• Journal of Korea Multimedia Society
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• v.9 no.3
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• pp.333-341
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• 2006

Recently, Random Constant worm is increasing The worm retards the availability of the overall network by exhausting resources such as CPU resource and network bandwidth, and damages to an uninfected system as well as an infected system. This paper analyzes the Power-Law network which possesses the preferential characteristics to restrain the worm from spreading. Moreover, this paper suggests the model which dynamically controls the spread of the worm using information about depth distribution of the delivery node which can be seen commonly in such network. It has also verified that the load for each node was minimized at the optimal depth to effectively restrain the spread of the worm by a simulation.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.355-357
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• 2004

센서 네트워크는 계산 용량과 에너지가 제한적이라는 특성을 가지며 그 결과 시스템의 보안관련 요구를 만족시키기 위해 기존 네트워크의 방식을 적용할 수 없다. 본 논문에서는 센서 네트워크의 보안을 위하여 기존 다층화 된 보안구조에서 사용되는 키 분배 방식을 개선함으로써 에너지 소모를 크게 증가시키지 않으며 전체 네트워크의 신뢰도를 개선할 수 있는 방법을 제안한다. 랜덤 그래프의 성질을 이용한 키 분배 방식으로 이를 이용하여 비교적 낮은 에너지 소모와 개선된 신뢰성을 적절히 제공할 수 있다.

• The Magazine of the IEIE
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• v.42 no.5
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• pp.44-55
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• 2015

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.444-446
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• 2021

MANETs(Mobile Ad-hoc Networks) are composed of mobile nodes that are not subordinate to fixed networks and have the feature that can form their own networks. they are used in various fields for specific goals. The mobility model in MANET can be applied in various ways depending on the purpose of usage. The random mobility model has the advantage of being simple and easy to implement, so it is being used the most. In a MANET, it is assumed that each node moves independently. The random movement model is a good model for expressing this independence of each node. However, it is insufficient to express the characteristics of all nodes with only random properties of individual nodes. This paper limits the stochastic mobility model applicable in MANET. we compare the proposed stochastic mobility model and the random mobility model. We confirm that the proposed mobility model is applied to the routing protocol to show improved characteristics in terms of energy consumption efficiency.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.5
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• pp.1-7
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• 2014

Distance based mobility management schemes have been considered as a major issue in the wireless network research area. Accordingly, many efforts have been made to analyze them numerically with suitable mobility models. In particular, bidirectional random walk model has been employed frequently due to its simplicity. Nevertheless, the exact equations are not presented so far. In this paper, we provide the exact equations regarding the bidirectional random walk model, which is very useful for the analysis of the distance based mobility management schemes.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.2
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• pp.194-200
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• 2002

A method for simulating flow of extremely low Reynolds number in a vortex-in-cell (VIC) was studied. The viscous diffusion was represented by the random walk method. The validity of this method was proven by applying it to the flows passing over a fence placed vertically at an extremely low Reynolds number. The effects of parameters of the VIC method on the random walk method, such as the number of point vortices, the mesh density and the time increment, were investigated by numerical analysis using a one-dimensional diffusion equation. Changes in the relative error of vorticity depending on those parameters were clarified.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.96-97
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• 2020

랜덤워크 기반 노드 랭킹 방식 중 하나인 RWR(Random Walk with Restart) 기법은 희소행렬 벡터 곱셈 연산과 벡터 간의 합 연산을 반복적으로 수행하며, RWR 의 수행 시간은 희소행렬 벡터 곱셈 연산 방법에 큰 영향을 받는다. 본 논문에서는 CSR5(Compressed Sparse Row 5) 기반 희소행렬 벡터 곱셈 방식과 CSR-vector 기반 희소행렬 곱셈 방식을 채택한 GPU 기반 RWR 기법 간의 비교 실험을 수행한다. 실험을 통해 데이터 셋의 특징에 따른 RWR 의 성능 차이를 분석하고, 적합한 희소행렬 벡터 곱셈 방안 선택에 관한 가이드라인을 제안한다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.502-504
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• 2004

이동성이 중요시되는 네트워크에서 특정 프로토콜의 성능 평가를 위해서는 노드의 이동패턴을 정확하게 표현할 수 있는 Mobility Model이 필요하다. 노드의 연속적인 이동패턴을 필요로 하는 Mobile Ad-hoc 네트워크를 위해선 Markov process 기반의 Gauss-Markov Mobility Model이 적절하다. 그러나 맵의 엣지 부근에서 노드 이동의 부적절한 처리로 인해, 기존의 Gauss-Markov Model은 편중된 이동 패턴을 야기한다. 본 논문은 엣지 부근의 평균 이동각도를 랜덤하게 조정함으로써 기존의 모델이 가진 문제를 해결하고, 시뮬레이션을 통해서 이를 검증한다.

• The Korean Journal of Applied Statistics
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• v.30 no.3
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• pp.403-415
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• 2017

In this paper, we investigate cosponsorship networks found in the 17th National Assembly of Republic of Korea. New legislation should be sponsored by at least 10 legislators including one main sponsor. Cosponsorship networks can be constructed, using directional links from cosponsors of legislation to its main sponsor; subsequently, these networks indicate the social relationships among the legislators. We apply Exponential Random Graph Model (ERGM) for valued networks to capture structural properties and the covariate effects of networks. We find the effect of the same party has the greatest influence on the composition of the network. Mutuality also plays an important role in the cosponsorship network; in addition, the effect of the number of elections won by a legislator has a small but significant influence.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.34 no.6
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• pp.30-35
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• 2016