• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2005년도 한국컴퓨터종합학술대회 논문집 Vol.32 No.1 (A)
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• pp.853-855
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• 2005

본 논문은 Sequence Diagram을 이용한 안전등급 PLC(Safety-Grade Programmable Logic Controller) 운영 체제의 인터페이스 설계명세를 기술한다. 원자력 발전소에 사용하기 위한 안전 소프트웨어(Safety Software)의 규제 기준인 Reg. Guide는 IEEE Std 1016, IEEE Std 1016.1 의 설계명세서 작성 표준에 따라 작성하도록 요구하며, 이러한 규제기준과 기 표준을 안전등급 PLC를 위한 운영체제 소프트웨어의 설계명 세서도 만족해야 한다. 특히 운영 체제와 외부 장치들 사이의 인터페이스를 위해 실시간 특성의 표현에 장점을 갖는 Sequence Diagram을 적용함으로써 운영체제의 인터페이스에 대한 정확성, 완전성, 그리고 일관성을 향상시킬 수 있었다.

• 한국강구조학회 논문집
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• 제13권2호
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• pp.163-176
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• 2001

본 논문에서는 뒴비틀림 효과를 고려한 휨비틀림 이론을 기초로 연속곡선보를 해석한다. 먼저 단순곡선보에 대해 미분방정식으로 단면력과 변위를 구한다. 다음 에너지법을 이용하여 n경간 연속곡선보에 대한 탄성방정식으로 연속곡선보의 임의점에서 단면력과 변위의 해를 구한다. 작용하중으로 수직집중하중과 수직등분포하중을 고려하여 해석하였으므로 실제 하중이 작용하는 연속곡선박스거더의 단면력과 변위를 쉽게 구할 수 있다.

• 중소기업융합학회논문지
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• 제2권2호
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• pp.13-19
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• 2012

임베디드 시스템의 발전으로 인해 다양한 품질 속성에 대한 요구사항들이 증가하고 있다. 배터리를 사용하는 모바일 임베디드 시스템의 경우 제한된 전력공급으로 인해 시스템의 전력소모를 절감하기 위한 노력이 요구된다. 특히 임베디드 시스템에 탑재되는 소프트웨어들이 점차 복잡해지고 다양한 기능을 수행함에 따라 소프트웨어에 대한 소모전력 절감 연구들이 관심 받고 있다. 또한 최근에는 모델 기반 소모전력 분석을 통해 소프트웨어 개발 초기 단계에서 소모전력 요구사항을 반영하기 위한 연구들도 진행되고 있다. 따라서 본 논문에서는 SysML(Systems Modeling Language)의 Parametric 다이어그램을 이용한 모델 기반 소모전력 분석 기법을 제안한다. 제안하는 기법은 Parametric 다이어그램의 특성을 이용하여, 실제 전력소모를 유발하는 소프트웨어의 행위에 대한 모델을 작성한다. 이를 기반으로 소프트웨어의 실행으로 인한 소모전력 값을 도출할 수 있으며, 같은 기능을 갖는 모듈들에 대한 소모전력 품질속성을 비교할 수 있다는 장점이 있다.

• 한국시스템다이내믹스연구
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• 제11권3호
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• pp.61-86
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• 2010

This research analyzed on the future energy society of Korea in 2030 using system thinking approach. Key uncertainty factors determining the future energy society were analyzed in a multi disciplinary view point such as politics, economy, society, ecology and technology. Three causal loop diagrams for the future energy system in Korea and related policy leverages were shown as well. 'Global economic trends', 'change of industrial structure' and 'energy price' were identified as key uncertainty factors determining the Korean energy future. Three causal loop diagrams named as 'rate of energy self－sufficiency and alternative energy production', 'economic activity and energy demand' and 'Excavation of new growth engines' were developed. We integrated those causal loop diagrams into one to understand the entire energy system of the future, proposed three strategic scenarios(optimistic, pessimistic and most likely) and discussed implications and limits of this research.

• Journal of Electrochemical Science and Technology
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• 제9권1호
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• pp.51-59
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• 2018

Various Si-Fe-Al ternary alloys were prepared with the same amount of Si by the melt spinning technique. The feasibility of the capacity prediction approach based on the estimation of the active amount of Si using the phase diagram was practically examined and reported. These predictions were verified by the electrochemical test of fabricated coin cells and other characterization methods. The capacity prediction approach using the phase diagram might be a fundamental and efficient method to accelerate the practical application of Si-based alloys as the anode material for Li-ion batteries. The details on the prediction procedure were discussed.

