模糊理論與成本效益分析方法之整合應用

Abstract

成本效益分析（Cost-Benefit Analysis，CBA）是計畫評估的方法之一 ，在決策程序中扮演一個極其重要的角色，其主要目的是提供一評估指標 ，以表達計畫方案的成效，由於利用「貨幣價值」的表現方式，可讓決策 者能輕易且直接的判斷結果。因此在方案評估過程中，「貨幣化」的評估 方式有其實用價值。 然而在貨幣化的衡量過程中，由於沒有辦法達到非常完善的考量，使得部 份投入參數值會因為資訊不完全的影響而有不同衡量的結果，甚而可能導 致錯誤的決策判斷，在日趨複雜之社會與經濟環境下﹐投資計畫之評估與 選擇﹐通常是在糢糊環境下進行，如何處理其由於不確定性所產生的不同 價值判斷，實屬一重要課題。 本研究是以過去傳統的成本效益分析方法做為主要研究對象，針對方案評 估過程中具有資訊不完全性的投入參數，應用模糊理論方法做一適當處理 ，以研擬一個方案評估的整合模式，針對各個階段分別採用相似形整合法 、模糊數之函數算則以及將模糊數轉為明確值的方法，可得到各方案的績 效評估值及其信心指數，並應用最大集合及最小集合所對應之效用值進行 模糊數的排序，提出最佳方案決策，最後以公有路外停車場投資計畫為一 簡例應用，進行模式的實際操作，說明本研究所提出的整合模式，如何應 用於投資計劃之評估。 Cost-Benefit Analysis ( CBA ) is one of the methods for evaluating alternatives , and it plays rather significant role in the process of decision making , and the primary of which would be to offer an evaluation index that can help demonstrate the effect of the planned alternative. Due to the fact that the manner of monetary value is employed for demonstration, it could than allow the decision makers to come to the judgment results easily and directly. As a result, the manner of evaluation by monetization during the process of alternative evaluation can be found of its practical value. Only during the measurement process of monetization, part of the input parameter values would have come out with various measurement results as of the influences of insufficient information, and sometimes it might ever lead to erroneous decision making judgment. In addition, the evaluation and selection of investment alternatives, under ever complex social and economic environments, has become an increasingly important issue as how diverse value judgments brought forth from uncertainty can be well taken of.This study would mainly base on the conventional cost and benefit analysis methods of the past as its major objects of measurement then fuzzy theory would be utilized, in view of the input parameters with insufficient information during the process of alternative evaluation, for a proper administration so as to formulate an integrated model for alternative evaluation. Furthermore, similarity aggregation method, function principle of the fuzzy numbers, and the transformation of fuzzy numbers into crisp values would be employed in each of the stages, so that the performance evaluation values as well as the confidence indices for each of the alternatives can be obtained. Also, the corresponding utility values to the maximizing set and minimizing set are exploited to conduct the ranking of fuzzy numbers so as to out forward the optimal decision making for the alternative. At the end, the investment alternative of public off-road parking lot is employed as an example for illustration as well as for the practical operation of the model, which will elucidate how the integrated model put forward in this study can apply itself on the evaluation for investment alternatives.