• Title/Summary/Keyword: efficiency Analysis

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Equivalent Circuit Analysis of Single Phase Induction Motor Considering Magnetic Saturation Characteristics (자기포화 특성을 고려한 단상유도전동기의 등가회로 해석)

  • Kim, Young Sun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.2
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    • pp.270-277
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    • 2013
  • Single phase induction motor(SPIM) is used widely because it is driven by single phase source. However, the efficiency of the motor is not good due to saturation of magnetic material. To analyze the motor accurately, the magnetic saturation characteristics should be considered in analysis of equivalent circuit. In this paper, lumped parameter of circuit are derived from multi phase induction motor using method of symmetrical coordinates. Also, we presents a method for the equivalent circuit analysis of SPIM using magnetic saturation rate. The magnetic nonlinearity is considered deriving magnetizing reactance from voltage-current saturation curve. As a results, current characteristic, torque, output and efficiency are shown through analysis of equivalent circuit. A simulation results of SPIM will be used to improve the characteristics and efficiency of motor.

The DEVELOPMENT OF WORK PERFORMANCE ANALYSIS SYSTEM

  • Lim, Chul-Woo;Yu, Jung-Ho;Kim, Chang-Duk
    • International conference on construction engineering and project management
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    • 2009.05a
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    • pp.738-746
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    • 2009
  • The purpose of this study is to develop the web-based system for work performance analysis(WPAS). The need of work performance analysis system has already been suggested in many previous researches on the computerization of the performance measurement in the construction site by using the indicators such as time, cost and quality. However, they had focused on measuring or analyzing the result when the project would be over. The WPAS suggests three indicators - work reliability, work effectiveness and work efficiency - to manage the performance of the construction site. It can help the manager more easily recognize the status of on-going work in the construction site by measuring and analyzing the work reliability rate, the work effectiveness and work efficiency every day. This research includes the procedures for WPAS measurement process, database structure of WPAS which was analyzed by the IDEF0 and the data flow diagram. Finally, this research introduces the result of WAPS's case studies and validation in the Korean construction site.

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A Study on the Efficiency of Strategy of Korean Companies in India (한국기업의 인도진출 전략의 효율성에 관한 연구)

  • Kim, Changbong;Shim, Seop
    • International Commerce and Information Review
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    • v.19 no.3
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    • pp.45-61
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    • 2017
  • The purpose of this study is to examine the efficiency of Korean companies' entry strategy in India through the DEA model and to review the current status and competitiveness of Korean companies in India. To analyze 112 companies that entered India in analyzing the common variables among the major variables related to Korean companies' entry strategy into India. To measure efficiency, 'DEAR 2.1' An output - oriented CCR model and BBC model were used for the analysis to minimize the input and maximize the output factor. The results of the study on the relative efficiency analysis of the investment strategy of the companies in India are as follows. First, six firm was analyzed efficiently in the CCR model and most firms showed inefficiency in management. Second, even with the BCC model, which represents pure technology efficiency, 103 companies were analyzed efficiently as well. Unlike the CCR, overall technology efficiency of firms was high. Third, as a result of analyzing the efficiency of the scale, it was found that six company showed efficient efficiency, and most of the companies showed inefficiency overall. Companies with inefficiencies should increase efficiency by expanding their scale. Based on the above analysis, it is expected that the companies that will enter India in the future should secure the human and material resources to realize economies of scale considering the number of employees, investment scale, investment type and industry.

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An Analysis of Management Performance and Efficiency of Medician Crop Farm - Mainly on Angelica dahurica and Bupleurum falcatum - (약용작물의 경영성과와 효율성 분석 -구릿대와 시호를 중심으로-)

