外文翻译--《软件工程-实践者的研究方法》

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。

软工学习资料推荐软件工程（Software Engineering）是一门研究和应用如何以系统化和规范化的方法去构建、运行、维护和管理软件的学科。

对于软件工程学习者来说，掌握优质的学习资料是非常重要的，它们可以帮助我们深入了解软件工程的理论和实践，提升我们的编程能力和项目管理技巧。

本文将向广大软工学习者推荐一些值得阅读的软工学习资料。

一、软件工程导论1. 《软件工程导论》（Introduction to Software Engineering）- Ian Sommerville这本书是软件工程学习的经典教材，已经成为了许多大学软工专业的教材之一。

作者通过清晰简洁的语言，详细介绍了软件工程的各个方面，包括软件开发过程、需求分析、软件设计、软件测试等。

它不仅适合软件工程专业的学生，也适合其他对软工感兴趣的读者。

2. 《软件工程：实践者的研究方法》（Software Engineering: A Practitioner's Approach）- Roger S. PressmanPressman的这本书是软件工程领域的经典著作之一，对软件开发的整个过程进行了深入的介绍和剖析。

书中包含丰富的案例和实践经验，让读者能够更好地理解软件工程中的实际问题和解决方法。

二、软件需求工程1. 《软件需求工程》（Software Requirements Engineering）- Karl Wiegers、Joy Beatty这本书主要介绍了软件需求工程的理论和实践。

作者通过大量的示例和案例，详细讲解了如何正确地进行需求分析和需求管理，以及如何定义和验证软件需求。

对于从事软件需求工程的工程师和项目经理而言，这本书是一本不可或缺的好资料。

2. 《需求工程：基础》（Requirements Engineering: Fundamentals）- Klaus Pohl、Chris Rupp本书系统地介绍了需求工程的基本概念和方法，帮助读者全面理解需求工程的整个过程。

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

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

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

读书笔记－－软件⼯程实践者的研究⽅法（⼀）软件⼯程实践者的研究⽅法Software Engineer-Apractitioner’s Approach Fourth Edition第⼆部分软件项⽬的管理第三章项⽬管理的概念作者提出有效的项⽬管理集中于3个P：⼈员（people）,问题(problem),过程(process)。

⼈员：项⽬参与者：包括：领导，项⽬经理，开发⼈员，客户（提出需求的⼈），最终⽤户（使⽤软件者）问题：作者提出软件项⽬管理的第⼀个活动是软件范围的确定。

即以下⼏个问题：背景：软件适应什么系统，产品的背景，有什么限制。

⽬标：软件要产⽣什么样的数据来作为输出。

需要什么输⼊。

功能和性能：软件有哪些功能，需要满⾜什么样的特殊性能。

作者提出⾯对问题“分⽽治之”的策略。

细化，提供更多细节。

过程：过程中如何选择⼀个合适的软件过程模型。

过程采⽤的软将⼯程模型主要有：线性顺序模型，原型模型，RAD模型，增量模型，螺旋模型，构件组装模型，并发开发模型等。

过程需要分解成具体的⼯作任务：如在与⽤户联系的时候，可能需要下列⼯作任务来完成：1.复审⽤户要求2.安排与⽤户讨论的会议3.研究如何定义解决⽅案和⽅法4.为正式的会议准备⼀份“⼯作⽂档”和议程。

5.召开会议6.共同制定需求规格说明书，该说明书能反映软件的数据，功能和⾏为特性。

7.复议每⼀份规格说明书，确认其正确性，⼀致性，和⽆⼆义性。

8.将所有的⼩规格说明书组装起来形成⼀份范围⽂档9.复审范围⽂档。

10.根据需求修改范围⽂档。

For personal use only in study and research; not for commercial use软件工程复习总结第1章软件工程介绍1．软件的定义软件是包括程序、数据及其相关文档的完整集合。

