• 제목, 요약, 키워드: Expected efficiency

검색결과 2,327건 처리시간 0.051초

병렬 시스템에서의 최적 중복부품수와 최적 부하수준 (Optimal Redundant Units and Load in Parallel Systems)

  • 윤원영;김귀래
    • 한국경영과학회지
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    • v.23 no.1
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    • pp.97-107
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    • 1998
  • This paper is concerned with a parallel system that sustains a time-independent load and consists of n components with exponential lifetimes. It is assumed that the total load is shared by the working components and the failures of components increase higher failure rates in the surviving components according to the relationship between the load and the fialure rates. The power rule model among several load-failure rate relationships is considered. We consider the system efficiency meausre as the expected profit earned by the system per unit time. The high load causes high gain but it also occurs frequent system failures. The expected profit per unit time is used as criterion to evaluate the system efficiency. The goal of system engineer is to determine the optimal load and redundant units maximizing the expected profit per unit time. First, the system reliability function is obtained and the optimization problem of the load-sharing parallel system is considered. Given the redundant units, the existence of the optimal load can be proved analytically and given the load, the optimal redundant units can be solved also analytically. The optimal load and redundant units are obtained simultaneously by numerical computation. Some numerical examples are studied.

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PV-BESS 시스템의 적정 PCS, 배터리용량 산정에 따른 최적 운영에 관한 연구 (A Study on the Optimal Operation According to Appropriate PCS and Battery Capacity Estimation of PV-BESS System)

  • 최윤석;나승유
    • 전기학회논문지
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    • v.67 no.9
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    • pp.1174-1180
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    • 2018
  • In December 2017, the government announced plans to increase the current proportion of renewable energy from 7% to 20% by 2030 through a plan called the Renewable Energy 3020 Implementation Plan. Therefore, the demand for installation of photovoltaic(PV), wind turbine(WT) and battery energy storage system(BESS) is expected to increase. In particular, the system combined with energy storage system(ESS) is expected to take up a large portion since PV and WT can receive high renewable energy certificates(REC) weights when combined with ESS. In this study, we calculate the optimal capacity of the power conditioning system(PCS) and the BESS by comparing the economical efficiency and maximize the efficiency of the PV-BESS system in which the PV and the BESS are connected. By analyzing the system marginal price(SMP) and REC, it maximize profits through application of REC weight 5.0 and optimal charge-discharge scheduling according to the SMP changes.

AFPM, RFPM 복합발전기의 모델링 및 해석 (Modelling and Analysis of AFPM, RFPM Compound Generator)

  • 김진사
    • 한국전기전자재료학회논문지
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    • v.30 no.7
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    • pp.459-462
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    • 2017
  • In this study, we design, model, and analyze a compound generator that combines the axial flux permanent magnet (AFPM,) and radial flux permanent magnet (RFPM), which is expected to increase power generation by allowing the magnets to be placed on the upper, lower, left, and right sides of the same-sized generator. Through the design, modelling, and analysis of AFPM and RFPM compound generators, the generator load evaluation results rated output of 500.25 W and efficiency of 87.60%, respectively, at a rated speed of 600 rpm. By employing this complex generation system,these findings are expected to contribute to the activation of a small power generation system.

EFFICIENCY MEASUREMENT AND ENERGY ANALYSIS FOR A HEV BENCH TESTER AND DEVELOPMENT OF PERFORMANCE SIMULATOR

  • OH K.;KIM D.;KIM T.;KIM C.;KIM H.
    • International Journal of Automotive Technology
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    • v.6 no.5
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    • pp.537-544
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    • 2005
  • This paper presents the efficiency measurement and energy analysis for a parallel HEY. Using the HEV test rig, the efficiency of each powertrain component is measured for a given driving cycle including the regenerative braking system. Accompanied by the efficiency measurements, a detailed energy analysis is performed. Based on the efficiency measurement and energy analysis, a HEV performance simulator is developed. Using the simulator, the HEV performance is evaluated for a mild hybrid system. It is expected that the HEV simulator developed can be used to obtain further optimization potentials.

계자권선 절환에 의한 직류전동기의 고효율 추종 운전 (High Efficiency Tracking Drive in DC Motor by Field Winding Switching Method)

  • 윤기정;김광헌
    • 대한전기학회:학술대회논문집
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    • pp.493-496
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    • 1997
  • This paper constructed the experimental system which is able to drive in series or separately excited by switching of the field winding, using a DC motor and obtained the characteristics of efficiency with speed and torque of each motor's type through the experiment. From this result controlled drive which is able to series DCM or separately excited DCM in the optimal point of efficiency as finding the types of motor having maximum efficiency with torque and speed. By performing high efficiency tracking drive, it is expected that energy consumption of power source with limited energy density would be reduced, and so utility efficiency would be improved.

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하수처리수 재이용을 위한 실규모 입상황 생물막여과 시설의 효율증대 방안에 관한 연구 (A Study by Proposal of Efficiency Increase for a Full-scale Wastewater Reclamation Facility using a Biofilter Packed with Granular Sulfur)

  • 문진영;황용우;백승륜
    • 상하수도학회지
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    • v.24 no.1
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    • pp.73-83
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    • 2010
  • This study was performed to increase the removal efficiency of the biofilter packed with granular sulfur in municipal wastewater reclamation facility. Constituent units were influent water tank, denitrification tank, BOD reduction tank and outlet. And, the major operation factor is a biofilter packed with submerged granular sulfur. Actual wastewater and synthetic wastewater were used as influent wastewater. Experimental condition was divided into two phases according to the amount of a phosphorus coagulant. Total phosphorus removal efficiency was insignificant at mode I that phosphorus coagulant was not injected. The average influent and effluent total phosphorus concentrations at mode II were 0.5 ~ 1.0 mg/L and 0.27 mg/L, respectively. As for COD and BOD effluent concentrations, COD was 3.0 mg/L and BOD was 1.0 mg/L. Additionally, nitrogen removal rates were high at low influent DO concentration. In conclusion, a new process, biofilter packed with granular sulfur is expected to treat high-rate nitrogen wastewater and expected to be utilized as an alternative of technological innovation for the nitrogen treatment.

