大学毕业论文---软件专业外文文献中英文翻译

毕业设计（论文）外文文献翻译文献、资料中文题目：软件开发概念和设计方法文献、资料英文题目：文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：班级：姓名：学号：指导教师：翻译日期： 2017.02.14外文资料原文Software Development Concepts and DesignMethodologiesDuring the 1960s, ma inframes and higher level programming languages were applied to man y problems including human resource s yste ms,reservation s yste ms, and manufacturing s yste ms. Computers and software were seen as the cure all for man y bu siness issues were some times applied blindly. S yste ms sometimes failed to solve the problem for which the y were designed for man y reasons including:•Inability to sufficiently understand complex problems•Not sufficiently taking into account end-u ser needs, the organizational environ ment, and performance tradeoffs•Inability to accurately estimate development time and operational costs •Lack of framework for consistent and regular customer communications At this time, the concept of structured programming, top-down design, stepwise refinement，and modularity e merged. Structured programming is still the most dominant approach to software engineering and is still evo lving. These failures led to the concept of "software engineering" based upon the idea that an engineering-like discipl ine could be applied to software design and develop ment.Software design is a process where the software designer applies techniques and principles to produce a conceptual model that de scribes and defines a solution to a problem. In the beginning, this des ign process has not been well structured and the model does not alwa ys accurately represent the problem of software development. However,design methodologies have been evolving to accommo date changes in technolog y coupled with our increased understanding of development processes.Whereas early desig n methods addressed specific aspects of thedevelop ment process, current methods atte mpt to address the entire scope of software development. Software design methods are often classified in reference to the peri od in which the y were introduced and the problems at that time. Driven b y coding and testing problems, tools and methods were developed. Early methods focused on modularity a nd top-down development, and information hiding through abstraction. This led to t he development of structured languages, structured analysis, and data flow analysis.In the last decade or so, the expense involved in automation has shifted from hardware to people. Therefore, the software engineering community has been focused on object oriented (O-O) design and the concept of re-usable code in order to reduce the human cost component. Inefficient designs and develop ment methodologies have been addressed with Computer Aided Software Engineering (CASE) tools, and fourth generation design l anguages. This has been done in an attempt replace the traditional waterf all life c ycle process model under which most existing software has been developed.一、Software Design FundamentalsSoftware design meth ods all aim to provide the software designer wi th a s yste m blueprint. This blueprint usually has three aspects: data, architectural, and procedural.•Data design refers to the data's organization, relationships, access and processing methods.•Architectural design defines the components of the sys tem a nd their relationships.•Procedural design builds on the data and architectural design phases to describe the processing details of the s yste m.Even though there are numerous design methodologies, their basic concepts are ver y similar-All software design methods partition the problem and software into smaller pieces in order to reduce complexity. They all strive to identif y data structures and functions, and provide measur ements for software quality. Some of the common principles in software design include: stepwise refinement, s oftware architecture, program structure, data structure,software procedures, mo d u la r i t y,a b s tr a c t io n,a n d in f o r ma t io n h i d i n g.二、M o d e r n D e s i g n M e t h o d o l o g i e sC o n ve n t io n a l s o f t wa r e d e ve l o p me n t p r a c t ic e s c a n g e n e r a l l y b ema p p e d o n to t h e tr a d i t io n a l l i f e-c y c l e p h a s e s o f a n a l ys i s,f u n c t i o n a ls p e c i f i c a t i o n,d e s i g n,i mp l e me n t a t i o n,t e s t i n g,a n d m a i n t e n a n c e.T h i st h o u g h t p r o c e s s i s i n a d e q u a t e f o r t o d a y's c o m p l e x i n f o r m a t i o n s y s t e m s.As the demand for software is growing much faster than the number of developers, adhering to conventional techniques such as the waterfall method requires too much time, too many people, and is difficult to ma nage. Hence, many new software development technologies have arisen. N e wl y d e ve lo p e d p r a c tic e s a n d mo d e ls d o n o t a tte mp t to s e p a r a te p h a s e s o f s o f twa r e development, such as specification and implementation, but instead focus on the concept of program transformation through stepwise refinement and iteration.1、O b j e c t-O r i e n t e d Te c h n o l o g yObject-Oriented (O-O) software design technology is fundamentally different from the traditional methods described above. With traditional methods, each module is recognized a major step in the overall process and the process goes from one step to the next. On the other hand, O-O design is structured around a model of objects and the functions they perform.O-O programming can be traced to the simulation language SIMULA, a hig h level language developed in the late 60's that introduced object classes as a method to encapsulate data. Later, in the 1970s, Smalltalk was introduced as a complete grapgh design and coding as detail is added to the design. This provides a common language throughout each stage in development. O-O is best applied with specifically designed O-O development tools, but it is important to remember that as a methodology is it not specific to any programming language. Many different programming languages can be used to implement 0-0 technology and design methodologies.Instead of procedures and functions passing data back and forth, in object oriented design, the system is viewed as a collection of objects with messages passed from object to object. Each object has its own set of associated operations.Object-oriented design is based on the idea of information hiding and modularization of both data and processing. It is best used when neither data structure nor processing operations are well defined ahead of time. This is quite useful in today's business environment where requirements are always changing and not very well defined. Thus, it has become quite popular! The concept of objects performing services is a natural way of thinking for both developers and customers. This facilitates understanding the problem domain and a more natural design. In addition, there are many benefits of object-oriented development. These include:•I n h e r i t a n c e c a p i t a l i z e s o n t h e c o m m o n a l t y o f a t t r i b u t e s a n d s e r v i c e s a l l o w i n g c o d e a n d objects to be re-used..I n f o r m a t i o n h i d i n g m a k e s s y s t e m s m o r e s t a b l e b y l o c a l i z i n g c h a n g e s t o o b j e c t s a n d t h e r e b y m a k i n g t h e m r e u s a b l e..T h e o b j e c t-o r i e n t e d d e v e l o p m e n t p r o c e s s i s c o n s i s t e n t f r o m a n a l y s i s,t h r o u g h d e s i g n, t o c o d i n g.More information on Object Oriented Programming principles can be found in Chapter 4-Organization of Programming Languages and Programming Concepts.2、P r o t o t y p i n gPrototyping was invented because end users participating in the development phase found it difficult to understand requirement specifications and conceptual models. However, when it first began being used in the 1980s, most conventional life c ycle developers considered it expensive and time consuming.S i n c e t h a t t i m e,u s e r s a n d d e v e l o p e r s h a v e u s e d p r o t o t y p e s s u c c e s s f u l l y a s a communications tool to demonstrate system requirements. After several prototype iterations, developers have a better understanding of user requirements and users have a better idea of how the system will eventually work, look, and l.T h e n u mb e r o f t i me s th e p r o to t yp e is in c r e me n t a l l y r e f in e d d e p e n d s o n h o w we l l th e u s e r r e q u i r e me n ts a n d u n d e r s t o o d.I t a ls o d e p e n d s o n th e u s e r s n e e d to a d d r e q u ir e me n ts o r c h a n g e p r e v i o u s l y s t a t e d r e q u i r e m e n t s.A f t e re s t a b l i s h i n g a n o v e r a l l a r c h i t e c t u r e a n df r a me w o r k, t h e s ys t e m i s d e v e l o p e d a n d d e l i v e r e d in in c r e me n ts.U s e r s ma y e x p e r i me n t w i t h a n d u s e d e l i v e r e d i n c r e me n t s w h i l e o t h e r s a r e b e i ng d e v e l o p e d.Fo r i n s t a n c e,th e fi r s t p r o t o t yp e ma y b e d e l i v e r e d t h a t i m p l e m e n t s a c e r t a i n s c r e e n w i t h o n l y s o m e a c t i v e m e n u i t e m s.W h i l e u s e r s a r e e x p e r i me n t i n g w i t h t h i s s c r e e n a n d me n u i t e ms,o t h e r s c r e e n s a n d me n u i t e ms a r e c o n c u r r e n t l y b e in gd e v e l o p e d wh i c h la t e r w il l b e c o mb in e d w i th th e e x is t in g p r o to t yp e a s ite vo l v e s.O n c e t h e u s e r i s s a t i s f i e d t h a t t h e p r o t o t y p e m e e t s r e q u i r e m e n t s,t h e p r o t o t y p e i s t r a n s f o r me d i n to th e"s ys t e m".T h i s e ff o r t d e p e n d s o n s e v e r a l f a c to r s. I t ma y i n c lu d e a d d i n g f u n c t i o n a l i t y t h a t w a s n't i n i t i a l l y r e c o g n i z e d a s r e q u i r e d,r e p l a c i n g i n e f f i c i e n t p a r t s o f t h e p r o t o t yp e t o me e t p e r f o r ma n c e c r i t e r i a,o r a d a p t i n g t h e p r o t o t yp e t o f i t t h e u s e r's h a r d w a r e e n vi r o n me n t.P r o t o t y p i n g c a n b e g i n v e r y e a r l y, a f t e r s o m e p r e l i m i n a r y r e q u i r e m e n t s a n a l y s i s h a s d e t e r m i n e d t h e b a s i c f u n c t i o n a l i t y,s c o p e,a n d e n v i r o n m e n t o f t h e p r o p o s e d s o f t w a r e.C o n t r a r y t o t h e t r a d i t i o n a l w a t e r f a l l me t h o d,i n t h e p r o t o t yp i n g,f u n c t i o n a l s p e c i f i c a t i o n s a r e n o t f i x e d.R a t h e r,u s e r s a r e e n c o u r a g e d t o m o d i f y t h e i r r e q u i r e m e n t s a s t h e y t h e m s e l v e s b e g i n t o u n d e r s t a n d t h e m b e t t e r.T h i s i s b e c a u s e u s e r s o f t e n d o n't r e a l l y k n o w w h a t t h e y w a n t u n t i l t h e y s e e i t o n t h e s c r e e n.T h e p r o t o t yp i n g p r o c e s s o f d e mo n s t r a t i o n,r e v i e w,a n d r e f i n e me n t g e t s t h e u s e r m o r e i n v o l v e d i n t h e d e v e l o p m e n t p r o c e s s,g i v i n g t h e m a s e n s e o f o w n e r s h i p d u r i n g t h e p r o c e s s a n d a t f i n a l s y s t e m d e l i v e r y.H o w e v e r,d u e t o t h e m i n d s e t o f"p r o t o t y p e", u s e r s o f t e n f in d i t d iff ic u l t to ve r if y t h a t th e p r o to t yp e s a tis f ie s th e ir r e q u ir e me n ts. T h e r e f o r e, g u id e l in e s mu s t b e e s t a b l i s h e d t o d e te r m in e wh e n t o s to p i te r a t in g a n d th e p r o to t yp e to f in a l p r o d u c t.。

