• IE interfaces
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• v.11 no.1
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• pp.183-190
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• 1998

This paper is concerned with the bicriteria vehicle routing problems with time window constraints(BVRPTW). The BVRPTW is to determine the most favorable vehicle routes that minimize the total vehicle travel time and the total customer wait time which are, more often than not, conflicting. We construct a linear goal programming (GP) model for the BVRPTW and propose a heuristic algorithm to relieve a computational burden inherent to the application of the GP model. The heuristic algorithm consists of a parallel insertion method for clustering and a sequential linear goal programming procedure for routing. The results of computational experiments showed that the proposed algorithm finds successfully more favorable solutions than the Potvin an Rousseau's method that is known as a very good heuristic for the VRPs with time window constraints, through the change of target values and the decision maker's goal priority structure.

• Journal of the Korean Operations Research and Management Science Society
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• v.19 no.1
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• pp.153-168
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• 1994

This paper is concerned with the development of tree-search algorithm for the exact solution to the vehicle problem (VRP), where set of vehicles of known capacity based at depot, have to be routed in order to supply customers with known requirements. When is required is to design routes, so that the total cost (i. e. total route length or time duration, ect.) is minimized. For obtianing the exact solution, the most important factors are the value of bound and branching strategy. Using the bound based on with bound ascent procedures from subgradient and state-space ascents, the incorporation of bounds into tree search algorithm to solve the problem is shown. Computational results of the corresponding algorithm show that VRPs with up to 40 customers can be solved optimally with this algorithm.

• Proceedings of the KOR-KST Conference
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• 1998.10b
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• pp.507-507
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• 1998

화물 수송은 상품의 생산과 소비에 직결되어 있으며 원활한 화물 수송이 경제에 미치는 영향이 크므로 그 중요성이 날로 증대되고 있다. 우리 나라는 그 동인 지속적 경제 성장으로 인한 경제 규모가 확대되면서 화물 수송에 대한 수요가 급격히 증가하였다. 이러한 화물 수송 수요의 증가 추세에 비해 물류 단지의 확충에 위한 적절한 투자 및 정책 등이 결여되어 왔다. 그러므로, 경제 및 산업발전에 중요한 역할을 담당하고 있는 물류 단지를 파악하고 물류 단지 입지 결정 모형을 개발하고, 이 모형을 토대로 적정 입지를 결정하고자 한다. 물류 단지 입지에 관한 문제의 주요 관심 대상은 수송비용을 최소화하면서, 원하는 목적지까지의 빠른 수·배송을 이루어지게 하는 효율적 수송 입지 단지를 찾는데 있다. 따라서 본 연구에서는 물류 단지의 적정 위치 결정을 위하여 혼합 정수 모형을 이용해서 수송비용과 차량 경로를 고려한 수학적 모형을 개발하고자 한다. 개발된 모형을 공로부문의 수송을 중심으로 경기도 지역의 여러 물류 단지 후보 지역에 적용하고 적정 물류 단지를 찾고자 한다.

• Journal of the military operations research society of Korea
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• v.30 no.2
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• pp.81-95
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• 2004

This paper presents optimal solutions for the following two problems ; (1) The vehicle routing problem with deadline considering homeward-route transport requirement, (2) The problem of (1) with relaxed constraint that the vehicle cannot visit the depot during the trip. That is, for the second problem, vehicle can visit the depot several times during the trip. The formulation and optimal solution we obtained outperform the existing ones proposed by other researchers in the sense of time and total distance traveled and the results can be applicable to short-haul local transport.

• Korean Management Science Review
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• v.24 no.2
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• pp.43-56
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• 2007

VRP(Vehicle Routing Problem) is studied in this paper, where two different kinds of missions are to be completed. The objective is to minimize the total vehicle operating distance. A mixed integer programming formulation and a heuristic algorithm for a practical use are suggested. A heuristic algorithm consists of three phases such as clustering, constructing routes, and adjustment. In the first phase, customers are clustered so that the supply nodes are grouped with demand nodes to be served by the same vehicle. Vehicle routes are generated within the cluster in the second phase. Clusters and routes are adjusted in the third phase using the UF (unfitness) rule designed to determine the customers and the routes to be moved properly. It is shown that the suggested heuristic algorithm yields good performances within a relatively short computational time through computational experiment.

