• 한국태양에너지학회 논문집
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• 제31권3호
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• pp.42-47
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• 2011

Small hydropower resources for five major river systems have been studied. The model, which can predict flow duration characteristic of stream, was developed to analyze the variation of inflow caused from rainfall condition. And another model to predict hydrologic performance for small hydropower(SHP) plants is established. Monthly inflow data measured at Andong dam were analyzed. The predicted results from the developed models in this study show that the data were in good agreement with measured results of long term inflow at Andong dam. It was found that the models developed in this study can be used to predict the available potential and technical potential of SHP sites effectively. Based on the models developed in this study, the hydrologic performance for small hydropower sites located in river systems have been analyzed. The results show that the hydrologic performance characteristics of SHP sites had some difference between the river systems. Especially, the specific design flow and specific output of SHP sites located on North Han river and Nakdong river systems had large difference compared with other river systems.

• 전자공학회논문지SC
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• 제37권6호
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• pp.15-24
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• 2000

본 논문에서는 불확실성을 갖는 비선형 시스템의 출력 궤환 퍼지 H∞ 제어 문제를 고려한다. 비선형 시스템은 Takagi-Sugeno(T-S) 퍼지모델로 나타내고 제어기 설계는 퍼지모델을 이용하여 설계한다. Lyapunov 함수를 이용하여 퍼지모델에 대한 폐-루프 시스템의 안정성뿐만 아니라 외란감쇠에 대한 L₂ 이득 성능을 보장하는 충분조건을 유도한다. 유도된 조건식 으로부터 퍼지 H∞ 제어기가 존재할 충분조건을 선형 행렬부등식으로 나타내고, 이 선형 행렬부등식의 해로부터 제어기를 설계하는 알고리듬을 제시한다. 설계된 제어기는 비선형이며 퍼지 동작에 의해 자동적으로 조정된다.

• 한국방사선학회논문지
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• 제4권3호
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• pp.5-11
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• 2010

본 논문에서는 이중 에너지 디지털 래디오그래피를 위한 이중 모드 검출기 개발을 제안한다. 이중 에너지 래디오그래피 모듈의 설계를 위하여 상용 BIS(Baggage Inspection System)에서 사용되고 있는 X-선 발생장치의 스펙트럼과 이중 모드 검출기에 대한 특징 및 방사선적 특성을 분석하였다. 제안하는 영상 검출기 모듈은 BIS에서 활용되고 있는 X-선관을 대상으로 X-선 스펙트럼을 모사하고, 모사한 스펙트럼을 통하여 새롭게 제안하는 검출기 모듈의 방사선적 특성을 고찰하였다. X-ray를 이용한 실험에서 구리 필터의 두께 증가에 따라 저에너지 검출기(LED)와 고에너지 검출기(HED)의 출력신호의 차이는 같이 증가하였다. 특히 HED에서의 출력신호의 크기는 구리 필터 두께가 증가 할수록 감소함을 알 수 있었다.

• 조명전기설비학회논문지
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• 제23권11호
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• pp.9-21
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• 2009

This paper proposes the alternative observer and controller design scheme based on T-S fuzzy model. Nonlinear systems are represented by fuzzy models since fuzzy logic systems are universal approximators. In order to estimate the unmeasurable states of a given unknown nonlinear system, T-S fuzzy modeling method is applied to get the dynamics of an observation system. T-S fuzzy system uses the linear combination of the input state variables and the modeling applications of them to various kinds of nonlinear systems can be found. The proposed indirect adaptive fuzzy observer based on T-S fuzzy model can cope with not only unknown states but also unknown parameters. The proposed controller is based on a simple output feedback method. Therefore, it solves the singularity problem, without any additional algorithm, which occurs in the inverse dynamics based on the feedback linearization method. The adaptive fuzzy scheme estimates the parameters and the feedback gain comprising the fuzzy model representing the observation system. In the process of deriving adaptive law, the Lyapunov theory and Lipchitz condition are used. To show the performance of the proposed observer and controller, they are applied to an inverted pendulum on a cart.

• 대한안전경영과학회지
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• 제17권4호
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• pp.87-96
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• 2015

This study analyzed the safety management efficiency through input-oriented BCC Model using DEA by making of Models, in which this study selected the number of staff affiliated with the construction site, number of staff members on the construction team, and number of safety personnel as Input Factor, along with the number of disaster victims and zero-accident accomplished hours as output elements, targeting 40-or-so apartment building construction sites which are being built by 3 domestic construction companies. As a result of efficiency, it was 0.643, the number of efficient DMU was 4. In the aspect of returns to scale, 21 construction sites(52.5%) found to be in a state of increasing returns while 14 construction sites(35%) was in a state of Decreasing returns. The reason for inefficiency was found to lie in technical factors in case of 30 construction sites(75%). Lastly, inefficient DMU is in need of 38.9 % and 66% reduction in site personnel and safety personnel. Based on study results, the 29 construction sites accounting for 72.5% of DMU for safety management efficiency evaluation object turned out to do inefficient safety management that doesn't fit the size of each company.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
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• pp.235-240
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• 2011

