Abstract
Because water use systems include a variety of stakeholders, we must present multiple alternative plans that to diverse preferences. Hence, we prepared multiple evaluation axes of water use systems. We developed multi-objective optimization systems that to caluculate multiple alternatives of water use systems by using evaluation model of multiple aspects. We applied cost, water pollution substances, global warming and so on for objective functions, and we applied wastewater treatment plant, supply pipe, treatment plant and so on for design variables. Then, we examined the calculation set using 1,000 sets of random numbers as weighting coefficients and 12 sets of mono-objective optimization. As a result, we could develop multi-objective optimization system. This system can be presented multiple alternatives for stakeholders of multiple preferences. And, we could get 71 Pareto optimal solutions using alternatives by deletion of overlap solutions. These solutions are complementary with each weighting coefficient. These solutions contain unexpected solutions at the stage of weighting by each preferece. These solutions containts multiple value of objective functions and multiple number of dasign variable. Then, we can use these solutions for alternative of decision-making.
