• Journal of Korean Society of Water and Wastewater
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• v.29 no.3
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• pp.395-406
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• 2015

This research carried out an analysis on input cost and leakage reduction effect by leakage reduction method, focusing on the project for establishing an optimal water pipe network management system in the Taebaek region, which has been executed annually since 2009. Based on the result, optimal cost-benefit analysis models for water distribution network rehabilitation project were developed using DEA(data envelopment analysis) and multiple regression analysis, which have been widely utilized for efficiency analysis in public and other projects. DEA and multiple regression analysis were carried out by applying 4 analytical methods involving different ratios and costs. The result showed that the models involving the analytical methods 2 and 4 were of low significance (which therefore were excluded), and only the models involving the analytical methods 1 and 3 were suitable. From the result it was judged that the leakage management method to be executed with the highest priority for the improvement of revenue water ratio was installation of pressure reduction valve, followed by replacement of water distribution pipe, replacement of water supply pipe, and then leakage detection and repair; and that the execution of leakage management methods in this order would be most economical. In addition, replacement of water meter was also shown to be necessary in case there were a large number of defective water meters.

• Journal of Korea Water Resources Association
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• v.53 no.spc1
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• pp.731-742
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• 2020

The purpose of this study was to examine the efficiency of local waters in Chungnam. The Statistics of Waterworks data released by the Ministry of Environment were analyzed by DEA (Data Envelopment Analysis). DEA is a relatively data oriented approach to evaluate the performance of a set of peer entities called decision making units which convert multiple inputs into multiple outputs. It was possible to obtain significant results on the regional efficiency of local waters in 15 regional, the causes and degree of their inefficiency and what areas one could refer to. It was evaluated that the efficiency of Gun regional was insufficient, and it was found that an improvement policy was needed to improve productivity. This study provided implications for entire local waters operation in Chungnam.

• The Journal of the Korea Contents Association
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• v.10 no.12
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• pp.290-299
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• 2010

This study aims to evaluate the efficiency of superior appraisal corporations using DEA(Data Envelopment Analysis). DEA is known as a method for evaluating relative efficiency of organizations with multiple inputs and outputs. We used CCR-O and BCC-O DEA models to evaluate relative efficiency of superior appraisal corporations. Input variable is number of appraisers, output variables are total sales and net income. Total of 13 appraisal corporations in Korea were selected for this study, and the data were collected from financial reports for 2008 fiscal year. The result of this study is summarized as follows. First, the average of superior appraisal corporation's technical efficiency score is about 88.3% by applying CCR-O model. Second, the average of superior appraisal corporation's pure technical efficiency score is about 90% and scale efficiency score is about 98.2% by applying BCC-O model. According to the result of DEA, the cause of inefficiency is pure technical efficiency.

• Journal of Korea Technology Innovation Society
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• v.15 no.2
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• pp.400-420
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• 2012

This study explores the way to enhance research performance focusing basic and fundamental technology when researchers conduct international joint research with counterparts in foreign countries, funded under the National R&D programs. In order to retain validity and objectivity, mixed approaches including qualitative and quantitative are adapted at the first step. Through this step, main factors affecting the research performance can be addressed, such as the number of SCI papers published, conference attendance held both in domestic and foreign countries, researchers holding PhD involving in projects. Then, at the second step, DEA methodology is applied to explore the way to enhance research performance, based on the analysis at first step. The result at second step shows that the various ways can be drawn according to programs respectively and the general assumption of research funds and number of projects affecting positive outcome is not absolutely mentioned. Therefore, this study implies that input variables including research funds are not compatible with research performance in terms of international joint research and suggests further that the decisive outcome and management be reconsidered according to the programs respectively under the national R&D program.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.3
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• pp.61-71
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• 2018

The purpose of this study is to analyze the efficiencies of project management offices in large information system construction projects using the data envelopment analysis. In addition, we tried to estimate the confidence interval of those efficiencies using bootstrap DEA to give a statistical meaning. The efficiency by the CCR model is analyzed as eight project management offices are fully efficient and 22 project management offices are inefficient. On the other hand, there are 15 project management offices are fully efficient, but 15 project management offices are inefficient in the BCC model. As the result of the scale efficiencies, of the inefficient project management offices, 13 project management offices are inefficient in scale. It is possible to eliminate the inefficiency in the CCR model by improving their project performances. And, the nine project management offices showed that the inefficiency was due to pure technical efficiency, and these companies should look for various improvements such as improvement of project execution system and project management process. In order that the inefficient project management offices be efficient, it is analyzed that more efforts must be made for on-budget and on-time as a result of examining the potential improvement potentials of inefficient project management offices.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.3
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• pp.53-60
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• 2020