外文文献资料1、Software EngineeringSoftware is the sequences of instructions in one or more programming languages that comprise a computer application to automate some business function. Engineering is the use of tools and techniques in problem solving. Putting the two words together, software engineering is the systemtic application of tools and techniques in the development of computer-based applications.The software engineering process describes the steps it takes to deelop the system. We begin a development project with the notion that there is a problem to be solved via automation. The process is how you get from problem recognition to a working solution. A quality process is desirable because it is more likely to lead to a quality product. The process followed by a project team during the development life cycle of an application should be orderly, goal-oriented, enjoyable, and a learning experience.Object-oriented methodology is an approach to system lifecycle development that takes a top-down view of data objects, their allowable actions, and the underlying communication requirement to define a system architecture. The data and action components are encapsulated, that is , they are combined together, to form abstract data types Encapsulation means that if I know what data I want ,I also know the allowable processes against that data. Data are designed as lattice hierarchies of relationships to ensure that top-down, hierarchic inheritance and side ways relationships are accommodated. Encapsulated objects are constrained only to communicate via messages. At a minimum, messages indicate the receiver and action requested. Messages may be more elaborate, including the sender and data to be acted upon.That we try to apply engineering discipline to software development does not mean that we have all the answers about how to build applications. On the contrary, we still build systems that are not useful and thus are not used. Part of the reason for continuing problems in application development, is that we are constantly trying to hita moving target. Both the technology and the type of applications needed by businesses are constantly changing and becoming more complex. Our ability to develop and disseminate knowledge about how to successfully build systems for new technologies and new application types seriously lags behind technological and business changes.Another reason for continuing problems in application development is that we aren’t always free to do what we like and it is hard to change habits and cultures from the old way of doing things, as well as get users to agree with a new sequence of events or an unfamiliar format for documentation.You might ask then, if many organizations don’t use good software engineering practices, why should I bother learning them? There are two good answers to this question. First, if you never know the right thing to do, you have no chance of ever using it. Second, organizations will frequently accept evolutionary, small steps of change instead of revolutionary, massive change. You can learn individual techniques that can be applied without complete devotion to one way of developing systems. In this way, software engineering can speed changee in their organizations by demonstrating how the tools and techniques enhance th quality of both the product and the process of building a system.2、Data Base System1、IntroductionThe development of corporate databases will be one of the most important data-processing activities for the rest of the 1970s. Date will be increasingly regarded as a vital corporate resource, which must be organized so as to maximize their value. In addition to the databases within an organization, a vast new demand is growing for database services, which will collect, organize, and sell data.The files of data which computers can use are growing at a staggering rate. The growth rate in the size of computer storage is greater than the growth in the size or power of any other component in the exploding data processing industry. The more data the computers have access to, the greater is their potential power. In all walks of life and in all areas of industry, data banks will change the areas of what it is possiblefor man to do. In the end of this century, historians will look back to the coming of computer data banks and their associated facilities as a step which changed the nature of the evolution of society, perhaps eventually having a greater effect on the human condition than even the invention of the printing press.Some most impressive corporate growth stories of the generation are largely attributable to the explosive growth in the need of information.The vast majority of this information is not yet computerized. However, the cost of data storage hardware is dropping more rapidly than other costs in data processing. It will become cheaper to store data on computer files than to store them on paper. Not only printed information will be stored. The computer industry is improving its capability to store line drawing, data in facsimile form, photo-graphs, human speech, etc. In fact, any form of information other than the most intimate communications between humans can be transmitted and stored digitally.There are two main technology developments likely to become available in the near future. First, there are electromagnetic devices that will hold much more data than disks but have much longer access time. Second, there are solid-state technologies that will give microsecond access time but capacities are smaller than disks.Disks themselves may be increased in capacity somewhat. For the longer term future there are a number of new technologies which are currently working in research labs which may replace disks and may provide very large microsecond-access-time devices. A steady stream of new storage devices is thus likely to reach the marketplace over the next 5 years, rapidly lowering the cost of storing data.Given the available technologies, it is likely that on-line data bases will use two or three levels of storage. One solid-state with microsecond access time, one electromagnetic with access time of a fraction of a second. If two ,three ,or four levels of storage are used, physical storage organization will become more complex ,probably with paging mechanisms to move data between the levels; solid-state storage offers the possibility of parallel search operation and associativememory.Both the quantity of data stored and the complexity of their organization are going up by leaps and bounds. The first trillion bit on-line stores are now in use . in a few year’s time ,stores of this size may be common.A particularly important consideration in data base design is to store the data so that the can be used for a wide variety of applications and so that the way they can be changed quickly and easily. On computer installation prior to the data base era it has been remarkably difficult to change the way data are used. Different programmers view the data in different ways and constantly want to modify them as new needs arise modification , however ,can set off a chain reaction of changes to existing programs and hence can be exceedingly expensive to accomplish .Consequently , data processing has tended to become frozen into its old data structures .To achieve flexibility of data usage that is essential in most commercial situations . Two aspects of data base design are important. First, it should be possible to interrogate and search the data base without the lengthy operation of writing programs in conventional programming languages. Second ,the data should be independent of the programs which use them so that they can be added to or restructured without the programs being changed .The work of designing a data base is becoming increasing difficult , especially if it is to perform in an optimal fashion . There are many different ways in which data can be structured ,and they have different types of data need to be organized in different ways. Different data have different characteristics , which ought to effect the data organization ,and different users have fundamentally different requirements. So we need a kind of data base management system(DBMS)to manage data.Data base design using the entity-relationship model begins with a list of the entity types involved and the relationships among them. The philosophy of assuming that the designer knows what the entity types are at the outset is significantly different from the philosophy behind the normalization-based approach.The entity-relationship(E-R)approach uses entity-relationship diagrams. The E-Rapproach requires several steps to produre a structure that is acceptable by the particular DBMS. These steps are:(1) Data analysis(2) Producing and optimizing the entity model.(3) Logical schema development(4) Physical data base design process.Developing a data base structure from user requirements is called data bases design. Most practitioners agree that there are two separate phases to the data base design process. The design of a logical database structure that is processable by the data base management system(DBMS)d escribes the user’s view of data, and is the selection of a physical structure such as the indexed sequential or direct access method of the intended DBMS.Current data base design technology shows many residual effects of its outgrowth from single-record file design methods. File design is primarily application program dependent since the data has been defined and structured in terms of individual applications to use them. The advent of DBMS revised the emphasis in data and program design approaches.There are many interlocking questions in the design of data-base systems and many types of technique that one can use is answer to the question so many; in fact, that one often sees valuable approaches being overlooked in the design and vital questions not being asked.There will soon be new storage devices, new software techniques, and new types of data bases. The details will change, but most of the principles will remain. Therefore, the reader should concentrate on the principles.2、Data base systemThe conception used for describing files and data bases has varied substantially in the same organization.A data base may be defined as a collection of interrelated data stored together with as little redundancy as possible to serve on or more applications in an optimal fashion; the data are stored so that they are independent of programs which use thedata; a common and controlled approach is used in adding new data and in modifying and retrieving existing data within the data base. One system is said to contain a collection of data bases if they are entirely separate in structure.A data base may be designed for batch processing, real-time processing, or in-line processing. A data base system involve application program, DBMS, and data base.One of the most important characteristics of most data bases is that they will constantly need to change and grow. Easy restructuring of the data base must be possible as new data types and new applications are added. The restructuring should be possible without having to rewrite the application program and in general should cause as little upheaval as possible. The ease with which a data base can be changed will have a major effect on the rate at which data-processing application can be developed in a corporation.The term data independence is often quoted as being one of the main attributes of a data base. It implies that the data and the application programs which use them are independent so that either may be changed without changing the other. When a single set of data items serves a variety of applications, different application programs perceive different relationships between the data items. To a large extent, data-base organization is concerned with the representation of relationship between data items and records as well as how and where the data are stored. A data base used for many applications can have multiple interconnections between the data item about which we may wish to record. It can describes the real world. The data item represents an attribute, and the attribute must be associated with the relevant entity. We design values to the attributes, one attribute has a special significance in that it identifies the entity.An attribute or set of attribute which the computer uses to identify a record or tuple is referred to as a key. The primary key is defined as that key used to uniquely identify one record or tuple. The primary key is of great importance because it is used by the computer in locating the record or tuple by means of an index or addressing algorithm.If the function of a data base were merely to store data, its organization would be simple. Most of the complexities arise from the fact that is must also show the relationships between the various items of data that are stored. It is different to describe the data in logical or physical.The logical data base description is referred to as a schema .A schema is a chart of the types of data that one used. It gives the names of the entities and attributes, and specifics the relations between them. It is a framework into which the values of the data-items can be fitted.We must distinguish between a record type and a instance of the record. When we talk about a “personnel record”,this is really a record type.There are no data values associated with it.The term schema is used to mean an overall chart of all of the dataitem types and record types stored in a data he uses. Many different subschema can be derived from one schema.The schema and the subschema are both used by the data-base management system, the primary function of which is to serve the application programs by executing their data operations.A DBMS will usually be handing multiple data calls concurrently. It must organize its system buffers so that different data operations can be in process together. It provides a data definition language to specify the conceptual schema and most likely, some of the details regarding the implementation of the conceptual schema by the physical schema. The data definition language is a high-level language, enabling one to describe the conceptual schema in terms of a “data model” .The choice of a data model is a difficult one, since it must be rich enough in structure to describe significant aspects of the real world, yet it must be possible to determine fairly automatically an efficient implementation of the conceptual schema by a physical schema. It should be emphasized that while a DBMS might be used to build small data bases, many data bases involve millions of bytes, and an inefficient implementation can be disastrous.We will discuss the data model in the following.3、Three Data ModelsLogical schemas are defined as data models with the underlying structure of particular database management systems superimposed on them. At the present time, there are three main underlying structures for database management systems. These are :RelationalHierarchicalNetworkThe hierarchical and network structures have been used for DBMS since the 1960s. The relational structure was introduced in the early 1970s.In the relational model, the entities and their relationships are represented by two-dimensional tables. Every table represents an entity and is made up of rows and columns. Relationships between entities are represented by common columns containing identical values from a domain or range of possible values.The last user is presented with a simple data model. His and her request are formulated in terms of the information content and do not reflect any complexities due to system-oriented aspects. A relational data model is what the user sees, but it is not necessarily what will be implemented physically.The relational data model removes the details of storage structure and access strategy from the user interface. The model provides a relatively higher degree of data. To be able to make use of this property of the relational data model however, the design of the relations must be complete and accurate.Although some DBMS based on the relational data model are commercially available today, it is difficult to provide a complete set of operational capabilities with required efficiency on a large scale. It appears today that technological improvements in providing faster and more reliable hardware may answer the question positively.The hierarchical data model is based on a tree-like structure made up of nodes and branches. A node is a collection of data attributes describing the entity at that point.The highest node of the hierarchical tree structure is called a root. The nodes at succeeding lower levels are called children .A hierarchical data model always starts with a root node. Every node consists of one or more attributes describing the entity at that node. Dependent nodes can follow the succeeding levels. The node in the preceding level becomes the parent node of the new dependent nodes. A parent node can have one child node as a dependent or many children nodes. The major advantage of the hierarchical data model is the existence of proven database management systems that use the hierarchical data model as the basic structure. There is a reduction of data dependency but any child node is accessible only through its parent node, the many-to –many relationship can be implemented only in a clumsy way. This often results in a redundancy in stored data.The network data model interconnects the entities of an enterprise into a network. In the network data model a data base consists of a number of areas. An area contains records. In turn, a record may consist of fields. A set which is a grouping of records, may reside in an area or span a number of areas. A set type is based on the owner record type and the member record type. The many-to many relation-ship, which occurs quite frequently in real life can be implemented easily. The network data model is very complex, the application programmer must be familiar with the logical structure of the data base.4、Logical Design and Physical DesignLogical design of databases is mainly concerned with superimposing the constructs of the data base management system on the logical data model. There are three mainly models: hierarchical, relational, network we have mentioned above.The physical model is a framework of the database to be stored on physical devices. The model must be constructed with every regard given to the performance of the resulting database. One should carry out an analysis of the physical model with average frequencies of occurrences of the grou pings of the data elements, with expected space estimates, and with respect to time estimates for retrieving and maintaining the data.The database designer may find it necessary to have multiple entry points into a database, or to access a particular segment type with more than one key. To provide this type of access; it may be necessary to invert the segment on the keys. Thephysical designer must have expertise in knowledge of the DBMS functions and understanding of the characteristics of direct access devices and knowledge of the applications.Many data bases have links between one record and another, called pointers. A pointer is a field in one record which indicates where a second record is located on the storage devices.Records that exist on storage devices is a given physical sequence. This sequencing may be employed for some purpose. The most common pupose is that records are needed in a given sequence by certain data-processing operations and so they are stored in that sequences.Different applications may need records in different sequences.The most common method of ordering records is to have them in sequence by a key —that key which is most commonly used for addressing them. An index is required to find any record without a lengthy search of the file.If the data records are laid out sequentially by key, the index for that key can be much smaller than they are nonsequential.Hashing has been used for addressing random-access storages since they first came into existence in the mid-1950s. But nobody had the temerity to use the word hashing until 1968.Many systems analysis has avoided the use of hashing in the suspicion that it is complicated. In fact, it is simple to use and has two important advantages over indexing. First, it finds most records with only one seek and second, insertion and deletions can be handled without added complexity. Indexing, however, can be used with a file which is sequential by prime key and this is an overriding advantage, for some batch-pro-cessing applications.Many data-base systems use chains to interconnect records also. A chain refers to a group of records scatters within the files and interconnected by a sequence of pointers. The software that is used to retrive the chained records will make them appear to the application programmer as a contiguous logical file.The primary disadvantage of chained records is that many read operations areneeded in order to follow lengthy chains. Sometimes this does not matter because the records have to be read anyway. In most search operations, however, the chains have to be followed through records which would not otherwise to read. In some file organizations the chains can be contained within blocked physical records so that excessive reads do not occur.Rings have been used in many file organizations. They are used to eliminate redundancy. When a ring or a chain is entered at a point some distance from its head, it may be desirable to obtain the information at the head quickly without stepping through all the intervening links.5、Data Description LanguagesIt is necessary for both the programmers and the data administrator to be able to describe their data precisely; they do so by means of data description languages. A data description language is the means of declaring to data-base management system what data structures will be used.A data description languages giving a logical data description should perform the folloeing functions:It should give a unique name to each data-item type, file type, data base and other data subdivision.It should identify the types of data subdivision such as data item segment , record and base file.It may define the type of encoding the program uses in the data items (binary , character ,bit string , etc.)It may define the length of the data items and the range of the values that a data item can assume .It may specify the sequence of records in a file or the sequence of groups of record in the data base .It may specify means of checking for errors in the data .It may specify privacy locks for preventing unauthorized reading or modification of the data .These may operate at the data-item ,segment ,record, file or data-base level and if necessary may be extended to the contents(value) of individual data items .The authorization may , on the other hand, be separate defined .It is more subject to change than the data structures, and changes in authorization proceduresshould not force changes in application programs.A logical data description should not specify addressing ,indexing ,or searching techniques or specify the placement of data on the storage units ,because these topics are in the domain of physical ,not logical organization .It may give an indication of how the data will be used or of searching requirement .So that the physical technique can be selected optimally but such indications should not be logically limiting.Most DBMS have their own languages for defining the schemas that are used . In most cases these data description languages are different to other programmer language, because other programmer do not have the capability to define to variety of relationship that may exit in the schemas.附录 B 外文译文1、软件工程软件是指令的序列，该指令序列由一种或者多种程序语言编写，它能使计算机应用于某些事物的运用自动化。

软件工程毕业论文文献翻译中英文对照学生毕业设计(论文)外文译文学生姓名: 学号专业名称:软件工程译文标题(中英文):Qt Creator白皮书(Qt Creator Whitepaper)译文出处:Qt network 指导教师审阅签名: 外文译文正文:Qt Creator白皮书Qt Creator是一个完整的集成开发环境(IDE)，用于创建Qt应用程序框架的应用。

Qt是专为应用程序和用户界面，一次开发和部署跨多个桌面和移动操作系统。

本文提供了一个推出的Qt Creator和提供Qt开发人员在应用开发生命周期的特点。

Qt Creator的简介Qt Creator的主要优点之一是它允许一个开发团队共享一个项目不同的开发平台(微软Windows?的Mac OS X?和Linux?)共同为开发和调试工具。

Qt Creator的主要目标是满足Qt开发人员正在寻找简单，易用性，生产力，可扩展性和开放的发展需要，而旨在降低进入新来乍到Qt的屏障。

Qt Creator 的主要功能，让开发商完成以下任务: , 快速，轻松地开始使用Qt应用开发项目向导，快速访问最近的项目和会议。

, 设计Qt物件为基础的应用与集成的编辑器的用户界面，Qt Designer中。

, 开发与应用的先进的C + +代码编辑器，提供新的强大的功能完成的代码片段，重构代码，查看文件的轮廓(即，象征着一个文件层次)。

, 建立，运行和部署Qt项目，目标多个桌面和移动平台，如微软Windows，Mac OS X中，Linux的，诺基亚的MeeGo，和Maemo。

, GNU和CDB使用Qt类结构的认识，增加了图形用户界面的调试器的调试。

, 使用代码分析工具，以检查你的应用程序中的内存管理问题。

, 应用程序部署到移动设备的MeeGo，为Symbian和Maemo设备创建应用程序安装包，可以在Ovi商店和其他渠道发布的。

, 轻松地访问信息集成的上下文敏感的Qt帮助系统。

中英文对照外文翻译(文档含英文原文和中文翻译)Application FundamentalsAndroid applications are written in the Java programming language. The compiled Java code — along with any data and resource files required by the application — is bundled by the aapt tool into an Android package, an archive file marked by an .apk suffix. This file is the vehicle for distributing the application and installing it on mobile devices; it's the file users download to their devices. All the code in a single .apk file is considered to be one application.In many ways, each Android application lives in its own world:1. By default, every application runs in its own Linux process. Android starts the process when any of the application's code needs to be executed, and shuts down the process when it's no longer needed and system resources are required by other applications.2. Each process has its own virtual machine (VM), so application code runs in isolation from the code of all other applications.3. By default, each application is assigned a unique Linux user ID. Permissions are set so that the application's files are visible only to that user and only to the application itself — although there are ways to export them to other applications as well.It's possible to arrange for two applications to share the same user ID, in which case they will be able to see each other's files. To conserve system resources, applications with the same ID can also arrange to run in the same Linux process, sharing the sameVM.Application ComponentsA central feature of Android is that one application can make use of elements of other applications (provided those applications permit it). For example, if your application needs to display a scrolling list of images and another application has developed a suitable scroller and made it available to others, you can call upon that scroller to do the work, rather than develop your own. Your application doesn't incorporate the code of the other application or link to it. Rather, it simply starts up that piece of the other application when the need arises.For this to work, the system must be able to start an application process when any part of it is needed, and instantiate the Java objects for that part. Therefore, unlike applications on most other systems, Android applications don't have a single entry point for everything in the application (no main() function, for example). Rather, they have essential components that the system can instantiate and run as needed. There are four types of components:ActivitiesAn activity presents a visual user interface for one focused endeavor the user can undertake. For example, an activity might present a list of menu items users can choose from or it might display photographs along with their captions. A text messaging application might have one activity that shows a list of contacts to send messages to, a second activity to write the message to the chosen contact, and other activities to review old messages or change settings. Though they work together to form a cohesive user interface, each activity is independent of the others. Each one is implemented as a subclass of the Activity base class.An application might consist of just one activity or, like the text messaging application just mentioned, it may contain several. What the activities are, and how many there are depends, of course, on the application and its design. Typically, one of the activities is marked as the first one that should be presented to the user when the application is launched. Moving from one activity to another is accomplished by having the current activity start the next one.Each activity is given a default window to draw in. Typically, the window fills the screen, but it might be smaller than the screen and float on top of other windows. An activity can also make use of additional windows — for example, a pop-up dialog that calls for a user response in the midst of the activity, or a window that presents users with vital information when they select a particular item on-screen.The visual content of the window is provided by a hierarchy of views — objects derived from the base View class. Each view controls a particular rectangular space within the window. Parent views contain and organize the layout of their children. Leaf views (those at the bottom of the hierarchy) draw in the rectangles they control and respond to user actions directed at that space. Thus, views are where the activity's interaction with the user takes place.For example, a view might display a small image and initiate an action when the user taps that image. Android has a number of ready-made views that you can use —including buttons, text fields, scroll bars, menu items, check boxes, and more.A view hierarchy is placed within an activity's window by theActivity.setContentView() method. The content view is the View object at the root of the hierarchy. (See the separate User Interface document for more information on views and the hierarchy.)ServicesA service doesn't have a visual user interface, but rather runs in the background for an indefinite period of time. For example, a service might play background music as the user attends to other matters, or it might fetch data over the network or calculate something and provide the result to activities that need it. Each service extends the Service base class.A prime example is a media player playing songs from a play list. The player application would probably have one or more activities that allow the user to choose songs and start playing them. However, the music playback itself would not be handled by an activity because users will expect the music to keep playing even after they leave the player and begin something different. To keep the music going, the media player activity could start a service to run in the background. The system would then keep the music playback service running even after the activity that started it leaves the screen.It's possible to connect to (bind to) an ongoing service (and start the service if it's not already running). While connected, you can communicate with the service through an interface that the service exposes. For the music service, this interface might allow users to pause, rewind, stop, and restart the playback.Like activities and the other components, services run in the main thread of the application process. So that they won't block other components or the user interface, they often spawn another thread for time-consuming tasks (like music playback). See Processes and Threads, later.Broadcast receiversA broadcast receiver is a component that does nothing but receive and react to broadcast announcements. Many broadcasts originate in system code — for example, announcements that the timezone has changed, that the battery is low, that a picture has been taken, or that the user changed a language preference. Applications can also initiate broadcasts — for example, to let other applications know that some data has been downloaded to the device and is available for them to use.An application can have any number of broadcast receivers to respond to any announcements it considers important. All receivers extend the BroadcastReceiver base class.Broadcast receivers do not display a user interface. However, they may start an activity in response to the information they receive, or they may use the NotificationManager to alert the user. Notifications can get the user's attention in various ways — flashing the backlight, vibrating the device, playing a sound, and so on. They typically place a persistent icon in the status bar, which users can open to get the message.Content providersA content provider makes a specific set of the application's data available to other applications. The data can be stored in the file system, in an SQLite database, or in anyother manner that makes sense. The content provider extends the ContentProvider base class to implement a standard set of methods that enable other applications to retrieve and store data of the type it controls. However, applications do not call these methods directly. Rather they use a ContentResolver object and call its methods instead. A ContentResolver can talk to any content provider; it cooperates with the provider to manage any interprocess communication that's involved.See the separate Content Providers document for more information on using content providers.Whenever there's a request that should be handled by a particular component, Android makes sure that the application process of the component is running, starting it if necessary, and that an appropriate instance of the component is available, creating the instance if necessary.Activating components: intentsContent providers are activated when they're targeted by a request from a ContentResolver. The other three components — activities, services, and broadcast receivers — are activated by asynchronous messages called intents. An intent is an Intent object that holds the content of the message. For activities and services, it names the action being requested and specifies the URI of the data to act on, among other things. For example, it might convey a request for an activity to present an image to the user or let the user edit some text. For broadcast receivers, theIntent object names the action being announced. For example, it might announce to interested parties that the camera button has been pressed.There are separate methods for activating each type of component:1. An activity is launched (or given something new to do) by passing an Intent object toContext.startActivity() or Activity.startActivityForResult(). The responding activity can look at the initial intent that caused it to be launched by calling its getIntent() method. Android calls the activity's onNewIntent() method to pass it any subsequent intents. One activity often starts the next one. If it expects a result back from the activity it's starting, it calls startActivityForResult() instead of startActivity(). For example, if it starts an activity that lets the user pick a photo, it might expect to be returned the chosen photo. The result is returned in an Intent object that's passed to the calling activity's onActivityResult() method.2. A service is started (or new instructions are given to an ongoing service) by passing an Intent object to Context.startService(). Android calls the service's onStart() method and passes it the Intent object. Similarly, an intent can be passed to Context.bindService() to establish an ongoing connection between the calling component and a target service. The service receives the Intent object in an onBind() call. (If the service is not already running, bindService() can optionally start it.) For example, an activity might establish a connection with the music playback service mentioned earlier so that it can provide the user with the means (a user interface) for controlling the playback. The activity would call bindService() to set up that connection, and then call methods defined by the service to affect the playback.A later section, Remote procedure calls, has more details about binding to a service.3. An application can initiate a broadcast by passing an Intent object to methods like Context.sendBroadcast(), Context.sendOrderedBroadcast(), andContext.sendStickyBroadcast() in any of their variations.Android delivers the intent to all interested broadcast receivers by calling their onReceive() methods. For more on intent messages, see the separate article, Intents and Intent Filters.Shutting down componentsA content provider is active only while it's responding to a request from a ContentResolver. And a broadcast receiver is active only while it's responding to a broadcast message. So there's no need to explicitly shut down these components. Activities, on the other hand, provide the user interface. They're in a long-running conversation with the user and may remain active, even when idle, as long as the conversation continues. Similarly, services may also remain running for a long time. So Android has methods to shut down activities and services in an orderly way:1. An activity can be shut down by calling its finish() method. One activity can shut down another activity (one it started with startActivityForResult()) by calling finishActivity().2. A service can be stopped by calling its stopSelf() method, or by calling Context.stopService().Components might also be shut down by the system when they are no longer being used or when Android must reclaim memory for more active components. A later section, Component Lifecycles, discusses this possibility and its ramifications in more detail.The manifest fileBefore Android can start an application component, it must learn that the component exists. Therefore, applications declare their components in a manifest file that's bundled into the Android package, the .apk file that also holds the application's code, files, and resources.The manifest is a structured XML file and is always named AndroidManifest.xml for all applications. It does a number of things in addition to declaring the application's components, such as naming any libraries the application needs to be linked against (besides the default Android library) and identifying any permissions the application expects to be granted.But the principal task of the manifest is to inform Android about the application's components. For example, an activity might be declared as follows:The name attribute of the <activity> element names the Activity subclass that implements the activity. The icon and label attributes point to resource files containing an icon and label that can be displayed to users to represent the activity.The other components are declared in a similar way — <service> elements for services, <receiver> elements for broadcast receivers, and <provider> elements for content providers. Activities, services, and content providers that are not declared in the manifest are not visible to the system and are consequently never run. However, broadcast receivers can either be declared in the manifest, or they can be created dynamically in code (as BroadcastReceiver objects) and registered with the system by calling Context.registerReceiver().For more on how to structure a manifest file for your application, see The Android Manifest.xml File.Intent filtersAn Intent object can explicitly name a target component. If it does, Android finds that component (based on the declarations in the manifest file) and activates it. But if a target is not explicitly named, Android must locate the best component to respond to the intent. It does so by comparing the Intent object to the intent filters of potential targets. A component's intent filters inform Android of the kinds of intents the component is able to handle. Like other essential information about the component, they're declared in the manifest file. Here's an extension of the previous example that adds two intent filters to the activity:The first filter in the example — the combination of the action"android.intent.action.MAIN" and the category"UNCHER" — is a common one. It marks the activity as one that should be represented in the application launcher, the screen listing applications users can launch on the device. In other words, the activity is the entry point for the application, the initial one users would see when they choose the application in the launcher.The second filter declares an action that the activity can perform on a particular type of data.A component can have any number of intent filters, each one declaring a different set of capabilities. If it doesn't have any filters, it can be activated only by intents that explicitly name the component as the target.For a broadcast receiver that's created and registered in code, the intent filter is instantiated directly as an IntentFilter object. All other filters are set up in the manifest. For more on intent filters, see a separate document, Intents and Intent Filters.应用程序基础Android DevelopersAndroid应用程序使用Java编程语言开发。

