• Title, Summary, Keyword: Congestion Management

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Subway Congestion Prediction and Recommendation System using Big Data Analysis (빅데이터 분석을 이용한 지하철 혼잡도 예측 및 추천시스템)

  • Kim, Jin-su
    • Journal of Digital Convergence
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    • v.14 no.11
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    • pp.289-295
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    • 2016
  • Subway is a future-oriented means of transportation that can be safely and quickly mass transport many passengers than buses and taxis. Congestion growth due to the increase of the metro users is one of the factors that hinder citizens' rights to comfortably use the subway. Accordingly, congestion prediction in the subway is one of the ways to maximize the use of passenger convenience and comfort. In this paper, we monitor the level of congestion in real time via the existing congestion on the metro using multiple regression analysis and big data processing, as well as their departure station and arrival station information More information about the transfer stations offer a personalized congestion prediction system. The accuracy of the predicted congestion shows about 81% accuracy, which is compared to the real congestion. In this paper, the proposed prediction and recommendation application will be a help to prediction of subway congestion and user convenience.

A Study on the Rescheduling of Generation Considering Contingency in Power System with Wind Farms (풍력발전단지가 연계된 전력계통에서 상정고장을 고려한 발전력 재조정에 관한 연구)

  • Choi, Soo-Hyun;Kim, Kyu-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.2
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    • pp.255-260
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    • 2017
  • This paper studies on effective rescheduling of generation when the single line contingency has occurred in power system with wind farm. The suggested method is formulated to minimize the rescheduling cost of conventional and wind generators to alleviate congestion. The generator rescheduling method has been used with incorporation of wind farms in the power system. Since all sensitivity is different about congestion line, Line Outage Distribution Factor(LODF) and Generator Sensitivity Factor(GSF) is used to alleviate congestion. The formulation have been proccessed using linear programming(LP) optimization techniques to alleviate transmission congestion. The effectiveness of the proposed rescheduling of generation method has been analyzed on revised IEEE 30-bus systems.

Development of AMIS Method (AMIS기법 개발에 관한 연구)

  • 정진혁
    • Proceedings of the KOR-KST Conference
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    • pp.47-52
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    • 1999
  • The methods currently in use to evaluate traffic impacts on the transportation network involve some fundamental shortcomings. First, the methodss do not properly take into account regional and local traffic impacts on the transportation network simultaneously. Second, temporal distribution of traffic, a major contributor to transportation problems, is not accurately accounted for. Third, traffic impact studies require costly and labor-intensive efforts to collect necessary data and to establish to collect necessary data and to establish traffic impact models. In this research, a new method called AMIS is developed for congestion management, access control, and impact simulation to overcome the shortcomings involved in the current methods. The new method is designed for a variety of scenarios such as access management strategies, land use policies, traffic impacts, and other congestion management strategies. This method can effectively be used, with little modification, anywhere in the United States. It is an improvement over the current traffic impact simulation methods that produces more reliable and accurate traffic impact estimates. The case studies conducted in this research have offered evidence that the new method, AMIS, is a credible congestion management tool. Most importantly, a case study presented in this paper illustrates how the new method can be used not only to estimate regional and local impacts of alternate supply management policies in the course of a day, but virtually on an hour-by-hour basis.

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A New Queue Management Algorithm for Improving Fairness between TCP and UDP Flows (TCP와 UDP 플로우 간의 공정성 개선을 위한 새로운 큐 관리 알고리즘)

  • Chae, Hyun-Seok;Choi, Myung-Ryul
    • The KIPS Transactions:PartC
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    • v.11C no.1
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    • pp.89-98
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    • 2004
  • AQM (Active Queue Management) techniques such as RED (Random Early Detection) which be proposed to solve the congestion of internet perform congestion control effectively for TCP data. However, in the situation where TCP and UDP share the bottleneck link, they can not solve the problems of the unfairness and long queueing delay. In this paper, we proposed an simple queue management algorithm, called PSRED (Protocol Sensitive RED), that improves fairness and decreases queueing delay. PSRED algorithm improves fairness and decreases average queue length by distinguishes each type of flow in using protocol field of packets and applies different drop functions to them respectively.

FaST: Fine-grained and Scalable TCP for Cloud Data Center Networks

  • Hwang, Jaehyun;Yoo, Joon
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.8 no.3
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    • pp.762-777
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    • 2014
  • With the increasing usage of cloud applications such as MapReduce and social networking, the amount of data traffic in data center networks continues to grow. Moreover, these appli-cations follow the incast traffic pattern, where a large burst of traffic sent by a number of senders, accumulates simultaneously at the shallow-buffered data center switches. This causes severe packet losses. The currently deployed TCP is custom-tailored for the wide-area Internet. This causes cloud applications to suffer long completion times towing to the packet losses, and hence, results in a poor quality of service. An Explicit Congestion Notification (ECN)-based approach is an attractive solution that conservatively adjusts to the network congestion in advance. This legacy approach, however, lacks scalability in terms of the number of flows. In this paper, we reveal the primary cause of the scalability issue through analysis, and propose a new congestion-control algorithm called FaST. FaST employs a novel, virtual congestion window to conduct fine-grained congestion control that results in improved scalability. Fur-thermore, FaST is easy to deploy since it requires only a few software modifications at the server-side. Through ns-3 simulations, we show that FaST improves the scalability of data center networks compared with the existing approaches.

