• Title/Summary/Keyword: Improvement of efficiency

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Asymptotic Relative Efficiency for New Scores in the Generalized F Distribution

  • Choi, Young-Hun
    • Communications for Statistical Applications and Methods
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    • v.11 no.3
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    • pp.435-446
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    • 2004
  • In this paper we introduced a new score generating function for the rank dispersion function in a multiple linear model. Based on the new score function, we derived the asymptotic relative efficiency, ARE(11, rs), of our score function with respect to the Wilcoxon scores for the generalized F distributions which show very flexible distributions with a variety of shape and tail behaviors. We thoroughly explored the selection of r and s of our new score function that provides improvement over the Wilcoxon scores.

A Study on the Turbine Performance in the steam seal variable clearance packing type of Steam turbine (증기터빈의 가변패킹 형태에 따른 터빈성능 평가에 관한 연구)

  • Kweon, Y.S.;Suh, J.S.
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1676-1681
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    • 2004
  • The main reason for applying positive pressure variable clearance packing in fossil power plant is high efficiency and energy saving movement in the government. This study intends to analyze the turbine efficiency through the shaft packing improvement in thermal power plant and makes its comparison to that of the each packing type

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Rank Scores for Linear Models under Asymmetric Distributions

  • Choi, Young-Hun
    • Communications for Statistical Applications and Methods
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    • v.13 no.2
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    • pp.359-368
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    • 2006
  • In this paper we derived the asymptotic relative efficiency, ARE(ms, rs), of our new score function with respect to the McKean and Sievers scores for the asymmetric error distributions which often occur in practice. We thoroughly explored the asymptotic relative efficiency, ARE(ms, rs), of our score function that provides much improvement over the McKean and Sievers scores for all values of r and s under asymmetric distributions.

Improvement of the $SO_{x}$ Removal by Adding Dibasic Acids into the JBR FGD Process

  • Lee, Byeong-Kyu;Jeon, Sang-Ki;Cho, Seong-Won
    • Journal of Korean Society for Atmospheric Environment
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    • v.17 no.E4
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    • pp.157-162
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    • 2001
  • Jet Bubbling Reactors(JBRs) were operated for the removal of SO$_{x}$ in flue gases produced from many electric power plants. However, many JBR flue gas desulfurization (FGD) facility faced a decrease of SO$_{x}$ removal efficiency and an increase of scale problems with continuous operations. We increased alkalinity of the SO$_{2}$ absorbing medium by adding the dibasic acids (DBAs) to solve these problems more effectively. The SO$_{2}$ removal efficiency, the purity of CaCO$_{3}$ and COD of the wastewater was measured to identify the addition effects of DBAs (150, 200, 250, and 400 ppm) for 2hr in a day into the JBR attached to the large-scale power plants (400 MW$\times$3). Addition of the DBAs resulted in the improvement of the SO$_{2}$ removal efficiency from 2 to 5% and the purity of the gypsum from 1 to 2%; these improvement were due to the alkalinity increase of the absorbing medium and the reduction of a proportion of un-reacted CaCO$_{3}$, respectively. Also, the scale problems formed by un-reacted CaCO$_{3}$ inside the reaction zone of the JBR were substantially reduced. Even though the effluent COD of the wastewater slightly increased from 10~15 to 18~36 mg/l and the erosion problems in the injection pump and duct occurred, this method of increasing SO$_{2}$ removal efficiency by adding the DBAs could be considered as a profitable approach.ach.

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Current Status for Generation, Treatment and Recycling of Waste Resources in the Domestic Industry and Improvement Measures of Resource Efficiency (국내(國內) 산업(産業) 폐자원(廢資源)의 발생(發生)·처리(處理)·재자원화(再資源化) 현황(現況) 및 자원효율성(資源效率性) 향상(向上) 방안(方案))

  • Kang, Hong-Yoon;Lee, Il-Seuk;Kim, Kyung-Hwan
    • Resources Recycling
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    • v.22 no.3
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    • pp.3-17
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    • 2013
  • Recently, the importance of efficient resource management has been highlighted due to the uncertainty of its security. Korea has thus made an effort to improve the resource productivity in various fields such as the increase of recycling rate and the establishment of methodical resource management system. It is still necessary to draw the innovative improvement measure of national resource efficiency. This study derives major issues of recycling potential in the domestic industry by analyzing the current status of generation, treatment and recycling of industrial wastes in Korea. Futhermore, main tasks for promoting the improvement of national resource efficiency through the recycling of industrial wastes in Korea have been proposed based on the results of this study with the comparison of Japan's situation.

Development of geothermal exchanger for efficiency improvement of solar cell module (태양전지 모듈의 효율개선을 위한 지열교환 장치 개발)

  • Lee, Jei-Hoon;Oh, Hun;Kim, Jun-Seong;Kim, Do-Woong;Park, Wal-Seo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.4
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    • pp.2966-2970
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    • 2015
  • Recently, solar light power generation is widely extended by support policy to regeneration energy. However generation efficiency is decreased when solar module maintain higher than certain point temperature. Therefore, it is need to maintenance under certain point temperature. An method of solving this problem, this paper is developed geothermal exchanger for efficiency improvement of solar cell module. Geothermal exchanger consisted of heat absorber of solar cell module and heat conductor and radiator. Heat of solar cell module is radiated in the earth by geothermal exchanger. An a result, geothermal exchanger is increased generation amount of solar cell module and experiment result showed costs to about 36% increment of generation power.

Efficiency Improvement of $N^+NPP^+$ Si Solar Cell with High Low Junction Emitter Structure (고저 접합 에미터 구조를 갖는 $N^+NPP^+$ Si 태양전지의 효율 개선)

  • 장지근;김봉렬
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.21 no.1
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    • pp.62-70
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    • 1984
  • N+NPP+ HLEBSF (high low emitter back surface field) solar cells which have N+N high low junction in the emitter as well as N+PP+ BSF cells were designed and fabricated by using <111> oriented P type Si wafers with the resistivity of 10$\Omega$/$\textrm{cm}^2$ and the thickness of 13-15 mil. Physical parameters (impurity concentration, thickness) at each region of N+PP+ and N+NPP+ cell were made equally through same masks and simultaneous process except N region of HLEBSF cell to investigate the high low emitter junction effect for efficiency improvement. Under the light intensity of 100 mW/$\textrm{cm}^2$, total area (active area) conversion efficiency were typically 10.94% (12.16%) for N+PP+ BSF cells and 12.07% (13.41%) for N+N PP+ cells. Efficiency improvement of N+NPP+ cell which has high low emitter Junction structure is resulted from the suppression of emitter recombination current and the increasement of open circuit voltage (Voc) and short circuit current (Ish) by removing heavy doping effects occurring in N+ emitter region.

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