成都理工大学
学生毕业设计（论文）外文译文
图表1展示了FriendTracker和FriendViewer应用所包含的不同类型的组件。

体化了组件。

关于应用中每个类型的组件的数量是没有限制的，但是作为惯例，一个组件与应用有相同的名字。

常见的情况是，这里有个activity，就像在FriendViewer
图表2展示了应用FriendTracker和FriendViewer
android分配的一部分。

在每个案例中，一个组件启动与另一个的通信。

简单来说，我们调用这个内部组件通信（ICC）。

在许多时候，在Unix基础系统中，
ICC的功能除了安全规则以外，同样的是不考虑目标是否在同一个应用或者是不同的应用中。

可用的ICCaction取决于目标组件。

每个类型的组件只特定支持他的类型的交互——举个例子，当
如图表3所示，android通过两个强制机制的共同工作来保护应用和数据，
ICC层面上。

ICC的仲裁定义了核心安全架构，这也是这篇文章的核心，但是他依赖于下层的
系统提供的保障。

（正文页面不够可加页，并在正文后附外文原文，统一用A4纸张打印或手工誊写）。

西安邮电学院毕业设计（论文）外文文献翻译院系：计算机学院专业：软件工程班级：软件0601学生姓名：导师姓名：职称：副教授起止时间：2010年3月8日至2010年6月11日ClassesOne of the most compelling features about Java is code reuse. But to be revolutionary, you’ve got to be able to do a lot more than copy code and change it.That’s the approach used in procedural languages like C, and it hasn’t worked very well. Like everything in Java, the solution revolves around the class. You reuse code by creating new classes, but instead of creating them from scratch, you use existing classes that someone has already built and debugged.The trick is to use the classes without soiling the existing code.➢Initializing the base classSince there are now two classes involved—the base class and the derived class—instead of just one, it can be a bit confusing to try to imagine the resulting object produced by a derived class. From the outside, it looks like the new class has the same interface as the base class and maybe some additional methods and fields. But inheritance doesn’t just copy the interface of the base class. When you create an object of the derived class, it contains within it a subobject of the base class. This subobject is the same as if you had created an object of the base class by itself. It’s just that from the outside, the subobject of the base class is wrapped within the derived-class object.Of course, it’s essential that th e base-class subobject be initialized correctly, and there’s only one way to guarantee this: perform the initialization in the constructor by calling the base-class constructor, which has all the appropriate knowledge and privileges to perform the base-class initialization. Java automatically inserts calls to the base-class constructor in the derived-class constructor.➢Guaranteeing proper cleanupJava doesn’t have the C++ concept of a destructor, a method that is automatically called when an object is destroyed. The reason is probably that in Java, the practice is simply to forget about objects rather than to destroy them, allowing the garbage collector to reclaim the memory as necessary.Often this is fine, but there are times when your class might perform some activities during its lifetime that require cleanup. As mentioned in Chapter 4, you can’t know when the garbage collector will be called, or if it will be called. So if you want something cleaned up for a class, you must explicitly write a special method to do it, and make sure that the client programmer knows that they must call this method.Note that in your cleanup method, you must also pay attention to the calling order for the base-class and member-object cleanup methods in case one subobject depends on another. In general, you should follow the same form that is imposed by a C++ compiler on its destructors: first perform all of the cleanup work specific to your class, in the reverse order of creation. (In general, this requires that base-class elements still be viable.) Then call the base-class cleanup method, as demonstrated here➢Name hidingIf a Java base class has a method name that’s overloaded several times, redefining that method name in the derived class will not hide any of the base-class versions (unlike C++). Thus overloading works regardless of whether the method was defined at this level or in a base class，it’s far more common to override methods of the same name, using exactly the same signature and return type as in the base class. It can be confusing otherwise (which is why C++ disallows it—to prevent you from making what is probably a mistake).➢Choosing composition vs. inheritanceBoth composition and inheritance allow you to place subobjects inside your new class (composition explicitly does this—with inheritance it’s implicit). You might wonder about the difference between the two, and when to choose one over the other.Composition is generally used when you want the features of an existing class inside your new class, but not its interface. That is, you embed an object so that you can use it to implement functionality in your new class, but the user of your new class sees the interface you’ve defined for the new class rather than the interface from theembedded object. For this effect, you embed private objects of existing classes inside your new class.Sometimes it makes sense to allow the class user to directly access the composition of your new class; that is, to make the member objects public. The member objects use implementation hiding themselves, so this is a safe thing to do. When the user knows you’re assembling a bunch of parts, it makes the interface easier to understand.When you inherit, you take an existing class and make a special version of it. In general, this mea ns that you’re taking a general-purpose class and specializing it for a particular need➢The final keywordJava’s final keyword has slightly different meanings depending on the context, but in general it says “This cannot be changed.” You might want to prev ent changes for two reasons: design or efficiency. Because these two reasons are quite different, it’s possible to misuse the final keywordThe following sections discuss the three places where final can be used: for data, methods, and classes.➢Final dataMany programming languages have a way to tell the compiler that a piece of data is “constant.” A constant is useful for two reasons:It can be a compile-time constant that won’t ever change.It can be a value initialized at run time that you don’t want ch anged.In the case of a compile-time constant, the compiler is allowed to “fold” the constant value into any calculations in which it’s used; that is, the calculation can be performed at compile time, eliminating some run-time overhead. In Java, these sorts of constants must be primitives and are expressed with the final keyword. A value must be given at the time of definition of such a constant.A field that is both static and final has only one piece of storage that cannot be changed.When using final with object references rather than primitives, the meaning gets a bit confusing. With a primitive, final makes the value a constant, but with an object reference, final makes the reference a constant. Once the reference is initialized to an object, it can never be changed to point to another object. However, the object itself can be modified; Java does not provide a way to make any arbitrary object a constant. (You can, however, write your class so that objects have the effect of being constant.) This restriction includes arrays, which are also objects.➢Final methodsThere are two reasons for final methods. The first is to put a “lock” on the method to prevent any inheriting class from changing its meaning. This is done for design reasons when you want to mak e sure that a method’s behavior is retained during inheritance and cannot be overridden.The second reason for final methods is efficiency. If you make a method final, you are allowing the compiler to turn any calls to that method into inline calls. When the compiler sees a final method call, it can (at its discretion) skip the normal approach of inserting code to perform the method call mechanism (push arguments on the stack, hop over to the method code and execute it, hop back and clean off the stack arguments, and deal with the return value) and instead replace the method call with a copy of the actual code in the method body. This eliminates the overhead of the method call. Of course, if a method is big, then your code begins to bloat, and you probably won’t see any performance gains from inlining, since any improvements will be dwarfed by the amount of time spent inside the method. It is implied that the Java compiler is able to detect these situations and choose wisely whether to inline a final method. However, it’s best to let the compiler and JVM handle efficiency issues and make a method final only if you want to explicitly prevent overriding➢Final classesWhen you say that an entire class is final (by preceding its definition with the final keyword), you state that you don’t want to inherit from this class or allow anyone else to do so. In other words, for some reason the design of your class is suchthat there is never a need to make any changes, or for safety or security reasons you don’t want subc lassingNote that the fields of a final class can be final or not, as you choose. The same rules apply to final for fields regardless of whet However, because it prevents inheritance, all methods in a final class are implicitly final, since there’s no way to override them. You can add the final specifier to a method in a final class, but it doesn’t add any meaning.her the class is defined as final.➢SummaryBoth inheritance and composition allow you to create a new type from existing types. Typically, however, composition reuses existing types as part of the underlying implementation of the new type, and inheritance reuses the interface. Since the derived class has the base-class interface, it can be upcast to the base, which is critical for polymorphism, as you’ll see in the next chapter.Despite the strong emphasis on inheritance in object-oriented programming, when you start a design you should generally prefer composition during the first cut and use inheritance only when it is clearly necessary. Composition tends to be more flexible. In addition, by using the added artifice of inheritance with your member type, you can change the exact type, and thus the behavior, of those member objects at run time. Therefore, you can change the behavior of the composed object at run time.When designing a system, your goal is to find or create a set of classes in which each class has a specific use and is neither too big (encompassing so much functionality that it’s unwieldy to reuse) nor annoyingly small (you can’t use it by itself or without adding functionality).类“Java引人注目的一项特性是代码的重复使用或者再生。

软件工程本科毕业外文文献翻译学校代码：10128本科毕业设计外文文献翻译二〇一五年一月The Test Library Management System ofFramework Based on SSHThe application system features in small or medium-sized enterprise lie in the greater flexibility and safety high performance-price ratio. Traditional J2EE framework can not adapt to these needs, but the system a pplication based on SSH(Struts+Spring+Hibernate) technology can better satisfy such needs. This paper analyses some integration theory and key technologies about SSH, and according to the integration constructs a lightweight WEB framework, which has integrated the three kinds of technology ,forming the lightweight WEB framework bas ed on SSH and gaining good effects in practical applications.IntroductionGenerally the J2EE platform[27] used in large enterprise applications, can well s olve the application of reliability, safety and stability, but its weakness is the price hig h and the constructing cycle is long. Corresponding to the small or medium enterprise applications, the replace approach is the system framework of lightweight WEB, inclu ding the more commonly used methods which are based on the Struts and Hibernate. With the wide application of Spring, the three technology combination may be a bette r choice as a lightweight WEB framework. It uses layered structure and provides a go od integrated framework for Web applications at all levels in minimizing the Interlaye r coupling and increasing the efficiency of development. This framework can solve a l ot of problems, with good maintainability and scalability. It can solve the separation o f user interface and business logic separation, the separation of business logic and data base operation and the correct procedure control logic, etc. This paper studies the tech nology and principle of Struts and Spring and Hibernate, presenting a proved lightwei ght WEB application framework for enterprise.Hierarchical Web MechanismHierarchical Web framework including the user presentation layer, business logi clayer, data persistence layer ,expansion layer etc, each layer for different function, re spectively to finish the whole application. The whole system are divided into differentlogic module with relatively independent and mutual, and each module can be imple mented according to different design. It can realize the system parallel development, r apid integration, good maintainability, scalability.Struts MVC FrameworkTo ensure the reuse and efficiency of development process, adopting J2EE techn ology to build the Web application must select a system framework which has a good performance . Only in this way can we ensure not wasting lots of time because of adju sting configuration and achieve application development efficiently and quickly. So, p rogrammers in the course of practice got some successful development pattern which proved practical, such as MVC and O/R mapping, etc; many technologies, including S truts and Hibernate frameworks, realized these pattern. However, Struts framework on ly settled the separation problem between view layer and business logic layer, control layer, did not provide a flexible support for complex data saving process. On the contr ary, Hibernate framework offered the powerful and flexible support for complex data saving process. Therefore, how to integrate two frameworks and get a flexible, low-coupling solutions project which is easy to maintain for information system, is a resea rch task which the engineering staff is studying constantly.Model-View-Controller (MVC) is a popular design pattern. It divides the interactive system in three components and each of them specializes in one task. The model contains the applica tion data and manages the core functionality. The visual display of the model and the f eedback to the users are managed by the view. The controller not only interprets the in puts from the user, but also dominates the model and the view to change appropriately . MVC separates the system functionality from the system interface so as to enhance t he system scalability and maintainability. Struts is a typical MVC frame[32], and it also contains the three aforementioned components. The model level is composed of J avaBean and EJB components. The controller is realized by action and ActionServlet, and the view layer consists of JSP files. The central controller controls the action exec ution that receives a request and redirects this request to the appropriate module contr oller. Subsequently, the module controller processes the request and returns results tothe central controller using a JavaBean object, which stores any object to be presented in the view layer by including an indication to module views that must be presented. The central controller redirects the returned JavaBean object to the main view that dis plays its information.Spring Framework technologySpring is a lightweight J2EE application development framework, which uses the model of Inversion of Control(IoC) to separate the actual application from the Config uration and dependent regulations of the application. Committed to J2EE application a t all levels of the solution, Spring is not attempting to replace the existing framework, but rather “welding” the object of J2EE application at all levels together through the P OJO management. In addition, developers are free to choose Spring framework for so me or all, since Spring modules are not totally dependent.As a major business-level detail, Spring employs the idea of delay injection to assemble code for the sake o f improving the scalability and flexibility of built systems. Thus, the systems achieve a centralized business processing and reduction of code reuse through the Spring AOP module.Hibernate Persistent FrameworkHibernate is a kind of open source framework with DAO design patterns to achie ve mapping(O/R Mapping) between object and relational database.During the Web system development, the tradition approach directly interacts wi th the database by JDBC .However, this method has not only heavy workload but also complex SQL codes of JDBC which need to revise because the business logic sli ghtly changes. So, whatever development or maintain system are inconvenient. Consi dering the large difference between the object-oriented relation of java and the structure of relational database, it is necessary to intro duce a direct mapping mechanism between the object and database, which this kind of mapping should use configuration files as soon as possibility, so that mapping files w ill need modifying rather than java source codes when the business logic changes in the future. Therefore, O/R mapping pattern emerges, which hibernate is one of the most outstanding realization of architecture.It encapsulates JDBC with lightweight , making Java programmer operate a relati onal database with the object oriented programming thinking. It is a a implementation technology in the lasting layer. Compared to other lasting layer technology such as JD BC, EJB, JDO, Hibernate is easy to grasp and more in line with the object-oriented programming thinking. Hibernate own a query language (HQL), which is full y object-oriented. The basic structure in its application as shown in figure6.1.Hibernate is a data persistence framework, and the core technology is the object / relational database mapping(ORM). Hibernate is generally considered as a bridge bet ween Java applications and the relational database, owing to providing durable data se rvices for applications and allowing developers to use an object-oriented approach to the management and manipulation of relational database. Further more, it furnishes an object-oriented query language-HQL.Responsible for the mapping between the major categories of Java and the relatio nal database, Hibernate is essentially a middle ware providing database services. It su pplies durable data services for applications by utilizing databases and several profiles , such as hibernate properties and XML Mapping etc..Web services technologiesThe introduction of annotations into Java EE 5 makes it simple to create sophisticated Web service endpoints and clients with less code and a shorter learning curve than was possible with earlier Java EE versions. Annotations — first introduced in Java SE 5 — are modifiers you can add to your code as metadata. They don't affect program semantics directly, but the compiler, development tools, and runtime libraries can process them to produce additional Java language source files, XML documents, or other artifacts and behavior that augment the code containing the annotations (see Resources). Later in the article, you'll see how you can easily turn a regular Java class into a Web service by adding simple annotations.Web application technologiesJava EE 5 welcomes two major pieces of front-end technology — JSF and JSTL — into the specification to join the existing JavaServer Pages and Servlet specifications. JSF is a set of APIs that enable a component-based approach to user-interface development. JSTL is a set of tag libraries that support embedding procedural logic, access to JavaBeans, SQL commands, localized formatting instructions, and XML processing in JSPs. The most recent releases of JSF, JSTL, and JSP support a unified expression language (EL) that allows these technologies to integrate more easily (see Resources).The cornerstone of Web services support in Java EE 5 is JAX-WS 2.0, which is a follow-on to JAX-RPC 1.1. Both of these technologies let you create RESTful and SOAP-based Web services without dealing directly with the tedium of XML processing and data binding inherent to Web services. Developers are free to continue using JAX-RPC (which is still required of Java EE 5 containers), but migrating to JAX-WS is strongly recommended. Newcomers to Java Web services might as well skip JAX-RPC and head right for JAX-WS. That said, it's good to know that both of them support SOAP 1.1 over HTTP 1.1 and so are fully compatible: a JAX-WS Web services client can access a JAX-RPC Web services endpoint, and vice versa.The advantages of JAX-WS over JAX-RPC are compelling. JAX-WS:•Supports the SOAP 1.2 standard (in addition to SOAP 1.1).•Supports XML over HTTP. You can bypass SOAP if you wish. (See the article "Use XML directly over HTTP for Web services (where appropriate)"for more information.)•Uses the Java Architecture for XML Binding (JAXB) for its data-mapping model. JAXB has complete support for XML schema and betterperformance (more on that in a moment).•Introduces a dynamic programming model for both server and client.The client model supports both a message-oriented and an asynchronous approach.•Supports Message Transmission Optimization Mechanism (MTOM), a W3C recommendation for optimizing the transmission and format of a SOAP message.•Upgrades Web services interoperability (WS-I) support. (It supports Basic Profile 1.1; JAX-WS supports only Basic Profile 1.0.)•Upgrades SOAP attachment support. (It uses the SOAP with Attachments API for Java [SAAJ] 1.3; JAX-WS supports only SAAJ 1.2.)•You can learn more about the differences by reading the article "JAX-RPC versus JAX-WS."The wsimport tool in JAX-WS automatically handles many of the mundane details of Web service development and integrates easily into a build processes in a cross-platform manner, freeing you to focus on the application logic that implements or uses a service. It generates artifacts such as services, service endpoint interfaces (SEIs), asynchronous response code, exceptions based on WSDL faults, and Java classes bound to schema types by JAXB.JAX-WS also enables high-performing Web services. See Resources for a link to an article ("Implementing High Performance Web Services Using JAX-WS 2.0") presenting a benchmark study of equivalent Web service implementations based on the new JAX-WS stack (which uses two other Web services features in Java EE 5 —JAXB and StAX) and a JAX-RPC stack available in J2EE 1.4. The study found 40% to 1000% performance increases with JAX-WS in various functional areas under different loads.ConclusionEach framework has its advantages and disadvantages .Lightweight J2EE struct ure integrates Struts and Hibernate and Spring technology, making full use the powerf ul data processing function of Struts and the management flexible of Spring and the m ature of Hibernate. According to the practice, putting forward an open-source solutions suitable for small or medium-sized enterprise application of. The application system based on this architecture tech nology development has interlayer loose coupling ,structure distinctly, short develop ment cycle, maintainability. In addition, combined with commercial project developm ent, the solution has achieved good effect. The lightweight framework makes the paral lel development and maintenance for commercial system convenience, and can push f orward become other industry business system development.Through research and practice, we can easily find that Struts / Spring / Hiberna te framework utilizes Struts maturity in the presentation layer, flexibility of Spring bu siness management and convenience of Hibernate in the serialization layer, three kind s of framework integrated into a whole so that the development and maintenance beca me more convenient and handy. This kind of approach also will play a key role if appl ying other business system. Of course ,how to optimize system performance, enhance the user's access speed, improve security ability of system framework ,all of these wor ks, are need to do for author in the further.基于SSH框架实现的试题库管理系统小型或者中型企业的应用系统具有非常好的灵活性、安全性以及高性价比，传统的J2EE架构满足不了这些需求，但是基于SSH框架实现的应用系统更好的满足了这样的需求，这篇文章分析了关于SSH的一体化理论和关键技术，通过这些集成形成了轻量级Web框架，在已经集成三种技术的基础上，伴随形成了基于SSH的轻量级Web 框架，并且在实际应用中有着重要作用。

