• Title, Summary, Keyword: efficiency

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A Study on the Evaluation of Efficiency in the Korean Small and Medium sized Construction Firms (국내 중소건설업체의 효율성 평가에 관한 연구)

  • Kim, Hyuk;Yoo, Han-Joo;Song, Gwang-Suk
    • Journal of the Korean Society for Quality Management
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    • v.38 no.3
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    • pp.463-474
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    • 2010
  • In this study, we evaluate the efficiency of Construction Industry using Data Envelopment Analysis(DEA). Since the Construction Industry has been traditionally operated through competition, it is important to measure the efficiency. In this paper, we empirically analyze the Efficiency of the 50 Korean Construction Industry. In detail, we used the scale of efficiency in order that efficiency cannot be affected by the total technical efficiency of each company and the scale of DMU by applying CCR or BBC model. Also, we analyzed the changes of measurement DEA model score. we adopted the basic DEA, RTS Region and MPSS(Most Productive Scale Size) method which are combined with efficiency measurement model in order to analyze the operational status. Furthermore, by complementing the shortfalls of the scale efficiency value of the DEA Model, RTS Region Model can be recommended to be appropriate in the evaluation of ideal input/output Quantity. In particular, input variables are total assets, construction capacity, the technical staff and output variables are sales volume, operating income. The result of RTS Region and MPSS shows that 9 DMUs of the efficiency frontier in the Construction Industry are analyzed to be relatively efficient DMUs, and 41 DMUs are analyzed to be inefficient DMUs, and finally inefficient DMUs are separated with Region 1 and Region 6.

Emission Characteristics of White Organic Light-Emitting Diodes Using Micro Lens Array Film (Micro Lens Array Film을 이용한 백색 OLED의 발광 특성)

  • Chun, Hyun-Dong;Na, Hyunseok;Yang, Jae-Woong;Ju, Sung-Hoo
    • Journal of the Korean institute of surface engineering
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    • v.46 no.2
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    • pp.93-97
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    • 2013
  • We studied the emission characteristics of white phosphorescent organic light-emitting diodes (PHOLEDs), which were fabricated using a two-wavelength method. To optimize emission characteristics of white PHOLEDs, white PHOLEDs with co-doping and blue/co-doping emitting layer (EML) structures were fabricated using a host-dopant system. The total thickness of light-emitting layer was 25 nm and the dopant of blue and red was FIrpic and $Bt_2Ir(acac)$ in UGH3, respectively. In case of co-doping structure, applying micro lens array film showed efficiency improvement from the current efficiency 78.5 cd/A and power efficiency 40.4 lm/W to the current efficiency 131.1 cd/A and power efficiency 65 lm/W and blue / co-doping structure showed efficiency improvement from the current efficiency 43.8 cd/A and power efficiency 22 lm/W to the current efficiency 69 cd/A and power efficiency 32 lm/W.

Regional Financial Development, Firm Heterogeneity and Investment Efficiency

  • Zhang, Ruonan;Yin, Hong
    • The Journal of Asian Finance, Economics, and Business
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    • v.5 no.4
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    • pp.73-83
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    • 2018
  • The purpose of this paper is to examine the relationship between regional financial development and corporate investment efficiency as well as the relationship between firm-level characteristics and corporate investment efficiency. Using a large sample of A-listed companies in China from CSMAR database between 2003 and 2016, this paper explores corporate investment efficiency and its influencing factors in emerging market on the basis of heterogeneous stochastic frontier model. The results show that: (1) the average investment efficiency of Chinese listed companies is 74.5%, and the investment efficiency of large enterprises, state-owned enterprises and enterprises with relatively high financial development level is significantly higher; (2) compared with average corporate investment efficiency in the year 2003, the investment efficiency of different types of enterprises in 2016 is significantly higher, and the gap is gradually widening; (3) enterprise heterogeneity namely firm size, nature of property right, and institutional environment reflected by the level of regional financial development indirectly affects corporate investment efficiency by influencing the financing constraints and uncertainty. The findings suggest that to improve corporate investment efficiency in emerging market, financial market should be accelerated, regional balance should be restored and the differences among regions, industries and differences between public and private sectors should be eliminated.

DEA를 이용한 통신 사업자의 효율성 측정에 관한 연구

  • 김찬규;김현종
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • pp.213-217
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    • 2001
  • This paper deals with the estimation of efficiency of Telecommunication Operators(TOs) using DEA (Data Envelopment Analysis). The measure of efficiency using DEA accomplishes next two steps. First, the efficient frontier is derived using the data of input and output. And then the efficiency of the decision making units are measured by the distances from this frontier To measure efficiency, we consider a one-output, three-input production function. We use the tangible assets, investment cost, the number of employees for input data and measure the output by the revenue. After measuring the efficiency, We can compare the domestic TOs with the international TOs and the wire TOs with wireless ones by average efficiency. After accomplishing the analysis of efficiency, the internal/external efficiency is measured simultaneously through correlation between efficiency and profitability, quality level.

