《系统工程简答题》word版.doc

(1)Four Basic Attributes of the System1 Assemblage: A system consists of a plural number of distinguishable units (elements, components, factors, subsystems, etc.), which may be physical or conceptual, natural or artificial. School systems2 Relationship: The systems point of view also recognizes that a problem and its solution have many elements or components, and there are many different relations among them. For example, grades are one mechanism（机制） for interaction between professors and students. Grades serve a purpose, intended or not。3 Goal-seeking: An actual system as a whole performs a certain function or aims at single or multiple objectives. An objective that is measurable by any means is called a goal/target. A 'manufacturing system' effectively converts resources of production into produced goods (products), attaining an objective that creates high utilities by adding values to the raw materials, resulting in superior quality, cost and delivery. 4 Adaptability to environment: A specific, factual system behaves so as to adapt to the change in its surroundings, or external environment. A 'business system' is a self-organizing system, in that it generates a diversified variety of activities, resulting in economies of scope. (2)Systems Defined1 Abstract (or basic) definition: A system is a collection of recognizable units having relationships among the units.2 Structural (or static) definition: A system is a collection of recognizable units having relationships among the units, aiming at specified single or multiple objectives subject to its external environment. 3 Transformational (or functional) definition: A system receives inputs from its environment, transforms them to outputs, and releases the outputs to the environment, whilst seeking to maximize the productivity of the transformation4 Procedural (or dynamic) definition: A system is a procedure-a series of chronological, logical steps by which all repetitive tasks are performed.(3)systems engineering knowledge comprised1 knowledge principles 2 Knowledge practices 3 Knowledge perspectives(4) methodological frameworks and life cycles3 phases: definition, development, deployment3 steps: issue formulation, issue analysis, issue interpretationLife cycles: system planning and marketing; research, development, test and evaluation; system acquisition or production.(5) The general situation assessment process 1 We make general observations of as many pertinent（有关的） aspects of the situation around us as is possible in order to identify or confirm the descriptive scenario or status quo（现状）.2 We see if this information indicates a change in the current situation. If there is no change, we go back to step 1. If there is a change, we proceed to step 3.3 We identify or formulate a number of alternative hypotheses that may describe the new situation, or descriptive scenario.4 We attempt to determine if any more information inputs are required for deciding which alternative hypothesis is the most likely one.5 We obtain the required information from such input sources as a priori predefined stored information, human observations, human knowledge, or sensor measurements.6 We process this information and knowledge to confirm or disconfirm each of the alternative hypotheses.7 We identify the hypotheses with the highest probability (ies) of being true and identify the associated situation assessment with some appropriate quantification of our confidence in the assessment.8 We determine if the assessment confidence for describing the situation is sufficiently high. If it is not, we go back to step 3 or 4 and repeat the assessment process until the confidence threshold is achieved. When it is, we have assessed the situation and we go on with the rest of the problem-solving or issue formulation process. (6)System definition matrixA convenient way for the systems engineer to document the scoping and bounding of a problem is to use a systems definition matrix like the one shown in Figure 3.4. The matrix has two main sections. One section defines the scope of the project by listing the needs, objectives, and criteria. The other section lists the parameters, variables, and constraints and defines the bounds of the project. The simple framework of the systems definition matrix is useful as a checklist for information gathering, documentation, and communication.(7)Logical Steps of Systems Engineering Formulation: problem definition, value system design, system synthesis Analysis: System Analysis and Modeling, Refinement of the Alternatives.Interpretation: Decision Making, Planning for Action.