• Journal of Korean Society for Quality Management
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• v.37 no.1
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• pp.80-90
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• 2009

Nowadays, there are many companies which employ the SQI measurement to assess service quality. The purpose of this study is to measure the service efficiency for Bank Industry. In this paper, we tried to measure the efficiency of service quality and overall customer satisfaction by using Data Envelopment Analysis(DEA). Rather than using the usual method of converting the Service Quality Index(SQI) into mean value, we applied CCR/BCC models in DEA to service quality efficiency. Also, DEA/PS Model is recommended as appropriate model for evaluating service efficiency by complementing the shortfalls of the weighted value of DEA Model. In this study, six dimensions of service quality were considered as input variables and output variables(overall customer satisfaction, reusing intention, and word of mouth). The result of this study statistically verifies that 5 DMUs are relatively efficient, and intensive activities for service efficiency are needed for 20 sample branches. Managerial implications based on the analysis were suggested.

• Journal of Distribution Science
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• v.12 no.8
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• pp.5-15
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• 2014

Purpose - The method of TV home shopping is a kind of retail method that provides the viewer with information about products and, further, sells the products to consumers through the media of television. The domestic home-shopping industry has been expanding since 1995, and there are six companies in this arena as of 2012. In this study, we evaluate the management efficiency of TV home-shopping companies and provide suggestions for improving efficiency, using the DEA (data envelopment analysis) model. Hence, we expect to contribute to the progress of the companies' efficiency and the development of the TV home-shopping industry, where deepening competition is inevitable because it is experiencing the maturing market stage in its life cycle. Research design, data, and methodology - Efficiency is the ratio of the quantity of input to the quantity of output of a product or service. It is necessary to estimate aggregate inputs and aggregate outputs, which are calculated by applying a weighting to a number of input and output factors, to measure the efficiency. The DEA model is divided into the CCR model and the BCC model. The CCR model is a basic model that assumed constant returns to scale (CRS), and the BCC model extends the CCR model to accommodate technologies exhibiting variable returns to scale (VRS), and concerns only the technical efficiency without considering the efficiency of returns to scale. In this study, we consider six companies each year from 2008 to 2012 as a DMU (Decision Making Unit) and analyze the differences in efficiency for each company in each year. Furthermore, we evaluate the operating characteristics of TV home-shopping companies, using three models, in accordance with the overall performance, profitability, and marketability of the business. Results - The result of the analysis, using DEA models, shows that Hyundai Home Shopping (2009, 2010, 2011), GS Home Shopping (2011), NS Home Shopping (2011) and CJ O Shopping (2012) possess MPSS (most productive scale size), with a score 1.0 in CCR, BCC, and scale efficiency. Particularly, Hyundai Home Shopping is shown to be the most efficient in terms of overall business performance, marketability, and profitability. The overall efficiency of the home shopping industry has displayed an increasing trend since 2008, even though it decreased marginally in 2012; further, we can observe that home shopping companies operate with increasing efficiency with the passage of time. Conclusions - Home shopping companies have focused on market expansion rather than profits, as they displayed better efficiency in marketability than increase in profitability during the period 2008-2012. In addition, the main reason for the increased efficiency in the home shopping industry is the market expansion through the revenue increase of each home shopping company. This study can be used as a reference when home shopping companies attempt to devise future strategies, as it suggests efficiency benchmarks and development levels for each home shopping company.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.6
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• pp.2129-2137
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• 2010

In this research, we analyze the efficiency of 20 public health centers of Gyeongnam Province, so the reduction and weakness of input and output factor were found. We used the CCR, BCC model of Data Envelopment Analysis as a method of evaluation, made a choice human resource as the input variable, made a selection the performance of health care center, ward as the output variable. The results show that 12(60%) public health centers in 20 were productive with respective to overall Technical Efficiency(average score 0.868), 14(70%) with respective to overall Pure Technical Efficiency(average score 0.924) and 12(60%) with respective to overall Scale Efficiency(average score 0.933). It is expected that this research can provide a good data for effective management of public health centers.

• Journal of Power Electronics
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• v.17 no.1
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• pp.200-211
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• 2017

Conventional boost-full-bridge and boost-hybrid-bridge two-stage inverters are widely applied in order to adapt to the wide dc input voltage range of photovoltaic arrays. However, the efficiency of the conventional topology is not fully optimized because additional switching losses are generated in the voltage conversion so that the input voltage rises and then falls. Moreover, the electrolytic capacitors in a dc-link lead to a larger volume combined with increases in both weight and cost. This paper proposes a higher efficiency inverter with time-sharing synchronous modulation. The energy transmission paths, wheeling branches and switching losses for the high-frequency switches are optimized so that the overall efficiency is greatly improved. In this paper, a contrastive analysis of the component losses for the conventional and proposed inverter topologies is carried out in MATLAB. Finally, the high-efficiency under different switching frequencies and different input voltages is verified by a 3 kW prototype.

