• 산업경영시스템학회지
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• 제44권2호
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• pp.24-35
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• 2021

Due to increasing awareness on the treatment of end-of-use/life products, disassembly has been a fast-growing research area of interest for many researchers over recent decades. This paper introduces a novel lot-sizing problem that has not been studied in the literature, which is the service-parts lot-sizing with disassembly option. The disassembly option implies that the demands of service parts can be fulfilled by newly manufactured parts, but also by disassembled parts. The disassembled parts are the ones recovered after the disassembly of end-of-use/life products. The objective of the considered problem is to maximize the total profit, i.e., the revenue of selling the service parts minus the total cost of the fixed setup, production, disassembly, inventory holding, and disposal over a planning horizon. This paper proves that the single-period version of the considered problem is NP-hard and suggests a heuristic by combining a simulated annealing algorithm and a linear-programming relaxation. Computational experiment results show that the heuristic generates near-optimal solutions within reasonable computation time, which implies that the heuristic is a viable optimization tool for the service parts inventory management. In addition, sensitivity analyses indicate that deciding an appropriate price of disassembled parts and an appropriate collection amount of EOLs are very important for sustainable service parts systems.

• 한국경영정보학회:학술대회논문집
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• 한국경영정보학회 2007년도 International Conference
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• pp.160-167
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• 2007

전자상거래에서 핵심적인 연구질문 중의 하나는 서비스품질에 영향을 주는 핵심 driver가 무엇인가를 이해하는 것이다. 이 연구에서는 인터넷 쇼핑몰의 관리기능 변수를 파악하고 그것이 서비스품질의 4개의 각 세부요소에 어떻게 영향을 끼치는가를 조사한다. 본 연구에서는 기존문헌을 토대로 서비스품질의 각 세부요소에 영향을 미치는 7개의 선행변수를 도출하였다:배달(delivery), 제품반품(reverse logistics), 불만처리(claim resolving), 추천(recommendation), 고객맞춤화(customization), 상호작용성(interactivity), 접촉(contact). 실증적 테스트결과 이 선행변수들은 모두 서비스품질의 각 세부요소에 유의한 결과를 나타냈으며 이는 어떻게 서비스품질의 수준이 관리될수 있는지에 대한 이해를 돕는데 도움을 줄 것이다.

• 한국경영과학회지
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• 제31권3호
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• pp.81-96
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• 2006

We consider a rental company that dynamically manages Its capacity level through capacity addition and return While serving customer with its own capacity, the company expands its capacity by renting items from an outside source so that it can avoid lost opportunities of rental which occur when stock is not sufficient. If stock becomes sufficiently large enough to cope with demands, the company returns expanded capacity to the outside source. Formulating the model into a Markov decision problem, we identify an optimal capacity management Policy which states when the company should expand its capacity and when it should return expanded capacity after capacity addition. Since it is intractable to analytically find the optimal capacity management policy and the optimal size of capacity expansion, we present a numerical procedure that finds these optimal values based on the value iteration method. Numerical analysis is implemented and we observe monotonic properties of the optimal performance measures by system parameters, which are meaningful in developing effective heuristic policies.

• 한국경영과학회지
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• 제35권4호
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• pp.17-31
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• 2010

This study investigates two-stage return policy and recycling issues in an e-marketplace supply chain consisting of consumers, a retailer and a manufacturer. The manufacturer, a focal company in the e-marketplace supply chain, considers the recycling of commercial returns so offers the retailer a buy-back contract of which transfer payment consists of a wholesale price and a buy-back price. Then, under the given contract offer, the retailer determines a selling price and a return policy to control consumers' demand and return requests. We consider the retailer's opportunistic behavior and supply chain coordination issues based on the principal-agent paradigm. We compare the first-best and second-best optima and conduct comparative static analyses to evaluate the performance results of the buy-back contract and provide important managerial implications.

• 한국경영과학회지
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• 제39권4호
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• pp.153-165
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• 2014

We present a new framework for rental capacity management in which rental capacity is dynamically managed by means of temporary inventory addition/return. While serving customers with its own (native) capacity, the rental firm rents additional rental capacity from an upper echelon rental company so that it can avoid lost sales which may occur when stock is not sufficient, and returns it when stock becomes sufficiently large enough to cope with demands. Formulating the model as a Markov decision process, we investigate a flexible capacity addition/return policy that maximizes the firm's profit with respect to system costs. Numerical study indicates that rental operation with capacity addition/return can be economically favorable over rental operation without capacity expansion/return and can contribute the reduction in the size of native rental capacity.

