[工学]通信软件设计_01 MSC.ppt

* * * * * * * * * * * The domain is NOT a solution and does not identify the system to be. The first purpose is to understand needs and how a system can help to satisfy them. Domain descriptions is a means to analyse the domain, and to identifuy needs. It is also a means for communication and common understanding that can be shared by all stakeholders. Finally it may hold for several system families developed for the domain and thereby provide a basis for reuse. By analysing the domain we may specify a system (family), which is the first step in systems development. Systems descriptions are then elaborated into complete definitions of the system (family) to be, precise and detailed enough to actually manufacture the system. Quality is defined as satisfaction of needs; which is the ultimate goal. We call it system quality as opposed to process quality which is defined as confomance with specifications. Note here that we deal with a reality and with descriptions of reality. Systems development is mainly concerned with the descriptions. They are the means for understanding, communication, analysis and synthesis. Using a limited set of COMMON descriptions help to improve the precision and to reduce errors, compared to a situation where each group of stakeholder make their own (marketing, development, sales, users,…) which is the case in many companies. * The idea here is to stimulate the students to start thinking themselves and to discuss the issues. There are no silver bullett, as most factors are necessary for success, but some are more critical than others. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * connector layer ::= { message area* | incomplete message area* | method call area* | incomplete method call area* | reply area* | incomplete reply area*} set Message消息，event事件 Output event Input event g User AC System Code OK msc User_accepted Unlock Card out Idle Door unlocked Message Messages 有一个output event和一个input eve