• Journal of Korean Society of Transportation
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• v.19 no.2
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• pp.61-72
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• 2001

기존의 링크교통량으로부터 OD추정모형은 기존 OD에 대한 추정의 종속성이 커, 기존 OD나 관측링크교통량의 오차에 따라 추정결과가 일관적이지 않은 문제점을 가지고 있다. 또한 관측링크교통량의 정확도가 중요함에도 불구하고 차종구분 없이 링크교통량을 이용하여 정보의 손실을 초래하였고 결과적으로 OD 추정력을 저하시켰다. 그렇지만 다차종 링크교통량으로부터 다차종 OD를 구하는 연구는 거의 없었으며, 그 추정결과가 단일차종에 대한 추정결과와 어떻게 다른지에 대한 연구도 전무하였다. 본 연구의 목적은 기존의 OD 추정모형이 기존 OD에 대해 종속성을 가지며 차종구분 없이 모형을 구성함으로써 추정력의 저하를 초래하였음을 밝히고, 이에 대한 대안으로 종속성 문제를 완화하고 차종구분을 통해 OD 추정모형의 추정력을 증진시키자 하는 것이다. 이를 위해 유전알고리즘을 이용한 다차종 OD행렬 추정모형(GAMUC)을 구축하고, 이를 기존의 바이레벨 모형의 IEA 알고리즘 및 다차종으로 확장한 모형(IEAMUC)과 게임이론측면에서 검토하였으며, 사례네트워크에 대해 각 기법을 비교하였다. 본 연구는 유전알고리즘을 이용한 OD 추정기법을 축도로에 적용한 임용택 등(2000)과 이를 네트워크로 확장한 백승걸 등(2000)의 연구를 다차종으로 확장한 것이다. 사례분석 결과 기존 OD의 오차변화나 관측링크교통량의 오차변화 등에 있어 GAMUC가 IEA나 IEAMUC보다 추정력이 양호하여, 실제 OD를 알 수 없는 도시부 네트워크에서 GAMUC 모형의 적용력이 우수하였다. 또한 차종을 구분하지 않은 기존 모형은 실제 OD와는 전혀 다른 OD 구조를 도출할 수 있음을 보였으며, 단일 차종을 여러 차종으로 구분하여 OD를 추정하는 것이 더 양호한 추정력을 확보하는 것으로 나타났다.

• Journal of Korean Society of Transportation
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• v.29 no.5
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• pp.79-89
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• 2011

Though many studies regarding roundabout have been recently conducted, most of them have focused on operational aspect. Moreover, majority of the previous researches analyzes operational effects of single roundabout, but seldom investigate the effects of multi-roundabouts constructed on road networks. In this study, we seek ways to construct multiple roundabouts on road network maximizing their operational effects. The analysis investigate influence of both adjacent signalized and unsignalized intersections as well as influence of the distance from those intersections to roundabouts. The results show that the optimal distance between two adjacent intersections were calculated to be 150m, and any two intersections located within 150m apart influence each other thus imposing operational restrictions on each other. In addition, those results are confirmed using simulation analysis conducted on the real urban network in Nonheon regional area, Incheon City.

• Journal of Korean Society of Transportation
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• v.27 no.1
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• pp.27-34
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• 2009

The operational effect of traffic signal control improvement was evaluated using the Two-Fluid Model. The parameters engaged in the Two-Fluid Model becomes food indicators to measure the quality of traffic flow due to the improvement of traffic signal operation. A series of experiment were conduced for the 31 signalized intersections in Uijeongbu City. To estimate the parameters in the Two-Fluid Model the trajectory informations of individual vehicles were collected using the CORSIM and Run Time Extension. The test results showed 35 percent decrease of average minimum trip time per unit distance. One of the parameters in the Two-Fluid Model is a measure of the resistance of the network to the degraded operation with the increased demand. The test result showed 28 percent decrease of this parameter. In spite of the simulation results of the arterial flow, it was concluded that the Two-Fluid Model is useful tool to evaluate the improvement of the traffic signal control system from the macroscopic aspect.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.1
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• pp.70-85
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• 2021

