• Title, Summary, Keyword: Expected efficiency

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The Machine Efficiency on the Cyclic Service System (순환서비스 시스템에서의 기계작업효율)

  • 유정상
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.9 no.13
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    • pp.33-38
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    • 1986
  • Arguments in favor of cyclic servicing, as opposed to random servicing, in connection with machines which stop in a random manner, are not conclusive because hitherto no general formular has been available for calculating the results which may be expected from cyclic servicing. The aim of the following paper is to help in evaluating the cyclic procedure by presenting a formular for calculating the standard efficiency of a group of semi-automatic machines assigned to one operator who will service them on a cyclic pattern.

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Nonparametric Selection Procedures and Their Efficiency Comparisons

  • Sohn, Joong-K.;Shanti S.Gupta;Kim, Heon-Joo
    • Communications for Statistical Applications and Methods
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    • v.1 no.1
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    • pp.41-51
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    • 1994
  • We consider nonparametric procedures for the selection and ranking problems. Tukey's generalized lambda distribution is condidered as the distribution for the score function because the distribution can approximate many well-known contionuous distributions. Also we compare these procedures in terms of efficiency, defined by the ratio of a probability of a correct selection divided by the expected selected subset size.

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Measuring the Technical Efficiency of service Operation with DEA : An Application to Call Center service (DEA 기법에 의한 서비스 운영의 기술적 효율성 분석 : 콜센터 서비스 사례연구)

  • So, Sun-Hu;Lee, Gyeong-Jae;Jo, Geon
    • Proceedings of the Korea Society for Industrial Systems Conference
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    • pp.316-321
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    • 2008
  • In the present emerging global economy, as the focus is shifted from manufacturing to service sector, the efficiency of service operations is crucial for the county's sustainable growth and development. As one of the fastest growing service sector industries in South Korea, the call center has become an inevitable part of customer service for most companies. Despite of the strategic importance of the call center, there has been no empirical study on the efficiency of call center service operations in the literature. The main purpose of this study is to evaluate the technical efficiency of call center services so as to not only identify the current status of call center service operations, but also suggest ways to improve service operations efficiency. For this purpose, we apply a non-parametric efficiency measurement method, DEA (Data Envelopment Analysis), to domestic call centers in order to compare their relative efficiency. Based on DEA evaluations, we provided specific directions for the inefficient call centers to possibly improve their operation efficiencies. It is expected that the measurement methods suggested in this study can be applied to various issues such as service KS certification, service operations management, and the productivity analysis of service personnel.

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Efficiency Analysis and Finance Strategy for an Automotive Parts Maker Using DEA and Logistic Regression Model (DEA와 로지스틱 회귀분석을 이용한 자동차부품기업의 효율성 분석 및 재무전략)

  • Sin, Jeong-Hun;Hwang, Seung-June
    • Journal of the Korean Operations Research and Management Science Society
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    • v.41 no.1
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    • pp.127-143
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    • 2016
  • This study applied DEA analysis to measure the relative efficiency of 35 companies that produce automobile body components. First, the input and output, the improvement target value of the calculated variables, and the reference group for benchmarking for inefficient groups to become efficient groups were established through DEA analysis. In addition, whether inefficiency was due to technical inefficiency or size was analyzed in connection with the cases of the actual companies through the measurement of scale efficiency. Second, a route for efficiency improvement was derived through DEA-Tier analysis by defining the possible group for benchmarking in actuality within the production industry of automobile body components where the primary cooperative company belonged. Third, the financial variables that generate the difference between efficient and inefficient groups were derived through logistic regression analysis. Financial strategies that determine the direction the indices should be improved to allow the inefficient group to become an efficient one were recommended. This research is expected to provide diagnostic methods for management efficiency and the direction of improvement to enhance the management efficiency of automotive parts makers by identifying the causes of the inefficiency of domestic automotive parts makers empirically. The study also provides financial strategies together with the target values of efficiency improvement for each individual company.

New High-efficiency Power Amplifier System for High-directional Piezoelectric Transducer (고지향성 압전 트랜스듀서용 새로운 고효율 전력 증폭기)

  • Kim, Jin-Young;Kim, In-Dong;Moon, Wonkyu
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.3
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    • pp.383-390
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    • 2018
  • Piezoelectric micro-machined ultrasonic transducers for highly directional speaker need DC bias voltage. Most existing power amplifiers are not suitable for use in highly directional transducers because they are based on AC. In addition, since the piezoelectric micro-machined ultrasonic transducer has a large capacitive reactance, the power efficiency of the power amplifier is very low. Thus this paper proposes a new high efficiency power amplifier with DC bias voltage. In addition, by designing a matching circuit to compensate the capacitive reactance of the micro-machined ultrasonic transducer, the power efficiency of the power amplifier increases. The operating characteristics of the proposed power amplifier was verified by an experimental prototype. The proposed power amplifier is expected to be widely used in designing and implementing other related power amplifiers.