  • Choi, Don-Woo;Lim, Cheong-Ryong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.6
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    • pp.400-406
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    • 2017
  • This study was conducted to provide improvement measures for Korea's medicinal crop farmers whose business has been severely damaged by imported medicinal herbs. To accomplish this, the performance and efficiency of farming Angelica dahurica and Bupleurum falcatum were analyzed. The results of the analysis can be summarized as follows. First, the farming households cultivating Angelica dahurica had an average revenue of 1,363,000 KRW per 10 acres. The average income per 10 acres was 500,000 KRW, and the income ratio was 36.7%. Second, the farming households cultivating Bupleurum falcatum had an average revenue of 1,705,000 KRW per 10 acres, with an average income per 10 acres of 873,000 KRW and an income ratio of 44.6%. Third, the farming households cultivating Angelica dahurica were found to have a technical efficiency of 0.790, a pure technical efficiency of 0.856, and a scale efficiency of 0.924. Fourth, the farming households cultivating Bupleurum falcatum were found to have a technical efficiency of 0.670, a pure technical efficiency of 0.794, and a scale efficiency of 0.844. Both Angelica dahurica and Bupleurum falcatum farming households showed relative differences in technical efficiency. The pure technical aspects, rather than the scale aspects, were shown to contribute more to the differences.

The Efficiency of Social Value Among Social Enterprises in Social Progress Credit (사회성과인센티브 참여기업의 사회적 가치 효율성)

  • Wonhee, Lee;Sunghee, Lee
    • Journal of Korea Society of Industrial Information Systems
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    • v.28 no.1
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    • pp.71-82
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    • 2023
  • As an alternative to solving social problems, social economic actors are attracting attention as an important alternative. SPC is a private program that pays incentives according to the social performance measured by monetary value. This study measured efficiency by applying DEA to social enterprises that participated in the SPC program and analyzed the factors affecting efficiency through tobit regression. As a result of DEA analysis, it was found that 21% of social enterprises participating in SPC were efficient, but 66% needed to improve their efficiency. In the Tobit regression analysis, the efficiency was relatively low in the case of manufacturing sector, and when the square term of sales is included, the efficiency decreases as sales increase. Through this, it was estimated that external support is needed at a low level sales before crossing the critical point, and that the efficiency of social value creation increases when it grows above a certain level. Moreover, it is significant in that it combines the variables used in the analysis of traditional industrial efficiency while conducting efficiency analysis focusing on the social performance by monetary value, which is considered the most important achievement of social enterprises. It is believed that it will contribute to research related to the environment creation and the requirements of each field in creating social values for social enterprises in the future.

An Analysis on Management Efficiency of The Regional Public Hospitals Using D.E.A (DEA를 이용한 지방의료원 경영효율성 분석)

  • Kim, Young-Jong;Kim, Kwang-Hwan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.8
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    • pp.512-520
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    • 2020
  • This study analyzed the relative operational efficiency and impact factors of regional public hospitals to present benchmarking points for enhancing the efficiency of inefficient regional public hospitals. The survey targets collected and utilized the internal resources and management performance data from 34 regional public hospitals in Korea over the past five years, from 2014 to 2018. The final 33 regional public hospitals were surveyed, excluding Jinan Regional Public Hospital, which opened in 2015, the middle of the survey period. The general characteristics and input/output variables were analyzed by frequency analysis and technical statistics analysis, and Data Envelopment Analysis was performed to measure the operational efficiency index and relative comparison. According to the study, there were 11 efficient hospitals (33.3%) and 22 inefficient hospitals (66.7%). Of the 22 inefficient hospitals, 13 (IRS: Increasing Returns to Scale) required scale expansion, and nine (DRS: Decreasing Returns to Scale) required scale reduction or rebalancing. The significance of this study was that an analysis of the relative efficiency and influencing factors presented specific alternatives or directions that could help enhance the efficiency of the growth of regional public hospitals, sustainable management, and expansion of publicness.

