• 전기학회논문지P
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• 제64권2호
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• pp.74-78
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• 2015

With the improvement of living standards and economic development, electricity consumption continues to grow. The electricity is a special energy which is hard to store, so its supply must be consistent with the demand. The objective of electricity demand forecasting is to make best use of electricity energy and provide balance between supply and demand. Hence, it is very important work to forecast electricity demand with higher precision. So, various forecasting methods have been developed. They can be divided into five broad categories such as time series models, regression based model, artificial intelligence techniques and fuzzy logic method without considering special-day effects. Electricity demand patterns on holidays can be often idiosyncratic and cause significant forecasting errors. Such effects are known as special-day effects and are recognized as an important issue in determining electricity demand data. In this research, we developed the power demand forecasting method using ELM(Extreme Learning Machine) for special day, particularly, lunar new year and Chuseok holiday.

• Structural Engineering and Mechanics
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• 제10권4호
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• pp.405-426
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• 2000

Two approximate methods based on mechanism analysis suitable for seismic assessment/design of structural concrete are reviewed. The methods involve use of equal energy concept or equal displacement concept along with appropriate patterns of inelastic deformations to relate structure's maximum lateral displacement to member and plastic deformations. One of these methods (Clough's method), defined here as a ductility-based approach, is examined in detail and a modification for its improvement is suggested. The modification is based on estimation of maximum inelastic displacement using inelastic design response spectra (IDRS) as an alternative to using equal energy concept. The IDRS for demand displacement ductilities are developed for a single degree of freedom model subjected to several accelerograms as functions of response modification factor (R), damping ratios, and strain hardening. The suggested revised methodology involves estimation of R as the ratio of elastic strength demand to code level demand, and determination of design base shear using $R_{design}{\leq}R$ and maximum displacement, determination of plastic displacement using IDRS and subsequent local plastic deformations. The methodology is demonstrated for the case of a 10-story precast wall panel building.

• Plant Breeding and Biotechnology
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• 제6권4호
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• pp.363-380
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• 2018

Wheat is frequently exposed to high temperature during anthesis and ripening period, which resulted in yield loss and detrimental end-use-quality. The transcriptome analysis of wheat under high temperature stress during the early stage of the grain filling period was undertaken. Three expression patterns of differentially expressed genes (DEGs) during grain filling period were identified. The DEGs of seed storage protein and starch-branching enzyme showed continuous increases in their expressions during high temperature stress, as well as during the recovery period. The activities of the enzymes responsible for the elimination of antioxidants were significantly affected by exposure to high temperature stress. Only the WAS-2 family genes showed increased transcription levels under high temperature stress in dehulled spikelets. The relative transcription levels for sub-genome specific WAS-2 genes suggested that WAS-2 genes reacted with over-expression under high temperature stress and decreased back to normal expression during recovery. We propose the role of WAS-2 as a protective mechanism during the stage of grain development under high temperature in spikelets.

• Tribology and Lubricants
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• 제23권6호
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• pp.283-287
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• 2007

Permanent-magnet (PM) passive bearings use the repulsive forces between the rotor and the stator magnets for the bearing function. It is desirable that the stiffness of the bearing is maximized with the given volume of the magnet. The stiffness is affected by the magnet strength, the number of layers, and the magnetization patterns. Previously, finite-element method (FEM) has been used to maximize the stiffness of the bearing. In this paper, we used the equivalent current sheet method to calculate the stiffness. The validity of this approach is checked against FEM results. The optimized bearing is applied to a micro flywheel energy storage system.

• Journal of Information Processing Systems
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• 제13권2호
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• pp.285-304
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• 2017

Big data information and pattern analysis have applications in many industrial sectors. To reduce energy consumption effectively, the eco-driving method that reduces the fuel consumption of vehicles has recently come under scrutiny. Using big data on commercial vehicles obtained from digital tachographs (DTGs), it is possible not only to aid traffic safety but also improve eco-driving. In this study, we estimate fuel consumption efficiency by processing and analyzing DTG big data for commercial vehicles using parallel processing with the MapReduce mechanism. Compared to the conventional measurement of fuel consumption using the On-Board Diagnostics II (OBD-II) device, in this paper, we use actual DTG data and OBD-II fuel consumption data to identify meaningful relationships to calculate fuel efficiency rates. Based on the driving pattern extracted from DTG data, estimating fuel consumption is possible by analyzing driving patterns obtained only from DTG big data.

• 한국전기전자재료학회논문지
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• 제31권2호
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• pp.94-97
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• 2018

Lead zirconate titanate/poly-vinylidene fluoride (PZT/PVDF) piezoelectric devices were fabricated by incorporating carbon nanotubes (CNTs), for use as flexible energy harvesting devices. CNTs were added to maximize the formation of the ${\beta}$ phase of PVDF to enhance the piezoelectricity of the devices. The phase transition of PVDF induced by the addition of CNTs was confirmed by analyzing the X-ray diffraction patterns, scanning electron microscopy images, and atomic force microscopy images. The enhanced output efficiency of the PZT/PVDF piezoelectric devices was confirmed by measuring the output current and voltage of the fabricated devices. The maximum output current and voltage of the PZT/PVDF piezoelectric devices was 200 nA and 350 mV, respectively, upon incorporation of 0.06 wt% CNTs.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.105-108
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• 2007

Fuel cell with high electric efficiency has many probabilities of commercial use. Especially, proton exchange membrane fuel cell (PEMFC) which is a low temperature fuel cell and has less influence on $CO_2$ concentration is considered the power generation system of small building and household. We calculated the optimal operational plans of 1 kW household PEMFC power system based on the daily electricity and heat demand patterns of Japan and Korea. Calculated results show that the economic feasibility of PEMFC power system is very sensitive to the cost policy of electricity and natural gas.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.722-724
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• 2004

Demand estimates in electric power systems have traditionally consisted of time-series analyses over long time periods. The resulting database consisted of huge amounts of data that were then analyzed to create the various coefficients used to forecast power demand. In this research, we take advantage of universally used analysis techniques analysis, but we also use easily available data-mining techniques to analyze patterns of days and special days(holidays, etc.). We then present a new method for estimating and forecasting power flow using decision tree analysis. And because analyzing the relationship between the estimate and power system ceiling Trices currently set by the Korea Power Exchange. We included power system ceiling prices in our estimate coefficients and estimate method.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.31-34
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• 2007

Fuel cell with high electric efficiency has many probabilities of commercial use. Especially, polymer electrolyte or proton exchange membrane fuel cell (PEMFC) which is a low operating temperature and has less influence on $CO_2$ concentration is considered the power generation system of small building and household. We calculated the optimal operational plans of 1 kW household PEMFC power system based on daily electric and heat demand patterns of various size of apartments. Calculated results show that the economic feasibility of PEMFC power system is very sensitive to the cost policy of electricity and natural gas.

• 물과 미래
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• 제16권1호
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• pp.41-48
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• 1983

세계 식량 및 에너지 위기의 심화에 따른 여러 가지 용수공급의 경합에 맞추어, 시스템공학의 지역적 수자원 개발 계획에 대한 적용이 중요시되고 있다. 도시 수자원과 토지 이용 전략 및 이에 따른 환경 영향에 관한 논의와 함께, 분배 관망의 최소 비용안을 구하기 위한 선형계획 및 비선형계획 방법을 제시하였다. 또한 주어진 가상용수 수요에 대비한 부배 모형의 작성 및 실제전산 처리를 통하여 장래 용수 공급원에 관한 민감도를 분석하였다.