Deep learning methodology, which has been actively studied in recent years, has improved the performance of artificial intelligence. Accordingly, systems utilizing deep learning have been proposed in various industries. In traffic systems, spatio-temporal graph modeling using GNN was found to be effective in predicting traffic speed. Still, it has a disadvantage that the model is trained inefficiently due to the memory bottleneck. Therefore, in this study, the road network is clustered through the graph clustering algorithm to reduce memory bottlenecks and simultaneously achieve superior performance. In order to verify the proposed method, the similarity of road speed distribution was measured using Jensen-Shannon divergence based on the analysis result of Incheon UTIC data. Then, the road network was clustered by spectrum clustering based on the measured similarity. As a result of the experiments, it was found that when the road network was divided into seven networks, the memory bottleneck was alleviated while recording the best performance compared to the baselines with MAE of 5.52km/h.

• Journal of Korean Society of Transportation
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• v.26 no.5
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• pp.185-194
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• 2008

The objective of this paper is to design the dynamic route guidance system(DRGS) and develop an ant algorithm based on routing mechanism for finding the multiple shortest paths within limited time in real traffic network. The proposed ant algorithm finds a collection of paths between source and destination considering turn-restrictions, U-turn, and P-turn until an acceptable solution is reached. This method can consider traffic constraints easily comparing to the conventional shortest paths algorithms.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.05a
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• pp.106-106
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• 2001

네트웍의 용량의 개념이 없는 미세한 교통혼잡 도구로서 Microscopic시뮬레이션 모형인 Paramics가 소개된다. 모형의 기본구조가 설명되고, 특히 응용사례로서 서울시 교통관리 시스템을 설치함에 있어서 대안의 평가에 따른 제반 결과의 척도를 이끌어 내는 절차가 소개되었고, 아울러 결과가 분석되어 제시되었다. 이는 미시적 교통 시뮬레이션을 위한 고성능의 소프트웨어로서 각 차량들은 상세한 속성들을 가지고, ITS와 운전자와의 인터페이스를 모델링 할 뿐만 아니라 정확한 교통류, 대중교통 시간, 혼잡정보를 시뮬레이션 할 수 있는 장점이 있는바 적용 분야로서 여기까지가 있으나 혼잡이 있는 도로 네트워크 및 일반도로 네트워크와 ITS 인프라의 존재상황에서 제반 모델링이 가능한바 이를 통한 도시고속도로 관리시스템의 효과를 분석하였다. 신호의 영향, 첨단신호제어, 램프 미터링, 루프 검지기, 다양한 속도 표지, VMS 정보전략 등의 기능을 소개하고 금번 서울시의 사례를 통한 모형의 장단점을 보고한다. 아울러 이 시뮬레이션 모형의 한계도 함께 지적되었다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.901-908
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• 2010

There are many kinds of networks in vehicle for their purposes. In-vehicle networks, however, are not unified to single network. The networks are composed of several local networks because of communication speed, cost and efficiency. Because the complexity of network design for communication increases, local networks need a framework for interworking between heterogeneous networks. In this paper, a framework interworking between in-vehicle networks for ITS(Intelligent Transportation System) is proposed and implemented. The proposed framework consists of a compatible protocol, message conversion module, message transceiver module and message analysis module. The results obtained by implementation show that the framework efficiently supports the communication of information between heterogeneous in-vehicle networks.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.1
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• pp.63-71
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• 2019

The two-fluid model proposed by Herman and Prigogine is useful for analyzing macroscopic traffic flow in a network. The two-fluid model is used for analyzing a network through the relationship between the ratio of stopped vehicles and the average moving speed of the network, and the two-fluid model has also been applied in the urban transportation network where many signalized or unsignalized intersections existed. In general, the average travel speed and moving speed of a network decrease, and the ratio of stopped vehicles and low speed vehicles in network increase as the traffic demand increases. This study proposed the two-fluid model considering congested and uncongested traffic situations. The critical velocity and the weight factor for congested situation are calibrated by minimizing the root mean square error (RMSE). The critical speed of the Seoul network was about 34 kph, and the weight factor of the congestion on the network was about 0.61. In the proposed model, $R^2$ increased from 0.78 to 0.99 when compared to the existing model, suggesting that the proposed model can be applied in evaluating network performances or traffic signal operations.

• Proceedings of the KOR-KST Conference
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• 1994.10b
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• pp.5-23
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• 1994

• Transportation Technology and Policy
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• v.4 no.4
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• pp.31-58
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• 2007