• Convergence Security Journal
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• v.12 no.6
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• pp.25-30
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• 2012

As the network composed of numerous sensor nodes, sensor network conducts the function of sensing the surrounding information by sensor and of the sensed information. Our military has also developed ICT(Information and Communication Technology) along with the methods for effective war by sharing smooth information of battlefield resources through network with each object. In this paper, a sensor network is clustered in advance and a cluster header (CH) is elected for clusters. Before deployment, a certificate is provided between the BS and the sensor nodes, and after clustering, authentication is done between the BS and the sensor nodes. Moreover, inter-CH authentication technique is used to allow active response to destruction or replacement of sensor nodes. Also, because authentication is done twice, higher level of security can be provided.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.37-40
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• 2019

On this paper, we show the way of forming graph data structure via setting an edge between Korean actors if they appeared in the same movie. From this graph, we calculate the 'centralities' (which declared on this paper) for each actor, then examine distribution by ranking the actors of the centralities and analyze the change of the actor who is/was center on the graph by years. Finally, we suggest the way that sets the numerically Range limits on social group.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.620-622
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• 2009

기존의 지능형 홈은 주거환경에서의 사용자의 편의성이 중심이 된 IT기술 기반의 홈 네트워크 중심 기술이었기 때문에 에너지 절감 측면에서의 기술 적용은 거의 이루어지지 않았으며 적용된 기술 또한 기술적 수준이 매우 미흡하였다. 본 논문에서는 이러한 주택 환경에서 에너지 절감 효율을 끌어올리기 위한 요소 인프라 기술을 유도해 내기 위해 실제 사용자의 생활 행위 패턴을 에너지 절감을 위한 구성 요소로 파악하여 실제 이러한 생활 패턴을 정형화 할 수 있는 데이터 베이스를 구축하기 위한 할 수 있는 테스트 모델을 셋업하였다. 이를 위해 복도, 출입구 그리고 현재 근무 중인 테이블에 조도 센서와 인체 감지 센서를 설치하였는데 조도 센서와 인체감지 센서는 하나의 그룹을 이루며 생활패턴을 파악하고 조도 값에 따라 실내등을 소등할 수 있도록 한다. 개개의 센서 노드에서 수집된 센싱 데이터는 브릿지에 있는 베이스 노드로 수집되고 이는 인터넷망을 통해 서버로 전달되어 DB 구축되어 진다. 이러한 시뮬레이션 테스트 모델을 통해 에너지 소비 상태를 파악하고 정형화 함으로써 에너지 절감을 위한 기술 구현이 가능해 진다.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.7
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• pp.275-288
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• 2019

In this paper, we consider a rumor source inference problem when sufficiently many nodes heard the rumor in the network. This is an important problem because information spread in networks is fast in many real-world phenomena such as diffusion of a new technology, computer virus/spam infection in the internet, and tweeting and retweeting of popular topics and some of this information is harmful to other nodes. This problem has been much studied, where it has been shown that the detection probability cannot be beyond 31% even for regular trees if the number of infected nodes is sufficiently large. Motivated by this, we study the impact of query that is asking some additional question to the candidate nodes of the source and propose budget assignment algorithms of a query when the network administrator has a finite budget. We perform various simulations for the proposed method and obtain the detection probability that outperforms to the existing prior works.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.7
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• pp.858-863
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• 2005

Sensor network is subject to novel problems and constraints because it is composed of thousands of tiny devices with very limited resources. The large number of motes in a sensor network means that there will be some failing nodes owing to the lack of battery in sensor nodes. Therefore, it is imperative to save the energy as much as possible. In this work, we propose energy efficient routing algorithm which is based on directed diffusion scheme. In the proposed scheme, some overloads required for reinforcing the gradient path can be effectively eliminated. Furthermore, in order to verify the usefulness of the proposed algorithm, several simulations are executed.

• Journal of Korea Multimedia Society
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• v.11 no.5
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• pp.661-672
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• 2008

Mobile Ad-hoc NETwork is a kind of self-controlled network composed only of mobile hosts. Since its range of use is gradually expanding into various sections applicable to practical lives, active researches are being conducted on it. However, as it depends on cooperation of nodes composing the entire network, due to weakness of wireless link and lack of its central infrastructure, so it is exposed to more serious risk than general network in security. Therefore, this paper proposes Cluster-Based Dynamic Authentication that enables only reliable nodes to participate in communication, by solving lack of centralized infrastructure, using hierarchical Mobile Ad hoc NETwork structure based on cluster, and by complementing security weakness through mutual authentication between hierarchical nodes. Simulation shows that the proposed scheme can complement security weakness of Mobile Ad hoc NETwork and that it is more adequate in reliability and expandability than the existing schemes.

