• Journal of Power Electronics
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• v.16 no.4
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• pp.1598-1611
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• 2016

In some special occasions with strict size requirements, such as mine hoists, improving the design accuracy of the forced-air cooling systems of NPC three-level inverters is a key technology for improving the power density and decreasing the volume. First, a fast power-loss calculation method was brought. Its calculation principle introduced in detail, and the computation formulas were deduced. Secondly, the average and dynamic power losses of a 1MW mine hoist acting as the research target were analyzed, and a forced-air cooling system model based on a series of theoretical analyses was designed with the average power loss as a heat source. The simulation analyses proves the accuracy and effectiveness of this cooling system during the unit lifting period. Finally, according to an analysis of the periodic working condition, the maximum power-loss range of a NPC three-level inverter under multi cycle operation was obtained and its dynamic power loss was taken into the optimized cooling system model as a heat source to solve the power device damage caused by instantaneous heat accumulation. The effectiveness and feasibility of the optimization design based on the dynamic power loss calculation of the maximum power-loss range was proved by simulation and experimental results.

• Journal of Computational Design and Engineering
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• v.2 no.1
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• pp.16-25
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• 2015

Since construction projects are large and complex, it is especially important to provide concurrent construction process to BIM models with construction automation. In particular, the schematic Quantity Take-Off (QTO) estimation on the BIM models is a strategy, which can be used to assist decision making in just minutes, because 70-80% of construction costs are determined by designers' decisions in the early design stage. This paper suggests a QTO process and a QTO prototype system within the building frame of Open BIM to improve the low reliability of estimation in the early design stage. The research consists of the following four steps: (1) analyzing Level of Detail (LOD) at the early design stage to apply to the QTO process and system, (2) BIM modeling for Open BIM based QTO, (3) checking the quality of the BIM model based on the checklist for applying to QTO and improving constructability, and (4) developing and verifying a QTO prototype system. The proposed QTO system is useful for improving the reliability of schematic estimation through decreasing risk factors and shortening time required.

• Journal of the Korean Solar Energy Society
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• v.33 no.2
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• pp.42-49
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• 2013

Recently, the attention to renewable energy has increased globally because of the environmental issue and the global energy crisis. Accordingly, south korea is focused on increasing the renewable energy usage. And the government enforced a law to the public buildings to install the renewable energy facilities. In this study, the building to evaluate renewable energy consumption and supply ratio was selected. This building has 9.79% of renewable energy supply ratio by PV system. In this study, the method for improving renewable energy supply ratio was analyzed using additional PV system. And The 5 methods to increasing electricity were evaluated. The method of increase 4.24 times PV arrays area is most efficient way to increase the renewable supply ratio. The case 1, show that the increasing renewable energy supply ratio of 39.2% compared to exsiting PV system. The result of the above, consider the additional supply of renewable energy.

• Journal of Digital Convergence
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• v.11 no.9
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• pp.357-363
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• 2013

This study aims to establish and apply a mobile office app for approving the achievements of tasks assigned to each person to investigate resulting satisfaction. This is done first by implementing the app for approval in a company with smart phones to enable tasks to be carried out any time and anywhere while the mobile office environment changes the method of carrying out tasks. More efficient work environment is expected if the system implemented in this study is improved in cooperation with customer's requirements. Matters for improving work efficiency added to the approval management system through this app will contribute to efficiently and continuously improving the mobile office environment to enhance productivity and efficiency of a company.

• Journal of the Korean Society of Earth Science Education
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• v.9 no.1
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• pp.1-14
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• 2016

The purpose of this study is to develop SPA system using diagnostic and formative assessment in earth science classes in order to discuss its effect on learning achievement and self-directed learning attitude. For this purpose, we developed total management system, app for teachers, and app for students. This research was practiced to 76 students in 5th grade. The results are as follows. Firstly, the group taking a class used by app for diagnostic and formative assessment had an effect of improving learning achievement. However, as for learning achievement long term endurance test, the group taking a class using app for diagnostic and formative assessment had no effect. Secondly, the group taking a class using apps for diagnostic and formative assessment had an effect of improving learners' self-directed learning attitude. As for self-directed long-term endurance test, the group taking a class using app for diagnostic and formative assessment had an effect. In conclusion, I hope that this SPA system might apply to the science classes as it is a system that will satisfy the needs of both teachers and students, giving much needed feedback to students.

