• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.5
• /
• pp.887-898
• /
• 2009

Conventional routing protocols proposed for wireless sensor networks (WSNs) cannot fully accommodate the characteristics of WSNs. In particular, although it is possible to largely obtain benefits in the solution of energy consumption and global identification problems through applying position information, there are few protocols that actively apply such position information. In the case of geographical and energy aware routing (GEAR) that is a typical algorithm, which uses position information, it does not fully represent the characteristics of WSNs because it is limited to forward query messages and assumed as fixed network environments. The routing protocols proposed in this paper defines the direction of data, which is routed based on the position information of individual and target nodes, in which each node configures its next hop based on this direction and routes signals. Because it performs data-centric routing using position information, it does not require certain global identifications in order to verify individual nodes and is able to avoid unnecessary energy consumption due to the forwarding of packets by defining its direction.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.10a
• /
• pp.510-512
• /
• 2013

본 논문에서는 이동 에드 혹 네트워크(Mobile Ad-hoc network: MANET)에서의 상황인식 기반의 에너지 스케쥴링 기법인 ESWC(Energy Scheduling Weighted-value Control) 알고리즘을 제안한다. 기존 MANET에서 노드의 에너지를 관리하기 위한 여러 가지의 방법들이 제안 되고 있다. 특히 이동노드들의 경우 이동성에 따라 에너지 소모율이 다르며, 이때 상호 노드간 전송하는 데이터와 상호 위치에 따라 에너지 소모율은 다르게 된다. 본 논문에서는 계층적 클러스터 단위의 동적인 토폴로지에서 전송 거리와 전송 데이터의 패킷량이 어떠한 상호관계에 따라 노드의 소모 에너지에 미치는 영향이 있는지를 분석한다. ESWC에서 도출된 에너지의 가중치 결과는 최종적으로 전송 경로에 있어 에너지 소모율을 분석하여 네트워크상에서 전체적인 노드의 라이프타임을 향상 시킬 수 있다. 본 연구의 주어진 모의실험환경에서 노드의 방향성 및 시간에 따른 이동성을 반영함으로써 에너지 효율적인 클러스터링 및 라우팅 경로 알고리즘이 제공되어 네트워크의 최적화된 에너지 소모 결과를 보여주었다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2018.10a
• /
• pp.181-184
• /
• 2018

최근 주목 받고 있는 소프트웨어 정의 네트워크(SDN: Software-Defined Networks)는 기존 네트워크 운용의 비효율성과 복잡성을 근본적으로 해결하기 위해 등장한 개방형 네트워크 인프라이다. SDN 시스템이 점차 상용화, 개방화 되는 시점에서, 내재되어있는 보안적 위협을 줄이기 위하여 효율적이고 자동화된 취약점 탐지의 필요성이 대두되고 있다. 본 논문에서는 자동화된 소프트웨어 테스트 기법 중 하나인 퍼즈테스팅이 SDN에 적용되어야 할 이유를 살펴보고자 한다. 또한, 기존에 관련된 연구의 분석을 통해 현재 학계의 연구동향을 파악하고 앞으로의 연구 방향성을 제시한다.

• Journal of Korean Library and Information Science Society
• /
• v.42 no.2
• /
• pp.85-103
• /
• 2011

Bibliographic Network has been a goal about not only to support resource sharing within libraries but also to pursue economic efficiency of cataloging. But nowadays, as resources in diverse media and format have been poured out, printed resources based union catalog should change to new resources finding system which include diverse type of resources. This study analyzes changing factors of bibliographic network and strategies for LC, NII, OCLC, NLA who try to turn over a new service. Finally basis on these findings, suggest task for Korean new generation bibliographic network service which is focused on introducing new collaborating model and developing new resource finding system.

• The Journal of the Korea Contents Association
• /
• v.18 no.9
• /
• pp.433-440
• /
• 2018

I investigated whether network structure of legislators affects legislative performance in a cosponsorship network. I presented the theoretical basis with network closure and structural holes, and analyzed the network in the 19th National Assembly of Republic of Korea. In the directed and weighted network, each tie means that cosponsors support the bill sponsors proposed. The performance was measured by the number of initiatives and the ratio of reflected legislation, and the network structure was measured by size, density, hierarchy, and constraint. I found that the legislators with brokerage structure have a lot of initiatives in making connection with many legislators in various groups and the legislators with hierarchical structure have the higher ratio of reflected legislation with the continuous and strong support from the members of their group. I also found that the network of ruling party lawmaker is more hierarchical than the network of opposition lawmaker.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.1
• /
• pp.24-29
• /
• 2011

Comparing conventional one-way relaying, two-way relaying scheme with network coding can achieve high throughput by reducing the transmission time. Coded cooperation protocol, which is a algorithm that uses coding on physical layer, can achieve high reliability. In this paper, we propose coded cooperation protocol over two-way relay network. Simulation results show proposed protocol has better performance in terms of reliability and throughput compare with conventional amplify and forward protocol. Also, with same throughput, proposed protocol has better performance in terms of reliability compare with the conventional hybrid decoded and forward protocol.

