• 한국심리학회지 : 문화 및 사회문제
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• 제21권3호
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• pp.419-455
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• 2015

연구 1에서는 특정영역 위험감수 척도(Domain-Specific Risk Taking Scale)를 번안한 후, 대학생 438명에게 설문지를 실시하여 6요인 구조와 적절한 수준의 신뢰도와 타당도를 확인하였다. 연구 2에서는 연구 1과 다른 표집의 대학생 497명의 자료로 두 가지 연구문제를 탐구하였다. 첫째, NPI(Narcissistic Personality Inventory)와 PNI(Pathological Narcissism Inventory)로 측정한 자기애와 위험감수의 관계를 감각추구와 이득-위험지각이 매개하는지 알아보았다. 경로분석과 매개효과 검증결과 NPI자기애는 감각추구와 이득지각의 완전매개, PNI자기애는 감각추구와 이득지각의 부분매개를 통해 위험감수에 영향을 미치는 것으로 나타났다. 둘째, 이득-위험지각과 위험감수의 관계에서 조건부 자아가치감이 조절하는지 알아보았다. 다집단분석 결과 이득-위험지각이 위험감수 전체점수로 가는 경로에서 도덕성 조건부 자아가치감이 조절하는 것으로 나타났고, 위험감수의 6개 하위영역으로 가는 경로들에서는 조절효과를 보인 조건부 자아가치감의 하위유형들이 다양하게 나타났다. 이러한 결과를 이전의 위험감수연구와 비교하고 자기애 유형과의 관련성을 논의하였다.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.18-29
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• 2015

State Estimation (SE) is the basis of a variety of advanced applications used in most modern power systems. An SE problem formed with enough phasor measurement units (PMUs) data is simply a linear weighted least squares problem requiring no iterations. Thus, designing a minimum-cost placement of PMUs that guarantees observability of a power system becomes a worthy challenge. This paper proposes an equivalent integer linear programming method for substation-oriented optimal PMU placement (SOOPP). The proposed method uses an exhaustive search to determine a globally optimal solution representing the best PMU placement for that particular power system. To obtain a more comprehensive model, contingencies and the limitation of the number of PMU measurement channels are considered and embodied in the model as changes to the original constraints and as additional constraints. The proposed method is examined for applicability using the IEEE 14-bus, 118-bus and 300-bus test systems. The comparison between SOOPP results and results obtained by other methods reveals the excellence of SOOPP. Furthermore, practical large-scale power systems are also successfully analyzed using SOOPP.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.541-548
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• 2017

An increasing concern is paid to short-term voltage stability with the growth of penetration of induction motor loads. Reactive power reserve(RPR) of power system is critical to improve voltage stability. A definition of short-term voltage stability-related RPR(SVRPR) is proposed. Generators vary their contributions to voltage stability with their location and system condition, etc. Voltage support coefficient based on the second-order trace sensitivity method is proposed to evaluate SVRPR's contribution to short-term voltage stability. The evaluation method can account for the generator's reactive support in transient process and the contingency severity. Then an optimization model to improve short-term voltage stability is built. To deal with multiple contingencies, contingency weight taking into account both its probability and severity is proposed. The optimization problem is solved by primal dual interior point method. Testing on IEEE_39 bus system, it is indicated that the method proposed is effective. Short-term voltage stability is improved significantly by the way of SVRPR optimization. Hence, the approach can be used to prevent the happening of voltage collapse during system's contingency.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2002년도 학술대회 논문집
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• pp.285-290
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• 2002

Power systems are becoming larger and larger for meeting electric power demand. Therefore, the over-currents resulting from contingencies such short circuits are increasing higher. The Maximum short circuit current of modern power system is becoming so large that circuit breaker are not expected th be able to shut down the current in the future. In order to cut over-currents, a system composed of a superconducting fault current limiter(SFCL) and traditional breaker seems to provide a promising solution for future power operation. In present paper, three line-to-ground fault is assumed to happen at the center of 345kV transmission lines in a large capacity electric power system The superconducting fault current limiter was represented using a commutation type, which consists of a non-inductive superconducting coil and current limiting element(resistor or reactor). The introduction merits of the SFCL were investigated quantitatively by RTDS/EMTDC from the viewpoint of current limiting performance, the prevention of the voltage drop at the load bus and comparison characteristics for two type SFCL. Desired design specification and operation parameters of SFCL were also given qualitatively by the performance evaluation of the two type SFCL in the power system.

• Journal of Electrical Engineering and Technology
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• 제6권4호
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• pp.484-492
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• 2011

Power system analyses, which involve the handling of massive data volumes, necessitate the use of effective visualization methods to facilitate analysis and assist the user in obtaining a clear understanding of the present state of the system. This paper introduces an interface that compensates for the limitations of the visualization modules of dynamic security assessment tools, such as PSS/e and TSAT, for power system variables including generator rotor angle and frequency. The compensation is made possible through the automatic provision of dynamic simulation data in visualized and tabular form for better data intuition, thereby considerably reducing the redundant manual operation and time required for data analysis. The interface also determines whether the generators are stable through a generator instability algorithm that scans simulation data and checks for an increase in swing or divergence. The proposed visualization methods are applied to the dynamic simulation results for contingencies in the Korean Electric Power Corporation system, and have been tested by power system researchers to verify the effectiveness of the data visualization interface.