（二〇一三年六月A HISTORICAL PERSPECTIVEFrom the earliest days of computers, storing and manipulating data a major application focus. The first general-purpose DBMS was designed by Charles Bachman at General Electric in the early 1960s and was called the Integrated Data Store. It formed the basis for the network data model, which was standardized by the Conference on Data Systems Languages (CODASYL) and strongly influenced database systems through the 1960s. Bachman was the fi rst recipient of ACM’s Turing Award (the computer science equivalent of a Nobel prize) for work in the database area; 1973. In the late 1960s, IBM developed the Information Management System (IMS) DBMS, used even today in many major installations. IMS formed the basis for an alternative data representation framework called the Airlines and IBM around the same time, and it allowed several people to access the same data through computer network. Interestingly, today the same SABRE system is used to power popular Web-based travel services such as Travelocity!In 1970, Edgar Codd, at IBM’s San Jose Research Laboratory, proposed a new data representation framework called the relational data model. This proved to be a watershed in the development of database systems: it sparked rapid development of several DBMSs based on the relational model, along with a rich body of theoretical results that placed the field on a firm foundation. Codd won the 1981 Turing Award for academic discipline, and the popularity of relational DBMSs changed thecommercial landscape. Their benefits were widely recognized, and the use of DBMSs for managing corporate data became standard practice.In the 1980s, the relational model consolidated its position as the dominant DBMS paradigm, and database systems continued to gain widespread use. The SQL query language for relational databases, developed as part of IBM’s System R project, is now the standard query language. SQL was standardized in the late 1980s, and the current standard, SQL-92, was adopted by the American National Standards Institute (ANSI) and International Standards Organization (ISO). Arguably, the most widely used form of concurrent programming is the concurrent execution of database programs (called transactions). Users write programs as if they are to be run by themselves, and the responsibility for running them concurrently is given to the DBMS. James Gray won the 1999 Turing award for management in a DBMS.In the late 1980s and the 1990s, advances made in many areas of database systems. Considerable research carried out into more powerful query languages and richer data models, and there a big emphasis on supporting complex analysis of data from all parts of an enterprise. Several vendors (e.g., IBM’s DB2, Oracle 8, Informix UDS) developed by numerous vendors for creating data warehouses, consolidating data from several databases, and for carrying out specialized analysis.An interesting phenomenon is the emergence of several enterprise resource planning(ERP) and management resource planning (MRP) packages, which add a substantial layer of application-oriented features on top of a DBMS. Widely used packages include systems from Baan, Oracle,PeopleSoft, SAP, and Siebel. These packages identify a set of common tasks (e.g., inventory management, resources planning, financial analysis) encountered by a large number of organizations and provide a general application layer to carry out these tasks. The data is stored in a relational DBMS, and the application layer can be customized to different companies, leading to lower Introduction to Database Systems overall costs for the companies, compared to the cost of building the application layer from scratch. Most significantly, perhaps, DBMSs of Web sites stored their data exclusively in operating systems files, the use of a DBMS to store data that is accessed through a Web browser is becoming widespread. Queries are generated through Web-accessible forms and answers are formatted using a markup language such as HTML, in order to be easily displayed in a browser. All the database vendors are adding features to their DBMS aimed at making it more suitable for deployment over the Internet. Database management continues to gain importance as more and more data is brought on-line, and made ever more accessible through computer networking. Today the field is being driven by exciting visions such as multimedia databases, interactive video, digital libraries, a genome mapping effort and NASA’s Earth Observation System project,and the desire of companies to consolidate their decision-making processes and mine their data repositories for useful information about their businesses. Commercially, database manage- ment systems represent one of the largest and most vigorous market segments. Thusthes- tudy of database systems could prove to be richly rewarding in more ways than one!INTRODUCTION TO PHYSICAL DATABASEDESIGNLike all other aspects of database design, physical design must be guided by the nature of the data and its intended use. In particular, it is important to understand the typical workload that the database must support; the workload consists of a mix of queries and updates. Users also requirements about queries or updates must run or and users’ performance requirements are the basis on which a number of decisions .To create a good physical database design and to tune the system for performance in response to evolving user requirements, the designer needs to understand the workings of a DBMS, especially the indexing and query processing techniques supported by the DBMS. If the database is expected to be accessed concurrently by many users, or is a distributed database, the task becomes more complicated, and other features of a DBMS come into play.DATABASE WORKLOADSThe key to good physical design is arriving at an accurate description of the expected workload. A workload description includes the following elements:1. A list of queries and their frequencies, as a fraction of all queries and updates.2. A list of updates and their frequencies.3. Performance goals for each type of query and update.For each query in the workload, we must identify:Which relations are accessed.Which attributes are retained (in the SELECT clause).Which attributes or join conditions expressed on them (in the WHERE clause) and the workload, we must identify:Which attributes or join conditions expressed on them (in the WHERE clause) and .For UPDATE commands, the fields that are modified by the update.Remember that queries and updates typically involves a particular account number. The values of these parameters determine selectivity of selection and join conditions.Updates benefit from a good physical design and the presence of indexes. On the other indexes on the attributes that they modify. Thus, while queries can only benefit from the presence of an index, an index may either speed up or slow down a given update. Designers should keep this trade-offer in mind when creating indexes.NEED FOR DATABASE TUNINGAccurate, detailed workload information may be of the system. Consequently, tuning a database after it designed and deployed is important—we must refine the initial design in the light of actual usage patterns to obtain the best possible performance.The distinction between database design and database tuning is somewhat arbitrary.We could consider the design process to be over once an initial conceptual schema is designed and a set of indexing and clustering decisions is made. Any subsequent changes to the conceptual schema or the indexes, say, would then be regarded as a tuning activity. Alternatively, we could consider some refinement of the conceptual schema (and physical design decisions affected by this refinement) to be part of the physical design process.Where we draw the line between design and tuning is not very important.OVERVIEW OF DATABASE TUNINGAfter the initial phase of database design, actual use of the database provides a valuable source of detailed information that can be used to refine the initial design. Many of the original assumptions about the expected workload can be replaced by observed usage patterns; in general, some of the initial workload specification will be validated, and some of it will turn out to be wrong. Initial guesses about the size of data can be replaced with actual statistics from the system catalogs (although this information will keep changing as the system evolves). Careful monitoring of queries can reveal unexpected problems; for example, the optimizer may not be using some indexes as intended to produce good plans.Continued database tuning is important to get the best possibleperformance.TUNING THE CONCEPTUAL SCHEMAIn the course of database design, we may realize that our current choice of relation schemas does not enable us meet our performance objectives for the given workload with any (feasible) set of physical design choices. If so, we may our conceptual schema (and re-examine physical design decisions that are affected by the changes that we make).We may realize that a redesign is necessary during the initial design process or later, after the system in use for a while. Once a database designed and populated with data, changing the conceptual schema requires a significant effort in terms of mapping the contents of relations that are affected. Nonetheless, it may sometimes be necessary to revise the conceptual schema in light of experience with the system. We now consider the issues involved in conceptual schema (re)design from the point of view of performance.Several options must be considered while tuning the conceptual schema:We may decide to settle for a 3NF design instead of a BCNF design.If there are two ways to decompose a given schema into 3NF or BCNF, our choice should be guided by the workload.Sometimes we might decide to further decompose a relation that is already in BCNF.In other situations we might denormalize. That is, we might choose toreplace a collection of relations obtained by a decomposition from a larger relation with the original (larger) relation, even though it suffers from some redundancy problems. Alternatively, we might choose to add some fields to certain relations to speed up some important queries, even if this leads to a redundant storage of some information (and consequently, a schema that is in neither 3NF nor BCNF).This discussion of normalization the technique of decomposition, which amounts to vertical partitioning of a relation. Another technique to consider is , which would lead to our ; rather, we want to create two distinct relations (possibly with different constraints and indexes on each).Incidentally, when we redesign the conceptual schema, especially if we are tuning an existing database schema, it is worth considering whether we should create views to mask these changes from users for whom the original schema is more natural.TUNING QUERIES AND VIEWSIf we notice that a query is running much slower than we expected, we conjunction with some index tuning, can often ?x the problem. Similar tuning may be called for if queries on some view run slower than expected.When tuning a query, the first thing to verify is that the system is using the plan that you expect it to use. It may be that the system is not finding the best plan for a variety of reasons. Some common situations that are not condition involving null values.Selection conditions involving arithmetic or string expressions orconditions using the or connective. For example, if we E.age = 2*D.age in the WHERE clause, the optimizer may correctly utilize an available index on E.age but fail to utilize an available index on D.age. Replacing the condition by E.age2=D.age would reverse the situation.Inability to recognize a sophisticated plan such as an index-only scan for an aggregation query involving a GROUP BY clause.If the optimizer is not smart enough to and the best plan (using access methods and evaluation strategies supported by the DBMS), some systems allow users to guide the choice of a plan by providing order and join method. A user who wishes to guide optimization in this manner should and the capabilities of the given DBMS.(8)OTHER TOPICSMOBILE DATABASESThe availability of portable computers and wireless communications many components of a DBMS, including the query engine, transaction manager, and recovery manager.Users are connected through a wireless link whose bandwidth is ten times less than Ethernet and 100 times less than ATM networks. Communication costs are therefore significantly proportion to IO and CPU costs.Users’ locati ons are constantly changing, and mobile computers costs is connection time and battery usage in addition to bytes transferred, and change constantly depending on location. Data is frequently replicated to minimize the cost of accessing it from different locations.As a user moves around, data could be accessed from multipledatabase servers within a single transaction. The likelihood of losing connections is also much greater than in a traditional network. Centralized transaction management may therefore be impractical, especially if some data is resident at the mobile computers. We may in fact ACID transactions and develop alternative notions of consistency for user programs.MAIN MEMORY DATABASESThe price of main memory is now low enough that we can buy enough main memory to CPUs also memory. This shift prompts a reexamination of some basic DBMS design decisions, since disk accesses no longer dominate processing time for a memory-resident database: Main memory does not survive system crashes, and so we still atomicity and durability. Log records must be written to stable storage at commit time, and this process could become a bottleneck. To minimize this problem, rather than commit each transaction as it completes, we can collect completed transactions and commit them in batches; this is called group commit. Recovery algorithms can also be optimized since pages rarely out to make room for other pages.The implementation of in-memory operations must be considered while optimizing queries, namely the amount of space required to execute a plan. It is important to minimize the space overhead because exceeding available physical memory would lead to swapping pages to disk (through the operating system’s virtual memory mechanisms), greatly slowing down execution.Page-oriented data structures become less important (since pages areno longer the unit of data retrieval), and clustering is not important (since the cost of accessing any region of main memory is uniform).（一）从历史的角度回顾从数据库的早期开始，存储和操纵数据就一直是主要的应用焦点。

软件工程外文翻译文献(文档含中英文对照即英文原文和中文翻译)Software engineeringSoftware engineering is the study of the use of engineering methods to build and maintain effective, practical and high-quality software disciplines. It involves the programming language, database, software development tools, system platform, standards, design patterns and so on.In modern society, the software used in many ways. Typical software such as email, embedded systems, human-machine interface, office packages, operating systems, compilers, databases, games. Meanwhile, almost all the various sectors of computer software applications, such as industry, agriculture, banking, aviation and government departments. These applications facilitate the economic and social development,improve people's working efficiency, while improving the quality of life. Software engineers is to create software applications of people collectively, according to which software engineers can be divided into different areas of system analysts, software designers, system architects, programmers, testers and so on. It is also often used to refer to a variety of software engineers, programmers.OriginIn view of difficulties encountered in software development, North Atlantic Treaty Organization (NATO) in 1968 organized the first Conference on Software Engineering, and will be presented at the "software engineering" to define the knowledge required for software development, and suggested that "software development the activities of similar projects should be. " Software Engineering has formally proposed since 1968, this time to accumulate a large number of research results, widely lot of technical practice, academia and industry through the joint efforts of software engineering is gradually developing into a professional discipline.Definitioncreation and use of sound engineering principles in order to obtain reliable and economically efficient software.application of systematic, follow the principle can be measured approach to development, operation and maintenance of software; that is to beapplied to software engineering.The development, management and updating software products related to theories, methods and tools.A knowledge or discipline (discipline), aims to produce good quality, punctual delivery, within budget and meet users need software.the practical application of scientific knowledge in the design, build computer programs, and the accompanying documents produced, and the subsequent operation and maintenance.Use systematic production and maintenance of software products related to technology and management expertise to enable software development and changes in the limited time and under cost.Construction team of engineers developed the knowledge of large software systems disciplines.the software analysis, design, implementation and maintenance of a systematic method.the systematic application of tools and techniques in the development of computer-based applications.Software Engineering and Computer ScienceSoftware development in the end is a science or an engineering, this is a question to be debated for a long time. In fact, both the two characteristics of software development. But this does not mean that they can be confused with each other. Many people think that softwareengineering, computer science and information science-based as in the traditional sense of the physical and chemical engineering as. In the U.S., about 40% of software engineers with a degree in computer science. Elsewhere in the world, this ratio is also similar. They will not necessarily use every day knowledge of computer science, but every day they use the software engineering knowledge.For example, Peter McBreen that software "engineering" means higher degree of rigor and proven processes, not suitable for all types of software development stage. Peter McBreen in the book "Software Craftsmanship: The New Imperative" put forward the so-called "craftsmanship" of the argument, consider that a key factor in the success of software development, is to develop the skills, not "manufacturing" software process.Software engineering and computer programmingSoftware engineering exists in a variety of applications exist in all aspects of software development. The program design typically include program design and coding of the iterative process, it is a stage of software development.Software engineering, software project seeks to provide guidance in all aspects, from feasibility analysis software until the software after completion of maintenance work. Software engineering that software development and marketing activities are closely related. Such assoftware sales, user training, hardware and software associated with installation. Software engineering methodology that should not be an independent programmer from the team and to develop, and the program of preparation can not be divorced from the software requirements, design, and customer interests.Software engineering design of industrial development is the embodiment of a computer program.Software crisisSoftware engineering, rooted in the 20th century to the rise of 60,70 and 80 years of software crisis. At that time, many of the software have been a tragic final outcome. Many of the software development time significantly beyond the planned schedule. Some projects led to the loss of property, and even some of the software led to casualties. While software developers have found it increasingly difficult for software development.OS 360 operating system is considered to be a typical case. Until now, it is still used in the IBM360 series host. This experience for decades, even extremely complex software projects do not have a set of programs included in the original design of work systems. OS 360 is the first large software project, which uses about 1,000 programmers. Fred Brooks in his subsequent masterpiece, "The Mythical Man Month" (The Mythical Man-Month) in the once admitted that in his management of theproject, he made a million dollar mistake.Property losses: software error may result in significant property damage. European Ariane rocket explosion is one of the most painful lesson.Casualties: As computer software is widely used, including hospitals and other industries closely related to life. Therefore, the software error might also result in personal injury or death.Was used extensively in software engineering is the Therac-25 case of accidents. In 1985 between June and January 1987, six known medical errors from the Therac-25 to exceed the dose leads to death or severe radiation burns.In industry, some embedded systems do not lead to the normal operation of the machine, which will push some people into the woods. MethodologyThere are many ways software engineering aspects of meaning. Including project management, analysis, design, program preparation, testing and quality control.Software design methods can be distinguished as the heavyweight and lightweight methods. Heavyweight methods produce large amounts of official documentation.Heavyweight development methodologies, including the famous ISO 9000, CMM, and the Unified Process (RUP).Lightweight development process is not an official document of the large number of requirements. Lightweight methods, including well-known Extreme Programming (XP) and agile process (Agile Processes).According to the "new methodology" in this article, heavyweight method presented is a "defensive" posture. In the application of the "heavyweight methods" software organizations, due to a software project manager with little or no involvement in program design, can not grasp the item from the details of the progress of the project which will have a "fear", constantly had to ask the programmer to write a lot of "software development documentation." The lightweight methods are presented "aggressive" attitude, which is from the XP method is particularly emphasized four criteria - "communication, simplicity, feedback and courage" to be reflected on. There are some people that the "heavyweight method" is suitable for large software team (dozens or more) use, and "lightweight methods" for small software team (a few people, a dozen people) to use. Of course, on the heavyweight and lightweight method of approach has many advantages and disadvantages of debate, and various methods are constantly evolving.Some methodologists think that people should be strictly followed in the development and implementation of these methods. But some people do not have the conditions to implement these methods. In fact, themethod by which software development depends on many factors, but subject to environmental constraints.Software development processSoftware development process, with the subsequent development of technology evolution and improvement. From the early waterfall (Waterfall) development model to the subsequent emergence of the spiral iterative (Spiral) development, which recently began the rise of agile development methodologies (Agile), they showed a different era in the development process for software industry different awareness and understanding of different types of projects for the method.Note distinction between software development process and software process improvement important difference between. Such as ISO 15504, ISO 9000, CMM, CMMI such terms are elaborated in the framework of software process improvement, they provide a series of standards and policies to guide software organizations how to improve the quality of the software development process, the ability of software organizations, and not give a specific definition of the development process.Development of software engineering"Agile Development" (Agile Development) is considered an important software engineering development. It stressed that software development should be able to possible future changes and uncertaintiesof a comprehensive response.Agile development is considered a "lightweight" approach. In the lightweight approach should be the most prestigious "Extreme Programming" (Extreme Programming, referred to as XP).Correspond with the lightweight approach is the "heavyweight method" exists. Heavyweight approach emphasizes the development process as the center, rather than people-centered. Examples of methods such as heavyweight CMM / PSP / TSP.Aspect-oriented programming (Aspect Oriented Programming, referred to as the AOP) is considered to software engineering in recent years, another important development. This aspect refers to the completion of a function of a collection of objects and functions. In this regard the contents related to generic programming (Generic Programming) and templates.软件工程软件工程是一门研究用工程化方法构建和维护有效的、实用的和高质量的软件的学科。

