• 전기학회논문지
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• 제56권11호
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• pp.2010-2016
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• 2007

PID control is windely used to control stable processes, However, its application to integrating processes is less common. In this paper, we proposed a stable PID controller tuning method for integrating processes with time delay using model reduction method. For proposed model reduction method, it disconnect an integrating factor from integrating processes and reduces separate process using reduction method. and it connect an integrating factor to reduced model. We can obtain stable integrating processes using P controller in inner feedback loop and PID tuning is then used to cancel the pole of the feedback loop. This guarantees both robustness and performance. Simulation examples are given to show the good performance of the proposed tuning method comparing with other methods.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권4호
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• pp.234-234
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• 2004

Measuring ground resistance has been a popular method of evaluation of the grounding electrode performance. If some portions of grounding electrodes are lost by corrosion, aging or other reasons, consequent deteriotation of the grounding performance would be resulted. It is one of the reasons why it is required to evaluate the performance of grounding systems regularly. However, in case of the electric facilities with multi-grounded system such as power substations with multi-grounded overhead ground wires and/or distribution line neutrals, it is practically difficult to disconnect neutrals or skywires from the substation grounding mesh for the ground resistance measurement. In this paper, a method for the grounding performance measurement of multi-grounded systems, which is based on the measuring ground current distributions, has been proposed. A field test results has shown the validity of the proposed test method.

• 경영과정보연구
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• 제25권
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• pp.35-55
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• 2008

We draw on well-established thinking in the complementary fields of organization theory and strategic management to develop a model explaining why fit among a firm's competitive strategy, its structure, and its technology is a prerequisite for superior performance. The contributions of this theoretical treatise are twofold. Firstly, it helps reduce the disconnect in thinking that exists between the strategy and organization-theory literatures on business-level issues. Secondly, it reveals the importance of managing the coalignment among strategy, structure, and technology which, in turn, forces recognition that competitive advantage does not exist in a static state but in a dynamic condition.

• 대한전기학회논문지:전력기술부문A
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• 제52권4호
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• pp.201-206
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• 2003

Power system is analyzed by three methods of load flow, fault calculation, and voltage stability. Among there, load flow is calculated to flow of power in power in system at steady state. But, load flow is difficult to analyze to flow of power in substation, because power flow frequently alter by various equipments such as circuit bleaker, disconnect switch and shunt reactor. Particular, in 765[㎸] system, because of form of 1.5GB for stable operation, structure of substation has been very complex. In this paper, we describe technique for application of load flow algorithm in simulator for 765[㎸] substation. For this technique, we built each database for various equipments and considered form of 1.5GB Data as form of bus and line, for application of load flow, are acquired from built database, and then calculate load flow in substation. And. results of load flow are outputted in screen of operator console program.

• 전력전자학회논문지
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• 제10권4호
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• pp.403-410
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• 2005

본 논문은 정지궤도 위성을 위한 완전조절방식을 갖는 태양전지 어레이 션트 전압조절기를 나타낸다. 스위칭 션트 전압조절기는 태양전지 어레이 전력을 조절하는 어레이 스위치 모듈들로 구성된다. 이러한 태양전지 어레이 션트 모듈들은 스위칭을 통해 버스에 태양전지 회로가 접속되거나 분리되며, 단지 FPGA 로직변경 만을 통해 이전의 회로설계로부터 간단하게 확장이 가능하다. 제안된 설계회로를 검증하기위해 제어로직 및 최악조건해석이 수행되었으며, 시뮬레이션 및 실험결과를 보여준다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.134-135
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• 2012

This paper analyzes the characteristics of the power system of Jeju island in 2014, which has wind farms with the support of BESSs (Battery Energy Storage Systems). In the simulation, the electrical loads are predicted based on Korea Power Exchange's data and the wind turbines are considered with new installed plans within 2014. The situation that some wind farms are forced to disconnect from the grid instantaneously is considered. The BESSs are controlled by using SOC (State of Charge) and power smoothing control algorithm. The simulation results show the effectiveness of the proposed method.

