A Discount Policy for Perishable Items Sold from Two Shops

이가람(Ga Ram Lee),오용희(Yonghui Oh),황학(Hark Hwang) 한국경영과학회 2008 韓國經營科學會誌 Vol.33 No.2

This paper deals with two shops dealing with single perishable product:the fresh items are sold at a list price in the primary shop and the unsold items that have reached a certain allowed age are transferred to the secondary shop to be sold at a discounted price. It is assumed that the demand rates in two shops are independent each other and can be expressed as a function of inventory level and price. With the objective of maximizing the profit under a Last-In-first-Out (LIFO) issuing policy, we develop mathematical models for the following two cases:(1) opening primary shop only and (2) opening both primary shop and secondary shop. There are three decision variables, i.e., the reduced price in the secondary shop, the allowed age at the primary shop, and the order quantities at the primary shop. A solution procedure is developed based on tabu search and its validity is illustrated through a comparative study.

쇼핑몰 방문고객 수 및 방문점포 정보 기반 최적 점포위치 할당 문제

고영대 ( Young Dae Ko ),오용희 ( Yonghui Oh ) 한국경영공학회 2016 한국경영공학회지 Vol.21 No.2

There are several kinds of stores such as a clothing store, a shoe store, a jewelry store, a book store, a restaurant and so on. Those stores should be allocated at limited region of each floor of the shopping mall. It is required to make an efficient layout plan for all stores at proper location with both width and area according to the purpose or concept of that shopping mall because the number of customers who visits at certain store can be different with the store layout. There are two kinds of customers who visit there both with buying purpose and by chance. It is assumed that the number of customers who wants to visit at each store initially with buying purpose is known as constant. In addition, the customers have a chance to visit certain store which is located at their walking paths by getting an influence from attractive promotion, display of items, suggestion of clerk and so on. Therefore, the number of customers who visits at each store by chance can be regarded as a function of both the total number of customers passing by that store and the attractiveness of it. Based on these situations, a mathematical model is developed to derive an optimal store layout with the objective of maximizing the total revenue of all stores. To validate the proposed mathematical model, numerical example is designed and performed. As a result, an optimal solution about store layout at shopping mall can be generated with several insights.

공급 사슬 확장을 위한 네트워크 재설계에 관한 연구

송병덕(Byung Duk Song),오용희(Yonghui Oh) 한국전자거래학회 2012 한국전자거래학회지 Vol.17 No.4

시장 상황의 변화에 따라 상품의 효율적인 공급을 위해 기업은 한정된 예산 내에서 공급사슬을 변화시킬 필요가 있다. 또한, 경쟁의 심화로 공급 사슬 내에서의 비용절감뿐만 아니라 적절한 공급 사슬의 구성을 통해 상푸의 정시 배송 등 고객 만족도를 높이는 것은 점점 더 중요한 요소로 고려되고 있는 추세이다. 본 연구에서는 공급 사슬 확장에 따른 네트워크 재설계 문제를 다루고 있으며 이에 따른 수리 모형을 제안한다. 또한 유전 알고리즘을 이용하여 예산 제한의 변화에 따른 총 가중 거리의 변화를 계산하여 경영진의 의사결정을 도울 수 있는 방법을 모색한다. According to the environment change of market, supply chain network needs to be redesigned for efficient provision of product within the budget constraint. Also, it is desired that the customer satisfaction such as on time delivery should be considered as an important element at redesigning of supply chain network in addition to the cost reduction. In this paper redesign of supply chain network for its expansion is treated as a problem situation and a related mathematical model is suggested. Moreover, the numerical examples about the total weighted distance of the redesigned supply chain network are presented with various budget constraints by using genetic algorithm to help the managerial decision.

