• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.383-385
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• 2007

IEEE 802.15.4 is a standard designed for low rate wireless personal area networks(LR-WPANs). This paper presents the analytical model for to derive the saturation throughput of collision avoidance protocol of IEEE 802.15.4 in ad hoc network. we assume that nodes placed according to a two-dimensional Poisson distribution.

• 한국안전학회지
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• 제32권1호
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• pp.140-144
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• 2017

Fire protection for nuclear power plants should be designed according to the concept of "Defense in Depth" to achieve the reactor safety shutdown. This concept focuses on fire prevention, fire suppression and safe shutdown. Fire prevention is the first line of "Defense in Depth" and the licensee should establish administrative measures to minimize the potential for fire to occur. Administrative measures should include procedures to control handling and use of combustibles. Electrical cables is the major contributor of fire loads in nuclear power plants, therefore electrical cables should be fire retardant. Electrical cables installed in nuclear power plants should pass the flame test in IEEE-383 standard in accordance with NUREG-0800, "Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants". To assure the fire retardant of electrical cables during design life, both aged and unaged cable specimens should be tested in accordance with IEEE-383. It can be generally thought that the flammability of electrical cables has been increased by wearing as time passed, however the results from fire retardant tests performed in U.S.A and Korea indicate the inconsistent tendency of aging and consequential decrease in flammability. In this study, it is expected that the effective methodology for validation of fire retardant performance would be identified through the review of the results from fire retardant tests.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
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• pp.381-383
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• 2002

This paper proposes a MATLAB program for solving security-constrained optimal power flow using linear programming. Security-constrained optimal power flow can find an optimal generation satisfying bus voltage limits, line flow limits, reactive generation limits, even if contingency occurs. Sensitivity matrixes are obtained based on power flow solutions with and without single line contingency. This program is tested for an IEEE 14bus system with 5 generators Results shows good ability of finding optimal solution in case of a single line contingency.

• 한국안전학회지
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• 제31권2호
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• pp.1-9
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• 2016

The standard procedure of fire modeling was reviewed to minimize the user dependence, based on the NUREG-1934 and 1824 reports. The hazard analysis of lubricating oil fires in the air compressor room of domestic nuclear power plant (NPP) was also performed using a representative fire model, FDS (Fire Dynamics Simulator). The area ($A_f$) and location of fire source were considered as major parameters for the realistic fire scenarios. As a result, the maximum probability to exceed the thermal damage criteria of IEEE-383 unqualified electrical cables was predicted as approximately 70% with $A_f=1m^2$. It was also found that for qualified electrical cables, the maximum probabilities of exceeding the criteria were 2% and 90% with $A_f=2$ and $4m^2$, respectively. It was concluded that all electrical cables should be replaced with IEEE-383 qualified cables and the dike to restrict as $A_f{\leq}2m^2$ should be installed at the same time, in order to assure the thermal stability of electrical cables for lubricating oil fires in the air compressor room of domestic NPP.

• 한국정보과학회논문지:정보통신
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• 제35권5호
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• pp.374-383
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• 2008

무선랜(Wireless LAN)으로 현재 널리 쓰이고 있는 IEEE 802.11 표준 프로토콜은 채널상태에 따라 다양한 데이타 전송률(data rate)을 지원한다. 서로 다른 데이타 전송률을 사용하는 여러 단말들이 동일한 무선랜에 존재할 경우 낮은 전송률을 사용하는 단말 때문에 높은 전송률을 지원하는 단말의 처리율이 저하되는 성능 이상(Performance Anomaly) 문제가 발생한다. 이러한 성능 이상 문제를 해결하는 방법으로 모든 단말에 동일한 전송시간을 제공하는 시간 공정성(Temporal Fairness) 개념이 제안되었다. 그러나 현재 제안된 대부분의 시간 공정성 제공방안은 MAC 계층에서 보낼 패킷이 항상 있는 상황을 가정하여 전송계층 프로토콜의 특성은 고려하지 않았다는 제약점을 가지고 있다. 본 논문에서는 대표적인 전송계층 프로토콜인 TCP와 UDP가 사용되는 환경에서 현재까지 제시된 시간 공정성 제공방안이 어떤 성능을 보이는지 분석하고, 전송계층의 특성 때문에 발생하는 문제점들을 해결하기 위해서 AP에 높은 우선 순위를 제공하는 AP 우선순위 방법과 노드의 CWmin 을 조절하는 동적 CWmin 조절 방안을 제안한다. 제안한 방법을 적용하면 다중 데이타 전송률을 사용하는 무선랜에서 전송계층으로 TCP, UDP 프로토콜이 혼재할 경우에도 전체적인 시간 공정성을 유지할 수 있고 전체 데이타 처리율(total throughput)이 향상된다는 것을 컴퓨터 시뮬레이션을 이용하여 검증하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.379-383
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• 1997

This paper focuses on self-organization of fuzzy rules for performance management of computer communication networks serving manufacturingsystems. The performance managment aims to improve the network performance in handling various types of messages by on-line adjustment of protocol parameters. The principle of fuzzy logic has been used in repressenting the knowledge of human expert on the performance management and in deriving manafement decisions. In this paper, we present an of this self-organization is domonstrated by discrete simulation of an IEEE 802.4 network.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.383-386
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• 2000

Fuse mounted elbow connector used for pad mounted transformer was designed and investigated. Requirements of electrical ratings such as partial discharge, ac withstand voltage and impulse voltage and material properties were proposed in accordance with IEEE 386 and pre-standard (PS) 147-219∼229 of KEPCO. The connector can be jointed with pad mounted transformer and current limiting fuse which is installed inside of the connector easily replaced with new one in the case of breakdown of the fuse. Electric field analysis was also introduced in other to verify the reliability of the design.

• 한국안전학회지
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• 제28권3호
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• pp.39-43
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• 2013

The present study has been conducted to investigate the fire combustion properties and fire behavior of an IEEE-383 qualified flame retardant cable. The reference reaction rate and reference temperature which are commonly used in pyrolysis model of fire propagation process was obtained by the thermo-gravimetric analysis of the cable component materials. The mass fraction of FR-PVC sheath abruptly decreased near temperature range of $250{\sim}260^{\circ}C$ and its maximum reaction rate was about $2.58{\times}10^{-3}$[1/s]. For the XLPE insulation of the cable, the temperature causing maximum mass fraction change was ranged about $380{\sim}390^{\circ}C$ and it has reached to the maximum reaction rate of $5.10{\times}10^{-3}$[1/s]. The flame retardant cable was burned by a pilot flame meker buner and the burning behavior of the cable was observed during the fire test. Heat release rate of the flame retardant cable was measured by a laboratory scale oxygen consumption calorimeter and the mass loss rate of the cable was calculated by the measured cable mass during the burning test. The representative value of the effective heat of combustion was evaluated by the total released energy integrated by the measured heat release rate and burned mass. This study can contribute to study the electric cable fire and provide the pyrolysis properties for the computational modeling.