• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1197-1198
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• 2008

The purpose of the Air Traffic Control(ATC) system is to provide a safe, efficient flow of air traffic from origin to destination. Therefor, it is important to reduce the operational errors. Most of errors occurs from controllers. So, we suggest the human machine interface scheme for Air Traffic Control system.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1164-1169
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• 2006

본 논문은 차량운행경로문제(Vehicle Routing Problem)의 기본적인 정보가 되는 Origin-Destination (OD) Matrix 의 생성에 관한 문제를 다룬다. OD Matrix 를 만들기 위해서는 몇 개의 지점으로부터 몇 개의 지점(some-to-some)까지의 최단 거리를 계산해야 한다. 이를 위해 Dijkstra 알고리듬과 같은 one-to-all 알고리듬을 반복하여 사용할 수 있고 Floyd-Washall 알고리듬과 같은 all-to-all 알고리듬을 사용할 수 있으며 some-to-some 을 위해 고안된 알고리듬을 사용할 수 있다. 본 연구에서는 이러한 알고리듬들이 실제 도로 네트워크의 OD Matrix 를 생성할 때 어떤 성능을 보이는지 비교 분석한다.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.1073-1083
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• 2005

Since the operation of subway line 1 between Seoul and Cheongryangri stations in 1974, the rail length and riderships have been increased during the three decades. Furthermore, it was a remarkable increase of line length between 1995 and 2004 by the operation of Lines 5, 6, 7, and 8 within Seoul metropolitan area. This study reports the variations of riderships by the changing urban spatial structure. According to analysis results by station-to-station origin-destination trip tables, there were increasing ridership changes in new stations within new subcenters, while there were little ridership changes in old stations within Seoul and existing subcenters. The levels of competition between the existing and new lines brought about the difference of ridership changes.

• Journal of Korean Society of Rural Planning
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• v.22 no.1
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• pp.49-56
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• 2016

Throughout the economic development era of Korea, migration occurred within a spatial hierarchy, with upward flows from rural areas to urban. The concept of step migration is a typical theory to explain these upward migration flows. Recent migration data and trends, however, indicate that migration-pattern regime shows strongly opposite-direction flows, with many of the major migration flowing downward on this national-spatial hierarchy, away from urban areas. In this study, we examine the most recent structure of migration flows up and down within the national-spatial hierarchy. We define seven tiers to tabulate origin-destination migration flows from population density of local administrative districts for the period 2001-2014, and then analyze the migration patterns between the tiers over time. The results show differentiated patterns of migration within the national-spatial hierarchy over time including specific states of migrants' life cycles.

• Journal of Navigation and Port Research
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• v.28 no.4
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• pp.277-284
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• 2004

This paper tries to draw some implications for Korean seaports in terms of management and development of ports with respect to attracting more transshipment container cargoes. For this the results of the Origin-Destination(O-D) analysis between major Korean ports and top 20 Chinese ports were presented. They also contained the O-D analysis between Chinese major ports and their inland hinterlands.

• Journal of Korea Port Economic Association
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• v.22 no.1
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• pp.175-198
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• 2006

This paper presents a network capacity model that can be used as an analytical tool for strategic planning and resource allocation for multimodal transportation systems. In the context of freight transportation, the multimodal network capacity problem (MNCP) is formulated as a mathematical model of nonlinear bi-level optimization problem. Given network configuration and freight demand for multiple origin-destination pairs, the MNCP model is designed to determine the maximum flow that the network can accommodate. To solve the MNCP, a heuristic solution algorithm is developed on the basis of a linear approximation method. A hypothetical exercise shows that the MNCP model and solution algorithm can be successfully implemented and applied to not only estimate the capacity of multimodal network, but also to identify the capacity gaps over all individual facilities in the network, including intermodal facilities. Transportation agencies and planners would benefit from the MNCP model in identifying investment priorities and thus developing sustainable transportation systems in a manner that considers all feasible modes as well as low-cost capacity improvements.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.426-433
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• 2002

This paper deals with an offline routing problem, which can be used as an explicit routing procedure in MPLS(Multiprotocol Label Switching) network, for traffic engineering. This problem is formulated as an MIP(Mixed Integer Programming) with the objective function which is to minimize the sum of the maximum link utilization for load balancing (link utilization) and the routing cost. Constraints arc composed of link capacity restriction and demand requirement that has origin-destination pair, bandwidth requirement and hop restriction. The problem is proved to be NP-hard so that the Lagrangean relaxation method is applied to propose a Lagrangean heuristic. To test the effectiveness & efficiency of the proposed algorithm, computational experiments are performed with numerical instances. The experiment results show that the proposed algorithm solves the problem within a reasonable time.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.10a
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• pp.243-245
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• 2015

항만간의 물동량 확보 경쟁은 국외 항만간 뿐만 아니라 국내 항만간에도 치열하게 이루어지고 있다. 이와 같은 상황에서 항만 물동량 확보를 위한 경쟁력 강화의 방안 중 하나로 O-D 분석(Origin-Destination, 기종점분석)을 통한 교역구조와 교역품목 분석을 고려 할 수 있다. 본 연구는 최근 10년간 국내 주요 4대 항만에 대한 전체 국내외 교역구조와 지역과 항만별 교역품목 분석하여 항만 경쟁력 강화를 위한 방안을 제시하고자 하였다. 연구의 결과는 국내 주요 항만은 국내 지역과 국외 지역, 항만별 특색을 가진 교역 구조를 나타냈으며, 교역품목에서도 지역별, 항만별 특색을 보이는 것으로 분석되었다. 본 연구의 결과는 항만 물동량 확보를 위한 마케팅 대상 지역과 품목에 대해 활용이 가능할 것이다.

• International Journal of Internet, Broadcasting and Communication
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• v.7 no.1
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• pp.23-29
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• 2015

Energy constraints of wireless sensor networks are an important challenge. Data Transmission requires energy. Distance between origin and destination has an important role in energy consumption. In addition, the location of base station has a large impact on energy consumption and a specific method not proposed for it. In addition, a obtain model for location of base station proposed. Also a model for distributed clustering is presented by cluster heads. Eventually, a combination of discussed ideas is proposed to improve the energy consumption. The proposed ideas have been implemented over the LEACH-C protocol. Evaluation results show that the proposed methods have a better performance in energy consumption and lifetime of the network in comparison with similar methods.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.1
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• pp.114-120
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• 2012

Eco-driving technique for electric vehicles (EVs) is investigated in this paper. Many findings on EVs have been reported; however, they did not deal with eco-driving from the viewpoint of theoretical study. The authors have developed an energy-saving driving technique - the so-called "eco-driving" technique based on dynamic programming (DP). Optimal speed profile of an EV, which minimizes the amount of total energy consumption, was determined under fixed origin and destination, running time, and track conditions. DP algorithm can deal with such complicated conditions and can also derive the optimal solution. Using the proposed method, simulations were run for some cases. In particular, the author ran simulations for the case of a gradient road with a traffic signal. The optimization model was solved with MATLAB.