• 전기학회논문지
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• 제58권6호
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• pp.1093-1099
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• 2009

Alternative energy sources such as renewable energy like solar power systems, wind power systems, or fuel cell power systems has been the rising issue in the electrical power system. This paper discusses an economic study analysis of fuel cells in the korean electricity market. It includes the basic concept of a fuel cell and the korean electricity market. It also describes the need of renewable energy and how the fuel cell is connected with the local grid. This paper shows the impact of production and recovering thermal energy of a grid-connected fuel cell power system. The profit maximization approach has been structured including electrical power trade with the local grid and heat trade within the micro-grid. The strategies are evaluated using a local load that uses electric and thermal power which has different patterns between summer and winter periods. The solution algorithm is not newly developed one, but is solved by an application called GAMS. Results indicate the need and usefulness of a fuel cell power system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권11호
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• pp.4367-4386
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• 2015

The concept of Internet of Things (IoT) has shed new light on WSN technologies. MAC protocol issues improving the network performance are important in WSNs because of the increase in demand for various applications to secure spectrum resources. Cognitive radio (CR) technology is regarded as a solution to the problems in this future wireless network. In recent years, energy efficiency has become an issue in CR networks. However, few relevant studies have been conducted. In this paper, an energy-efficient non-overlapping channel MAC (ENC-MAC) for CR-enabled sensor networks (CRSNs) is proposed. Applying the dedicated control channel approach, ENC-MAC allows the SUs to utilize channels in a non-overlapping manner, and thus spectrum efficiency is improved. Moreover, the cooperative spectrum sensing that allows an SU to use only two minislots in the sensing phase is addressed to en-hance energy efficiency. In addition, an analytical model for evaluating the performance, such as saturation throughput, average packet delay, and network lifetime, is developed. It is shown in our results that ENC-MAC remarkably outperforms existing MAC protocols.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(2)
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• pp.429-434
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• 1996

K-REM［1］, which is under development as a realistic evaluation model of large break LOCA, is applied to the analysis of cold leg guillotine break of Ulchin 3&4. Fuel parameters on which statistical analysis of their effects on the peak cladding temperature (PCT) are made and system parameters on which the concept of limiting value approach (LVA) are applied, are determined from the single parameter sensitivity study. 3 parameters of fuel gap conductance, fuel thermal conductivity and power peaking factor are selected as fuel related ones and 4 parameters of axial power shape, reactor power, decay heat and the gas pressure of safety injection tank (SIT) are selected as plant system related ones. Response surface of PCT is generated from the plant calculation results and on which Monte Carlo sampling is made to get plant application uncertainty which is statistically combined with code uncertainty to produce the 95th percentile PCT. From the break spectrum analysis, blowdown PCT of 1350.23 K and reflood PCT of 1195.56 K are obtained for break discharge coefficients of 0.8 and 0.5, respectively.

• 방사성폐기물학회지
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• 제13권4호
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• pp.283-293
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• 2015

고준위폐기물처분장에서 완충재는 공학적방벽의 주요 구성요소 중 하나이다. 본 연구에서는 국 내외의 완충재 요구사항과 성능기준을 분석하고, 우리나라 고준위폐기물처분장에 적합한 완충재 개념 도출을 위한 접근방안을 제시하였다. 완충재의 주요 성능기준 인자항목으로, 수리전도도, 핵종 저지능, 팽윤압, 열전도도, 역학적 특성치(mechanical properties), 유기물함량(organic carbon content), 일라이트화 속도(illitization rate) 등을 고려하였다. 우리나라 고준위폐기물처분장 완충재 물질로서 국산 벤토나이트(Ca-벤토나이트)와 대안재로 MX-80 벤토나이트(Na-벤토나이트)를 제안하였다. 완충재의 기술사양은 Ca-벤토나이트 경우엔 우리나라의 성능기준을, Na-벤토나이트의 경우는 스웨덴의 성능기준을 보수적으로 만족하는 값으로 설정하였다. 완충재의 두께는 전단거동, 핵종 유출, 열전도의 측면에서 평가하여 결정하였으며, 평가결과 완충재의 두께는 0.25 ~ 0.5 m 사이가 적절하였다. 그러나 최종적인 완충재의 두께는 향후 보다 심도 있는 열-수리-역학적 평가와 경제적, 공학적 측면을 고려하여 결정하여야 할 것이다.

