• 제목/요약/키워드: VRS model

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시계열 UAV 영상을 활용한 연안지역 침식·퇴적 변화 모니터링 (Erosion and Sedimentation Monitoring of Coastal Region using Time Series UAV Image)

  • 조기성;현재혁;이근상
    • 한국지리정보학회지
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    • 제23권2호
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    • pp.95-105
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    • 2020
  • 효율적인 연안관리 업무를 추진하기 위해서는 다양한 요인에 의해 변화하는 지형의 특성을 지속적으로 모니터링하는 것이 중요하다. 본 연구에서는 격포해수욕장을 대상으로 시계열 UAV 영상을 촬영하였으며, UAV 위치정확도 평가를 위해 VRS 측량성과와 비교한 결과 ±11cm(X), ±10cm(Y), ±15cm(Z)의 표준편차를 얻었으며 따라서 수치지도 작업규정상의 허용오차를 만족하는 것으로 확인되었다. 또한 UAV 영상을 통해 구축한 수치표면모델을 이용하여 침식 및 퇴적 변화 모니터링을 실시한 결과 2018년 6월과 2018년 12월 사이에는 평균 0.01m의 퇴적이 발생하였으며, 2018년 12월과 2019년 6월 사이에는 0.03m의 침식이 발생된 것으로 분석되었다. 따라서 2018년 6월과 2019년 6월 사이에는 전체적으로 0.02m의 침식이 발생된 것을 알 수 있었다. 그리고 시계열로 분석한 지형변화 모니터링 결과로부터 침식 및 퇴적 높이 구간별 면적을 분석한 결과 ±0.5m 구간에서 침식과 퇴적면적이 가장 넓게 분포함을 알 수 있었다. 본 연구에서 제시한 시계열적 UAV 영상을 이용한 3차원 지형 모델링 성과를 활용하여 해안지역의 지형변화를 지속적으로 모니터링 한다면 양빈이나 준설 등과 같은 연안관리 업무를 보다 효과적으로 지원할 수 있을 것이다.

국가별 의료서비스의 운영효율성과 품질효율성 비교: OECD 회원국들을 중심으로 (Comparison of Operational Efficiency and Quality Efficiency of Medical Services by Country : Focused on OECD Member Countries)

  • 김현정;손지윤
    • 서비스연구
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    • 제11권4호
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    • pp.43-55
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    • 2021
  • 본 연구는 OECD 회원국들을 대상으로 의료서비스의 운영효율성과 품질효율성을 비교 분석하였다. 이를 위하여 2017~2019년의 OECD 보건통계(Health Statistics) 자료를 이용하였다. 분석 방법으로는 산출지향형(output-oriented) 규모수익가변(VRS: Variable Returns to Scale) 모형을 적용하여 초효율성(super efficiency)을 측정하였다. 분석결과, 운영효율성의 상위 그룹에는 스위스, 한국, 이탈리아, 노르웨이, 오스트리아, 네덜란드, 중위 그룹에는 캐나다, 그리스, 덴마크, 멕시코, 미국, 영국, 체코, 프랑스, 핀란드, 헝가리, 호주, 하위 그룹에는 벨기에, 독일, 스페인이 포함되었다. 품질효율성의 상위 그룹에는 노르웨이, 스위스, 스페인, 중위 그룹에는 그리스, 덴마크, 멕시코, 미국, 영국, 캐나다, 프랑스, 핀란드, 헝가리, 호주, 하위 그룹에는 네덜란드, 독일, 벨기에, 오스트리아, 이탈리아, 체코, 한국이 해당되었다. 2018년을 기준으로 OECD 회원국별로 효율성을 비교 분석한 결과, 운영효율성이 가장 효율적인 한국은 품질효율성이 비효율적이었다. 한국(0.998)은 그리스(0.422), 스위스(0.207), 스페인(0.371)을 벤치마킹하여 기대수명을 0.2(0.2%), 주관적 건강 인지를 44.2(138.1%)씩 개선하여 품질효율성을 향상시켜야 한다. 이는 국내에서 기대수명이나 유병률 같은 객관적 지표로 건강상태를 측정하고 있지만, 의학적 진단 여부와 별개로 국민들이 본인의 건강에 관하여 주관적으로 평가하는 것을 관리할 필요가 있음을 의미한다. 본 연구는 운영효율성에 초점을 맞춘 대부분의 선행연구들과 다르게 운영효율성과 품질효율성을 함께 측정했다는 점에서 학술적인 시사점을 지닌다. 또한 OECD 회원국별 의료서비스 산업의 효율성을 비교 분석함으로써, 국내 의료서비스 산업의 국제적인 경쟁력 수준을 확인하고 효율성 개선 방안을 제시했다는 점에서 실무적인 시사점을 지닌다.

