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高级双语阅读指导师英语自我介绍全文共5篇示例，供读者参考高级双语阅读指导师英语自我介绍篇1thank you for giving me the chance to interview and it is my pleasure to introduce myself to you. my name is lifeng. i major in and i will graduate from the .. medical university in july, 20xx. hope a chance to work and develop in your department.during the past three years, under the strict guidance of my tutor, professor in college of , i have learned systematically the theory of profession and got the basic manipulative skills about .. with the help of my supervisor, i have successfully finished the subject and grasped some experimental skill , such as cell culture, dna extraction and other molecular biology technique; abstraction, separation, .. ..during three-year study in research, i studied hard and strived for excellence in our field. i benefit from working together with excellent colleague. i developed quality of diligence, responsibility, kindness and honesty. my internship in college of .. could qualify me for this job, and i believe i can be fit for the position quickly. i am looking forward to working in yourdepartment. if i am admitted, i will be thankful and try my best to work for you.thank you very much.高级双语阅读指导师英语自我介绍篇2good afternoon! professors ：i am honored to introduce myself. my name is zjz, 32years old. in the year 20xx and 20xx, i received my bachelor degree and master degree in sdust.i major in mathematics. after my graduation, i got a job in qingdao technological university. in the past 3 years, i was involved in china undergraduate mathematical contest in modeling, and the teams i directed was rewarded the first prize in shandong contest district both in this year and last year.however, with time going on, the more i experienced, the clearer i realized that i am lack of knowledge. i really interested in economics and management. i find that the similar and problems rise in my study subject, so i’m eager to cognize more about this field and i hope i can study further in beihang university.so i am standing here now. i am really excited. i believe what i am doing is a right thing.that’s all. thank you for giving me the chance to present myself!高级双语阅读指导师英语自我介绍篇3good morning professorsit’s my honor to have opportunity for this interview. my name is zhong keyuan, 27 years old. my hometown is ganzhou in jiangxi province. i received my bachelor degree in jiangxi normal university majored in geographical science. now i am studying in fujian normal university.my major is natural resources.i have acquired some basic knowledge of distributed hydrological erosion model during my graduate years and published a research paper in journal of natural resources. i have built up a daily runoff and sediment annualized agricultural non-point source pollution model (annagnps) in shanmei reservoir basin in fujian province. and i'm interested in the uncertainty of the distributed hydrological erosion model and i want continue my research.i hope have chance to have further study in this university. that’s all, thank you!高级双语阅读指导师英语自我介绍篇4my name is , this year 27 years old. july me from * * normal school art teacher art professional inside the plan at graduation. from to within country no longer zifeisheng bag distributive, that i should go up with the sun most glary vocation over. fortunately, tattenai machang small teachers is insufficient, the people in this small introduction, i served as a year of temporary substitute teacher.recall that time which was both sweet and good, although substitute a low salary, but listen students around the side teacher and teacher growled and looked at the pairs of eyes, the full trust every childishness little face, all the unpleasant life all suddenly vanished. i wanted to, even if it does not become a full member, as long as the school needs, is when the lifetime class teacher i also willingly. and behold, since countries began to repel temporary and class teacher, received the school verbally notify after, i was reluctant to part with the mood, quietly left school.today, i want to pass the exam again on the rostrum desire is so urgent! my family has three sisters, two sisters working outside, in order to take care of elderly parents already, i always stay in their side. i have open shop, first business handicraft, again after business clothing. but no matter how business handy,when a glorious people's teacher has always been my dream of fundamentality and wish to their life work to pursue career. i have participated in the exam, but are due to various reasons and failed to realize the dream, but i decided, as long as the opportunity, i have been exam go on until the ideal realization so far.now of i, after the test of life than my rival in age i no longer have an advantage, but i had a more than they are in children's love, patience and responsibility, a more mature andself-confident.the teachers in this profession is sacred and great, he asked the teacher not only need have a wealth of knowledge, also have a lofty sentiment. therefore, reading normal, i pay great attention to their all-round development, extensive training their hobbies, and learning has the specialty, accomplish except the good at painting and calligraphy outside, still can sing, can speak, speak. learning for division, high only body sudoku for fan in knowledge-based learning at the same time, i pay attention to cultivating their own noble moral sentiment, consciously bound, observe social ethics, no bad habits and behavior. i think these are an education workers should have the least knowledge.if, i passed the interview, become numerous teachers team members, i will continue to study hard and work hard, for the hometown of education and contribute their efforts, disappoints engineers of human souls this glorious title.高级双语阅读指导师英语自我介绍篇5general introductioni am a third year master major in automation at shanghai jiao tong university, p. r. china. with tremendous interest in industrial engineering, i am writing to apply for acceptance into your ph.d. graduate prograeducation backgroundin , i entered the nanjing university of science & technology (nust) -- widely considered one of the china’s best engineering schools. during the following undergraduate study, my academic records kept distinguished among the whole department. i was granted first class prize every semester,in , i got the privilege to enter the graduate program waived of the admission test.at the period of my graduate study, my overall gpa(3.77/4.0) ranked top 5% in the department. in the second semester, i became teacher assistant that is given to talented and matured students only. this year, i won the acer scholarship as the one and only candidate in my department, which is the ultimate accoladefor distinguished students endowed by my university. presently, i am preparing my graduation thesis and trying for the honor of excellent graduation thesis.research experience and academic activitywhen a sophomore, i joined the association of ai enthusiast and began to narrow down my interest for my future research. with the tool of opengl and matlab, i designed a simulation program for transportation scheduling syste it is now widely used by different research groups in nust. i assumed and fulfilled a sewage analysis & dispose project for nanjing sewage treatment plant. this was my first practice to convert a laboratory idea to a commercial product.in retrospect, i find myself standing on a solid basis in both theory and experience, which has prepared me for the ph.d. progra my future research interests include: network scheduling problem, heuristic algorithm research (especially in ga and neural network), supply chain network research, hybrid system performance analysis with petri nets and data mining.。
介绍自我英语演讲稿介绍自我英语演讲稿5篇当来到一个新环境时，我们通常会被要求作自我介绍，通过自我介绍可以让他人了解我们。
但是自我介绍有什么要求呢？以下是小编为大家整理的介绍自我英语演讲稿5篇，欢迎阅读，希望大家能够喜欢。
介绍自我英语演讲稿5篇1I'm ___ class of ___, common household's daughter, my parents is assistant, life is general, also because of this, there may be little genetic relationship, my personality is quite introverted.This year in September, I come to guangzhou college, this is my first time to leave my parents give far door. See side come and go, enthusiasm is bold and unrestrained, cheerful talkative classmates,I am deeply into his own character of pressure, although I didn't think that my character to have what not good.Because introverted, I introduce myself in class sound when very small, so that his classmates don't know me, Because introverted, I dare not and not too familiar classmate say hello, so I often come alone walking alone, Because introverted, I dared not participate in those who have an interview activity that I've lost self-e_ercise opportunities. I even worried, I later how to obtain employment? How to recommend myself?There is no matter that can't be solved, also did not cross over the candy. The formation of character is accumulated, to solve it is never happen overnight, I must be patient. The university is a self-training, improve your own platform, there is a lot of classmates, for me an outside resident students, now turned into inside the resident students, should be a very goodcharacter training opportunities.Let the past be the past, let now compose the future. University is the life of another a start, wish all of us as a freshman students can round their beautiful university dream, fulfillment metamorphosis.