【正文】 e solution that results will often be a strong function of the perspectives from which a problem is viewed and formulated. 上午 4時(shí) 12分 2022 SYSTEMS ENGINEERING 4 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. 上午 4時(shí) 12分 2022 SYSTEMS ENGINEERING 5 2 SITUATION ASSESSMENT Complete situation assessment consists of three basic steps that are intended to answer the three questions highlighted in Figure . 上午 4時(shí) 12分 2022 SYSTEMS ENGINEERING 6 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 ponent and answers the question, What is? ? The third or normative ponent 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 ponent of situation assessment and it answers the question, What factors over time matter and when do they matter? 上午 4時(shí) 12分 2022 SYSTEMS ENGINEERING 7 2 SITUATION ASSESSMENT We have a plete situation assessment once we know the following: ? What do we want to acplish? ? 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. 上午 4時(shí) 12分 2022 SYSTEMS ENGINEERING 8 2 SITUATION ASSESSMENT There are a large variety of environments in which various systems must operate. A number of different perspectives— such as technical, economic, legal, political, cultural, and social— can be important for understanding a system39。 ? if it is not benign, we may decide to react to it or continue to observe it. A reasonably good illustration of this is the situation assessment of temperature of the human body. One of the potential difficulties relative to observing a situation is that we wish to be able to interactively and proactively deal with issues and not simply to react to difficulties after they have eventuated. 上午 4時(shí) 12分 2022 SYSTEMS ENGINEERING 18 3 APPROACHES TO SITUATION ASSESSMENT The general situation assessment process , illustrated in Figure , be described by the following eight steps: I. We make general observations of as many pertinent（有關(guān)的） aspects of the situation around us as is possible in order to identify or confirm the descriptive scenario or status quo（現(xiàn)狀） . II. 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. III. We identify or formulate a number of alternative hypotheses that may describe the new situation, or descriptive scenario. IV. We attempt to determine if any more information inputs are required for deciding which alternative hypothesis is the most likely one. 上午 4時(shí) 12分 2022 SYSTEMS ENGINEERING 19 3 APPROACHES TO SITUATION ASSESSMENT V. We obtain the required information from such input sources as a priori predefined stored information, human observations, human knowledge, or sensor measurements. VI. We process this information and knowledge to confirm or disconfirm each of the alternative hypotheses. VII. 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. VIII. 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 problemsolving or issue formulation process. 上午 4時(shí) 12分 2022 SYSTEMS ENGINEERING 20 3 APPROACHES TO SITUATION ASSESSMENT 上午 4時(shí) 12分 2022 SYSTEMS ENGINEERING 21 3 APPROACHES TO SITUATION ASSESSMENT One of the most difficult problems in plex decision situations is gathering the appropriate information and properly assessing the situation. Mason and Mitroff are among the many who have mented on this reality. These authors identify three types of errors that can occur in assessing a situation: ? Type I errors are errors that result from incorrectly assessing that there is a problem when there is no problem. ? Type II errors are errors that result from incorrectly assessing that there is no problem when there is a problem. ? Type III errors are errors that result from correctly assessing that there is a problem, but incorrectly identifying the nature of the problem. 上午 4時(shí) 12分 2022 SYSTEMS ENGINEERING 22 3 APPROACHES TO SITUATION ASSESSMENT ? Type I errors are generally called false ala