• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.39-44
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• 2008

The heat exchange between the Borehole Heat Exchanger(BHE) and the surrounding ground depends directly on ground thermal conductivity k at the certain site. The k is thus a key parameter in designing BHE and coupled geothermal heat pump systems. Currently, although a thermal hydraulic response test(TRT) is mostly used in practice, the thermal hydraulic TRT needs additional power and is generally time-consuming. A new, simple wireless P/T probe for a hi-speed k determination was introduced in this paper. This technique using a wireless P/T probe is less time-consuming and requires no external source of energy for measurement and predicts local thermal properties by measuring soil temperatures along the depth. Measured temperature data along the depth was analyzed. In order to verify the new technique for the determination of ground thermal conductivity, ground thermal conductivity k that calculated from the measured temperature data using a wireless P/T probe was compared with one obtained from conventional hydraulic TRT. When comparing the average k of two methods, the relative error was approximately 10%. As a result, the electronic TRT can replace the conventional hydraulic TRT method after carrying out the additional research on a lot of sites.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.3
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• pp.243-246
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• 2019

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.139.1-139.1
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• 2011

정부는 국가에너지 기본계획을 통하여 2030년까지 1차 에너지에 대해 신재생에너지 비중을 11%까지 확대하겠다는 목표를 설정하였다. 이에 대한 일환으로 신재생에너지 지방보급 사업 등 지역 별로 신재생에너지에 관한 투자 및 보급이 활발하게 진행되고 있는 상황이다. 더불어, 각 지방자치단체에서도 지역에 맞는 신재생에너지 계획을 수립하여 신재생에너지를 보급하고자 노력하고 있다. 신재생에너지 사업은 지역의 경제발전과 밀접한 연관을 가지고 있기 때문에 그 중요성이 더욱 부각되고 있는 실정이다. 본 연구에서는 우리나라 각 지역별 신재생에너지 계획안을 검토하여 어떠한 에너지원에 중점을 두고 사업을 추진하고 있는지 그 현황을 파악하고자 한다. 또한 이들 지역의 신재생에너지 계획안이 해당 지역의 신재생에너지 잠재량과 같은 지역의 특성을 잘 반영하고 있는지, 해당 지역의 신재생에너지 현황은 어떠한지 에너지기술연구원과 에너지관리공단의 관련 자료를 참고하여 검토할 것이다. 이를 통해 궁극적으로 각 지역의 신재생에너지 계획이 해당 지역이 보유하고 있는 자원(자연자원, 인력자원, 경제적 재원 등)을 효율적으로 활용하고 있는지 분석하고자 한다. 본 연구의 결과는 기존의 지역별 신재생에너지 계획을 평가하는데 사용될 수 있으며, 향후 지역 및 국가단위의 에너지 계획 수립에 참고자료로 활용될 수 있을 것이다.

• New & Renewable Energy
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• v.16 no.2
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• pp.20-27
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• 2020

According to "The Renewable Energy 3020 Implementation Plan", offshore wind power accounts for 12 GW of the total new capacity of 48.7 GW. Like the south-west 2.5 GW offshore wind farm case, government-led development has had difficulty in securing the residents' acceptability. This study contributes to the study of local acceptance by analyzing the perceptions of Maldo residents. To this end, in-depth interviews were conducted with the head of a village and fishing village chief, and the entire contents of the interview were revised and analyzed. The cognitive structure of the stakeholders could be confirmed using semantic network analysis, which analyzes the network structure among words. Based on the analysis results, focusing on the identity frames related to the compensation process from previous national projects, gain vs. loss frames act as the dominant frame in terms of profits from offshore wind turbines. To invigorate offshore wind farms, the policy implications as follows. First, a negotiation organization should be organized to deal with strategic opposition by fishes. Second, installing offshore wind farms on a public water body will result in demands for compensation from various actors, and a licensed fishing territory as an offshore wind farm installation site should be considered.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.9
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• pp.504-511
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• 2000

The reliability of system is to become a important concern in developed industry. The controller based on the reliability is so important position. PPC(Plant Protection Controller) is for plant protection and human life by fault detection and control action against the transient condition of plant. The protection system of the nuclear reactor and chemical reactor are representative of PPC. This paper presents analysis of PPC relaibility formal problem statement of optimal redundancy based on the reliability for PPC. And the problem is optimized by genetic algorithm, The genetic algorithms is useful algorithm in case of large searching complex gradient existence local minimum. The genetic algorithms is useful algorithm is case of large searching complex gradient existence local minimum. The ability and effectiveness of the proposed optimization is demonstrated by the target reliability of one channel. PPC. using the failure rate based on the MIL-HDBK-217