介绍自我英语演讲稿5篇2Hello everyone, my name is Lee. This is really a great honor to have this opportunity, and I believe I can make good performance today. Now I will introduce myself briefly. I am 20 years old，born in Guangdong province, south of China, and I am a senior student at Guangdong __University. My major is English. And I will receive my bachelor degree after my graduation in June.In the past four years, I spent most of my time on study. I passed CET4 and CET6 with a ease and acquired basic theoretical and practical knowledge of Language. Besides, I have attended several Speech competition held in Beijing, which really showed our professional advantages. I have taken a tour to some big factories and companies, through which I got a deep understanding of English for application.Compared to developed countries, unfortunately, although we have made e_traordinary progress since 1998, our packaging industry is still underdeveloped, messy and unstable, and the situation of employees in the field is awkward. But I have full confidence in its bright future if only our economy can be kept at the growth pace still. I guess you may be interested in why I choose this job. I would like to tell you that this job is one of my lifelong goals.If I can work here,I will work hard. As to my character, I cannot describe it well, but I know I am optimistic and confident.Sometimes I prefer to stay alone, reading and listening to the music, but I am not lonely, for I like to chat with my classmates about almost everything. My favorite pastime is to play volleyball, to play cards or to surf online. From life at university, I learn how to balance study and entertainment. By the way, I was an actor in our amazing drama club. I have a few glorious memories on stage.介绍自我英语演讲稿5篇3Good morning, everyone! It is really my honor to have this opportunity for an interview. I hope I can make a good performance today. I'm confident that I can succeed. Now I will introduce myself briefly. I am 26 years old, born in Shandong province. I graduated from Qingdao University. My major is electronics. And I got my bachelor degree after my graduation in the year of 20xx. I spent most of my time on study, and I’ve passed CET-6 during my university. And I’ve acquired basic knowledge of my major. It is my long cherished dream to be an engineer and I am eager to get an opportunity to fully play my ability.In July 20xx, I began working for a small private company as a technical support engineer in Qingdao city. Because there was no more chance for me to give full play to my talent, so I decided to change my job. And in August 20xx, I left for Beijing and worked for a foreign enterprise as an automation software test engineer.Because I want to change my working environment, I'd like to find a job which is more challenging. Moreover，Motorola is a global company, so I feel I can gain a lot from working in this kind of company. That is the reason why I come here to compete for this position. I think I'm a good team player and a person ofgreat honesty to others.Also，I am able to work under great pressure. I am confident that I am qualified for the post of engineer in your company.That’s all. Thank you for giving me the chance.介绍自我英语演讲稿5篇4Good morning/afternoon/evening, my name is___ . It is really a great honor to have this opportunity/chance to introduce myself. I would like to answer whatever you may raise, and I hope I can make a good performance today.I am a third year master major in automation at Shanghai Jiao Tong University, P. R. China. Withtremendous interest in Industrial Engineering, I am writing to apply for acceptance into your Ph.D. graduate program.In 1995, I entered the Nanjing University of Science & Technology (NUST) -- widely considered one of the China’s best engineering schools. During the following undergraduate study, my academic records kept distinguished among the whole department. I was granted First Class Prize every semester,In 1999, I got the privilege to enter the graduate program waived of the admission test.At the period of my graduate study, my overall GPA(3.77/4.0) ranked top 5% in the department. In the second semester, I became teacher assistant that is given to talented and matured students only. This year, I won the Acer Scholarship as the one and only candidate in my department, which is the ultimate accolade for distinguished students endowed by my university. Presently, I am preparing my graduation thesis and trying for the honor of Ecellent Graduation Thesis.Research e_perience and academic activityWhen a sophomore, I joined the Association of AI Enthusiastand began to narrow down my interest for my future research. With the tool of OpenGL and Matlab, I designed a simulationprogram for transportation scheduling system. It is now widely used by different research groups in NUST. I assumed and fulfilled a sewage analysis & dispose project for Nanjing sewagetreatment plant. This was my first practice to convert a laboratory idea to a commercial product.In retrospect, I find myself standing on a solid basis in both theory and e_perience, which has prepared me for the Ph.D. program. My future research interests include: Network Scheduling Problem, Heuristic Algorithm research (especially in GA and Neural network), Supply chain network research, Hybrid system performance analysis with Petri nets and Data Mining. 介绍自我英语演讲稿5篇5Good morning / afternoon, dear Ms. / Mr. __ and all my classmates.I feel very happy to introduce myself. I come from Tianjin, a large and beautiful seashore city. It is municipality directly under the Central Government. As a guard city of Beijing, Tianjin has its special politic function. It also once played a great role in Chinese economic development after 1949. It is famous for its industry.As an old city, Tianjin has many traditional features. Firstly, its Chinese folks art -- crosstalk (相声) is very famous. Guo Degang is my town fellow (老乡). Secondly, there are famous universitites in Tianjin such as Nankai University. Thirdly, it is a place abounding in celebrities: Zhou Enlai, Wen Jiabao and many other famous people from Tianjin. Thirdly, TIan jin is well-known for its food. For e_ample, Goubuli stuffed bun (狗不理包子), 18th street manual twist (十八街麻花), Erduowen fried rice cake (耳朵眼炸糕) and so on. What's more, Tianjin is a travel city. The Nightview ofHai River is very popular among travellers.All in all, Tianjin is a great city. I believe it will become better and better. I hope you will go to visit it with me sometimes. Thank you very much!。
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Petri网论文：基于Petri网的几个并发问题的建模与分析【中文摘要】Petri网不仅可以采用可视化图形描述而且可被形式化的数学方法所支持,是一种形式化、图形化的分布式系统建模和分析工具。
它不但能够精确地分析系统的静态特性,而且能够很好地分析系统的动态行为性质,从而很好地刻画系统的动态行为、分析系统的性能。
它既可采用形式化直观的图形表示,又可以引入许多数学方法对其性质进行分析与验证。
目前,大多数的软件系统都是并发系统,并发是衡量系统运行效率高低的一个参数标准。
为了达到“事半功倍”的效果,现在的系统环境越来越需要并发,只有这样才能更好地利用系统资源环境,才能使一个系统具有更强的竞争力。
Petri网作为一个优秀的形式化描述和分析工具,能很好地描述和分析这类系统。
采用软件形式化技术,不仅有利于开发人员之间的沟通,提高软件的可靠性,而且可以尽可能地缩短开发的总体时间,减少软件设计早期阶段的错误。
本文的主要工作如下:(1)在Petri网下对哲学家就餐问题模型进行了分析。
哲学家就餐问题是描述在共享资源下同步与并发的经典案例,活性与无饥饿性是求解此问题的前提,效率是基本要求。
由于对资源的竞争使几个哲学家不可能同时处于就餐状态,在考虑公平性的情况下定义了延迟Petri网...【英文摘要】Petri nets can not only use visual graphic description, but also can be supported by formal mathematical methods, it is a kind of formalized, graphical distributedsystem modeling and analysis tools. It can analyze system static characteristics accurately and analyze system dynamic behavior well, thereby good depicting system dynamic behavior and analyzing system performance. It may adopt formalized visual graphics and introduce many mathematical methods to analyze and verify its properties.At present, ...【关键词】Petri网异步并发形式化方法 S-不变量建模系统分析【英文关键词】Petri net Asynchronous concurrent Formal methods S-invariant Modeling System analysis。
