• 한국콘텐츠학회논문지
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• 제8권3호
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• pp.47-54
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• 2008

도로 기반 시설의 도움 없이 지능형 교통 시스템을 실현하기 위한 차량 간 통신(Inter-Vehicle Communication)에 대한 관심이 증가하고 있다. 차량 간 통신은 고정된 인프라 없이 차량간에 실시간 정보를 교환할 수 있게 해준다. 차량 간 통신 시스템은 정보를 전송하기 위해 멀티 홉 브로드캐스트 방식을 사용한다. 본 논문에서는 차량 간 통신을 위한 위치 정보 기반의 AODV 라우팅 프로토콜을 제안한다. 제안하는 AODV 라우팅 프로토콜은 위치 정보를 갖는 Hello 패킷을 전송하여 노드간 거리를 계산한다. 그런 다음 각 노드의 거리테이블을 이용하여 신속한 경로 복구를 수행한다. 제안하는 AODV 라우팅 프로토콜의 성능은 퀄넷(Qualnet) 버전 3.8 시뮬레이터를 사용하여 기존의 AODV 라우팅 프로토콜과 비교하였다.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제2권6호
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• pp.253-256
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• 2013

VANET에서는 차량 안전 관련 정보가 차량들 간에 안정적으로 전달될 수 있도록 해주는 라우팅 프로토콜이 요구된다. 본 논문에서는 도시기반의 VANET 환경에서 차량 간의 빠르고 안정적인 통신을 위하여 차량 밀도 정보를 이용한 라우팅 기법을 제안한다. 제안 기법에서 각 차량은 비콘 메시지와 도로 정보을 이용해서 도로의 차량 밀도를 계산한다. 차량들은 이 정보를 이용해서 패킷을 전송할 안정적인 경로를 설정한다. NS-2 시뮬레이션을 통해 제안 기법과 GPSR의 성능을 비교했으며, 그 결과 제안 기법이 패킷 전송 성공률 측면에서 우수한 성능을 보임을 알 수 있었다.

• 대한산업공학회지
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• 제35권2호
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• pp.150-159
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• 2009

The heterogeneous fleet vehicle routing problem(HVRP) is a variant of the classical vehicle routing problem in which customers are served by a heterogeneous fleet of vehicles with various capacities, fixed costs and variable costs. We propose a new conceptual HVRPCR(HVRP with customer restriction) model including additional customer restrictions in HVRP. In this paper, we develop hybrid particle swarm optimization(HPSO) algorithm with 2-opt and node exchange technique for HVRP. The solution representation is a n-dimensional particle for HVRP with N customers. The decoding method for this representation starts with the transformation of particle into a priority list of customer to enter route and limit of vehicle to serve each customer. The vehicle routes are then constructed based on the customer priority list and limit of vehicle to serve. The proposed algorithm is tested using 8 benchmark problems and it consistently produces high-quality solutions, including new best solutions. The numerical results show that the proposed algorithm is robust and efficient.

• 산업공학
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• 제19권3호
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• pp.202-213
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• 2006

In this paper, we develop a planning system for the routing and scheduling of vehicles in pickup and delivery service such as door-to-door parcel service. Efficient routing and scheduling of vehicles is very important in pickup and delivery service. The routing and scheduling problem is a variation of vehicle routing problem which has various realistic constraints. We develop a heuristic algorithm based on tabu search to solve the routing and scheduling problem. We develop a routing and scheduling system installed the algorithm as a planning engine. The system manage the basic data and uses GIS data to make a realistic route plan.

• 한국통신학회논문지
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• 제35권9A호
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• pp.882-888
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• 2010

Vehicular Ad-Hoc Networks (VANETs) using inter-vehicle communication can potentially enhance traffic safety and facilitate many vehicular applications. Therefore, this paper proposes an inter-vehicle routing protocol called Junction-Assisted Routing (JAR) that uses fixed junction nodes to create the routing paths for VANETs in city environments. JAR is a proactive routing protocol that uses the Expected Transmission Count (ETC) for the road segment between two neighbor junctions as the routing paths between junction nodes. Simulation results showed that the proposed JAR protocol could outperform existing routing protocols in terms of the packet delivery ratio and average packet delay.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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• pp.52-58
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• 2005

In this paper, we address a real-world periodic vehicle routing problem with time windows (PVRPTW). In addition to the general requirements of single-day vehicle routing problem, each stop has required number of visits within a cycle period in PVRPTW. Thus, we need to determine optimized days of visit for each stop with consideration of the cycle-period days together. The problem also requires consistent vehicle assignment to the stops. We developed a clustering based 3-phase approach for this problem: 1) stop-route assignment, 2) stop-day assignment, and 3) stop sequencing within a single-day route. Using the approach, we could reduce the number of routes and improve the routing efficiency for several real-world problems.

