• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.3
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• pp.57-66
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• 2007

Weaving is defined as the crossing of two or more traffic streams traveling in the same general direction along a significant length of highway without the aid of traffic control devices. Compared with other freeway sections, perturbation is easy to happen at weaving section. Because there are a lot of lane-changing maneuvers at the weaving section, traffic is subject to turbulence in excess of that normally presents on freeway basic section. This turbulence causes operational problems and its impact must be considered. The purpose of this paper is to perform a basic study on flow characteristics by lane, which can be achieved through analyzing breakdown phenomenon in the microscopic approach. The study made use of data derived from the aerial photography for the microscopic analysis. This research produced the 30-second interval data such as flows, speeds, and densities for the macroscopic analysis and derived the vehicular data to draw time-space diagram for the microscopic analysis. The paper analyzed the traffic characteristics using flows, speeds and densities variation and investigated the conditions of breakdown occurrence with the time-space diagrams. The breakdown phenomenon was identified at weaving section and the propagation from free flow to synchronized flow was observed in this study. In the future, the findings help develop the traffic operational algorithm to manage the traffic congestion under ubiquitous circumstance since the conditions of breakdown Phenomenon can be understood more.

• Journal of Korean Society of Transportation
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• v.17 no.4
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• pp.33-44
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• 1999

LED(Light Emitting Diodes)는 반도체를 이용한 발광소자로서 동화상 광고물이나 가변정보표지판(VMS)등에 주로 활용되고 있으며 최근 외국의 경우 LED 기술을 교통신호등에 적용하여 시범설치 및 확대 적용 설치하여 운영 중에 있으며 국내에서는 산업체, 학계, 연구소 등에서 연구 개발 중에 있다. 본 연구는 현재 이러한 산 학 연의 노력에 의해 개발된 LED 교통신호등을 현장에 적용하기에 앞서서 실내실험과 현장실험을 통하여 에너지 절감효과 및 현장적용성을 검증하고 경제성 분석을 통한 타당성을 제시하는 데 목적이 있다. 연구 내용으로써 기존 전구식 신호등과 LED 신호등의 발광원리 및 특징 비교 분석, 실내실험을 통한 에너지 절감효과 검증, LED 보행자 신호등 현장적용성 평가, LED 신호등으로 서울시의 기존 신호등을 연차적으로 교체하는 경우에 대한 경제적 분석이 실시되었다. 실내실험을 통해 LED 신호등의 에너지 절감효과가 평균 76% 임을 검증하였고 보행자 신호등에 대한 현장 실험에서 설문응답자의 83.7%가 LED 신호등의 시인성이 우월하다고 나타나 현장적용성은 긍정적인 것으로 나타났다. LED 신호등에 대한 경제성 분석결과 자본회수기간은 6년으로 나타났으며 향후 기존 신호등의 고장 및 유지 보수 등에 의한 차량정체 비용, 교통사고 비용 및 소자기술 발전을 고려하면 이보다 단축될 것으로 판단된다. 향후 차량등에 대한 운전자들의 반응 및 장기적인 안정성 등에 대한 종합적인 실험이 추가적으로 이뤄져야 할 것이며 이를 바탕으로 하여 LED 신호등에 대한 규격서 제정 등 법 제도 측면이 이루어진 후 LED 국내 기술 수준 등을 총체적으로 고려하여 LED 교통신호등에 대한 보급방안이 강구되어야 할 것이다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.586-589
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• 2018

As the convergence of traffic system and Big-data technology, new convenient services which is helpful for drivers and pedestrian are appeared. Recently, the various researches about the traffic system, such as prediction of traffic jam and finding the shortest path, are studied. In this paper, we collect the data of taxi trips in Daegu City, and visualize them on the map of Daegu City. And then, we select specific sections of roads in the city, and by using the data of location and speed about taxis and the information of the road sections, calculate the traffic of that section and the average speed of cars on that section. As a result of this, we give help solving the problem of the specific road sections.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.07a
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• pp.427-428
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• 2014

화재발생 시 인명 안전을 위하여 초기의 화재감지가 매우 중요한 요인이다. 기존 연기감지기의 경우 일정한 조건만 맞으면 작동하기 때문에 비화재보의 우려가 높다. 특히 차량 매연도 연료가 연소되어 나오는 연기이므로 차량정체 시 트럭 등에서 발생하는 심한 매연에도 반응하여 오작동의 가능성이 높다. 이러한 기존 화재감지기의 문제점을 해결하기 위해 다양한 IR 레이저 기반 연기검출장치가 활용되고 있다. 하지만 IR 레이저 기반 연기검출장치는 100m 거리가 이격된 레이저 발광부와 수광부 구조에 따라 발광부 레이저광선의 각도변화에 따른 수광부 레이저 포인트 위치가 매우 민감하게 변화함에 따라 초기 레이저 포인트의 초점을 정확히 정합하고, 이후 보정하기 위한 고정밀 자동 초점 정합장치가 필요하다. 이에 본 논문에서는 레이저 투광부와 수광부를 분리하여 레이저 송신기, 수신기로 구성되는 고정밀 자동초점 정합장치를 설계하고자 한다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.1 s.12
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• pp.13-26
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• 2007

A VDS data in the domestic has been used within limits to real time information such as congestion management, incident management, and route guidance service. On the other hand, a VDS data in the foreign countries had been used to various objectives such as transportation policy assessment, transportation construction evaluation, franc safety improvement, and etc. The scope and method of the study is the VDS data which was installed in the uninterrupted flow such as the freeway and the interrupted flow in a diversion route of the leeway. It has investigated and analyzed the VDS as our subject to study, study objective and study methodology for each study generally classified as 1) data collection 2) data processing 3) data store and 4) data quality section. This study has investigated and analyzed the various literatures in domestic and foreign countries regarding the VDS data. And It drew the development direction of the study which is about VDS data in domestic from now.

