• Proceedings of the KAIS Fall Conference
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• 2003.06a
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• pp.267-270
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• 2003

All artificial infernal organs which are using electric energy supply energy with inductive couple. Transcutaneous energy transmission system enhance survival chance of the patients and quality of life by reducing volume and mass. In this research, we used both tune in transmission system in state of fixing cycle in order to increase the voltage gain and the current gain and to reduce effect of leakage inductance. Also to maximize the effect of resonance, a constant frequency duty cycle control method is used. Test is progressed with litz wire which is set up with various sizes of core to minimize size of converter. This research aimed in analysis of transcutaneous energy transmission system and in measuring of stability and efficiency of Lithium-ion battery charge which are using transmitted energy.

• Educational Technology International
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• v.24 no.2
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• pp.115-141
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• 2023

The aim of this research is to understand the perceptions of primary and secondary teachers regarding educational resource sharing systems(ERS) by using a qualitative approach. This study conducted Focus Group Interview(FGI) with 20 primary and secondary school teachers. Interview data were analyzed through inductive content analysis method. The results are as follows. First, teachers placed significant emphasis on high-quality, convenient functions, and reward system for sharing resources. Specifically, teachers identified the necessity for a diverse array of materials, systematic categorization of these resources, and the provision of monetary compensation as essential components. Second, the study participants advocated strategies for revitalizing ERS including enhancing accessibility, constructing user-friendly features, increasing awareness, and establishing a reward system to incentivize the resource sharing. In particular, teachers proposed strategies such as developing mobile-based services and AIdriven data recommendation system. These results provide actionable insights for stakeholders engaged in the design, implementation, and evaluation of resource sharing platforms.

• Journal of Power Electronics
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• v.18 no.4
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• pp.1268-1277
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• 2018

A relatively high operating frequency is required for efficient wireless power transfer (WPT). However, the alternating current (AC) resistance of coils increases sharply with operating frequency, which possibly degrades overall efficiency. Hence, the evaluation of coil AC resistance is critical in selecting operating frequency to achieve good efficiency. For a Litz wire coil, AC resistance is attributed to the magnetic field, which leads to the skin effect, the proximity effect, and the corresponding conductive resistance and inductive resistance in the coil. A numerical calculation method based on the Biot-Savart law is proposed to calculate magnetic field strength over strands in Litz wire planar spiral coils to evaluate their AC resistance. An optimized frequency can be found to achieve the maximum efficiency of a WPT system based on the predicted resistance. Sample coils are manufactured to verify the resistance analysis method. A prototype WPT system is set up to conduct the experiments. The experiments show that the proposed method can accurately predict the AC resistance of Litz wire planar spiral coils and the optimized operating frequency for maximum efficiency.

• Journal of Power Electronics
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• v.19 no.5
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• pp.1087-1098
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• 2019

In this paper, a detuning factor (DeFac) method is proposed to design the key parameters for optimizing the transfer power and efficiency of an Inductively Coupled Power Transfer (ICPT) system with primary-secondary side compensation. Depending on the robustness of the system, the DeFac method can guarantee the stability of the transfer power and efficiency of an ICPT system within a certain range of resistive-capacitive or resistive-inductive loads. A MATLAB-Simulink model of a ICPT system was built to assess the system's main evaluation criteria, namely its maximum power ratio (PR) and efficiency, in terms of different approaches. In addition, a magnetic field simulation model was built using Ansoft to specify the leakage flux and current density. Simulation results show that both the maximum PR and efficiency of the ICPT system can reach almost 70% despite the severe detuning imposed by the DeFac method. The system also exhibited low levels of leakage flux and a high current density. Experimental results confirmed the validity and feasibility of an ICPT system using DeFac-designed parameters.

• Research in Community and Public Health Nursing
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• v.16 no.3
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• pp.270-281
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• 2005

Purpose: The objective of this study was to understand the caring experience of families with terminal cancer patients. Method: This was designed to be an inductive and descriptive study. Forty-seven families with terminal cancer patients were interviewed in depth and collected data were examined through content analysis. Result: The main categories of difficulties found in this study were 'suffering of patient', 'emotional suffering of family', 'bereavement of patient', 'difficulties in coping', 'problems in treatment', 'incurable situation', 'family problems', 'relationship with other people', 'economic problems', 'spiritual problems', 'problems in the future', 'informing patients of their condition', 'preparing death', 'emotional unstability', 'meaninglessness', 'unkindness of medical teams', 'poor environment for treatment', 'difficulties in hospital environment' and 'economic burden'. Conclusion: The main point found from this result was that families taking care of terminal cancer patients are suffering emotionally from watching the patients' pains and had difficulties in coping with the patients' situation and treatment. In addition, they had negative experiences in medical teams' attitude and hospital environment. This result can be used as an important guide for nurses to assess families' needs in the terminal care setting.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.182-182
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• 2012

