Graph-Matrix Method in Environmental Assessment

Abstract

Lately in the field of environmental assessment, the impact analysis of actions or alternatives on the value of the environment which surrounds the actions has been a focal issue. An action or alternative means any kind of decision concerned with planning, design, construction or manipulation of an environmental system. Each action or alter native must be judged on the basis of how well it satisfies some goal. Goal satisfaction is to be determined by measuring each alternative with respect to a set of interrelated and often conflicting objectives. Firstly the paper presents a new graph-matrix method to evaluate the interrelationship among the objectives, and the degree of contribution of each objective to the goal. One of the advantages of the method over the conventional ones such as “Cross-Support Matrix”, “Cross-Relevance Matrix” or “CrossImpact Matrix” method is in its feature that not only direct or obvious dependencies among objectives but also indirect or hidden dependencies can be easily evaluated. The simplicity of computer implementation is another advantage of the method. Secondly the proposed graph-matrix method is applied to and is illustrated by an environmental assessment problem with multiple objectives. The original weights which represent the intuitive relative importance of the subgoals are modified by taking the effect through the mutual influence among the items into consideration. Finally the procedure for approximating the multiattribute utility function without independence conditions by means of identifying the influence matrix among the attributes and modifying the initial weights is proposed along with an example.