• The KIPS Transactions:PartD
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• v.14D no.7
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• pp.707-718
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• 2007

Recently, much studies for providing mobile users with suitable and useful content services, LBS(Location Based Service) corresponding to the change of users' location, are actively going on. First and foremost, this is basically owing to the progress of location management technologies such as GPS, mobile communication technology and the spread of personal devices like PDA and the cellular phones. Besides, the research scope of LBS has been changed from vehicle tracking and navigation services to intelligent and personalized services considering the changing information of conditions or environment where the users' are located. For example, it inputs the information such as heavy traffic, pollution, and accidents. The query languages which effectively search the stored vehicle and environment information have been studied depending on the increase of the information utilization. However, most of existing moving object query languages are not enough to provide a recommendation service for a user, because they can not be tested and evaluated in real world and did not consider changed environment information. In order to retrieve not only a vehicle location and environment condition but also use them, we suggest a moving object query language for recommendation service and implement a moving object query process system for supporting a query language. It can process a nearest neighbor query for recommendation service which considers various attributes such as a vehicle's location and direction, environment information. It can be applied to location based service application which utilizes the recommended factors based on environmental conditions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.5D
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• pp.443-451
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• 2010

This paper proposes the methodology about advisory safety speed based on real-time vehicular data collected from highway. The proposed model is useful information to drivers by appling seamless wireless communication and being collected from ECU(Engine Control Unit) equipment in every vehicle. Furthermore, this model also permits the use of realtime sensing data like as adverse weather and road-surface data. Here, the advisory safety speed is defined "the safety speed for drivers considering the time-dependent traffic condition and road-surface state parameter at uniform section", and the advisory safety speed model is developed by considering the parameters: inter-vehicles safe stopping distance, statistical vehicle speed, and real-time road-surface data. This model is evaluated by using the simulation technique for exploring the relationships between advisory safety speed and the dependent parameters like as traffic parameters(smooth condition and traffic jam), incident parameters(no-accident and accident) and road-surface parameters(dry, wet, snow). A simulation's results based on 12 scenarios show significant relationships and trends between 3 parameters and advisory safety speed. This model suggests that the advisory safety speed has more higher than average travel speed and is changeable by changing real-time incident states and road-surface states. The purpose of the research is to prove the new safety related services which are applicable in SMART Highway as traffic and IT convergence technology.

• KIISE Transactions on Computing Practices
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• v.21 no.3
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• pp.223-238
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• 2015

Ramp metering is the most effective and direct method to control a vehicle entering the freeway. This paper proposed the new density-based ramp metering method. Existing methods that use the flow data had low reliability data and can have various problems. Also, when the ramp metering was operated by freeway congestion, the additional congestion and over-capacity can occur in the ramp. To solve this problem with the existing method, the proposed method used the density and acceleration data of the freeway and considered the ramp status. The developed strategy was tested on Trunk Highway 62 west bound (TH-62 WB) in Minnesota Twin-City and compared with Stratified Zone Metering(SZM), which had been operating in the Twin-City freeway. To constitute the experiment environment, the VISSIM simulator was used. The Traffic Information and Condition Analysis System (TICAS) was developed to control the PTV VISSIM simulator. The experiment condition was set between 2:00 PM and 7:00 PM, Oct 5th, 2014 during severe traffic congestion. The simulation results showed that total travel time was reduced by 20% for SZM. Thus, we solved the problem of ramp congestion and over-capacity.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.2
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• pp.1-14
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• 2007

The purpose of this research is to investigate service item to develop archived VDS(Vehicle Detecting System) data user services. Through the review of related studies and literature and investigation of the current application status of the vehicle detector data, the service item from the historical detector data were identified. The relative importance of the identified service item was measured based on the application purpose, usage and frequency of application.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.2
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• pp.1-8
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• 2011

Traffic congestion is a source of significant economic and social costs in urban areas. Intelligent Transportation Systems (ITS) are a promising means to help alleviate congestion by utilizing advanced sensing, computing, and communication technologies. This paper proposes and investigates a basic and advanced ITS framework Advanced Traveler Information System (ATIS) using wireless Vehicle to Roadside (Centralized ATIS model: CA model) and Vehicle to Vehicle (DeCentralized ATIS model: DCA model) communication and assuming an ideal communication environment in the typical $6{\times}6$ urban grid traffic network. Results of this study indicate that an ATIS using wireless communication can save travel time given varying combinations of system characteristics: traffic flow, communication radio range, and penetration ratio. Also, all tested metrics of the CA and DCA models indicate that the system performance of both models is almost identical regardless of varying traffic demand and penetration ratios. Therefore, DCA model can be a reasonable alternative to the fixed infrastructure based ATIS model (CA model).