• Nuclear Engineering and Technology
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• v.52 no.11
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• pp.2601-2606
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• 2020

In this study, we expanded the performance of the existing EXVol code and performed empirical experiments and calculations. A high-resolution gamma spectroscopy system was constructed, and a standard point source and a standard volume source were measured with an HPGe detector with 43.1% relative efficiency. EXVol was verified by quantitative comparison of the detection efficiencies determined by measurements and calculations. To introduce the concept of the detector scanning that occurs in the actual measurement into the EXVol code, a collimator was placed between the source and detector. The detection efficiency was determined in the asymmetric arrangement of the source and detector with a collimator. A collimator made of lead with a diameter of 15 mm and a thickness of 50 mm was installed between the source and the detector to determine the detection efficiency at a specific location. The calculation result was contour plotted so that the distribution of detection efficiency could be visually confirmed. The relative deviation between the measurements and calculations for the coaxial and asymmetric structures was 10%, and that for the collimation structure was 20%. The results of this study can be applied to research using γ-ray measurements.

• The Research Journal of the Costume Culture
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• v.18 no.1
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• pp.13-28
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• 2010

This study is focused on the elucidation of efficient and correct marking methods by comparing and analyzing marker efficiency depending on the marking job condition such as interval of checking-pattern and marker orientation using woman's Jacket and Slacks. Research Method intended to compare the marking efficiency of Jacket and Slacks, check-less and check- patterned materials with the intervals of $1.5{\times}1.5cm$ and $5{\times}5cm$ were selected. First, in the comparison of marking efficiency depending on check-pattern interval, regardless of the direction of marker position, single-item makers and set-item makers, the efficiency of check-less materials was higher than those of check-patterned materials and increasing the intervals decreased marking efficiency and vice versa. Marking efficiency of Slacks was less influenced than marking efficiency of Jacket by check-pattern interval. Second, in the comparison of marking efficiency depending on the direction of marker position, regardless of check-pattern interval and number of maker pieces, the efficiency of nap-up-and-down position was higher than those of nap-one-way position. Third, the marking efficiency of single-item was more effective than one of set-item in all working condition except nap-one-way position in checkless materials.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.48 no.4
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• pp.322-336
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• 2012

To study the catching efficiency of biodegradable trammel net for swimming crab (Portunus trituberculatus), three types (biodegradable, monofilament and multifilament) of trammel nets were used in the field test, and the tests were carried out 16 times with two different mesh sizes (105mm and 160mm) in the Yeonpyeong fishing ground of Korea, 2009~2011. The catching efficiency of three type nets was analyzed by catch in number, catch in weight and average weight per individual of small and large size swimming crab by net types and mesh sizes. Statistical T-test was also carried out to verify the efficiency between the three types of nets. The results are as follows. The catch in number of swimming crab was 24,667 and formed about 81.0% of total catch. Of all swimming crab catch, small swimming crabs with less than 64mm in carapace length which is a prohibited landing size by law formed 48.1%, larger swimming crabs with more than 64mm in carapace length which is a landing size formed 51.9%. In 105mm mesh size trammel net test, the catch share in number of small size swimming crab by biodegradable trammel net was 47.5% in comparison with multifilament trammel net and 74.2% in comparison with monofilament trammel net, so biodegradable trammel net has more protective effects on small size swimming crab than other types of trammel nets. The protective effects for small size swimming crab by biodegradable trammel net was 25.8~52.5% in comparison with other types of trammel nets. The catch share in weight of large size swimming crab by biodegradable trammel net was 98.3% in comparison with multifilament trammel net and 92.3% in comparison with monofilament trammel net, so biodegradable trammel net has a similar catch efficiency to multifilament trammel net. The results of 160mm mesh size trammel net test have shown similar results of 105mm mesh size trammel net test. This study shows that biodegradable trammel net is a more useful fishing gear than multifilament and monofilament trammel net because biodegradable trammel net has lower catch rate than other types of nets in small size swimming crab and similar catch rate than multifilament trammel net which is a well used net by fishermen.

• Journal of the Korean Solar Energy Society
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• v.34 no.4
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• pp.51-56
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• 2014

In this paper, OTEC(Ocean Thermal Energy Conversion) system with vapor-vapor ejector is newly proposed. And 6 wet refrigerants are applied into the proposed OTEC system for performance comparison. The results of comparison performance are as follows. In the view of system efficiency, R32/R744(90:10) has the highest efficiency among the 6 refrigerants. In case of evaporation capacity, pump work and mass flow rate of working fluid, R744, R717 and R717 is lowest value, respectively. As this results, the vapor-vapor ejector is able to increase the efficiency of system. And It is necessary to select the optimized working fluid considering environmental and economic factors.