국립대학교병원의 DEA 효율성과 경영성과 간의 관계 (Relationship between DEA Efficiency and Management Performance of National University Hospitals)

  • 하오현;정우식;정용모
    • 보건의료산업학회지
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    • 제9권1호
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    • pp.17-29
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    • 2015
  • This study, an examination of the plan for effective resource management for national university hospitals, was performed to determine the relationship between the effectiveness of patient output by considering input personnel using the DEA model and Management Performance, in which 4 years of data from 12 national university hospitals were analyzed. Among the components of the effectiveness, utilizing properly imput components from the application of VRS(Variable Returns to Scale), the Management Performance of national university hospitals was found to be affirmatively influenced by PTE(Pure Technical Efficiency). Regarding the Management Performance of national university hospitals in their attempts to establish a plan for effective human resource management, the management of patient numbers on the basis of calculation level with input is more recommendable than the controlling of personnel input using patient numbers. Thus, the establishment of a strategy plan for the proper allocation of administrative staff and sickbeds, considering the variation of patient numbers, is suggested.

양식업의 양식방법별 어종별 생산효율성 비교분석에 관한 연구 (The Study on the Comparative Analysis of the Aquaculture Production Efficiency Regarding Methods and Species)

  • 박철형
    • 수산경영론집
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    • 제43권2호
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    • pp.79-94
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    • 2012
  • The purpose of this study is to investigate the production efficiencies of the Korean aquaculture fishery with respect to species and methods using a Data Envelopment Analysis. The study extracted the 8 fishes in each of the sea cage culture, aquarium basin, and enclosed aquaculture for the analytical purposes. First, the study estimated the technical, pure technical, and scale efficiencies of the total of 24 aquaculture fishes based on the traditional DEA under the assumptions of both CRS and VRS. 2 fishes were identified as the efficient DMUs under the CCR-model, and 6 fishes under the BCC-model. Second, we tested to see if there was any difference in production efficiencies regarding those three different methods of aquaculture. we could not find any evidence of the differences in efficiency using a rank sum test based on the traditional DEA. However, we could do find that the pure technical efficiency in the sea cage culture was lower than others at 1% level of significance and the pure technical efficiency in enclosed aquaculture was also lower than others at 5% level of significance using Bilateral-DEA, which could explicitly consider the heterogeneity in the 3 production methods of aquaculture. Finally, the study obtained the 95% confidence intervals of the efficiency scores for the 24 fishes under our study using the smoothed bootstraping method in the process of the re-sampling in cooperation with both a kernel density estimation and a reflection method. At the same time, we could estimate the bias-corrected efficiency scores while the traditionally estimated efficiency scores suffered from the biases in the process of solving a linear programming with the deterministic nature of a production frontier. And hence, we could distinguish the differences in production efficiencies of the 8 fishes with respect to those 3 methods of aquaculture.

피부의 특성 추출을 위한 가시광선 반사 스펙트럼의 역 추적 최적화 알고리즘 개선 (Impmvement of Inverse Fitting Algorinlm of Visible Reflectance Spectrum to Extract Skin Parameters)

