• Title/Summary/Keyword: 혼잡도

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An Analytical Procedure to Estimate Non-recurrent Congestion caused by Freeway Accidents (고속도로 교통사고로 인한 비 반복 혼잡 추정 연구)

  • Jeong, Yeon-Sik;Jo, Han-Seon;Kim, Ju-Yeong
    • Journal of Korean Society of Transportation
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    • v.28 no.2
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    • pp.45-52
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    • 2010
  • The objective of this paper is to develop and apply a method that estimates the amount of traffic congestion (vehicle hours of delay) caused by traffic accidents that occur on freeways in Korea. A key feature of this research is the development of a method to separate the non- recurrent delay from any recurrent delay that is present on the road at the time and place of a reported accident. The main idea to separate these two delays is to use the speed difference between speed under accident condition and speed under normal flow condition. For the case study application, two datasets were combined to accomplish the objective of the study: (1) accident data and (2) traffic flow data. Eventually, the results can be useful for the performance evaluation of accident reduction program, for strategic plans to cope with congestion caused by traffic accidents, and for rectification of the estimation method for traffic congestion costs.

Load Factor Decrease In The Seoul Metro Circle Line through Analyzing Passenger OD Demand (2호선 혼잡구간 OD수요 분리유도를 통한 혼잡도 개선 방안 (교통카드 빅데이터 분석을 중심으로))

  • Eom, Jin Ki;Song, Ji-Young;Lee, Kwang-Sub
    • Journal of the Korean Society for Railway
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    • v.17 no.6
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    • pp.457-465
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    • 2014
  • This study proposes a policy for urban railway travel demand management system in order to decrease the load factor of the Seoul metro Circle line, particularly for the segment between Sadang and Samsung stations, through analyzing the transit smart card data. We propose mixed train operations of the existing Circle line and a line that goes toward Samsung station in order to transport passengers that have two distinct groups: those with the destination of Samsung station and those with destinations after Samsung station. The introduction of a mixed train operation that encourages passengers passing through Samsung station to take a Circle line train will decrease the congested load factor by 11.3% during the morning peak hours using the mixed train operation of the Circle and Samsung lines. This policy could be an effective method to decrease the load factor and improve the comfort of rail passengers without extra investment in the railway facilities.

DCCP based Congestion Control Scheme to support Mobility of Devices on Ubiquitous Computing Environment (유비쿼터스 컴퓨팅 환경에서 단말의 이동성을 지원하기 위한 DCCP 기반의 혼잡 제어 정책)

  • Park Si-Yong;Kim Sung-Min;Lee Tae-Hoon;Chung Ki-Dong
    • Journal of KIISE:Information Networking
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    • v.33 no.1
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    • pp.59-75
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    • 2006
  • In this paper, we propose a congestion control scheme to control the congestion due to the mobility of ubiquitous devices on ubiquitous computing environment. Especially, this congestion control scheme provides a reverse congestion avoidance state which can classify between packet error by features of wireless network and packet dropping by congestion. Also, it provides a slow stop state which can minimize bandwidth waste due to congestion control. The proposed congestion control scheme controls more adaptive than existing congestion control schemes. The proposed congestion control scheme is designed based on DCCP(Datagram Congestion Control Protocol) being proposed by IETF(Internet Engineering Task Force) and implemented on the Linux kernel. In simulation results, the proposed congestion control scheme provides good bandwidth throughput in wireless network as well as in wired network.

Improving the Estimation Method of Traffic Congestion Costs (교통혼잡비용 추정방법의 개선방안 연구)

  • Jo, Jin-Hwan;Hwang, Gi-Yeon
    • Journal of Korean Society of Transportation
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    • v.28 no.1
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    • pp.63-74
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    • 2010
  • Recently, there has been increasing demand from academic society in Korea for the improvement of current traffic congestion cost estimation methods. The purpose of this study is to suggest a better way to estimate congestion cost followed by in-depth review regarding traffic congestion. The key improvements proposed in this study include: 1) adding social externality to congestion cost, 2) integrating the green house and environmental pollution impacts with congestion costs, 3) taking non-recurrent traffic congestion costs into account for the assessment, 4) revising the criteria to determining the level of traffic congestion speed, and 5) deciding how to limit congestion measurement period. It is found meaningful that the improvements, notwithstanding difficulties in their real case application, provide invaluable insights in our efforts to change the meaning of congestion cost in an era of sustainable growth.

Comparison of Area Pricing and Cordon Pricing in General Equilibrium Models (구역혼잡통행료와 진입통행료의 비교)

  • Yu, Sang-Gyun;Jeong, Chang-Mu;Lee, Hyeok-Ju
    • Journal of Korean Society of Transportation
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    • v.27 no.2
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    • pp.145-155
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    • 2009
  • This paper compares the relative performances of area and cordon tolls as opposed to the first-best congestion tolls with respect to alleviation of traffic congestion and social welfare. The comparison is done in the monocentric city where all the jobs are located at the city center. The study shows that the size of charging zones is similar in the two second-bests, but that the optimal toll level is higher in area pricing than in cordon pricing. Area pricing schemes turn out to perform better than cordon pricing schemes as measured by average speeds and daily average travel time. Accordingly, the former is shown to increase the social welfare more than the latter. In the case of the cordon tolls, the residents at the charging zones are exempted from the tolls. In this way, cordon tolls invite people into the most congested areas over the optimal level while partially negating the whole spirit of the congestion tolls.

