• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.51-54
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• 1991

As a transmission network planning should be optimal in the sense of technology, economy and reliability, an adequate optimization tool is required. The simulation model is valuable at this case. It enables the planner to detect the weak points of the system by providing the planner with unsupplied powers, operating cost, and active losses at each substation node and each line. This paper represent the example of application of simulation model for power system planning.

• Journal of Plant Biology
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• v.31 no.4
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• pp.289-298
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• 1988

The pattern of elongation in the developing hypocotyl of Glycine max shows that the elongation generally proceeds from base to the cotyledonary node in acropetal diredtion, although earlier elongation takes place through the entire hypocotyl. Because the differentiation of the vascular cambium in the hypocotyl advances also acropetally, it can be seen that the acropetal wave of hypocotyl elongation is associated with the acropetal differentiation of the cambium in the hypocotyl elongation is associated with the acropetal differentiation of the cambium in the hypocotyl elongation is associated with the acropetal differentiation of the cambium in the hypocotyl. The elongation of procambial cells occurs not only during active elongation but also after cessation of elongation of the hypocotyl. In tangential view, the procambium of the hypocotyl in early stage has homogeneous structure composed of short cells. Subsequently, these procambial cells elongate actively and then become elongated long cells. These long cells eventually become fusiform initials, while some of elongated long cells are transversely divided and then converted into ray initials. The characteristics of the vascular cambium are entirely acquired some time after hypocotyl elongation is completed, and the transitin from procambium to vascular cambium in the hypocotyl is a rather gradual process.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.781-784
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• 1998

An image segmentation approach based on the fuzzy worm searching and MIN-MAx clusterng algorithm is proposed in this paper. This algorithm deals with fuzzy worm value and min-max node at a gross scene level, which investigates the edge information including fuzzy worm action. But current segmentation methods based edge extraction methods generally need the mask information for the algebraic model, and take long run times at mask operation, wheras the proposed algorithm has single operation ccording to active searching of fuzzy worms. In addition, we also genetic min-max clustering using genetic algorithm to complete clustering and fuzyz searching on grey-histogram of image for the optimum solution, which can automatically determine the size of rnages and has both strong robust and speedy calculation. The simulation results showed that the proposed algorithm adaptively divided the quantized images in histogram region and performed single searching methods, significantly alleviating the increase of the computational load and the memory requirements.

• Transactions on Electrical and Electronic Materials
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• v.18 no.5
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• pp.303-309
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• 2017

The flexible AC transmission system (FACTS) provides a new advanced technology solution to improve the flexibility, controllability, and stability of a power system. The unified power flow controller (UPFC) is outstanding for regulating power flow in the FACTS; it can control the real power, reactive power, and node voltage of distribution networks. This paper investigates the performance of the UPFC for power flow control with a series of step changes in rapid succession in a power system steady state and the response of the UPFC to distribution network faults and islanding mode. Simulation was carried out using the MATLAB's simulink sim power systems toolbox. The results, which were carried out on a 5-bus test system and a 4-bus multi-machine electric power system, show clearly the effectiveness and viability of UPFC in rapid response and independent control of the real and reactive power flows and oscillation damping [6].

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11b
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• pp.1229-1232
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• 2003

Ad Hoc 네트워크에서 on demand 라우팅 프로토콜로 대표적인 AODV(Ad Hoc On Demand Distance Vector Routing)는 table driven 기반의 라우팅 프로토콜과 비교해 active route만을 라우팅 테이블에 저장하기 때문에 오버헤드가 작고 경로단절시 경로복구를 통해 경로 재설정할 수 있는 장점을 가지고 있으나 경로복구시 대역폭 낭비가 심하고 복구시간이 길다는 drawback을 가지고 있다. 이러한 단점은 많은 라우팅 패킷의 발생으로 기인하는 점이 있다. 본 논문에서는 Expanding Ring Search 알고리즘에서 time out은 timestamp를 이용하여 네트워크 상황에 맞게 가변적으로 적용하는 알고리즘을 개선하여 hop 수에 따라 node traversal time을 설정하도록 제안하였다. 제안한 알고리즘은 시뮬레이션을 통하여 검증하였으며 라우팅 패킷의 발생을 줄이고 throughput에서 향상을 보였다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.391-394
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• 2006

