• Annual Conference of KIPS
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• 2007.05a
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• pp.1191-1194
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• 2007

이동 애드혹 네트워크 (MANET)는 기지국과 같은 인프라 없이 구성된 무선 네트워크로 멀티 홉 무선통신을 수행할 수 있다. MANET에서 경로 끊김이 발생하는 이유는 일반적으로 경로를 설정하고 있는 노드들의 이동이나 hidden terminal 과 같은 무선 채널 충돌 때문이다. 무선 채널 충돌처럼 노드들의 위상과 상관없이 패킷들의 충돌 때문에 경로 끊김이 발생하는 현상은 불필요한 경로 재설정이 유발된다. 그리고 이에 따른 제어 메시지의 과도한 생성은 전체 네트워크의 오버헤드를 증가시켜 성능 감소로 이어진다. 특히 일반적으로 MANET에서 사용하는 reactive 방식의 라우팅 프로토콜을 사용하는 네트워크에서는 더 많은 성능 감소가 일어나게 된다. 본 논문에서는 MANET의 이러한 불필요한 경로 재설정을 방지하여 자원을 보다 효율적으로 사용할 수 있는 노드 이동 감지 기법을 제안한다. 이 기법은 HELLO 메시지와 이웃 노드 테이블을 이용하여 무선 채널 충돌과 같은 현상을 예측하고 효율적으로 대처할 수 있게 한다. 성능 분석 결과, 본 논문에서 제안한 노드 이동 감지 기법이 기존 방법들에 비해 패킷 전송률과 라우팅 오버헤드 측면에서 우수한 성능 결과를 보였다.

• The Korean Journal of Applied Statistics
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• v.23 no.4
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• pp.705-713
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• 2010

Predicting survival from microarray data is not easy due to the problem of high dimensionality of data and the existence of censored observations. Also the limitation of individual gene analysis causes the shift of focus to the level of gene sets with functionally related genes. For developing a survival prediction model based on pathway information, the methods for selecting a supergene using principal component analysis and testing its significance for each pathway are discussed. Besides, the performance of gene filtering is compared.

• Journal of the military operations research society of Korea
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• v.36 no.3
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• pp.135-145
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• 2010

The submarine is very threatening and secretive weapon system that achieves missions under the sea. However, the submarine is faced with danger that can be attacked from the enemy when is detected by sensor or rose to the surface. This study will be planned optimal path to maximize the survival rate that considers submarine navigation capability in underwater and search activity of hostile warships. A mathematical programming model and a heuristic algorithm will be suggested in this study. The mathematical programming model is verified by using ILOG CPLEX. The submarine path, unit time(distance) of navigation, survival rate, and computation time is computed by using a heuristic algorithm.

• Journal of IKEEE
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• v.7 no.1 s.12
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• pp.80-87
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• 2003

This paper proposes a routing scheme for multi-hop LEO satellite networks with inter-satellite links aiming for reducing the number of link handovers while keeping the efficient use of network resource. The proposed routing scheme controls the link handovers by taking account of the deterministic LEO satellite system dynamics, geographical location of a ground terminal and statistic information of call duration. The performance of the proposed routing scheme has been evaluated and compared with previous routing schemes in terms of average number of link handovers during a call, the call blocking and dropping probability, and the network utilization.

• Journal of Advanced Navigation Technology
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• v.15 no.4
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• pp.536-542
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• 2011

This paper considers the performance of tightly-coupled GPS/INS integration using total-state UKF (Unscented Kalman Filter) for multipath error. In the city canyon there exists large multipath error and it may happen that GPS satellites are seen only three or less. For these situations simulations show that the performance of total-state UKF is better than that of EKF in the presence of multipath error. The total-state UKF shows robust performance for multipath error.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.358-360
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• 2004

