• 대한안전경영과학회지
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• 제22권1호
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• pp.1-8
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• 2020

Maintenance of power distribution facilities is a significant subject in the power supplies. Fault caused by deterioration in power distribution facilities may damage the entire power distribution system. However, current methods of diagnosing power distribution facilities have been manually diagnosed by the human inspector, resulting in continuous pole accidents. In order to improve the existing diagnostic methods, a thermal image analysis model is proposed in this work. Using a thermal image technique in diagnosis field is emerging in the various engineering field due to its non-contact, safe, and highly reliable energy detection technology. Deep learning object detection algorithms are trained with thermal images of a power distribution facility in order to automatically analyze its irregular energy status, hereby efficiently preventing fault of the system. The detected object is diagnosed through a thermal intensity area analysis. The proposed model in this work resulted 82% of accuracy of detecting an actual distribution system by analyzing more than 16,000 images of its thermal images.

• 한국정밀공학회지
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• 제27권1호
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• pp.91-98
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• 2010

The increasing of power and processing speed and miniaturization of central processor unit (CPU) used in electronics equipment requires better performing thermal management systems. A typical thermal management package consists of thermal interfaces, heat dissipaters, and external cooling systems. There have been a number of experimental techniques and procedures for estimating thermal conductivity of thin, compressible thermal interface material (TIM). The TIM performance is affected by many factors and thus TIM should be evaluated under specified application conditions. In compact packaging of electronic equipment the chip is interfaced with a thin heat spreader. As the package is made thinner, the coupling between heat flow through TIM and that in the heat spreader becomes stronger. Thus, a TIM characterization system for considering the heat spreader effect is proposed and demonstrated in detail in this paper. The TIM test apparatus developed based on ASTM D-5470 standard for thermal interface resistance measurement of high performance TIM, including the precise measurement of changes in in-situ materials thickness. Thermal impedances are measured and compared for different directions of heat dissipation. The measurement of the TIM under the practical conditions can thus be used as the thermal criteria for the TIM selection.

• 마이크로전자및패키징학회지
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• 제20권3호
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• pp.1-6
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• 2013

TSV는 그동안 3D IC 적층을 하는데 핵심 기술로 많이 연구되어 왔고, RC delay를 줄여 소자의 성능을 향상시키고, 전체 시스템 사이즈를 줄일 수 있는 기술로 각광을 받아왔다. 최근에는 TSV를 전기적 연결이 아닌 소자의 열관리를 위한 구조로 연구되고 있다. TSV를 이용한 liquid cooling 시스템 개발은 TSV 제조, TSV 디자인 (aspect ratio, size, distribution), 배선 밀도, microchannel 제조, sealing, 그리고 micropump 제조까지 풀어야 할 과제가 아직 많이 남아있다. 그러나 TSV를 이용한 liquid cooling 시스템은 열관리뿐 아니라 신호 대기시간(latency), 대역폭(bandwidth), 전력 소비(power consumption), 등에 크게 영향을 미치기 때문에 3D IC 적층 기술의 장점을 최대로 이용한 차세대 cooling 시스템으로 지속적인 개발이 필요하다.

• The Journal of Asian Finance, Economics and Business
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• 제9권5호
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• pp.475-486
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• 2022

The purpose of this paper is to examine the use of material flow cost accounting (MFCA) in Vietnam's coal-fired thermal power plants. This study is based on the contingency and system theories to explain the application of management tools and analyze steps of input, output, and process in manufacturing. Costs in producing process-based MFCA include material cost, energy cost, system cost, and waste management cost. The exploratory case study methodology is used to describe and answer two questions, namely "How coal flow cost is recognized?" and "Why waste in material consumption can be harmful to the environment?". By analyzing the Quang Ninh and Pha Lai coal-fired thermal power plants that are the typical plants, this paper identifies the flow of primary material in these plants as a basis for determining losses for the business. The material flow of coal-fired thermal power plants provides the basis for the use of the MFCA. The manufacturing of electrical items in these plants is divided into four stages, each with its own set of losses. As a result, some phases in the application of MFCA are suggested, as well as some other elements required for MFCA application in coal-fired thermal power plants.