무선 센서 네트워크에서 각 센서 노드는 에너지의 한계를 가지기 때문에, 에너지 소비문제는 매우 중요한 이슈이다. 조밀한 환경의 센서 네트워크에서 모든 노드들이 센싱에 참여한다면, 센싱영역의 중복영역이 커지게 되고, 이로 인해 불필요한 에너지를 소비하게 된다. 본 논문에서는 connectivity 와 coverage 를 보장할 수 있고, 효율적으로 활성화 노드를 선택할 수 있는 기법을 제안하여, 불필요한 센서 노드들의 에너지소비를 막아 전체적인 네트워크의 lifetime 을 연장시키고자 한다.

• Journal of Communications and Networks
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• v.17 no.5
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• pp.482-490
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• 2015

This article exploits spatial diversity for jamming to prevent wiretapping in the extreme case in which an eavesdropper is located near the source and a common jamming signal is unavailable. To address this challenge, the jamming signal is allowed to carry a random binary message. Then, it is proposed that the active intermediate node transmits this jamming signal and the decoding of this signal at both source and destination is physically secured as result of using the physical-layer security method. If the source and the destination securely and correctly decode this jamming message, the source transmits another message which is created from combining its information message and the decoded message using the network-coding method. Therefore, this method prevents the transmissions from being eavesdropped upon by the source-wiretapping.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.189-191
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• 2000

기존 네트워크의 정적인 구조와 그에 대한 사용자들의 요구가 충족되지 못하고, 시간이 지남에 따라 점점 늘어만 가는 네트워크 관리대상의 숫자는 액티브 네트워크와 Script MIB의 등장을 가져왔다. 사용자들이 직접 네트워크 서비스를 구성하고 설치, 이용할 수 있는 액티브 네트워크에 기존의 SNMP agent가 동적으로 생성된 관리정보를 관리자에게 돌려줄 수 있는 Script MIB를 결합하여, 액티브 네트워크가 가지고 있는 다중 수행환경을 관리하는 방법과 Script MIB를 보완하는 방법을 제시한다. 또한 결합에 사용되는 메시지의 구조와 전체적인 동작 과정을 예시함으로써, 이러한 결합 방법이 갖는 효율성을 나타낸다.

• Journal of the Korea Society for Simulation
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• v.13 no.4
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• pp.55-69
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• 2004

In MANET(Mobile Ad-hoc Network), unlike in wired networks, a path configuration should be in advance of data transmission along a routing path. Frequent movement of mobile nodes, however, makes it difficult to maintain the configured path and requires re-configuration of the path very often. It may also leads to serious problems such as deterioration of QoS in mobile ad-hoc networks. In this paper, we proposed a Reactive Routing Keyword (RRK) routing procedure to solve those problems. Firstly, we noticed it is possible in RRK routing to assign multiple routing paths to the destination node. We applied this feature into active networks and SNMP information based routing by storing unique keywords in cache of mobile nodes corresponding to present and candidate routings in a path configuration procedure. It was shown that the deterioration of QoS which may observed in Dynamic Source Routing(DSR) protocol was greatly mitigated by using the proposed routing technique.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.157-158
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• 2006

무선 센서 네트워크에서 각 센서 노드는 에너지의 한계를 가지기 때문에, 에너지 소비문제는 매우 중요한 이슈이다. 조밀한 환경의 센서 네트워크에서 모든 노드들이 센싱에 참여한다면, 센싱영역의 중복영역이 커지게 되고, 이로 인해 불필요한 에너지를 소비하게 된다. 본 논문에서는 WSN 에서 connectivity 와 coverage 를 보장할 수 있는 효율적인 활성화 노드를 선택하는 기법을 제안하여, 불필요한 센서노드들의 에너지소비를 막고 전체적인 네트워크의 lifetime 을 연장시키고자 한다