chapter4软件工程双语
软件工程(外文翻译文献)
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。
软件工程双语答案
软件工程双语答案1. 什么是软件工程？ (What is Software Engineering?)软件工程是一门研究如何以系统化、规范化和可预测的方式开发和维护软件的学科。
它涉及到对软件的需求分析、设计、编码、测试、部署和维护等方面的活动。
软件工程旨在通过工程原理和方法来提高软件开发的质量和效率。
2. 为什么软件工程如此重要？ (Why is Software Engineering Important?)软件在现代社会中已经无处不在，它们贯穿于我们的日常生活和工作中。
由于软件的重要性，软件工程变得至关重要。
软件工程的正确实践确保软件在开发和维护过程中的高质量和可靠性。
软件工程还帮助开发团队更好地理解需求、规划项目、管理进度和标准化开发过程，以确保软件项目的成功完成。
3. 软件工程的核心原则有哪些？ (What are the Core Principles of Software Engineering?)下面是软件工程的核心原则：•可行性研究 (Feasibility Study): 在项目开始之前，应该进行可行性研究，以评估项目的可行性和风险。
•需求规格说明 (Requirement Specification): 需要清晰、详尽的需求规格说明，以便开发团队准确理解客户的需求。
•设计 (Design): 设计阶段是根据需求规格说明创建软件架构和用户界面的过程。
•编码 (Coding): 编码是将设计转化为实际可执行代码的过程。
在编码过程中，应遵循编码标准和最佳实践。
•测试 (Testing): 测试是评估软件质量和是否满足需求的过程。
测试应该覆盖所有的功能和边界情况。
•部署与维护 (Deployment and Maintenance): 软件的部署和维护需要进行系统化的过程，以确保软件可以稳定运行，并及时修复和更新软件。
4. 软件工程中常用的开发模型有哪些？ (What are the Common Development Models in Software Engineering?)软件工程中常用的开发模型有以下几种：•瀑布模型 (Waterfall Model): 瀑布模型是一种顺序开发模型，其中每个阶段依序进行，前一阶段的输出作为下一阶段的输入。
软件工程（双语）习提纲
Chapter 1 An Introduction to Software Engineering*What is software?-Computer programs and associated documentation and Data-Two fundamental types of software product: generic products and customized products*What is software engineering?-Software engineering is an engineering discipline which is concerned with all aspects of software production*What is the difference between software engineering and computer science?-Computer science is concerned with theory and fundamentals;-software engineering is concerned with the practicalities of developing and delivering useful software*What is a software process?-A set of activities whose goal is the development or evolution of software-Generic activities in all software processes are:•Specification 、Development 、V alidation 、EvolutionChapter 4 Software Process*Software process-Software processes are the activities involved in producing and evolving a software system.-A structured set of activities required to develop a software system: specification; design and implementation; validation; evolution.-General process activities are specification, design and implementation, validation and evolution.*Software process models-Software process models are abstract representations of these processes.-Generic process models describe the organisation of software processes. Examples include the waterfall model, evolutionary development andcomponent-based software engineering.-waterfall model is only appropriate when the requirements are well-understood and changes-The waterfall model is mostly used for large systems engineering projects where a system is developed at several sites-There are two fundamental types of evolutionary development: exploratory development and throw-away prototyping-Exploratory development should start with well-understood requirements and add new features as proposed by the customer-Throw-away prototyping should start with poorly understood requirements to clarify what is really needed.- Evolutionary development is mostly used for small or medium-size interactive systems and short-lifetime systems*Iterative process models describe the software process as a cycle of activitiesChapter 5 Project management*Primary project management activities:-Proposal writing.-Project planning and scheduling.-Project costing.-Project monitoring and reviews.-Personnel selection and evaluation.-Report writing and presentations.*Project planning-Milestones are the end-point of a process activity.-Deliverables are project results delivered to customers.*Project scheduling-Organize tasks concurrently to make optimal use of workforce.-Minimize task dependencies to avoid delays caused by one task waiting for another to complete.-Graphical notations used to illustrate the project schedule: bar charts and activity networks-Activity charts show task dependencies and the critical path.-Bar charts show schedule against calendar time.Task durations and dependenciesActivity networkActivity bar chart (Gantt chart)Staff allocation vs. time chart chart*Risk management-Three related categories of risk: project risks, product risks, business risks -Project risks affect schedule or resources;-Product risks affect the quality or performance of the software beingdeveloped;-Business risks affect the organisation developing or procuring the software -The process of risk management involves several stages: Risk identification, Risk analysis, Risk planning, Risk monitoring.-Risk identification: Identify project, product and business risks;-Risk analysis: Assess the likelihood and consequences of these risks;-Risk planning: Draw up plans to avoid or minimise the effects of the risk;-Risk monitoring: Monitor the risks throughout the project;The risk management processChapter 6 Software Requirements*Types of requirement:-Functional and non-functional requirements-User requirements and system requirements*Functional and non-functional requirements-Functional requirements•Statements of services the system should provide, how the system should react to particular inputs and how the system should behave inparticular situations.