• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.4
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• pp.341-351
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• 2013

Physical characteristics of PA (Polyamide) gill net and biodegradable gill net made by PBS (Polybutylene succinate) (mesh size 63mm, mesh thickness number 2, 2.5, 3) were analyzed to investigate catching efficiency of the biodegradable gill net for Pacific herring. Total 11 numbers of catching efficiency tests were carried out using commercial fishing vessel at Imwon port in Kangwon province from May to June 2013. The amount of catches were 1,535.7kg (18 species) through the catching efficiency tests and it is expected that the practicalization of biodegradable gillnet is possible because there is no difference for catches between PA gillnet and PBS gillnet. Catches of herring according to the thickness of net twine was the highest at No.2 and the thicker net twine tends to decrease the catches.

• Journal of Korea Multimedia Society
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• v.16 no.10
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• pp.1230-1237
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• 2013

Cyber lectures were expected to replace the traditional classroom lecture, yet they were criticized due to the inefficiency. With educational technology supplemented, cyber lectures have improved their efficiency through the coherence of superior planning ability and improvement in computer and network technology. This paper's purpose is to understand the factors that improve educational efficiency of cyber lectures. Cyber lecture for IT subject for software practice is created to test the educational efficiency as lecture on theories will not distinctively show the lecture efficiency. The survey was conducted to students and statistical analysis was done on collected data to analyze the factors that influence educational efficiency of created lecture.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.6
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• pp.604-611
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• 2012

For the commercialization of fuel cell powered vehicle, it is highly important to improve the performance and efficiency of an automotive polymer electrolyte membrane fuel cell (PEMFC) system. The performance and efficiency of PEMFC systems are significantly influenced by their operating conditions. Among these conditions, the system operating pressure is considered as the one of the main factors. In this study, to investigate the effects of operating pressure on the performance and efficiency of automotive PEMFC systems, two types of high-pressure operating PEMFC systems adopting two different compressors (i. e. different performance maps) are modeled by using MATLAB/Simulink environment. The PEMFC system efficiency and parasitic compressor power are mainly analyzed and compared for the two types of high-pressure operating PEMFC systems under the same system net power conditions. It is expected that this kind of study can contribute to provide basic insight into the operating strategies of high-pressure operating PEMFC systems for automotive use.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.31 no.1
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• pp.1-10
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• 2008

The enormous budget of government and manpower are invested to the government funded institutes every year. The R&D investment focused on input has to be turned toward the investment based on the effectiveness of R&D activities. Measuring the efficiency of research activities is required in order to evaluate the effectiveness of R&D investment in these institutes. The purpose of this paper is to evaluate the relative efficiency of research activities performed in 19 government funded research institutes. CCR/BCC model and DEA/AR model were applied to get the relative efficiency of 19 institutes. Assurance regions for the weight of output attributes were obtained by using the underlined concept of the analytic hierarchy process (AHP). We used input and output data items describing research activity of 19 government funded research institutes. The results of this study are expected to become a basis of the R&D investment decision of the government.

• 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.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.5
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• pp.1-9
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• 2006

The purpose of this study is to make a design guideline in designing constructed wetland which can treat water quality both of point and nonpoint source water pollution. It focuses on structural aspects of two case studies of constructed wetland applying SSB(Sustainable Structured wetland Biotope) system in Korea. The constructed wetland of Lake Ju-am which was constructed in 2002 by Environmental Management Corporation, was designed by applying SSB system. It shows higher removal efficiency than expected - 56% of BOD removal efficiency, 60% of T-N removal, and 76% of T-P removal efficiency. In two cases, total wetland areal extents were calculated referred to treatment efficiency. The system is consist of micro-cell structures : inflow channel, forebay, multiple wetland cells and micro-pool. When designing constructed wetland appropriate in local area, the total organic system of vertical and horizontal structure : geology, hydrology, land use, and ecological surroundings of the sites should be considered totally.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.5
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• pp.1-11
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• 2004

In order to recognize thermal efficiency and power improvement in case that diesel cycle is turned into diesel-atkinson cycle, the fuel-air diesel-atkinson cycle considered gas exchange process is analyzed non-dimensionally and thermodynamically. As a result, in case of diesel-atkinson cycle, as expansion ratio is increased, thermal efficiency and mean effective pressure is increased and it has maximum value at Rec=1. When diesel cycle is turned into diesel-atkinson cycle by late intake valve closing timing, thermal efficiency and power is decreased because of the decline of effective compression ratio and intake airflow, but it could be compensated by increase of compression ratio or super-charged. In case compression ratio is compensated, Rec appears 1 around 100$^{\circ}$ ABDC, and it is expected that thermal efficiency is enhanced by 14.3% compared with conventional diesel cycle. In case compression ratio and intake airflow are compensated simultaneously, super-charged pressure is demanded 2.06bar at Rec=1 and it is more efficient when only compression ratio is compensated in the view point of thermal efficiency.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.138-143
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• 2011

Until now, measures for energy saving in buildings have been tried. Because particularly the role of buildings area is very important for implementing national greenhouse gas reduction targets and Green growth. But, lack of business linkages between each sector or the interest and participation of private sector are not enough. In addition, relevant personnel to do had not been systematized. It is expected that certification services will be increased according to the activation of Building Energy Efficiency Rating System and expansion of the target buildings so Government must be prepared to expand of certification system by training Professional staff. In this study, the basic data for the introduction of obligation of Building Energy Efficiency Rating System is suggested through analysis of the operating and laws system of Building Energy Efficiency Rating System along with efforts of Government for diffusion low energy buildings.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.11
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• pp.747-757
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• 2020

This study investigates the impact of bank regulation and supervision on the efficiency of banking sectors on 108 Islamic banks from 26 countries offering Islamic banking and finance products and services. The technical efficiencies of individual Islamic banks have been analyzed using the data envelopment analysis method (DEA). The ordinary least square estimation method is employed to examine the impact of country supervision and regulation on the technical efficiency of Islamic banks. The empirical findings suggest that supervisory power, activity restrictions and private monitoring positively influence the efficiency of Islamic banks. The study revealed that Islamic banks that are operating in Middle East and North Africa (MENA) and middle-income countries are more technically efficient given the less stringent rules on capital requirement and we found that there is statistically significant evidence that higher capital requirements are negatively associated with the efficiency of Islamic banks. The empirical findings of this study are expected to help policy-makers and government officials to better understand how their decisions affect the performance.

• The KSFM Journal of Fluid Machinery
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• v.12 no.4
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• pp.30-36
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• 2009

Recently, there has been growing interest in the oxyfuel combustion cycle since it enables high-purity $CO_2 capture with high$ efficiency. However, the oxyfuel combustion cycle has some important issues regarding to its performance such as the requirement of water recirculation to decrease a turbine inlet temperature and proper combustion to enhance cycle efficiency. Also, Some of water vapour remain not condensed at condenser outlet because cycle working fluid contains non-condensable gas, i.e., $CO_2$. The purpose of the present study is to analyze performance characteristics of the oxyfuel combustion cycle with different turbine inlet temperatures, combustion pressures and condenser pressure. It is expected that increasing the turbine inlet temperature improves cycle efficiency, on the other hand, the combustion pressure has specific value to display highest cycle efficiency. And increasing condensing pressure improves water vapour condensing rate.