• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.1
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• pp.1-14
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• 2014

The expansion of the physical road in response to changes in social conditions and policy of the country has reached the limit. In order to alleviate congestion on the existing road to reconsider the effectiveness of this method should be asking. Currently, how to collect traffic information for management of the intersection is limited to point detection systems. Intelligent Transport Systems (ITS) was the traffic information collection system of point detection method such as through video and loop detector in the past. However, intelligent transportation systems of the next generation(C-ITS) has evolved rapidly in real time interval detection system of collecting various systems between the pedestrian, road, and car. Therefore, this study is designed to evaluate the development of an algorithm for queue length based real-time traffic signal control methodology. Four coordinates estimate on time-space diagram using the travel time each individual vehicle collected via the interval detector. Using the coordinate value estimated during the cycle for estimating the velocity of the shock wave the queue is created. Using the queue length is estimated, and determine the signal timing the total queue length is minimized at intersection. Therefore, in this study, it was confirmed that the calculation of the signal timing of the intersection queue is minimized.

• Journal of Korean Society of Transportation
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• v.15 no.2
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• pp.67-82
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• 1997

일반적으로 교통수요가 용량보다 적으면 모든 교통량이 지체없이 신호교차로를 통 과 할 수 있을 것이다. 이러한 비포화 상태에서는 어떻게 Delay나 Stop을 최소화시키느냐가 신호처리의 목적함수가 될 것이다. 그러나 교통수요가 용량보다 많아지면 신호교차로가 모 든 교통량을 통과시키지 못하므로 시간이 갈수록 대기 행렬이 점점 길어질 것이다. 이러한 과포화상태에서는 늘어나는 대기 행렬을 조절하지 못하면 결국에는 Spillback이 상류 교차 로로 확대되어 최악에는 교차로에서의 모든 방향의 움직임을 정지시키는 Gridlock상태로까 지 악화 될 수 있다. 따라서 과포화 상태에서는 비포화 상태와는 달리 늘어나는 대기행렬을 조절하여 통과 교통량을 최대화 시키는 것이 신호처리의 목적 함수가 될 수 있을 것이다. 본 논문에서는 과포화시의 간선도로를 신호처리에 의해 일정한 대기행렬을 유지하므로써 시 스템을 최적화 하는 알고리즘을 개발하였다. IMPOST(Internal Metering Policy to Optimize Signal Timing)는 논문에서 개발한 알고리즘을 C언어로 프로그래밍한 model이다.

• Journal of Korean Society of Transportation
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• v.15 no.3
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• pp.111-130
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• 1997

교통수요가 용량보다 많아지면 신호교차로가 모든 교통량을 통과시키지 못하므로 시간이 갈수록 대기 행렬이 점점 길어질 것이다. 이러한 과포화상태에서는 늘어나는 대기행렬을 조절하지 못하면 결국에는 Spillback이 상류 교차로로 확대되어 최악에는 교차로에서의 모든 방향의 움직임을 정지시키는 Gridlock상태로까지 악화될 수 있다. 따라서 과포화 상태에서는 비포화 상태와는 달리 늘어나는 대기 행렬을 조절하여 통과 교통량을 최대화 시키는 것이 신호처리의 목적 함수가 될 수 있을 것이다. 6월호의 논문에서는 Static 한 상태의 과포화 간선도로를 신호처리에 의해 일정한 대기행렬을 유지하므로써 시스템을 최적화하는 알고리즘을 개발하였다. 그러나 과포화 간선도로의 교통수요는 매 Cycle 마다 Dynamic 하게 변하고, 과포화의 교통상황에서는 미미한 교통 변화가 우리가 염려하는 Spillback 을 야기시킬 수 있기 때문에 본 논문에서는 6월호에서 개발한 알고리즘에 기초하여 실시간으로 신호처리 하는 알고리즘을 개발하였다. 과포화 상태의 5개의 신호교차로를 가진 간선도로를 Simulation 하여 비교한 결과 본 논문에서 개발한 알고리즘이 PASSER II 나 TRANSYT 7F 보다 차량 한 대당 평균 운행시간이 각각 30%, 20% 줄어들었다.

