• Journal of the Korean Society for Precision Engineering
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• v.20 no.7
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• pp.193-200
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• 2003

The energy release rate for an interface crack in pseudo-isotropic dissimilar materials was obtained by the eigenfunction expansion method using the two-term William's type complex stress function. The complex stress function for pseudo-isotropic materials must be different from that for anisotropic materials. The energy release rate for an interface crack in pseudo-isotropic dissimilar materials was analyzed numerically by RWCIM. The results obtained were verified by comparing the other worker's results and discussed.

• JOURNAL OF ELECTRICAL WORLD
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• s.306
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• pp.70-72
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• 2002

작년 11월에 시작된 (일본)총합자원에너지 조사회 전기분과회에서의 $\ulcorner$일본 전력자유화 논의$\lrcorner$가 절정을 맞이한 가운데, 전력중앙연구소는 같은 11월에 $\ulcorner$에너지미래기술포럼$\lrcorner$을 개최하여 정책, 기술 양면에서 자유화 논의에 파문을 일으키는 제언(提言)을 하였다. 경제사회연구소를 중심으로 한 정책적 관점에서의 발표도 화제를 끌었으나, 기술적 관점에서의 과제 검토는 단순한 정책 논의가 아닌, 새로운 재료가 전력관계자에게 제시되었다고 할 수 있다. 경제분야에서 기술분야까지 폭넓게 커버 하고 있는 전력중앙연구소가 종합적으로 전력자유화의 과제를 평가한 것을 계기로, 앞으로 더욱 활발한 논의가 전개될 것으로 예상된다. 여기서는 특히 기술분야에 있어서 전력자유화에 대한 (일본)전력중앙연구소의 제언을 간추려 소개한다.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2003.05a
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• pp.391-398
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• 2003

지금까지 전범위 시뮬레이터에 의해 이루어진 원자력 및 화력발전소에서의 운전원교육은 실제 발전소 주제어실과 유사한 상황을 전개한다는 장점을 가지고 있으나, 주요 계통 및 기기에 대한 설명을 위해서는 교과서를 공유하거나, 강사의 지식을 칠판에 서술하는 방법으로만 진행되어 왔다. 전력연구원은 이러한 교육을 상당부분 강의실 컴퓨터를 이용하여 수행할 수 있다는데 착안하여 강의실용 가상발전소 교육훈련 시스템(VRPLANT)을 개발하였다. VRPLANT는 3차원 웹(Web) 기술을 적용하여 발전소 건물, 건물내의 주요기기 등을 3차원 가상공간에서 구축하여 Navigation할 수 있도록 하였으며, 주요기기에 대해서는 엔지니어링 데이터베이스가 연동되어 있어서 이동 중에 특정 기기를 선택하면 P＆ID, 논리도면, 기술설명서 등을 참조해 볼 수 있도록 개발하였다. 또한 기기들은 모니터상에서 분해 및 조립이 가능하여 기기의 형태, 내부구조 및 동작원리 등을 용이하게 이해할 수 있도록 하였다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.3
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• pp.185-193
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• 2016

In this study, the present deployment of the multiple wave energy converters (WECs) in a floating wind-wave hybrid power generation platform was estimated considering the interaction effect among WEC buoys. The interaction processes of multiple buoys were very complex, since scattered and radiated waves from each buoy affected the others in the array. The interaction analysis of the diffraction and radiation problem by the array of WECs was applied by matched eigenfunction expansion method (MEEM). The analytical solutions were compared with the results of numerical calculation based on WAMIT. The overall performance of 24 WECs installed in the hybrid power generation platform was evaluated by the q-factor representing the interaction effect among buoys.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.2
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• pp.103-111
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• 2014

The wave power, extracted from a circular array of small power buoys, is investigated under the potential theory. It is assumed that the buoy's radius, the draft, and the separation distance are much smaller than the water depth, the wave length, and the radius of a circular deployment area. The boundary value problem involving the macro-scale boundary condition on the mean surface covered by buoys is solved using the eigenfunction expansion method. The capture width, which is defined as the ratio of the extracted power to the wave power per unit length of the incident wave crest, is assessed for various combinations of packing ratio, radius of a circular array, and PTO damping coefficient. It is found that the circular array deployment is more effective in the viewpoint of efficiency than the single large buoy of the same total displaced volume.

