• Journal of Korean Society of Transportation
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• v.29 no.4
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• pp.113-123
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• 2011

Traffic signal control is one of the most cost-effective means of improving urban mobility. With the recent progress of ITS (Intelligent Transportation System) and the installation of the real time traffic control systems, traffic signal control is conducted in online and real time. Normally, time-of-day (TOD) signal control is used with the system, but no definite methodology has yet been available for efficient TOD signal planing designing. Such method and process are in need to optimize the traffic signal timing plan. This paper proposes the optimization of TOD signal timings on arterials. The effects of the signal timings from the proposed method were assessed in the field. The proposed includes the methods determining the separation of the TOD break points and the TOD intervals. Those were tested on an arterial consisting of ten coordinated signalized intersections. It was found from the test results that the proposed TOD signal timing plans outperformed the previous signal timings.

• Journal of Korean Society of Transportation
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• v.20 no.5
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• pp.193-206
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• 2002

A signal optimization model is proposed by applying the Cell-Transmission Model(CTM) as an embedded traffic flow model to estimate a system-optimal signal timing plan in a transportation network composed of signalized intersections. Beyond the existing signal-optimization models, the CTM provides appropriate theoretical and practical backgrounds to simulate oversaturation phenomena such as shockwave, queue length, and spillback. The model is formulated on the Mixed-Integer Programming(MIP) theory. The proposed model implies a system-optimal in a sense that traffic demand and signal system cooperate to minimize the traffic network cost: the demand departing from origins through route choice behavior until arriving at destinations and the signal system by calculating optimal signal timings considering the movement of these demand. The potential of model's practical application is demonstrated through a comparison study of two signal control strategies: optimal and fixed signal controls.

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.54-54
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• 2003

위성이 우주 공간에서 통신, 관측 등의 임무를 제대로 수행할 수 있도록 지상에서 원격으로 추적, 제어, 감시 등의 관제가 필요하며, 본 연구에서는 과학 위성 1호 관제 시스템 프로그램에 대하여 살펴본다. 과학 위성 1호 관제 시스템은 한번에 운용할 수 있는 시간이 짧은 특성을 고려한, 통신 신호 처리시스템, 위성 제어 시스템, 위성 임무 계획 시스템으로 구성되었다. 통신 신호 처리 시스템은 위성과 지상국 간의 무성 링크와 신호 처리를 위한 시스템이고, 위성 제어 시스템은 위성의 건강 상태를 감시하고, 위성의 임무 수행을 위한 명령을 송수신하는 시스템이고, 임무 계획 시스템은 사용자의 요구를 실제 위성 운영 계획 또는 탑재체 운용을 계획하는 시스템이다. 위성의 임무는 임무 계획 시스템을 통해서 철저히 분석을 통해서 생성되고, 이렇게 생성된 임무는 위성 제어 시스템에서 제어 명령으로 변환되며, 이러한 제어 명령은 통신 신호 처리 시스템을 거쳐 위성으로 전달된다. 특히, 짧은 운용 시간을 고려하여 과학위성 1호 관제 시스템 프로그램에서는 위성 제어 시스템은 위성의 이상 상태 여부를 신속히 파악하고, 정확하고 신속하게 판단하고 복구할 수 있도록 구현하였다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.1
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• pp.81-92
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• 2023

Traffic state classification is crucial for time-of-day (TOD) traffic signal control. This paper proposed a traffic state classification technique applying Deep-Embedded Clustering (DEC) method that uses a high dimensional traffic data observed at all signalized intersections in a traffic signal control sub area (SA). So far, signal timing plan has been determined based on the traffic data observed at the critical intersection in SA. The current method has a limitation that it cannot consider a comprehensive traffic situation in SA. The proposed method alleviates the curse of dimensionality and turns out to overcome the shortcomings of the current signal timing plan.

• Journal of Korean Society of Transportation
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• v.22 no.7 s.78
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• pp.161-167
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• 2004

While most or fixed-time control systems such as UTCS produce the signal timing plans that either maximizing bandwidth or minimizing a disutility index of delay and stops, cannot consider the fluctuation of traffic flow. One category of the traffic-response control systems, which make small changes on a predefined signal plan such as SCOOT, cannot be easily modified for feedback real-time control schemes based on observation of variables other than traffic flow. The other category, which decide to whether switch the traffic lights or not at each step of time as in PRODYN, does not adequately consider the relations between traffic flows and traffic lights at each step of time. In this paper we present a complete formulation that adequately consider the relations between traffic flows and traffic lights at each step of time. The formulation is a binary mixed integer linear programing (BMILP) that obtain traffic lights at each step for minimizing delay. Since numarical examples for application of the proposed model illustrated that the model adequately produced dynamic traffic signal plans minimizing delay at each step, the model may be expected to contribute to advanced transportation management systems (ATMS) for dynamic traffic signal control.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.3
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• pp.14-27
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• 2020

Pedestrian deaths account for a high percentage of deaths in traffic accidents in Korea, raising interest in pedestrian safety policy. However, since the walk signal time is applied based on the length of the crosswalk without considering the walker and the signal cycle, the walk waiting time is relatively longer than the crosswalk, causing pedestrian jaywalking. In this study, due to an unreasonable signal time plan during a road crossing where a signal is installed, the pedestrian's walk signal was given twice a cycle of crossings, and the operational and safety effects of the signal system were quantitatively and qualitatively analyzed, and the operational effects of the signal interval and jaywalking rate were assessed by different signal intervals. The results showed that jaywalking and waiting time decreased, and the shorter the interval between the application of the walk signal time, the less jaywalking is analyzed. However, there is a risk of vehicle conflict due to pedestrian exposure, and measures for expanding safety for operation were proposed.

