Use of fuzzy logic assessment for high consequence implementation risk analysis

摘要

''High consequence'' operations are systems, structures, and/or strategies for which it is crucial to provide assured protection against some potential catastrophe or catastrophes. The word ''catastrophe'' implies a significant loss of a resource (e.g., money, lives, health, environment, national security, etc.). The implementation of operations that are to be as catastrophe-free as possible must incorporate a very high level of protection. Unfortunately, real world limitations on available resources, mainly money and time, preclude absolute protection. For this reason, conventional ''risk analysis'' focuses on ''cost-effective'' protection, demonstrating through analysis that the benefits of any protective measures chosen outweigh their cost. This is a ''crisp'' one-parameter (usually monetary) comparison. A major problem with this approach, especially for high consequence operations, is that it may not be possible to accurately determine quantitative ''costs,'' and furthermore, the costs may not be accurately quantifiable. Similarly, it may not be possible to accurately determine or to quantify the benefits of protection in high consequence operations. These weaknesses are addressed in this paper by introducing multiple parameters instead of a single monetary measure both for costs of implementing protective measures and their benefits. In addition, a fuzzy-algebra comparison based on fuzzy number theory is introduced as a tool in providing cost/benefit tradeoff depiction, with the incorporation of measures of the uncertainty that necessarily exists in the input information. The result allows a more informative comparison to be made through use of fuzzy results, especially at the extreme bounds of the uncertainty.