软件工程外文文献翻译大连交通大学2012届本科生毕业设计 (论文) 外文翻译原文:New Competencies for HRWhat does it take to make it big in HR? What skills and expertise do you need? Since 1988, Dave Ulrich, professor of business administration at the University of Michigan, and his associates have been on a quest to provide the answers. This year, they?ve released an all-new 2007 Human Resource Competency Study (HRCS). Thefindings and interpretations lay out professional guidance for HRfor at least the next few years.“People want to know what set of skills high-achieving HR people need toperform even better,” says Ulrich, co-director of the project along with WayneBrockbank, also a professor of business at the University of Michigan.Conducted under the auspices of the Ross School of Business at the University of Michigan and The RBL Group in Salt Lake City, with regional partners including the Society for Human Resource Management (SHRM) in North America and other institutions in Latin America, Europe, China and Australia, HRCS is the longest-running, most extensive global HR competency study in existence. “Inreaching our conclusions, we?ve looked across more than 400 companies and are able to report with statistical accuracy what HR executives say and do,” Ulrich says.“The re search continues to demonstrate the dynamic nature of the humanresource management profession,” says SHRM President and CEO Susan R. Meisinger, SPHR. “The findings also highlight what an exciting time it is to be in the profession. We continue to have the ability to really add value to an organization.”“HRCS is foundational work that is really important to HR as a profession,” says Cynthia McCague, senior vice president of the Coca-Cola Co., who participated in the study. “They have created and continue to enhance a framework for thinking about how HR drives organizational performance.”What’s NewResearchers identified six core competencies that high-performing HR professionals embody. These supersede the five competencies outlined in the 2002 HRCS—the last study published—reflecting the continuing evolution of the HRprofession. Each competency is broken out into performance elements.“This is the fifth round, so we can look at past models and compare where the profession is going,” says Evren Esen, survey program manager at SHRM, which provided the sample of HR professionals surveyed in NorthAmerica. “We can actually see the profession changing. Some core areas remain the same, but others,大连交通大学2012届本科生毕业设计 (论文) 外文翻译based on how the raters asse ss and perceive HR, are new.” (For more information, see “The Competencies and Their Elements,” at right.) To some degree, the new competencies reflect a change in nomenclature or a shuffling of the competency deck. However, there are some key differences.Five years ago, HR?s role in managing culture was embedded within a broadercompetency. Now its importance merits a competency of its own. Knowledge of technology, a stand-alone competency in 2002, now appears within Business Ally. In other instances, the new competencies carry expectations that promise to change the way HR views its role. For example, the Credible Activist calls for HR to eschew neutrality and to take a stand—to practice the craft “with an attitude.”To put the competencies in perspective, it?s helpful to view them as a three-tierpyramid with Credible Activist at the pinnacle.Credible Activist. This competency is the top indicator inpredicting overall outstanding performance, suggesting that mastering it should be a priority. “You?ve got to be good at all of them, but, no question, [this competency] is key,” Ulrich says.“But you can?t be a Credible Activist without having all the other competencies. In a sense, it?s the whole package.”“It?s a deal breaker,” agrees Dani Johnson, project manager of the Human Resource Competency Study at The RBL Group in Salt Lake City. “If you don?t cometo the table with it, you?re done. It permeates everything you do.”The Credible Activist is at the heart of what it takes to be an effective H R leader. “The best HR people do not hold back; they step forward and advocate for theirposition,” says Susan Harmansky, SPHR, senior director of domestic restaurant operations for HR at Papa John?s International in Louisville, Ky., and former chair of the Human Resource Certification Institute. “CEOs are not waiting for HR to come in with options—they want your recommendations; they want you to speak from your position as an expert, similar to what you see from legal or finance executives.”“You don?t w ant to be credible without being an activist, because essentially you?re worthless to the business,” Johnson says. “People like you, but you have no impact. On the other hand, you don?t want to be an activist without being credible. You can be dangerous in a situation like that.”Below Credible Activist on the pyramid is a cluster of three competencies: Cultural Steward, Talent Manager/Organizational Designer and Strategy Architect.Cultural Steward. HR has always owned culture. But with Sarbanes-Oxley and other regulatory pressures, and CEOs relying more on HR to manage culture, this is the first time it has emerged as an independent competency. Of the six competencies,大连交通大学2012届本科生毕业设计 (论文) 外文翻译Cultural Steward is the second highest predictor of performance of both HR professionals and HR departments.Talent Manager/Organizational Designer. Talent management focuses on howindividuals enter, move up, across or out of the organization. Organizational design centers on the policies, practices and structure that shape how the organization works. Their linking reflects Ulrich?s belief that HR may be placing too much emphasis ontalent acquisition at the expense of organizational design. Talent management will not succeed in the long run without an organizational structure that supports it.Strategy Architect. Strategy Architects are able to recognize business trends and their impact on the business, and to identify potential roadblocks and opportunities. Harmansky, who recently joined Papa John?s, demonstrates how the Strategy Architect competency helps HR contribute to the overall business strategy. “In my first months here, I?m spending a lot of time traveling, going to see stores all over the country. Every time I go to a store, while my counterparts of the management team are talking about [operational aspects], I?m talking tothe people who work there. I?m trying to find out what the issues are surrounding people. How do I develop them? I?m looking for my business differentiator on the people side s o I can contribute to the strategy.”When Charlease Deathridge, SPHR, HR manager of McKee Foods inStuarts Draft, Va., identified a potential roadblock to implementing a new management philosophy, she used the Strategy Architect competency. “When we were rolling out …lean manufacturing? principles at our location, we administered an employee satisfaction survey to assess how the workers viewed the new system. The satisfaction scores were lower than ideal. I showed [management] how a negative could become a positive, how we could use the data and follow-up surveys as a strategic tool to demonstrate progress.”Anchoring the pyramid at its base are two competencies that Ulrich describes as “table stakes—necessary but not sufficient.” Except in China, where HR is at an earlier stage in professional development and there is great emphasis on transactional activities, these competencies are looked upon as basic skills that everyone must have. There is some disappointing news here. In the United States, respondents rated significantly lower on these competencies than the respondents surveyedin other countries.Business Ally. HR contributes to the success of a business byknowing how it makes money, who the customers are, and why they buy the company?s products and services. For HR professionals to be BusinessAllies (and Credible Activists and Strategy Architects as well), they should be what Ulrich describes as “businessliterate.” The mantra about understanding the business—how it works, the financialsand strategic issues—remains as important today as it did in every iteration of the survey the past 20 years. Yet progress in this area continues to lag.大连交通大学2012届本科生毕业设计 (论文) 外文翻译“Even these high performers don?t know the business as well as they should,” U lrich says. In his travels, he gives HR audiences 10 questions to test their business literacy.Operational Executor. These skills tend to fall into the range of HR activities characterized as transactional or “legacy.” Policies need to be drafted, adapted and implemented. Employees need to be paid, relocated, hired, trained and more. Every function here is essential, but—as with the Business Allycompetency—high-performing HR managers seem to view them as less important and score higher on the other competencies. Even some highly effective HR people may be running a risk in paying too little attention to these nuts-and-bolts activities, Ulrich observes.Practical ToolIn conducting debriefings for people who participated in the HRCS, Ulrich observes how delighted they are at the prescriptive nature of theexercise. The individual feedback reports they receive (see “How the Study Was Done”) offer thema road map, and they are highly motivated to follow it.Anyone who has been through a 360-degree appraisal knows that criticism can be jarring. It?s risky to open yourself up to others? opinions when you don?t have to. Add the prospect of sharing the results with your boss and colleagues who will be rating you, and you may decide to pass. Still, it?s not surprising that highly motivated people like Deathridge jumped at the chance for the free feedback.“All of it is not good,” says Deathridge. “You have to be willing to face up to it. You go home, work it out and say, …Why am I getting this bad feedback?? ”But for Deathridge, the results mostly confirmed what she already knew. “Ibelieve most people know where they?re weak or strong. For me, it was most helpful to look at how close others? ratings of me matched with my own assessments. ... There?s so much to learn about what it takes to be a genuine leader, and this studyhelped a lot.”Deathridge says the individual feedback report she received helped her realize the importance of taking a stand and developing her Credible Activist competency. “There wa s a situation where I had a line manager who wanted to disciplinesomeone,” she recalls. “In the past, I wouldn?t have been able to stand up as strongly as I did. I was able to be very clear about how I felt. I told him that he had not done enough to document the performance issue, and that if he wanted to institute discipline it would have to be at the lowest level. In the past, I would have been more deferential and said, …Let?s compromise and do it at step two or three.? But I didn?t do it; I spoke out strongly and held my ground.”大连交通大学2012届本科生毕业设计 (论文) 外文翻译This was the second study for Shane Smith, director of HR at Coca-Cola. “I didit for the first time in 2002. Now I?m seeing some traction in the things I?ve been working on. I?m pleased to see the consistency with my evaluations of my performance when compared to my raters.”What It All MeansUlrich believes that HR professionals who would have succeeded 30, 20, even 10 years ago, are not as likely to succeed today. They are expected to play new roles. To do so, they will need the new competencies.Ulrich urges HR to reflect on the new competencies and what they reveal about the future of the HR profession. His message is direct and unforgiving. “Legacy HR work is going, and HR people who don?t change with it will be gone.” Still, he remains optimistic that many in HR are heeding his call. “Twenty percent of HRpeople will never get it; 20 percent are really top performing. The middle 60 percent are moving in the right direction,” says Ulrich.“Within that 60 percent there are HR professionals who may be at the table but are not contributing fully,” he adds. “That?s the group I want to talk to. ... I want to show them what they need to do to have an impact.”As a start, Ulrich recommends HR professionals consider initiating three conversations. “One is with your business leaders. Review the competencies withthem and ask them if you?re doing them. Next, pose the same questions to your HR team. Then, ask yourself whether you really know the bu siness or if you?re glossing on the surface.” Finally, set your priorities. “Our data say: …Get working on thatCredible Activist!? ”Robert J. Grossman, a contributing editor of HR Magazine, is a lawyer and aprofessor of management studies at Marist College in Poughkeepsie, N.Y. from:HR Magazine, 2007,06 Robert J. Grossman ,大连交通大学2012届本科生毕业设计 (论文) 外文翻译译文:人力资源管理的新型胜任力如何在人力资源管理领域取得更大成功,需要怎样的专业知识和技能, 从1988年开始，密歇根大学的商业管理教授Dave Ulrich先生和他的助手们就开始研究这个课题。

软件工程专业毕业设计外文文献翻译1000字本文将就软件工程专业毕业设计的外文文献进行翻译，能够为相关考生提供一定的参考。

外文文献1: Software Engineering Practices in Industry: A Case StudyAbstractThis paper reports a case study of software engineering practices in industry. The study was conducted with a large US software development company that produces software for aerospace and medical applications. The study investigated the company’s software development process, practices, and techniques that lead to the production of quality software. The software engineering practices were identified through a survey questionnaire and a series of interviews with the company’s software development managers, software engineers, and testers. The research found that the company has a well-defined software development process, which is based on the Capability Maturity Model Integration (CMMI). The company follows a set of software engineering practices that ensure quality, reliability, and maintainability of the software products. The findings of this study provide a valuable insight into the software engineering practices used in industry and can be used to guide software engineering education and practice in academia.IntroductionSoftware engineering is the discipline of designing, developing, testing, and maintaining software products. There are a number of software engineering practices that are used in industry to ensure that software products are of high quality, reliable, and maintainable. These practices include software development processes, software configuration management, software testing, requirements engineering, and project management. Software engineeringpractices have evolved over the years as a result of the growth of the software industry and the increasing demands for high-quality software products. The software industry has developed a number of software development models, such as the Capability Maturity Model Integration (CMMI), which provides a framework for software development organizations to improve their software development processes and practices.This paper reports a case study of software engineering practices in industry. The study was conducted with a large US software development company that produces software for aerospace and medical applications. The objective of the study was to identify the software engineering practices used by the company and to investigate how these practices contribute to the production of quality software.Research MethodologyThe case study was conducted with a large US software development company that produces software for aerospace and medical applications. The study was conducted over a period of six months, during which a survey questionnaire was administered to the company’s software development managers, software engineers, and testers. In addition, a series of interviews were conducted with the company’s software development managers, software engineers, and testers to gain a deeper understanding of the software engineering practices used by the company. The survey questionnaire and the interview questions were designed to investigate the software engineering practices used by the company in relation to software development processes, software configuration management, software testing, requirements engineering, and project management.FindingsThe research found that the company has a well-defined software development process, which is based on the Capability Maturity Model Integration (CMMI). The company’s software development process consists of five levels of maturity, starting with an ad hoc process (Level 1) and progressing to a fully defined and optimized process (Level 5). The company has achieved Level 3 maturity in its software development process. The company follows a set of software engineering practices that ensure quality, reliability, and maintainability of the software products. The software engineering practices used by the company include:Software Configuration Management (SCM): The company uses SCM tools to manage software code, documentation, and other artifacts. The company follows a branching and merging strategy to manage changes to the software code.Software Testing: The company has adopted a formal testing approach that includes unit testing, integration testing, system testing, and acceptance testing. The testing process is automated where possible, and the company uses a range of testing tools.Requirements Engineering: The company has a well-defined requirements engineering process, which includes requirements capture, analysis, specification, and validation. The company uses a range of tools, including use case modeling, to capture and analyze requirements.Project Management: The company has a well-defined project management process that includes project planning, scheduling, monitoring, and control. The company uses a range of tools to support project management, including project management software, which is used to track project progress.ConclusionThis paper has reported a case study of software engineering practices in industry. The study was conducted with a large US software development company that produces software for aerospace and medical applications. The study investigated the company’s software development process,practices, and techniques that lead to the production of quality software. The research found that the company has a well-defined software development process, which is based on the Capability Maturity Model Integration (CMMI). The company uses a set of software engineering practices that ensure quality, reliability, and maintainability of the software products. The findings of this study provide a valuable insight into the software engineering practices used in industry and can be used to guide software engineering education and practice in academia.外文文献2: Agile Software Development: Principles, Patterns, and PracticesAbstractAgile software development is a set of values, principles, and practices for developing software. The Agile Manifesto represents the values and principles of the agile approach. The manifesto emphasizes the importance of individuals and interactions, working software, customer collaboration, and responding to change. Agile software development practices include iterative development, test-driven development, continuous integration, and frequent releases. This paper presents an overview of agile software development, including its principles, patterns, and practices. The paper also discusses the benefits and challenges of agile software development.IntroductionAgile software development is a set of values, principles, and practices for developing software. Agile software development is based on the Agile Manifesto, which represents the values and principles of the agile approach. The manifesto emphasizes the importance of individuals and interactions, working software, customer collaboration, and responding to change. Agile software development practices include iterative development, test-driven development, continuous integration, and frequent releases.Agile Software Development PrinciplesAgile software development is based on a set of principles. These principles are:Customer satisfaction through early and continuous delivery of useful software.Welcome changing requirements, even late in development. Agile processes harness change for the customer's competitive advantage.Deliver working software frequently, with a preference for the shorter timescale.Collaboration between the business stakeholders and developers throughout the project.Build projects around motivated individuals. Give them the environment and support they need, and trust them to get the job done.The most efficient and effective method of conveying information to and within a development team is face-to-face conversation.Working software is the primary measure of progress.Agile processes promote sustainable development. The sponsors, developers, and users should be able to maintain a constant pace indefinitely.Continuous attention to technical excellence and good design enhances agility.Simplicity – the art of maximizing the amount of work not done – is essential.The best architectures, requirements, and designs emerge from self-organizing teams.Agile Software Development PatternsAgile software development patterns are reusable solutions to common software development problems. The following are some typical agile software development patterns:The Single Responsibility Principle (SRP)The Open/Closed Principle (OCP)The Liskov Substitution Principle (LSP)The Dependency Inversion Principle (DIP)The Interface Segregation Principle (ISP)The Model-View-Controller (MVC) PatternThe Observer PatternThe Strategy PatternThe Factory Method PatternAgile Software Development PracticesAgile software development practices are a set ofactivities and techniques used in agile software development. The following are some typical agile software development practices:Iterative DevelopmentTest-Driven Development (TDD)Continuous IntegrationRefactoringPair ProgrammingAgile Software Development Benefits and ChallengesAgile software development has many benefits, including:Increased customer satisfactionIncreased qualityIncreased productivityIncreased flexibilityIncreased visibilityReduced riskAgile software development also has some challenges, including:Requires discipline and trainingRequires an experienced teamRequires good communicationRequires a supportive management cultureConclusionAgile software development is a set of values, principles, and practices for developing software. Agile software development is based on the Agile Manifesto, which represents the values and principles of the agile approach. Agile software development practices include iterative development, test-driven development, continuous integration, and frequent releases. Agile software development has many benefits, including increased customer satisfaction, increased quality, increased productivity, increased flexibility, increased visibility, and reduced risk. Agile software development also has some challenges, including the requirement for discipline and training, the requirement for an experienced team, the requirement for good communication, and the requirement for a supportive management culture.。