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An Experimental Study on the Efficiency of the Water Hydraulic Piston Pump System driven by an Electric Inverter (전기 인버터 구동 수압 피스톤 펌프 시스템의 효율 성능에 관한 실험적 연구)

  • Ham, Y.B.;Park, J.H.;Kim, S.D.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.3 no.4
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    • pp.1-7
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    • 2006
  • A water hydraulic pump is likely to have serious problems of high leakage, friction and low energy efficiency. A water hydraulic pump has commonly a fixed displacement type and its outlet flow is adjusted by controlling rotation speed of the pump, which can be implemented by using an electric inverter. This study aims to investigate energy efficiency of the water hydraulic pump system which is driven by an electric inverter. The study is based on the experimental results. The pump which is used in the study shows relatively good efficiency and low leakage, low friction as well. The reasons for the good performance of pump is also investigated.

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An Analysis of Economic Efficiency of Environmental Friendly Farms and Conventional Farms : the Case of Strawberries and Tomatoes farms (친환경농가와 관행농가의 경영효율성에 관한 연구: 딸기와 토마토를 중심으로)

  • Han, Byeol;Yang, Sung-Bum
    • Korean Journal of Organic Agriculture
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    • v.25 no.4
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    • pp.679-697
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    • 2017
  • This study analyzes an economic efficiency of environmental friendly farm and conventional farm using the data envelopment analysis (DEA). We compare the economic efficiency of Environmental Friendly farm and Conventional farm. We also analyze the effects of some explanatory variables on allocative efficiency (AE), pure technology efficiency (PTE) and scale efficiency (SE). In the case of strawberries farm, environmental friendly farm has higher overall efficiency (OE) than conventional farm. But tomatoes farm has higher overall efficiency (OE) than conventional farm. And We measure returns to scale of farms. Most strawberries and tomatoes farms showed Increasing to Scale (IRS).

Uncertainty of Efficiency Equation of Solar Thermal Collectors (태양열 집열기 효율식의 불확도)

  • Lee, Kyoung-Ho;Lee, Soon-Myung
    • 한국신재생에너지학회:학술대회논문집
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    • pp.65.1-65.1
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    • 2010
  • Thermal performance tests of solar thermal collectors include determination of coefficient parameters in an efficiency equation. The parameters can be estimated using regression method to minimize an objective function as sum of differences between measured efficiency data and regressed efficiency equation. However, this conventional approach doesn't consider measurement uncertainties. In this presentation, a method to determine regression parameters in the efficiency equation and uncertainties of the parameters is described with mainly mathematical expressions based on literature reviews. In the method, parameters in the equation for collector efficiency can be determined using regression analysis with a weighting factor in the objective function. The weighting factor can be uncertainties of the differences between measured and fitted efficiencies. To evaluate the approach, performance estimation of a solar collector using the efficiency equation with uncertainties is compared to the result using the conventional efficiency equation by a simulated way for a case in one of previous studies.

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Policy Direction for Subsidizing Hospitals based on Technical Efficiency (병원도산분석에 기초한 효율적인 병원지원방안에 관한 연구)

  • Jung, Ki-Taig;Lee, Hoon-Young
    • Korea Journal of Hospital Management
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    • v.4 no.2
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    • pp.219-241
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    • 1999
  • This study used the Data Envelopment Analysis, a mathematical linear programming method, to evaluate cost efficiency of hospitals in Korea. DEA method was applied to 244 hospitals: 31 bankrupt hospitals and 213 survived hospitals. Among the 213 sound hospitals, 11 hospitals showed efficiency score 100, but more than 40 hospitals recorded efficiency scores lower than 60. This result implies that more hospitals can be bankrupt in the restructuring process of the industry within 1-2 years. Among the 31 bankrupt hospitals, the highest technical efficiency score was 0.821 and 11 hospitals showed technical efficiency lower than 0.6. This implies that selective financial support based on cost efficiency by the government will be valuable to prevent bankruptcy of these hospitals. The logistic analysis showed statistically significant relationship between bankruptcy and efficiency of hospitals in Korea.

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Imprecise DEA Efficiency Assessments : Characterizations and Methods

  • Park, Kyung-Sam
    • Management Science and Financial Engineering
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    • v.14 no.2
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    • pp.67-87
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    • 2008
  • Data envelopment analysis (DEA) has proven to be a useful tool for assessing efficiency or productivity of organizations which is of vital practical importance in managerial decision making. While DEA assumes exact input and output data, the development of imprecise DEA (IDEA) broadens the scope of applications to efficiency evaluations involving imprecise information which implies various forms of ordinal and bounded data possibly or often occurring in practice. The primary purpose of this article is to characterize the variable efficiency in IDEA. Since DEA describes a pair of primal and dual models, also called envelopment and multiplier models, we can basically consider two IDEA models: One incorporates imprecise data into envelopment model and the other includes the same imprecise data in multiplier model. The issues of rising importance are thus the relationships between the two models and how to solve them. The groundwork we will make includes a duality study which makes it possible to characterize the efficiency solutions from the two models. This also relates to why we take into account the variable efficiency and its bounds in IDEA that some of the published IDEA studies have made. We also present computational aspects of the efficiency bounds and how to interpret the efficiency solutions.