Chapter 17Petri Net Analysis17.1INTRODUCTIONPetri net analysis (PNA)is an analysis technique for identifying hazards dealing with timing,state transitions,sequencing,and repair.PNA consists of drawing graphical Petri net (PN)diagrams and analyzing these diagrams to locate and understand design problems.Models of system performance,dependability,and reliability can be developed using PN models.PNA is very useful for analyzing properties such as reachability,recoverability,deadlock,and fault tolerance.The biggest advantage of Petri nets,however,is that they can link hardware,software,and human elements in the system.The PNA technique may be used to evaluate safety critical behavior of control system software.In this situation the system design and its control software is expressed as a timed PN.A subset of the PN states are designated as possible unsafe states.The PN is augmented with the conditions under which those states are unsafe.A PN reachability graph will then determine if those states can be reached during the software execution.17.2BACKGROUNDThe PNA technique falls under the system design hazard analysis type (SD-HAT)and should be used as a supplement to the SD-HAT analysis.Refer to Chapter 3for a description of the analysis types.The purpose of the PNA is to provide a tech-nique to graphically model systems components at a wide range of abstraction levels 307Hazard Analysis Techniques for System Safety ,by Clifton A.Ericson,IICopyright #2005John Wiley &Sons,Inc.308PETRI NET ANALYSISin order to resolve system reliability,safety,and dependency issues.The graphical model can then be translated into a mathematical model for probability calculations.Petri nets can be used to model a system,subsystem,or a group of components. PNA can be used to model hardware or software operation or combinations thereof. To date,the application of PNA for system safety use has been limited to the exam-ination of software control systems.Its use has rarely been applied to large systems. PNA can be used to develop reliability models of system operation.The significant advantage of the technique is that it can be applied to a system very early in development and thereby identify timing issues that may effect safety early in the design process.PNA application helps system developer’s design in safety and system quality during early development,eliminating the need to take corrective action after a test failure or mishap.The PNA method is somewhat difficult to learn,understand,and master.A graduate-level understanding of mathematics and computer science is needed for the application of PNA.The analyst must master the technique and have a detailed knowledge of the process being modeled.The PNA technique is suited for use by theoretical mathematicians.The PN model quickly becomes large and unwieldy as system size increases and is therefore usually only used on small system applications.The use of PNA is not widespread in the system safety discipline because of its difficulty to use,its limitation to smaller problems,and its limitation in scope to timing-type problems.PNA is highly specialized and only assists in a certain niche of potential safety concerns dealing with timing and state reachability.The technique is only recommended for special design safety concerns.17.3HISTORYThe concept of Petri nets has its origin in Carl Adam Petri’s doctoral dissertation Kommunikation mit Automaten submitted in1962to the faculty of Mathematics and Physics at the Technische Universita¨t Darmstadt,Germany.His thesis devel-oped this graph-based tool for modeling the dynamics of systems incorporating switching.Subsequent research by many individuals has provided the means for using Petri’s concepts as the basis for system modeling in many different appli-cations,such as reliability,dependency,safety,and business models.17.4DEFINITIONSIn order to facilitate a better understanding of PNA,some definitions for specific terms are in order.The following are basic PNA terms:Transition Represents a system event that must occur.Transitions contain a switching delay time.When all of the inputs to the transition have a token,the transition event is enabled,and it occurs or switches after the given delay time.The delay time represents the actual system operational design.A delay timeis placed in each transition node.Immediate transitions have a delay time equal to zero (D ¼0).When the transition node switches or fires ,all input nodes lose their token,and all output nodes receive a token.Place Used to represent the input and output nodes to a transition.Places containthe tokens.Token Represents timing in the system logic.As a PN model develops,the tokensbuild sequencing into the model.Tokens are analogous to currency;they are used for transactions.Connecting edge Connects the places and transitions together to build the logicalmodel.State Static condition (or state)of the PN model before and after the firing of atransition.A PN model will have a finite number of states,based on the model design.Reachability System can have many different possible states;reachability refersto the systems capability to reach any or all of those states during operation.As designed,the system may not be able to reach some states.Repair Refers to the capability to physically repair a failed component and restoreit to an operational state.17.5THEORYThe PNA method utilizes a diagram or directed graph that portrays in a single diagram the operational states of the system.The state diagram is flexible in that it can serve equally well for a subsystem or an entire system.The diagram provides for representation of system states,transitions between states,and timing.Figure 17.1illustrates the overall PNA process.17.6METHODOLOGYA Petri net is a graphical and mathematical modeling tool.It consists of places,tran-sitions,and arcs that connect them.Input arcs connect places with transitions,whilePetri NetModelSystem & State Probability CalculationsData• Failure Rates • Repair RatesFigure 17.1PNA process.17.6METHODOLOGY 309310PETRI NET ANALYSISoutput arcs start at a transition and end at a place.There are other types of arcs,for example,inhibitor arcs.Places can contain tokens;the current state of the modeled system(the marking)is given by the number(and type if the tokens are distinguish-able)of tokens in each place.Transitions are active components.They model acti-vities that can occur(the transitionfires),thus changing the state of the system(the marking of the Petri net).Transitions are only allowed tofire if they are enabled, which means that all the preconditions for the activity must be fulfilled(there are enough tokens available in the input places).When the transitionfires,it removes tokens from its input places and adds some at all of its output places.The number of tokens removed/added depends on the cardinality of each arc.The interactive firing of transitions in subsequent markings is called token game.Figure17.2shows the symbols utilized in comprising a PN model.All PN models can be constructed with just these components and using thefiring rules listed below.A PN is a bipartite directed graph(digraph).It consists of two types of nodes:places (drawn as circles),which can be marked with tokens(drawn as a dot),and transitions (drawn as squares or bars),which are marked by the time,D,it takes to delay the output of tokens.If D¼0,the transition time is immediate;otherwise,it is timed.PNs dealing with transition times are often referred to as timed PNs. Timed Petri nets are models that consider timing issues in the sequencing.The prac-tice of integrating timed Petri nets with software fault tree analysis has recently become popular.The movement of tokens is governed by thefiring rules as follows:1.A Transition is enabled when all of the places with edges pointing to it aremarked with a token.2.After a delay D!0the transition switches orfires.3.When the transitionfires,it removes the token from each of its input placesand adds the token to each of its output places.4.A place can have multiple tokens.5.The number of tokens in a PN is not necessarily constant.Figure17.2PN model symbols.6.Tokens move along the edges at infinite speed.7.The transition time D can be either random or deterministic.The PNA method has a static part and a dynamic part.The static part consists of the places,transitions,and edges.The dynamic part involves the marking of places with the tokens when the transition firing occurs.In the PN model,places represent events that correspond to discrete system states.The transitions represent logic gates.The marking of a PN model at a given moment represents the state at that moment in time.Figure 17.3shows an example PN model with three transition states.In state 1,place 1has a token but place 2does not.Nothing can happen until place 2receives a token.In state 2,place 2receives a token.Now transition D1has both inputs fulfilled,so after delay D1it fires.State 3shows the final transition,whereby D1has fired,it has removed the two input tokens (places 1and 2)and given an output token to place 3.Figure 17.4shows another example PN model with two transition states.This example shows how places can have multiple tokens,and how tokens are added and subtracted depending on the model.In this example,transition D1has tokens for all input places in state 1,so it therefore fires and transitions into state 2.State 2shows that each input place loses a token and each output place receives a token.Multiple tokens can be used for modeling counting loops or redundant components ina2State 1 State 3State 2 Figure 17.3Example PN model with three transitionstates.State 1State 2Figure 17.4Example PN model with multiple tokens.17.6METHODOLOGY 311system design.Transition D1cannot fire again because all of its inputs do not have tokens now.Figure 17.5shows how AND gates and OR gates are modeled via PN models.Note that the transitions have a delay time of zero and are therefore immediate.A powerful feature of PNs is their corresponding state graphs,otherwise referred to as reachability graphs (RG).Reachability graphs show all of the possible system states that can be reached by a PN model.Knowing which states can be reached and which cannot is valuable information for reliability and safety evaluations.For example,it is important to know if a system can reach a suspected high-risk state.Figure 17.6shows an example PN model along with its corresponding reach-ability graph.In this RG state 1is the initial state,with places 1,2,and 4each having a token.State 2shows the result of transition D1.State 3shows the result when transition time D2,D3,while state 4shows the result when transition time D2.D3.With