其中，程序是按照事先设计的功能和性能要求执行的指令序列；数据是使程序能正常操作信息的数据结构；文档是与程序开发、维护和使用有关的图文材料。

For personal use only in study and research; not for commercial use软件的定义：1、指令的集合，通过执行这些指令可以满足预期的特征、功能和性能需求2、数据结构，它使得程序可以充分利用信息3描述程序操作和使用的文档2．软件的特征a) 软件是设计开发的，而不是传统意义上的生产制造的b) 软件不会磨损c) 虽然整个工业向着基于构件的构造模式发展，然而大多数软件仍是根据实际的顾客需求定制的3．软件与硬件的区别a) 软件是一种逻辑实体，而不是具体的物理实体b) 软件的生产与硬件不同，软件开发过程中没有明显的制造过程c) 软件在运行、使用期间没有磨损、老化问题d) 软件的开发、运行受到计算机系统的限制，不同程度地依赖于硬件和环境，导致了软件升级和移植地问题e) 软件复杂性越来越高f) 软件开发成本相当昂贵g) 大多数软件是新开发的，而不是通过已有的构件组装而来的h) 软件工程涉及诸多的社会因素4．遗留软件与软件的演化系统演化的原因:a) 系统需要修改其适应性，从而满足新的计算环境或者技术的需求b) 软件必须根据新的业务需求进行升级c) 软件必须扩展以具有与更多现代系统和数据库的协作能力d) 软件架构必须进行改建以适应多样化的网络环境30年来软件发展的规律：1、持续变化规律，2、复杂性增长规律，3、自我调控规律，4、组织稳定性守恒规律，5、保证通晓性规律，6、持续增长规律，质量衰减规律，7、反馈系统规律。

