• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.4
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• pp.208-215
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• 2013

An experimental study of an ORC (Organic Rankine Cycle) system has been performed for small-scale applications in the range of a few kW for low-grade-recovery heat sources. The ORC system was equipped with a scroll expander. Experimental tests were carried out using this system, and showed good performance and reliability for the small-scale system. The effects of various operating conditions were selected as the main parameters for the performance of ORC system, such as the expander speeds and mass flow rates of R-134a for expander inlet temperatures ranging from $100^{\circ}C$ to $190^{\circ}C$, as well as the thermal power, thermal efficiency, expansion efficiency, and volumetric efficiency.

• Journal of Korean Society for Quality Management
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• v.46 no.3
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• pp.707-716
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• 2018

Purpose: This study aims to analyze the management performance and production efficiency of strawberry farmers who introduced smart farming, one of the primary symbols of the fourth industrial revolution in the agricultural sector. Methods: We conducted an empirical survey of strawberry farms using smart farming and analyzed production efficiency using DEA method. Results: First, difficulties for strawberry farmers introducing smart farming included time and money spent on parts replacement and additional costs due to compatibility problems with existing facilities after the adoption. Second, strawberry farmers using smart farming increased their total income by producing higher yield and improving quality thanks to the competent growth management. Third, the analysis of production efficiencies before and after smart farming found improvement in technical efficiency, pure technical efficiency, and scale efficiency. But, the gaps in technical and scale efficiencies among the farms widened. Conclusion: Based on the results above, following policy suggestions are offered. First, an environment control technology suitable for strawberry farming needs to be developed. Second, the smart farming technology needs to be standardized by the government. Third, new smart farm models need to be developed to accommodate to the facilities and environment in Korea through collecting big data including high-quality data on the environment, growth, and yield. Fourth, continuing education needs to be provided to narrow the gap in smart farming technology among strawberry farmers.

• Journal of Korea Society of Waste Management
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• v.35 no.7
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• pp.600-605
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• 2018

In this study, the combustion characteristics were investigated based on the biodrying solid recovered fuel (SRF) in a 5 Ton/day scale combustion boiler. The composition of the combustion gas containing the biodrying SRF was analyzed, the particulate matter, and its HCl content was determined with the air pollutant process test method. Mass balance, carbon balance, and combustion efficiency were calculated according to the equivalence ratio (ER) method; the energy recovery efficiency of the combustion boiler was also analyzed. The overall combustion efficiency of the biodrying SRF was 97.3 % and the energy recovery efficiency was 80.2%.

• The Korean Journal of Franchise Management
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• v.6 no.1
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• pp.1-20
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• 2015

Home Meal Replacement (HMR) products are ready-to-eat or pre-cooked food products that are consumed at daily home. HMR market has grown rapidly due to societal changes: increases in female social activities, silver population, and one-person households. Consumption channels of HMR can be classified into take-out, delivery, and retail. In Korean HMR market, retail sector is largely growing, but companies are focusing their business on the home delivery sector. Moreover, franchise companies are expanding their areal coverage in the HMR market based on their multi-unit strategy. However, more research on the HMR market is needed as existing studies are limited in conceptualization, classification, and processed food from malls or home-shopping channels. Therefore, we conducted the efficiency analysis on Gukseonsaeng, one of franchises that applied the take-out channel, using DEA method. According to the research on 29 franchisees of Gukseonsaeng, 77.9% of input appeared inefficient for technical efficiency, while 53.3% of input appeared inefficient for scale efficiency. Thus, we found that franchises of Gukseonsaeng are structured in increasing returns to scale (IRS), so enhancing efficiency by expanding scales need to be implemented.

