• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 I
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• pp.133-136
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• 2003

In this paper, we propose a multicast routing protocol for the seamless delivery of multicast data to mobile hosts through the optimal route in IP based mobile networks. The proposed multicast routing protocol is a hybrid method employing the merits of the bi-directional tunneling and the remote subscription by considering the mobility of mobile hosts. The proposed protocol satisfies the bound of end-to-end delay and supports the seamless handoff. The simulation results show that the proposed protocol has better performance in the number of multicast tree reconstruction and tunneling length and packet loss time than the previous protocols.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1618-1623
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• 2004

A holistic approach is needed in railway network modernization. What matters is that each route is developed optimally throughout its life to meet business needs - whether the answer at a given point in time is a rail repair or an redevelopment scheme. Modernization of railway network will bring railway systems up-to-date, enabling them to deliver optimal performance. As the result, the railway network modernization for revitalise the railway is based on seeking out optimum conditions for financially efficient infrastructure management, developing infrastructure fully in line with market needs and last but not least, improving railway business.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1222-1230
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• 2010

This study is about developing a transit assignment model on railway network. Current transit assignment models are mainly focused on road or urban transportation so that these models, for example, transit assignment model based on optimal strategy generates unrealistic transit assignment. Especially, since the advent of KTX, more passengers are using the transfer route containing KTX but most transit assignment models have a shortcoming that transfer is not considered or is overestimated. We present a new stochastic transit assignment model based on LOGIT considering transfer resistance.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2003년도 춘계학술발표회 논문집
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• pp.295-299
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• 2003

This study is an examination suggestion about considering circumference facilities, the development plan, prospect of traffic demanded. In addition to we study possibility about analysis of scenery and analysis of environment affection for using the virtual 3D simulation method and the GIS method.

• 대한교통학회지
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• 제20권3호
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• pp.129-147
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• 2002

본 연구에서 변동등식에 근거한 동적경로선택조건을 도출하여 동적통행배정모형을 제안한다. 동적경로선택조건은 운전자에 의해 이용된 경로, 링크 그리고 출발지의 출발시간을 고려하여 도출되며 이 조건을 동적통행배정모형으로 전환하는 과정에서 모형의 변동등식문제로 압축된다. 등식이론에 근거한 모델의 이론적 배경을 입증하기 위해 제안된 동적통행배정모형이 필요충분조건을 만족함이 증명되었다. 해법으로서 기존의 제안된 네트워크의 시간과 공간확장기법을 채택하지 않고 물리적 네트워크가 직접 알고리즘에 반영되도록 하기 위해 각 링크의 시간대별 통행량과 방출통행량을 링크진입통행으로 표현하여 시간종속 통행시간함수를 단일변수로 처리하여 대각화알고리즘에 반영하였다. 소규모 비대칭 네트워크 적용결과 사용자 동적최적경로선택조건이 만족됨을 입증하였는데 단위시간간격이 적을수록 개선된 효과를 보여준다. I-394네트워크 실험결과로서 기존의 변동부등식에 근거한 알고리즘에 비해 제안된 알고리즘이 최소한 93%이상의 컴퓨터연산 속도의 개선효과를 가져왔다. 등식이론에 근거한 모델개발의 장점으로서는 제안된 모델의 최적해의 계산시간이 전체시간의 증가에 전혀 영향을 받지 않는다는 것으로 이는 동적통행배정모형에 적용될 네트워크의 규모가 커질수록 제안된 알고리즘의 계산 효율성은 더욱 증가하는 것을 의미한다. 따라서 제안된 동적통행배정모형은 대규모 시간종속적 교통망에서 교통상황의 변화에 민감하게 반응할 수 있는 실시간첨단교통제어의 핵심기능으로서 역할수행이 기대된다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 춘계 학술대회 학술발표 논문집
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• pp.157-161
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• 2003

본 논문에서는 차량의 주행경로 최적화를 위해 강화학습 개념을 적용하고자 한다. 강화학습의 특징은 관심 대상에 대한 구체적인 지배 규칙의 정보 없이도 최적화된 행동 방식을 학습시킬 수 있는 특징이 있어서, 실제 차량의 주행경로와 같이 여러 교통정보 및 시간에 따른 변화 등에 대한 복잡한 고려가 필요한 시스템에 적합하다. 또한 학습을 위한 강화(보상, 벌칙)의 정도 및 기준을 조절해 즘으로써 다양한 최적주행경로를 제공할 수 있다. 따라서, 본 논문에서는 강화학습 알고리즘을 이용하여 다양한 최적주행경로를 제공해 주는 시스템을 구현한다.

• 상하수도학회지
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• 제12권2호
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• pp.127-139
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• 1998

The objectives of this study is at the development of the channel routing model which can be used for flood prediction. Among the routing models, the hydraulic technique of the implicit scheme in the dynamic equation is selected to route the unsteady varied flow in the open channel. The channel routing model is catchment runoff which computed by the conceptual and transfer function model. The conceptual and transfer function model can simulate the catchment runoff accurately. As a result of investigating the channel routing model, the optimal weighting factor ${\theta}$ which fixes two points between time line is chosen, and also, the optimal error tolerance which satisfies computing time and converge of solution is determined in this study.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2594-2599
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• 2011

In Korea, the HEMU-400X(High-speed Electric Multiple Unit-400km/h eXpress) has been developed since 2007 and will be operated over 400km/h in 2013. It is necessary to prepare test-bed section in Honam high-speed railroad to take the maxim running speed test for the HEMU-400X developed. In order to determine proper test-bed sections for the maximum speed of 400km/h, TPS(Train Performance Simulation) program with the data of train model, running resistance, traction power and braking capacity was used to analyze the train performances such as locations, speeds and power consumptions by times. In this study, the specifications of the HEMU-400X project and the route conditions of the Honam high-speed railroad under construction were utilized for the TPS program to determine the optimal test-bed sections for the maximum speed of 400km/h.

• 한국경영과학회지
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• 제29권4호
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• pp.175-187
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• 2004

We consider the simultaneous selection of part routes for multiple part types in Flexible Manufacturing Systems (FMSs). Using an optimization framework we investigate two alternative route assignment policies. The one, called routing mix policy in the literature, specifies the optimal proportion of each part type to be produced along its alternative routes, assuming that the proportions can be kept during execution. The other one, which we propose and call pallet allocation policy, partitions the pallets assigned to each part type among the routes. The optimization framework used is a nonlinear programming superimposed on a closed queueing network model of an FMS which produces multiple part types with distinct repeated visits to certain workstations. The objective is to maximize the weighted throughput. Our study shows that the simultaneous use of multiple routes leads to reduced bottleneck utilization, improved workload balance, and a significant increase in the FMS's weighted throughput, without any additional capital investments. Based on numerical work, we also conjecture that pallet allocation policy is more robust than routing mix policy, operationally easier to implement, and may yield higher revenues.

• 대한산업공학회지
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• 제22권3호
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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.