• Journal of Integrative Natural Science
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• v.16 no.4
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• pp.139-145
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• 2023

Due to changes in the distribution system and increased demand for renewable energy, interest in technology to increase the limit capacity of distributed energy grid connection using grid flexible resources is also increasing. Recently, the distribution system system is changing due to the increase in distributed power from renewable energy, and as a result, problems with the limited capacity of the distribution system, such as waiting for renewable energy to connect and increased overload, are occurring. According to the power generation facility status report provided by the Korea Power Exchange, of the total power generation capacity of 134,020 MW as of 2021, power generation capacity through new and renewable energy facilities is 24,855 MW, accounting for approximately 19%, and among them, power generation through solar power accounts for a total portion of the total. It was analyzed that the proportion of solar power generation facilities was high, accounting for 75%. In the future, the proportion of new and renewable energy power generation facilities is expected to increase, and accordingly, an efficient operation plan for the distribution system is needed. Advanced country-type NWAs that can integrate the operation and management of load characteristics for each line of the distribution system, power distribution, regional characteristics, and economic feasibility of distributed power in order to improve distribution network use efficiency without expanding distribution facilities due to the expansion of renewable energy. An integrated operating system is needed. In this study, in order to improve the efficiency of distribution network use without expanding distribution facilities due to the expansion of renewable energy, we developed a method that can integrate the operation and management of load characteristics for each line of the distribution system, power distribution, regional characteristics, and economic feasibility of distributed power. We want to develop an integrated operation system for NWAs similar to that of advanced countries.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.150-154
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• 2009

Flow distribution characteristics with varying inlet flow-rate in mega collector risers have been investigated, using commercial code FLUENT. The heat transfer in mega collector was not considered in this numerical study. Through the simulation, the following results were found. First, flow distribution characteristics in mega collector risers show the similar tendency in all cases. Secondly, with increased inlet flow-rate, flow distribution uniformity was getting worse.

• Journal of the Korean housing association
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• v.1 no.1
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• pp.91-102
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• 1990

The aim of this study is to discover thermal characteristics of Ondol heating systems. The housing subjected was categorized into detached single family houses and apartments, reinforced concrete and brick structures, intermittent and continous heating system, and the space subjected was bedroom. In order to understand the thermal characteristics of each floor heating systems, the vertical distribution of indoor temperature and the distribution of surface temperature on the floor were measured. The vertical distribution of indoor temperature except the measurement point 1 largely showed average temperature distribution, and the temperature of the measurement point 1 in the housing surveyed showed the highest temperature in the house "sample A" because of the radiation heating from the floor of the Ondol room. As the result of the measurement, the thermal characteristics of each heating system were more stable distribution in apartments of R.C structure.structure.

• Journal of Distribution Science
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• v.20 no.11
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• pp.71-78
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• 2022

Purpose: The study aims to investigate the impact of factors affecting the work motive distribution of public universities lecturers in Hanoi. Research design, data and methodology: The questionnaire survey method is applied in this research to analyze the relationship between the variables and verify the hypothesis based on the collected 306 valid questionnaires. The partial least square method structural equation model (PLS-SEM) is used to carry out structural equation modeling to study the relationship between latent variables with reliable tools (SmartPLS 3.0 software). Results: The research results show that the intrisic motivation of the lecturers, the extrisic motivation of the lecturers and the job characteristics of the lecturers all have a positive impact on the motivation of public universities lecturers in Hanoi. In which, intrinsic motivation has the greatest influence on the work motive distribution of lecturers. In addition, the research results also prove that job characteristics affect the work motive distribution of lecturers. This is a new factor in the factors affecting the work motive distribution of public universities lecturers. Conclusion: Based on the research results, the authors propose some recommendations to increase the work motive distribution of public universities lecturers in Hanoi through improving the factors affecting their work motive distribution.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.3 s.258
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• pp.283-291
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• 2007

The static pressure distribution, atomization characteristics and velocity distribution of tapered nozzle swirl spray is analyzed and then compared with original swirl spray. The static pressure distribution inside the swirl spray is measured using a piezoresistive pressure transducer. Phase Doppler anemometry (PDA) is applied to measure and analyze the droplet size and velocity distribution of tapered nozzle and original swirl spray. The static pressure inside the spray shows the lower value compared to the atmospheric pressure and this pressure drop is getting attenuated as the taper angle is increased. The droplet size of tapered nozzle spray shows similar value compared to the original swirl spray at the horizontal mainstream while it shows increased value at vertical mainstream. The deteriorated atomization characteristics of tapered nozzle spray is improved by applying high fuel temperature injection without causing the spray collapse. The velocity results show that the larger portion of fuel is positioned with higher injection velocity, and the smaller portion of fuel is positioned with lower injection velocity with causing spatially non-uniform mixture distribution.

