman 1,2, Ing Widya 2, Henk Eertink 1, and Erik Huizer 21Telematica Instituut, The Netherlands{hesselman, eertink}@telin.nl 2University of Twente, The Netherlands{widya, huizer}@cs.utwente.nlAbstractIn this paper, we present a comprehensive role-based framework for multimedia broadcasts (e.g., for applications such as TV, radio, e-cinema, and e-learning) taking place in a heterogeneous mobile Internet. The added value of the framework is the strong separation between application and network-level roles in combination with support for unrestricted mobility. The framework concentrates on the perceptual quality levels at which broadcasts can be received and does not require any IP-level QoS or mobility functions.We are currently developing an application-level platform that is based on the framework.1. IntroductionThe mobile Internet of the future will consist of many different Internet Service Providers (stationary and moving,public and private) that offer IP-level connectivity to a wide variety of mobile devices (from laptops down to PDAs) [1-3].The network infrastructure of these Internet Service Providers (ISPs) will consist of one or more subnets [4], which may be based on different network technologies (e.g., wireless LAN hot spots in cellular environments) [1]. The coverage areas of such heterogeneous subnets may overlap, thus opening up possibilities for the delivery of seamless services to mobile users.We are currently developing an application-level platform that supports multimedia broadcasts [5-10] (e.g., for applications such as TV, radio, e-cinema, and e-learning [11])taking place in the environment outlined above.In this paper, we introduce the framework that we are using as a context for the design and development of our platform. The framework is based on functional roles (cf. [13,14]). It follows current trends in content distribution in that it separates network-level roles (i.e., ISPs) from application-level roles [11, 15, 16] (e.g., performed by Akamai-like organizations). The principal application-level roles are mobile clients (i.e., mobile devices) and access streamers.Access streamers are mobility and quality aware and send multimedia broadcasts to mobile clients via ISPs. In this paper, we do not require any QoS and mobility functions (e.g., IntServ, Mobile IP, etc.) from ISPs.We focus on the challenge of unrestricted mobility [3, 17-21]. This means that clients must be able to move across subnets, ISPs and access streamers, possibly in an overlay situation [18, 20] and while they receive a broadcast.The added value of our framework is the strong separation between application and network-level roles in combination with support for unrestricted mobility. As a result of our application-network separation, a user has a subscription with at least one home access streamer and one home ISP (cf.[14]). For the same reason, we also distinguish between application-level handoffs [24-29], network-level handoffs [18, 20, 30-35], and application and network-level roaming agreements [21, 36, 37].We furthermore concentrate on the perceptual quality level [11, 22, 23] at which a client receives a broadcast (e.g.,at a ‘TV’ quality level) and the required changes as a result of mobility [23] (e.g., from a ‘TV’ to a ‘videophone’ quality level).The work that comes closest to ours is that of MarconiNet [12]. However, they do not use a strict application-network separation, nor do they consider quality issues. In addition,they do not seem to explicitly address an environment involving different wired and wireless network technologies.In this paper, we zoom in on the framework’s information model and ignore the underlying protocols and mobility mechanisms (e.g., handoff mechanisms).The rest of this paper is organized as follows. We first discuss our model of a multimedia broadcast in Section 2. We then explain the roles of our framework in more detail in Section 3, concentrating on clients and access streamers. We consider the case of a user accessing broadcast services in Section 4, and the user moving around in Section 5. We close with conclusions and future work in Section 6.2. ChannelsA channel [38] carries the content of a multimedia broadcast (e.g., ‘world news’). Channels are available at various perceptual quality levels [11, 22, 23] and can for instance be based on perceived quality assessments [23, 39]. Quality levels can be described in the form of parameters such as frame rate and pixel count [40], or in the form of well-known end-user friendly labels such as ‘videophone’ or ‘TV’ quality [11, 22]. In this paper, we will use the latter to better align with our end-user orientation.Each quality level ultimately maps to a set of encoded and packetized digital streams. These streams may be based on multiple well-defined packet formats (e.g., RTP formats [41]‘video-h261’ and ‘video-mpeg4’ [42]). Clients must receive all the streams of a specific packet format (e.g., those based on ‘video-mpeg4’) to get the associated quality level [7, 10, 43].Box 1 shows a pseudo-XML description (cf. [44]) of achannel carrying the world news of a TV network. Receivers of the channel can for instance tune into quality level ‘videophone’ by subscribing to the appropriate streams (e.g.,the MPEG4/RTP ones).Box 1: Channel description.3.RolesThe primary roles of our framework are (mobile) clients, access streamers, and ISPs.A client receives a channel from an access streamer via (a subnet of) an ISP, depacketizes and decodes the channel’s a/v content, and presents it to the mobile end-user. Examples of clients are laptops, PDAs, and pen tablets.An access streamer delivers channels to mobile clients at mobile-specific quality levels (e.g., ‘mobile TV’1). An access streamer keeps track of the subnets through which it serves its clients at which quality levels. It uses this information as an input for a policy-based procedure that controls the availability of quality levels (see Section 4). For example, an access streamer could use a policy that only makes high-end quality levels available when there are enough clients that have the capabilities to receive the quality level.An ISP conveys channels from access streamers to clients. The network infrastructure of an ISP consists of wired or wireless IP subnets. In this paper, we do not require any QoS and mobility functions (e.g., IntServ, Mobile IP, etc.) from ISPs.An access streamer may be co-located with an ISP [12] (e.g., in the case of a walled-garden telco operator). Alternatively, an access streamer may be separated from the ISPs it serves. In this case, the access streamer (e.g., an Akamai-like organization) connects to the ISPs through backbone connections. Figure 1 illustrates