英文文献原文及译文学生姓名：赵凡学号：1021010639学院：软件学院专业：软件工程指导教师：武敏顾晨昕2014年 6月英文文献原文The use of skinWhat is a skin? In the role of setting, the preparations made for the animation in the final process is skinning. The so-called skinning skinning tool is to use role-model role do with our skeletal system to help set the course together. After this procedure, fine role model can be rendered on real numbers can be made into animation. Bones in skinning process, in which the position is called Bind Pose. After the skin, bone deformation of the skin caused by the Games. However, sometimes inappropriate distortion, which requires bone or skin to make the appropriate changes, then you can make use of relevant command to restore the bone binding position, and then disconnect the association between bone and skin. In Maya, you can always put the bones and skin disconnected or reconnected. There is a direct way to skin the skin (skin flexible rigid skinning) and indirect skin (or wrap the lattice deformation of flexible or rigid skinning skinning joint use).In recent years, more and more 3D animation software, a great competition in the market, software companies are constantly developing and updating the relevant software only more humane, but in three-dimensional animation maya mainstream animation software. Able to create bone, meat, God's role is that each CG digital artists dream. Whether the digital characters charm, the test is the animator of life, understanding of life. Digital character to have bone and meat producers are required for the role of the body and has a full grasp of motor function. In addition, the roles of whether there is realism, the key lies in the design and production of the skin, which is skinning animation software for skilled technical and creative mastery is essential. Skin is ready to work in animation final steps, after this procedure, you can do the movements designed, if the skin did not do the work, after the animation trouble, so the skin is very important.As the three-dimensional animation with accuracy and authenticity, the current three-dimensional animation is rapidly developing country, nowadays the use ofthree-dimensional animation everywhere, the field of architecture, planning areas, landscape areas, product demonstrations, simulated animation, film animation, advertising, animation, character animation, virtual reality and other aspects of three-dimensional animation fully reflects the current importance. If compared to the three-dimensional animation puppet animation in real life, then the doll puppet animation equivalent of Maya modeling, puppet performers equivalent Maya animators and puppet steel joints in the body is the skeletal system. Bones in the animation will not be the final rendering, its role is only equivalent to a bracket that can simulate real bones set of major joints to move, rotate, etc.. When the bones are set, we will be bound to the skeleton model, this step is like a robot mounted to a variety of external parts, like hanging, and then through the various settings, add a keyframe animation on bone, and then drive to be bound by the bones corresponding to the model on the joints. Thus, in the final animation, you can see the stiffness of a stationary model with vitality. The whole process from the rigging point of view, may not compare more tedious keyframe animation, rigging, but it is the core of the whole three-dimensional animation, and soul.Rigging plays a vital role in a three-dimensional animation. Good rigging easy animation production, faster and more convenient allows designers to adjust the action figures. Each step are bound to affect the skeleton final animation, binding is based on the premise of doing animation, animators animate convenient, good binding can make animation more fluid, allowing the characters to life even more performance sex. In addition to rigging as well as expression of the binding character, but also to let people be able to speak or behave different facial expressions. Everything is done in order to bind the animation is set, it is bound to set a good animation is mainly based on the entire set of styles and processes. Rigging is an indispensable part in the three-dimensional animation.Three-dimensional animation production process: model, texture, binding, animation, rendering, special effects, synthesis. Each link is associated. Model and material determines the style of animation, binding, and animation determine fluency animation, rendering, animation effects, and synthetic colors and determine the finalresult.Three-dimensional animation, also known as 3D animation, is an emerging technology. Three-dimensional animation gives a three-dimensional realism, even subtle animal hair, this effect has been widely applied to the production of film and television in many areas, education, and medicine. Movie Crash, deformed or fantasy scenes are all three-dimensional animation in real life. Designers in the first three-dimensional animation software to create a virtual scene, and then create the model according to the proportion, according to the requirements set trajectory models, sports, and other parameters of the virtual camera animation, and finally as a model assigned a specific material, and marked the lights , the final output rendering, generating the final screen. DreamWorks' "Shrek" and Pixar's "Finding Nemo" is so accomplished visual impact than the two-dimensional animation has.Animated film "Finding Nemo" extensive use of maya scene technology. Produced 77,000 jellyfish animation regardless of the technical staff or artist is one of the most formidable challenge. This pink translucent jellyfish is most needed is patience and skill, you can say, jellyfish appeared animated sea creatures taken a big step. His skin technology can be very good. The use of film roles skinning techniques is very good, so that each character is vivid, is not related to expression, or action is so smooth, these underwater underwater world is so beautiful. Maya maya technology for the creation of the first to have a full understanding and knowledge. He first thought of creative freedom virtual capacity, but the use of technology has limitations. When the flexible skinning animation technique many roles in the smooth bound for editing, re-allocation tools needed to adjust the skeletal model for the control of the weight through the right point, every detail clownfish are very realistic soft. In the joint on the affected area should smear, let joints from other effects, this movement was not wearing a tie. Used less rigid, rigid lattice bound objects must be created in a position to help the bones of the joint motion. Animated film "Finding Nemo," the whole movie a lot of facial animation, facial skin but also a good technique to make facial expressions, the facial animation is also animated, and now more and more animated facial animationtechnology increasingly possible, these should be good early skin behind it will not affect the expression, there is therefore the creation of the film how maya digital technology, play his video works styling advantages and industrial processes are needed to explore creative personnel, all and three-dimensional figures on the production of content, from maya part. Two-dimensional hand-painted parts, post-synthesis of several parts, from a technical production, artistic pursuit. Several angles to capture the entire production cycle of creation. Maya techniques used in the animated film "Finding Nemo", the flexible skinning performance of many, clown face on with a lot of smooth binding, so more people-oriented, maya application of technical advantages in certain limited extent. Realistic three-dimensional imaging technology in the animation depth spatial density, the sense of space, mysterious underwater world to play the most. Because lifelike action, it also brings the inevitable footage and outdoor sports realistic density, but also to explore this movie maya main goal of the three-dimensional animation.英文文献译文蒙皮的运用什么是蒙皮？在角色设定中，为动画所作的准备工作里的最后一道工序就是蒙皮。

毕业设计说明书英文文献及中文翻译班姓学专级：名：院：业：10210A02 1021010633梁卓越软件学院软件工程（软件开发与测试）指导教师：韩涛常旭青2014 年 6月学号：英文文献出自《IBM System Journal,2006,44(2):33-37》作者：Malcolm DavisS truts——An Open-source MVC Implementation This article introduces Struts, a Model-View-Controller implementation that uses servlets and JavaServer Pages (JSP) technology.Struts can help you control change in your Web project and promote specialization. Even if you never implement a system with Struts, you may get some ideas for your future servlets and JSP page implementationIntroductionKids in grade school put HTML pages on the Internet. However,there is a monumental difference between a grade school page and a professionally developed Web site. The page designer(or HTML developer)must understand colors, the customer,product flow, page layout, browser compatibility, image creation, JavaScript, and more. Putting a great looking site together takes a lot of work, and most Java developers are more interested in creating a great looking object interface than a user interface. JavaServer Pages (JSP) technology provides the glue between the page designer and the Java developer.If you have worked on a large-scale Web application, you understand the term change.Model-View-Controller(MVC) is a design pattern put together to help control change.MVC decouples interface from business logic and data. Struts is an MVC implementation that uses Servlets 2.2 and JSP 1.1 tags, from the J2EE specifications, as part of the implementation.You may never implement a system with Struts, but looking at Struts may give you some ideas on your future Servlets and JSP implementations.Model-View-Controller(MVC)JSP tags solved only part of our problem.We still have issues with validation, flow control, and updating the state of the application. This is where MVC comes to the rescue. MVC helps resolve some of the issues with the single module approach by dividing the problem into three categories:ModelThe model contains the core of the application's functionality.The modelencapsulates the state of the application. Sometimes the only functionality itcontains is state. It knows nothing about the view or controller.ViewThe view provides the presentation of the model. It is the look of theapplication.The view can access the model getters,but it has no knowledge ofthe setters.In addition,it knows nothing about the controller.The view shouldbe notified when changes to the model occur.ControllerThe controller reacts to the user input. It creates and sets the model.MVC Model 2The Web brought some unique challenges to software developers,mostnotably the stateless connection between the client and the server.Thisstateless behavior made it difficult for the model to notify the view of changes.On the Web, the browser has to re-query the server to discover modification to the state of the application.Another noticeable change is that the view uses different technology forimplementation than the model or controller.Of course,we could use Java(or PERL,C/C++or what ever) code to generate HTML. There are severaldisadvantages to that approach:Java programmers should develop services,not HTML.Changes to layout would require changes to code.Customers of the service should be able to create pages to meet their specificneeds.The page designer isn't able to have direct involvement in page development.HTML embedded into code is ugly.For the Web, the classical form of MVC needed to change. Figure4displaysthe Web adaptation of MVC,also commonly known as MVC Model 2 orMVC2.Struts detailsDisplayed in Figure 6 is a stripped-down UML diagram of theorg.apache.struts.action package.Figure6 shows the minimal relationshipsamong ActionServlet(Controller),ActionForm (Form State),and Action(Model Wrapper).The ActionServlet classDo you remember the days of function mappings? You would map some input event to a pointer to a function.If you where slick, you would place the configuration information into a file and load the file at run time.Function pointer arrays were the good old days of structured programming in C.Life is better now that we have Java technology,XML,J2EE,and all that.The Struts Controller is a servlet that maps events(an event generally being anHTTP post)to classes.And guess what -- the Controller uses a configurationfile so you don_t have to hard-code the values.Life changes, but stays thesame.ActionServlet is the Command part of the MVC implementation and is thecore of the Framework.ActionServlet (Command) creates and uses Action,an ActionForm, and ActionForward. As mentioned earlier, the struts-config.xmlfile configures the Command.During the creation of the Web project, Actionand ActionForm are extended to solve the specific problem space. The filestruts-config.xml instructs ActionServlet on how to use the extended classes.There are several advantages to this approach:The entire logical flow of the application is in a hierarchical text file. Thismakes it easier to view and understand, especially with large applications.The page designer does not have to wade through Java code to understand the flow of the application.The Java developer does not need to recompile code when making flowchanges.Command functionality can be added by extending ActionServlet.The ActionForm classActionForm maintains the session state for the Web application.ActionForm is an abstract class that is sub-classed for each input form model. When I sayinput form model, I am saying ActionForm represents a general concept ofdata that is set or updated by a HTML form.For instance,you may have aUserActionForm that is set by an HTML Form.The Struts framework will:Check to see if a UserActionForm exists;if not, it will create an instance ofthe class.Struts will set the state of the UserActionForm using corresponding fieldsfrom the HttpServletRequest.No more dreadful request.getParameter()calls.For instance,the Struts framework will take fname from request stream andcall UserActionForm.setFname().The Struts framework updates the state of the UserActionForm before passing it to the business wrapper UserAction.Before passing it to the Action class,Struts will also conduct form statevalidation by calling the validation()method on UserActionForm.Note: This is not always wise to do. There might be ways of using UserActionForm inother pages or business objects, where the validation might be different.Validation of the state might be better in the UserAction class.The UserActionForm can be maintained at a session level.Notes:The struts-config.xml file controls which HTML form request maps to whichActionForm.Multiple requests can be mapped UserActionForm.UserActionForm can be mapped over multiple pages for things such aswizards.The Action classThe Action class is a wrapper around the business logic.The purpose of Action class is to translate the HttpServletRequest to the business logic. To use Action, subclass and overwrite the process()method.The ActionServlet(Command)passes the parameterized classes to ActionForm using the perform()method.Again, no more dreadful request.getParameter()calls.By thetime the event gets here,the input form data (or HTML form data)has already been translated out of the request stream and into an ActionForm class.Struts,an MVC2 implementationStruts is a set of cooperating classes, servlets,and JSP tags that make up a reusable MVC2design.This definition implies that Struts is a framework, rather than a library, but Struts also contains an extensive tag library and utility classes that work independently of the framework. Figure5 displays an overview of Struts.Struts overviewClient browserAn HTTP request from the client browser creates an event.The Web container will respond with an HTTP response.ControllerThe Controller receives the request from the browser,and makes the decisionwhere to send the request.With Struts,the Controller is a command designpattern implemented as a servlet.The struts-config.xml file configures theController.Business logicThe business logic updates the state of the model and helps control the flow of the application.With Struts this is done with an Action class as a thin wrapper to the actual business logic.Model stateThe model represents the state of the application.The business objects updatethe application state. ActionForm bean represents the Model state at a sessionor request level,and not at a persistent level. The JSP file reads informationfrom the ActionForm bean using JSP tags.ViewThe view is simply a JSP file. There is no flow logic,no business logic, and no model information-- just tags. Tags are one of the things that make Strutsunique compared to other frameworks like Velocity.Note:"Think thin"when extending the Action class. The Action class should control the flow and not the logic of the application.By placing the business logic in a separate package or EJB,we allow flexibility and reuse.Another way of thinking about Action class is as the Adapter design pattern. The purpose of the Action is to "Convert the interface of a class into another interface the clients expect.Adapter lets classes work together that couldn_t otherwise because of incompatibility interface"(from Design Patterns - Elements of Reusable OO Software by Gof).The client in this instance is the ActionServlet that knows nothing about our specific business class interface. Therefore, Struts provides a business interface it does understand,Action. By extending the Action, we make our business interface compatible with Struts business interface. (An interesting observation is that Action isa class and not an interface.Action started as an interface and changed into a class over time.Nothing's perfect.)The Error classesThe UML diagram (Figure6)also included ActionError and ActionErrors. ActionError encapsulates an individual error message.ActionErrors is a container of ActionError classes that the View can access using tags.ActionErrors is Struts way of keeping up with a list of errors.The ActionMapping classAn incoming event is normally in the form of an HTTP request, which the servlet Container turns into an HttpServletRequest.The Controller looks at the incoming event and dispatches the request to an Action class. The struts-config.xml determines what Action class the Controller calls. The struts-config.xml configuration information is translated into a set of ActionMapping, which are put into container of ActionMappings. (If you have not noticed it,classes that end with s are containers) The ActionMapping contains the knowledge of how a specific event maps to specific Actions.The ActionServlet(Command) passes the ActionMapping to the Action class via the perform()method. This allows Action to access the information to control flow. ActionMappingsActionMappings is a collection of ActionMapping objects.Struts prosUse of JSP tag mechanismThe tag feature promotes reusable code and abstracts Java code from the JSPfile.This feature allows nice integration into JSP-based development tools that allow authoring with tags.Tag libraryWhy re-invent the wheel,or a tag library?If you cannot find something youneed in the library, contribute.In addition,Struts provides a starting point ifyou are learning JSP tag technology.Open sourceYou have all the advantages of open source,such as being able to see the codeand having everyone else using the library reviewing the code. Many eyesmake for great code review.Sample MVC implementationStruts offers some insight if you want to create your own MVCimplementation.Manage the problem spaceDivide and conquer is a nice way of solving the problem and making theproblem manageable. Of course,the sword cuts both ways. The problem ismore complex and needs more management.Struts consYouthStruts development is still in preliminary form. They are working towardreleasing a version 1.0,but as with any 1.0version,it does not provide all thebells and whistles.ChangeThe framework is undergoing a rapid amount of change.A great deal ofchange has occurred between Struts0.5 and1.0. You may want to downloadthe most current Struts nightly distributions,to avoid deprecated methods.Inthe last 6 months,I have seen the Struts library grow from90K to over270K.I had to modify my examples several times because of changes in Struts,and Iam not going to guarantee my examples will work with the version of Strutsyou download.C orrect level of abstractionDoes Struts provide the correct level of abstraction? What is the proper level of abstraction for the page designer?That is the $64K question.Should we allowa page designer access to Java code in page development? Some frameworkslike Velocity say no, and provide yet another language to learn for Webdevelopment. There is some validity to limiting Java code access in UIdevelopment.Most importantly,give a page designer a little bit of Java,andhe will use a lot of Java.I saw this happen all the time in Microsoft ASPdevelopment.In ASP development,you were supposed to create COM objectsand then write a little ASP script to glue it all together. Instead,the ASPdevelopers would go crazy with ASP script.I would hear"Why wait for aCOM developer to create it when I can program it directly with VBScript?"Struts helps limit the amount of Java code required in a JSP file via taglibraries.One such library is the Logic Tag,which manages conditionalgeneration of output,but this does not prevent the UI developer from goingnuts with Java code.Whatever type of framework you decide to use, youshould understand the environment in which you are deploying andmaintaining the framework.Of course,this task is easier said than done.Limited scopeStruts is a Web-based MVC solution that is meant be implemented withHTML, JSP files, and servlets.J2EE application supportStruts requires a servlet container that supports JSP1.1 and Servlet 2.2specifications.This alone will not solve all your install issues,unless you areusing Tomcat3.2.I have had a great deal of problems installing the librarywith Netscape iPlanet 6.0, which is supposedly the first J2EE-compliantapplication server. I recommend visiting the Struts User Mailing List archive(see Resources) when you run into problems.ComplexitySeparating the problem into parts introduces complexity.There is no questionthat some education will have to go on to understand Struts. With the constantchanges occurring, this can be frustrating at times.Welcome to the Web.Where is...I could point out other issues,for instance, where are the client side validations,adaptable workflow, and dynamic strategy pattern for the controller? However,at this point, it is too easy to be a critic, and some of the issues are insignificant, or are reasonable for a1.0release.The way the Struts team goes at it, Strutsmight have these features by the time you read this article, or soon after. Future of StrutsThings change rapidly in this new age of software development.In less than 5 years, I have seen things go from cgi/perl, to ISAPI/NSAPI, to ASP with VB, and now Java and J2EE. Sun is working hard to adapt changes to the JSP/servlet architecture, just as they have in the past with the Java language and API. You can obtain drafts of the new JSP 1.2 and Servlet 2.3 specifications from the Sun Web site. Additionally,a standard tag library for JSP files is appearing.中文翻译Struts——一种开源MVC的实现这篇文章介绍 Struts，一个使用servlet 和JavaServer Pages 技术的一种 Model-View-Controller 的实现。