• Journal of Distribution Science
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• v.21 no.2
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• pp.119-129
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• 2023

Purpose: This study intended to examine the effects of the characteristics of platforms for purchasing airline tickets on perceived ease of use, usefulness, and e-loyalty, applying the technology acceptance model. Research design, data and methodology: A research model was established based on previous studies, and data were collected from consumers with experience in the airline ticket purchasing platform. 175 valid samples were used and analyzed using SEM. Results: Characteristics of the ticket purchase platform were classified into sub-factors of accessibility, functionality and information reliability through theoretical consideration. The established hypotheses for the research were partially accepted. Conclusions: First, functionality and information reliability were found to have significant positive effects on perceived ease of use, while accessibility did not have such effect. Second, accessibility did not affect the perceived usefulness, and both functionality and information reliability had a significant positive effect on perceived usefulness. Third, it was found that the perceived ease of use had a positive effect on perceived usefulness. Finally, it was found that perceived ease of use did not affect e-loyalty of the ticket purchasing platform, only perceived usefulness affected e-loyalty. This study had important academic and practical implications in the context of air ticket distribution.

• Journal of Distribution Science
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• v.18 no.8
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• pp.5-14
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• 2020

This study aims to examine the impact of characteristics of SNS content provided by airlines on customer satisfaction and to explore the effect of the personal characteristics of the customers which have a modulating effect on the relationship between content characteristics of SNS and customer satisfaction. The data were collected over a period of April 21. 2019. to July 21. 2019. for three months from the people who have experience using SNS provided by airlines. 225 samples were selected and used as final samples from a collection rate of 93.4 percent. Findings suggest that the characteristics of airline's SNS content which include a promotion, information, and communication showed a positive impact on customer satisfaction. The analysis of a modulating effect of individual characteristics on the relationship between the airline's SNS content characteristics showed that diversity pursuit propensity, innovation propensity, and information-seeking propensity control the relationship between characteristics of airline's SNS content which are publicity, information and customer satisfaction. And it was found that all three personal characteristics do not control the relationship between communication and customer satisfaction. Thus, airlines should use SNS more effectively to generate customer satisfaction and present marketing measures to help generate profits through consumer purchasing behavior. It is expected that the findings of this study will help airlines to utilize marketing implications for effective and practical marketing methods.

• Journal of Agricultural Extension & Community Development
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• v.14 no.1
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• pp.197-230
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• 2007

The objectives of this study were to identify the cause of consumers for purchasing foods from various distribution channels, and to compare with characteristics of consumers by each distribution channel. The distribution channels as the basis of comparison were four types namely, the consumer cooperatives / environment－friendly specialized stores, large retail discount stores, direct marketing and parents / relatives. The researcher developed a questionnaires, and a total of 190 questionnaires were collected and 186 of them were analyzed. The data were analyzed utilizing the SPSS－WIN 12.0K program and major statistical technique were mean, percentage, t－test, Chi－square test, ANOVA. There were differences in the quality perception, demographical characteristics, relationship with rural communities and personal experiences of the consumers according to the distribution channels.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.11
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• pp.559-567
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• 2002

This paper presents the general recommendations for the overload criterions of mineral-oil-immersed distribution transformers rated 100kVA and less. For this purpose, we analyze the characteristics of top-oil temperature rising for mineral-oil-immersed power distribution transformer rated 100kVA and less, manufactured in Korea, In order to analyze the characteristics of top-oil temperature rising due to the distribution transformer loading, we performed experiments at KERI (Korea Electrical Research Institute) from December 2000 to May 2001. The restraint of ambient temperatures for the experiment results is solved using the results of foreign standards. Finally, we present the overload criterions of distribution transformer for summer and winter season, respectively.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.12
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• pp.704-713
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• 2002

This paper describes operational characteristics of wind turbine induction generators interconnected with distribution networks using PSCAD/EMTDC. Due to the simple and durable structure, induction generators are the most common type used in wind Power generation. Generally, induction generators are classified into two groups according to the shape of rotor, one is squirrel-cage type and the other is wound-rotor type. In this study, we simulate the start-up and the output variation of generators interconnected with distribution networks and compare the operational characteristics of squirrel -cage type and wound-rotor type induction generators located in the unfaulted distribution lines about the disturbance occurred on the associated distribution feeders emanated from the substation to which wind turbine generator is connected. In order to obtain the realistic results, we use the radial distribution network of IEEE 13-bus model.