both possibilities for the distribution of channel ‘world news’ via an access streamer AS and an ISP I.1 From now on, we prefix quality labels with ‘m-’ instead of ‘moblile’(e.g., ‘m-TV’).channel ‘world news’(a)(b)Figure 1: Collocated (a) and separated (b).The set of access streamers that a client can reach from one subnet may different from the set of access streamers it can reach from another subnet. For example, the client in Figure 2a can reach access streamers AS1 from subnet N1 and AS2 from subnet N2. This situation might for instance occur when AS1 and N1 belong to one organization (cf. Figure 1a), and AS2 and N2 to another (e.g., two telco operators). Alternatively, N1 and N2 could be part of two different ISPs that each use separate access streamers AS1 and AS2 (e.g., two Akamai-like organizations). Figure 2b shows an example in which a client can reach the same access streamer (AS) from two different subnets, N3 and N4. This situation can for instance occur when N3 and N4 belong to different ISPs that both use AS as a separate access streamer. Figure 2c and 2d show similar configurations for overlays [18, 20]. We will useFigure 2c as a running example throughout this paper.(a)(b)(c)(d)coverage area of subnet NiFigure 2: Reachability.The access streamers that a client can reach are either the original source of a channel or an intermediary. In addition, the distribution of a channel may involve streamers that are not mobility-aware (i.e., that are not access streamers). We use the roles of an origin streamer and a surrogate streamer [15] to model these situations.An origin streamer is the source of a channel. It manages the multimedia content of content creators (e.g., CNN, Walt Disney, and universities), digitizes the content into channels, and forwards them to access or surrogate streamers. An origin streamer that also possesses mobility functions is an access streamer.A surrogate streamer is an intermediary that can manipulate channels [5, 6, 22, 23, 43, 45, 46]. It can for instance reduce the quality of channel ‘world news’ (Figure 1) from a ‘TV’ to a ‘videophone’ level, or transcode to another encoding format. However, the content provider ultimately determines which operations are allowed (e.g., no transcoding for commercial content). A surrogate streamer receiveschannels from origin streamers or surrogate streamers, and forwards them to access streamers or to other surrogate streamers. A surrogate streamer that also possesses mobility functions is an access streamer.Figure 3a shows an access streamer (AS) that is the origin source of channel ‘world news’ (end-to-end approach).Figures 3b and 3c show access streamers that are intermediaries. The access streamer of Figure 3b directly connects to an origin streamer (OS), whereas the access streamer of Figure 3c connects to the origin streamer through one (or more) surrogate streamers (SS). The streamers and the clients thus form a tree. For simplicity, Figure 3 does not show ISPs.channel ‘world news’treeFigure 3: End-to-end (a) and proxied (b, c).4. AccessIn this section, we address the case in which a user logs onto a client to access broadcast services. Since a client may be able to reach multiple access streamers, ISPs, and subnets from its current location (cf. Figure 2), service access may require the client to interact with a mixture of home and foreign access streamers and ISPs. In this section, we assume that clients do not move.In our framework, access to broadcast services involves four logical phases: subscription (Section 4.1), browsing (Section 4.2), establishment (Section 4.3), and usage (Section 4.4). In this paper, we concentrate on the results of these phases. We also summarize their relationship to the roles of our framework (Section 4.5).4.1 SubscriptionThe result of the subscription phase consists of a delivery agreement between the end-user and an access streamer (the user’s home access streamer) and a connectivity agreement between the end-user and an ISP (the user’s home ISP).A delivery agreement defines the quality levels at which the user can potentially receive channels from the access streamer. For each supported quality level, a delivery agreement also defines constraints that limit the availability of the quality level, for example to a certain time of day, or to certain types of clients (e.g., clients with a sufficiently large display).Box 2 shows an example of a delivery agreement between user tom@domain and its home access streamer AS1. The agreement shows that tom@domain can potentially receive three quality levels from AS1: ‘m-TV’, ‘m-videophone’, and ‘m-thumbnail’. The constraints limit the availability of these quality levels to ‘m-TV’ and ‘m-thumbnail’ between 9am and1pm, or to ‘m-videophone’ and ‘m-thumbnail’ between 1pm and 9pm.Box 2: Delivery agreement.The set of supported quality levels and the constraints of a delivery agreement are based on the policies of the access streamer. These policies may pertain to resource usage (e.g.,high-end quality levels such as ‘m-TV’ are not supported during rush hour) and subscription types (e.g., a ‘bronze’subscription only supports low-end quality level ‘m-thumbnail’).A connectivity agreement defines which subnets a user can access (e.g., 802.11 and UMTS subnets) and the maximum amount of IP-level resources (typically bandwidth)the user can consume on these subnets. Box 3 shows an example in which tom@domain can use the 802.11 and UMTS subnets of its home ISP, ISP1. The 802.11 subnet is however only accessible between 9am and 1pm.Box 3: Connectivity agreement.Delivery agreements and connectivity agreements are pre-negotiated [14] (beyond the scope of this paper). They typically exist as long as the end-user has a subscription with the associated access streamer and ISP, respectively.4.2 BrowsingThe browsing phase starts when the user has logged onto a client and starts the application from which it can access channels (typically an electronic program guide like the Mbone tool sdr). The result of the browsing phase consists of a list of high-level channel descriptions (e.g., in the form of their names) that the client presents to the user. The client uses the access streamers (home and foreign) it can reach at its current location to construct the list.4.3 EstablishmentThe establishment phase begins when a user selects a channel (e.g., ‘world news’) and results in a channel state and a connectivity state.A channel state indicates which reachable access streamers support the channel the user has selected. For each of these access streamers, the channel state also specifieswhich quality levels are available to the client to receive the channel. A channel state exists as