• 경영과학
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• 제27권3호
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• pp.15-31
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• 2010

We consider a reverse logistics network design problem for recycling. The problem consists of three stages of transportation. In the first stage products are transported from retrieval centers to disassembly centers. In the second stage disassembled modules are transported from disassembly centers to processing centers. Finally, in the third stage modules are transported from either processing centers or a supplier to a manufacturer, a recycling site, or a disposal site. The objective is to design a network which minimizes the total transportation cost. We design a cooperative coevolutionary algorithm to solve the problem. First, the problem is decomposed into three subproblems each of which corresponds to a stage of transportation. For subproblems 1 and 2, a population of chromosomes is constructed. Each chromosome in the population is coded as a permutation of integers and an algorithm which decodes a chromosome is suggested. For subproblem 3, an heuristic algorithm is utilized. Then, a performance evaluation procedure is suggested which combines the chromosomes from each of two populations and the heuristic algorithm for subproblem 3. An experiment was carried out using test problems. The experiments showed that the cooperative coevolutionary algorithm generally tends to show better performances than the previous genetic algorithm as the problem size gets larger.

• 대한교통학회지
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• 제23권5호
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• pp.65-71
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• 2005

지역유형(area type)은 물류수요의 잠재력(potential)과 밀접한 관련이 있다. 물류계획분야에서 지역유형 변수는 특히 발생모형(generation model)에서 물류유입(freight attraction)을 설명하는 모형변수로, 또한 수송수단선택모형(mode choice model)의 모형변수로 포함되는 것이 최근 선진국의 물류계획 실무분야에서 일반적인 추세이다. 하지만 지역유형은 그 동안 개념적으로 명확히 정의되지 못하였으며, 분석모형의 맥락에서 지역유형의 계량적 추정을 다룬 선행연구는 거의 없었다고 할 수 있다. 이런 이유 때문에 중/장기 물류수요예측 및 물류계획에 있어서 인구와 고용의 변화가 지역유형을 어떻게 변화시킬지에 관한 장기적인 예측을 하는 것이 어려웠다. 따라서 본 연구는 물류시설 SOC사업의 성공적 추진을 위하여 물류수요예측의 신뢰수준을 제고하는 데 있어 꼭 필요하고 시급한 연구로서 지역유형(area type)을 고려한 물류수요의 잠재력(potential)분석 방법을 제시하였다.

• 한국항공운항학회지
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• 제30권4호
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• pp.199-206
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• 2022

제주공항은 슬롯 증대사업을 통한 정시성 개선 노력에도 불구하고 항공 교통량의 확대에 따른 혼잡도의 증가가 지속되고 있다. 제주공항 혼잡도의 근본적인 해소를 위해서 추진되고 있는 신공항 건설이 여러 가지 사유로 지연되고 있으며, 실제 건설계획이 확정되더라도 정상적인 공항 운영까지 상당 기간의 시간이 소요될 것으로 예상된다. 따라서 제주 신공항 건설이라는 대규모 신규 투자와는 별개로 신공항 개항 전, 기존 제주공항을 운영하면서 혼잡도를 해소할 수 있는 중단기적 대안을 마련할 필요가 있다. 이에 국토교통부와 한국공항공사는 제주공항에 소형기보다는 최대이륙중량 100톤 이상의 대형항공기(통상 270석 이상 공급) 투입을 유도하는 착륙료 감면 조치를 시행하였으며, 최초 착륙료 10% 감면에서 추가 활성화를 위하여 착륙료 20% 감면으로 확대하여 운영 중이다. 항공사는 착륙료 감면 비율 상향을 통해 대형기 투입에 따른 실질적인 비용이 절감된다면 상기 정책에 적극 동참하게 될 것이다. 본 논문에서는 제주공항에서 실시 중인 착륙료 감면율 확대 조정이 항공사의 대형기 배정에 미치는 효과를 분석하여 정책의 실효성을 고찰하였으며 이에 따른 개선책을 제시하였다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 추계학술대회 논문집(제1권)
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• pp.283-291
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• 2006