• 산업경영시스템학회지
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• 제31권3호
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• pp.90-100
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• 2008

기간차량경로 문제는 차량용량제약을 고려한 차량경로문제를 다 기간으로 확장한 형태의 문제로 역방향 로지스틱스의 폐기물 혹은 재활용품 수거에 관련된 주요한 운영 문제들 중의 하나로 각 고객에 대해서는 계획기간 중에 방문해야 하는 횟수가 정해져 있어 방문날짜 조합을 결정해야 하며 주어진 방문날짜 조합 하에 각 기간의 차량경로도 결정해야 한다. 주요한 제약조건으로는 차량의 용량제약과 각 기간의 가용 시간제약이 있으며 소요차량의 대수를 최소화하는 것을 목적으로 한다. 본 연구에서는 대상 문제의 복잡도로 인하여 초기해를 구하고 그 해를 개선하는 2 단계 발견적 알고리듬을 제안하였으며 다양한 문제들에 대한 계산실험 결과 본 연구에서 제안하고 있는 발견적 알고리듬이 기존 알고리듬보다 우수함을 보였다.

• 대한산업공학회지
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• 제34권4호
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• pp.398-407
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• 2008

We consider a product recovery system that a single product is stocked in order to meet a demand from customers who may return products after usage. This paper addresses a problem of when to release a procurement process to replenish serviceable inventory and how many new products to procure. The structure of the optimal procurement policy is examined and numerically identified as a monotonic threshold curve. A numerical procedure is presented to jointly find the optimal procurement order size, optimal procurement policy, and optimal discounted profit. Sensitivity analysis also indicates that these optimal performance measurements have monotonic properties with respect to system parameters.

• 대한산업공학회지
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• 제33권3호
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• pp.312-321
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• 2007

We address a disposal issue of returned products in a product recovery system where a single product is stocked in order to meet a demand from customers who may return products after usage. Product returns occur randomly and can be accepted for remanufacturing or disposed of depending on the state of the system. We examine the structure of the optimal disposal policy for returned product that utilizes the information of the inventory of both serviceable and remanufacturable products. Numerical study indicates that it can be characterized by a monotonic threshold type of the curve. A disposal is allowed only when the remanufacturable inventory level exceeds a threshold which is the function of the inventory level of serviceable product and it is decreasing as the serviceable inventory level increases. Sensitivity analysis also indicates that the optimal disposal policy and the optimal profit have monotonic properties with respect to system parameters.

• Industrial Engineering and Management Systems
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• 제7권1호
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• pp.78-89
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• 2008

The need for holistic modeling efforts for returns that capture the extended closed loop supply chain (CLSC) system at strategic as well as operational level has been clearly recognized by the industry and academia. Strategic decision-makers need comprehensive models that can guide them in efficient decision-making to increase the profitability of the entire forward and return chain. Therefore, determination of a near optimal design configuration, which includes the environmental, economical and technological capability factors, is important in strategic decision-making effort that affect the profitability of the closed loop supply chain. In this paper, we adopted an improved system dynamics methodology to tackle strategic issues that affect various performance measures, like market, time/cost, environment etc., for closed loop supply chains. After studying real life implementation issues in CLSC design, we presented guidelines for the PBM (Participative Business Modeling) methodology and presented its extension for the strategic dynamic system modeling of return chains. Finally, we demonstrated the measurement of operational performance by extending SD (system dynamic) application to closed loop supply chain management.

• 산업경영시스템학회지
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• 제29권1호
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• pp.76-86
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• 2006

다양한 데이터 마이닝 기법들의 발전과 더불어, 속성(Feature 또는 Attribute)의 범위(Dimension)를 줄이기 위해 많은 요소 선택 방법이 개발되었다. 이는 확장성(Scalability)을 향상시킬 수 있고 학습 모델(Learning Model)을 더욱 쉽게 해석할 수 있도록 한다. 이 논문에서는 네스티드 분할(Nested Partition, 이하 NP)을 이용한 새로운 최적화 기반 속성 선택 방법을 NP 기본 구조와 다양한 실험 문제의 수치적 결과들과 함께 제시하여 어떻게 NP의 최적화 구조가 속성 선택 과정에 기여를 하고 있는지 보여준다. 그리고 이 새로운 지능적인 분할 방법이 어떻게 매우 효율적인 분할을 수행하는지를 제시한다. 이 새로운 속성 선택 방법은 필터(Filter)방법과 래퍼(Wrapper)방법 두 가지로 구현될 수 있다. 사례 연구로서, B2B e-비즈니스 시스템에서 효과적으로 사용될 수 있는 추천 시스템(Recommender System)을 제안하였다. 이 추천 시스템은 분류 기법(Classification Rule)과 제시된 NP 기반 요소 선택 방법을 사용하고 있다. 이 추천 시스템은 사용자의 인터넷 경매 참여를 추천하는데 사용되며, 이 때 제안된 요소 선택 앨고리듬은 추천 규칙들이 쉽게 이해될 수 있도록 모델을 간략화 하는데 사용된다.