long as the user has selected the channel.Box 4 illustrates what a channel state might look like for Figure 2c. In this case, user tom@domain uses mobile client C. C can choose between access streamers AS1 and AS2 that both offer ‘world news’ at the client’s current location. Access streamer AS1 offers C two of tom@domain’s quality levels (‘m-videophone’, and ‘m-thumbnail’, cf. Box 2) for channel ‘world news’. Observe that the channel state of Box 4 also indicates how the access streamer or the client expects to receive feedback on the quality levels. RTCP can used for this purpose, but due to the coarse granularity of RTCP feedback we prefer to use an application-level beaconing algorithm [47]with a frequency described in the channel state.Box 4: Channel state.A channel state is the result of an on-the-fly negotiation procedure (e.g., based on SIP [49], RTSP [48] or RTCP [41]) that takes the availability of resources on the client and in the access streamers into account. As a result, some of an access streamer’s supported quality level may not appear in a channel state (e.g., ‘m-TV’ in Box 4).A channel state generally involves of a mixture of home and foreign access streamers. For example, the channel state in Box 4 involves one home access streamer (AS1) and one foreign access streamer (AS2). The quality levels available from a home access streamer are constrained by the delivery agreement with the end-user. For example, quality level ‘m-videophone’ (AS1) will not appear in the channel state of Box 4 if it does not appear in the user’s delivery agreement (see Box 2).For foreign access streamers, the channel state is furthermore based on roaming agreements. A home access streamer establishes a roaming agreement with a foreign access streamer so that its clients can use the foreign access streamer to receive channels. A roaming agreement specifies a mapping between the quality levels of a home access streamer and those of a foreign access streamer. This mapping ultimately influences the list of quality levels the client can receive from the foreign access streamer.Box 5 illustrates what a roaming agreement might look like. In this case, the ‘m-TV’ quality level of the home access streamer AS1 maps to the same level at the foreign access streamer AS2. The ‘m-videophone’ and ‘m-thumbnail’quality levels both map to the thumbnail levels of the foreignaccess streamer.Box 5: Roaming agreement.Observe that the entire roaming agreement of Box 5 can either be established statically (i.e., pre-negotiated) or dynamically. In addition, it can be established bilaterally or through a roaming broker (cf. [36]).A connectivity state indicates which subnets (e.g., 802.11 and UMTS subnets) and ISPs are reachable from the client’s current location. For each reachable subnet, the connectivity state also specifies the amount of IP-level resources that are currently available to receive the selected channel, either through unicast or through multicast. The channel state is derived from the user’s connectivity agreement based on the available resources in the subnets and on the client.Box 6 shows an example of a connectivity state based on the connectivity agreement of Box 3. Observe that the maximum available bandwidth for the UMTS subnet is lower than in the connectivity agreement, for instance because of apolicy of the ISP or because of other traffic.Box 6: Connectivity state.In our framework, roaming agreements are also set up between ISPs (cf. [21, 36, 37]). The purpose of these agreements is similar to streamer-level roaming agreements, but they pertain to network-level roaming issues (e.g., bandwidth).4.4UsageThe usage phase starts with the automatic selection of a quality level and a subnet. This may for instance be done based on user profiles (e.g., containing the user’s preferred quality levels). As an example, suppose that the end-user has selected channel ‘world news’ and that the selected quality level is ‘m-videophone’ of access streamer AS1 (Box 4). In this case, the client must subscribe to multicast groups 224.5.6.7 and 224.5.6.8 to receive the channel at videophone quality in MPEG4 format. The result of the usage phase is that channel is being forwarded to the client at the selected quality level via the selected subnet.The channel and connectivity states may change dynamically during the usage phase. There are various reasons for such a change. For example, the channel state shown in Box 4 may change because AS1 no longer supports ‘m-videophone’ as a result of AS1’s policies. Another reasonmay be that the available bandwidth between the client and access streamer AS1 drops to a level that ‘m-videophone’ can no longer be supported. These events require a re-establishment of the state of Box 3 and might therefore require a renegotiation. The net result may be that another quality level will be selected and that a client must switch to this level (e.g., from ‘m-videophone’ to the ‘m-thumbnail’level) or to another set of streams of the same level (e.g., from m-videophone’s MPEG4 streams to its H261 streams). Observe that the newly selected quality level may belong to another access streamer (e.g., AS2).4.5SummaryFigures 4 and 5 summarize the agreements, states, and roles of our framework in UML [53] class diagrams. For simplicity, we have omitted class attributes and methods, as well as the multiplicities of associations.Figure 4 depicts the relation between users and their home access streamers and home ISPs during the subscription phase (Section 4.1). The delivery agreement of Box 2 illustrates an instance of the association class DeliveryAgreement. User tom@domain and access streamer AS1 are references to instances of classes User and AccessStreamer, respectively. Similarly, the connectivity agreement of Box 3 illustrates an instance of ConnectivityAgreement, while ISP1 is a reference to an instance of class ISP.Figure 4: Class structure during the subscription phase.Figure 5 shows the relations between clients, access streamers, and ISPs during the establishment phase (Section 4.3). The channel state of Box 4 illustrates an instance of class ChannelState. It involves a reference to an instance of Client(C) and two references to instances of AccessStreamer(AS1 and AS2). The roaming agreement of Box 5 illustrates an instance of AS-RoamingAgreement and also involves references to two instances of AccessStreamer (AS1 and AS2).Figure 5: Class structure during the establishment phase.The class diagram of the usage phase (Section 4.4) is similar to that of the establishment phase.5.MovementIn this section, we address the case in which a mobile client moves while it receives a channel (i.e., it is in the usage phase). We