• Title/Summary/Keyword: relative efficiency

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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.

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.

Organizational Determinants related with Relative Efficiency of the Community Mental Health Centers (지역사회 정신보건센터의 상대적 효율성에 영향을 미치는 조직관련 특성)

  • 김성옥
    • Health Policy and Management
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    • v.11 no.2
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    • pp.58-84
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    • 2001
  • This study was conducted to explore the relationship between the efficiency and its organizational determinants of tile Community Mental Health Centers(CMHCs). Data are obtained from 81 personnel of 27 CMHCs from Sept. to Oct. in 1999(19 in Kyunggi province, 7 in Seoul City and 1 in Chunchon, Kangwon province). Major findings of this study are as follows. 1. DEA is a mathematical programming technique that optimizes the relative efficiency ratio of inputs over outputs for each decision-making unit(DMU). It produces a summary scalar efficiency ratio for each DMU of CMHCs. It assessed multiple inputs and multiple outputs simultaneously, and compared to specific peer group of CMHCs. 2. Organizational determinants of DEA efficiency of CMHCs we proved as advertisement(+), location of CMHCs(in public facility)(+), area of facility(+), period of operation(+), job satisfaction(+), clarity of work-role(vague), cohesion(-), rate of certified personnel(+), number of referral(+), and voluntary service time(-).

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NUMERICAL STUDY ON THE CLOCKING EFFECT IN A 1.5 STAGE AXIAL TURBINE (1.5단 축류터빈에서의 Clocking 효과에 관한 수치적 연구)

  • Park, Jong-Il;Choi, Min-Suk;Baek, Je-Hyun
    • Journal of computational fluids engineering
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    • v.11 no.4 s.35
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    • pp.1-8
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    • 2006
  • Clocking effects of a stator on the performance and internal flow in an UTRC 1.5 stage axial turbine are investigated using a three-dimensional unsteady flow simulation. Six relative positions of two rows of stator are investigated by positioning the second stator being clocked in a step of 1/6 pitch. The relative efficiency benefit of about 1% is obtained depending on the clocking positions. However, internal flows have some different characteristics from that in the previous study at the best and worst efficiency positions, since the first stator wake is mixed out with the rotor wake before arriving at the leading edge of the second stator. Instead of the first stator wake, it is found that the wake interaction of the first stator and rotor has a important role on a relative efficiency variation at each clocking position. The time-averaged local efficiency along the span at the maximum efficiency is more uniform than that at the minimum efficiency. That is, the spanwise efficiency distribution at the minimum efficiency has larger values in mid-span but smaller values near the hub and casing in comparison to those at the maximum efficiency. Moreover, the difference between maximum and minimum instantaneous efficiencies during one period is found to be smaller at the maximum efficiency than at the minimum efficiency.

Numerical Study on the Clocking Effect in a 1.5 Stage Axial Turbine (1.5단 축류 터빈에서의 Clocking 효과에 관한 수치적 연구)

  • Park, Jong-Il;Choi, Min-Suk;Baek, Je-Hyun
    • 유체기계공업학회:학술대회논문집
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    • 2005.12a
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    • pp.473-480
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    • 2005
  • Clocking effects of a stator on the performance and internal flow in an UTRC 1.5 stage axial turbine are investigated using a three-dimensional unsteady flow simulation. Six relative positions of two rows of stator are investigated by positioning the second stator being clocked in a step of 1/6 pitch. The relative efficiency benefit of about 1% is obtained depending on the clocking positions. However, internal flows have some different characteristics from that in the previous study at the best and worst efficiency positions, since be first stator wake is mixed out with the rotor wake before arriving at the leading edge of the second stator. Instead of the first stator wake, it is found that the wake interaction of the first stator and rotor has a important role on a relative efficiency variation at each clocking position. The time-averaged local efficiency along the span at the maximum efficiency is more uniform than that at the minimum efficiency. That is, the spanwise efficiency distribution at the minimum efficiency has larger values in mid-span but smaller values near the hub and casing in comparison to those at the maximum efficiency. Moreover, the difference between maximum and minimum instantaneous efficiencies during one period is found to be smaller at the maximum efficiency than at the minimum efficiency.

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Relative Efficiency of Jeju Self-Governing Schools (제주형 자율학교 상대적 효율성 분석)

  • Lee, In-Hoi;Kim, Min-Hee
    • The Journal of the Korea Contents Association
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    • v.15 no.3
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    • pp.477-487
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    • 2015
  • The purposes of this study was to analyze the relative efficiency of nineteen Jeju Self-Governing Schools (JSGS) in elementary level by using DEA (Data Envelopment Analysis). Major results from the study are as follows: First, there were significant differences on the relative efficiency among JSGS, which might come from operation factors rather than from size factors of JSGS. Second, to improve the relative inefficiency of JSGS, it is quite suggestive that satisfaction of both students and parents would be developed, and that the quality of educational programs should be developed by analyzing especially parents characteristics and reflecting their needs. Lastly, the perspective of efficiency, which is a measure of the optimal usage of available school resources, should be adopted and used for school assessment in order to develop the relative efficiency of JSGS.