-Non-functional requirements•Constraints on the services or functions offered by the system such as timing constraints, constraints on the development process, standards,etc.-The types of non-functional requirement are: product requirements,organisational requirements, external requirements.-Functional requirements set out services the system should provide.-Non-functional requirements constrain the system being developed or thedevelopment process.*In principle, requirements should be both complete and consistent.-Complete•They should include descriptions of all facilities required.-Consistent•There should be no conflicts or contradictions in the descriptions of the system facilities.Chapter 7 Requirements Engineering Processes*The requirements engineering process includes- Feasibility study, requirements elicitation and analysis, requirements specification and requirements management.Chapter 8 System Model*Different models present the system from different perspectives•External perspective showing the system’s context or environment;•Behavioural perspective showing the behaviour of the system;•Structural perspective showing the system or data architecture.*Two types of behavioural model are:•Data flow models that show how data is processed as it moves through the system;•State machine models that show the systems response to events.Chapter 11 Architectural Design*Architecture and system characteristics-performance•Localise critical operations and minimise communications. Use large rather than fine-grain components.-security•Use a layered architecture with critical assets in the inner layers.-safety•Localise safety-critical features in a small number of sub-systems.-Availability•Include redundant components and mechanisms for fault tolerance.-Maintainability•Use fine-grain, replaceable components, avoid data shareChapter 12 Distributed Systems Architectures*Distributed systems architectures-Client-server architectures•Distributed services which are called on by clients. Servers that provide services are treated differently from clients that use services.-Distributed object architectures•No distinction between clients and servers. Any object on the system may provide and use services from other objects.*Middleware is usually off-the-shelf rather than specially written software.*Layered application architecture-Presentation layer•Concerned with presenting the results of a computation to system users and with collecting user inputs.-Application processing layer•Concerned with providing application specific functionality e.g., in a banking system, banking functions such as open account, close account,etc.-Data management layer•Concerned with managing the system databases.*Thin and fat clients-Thin-client model•In a thin-client model, all of the application processing and data management is carried out on the server. The client is simplyresponsible for running the presentation software.-Fat-client model•In this model, the server is only responsible for data management. The software on the client implements the application logic and theinteractions with the system user.* Three-tier architecturesA 3-tier C/S architecture*P2P architectural models-Peer to peer architectures are decentralised architectures where there is no distinction between clients and servers.-The logical network architecture• Decentralised architectures; • Semi-centralised architectures.Decentralised p2p architectureSemi-centralised p2p architectureChapter 13 Application architectures*Important classes of application are data processing systems, transaction processing systems, event processing systems and language processing system.*Data processing systems operate in batch mode and have an input-process-output structure.Chapter 14 Object-oriented Design*Objects and object classes-Objects are entities in a software system which represent instances of real-world and system entities.-Objects are members of classes that define attribute types and operations.-Object classes are templates for objects. They may be used to create objects.-Object classes may inherit attributes and services from other object classes.*Use-case models are used to represent each interaction with the system.Chapter 16 User interface design*Human factors in interface design-Limited short-term memory•People can instantaneously remember about 7 items of information. If you present more than this, they are more liable to make mistakes.