系統工程第二章ppt課件(編輯修改稿)

　

【文章內容簡介】 Associated with a methodology is a structured framework into which particular methods are associated for resolution of a specific issue. 上午 4時 12分 2022 SYSTEMS ENGINEERING 23 METHODOLOGICAL FRAMEWORKS FOR SYSTEMS ACQUISITION OR PRODUCTION Let us now develop the structured framework of steps, phases, and stages in systems engineering in more detail. 上午 4時 12分 2022 SYSTEMS ENGINEERING 24 (1) Logical Steps of Systems Engineering As we have noted, all characterizations of systems engineering will necessarily involve three logical steps [14]: ? Formulation of the systems engineering problem under consideration ? Analysis to determine the impacts of the alternatives ? Interpretation of these impacts in accordance with the value system of the decision maker(s), and selection of an appropriate plan of action to continue the effort. These three steps, or an expansion thereto to more explicitly indicate the actual activities associated with each phase, are conducted at each and every phase of the systems engineering life cycle. 上午 4時 12分 2022 SYSTEMS ENGINEERING 25 (1) Logical Steps of Systems Engineering We can expand （擴展） the three fundamental steps of systems engineering in many ways. However, probably the most useful expansion is the seven steps identified by Hall [5]. Our construal(解釋 ) of these seven steps of systems engineering and their relation to the three basic steps of formulation, analysis, and interpretation follows. 上午 4時 12分 2022 SYSTEMS ENGINEERING 26 (1) Logical Steps of Systems Engineering Formulation ① Problem Definition. （ 問題的定義 ） This step involves isolating （分離） , quantifying （量化） , and clarifying （闡述） the need that creates the problem and describing the set of environmental factors that constrains alterables （約束變量） for the system to be developed. It involves identifying a set of needs, alterables, and constraints associated with the issue formulation. ② Value System Design. （ 價值系統設計 ） This step involves selection of the set of objectives or goals that guides the search for alternatives. Value system design enables determination of the multidimensional attributes or decision criteria for selecting the most appropriate system. It involves the identification and validation （確認） of a set of objectives and objectives measures. ③ System Synthesis. （ 系統綜合 ） This step involves searching for, or hypothesizing （假定、猜測） , a set of alternative courses of action or options. Each alternative must be described in sufficient detail to permit analysis of the impacts of implementation and subsequent evaluation and interpretation with respect to the objectives. As part of this step, we identify a number of potential alternatives and associated alternatives measures. 上午 4時 12分 2022 SYSTEMS ENGINEERING 27 (1) Logical Steps of Systems Engineering Analysis ④ System Analysis and Modeling （ 系統分析與建模 ） . As a part of this step, we determine specific impacts （確定具體的影響因素） or consequences of the alternatives （變量結果） that were specified as relevant to the issue under consideration by the value system. These impacts may relate to such important concerns as product quality, market, reliability, cost, and effectiveness or benefits. There are a variety of simulation and modeling methods, and a great variety of operations research approaches that are of potential value here. ⑤ Refinement of the Alternatives （ 細化變量 ） . As part of this step, we attempt to adjust, and hopefully optimize, the system variables in order to best meet system objectives and satisfy system constraints. 上午 4時 12分 2022 SYSTEMS ENGINEERING 28 (1) Logical Steps of Systems Engineering Interpretation ⑥ Decision Making （ 制定策略 ） . This step involves evaluating the impacts or consequences of the alternatives and, thereby, interpreting the alternatives in terms of the extent to which they achieve objectives. The alternatives are identified in system synthesis and subsequently modeled and refined in the analysis steps of effort, in accordance with satisfaction of objectives associated with the value system. This enables interpretation of these evaluations such that all alternatives can be pared relative to human values. One or more alternatives, or courses of action, can then be selected for advancing to the next step. ⑦ Planning for Action. This step involves municating the results of the effort to this point and looking ahead to the next phase of the systems engineering life cycle under consideration. This includes such pragmatic efforts as scheduling subsequent efforts, allocating resources to acplish them, and setting up system management controls. If we are conducting a single phase effort, this step would be the final one. More generally, it leads to a new phase of effort in continuation of a systems engineering life cycle. 上午 4時 12分 2022 SYSTEMS ENGINEERING 29 (1) Logical Steps of Systems Engineering figure indicates the waterfall nature of these seven steps of systems engineering and their relation to the three fundamental logical steps. The seven steps of systems engineering are generally carried out in an iterative fashion for each phase of the systems engineering life cycle. 上午 4時 12分 2022 SYSTEMS ENGINEERING 30 (1) Logical Steps of Systems Engineering Because the efforts and purposes of the various phases of the life cycle are quite different, the specific tools and methods that are appropriate to acplish each of the seven steps can be expected to be quite different from one systems engineering process phase to another. It is quite possible to go back to refine and improve the results of any earlier step as a consequence of the results of any later step. We do not show the