최근 남북한 경제교류 증대, 개성공단의 급속한 발전 등에 따라 남북한 물류도 급속히 증가하고 있어 기존의 육상 수송뿐만이 아니라 다양한 형태의 수송로 확보가 필요한 실정이다. 한편 유럽 및 미국 등에서는 항만 및 적하역 시설의 이용이 용이하며 초기 투자비용이 저렴한 바아지시스템이 화물 수송에 널리 이용되고 있다. 본 연구에서는 먼저 바아지시스템을 활용한 인천-개성(공단) 항로의 사회적, 경제적 타당성에 대하여 검토한다. 또한 인천-개성(공단)간 바아지 후보 항로를 제시하고 시험운항, 실해역 조사 및 현장 답사 등을 통하여 바아지 운항에 대한 기술적 타당성을 검토한다. 마지막으로 인천-개성(공단)간의 최적 항로와 바아지시스템을 제안한다.

• 한국경영과학회지
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• 제24권3호
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• pp.109-123
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• 1999

Fleet sizing and empty equipment redistribution are two of the most critical problems in managing a fleet of equipment over a transportation network. Where the demand pattern followed the compound Poisson process(CPP) which can be generated one or more at a time under homogeneous Poisson process(HPP), this paper presented a mathematical model to determine control parameters of a decentralized distribution policy and fleet size in case of the pure hub-and-spoke system, a popular form of a logistics system. and validated this model by simulation. That is, where the number of demanded equipments followed geometric and binomial distributions, respectively, cost models on the pure hub-and-spoke logistics system with deterministic trans-portation times, which could be solved analytically, were established and analyzed. We also compared the deterministic case with stochastic one that the transportation time follows some probability distributions.

• 유통과학연구
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• 제13권10호
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• pp.123-133
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• 2015

Purpose - The Korean government has devised intermodal transportation policies and granted subsidies to shippers and logistics companies that made a conversion of transportation means through the policies. This provides support by expanding the complex uniform railroad transportation and overhauling the deteriorated railroad facilities. As for 2013, however, the freight transportation percentage of railroad was 4.5% in tons and 8.5% in ton kilometers. Meanwhile, since the 1990s, developed countries such as the U.S. and Europe have been trying to expand intermodal freight transport with a legal and institutional support to build a logistics system corresponding with social and economic environmental changes. In this study, I set out to examine the effects of the intermodal freight transport policies in the EU and the U.S., and to explore the direction of setting up a rail intermodal transport system in South Korea. Research design, data, and methodology - The paper used a qualitative research methodology through the literature review. First, was an overview of Intermodal transportation in the EU, U.S. and UN. Second, it describes the development of transport in Europe and the U.S. with particular emphasis on intermodal freight transport. Third, it explores the direction of setting up a intermodal freight transport in South Korea. The last section contains concluding remarks. Results - As for the EU, it has been promoting integration between transport and intermodal logistics network designs while utilizing ITS or ICT and supports for rail freight intermodal by giving reduction to a facilities fee or subsidizing for rail freight in order to minimize the cost of external due to freight transport. On the other hand, as for the U.S., it has been made up of an industrial-led operating project and has been promoting it to improve accessibility between intermodal hubs and cargo terminals through intermodal corridor program, and an intermodal cargo hub access corridor projects, etc. Moreover, it has tried to construct intermodal transport system using ITS or ICT and to remove Barrier. As a result, in these countries, the proportion of intermodal freight transport is going to be the second significant transport compared with rail and maritime transport. An Effective rail intermodal transport system is needed in South Korea, as seen in the case of these countries. In order to achieve this object, the following points are required to establish radical infrastructure policy; diversify investment financing measures taken under public-private partnerships, legal responsibilities, improvement of utilization of existing facilities to connect the railway terminal and truck terminal, and enhancement service competitiveness through providing cargo tracking and security information that combines the ITS and ICT. Conclusions - This study will be used as a basis for policy and support for intermodal freight transport in South Korea. In the future, it is also necessary to examine from the perspective of the shipper companies using the rail intermodal transport, ie, recognition of shipper, needed institutional supports, and transportation demand forecasting and cost-effective analysis of the railway infrastructure systems improvement.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2002년도 춘계공동학술대회
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• pp.171-178
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• 2002