• The Journal of the Korea Contents Association
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• v.14 no.9
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• pp.529-537
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• 2014

To establish a foundation to objectively interpret Chosun history, we construct people network of the Chosun dynasty. The network shows scale free network properties as if most social networks do. The people network is composed of 1,379 nodes and 3,874 links and its diameter is 14. To analysis of the network dynamics, whole network that is composed of 27 king networks were constructed by adding the first king, Taejo network to the second king, Jeongjong network and then continuously adding the next king networks. Interestingly, betweenness and closeness centralities were gradually decreased but stress centrality was drastically increased. These results indicate that information flow is gradually slowing and hub node position is more centrally oriented as growing the network. To elucidate key persons from the network, k-core and MCODE algorithms that can extract core or module structures from whole network were employed. It is a possible to obtain new insight and hidden information by analyzing network dynamics. Due to lack of the dynamic interacting data, there is a limit for network dynamic research. In spite of using concise data, this research provides us a possibility that annals of the Chosun dynasty are very useful historical data for analyzing network dynamics.

• The KIPS Transactions:PartC
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• v.15C no.6
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• pp.513-522
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• 2008

Efficient data dissemination is one of the important subjects for sensor networks. High accessibility of the sensed data can be kept by deploying the data centric storage approach in which data is stored over the nodes in the sensor network itself rather than external storages or systems. The advantage of this approach is its direct accessibility in a real-time without the severe burden on delay and power dissipation on the data path to the external storages or systems. However, if the queries from many users are concentrated to the few nodes with data, then the response time could be increased and it could lead to the reduction of network life time by rapid energy dissipation caused by concentrated network load. In this paper, we propose a adaptive data centric storage scheme based on proxy trajectory (APT) mechanism. We highlight the data centric storage mechanism by taking account of supporting large number of users, and make it feasible to provide high-performance accessibility when a non-uniform traffic pattern is offered. Storing data around the localized users by considering spatial data-access locality, the proxy trajectory of APT provides fast response for the users. The trajectory, furthermore, may help the mobile users to roams freely within the area they dwell.

• Proceedings of the Korean Society of Computer Information Conference
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• 2008.06a
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• pp.149-154
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• 2008

FCM 기반 RBF 네트워크는 서로 다른 학습 구조가 결합된 혼합형 모델로서, 입력층과 중간층의 학습 구조는 FCM 알고리즘을 적용하고, 중간층과 출력층 사이의 학습 구조는 Max_Min 신경망을 적용한다. 입력층과 중간층의 학습시 입력벡터와 중간층의 노드중에서 중심과 입력벡터간의 가장 가까운 노드를 승자 노드로 선택하여 출력층으로 전달한다. 그리고 중간층과 출력층 사이의 학습 구조는 Max_Min 신경망을 적용하여 중간층의 승자 뉴런이 출력층의 입력벡터로 적용한다. 하지만 많은 패턴이 입력벡터로 제시될 경우 학습 성능이 저하되는 단점이 있다. 따라서 본 논문에서는 중간층과 출력층의 학습 구조인 Max_Min 알고리즘의 학습 성능을 개선시키기 위해 퍼지 제어시스템을 이용하여 학습률을 동적으로 조정하는 퍼지 제어 기법을 이용한 FCM 기반 RBF 네트워크를 제안한다. 제안된 방법의 학습 성능을 평가하기 위하여 컨테이너 영상에서 추출한 숫자, 영문 식별자를 학습 데이터로 적용한 결과, 기존의 ART2 기반 RBF 네트워크보다 학습 시간이 적게 소요되고, 학습의 수렴성이 개선된 것을 확인하였다.

• Information and Communications Magazine
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• v.32 no.7
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• pp.9-16
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• 2015

본고에서는 Transport SDN의 고확장성과 네트워크 장애를 신속하게 복구하기 위한 고가용성을 제공하는 SDN 컨트롤러 구조와 데이터 플레인 장애 복구 기술 동향을 소개한다. SDN 컨트롤러 기술에 대해서는 최근 많은 관심을 받고 있는 오픈소스 프레임워크 기반의 SDN 컨트롤러를 중심으로 확장성 및 고가용성 기술 동향을 살펴본다. 그리고 데이터 플레인에서 노드 및 경로 장애 발생 시 신속하게 경로를 복구하기 위한 보호기술과 복구기술 동향을 소개한다.