• Journal of Advanced Marine Engineering and Technology
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• 제23권6호
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• pp.770-777
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• 1999

In this study a phase diagram has been used to investigate the unsteadiness of two-dimensional lid-driven closed flows within a square cavity for twelve Reynolds numbers; $7.5{\times}10^3,\; 8{\times}10^3,\; 8.5{\times}10^3,\; 9{\times}10^3,\; 9.5{\times}10^3,\; 10^4,\;1.5{\times}10^4,\;2{\times}10^4,\; 3{\times}10^4,\; 7.5{\times}10^4$ and $10^5$. The results indicate that the first critical Reynolds number at which the flow unsteadiness of sinusoidal fluctuation appears from the temporal variation of total kinetic energy curves is assumed of sinusoidal fluctuation appears form the temporal variation of total kinetic energy curves is assumed to be in the neigh-bourhood of $Re=8.5{\times}10^3$ The second critical Reynolds number where the periodic amplitude and frequency collapse to random disturbance being existed around $Re=1.5{\times}10^4$ The exponentially decreasing vortices formed at the lower two corners are found commonly at the time-mean flow pattern of $Re=3{\times}10^4$.

• 한국태양에너지학회 논문집
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• 제36권2호
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• pp.19-29
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• 2016

Whilst there are growing interests in pursuing energy efficiency and zero-energy buildings in built environment, it is widely recognised that Building-Integrated Photovoltaic (BIPV) is one of the most promising and required technologies to achieve these goals in recent years. Although BIPV is a broadly utilized technique in variety of fields in built environments, it is required that generation of BIVP should be analysed and calculated by external specialists. The aim of this research is to focus on developing a new diagram for prediction of the pre-estimation model in early design stage to harness solar radiation data, PV types, slopes, azimuth and so forth. The results of this study show as follows: 1) We analysed 162 districts in a national level and the examined areas were categorised into five zones. The standard deviation of the results was 2.9 per cent; 2) The increased value of solar radiation on a vertical plane in five categorised zones was 42kWh/m3, and the result was similar to the average value of 43.8kWh/m3; and 3) The pre-estimation of diagram was developed based on the categorisation of zones and azimuth as well as the results of the developed diagram showed little difference compared to the previously utilised method. The suggested diagram in this paper will contribute to estimate BIPV without any external contribution to calculate the value. Even though the result of this study shows little difference, it is required to investigate a number of different variables such as BIPV types, modules, slope angle and so forth in order to develop an integrated pre-estimation diagram.

• Journal of Power Electronics
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• 제9권4호
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• pp.553-566
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• 2009

In-phase control and energy-optimized control are the two major control strategies proposed for series power quality controllers (SPQC). However quantitative analysis and comparison between these two control strategies is quite limited in previous publications. In this paper, an extensive quantitative analysis is carried out on these two control strategies through phasor diagram approach, and a detailed quantitative comparison is conducted accordingly. The load current is used as the reference phasor, and this leads to a simpler and clearer phasor diagram for the quantitative relationship. Subsequently detailed analysis of SPQC using in-phase control and energy-optimized control are provided respectively, under different modes both for under voltage/voltage sag and for over voltage/voltage swell. The closed form analytic expressions and the curves describing SPQC compensation characteristics are obtained. The detailed system power flow is figured out for each mode, and the detailed quantitative comparison between the two control strategies is then carried out. The comparison covers several aspects of SPQC, such as required compensating voltage magnitude, required capacity of energy storage component, and maximal ride-through time. In the end, computer simulation and prototype experimental results are shown to verify the validity of all the analysis and the result of the comparison.

• International Journal of Fluid Machinery and Systems
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• 제8권3호
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• pp.169-182
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• 2015

When simulating the dynamic behaviour of a hydro power plant, it is essential to have a good representation of the turbine behaviour. The pressure transients in the system occurs because the flow changes, which the turbine defines. The flow through the turbine is a function of the pressure, the speed of rotation and the wicket gate opening and is, most often described in a performance diagram or Hill diagram. In the Hill diagram, the efficiency is drawn like contour lines, hence the name. A turbines Hill diagram is obtained by performance tests on scaled model in a laboratory. However, system dynamic simulations have to be performed in the early stage of a project, before the turbine manufacturer has been chosen and the Hill diagram is known. Therefore one have to rely on diagrams for a turbine with similar speed number. The Hill diagram is drawn through measured points, so for using the diagram in a simulation program, one have to iterate in the diagram based on curve fitting of the measured points. This paper describes an alternative method. By means of the Euler turbine equation, it is possible to set up two differential equations which represents the turbine performance with good enough accuracy for the dynamic simulations. The only input is the turbine's main geometry, the runner blade in- and outlet angle and the guide vane angle at best efficiency point of operation (BEP). In the paper, simulated turbine characteristics for a high head Francis turbine, and for a reversible pump turbine are compared with laboratory measured characteristics.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2018년도 추계학술논문요약집
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• pp.488-489
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• 2018