concentrate on handoffs at the level of access streamers as a result of handoffs between subnets.Since our framework does not require any IP-level mobility functions, we handle mobility at the application-level [24-29]. We use client-controlled handoffs [50]. In this paper, we assume that clients automatically discover which subnets they can reach (e.g., through DHCP) and update the connectivity state accordingly.The set of available access streamers in the channel state can change when the set of reachable subnets in the connectivity state changes. For example, when the client of Figure 2c moves out of subnet N1, N1 will disappear from the connectivity state while access streamer AS1 and its quality levels will disappear from the channel state. When C moves back into N1, N1 and AS1 will reappear.In our framework, a client can automatically select a new quality level when the channel state changes (e.g., based on the user’s preferred quality levels). The target quality level may be provided by a different access streamer, thus requiring the client to handoff to that access streamer (application-level handoff). To receive the target quality level, the client drops the streams of the old quality level and begins to receive those of the new quality level [47] (adaptation). Experiments with a rudimentary version of our platform [47] showed that it takes several seconds before the streams of the old quality level can be dropped and those of the new quality level can be displayed.To provide continuous service to clients, it may be crucial that the channel state is updated as fast as possible. For example, when client C receives channel ‘world news’ from access streamer AS1 via subnet N1 (Figure 2c) and moves out of N1’s coverage area, it must handoff to access streamer AS2. For a smooth handoff, AS2 must therefore appear in the channel state of ‘world news’ as soon as possible. This requires fast discovery and negotiation procedures. To execute the handoff in a smooth manner, it also requires fast initialization procedures (e.g., when the streams of the target quality level are based on a different packet format).In our framework, the adaptation from one quality level to another is based on policies. In the past, we have developed such adaptation policies in overlay situations using packet loss characteristics [47]. These policies define when a handoffshould start and when it should complete. Similar policies based on available bandwidth are described in [23]. [51] considers network-level policies based on aspects such as available bandwidth, power consumption, and connection set up delay.For reasons of security, we assume that adaptation policies are provided by clients. In a more programmable environment, they can however also be provided by access streamers [52].6.Conclusions and Future WorkWe presented a comprehensive role-based framework for the design of an application-level platform that supports broadcast applications running in a heterogeneous mobile Internet. The framework’s strict separation between application and network-level roles introduces additional complexity due to the duplication of network-level concepts at the application-level (e.g., home locations, roaming agreements, and handoffs). However, standardization efforts (e.g., the OPES and CDI working groups of the IETF) and business cases (e.g., in the form of companies such as Akamai and Digital Island) indicate that this separation is desirable. We are unaware of other work that uses such a model to support unrestricted mobility in a heterogeneous mobile Internet.We have developed a rudimentary version of our platform that allows a mobile client to handoff between two quality levels of two different access streamers in an overlay situation and analyzed its handoff behavior [47]. We are currently implementing a more advanced version of the platform, using the framework outlined in this paper as a starting point.7.References[1]M. Haardt, W. Mohr, “The Complete Solution for Third-Generation Wireless Communications: Two Modes onAir, One Winning Strategy”, IEEE Pers. Comm., Dec.2000[2]H. Yumiba, K. Imai, M. Yabusaki, “IP-Based IMTNetwork Platform”, IEEE Pers. Comm., Oct. 2001 [3]N. Drew, M. Dillinger, “Evolution TowardReconfigurable User Equipment”, IEEE Comm. Mag.,Feb. 2001[4] F. Vakil, A. Dutta, J-C. Chen, M. Tauil, S. Baba, N.Nakajima, Y. Shobatake, H. 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A Frequent Pattern Based Framework for Event Detectionin Sensor Network Stream Data *Li Wan 1,2 1Beijing University of Posts and Telecommunications, Beijing, China 100876 2EBUPT Information Technology Co., Ltd, Beijing, China 100191 wanli@Jianxin Liao 1,2 1Beijing University of Posts and Telecommunications, Beijing, China 100876 2EBUPT Information Technology Co., Ltd, Beijing, China 100191 liaojx@ Xiaomin Zhu 1,21Beijing University of Posts and Telecommunications, Beijing, China100876 2EBUPT Information Technology Co., Ltd, Beijing, China 100191 zhuxm@ABSTRACTIn this paper, we presented a frequent pattern based framework for event detection in stream data, it consists of frequent pattern discovery, frequent pattern selection and modeling three phases: In the first phase, a M NOE (M ining Non-Overlapping Episode) algorithm is proposed to find the non-overlapping frequent pattern in time series. In the frequent pattern selection phase, we proposed an EGMAMC (Episode Generated Memory Aggregation Markov Chain) model to help us selecting episodes which can describe stream data significantly. Then we defined feature flows to represent the instances of discovered frequent patterns and categorized the distribution of frequent pattern instances into three categories according to the spectrum of their feature flows. At last, we proposed a clustering algorithm EDPA (Event Detection by Pattern Aggregation) to aggregate strongly correlated frequent patterns together. We argue that strongly correlated frequent patterns form events and frequent patterns in different categories can be aggregated to form different kinds of events. Experiments on real-world sensor network datasets demonstrate that the proposed M NOE algorithm is more efficient than the existing non-overlapping episode mining algorithm and EDPA performs better when the input frequent patterns are maximal, significant and non-overlapping.Categories and Subject DescriptorsH.2.8 [Information Sy s tem s]: Database M anagement-Data miningGeneral TermsAlgorithmsKeywordsFrequent pattern, temporal data mining, event detection, sensor network1.INTRODUCTIONStream data refers to object sequences annotated with ordered time stamps. In this paper, “stream data”, “temporal data” and“time series” represent the