GRAY FUZZY DYNAMIC-PROGRAMMING - APPLICATION TO MUNICIPAL SOLID-WASTEMANAGEMENT PLANNING PROBLEMS

This paper integrates the concepts of grey systems and fuzzy sets into optimization analysis by dynamic programming as a means of accounting for system uncertainty. The developed grey fuzzy dynamic programming (GFDP) model improves upon previous DP methods by allowing uncertain i nput information to be directly communicated into the optimization pro cess and solutions through the use of different alpha-cut levels of fu zzy numbers for the input fuzzy information, and the use of a grey fuz zy linear programming (GFLP) method for an embedded LP problem. The mo delling approach is applied to a hypothetical problem for the planning of waste flow allocation and treatment/disposal facility expansion wi thin a municipal solid waste management system. The solutions of the G FDP model corresponding to different alpha-cut levels provide optimal decisions regarding different development alternatives in a multi-peri od, multi-facility and multi-scale context, as well as the upper and l ower limits of waste flow allocation. The results indicate that reason able and useful solutions can be achieved through the developed GFDP a pproach.