five places in this model,one might assume that with each place having a binary value of 0or 1that there would be 25¼32possible states.But,as shown by the reachability graph only four states are actually reachable.Figure 17.7shows a PN model for a system design with two redundant com-ponents with repair.This system is comprised of two redundant components operat-ing simultaneously.Successful operation requires that only one component remain functional.When a component fails,it undergoes repair.If the second component fails while the first is being repaired,then the system is failed.Note the special PN terminology in this PN model.L1indicates life operation until random failure of component 1,while R1indicates component 1during repair duration.The /2notation indicates that two tokens are required for this transition to occur.OR GateAND Gate Figure 17.5PN model of AND gate and ORgate.Figure 17.6PN with reachability graph.312PETRI NET ANALYSISFigure 17.8shows the RG for the PN model in Figure 17.7.This type of RG is referred to as a cyclic RG with an absorbing state.Note that with two components in this system,four possible states are expected,but in this case the eventual marking of place 6defines a fifth state.Note also,that since place 5requires two tokens for switching these state numbers are nonbinary.The PNA method may be used to evaluate safety critical behavior of control system software.In this situation the system design and its control software is expressed as a timed PN.A subset of the PN states are designated as possible unsafe states.The PN is augmented with the conditions under which those states are unsafe.A PN reachability graph will then determine if those states can be reached.If the unsafe cannot be reached,then the system design has been proven to not have that particular safety problem.17.7EXAMPLESThe hypothetical missile fire control system shown in Figure 17.9will be used to demonstrate a PN model.System operation is as follows:1.The operator presses the arm button to initiate arming and firing process.6SystemDown 5Figure 17.7PN of two-component system with repair.Figure 17.8RG for two-component system with repair.17.7EXAMPLES 3132.When the computer receives arm button signal,the computer initiates asystem self-test to determine if the system is in a safe state and all arming and firing parameters are met.3.If the self-test is passed,the computer generates a fire signal when the firebutton is depressed;if the self-test does not pass,then firing is prohibited by the computer.Figure 17.10shows how a PN model might be applied to analyze an actual weapon system design.The PN model for the missile fire sequence reveals the following safety information:1.A valid fire signal requires three interlocks:arm command,fire command,andfire enable signal.Missile Fire Figure 17.9Example missile fire sequence system.Fire FireButtonFigure 17.10PN for missile fire sequence system.314PETRI NET ANALYSIS17.10SUMMARY3152.The computer is a single-point item that processes all three interlocks and,therefore,is susceptible to single-point failures,both in hardware and software.17.8ADVANTAGES AND DISADVANTAGESThe following are advantages of the PNA technique:1.PNs can be used to model an entire system,subsystem,or system componentsat a wide range of abstraction levels,from conceptual to detailed design.2.When a PN model has been developed for analysis of a particular abstraction,its mathematical representation can support automation of the major portions of the analysis.3.PNA is a good tool for modeling and understanding system operation.The following are disadvantages of the PNA technique:1.PNA only identifies system hazards dealing with timing and state changeissues.2.PNA is a limited hazard analysis tool because it does not identify root causes.3.PNA requires an analyst experienced in PN graphical modeling.4.PNA models quickly become large and complex;thus,it is more suitable tosmall systems or high-level system abstractions.17.9COMMON MISTAKES TO AVOIDWhenfirst learning how to perform a PNA,it is commonplace to commit some traditional errors.The following is a list of typical errors made during the conduct of a PNA:1.Not obtaining the necessary training.ing the complex PNA technique when a simpler technique might be moreappropriate.17.10SUMMARYThis chapter discussed the PNA technique.The following are basic principles that help summarize the discussion in this chapter:1.PNA models the timing and sequencing operation of the system.2.PNA is a tool for identifying a special class of hazards,such as those dealingwith timing,state transitions,and repair.316PETRI NET ANALYSIS3.PNA provides both a graphical and mathematical model.4.PNA only requires places,tokens,transitions,and connecting edges to modela system.5.PNA can easily become too large in size for understanding,unless the systemmodel is simplified.6.For system safety applications,PNA is not a general-purpose hazard analysistool and should only be used in situations to evaluate suspected timing,state transition,sequencing,and repair hazards.BIBLIOGRAPHYAgerwala,T.,Putting Petri Nets to Work,IEEE Computer,Dec.,85–94(1979). Malhotra,M.and K.Trevedi,Dependability Modeling Using Petri Nets,IEEE Trans.Reliability,44:428–440(1995).Petri Nets:Properties,Analysis and Applications,Proc.IEEE,77:541–580(1989). Schneeweiss,W.G.,Petri Nets for Reliability Modeling,LiLoLe,1999. Schneeweiss,W.G.,Tutorial:Petri Nets as a Graphical Description Medium for Many Reliability Scenarios,IEEE Trans.Reliability,50(2):June,159–164(2001).。
大学生英语自我介绍及翻译高校生英语自我介绍及翻译（精选20篇）高校生英语自我介绍及翻译篇3高校生英语自我介绍及翻译篇5高校生英语自我介绍及翻译篇7高校生英语自我介绍及翻译篇13高校生英语自我介绍及翻译篇14Good morning, my name is jack, it is really a great honor to have this opportunity for a interview, i would like to answer whatever you may raise, and i hope i can make a good performance today, eventually enroll in this prestigious university in september.now i will introduce myself briefly,i am 21 years old,born in heilongjiang province ,northeast of china,and i am curruently a senior student at beijinguni.my major is packaging engineering.and i will receive my bachelor degree after my graduation in june.in the past 4 years,i spend most of my time on study,i have passed CET4/6 with a ease. and i have acquired basic knowledge of packaging and publishing both in theory and in practice. besides, i have attend several packaging exhibition hold in Beijing, this is our advantage study here, i have taken a tour to some big factory and company. through these i have a deeply understanding of domestic packaging industry. compared to developed countries such as us, unfortunately, although we have made extraordinary progress since 1978,ourpackaging industry are still underdeveloped, mess, unstable, the situation of employees in this field are awkard. but i have full confidence in a bright future if only our economy can keep the growth pace still.i guess you maybe interested in the reason itch to law, and what is my plan during graduate study life, i would like to tell you that pursue law is one of my lifelong goal,i like my major packaging and i wont give up,if i can pursue my master degree here i will combine law with my former education. i will work hard in thesefields ,patent ,trademark, copyright, on the base of my years study in department of pp, my character? i cannot describe it well, but i know i am optimistic and confident. sometimes i prefer to stay alone, reading, listening to music, but i am not lonely, i like to chat with my classmates, almost talk everything ,my favorite pastime is valleyball,playing cards or surf online. through college life,i learn how to balance between study and entertainment. by the way, i was a actor of our amazing drama club. i had a few glorious memory on stage. that is my pride.高校生英语自我介绍及翻译篇15hello.everyone.it is really good to see you here.i am.....,come from china.this is my first time to this beautiful country ,,i am so delighted to have the opportunity to be here with you guys .ijust finished my study in high school ,and i would like to further my study here.but my english is not that good ,i need your help .anyway ,i hope we can enjoy ourselves being together .thank youGeneral IntroductionI am a third year master major in automation at Shanghai Jiao Tong University, P. R. China. With tremendous interest in Industrial Engineering, I am writing to apply for acceptance into your Ph.D. graduate Education backgroundIn 1995, I entered the Nanjing University of ScienceTechnology (NUST) -- widely considered one of the Chinas best engineering schools. During the following undergraduate study, my academic records kept distinguished among the whole department. I was granted First Class Prize every semester,In 1999, I got the privilege to enter the graduate program waived of the admission test.At the period of my graduate study, my overall GPA(3.77/4.0) ranked top 5% in the department. In the second semester, I became teacher assistant that is given to talented and matured students only. This year, I won the Acer Scholarship as the one and only candidate in my department, which is the ultimate accolade for distinguished students endowed by my university. Presently, I ampreparing my graduation thesis and trying for the honor of Excellent Graduation Thesis.Research experience and academic activityWhen a sophomore, I joined the Association of AI Enthusiast and began to narrow down my interest for my future research. With the tool of OpenGL and Matlab, I designed a simulation program for transportation scheduling system. It is now widely used by different research groups in NUST. I assumed and fulfilled a sewage analysisdispose project for Nanjing sewage treatment plant. This was my first practice to convert a laboratory idea to a commercial product.In retrospect, I find myself standing on a solid basis in both theory and experience, which has prepared me for the Ph.D. program. My future research interests include: Network Scheduling Problem, Heuristic Algorithm research (especially in GA and Neural network), Supply chain network research, Hybrid system performance analysis with Petri nets and Data Mining.