• 한국멀티미디어학회논문지
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• 제5권3호
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• pp.323-330
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• 2002

최근의 내장형(embedded) 실시간 운영체제들은 응용 분야에 따라 다양하게 개발되고 있다. 이러한 운영체제들의 중요한 차이점은 시간적인 제한 사항을 제어할 수 있는 타스크 스케줄링 기능과 다양한 환경에서 사용할 수 있는 장치들의 개발에 있다. 본 연구에서는 우선순위 기반의 선점(preemption) 메커니즘을 지원하는 $\mu$C/OS-II버전 2.03에서 동일 우선 순위를 가진 다중 태스크들을 관리하기 위한 시분할 방식의 Round/Robin(R/R) 타스크 스케줄링 기능을 추가하였다. 이를 위해 본 연구에서는 $\mu$C/OS-II의 커널 구조에서 가장 중요한 이베트 대기 리스트 구조를 제안하고, 제안된 구조에 대해 동일 우선순위를 가지는 다중 타스크의 실행 결과를 제시한다.

• 전기학회논문지P
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• 제65권4호
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• pp.255-261
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• 2016

Korean Power System are operating a load shedding system to prevent voltage instability phenomenon caused by severe line contingencies. In order to apply the load shedding scheme should be selected a location, amount, delay time. Current load shedding system is load shedding amount that has been calculated in the steady-state analysis to load shed the total amount in first level, load shedding amount calculated in advance, it is possible to perform an unnecessary load shedding. In this paper, set a multi-level load shedding control strategy step-by-step selection of load shedding amount for the prevention of excessive load shedding. In addition, through a voltage resilience analysis of the power system by applying motor load ratio and sensitivity parameter to selection the multi level load shedding ratio and delay time. For this reason, to take advantage of the limit data of interchange power, by utilizing interface power flow data to set a multi-level load shedding control strategy for the stabilization of the Korean Power System.

• Journal of Electrical Engineering and Technology
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• 제12권5호
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• pp.1689-1696
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• 2017

In recent academic and industrial circles of the Republic of Korea, the securement of available reactive power reserve against the line faults is at issue. Thus, simulations have been performed for the securing of effective reactive power reserve (effective Q) to prepare for the line faults and improve reactive power monitoring and control methods. That is, a research has been conducted for the fast-decoupled Newton-Raphson method. In this study, a method that distinguishes source and sink regions to carry out faster provision of information in the event of line fault has been proposed. This method can perform quantification with the formula that calculates voltage variations in the line flow. The line flow and voltage changes can be easily induced by the power flow calculation performed every second in the operation system. It is expected that the proposed method will be able to contribute to securement of power system stability by securing efficient reactive power. Also, the proposed method will be able to contribute to prepare against contingencies effectively. It is not easy to prepare quickly for the situation where voltage drops rapidly due to the exhaustion of reactive power source by observing voltage information only. This paper's simulation was performed on the large scale Korean power system in steady state.

• 한국산업융합학회 논문집
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• 제23권3호
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• pp.393-401
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• 2020

According to the research and investigations performed on Port Facilities for cargo-works of hazardous materials around the Port of Busan, a conclusion was drawn that the manually operating foam tower monitors are ineffective as they are hard to access due to the radiant heat under contingency circumstances such as a fire. Moreover, in some cases, the effective range of Foam Tower Monitors are insufficient to reach docked ships and manifolds where hazardous materials are being unloaded. In addition, Dangerous Goods freights are inadequately and inefficiently stored regardless properties of hazardous substances due to complicated local regulations, and some are equipped with inapplicable facilities for docked ships. Therefore, in order to effectively counteract the contingencies and obtain safety, it would be recommended to install adequate facilities.

• 한국도서관정보학회지
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• 제33권4호
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• pp.1-18
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• 2002

정보이용과 이용자 문제에 대한 문헌정보학의 관심은 전통적으로 현재적 이용자들의 공식적 채널을 통한 정보의 추구와 이용에 집중되어 있었다. 그 결과 지식, 정보의 흐름에서 소외된 계층에 대한 연구는 미비한 실정이다. 이 글은 관련 논의에서 중요하게 다루어지지 않았던 사회적 소외계층의 정보요구에 대한 인식의 폭을 확대해야 한다는 점을 지적한다. 이를 위하여 적절한 방법론을 모색하기 위한 논의의 토대를 제공하고, 특히 사회, 경제적 소외계층에 대한 조사에 많이 적용되는 문화 기술 법을 사용하여 정보소외와 정보 빈곤의 문제에 접근할 수 있는 가능성을 가늠하고자 하였다.