  • 최승호;임창환;정병조
    • 한국광학회지
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    • 제18권3호
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    • pp.179-184
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    • 2007
  • 본 논문은 가시광선 반사 스펙트럼으로부터 피부조직의 광학적, 구조적 특성을 역 추출하는 알고리즘에 대한 연구를 다룬다. 본 연구에서는 유전알고리즘을 사용한 기존의 역 추적 최적화 알고리즘에 파장 선택법과 심플렉스법을 추가하여 알고리즘의 최적화 능력을 개선하였다. 파장 선택법은 기존 알고리즘에 사용된 135개의 파장 중 10개의 유효 파장만을 사용한 결과 계산시간이 83% 감소하였다. 심플렉스법을 사용해 유전알고리즘으로 얻은 근사적인 탐색 점으로부터 재 탐색을 수행하였고, 이를 통해 얻은 탐색 점의 SSE(sum of square error)는 기존 유전알고리즘 만으로 얻은 탐색 점이 가지는 SSE의 0.64%였다. 본 연구의 모델링 결과를 통해 개선된 알고리즘이 기존 알고리즘에 비해 빠르고 정확한 해를 찾는다는 것을 확인할 수 있었다.

DEA 모형을 이용한 TV홈쇼핑기업의 상대적 효율성 연구 (Efficiency Analysis for TV Home Shopping Companies Using DEA(Data Envelopment Analysis))

  • 김순홍;안영효;오승철
    • 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.

Performance of Drip Irrigation System in Banana Cultuivation - Data Envelopment Analysis Approach

  • Kumar, K. Nirmal Ravi;Kumar, M. Suresh
    • Agribusiness and Information Management
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    • 제8권1호
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    • pp.17-26
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    • 2016
  • India is largest producer of banana in the world producing 29.72 million tonnes from an area of 0.803 million ha with a productivity of 35.7 MT ha-1 and accounted for 15.48 and 27.01 per cent of the world's area and production respectively (www.nhb.gov.in). In India, Tamil Nadu leads other states both in terms of area and production followed by Maharashtra, Gujarat and Andhra Pradesh. In Rayalaseema region of Andhra Pradesh, Kurnool district had special reputation in the cultivation of banana in an area of 5765 hectares with an annual production of 2.01 lakh tonnes in the year 2012-13 and hence, it was purposively chosen for the study. On $23^{rd}$ November 2003, the Government of Andhra Pradesh has commenced a comprehensive project called 'Andhra Pradesh Micro Irrigation Project (APMIP)', first of its kind in the world so as to promote water use efficiency. APMIP is offering 100 per cent of subsidy in case of SC, ST and 90 per cent in case of other categories of farmers up to 5.0 acres of land. In case of acreage between 5-10 acres, 70 per cent subsidy and acreage above 10, 50 per cent of subsidy is given to the farmer beneficiaries. The sampling frame consists of Kurnool district, two mandals, four villages and 180 sample farmers comprising of 60 farmers each from Marginal (<1ha), Small (1-2ha) and Other (>2ha) categories. A well structured pre-tested schedule was employed to collect the requisite information pertaining to the performance of drip irrigation among the sample farmers and Data Envelopment Analysis (DEA) model was employed to analyze the performance of drip irrigation in banana farms. The performance of drip irrigation was assessed based on the parameters like: Land Development Works (LDW), Fertigation costs (FC), Volume of water supplied (VWS), Annual maintenance costs of drip irrigation (AMC), Economic Status of the farmer (ES), Crop Productivity (CP) etc. The first four parameters are considered as inputs and last two as outputs for DEA modelling purposes. The findings revealed that, the number of farms operating at CRS are more in number in other farms (46.66%) followed by marginal (45%) and small farms (28.33%). Similarly, regarding the number of farmers operating at VRS, the other farms are again more in number with 61.66 per cent followed by marginal (53.33%) and small farms (35%). With reference to scale efficiency, marginal farms dominate the scenario with 57 per cent followed by others (55%) and small farms (50%). At pooled level, 26.11 per cent of the farms are being operated at CRS with an average technical efficiency score of 0.6138 i.e., 47 out of 180 farms. Nearly 40 per cent of the farmers at pooled level are being operated at VRS with an average technical efficiency score of 0.7241. As regards to scale efficiency, nearly 52 per cent of the farmers (94 out of 180 farmers) at pooled level, either performed at the optimum scale or were close to the optimum scale (farms having scale efficiency values equal to or more than 0.90). Majority of the farms (39.44%) are operating at IRS and only 29 per cent of the farmers are operating at DRS. This signifies that, more resources should be provided to these farms operating at IRS and the same should be decreased towards the farms operating at DRS. Nearly 32 per cent of the farms are operating at CRS indicating efficient utilization of resources. Log linear regression model was used to analyze the major determinants of input use efficiency in banana farms. The input variables considered under DEA model were again considered as influential factors for the CRS obtained for the three categories of farmers. Volume of water supplied ($X_1$) and fertigation cost ($X_2$) are the major determinants of banana farms across all the farmer categories and even at pooled level. In view of their positive influence on the CRS, it is essential to strengthen modern irrigation infrastructure like drip irrigation and offer more fertilizer subsidies to the farmer to enhance the crop production on cost-effective basis in Kurnool district of Andhra Pradesh, India. This study further suggests that, the present era of Information Technology will help the irrigation management in the context of generating new techniques, extension, adoption and information. It will also guide the farmers in irrigation scheduling and quantifying the irrigation water requirements in accordance with the water availability in a particular season. So, it is high time for the Government of India to pay adequate attention towards the applications of 'Information and Communication Technology (ICT) and its applications in irrigation water management' for facilitating the deployment of Decision Supports Systems (DSSs) at various levels of planning and management of water resources in the country.

