Abstract
After the Great East Japan Earthquake 2011 infrastructural recovery and reconstruction have been delayed, and that is considered to be caused by insufficient systems of consensus-building or decision-making. The purpose of this paper is to propose a cooperative decision-making method by applying α–level set based on the principle of majority decision and the representative democracy. Concretely the proposed decision-making is performed by public opinion and a decision-maker (ex. government). The former is given by α – level set of acceptable opinion distribution and the latter is by non-fuzzy function of independent variables with dimension less than the former's. In this paper the cases of α–level sets with 1, 2 and 3 dimensions are discussed. As for the case of 1 dimension, algorithms and rules are described rigorously, and in the cases of 2 and 3 dimensions discussions are performed spatially and qualitatively. The features of the proposed method are that the responsibility and competence of public opinion and decision-maker are made clear and that the processes of decision-making are described objectively and visibly. Finally its applicability to aseismic planning of infrastructures and its social significance and prospect are discussed.