while Ifyou a ]. Every软件专业毕业论文外文文献中英文翻译Object landscapes and lifetimesTechnically, OOP is just about abstract data typing, inheritance, and polymorphism, but otheissues can be at least as important. The remainder of this section will cover these issues.One of the most important factors is the way objects are created and destroyed. Where is thedata for an object and how is the lifetime of the object controlled? There are different philosoat work here. C++ takes the approach that control of efficiency is the most important issue, sogivesthe programmer a choice.For maximum run-timespeed,the s torageand lifetimecan bedeterminedwhile the program isbeing written,by placingthe objectson the stack(thesearesometimes called automatic or scoped variables) or in the static storage area. This places a prion the speed of storage allocation and release, and control of these can be very valuable in somsituations. However, you sacrifice flexibility because you must know the exact quantity, lifetimand type of objectsyou're writing the program. are trying to solvemore generalproblem such as computer-aided design, warehouse management, or air-traffic control, this is toorestrictive.The second approach is to create objects dynamically in a pool of memory called the heap. Inthis approach, you don't know until run-time how many objects you need, what their lifetime is,what theirexacttypeis.Those aredeterminedatthespurof themoment whiletheprogram isrunning. If you need a new object, you simply make it on the heap at the point that you need it.Because the storage is managed dynamically, at run-time, the amount of time required to allocatestorage on the heap is significantly longer than the time to create storage on the stack. (Creatstorage on the stack is often a single assembly instruction to move the stack pointer down, andanother to move it back up.) The dynamic approach makes the generally logical assumption thatobjects tend to be complicated, so the extra overhead of finding storage and releasing that storwill not have an important impact on the creation of an object. In addition, the greater flexibiessential to solve the general programming problem.Java uses the second approach, exclusively timeyou want to create an object, you useIn you when th but any new youin C (suchthe new keyword to build a dynamic instance of that object.There's another issue, however, and that's the lifetime of an object. With languages that alobjectsto be createdon the stack,the compilerdetermineshow long the objectlastsand canautomatically destroy it. However, if you create it on the heap the compiler has no knowledge ofits lifetime.alanguage like C++,must determine programmatically to destroy theobject, which can lead to memory leaks if you don’t do it correctly (and this is a common problin C++ programs). Java provides a feature called a garbage collector that automatically discoverwhen an object is no longer in use and destroys it. A garbage collector is much more convenientbecause it reduces the number of issues that you must track and the code you must write. Moreimportant, the garbage collector provides a much higher level of insurance against the insidiousproblem of memory leaks (which has brought many a C++ project to its knees).The rest of this section looks at additional factors concerning object lifetimes and landsca1. The singly rooted hierarchyOne of the issues in OOP that has become especially prominent since the introduction of C++iswhether a llclassesshouldultimatelybe inheritedfrom a singlebase class.In Java (aswithvirtually all other OOP languages)answer is “yes” and the name of this ultimate base class issimply Object. It turns out that the benefits of the singly rooted hierarchy are many.All objectsin a singlyrootedhierarchyhave an interfacein common, so they are allultimatelythe same type.The alternative(providedby C++) is thatyou don’tknow thateverything is the same fundamental type. From a backward-compatibility standpoint this fits themodel of C betterand can be thoughtof as lessrestrictive, when you want to do full-onobject-orientedprogramming you must then buildyour own hierarchyto providethe sameconvenience that’s built into other OOP languages. And in library classacquire, someother incompatible interface will be used. It requires effort (and possibly multiple inheritancework the new interface into your design. Is the extra “flexibility” of C++ worth it? If you neit —if you have a large investment —it’s quite valuable. If you’re starting from scratch, otheralternatives such as Java can often be more productive.All objects in a singly rooted hierarchyas Java provides) can be guaranteed to havecertain functionality. You know you can perform certain basic operations on every object in yoursystem. A singly rooted hierarchy, along with creating all objects on the heap, greatly simplifitoso ’s that is a it’sargument passing (one of the more complex topics in C++).A singly rooted hierarchy makes it much easier to implement a garbage collector (which isconvenientlybuiltintoJava).The necessarysupportcan be installed the b ase class,and thegarbage collector can thus send the appropriate messages to every object in the system. Withoutsinglyrootedhierarchyand a system to manipulatean objectvia a reference,itisdifficultimplement a garbage collector.Since run-time type information is guaranteed to be in all objects, you’ll never end up withobject whose type you cannot determine. This is especially important with system level operationsuch as exception handling, and to allow greater flexibility in programming.2 .Collection libraries and support for easy collection useBecause a container is a tool that you’ll use frequently, it makes sense to have a librarycontainersthatare builtin a reusablefashion,so you can take one off the shelfBecause acontainer is a tool that you’ll use frequently, it makes sense to have a library of containersbuilt in a reusable fashion, so you can take one off the shelf and plug it into your program. Japrovides such a library, which should satisfy most needs.Downcasting vs. templates/genericsTo make thesecontainersreusable,they hold the one universaltype in Java thatwaspreviously mentioned: Object. The singly rooted hierarchy means that everything is an Object, soa container that holds Objects can hold anything. This makes containers easy to reuse.To use such a container, you simply add object references to it, and later ask for them backBut, since the container holds only Objects, when you add your object reference into the containit is upcast to Object, thus losing its identity. When you fetch it back, you get an Object refeand not a reference to the type that you put in. So how do you turn it back into something thatthe useful interface of the object that you put into the container?Here, the cast is used again, but this time you’re not casting up the inheritance hierarchymore general type, you cast down the hierarchy to a more specific type. This manner of casting icalled downcasting. With upcasting, you know, for example, that a Circle is aittype of Shapesafe to upcast, but you don’t knowObject an necessarily a Circle or so Shape hardly’t itit to get by safe to downcast unless you know that’s what you’re dealing with.It’s not completely dangerous, however, because if you downcast to the wrong thing you’llget a run-time error called an exception, which will be described shortly. When you fetch objectreferences from a container, though, you must have some way to remember exactly what they areso you can perform a proper downcast.Downcasting and the run-time checks require extra time for the running program, and extraeffort from the programmer. Wouldnmake sense tosomehow create the container so that itknows the types that it holds, eliminating the need for the downcast and a possible mistake? Thesolution is parameterized types, which are classes that the compiler can automatically customizework with particulartypes.For example,with a parameterizedcontainer,the compilercouldcustomize that container so that it would accept only Shapes and fetch only Shapes.Parameterized types are an important part of C++, partly because C++ has no singly rootedhierarchy. In C++, the keyword that implements parameterized types is “template.” Java current has no parameterized types since it is possible for —however awkwardly —using thesingly rooted hierarchy. However, a current proposal for parameterized types uses a syntax thatstrikingly similar to C++ templates.。

咋一篇文章连个题目也没有啊？？？This text analysis the mechanism of Hibernate and Struts, put forward 1 kind EE according to the J2 of the Hibernate and the Struts application development strategy.In this kind of strategy, the model layer use a Hibernate realization and see diagram and controller to then use a Struts frame a realization.So can consumedly lower the development efficiency that the Ou of code match sex and exaltation system. The key word Hibernate, Struts, the MVC, hold out for long time a layer one preface along with the Java technique of gradual mature and perfect, Be establishment business enterprise class application of standard terrace, the J2 EE terrace got substantial of development.Several technique asked for help from to include in the J2 EE norm:Enterprise JavaBean(EJB), Java Servlets(Servlet), Java Server Pages(JSP), Java Message Service(JMS)...etc., development many application system.But, also appeared some problem in the tradition J2 the EE the application of the development the process:1)the antinomy of of data model and logic model.Currently the database of usage basically and all is relation type database, but the Java be essentially a kind of the language which face to object, object at saving with read usage SQL and JDBC carry on a database operation and lowered plait distance of efficiency and system of can maintenance;2)tradition of J2 EE application much the adoption is according to the EJB heavy weight frame, this kind of frame suitable for develop a large business enterprise application, but usage the EJB container carry on development and adjust to try to need to be waste a great deal of time.For lowering the Ou of code to match sex, exaltation system of development efficiency, this text put forward 1 kind EE according to the J2 of the Struts frame and the Hibernate frame application development strategy. 2 datas' holding out for long time layer and Hibernate is one piece according to hold out for long time layer frame, is a kind of realization object and relationof the tool which reflect to shoot(O/R Mapping), it carried on the object of the lightweight to pack to the JDBC and make procedure member can usage object plait distance thought to operation database.It not only provided to shoot from Java to reflect of data form, but also provided a data a search and instauration mechanism.Opposite in usage JDBC and SQL to operation database, use a Hibernate ability consumedly of exaltation realization of efficiency.The Hibernate frame use allocation document of the form come to the reflect of the definition Java object and data form to shoot relation, in the meantime at more deep of level of data form of relation explanation for the relations such as inherit of and containment etc. of Java object.Pass the usage HQL language sentence complications of relation the calculate way use the way of object description, to a large extent simplification logarithms according to of search, speed development of efficiency.Have in the Hibernate a simple but keep the API of view, used for to the database mean of object performance search.Want to establish or the modification be these objects, need in the procedure carry on with them to hand over with each other, then tell Hibernate to keep.So, a great deal of pack hold out for long time turn operation of business logic no longer demand write a trivial JDBC language sentence, make data last long thus the layer got biggest of simplification.3 use the Struts realization MVC structure MVC(Model-View-Controller) is put forward by the Trygve Reenskaug, first drive application in the environment SmallTalk-80, is many to hand over with each other with interface system of constitute foundation.According to the need of variable of the interface design, MVC hand over with each other constitute of system to resolve into model and see diagram, controller three part. Model(Model) is software processing problem logic at independence in outside manifestation undercontents and form circumstance of inside abstract, packed the core data, logic of problem and function of calculation relation, independence in concrete of interface expression and I/O operation.See diagram(View) mean information and particular form demonstration of model data and logic relation and appearance to the customer.It acquire a manifestation information from the model, there can be many for homology of information dissimilarity of manifestation form or see diagram.Thecontroller(Controller) is a processing the customer hand over with software with each other operation of, its job is control provide model in any variety of dissemination, insure a customer interface among the model of rightness should contact;It accept a customer of importation, give° the importation feedback model, then realization compute model control, is make model and see diagram to moderate work of ually 1 see a diagram rightness should a controller.Model, see separate of diagram and controller, make a model be able to have many manifestation to see diagram.If the customer pass a certain see the controller of diagram change the data of model, all other dependence in these see of data diagram all should reflection arrive these variety.When therefore and regardless occurrence what data variety, controller all would variety notice allly see diagram, cause manifestation of renewal.This is actually a kind of variety of model-dissemination mechanism.The Struts frame is to be the item of Apache Jakarta to constitute part to publish luck to do at the earliest stage, it inheritted MVC of each item characteristic, and did according to the characteristics of J2 EE correspond of variety with expand.The Struts frame was good to combine Jsp, Java Servlet, Java Bean, Taglib etc. technique.In the Struts, what to undertake the controller role in the MVC be an ActionServlet.The ActionServlet is an in general use control module.This control module provided a processing all HTTPclaim which send out Struts of entrance point.Its interception with distribute these claim to arrive correspond of action type.(these action all of type is Action son type)Moreover the control module is also responsible for using to correspond of claim the parameter fill Action Form(FromBean), and pass action type(ActionBean).Action type the business logic of the interview core, then interview Java Bean or adjust to use EJB.End action type control the power pass follow-up of JSP document, from JSP document born see diagram.All these control logic make use of Struts-config.xml the document come to allocation.See diagram in the Struts frame main from JSP born page completion, the Struts provide abundant of JSP label database, this is advantageous to separating performance logic and procedure logic.The model is with 1 or the form existence of several Java Bean.In the Struts, main existence three kinds of Bean, respectively BE:Action, ActionForm, EJB perhaps Java Bean. The Struts frame have no concrete definition model layer of realization, in actually the development, model layer usually is close with business logic connect with each other, and want to carry on operation to the first floor data.The underneath's introduction is a kind of development strategy, lead the Hibernate into the model layer of Struts frame, usage it to carry on a data to pack with reflect to shoot, provide hold out for long time turn of support. 4 usage Hibernate and the Struts development J2 EE application 4.1 system structure diagram 3 manifestation according to Hibernate and Struts development strategy of system structure diagram.4.2 Development practice underneath combine a development practice, with in the J2 the EE the application very widespread customer register process for example, elucidation above-mentioned system structure is how concrete usage.The process of register is very clear:Customer from register page login.jsp importation register information, system to register theinformation carry on verification, if exactitude success register, otherwise hint correspond mistake information. In the development process, the usage Eclipse be used as development environment and added to carry to provide to the Struts and the Hibernate in the meantime better control and support of three square plug-in MyEclipse, Web server usage Tomcat, the database chose to use Mysql. Carry on an allocation to the Hibernate first, need to the system auto the born hibernate.cfg.xml carry on modification, allocation good database conjunction of various parameter and definition the data reflect to shoot a document.Because the Hibernate take of conjunction pond main used for test, the function isn't very good, can pass JNDI will it modification is usage Tomcat of conjunction pond.本文分析了Hibernate和Struts的机制，提出了一种基于Hibernate和Struts的J2EE 应用开发策略。