高校生英语自我介绍及翻译篇16I am Andrea. Perhaps the word average can best describe me. I am of average heigHt, average weight and of average complexion. I have a thin face, double-lid eyes and a pointed nose. My hair is black, short and straight. I have never worn my hair long.I looklike both my mother andmy father, but I have inherited their best parts.lam a teacher, and I like my job. I believe her or his students can sometimes teach a teacher. Actually I have learnt a lot from my own teaching experience and my students. One particularly good thing about being a teacher is that I am learning something new each day and thus making progress each day. This is wonderful. Of course the income is modest, but on the other hand, quite stable. I keep growing all the time. I find great rewards both monetarily and mentally.I have many hobbies: reading books, raising pets, making dresses, etc. I like volleyball very much, but I cant play it very often, because it is a team sport. It is difficult to get enough people to play volleyball with me. Its a shame. I derive great pleasure out of my hobbies.Generally speaking, I am open, honest and easy-going. I hate hypocrisy and injustice. Fairness is very important to me. I try to be fair in everything I do. I have great appreciation for physical and spiritual independence. I am a bit disorganized and impatient sometimes.I dont have many friends, but I do have a few. I have both male and female friends. We do sports together, go shopping together;and we exchange our views and ideas and share happiness and sadness. Of course we help each other if necessary. I always consider myself a lucky person. I am lucky in my family, I am lucky in my career, I am lucky in my friendship, I am lucky in many things. In one word, I am lucky in life. I am really grateful for all these.我叫安德里亚。
标准英语演讲稿格式及范文【导语】演讲又叫讲演或演说，是指在公众场所，以有声语言为主要手段，以体态语言为辅助手段，针对某个具体问题，鲜明、完整地发表自己的见解和主张。
本篇文章是老师为您整理的《标准英语演讲稿格式及范文》，供大家阅读与鉴赏。
英语演讲稿格式1）开始时对听众的称呼语最常用的是 Ladies and gentlemen，也可根据不同情况，选用 Fellow students, Distinguished guests, Mr Chairman, Honorable Judges（评委）等等。
2）提出论题由于演讲的时间限制，必须开门见山，提出论题。
提出论题的方法有各种各样，但最生动，最能引起注意的是用举例法。
比如：你要呼吁大家关心贫穷地区的孩子，你可以用亲眼看到的或者收集到的那些贫穷孩子多么需要帮助的实例开始。
另外，用具体的统计数据也是一个有效的引出论题的方法，比如：你要谈遵守交通规则的话题，你可以从举一系列有关车辆、车祸等的数据开始。
3）论证对提出的论题，不可主观地妄下结论，而要进行客观的论证。
这是演讲中最需要下功夫的部分。
关键是要把道理讲清楚。
常见的论证方法有举例法、因果法、对比法等等，可参见英语议论文的有关章节。
4）结论结论要简明扼要，以给听众留下深刻印象。
5）结尾结尾要简洁，不要拉拉扯扯，说个没完。
特别是不要受汉语影响，说些类似“准备不足，请谅解”，“请批评指正”这样的废话。
最普通的结尾就是：Thank you very much for your attention。
篇一Today I am very happy,Because I can talk aboutwith you.You see I am a lovely girl,yes!I like laughing,I like studying.That`s me-- zhuyingjie from Badong shiyan primary school.I ameight. I am young but I know “we are the masters of nature.”We have only one earth. But now,the environment becomes worse and worse. As you know,there's no enough clean water for people.So many of them lose their lives because ofwater.If we take good care of our earth today,it will be more beautiful tomorrow.My dear friend let us start from the trivialside,To be a good kid keeper.译文：你好,每个人!今天我很高兴,因为我可以和你谈谈。
大学第一节英语课自我介绍_大一新生自我介绍英文大学第一节英语课自我介绍范文篇一 Hello,everyone!I ** 200xx University graduates Social Sports session, performance excellence, sports and basic skills down. University branch secretary for four years as class groups responsible, enterprising, hard working, high moral character, serious and responsible work. Won a scholarship every year, Excellent student title, and received outstanding graduates, outstanding intern, outstanding League Cadres, Party members.In all respects strict demands on themselves, thinking motivated, study hard, work for, simple life. Four years of rigorous practice to make me a good university graduates. Strong self-learning ability, to overcome problems; with solid professional skills and strong theoretical basisCalm; has a strong ability to identify and deal with non-; have strong organizational skills and social adaptability.Certificates: National Basketball two players, referee; national volleyball two referees; National Computer level, Certificate III in English; the National Putonghua 2 B 1 / 5certificates; School Poetry Recitation Contest first prize.Thank you!大学第一节英语课自我介绍范文篇二 Good morning/afternoon： It is really my honor to have this opportunity for a interview. I hope I can make a good performance today.My name is xx. I am 20 years old，born in a little village in Southern Zhejiang.My parents are farmers,and I am the only child. Though not well-to-do，the family always be hopeful. My major is engineering technology. I will graduate in July，20xx. I have some hobbies like listening to music，swimming，and especially seeing western movies.In the passed two years，I have learned some practical skills and gained some major certificates. I paid more attention to learn Engling，and I have passed CET4 in my efforts.I am looking forward to becoming a member of your company . Thankyou!大学第一节英语课自我介绍范文篇三 How do you do ?Welcome to China!My name is ×××，Iˊm××years old， I live in the city of ××，I study very well.I am an active boy. I like sports very much .I am good at swim-ming.Iaiso like riding a bike 2 / 5because my home is far from school,I ride to school every day.I have a brother.Everyone loves us.But they often compare my bro-ther with me.This make s me angry.I donˊt want to be like my broth-er.I only want to be myself.Iˊm kind-hearted.If you need help,please comet to me.Iˊll try my best to give help to you .I hope we can be friends .大学第一节英语课自我介绍范文篇四 Hi, My name is Jay, I'm from the beautiful ancient city of Kaifeng. As you can see, I am a very casual girl, and a lot of people here, like 18-year-old, I love a lot, I love guitar, love to sing love dancing, very fond of English, I am very love to watch "Prison Break", like the actor micheal clever wit.I like making friends, and hope you will be able to and I have become good friends, I think I will, and you get along with.大学第一节英语课自我介绍范文篇五hello.everyone.it is really good to see you here.i am.....,come from china.this is my first time to this beautiful country ,,i am so delighted to have the opportunity to be here with you guys .i just finished my study in high school ,and i would like to further my study here.but my english is not that good ,i need your help .anyway ,i hope we can enjoy ourselves 3 / 5being together .thank youGeneral IntroductionI am a third year master major in automation at Shanghai Jiao Tong University, P. R. China. With tremendous interest in Industrial Engineering, I am writing to apply for acceptance into your Ph.D. graduate program.Education backgroundIn 1995, I entered the Nanjing University of Science & Technology (NUST) -- widely considered one of the China’s best engineering schools. During the following undergraduate study, my academic records kept distinguished among the whole department. I was granted First Class Prize every semester,In 1999, I got the privilege to enter the graduate program waived of the admission test.At the period of my graduate study, my overall GPA(3.77/4.0) ranked top 5% in the department. In the second semester, I became teacher assistant that is given to talented and matured students only. This year, I won the Acer Scholarship as the one and only candidate in my department, which is the ultimate accolade for distinguished students endowed by my university. Presently, I am preparing my graduation thesis and trying for 4 / 5the honor of Excellent Graduation Thesis.Research experience and academic activityWhen a sophomore, I joined the Association of AI Enthusiast and began to narrow down my interest for my future research. With the tool of OpenGL and Matlab, I designed a simulation program for transportation scheduling system. It is now widely used by different research groups in NUST. I assumed and fulfilled a sewage analysis & dispose project for Nanjing sewage treatment plant. This was my first practice to convert a laboratory idea to a commercial product.In retrospect, I find myself standing on a solid basis in both theory and experience, which has prepared me for the Ph.D. program. My future research interests include: Network Scheduling Problem, Heuristic Algorithm research (especially in GA and Neural network), Supply chain network research, Hybrid system performance analysis with Petri nets and Data Mining.5 / 5。