• 기술혁신연구
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• 제29권1호
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• pp.1-38
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• 2021

본 논문에서는 에너지 섹터의 혁신성 제고를 위한 리빙랩(Living Labs) 활용 전략 수립에 관한 탐색적 분석 연구를 수행하였다. 기존 연구문헌을 통해 이론적 배경이 되는 리빙랩의 개념, 필수 구성요소, 혁신성 특성과 에너지 섹터의 혁신 이슈 유형을 확인할 수 있었다. 이를 토대로 리빙랩 필수 구성요소의 맞춤형 전략 수립과 혁신성 제고와의 연관성, 에너지 섹터에서의 혁신 이슈에 대한 접근으로 리빙랩 활용 가능성에 대해 에너지 리빙랩 사례 연구(해외 8건, 국내 1건)을 통해 분석되었다. 연구 결과, 리빙랩 필수 구성요소의 맞춤형 전략 수립이 혁신성 제고에 동인으로 작용 될 수 있으며, 리빙랩이 에너지 섹터의 혁신 이슈(수요관리, 공급기술, 기술사업화 촉진 및 수용성, 기술정책)에 대한 접근 방법론으로 효과적으로 활용 될 수 있음을 확인되었다. 사례연구 결과 기반으로 혁신성 기여 관점에서 리빙랩 사례별 동인을 도출하고 에너지 혁신이슈별 리빙랩 활용 전략을 수립하였다. 본 연구는 에너지 섹터에서의 혁신이슈에 대한 접근으로 리빙랩 모델의 활용 전략과 그 가치에 대한 탐색적, 기술적 분석 연구로서 종래에 시도되지 않았던 리빙랩 활용 전략 프레임워크를 제공할 수 있고, 에너지 리빙랩 활성화와 네트워크 형성에도 기여될 수 있다는 점에서 학술적·실용적·정책적 함의가 있다고 볼 수 있다.

• Asian Journal of Innovation and Policy
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• 제5권1호
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• pp.92-115
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• 2016

This paper presents how Korea succeeded in developing an indigenous nuclear power plant model over fifty years. Long-lasting national R&D for technical progress and the Korean government for managerial process were the two pillars in the build-up of indigenous Nuclear Power Plant (NPP) technological capabilities. The concept of technological capabilities is used to examine its evolutionary process with a qualitative and longitudinal approach. The government had a developing country ambition to formulate a strategic plan for technical self-reliance on nuclear power plant while establishing the country’s institutions and organization structure for the plan. Under the government leadership, it was national R&D that led to the resolution of a good number of technological problems, efficiently, by absorbing imported technologies and effectively adapting them to local circumstances.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.91-93
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• 2008

A Buoyant Hybrid Power Generation System (BHPGS) described in this paper, is a conceptual approach to a hybrid solar-wind power generation in the near sea. The primary purpose of the BHPGS is given to improve utilization of solar cell modules. Main components of the BHPGS include a solar cell module, buoyant object, power generator, and support assembly including weight. Components such a generator controller, DC/AC converter, etc., are not configured in the current BHPGS because they can easily be purchased as a commercial-off-the-shelf product. In addition, some of the BHPGS applications are discussed.

• ETRI Journal
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• 제33권3호
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• pp.407-414
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• 2011

In an effort to reduce energy consumption, research into adaptive power management in real-time systems has become widespread. In this paper, a novel dynamic voltage scaling scheme is proposed for multiprocessor systems. Based on the concept of the Nash bargaining solution, a processor's clock speed and supply voltage are dynamically adjusted to satisfy these conflicting performance metrics. In addition, the proposed algorithm is implemented to react adaptively to the current system conditions by using an adaptive online approach. Simulation results clearly indicate that the superior performance of the proposed scheme can strike the appropriate performance balance between contradictory requirements.

• International Journal of Fluid Machinery and Systems
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• 제4권1호
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• pp.114-132
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• 2011

We have proposed a new approach based on energy gradient concept for the study of flow instability and turbulent transition in parallel flows in our previous works. It was shown that the disturbance amplitude required for turbulent transition is inversely proportional to Re, which is in agreement with the experiments for imposed transverse disturbance. In present study, the energy gradient theory is extended to the generalized curved flows which have much application in turbomachinery and other fluid delivery devices. Within the frame of the new theory, basic theorems for flow instability in general cases are provided in details. Examples of applications of the theory are given from our previous studies which show comparison of the theory with available experimental data. It is shown that excellent agreement has been achieved for several configurations. Finally, various prediction methods for turbulent transition are reviewed and commented.

• 한국실내디자인학회논문집
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• 제25호
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• pp.236-244
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• 2000

The concept of the true house' is based on the balance of a person's life and nature and represents the life in which lies an organic harmony between environment and ecology. However, humans have always been in a position of dominance over nature and with their developments have brought on much destruction and corruption to the ecosystem. With this, the position of the true house has intensified and the ecological approach of architecture has started to come into consideration as its alternative plan. Accordingly, it is essential to reconstruct and take on a new perspective of nature. The conversion to a more Oriental approach, which dwells in the adaptation and harmony of nature, is especially sufficient to the ecological aspect of architecture. From this we can realize that the ecological approach is none other than a modern interpretation of what our ancestors have lived by. In other words, an architectural concept deriving from the adaptation of climate, season, and nature-the coexistence of man and nature. From an ecological point of view, the idea of favoring nature in the traditional house can be found in the inclination of being one with nature by adapting to its geographical and preferable climate conditions. This results in the use of natural energy, the use of natural resources, the organic connection between the inner and outer natural space, and the application of nature itself. By approaching these elements from a modern point of view and applying it to the current time, we can open up the door to a more lasting human-environment based ecological position of architecture where our own climatic characteristics and traditions can be reflected in the pursuit of harmony between man and nature.