• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.11B
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• pp.1038-1049
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• 2003

Exactly measuring traffic load is the basis for efficient traffic engineering. However, precise traffic measurement involves inspecting every packet traversing a lint resulting in significant overhead on routers with high-speed links. Sampling techniques are proposed as an alternative way to reduce the measurement overhead. But, since sampling inevitably accompany with error, there should be a way to control, or at least limit, the error for traffic engineering applications to work correctly. In this paper, we address the problem of bounding sampling error within a pre-specified tolerance level. We derive a relationship between the number of samples, the accuracy of estimation and the squared coefficient of variation of packet size distribution. Based on this relationship, we propose an adaptive random sampling technique that determines the minimum sampling probability adaptively according to traffic dynamics. Using real network traffic traces, we show that the proposed adaptive random sampling technique indeed produces the desired accuracy, while also yielding significant reduction in the amount of traffic samples.

• Journal of Korea Port Economic Association
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• v.27 no.1
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• pp.95-109
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• 2011

The aim of this study is to analyze the container terminal operation by considering the key factors that fluctuates the container traffic volume using the System Dynamics (SD) method. The target area of this study is the 'A' container terminal which is located in the Port of Incheon and the simulation period is from 2004 to 2020. As evaluation indexes for container terminal operation, three factors such as 'total sales', 'operating ratio of C/Y' and 'operating ratio of G/C' are selected, and as for the key factors of fluctuating container traffic volume, 'variation ratio of world trade', 'variation ratio of trade among three countries in North-East Asia' and 'variation ratio of won-dollar rate are used. As of 2020, the result of this study is that import-export container traffic volume increases almost 880,000TEU and total sales and operating ratio of G/C each reach 7.1 bilion won and 65 percent. No changes however in loadage and operating ratio of C/Y in 'A' container terminal are indicated. The reason is that capability of C/Y is exceeded. Therefore this study suggest that decision-makers of 'A' container terminal realize the importance of additional space of C/Y.

• 전자공학회논문지 IE
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• v.43 no.3
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• pp.41-48
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• 2006

In this paper, we propose a new active queue management (AQM) scheme by utilizing the predictability of the Internet traffic. The proposed scheme predicts future traffic input rate by using the auto-regressive (AR) time series model and determines the future congestion level by comparing the predicted input rate with the service rate. If the congestion is expected, the packet drop probability is dynamically adjusted to avoid the anticipated congestion level. Unlike the previous AQM schemes which use the queue length variation as the congestion measure, the proposed scheme uses the variation of the traffic input rate as the congestion measure. By predicting the network congestion level, the proposed scheme can adapt more rapidly to the changing network condition and stabilize the average queue length and its variation even if the traffic input level varies widely. Through ns-2 simulation study in varying network environments, we compare the performance among RED, Adaptive RED (ARED), REM, Predicted AQM (PAQM) and the proposed scheme in terms of average queue length and packet drop rate, and show that the proposed scheme is more adaptive to the varying network conditions and has shorter response time.

• Journal of Korean Society of Transportation
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• v.23 no.8 s.86
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• pp.139-145
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• 2005

`Influence Area` means the area that the traffic flow pattern of which is changed remarkably after the construction of highway facilities. The Influence area would be a significant criteria for demand forecasting and economic analysis. However existing methods for defining influence area such as O/D method, traffic volume variation method and rate of traffic volume variation method have no standard criteria. In this paper, some problems which existing methods have are analyzed and a new method travel time method - is introduced. Influence area can be induced as the area where the vehicles reach from starting traffic zone to ending zone to which 95 percentile vehicles want to travel. In addition, the value of standard criteria for defining influence ayes are induced via this method.