same concept. Frequent patterns aresubsequences of objects that appear in a time series with frequency no less than a user-specified threshold (i.e. minimum support). Each occurrence of a frequent pattern is an instance of this frequent pattern in the given time series.Abundant literature has been dedicated to find frequent patterns in temporal data [1,2,3,4,5,6,7]. Frequent patterns are usually extracted from time series as the features of the time series for different data mining tasks, such as clustering, classification and mining associate rules [8,9,10,11,12,13]. But the methods developed for mining closed frequent patterns often generate a huge number of patterns. People usually need interesting patterns only [14]. In time series, frequent patterns can be categorized into different categories, patterns in different category can represent different features of stream data which might be interesting patterns in different tasks. As shown in Fig.1, different categories of frequent patterns represent different relationships among frequent pattern instances (y, z axis) and their different distributions in time series (x axis). The concepts mentioned in Fig.1 are defined in section 2.There are different kinds of events, such as burst event, regular event and routine event. For example “burst event” are some events may frequently occur in a special short period of time but not or almost not occur in any other period of time. As events consist of frequent patterns, the features of events can be described by the frequent patterns associated with them. Take the time series in Fig.2 as an example, if we set minimum support as 3 and constraint the length of episode no more than 5, let A, B, C, D denote four episodes consist of 5 objects respectively (see Def. 5). It’s obverse that episode A, B, C, D are all frequent, namely appear more than 3 times respectively. But it’s clear that episode A and D don’t occur frequently in all the scope of the time series. If we split the time series into three pieces, we could say that event A and D burst in the second time frame. Episode A and D are both burst episodes and they form a burst event, namely “AD”. We can consider frequent patterns as elements form events in time series.*This work was jointly supported by: (1) National Science Fund for Distinguished Young Scholars (No. 60525110); (2) National 973 Program (No. 2007CB307100, 2007CB307103); (3) Program for New Century Excellent Talents in University (No. NCET-04-0111); (4) Development Fund Project for Electronic and Information Industry (M obile Service and Application System Based on 3G).Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. SensorKDD’09, June 28, 2009, Paris, France.Copyright 2009 ACM 978-1-60558-668-7…$5.00.Different category of frequent patterns form different category of events.Fig.1 Frequent patterns are categorized by the threedimens ions. i.e. the inclus ion relations hip (maximal or non-maximal), the occurrences in time series (episode or sequential pattern) and the pos itions of ins tances in the time s eries (overlapping or non-overlapping).Fig.2 Episode “A” and “D” burst in the second piece of time,and they form a burst event “AD”.In this paper, we focus on discovering non-overlapping episode and selecting frequent pattern in different categories for detecting different kinds of events in temporal data. The contributions of this paper are as follows:z We categorize frequent patterns in time series by the relationship among their instances and the instance distribution. We defined feature flows to represent frequentpatterns and we can get the feature of frequent pattern instance distribution by analyzing the spectral gram of corresponding feature flow.z We presented MNOE algorithm to discover non-overlapping episode and defined significant non-overlapping episode.Based on the presented EGM AM C model, we induced theminimum support for discovering the defined significant non-overlapping episode (see section 3.2.2).z We defined different categories of frequent patterns and events in a time series. We connect them by instance distribution of frequent patterns. We presented EDPA algorithm to aggregate frequent patterns in different category to get different category of event.z Experiments on sensor network datasets demonstrate that M NOE beats the existing algorithm. EDPA can detect events in high accuracy and distinguishing non-overlappingepisode from overlapping episode, significant episode fromnon-significant episode help improving the accuracy of EDPA.The rest of the paper is organized as follows: Section 2 is preliminaries. Section 3 presents the frequent patterns based framework for event detection. The proposed algorithms (i.e.M NOE, EDPA) and EGM AM C model are presented in three subsections respectively. Section 4 gives related works. Section 5 gives the experiment results and we conclude in section 6.2.PRELIMINARIESDefinition 1. (Time Series) A sequence of objects, 1122{,,,,...,,}i iT o t o t o t! ! !, where12{,,...,}iO o o o represents the symbols of different typesof objects andit the time of occurrence of the i th object. Definition 2. (Frequent Pattern) A subsequence of object symbols(i.e.1{,,...,}j iP o o o) that appear in a time series with frequency no less than a user-specified threshold (i.e. minimum support).Definition 3. (Maximal Frequent Pattern) Given a frequent pattern 12{,,...,}i mP o o o, there do not exist another frequentpattern12{,,...,}j nP o o o includesiP. Ifi jP P, then()()i i j jP o P o,i jo o, where ()i iP o represents theindex of symbolio iniP.By defining different measures of the contribution that the occurrences of objects made to supports, we can get different kinds of frequent patterns, namely sequential pattern and episode. Definition 4. (Sequential Pattern) Given a set of time segmentsand a minimal supportSJ. A sequence occurs once or more than once in a segment contributes 1 to its support. If a sequence’ssupport is larger thanSJ, it’s a sequential pattern.Definition 5. (Episode) Given a time series and a minimal support EJ. A sequence occurs once in this time series contributes 1 toits support. If a sequence’s support is larger thanEJ, it’s an episode.Laxman etc. [15] is the first one defines non-overlapping episodeas follows:Definition 6. (Non-overlapping episode) Suppose an episode occurs in the time series twice, if any object associated with either occurrence doesn’t occur between the objects associated with the other occurrence, then these two instances of the episode are called non-overlapping episode. The frequency of an episode is defined as the maximum number of non-overlapping occurrencesof the episode in time series.To describe the distribution of frequent patterns in a time series, we defined feature flows.Definition 7 (Feature Flow) Suppose a time series 1122{,,,,...,,}i iT o t o t o t! ! ! is segmented intoa segmentation12{(),(),...,()}TSeg s tf s tf s tf. A flow offrequent pattern feature can be written as the sequence:12{(),(),...,()}f f f f T y y tf y tf y tf ,()f i y tf is a measureof frequent pattern featurefin time frame i tf , the sequence oftime frame 12{,,...,}T tf tf tf is a mapping of the segmentationSeg .