• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.235-239
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• 2005

This paper gives a field-test method and result of PQM(Power Quality Meter) and PQMS(Power Quality Management System). The field-test was carried out as our own method. So, the test method has several kinds of improvement in this paper because it is first time to try the field-test of the equipment. However, we expect that the test result of PQM & PQMS has been used as a reference data which makes a scheme of evaluating performance of the equipment that has been used or is developed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.10
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• pp.102-108
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• 2011

The existing power flow has a single direction to the line end but the bidirectional power flow will possibly occur depending on the output capacity in the 22.9[kV] distribution power system connected with the dispersed generation(DG). So these characteristics would influence the power system management. The DG have many advantages such as assistance source, Load share etc. So the utility must apply the bidirectional protection system so as to maximize an advantage of DG. This paper describes the field test case of bidirectional protective device in order to investigate the device performance when applied to bidirectional power system. We have tested in the power system test site of KEPCO and these tests provide the basis for performance verification test of bidirectional protective device in the power system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.2
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• pp.7-13
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• 2013

The portion of lighting power consumption for our country is up to 20~30% of the total amount. Currently, most of the DSM(Demand side management) of lighting power is delivered in supply of high efficient lighting to customers. On the contrary, applications of lighting power to power load leveling are still rare. In this paper, the simulations for various control types of lighting power for load leveling are tried, and we obtained the cost effective and optimal control method through that. This simulation was executed in test office with fluorescent light by us based on applying 8 control types(on, off & dimming), considering customers' satisfaction, for instance, minimum intensity of illumination allowed. According to the result of this test, we found that mixed type(chessboard(on-off) plus dimming control(10%)) is most effective.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.4
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• pp.383-389
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• 2004

Magnetic refrigeration is based on the magnetocaloric effect (MCE) - the ability of some materials to heat up when magnetized and cool down when removed from the magnetic field. The available techniques for studying the MCE we: (1) direct measurements by monitoring the change in the material's temperature during the application or removal of the magnetic field; and (2) indirect calculations from the experimental data of magnetization and/or specific heat as a function of the temperature and magnetic field. The MCE of gadolinium (Gd) has been demonstrated by direct measurements of temperature change, and isothermal magnetic entropy changes and adiabatic temperature changes have been calculated.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.332-337
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• 2009

The importance of the evaluation and verification of small-size cogeneration system has been emphasized because there is no KS-code related to the small-size cogeneration system. The evaluation method of small-size engine cogeneration system, regarding Japanese standard JIS B-8122 and international standard organization, ISO-8528, was applied to the system. The evaluation methods, start-test, rapid-load-up and rapid-load-down, etc. were executed at the system, and reasonable results were acquired. The electrical and thermal efficiencies were executed and analyzed at various load conditions. The NOx emission at various load condition was also measured. Finally, the gas engine cogeneration system was installed to a site for actual usage and it was continually operated during more than 6 months as the site condition.

• The Korean Journal of Financial Management
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• v.15 no.1
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• pp.245-261
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• 1998

본 논문은 다기간 대리모형에서 나타날 수 있는 대리비용 중에서 대리인과 위임자의 의사 결정고려기간(decision-making horizon)의 차이로 인해서 발생할 수 있는 과소투자유인을 연구 대상으로 하고 있다. 대리인인 경영자는 자신의 명성을 고려해서 투자효과가 자신의 임기내에 나타나는 투자안에 높은 관심을 가질 것이다. 그런데 계속기업을 전제로 하면 대리인인 경영자는 위임자인 주주보다 투자의사결정시 고려하는 기간이 짧아서 과소투자의 가능성이 존재한다. 동적최적화 기법을 이용한 이론적 모형의 결과도 대리계약기간이 짧을수록 투자수준이 낮을 것으로 나타났다. 이러한 내용을 한국상장기업들을 대상으로 임원근속기간과 설비투자수준의 관계에 대해서 실증분석한 결과, 이론적 기대와 일치하지만 통계적 유의성은 낮은 편이었다. 이같은 결과는 전문경영체제가 확립되어 있지 않은 한국기업환경의 특성에 기인한다고 생각된다.

• Proceedings of the KAIS Fall Conference
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• 2011.05a
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• pp.186-189
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• 2011

최근 전력의 효율적 사용을 통해 에너지절약과 발전효율을 향상시키기 위해 국가적으로 스마트그리드 실증 사업이 추진되고 있다. 또한 스마트그리드 특별법, 기술개발 지원 등 제도적 지원을 통해 기술 보급 사업을 실시할 예정이다. 하지만 스마트그리드는 전력의 생산, 전송 및 사용을 중심으로 투자 및 개발에 집중되고 있고 전기안전의 확보에 대한 정책 및 기술적 투자가 부족한 실정이다. 따라서 본 논문에서는 스마트그리드의 성공적 구축을 지원하기 위해 추진되어야 할 고객전기설비 안전성 확보 정책 방향을 제안하였다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.2
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• pp.196-203
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• 2012

Energy foundations and other thermo-active ground structure, energy wells, energy-slab, and pavement heating and cooling represent an innovative technology that contributes to environmental protection and provides substantial long-term cost savings and minimized maintenance. This paper focuses on earth-contact concrete elements that are already required for structural reasons, but which simultaneously work as heat exchangers. Pipes, energy slabs, filled with a heat carrier fluid are installed under conventional structural elements, forming the primary circuit of a geothermal energy system. The natural ground temperature is used as a heat source in winter and a heat sink in summer. The geothermal heat pump system with energy-slab represented very high heating and cooling performance due to the stability of EWT from energy slab. However, the performance of it seemed to be affected by the atmospheric air temperature.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.453-458
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• 2007

The importance of the evaluation and verification of small-size cogeneration system has been emphasized because there is no KS-code related to the small-size cogeneration system. The evaluation method of small-size engine cogeneration system was investigated by the reference of Japan evaluation code, JIS B-8122 and international standard organization, ISO-8528. Evaluation method was introduced such as start-test, rapid-load-up and rapid-load-down, etc. The evaluation method was applied to the 300kW small-size gas engine cogeneration system newly developed. The precise and strict evaluation and verification of the system will help the developing cogeneration system to optimum condition. It will also be a base document of KS-Code.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.629-634
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• 2007

The Alternative energy has lately attracted considerable attention due to the high oil price and environment problem. In this study, field test of facility for using the geothermal energy source from water-purifying device was constructed and monitoring devices are installed to estimate the efficiency of this system. Initial installation cost can be saved efficiently by connecting a heat pump system into the existing pumping well in site of water-purifying in Cheongju. One set of monitoring results during summer was presented and analyzed.