웹 응용은 현재 가장 빠르게 성장하고 있고 사회에 미치는 영향이 큰 분야이다. 잘 못 동작하는 웹 응용은 사회적은 큰 손실이 될 수 있다. 이에 웹 응용의 검증 방법의 중요성이 대두되고 있다. 검증 방법으로는 코드 분석과 테스팅이 있다 허나 시장에 제품이 출시되는 시간이 매우 짧고, 관련 기술의 발달이 빠른 웹 응용 개발의 특성상 코드 분석은 왜 정확한 검증 결과를 얻을 수는 있으나 적절하다고는 할 수 없다 따라서 테스팅을 검증 방법으로 사용하게 된다. 그렇다고 해도, 테스팅에 들이는 시간과 노력이 코드 분석과 비슷하다면 이 또한 적절한 검증 방법이라고 할 수 없다. 테스팅의 비용을 줄여 전체적인 개발 비용을 줄이는 것이 필요하다 테스팅의 비용은 테스트 케이스를 수행하는 시간과 테스트 케이스로 생성, 분석하는 시간으로 측정 가능하다. 이 논문에서는 이 시간들을 줄이기 위해 전체 웹 응용의 경로 중 사용빈도가 높은 경로를 테스트 케이스로 타여 테스트 케이스 실행 시간을 줄이고, 각 페이지에 안는 입력 값으로 빈도가 높은 사용자 세션 정보를 이용하여 테스트 케이스의 생성을 자동으로 할 수 있게 하여 테스터가 직접 테스트 케이스를 생성하는 것보다 시간을 줄였다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.1 no.1
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• pp.52-57
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• 2002

A simulation tool for an optimal ATIS design and drivers' dynamic route choice behavior analysis is developed, which is applicable to urban networks. Due to the difficulty to make drivers feel the time pressure according to traffic conditions, current SP questionnaire survey type surveys have a limitation to capture correct driver reactions to real-time traffic Information provision. The simulator Is a web-based upgraded version, named WATiSim (Web-based ATIS Simulator), to quickly perform a wide population survey with a minimal cost using INTERNET Furthermore, the time pressure issue is lessened by its interface and simulation modules. After WATiSim mimicked a VMS based ATIS in a partial network of Seoul Metropolitan, reactions of drivers to various traffic conditions were surveyed through INTERNET and analyzed using a logit model. Drivers under the ATIS environment clearly understood the provided traffic information, and their reactions were closely related to traffic conditions, scheduled delay, trip purposes as well as toll charge if any.

• Journal of KIISE:Information Networking
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• v.36 no.3
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• pp.204-211
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• 2009

Proxy Mobile IPv6(PMIPv6) is that network-based mobility management protocol that network supports mobile node's mobility on behalf of the Mobile Node(MN). In PMIPv6 network, data packets from a Correspondent Node(CN) to a MN will always traverse the MN's Local Mobility Anchor(LMA). Even though, CN and MN might be located close to each other or within the same PMIPv6 domain. To solve this problem, several PMIPv6 Route Optimization(RO) schemes have been proposed. However, these RO schemes may result in a high signaling cost when MN moves frequently between MAGs. For this reason, we propose an adaptive route optimization(ARO) scheme. We analyze the performance of the ARO. Analytical results indicate that the ARO outperforms previous schemes in terms of signaling overhead.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.3
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• pp.79-85
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• 2014

For the successful operation of unmanned ground vehicles(UGVs), optimal path planning should be considered with trafficability analysis, threat analysis, and so on. From among these, trafficability analysis is immensely important for safeness of UGVs especially in the case of driving the off-road such as unpaved road, grassland, and open fields. Geographical information has a pivotal role in extracting data and measuring cost for specified regions of interest. In this paper, we review possibilities to apply Land Cover Map(LCM) as a new, fundamental source and propose a new generation method of trafficability analysis map for optimal path planning of UGV. The simulation results show that the proposed method significantly improve the previous method by applying LCM either alone or in combination with the other GIS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.4
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• pp.781-787
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• 2007

Network Mobility (NEMO) basic support protocol doesn't execute the process of route optimization and has not presented the particular security mechanism in other blocks except hi-directional tunnel between Mobile Router (MR) and its Home Agent (HA). Therefore in this paper we process secure route optimization courses through authenticated binding update protocol between MR and its Correspondent Node (CN) and the protocol of the competency of mandate between MR and its Mobile Network Node (MNN); its block also uses an bi-directional tunnel as the block between MR and its HA. The address of each node are generated by the way of Cryptographically Generated Address (CGA) for proving the ownership of address. Finally we analyze the robustness of proposed protocol using security requirements of MIPv6 and existing attacks and the efficiency of this protocol using the connectivity recovery and end-to-end packet transmission delay time.