At the present time, container transportation plays a key role in the international logistics and the efforts to increase the productivity of container logistics become essential for Korean trucking companies to survive in the domestic as well as global competition. This study suggests an approach for determining fleet size for container road transportation with dynamic demand. Usually the vehicles operated by the transportation trucking companies in Korea can be classified into three types depending on the ways how their expenses occur; company-owned truck, mandated truck which is owned by outsider who entrust the company with its operation, and rented vehicle (outsourcing). Armually the trucking companies should decide how many company-owned and mandated trucks will be operated considering vehicle types and the transportation demands. With the forecasted monthly data for the volume of containers to be transported a year, a heuristic algorithm using tabu search is developed to determine the number of company-owned trucks, mandated trucks, and rented trucks in order to minimize the expected annual operating cost The idea of the algorithm is based on both the aggregate production planning (APP) and the pickup-and-delivery problem (PDP). Finally the algorithm is tested for the problem how the trucking company determines the fleet size for transporting containers.

• 통상정보연구
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• 제11권1호
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• pp.3-25
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• 2009

These days international trade has been converting to e-Trade formation. At this point, Korea has been striving for the trade facilitation; reducing logistics cost and improving foreign competitiveness by computerization operations of the maritime transportation that logistics and customs clearance are involved. However, due to the substantial characteristic of logistics service, the necessity of flexible and various logistics service development using internet has been strongly suggested. In particular, the logistics service which could share documents related to international physical movement between shippers and logistics organization. In this regard, this study carried out interview to explore the problems of physical distribution service and to suggest development direction of e-logistics service. The reason why this survey carried out is that most of users want more effective e-logistic service that could diminish successively real expense decrease. After analysis of survey results, this paper presents the basic development direction and emphasis development subjects. Therefore, the basic direction is presented from four viewpoints; customer-oriented approach, service-oriented approach, total approach and step-by-step implementation. Furthermore six development subjects; web-based standard module development for small and medium forwarders, development of standard logistics ERP system, collaboration model between KTNET and KLNET, system improvement for real users, on-demand system building for SMEs and connection with legacy system have been required.

• 대한산업공학회지
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• 제35권1호
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• pp.1-14
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• 2009

The efficiency of transportation requests fulfillment can be increased through extending the problem of vehicle routing and scheduling by the possibility of subcontracting a part of the requests to external carriers. This problem extension transforms the usual vehicle routing and scheduling problems to the more general integrated operational transportation problems. In this contribution, we analyze the motivation, the chances, the realization, and the challenges of the integrated operational planning and report on experiments for extending the plain Vehicle Routing Problem to a corresponding problem combining vehicle routing and request forwarding by means of different sub-contraction types. The extended problem is formalized as a mixed integer linear programming model and solved by a commercial mathematical programming solver. The computational results show tremendous costs savings even for small problem instances by allowing subcontracting. Additionally, the performed experiments for the operational transportation planning are used for an analysis of the decision on the optimal fleet size for own vehicles and regularly hired vehicles.

• 한국항해항만학회지
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• 제27권3호
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• pp.289-295
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• 2003

The international oil majors have been reducing the size of their own oil tanker fleet since early 1980s. Like international oil majors, the Korean refineries are becoming more dependent on tanker chartering rather than tanker ownership for their oil transportation since the 1990s. They also prefer spot charter to time charter and this kind of trend has continued up to now. Consequently, this paper attempted to find the factors influencing changes in tanker fleet composition. To attain the object of the paper, an empirical study is adopted using the ten decision-making factors derived from preceeding studies. The findings are that MARPOL and OPA 90, and transportation costs are the most important factors influencing an oil tanker fleet composition.