-People make mistakes•When people make mistakes and systems go wrong, inappropriate alarms and messages can increase stress and hence the likelihood ofmore mistakes.-People are different•People have a wide range of physical capabilities. Designers should not just design for their own capabilities.-People have different interaction preferences•Some like pictures, some like text.*User interface design principles*MVC approaches (Information presentation,pp.370)Figure: the MVC model of user interaction* How to design UI (Information presentation, pp. 375)Figure **.1 An input text box used by a nurseFigure **.2 system and user-oriented error messages*The UI design process-The 3 core activities in this process are:• User analysis. Understand what the users will do with the system;• System prototyping. Develop a series of prototypes for experiment;• Interface evaluation. Experiment with these prototypes with users.*Some evaluation of a user interface design should be carried out to assess its suitability.Attribute DescriptionLearnability How long does it take a new user to become producthe system?Speed of operation How well does the system response match the usepractice?Robustness How tolerant is the system of user error?Recoverability How good is the system at recovering from user erroAdaptability How closely is the system tied to a single model of w。
Sofetware Engineering-CHAP-4(软件工程第四章)
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A good design should capture all the functionalities of the system correctly. It should be easily understandable. It should be efficient. It should be easily amenable to change.
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Different modules required to implement the design solution. Control relationship among the identified modules. Interface among different modules. Data structures of the individual modules. Algorithms required to implement the individual modules.
Importance of Design
Design provides the basic framework that guides how the program codes are to be written and how personnel are to be assigned to tasks. Design errors outweigh coding errors. They take more time to detect and correct, and are therefore costlier, than coding. The following makes a comparison between design and coding errors based on a study of 220 errors. Design provides a basis for monitoring the progress and rewarding the developers.
软件工程导论(双语)pp04v2
Evolutionary development
Exploratory development
• Objective is to work with customers and to evolve a final system from an initial outline specification.rstood requirements and add new features as proposed by the customer.
The software process
A structured set of activities required to develop a software system
• Specification; • Design; • Validation; • Evolution.
A software process model is an abstract representation of a process. It presents a description of a process from some particular perspective.
receive the most testing.
Extreme programming
An approach to development based on the development and delivery of very small increments of functionality.
prototyping) may be required.
Applicability
• For small or medium-size interactive systems; • For parts of large systems (e.g. the user
软件工程双语 讲义 大纲模式
《软件工程（双语）》参考教材：《Software engineering》8th Edition Ian Sommervile，Pearson Education, 机械工业出版社，2006参考书目:1、Software Engineering Theory and Practice(Second Edition影印版), Shari Lawrence Pfleeger，Pearson Education, 20012、《软件工程》第四版张海藩清华大学出版社，20073、软件工程，王忠群主编中国科学技术大学出版社 2009-11-14、Software engineering : a practitioner's approach / Roger S. Pressman. 6th ed. Pressman, Roger S. China Machine Press, 2008说明:斜体部分是可选讲授内容, 带星号的习题为可选。
Chapter 1(1) Introduction●Getting started with software engineering1.1Objectives1.To introduce software engineering and to explain its importance2.To set out the answers to key questions about software engineering3.To introduce ethical and professional issues and to explain why they are of concern tosoftware engineers1.2Topics covered1.FAQs about software engineering2.Professional and ethical responsibility1.3Importance of Software engineering●The economies of ALL developed nations are dependent on software.●More and more systems are software controlled●Expenditure on software represents a significant fraction of GNP (gross National product) inall developed countries.( GNP与GDP的关系是：GNP等于GDP加上本国投在国外的资本和劳务的收入再减去外国投在本国的资本和劳务的收入。
chaer软件工程双语
Explain how and why requirements reviews should be done to ensure quality
Requirements elicitation is an especially critical part of the process. We must use a variety of techniques to determine what the users and customers really want.It is only by discussing the requirements with everyone who has a stake in the system, coalescing(接合) these different views into a coherent(粘在一起的, 一致的, 连贯的) set of requirements and reviewing these documents with these stakeholders that we all come to an agreement about what the requirement are.