附录Software Engineering-A PRACTITIONER’S APPROACHWritten by Roger S. Pressman, Ph.D. （P.340-P.343）13.3DESIGN PRINCIPLESSoftware design is both a process and a model. The design process is a sequence ofsteps that enable the designer to describe all aspects of the software to be built. It is important to note, however, that the design process is not simply a cookbook. Creative skill, past experience, a sense of what makes “good” software, and an overallcommitment to quality are critical success factors for a competent design.The design model is the equivalent of an architect’s plans for a house. It begins by representing the totality of the thing to be built (e.g., a three-dimensional renderingof the house) and slowly refines the thing to provide guidance for constructing eachdetail (e.g., the plumbing layout). Similarly, the design model that is created for softwareprovides a variety of different views of the computer software.Basic design principles enable the software engineer to navigate the design process.Davis suggests a setof principles for software design, which have beenadapted and extended in the following list:• The design process should not suffer from “tunnel vision.” A gooddesigner should consider alternative approaches, judging each based on therequirements of the the resources available to do the job, and thedesign concepts presented in Section • The design should be traceable to the analysis model. Because a singleelement of the design model often traces to multiple requirements, it is necessaryto have a means for tracking how requirements have been satisfied bythe design model.• The design should not reinvent the wheel. Systems are constructed usinga set of design patterns, many of which have likely been encountered before.These patterns should always be chosen as an alternative to reinvention.Time is short and resources are limited! Design time should be invested inrepresenting truly new ideas and integrating those patterns that already exist.• The design should “minimize the intellectual distance”between the software and the problem as it exists in the real world.That is, the structure of the software design should (whenever possible)mimic the structure of the problem domain.• The design should exhibit uniformity and integration. A design is uniformif it appears that one person developed the entire thing. Rules of styleand format should be defined for a design team before design work begins. Adesign is integrated if care is taken in defining interfaces between designComponents.• The design should be structured to accommodate change. The designconcepts discussed in the next section enable a design to achieve this principle.• The design should be structured to degrade gently, even when aberrantdata, events, or operating conditions are encountered. Welldesignedsoftware should never “bomb.” It should be designed toaccommodate unusual circumstances, and if it must terminate processing, doso in a graceful manner.• Design is not coding, coding is not design. Even when detailed proceduraldesigns are created for program components, the level of abstraction ofthe design model is higher than source code. The only design decisions madeat the coding level address the small implementation details that enable theprocedural design to be coded.• The design should be assessed for quality as it is being created, notafter the fact.A variety of design concepts (Section 13.4) and design measures(Chapters 19 and 24) are available to assist the designer in assessing quality.• The design should be reviewed to minimize conceptual (semantic)errors. There is sometimes a tendency to focus on minutiae when the design isreviewed, missing the forest for the trees. A design team should ensure thatmajor conceptual elements of the design (omissions, ambiguity, inconsistency)have been addressed before worrying about the syntax of the design model.When these design principles are properly applied, the software engineer creates a designthat exhibits both external and internal quality factors . External quality factors are those properties of the software that can be readily observed by users (e.g., speed,reliability, correctness, usability).Internal quality factors are of importance to softwareengineers. They lead to a high-quality design from the technical perspective. To achieveinternal quality factors, the designer must understand basic design concepts.13.4 DESIGN CONCEPTSA set of fundamental software design concepts has evolved over the past four decades.Although the degree of interest in each concept has varied over the years, each hasstood the test of time. Each provides the software designer with a foundation fromwhich more sophisticated design methods can be applied. Each helps the softwareengineer to answer the following questions:• What criteria can be used to partition software into individual components?• How is function or data structure detail separated from a conceptual representationof the software?• What uniform criteria define the technical quality of a software design?M. A. Jackson once said: "The beginning of wisdom for a [software engineer] is torecognize the difference between getting a program to work, and getting it right". Fundamental software design concepts provide the necessary frameworkfor "getting it right."13.4.1 AbstractionWhen we consider a modular solution to any problem, many levels of abstraction canbe posed. At the highest level of abstraction, a solution is stated in broad terms usingthe language of the problem environment. At lower levels of abstraction, a more proceduralorientation is taken. Problem-oriented terminology is coupled with implementation-oriented terminology in an effort to state a solution. Finally, at the lowestlevel of abstraction, the solution is stated in a manner that can be directly implemented.Wasserman provides a useful definition:The psychological notion of "abstraction" permits one to concentrate on a problem atsome level of generalization without regard to irrelevant low level details; use of abstractionalso permits one to work with concepts and terms that are familiar in the problem environmentwithout having to transform them to an unfamiliar structure . . .Each step in the software process is a refinement in the level of abstraction of the software solution. During system engineering, software is allocated as an element ofa computer-based system. During software requirements analysis, the software solutionis stated in terms "that are familiar in the problem environment." As we movethrough the design process, the level of abstraction is reduced. Finally, the lowestlevel of abstraction is reached when source code is generated.As we move through different levels of abstraction, we work to create proceduraland data abstractions. A procedural abstraction is a named sequence of instructionsthat has a specific and limited function. An example of a procedural abstraction wouldbe the word open for a door. Open implies a long sequence of procedural steps (e.g.,walk to the door, reach out and grasp knob, turn knob and pull door, step away frommoving door, etc.).A data abstraction is a named collection of data that describes a data objectChapter12). In the context of the procedural abstraction open, we can define a data abstractioncalled door. Like any data object, the data abstraction for door would encompassa set of attributes that describe the door (e.g., door type, swing direction, peningmechanism, weight, dimensions). It follows that the procedural abstraction open wouldmake use of information contained in the attributes of the data abstraction door.Many modern programming languages provide mechanisms for creating abstractdata types. For example, the Ada package is a programming language mechanismthat provides support for both data and procedural abstraction. The original abstractdata type is used as a template or generic data structure from which other data structurescan be instantiated.Control abstraction is the third form of abstraction used in software design. Likeprocedural and data abstraction, control abstraction implies a program control mechanismwithout specifying internal details. An example of a control abstraction is the synchronization semaphore used to coordinate activities in an operating system.The concept of the control abstraction is discussed briefly in Chapter 14.13.4.2 RefinementStepwise refinement is a top-down design strategy originally proposed by Niklaus Wirth. A program is developed by successively refining levels of procedural detail.A hierarchy is developed by decomposing a macroscopic statement of function (aprocedural abstraction) in a stepwise fashion until programming language statementsare reached. An overview of the concept is provided by Wirth: In each step (of the refinement), one or several instructions of the given program are decomposedinto more detailed instructions. This successive decomposition or refinement of specificationsterminates when all instructions are expressed in terms of any underlying computeror programming language . . . As tasks are refined, so the data may have to be refined,decomposed, or structured, and it is natural to refine the program and the data specificationsin parallel.Every refinement step implies some design decisions. It is important that . . . the programmerbe aware of the underlying criteria (for design decisions) and of the existence ofalternative solutions . . .The process of program refinement proposed by Wirth is analogous to the process of refinement and partitioning that is used during requirements analysis. The differenceis in the level of implementation detail that is considered, not the approach.Refinement is actually a process of elaboration.We begin with a statement offunction(or description of information) that is defined at a high level of abstraction. Thatis, the statement describes function or information conceptually but provides no informationabout the internal workings of the function or the internal structure of theinformation. Refinement causes the designer to elaborate on the original statement,providing more and more detail as each successive refinement (elaboration) occurs.Abstraction and refinement are complementary concepts. Abstraction enables adesigner to specify procedure and data and yet suppress low-level details. Refinementhelps the designer to reveal low-level details as design progresses. Both conceptsaid the designer in creating a complete design model as the design evolves.《软件工程-实践者的研究方法》Roger S. Pressman博士(340页-343页)13.3 设计原则软件设计是一个过程也是一个模型。