• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.411-416
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• 1991

Operation simulation is a key factor to evaluate investment and operation in a power utility. Probabilistic production simulation is of major concern. With pumped-storage plant, production simulation is not an easy task, because its economy should fully be exploited. In addition, usual operation interval is a week rather than a day. Most existing models are based on approximate production simulation such as adopting simple priority orders of generations. This study is based on the more elaborate model developed by authors. Further, a policy of weekly coordination is established based on the Maximum Principle. Chronological load curve instead of usual load duration curve is used and the accuracy in simulation is enhahced. Resulting economics are compared. Deviation between these two toad curve is shown.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.58-60
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• 2005

STATCOM whose performance is higher than SVC at a view point of a continuous controllability of reactive power and response time is reviewed in this paper. Also, basic principle of STATCOM operation and the functions of each component are explained. 30kVA STATCOM system is practically designed according to design procedure in reference [2, [7] to develop a cost-effective and compact compensator. Its operation characteristics are verified by the simulation.

• 조명전기설비학회논문지
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• 제25권8호
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• pp.20-29
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• 2011

This paper presents an improved phase-shift pulse-width modulation (PWM) full-bridge converter using a blocking capacitor. As the proposed converter reduces the circulation energy by inserting only one series blocking capacitor at the primary side of the conventional phase-shift PWM full-bridge converter structure, it improves the operation characteristics of the conventional converter. In this paper, first, the operation of conventional phase-shift PWM full-bridge converter is roughly reviewed, and then the operational principle of the proposed converter is classified and explained by each mode. After that, a prototype design example based on the operational principle is shown. Then, the improved operation characteristics of the proposed converter are actually verified through the experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.489-491
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• 1993

Many optimization problem or multiple attribute, multiple alternative decision making problem may have fuzzy evaluation factors. In this case, fuzzy number operation technique is needed to evaluate and compare object functions which become fuzzy sets. Generally, fuzzy number operations can be defined by extension principle of fuzzy set theory, but it is tedious to do fuzzy number operations by using extension principle when the membership functions are defined by complex functions. Many fast methods which approximate the membership functions such as triangle, trapezoidal, or L-R type functions are proposed. In this paper, a fast fuzzy number operation method is proposed which do not simplify the membership functions of fuzzy numbers.

• 시큐리티연구
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• 제16호
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• pp.161-187
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• 2008

본 연구는 세계적으로 확산되고 있는 테러리즘과 관련하여 경호임무 수행시 나타난 위해사례분석을 통하여 도출된 문제점들을 다각도에서 분석하여 현재 한국 경호제도의 발전방안을 제시하고자 하였다. 본 연구를 수행하기 위해 현재 한국의 경호관계법, 경호의 원칙과 방법론, 테러와 뉴테러리즘에 대한 기본 이론을 고찰하였다. 그리고 경호위해 사례 중 박근혜 위해사례를 중점적으로 분석한 질적사례연구로 연구를 수행하였다. 본 연구를 통한 한국 경호제도의 발전방안은 다음과 같다. 첫째, 법제도적인 측면에서는 테러방지법과 요인경호법 제정을 재검토해야 할 것이다. 그리고 민간경호의 근거법인 경비업법의 개정을 통해 민간경호의 발전을 도모해야 한다. 둘째, 민간경호 육성의 측면에서 세분화되지 않고 있는 교육훈련 프로그램을 정비 해야하고 강화해야 한다. 또 경비업법에 의한 신변보호업무를 활성화하고 시장을 확대해야 한다. 이러한 관점에서 민간경호원에 대한 국가자격증을 도입해야하고, 공경호의 대표적인 대통령실 경호처에서는 선진기술들을 민간경호로 이전해야할 것이다. 셋째, 운영적 측면에서는 SCE원칙, 인적방벽효과의 원리, 촉수거리확보의 원칙, 체위확장의 원칙, 일직선의 원칙, 대피우선의 원칙 등 경호원칙에 입각한 경호운영이 요구되는 바, 이러한 운영을 위해 선행적으로 예방경호의 중요성이 강조되며 철저한 경호경비기획이 이루어져야 할 것이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.129-131
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• 2006

This paper presents a new ZVS-PWM high frequency inverter. The ZVS operation is achieved in the whole load range by using a simple auxiliary reverse blocking switch in parallel with series resonant capacitor. The operating principle and the operating characteristics of the new high frequency circuit treated here are illustrated and evaluated on the basis of simulation results. It was examined that the complete soft switching operation can be achieved even for low power setting ranges by introducing the high frequency dual duty cycle control scheme. In the proposed high frequency inverter treated here, the dual mode pulse modulation control strategy of the asymmetrical PWM in the higher power setting ranges and the lower power setting ones, the output power of this high frequency inverter could introduce in order to extend soft switching operation ranges. Dual duty cycle is used to provide a wide range of output power regulation that is important in many high frequency inverter applications. It is more suitable for induction heating applications the operation and control principle of the proposed high frequency inverter are described and verified through simulated results.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.969-971
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• 2000

In this paper, shortening of product life cycle and wide disposal of consumer product have given rise to many environmental problems, it needs to propose module design principle for saving of disassembly cost and reusing of used part and subassembly. To analyze characteristics of module for recycling, materials and function of part and subassembly must be classified. In disassembly process, a unit operation can be grasped for disassembly function, worker, tool and sorting process. As a result of applying module design principle, simpler structure and reduced structural interference can be realized for product structure. For disassembly, simpler disassembly and quicker disassembly can be obtained for recycling.

• 대한전기학회논문지
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• 제34권8호
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• pp.308-316
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• 1985

This paper proposes an analytic tool for long-term generation expansion planning based on the maximum principle. Many research works have been performed in the field of generation expansion planning. But few works can be found with the maxinmum principle. A recently published one worked by professor Young Moon Park et al. shows remarkable improvements in modeling and computation. But this modeling allows only thermal units. This paper has extended Professor Park's model so that the optimal pumped-storage operation is taken into account. So the ability for practical application is enhanced. In addition, the analytic supply-shortage cost function is included. The maximum principle is solved by gradient search due to its simplicity. Every iteration is treated as if mathematical programming such that all controls from the initial to the terminal time are manipulated within the same plane. Proposed methodology is tested in a real scale power system and the simulation results are compared with other available package. Capability of proposed method is fully demonstrated. It is expected that the proposed method can be served as a powerful analytic tool for long-term generation expansion planning.

• 한국환경과학회지
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• 제11권1호
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• pp.63-68
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• 2002

In this study, we examined statistical analysis between sewage plant operations parameters and effluent quality We got six components from principle component analysis of the operation parameters and secondary effluent quality. 91.8% of the total variance was explained by the six components. The components were identified in the following order : 1) organic matter removal by aeration basin microbe, 2) settleability on secondary clarifier load, 3) removal of nutrients, 4) microbial number increasement and species diversity, 5) microbial activity in aeration basin, 6) oxidation in aeration basin.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1410-1412
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• 1999

Protective relay for transformer operates in general by comparing with the differential current and the restraint current. These kinds of currents are changed on magnitude and phasor during the fault according to winding type and vector group. This paper presents the differential and restraint currents and operational principle of differential protective relay for two-winding and three-winding transformer with graphical model. It is developed using MATLAB for an educational purpose on engineer related in power system and protection in university and power utility including large factory.