A study on the Improvement of the luminous efficiency with new sustaining electrode structurs in ac-PDPs (새로운 유지전극 구조에 의한 ac-PDP 에서의 효율 개선에 관한 연구)

  • Lee, Jae-Young;Shin, Joong-Hong;Park, Chung-Hoo;Cho, Jung-Soo
    • Proceedings of the KIEE Conference
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    • pp.1818-1820
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    • 2000
  • Due to recent technology advances, needs for flat panel displays, plasma display panels(PDPs) whose advantages are simple structure, high resolution, wide viewing angle is increasingly expected to be the first flat panel of large screen, walt hanging TVs. But the luminance and luminous efficiency of color PDP is net up to the level of a CRT. So, New electrode shape which is different from the conventional electrode has to propose to improve the luminance and luminous efficiency. In this paper, we suggested new shaped electrodes. In new shaped electrode, the discharge current was reduced compared with conventional type by reducing the unnecessary diffusion loss near the barrier rib. However, the luminance was nearly the same as conventional type. So, the luminous efficiency improved about 35%.

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Calculation of Spectral Efficiency for Estimating Spectrum Requirements of IMT-Advanced in Korean Mobile Communication Environments

  • Chung, Woo-Ghee;Lim, Eun-Taek;Yook, Jong-Gwan;Park, Han-Kyu
    • ETRI Journal
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    • v.29 no.2
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    • pp.153-161
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    • 2007
  • In this paper, we analyze the algorithm of the methodology developed by ITU for the calculation of spectrum requirements of IMT-Advanced. We propose an approach to estimate user density using traffic statistics, and to estimate spectrum efficiencies using carrier-to-interference ratio distribution and capacity theory as well as experimental data under Korean mobile communication environments. We calculate the IMT-Advanced spectrum requirements based on the user density and spectral efficiencies acquired from the new method. In the case of spectral efficiency using higher modulation and coding schemes, the spectrum requirement of IMT-Advanced is approximately 2700 MHz. When applying a $2{\times}2$ multiple-input multiple-output (MIMO) antenna system, it is approximately 1500 MHz; when applying a $4{\times}4$ MIMO antenna system, it is approximately 1050 MHz. Considering that the development of new technology will increase spectrum efficiency in the future, the spectrum requirement of IMT-Advanced in the Korean mobile communication environment is expected to be approximately 1 GHz bandwidth.

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A Study on the Solar Cell Charging Equipment for Hybrid Vehicle (Hybrid 자동차용 Solar Cell 충전장치에 관한 연구)

  • Kim, G.S.;Park, S.C.
    • Journal of the Korean Society of Mechanical Technology
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    • v.13 no.4
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    • pp.157-164
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    • 2011
  • Hybrid car can improve fuel efficiency using a power of motor that is generated during constant-speed or deceleration driving. The motor is located between engine and transmission. But, when voltage of main battery is low, fuel efficiency is low because the voltage can't run the motor. In this situation, this study observed fuel efficiency when using solar cell for assistance power. In order to verify a fuel consumption of hybrid car equipped solar cell for assistance power, the car was tested downtown driving. As hybrid car was equipped solar cell for assistance, fuel consumption was reduced 8.35 % at running air conditioner. And, at air conditioner doesn't work, fuel consumption was reduced 6.88 %. This point of view, CO2 is expected to reduce in similar proportion.

Development of a simplified model to maximize operating efficiency of heat exchanger (지중 열 교환기 운영 효율의 최적화를 위한 단순화 모델의 개발)

  • Kim, Kyung-Ho;Shin, Ji-Youn;Kim, Seong-Kyun;Lee, Kang-Kun
    • 한국신재생에너지학회:학술대회논문집
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    • pp.481-484
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    • 2007
  • Efficiency of geothermal heat exchanger operation has close relation with temperature variation of the aquifer where the exchanger is installed. In the case of long-term operation, temperature distribution of the aquifer would be similar to that of water circulating in the exchanger, which causes the decrease of heat exchange rate. Therefore, the operation period of the heat exchanger should be controlled so that the temperature distribution of the aquifer is recovered. We developed a model to determine the operation period to acquire the optimal efficiency under the given aquifer condition. With this suggested method, when we use closed-loop heat exchanger, the operation efficiency of the geothermal heat exchanger is expected to be maximized by determining the optimal operation period.

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A Study on Unified Packing Standard for Agricultural Products Based on Pallet Stacking Efficiency (팔레트 적재효율을 고려한 농산물 포장상자 통합규격에 관한 연구)

  • Suh, Kyo;Lee, Jeong-Jae;Suh, Byong-Yoon
    • Journal of The Korean Society of Agricultural Engineers
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    • v.47 no.1
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    • pp.13-22
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    • 2005
  • Despite the variety in sizes and shapes of agricultural products, the unified standardization of packing has been a long time necessity. In this study the stacking efficiency of packing standards for each box using packing Monte Carlo simulation based on the standard pallet is evaluated. As a result of simulation the unified packing standard for agricultural products is suggested by 550$\times$366 mm. With this study it is expected that the unification of the standards can help to increase the utilization of reusable packages and to improve efficiency of agricultural logistics.