• Earthquakes and Structures
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• 제21권5호
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• pp.551-562
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• 2021

In this study, the generalized intensity measure (IM) named I_Npg is analyzed. The recently proposed proxy of the spectral shape named N_pg is the base of this intensity measure, which is similar to the traditional N_p based on the spectral shape in terms of pseudo-acceleration; however, in this case the new generalized intensity measure can be defined through other types of spectral shapes such as those obtained with velocity, displacement, input energy, inelastic parameters and so on. It is shown that this IM is able to increase the efficiency in the prediction of nonlinear behavior of structures subjected to earthquake ground motions. For this work, the efficiency of two particular cases (based on acceleration and velocity) of the generalized I_Npg to predict the peak floor acceleration demands on steel frames under 30 earthquake ground motions with respect to the traditional spectral acceleration at first mode of vibration Sa(T₁) is compared. Additionally, a 3D reinforced concrete building and an irregular steel frame is used as a basis for comparison. It is concluded that the use of velocity and acceleration spectral shape increase the efficiency to predict peak floor accelerations in comparison with the traditional and most used around the world spectral acceleration at first mode of vibration.

• 기술혁신학회지
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• 제3권3호
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• pp.36-52
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• 2000

This study takes an issue of efficiency analysis in the presence of network effect utilizing the DEA (Data Envelopment Analysis) framework. Network effect has important policy implication for the regulation of local monopolies which undertake their business through physical network, such as electricity, natural gas, local telephony, etc. If the difference in spatial condition between companies is not controlled properly, the performance comparison and associated incentive regulation bear significant bias. In this study, we propose a methodology to measure the true managerial or technical efficiency apart from efficiency difference accruing from the difference in spatial condition. A series of modified DEA efficiency models are combined to investigate the extent of exogenous and endogenous efficiency component in the Korean natural gas distribution companies. Empirical results show that the network effect plays significant role in determining superficial performance difference.

• 가족자원경영과 정책
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• 제7권2호
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• pp.25-44
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• 2003

The purpose of the present study was to suggest the efficient communication methods for improving the quality of marriage and life in the elderly couples. For this study we considered variables connected with the communication efficiency of elderly couples. We investigated 462 elderly men and women whose spouse is alive and Seoul and the National Capital region. The major findings of this study are summarized as follows. 1) The communication efficiency of elderly couples was over than middle level so we could find that they communicate efficiently. 2) The communication efficiency of elderly couples differs significantly according to sex, education level, economic condition, health status, family type, social activity, sociotropy Personality, self-esteem, internal-external controllability, marital intimacy, relative comparison in the level of living. 3) The communication efficiency of elderly couples was dependently affected by intimacy, economic status, relationship; this variables had 40% explanation for communication efficiency.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 추계 학술논문 발표대회
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• pp.125-126
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• 2012

Domestic architect office from a period of high growth from the 1970s to the '80s has been established as some of the large corporations or publicly traded corporation. 1997 IMF has pointed out there is a lot of need for improvement activities in accordance with the construction recession since the 2008 global financial crisis. In order to address these causes, the company's continuous efficient operation for accurate efficiency and competitiveness analysis was required. Leverage financial ratio indicators Study Using Data Envelopment Analysis Data Envelopment Analysis (DEA) model, how to find a benchmark for the improvement of the efficiency of inefficient enterprises in various sectors being. In this study, a comparison of the conventional DEA model and the DEA-AR model is used to analyze the efficiency and domestic architect office is to improve the management efficiency.

• 한국경영과학회지
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• 제35권3호
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• pp.59-68
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• 2010

Improving productive efficiency is important for strengthening a competitiveness of coastal fisheries. This paper examines the productive efficiency of a sample of coastal gillnet fishing business units by estimating a stochastic frontier analysis (SFA) and a data envelopment analysis (DEA) approaches and compares those estimates obtained from two approaches. The estimated mean productive efficiency by SFA is 77.6% and the mean productive efficiencies obtained for the VRS and CRS DEA are 75.9% and 45.7%, respectively. The joint use of SFA and DEA for estimating efficiency is also discussed.