Integrated Design and Process Technology,IDPT-2002Printed in the United States of America,June,2002c2002Society for Desing and Process Science Formal Relationship between Petri Nets and Graph Grammars as Basis for Animation Views in GenGEDRoswitha Bardohl,Claudia Ermel,Julia PadbergInstitute for Software Engineering and Theoretical Computer ScienceTechnical University of Berlin,Germanyrosi,lieske,padberg@cs.tu-berlin.deABSTRACT:Specification techniques like Petri nets al-low for the formal description and analysis of systems. Although tool support exists for many different Petri net classes and tasks,a domain-specific animation of net behav-ior,however,is not yet supported by many Petri net tools. In this contribution,we present a formal approach for the generic specification of several Petri net classes includ-ing animation views.The approach follows the notions of GenGED,a tool for the visual specification of visual lan-guages based on algebraic graph transformation.More-over,we give a proof of the semantical compatibility of Algebraic High-Level Petri nets and their representation as graph grammars in GenGED.The proof is based on the for-mal semantics of Petri net behavior and the construction of graph derivations as pushouts in the category of graphs and graph morphisms.Based on the behavior equivalence,we can define ani-mation views for specific Petri nets in GenGED:the ani-mation view of a system modeled as a Petri net consists of a domain-specific layout and animation rules according to the graph grammar representation of the Petri net.K eywords:Petri nets,visual languages,graph grammars, stepwise animationI.I NTRODUCTIONVisual modeling techniques are of growing interest for an application-oriented presentation of models given by a formal specification.Especially,for non-experts in formal modeling,a layout of the model and its behavior simulation in the application domain would be desirable.Based on the GenGED approach for the generic specification of vi-sual languages(VLs),we define a relationship between the formal model of Petri nets and a so-called animation view by giving a layout for a model as icons in the application domain.The GenGED environment supports the visual specifi-cation of visual environments that are generated from the specification.Concerning editing,the specification of ei-ther syntax-directed[1]or free editing[4]is supported. VLs describing processes,like Automata,Statecharts or Petri nets,usually are suitable for simulating the behav-ior.The behavior is defined by a simulation specification which is executable in a generated VL environment[2]. All environment specifications in GenGED are based on the well-defined concepts of algebraic graph transforma-tion and graphical constraint solving.These concepts have been used as a unifying representation for various Petri net classes in GenGED[3],[9].Many different encodings of Petri nets into graph gram-mars have been proposed in the literature[16].We focus on a very natural encoding of nets into grammars,namely we regard a net as a graph grammar acting on graphs rep-resenting the markings of a net.A Petri net transition is represented as a graph rule consuming the tokens in the pre-domain and generating the tokens in the post-domain of the transition.Places are represented as graph vertices which are preserved by the rule.This is indicated by dashed ar-rows in Fig.1showing an example for the translation of a transition from a Place/Transition net(short P/T net)to a graph rule in the Single-Pushout(SPO)approach to at-tributed graph transformation[11].The left-hand side of the graph rule holds the pre-domain tokens to be consumed and the right-hand side holds the post-domain tokens to be generated.For a specification of P/T nets as graph gram-mars in the Double-Pushout(DPO)approach see[5].(a)Fig.1.(a)A transiton of a P/T net,(b)the corresponding graph rule Obviously,such a representation satisfies the properties of the token game in Petri nets:a rule can be applied to a given marking iff the corresponding transition is enabled, and thefiring of a transition produces the same marking as the SPO construction.In this paper,we adapt the approach of Korff and Ribeiro in[10]and show that the semantics of an Algebraic High-2Level (AHL)net (based on sets of traces)is compatible (i.e.isomorphic)to the operational semantics of the graph gram-mar encoding it within the GenGED framework.The main difference in the encoding of AHL nets as graph grammars between [10]and our approach lies in the representation of markings.In [10],[5],markings are discrete graphs (token nodes labeled by place names).In GenGED,tokens and places are modeled as attributed nodes of different types,connected by edges.The fact of semantic compatibility be-tween Petri nets and their representation as graph grammars is the formal basis for the definition of an animation view of a Petri net in an application-specific layout.The basic idea is to generate animation rules from the graph grammar representation of the net behavior by adapting the visual elements in the rules to an animation-specific layout (ani-mation view ).In our running example of a simple elevator modeled as an AHL net,the animation view shows directly the move-ments of the elevator cabin between the different floors.In order to keep the example simple,the AHL net does not model the control mechanism to call the elevator but only the movements up and down (see Fig.2).In gen-eral,the system states show in which floor the elevator is,and whether it is moving or not.The firing conditions of the transitions up and down control that the elevator does not move out of the range of the possible floors:in Fig.2a house with five floors is modeled because the SPEC-algebrabinds the constant to the value 5and to the value 0.The model requires the al-gebraic datatype specification N at of natural numbers and uses the datatype operations ””and ””for computing the current floor number.The two constants and fix the height of the house the elevator is working in.It is obvious that the constants in our data type specification together with the firing conditions of the transitions restrict the domain of data values for tokens tothe range.The initial mark-ing specifies that in the beginning the elevator must be in the ground floor,in the state not moving (token ”0”on place not moving ).startstop f<MaxFloorup f > MinFloordown f f+1ff-1movingnot movingf f f f=(I A SPEC SPEC = NAT +opns MaxFloor,MinFloor: -> NATN,5,0)Fig.2.A basic elevator as AHL netA conceivable animation view of the AHL net is illus-trated in Fig.3.We show two snapshots of the animation view according to two possible markings of the net in Fig.2.The elevator is illustrated as part of a building showing the actual number of floors.The elevator cabin which is vi-sualized as box with doors is intended to move between thefloors of the building.When the elevator is in the state mov-ing as shown in the left part of Fig.3,the cabin is positioned in the analogous floor and the doors are closed.This snap-shot corresponds to a token ”3”on place moving .When the elevator has stopped (state not moving ),the cabin doors are open.This is shown in the right snapshot of Fig.3,and corresponds to a token ”2”on place not moving .45213452130Fig.3.Animation view snapshotsThe actions that can be performed in the animation view of our model correspond to the transitions in the AHL net.Thus,for example,when the elevator has stopped (state not moving ,it is not possible to perform the actions up or down because only the transition start is enabled in the corre-sponding net.The paper is structured as follows:In the next section we briefly review the GenGED concepts which are illustrated by the specification of the AHL net language.In Section III we show the semantic equivalence of AHL nets and their graph grammar representation as formal foundation for the animation view specification.On this formal basis,in Sec-tion IV,a sample animation view specification for our ele-vator model is given.II.D EFININGTHEP ETRI N ET L ANGUAGEWITHING EN GEDThe GenGED approach and environment was developed in order to support the visual specification of visual lan-guages (VLs)in an easy way,and to generate visual en-vironments.In addition to this overall requirement it was desired to find a suitable formalism allowing for easy ex-tensions of the application:the GenGED approach is based on algebraic graph transformation and graphical constraint solving techniques.A concrete AHL net like that in Fig.2,for example,is represented by an attributed graph (an al-gebra)to a given type graph (a signature).In both the type graph and the instance graphs (also called visual sentences),we distinguish the abstract syntax (the symbols and links)and the concrete syntax (the layout).The abstract syntax is represented by an attributed graph.The vertices represent visual symbols such as a place or a transition of a Petri net,and the edges describe the logically meaningful spatial rela-tions between symbols,e.g.that a token belongs to a place.Vertex attributes define data values,like names for places3 or transitions.The layout of symbols and links is given byfurther vertex attributes denoting the shape,position,color,etc.,and graphical constraints which have to be satisfied byeach visual sentence.Although we concentrate on the ab-stract syntax in the following sections,we briefly sketch the concrete syntax also.Similar to formal textual languages,a