항공사 지상직 승무원 근무 당번표 작성문제

고영대(Young Dae Ko),오용희(Yonghui Oh) 한국경영과학회 2012 經營 科學 Vol.29 No.3

For the past several decades, personnel scheduling and rostering problem has been one of the most popular research topics in optimization area. Among the numerous applications, airline (aviation) industry has been given most attention due to the economic scale and impact. Most of the literatures about the staff scheduling problem in airline industry are dealing with the air crew, pilots and flight attendances, and the rest of the literatures are about the ground staff, by whom cleaning, maintenance, fueling of aircraft and handling luggage are done from landing to taking off. None of the literatures found by the authors are dealing with the airline ground crew. In this paper roster of airline ground crew, who is responsible for issuing boarding pass, checking baggage, etc, is introduced, formulated and solved using CPLEX. Some expressions of the mathematical formulations, which are not suitable input format of the CPLEX, were transformed. Numerical examples are presented for the validation of proposed scheduling system.

교외지역 통학버스 통합 운영 방안 연구

고영대 ( Ko Young Dae ),오용희 ( Oh Yonghui ) 한국품질경영학회 2018 품질경영학회지 Vol.46 No.4

Purpose: Generally, since the population density is lower in suburban areas, the distance to school is inevitably long. Therefore, schools in suburban areas often operate school buses to improve student welfare. However, since school buses are usually used only during going to and from school, the utilization rates are relatively low. Therefore, this study aims to establish integrated operation plan of public school bus covering all schools. Methods: It is necessary to decide which school buses will serve the specific demand node which want to go to certain school in order to design an integrated operation plan for school buses. Therefore, a mathematical model is developed for minimizing the total number of vehicles and the distance of transportation by reflecting the characteristics of school buses and students as constraints. To solve the proposed mathematical model, CPLEX, a commercial solver, is applied. Results: To validate and to confirm the proposed process, numerical example is designed with the comparison between before and after integrated operations of school buses in terms of total operation cost. The result shows that the integrated operation can lead the reduction of the number of school buses as well as the decreasing of the fuel cost. Conclusion: This study provides the quantitative method to perform the integrated operation of school buses in suburban areas. The optimal operation strategy is required because there are more complex decision-making elements considering the integrated operation. It is expected to apply this research result at real situation to expand this services based on an optimal operation.

소비자의 비윤리적 행동에 대한 방어전략

이은곤(Un-Kon Lee),박종필(Jong Pil Park),최영은(Young Eun Choi),오용희(Yonghui Oh) 한국전자거래학회 2012 한국전자거래학회지 Vol.17 No.4

소셜 네트워크 서비스(SNS) 등 정보통신 기술의 빠른 진화는 사용자들 간의 소통과 응집을 가능하게 하는 순기능과 허위 사실의 유포나 소수의 여론 독점 등 역기능 요소로써 소비자의 문제행동을 유발시킬 가능성이 있다. 소비자의 문제행동이 점차 증가하고 있으며 이에 따라 많은 사업자들이 피해를 입고 있음에도 불구하고 소비자 문제행동에 관한 선행연구들이 미미하여 체계적인 대응 전략 마련이 어려운 상황이다. 따라서 본 연구에서는 소비자 문제행동에 대한 선행연구와 구조 기반 신뢰 연구에 기반하여 소비자의 문제행동 방어전략을 모색하였다. 본 연구를 통해 소비자의 비윤리적 행위의 영역에 이르기 까지 연구의 영역을 넓힘과 동시에 실무적으로는 소비자 문제행동에 대응한 사업자 전략 및 제도적 장치 보완에 기여할 수 있을 것으로 판단한다. The evolution of the IT facilitated the social actions of the consumers by supporting social communication of the online users. At the same time it help for the consumer to post malicious comments on the Internet or to spread the unproven news for distorting the public opinion in the SNSs. Although the number of the consumer unethical behaviors and the estimated damage of the innocent companies have been increased, a few studies had investigate on this issue. Based on the Literature on the consumer unethical behaviors and the institution based trust, we had developed the defense strategies against the consumer unethical behaviors. This study would introduce the new perspective that the consumer could always not be innocent. Also, the defense strategy developed in this study could contribute to make the guideline for consumer service manual.