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.3
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• pp.81-88
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• 2012

In this paper, we propose a novel speech enhancement algorithm for effective noise suppression in various noisy environments. In the proposed method, to result in improved decision performance for speech and noise segments, local speech absence probability (LSAP, local SAP) based on Teager energy of noisy speech is used as the feature parameter for voice activity detection (VAD) in each frequency subband instead of conventional LSAP. In addition, The presented method utilizes global SAP (GSAP) derived in each frame as the weighting parameter for the modification of the adopted TE operator to improve the performance of TE operator. Performances of the proposed algorithm are evaluated by objective test under various environments and better results compared with the conventional methods are obtained.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.9 no.3
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• pp.181-189
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• 2011

The smooth construction and operation of nuclear facilities requires understanding and support of both the local residents and the national people. It is essential that our country, which should maintain using nuclear energy for national energy security and economic growth, shall improve the social acceptance of nuclear energy. In order to identify the level of social acceptance of nuclear energy, this study investigated the perception of the local residents in Gyeongju and the public in other areas on a nuclear power plant and a low- and intermediate-level radioactive waste disposal facility through an individual interview. The subjects of the investigation were 450 persons. This study identified that perceptions of the respondents were somewhat dependent on the residential area, and derived the implications to be reflected in establishing the customized public-relation strategies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.3
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• pp.1346-1351
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• 2012

In order to evaluate the local scour around offsshore wind foundation, mono pile and jacket foundation were simulated by using FLOW-3D. Numerical analysis results show that local increases of velocity around mono pile and jacket foundation was developed but velocity decreases in backward of pile and leg due to the wake vortex was observed. Local increases of velocity around foundation and scouring of jacket is more significant than that of mono pile, since jacket is the complex structure and has the interference effect with legs. Therefore, in order to evaluate the scour and design the scour protection method, the form and shape of substructures of offshore wind should be considered.

• Journal of Mechanical Science and Technology
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• v.18 no.10
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• pp.1782-1798
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• 2004

A numerical study of a natural convection in a rectangular cavity with the low-Reynolds-number differential stress and flux model is presented. The primary emphasis of the study is placed on the investigation of the accuracy and numerical stability of the low-Reynolds-number differential stress and flux model for a natural convection problem. The turbulence model considered in the study is that developed by Peeters and Henkes (1992) and further refined by Dol and Hanjalic (2001), and this model is applied to the prediction of a natural convection in a rectangular cavity together with the two-layer model, the shear stress transport model and the time-scale bound ν$^2$- f model, all with an algebraic heat flux model. The computed results are compared with the experimental data commonly used for the validation of the turbulence models. It is shown that the low-Reynolds-number differential stress and flux model predicts well the mean velocity and temperature, the vertical velocity fluctuation, the Reynolds shear stress, the horizontal turbulent heat flux, the local Nusselt number and the wall shear stress, but slightly under-predicts the vertical turbulent heat flux. The performance of the ν$^2$- f model is comparable to that of the low-Reynolds-number differential stress and flux model except for the over-prediction of the horizontal turbulent heat flux. The two-layer model predicts poorly the mean vertical velocity component and under-predicts the wall shear stress and the local Nusselt number. The shear stress transport model predicts well the mean velocity, but the general performance of the shear stress transport model is nearly the same as that of the two-layer model, under-predicting the local Nusselt number and the turbulent quantities.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.10
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• pp.795-803
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• 2015

The boundary layer developing over the suction surface of a first-stage turbine blade for power generation has been investigated in this study. For three locations selected in the region where local thermal load changes dramatically, mean velocity, turbulence intensity, and one-dimensional energy spectrum are measured with a hot-wire anemometer. The results show that the suction-surface boundary layer suffers a transition from a laminar flow to a turbulent one. This transition is confirmed to be a "separated-flow transition", which usually occurs in the shear layer over a separation bubble. The local minimum thermal load on the suction surface is found at the initiation point of the transition, whereas the local maximum thermal load is observed at the location of very high near-wall turbulence intensity after the transition process. Frequency characteristics of turbulent kinetic energy before and after the transition are understood clearly from the energy spectrum data.