• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.9
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• pp.1240-1248
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• 2013

This paper describes a switching-level operation analysis of BTB(Back-To-Back) converter for HVDC(high voltage DC) application based on MMC(modular multi-level converter). A switching-level operation analysis for BTB converter is very important to understand the converter operation in detail and check the voltage and current transients in each components. However, the development of switching-level simulation model for the actual size BTB Converter is very difficult because the MMC normally has more than 150 sub-modules for each arm. So, a switching level simulation model for the 11-level MMC-based BTB converter was developed with PSCAD/EMTDC software, which has 12 sub-modules for the positive arm and another 12 sub-modules for the negative arm. The DC-voltage balance algorithm, the circulating-current reduction algorithm, the harmonic reduction algorithm, and the redundancy operation algorithm were included in this simulation model. The developed simulation model can be utilized to analyze the MMC-based BTB converter for HVDC application in switching level and to develop the protection scheme for the MMC-based BTB converter for HVDC application.

• YAKHAK HOEJI
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• v.39 no.3
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• pp.231-242
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• 1995

Electroconvulsive shock (ECS) increases the activity of acetylchohnesterase and decreases in brain acetylcholine levels. A large amount of free fatty acids accumulated in the brain tissue affects cerebral blood flow, brain edema and inflammation and results in brain injury. The present study examined the effect of docosahexaenoic acid (DHA) and D,L-pyroglutamic acid (D,L-PCA) on the learning and memory deficit using the passive avoidance failure technique and on the change of acetylcholine and choline level in the cerebral cortex of ECS-induced mice. The application of ECS (25mA, 0.5sec) induced a significant decrease in memory function for 30 min. ECS-induced a significant decrease in cortical acetylcholine and choline levels 1 min following the ECS application, which were almost recovered to ECS control level after 30 min. DHA (20 mg/kg, i.p.). administered 24 hr before shock. prevented the ECS-induced passive avoidance failure and the decrease of acetylcholine level 1 min following the ECS application. DHA failed to elicit a change in cortical choline level. DHA did not affect memory function and the cortical Ach and choline level of normal mice. The administration of D,L-PCA (500 mg/kg, i.p.) increased the effect of DHA on memory function and the change of cortical acetylcholine level of ECS induced mice. These results suggest that DHA treatment may be contributed to the prevention against memory deficit, and to the activation of cholinergic system in the ECS induced mice.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.77-82
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• 2006

Integrity plays a fundamental role in the feasibility of 'liability critical' applications. Road charging, e.g. road tolling in urban zones or on highways, represents a series of liability critical applications where a guarantee in integrity could be a true enabler: being the mechanism that prevents the incorrect charging of users and enabling the advancement of these applications using GNSS such as Galileo and EGNOS that provide integrity mechanisms. However, the integrity of the end user position is not guaranteed by the EGNOS and Galileo integrity services alone as provided. Algorithms have been developed to supply a guarantee on the performance attainable at the user level through the provision of a horizontal protection level that responds to local user conditions such as multipath or interference. In addition, an application has been developed that implements road charging mechanisms based on the availability of user-level integrity. Results obtained show that the user-level integrity algorithms provided the required level of integrity guarantee and granularity of the horizontal protection levels necessary for executing urban and rural (highway) road charging. In addition, the road charging application developed shows that the current application domain requirements can be met through the provision of guaranteed integrity and that further reductions in the horizontal protection levels along with increased signal availability will enable future road charging modalities.

• Journal of Korean Academy of Nursing Administration
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• v.13 no.2
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• pp.191-198
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• 2007

Purpose: The aim of this study was to find the effect of collaborative learning on problem-solving processes according to the level of metacognition, after adopting collaborative learning to clinical practice of nursing management. Method: Senior college students participated in this study. 90 students who was involveled in high level metacognitive group and another 88 students in low level metacognitive group. The data was collected from 2003 to 2005. The process of collaborative learning was categorised in 4 steps. The data were analyzed using t-test, ANCOVA, paired t-test. Results: 'There will be a distinction between the low and high metacognition groups after application of collaborative learning' was rejected. 'In the high level metacognitive group, the problem-solving ability will also increase after application of collaborative learning than before application' was supported. 'In the low level metacognitive group, the problem-solving ability will increase after application of collaborative learning than before application' was supported. Conclusion: The results showed that with collaborative learning, the problem-solving ability of learners with different levels of metacognition is improved.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.4
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• pp.185-190
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• 2022

