분해 공정 및 일정계획 문제의 통합: 기본 및 확장모형

Abstract

We consider two interrelated problems occurred in disassembly systems: disassembly leveling and disassembly lot-sizing for multiple product types. Disassembly leveling, one of disassembly process planning decisions, is to determine disassembly structure that specifies parts and/or subassemblies to be obtained from products, and disassembly lot-sizing, one of disassembly scheduling decisions, is the problem of determining the amount of disassembly operations to satisfy the demands of parts and/or subassemblies. For disassembly leveling, in particular, we consider a general case that disassembly levels may be different even for the same product type. Unlike most existing studies, this thesis considers the two problems at the same time for the objective of minimizing the sum of disassembly setup and operation costs. Two cases for the integrated problem are considered. The first one is the basic problem without parts commonality. For this case, an integer programming model is suggested and then a simple polynomial-time optimal algorithm is suggested. The second one is an extended problem with parts commonality. For the extended case, we show that the problem is NP-hard, and due to its complexity, a simple heuristic is suggested. Test results on a number of randomly generated instances are reported.