• Transactions of the Korean hydrogen and new energy society
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• v.13 no.4
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• pp.304-312
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• 2002

In this study, the performance of the $5Nm^3/hr$ compact type steam reformer which was developed for application of fuel cell or hydrogen station was evaluated in terms of gas process efficiency. For these purposes, reforming efficiency and total efficiency with system load change were analyzed. The reforming efficiency was calculated from the total molar flow of hydrogen output over total fuel flow input to the reformer and the burner on the higher heating value(HHV). In the case of the total efficiency, recovered heat at the heat recovery exchanger was considered. From the results, it was known that system performance was stable, because methane conversion showed the a slight decline which is about 2% though increasing system load to full. Reforming efficiency was increased from 20% to 58%, respectively as increasing system load from 10% to 90%. It was found that total efficiency was higher then reforming efficiency because of terms of heat recovered. As a results, it was known that total efficiency was increased form 75% to 83% at the 10% and 90% system load, respectively. From these results, it is concluded that compact steam reformer which is composed of stacking plate-type reactors is suitable to on-site hydrogen generator or to fuel cell application because of quick start within 1 hr and good performance.

• Journal of Radiation Protection and Research
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• v.38 no.4
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• pp.172-178
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• 2013

In this study, neutron detection efficiency of the UNDA system, which has been developed for study on nuclear material accountancy in a future pyro-process facility, was evaluated by using the MCNPX code. The detection efficiency was evaluated as a function of (1) positions of $^{252}Cf$ neutron source in the axial and radial directions, and (2) thicknesses and locations of the container filled with the depleted uranium materials for two different designs of the UNDA. In the case of $^{252}Cf$ source positions, detection efficiency was distributed from 6.83% to 13.35%. As $^{252}Cf$ source was positioned at upper part in the axial direction, detection efficiency was decreased after a slight increase. On the other hands, as $^{252}Cf$ source was positioned at outer part in the radial direction, detection efficiency was increased. In the case of container thickness, there was a slight decline when the thickness was increased. As the container was located at upper part, detection efficiency was decreased and as the container was located at outer part, detection efficiency was increased. Detection efficiency was varied from 10.31% to 13.61%. These values were higher than that of $^{252}Cf$ source case. The UNDA with polyethylene cover has about 2% higher detection efficiency than the UNDA without the cover.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.7
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• pp.439-451
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• 2020

This study focused on researching the factors affecting retail banking efficiency of Vietcombank branches in the Mekong-Delta region. By collecting data from financial statements from 15 branches of VCB in the Mekong-Delta Region between 2015 and 2018, the paper applies DEA estimation to measure the effectiveness of retail banking activities and uses the Tobit regression model to identify factors affecting retail banking efficiency. The results demonstrate that the retail banking efficiency of branches averaged 52.5% during the period. The rating result shows the branches in An Giang, Can Tho, Dong Thap, Kien Giang, Long An, Phu Quoc and Tra Noc rank at the top technical efficiency. In group of medium efficiency, there are branches in Soc Trang, Tien Giang and Vinh Long. In the category of the poor efficiency are the branches in Bac Lieu, Ben Tre, Ca Mau, Chau Doc and Tra Vinh. The results also show that bank scale-related factors, capital adequacy, credit quality, time specific and region impact significantly the retail banking efficiency. The research not, only contributes to enriching the empirical research method but also is significant for the management activities in business developing strategies, improving the operational efficiency of Vietcombank in the region.

• Asia-Pacific Journal of Business
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• v.12 no.2
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• pp.1-24
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• 2021

Purpose - We aim to verify whether CSM activities increase investment efficiency, and to verify whether the influence of CSM activities on investment efficiency is discriminatory depending on whether or not they belong to chaebol. Design/methodology/approach - Using 4,701 Korean firm-year observations over the 2011-2017 period, we used multiple regression analysis. CSM is measured by the evaluation score of the Korea Corporate Governance Service (KCGS). Findings - Our study confirms that CSM is a significantly positive relationship with investment efficiency. This shows that, as a result of CSM, the increased earnings quality acts as an incentive to increase investment efficiency. Next, in analysis of a dataset into two groups (a chaebol, non-chaebol), the results show that the relationship between CSM and investment efficiency differs among detailed indicator activities depending on whether or not they belong to chaebol. Research implications or Originality - It is significant that this study focused on and analyzed CSM as a determinant of investment efficiency, and examined the effects of whether or not it belongs to chaebol in the relationship between CSM and investment efficiency. Our results, which suggested that CSM can increase investment efficiency, are expected to provide important implications not only for managers but also for investors and supervisors.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.628-649
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• 2017