The article analyzes the impact of factors affecting the application of management accounting in Vietnamese small and medium enterprises. It provides more empirical evidence on the factors affecting the application of cost management accounting. The research methodology involved a questionnaire survey of managers at all levels, and chief accountants and accountants of 65 Vietnamese construction enterprises. 220 questionnaires were collected in total, out of which 14 invalid questionnaires were not used due to many blank cells. The 5-level Likert scale is familiarly used in many studies, so the author also quantifies each factor according to five levels. Quantitative research was carried out with SPSS 25 software. Research results show that 4 factors positively influence the application of cost management accounting, including Business strategy, Management cost control, level of accounting staff, and Manager's point of view on cost management accounting. The level of accounting staff factor has the strongest influence on the application. Based on the research results, the author has proposed recommendations to improve the application of cost management accounting techniques of construction enterprises, thereby contributing to enhancing competitiveness and efficiency activities of construction enterprises in Vietnam.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.10a
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• pp.158-169
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• 2004

Recently companies are aggressively pushing ahead with integrating the systematical applications of internal and external information systems such as Data level, Application level, Process level in the company, Process level between companies. The EAI solution is generally considered as the necessary tool to integrate companies, but the appraisal standard for the EAI solution has not yet settled in Korea, so the companies have difficulty in deciding whether to adopt the EAI solution or not. Through this report, we first introduce the KRA Project as the best practice in making an application of the settled standard to evaluate and adopt the EAI solution, and then suggest that it can be adapted to companies considering applying to the EAI solution.

• Korean Journal of Child Studies
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• v.27 no.3
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• pp.169-187
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• 2006

A hierarchical linear model(HLM) provides advantages over existing traditional statistical methods (e.g., ordinary least squares regression, repeated measures analysis of variance, etc.) for analyzing multilevel/longitudinal data or diary methods. HLM can gauge a more precise estimation of lower-level effects within higher-level units, as well as describe each individual's growth trajectory across time with improved estimation. This article 1) provides scholars who study children and families with an overview of HLM (i.e., statistical assumptions, advantages/disadvantages, etc.), 2) provides an empirical study to illustrate the application of HLM, and 3) discusses the application of HLM to the study of children and families. In addition, this article provided useful information on available articles and websites to enhance the reader's understanding of HLM.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.5
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• pp.280-289
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• 2003

The purpose of this study was to establish a model for recommendable application level of nitrogen fertilizer based on soil testing for summer chinese cabbage in highland. A field experiment was carried out with various nitrogen application levels in sand loamy soil with and without poultry manure compost. The application level of N in poultry manure compost plot was found to be $291kg\;ha^{-1}$ for maximum yield of chinese cabbage, and it was 87% of the required N application level, $335kg\;ha^{-1}$, for maximum yield of chinese cabbage in nonmanure plot. In the treatment of poultry manure, approximately $174kg\;ha^{-1}$ of N was required to obtain the same yield of chinese cabbage as the maximum yield obtained in the treatments without poultry manure application. Therefore, with poultry manure application, N application level can be reduced by 40%. Using these results, a new equation for N recommendation for chinese cabbage in highland soil was proposed. With the average organic matter content of $33g\;kg^{-1}$ in highland field, the application levels of N for chinese cabbage were in the range of $215-129kg\;ha^{-1}$, which means that 32.8-59.7% of current application amount of N fertilizer can be reduced.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.5
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• pp.13-27
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• 2009

This study focused on the analysis of residential satisfaction depending on the extent of the application of environmental-friendly elements on the outdoor space of the apartment complexes. The purpose of this study is to present the basic materials of the environmental-friendly outdoor space planning of residential complexes. The major findings of the study are as follows. First, the results of the comparative analysis of the satisfaction of the outdoor space of apartment complexes show that the complexes with the most application of environmental-friendly elements had higher residential satisfaction. But, there was no meaningful statistical difference between the complexes with the highest level of application of the environmental-friendly elements and the complexes with medium level of application. Secondly, according to a comparative analysis, the overall residential satisfaction of the apartment complex was the same as the residential satisfaction of the outdoor space. Therefore, the overall satisfaction of the apartment complex seems to be influenced by the satisfaction of the outdoor space. Thirdly, the results of the correlative analysis of the satisfaction of the apartment complex showed that the satisfaction of the apartment complex increases as the satisfaction of the outdoor space of the apartment complex increases. The results of this study can be used as the basic materials for environmental-friendly outdoor space planning of apartment complexes.

• Journal of KIBIM
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• v.7 no.2
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• pp.25-35
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• 2017

Building information modeling (BIM) can improve to communicate with project participants by early construction involvement (ECI) from the beginning of the project. Therefore, they can minimize design changes and improve design quality and construction. However, because there is insufficient research on the scope and application level of BIM according to project delivery system and project characteristics, construction companies have efficiently not been using the BIM. Therefore, this study intends to conduct basic research as a basis for confirming appropriate BIM application and level according to project delivery system and project characteristics. To do this, we investigated the project delivery system and project characteristics of domestic and foreign projects that have successfully applied BIM, and compare and analyze them based on BIM application and BIM level framework derived from theory reviews and experts. Therefore, this study can be used as a basis for strategically establishing the scope and level of BIM according to project delivery system and project characteristics through the result of this study.