Evaluating the operational efficiency of electric vehicle charging stations (EVCSs) is important to understand charging network evolution and the charging behavior of electric vehicle users. However, aggregation of efficiency performance metrics poses a significant challenge to practitioners and researchers. In general, the operational efficiency of EVCSs can be measured as a complicated function of various factors with multiple criteria. Such a complex aspect of managing EVCSs becomes one of the challenging issues to measure their operational efficiency. Considering the difficulty in the efficiency measurement, this paper suggests a way to measure the operational efficiency of EVCSs based on data envelopment analysis (DEA). The DEA model is formulated as constant returns of output-oriented model with five types of inputs, four of them are the numbers of floating population and nearby charging stations, distance of nearby charging stations and traffic volume as desirable inputs and the other is the traffic speed in congestion as undesirable one. Meanwhile, the output is given by the charging frequency of EVCSs in a day. Using real-world data obtained from reliable sources, we suggest operational efficiencies of EVCSs in Seoul and discuss implications on the development of electric vehicle charging network. The result of efficiency measurement shows that most of EVCSs in Seoul are inefficient, while some districts (Nowon-gu, Dongdaemun-gu, Dongjak-gu, Songpa-gu, Guro-gu) have relatively more efficient EVCSs than the others.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.22 no.4
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• pp.301-315
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• 2011

DEA(Data Envelopment Analysis) is useful to measure the relative efficiency of organizational units where the presence of multiple inputs and outputs. This study applied DEA-CCR and DEA-BCC to evaluate the technical, pure technical, and scale efficiency of 29 university libraries. The input variables were number of books, print edition expenses, building space, staff, number of seats. As output variables we estimated: reader visits, number of borrowed items, number of visitors. It was found out that number of libraries with 100% relative efficiency among 29 libraries were 13. Also the results shows that main reason of inefficiency was from scale rather than from pure technical. Many inefficient libraries were operations of increasing return to scale.

• The Journal of Korean Academic Society of Nursing Education
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• v.26 no.4
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• pp.374-382
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• 2020

Purpose: The purpose of this study was to describe the profile of graduates from accelerated second-degree Bachelor of Science in Nursing programs and to analyze the relative efficiency of nursing colleges using data envelopment analysis. Methods: An online survey link was emailed to the deans of nursing colleges, who were then asked to send the link to graduates of the respective colleges. The survey questionnaire included demographics, reasons for applying to the accelerated second-degree Bachelor of Science in Nursing program, employment after graduation, and nursing career satisfaction. Results: Sixty-two graduates of the accelerated second-degree Bachelor of Science in Nursing program responded to the survey. The mean age at admission was 24.28 (± 3.01) years. Reasons for applying to the accelerated second-degree Bachelor of Science in Nursing program were primarily increasing job security and using it as a stepping stone to another career. Nursing career job satisfaction was 4.81 (± 1.07) and more than 82% recommended this program. The data envelopment analysis found the average efficiency score to be 0.84 (± 0.20) and 4 nursing colleges to be relatively efficient. Conclusion: The accelerated second-degree Bachelor of Science in Nursing program can be considered to be an effective means to produce quality nurses with non-nursing bachelor degrees in a short time; however, outcomes of this program need to be systematically monitored to maintain quality level. Through this, competent nurses with knowledge of adjacent studies will be added to the nursing workforce.

• Journal of Korea Port Economic Association
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• v.26 no.4
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• pp.219-246
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• 2010

Countries around the world are propelling policies and strategies to strengthen the competitiveness of their own ports as they recognize the roles and importance of the ports in the international trade and logistics. The main objective of this study is to compare efficiencies of major container ports and analyze the factors that affect the efficiencies in the three regions of East Asia, Europe, and North America, which cover most of world container shipping. We employ DEA models in analyzing the efficiencies of 45 container ports using 5 input and 2 output variables. We also carry out regression analyses to estimate the impacts of each factor on the throughput (TEU), overall technical efficiency (OTE), pure technical efficiency (PTE), and scale efficiency (SE). The analysis results show that East Asian ports, despite being smaller in average size, make greater output and achieve higher technical and scale efficiencies than European or North American ports.

• Journal of the Korea Society of Computer and Information
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• v.19 no.2
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• pp.21-30
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• 2014

The use of induction motors has been recently increasing in a variety of industrial sites, and they play a significant role. This has motivated that many researchers have studied on developing fault detection and classification systems of induction motors in order to reduce economical damage caused by their faults. To early identify induction motor faults, this paper effectively estimates spectral envelopes of each induction motor fault by utilizing a linear prediction coding (LPC) analysis technique and an expectation maximization (EM) algorithm. Moreover, this paper classifies induction motor faults into their corresponding categories by calculating Mahalanobis distance using the estimated spectral envelopes and finding the minimum distance. Experimental results show that the proposed approach yields higher classification accuracies than the state-of-the-art conventional approach for both noiseless and noisy environments for identifying the induction motor faults.