软件工程专业软件质量中英文资料外文翻译文献Planning for Software QualityIn this Chapter: Defining quality in software projects, working with your organization’s quality policy, Creating a quality management plan, Identifying how changes in time and cost will affect project quality.When it comes to quality, you’ve probably heard some great clichés: quality is planned into a project, not added through inspection(you should spend your time in planning quality instead of inspecting after you have errors).It’s always cheaper(and more efficient) to do a job right the first time around. Why is there always time to do work right the second time? Always underpromise and overdeliver.There sure are some catchy slogans, and clichés become clichés because they’re usually accurate. In this chapter we explore what quality is , how to plan it into your project, and how to create a quality management plan.6.1 Defining QualityBefore you can plan for quality, you must first define what quality is. Ask your customers, your project team, your management team, and even yourself what quality is and you get a variety of answers:What customers say: The software you create lives up to expectations, is reliable, and does some incredible things the customer doesn’t expect(or even think of ).What your project team says: The work is completed as planned and as expected, with few errors- and fewer surprises.What managers say: The customer is happy and the project delivers on time and on budget.What you may say: The project team completes its work according to its estimates, the customer is happy, and management is happy with the final costs andschedule.Quality, for everyone concerned, is the ability of the project and the project’s deliverable to satisfy the stated and implied requirement. Quality is all of items we mention here, but it’s more than just the deliverable; it’s following a process, meeting specified requirements, and performing to create the best possible deliverable. Everything, from the project kickoff meeting to the final testing, affects the project quality.6.2 Referring to the product scopeAs the project manager, you primary concern is satisfying the product scope. The product scope is the description of the software the customer expects from your project.If you work primarily to satisfy the product scope, then you’ll be in good shape with satisfying the customer’s expectations for quality. But, in order to satisfy the product scope you must first have several documents:Product scope description document. This document defines what the customer expects from the project. What are the characteristics of the software? This description becomes more complete as you progress through the project and gather more knowledge.Project requirements document. This document defines exactly what the project must create without being deemed a failure. What types of functionality should stakeholders be able to perform with the software? This document prioritizes the stakeholders’ requirements.Detailed design document. This document specifies how the project team will create units that meet the project requirements, which in turn will satisfy the product scope.Metrics for acceptability. Many software projects need metrics for acceptability. These metrics include speeds, data accuracy, and metrics from user acceptability tests. You’ll need to avoid vague metrics, such as good and fast. Instead, aim to define accurate numbers and determine how the values will be captured.Satisfying the product scope will assure that the customer is happy with you and with deliverables the project team has created. You will only satisfy the product scope if you plan how to do it. Quality is no accident.6.3 Referring to the project scopeThe project scope defines all of the work(and only the required work ) to createthe project deliverable. The project scope defines what will and won’t be included in the project deliverable. Project scope is different than the product scope, because the product scope describes only the finished deliverable, whereas the project scope describes the work and activities needed to reach the deliverable.You must define the project scope so that you use it as an appropriate quality tool. The project scope draws a line in the sand when it comes to project changes. Changes, as we’re sure you’ve experienced, can trickle into the project and cause problems with quality. Even the most innocent changes can bloom into monsters that wreck your project.Figure 6-1 shows the project manager’s approach to project changes and quality. Early in the project, during the initiation and planning stages, you safely entertain changes to the project. After you create the project scope, however, your rule when it comes to changes should be “Just say no!”Changes to the project may affect the quality of the product. This isn’t to say that changes should come into a project at all- far from it. But changes to the project must be examined, weighed, and considered for the affect on time, cost, and impact on project quality.6.3.1 Going the extra mileOne cliché that rings true is that it’s always better to underpromise and overdiliver. We’ve heard project managers tell us this is their approach to keep people happy. It sounds good, right? A customer asks for a piece of software that can communicate with a database through a Web form. Your project team, however, creates a piece of software that can communicate through a Web form to the customer’s database, and you add lots of query combinations for each table in the database. Fantastic!A valid argument can be made that you should never underpromise, but promise what you can deliver and live up to those promises. Technically, in project management, quality is achieved by meeting the customer’s expectations-not more than they expect, and certainly not less than they expect.Surprising the customer with more than the project scope outlines can actually backfire, for the following reasons: The customer may believe the project deliverable could have been completed faster without all the extras you’ve included. The customer may believe the project deliverable could have been completed for fewer dollars without all the extras you’ve included. If the customer discovers bugs in the software, the blame may lie with the extras. The customer may not want the extras,regardless of how ingenious you believe they are. Overdelivering is not meeting expectations: you’re not giving the customer what he or she asked for.Now, Having put the wet blanket on the fire of creativity, let us say this: communicate. We can’t emphasize enough how important it is to tell the customer what you can do, even if it’s more than what the customer has originally asked for. In software development, customers may need guidance on what each deliverable can do, and they look to you as the expert to help them make those decisions. But notice this process is done before the project execution begins, not during the implementation phase.The product scope and the project scope support one another. If the customer changes details in the product scope will also change. If not, then your project team will be completing a project scope that wo n’t create what the customer expects.Avoiding gold- plated softwareYou create gold-plated software when you complete a project, and the software is ready to go the customer, but suddenly realize that you have money to burn. If you find yourself with a hefty sum of cash remaining in the project budget, you may feel tempted to fix the situation with a lot of bling. After all, if you give the project deliverable to the customer exactly as planned, several things may happen: You customer may be initially happy that you’ve delivered underbudget. Then they’ll wonder whether you cut corners or just didn’t have a clue as to the actual cost of the project. The customer may wonder why your estimate and the actual cost of the project deliverable are not in sync. The remaining budget will be returned to the customer unless your contract stipulates otherwise. Other project managers may not be happy that you’ve created a massive, unused project budget when their projects have been strapped for cash. Key stakeholders may lose confidence in your future estimates and believe them to be bloated, padded, or fudged.This is , in case you haven’t guessed, a bad thing. The best thing to do is to deliver an accurate estimate to begin with and avoid this scenario altogether. We discuss time estimates in Chapter 8 and cost estimates in Chapter 9. For now, know that your customer’s confidence in future estimates is always measured on your ability to provide accurate estimates at the beginning of the process.If you find yourself in the scenario where you have a considerable amount of cash left in the project budget, the best thing to do is to give an accurate assessment to the customer of what you’ve accomplished in the project and what’s leftin the kitty. Don’t eat up the budget with extras, and don’t beat yourself up over it. Mistakes happen, especially to beginners, and it’s still more forgivable to be underbudget than it is to be overbudget.So should you also present extras to the customer when you present the project’s status and the remaining budget? If the extras are value-added scope changes, we say yes. If the extras are truly gold-plated extras to earn more dollars, then we say no. Software quality is based on whether the product delivers on its promises. If the proposed changes don’t make the software better, no one needs them.What you do on your current project may influence what you get to do on future projects. Honesty now pays dividends later.6.4 Examining quality versus gradeQuality and grade are not the same thing. Low quality is always a problem, but low grade may not be. Quality, as you know, is the ability of software to deliver on its promises. Grade is the ranking or classification we assign to things.Consider your next flight. You expect the airplane to safely launch, fly, and land. And you expect to be reasonably comfortable during the flight. You expect the behavior of the crew and fellow passengers to be relatively considerate, even if they’re a little cramped and annoyed. (You have to factor in that crying baby three rows back. It’s not the baby’s fault, after all.)Now consider were you’re seated on the airplane. Are you in first class or coach? That’s the grade!Within software developments we also have grades and quality issues.A quick, cheap software fix may be considered low grade, but it can still be a high-quality software solution because it satisfies the scope of the simple project. On the other hand, the rinky-dink approach won’t work during the development of a program to track financial data through e-ecommerce solutions for an international company.During the planning process, one goal of stakeholder analysis is to determine the requirements for quality and grade.6.5 Working with a Quality policyA quality policy isn’t a policy that’s “real good.”A quality policy is an organization-wide policy that dictates how your organization will plan, manage, and then control quality in all projects. This policy sets the expectations for your projects, and everyone else’s, for metrics of acceptability.Quality policies fall under the big umbrella of quality assurance. QA is an organization-wide program, the goal of which is to improve quality and to prevent mistakes.So who decides what quality is and what’s bunk? You might guess and say the customer, which to some extent is true, but generally the quality policy is set by management. The quality policy can be written by the geniuses within your organization, or your organization may follow a quality system and the proved quality approaches within these systems. For example, your company might participate in any number of proprietary and nonproprietary organizations, thereby pledging to adhere to their quality policies. The following sections discuss a few of them.Working ISO programsThe International Organization for Standardization(ISO) is a world wide body with153 members that convenes in Geneva, Switzerland. The goal of the ISO is to set compatibility standards for all industries, to establish common ground, and to maintain interoperability between businesses, countries, and devices.In case you’re wondering, the abbreviation for the international Organization for Standardization is ISO, not IOS. This is because of all the different countries represented and the varying languages; they decided to use the abbreviation of ISO taken form the Greek isos, which means equal.There are many different ISO programs, but the most popular is ISO 9000. An ISO 9000-certified organization focuses on business-to-business dealing and striving to ensure customer satisfaction. An ISO 9000-certified organization must ensure that it: Establishes and meets the customer’s quality requirements. Adheres to applicable regulatory requirements. Achieves customer satisfaction throughout the project. Takes internal measures to continually improve performance, not just once.You can learn more about ISO programs and how your organization canparticipate by visiting their Web site: .Visit these Web sites for more assistance with quality management:Getting a total Quality Management workoutThe U.S. Naval Air Systems Command originated the term Total QualityManagement as a means of describing the Japanese-style management approach to qualityimprovement.TQM requires that all members of an organization contribute to quality improvements in products, services, and the work culture. The idea is that if everyone is involved in quality and works to make the total environment better, then the services and products of the organization will continue to improve.In software development, TQM means that the entire team works to make the development of the software better, the process from start to completion better, and the deliverable better as well. TQM is largely based on W.Edwards Deming’s 14 Points for Quality. Here’s how Deming’s 14 points and TQM are specifically applicable to software development(you can find out more about W.Edwards Deming in the nearby sidebar, “W.Edwards Deming and the software project manager”):Create constancy of purpose for improving products and services. Every developer must agree and actively pursue quality in all of his or her software creation, testing, and development.Adopt the new philosophy. This philosophy can’t be a fad. The software project manager has to constantly motivate the project team to work towards quality.Cease dependence on inspection to achieve quality. Software development has tradition of coding and inspection, and then reacting to errors. This model is dangerous because developers begin to lean on the testing phase to catch errors, rather than striving to incorporate quality into the development phase. As a rule, quality should be planned into software design, never inspected in.End the practice of awarding business on price alone; instead, minimize total cost by working with a single supplier. The idea here is that a relationship will foster a commitment to quality between you and the supplier that’s a bit more substantial than an invoice and a check.Constantly strive to improve every process for planning, production, and service. Quality planning and delivery is an iterative process.Institute training on the job. If your software developers don’t know how to develop, they’ll certainly create some lousy software. If your team doesn’t know how to do something, you must train them.Adopt and institute leadership. The project manager must identify how to leadand motivate the project team, or the team may lead itself, remaining stagnant.Drive out fear. Are your software developers afraid of you? If so, how can they approach you with ideas for quality improvements, news on development, and flaws they’ve identified within the software? Fear does nothing to improve quality.为软件质量制定计划在这一章中我们将讨论：在软件工程中为质量下定义，遵循你所在团队的质量方针，创造一个质量管理计划，弄清楚时间和成本上的变化会对软件质量有何影响。

外文原文Caching Function with the Creation ofHigh Performance WebJonothon Ortiz, 《Web Developers Guide (VBL)》i.IntroductionSince the birth of the Internet, IT and development staff has been facing such problems, that is, how to create rapid response to user requests for Web applications, especially if the server is processing a large number of requests can respond quickly to user requests for Web applications. model provides many buiblt-in functions to enhance performance, caching is one of the important functions.ii.BriefIn practice, the generation of high performance, Scalable Web applications most important factor is one of the first to request these items will be stored in the Web services Treasury or request for a stream of other software, such as proxy servers or browsers, to avoid re-establish previous request to meet the information, particularly those requiring a large number of processor time or resources. This is commonly referred to the cache, It allows the use of a variety of technologies across HTTP request page output or storage application data and its reuse, Servers do not need to re-create information, thereby saving time and resources.provides two can be used to build high-performance Web caching application types. The first one is called the output cache, It allows dynamic page or user control response stored in the output stream (launched from the server to request the browser) with any H cache function of equipment. When behind at the time of the request,the non-implementation of a page or user control code for the output buffer to meet the request. The output buffer cache may be targeted at the entire page, and can also be part of page. The second type of cache is a traditional application data cache, It can be used to programmatically arbitrary object (eg, data sets) storage memory to the server, so that Application procedures can save these objects re-establish the necessary time and resources. iii.Cache whole pagepermitting the browser function of the mechanism for dynamic caching the entire page response, These mechanisms refers browsers, proxy servers and application procedures for the presence of the Web server. It provides a powerful means to improve Web application performance. This technique is called the output cache, which allows the cache to meetbehind specific page on the request, so that When behind the request at the time of the initial operation will be no need to create code pages. Use of the technology to cache site most frequently visited pages can be fully enhance the throughput of the Web server (usually per second Number of requests). In a busy site, if Cache been frequently visited pages, and even if only a minute, can greatly improve performance. When pages in the output cache, on the pages of the additional request is treated Cache, it is not enforced and recompile the code to create pages.When the operation page output cache, they can choose a high-level declarative API or low-level programming API. You can OutputCache directive will be included in the page. Aspx use of the former documents. OutputCache Order to meet page output cache when almost all the normal demand.Output Cache complete syntax is as follows :<%@ OutputCache Duration=”#ofseconds”Location=”Any|Client|Downstream|Server|None”Shared=”True|False”VaryByControl=”controlname”VaryByCustom=”browser|customstring”VaryByHeader=”headers”VaryByParam=”parametername”%>The parameters are as follows :●DurationPage or user control caching for time (in seconds). In a page or user control on the setting up of the attributes of the object from the HTTP response to the establishment of an outdated strategy Cache will automatically page or user control output.●LocationLocation OutputCache one of the enumeration values. designated location in which cache pages, default values for Any.●SharedA Boolean value to determine whether user control output can be shared by a number of pages. The default value to false.●VaryByControlA semicolon-separated list of strings used to change the user controls the output buffer. These strings on behalf of the user controls the stated server controls the ID attribute values.●VaryByCustomSaid that since the output buffer requirements definition arbitrary text. If given the attribute value is browser, the cache will be with the browser name and major version information are different.●VaryByHeaderSemicolon-separated list of HTTP headers, the output cache for change. When this attribute is set to more headers, for each designated headers, the output cache contains a request for documentation of the different versions.●VaryByParamSemicolon-separated list of strings, the output buffer for a change. By default, these strings using the GET method attributes Send inquiries string value counterparts, or with the use of this method POST parameters counterparts. When this attribute is set to more parameters, for each designated parameters, output buffer includes a request for documentation of the different versions. Possible values include none, * and any effective inquiry string or POST parameter name.The following commands (as in. Aspx document pm) for the dynamically generated page set the output buffer of 60 seconds when due time :<% @ OutputCache Duration=”60” VaryByParam=”None”%>When using the @ OutputCache directive. Duration and VaryByParam attribute is essential. If they are not included, the first page request analyzers errors will occur. If you do not want to use the VaryByParam attribute function, its value must be set to None.also includes a set of APIs. By HttpCachePolicy class programming to control the output cache pages due time and strategy slightly. through the use of such attributes. can attribute Page Object Access from the property.For example, The following code (when including the code page statement or block its code hidden category pm) HttpCachePo method for dynamically generated page set up 60 seconds due time :Response. (60);Once the opening of the output buffer, This page is the first one in HTTPGET request within the specified time of its dynamic content placed in the output buffer. Output caching meet face after page of GET, HEAD, or POST request until more than a specified amount of time.Programmers can also use statement or programming in the manner, at the request flow to enable or disable the cache support equipment for the page output cache. In the @ OutputCache page directive, Location attribute can be used to designate whether the page output caching proxy server, browser client, the original Web server or all of these equipment,or the equipment in the cache of any one. Programming can be implemented in the same operation, use methods appropriate for the specified page When the HttpCacheAbility enumeration value.Also with inquiries from the string parameters GET request with parameters or Form POST request generated in response to Jin OK Cache, However, we must use the @ OutputCache directive VaryByParam attribute to the opening of transmission parameters Cache.We need to be aware : Programming approach to the output buffer for any operation to be. aspx document code block statement, or with the. aspx files associated with the code for hidden category.iv.Resolution CacheSometimes, no caching the entire page, but may need to create dynamic each request certain parts of the page. Resolution Cache Cache including allowing users control any response to the request for production of the parts. In these circumstances, need to spend time marking require substantial resources to construct server with page requests linked to the object or data. Once the identification of these projects, on the Web through user controls Form Creating these items to them from other parts of the page separated, Then in a prescribed period of time on these items cache to save server resources. This is commonly referred to fragment cache.This technology allows certain parts of the page (such as database queries) and other parts of the page separation. Programmers can choose to allow for dynamically generated for each request requires less server resources of the page.Once the logo to the page cache, and create a right for each part of the Packaging user controls, These users must determine the Cache Control Strategy. When hidden code to create user category Controls, use @ OutputCache directive to the installation of these statements strategy PartialCachingAttribute or use similar methods to install such programming strategy.If, for example, the following command will include the user controls (ASCX) to the top The controls were a version of the output buffer storage of 120 seconds :<% @ OutputCache Duration=”120” VaryByParam=”None”%>Likewise, the use of hidden code development method development of the user controls, the following attributes will be included in the category statement yuan data, Control version of the output buffer storage of 120 seconds.[PartialCaching(120)]If the use of these technologies in any one, when the requesting user controls include the page, users will only cache control.If the page statement and the use of the output buffer for the specified user controls, pages will be based on the analyzer controls the creation, Object of two types of a type of example. If built in a statement users Controls will add StaticPartialCachingControl object; If the use of LoadControl ways to programmatically create user controls. Partial-CachingControl object is added. Thus, when the request for the page, if the page is not cached. Add analyzer will target users control the pages of control hierarchy structure as a logical location.Because the user controls can be nested in the other page server controls, So also can be nested Add output has been cached user controls. This means that the output cache can be included in the instructions on page output caching user controls, or included in the output buffer as another part of the user controls which users control.v.Caching data applicationsprovides a powerful, easy-to-use caching mechanisms, Allow will need a lot of server resources to create the object stored in the memory. It is achieved by the Cache class, and examples of each application-specific, its survival depends on the application of survival. Re-start the application process, will be re-created Cache object.Cache design category is intended to facilitate use. Through the use of market value and the key pairs can be placed in the cache items and retrieve them at a later date.Cache class provides a simple interface definition from the cache. It also provides a powerful feature allows custom items and Cache Cache time. For example, when the lack of system memory, Cache automatically remove rarely used or unimportant items to allow the use of memory to handle the large number of requests. This technique is called liquidation. This is to ensure that non-cached data is not current use of valuable server resources in a different form.When liquidation, the program can give instructions Cache certain items than other items higher priority. To instructions specific items other than having a higher or lower importance need to use method or methods to add an item designated C acheItemPriority enumeration value.When using the Add method or methods to Insert items added to the cache, but also due to the establishment of strategic items. Programming can absolutionExpiration parameters through the use of the definitions of survival, The parameters DataTime type, it designated for the exact expiration of the time. SlidingExpiration can use parameters, the parameters of TimeSpan types. It allows programmers visit items under the designation of the time before the expiration of the running time. Once it expired, and put it removed from the cache. Attempting to retrieve its value will return null, unless it was re-added to the Cache. WereCache for storage in the easy to miss (for example, those who frequently updated data or only those within a certain period of time effective), the setting up of a mature strategy, as long as these items remain at the latest data. They will be retained in the cache were. For example, suppose the preparation of an application, The application procedure from a frequently updated Web site access to data to track sports score, So long as the source of a Web site contest Scores not change, we can match these cache. In this case, according to the Web site to update the score to set the frequency due strategies. Code can be prepared to determine whether Cache is the latest score, if the score is not the latest, then the source code from the Web site updated score.Also under also allows external files, directories or another definition Cache Cache items arrival. These documents called dependence on key items and items. If the change in dependency, failure cache item was removed from the cache. Were Able to use the technology in the above changes to the source data from the Cache Remove these items. If, for example, the preparation of an XML document handling financial data applications, and presents it in graphic, was able to pass the document to insert data in the cache and XML documents on a reservation items. When the updated document, removed from the cache, application procedures, re-read the document, then insert it in a new version.vi.Enhance the performance of other methodsIn addition to high-speed caching, also built a number of other functions can be optimized Web applications, Performance enhancing procedures, which are listed below for reference part.⏹When not using conversational state banned it.⏹Conversational carefully selected to provide state procedures.⏹Avoid unnecessary server and from the process.⏹Use to avoid unnecessary and from the process of implementation of the treatment.⏹the use and possible at the appropriate time to use server controls.⏹Avoid excessive use of server controls View state. Livanos methods used strings.⏹Do not rely on the code anomalies.⏹Data Access using SQL stored procedures.⏹the appropriate use of the Common Language Runtime garbage recycling and automatic memory management.⏹If a large-scale Web applications, may consider implementing pre-approved translation.necessary adjustment assistance application process each thread of a few.vii.Conclding remarksThis paper mainly describes the Cache technology, respectively for the three types of cache of detailed, Finally, it provides some optimization Web application performance methods.中文翻译一、引言自从Internet诞生以来，开发人员和IT人员就一直面临着这样的难题，即如何创建快速响应用户请求的Web应用程序，尤其是即使服务器正在处理大量请求时也能快速响应用户请求的Web应用程序。