• 경영과학
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• 제26권1호
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• pp.127-136
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• 2009

This paper purposes analyzing how task assignments influence on business process efficiency, and improving business process efficiency in Business Process Management (BPM) environments. For this purpose, task assignment is categorized into dynamic assignment and static assignment. Dynamic assignment binds a user to a task at process run-time, whereas static assignments assigns a task to a user at process build-time. So far, the influence of task assignment methods has not been studied. We, in this paper, analyze the business process efficiency using two different assigning rule, in terms of cycle time as a efficiency measure. The comparison result can provide a guideline for a company who wants to employ commercial BPM systems.

• 대한안전경영과학회지
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• 제15권1호
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• pp.249-258
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• 2013

Data Envelopment Analysis (DEA) is a useful tool to analyze the relative efficiency of decision making units (DMU) characterized by multiple inputs and multiple outputs. This method has been popularly used as an analytical tool to suggest some strategic improvement. To do this, the results of DEA provide decision makers with a single efficiency score, efficient frontier, return to scale, benchmarking decision making units, etc. The purpose of this paper is to evaluate research performance of 38 universities and provide an inefficient university with the way of organizational changes to be an efficient university by using DEA. Various input and output variables are used to identify technical and scale inefficiency. Additionally, we analyze how an inefficient DMU could be changed an efficient DMU based on a case university. This result will give an insight of constructive directions for increasing of research performance to university decision makers.

• International Journal of Fluid Machinery and Systems
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• 제4권1호
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• pp.172-178
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• 2011

This paper presents an optimization procedure for high-efficiency design of a mixed-flow pump. Optimization techniques based on a weighted-average surrogate model are used to optimize a vane diffuser of a mixed-flow pump. Validation of the numerical results is performed through experimental data for head, power and efficiency. Three-level full factorial design is used to generate nine design points within the design space. Three-dimensional Reynoldsaveraged Navier-Stokes equations with the shear stress transport turbulence model are discretized by using finite volume approximation and solved on hexahedral grids to evaluate the efficiency as the objective function. In order to reduce pressure loss in the vane diffuser, two variables defining the straight vane length ratio and the diffusion area ratio are selected as design variables in the present optimization. As the results of the design optimization, the efficiency at the design flow coefficient is improved by 7.05% and the off-design efficiencies are also improved in comparison with the reference design.

• 무역학회지
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• 제46권5호
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• pp.31-47
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• 2021

Recently, third-party logistics and second-party logistics are well known as a form of logistics service. However, there are several opinions about the effectiveness of second-party logistics and third-party logistics. In this study, the efficiency of second-party logistics companies and third-party logistics companies, which are the main providers of logistics services, was compared and the sales impact on the logistics market was measured. Efficiency was measured using DEA's CCR and BCC models. Debt and equity were used as input variables, and sales, operating profit, and net income were used as output variables. As a result of measuring the efficiency of logistics companies, the efficiency of third-party logistics companies was higher than that of second-party logistics companies in 2019 and 2020, and it had a positive effect on the rate of change in sales.

• 한국태양에너지학회 논문집
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• 제35권5호
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• pp.11-19
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• 2015

In this paper, EP-Kalina cycle applying liquid-vapor ejector and motive pump is newly proposed. In this EP-Kalina cycle, the liquid-vapor ejector is used to increase pressure difference between inlet and outlet of the turbine. Also the motive pump enhances the performance of liquid-vapor ejector, resulting in increase of system efficiency of OTEC cycles. The comparison cycles in this study are basic, Kalina, EKalina and EP-Kalina ones. The pump work, net power, APRe, APRc, TPP and system efficiency of each cycle are compared. In case of net power, EP-Kalina cycle is lowest among the cycles due to the application of the motive pump. But, the net power difference of cycles seems to be minor since the pump work of cycles is merely about 1kW, compared to turbine gross power of 20kW. The system efficiency of EP-Kalina cycle shows 3.22%, relatively 44% higher than that of basic OTEC cycle. Therefore, the system efficiency is increased by applying the liquid-vapor ejector and the motive pump. Additional performance analysis is necessary to optimize the proposed EP-Kalina cycle.