• 품질경영학회지
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• 제37권1호
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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.

• 유통과학연구
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• 제12권8호
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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.

• 한국산학기술학회논문지
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• 제11권6호
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• pp.2129-2137
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• 2010

본 연구는 경상남도 20개 보건소의 효율성을 평가하고, 비효율 보건소의 개선 목표치를 제시함으로써 효율성 제고에 실질적인 도움을 주고자 하였다. 효율성 평가방법으로는 자료포락분석(Data Envelopment Analysis: DEA)의 CCR, BCC 모형을 이용하여 보건소의 전체적 효율성과 사업 영역별 효율성을 평가하였다. 이를 위하여 투입변수로는 인력(의료직, 간호직, 보건직, 사무직)을 선정하였고 산출변수로는 보건소 사업(진료, 보건교육, 구강보건, 예방접종, 노인보건, 모자보건)을 선정하였다. 본 연구 결과는 기술효율성(TE) 평균은 0.868이었으며, 12개(60%) 보건소가 효율적으로 나타났다. 순수기술효율성(PTE)의 평균은 0.924이었으며, 14개(70%) 보건소가 효율적인 것으로 나타났다. 그리고 규모의 효율성(SE)의 평균은 0.933이었으며, 12개(60%)가 효율적인 것으로 나타났다. 위 연구결과를 토대로 보건사업의 체계적인 기획, 수행 및 평가를 통해 보건소가 효율적으로 운영되고 지역민에게는 최상의 의료서비스를 제공하기 위한 노력이 필요하다.

• Journal of Power Electronics
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• 제17권1호
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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.

• 한국유체기계학회 논문집
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• 제11권6호
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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.

• 국제초고층학회논문집
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• 제5권3호
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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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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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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.

• 대한설비공학회지:설비저널
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• 제5권2호
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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.

• 한국병원경영학회지
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• 제24권4호
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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.

• 한국항만경제학회지
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• 제24권4호
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• pp.349-361
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• 2008

국내 항만 간 수출입 물동량 처리실적은 지속적으로 변화하고 있다. 수출에서는 부산항의 비중이 크고 빠르게 감소함과 더불어 국내 여타 항만들의 비중이 증가하고 있으며, 수입에서는 인천항의 비중이 빠르게 높아지고 있다. 이에 본고는 DEA모형을 이용하여 도출한 국내 항만의 수출효율성과 수입효율성을 종속변수로 하여 패널분석을 한다. 또한 패널 분석의 단점을 보완하기 위하여 효율성 척도를 종속변수로 하여 이분산 토빗모형을 적용한다. 먼저 모형을 설정하고 모형의 안정성을 담보한 후 패널분석을 실시하여 고정계수모형과 확률계수모형에 관계없이 항만수출비중은 음의 부호로 유의하나 항만수입비중은 유의하지 않다는 것과 지역수출비중은 음의 부호로 유의하나 지역수입비중은 효율성과 유의한 관계를 갖지 않는다는 것을 보인다. 규모더미변수를 투입하여 부산항을 제외한 광양항, 평택항, 인천항, 울산항과 같은 대규모 항만의 효율성이 목포항과 군산항과 같은 소규모 항만의 효율성보다 높지 않다는 것도 밝힌다. 이분산성을 고려한 type II 토빗모형을 적용하여 지역의 수출은 효율성에 부정적 영향을 미치는데 비해 지역항만의 수출은 긍정적 영향을 미치며, 지역내총생산은 수출효율성에 별다른 영향을 미치지 않는다는 것을 보인다. 이러한 결과를 통해 배후단지 조성과 항만의 효율성이 동의어가 아니라는 것도 보인다.