• The Journal of the Korea Contents Association
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• v.15 no.11
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• pp.582-590
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• 2015

Road type classification and K-factors are important role when design of number of lane. In this study not only classifies road type and estimating of K-factor but also economic evaluation tries for feasibility verification. Road type analysis results, time of day traffic volume variation, weekend-factor and vacation-factor are large in recreation roads. Weekday traffic volume and weekend traffic volume are similar patterns in provincial roads. AADT is high and time of day traffic volume variation is small in urban roads. In this study compares with economic analysis that designing of number of lane between KHCM's K-factor and this study K-factor. Economic analysis results, designed roads by this study's K-factor reduce cost about 4,708 hundred million won. So this study's K-factor is economical on provincial 4 lane roads.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.2
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• pp.236-247
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• 2002

We propose a cell－multiplexing scheme for the real－time communication service in ATM network and a new service discipline guarantee end-to-end delay based on pseudo-isochronous cell switching. The proposed scheme consists of two level frame hierarchy, upper and lower frame, which is used to assign the bandwidth and to guarantee the requested delay bound, respectively. Since the Proposed algorithm employs two level frame hierarchy, it can overcome the coupling problem which is inherent to the framing strategy It can be comparatively reduce the complexity, and still guarantee the diverse delay bounds of end-to-end. Besides, it consists of two components, traffic controller and scheduller, as the imput traffic description model and regulates the input traffic specification. The function of the traffic controller is to shape real -time traffic to have the same input pattern at every switch along the path. The end-to-end delay is bounded by the scheduller which can limit the delay variation without using per-session jitter controllers, and therefore it can decrease the required buffer size. The proposed algorithm can support the QoS's of non-real time traffic as well as those of real time traffic.

• Journal of KIISE:Software and Applications
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• v.31 no.11
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• pp.1534-1542
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• 2004

A novel vision-based scheme of extracting real-time traffic information parameters is presented. The method is based on a region classification followed by a spatio-temporal image analysis. The detection region images for each traffic lane are classified into one of the three categories: the road, the vehicle, and the shadow, using statistical and structural features. Misclassification in a frame is corrected by using temporally correlated features of vehicles in the spatio-temporal image. Since only local images of detection regions are processed, the real-time operation of more than 30 frames per second is realized without using dedicated parallel processors, while ensuring detection performance robust to the variation of weather conditions, shadows, and traffic load.

• Journal of Korean Society of Transportation
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• v.17 no.5
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• pp.69-78
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• 1999

This paper defines the reliable based route choice Principle and formulates the reliability based equilibrium traffic assignment using the Principle. The reliability is defined as the difference of travel demand and capacity using the interference theory of the system engineering. An efficient solution a1gorithm based on Frank-Wo1fe algolithm is Presented to calculate and compare the reliability based traffic assignment with conventional travel time based assignment using small and large scaled road networks. The results show that reliability based traffic assignment converges to equilibrium solution in a reasonable computing time. The equilibrium link flows between reliability and travel time based traffic assignment differ each other in the sense that reliability based assignment is assigned based on the maximum difference of travel demand and link capacity whilst travel time based is assigned on the shortest travel time.

• The Journal of the Korea Contents Association
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• v.8 no.6
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• pp.34-42
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• 2008

MAC(Medium Access Control) is demanded to provide end-to-end QoS(Quality of Service) for a variety of traffic in the wireless networks. When all the traffic is integrated in the channel, the main difficulty of the MAC protocol is how to efficiently support multi-class traffic in the limited bandwidth wireless channel. In this paper, we proposed the dynamic bandwidth slot method for improving QoS of the real time traffics. In this paper, we used in-band scheme to send dynamic parameter and considering buffer size and delay variation, we enabled 2 state bits to send to base station in mobile station. The proposed algorithm is to guarantee QoS of real time traffic and maximize transfer efficiency in wireless networks.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.4
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• pp.31-38
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• 2008

Under the recent situation that there increase the efforts to facilitate DFS(driver feedback sign) in school zones and children's protection areas caused by severity of traffic impact on children, the current study aims at predictively evaluating how and to what extent the reduced car speed is influential to the reduction of traffic accidents in elementary schools located in Buchon city by analyzing the velocity variation before and after DFS installation including its reduction ratio in traffic accidents as well as related literature survey. It, furthermore, aims at identifying applicable effectiveness in DFS operation for elementary schoolers in Buchon based on the data collected.