일부 월경통(月經通) 환자의 스트레스 반응 척도와 심박변이도상의 특징 고찰 (Analysis on the Stress Response Inventory and Heart Rate Variability of Dysmenorrhoea Patients)

  • 이지영;이진무;이창훈;조정훈;장준복;이경섭
    • 대한한방부인과학회지
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    • 제21권1호
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    • pp.216-230
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    • 2008
  • Purpose: The purpose of this study is to analysis on the Stress Response Inventory(SRI) and Heart Rate Variability (HRV) of some dysmenorrhoea patients. Methods: We studied 34 patients visiting OO Medical Center from May 2007 to November 2007. And the severity of dysmenorrhoea were measured by Multidimensional Verbal Rating scale(MVRS), Verbal Rating scale (VRS) and Visual Analog Scale(VAS). And SRI and HRV were recorded. Results: According to comparison of Means of HRV values among the groups, most of them were not statistically significant. But the comparison of Means of SRI, the points of almost all values were kept by order of Severe-Moderate-Mild-None group. Most of them are statistically significant. According to correlation analysis between dysmenorrhoea scale and HRV, most of them were not statistically significant. But the correlation analysis between HRV and SRI, there were some correlations. And the correlation analysis between SRI and dysmenorrhoea scale, most of them were statistically significant. According to General Linear Model of Dysmenorrhoea $scale^{\ast}SRI$ and HRV. Dysmenorrhoea scale and SRI influenced values of HRV. But it is hard to conclude the relationship between Dysmenorrhoea $scale^{\ast}SRI$ and HRV Conclusion: The results suggest that stress is related to dysmenorrhoea. But the relation between dysmenorrhoea and HRV was hard to conclude. We need more study for settling the relation between dysmenorrhoea and HRV.

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연안지형 변화 탐지를 위한 UAV 활용기술 (UAV Application Technology for Detection of Coastal Topography)

