• Title/Summary/Keyword: 대기행렬 제어

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A Study on Functionality Evaluation Method of Real-time Traffic Signal Control System (실시간 신호제어시스템 기능성 평가방법론에 관한 연구)

  • Lee, Choul-Ki;Oh, Young-Tae;Lee, Hwan-Pil;Yang, Ryun-Ho
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.7 no.1
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    • pp.42-58
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    • 2008
  • Nowadays the installation of Real-time Traffic Signal Control system is gradually spread, in order to solve the traffic problem which become serious. The most important thing are reliability of data collection and functionality of system in Real-time Traffic Signal Control System. But, the evaluation for those introduction system are defective after system constructing. So, many systems are not working properly to those systems's primarily purpose. This study is executed expansion through field test and analysis which check performance and advise of system operation. It has purpose to establish of the maintenance system of Real-time Traffic Signal Control system. As the result of analysis, we could find the several problems in this study. So, we also could guess that the effective maintenance systems of the Real-time Traffic Signal Control system is necessary within few years.

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Determination of Control Time Point for Internal Metering Policy Application within COSMOS Environments (실시간신호시스템 환경내 내부미터링 적용 시점에 관한 연구)

  • Lee, Sang-Soo;Song, Sung-Ju;Lee, Choul-Ki
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.7 no.1
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    • pp.22-31
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    • 2008
  • RT/IMPOST is an effective algorithm that can realize real-time internal metering policy (IMP) using queue information from loop detector and signal control strategies. In this paper, an investigation was made to adopt the IMP methodology within COSMOS environments in terms of communication environment and control time point. Through the analysis of the communication environment of COSMOS and communication and control steps in RT/IMPOST, a set of applicable alternative were developed and evaluated. Then, one of the alternatives was selected, and performance of the alternative was compared with RT/IMPOST system using a simulation technique. Results showed that two techniques produced the similar performance. Therefore, the method suggested in this paper was evaluated as a practically viable alternative.

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A Dynamic Simulation and LQR Control for Performance Improvement of Small Gas Turbine Engine (소형 가스터빈엔진의 동적모사와 성능향상을 위한 LQR 제어)

  • 공창덕;기자영;김석균
    • Journal of the Korean Society of Propulsion Engineers
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    • v.1 no.1
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    • pp.24-32
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    • 1997
  • A nonlinear dynamic simulation of a small gas turbine engine was performed by using DYNGEN program with various environmental conditions. It was observed that the effect of the bleed air flow rate changed to overall engine performance. The real time linear model which was a function of engine rotor speed was resulted to be close to nonlinear simulation results. For optimal LQR controller, it was considered only fuel flow rate or both fuel flow rate and bleed air rate as inputs. In the comparison of both results, the LQR controller with multi input had better performance than that with single input.

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A Dynamic Simulation and LQR Control for Performance Improvement of Small Turbojet Engine (소형 터보제트엔진의 동적모사와 성능향상을 위한 LQR 제어)

  • 공창덕;기자영;김석균
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 1997.04a
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    • pp.55-60
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    • 1997
  • A nonlinear dynamic simulation was performed by using DYNGEN program with various environmental conditions. It was observed that the effect of the bleed air flow rate changed to overall engine performance. The real time linear model which was a function of rpm was resulted to be close to nonlinear simulation results. For optimal LQR controller, it was considered only fuel flow rate or both fuel flow rate and bleed air rate as inputs. In the comparison of both results, the LQR controller with multi input had better performance than that with single input.

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A study on the optimization of network resource allocation scheme based on access probabilities (접근확률 기반의 네트워크 자원할당방식의 최적화에 관한 연구)

  • Kim Do-Kyu
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.10 no.8
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    • pp.1393-1400
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    • 2006
  • This paper optimizes the access probabilities (APs) in a network resource allocation scheme based on access probabilities in order that the waiting time and the blocking probability are minimized under the given constraints, and obtains its performance. In order to optimize APs, an infinite number of balance equations is reduced to a finite number of balance equations by applying Neuts matrix geometric method. And the nonlinear programming problem is converted into a linear programming problem. As a numerical example, the performance measures of waiting time and blocking probability for optimal access probabilities and the maximum utilization under the given constraints are obtained. And it is shown that the scheme with optimal APs gives more performance build-up than the strategy without optimization.

A Study on Signal Control Algorithms using Internal Metering for an Oversaturated Network (내부 미터링을 이용한 과포화 네트워크 신호제어 알고리즘 연구)

  • Song, Myeong-Gyun;Lee, Yeong-In
    • Journal of Korean Society of Transportation
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    • v.25 no.6
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    • pp.185-196
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    • 2007
  • The aim of this research is to develop a signal control algorithm using internal metering to minimize total delay that vehicles go through, in case a network is oversaturated. To calculate total delay on the network, the authors first detect vehicles' arrivals and departures in the network through the detecting system, and chase the vehicles' flow in the links with a platoon dispersion model. Following these, the authors calculate the queue length in all the inks of the network through the chase of vehicles, deduce the stopped time delay, and finally convert the stopped time delay to the approach delay with a time-space diagram. Based on this calculated delay, an algorithm that calculates the level of the internal metering necessary to minimize the deduced approach delay is suggested. To verify effectiveness of this suggested algorithm, the authors also conduct simulation with the micro-simulator VISSIM. The result of the simulation shows that the average delay per vehicle is 82.3 sec/veh and this delay is lower than COSMOS (89.9sec/veh) and TOD (99.1sec/veh). It is concluded that this new signal control algorithm suggested in this paper is more effective in controlling an oversaturated network.