• Journal of the Korea Society for Simulation
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• v.27 no.3
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• pp.45-52
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• 2018

We consider the busy period of an M/G/1/K queueing system with queue-length-dependent overload control policy. A variant of an oscillating control strategy that was recently analyzed by Choi and Kim (2016) is considered: two threshold values, $L_1({\leq_-}L_2)$ and $L_2({\leq_-}K)$, are assumed, and service rate and arrival rate are adjusted depending on the queue length to alleviate congestion. We investigate the busy period of an M/G/1/K queue with two overload control policies, and present the formulae to obtain the expected length of a busy period for each control policy. Based on the numerical examples, we conclude that the variability and expected value of the service time distribution have the most influence on the length of a busy period.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.3
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• pp.45-51
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• 2016

Existing real-time signal control system was brought up typical problems which are supersaturated condition, point detection system and loop detection system. For that reason, the next generation signal control system of advanced form is required. Following thesis aimed at calculating queue length for the next generation signal control system to utilize basic parameter of signal control in crossing queue instead of the volume of real-time through traffic. Overflow saturated condition which was appeared as limit of existing system was focused to set-up range. Real-time location information of individual vehicle which is collected by GPS data. It converted into the coordinate to apply shock wave model with an linear equation that is extracted by regression model applied by a least square. Through the calculated queue length and link length by contrast, If queue length exceed the link, queue of downstream intersection is included as queue length that upstream queue vehicle is judeged as affecting downstream intersection. In result of operating correlation analysis among link travel time to judge confidence of extracted queue length, Both of links were shown over 0.9 values. It is appeared that both of links are highly correlated. Following research is significant using real-time data to calculate queue length and contributing to signal control system.

• Korean Journal of Construction Engineering and Management
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• v.23 no.6
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• pp.3-14
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• 2022

Quantitative analysis of the number of construction workers and construction period can present a new standard for appropriate personnel. This study presents a Queueing model that predicts the execution time of work procedures, the most important factor among work efficiency indicators. During the working cycle of apartment frame construction the same process tends to be repeated the volume of contruction. Based on these characteristics, this study used a Queueing Model and analyzed reference layer cycle of the delayed frame construction. After adjusting the number of people and the construction period, the performance of the model was analyzed and suggested. This study aims to support the decision making of personnel distribution according to the volume of construction by performing a performance analysis of the Queueing Model.

• Journal of the Korea Society for Simulation
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• v.20 no.2
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• pp.1-10
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• 2011

In queueing network analysis, arrival processes are usually modeled as renewal processes by matching mean and variance. The renewal approximation simplifies the analysis and provides reasonably good estimate for the performance measures of the queueing systems under moderate conditions. However, high variability in arrival process or in service process requires more sophisticated approximation procedures for the variability parameter of departure/arrival processes. In this paper, we propose an heuristic approach to refine Whitt's variability function with the k-interval squared coefficient of variation also known as the index of dispersion for intervals(IDI). Regression analysis is used to establish an empirical relationships between the IDI of arrival process and the IDI of departure process of a queueing system.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.874-880
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• 2005

본 논문에서는 D-정책과 복수휴가를 갖는 MAP/G/1 대기행렬시스템의 고객수를 분석한다. 고객도착은 마코비안 도착과정(MAP)을 따른다. 서어버는 바쁜기간 종료 직후 휴가를 떠나고 휴가에서 돌아온 직후의 시스템 총일량이 D를 초과할 때까지 휴가를 반복한다. 만일, 휴가에서 돌아온 직후의 시스템 총일량이 D를 초과하면, 서어버는 즉시 서비스를 시작한다. 본 논문에서는 임의의 이탈시점 고객수분포를 유도하고, 이를 이용하여 임의시점 고객수분포와 평균고객수를 유도한다. 또한, 동일한 조건하에 D-정책과 복수휴가를 갖는 M/G/1 대기행렬시스템의 평균고객수와의 차이를 비교해 본다.

• Korean Journal of Construction Engineering and Management
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• v.24 no.1
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• pp.21-30
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• 2023

Excessive complaints and traffic jams occurred as customers who visited the Drive-thru waited in a long line. Company S recommends DT Pass to reduce the queues. Therefore, this study confirmed the improvement in performance of the queue increasing the number of stores operated by two servers insteaol of one using a queue model. And then confirmed performance improvement by dividing them into DT and DT Pass. After that, the L value derived through the queue model and the number of queues in each store were compared to calculate the number of queues to be additionally provided. Through this, the validity of selecting the minimum number of queues in the future is verified based on the results derived in this study.

• Communications for Statistical Applications and Methods
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• v.16 no.2
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• pp.217-228
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• 2009

In this paper, we consider a multi-class queueing system in which different classes of customers have different arrival rates, service rates and class-transition probabilities. We use the fast simulation method to estimate the overflow probability and the expected number of customers of each class at the first time the total number of customers hits a high level. We also discuss the overflow probabilities and the expected number of customers at different loads, respectively.