Production Efficiency Analysis of Offshore and Coastal Fisheries Considering Greenhouse Gas (온실가스를 고려한 연근해어업의 생산효율성 분석)

  • Jeon, Yonghan;Nam, Jongoh
    • Environmental and Resource Economics Review
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    • v.30 no.1
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    • pp.79-105
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    • 2021
  • In the circumstance of standing out the climate change issue, the purpose of this study is to compare the efficiency of offshore and coastal fisheries according to whether or not greenhouse gas (GHG) emissions are considered, and then to present policy alternatives based on the analysis results. For analysis, the traditional data envelopment analysis (DEA), the slacks-based measure (SBM) and the SBM-undesirable models were used, and robust analysis of variance (ANOVA) and Wilcoxon Signed-rank tests were performed. As a result, the study showed that the average efficiency of fisheries decreased as the traditional DEA extended to the SBM model considering the slack and the SBM-undesirable model including the GHG emissions. Specifically, the average efficiency of the traditional DEA model, SBM model, and SBM-undesirable model was analyzed as 0.7350, 0.5820 and 0.4976 respectively. In addition, the results of the robust ANOVA and Wilcoxon Signed-rank tests all showed that there are statistically significant differences in efficiency between offshore and coastal fisheries as well as among traditional DEA, SBM and SBM-undesirable models. As a policy alternative to the analysis, it was suggested that to improve the efficiency of coastal and offshore fisheries, it is necessary to actively implement the new fishing vessel project and develop smart and electric hybrid fishing vessels.

Evaluating Efficiency of Life Insurance Companies Utilizing DEA and Machine Learning (자료봉합분석과 기계학습을 이용한 생명보험회사의 효율성 평가)

  • Hong, Han-Kook;Kim, Jae-Kyeong
    • Journal of Intelligence and Information Systems
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    • v.7 no.1
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    • pp.63-79
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    • 2001
  • Data Envelopment Analysis(DEA), a non-parametric productivity analysis tool, has become an accepted approach for assessing efficiency in a wide range of fields. Despite of its extensive applications and merits, some features of DEA remain bothersome. DEA offers no guideline about to which direction relatively inefficient DMUs improve since a reference set of an inefficient DMU, several efficient DMUs, hardly provides a stepwise path for improving the efficiency of the inefficient DMU. In this paper, we aim to show that DEA can be used to evaluate the efficiency of life insurance companies while overcoming its limitation with the aids of machine learning methods.

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Study on the Performance Analysis of an Axial-Type Turbine with Steam Injection (증기가 분사된 축류형 터빈의 성능해석에 관한 연구)

  • Cho, Soo-Yong;Kim, Soo-Yong
    • The KSFM Journal of Fluid Machinery
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    • v.4 no.4 s.13
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    • pp.28-36
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    • 2001
  • Performance analysis is conducted on an axial-type turbine which is used for fire extinction by injecting water or steam into the turbine. Loss models developed by Hacker and Okapuu are applied for predicting the performance of turbine. Pressure loss generated through a turbine is converted to the thermal efficiency, and thermal and gas properties are calculated within a turbine passage. Total-to-total efficiency, total-to-static efficiency, static temperature at the exit of turbine, output power, flow coefficient, blade loading coefficient, and expansion ratio are predicted with changing the amount of injected steam and the rotational speed. The 74 kW class gas turbine developed at KIMM is chosen for performance analysis. The 74 kW class turbine consists of 1 stage like a current developing gas turbine for fire extinction. Water or steam is injected at the end of combustor, and results show that efficiency and output power are dependent on the temperature of injected water or steam and the static temperature at the exit is decreased.

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Evaluation of Operation Efficiency in the Korean RCC/RSC Using Fuzzy-Logic and DEA (퍼지로직과 DEA를 이용한 RCC/RSC별 운영효율성 평가)

  • Jang, Woon-Jae;Keum, Jong-Soo
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.12 no.4 s.27
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    • pp.233-239
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    • 2006
  • This paper aims to evaluate the operation efficiency of Korean RCC(Rescue Co-ordination Center)/RSC(Rescue Sub-Center) using DEA(Data Envelopment Analysis). for this evaluation, this paper use the quantitative data for DEA analysis with two inputs and four outputs and a qualitative data analysis with the use of expert assessment. The tool for integrating heterogeneous data is fuzzy logic model to decision support system. In this paper, therefore, RCC/RSC evaluates the priority for operation efficiency. The result are found as order as Inchon, Mokpo, Jeju, Donghae, Busan, Pohang, Yosu, Sokcho, Tongyeong, Ulsan, Taean, Gunsan RSC.

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