Field Application Analysis of Center Control Emergency Vehicle Preemption System (중앙제어방식 긴급자동차 우선신호 현장적용성 분석)

  • Lee, Young-Hyun;Han, Seung-Chun;Jeong, Do-Young;Kang, Jin-Dong
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.18 no.6
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    • pp.137-154
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    • 2019
  • This study analysed the center control emergency vehicle preemption[EVP] test result on the 1.782 km section around Gangbuk Fire Station. The pros and cons between center control and site control EVP was compared through the review of existing research. The test site was selected based on the higher link speed for choosing low congested area and 4 to 6 lane road. EVP operates green extension under the estimated arrival time to each intersection. This study is about EVP system field application and its evaluation by analyzing EVP operation result with the emergency vehicle's trace, GPS data. The impact on the surrounding traffic was analysed in delay from the queue length survey. Analysis showed the decrease in averge travel time 41.81%, but the increase in delay of surrounding traffic slightly. It is expected that EVP can be applied to the expanded area by researching EVP compensation scheme.

A Queueing Model with Loss and Time Priority for Optimal Buffer Control in ATM (손실 우선과 시간 우선이 공존하는 ATM에서의 최적 버퍼 제어를 위한 대기 행렬 모형)

  • Lee, H.W.;Kim, E.Y.
    • Journal of Korean Institute of Industrial Engineers
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    • v.25 no.1
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    • pp.130-140
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    • 1999
  • This paper deals with a priority queueing model in an ATM system. Two types of customers are considered. Type-1 customers have push-put priority over type-2 customers. Type-1 customers can enter the service only when the number of type-2 customers is less than a threshold T. We derive the joint probability of the number of customers in the buffer, the mean waiting time, and the loss probabilities of each type. We also propose an optimal control policy that satisfies a given quality of service.

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VQS4 Mechanism for the Priority Control in ATM Traffic (ATM 트래픽 성능향상을 위한 대기행렬구조의 제안 및 평가)

  • 안정희
    • Proceedings of the Korea Society for Simulation Conference
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    • 1998.10a
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    • pp.147-150
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    • 1998
  • ATM 환경의 다양한 QOS를 갖는 트래픽의 우선순위제어를 위해, ATM 스위치의 출력 버퍼에 저장되는 셀의 큐메카니즘을 제안하였다. 제안한 큐 방식은 가변큐공유(VQS4 : Variable Queue Sharing with 4 queue)방식으로서 기존의 고정 큐 방식의 문제점인 버스트 트래픽으로 인한 큐 오버플로우의 문제점을 개선하기 위해 CBR 큐, VBR-rt큐, VBR_nrt 큐, ABR 큐의 영역을 가변적으로 공유하여 큐 자원의 이용율을 최대화시킴으로써 순간 버스트 트래픽 유입으로 인한 셀손실율을 최소화시킬 수 있는 특성을 제공한다. VQS4 방식의 성능을 평가하기 위해 버스트 특성이 강한 트래픽 패턴을 이용하여 고정 큐를 이용한 HOL과 제안 방식인 VQS4의 셀손실률 및 평균 지연률을 비교하였으며 시뮬레이터는 Visual Slam 2.0(AweSim)을 이용하여 작성했다.

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Application and Evaluation of a Traffic Signal Control Algorithm based on Travel Time Information for Coordinated Arterials (연동교차로를 위한 통행시간기반 신호제어 알고리즘의 현장 적용 및 평가)

  • Jeong, Yeong-Je;Kim, Yeong-Chan
    • Journal of Korean Society of Transportation
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    • v.27 no.5
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    • pp.179-187
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    • 2009
  • This study develops a real-time signal control algorithm based on sectional travel times and includes a field test and evaluation. The objective function of the signal control algorithm is the equalization of delay of traffic movements, and the main process is calculating dissolved time of the queue and delay using the sectional travel time and detection time of individual vehicles. Then this algorithm calculates the delay variation and a targeted red time and calculates the length of the cycle and phase. A progression factor from the US HCM was applied as a method to consider the effect of coordinating the delay calculation, and this algorithm uses the average delay and detection time of probe vehicles, which were collected during the accumulated cycle for a stabile signal control. As a result of the field test and evaluation through the application of the traffic signal control algorithm on four consecutive intersections at 400m intervals, reduction of delay and an equalization effect of delay against TOD control were confirmed using the standard deviation of delay by traffic movements. This study was conducted to develop a real-time traffic signal control algorithm based on sectional travel time, using general-purpose traffic information detectors. With the current practice of disseminating ubiquitous technology, the aim of this study was a fundamental change of the traffic signal control method.