系统工程第三章

,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,2007 SYSTEMS ENGINEERING,*,Chapter3,Formulation of Issues,1,2007 SYSTEMS ENGINEERING,1,INTRODUCTION,It is very important,we believe,that,texts on systems engineering and problem solving,in general,pay significant attention to issue formulation,as a step in systems engineering that needs to occur in each of the phases of effort.,This is so because,in practice,the results of a poor issue formulation effort may be subject to very detailed analysis,and the results of this are carried over into implementation,.,As a result,we obtain the wrong system!,Needless to say,this usually results in a waste of resources and(through engineering)an inferior system,compared to that which might have resulted from a better issue formulation.,Issue formulation is critical across the definition,development,and deployment phases of a systems engineering life cycle,.This is not a step implemented only as part of the systems definition phase,although it is very important in that phase.,10/10/2024,2,2007 SYSTEMS ENGINEERING,1,INTRODUCTION,A,problem,or an,issue,as a generally synonymous term,can usually be viewed from several perspectives,and the solution that results will often be a strong function of the perspectives from which a problem is viewed and formulated.,10/10/2024,3,2007 SYSTEMS ENGINEERING,1,INTRODUCTION,Issue formulation begins with a definition of the problem or issue to be resolved,.,This includes an assessment of the situation surrounding the problem.Situation assessment is important in problem solving and issue resolution.There are many aspects of the environment surrounding an issue that we need to know about in order to be able to generate potentially feasible alternative courses of action that can lead to issue resolution.Many of these factors are dynamic,uncertain,and subject to change with the passage of time.,Situation assessment means that we need to make a careful appraisal of the various factors that influence a particular observed state or condition,.Generating good alternatives,ones that truly satisfy the needs of our customers in an effective,efficient,equitable,and explicable manner,depends on an indepth situation assessment.,10/10/2024,4,2007 SYSTEMS ENGINEERING,2 SITUATION ASSESSMENT,Complete situation assessment consists of three basic steps that are intended to answer the three questions highlighted in Figure 3.1.,10/10/2024,5,2007 SYSTEMS ENGINEERING,2 SITUATION ASSESSMENT,The first part is the identification of the(immediate)past in terms of the question,What was?,The second part of a situation assessment examines the current status or position of things relative to the goal.It is a descriptive component and answers the question,What is,?,The third or normative component of a situation assessment answers the question,What ought to be,?,Understanding of the major,ideally all,factors influencing the past,present,and future is needed for a good situation assessment.There is a horizon component of situation assessment and it answers the question,What factors over time matter and when do they matter?,10/10/2024,6,2007 SYSTEMS ENGINEERING,2 SITUATION ASSESSMENT,We have a complete situation assessment once we know the following:,What do we want to accomplish?,What is the past and current state of affairs relative to our goal brought about by the changed situation?,What are the relevant factors that influence the situation and their associated time frame.,10/10/2024,7,2007 SYSTEMS ENGINEERING,2 SITUATION ASSESSMENT,There are a large variety of environments in which various systems must operate.,A number of different perspectivessuch as technical,economic,legal,political,cultural,and socialcan be important for understanding a systems environment.,When an adequate appreciation of all the important perspectives is achieved,then we say we have preserved the contextual integrity of the issues under consideration.The problem of issue definition,and the resulting identification of worthwhile alternatives,depends on an accurate and timely situation assessment that preserves this contextual integrity,.,10/10/2024,8,2007 SYSTEMS ENGINEERING,2 SITUATION ASSESSMENT,Accomplishing a high-quality situation assessment depends on several factors.,First,the experiential familiarity with the issues or problem under consideration is very important.,For example,it is unlikely that someone with very little background knowledge about nuclear power plants would be able,without considerable study,to develop useful alternatives for ensuring safe operation of such a facility.,As we have already noted,knowledge is information in a relevant context.,10/10/2024,9,2007 SYSTEMS ENGINEERING,2 SITUATION ASSESSMENT,But you need more than just knowledge about the specific problem or issue at hand.,Familiarity with the environment into which the specific issue or problem is embedded is also crucial to an understanding of context.,For example,the design of a successful information system for airlin