A Study on the Mass Collection Efficiency in Collector Step of Electrostatic Precipitator by Physical Gas Characterization (전기집진장치에서 가스의 물리적인 특성에 따른 포집구역내의 입자포집율 연구)

  • Ha, Sang-An;Im, Gyeong-Taek;Sin, Nam-Cheol
    • Journal of Environmental Science International
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    • v.7 no.1
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    • pp.36-40
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    • 1998
  • This study was carried out to investigate the collection Efficiency of mass in collector step at the different of physical gas characterization. This work has focused on the dependence of the collection efficiency of mass in the collector zone of a two-stage set up field with gas temperature T and the dew point tmeperature. To identify the dependence of the mass collection efficiency on the Bounded plate of the collector zone MP.k by the spectre electric resistance of dust $p_e$. and the relative humidify ${\varphi}$, 20 at- tempts have been made with three different gas temperature ($50{\circ}C, 80{\circ}C, 110{\circ}C$) at different dew point. At the specific electric resistance of dust $p_e$=$10^6{\Omega}m$ which relative humidity corresponds to $\phi$ > 15%, a easy rise of the sounded plate secluded dust mass share was measured atwain. As the result of the higher cohesion imprisonment power due to the adsorbtion of particle, the rinse of the relative humidity developed on the particle surface. Therefore, the collection efficiency of mass was not predominant the high temperature T in the collector zone, neither was the pecific ellectric resistance of dust dependent.

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Relative Efficiency of Taxi Services by Data Envelopment Analysis among Cities and Counties in Gyeonggi Province (DEA를 이용한 경기도내 시·군별 택시서비스 효율성 분석)

  • Kim, Dae Hoon;Jang, Tae Youn;Song, Je Ryong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.4
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    • pp.1571-1580
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    • 2013
  • This study analyzes the relative efficiences through satisfaction on taxi services of thirty-one cities and counties in Gyeonggi Province. The DEA (Data Envelopment Analysis) is used to measure efficiencies on the privately owned taxies and the corporate taxies respectively. Efficiency in the DEA is measured relative to the highest observed performance rather than against some average. Pyeongtaek, Pocheon, Osan, Yangpyeong, and Gapyeong have the highest efficiency in the private owned taxies. And Pyeongtaek, Pocheon, Osan, and Gapyeong have the highest one in the corporate taxies. These cities and counties have the ability to use less resources for equal efficiency relative to others. Rank-sum test proves that there is no statistical difference in efficiency between the privately owned taxies and the corporation owned taxies.

Analysis of Factors Affecting the Smoking Rates Gap between Regions and Evaluation of Relative Efficiency of Smoking Cessation Projects (지역 간 흡연율 격차 영향요인 분석 및 금연사업 상대적 효율성 평가: Clustering Analysis와 Data Envelopment Analysis를 활용하여)

  • Kim, Heenyun;Lee, Da Ho;Jeong, Ji Yun;Gu, Yeo Jeong;Jeong, Hyoung Sun
    • Health Policy and Management
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    • v.30 no.2
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    • pp.199-210
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    • 2020
  • Background: Based on the importance of ceasing smoking programs to control the regional disparity of smoking behavior in Korea, this study aims to reveal the variation of smoke rate and determinants of it for 229 provinces. An evaluation of the relative efficiency of the cease smoking program under the consideration of regional characteristics was followed. Methods: The main sources of data are the Korean Statistical Information Service and a national survey on the expenditure of public health centers. Multivariate regression is performed to figure the determinants of regional variation of smoking rate. Based on the result of the regression model, clustering analysis was conducted to group 229 regions by their characteristics. Three clusters were generated. Using data envelopment analysis (DEA), relative efficiency scores are calculated. Results from the pooled model which put 229 provinces in one model to score relative efficiency were compared with the cluster-separated model of each cluster. Results: First, the maximum variation of the smoking rate was 16.9%p. Second, sex ration, the proportion of the elder, and high risk drinking alcohol behavior have a significant role in the regional variation of smoking. Third, the population and proportion of the elder are the main variables for clustering. Fourth, dissimilarity on the results of relative efficiency was found between the pooled model and cluster-separated model, especially for cluster 2. Conclusion: This study figured regional variation of smoking rate and its determinants on the regional level. Unconformity of the DEA results between different models implies the issues on regional features when the regional evaluation performed especially on the programs of public health centers.

Effect of dielectric barrier discharge parameters on degradation efficiency of ethyl acetate

  • Deng, Xu;Lu, SiHeng;Zheng, Kun;Yu, ZhiMin
    • Journal of Urban Science
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    • v.8 no.2
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    • pp.13-18
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    • 2019
  • Using self-made coil dielectric barrier discharge reactor, the removal efficiency of ethyl acetate under simulated experimental parameters such as initial concentration of waste gas, total flow rate, relative humidity and voltage was investigated. The results show that the degradation rate of ethyl acetate increases with the increase of output voltage. When other conditions remain unchanged, the degradation rate decreases with the increase of initial concentration of ethyl acetate; with the increase of total flow rate, the degradation rate of ethyl acetate decreases; with the increase of relative humidity, the degradation rate first increases and then decreases, and when the relative humidity is 64%, the degradation efficiency is the highest.