(())()log((())p f pN s tf N y tf N s tf Nu , where (())p N s tfis the number of occurrence of pattern p in segment ()s tf.(())N s tf is the total number of occurrence of all the frequentpatterns in segment ()s tf .N and p Nare the number of occurrence of all the frequent patterns and pattern p in allsegments respectively.Definition 8 (Event) An event in time series is a set of frequent patterns12{,,...,}n P p p p and any two patterns (i p andj p ) must satisfy the following necessary conditions:1.Their feature flows fi y and fjy must be identicallydistributed.2.i p and j p must occur in the same time segments with highprobability.3.FREQUENT PATTERN BASEDFRAMEWORK FOR EVENT DETECTIONThe presented frequent pattern based event detection framework consists of frequent pattern discovery, frequent pattern selection and modeling. In frequent pattern discovery phase, we can use any existing algorithms to discovery various types of frequent patterns (sequential pattern and episode) and section 3.1 presents the proposed MNOE algorithm which can discovery non-overlapping episodes. For different data mining tasks, there are many methods have been proposed to select interesting frequent patterns from the closed set of frequent patterns. In section 3.2, we present a M arkov chain based method to distinguish significant and non-significant episode and it can be used as a method to select frequent pattern. Finally, in modeling phase, different models can be trained from selected frequent patterns to achieve different tasks (e.g. clustering, classification and associate rule). In section 3.3, we present EDPA algorithm which clusters frequent patterns for event detection in stream data.3.1Finding Non-overlapping EpisodesThe concept of non-overlapping episode was firstly proposed by S.Laxman etc. [15] (see Def. 6). But it’s regret that S. Laxman etc. [15,16] only proposed an algorithm to find non-overlapping episodes from the complete set of episodes. It’s obviously not efficient. So based on the same definition of non-overlapping episode and its frequency, we present a iterative algorithm which directly find non-overlapping episodes from the given time series. Algorithm MNOE Input:1.a set S of time annotated time series projection,P head body !2.The length of episode to be found in current iterate: l3.The maximum time interval permitted between every twosuccessive events in an episode: maxGap 4. minimum support: minSpt Output: the set of non-overlapping episodes1.Sortingi P increasingly in S by the time stamp annotedto the last element in .i P head 2.for (every projection i P in S){3. for every element e in .i P body {4.If (substraction of ._e time stamp and the time stamp of the last element in .i P head is largerthan maxGap) then 5. Break; 6.Ifeis the element belonging to |e| withsmallest time stamp in.i P bodyand thetime stamp of the first element in .i P head is larger than the time stamp of last element in HashtableFE(|e|), then 7. e contribute 1 to the support of |e|. 8. Project e on .i P body :i P c =projection(e );9. .()i S add P c c 10. For every key value (i.e.|e|) in HashtableFE 11. if HashtableFE(|e|).size is larger than min Spt 12.Call MNOE(S c ,1l ,m ax G ap ,min Spt )Operator|.|on a sub-sequence x (i.e.||x ) means don’tconsider the annotated time stamps on x . For example, ||e represents an event type, ||,_ee time stamp !represents an instance of ||e appears in time series at_time stamp . So |.|i P head represents the prefix ofepisodes in current iterate, .i P head represents the instances. .i P body represents the set of all events occur after .i P head intime series. The sorting of 12{,,...,}n SP P P in line 1 ofM NOE guarantees us getting the maxmum number of non-overlapping occurrentces of the episode. HashtableFE is a hashtable got |e| as the keys, and HashtableFE(|e|) represent the set of event instances following the current prefix |.|i P head . Finally,projection(e ) follows the rule: if i P c is the new projection, then..i i P head P head e c ,.i P bodyc is a sub-set of eventinstances in .i P body whose time stamps are larger than e .3.2Significant Frequent Episodes3.2.1EGMAMC ModelEGM AM C is a combination of memory M arkov chain andaggregation Markov chain: Suppose12{,,...,,...,}t T X x x x x , where {1,...,}t T ,12{,,...,}t n x E e e e is the state at current time point, Erepresents state space. Then1111(|,...,)()(|)()(|)(|)LLKllt t t L t t l t t l l l k p x x x p l p x x p l p x k p k x ¦¦¦ (1)where L is the maximum time delay permitted (i.e. the maximumtime interval between every successive events permitted in an episode), the state space is categorized into K clusters, ()p l represents the probability that the state at current time point is determined by the state at the l before time points.(|)l t l p k x denotes the probability in which the l before timepoints state determines the current time state belonging to the cluster k .(|)t p x k denotes the probability the state at currenttime point is t x on condition that the current time point state belongs to cluster k .The states in EGMAMC’s state space are categorized into episode event e K and noise n K .e K denotes the events associated withthe episode 121{,,...,,}N N e e e e S S S S D, where ie S represents the event appears in the i th c slot of D and N is the length of D .n K denotes the event not associated with D . Ifset the maximum interval between every two successive events asL , we get the D based EGMAMC model D /:111111(|,...,)(|,...,)(|)(|,...,)(|,)(|)t t t L Llt t L t t l l LKl t t L t t l t l l k P x x x P l x x P x x P l x x P x k x P k x¦¦¦(2)Whent l ex K and,t l nl l x K c c ,1(|,...,)1t t L P l x x c otherwise, 1(1|,...,)1t n t L n Pl x K x K .Set1(,...,)t n t L n P x K x K Owhich indicates theprobability that the time interval of two successive instances ofepisode D is larger than L .O is larger means D distribute more sparsely in the time series, vice versus.Set(|)l n t l P k K x K as the probability that the currentstate belongs to noise (i.e. 1Kis the probability that the current state belongs to episode event). When e kK , if 1n t l e x S , then (|,)1n t e e t l P x S K x ,(|,)0n t e e t l P x S K x z .Whennk K ,1(|,)t n t l P x K x M, where M is thenumber of event type which could appear in the given time series. We suppose the noise obeys an independent identical distribution. Based on the definition above, given an observed time series o ,it’s generated by D /in the probability:()()()()()()()()(1)()(|)(1)()((1))()((1)(1))(1)(1)()()()1(1)(1)()()()1(1)(1)()()n en e n n e e n eq o q o e n n e e T e ee q o q o q o q o q o T q o T q o T P o M MM MM MM MO D O O OKO K O K O K O O K K O K O O K K O K O O KK Kc / (3)Where ||To denotes the length of the observed time series,()n n q o is the times noise states transit to noise states in o .Similarly, ()en q o represents the times noise states transit to the first event in D (i.e.1eS ).