The goal of the requirements phase is to understand the customer’s problem and needs
During the specification phase, we will decide which requirements will be fulfilled(履行) by our software system;
Chapter 4 (SE) 软件工程 课件
Use Case Model
Application Domain Objects
Subsystems
Solution Domain Objects
Software Lifecycle Activities ...and their models
Requirements Elicitation
Analysis
Subsystems
Software Lifecycle Activities ...and their models
Requirements Elicitation
Analysis
System Design
Detailed Design
Implementation
Testing
Expressed in Structured Realized by terms of by
• Nonfunctional requirements
• Aspects not directly related to functional behavior.
“The response time must be less than 1 second”
• Constraints
• Imposed by the client or the environment • “The implementation language must be Java “ • Called “Pseudo requirements” in the text book.
Analysis
System Design
Detailed Design
Implementation
Testing
软件工程双语教学大纲
软件工程》（双语）教学大纲 课程编号：06301525 课程性质： 必修 课程名称：软件工程概论 学时 / 学分： 48/2.5 英文名称：Software Engineering 考核方式： -pT 、“、-IV. 《Software Engineering — Practitioner '选用教材： Approach 》 Fifth Edition, R.S.Pressman,Mc 大纲执笔人： 顾春华 Graw Hill ， 清华大学出版社影印先修课程：高级语言程序设计、数据库原理大纲审核人： 适用专业： 计算机科学与技术一、教学基本目标软件工程》是计算机科学与技术专业本科生的一门的专业基础课，旨在使学生掌握软件工程的基本概念、 原理和方法， 从软件开发技术、 软件工程管理和软件工程环境等几个方面了解如何将系统的、 规范化的和可以度量的工程方法运用于软件开发和维护中。
要求学生通过本门课的学习，掌握结构化方法、面向对象方法等软件开发技术，初步了解软件复 用的概念及基于构件的开发方法，同时对软件工程管理和环境等内容有一个总体的了解。
二、教学基本内容 第一章 绪论（ Introduction ） 本章主要介绍软件的基本概念、软件危机、软件工程学的范畴、传统软件工程和面向对象软 件工程以及软件工程的应用。
重点掌握：学习软件工程的意义， （Software Lifecycle and Software Development Model ） 介绍了传统的软件开发模型 （瀑布模型、 快速原型模型） 、软 、面向对象过程模型（构件集成模型） 、基于形式化方法的软 重点掌握：各种软件开发模型的内容，不同开发模型的特点比较。
第三章 软件需求分析 （Software Requirement Analysis ） 需求分析是软件生存周期中的一个重要阶段，本章在介绍了软件需求分析的任务、步骤后， 分别按结构化和面向对象两类方法，给出了需求分析模型和它们的描述工具，并结合实例进一步 阐述了结构化分析和面向对象分析的过程。
软件工程(双语)4.4
打印文件
计算机
打印服务器
打印机
打印文件
[打印机就绪] 打印文件
[打印机忙] 保存文件
打印队列
协作图（Collaboration Diagram）
计算机
[打印机忙] 2.2：保存文件
打印队列
1：打印文件 打印服务器
[打印机就绪] 2.1：打印文件
打印机
活动图Activity Diagram
顾客 购买处理 支付货款 收取商品
4. 动态建模
消息（Message） 状态图（State Diagram） 时序图（Sequence Diagram） 协作图（Collaboration Diagram） 活动图（Activity Diagram）
消息
同步消息 异步消息 简单消息
状态图State Diagram
到达 向底楼移动
在底楼
上楼
向上移动
到达
上楼
向下移动
到达 下楼
空闲
超时
状态图之间发送消息
遥控器 关
On()
开 Off()
play()
stop()
On() Off() play()
stop()
CD机 关
On() Off()
开/停止
play() stop()
开/播放
Off()/stop()
时序图（Sequence Diagram）
销售部门
处理销售 库存处理 发送商品来自接通电源打开信号
加热
显示灯亮 水未开
水开了 断电
水壶