visual language is specified by an alphabet for symbol and link types(the type graph),and a grammar consisting of a start sentence and a set of syntax rules.A visual language VL is then the set of all visual sentences that can be derived by applying syntax rules[1].These original concepts of GenGED for syntax-directed editing have been extended for free editing(pars-ing)[4]and simulation[2].This means,visual grammars are interpreted differently,however,this topic is beyond the scope of this paper.Instead we concentrate on a brief intro-duction of the concepts,namely that of an alphabet and a grammar,illustrating the power of VL specifications using GenGED.An alphabet is given by a set of symbol and link types of a specific VL as well as a graphical constraint satisfaction problem.The alphabet for the AHL net language is shown in Fig.4.Fig.4.Visual alphabet for AHL netsDue to the abstract syntax level,there are symbols as Place,Trans(Transition),etc.in Fig.4which are partly at-tributed by datatypes like PN(Place Name)or TV(Token Value)of type String.These abstract syntax items are linked via directed edges.Note that we distinguish arcs running from places to transitions(type PreArc)and from transitions to places(type PostArc).The concrete syntax level is de-scribed by further vertex attributes of type Graphic and by graphical constraints specifying the intended layout.We use dotted arrows at the concrete syntax level in order to indicate the graphical constraints.A VL grammar is based on the specific alphabet and the powerful meansof graphtransformation:grammar rules arenot restricted to be context-free but context-sensitive.The left-hand side(LHS)of a rule does not comprise a single non-terminal symbol but a complete sentence,as well as the right-hand side(RHS).A rule expresses either the in-sertion or deletion(or both)of symbols.The rule insPre(ipt) depicted in Fig.5defines the operations for inserting an arc between a place and a transition.The newly created arc is inserted together with the arc inscription defined by the rule parameter ipt.R LFig.5.Syntax rule from the AHL net grammarA rule can be applied to a given sentence by mapping the abstract syntax items of the rule’s LHS to items of the sentence.Then,the sentence is transformed according to the rule by inserting or deleting items to/from the sentence. Please note that we omit the complete specification of the AHL net language for the sake of space;the reader is referred to[3]for more details.Instead we discuss the se-mantical compatibility of Petri nets and their representation in GenGED based on the alphabet shown in Fig.4.III.S EMANTICAL C OMPATIBILITY OF P ETRI N ETS AND THEIR R EPRESENTATION IN G EN GED Before we prove the semantical compatibility of the Petri net semantics and the graph grammar semantics of an AHL net representation within GenGED,we briefly review the formal definitions of AHL nets and attributed graph gram-mars.A.AHL NetsWe review the basic definition of AHL nets and their be-havior as given in[13].Further information about similar high-level Petri net approaches can be found for instance in [17],[14],[8].Note that the pre and post-domain of a tran-sition is given by a multiset of pairs of terms and places, i.e.as elements of a free commutative monoid.Definition III-A.1(AHL Net)An Algebraic High-Level net(AHL net)consists of an algebraic specificationwith equations and additional variables over the signature[7],sets and of places and transitions respectively,pre-and post-domain functionsassigning to each transition the pre-and post-domains and (see below)respectively,afiring condition func-tion assigning to each transition afinite set of equations over the signature(S,OP)with variables and an-algebra[7].A marking is a multiset of pairs of data elements of distributed on places:.is the set of terms with variables over the signature[7],being the cartesian product and the free commutative monoid over a set .This means that(and similar)is of4the form with.Thus,the multisetis the pre-domain of with arc-inscription for the arc from to if the elements of are distinct (unary case)and arc-inscription for(multi case).Definition III-A.2(Behavior of AHL Nets)Enabling and firing of transitions is defined as follows:let be the set of local variables occurring in and .An assignment is called consistent for if the equations are satisfied in under.A transition is enabled under a consistent assignment and a marking,ifThe marking–analogously–is defined for byis the extended evalu-ation of terms under assignment[7].The successor marking is defined in the case of be-ing enabled byand gives raise to afiring step.Definition III-A.3(Semantics of AHL Nets)The set of all steps of an AHL net is denoted by .A sequence is called firing sequence iff or andfor all.The semantics of an AHL net is defined by the set of allfiring sequences of.B.Attributed Graph TransformationIn the theory of algebraic graph transformation,a graph is given by disjoint sets indicating vertices and edges from a source vertex to a target vertex.Vertices may be addi-tionally enhanced by attributes that are used to store data together with the vertices1.Such attributes are elements of an attribute algebra.Definition III-B.1(Attributed Graph)An attributed graphconsists of a set of vertices,a set of edges,an algebra,where is the category of all-algebras and-homomorphisms,source and target func-tions,and an attribution function,connecting vertices with attributes (data elements of the algebra).Definition III-B.2(Attributed Graph Morphism)A(par-tial)attributed graph morphism between the attributed graphs and is a tupleIn general,attributes for edges are possible,too.In the GenGED ap-proach,however,we only need vertex attributes.consisting of partial functions andsuch that andfor all and all ,and a homomorphism such that for all.Attributed graphs and graph morphisms form the cocom-plete category A GG in the Single-Pushout approach to al-gebraic graph transformation([11],[12],[6]).In general,graph transformation defines a rule-based ma-nipulation of graphs.(For an overview of the main ap-proaches see[15].)Graph rules can be used to capture the dynamical aspects of systems.The resulting notion of graph grammars(consisting of a start graph and a set of graph rules)generalizes Chomsky grammars from strings to graphs.The start graph represents the initial state of the system,whereas the set of rules describes the possible state changes that can occur in the system.A rule comprises two graphs:a left-hand side and a right-hand side,and a partial graph morphism from to.Definition III-B.3(Attributed Graph Grammar)An attributed graph rule is an attributed graph morphism such that and are injective and is the identity on a quotient term algebra with variables in.An attributed graph grammar consists of an attributed graph(the start graph)and a set of attributed rules(or productions).The application of a rule to a graph(also called derivation)requires a total morphism from to,called match.We here restrict the match to injective morphisms only.Thus we avoid the problem that two distinct nodes of the LHS are identified by the match,and the rule is applied to a graph modelling less tokens on the pre-domain places than the number expected for enabling the corresponding transition.Note that this problem does not occur in the DPO approach[5]because of the gluing condition which requires that the nodes of the LHS which shall be deleted are not merged by the match.Formally,a derivation step from to with rule and match is defined by a pushout construction(see[11])and is denoted by.Definition III-B.4(Derivation Step)Letbe an attributed graph grammar.A derivation step of an attributed graph where with ruleat match is a pushout of and in A GG where .5dL R dmd m dr (PO)HGA derivation step according to the pushout construction consists of three steps transforming the graph to graph .First,the vertices in which do not have an image via in are deleted in .Thereafter,the vertices in without origin in are created and appended to the graph.