• Journal of Korea Port Economic Association
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• v.32 no.3
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• pp.1-20
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• 2016

The objective of this study was to select world top 20 major container terminals that belong to Korea and China as comparison units to analyze their efficiency and productivity trend. Super Efficiency Data Envelopment Analysis(SE-DEA) and Malmquist Productivity Index(MPI) models were applied to this study. Compared with previous studies, we narrowed down the scope of the comparison units to terminals and conducted more detailed analysis to present more meaningful implications to the actual operation. The different result from existing studies, SE-DEA analysis implied that the major terminals of Busan New Port showed similar efficiency and productivity with China's terminals. In MPI analysis, the average index of Korean and China's terminals is 1.051 and 1.049. The analysis indicates that the productivity was improved 5.1% and 4.9% annually. From 2012 to 2015, the average terminal TCI index of South Korea and China were 1.032 and 1.0318-the main factor which influences MPI. This means improving productivity mainly rely on investment in new equipment and technology upgrades rather than improve operational efficiency over the past few years. Future management decisions should consider more aggressive marketing to increase the volume and improve operational efficiency to enhance productivity. Further research should apply the overall efficiency of the methodology considering the financial diversification, terminal capacity, service levels, and other factors.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.19-19
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• 2011

The appraisals of hydrology model behavior for flow and water quality are generally performed through comparison of simulated data with observed ones. To perform appraisal of hydrology model, some criteria are often used, such as coefficient of determination ($R^2$), Nash and Sutcliffe model efficiency coefficient (NSE), index of agreement (d), modified forms of NSE and d, and relative efficiency criteria NSE and d. These criteria are used not only for hydrology model estimations also for various comparisons of two data sets; This NSE has been often used for SWAT calibration. However, it has been known that the NSE value has some limitations in evaluating hydrology at watersheds under monsoon climate because this statistic is largely affected by higher values in the data set. To overcome these limitations, the SWAT auto-calibration module was enhanced with K-means clustering and direct runoff/baseflow modules. However the NSE is still being used in this module to evaluate model performance. Therefore, the SWAT Auto-calibration module was modified to incorporate alternative efficiency criteria into the SWAT K-means/direct runoff-baseflow auto-calibration module. It is expected that this enhanced SWAT auto-calibration module will provide better calibration capability of SWAT model for all flow regime.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.357-358
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• 2015

This paper provides a comparison of power converter loss and thermal description for voltage source and current source type 5MW-class medium voltage topologies of wind turbines. Neutral-point clamped three-level converter is adopted for voltage source type topology while two-level converter is employed for current source type topology considering the popularity in the industry. In order to match the required voltage level of 4160V with the same switching device of IGCT as in voltage source converter, two active switches are connected in series for the case of current source converter. The loss analysis is confirmed through PLECS simulations. In addition, the loss factors due to di/dt and dv/dt snubber and ac input filter are presented. The comparison result shows that VSC-based wind turbine system has a higher efficiency than that of CSC under the rated operating conditions.

• International Journal of Quality Innovation
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• v.7 no.1
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• pp.90-97
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• 2006

The process of producing software differs in many aspects from that of traditional manufacturing. Software is not manufactured in the classical sense. Development of software more closely resembles the development effort that goes into design new product [1-3]. In this article, we first describe the foundations of process improvement, which all processes can share. The process improvement differences between software and manufacturing process are then discussed, and a defect driven process inspection and improvement is introduced. Based on the discussion, two experiments were designed and the results of the results were collected. Through the comparison, we found that some efficient quality improvement approaches can be easily adapted in the software improvement and that the inspection efficiency is also significant.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.2
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• pp.32-42
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• 2011

In this paper to compare the economical efficiency of light sources for a tunnel lighting, we define a model tunnel and design tunnel lighting. And to examine economical efficiency of various tunnel lightings we compare the lighting expenses of tunnels. The results shows high pressure sodium lamps are more economical than fluorescent lamps.

• Proceedings of the KAIS Fall Conference
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• 2007.05a
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• pp.112-115
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• 2007

Currently an increase in domestic sewage and industrial wastewater causes serious water pollution in Korea. To solve water pollution problems, conventional activated sludge (CAS) system is generally used in wastewater treatment plant but this process is so ineffective in nitrogen and phosphorus. Even if CAS system is the major process, it must be improved instantly so as to remove nitrogen and phosphorus. Otherwise, the serious water pollution problems can't be resolved with CAS system. Therefore this study focused on the comparison of the treatment characteristics between ASA system and CAS system. And also the mass balance of each process of ASA system. The results from operating advanced step aeration (ASA) system indicated that the removal efficiency of BOD, COD, and SS was 89.9%, 74.5%, and 89.0% respectively. In comparison, the removal efficiency of BOD, COD, and SS for CAS system was 89.5%, 71.8%, and 89.5% respectively. In addition to the results, the TN removal efficiency of ASA system was 76.5% comparing to 32.7% of CAS system. It was concluded that the TN removal efficiency of ASA system was 44% higher than CAS system. And the TP removal efficiency was 81.4% in ASA system comparing to 25.2% in CAS system. It also means that over 56% of TP was removed in ASA system comparing to CAS system.