• Journal of Intelligence and Information Systems
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• v.13 no.3
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• pp.101-117
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• 2007

In this paper, we propose a customized genetic algorithm (GA) to find the minimum-cost guideway network (GN) of personal rapid transit (PRT) subject to connectivity, reliability, and traffic capacity constraints. PRT is a novel transportation concept, where a number of automated taxi-sized vehicles run on an elevated GN. One of the most important problems regarding PRT is how to design its GN topology for given station locations and the associated inter-station traffic demands. We model the GN as a directed graph, where its cost, connectivity, reliability, and node traffics are formulated. Based on this formulation, we develop the GA with special genetic operators well suited for the GN design problem. Such operators include steady state selection, repair algorithm, and directed mutation. We perform numerical experiments to determine the adequate GA parameters and compare its performance to other optimization algorithms previously reported. The experimental results verify the effectiveness and efficiency of the proposed approach for the GN design problem having up to 210 links.

• Journal of KIISE
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• v.41 no.10
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• pp.745-761
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• 2014

To address the problems of existing traffic information acquisition systems such as high cost and low scalability, wireless sensor networks (WSN)-based traffic information acquisition systems have been studied. WSN-based systems have many benefits including high scalability and low maintenance cost. Recently, various sensors are studied for traffic surveillance based on WSN, such as magnetic, acoustic, and accelerometer sensors. However, ultrasonic sensor based systems have not been studied. There are many issues for WSN-based systems, such as battery driven operation and low computing power. Thus, power saving methods and specific algorithms with low complexity are necessary. In this paper, we introduce optimal methodologies for power saving of ultrasonic sensors based on the modeling and analysis in detail. Moreover, a new vehicle detection algorithm for low complexity using ultrasonic data is presented. The proposed methodologies are implemented in a tiny microprocessor. The evaluation results show that our algorithm has high detection accuracy.

• Journal of Korean Society of Transportation
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• v.25 no.4
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• pp.99-108
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• 2007

This paper presents an elastic demand stochastic user equilibrium traffic assignment that could not be easily tackled. The elastic demand coupled with a travel performance function is known to converge to a supply-demand equilibrium, where a stochastic user equilibrium (SUE) is obtained. SUE is the state in which all equivalent path costs are equal, and thus no user can reduce his perceived travel cost. The elastic demand SUE traffic assignment can be formulated based on a dynamic system, which is a means of describing how one state develops into another state over the course of time. Traditionally it has been used for control engineering, but it is also useful for transportation problems in that it can describe time-variant traffic movements. Through the Lyapunov Function Theorem, the author proves that the model has a stable solution and confirms it with a numerical example.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.4
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• pp.44-54
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• 2011

Intelligent transport services on smart roads tend to have a problem at the stage of benefit-cost analysis that can not secure economic feasibility of the new services which increase early investment cost on building its infrastructure. It is expected that the number of road accidents, 'Incident/Accident', will decline through various safety services using intelligent safety facilities, intelligent transport management and so on, and that traffic congestion will also decrease. The effect of traffic congestion reduction could be the benefit by safety improvement, however current investment-analysis process in Korea does not appropriate it as a benefit. This study estimated road blocking time with 'Incident/Accident' classification and highway accident data of past three years. It also developed a generalized model by a regression analysis with a microscopical simulation. Furthermore, it suggested necessary units on quantitative analysis in order to make the developed model applicable to investment evaluation. As a result of applying the developed model to Smart-Highway Project, it showed that total safety improvement benefit is about 139 billion dollars over 30 years when it is supposed that accident decreasing rate by smart safety facilities is 10%.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.5 no.1 s.9
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• pp.31-43
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• 2006

As of March 2005, the standard of traffic signal controllers became effective. The standard presents specifications and functions of a traffic signal controller which collects traffic information, sends it to the traffic control center, and controls traffic signal with adequate traffic signal timing provided by the traffic control center. Since the controllers by the previous standard lack parts compatibility and have different control functions and communication protocol, the maintenance cost has been increased. Also, some important functions like conflict detection have not worked out perfectly. To overcome these disadvantages, first of all, this standard secures hardware compatibility. Conflict detection method has been enhanced. Communication protocol to the traffic control center was included in the standard. With this standard, independent maintenance system and prompt treatment of hardware malfunctions becomes possible. Also, the unified intersection traffic control method will increase traffic safety.