• Korea Journal of Hospital Management
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• v.16 no.4
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• pp.35-66
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• 2011

This study analyzed efficiency by utilizing DEA analytical technique centering on materials for 2009 of 20 major university hospitals in capital area. Input variables were utilized professor & full-time doctor, resident, nurse & number of bed hospitals. Output variables were analyzed by dividing number of annual outpatients & number of annual inpatients, and annually total outpatient profit & inpatient profit into a model of the standard for number of patients and the standard for medical profit. DEA analysis was elicited efficiency score by applying CCR, BCC, BFG, scale profit, and SE model. Through t-test after eliciting efficiency score, the implications were suggested by comparing efficiency between DMU in Seoul and DMU in capital area, by comparing between high-class general hospitals and general hospitals, and by comparing between high-class general hospitals in Seoul and 5 big hospitals. As a result of analysis, the major university hospitals in capital area showed high efficiency as a whole close to "1," but indicated low efficiency relatively in CCR field. Thus, the expansion in scale within capital area was indicated to reach the limit. Second, in a model of analyzing the standard for number of patients, the medical institutions, which are being operated efficiently, were indicated to be 10 DMUs. In the standard for medical profit, 12 DMUs were analyzed to be operated efficiently. Third, the efficiency in general hospital was higher than high-class general hospital. Thus, the efficiency of operation was indicated to be more important than scale. Also, large high-class hospitals(big 5) where are located in downtown Seoul showed the higher efficiency than other general high-class general hospitals, but were indicating very low efficiency in some DMUs. Fourth, as a result of generalizing and evaluating the number of patients and the medical profit, the efficient DMU was indicated to be more when analyzing on the basis of medical profit than the standard for number of patients. Thus, major university hospitals in capital area were indicated to make more effort for section in medical profit. Based on the analytical results of efficiency, a strategy for reinforcing efficiency in inefficient DMU was indicated to be needed a strategy of creating customers for promoting number of patients and a strategy for making operation efficient for increasing profitability.

• Journal of Korea Port Economic Association
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• v.38 no.1
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• pp.113-127
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• 2022

The purpose of this study is to analyze the efficiency of 90 domestic passenger shipping routes using the DEA Window model as a Decision Making Unit (DMU). Data from 2015 to 2019 are divided into three windows, and efficiency was analyzed by using the number of passenger ships of sails, gross tonnage and distance traveled as input variables and transportation performance of the general public and islanders as output variables. As a result of the analysis, improvements are derived and presented for routes with low relative efficiency. In particular, the efficiency is evaluated for general routes operated by private operators as profit routes and auxiliary routes supported by the government as non-profit routes. In addition, scale efficiency (SE) is derived by using the technical efficiency (TE) of the CCR model and the pure technical efficiency (PTE) values of the BCC model. It is found that the inefficiency of the route was due to pure technical efficiency (PTE) rather than scale efficiency (SE). It will be necessary to consider the improvements for each route shown in the analysis results of this study when establishing the policy for the domestic passenger shipping route.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.6
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• pp.640-647
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• 2006

It is difficult to treat wastewater involved in heavy metal in electroplating industry. Recently, many industries adopt the clean technology to prevent production of pollutant in the process or reuse after the appropriate pollutant treatment. In this study, we estimate the ability of recovery of nickel and the efficiency using lab-scale ion exchange and electrodialysis process with electroplating industry wastewater. In the ion exchange experiments with 5 types of resin, the result showed that S 1467(gel-type strong acidic cation exchange resin) has the highest exchange capacity. And it showed that the 4 N HCl has the highest in regeneration efficiency and maximum concentration in the regeneration experiments with various kinds md concentration of the regenerant. During the electrodialysis experiments, we varied the current density, the concentration of electrode rinse solution, the flow rate of concentrate and electrode rinse solution in order to find the optimum operating condition. As a result, we obtained $250A/m^2$ of current density, 2 N $H_2SO_4$ of concentration of electrode rinse solution, 30 mL/min of flow rate of concentrate and electrode rinse solution as the best operating conditions. We performed the scale-up experiments on the basis of ion exchange and electrodialysis experiments. And we obtained the experimental result that exchange capacity of S 1467 was 1.88 eq/L resin, and regeneration efficiency was 93.7% in the ion exchange scale-up experiment, we also got the result that concentration and dilution efficiency increased, and current efficiency kept constant in the scale-up experiments.