Plasma etching is used in various semiconductor processing steps. In plasma etcher, optical- emission spectroscopy (OES) is widely used for in-situ endpoint detection. However, the sensitivity of OES is decreased if polymer is deposited on viewport or the proportion of exposed area on the wafer is too small. Because of these problems, the object is to investigate the suitability of using plasma impedance monitoring (PIM) and self plasma optical emission spectrocopy (SPOES) with statistical approach for in-situ endpoint detection. The endpoint was determined by impedance signal variation from I-V monitor (VI probe) and optical emission signal from SPOES. However, the signal variation at the endpoint is too weak to determine endpoint when $SiO_2$ and SiNx layers are etched by fluorocarbon on inductive coupled plasma (ICP) etcher, if the proportion of $SiO_2$ and SiNx area on Si wafer are small. Therefore, modified principal component analysis (mPCA) is applied to them for increasing sensitivity. For verifying this method, detected endpoint from impedance monitoring is compared with optical emission spectroscopy.

• Journal of Industrial Convergence
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• v.21 no.10
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• pp.47-56
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• 2023

The purpose of this study was to explore educational awareness and meaning by applying an role-playing game (RPG) type class based on constructivism in physical education class in middle school. Regarding the research method, data collection was conducted through in-depth interviews, observations, and related documents, and data analysis was performed using case record analysis, inductive category analysis method, and case extraction process. Results of the study First, in terms of teachers' perceptions, there are both positive and negative aspects of teachers' perceptions of middle school physical education classes using the role-playing game (RPG) format. Second, in terms of educational meaning, the educational meaning of middle school physical education classes using the role-playing game (RPG) format emphasizes the need for a systematic lesson plan and sufficient support system. In conclusion, positive attitudes toward physical education as well as educational implications can be formed, and the basic foundation of the constructivist physical education class method and its preparation are thought to be of greater significance than anything else.

• Journal of Power Electronics
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• v.18 no.4
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• pp.1178-1189
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• 2018

In grid-connected voltage-source inverters (VSIs), when compared with a simple inductive L filter, the LCL filter has a better performance in attenuating the high frequency harmonics caused by the pulse-width modulation of power switches. However, the resonance peaks generated by the filter inductors and capacitors can make a system unstable. In terms of simplicity and filter design cost, a passive damping method is generally preferred. However, its high power loss and degradation in high frequency harmonic attenuation are significant demerits. In this paper, a mathematical design solution for a passive LCL filter to derive filter parameters suppressing the high frequency current harmonics to 0.3% is proposed. The minimum filter inductance can be obtained to reduce the size of the filter. Furthermore, a minimum damping resistance design considering a current controller is analyzed for a stable closed-loop system. The proposed design method is verified by experimental results using a 5-kW three-phase prototype inverter.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.8
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• pp.1-9
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• 2007

Characteristics of electrodeless lamp as a load of the ballast are different compared to normal fluorescent lamp because the lame includes an inductance due to coupling magnetics for inductive discharging process. This increased parameter makes the development of self-oscillation type ballast more complex and time consuming. Practical simulation method for an easy design of self-oscillation type ballast especially for Endura lamp, is presented by using a model and various analysis of simulation. Results of experiment are given for a verification of proposed method.

• Korean Institute of Interior Design Journal
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• no.38
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• pp.21-29
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• 2003

This study began to classify the studies on 'culture' in the field of environmental design overall. The classifying process adopted not the approach to preselect the criteria but the phenomenological inductive approach and content analysis method focusing on environmental design in order to understand which place the environmental design had taken. As a result, following aspects were reviewed: what is the area in which the studies on culture is made under the environmental design; what is the trend of using the word 'culture' in terms of logical connection; what is the level of approach to culture from the viewpoint of search, correspondence or application stage. On the whole, followings were drawn as conclusions. First, the interest of the studies on culture has been increased with time especially in the field of interior design. Second, the word 'culture' has become to be used a lot as 'cultural', and was used together with traditional, enterprise and material. Lastly, culture was studied at a starting point by and large. Although the papers, the objects of this study, are confined to five kinds of journals, the analysis of them is helpful to preestimate the trend of studies on culture because they have propensity to lead the international professional academic world.