• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.6
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• pp.708-719
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• 1995

This study is to estimate abundance of the Chesapeake Bay blue crab stock. Using 823 dredge tows which were conducted during the 1991 winter survey, blue crab abundance was estimated on the basis of newly developed methods which account for unequal dredge tow distances, size- and sex-specific heterogeneous overwintering spatial distributions, wintertime exploitation, the time period of quasi-hibernation, and dredge capture efficiency. The estimate of total abundance before correction by gear efficiency was 131.8 million crabs $(95\%\;C.I.\;=\;118.2\;million\;crabs\;to\;145.4\;million\;crabs),$ Dredge capture efficiency was estimated to be 0.474. Thus, the estimate of total abundance was calculated as 278.1 million crabs after correction by the efficiency factor.

• The Journal of Fisheries Business Administration
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• v.34 no.2
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• pp.109-129
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• 2003

The purpose of this study is to evaluate the managerial efficiency of fisheries cooperatives in Korea by using data envelopment Analysis(DEA). The DEA method is a relative evaluation method on the basis of linear programming. Also, it is known as a useful method for the evaluation of not-for-profit organizations which cannnot be measured by mere monetray units for their performances. The 50 units have been taken for the purpose of analysis. All of the units are homogeneous groups, and the produce multiple services with multiple inputs. Input variables are a number of employee, fixed assets, and business managerial costs. Output variables include a number of deposits, a number of loans, a total deposits, a total loans, and operational income for one year. The empirical results of this study are as follows. First, the average technical efficiency showed 82.35% which revealed about 17.65% of non-efficiency in 2001. Second, in 15 DMUs, the overall inefficiency is mainly attributed to their efficient operations or management. To be opposed, in 18 DMUs, the overall inefficiency is mainly attributed to their scale efficiency. Third, efficiency ranking results by DEA do not agree with the ratio analysis by fisheries cooperatives. Fourth, average efficiency level by year was improving gradually by 0.7408 in 1999, 0.8023 in 2000, and 0.8235 in 2001 at significant 10% level.

• Journal of Navigation and Port Research
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• v.46 no.2
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• pp.110-120
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• 2022

Spain is Europe's second-largest country with total throughput reaching 16.7 million twenty-foot equivalent units (TEU) by 2020. The purpose of this study was to measure and compare the efficiency of 17 container terminals. As a study method, the DEA-CCR model, undesirable variable, and Malmquist Index (MI) were used for data envelopment analysis (DEA). The study results are as follow: (1) DEA-CCR is used to evaluate basic efficiency. The most efficient terminals are decision-making units DMU 1 (APM Terminals (Algeciras Port)), DMU 2 (Total Terminal International Algeciras (Algeciras Port)) and DMU 5 (Barcelona Europe South Terminal (Barcelona Port)). (2) Undesirable DEA was conducted to suggest inefficiency from the undesirable output. Overall, the efficiency scores were reduced. However, DMU 1, DMU 2, and DMU 5 maintained efficiency scores regardless of the finish factor. (3) Malmquist Index was used to observe technology and efficiency changes dynamically. The changes in TCI affected Spanish container terminals more than the Technical Efficiency Change Index (TECI) in 2018-2019. However, in 2019-2020, the TECI was 2.706, higher than the TCI value, indicating that the change in TECI had more influence on the increase in productivity. This study offers a broader understanding of Spanish container terminals.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.11
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• pp.1033-1039
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• 2020

Vietnam is conducting an export-led growth model and labour-intensive industries contributing majorly to the total export value. In the context of Industry 4.0, the labour-based industries are significantly affected; hence, enhancing productivity is the key measure to maintain these industries. The garment industry contributes significantly to the total export value of Vietnam. Based on meta-frontier framework, the approach of data envelopment analysis is used to measure technical efficiency of Vietnamese garment firms and the global Malmquist TFP index is utilised to identify productivity change and its components including efficiency, technology and technical gaps between different groups of firms. The data of Vietnamese garment firms from 2013 to 2018 collected from the Vietnam General Statistic Office is used in this study. The results show that: (i) The total factor productivity of Vietnamese garment firms growth, technical progress is the main contributor; (ii) The private garment sector is the leading group; (iii) There is a large technological gap among Vietnamese garment sectors. The private and FDI garment firms have experienced a growth in all components of total factor productivity change. Meanwhile, technological progress change is the main reason to constrain the productivity growth of state-owned garment firms.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.9
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• pp.1292-1301
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• 2002