• Journal of Korean Society for Quality Management
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• v.49 no.2
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• pp.213-231
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• 2021

Purpose: This study intends to provide decision-making information to improve efficiency by analyzing the management efficiency of smart greenhouse business entities and identifying factors that affect the efficiency based on input and output. Methods: The subjects of analysis were business entities for cultivating strawberries in smart greenhouses in Jeolla region (northern and southern Jeolla provinces), and the analysis focused on the management performance of the 2019-2020 crop period (year). Data Envelopment Analysis(DEA) was applied as an analysis method for efficiency analysis, Quantile Regression(QR) analysis was applied as a factor affecting the efficiency. Results: The reason for the efficiency gap between business entities was that there were many business entities that did not minimize the input cost at the current level of output, and the area where the variance among business entities was large was the fixed cost per 10a. In the results of the affecting factor analysis, it was found that the seed-seedlings cost, fertilizer cost, other material cost, and employment and labor cost had a negative (-) effect on the efficiency, and that the repair and maintenance cost had a positive (+) effect. Conclusion: Therefore, to achieve the efficiency of scale, it is necessary to reduce the input scale to an appropriate level. In the case of business entities with low efficiency by quartile, the seed-seedlings, fertilizer, and other material costs reduce expenditures, and repair maintenance costs can improve efficiency by increasing expenditures.

• Journal of Wetlands Research
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• v.13 no.2
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• pp.161-169
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• 2011

The objective of this study was to evaluate the efficiency of a modified filtration system treating non-point source (NPS) pollutants. The developed Best Management Practice (BMP) technology was designed based on the geographical and climatic characteristics of the site. A lab-scale test experiment was conducted using three different hydraulic loading rates representing the first flush flow, average flow and overflow conditions during a rainfall event. Water quality analysis was performed on the water samples taken at the inflow, outflow and infiltration during the test experiment of the lab-scale BMP. Also, the water and mass balance at different hydraulic loading rates was determined. Results from the lab-scale test experiment showed that the lab-scale BMP had a high removal efficiency of 80-90% for all NPS pollutants. The overflow test condition obtained the lowest removal efficiency among the hydraulic loading rates because it gave less opportunity for the pollutants to be filtered and retained inside system. The infiltration ratio was approximately 1 % of the inflow and outflow. Increasing the infiltration ratio requires technical approach of soil amendment where the BMP is installed.

• The Journal of the Korea Contents Association
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• v.20 no.4
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• pp.159-168
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• 2020

This study aims to utilize DEA, analyze the efficiency of Korean coffee franchises, look into the factors that affect efficiency, and improve the efficiency of Korean coffee franchises. The main results of this study are as follows. First, according to CCR model standards, there are a total of 9 efficient coffee franchises and according to BCC model standards, there are a total of 12 efficient coffee franchises. A total of three of the inefficient DMUs were found to have a value of 1 for BCC, while the other 25 were found to be inefficient for both technology and scale. Second, of 28 franchises, 11 were analyzed to be decreasing return to scale and through future increased investments of optimum levels, business performance can be improved and efficiency can be enhanced. Analysis showed that 9 franchises appeared as CRS and it is most ideal to maintain the yield of future output elements at current levels and the work efficiency of 8 franchises in increasing returns to scale states expands as production scales increase according to specialization and role division and yield can relatively improve a lot. Third, the analysis of factors affecting the efficiency of franchises through the Tobit regression analysis showed that the number of franchises and operating periods had a positive (+) effect on efficiency. Based on this study, the efficiency of coffee franchises should be analyzed to establish strategies to maximize efficiency. Based on this study, the efficiency of coffee franchises should be analyzed to establish strategies to maximize efficiency.