• 유통과학연구
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• 제10권12호
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• pp.19-24
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• 2012

Purpose - This paper discusses the heterogeneous fixed fleet vehicle routing problem with pick-up and delivery (HFFVRPPD), for vehicles with different capacities, fixed costs, and travel costs. Research Design, data, methodology - This paper made nine assumptions for establishing a mathematical model to describe HFFVRPPD. It established a practical mathematical model, and because of the non-deterministic polynomial-time hard (NP-hard), improved the traditional simulated annealing algorithm and tested a new algorithm using a certain scale model. Result - We calculated the minimum cost of the heterogeneous fixed fleet vehicle routing problem (HFFVRP) with a single task and, on comparing the results with the actual HFFVRP for the single task alone, observed that the total cost of HFFVRPPD reduced significantly by 46.7%. The results showed that the new algorithm provides better solutions and stability. Conclusions - This paper, by comparing the HFFVRP and HFFVRPPD results, highlights certain advantages of using HFFVRPPD in physical distribution enterprises, such as saving distribution vehicles, reducing logistics cost, and raising economic benefits.

• 한국항해항만학회지
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• 제33권2호
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• pp.143-151
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• 2009

The field of vehicle routing is currently growing rapidly because of many actual applications in truckload and less than truckload trucking, courier services, door to door services, and many other problems that generally hinder the optimization of transportation costs in a logistics network. The rapidly increasing number of customers in such a network has caused problems such as difficulty in cost optimization in terms of getting a global optimum solution in an acceptable time. Fast algorithms are needed to find sufficient solutions in a limited time that can be used for real time scheduling. In this paper, the nearest L-method (NLNM) is proposed to obtain a vehicle routing solution. String neighbors of different lengths were chosen, tested and compared. The applied de crossing procedure is meant to solve the routes by NLNM by giving a better solution and shorter computation time than that of NLNM with long string neighbors.

• 산업공학
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• 제20권2호
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• pp.204-215
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• 2007

This paper addresses vehicle routing planning in freight container transportation systems where a number of loaded containers are to be delivered to their destination places. The system under consideration is static in that all transportation requirements are predetermined at the beginning of a planning horizon. A two-phased procedure is presented for freight container transportation. In the first phase, the optimal model is presented to determine optimal total time to perform given transportation requirements and the minimum of number of vehicles required. Based on the results from the optimal model, in the second phase, ASA(Accelerated Simulated Annealing) algorithm is presented to perform all transportation requirements with the least number of vehicles by improving initial vehicle routing planning constructed by greedy method. It is found that ASA algorithm has an excellent global searching ability through various experiments in comparison with existing methods.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2022년도 제66차 하계학술대회논문집 30권2호
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• pp.705-707
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• 2022

본 연구에서는 기존 차량 경로 문제(Vehicle Routing Problem)의 범위를 확장시켜 일반화된 차량 경로문제(Generalized Vehicle Routing Problem)를 제시하고, 이 문제를 해결하기 위한 강화학습 모델을 제안한다. 기존의 차량 경로 문제는 depot에서 각 node(또는 각 node에서 depot)의 단방향만 존재해 제한된 문제만을 해결할 수 있었다. 이 한계점을 극복하기 위해 depot을 제외한 모든 node가 서로 연결된 형태의 일반화된 차량 경로 문제를 정의하고 이를 해결하고자 한다. 차량 경로 문제는 NP-hard 문제로 최근에는 강화학습을 이용해 이를 해결하고자 하는 모델이 연구되고 있다. 본 연구에서는 새로 정의한 일반화된 차량 경로 문제를 해결하기 위한 강화학습 모델을 제안한다.