An experimental study of turbine performance is conducted with various incidence angles on a rotating turbine rotor. 5 different incidence angles are applied from -17$^{\circ}$to 13$^{\circ}$with 7.5$^{\circ}$gaps. In order to precisely set up the incidence angles at the rotor inlet, 5 turbine discs are manufactured with the different fir tree section. Total-to-total efficiencies are obtained on the several off-design points with considering the exit total pressure, which is meas fred at 12 locations between the hub and casing using a pressure rake. The degree of reaction is 0.373 at the mean radius, and Reynolds number based on the rotor chord is 0.86$\times$10$^{5}$ at the turbine inlet on the design point experiment. The experiment on a single-stage turbine is conducted at the low-pressure and low-speed state, but it is sufficient to consider the blade loading effect due to the rotating apparatus even though the total pressure loss at the exit is increased proportionally to the turbine output power. The experimental results recommend 6$^{\circ}$as an optimum incidence angle on the turbine blade design. The total-to-total efficiency is steeply decreased when the incidence angle is over $\pm$9$^{\circ}$ from the optimum incidence angle. In the range of less than -10$^{\circ}$incidence angle, 7.5$^{\circ}$ reduction of incidence angle generates 15% decrease of total-to-total efficiency. This result is obtained on the same rotor blade by changing only the rotational speed to minimize the effect of profile and secondary flow loss in the passage. Experimental results show that the change rate of total-to-total efficiency according to the incidence angle change is unchanged although the turbine operates at the off-design condition.

• Korea Journal of Hospital Management
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• v.21 no.1
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• pp.43-50
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• 2016

The public medical centers are required to make efficient and profitable operation. The efficiency is usually measured by DEA(data envelopment analysis), and profitability is measured by medical income rate. But DEA is measured by relative, not absolute value. So, profitability rate is used alternatively for DEA. This study want to analyze the interchangeability between DEA ranking and medical income rate ranking among public medical centers. The return on total assets is same ranking with DEA on bed number, employee number and total asset, but 60-70% relationship with DEA on bed number and employee number, as input resources. The operating margin is similar ranking with DEA on bed number and employee number, but 50-60% relationship with DEA on bed number, employee number and total asset, as input resources.

• Journal of Power System Engineering
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• v.13 no.4
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• pp.31-37
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• 2009

The purpose of this numerical study was to investigate performance characteristics for cooling tower axial fans with sweep. Performance data for the fans with various sweep angles were obtained in terms of the setting angle at a constant flow rate. Viscous flow calculations were carried out to obtain Performance data of the total pressure rise and hydraulic efficiency. A solution of the Ffowcs Williams-Hawkings equations was used to calculate the sound pressure level at three times fan diameter away from the fan. The calculated performance data well represented performance characteristics of the cooling tower axial fan. The total pressure rise and hydraulic efficiency at the same setting angle decreased with sweep angle. Sound pressure level slightly decreased for the fan with a sweep angle of 10 degree. No significant effect of the sweep geometry was found on the sound pressure level.

• Journal of the Korean Applied Science and Technology
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• v.23 no.2
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• pp.130-136
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• 2006

Theoretical total nitrogen removal efficiency and reactor volume ratio in oxic-anoxic-oxic system can be found by influent water quality in this study. The influent water quality items for calculation were ammonia, nitrite, nitrate, alkalinity, and COD which can affect nitrification and denitrification reaction. Total nitrogen removal efficiency depends on influent allocation ratio. The total nitrogen removal follows the equation of 1/(1+b). Optimal reactor volume ratio for maximum TN removal efficiency was expressed by those influent water quality and nitrification/denitrification rate constants. It was possible to expect optimal reactor volume ratio by the calculation with the standard deviation of ${\pm}14.2$.

• Applied Science and Convergence Technology
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• v.26 no.1
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• pp.1-5
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• 2017

The spurt vacuum pump is widely used to transfer sludge and slurry, and to control flow rate in a variety of processing fields, such as the oil, chemical, and fiber industries. The efficiency of the pump depends on the design parameters of the impeller, such as the number of blades, and the blade angle. In this study, the effect of the configuration of the impeller discharge angle of a spurt vacuum pump, which influences total head, shaft power, and efficiency, was numerically investigated using the commercial code, ANSYS CFX ver. 16.1. In addition, the performance of the pump was evaluated on the basis of the correlations between the total head, pump efficiency, and pressure distribution.

• Journal of the Korean Data and Information Science Society
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• v.19 no.4
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• pp.1449-1463
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• 2008

This paper considers three different models with two functional forms, Cobb-Douglas and Translog, for the stochastic frontier production function of food manufacturing industry of Bangladesh over the period 1981-1982 to 1999-2000. The models are proposed by Battese and Coelli (1992, 1995) and Huang and Liu (1994). The technical efficiency, total factor productivity, technological change and technical efficiency change have been estimated in the frontier models. The results indicate that 41.47%, 59.30% and 70.98% of the potential output are being realized in this sector. The mean increments in total factor productivity are approximately 2%, 9% and 4% respectively.