• Journal of Korean Society of Transportation
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• v.16 no.2
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• pp.145-155
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• 1998

대도시 가로망의 대부분은 신호교차로와 신호교차로가 연결되는 가로(link)로 구성되어 있어 가로의 통행시간은 가로의 주변여건, 차량간의 상호작용 및 교통신호등과 같은 요소에 영향을 받게된다. 따라서 본 연구의 목적은 대도시 가로망에서 신호 연동체계로 운영되는 가로의 통행시간을 예측할 수 있는 모형을 개발하는데 있다. 본 연구는 대구광역시 가로망을 대상으로 연동가로의 교통흐름을 가장 잘 나타내는 Greenberg모형을 이용하여 연동가로의 통행시간 모형을 도출하였다. 도출된 연동가로의 통행시간 모형은 임계통행시간$(t_m$)과 교통량 대가로최대교통량비$(q/q_m)$의 함수로 이루어졌다. $t_m$모형은 안정류상태의 통행시간 및 불안정류상태의 통행시간의 비를 이용하여 개발하였고 가로 용량모형은 상류부와 하류부의 신호조건에 따른 변수와 가로길이를 변수로 하는 모형을 개발하였다. 개발된 모형은 대구광역시를 대상으로 조사한 12개의 연동가로의 자료를 적용하여 연동으로 운영되는 가로의 통행시간 모형을 도출하였다. 도출된 통행시간 모형은 도로용량에 제시한 모형에 비하여 간단하게 가로의 통행시간을 추정할 수 있으며 교통계획에 적용되는 통행시간모형 비하여 가로의 신호 및 운영조건을 포함한 세부적인 통행시간 모형이다.

• Proceedings of the KOR-KST Conference
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• 1998.10b
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• pp.296-296
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• 1998

고속도로 교통축은 고속도로와 운전자가 대체도로로 이용할 수 있는 표면가로로 구성된 가로망을 말한다. 이러한 고속도로에서의 도로망의 효율을 극대화하기 위해서 시행되고 있는 제어기법으로는 고속도로 진입램프에서의 램프미터링과 표면가로에서의 신호시간조정 등을 들 수 있다. 그러나, 이를 통합한 제어전략은 아직 고려되고 있지 못하다. 고속도로에서 사고나 극심한 혼잡으로 인해 지체가 되었을 경우 단순히 진입램프에서 램프미터링만을 실행하는 것이 아니라 부체도로로의 경로전환을 통해 고속도로교통축의 효율을 극대화할 수 있다. 이는 지능형교통체계(ITS)에서 고려하고 있는 경로안내시스템과도 결부된다. 그러므로, 고속도로 교통축에서는 진입램프에서의 램프미터링전략과 진출램프에서의 경로전환전략, 표면가로에서의 신호최적화전략을 통한 제어를 실행할 수 있다. 따라서, 본 논문에서는 고속도로에서의 진입램프미터링과 진출램프를 통한 경로전환, 표면가로에서의 신호시간조정을 통합한 제어모형을 구축하고, 그에 따른 통합제어알고리즘을 개발하는 것을 본 논문의 목적으로 한다. 통합제어모형은 적정 제어변수의 값을 구하기 용이하게 하기 위해 선형계획법을 적용하였으며, 시뮬레이션을 통해 통합제어알고리즘을 우수성을 검증하였다.

• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.52-61
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• 2018

This research suggested the traffic signal timing calculation model for signal intersections based on sectional travel time. A detection system that collects sectional travel time data such as Urban Transport Information System(UTIS) is applied. This research developed the model to calculate saturation flow rate and demand volume from travel time information using a deterministic delay model. Moreover, this model could determine the traffic signal timings to minimize a delay based on Webster model using traffic demand volume. In micro simulation analysis using VISSIM and its API ComInterface, it checked the saturation conditions and determined the traffic signal timings to minimize the intersection delay. Recently, sectional vehicle detection systems are being installed in various projects, such as Urban Transportation Information System(UTIS) and Advanced Transportation Management System(ATMS) in Korea. This research has important contribution to apply the traffic information system to traffic signal operation sector.

• Journal of Korean Society of Transportation
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• v.30 no.6
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• pp.71-80
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• 2012

This research suggested a real-time traffic signal control algorithm using individual vehicle travel times on an isolated signal intersection. To collect IDs and passing times from individual vehicles, space-based surveillance systems such as DSRC were adopted. This research developed models to estimate arrival flow rates, delays, and the change rate in delay, by using individual vehicle's travel time data. This real-time signal control algorithm could determine optimal traffic signal timings that minimize intersection delay, based on a linear programming. A micro simulation analysis using CORSIM and RUN TIME EXTENSION verified saturated intersection conditions, and determined the optimal traffic signal timings that minimize intersection delay. In addition, the performance of algorithm varying according to market penetration was examined. In spite of limited results from a specific scenario, this algorithm turned out to be effective as long as the probe rate exceeds 40 percent. Recently, space-based traffic surveillance systems are being installed by various projects, such as Hi-pass, Advanced Transportation Management System (ATMS) and Urban Transportation Information System (UTIS) in Korea. This research has an important significance in that the propose algorithm is a new methodology that accepts the space-based traffic surveillance system in real-time signal operations.