A Study on The Generation Redispatch for Congestion Management of Transmission Lines (송전선 혼잡 해소를 위한 발전력 재배분 기법 연구)

  • Jung, Jae-Ok;Lee, Kwang-Ho
    • Proceedings of the KIEE Conference
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    • pp.347-349
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    • 2000
  • Under an open transmission access, the generation dispatch is determined by the bidding process of market participants. Congestion occurs when the dispatch would result in the violation of operational constraints. Congestion problem is formulated and solved by OPF(optimal power flow) calculation. The objective functions in OPF are given as quadratic cost functions or piecewise linear functions of bidding functions. In this study, the optimization technique of generation dispatch is presented for the combination of two types of quadratic and linear cost functions.

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A Queue Management Algorithm for Improving Fairness in a Private Network (사설 망의 공정성을 향상시키기 위한 큐 관리 알고리즘)

  • Kang, Tae-Hyung;Koo, Ja-Hon;Chung, Kwang-Sue
    • Journal of KIISE:Information Networking
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    • v.29 no.5
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    • pp.524-532
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    • 2002
  • With the recent rapid progress of Internet, the higher speed network is needed to support the exploration of ambient information from text-based to multimedia-based information. Also, demands for additional Layer 3 routing technique, such as Network Address Translator (NAT) and Firewall, are required to solve a limitation of a current Internet address space and to protect the interior network from the exterior network. However, current router-based algorithms do not provide mechanisms to solve the congestion and fairness problems, while supporting the multimedia services and satisfying the user requirements. In this paper, to solve these problems, a new active queue management, called MFRED (Multiple Fairness RED) algorithm, is proposed. This algorithm can efficiently reduce the congestion in a router or gateway based on the Layer 3 routing technique, such as NAT. This algorithm can improve the fairness among TCP-like flows and unresponsive flows. It also works well in fairly protecting congestion-sensitive flows, i.e. fragile TCP, from congestion-insensitive or congestion-causing flows, i.e. robust TCP.

A TCP-Friendly Congestion Control Scheme using Hybrid Approach for Reduction of Transmission Delay for Real-Time Video Stream (실시간 비디오 스트림의 전송지연 축소를 위한 TCP 친화적 하이브리드 혼잡제어 기법)

  • 김형진;조정현;나인호
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.8 no.2
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    • pp.304-309
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    • 2004
  • Recently, the needs for multimedia stream such as digital audio and video in the Internet has increased tremendously. Unlike TCP, the UDP protocol, which has been used to transmit streaming traffic thorough the Internet, does not apply any congestion control mechanism to regulate the data flow thorough the shared network And it leads to congestion collapse of the Internet and results in long-term transmission delay. To avoid any adverse effect on the current Internet functionality, a now protocol of modification or addition of some functionality to perform congestion control and to reduce huge transmission delay in transmitting of multimedia stream are in study. TCP-friendly congestion control mechanism is classified into two : one is window-based congestion control scheme using general window management functionalities, the other is rate-based congestion control scheme using TCP modeling equation. In this paper, we propose an algorithm for improving the transmitting rate on a hybrid TCP-friendly congestion control scheme combined with widow-based and late-based congestion control for multimedia stream. And we also simulate the performance of improved TEAR implementation using NS. With He simulation results, we show that the improved TEAR can provide better fairness and lower rate fluctuations than TCP.

A development of traffic information detection using camera

  • 김양주;한민홍
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • pp.316-323
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    • 1995
  • This paper presents an image processing technique to get traffic information such as vehicle volume, velocity, and occupancy for measuring the traffic congestion rate. To obtain these information, two horizontal lines are previously set on the screen. A moving vehicle is detected using the gray level difference on each line, and also template matching method at night. Threshold values are determined by sampling pavement grey level, and updated dynamically to cope with the change of ambient light conditions. These technique is successfully used to calculate vehicle volume, occupancy, and velocity. This study can be applied to traffic signal control system for minimizing traffic congestion in urban areas.

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Mathematical Modeling for Traffic Flow (교통흐름의 수학적 모형)

  • Lee, Seong-Cheol
    • Journal of the Korea Safety Management and Science
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    • v.13 no.1
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    • pp.127-131
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    • 2011
  • Even if there are no causing factors such as car crash and road works, traffic congestion come from traffic growth on the road. In this case, estimation of traffic flow helps find the solution of traffic congestion problem. In this paper, we present a optimization model which used on traffic equilibrium problem and studied the problem of inverting shortest path sets for complex traffic system. And we also develop pivotal decomposition algorithm for reliability function of complex traffic system. Several examples are illustrated.