• 한국산학기술학회논문지
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• 제12권12호
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• pp.5457-5463
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• 2011

본 연구의 목적은 이산화탄소를 적용한 자동차용 냉방시스템의 냉방 성능특성을 고찰하는 것이다. 특히 자동차의 실도로 운전 조건을 모사할 수 있도록 실험 조건을 선정하였으며 실제 자동차에 적용된 이산화탄소용 냉방시스템에 대하여 다양한 냉방성능 실험을 진행하였다. 결과적으로, 가스쿨러 입구 공기온도가 증가할수록 냉방용량과 COP는 감소하였고 증발기 입구 공기온도가 증가할수록 냉방용량과 COP는 증가하였다. 또한, 압축기 회전속도가 900 rev/min에서 1800 rev/min으로 증가할수록 냉방용량은 42.2% 증가였으나 냉방 COP는 55.4% 감소하였다.

• 한국경영과학회지
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• 제15권1호
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• pp.99-115
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• 1990

This paper is concerned with the unit commitment problem in an electric power system with both thermal and pumped-storage hydroelectric units. This is a mixed integer programming problem and the Lagrangean relaxation method is used. We show that the relaxed problem decomposes into two kinds of subproblems : a shortest-path problem for each thermal unit and a minimum cost flow problem for each pumped-storage hydroelectric unit. A method of obtaining an incumbenet solution from the solution of a relaxed problem is presented. The Lagrangean multipliers are updated using both subgradient and incremental cost. The algorithm is applied to a real Korean power generation system and its computational results are reported and compaired with other works.

• 한국자동차공학회논문집
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• 제24권3호
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• pp.338-344
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• 2016

The study is actively being performed to increase fuel injection pressure of common rail system among countermeasures to meet the emission regulation strengthen of the Diesel engine. The common rail fuel injection tube in such ultra high pressure common rail system has the weakest structural characteristics against vibration that is generated by fuel injection pressure and pulsation during engine operation and driving. Thus the extreme durability is required for common rail fuel injection tube, and the drawing process is being magnified as the most important technical fact for strength of seamless pipe that is the raw material of common rail tube. In this respect, we analyzed the characteristic of dimension and stress variation of the ultra high pressure common rail fuel injection tube by variation of Die and Plug angle in drawing process. Based on the analysis, we tried to obtain the raw material strength of common rail fuel injection tube for applying to the ultra high pressure common rail system. As a result, Plug angle is more important than entry angle of Die and we could obtain the target dimension and strength of the ultra high pressure common rail fuel injection tube through optimization of Plug angle.

• 조명전기설비학회논문지
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• 제28권1호
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• pp.9-15
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• 2014

This paper focuses on the heat gain of a lighting system, one of the most-used appliances in buildings, and its thermal effect within a low energy building. In this study, a dynamic thermal model of a lighting system is first established based on the first principle of thermodynamics. Then, thermal parameters of this model are estimated by experiments and an optimization process. Afterward, the obtained model of the system is validated by comparing simulation results to experimental one. Finally it is integrated into a low energy building model in order to quantify its thermal influence within a low energy building. As a result, heat flux of the lighting system, indoor temperature and heating energy demands of the building are obtained and compared with the results obtained by the conventional model of a lighting system. This paper helps to understand thermal dynamics of a lighting system and to further apply lighting systems for energy management of low energy buildings.

• 마이크로전자및패키징학회지
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• 제22권2호
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• pp.5-9
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• 2015

3차원 적층 반도체에서의 열관리를 위한 연구 동향에 대해서 살펴보았다. 적층 구조는 평면구조와 달리 단위 패키지당 발열량 증가, 단위 바닥면적당 전력 소비량 증가, 이웃 칩의 영향으로 과열 가능성의 증가, 냉각구조 추가의 어려움, 국부 열원의 발달 등으로 발열 문제가 매우 심각해질 수 있으며, 특히 국부 열원은 적층을 위해 칩 두께가 얇아짐으로 더욱 심화되고 있어 이를 고려한 발열관리가 필요하다. 구리 TSV는 높은 열전도도를 이용하여 열원의 열을 효과적으로 주변으로 배출하는 역할을 하며 범프 및 gap 충진 재료, 적층 순서와 함께 적층 반도체의 열확산에 큰 영향을 미친다. 이는 실험으로나 수치해석으로 확인되고 있으며, 향후 적층 구조의 각 구성 요소들의 열 특성을 반영한 회로 설계가 이루어질 것으로 예상된다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.693-697
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• 2007

A control system for solar thermal power plant is the control system to coordinate the whole system's operation, including management of distributed control systems, process control for optimal operation of total system, monitoring system operating conditions and doing administrative functions. This work, as a progress report, presents the results obtained so far in building a control system for the 1MW solar thermal power plant. To make the control system, we first defined the control system's hierarchy and classified the role of each layer. Then, as the first stage of making control system, we designed and developed the sun tracking control system for heliostat.