• The Journal of the Convergence on Culture Technology
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• v.7 no.1
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• pp.615-619
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• 2021

This study focuses on memory systems that are optimized to increase performance and energy efficiency in many embedded systems such as IoT, cloud computing, and edge computing, and proposes a performance improvement technique. The proposed technique improves memory system performance based on machine learning algorithms that are widely used in many applications. The machine learning technique can be used for various applications through supervised learning, and can be applied to a data classification task used in improving memory system performance. Data classification based on highly accurate machine learning techniques enables data to be appropriately arranged according to data usage patterns, thereby improving overall system performance.

• Journal of Korea Society of Digital Industry and Information Management
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• v.16 no.4
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• pp.111-121
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• 2020

This study analyzed the effects on system quality, learning commitment, and satisfaction in a mobile environment. A survey was conducted on 192 students enrolled in K University, and the research results are as follows. first, it was found that usefulness had an effect on learning commitment, but connectivity and reliability did not affect learning commitment. second, it was found that the usefulness and connectivity of the system quality had a significant effect on the satisfaction of use. third, the intermediary effect of learning immersion was verified as the connectivity, reliability, and usefulness of the system quality influence the satisfaction of use. connectivity and reliability had no mediating effect of learning commitment, and usefulness was found to play a partial mediating role in affecting user satisfaction. This study is meaningful in that it can provide a plan for improving the quality management of mobile learning and improving the learning effect by analyzing the effects on mobile learning from multiple perspectives.

• Korean Journal of Veterinary Service
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• v.43 no.4
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• pp.267-271
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• 2020

The emergence of highly contagious viral diseases of livestock and poultry such as foot-and-mouth disease (FMD), African swine fever (ASF) and highly pathogenic influenza (HPAI) have necessitated the formulation of policies and regulatory frameworks for preventing ingress of exotic diseases and controlling dissemination of endemic diseases within the country. The disease control ratings to manage contagious livestock disease in farms have not being widely used because the evaluation parameters were not being considered inappropriate. The purpose of this study was to reinforce the validity of the parameters for evaluation factors and the objectivity of the scoring criteria in the application of the current disease management rating system. The diseases subject to intensive management were improved by reflecting farm situation. For the evaluation based on the disease grading system of farms, the diseases subject to intensive management were realized, the list of diseases for evaluating the vaccination rate was revised, and the quarantine and sanitation management standards were revised. The effectiveness of the improved livestock disease management system was confirmed through the application of actual pig farms. Therefore, this system will be used as a means to evaluation the biosecurity at the farm units. Through this, it will contribute to establish effective biosecurity measures for each farm by improving and supplementing the present disease grading system.

• International Journal of Computer Science & Network Security
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• v.23 no.12
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• pp.123-128
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• 2023

The main purpose of the study is to analyze the features of the influence of Agile management on the competence of the personnel of the socio-economic system in the digital economy. The research methodology implies the use of modern methods of analysis. Improving the business processes of an organization is associated with improving activities, the formation of effective management systems and processes, especially the organization's policy in the field of quality, rational use of resources, increasing the responsibility of management, social responsibility of the organization, etc. The modern knowledge economy places high demands on the effectiveness of behavioral models of employees of the organization. The role of the human factor in the production system is becoming more and more obvious. Therefore, it is important to study the competence of the personnel of any socio-economic system. Based on the results of the study, the key features of the influence of Agile management on the competence of the personnel of the socio-economic system in the digital economy were identified.

• International Journal of Computer Science & Network Security
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• v.23 no.12
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• pp.161-166
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• 2023

The main purpose of the study is to analyze the features of the influence of Agile management on the competence of the personnel of the socio-economic system in the digital economy. The research methodology implies the use of modern methods of analysis. Improving the business processes of an organization is associated with improving activities, the formation of effective management systems and processes, especially the organization's policy in the field of quality, rational use of resources, increasing the responsibility of management, social responsibility of the organization, etc. The modern knowledge economy places high demands on the effectiveness of behavioral models of employees of the organization. The role of the human factor in the production system is becoming more and more obvious. Therefore, it is important to study the competence of the personnel of any socio-economic system. Based on the results of the study, the key features of the influence of Agile management on the competence of the personnel of the socio-economic system in the digital economy were identified.