• 한국화재조사학회지
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• 제8권1호
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• pp.41-48
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• 2006

The purpose of this study is to identify the fire danger of the electric radiant heating system and check the way how to use it and the problems that could be possible through a actual case. We carry out an experiment to identify the possibility of the fire in the similar condition of the actual fire case. The results of this study are as follows. It is a possible condition to fire if the air blast of the electric radiant heating system is blocked by some combustible materials such as plastic bags continuously. A temperature sensor and a residual current device are necessary to disconnect the power source. It is also necessary to attach a notice in front of the electric radiant hearing system that shows users the fire danger to forbid the possible fire. Fires could be happened by internal defects of the electronic products. However, we can also find many external reasons to happen fires. Therefore, we need to check all reasons to make fires in the scene of a fire.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2004년도 봄 학술발표논문집 Vol.31 No.1 (B)
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• pp.55-57
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• 2004

이동 컴퓨팅(Mo띠le Computing) 환경에서 빈번한 접속 단절은 클라이언트의 캐시 일관성(Consistency) 문제로 직결된다. 본 논문에서는 이를 해결하기 일한 무효화 보고(Invalidation Report. In)중 하나를 제시한다. 기존의 IR방식은 대량의 데이터와 빈번한 데이터의 갱신(Update)시 IR 길이의 증기폭이 상당히 크다. 이는 타임스탬프가 IR에서 차지하는 비중이 큼으로써 오는 현상이다. 또한 기존방식은 캐시 레벨의 선택적 청취(Selective tuning)를 지원하지 못하는 문제점을 가지오 있다. 이러한 점을 극복하고자 B＋Tree를 기반으로 시간 값을 구성하고 이에 따른 데이터 아이디를 재구성하는 IR방식을 제안한다. 이를 활용하면 각 클라이언트가 자신의 단절(Disconnect)된 시간에 맞는 갱신 정보를 확인할 수 있게 된다. 이러한 방법은 기존 IR의 단점을 보완하며 선택적 청취론 유도할 수 있는 효과적인 방법이다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2018년도 춘계학술발표대회
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• pp.581-583
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• 2018

사물인터넷 (IoT) 기술의 발전으로 최근 많은 가전제품 및 전자 제품들이 IoT 기술과 결합되어 출시되고 있으며, 전원을 연결하는데 사용되는 멀티탭 또한 IoT 기술이 접목된 제품이 나오고 있다. IoT 멀티탭은 전원 on/off 를 원격으로 제어 할 수 있어서 사용자 편의성을 더욱 높여주었다. 그러나, 현재 출시된 IoT 멀티탭 제품들은 각 구별 제어가 불가능하고 대기전력 차단 기능이 미흡하여 절전 기능이 빈약하다. 따라서 본 논문에서는 멀티탭의 각 구를 개별 조작할 수 있고, 대기전력을 측정 및 차단 기능을 제공함으로써 전력 낭비를 줄일 수 있는 IoT 멀티탭을 제안한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권4호
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• pp.1266-1285
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• 2022

Compact E-cash is the first scheme which can withdraw 2^l coins within 𝒪(1) operations and then store them in 𝒪(𝑙) bits. Because of its high efficiency, a lot of research has been carried out on its basis, but no previous research pay attention to the privacy of payees and in some cases, payees have the same privacy requirement as payers. We propose a double-blind compact E-cash scheme, which means that both the payer and the payee can keep anonymous while spending. In our scheme, the payer and the bank cannot determine whether the payees of two different transactions are the same one and connect the payee with transactions related to him, in this way, the privacy of the payee is protected. And our protocols disconnect the received coin from previous transaction, then, the coin can be transferred into an unspent coin which belongs to the payee. The proposed e-cash scheme is secure within y-DDHI and LRSW assumption.