• Journal of Korean Society of Transportation
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• v.25 no.6
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• pp.89-97
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• 2007

The car-dependent traffic system based on highly advanced industrialization and economic growth causes various urban problems including traffic jams, energy consumption, air pollution, noise, car accidents and other issues. Particularly in urban areas, air pollution from motor vehicles is worse than pollution from past industrialization. In this study, therefore, the authors grasped car exhaust reduction effects by using microsimulation and those traffic policies that could make cars flow smoothly, reducing the air pollution in urban areas through analysis on profitability. As a result, the weekday-based car using system has been found most effective as it does not need investment cost. However, this system may be socially unacceptable, as it requires the government to change driver behavior. Therefore, the government needs to first reach a consensus with the citizens regarding this system. This system will also be effective with other alternatives. As a follow-up study, the authors will research citizens' perceived impacts of car exhaust on air pollution through a study on preference and grasp the possibility of applying these study results to real traffic policies.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.253-257
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• 2008

지능형교통시스템 (Intelligent Transportation System: ITS) 은 도로 및 교통관리, 교통정보제공, 대중교통 및 화물차량의 운영 등 교통의 전 분야에 걸쳐 정보통신 기술, 센서 및 제어 기술을 접목함으로써 교통의 효율화와 물류비용의 절감을 목표로 하고 있다. 특히, 최근에는 전자 및 통신 기술 등 첨단기술을 활용하여 현행 교통체계를 첨단화하기 위한 노력이 빠르게 진행되고 있으며, ITS는 최근 위치정보의 폭넓은 보급과 유 무선통신기술의 발전에 따라 위치정보서비스, 텔레매틱스 서비스 등과의 결합을 통해 새로운 비즈니스 모델들을 탄생시키고 있다. 또한 기존에 중점적으로 추진되어 왔던 도로 및 차량 영역뿐만 아니라 ITS 아키텍처를 구성하는 다양한 하위 시스템들간의 통신 및 정보체계 표준화와 관계된 기술, 시스템, 서비스 등의 시장이 형성되기 시작하고 있다. 이중에서도 최근에는 이동통신기술의 발전과 복합단말의 발전을 통해 통합된 기능을 갖는 이동전화, PDA, 스마트단말 등의 개인단말 뿐만 아니라 도로와 차량내의 통신을 위한 차량탑재형 단말 등의 보급으로 단거리 무선통신기술과 스마트차드 기술을 이용한 자동요금징수시스템, 위치정보기술을 이용한 위치기반서비스, GPS를 이용하여 실시간 교통정보 서비스가 가능한 텔레매틱스 서비스 등은 본격적으로 시장을 형성해 나가고 있다. 이는 기존의 ITS 분야가 ETCS(Electric Toll Collection System), AVHS(Advanced Vehicle & Highway System), CVO(Commercial Vehicle Operation)등 교통 인프라에 초점을 맞추고 있었으나 그동안의 수익모델 부재 등으로 인해 사업자들의 적극적인 투자가 이루어지지 않아 ITS 시장 활성화에 어려움이 있어 왔다는 점을 고려해 볼 때 최근 위치정보를 이용한 사용자 서비스를 통해 민간 기업의 투자 참여와 일반 사용자들의 ITS 에 대한 관심이 매우 높아지고 있다는 점은 ITS 시장의 확대에 있어 매우 긍정적인 요인될 것으로 예상되고 있다. 본 논문에서는 이러한 ITS의 세계적인 개발 및 투자 추세, 국내의 추진 동향을 통해 살펴보고 이에 따른 국내 적용에 대한 시사점을 살펴보았다.

• Journal of Korean Society of Transportation
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• v.19 no.5
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• pp.61-70
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• 2001

The origin and destination(O-D) matrix is one of the most important elements in transportation planning process. Traditionally, transport planners survey the O-D movements in order to estimate the O-D matrix. Even though the cost of the O-D survey requires high amounts of resources, the accuracy is relatively low. Therefore, many researchers have studied the estimation of the O-D matrix for automobile from traffic counts. however, there is a little attention for the application on the transit O-D matrix estimation from traffic counts. The objective of this study is therefore the estimation of the transit O-D matrix from traffic counts using Gradient method. which is verified by the reliability analysis using a contrived small example network.

• Journal of Korean Society for Geospatial Information Science
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• v.4 no.1 s.6
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• pp.75-82
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• 1996

As can be seen in US case with the introduction of ISTEA and CAAA, the expansion of the transportation decision-making role of local government is expected to be quite apparent in Korea, and the increased importance of decision-making in transportation issues requires increased attention to both justification and analysis of transportation initiatives. A GIS-based facility management system in a desktop computing environment has been constructed using MapInfo, ARC/INFO, and Microstation to allow such expanded role of local government's decision-making activities. In this paper, first, authors try to explain the procedures of system design; that is, the digital map production including vectorizing, data conversion, attribute data entry, and application programming development. Then, various management functions which are basically embedded in MapInfo environment, and application functions established by the use of MapBasic language has been explored Finally, the possible benefits of combining geographic information systems with traffic planning scheme has also been described with some discussion.

• Journal of Korean Society of Transportation
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• v.22 no.6
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• pp.57-66
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• 2004

When we estimate an origin-destination matrix from traffic counts. origin-destination matrix estimation from traffic counts according to the selected optimal traffic counting links is method for improving the results of origin-destinaation matrix estimation and for increasing economic efficiency. This paper proposed model of selecting traffic counting links using integer program technique, and selected a traffic counting links using this model, and estimated and origin-destingtion matrix from traffic counts according to the selected optimal traffic counting links. Also, we compared a result of estimating origin-destination matrix from the selected optimal traffic counting links using this model to a result of estimating origin-destination matrix from the randomly selected traffic counting links. The error analysis result was more improved a result of origin-destination matrix estimation using this model than a result of randomly selected links.