• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.8C
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• pp.729-740
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• 2002

This paper studies the issues arising in the virtual topology reconfiguration phase of Multi-wavelength Routed Optical Networks. This reconfiguration process means to change the virtual topology in response to the changing traffic patterns in the higher layer. We formulate the optimal reconfiguration policy as a multi-stage decision-making problem to maximize the expected reward and cost function over an infinite horizon. Then we propose a new heuristic algorithm based on node-exchange to reconfigure the virtual topology to meet the traffic requirement. To counter the continual approximation problem brought by heuristic approach, we take the traffic prediction into consideration. We further propose a new heuristic reconfiguration algorithm called Prediction based Multi-stage Reconfiguration approach to realize the optimal reconfiguration policy based on predicted traffic. Simulation results show that our reconfiguration policy significantly outperforms the conventional one, while the required physical resources are limited.

• The Korean Journal of Air & Space Law and Policy
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• v.20 no.1
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• pp.255-272
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• 2005

This study was conducted to present the adaquate guidelines necessary in decision making processes regarding air traffic management as well as airspace management in the national airspace system. It encompasses the overall advanced air traffic management initiatives, domestic air traffic congestion and resolution method as well.

• Electronics and Telecommunications Trends
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• v.34 no.3
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• pp.106-113
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• 2019

Mobile traffic is one of the most important indexes of the growth of the mobile communications market, and it has a close relationship with subscribers' service usage patterns, frequency demand and supply, network management, and information communication policy. The purpose of this paper is to understand mobile data usage in Korea and to suggest the optimal steps for establishing the frequency supply and demand system by researching the traffic trends that reflect the characteristics of radio resources in the mobile communications field. To achieve this goal, attempts were made to increase the possibility of policy use by analyzing and forecasting mobile traffic trends, and to improve the accuracy of the research through the verification of the existing prediction results. The paper ends with a discussion of the necessity of a frequency management system based on data science.

• Journal of Korean Society of Transportation
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• v.26 no.2
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• pp.69-78
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• 2008

Tour traffic takes largely place at certain limited period of time so that it is desirable to adopt some kind of software-typed approaches like the introduction of a new traffic system rather than hardware-typed ones of extension or construction of roads, and which naturally leads to the need of establishing a new tour traffic policy that makes the most profit at the lowest cost. In this research, I studied cognitive characteristics of traffic congestion of tour traffic and non-tour traffic and constructed a transfer traffic-choice behavior model for the introduction of transfer-traffic system and examined its influence factors. As a result, it is revealed that respondents feel much more the cognitive strength of traffic congestion at tourist resorts than they feel usually at non-tourist sites. That means the necessity of the introduction of the policy that enhances access to tourist resorts. In closing, through the transfer-traffic choice behavior model, I identified the fact that the introduction of transfer-traffic system could convert the trend of highly frequent use of passenger cars on tourism season into public transportation use, which shows that relevant policy-makers ultimately need to make a comprehensive policy considering traffic aspect in revitalizing tour resorts.

• Journal of Korean Society of Transportation
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• v.36 no.2
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• pp.112-128
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• 2018

We are implementing pedestrian priority zone policy to certain districts to reduce greenhouse gas and to develop eco-friendly city which has more focus on pedestrians' walking environment. This policy has contributed to citizens' satisfaction level with improved public transportation service as well as more spacious streets for walk. Despite highly positive influence of pedestrian priority zone policy to the walking environment, we need to anticipate the impact of this to traffic environment as it may have bad effect to the overall traffic flow around the zone where the policy is implemented. This research has analyzed the change of characteristics of traffic accidents around the eco-traffic area of Hang-Gung dong, Suwon city, to understand impact of the pedestrian priority zone policy to the traffic surroundings, with pre-post analysis methodology. As a result, number of accidents related to pedestrians showed decrease as pedestrian priority zone is designed operated with focus to pedestrians. But accidents related illegal U-turn and violation of the traffic signal showed (significant) increase as there was a restriction of turns and decrease of overall traffic speed. To prevent the accidents above, we need to notice drivers to pay special attention before the pedestrian priority zone event, and information from this research should be given to the drivers through safety signs and mobile application at the place near to the event.

• Korean System Dynamics Review
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• v.4 no.2
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• pp.131-151
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• 2003

Traffic congestion stems from the widespread desires of people to purse certain goals that inevitably overload existing roads every day. he a transportation policy, congestion toll system has been implemented in Seoul, since 1996. The growing concerns on whether the system would achieve sustained results in the future motivated us to investigate the effectiveness of this policy. Developing and running the congestion toll simulation model, we find that this policy is not an effective policy in the long m. The paper indicates the power of system dynamics approach as a tool for evaluating complex policy like a congestion toll, and suggest that city transportation policy maker should approach the problem with systems thinking and analyze the effectiveness of policy on the basis of understanding the dynamic relationships among subsystems.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1931-1936
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• 2007

Demand forecasting for railroad traffic is fairly important to establish future policy and plan. The future demand of railroad traffic can be predicted by analyzing the demand of air, marine and bus traffic which influence the demand of railroad traffic. In this study, forecasting the demand of railroad traffic is implemented through neural network using the demand of air, marine and bus traffic. Estimate accuracy of the demand of railroad traffic was shown about 84% through neural net model proposed.

• Journal of Digital Convergence
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• v.16 no.10
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• pp.213-222
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• 2018

This study was conducted to derive the traffic accident risk index through the recognition of the elderly driver's driving pattern to reduce the traffic accident rate of elderly drivers and to reflect them in the renewal and return policy of driver's license accordingly. First, the traffic accident risk index is defined by analyzing the behavioral characteristics of older drivers to derive the major factors that lead to traffic accidents. Second, we present a method to measure the traffic accident risk index from the driving pattern of the elderly through the smart-phone, the camera and the distance sensor attached to the car. Finally, we derive three thresholds by computer simulation and determine the accident risk from the measured traffic accident risk index as four steps and suggest ways to ensure safe driving of older drivers. It is required to objectively assess the driving ability of an aged driver in accordance with the proposed method, and to induce the driver to reset the driver's license renewal cycle and voluntarily return the driver's license to minimize social costs due to increased traffic accidents.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4B
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• pp.344-348
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• 2006

This paper proposes a QoS policy for cellular networks which support the policy based network management scheme. The policy exploits the existing underlying DiffServ mechanism and the priority-based packet scheduler in order to provide the packets with different handling priority depending on their belonging traffic classes. The simulation results reveals the effectiveness of the proposed policy under the network congestion; it shows that the goodput of the real-time traffic is not affected at all in spite of the surge of the non real-time traffic.

• Journal of Korean Society of Transportation
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• v.26 no.4
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• pp.205-215
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• 2008

As static traffic assignment has reached its limitation with ITS policy applications and due to the increase of interest in studies of ITS policies since the late 1980's, dynamic traffic assignment has been considered a tool to overcome such limitations. This study used the Dynameq program, which simulates route choice behavior by macroscopic modeling and dynamic network loading and traffic flow by microscopic modeling in consideration of the feasibility of the analysis of practical traffic policy. The essence of this study is to evaluate the feasibility for analysis in practical transportation policy of using the dynamic traffic assignment technique. The study involves the verification of the values estimated from the dynamic traffic assignment with South Korea's expressway network and dynamic O/D data by comparing results with observed link traffic volumes. This study used dynamic O/D data between each toll booth, which can be accurately obtained from the highway Toll Collection System. Then, as an example of its application, exclusive bus-lane policies were analyzed with the dynamic traffic assignment model while considering hourly variations.