• The KSFM Journal of Fluid Machinery
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• v.11 no.6
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• pp.7-17
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• 2008

Fan performances are obtained with various tip clearance gaps and stagger angles of the rotor. A tested fan is an axial-type fan of which the casing diameter is 806 mm. Two different rotors are applied to this test. One is designed on the basis of the free vortex method along the radial direction and the other is designed using the forced vortex method. The operating conditions are varied to the ultimate off-design point as well as the deign point. Overall efficiency, total pressure and input power are compared with the tip clearance gaps and different stagger angle. The experimental results show that changing of the stagger angle has minor influence to the performance when the same rotor is applied. When the tip clearance gap is less than 5% of the rotor span, the overall efficiency, total pressure loss and input power reduction are varied linearly with the variation of the tip clearance gaps. On the design point, the overall efficiency is decreased to the rate of 2.8-2.9 to the increasing of the tip clearance, but the changing rate of the overall efficiency is alleviated when the fan operates at off-design points. In particular, this rate is more quickly declined on a fan with the rotor designed using the forced vortex method. The result of the total pressure shows that the pressure reduction rate is a 0.08-0.1 according to the tip clearance, and additionally the input power reduction rate is a 0.045-0.065 at design point.

• International Journal of High-Rise Buildings
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• v.5 no.3
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• pp.221-232
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• 2016

With the booming of construction and property industries in China, the demand for high-rises and mega-scale buildings with more integrated building functions, open- and tailor-shaped outlooks, better connections to municipal infrastructures, and higher grades of building importance has been increasing in the past two decades. The seismic design and engineering of such modern mega-buildings face engineering challenges such as hazard mitigation of extreme actions and surroundings, integrated structural frameworks and building skins, complex connections, and overall construction efficiency. It is the work of a new generation of civil and structural engineers to enhance engineering efficiency and achieve overall engineering, environmental, and economical effectiveness for these high-rise projects. This paper elaborates the above topics through case studies on the design and construction of four such developments in China. Some rethinking is conducted on evolution in modern seismic engineering and design through innovation to achieve an acceptable level of overall sustainability and building effectiveness.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.237-243
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• 2002

A centrifugal compressor of 50HP for reverse brayton cryocooler using neon as a coolent has been developed. It has relatively low total-to-total pressure ratio but mass flow rate is very small and the voting gas, neon, has greater specific heat ratio than air. It was essential to have very high rotational speed of 100,000 RPM. The efficiency of compressor has great effects on overall system and the COP of cryocooler. To meet the design requirement of the compressor efficiency and to minimized the required rotational speed, highly efficiency impeller having low specific speed was designed. To maintain the overall system efficient high, gas bearing of bump type and high speed permanent magnet synchronus motor was developed and adopted. In this paper, design and performance prediction results of the compressor impeller is presented.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.5 no.2
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• pp.91-97
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• 1976

This study was concerned with performance of 2 types of black painted solar air heaters, one is finned type better, the other is mesh type. The performance test of heaters was made under the different operating conditions during winter season of December in Seoul area. It was analized and discussed by comparing the overall efficiency of 2 solar heaters at the same mass flow rate and ambient temperature. Experimental results show that finned type solar heater is better than mesh type from the point of view of design and heat removal efficiency. Finned-type solar air heater supplies hot air up to 30 degree centigrade above ambient temperature with an overall efficiency of 47 percent whilemesh type was 44 percent.

• Korea Journal of Hospital Management
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• v.24 no.4
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• pp.57-69
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• 2019

Purpose: This study aimed to analyze the job performance efficiency of nurses in the Neonatal Intensive Care Unit (NICU) by using the Data Envelopment Analysis (DEA). Additionally, the study aimed to provide a detailed method to improve the currently inefficient way in which nurses perform their jobs by differentiating the reference group of more efficient nurses, and to compare the characteristics of the more efficient group of nurses to those of the less efficient group of nurses. Methodology: This study evaluated the relative job performance efficiency of nurses by applying DEA to 43 nurses in the NICU. The input variables for the efficiency analysis were working career (years), time spent in direct nursing care (hours), overtime (hours), and job-related training (hours); the output variables were the job performance scores of professional practice, research, leadership, and education. Data were analyzed using SPSS IBM 23.0 and Open Source DEA (OSDEA). Findings: The relative job performance efficiency of the 43 nurses was 0.933, and 20 nurses were evaluated as more efficient. In addition, the study confirmed the possibility of improving the overall job performance efficiency by improving leadership, while controlling the current input variables. Lastly, the more efficient nurses had significantly higher job performance scores for research (t=2.028, p=0.049), leadership (t=2.036, p=0.048), and education (t=2995, p=0.005) than those who were less efficient. Practical Implications: It is suggested that job performance be evaluated using DEA to improve the overall job performance efficiency of NICU nurses. The analysis results from DEA for nurses becomes evidence in support of establishing individualized goals for each nurse, thus resulting in a foundation for systematic human resource management of nurses, and ultimately contributing to increase in the job performance efficiency of nurses.

• Journal of Korea Port Economic Association
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• v.24 no.4
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• pp.349-361
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• 2008

There has been abundant empirical research undertaken on the technical efficiency of Korean ports. Most studies have focused on the use of parametric and non-parametric techniques to analyse overall technical efficiency. This paper utilizes data for the period 2000-07 to offer a heterogeneous perspective on the overall efficiency of Korean ports. The framework assumes that ports use one input to produce one output; the output and input include port export(import) and regional export(import). This paper also employs panel analysis and heteroscedastic Tobit model to show the effect of the explanatory variables on the port efficiencies. The panel analysis shows that the regional export/total export has negative effect on the export efficiency while the regional import/total import has not any relations with the import efficiency. The heteroskedastic Tobit model shows that both regional export ratio and regional import ratio have negative effects on the efficiency while the gross regional domestic product has not any significant relations with the import efficiency.