Algorithm for Measuring Traffic Congestion using DCT (DCT를 이용한 교통 혼잡도 측정 알고리즘)

  • Cheong, Seong-Il;Ahn, Cheol-Woong;Choi, Byung-Geol;Kim, Sung-Ho
    • Journal of KIISE:Computing Practices and Letters
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    • v.6 no.2
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    • pp.196-205
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    • 2000
  • As the number of cars is suddenly increasing, the number of cars on road exceeds the capacity of the road. In order to disperse the stream of traffic, there are many approaches for calculating the degree of congestion using traffic monitoring camera, and analyzing the velocity or the number of moving objects. Since those methods use background image, it is necessary to prepare the proper background image. In this paper, we proposed the algorithm to calculate the degree of congestion without background image. We perform DCT to the road image to obtain the edge information of cars, and then use it for calculating the degree of congestion.

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Assessment of Degree of Congestion based on Marine Traffic Flow Simulation for Harbor Area (항만 내 교통류 시뮬레이션에 기초한 혼잡도 평가)

  • Lee Han-Jin;Gong In-Young
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.1 no.1
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    • pp.47-55
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    • 1998
  • In this paper, authors try to assess the marine traffic environment from the viewpoint of the degree of congestion. First, the marine traffic flow simulation is carried out to get the information related to the assessment. The simulation is performed based on the wide investigation of marine traffic environment and some statistical methods. Then the degree of congestion is reasoned by using the reasoning methods of the degree of collision risk made to develop collision avoidance system. The quantified degree of congestion reasoned by this method provides much information needed to the design and the evaluation of marine traffic environment.

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A Router Mechanism for Congestion Control in Internet (인터넷에서 혼잡 제어를 위한 라우터 메커니즘)

  • 박재성;신용철;박희윤;이재용
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.26 no.10A
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    • pp.1746-1755
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    • 2001
  • 본 논문에서는 인터넷 트래픽의 자기 유사성 특성을 이용한 큐 관리 기법을 제안한다. 제안 기법은 LRD 프로세스의 특성을 이용하여 큰 타임 스케일에서 다음 혼잡 검출 주기 동안 평균 트래픽 입력율을 예측하고 이를 통해 혼잡 발생 여부를 미리 검출한다. 혼잡 검출시 입력 패킷을 확률적으로 폐기함으로써 망 내부에서 혼잡 발생을 사전에 방지한다. 제안 기법은 종단 시스템의 혼잡 제어 기법이나 각 플로우의 통신 환경에 무관하게 라우터의 평균 큐 길이와 큐 길이 변이를 작게 유지할 수 있으므로 지연과 지연 변이에 민감한 멀티미디어 서비스 제어에 적합하다. 또한 제안 기법은 입력율 예측을 통해 혼잡을 사전에 검출하기 때문에 종단간 혼잡 제어 기법을 사용하지 않는 플로우들에 의해 발생된 패킷들이 망 자원을 불평등하게 많이 사용하는 현상을 방지한다. 제안 기법은 각 플로우별 상태 정보를 관리하지 않으므로 확장성이 뛰어나며 이로 인해 소수의 PHB에 따라 각 홉별로 차등화된 서비스를 제공하는 Diffserv 구조에 적합하다. 또한 제안 기법은 기존 인터넷 구조에 변화를 주지 않고 라우터의 소프트웨어 업그레이드만으로 서비스가 가능하며, 필요한 버퍼의 양도 크지 않다는 장점을 가진다.

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Improving the performance of TCP over networks of mobile with delaying congestion control in Snoop (Snoop 프로토콜에서 혼잡 제어 지연을 통한 이동망상에서의 TCP 성능향상 기법)

  • Kim, Yong;Sung, Ho-Cheol;Hyeon,Ho-Jae;Han, Sun-Young
    • The KIPS Transactions:PartC
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    • v.8C no.3
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    • pp.351-358
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    • 2001
  • 무선망에서는 유선망에 비해 그 특성상 비교적 많은 패킷을 손실된다. TCP 프로토콜은 흐름제어나 에러정정, 혼잡 제어 등의 기능을 통해 보다 효율적이고 안정적인 통신을 지원하고 있다. 하지만 표준 TCP 프로토콜은 유선망의 특성을 고려하여 개발하였기 때문에 무선망에서 혼잡한 상황에서 패킷이 도달하지 못한 경우와 실제로 패킷이 손실되어 전달되지 못하는 경우를 구분하지 못한다. 최근까지 제시된 여러 이동망 TCP에 대한 논문은 무선망에서 패킷이 손실된 경우 혼잡 제어를 일어나지 못하게 하는 방법을 제시하고 있다. 본 논문에서는 TCP Persist Timer를 이용하여 혼잡제어를 회피하는 방법을 기존에 제시된 Snoop 프로토콜에 적용하여 자체적인 이동망상에서의 TCP 성능향상에 더하여 연속적인 에러에 대한 성능 향상을 제고하고 있다. 개선된 Snoop 프로토콜은 WZACK(Window Size Zero ACKnowledge Packet)을 이용하여 혼잡제어를 정지시킴으로써 비효율적인 혼잡제어를 막도록한다.

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