  • 이근상;김영주;최연웅
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2022년도 학술발표회
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    • pp.445-445
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    • 2022
  • 최근 새만금 방조제 건설이 완료됨에 따라 주변 연안지역의 지형에 많은 변화가 감지되었다. 본 연구대상지는 격포해수욕장으로서 새만금 사업 준공 후 연안침식에 따른 모래 유실 등으로 인해 양빈사업 등이 검토되고 있는 상황이다. 본 연구에서는 연안지형 변화 탐지를 위한 UAV (Unmanned Aerial Vehicle) 활용기술을 제시하는 것으로서 총 3회에 걸쳐 UAV 영상을 촬영하였다. 영상촬영은 DJI Inspire 2 UAV를 활용하였으며 VRS(Virtual Reference Service) 측량성과와 연계하여 Pix4D Mapper SW를 통해 정사영상과 수치표면모델(DSM; Digital Surface Model)을 제작하였다. 먼저 2018. 6. 29 ~ 2018. 12. 10 사이의 지형변화 탐지를 수행한 결과 침식과 퇴적의 최대값은 각각 2.56m와 2.24m로 나타났으며 평균적으로는 0.01m의 퇴적이 발생하였다. 그리고 2018. 6. 29 ~ 2019. 6. 14 동안의 침식과 퇴적의 최대값은 각각 2.31m와 2.28m로 나타났으며 평균값은 0.02m의 침식이 발생하였다. 또한 2018. 12. 10 ~ 2019. 6. 14 사이에는 침식과 퇴적의 최대값이 각각 2.28m와 2.55m로 나타났으며 평균값은 0.03m의 침식이 발생하였다. 지형변화를 보다 상세히 모니터링하고자 퇴적과 침식구간을 나누어 분석을 수행한 결과, 2018. 6. 29 ~ 2018. 12. 10 사이에는 0.5m 이내의 침식과 퇴적구간 면적이 각각 13,324.4m2와 14,667.3m2로 퇴적구간의 면적이 1,342.9m2 만큼 높게 나타났으며, 2018. 12. 10 ~ 2019. 6. 14 사이에는 0.5m 이내의 침식과 퇴적구간 면적이 각각 16,176.6m2와 11,723.0m2로 침식구간의 면적이 4,453m2 만큼 높게 나타났다. 또한 2018. 12. 10 ~ 2019. 6. 14 사이에는 0.5m 이내의 침식과 퇴적구간 면적이 각각 16,821.6m2와 11,126.4m2로 침식구간의 면적이 5,695.2m2 만큼 크게 분석되었다. 이와 같이 UAV 영상 기반의 연안지형 모니터링을 수행할 경우 시계열 지형변화를 효과적으로 모니터링할 수 있으며, 이러한 업무는 새만금 방조제 건설에 따른 지형변화의 영향평가 등 다양한 연안업무에 활용될 수 있을 것이다.

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소매유통업의 효율성 분석에 관한 연구 (An analysis of retail business efficiency in Korea)

  • 김순홍;유병국
    • 유통과학연구
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    • 제12권4호
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    • pp.23-30
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    • 2014
  • Purpose - The purpose of this study is to analyze the efficiency of retail businesses by dividing domestic retailers into discount stores, super supermarkets (SSMs), and department stores. It suggests retail-business investment strategies by using data environment analysis (DEA) to analyze how input elements such as store area, parking lot area, number of employees, and sales management expenses for the convenience of customers positively affect business performance measurements such as sales and visiting customers per day. Research Design, Data, and Methodology - The DEA model calculates a ratio of the weighted mean of various inputs to the weighted mean of various outputs and measures the efficiency of a specific decision making unit (DMU). The study included 19 companies (five discount store DMUs, ten SSM DMUs, and four department store DMUs). Because the business elements and sizes of retail store DMUs used in this analysis are different, average per-store input and output variables were used. Data were collected from "The Yearbook of Retail Industry in Korea (2012)." DEA analysis was used to determine differences in efficiency among discount stores, SSMs, and department stores in terms of the business elements of each retail business. It was also used to determine what business elements were excessively invested in by comparing and analyzing efficiency by business elements using SPSS software's ANOVA (Analysis of Variance). Results - The CCR and BCC efficiency analysis found that the efficiency of discount stores is low. We believe that the saturation state of discount stores is a major factor. The ANOVA analysis confirms the VRS hypothesis with a statistically significant difference among the three groups, based on an analysis confidence interval of 95%. CRS and SE were not found to be significantly different among the three groups. As for the post hoc test, which concretely shows differences by group, the Scheffe's multiple comparison analysis test found the average differences between group 1 (discount stores) and group 2 (SSM) to be statistically significant. Conclusions - The DEA efficiency analysis implies that investment in input elements, including store area, parking lot area, and sales management expenses, were excessive in the case of discount stores, while SSMs need to invest more in promotion activities such as gifts, events, and coupons for customer management. Department stores have found that small companies invest excessively in input elements. Department stores need to invest in differentiated shopping mall complexes. This study was limited in acquiring statistical data; various input variables which might have shown more secure customer management and promotional expenses could not be applied. As the study was limited in various aspects of the efficiency analyses because financial analyses of the companies and of causal relationships, including satisfaction and loyalty of visiting customers, were not done, these aspects will be examined in the next study.