()ne q o denotes the times episode states transit to noise state, ()ee q o c represents the times episodestates transit to all the episode states “except” 1e S ,()ee q o represents the times episode states transit to all the episode states.We could approximately consider ()ee q o Nf D, so we getequation (4) from (3) as follows:(1)(1)(1)(|)()()N f T M P o MD O O D O O KK K/ (4)Informally speaking, if K is larger, D appears less frequently ino , if Ois larger, D distributes more sparsely in o . Nextsection introduces the method to test whether D /is proper to be utilized to describe a given time series o .3.2.2Significance Testing of Frequent EpisodesThis study compare EGMAMC model D /with an i.i.d model by Likelihood ratio testing. If the hypothesis of D /is more proper than i.i.d model to be considered as the generative model of theobserved time series o is accepted, D is called significant episode.We test the alternate hypothesis 1H : time series o is generated by an EGM AM C model D /, against the null hypothesis 0H :time series o is generated by an independent identical distribution model...i i d / If inequation (5) holds then 0H is rejected (i.e.D is significant)10(|)()0(|)P o H L o P o H J!! (J is determined by fixing theprobability of Type , error) (5) According to equation (4), when 11M M K or112O , there is too much noise in time series o , so that 1His equal to 0H . So it’s only necessary to test the two hypothesis under condition 1M M Kand 112O .Since 01(|)(T P o H Mis a constant, inequation (5) is equal to 10(|)(|)P o H P o H J J c ! , and according to equation (3), 1(|)P o H J c !is equal to ()ee q o !*, soinequation (5) is equal to()()e e L o q o c !*(Jis determined by fixing theprobability of Type , error) (6) Type,error is the probability of incorrectly accepting 0H under the condition that ()L o c !*.01(();)(()Tf P P L o H Q MDc !* * (7) Where ()|{;()}|e e Q o q o * !* represents the number of T -length time series which let ()L o c !* hold.()Q *has an upper bound as(1)()(1)k TT kT k Q C MM O O !**d¦(8)k T C is the combination number of choosing k position in a T -length time series to place episode states. There are T O positionsare filled by states which are determined by the noise at the time point before, the combination number of these states is TM O .The remaining positions in the T -length time series should be filled by the states are determined by episode states, and each of these position has (1)M choice of the state, because it could not be chosen as the next episode state. So the combination number is (1)(1)T k MO. After all we get111f kP c D d | )(9) where(.))is the cumulative distribution function of a standardnormal random variable and the approximation holds for large Tdue to the central limit theorem. min ()()1T k M c M O d* is a constant, min ()k O d * represents the minimum O appears in the time series in which k d *. So if given the upper bound of Type ,error H (e.g. 0.5H) then11()cH *(10)WhenTis larger, TM*|, and ()ee q o Nf D, thenaccording to inequation (6), when T f M N D !,0H is rejected.Since in a time series o ,()ee T q o T Nf T T D K , inorder to satisfy 1M M K,(1)T f N M D !must hold.Summarizing above, when Tf MN D !and 12O ,Dissignificant episode in time series o .3.3Frequent Pattern Clustering for EventDetection3.3.1Frequent Pattern Spectral AnalysisIntuitively, an event could be represented by a set of correlated frequent patterns. Instances of different types of frequent pattern have different distributions in a time series segmentation. For example, if a subsequence of objects is an episode in a time series segment, its instances must densely distribute in the segment, otherwise the distribution is sparse. If a subsequence of objects is a sequential pattern in a time series segmentation, it must periodically distribute in the original time series. It’s obverse that a subsequence of objects can both be episode and sequential pattern.Feature flows can be used to describe the distribution of frequent patterns (see Def. 7). Given a feature flowf y , we can decomposeit into frequency components by discrete Fourier transform (DFT):2(1)1(),1,2,...,t iTk Tk f t X y t ek TS¦k X denotes the amplitude of the sinusoid with frequency k .The dominant period of the feature flow is represented by the frequency component which has the maximum signal power. We call this maximum frequency component as dominant power spectrum, i.e. 2max ||||fk S X ,1,2,...,2T k ªº «»,2||||k X indicates the signal power at frequency k T . And thecorresponding dominant period is 2arg max ||||f k kP T X .As shown in table 1, according to the values of f S and f P , we categorize frequent patterns into four categories.Table 1 Categories of frequent patterns and correspondingevent types. Pattern CategoriesFeature flow descriptionEvent CategoriesExamples in officesBurstPattern (episode butnot sequential pattern)High f S ,aperiodic or long-term periodic (2f T P ªº!«»)Burst Event: Just happen in a short time frame with large volume.A fire alarm or an annual conference Regular Pattern (episode and sequential pattern)High f S , short-term periodic(2fT P ªºd «»)Regular Event: Daily HappeneventsWork day MeetingsRare Pattern (neither episode nor sequential pattern,namely noise)Low f S ,aperiodic orlong-term periodicRare Event: Just happen in several short time frames, sometimes this kind of event is very important, sometimes it is only noise Somebody fell downRoutine Pattern (not episodebut sequential pattern)Lowf S , short-term periodic (2f T P ªºd «»)Routine Event: Happen periodically but not so oftencomparatively with regular eventsEvery day cleaning work or biweekly meetingsAs defined in Table 1, different kinds of events can be represented by corresponding categories of frequent patterns, each category of frequent pattern can be interpreted as different combinations ofepisode and sequential pattern. We should note that the detection of rare event is a very important and challenging topic [17], but it’s not proper to represent it