• The Journal of the Korea Contents Association
• /
• v.7 no.4
• /
• pp.39-48
• /
• 2007

Ad hoc network is a wireless network without fixed base stations or any wired backbone infrastructure. In the DUDMAC protocol, ORTS and OCTS in control channel solve the problem of deafness and DDATA and DACK in data channel improve spatial reuse by using the efficient blocking algorithm for directional antennas. In this paper, we propose the PCDUDMAC (Power Controlled DUDMAC) protocols. In the PCDUDMAC protocol, the power control of DATA/DACK in data channel saves transmission power and improves spatial reuse. We confirm the throughput performance of the proposed MAC protocol by computer simulations using Qualnet ver.3.8 simulator.

• Journal of Korea Multimedia Society
• /
• v.10 no.9
• /
• pp.1165-1174
• /
• 2007

Mobile ad hoc networks suffer from the re-construction of the routing path as a node on the path moves away and/or fails. In this paper we propose a multipath routing scheme, designed for the network based on the directional antennas, in which a new path is quickly recovered by do-touring to an alternative neighbor called braid. Simulations are conducted in random networks with 50 nodes uniformly deployed in a $1,000m{\times}1,000M$ area where, all nodes have a transmission range of 250m and the average node moving speed varies from 0 to 10m/s. The proposed approach under the ideal antenna with K(>1) directional sectors achieves better results compared with the case of K=1, the omnidirectional antenna model, in terms of the metrics: packet delivery ratio and average number of hops for the routing paths. As further study, a scheme to alleviate the heavy amount of latency accompanied by the rout setup is urgently required.

• Proceedings of the Korea Contents Association Conference
• /
• 2004.11a
• /
• pp.296-301
• /
• 2004

The Wireless Sensor Network is technology that makes possible utilize the information collected from rescue, the agricultural and livestock management system, and the home automation system by using an ultra-small sized, ultra-lightweight sensor module. This study proposes the routing protocol with directional nature that can improve the utilization by higher energy efficiency and reliability than those of existing studies on data transmission, and we also analyze the current studies, make a comparison of them in performance.

• Proceedings of the Technology Innovation Conference
• /
• 2002.06a
• /
• pp.181-200
• /
• 2002

최근 급진전되고 있는 인터넷의 광대역화와 다양한 멀티미디어 컨텐츠의 수요확대 그리고 인터넷 이용자의 급증 등으로 인터넷 트래픽은 기하급수적으로 증가하고 있다. 그러나 최선형 패킷교환방식인 현 인터넷은 급증하는 네트워크 수요를 감당하기에 이미 기술적 한계를 드러내고 있을 뿐 아니라, 네트워크 확장을 통하여 급증하는 트래픽을 수용하는 것도 경제적으로 한계수위에 도달하고 있다. 따라서 네트워크 수요 대비 공급량의 불균형으로 인터넷망에서의 혼잡(congestion)문제가 점차 중요한 이슈로 제기되고 있으며, 이런 문제의 해결방안으로 네트워크공급을 늘리거나, 초과수요를 줄이는 방안에 대한 논의와 구체적인 노력이 이루어지고 있다. 이에 본 고에서는 간단한 기술 경제학적 모형을 이용하여 혼잡의 원인과 이에 대한 해결방향에 대하여 분석적인 설명을 시도하였다. 특히 본 고에서는 인터넷 혼잡의 원인이 '부정적 네트워크 외부성' 이 존재하기 때문이며, 실무적으로 혼잡문제 해결의 대표적인 대안으로 적용되고 있는 네트워크의 용량확대는 혼잡해결의 근본적인 대안이 되지 못하고, 반면 실무적으로 별로 주목받고 있지 않는 네트워크 투자를 최소화하고 트래픽을 통제할 수 있는 '혼잡세'를 부과할 수 있는 요금제 도입이 효율적인 혼잡 해결방안 임을 밝히고 있다.