클라우드 컴퓨팅 서비스 도입 시 기대효과 요인의 중요도 우선순위 도출에 관한 연구 (A Study on the Importance Priority of Expected Effect Factors in the Introduction of Cloud Computing Service)

  • 강다연;김상현
    • 한국콘텐츠학회논문지
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    • v.20 no.4
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    • pp.564-570
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    • 2020
  • 클라우드 컴퓨팅 서비스 기술의 발달은 기업에서 특히나 중요한 역할을 차지하고 있다. 기업의 클라우드 컴퓨팅 서비스 도입이 시장가치와 기업의 수익률 변화의 향상에도 기여하고 있는 실정이다. 본 연구에서는 클라우드 컴퓨팅 서비스 도입 시 기대할 수 있는 특성요인들을 효율성, 경제성, 종속성이라는 특성으로 구분하여 평가할 수 있는 하위 항목들을 선정하여 우선순위 중요도를 실증분석 하였다. 주요우선순위 항목은 선행연구를 기반으로 선정하였으며, IT시스템 전문가들을 대상으로 설문을 실시하였다. AHP 분석기법을 활용하여 쌍대비교를 수행한 결과 최종 우선순위를 도출하였으며, 본 연구결과는 추후 기업의 클라우드 컴퓨팅 서비스 수용 의사결정을 판단하는 중요한 자료로 활용될 것이다.

기회비용을 고려한 열화시스템의 보전한계갱신정책 (Maintenance Limit Renewal Policy for Inferiority System based on Opportunity Cost)

  • 박상민;김연수
    • 산업경영시스템학회지
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    • v.17 no.32
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    • pp.233-242
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    • 1994
  • This study deals with the derivative adverse minimum for inferiority system depends on continuose operating under infinite planning horizon. This planning will be accomplished by maintenance limit renewal policy in consideration of opportunity cost which affects system by failure during operation periods and expected cost under nomal operation states. By the results, we will be expected incresing total efficiency for the system by optimal renewal policy.

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원자력 이용 고체산화물 고온전기분해 수소 및 합성가스 생산시스템의 열역학적 효율 분석 연구 (A Study on Thermodynamic Efficiency for HTSE Hydrogen and Synthesis Gas Production System using Nuclear Plant)

  • 윤덕주;고재화
    • 한국수소및신에너지학회논문집
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    • v.20 no.5
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    • pp.416-423
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    • 2009
  • High-temperature steam electrolysis (HTSE) using solid oxide cell is a challenging method for highly efficient large-scale hydrogen production as a reversible process of solid oxide fuel cell (SOFC). The overall efficiency of the HTSE hydrogen and synthesis gas production system was analyzed thermo-electrochemically. A thermo-electrochemical model for the hydrogen and synthesis gas production system with solid oxide electrolysis cell (SOEC) and very high temperature gas-cooled reactor (VHTR) was established. Sensitivity analyses with regard to the system were performed to investigate the quantitative effects of key parameters on the overall efficiency of the production system. The overall efficiency with SOEC and VHTR was expected to reach a maximum of 58% for the hydrogen production system and to 62% for synthesis gas production system by improving electrical efficiency, steam utilization rate, waste heat recovery rate, electrolysis efficiency, and thermal efficiency. Therefore, overall efficiency of the synthesis production system has higher efficiency than that of the hydrogen production system.

염료감응형 태양전지와 열전발전소자를 결합한 복합 태양전지의 구조 및 특성 (Structure and Characteristics of Tandem Solar Cell Composed of Dye-sensitized Solar Cell and Thermoelectric Generator)

  • 이동윤;송재성;이원재;김인성;정순종
    • 한국전기전자재료학회논문지
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    • v.18 no.4
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    • pp.357-362
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    • 2005
  • The tandem solar cell composed of a dye-sensitized solar cell (DSC) and a thermoelectric generator (TEG) was designed. In such new cell, the characteristics of DSC and TEG were investigated. DSC uses the wavelength range of 380∼750 nm and has the maximum efficiency of below 10 %. If the solar light transmitted through DSC can be converted to heat energy, TEG can generate electric energy using this heat energy. By this means, it is possible to utilize most of solar energy in the wavelength range of 350∼3000 nm for electric generation and it can be expected to obtain higher solar energy conversion efficiency exceeding the known limit of maximum efficiency. For this purpose we suggest the tandem solar cell constructed with DSC and TEG. In this structure, DSC has a carbon nanotube film as a counter electrode of DSC in order to collect the solar light and convert it to heat energy. We measured the I-V characteristics of DSC and TEG, assembled to the tandem cell. As a result, it was shown that DSC with carbon nanotube and TEG had the efficiency of 9.1 % and 6.2 %, respectively. From this results, it is expected that the tandem solar cell of the new design has the possibility of enhanced conversion efficiency to exceed above 15 %.