• 대한전기학회논문지
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• 제35권6호
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• pp.217-225
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• 1986

This paper describes the Optimal PWM strategy to reduce a pulsating harmonic torque for a variable-speed drive of 3 phase induction motor. This paper suggests the new Optimal control theory which consists of 1) defining a performance index related to the unwanted effects of the voltage harmonics, (i.e., the components of pulsating harmonic torques) 2) achieving its minimization by a suitable choice of the switching patterns. (i.e., of the commutation angles) This PWM strategy is compared with the conventional SPWM strategy by numerical method. It is believed that this proposed strategy can reduce more harmonic components and pulsating harmonic torques than SPWM strategy. Also, We could verify the validety of the numerical method by a result of simulation analysis of a variable speed 3phase induction motor.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2018년도 춘계학술논문요약집
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• pp.94-95
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• 2018

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.124-127
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• 1997

In this paper, we propose a method of cooperative control based on immune system in distributed autonomous robotic system(DARS). Immune system is living body's self-protection and self-maintenance system. Thus these features can be applied to decision making of optimal swarm behavior in dynamically changing environment. For the purpose of applying immune system to DARS, a robot is regarded as a B lymphocyte(B cell), each environmental condition as an antigen, and a behavior strategy as an antibody respectively. The executing process of proposed method is as follows. When the environmental condition changes, a robot selects an appropriate behavior strategy. And its behavior strategy is simulated and suppressed by other robot using communication. Finally much simulated strategy is adopted as a swarm behavior strategy. This control scheme is based on clonal selection and idiotopic network hypothesis. And it is used for decision making of optimal swarm strategy.

• 한국해양공학회지
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• 제23권2호
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• pp.98-103
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• 2009

The resin infusion method is the latest technology of FRP laminating and cleaning to improve FRP hull quality. This method is focused on how to arrange infusion channels for the laminiating strategy. The laminating strategy using the resin infusion method has been utilized to complete the infusion work and remove the cavities on the FRP surface within the curing time. It is resulting from the arrangement of infusion and vacuum channels, the resin property, and the combination of FRP. This strategy has been depended on the field experience for manufacturing FRP without the resin infusion simulation. This study can help to improve the efficiency of FRP fabrication with the laminating strategy including the resin infusion simulation instead of the field experience.

• 대한전기학회논문지:전력기술부문A
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• 제55권10호
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• pp.410-417
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• 2006

Generally, the training set of maximum $m{\times}L(m+f)$ patterns in the pattern recognition method is required for the real-time bus reconfiguration strategy when a main transformer fault occurs in the distribution substation. Accordingly, to make the application of pattern recognition method possible, the size of the training set must be reduced as efficient level. This Paper proposes a methodology which obtains the minimized training set by applying the pattern clustering method to load patterns of the main transformers and feeders during selected period and to obtain bus reconfiguration strategy based on it. The MaxMin distance clustering algorithm is adopted as the pattern clustering method. The proposed method reduces greatly the number of load patterns to be trained and obtain the satisfactory pattern matching success rate because that it generates the typical pattern clusters by appling the pattern clustering method to load patterns of the main transformers and feeders during selected period. The proposed strategy is designed and implemented in Visual C++ MFC. Finally, availability and accuracy of the proposed methodology and the design is verified from diversity simulation reviews for typical distribution substation.

• 한국환경교육학회지:환경교육
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• 제5권1호
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• pp.71-88
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• 1993

This study was conducted to develop and effective strategy for environmental education. At first, the environmental education strategy through personalization of environment was proposed. Then students in a middle school participated the program according to the strategy and its. effect was investigated. The strategy was designed in basis of the role of the limbic system in brain and involved field-oriented experience such as viewing the non-personal environment as the personal environment. Gokneung stream was selected as the site to conduct this environmental education. Students investigated water quality by senses and biological method. The same content was taught for the classroom group and simple outdoor group selected for the comparison by traditional instructional method. The pre- and post-test by the instrument to test environmental attitude, qualitative questionnaire, cognitive test, the pre- and post-interview were conducted to investigate the effect the program. The achievement of the classroom group(personalization group). But the change of the attitude toward environment of personalization group between pre- and post-test was significantly higher than the classroom group. In qualitative questionnaire and pre- and post-interviews, attitude toward environment differed between two group. The behavioral change to discover and to solve environmental problems was demonstrated in case the personalization group, but was unclear in the classroom group. These results indicated the environmental education strategy through personalization of environment was an effective strategy to change the awareness, attitude and behavior toward the environment compared with a traditional teaching strategy.

• 경영과정보연구
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• 제27권
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• pp.53-69
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• 2008

In this paper we analyse performance of value strategy and moving average method among the non-financial listed companies whose fiscal year ends at December in the Korean Stock Exchange between 1996 and 2005. And we analyse combination investment performance of value investment and moving average method. After the analysis objective enterprises divide with the value stock and the growth stock, in accordance with moving average method we divide ascending stock and descending stock. And we compose 6 portfolios with combination of value stock, growth stock, ascending stock and descending stock. Using the difference of investment performance of these portfolios, when fundamental analysis and technical analysis method all considering we measure investment performance. The major findings of this research are as follows: First, the value strategy of buying value stocks and selling growth stocks were effective in the long-term investment. Second, using the moving average method, technical analysis were effective in the case of the short-term investment. Third, the portfolios combined fundamental analysis and technical analysis were more effective than investment performance of technical analysis.

• 한국정보통신학회논문지
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• 제14권10호
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• pp.2171-2179
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• 2010

전세계 국가는 21세기 메가 트렌드인 기술 융합(Technology Convergence) 추세에 발 맞춰 정보통신(IT)분야 미래비전 및 전략수립에 몰두하고 있다. 그리고, 자국의 국부 증대 및 신산업 창출을 위해 WWRF (Wireless World Research Forum), AmI (Ambient Intelligence), and mITF (mobile IT Forum)등의 공학적 시나리오를 기반으로 한 연구를 하고 있다. 하지만 국내의 경우 비전연구 및 전략수립에 대한 연구가 초보단계로 미래전략 수립에 능동적으로 대처하기에는 미흡하다는 지적이다. 따라서, 본 논문에서는 시나리오 기법을 활용한 선진국의 공학적인 미래전략연구 사례를 분석하고, 공학적인 시나리오 비전연구 방법을 제시한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.379-382
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• 1996

Evolution Strategy is used as an effective search algorithm in optimization problems and Sliding Mode Control is well known as a robust control algorithm. In this paper, we propose a Sliding Mode Control Method for robot manipulator using Evolution Strategy. Evolution Strategy is used to estimate Sliding Mode Control Parameters such as sliding surface gradient, continuous function boundary layer, unknown plant parameters and switching gain. Experimental results show the proposed control scheme has accurate and robust performances with effective search ability.

• 산업경영시스템학회지
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• 제22권52호
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• pp.297-309
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• 1999

Resource Constrained Dynamic Multi-Projects Scheduling(RCDMPS) is intended to minimize the total processing time(makespan) of two or more projects sequentially arriving at the shop under restricted resources. The aim of this paper is to develop the new Tabu Search heuristic for RCDMPS to minimize makespan. We propose the insertion method to generate the neighborhood solutions in applying the Tabu Search for the RCDMPS and the diversification strategy to search the solution space diversely. The proposed diversification strategy apply the dynamic tabu list that the tabu list size is generated and renewed at each iteration by the complexity of the project, and change the proposed tabu attribute. In this paper, We use the dynamic tabu list for the diversification strategy and intensification strategy in the tabu search, and compare with other dispatching heuristic method to verify that the new heuristic method minimize the makespan of the problem.