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.545-550
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• 2023

A pretensioner is a safety device that protects occupants by pulling the seat belt in the event of a vehicle collision. However, since the pretensioner is driven by a explosive method, it is necessary to replace not only the gas generator but also all connecting parts including the manifold after an accident. Therefore, in this paper, we propose an elastic force-based pretensioner that can be used safely and semi-permanently. After analyzing the operating mechanism of the existing pretensioner from a thermodynamic/dynamic point of view, the spring stiffness that can be deployed within an appropriate operating time was determined by converting the gas explosion energy into elastic energy. In addition, the coil spring shape that satisfies the elastic stiffness was designed in consideration of the vehicle interior installation standard. Finally, the operating performance of the pretensioner driven by elastic force was verified through fabrication.

• Plant Journal
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• v.18 no.4
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• pp.66-72
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• 2023

In order to respond to the demand for flexible operation of thermal power generation, development of natural sliding pressure operation that minimizes throttle loss by opening the turbine control valve 100% and maximize power generation efficiency in conjunction with ESS in order to quickly respond to fluctuations in the system frequency is required. The logic development of natural sliding pressure operation with ESS was developed to modify the existing logic at the power plant's top-level control logic such as the unit master, the boiler master and the turbine master. Cooperative control algorithms that complement the advantages and disadvantages of ESS operation (quick response, limited capacity) and power plant operation (slow response, continuous operation) not only improve efficiency when applied to actual power plants, but also respond quickly and flexibly to load demands to ensure system stability.

• Journal of the Economic Geographical Society of Korea
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• v.24 no.2
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• pp.163-180
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• 2021

Nuclear power has been an attractive energy efficient and to the pressure with the climate change despite of its risks. There are safety, security, and environmental concerns with the nuclear radiation, but the techno-optimism forms the mainstream by experts and the state to be able to control and manage the risks yet occurred. The disastrous Chernobyl and Fukushima nuclear accidents brought about alternative action and thought including renewable energy expansion, efficient energy delivery and use, and enhancing stewardship to environmental carrying capacity. More significant alternative movement is sought by victims of nuclear radiation, technicians, and the general public who realized the pitfalls of expert and state centered policy formation. These laypersons become counter-expertise competent in recognizing local contamination and considering the risks and emotions seriously affecting peoples' everyday lives. They play important roles in the construction and legitimation of alternative knowledge about nuclear power widely realized across regions.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.15 no.3
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• pp.143-150
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• 2003

Based on the eigenfunction expansion method, the interaction between monochromatic waves and a partially immersed slotted plate with a back wall has been investigated. Analytical results show that the reflection coefficients by a partially immersed slotted plate depend on the porosity, immersed depth, chamber width, incidence angle and wave frequency. It is found that the reflection coefficient has minimum value within entire frequency range when the porosity has optimal value 0.1. Comparison between the analytical results and the experimental results(Zhu,2001) of reflection coefficients is made for various chamber widths, immersed depths and wave periods with good agreement. The present analytic method can account adequately for energy dissipation caused by flow separation behind a slotted plate and provide the design informations for the construction of slit caisson breakwater.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.1
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• pp.29-37
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• 2007

In this study, transmission and reflection of multi-directional random waves propagating over impermeable submerged breakwaters are calculated by using eigenfunction expansion method. A series of mutiderectional random waves is generated by using the Bretschneider-Mitsuyasu frequency and Mitsuyasu type directional spectrum. Strong reflection is occurred at the Bragg reflection condition of the peak frequency. If the row of breakwaters is fixed at 3 and the relative height of breakwater is fixed at 0.6, more than 25% of incident wave energy is reflected to offshore. It is also found that the reflection of directionally spreading random waves increases as the maximum spreading parameter $s_{max}$ increases.