Security and resource-saving are both demands of the fifth generation (5G) wireless networks. In this paper, we study the secrecy spectrum efficiency (SSE) and secrecy energy efficiency (SEE) of a K-tier massive multiple-input multiple-output (MIMO) enabled heterogeneous cellular network (HetNet), in which artificial noise (AN) are employed for secrecy enhancement. Assuming (i) independent Poisson point process model for the locations of base stations (BSs) of each tier as well as that of eavesdroppers, (ii) zero-forcing precoding at the macrocell BSs (MBSs), and (iii) maximum average received power-based cell selection, the tractable lower bound expressions for SSE and SEE of massive MIMO enabled HetNets are derived. Then, the influences on secrecy oriented spectrum and energy efficiency performance caused by the power allocation for AN, transmit antenna number, number of users served by each MBS, and eavesdropper density are analyzed respectively. Moreover, the analysis accuracy is verified by Monte Carlo simulations.

• Journal of the Korean Solar Energy Society
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• v.34 no.6
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• pp.1-10
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• 2014

The efficiency of the maximum power point tracking(MPPT) of inverter which is used in grid-connected photovoltaic systems is changed according to dynamic environment conditions. Hence, this paper evaluates the performance of the proposed method and other MPPT algorithm on the basis of European Efficiency Test(EN50530). The modeling of MPPT algorithm is made by the Matlab & Simulink. In the result of simulation, the more control period is shorter, the more MPPT efficiency is higher. Also, the Proposed MPPT algorithm has higher performance than other MPPT algorithm with no regard to control period.

• The Journal of Industrial Distribution & Business
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• v.14 no.3
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• pp.19-26
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• 2023

Purpose: There is little emphasis on alternative forms of communication in psychotherapy, thus leaving a gap in research on the impact and effects of alternatives such as using artistic expressions. The current research, therefore, seeks to address the gap by investigating the effect of psychological counseling using Art Therapy on improving workers' job efficiency. Research design, data and methodology: The present author collected topic related to prior studies in terms of psychological counseling, art therapy, and employee job efficiency. And then, the author conducted clear procedure of the screening to eliminate inappropriate previous works including conference papers and dissertations so that this research could obtain only journal articles and books which have been proven by high degree of reliability and validity. Results: This research has concluded that psychological counselling using art therapy is pertinent to improving the worker's job efficiency in various ways, addressing properly mental health issues ranging from small to complicated or acute issues, thus promoting the well-being of employees to work at their optimum or best possible conditions. Conclusions: Psychological counseling using art therapy improves self-confidence, esteem, and awareness. Further, it enhances their social skills, expression capability, and general work ability. Elsewhere it improves coping with pain and reduces stress and depression.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.61-64
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• 2008

We investigated experimentally the influence of the generation efficiency for excited Xe atoms on ultra-fine horizontal cell pitch AC PDPs. In the case of a 0.1 mm cell pitch, the sustain voltage increased; however, the generation efficiency was equal to or higher than for the conventional 0.22 mm cell pitch.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.1-3
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• 2005

This paper is to evaluate practical advantage in using maximizing efficiency control strategy in induction motor drives for electric vehicles. A maximizing efficiency control strategy consist of a flux estimation with direct field oriented controller is proposed and compared with the general constant flux control strategy. The comparison is carried out by simulation.

• Nuclear Engineering and Technology
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• v.45 no.5
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• pp.675-682
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• 2013

The sequential separation process, composed of an oxygen sparging process for separating lanthanides and a zone freezing process for separating Group I and II fission products, was evaluated and tested with a surrogate eutectic waste salt generated from pyroprocessing of used metal nuclear fuel. During the oxygen sparging process, the used lanthanide chlorides (Y, Ce, Pr and Nd) were converted into their sat-insoluble precipitates, over 99.5% at $800^{\circ}C$; however, Group I (Cs) and II (Sr) chlorides were not converted but remained within the eutectic salt bed. In the next process, zone freezing, both precipitation of lanthanide precipitates and concentration of Group I/II elements were preformed. The separation efficiency of Cs and Sr increased with a decrease in the crucible moving speed, and there was little effect of crucible moving speed on the separation efficiency of Cs and Sr in the range of a 3.7 - 4.8 mm/hr. When assuming a 60% eutectic salt reuse rate, over 90% separation efficiency of Cs and Sr is possible, but when increasing the eutectic salt reuse rate to 80%, a separation efficiency of about 82 - 86 % for Cs and Sr was estimated.