by frequent patterns. So in this paper, we don’t discriminate rare event and noise and the clustering algorithm for event detection only considered the other three categories of events.According to the definition of sequential pattern and episode (see Def.4 and 5), if a frequent pattern is episode, it can approximately indicate its high f S feature. If a frequent pattern is sequential pattern, it can approximately indicate its short term periodic feature. So we can map categories of frequent patterns to the combinations of episode and sequential pattern. In this way, we needn’t to do DFT on feature flows when we get all the frequent patterns. It promotes the computing efficiency in practice.3.3.2EDPA AlgorithmIf two patterns (i p and j p ) are representative of the same event,they must satisfy the following necessary conditions: 1.Their feature flows fi y and fjy must be identicallydistributed.2.i p and j p must occur in the same time segments with highprobability.To measure the distribution similarity of feature flows, we introduce mutual information (MI). In information Theory, MI is usually used to measure the distance between two distributions (e.g. ()fi D y and ()fj D y ).((),())fi fj MI D y D y can geta value between [0,1], if ((),())1fi fj MI D y D y ,()fi D y and()fj D y are identical. The value of((),())fi fj MI D y D y gets smaller when the distance of()fi D y and ()fj D y becomes larger.Let i TS denotes the set of time segments containing pattern i p ,to measure the probability of pattern i p andj p occur in thesame time segment, we defined time segment occurrence overlap as follows:||(,)min(||,||)i j i j i j TS TS d f f TS TSFor a set of pattern feature i A , we define its mutual informationdistance and time segment occurrence overlap as follows:,()min ((,))ii i j fi fj A MI A MI f f ,()min ((,))ii i j fi fj A d A d f f To detect events occur in time series is to find a set of pattern feature i A that minimizes the following cost function:1()()()ii i i fjfj A C A d A MI A Su ¦ (11)The underlying event e associated with frequent patterns in i A can be represented as:()iifjfj fj A fufu A S y e y S¦¦(12)The proposed EDPA (Event Detection by Pattern Aggregation) is a greedy algorithm. It initializes the pattern feature set{}i i A f , in each iteration it merges two feature sets togetherif the merged result get a smaller value of the cost function, i.e.()()i j i C A A C A * and()()i j j C A A C A *.Intuitively, frequent pattern features in the same category correlated stronger than those in different categories and it could also be verified by the cost function (equation (11)). So each time, we only input the feature flows of the frequent patterns in the same category to find a special kind of event as defined in Table 1, namely we use the feature flows of burst pattern to detect burst event, the regular pattern to detect regular event etc. Algorithm EDPA Input: feature flows 12{,,...,}n Ff f f represent patterns in12{,,...,}n P p p p Output: events 12{,,...,}m E e e e 1.for everyi f in F2. init 1i fiA S3. sort12{,,...,...,}i n A A A A A in ascendant order 4. while A is not empty 5. .i A A next6.//aggregate patterns set together until the aggregation increase ()i C A7. for every j A in A where i j z8. if ()()ij i C A A C A * and ()()i j j C A A C A *9.i i j A A A * and jA A A 10. min ()i C C A 11. else 12. outputi A as k e into E //represent k e as equation (12)13.iA A A 14. break for loop 15. end if 16. end for 17.end while18.outputE4.RELATED WORKS. Laxman etc. [15] defined non-overlapping episode and proposed the first algorithm to discovery non-overlapping episodes. But unfortunately, the algorithm proposed by S. Laxman etc. can only discover non-overlapping episode from the set of all episodes (including overlapping and non-overlapping ones) , which means this algorithm must based on the result output by a episode discovering algorithm such as WinMiner [3]. M NOE proposed in this paper doesn’t traverse all the episode space, we only pick out our interested ones, namely non-overlapping episodes.Meger and C. Rigotti. [3] proposes a complete algorithm (i.e. WinM iner) to find frequent episode pattern in a single long sequence. WinM iner only constrains the maximum time interval between every two successive events in episodes, so the length of sequential pattern is unbound. But WinM iner does not consider the time interval and position of the objects in the pattern instances. J. Pei and J. Han [2] presented the first algorithm discovering sequential patterns.Giannella et al. [5] proposed a frequent itemsets mining algorithm over data stream which utilizes tilted windows to calculate the frequent patterns for the most recent transactions and maintains a tree data structure (i.e. FP-stream) to represent the frequent itemsets.M anku and M otwani [7] proposed an approximate frequency counts in data streams. Cormode and Muthukrishnan [4] proposed an algorithm to find the hottest k items by group testing. The algorithm is used with the turnstile data stream model which allows addition as well as deletion of data items.Gaber et al. [6] proposed an AOG-based algorithm: Lightweight frequency counting LWF. It can find an approximate solution to the most frequent items on-line using adaptation and releasing the least frequent items regularly in order to count the more frequent ones.There is a series of research projects worked on event detection and correlation of events especially in the database community. TelegraphCQ [21] focuses on meeting the challenges that in handling large streams of continuous queries over high-volume, highly-variable data streams. Aurora [22, 23] manages continuous data stream for monitoring applications; it focuses on DBMS-like support for applications. Borealis [24] provide advanced capabilities that are commonly required by newly-emerging stream processing applications. The STREAM project [25] views stream processing as the running of continuous queries expressed in a query language (CQL) that includes sliding windows and sampling over the data stream. Unfortunately, the mentioned projects do not consider the frequent patterns as an important structure in data streams. In this paper, authors argue that frequent patterns form events in data stream and different types of frequent patterns have different features which also represent different features of events. EDPA presented in this paper cluster frequent patterns into events based on the feature follow of frequent patterns.5.EXPERIMENTAL EVALUATIONWe evaluated the presented framework on two public datasets (MERL and IL dataset) and a dataset come from a smart building project (Smart-Building dataset). All the datasets are generated by。