• 한국IT서비스학회:학술대회논문집
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• 2010.05a
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• pp.68-73
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• 2010

도심내 지속적인 차량증가에 따라 도시의 주차문제는 운전자에게 있어 과거부터 현재까지 여전히 불편함을 주고 있다. 이에 유비쿼터스 기술을 이용한 주차시스템이 활발히 연구중이며, 센서를 이용한 새로운 형태의 주차장이 생겨나고 있다. 따라서, 본 논문에서는 국내 사례 및 선행연구의 검토를 통해 시사점을 도출하였고, 더욱 더 발전된 모바일을 기반으로 한 유비쿼터스 기술을 적극 활용하여 능동적이고 개인 맞춤형의 통합 주차서비스가 가능한 지능형 u-Parking시스템을 제안하였으며, 개별 운영관리의 비효율성을 u-City의 통합운영센터와의 연계를 통하여 효율적 방법을 제시하였다. 또한 주차장 스마트 검색, 인터넷 주차장 예약제, 경로연계 맞춤형 정보제공 등 u-서비스 비즈니스 모델 제시를 통하여 효율성과 경제성을 확보방안을 마련하였다.

• Journal of the Korea Safety Management & Science
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• v.10 no.1
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• pp.145-153
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• 2008

The vehicle routing problem determines each vehicle routes to find the transportation costs, subject to meeting the customer demands of all delivery points in geography. Vehicle routing problem is known to be NP-hard, and it needs a lot of computing time to get the optimal solution, so that heuristics are more frequently developed than optimal algorithms. This study aims to develop a heuristic method which combines guided local search with a tabu search in order to minimize the transportation costs for the vehicle routing assignment and uses ILOG programming library to solve. The computational tests were performed using the benchmark problems. And computational experiments on these instances show that the proposed heuristic yields better results than the simple tabu search does.

• Journal of Korean Institute of Industrial Engineers
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• v.22 no.3
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• pp.325-336
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• 1996

This study is concerned with developing a heuristic for the vehicle routing problem(VRP) which determines each vehicle route in order to minimize the transportation costs, subject to meeting the demands of all delivery points. VRP is known 10 be NP-hard, and it needs a lot of computing time to get the optimal solution, so that heuristic are more frequently developed than optimal algorithms. This study aims to develop a heuristic which can give a good solution in comparatively brief time. Finally, the computational tests were performed using the benchmark problems and the proposed heuristic is compared with the other existing algorithms. The result of computational tests shows that the proposed heuristic gives good solutions, in much shorter time, which are not 1% more expensive than the best known solutions, which are same as the best known solutions in the previous researches.

• IE interfaces
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• v.22 no.4
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• pp.359-367
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• 2009

The vehicle travel time between the demand points in downtown area is greatly influenced by complex road condition and traffic situation that change real time to various external environments. Most of research in the vehicle routing problems compose vehicle routes only considering travel distance and average vehicle speed between the demand points, however did not consider dynamic external environments such as traffic situation by service time zones. A realistic vehicle routing problem which considers traffic situation of smooth, delaying, and stagnating by three service time zones such as going to work, afternoon, and going home was suggested in this study. A mathematical programming model was suggested and it gives an optimal solution when using ILOG CPLEX. A hybrid genetic algorithm was also suggested to chooses a vehicle route considering traffic situation to minimize the total travel time. By comparing the result considering the traffic situation, the suggested algorithm gives better solution than existing algorithms.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.82-83
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• 2013

친환경 차량에 대한 관심이 급증함에 따라 고효율 운전이 가능한 하이브리드 전기자동차(이하 HEV)에 대한 관심이 급증하고 있다. HEV에는 효율이 높고 단위 체적당 토크가 큰 고성능 전동기가 적용되고 있으며 자동차에 적용되는 특수성으로 인해 고속영역에서의 안정된 출력 특성이 요구되고 있다. 회전계자부에 권선을 적용한 계자권선형 동기전동기는 영구자석형 전동기에 비해 효율이 다소 감소하는 단점이 있으나, 공극 자속을 임의로 제어할 수 있기 때문에 저속영역부터 10,000rpm 이상의 고속영역까지 탁월한 가변속 능력을 발휘하는 장점이 있으며, 저용량 HEV에 매우 적합한 특성을 지니고 있다. 그러나, 일반적인 영구자석형 동기전동기와는 다르게 d,q축 전류 뿐만 아니라 자속성분 전류까지 제어 대상에 포함되므로 제어계가 복잡해지는 문제가 발생한다. 본 논문에서는 HEV용 계자 권선형 동기전동기의 단위 전류당 최대토크 제어(MTPA)에 대하여 연구를 진행하였으며, 전압-전압제한 하에서 이론적으로 발생 가능한 최대토크 능력 커브를 기반으로 실제 시스템에서 쉽게 구현할 수 있는 약계자 제어 알고리즘을 제안한다.