Small hydropower resources for five major river systems have been studied. The model, which can predict flow duration characteristic of stream, was developed to analyze the variation of inflow caused from rainfall condition. And another model to predict hydrologic performance for small hydropower(SHP) plants is established. Monthly inflow data measured at Andong dam were analyzed. The predicted results from the developed models in this study showed that the data were in good agreement with measured results of long term inflow at Andong darn. It was found that the models developed in this study can be used to predict the available potential and technical potential of SHP sites effectively. Based on the models developed in this study, the hydrologic performance for small hydropower sites located in river systems have been analyzed. The results show that the hydrologic performance characteristics of SHP sites have some difference between the river systems. Especially, the specific design flowrate and specific output of SHP sites located on North Han river and Nakdong river systems have large difference compared with other river systems.

• Journal of Electrical Engineering and Technology
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• 제7권6호
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• pp.852-858
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• 2012

This paper describes evaluation results of the wind power penetration limit (WPPL) and the wind energy penetration (WEP) in the Mongolian central power system (MCPS). A wind power plant (WPP) in a power system possesses an output power limit because the power system must maintain a balance between the generation and consumption of electricity at all times in order to achieve an adequate level of quality. The instantaneous penetration limit (IPL) of wind generation at a load is determined as the minimum of the three technical constraints: the minimum output, the ramp rate capability, and the spinning reserve of the conventional generating units. In this paper, a WPPL is defined as the maximum IPL divided by the peak load. A maximal variation rate (VR) of wind power is a major factor in determining the IPL, WPPL, and WEP. This paper analyzes the effects of the maximal VR of wind power on the WPPL, WEP, and capacity factor (CF) in the MCPS. The results indicate that a small VR can facilitate a large amount of wind energy while maintaining a high CF with increased wind power penetration.

• 대한산업공학회지
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• 제41권5호
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• pp.425-438
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• 2015

This study proposes a three-stage model of R&BD performance which captures commercialization outcomes as well as conventional R&D performance. The model is composed of three factors : inputs (R&D budgets and researchers), outputs (patents and papers), and outcomes (technical fees, products sales, and cost savings). Three stages are defined for each transformation process between the three factors : efficiency stage from input to output (stage 1), effectiveness stage from output to outcome (stage 2), and productivity stage from input to outcome (stage 3). The performance of each stage is measured by data envelopment analysis (DEA). DEA is a non-parametric efficiency measurement technique that has widely been used in R&D performance measurement. We measure the performance of 171 projects of 6 public R&BD programs managed by Seoul Business Agency using the proposed three-stage model. In order to provide a balanced and holistic view of R&BD performance, the R&BD performance map is also constructed based on performance of efficiency and productivity stages.

• 한국산학기술학회논문지
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• 제15권10호
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• pp.6264-6269
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• 2014

본 논문에서는 UWB 대역에 관한 해외 각국의 주파수 정책에 대해 살펴보고 그 결과를 우리나라 실정에 적용할 수 있는 방안에 대해 연구를 수행하였다. 그 결과 현재 우리나라의 기술 기준은 미국이나 유럽 등의 외국과 달리 주로 통신 서비스분야에서 사용할 수 있도록 규정되어 있음을 확인하였다. 그러나 UWB의 서비스 영역이 다양한 분야로 확대되고 있어 이러한 규정은 국내 산업의 보호 및 활성화를 저해하는 요소로 작용하고 있다. 따라서 외국의 사례와 같이 방송 통신을 제외한 다양한 영역에서 사용할 수 있도록 출력기준만 만족하면 언제, 어디서든지 사용할 수 있는 비허가 무선기기항목으로 지정하여 관련 산업보호 및 활성화를 도모해야 할 것으로 사료된다.

• KEPCO Journal on Electric Power and Energy
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• 제5권3호
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• pp.215-222
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• 2019

This work is experimental study of 10 kW specialized Combined Ocean Thermal Energy Conversion. We propose a C-OTEC technology that directly uses exhaust thermal energy from power station condensers to heat the working fluid (R134a), and tests the feasibility of such power station by designing, manufacturing, installing, and operating a 10 kW-pilot facility. Power generation status was monitored by using exhaust thermal energy from an existing power plant located on the east coast of the Korean peninsula, heat exchange with 300 kW of heat capacity, and a turbine, which can exceed enthalpy efficiency of 45%. Output of 8.5 kW at efficiency of 3.5% was monitored when the condenser temperature and seawater temperature are $29^{\circ}C$ and $7.5^{\circ}C$, respectively. The evaluation of the impact of large-capacity C-OTEC technology on power station confirmed the increased value of the technology on existing power generating equipment by improving output value and reducing hot waste water. Through the research result, the technical possibility of C-OTEC has been confirmed, and it is being conducted at 200 kW-class to gain economic feasibility. Based on the results, authors present an empirical study result on the 200 kW C-OTEC design and review the impact on power plant.