(Vertices in which are mapped to by are preseved by the rule.)As a last step,all edges which are not defined any more are deleted from the graph.Sometimes the application of a rule shall be constrainedw.r.t.the attribution,as for example(conditional rule ).In this case we specify the attribution algebra of the rule equationally,i.e.the required equations are syntacti-cally added to the rule implying that the terms annotating the rule shall be interpreted in the corresponding quotient term algebra.Definition III-B.5(AGG Semantics)The set of all deriva-tion steps inis denoted by .A se-quenceis called a sequential deriva-tion of ,also denoted by if either or and for all .The semanticsis the set of all sequen-tial derivations of.C.Translating AHL Nets to Graph GrammarsThe translation of AHL nets into graph grammars gen-eralizes that of P/T nets into graph grammars as sketchedin the introduction.The marking of a net is transformed to a graph consisting of bundles of vertices of type Token (the tokens).Each Token vertex is connected to a vertex of type Place representing its place and attributed by a data value from the net’s algebra.Thus,each token of the net can be expressed in the graph as an edge from an attributed vertex of type Token to a vertex of type Place attributed by its name.The initial marking of an AHL net is translated to thestart graph of a graph grammar(Def.III-C.1),whereas the transitions together with their pre and post-domains are translated to rules (Def.III-C.5).Definition III-C.1(Translation of Markings)Letbe a marking of the AHL net.The translation of is given by the attributed graphwith.The multisethere is givenby the set,where multiple occurrences of the same element in arenumbered by in .,with andwith ,withThis means that places are attributed by their names and tokens by their data values.The backward translation of to a marking of is de-fined as follows:Fact III-C.2(Compatibility of )Letbe a marking of an AHL net ,and bethe translation ofto and the backward trans-lation as defined in Def.III-C.1.Then,.Proof III-C.3(Compatibility of)withdefined as in Def.III-C.1Example III-C.4(Marking of Elevator Net)Fig.6showsthe AHL net modeling our basic elevator marked by the ini-tial marking and the translation to an attributed graph (the start graph of the corresponding ).startstopf<MaxFloorupf > MinFloordown not movingf f f fff+1ff−1movingSPEC , AAHL Net N marked with mFig.6.Translation of the elevator net’s initial marking to an attributedgraphThe only edge in the translated graph formally is given by6 We now define the translation of the transitions in torules encorporating thefiring behavior:the left-handside of each rule contains the pre-domain,the right-handside the post-domain.Definition III-C.5(AHL Net Translation)Letbe an AHL net.Then the translated attributed graph grammar is defined aswhere the start graphis the translated initial marking of the net accord-ing to Def.III-C.1,and the set of behavior rulescorresponds to thefiring be-havior of the transitions withbeing the environment of transition. In each behavior rule,the left-hand side corresponds to the pre-domain,and the right-hand side to the post-domain.Thus,in the following definition of the graph,the set is defined by for and byfor,wherecorresponds to andcorresponds to.Each behavior rule side is an attributed graph defined as follows:with.,withandwithThe rule morphismis the identity on the place vertices(the ver-tices are not in the domain of)and the iden-tity on the terms in the quotient term-algebra.By the construction of it is obvious thatis a well-defined attributed graph and that all rules inare attributed rules.Thus,is an attributed graph grammar.Example III-C.6(AGG for Elevator Net)ex:TransNet Let be our Elevator Net shown in Fig.2.Let AGG be the translated graph grammar accord-ing to Def.III-C.5.The start graph is shown in Fig.6, whereas Fig.7shows the rules in corresponding to the transitions.f<MaxFloorLL downdownupL up Rdownf>MinFloorupL stopstartstopFig.7.Translation of the elevator net’s transitions to rulesThe following theorem states the compatibility betweenthe semantics of an AHL net and the semantics of its trans-lation into an AGG.Theorem III-C.7(Semantical Compatibility)The seman-tics of an AHL net and the semantics of thetranslation are compatible,denoted by.The semantics of a net is given in terms of sets offiringsequences(firing steps),and the graph grammar semanticsas sets of derivation sequences.Proof III-C.8(Semantical Compatibility)We We have to show that1.the initial marking of is translated to the startgraph of the graph grammar,2.for eachfiring stepthere is a derivation step withs.t.the resulting marking corresponds to graph ofthe pushout,i.e.,3.eachfiring sequence corresponds toa derivation sequence.This means,for all pairss.t.,we have in the correspondingpushout diagrams.ad1.Holds by the definition of.ad2.Let be afiring stepin.Then is constructed as follows:Rule:as defined in Def.III-C.5Match:with the vertices being matched by.7 The match satisfies the graph morphism prop-erties:with8Fig.8.Visual syntax of the elevator net and its animation viewthe animation view (view transformation rules).The gener-ation of the animation view in Example IV-A.1is described in Section IV-B.The behavior of the system in the animation view then is given by a set of animation rules on the VL sentences of the animation view.The abstract syntax of the animation rules equals the abstract syntax of the behavior rules for the Petri net (see Fig.7for the abstract behavior grammar of the elevator net).We call the grammar containing the animation rules,the animation grammar .Example IV-A.2(Animation Grammar)Fig.9shows the animation grammar for our elevatormodel.Each an-imationrule corresponds to the behavior rule of the same name from the behavior grammar in Fig.7and thus to a transition in the elevator net.Fig.9.Animation grammar for the elevator modelB.Generating Animation ViewsThe aim,of course,is to construct the animation gram-mar in a way that the animation is consistent to the behavior specification.Therefore,we now define the generation of an animation view by grammar rules that transform all pos-sible states of the system model into an appropriate state of the animation view (view transformation rules).On the basis of these view transformation rules it is possible to en-force coherence between the behavior grammar of the orig-inal visual process model (the Petri net)and the animation grammar of the animation view.The view transformation rules allow to transform the VL sentences from the old lay-out to the new layout and the behavior rules into the anima-tion rules.In general,each of the view transformation rules trans-forms a subset of all possible Petri net markings to the an-imation view by combining elements of the abstract syntax with new concrete syntax elements (i.e.by giving them a different layout).After applying the view transformation rules,the VL sentence denoting the initially marked Petri net is transformed into a corresponding animation view.Formally,view transformation rules operate on the union of both the visual syntax of the Petri net and the visual syn-tax of its animation view.Although the abstract syntax is the same,the concrete syntax (the layout)differs.In the following example,therefore,graphics from both concrete syntax definitions(net layout and animation view layout)are shown in the same rules.ExampleIV-B.1(View Transformation Rules)Fig.10shows the view transformation rules neededfor the gen-eration of the animation view from theinitially marked el-evator net (both depicted in Fig.8).We define one view transformation rule for the marking of each place.In the view transformation rules in Fig.10,the abstract syntax remains,but the symbols are re-linked to the new anima-tion view graphics as they are introduced in the right-hand sides of the rules.Fig.10.View transformation rules for the elevator modelThe behavior of a Petri net now can be transferred to the animation view by applying the view transformation rules to the LHSs and RHSs of the behavior rules.Example IV-B.2(Generating Animation Rules)Fig.11illustrates the derivation of an animation rule by applying rules from the view transformation grammar in Fig.10to the behavior rule start from Fig.7.A stepwise animation of the system can be performed by applying the animation rules in the animation view of the system model.An extension of the approach towards a more sophisticated animation would be the presentation of system behavior not as discrete steps but as a movie (”smooth”animation),i.e.showing a series of intermedi-ate states for the firing of one transition.With this aim in mind,an animation framework as proposed in [19]could be combined with the GenGED environment.9Fig.11.Derivation of an animation rule with view transformation rulesV.C ONCLUSIONIn this paper,we have given a formal approach for the representation of Petri nets in GenGED in terms of at-tributed graph grammars.In this encoding,graphs repre-sent the markings of a net,and for each transition,a graphrule models thefiring behavior.We show that the seman-tics of an AHL net and the semantics of its representation in GenGED(the behavior specification)are compatible.Onthis formal basis it becomes possible to define animationviews for Petri nets in an application-specific layout wherethe animation is formally derived from(and thus consistentto)the behavior specification.In our running example we have specified and animateda simple elevator model.This is formally specified usingAHL nets and animated in a freely chosen layout.It remains to develop behavior and animation views forother visual modeling languages than Petri nets.Hence,aformal theory allowing to handle behavior and animation ofvarious VL models in a generic way based on the GenGED approach is the overall aim of our work.On the practical side,the GenGED tool environment hasto be extended in order to be able to manage the combina-tion of different VLs with the same abstract but different concrete syntax.Based on these extensions,the GenGEDtool environment will be able to handle different views ofa VL model,including support for the visualization of be-havior in terms of the formal model itself(e.g.token gamesimulation)and animation in a domain-specific layout as discussed in this paper.Acknowledgements This work has been partially sup-ported by the DFG-Researcher Group P ETRI N ET T ECH-NOLOGY and by the German-Brazilian project G RAPHIT. 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