• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.686-694
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• 2014

A power semiconductor device, usually used as a switch or rectifier, is very significant in the modern power industry. The power semiconductor, in terms of its physical properties, requires a high breakdown voltage to turn off, a low on-state resistance to reduce static loss, and a fast switching speed to reduce dynamic loss. Among those parameters, the breakdown voltage and on-state resistance rely on the doping concentration of the drift region in the power semiconductor, this effect can be more important for a higher voltage device. Although the low doping concentration in the drift region increases the breakdown voltage, the on-state resistance that is increased along with it makes the static loss characteristic deteriorate. On the other hand, although the high doping concentration in the drift region reduces on-state resistance, the breakdown voltage is decreased, which limits the scope of its applications. This addresses the fact that breakdown voltage and on-state resistance are in a trade-off relationship with a parameter of the doping concentration in the drift region. Such a trade-off relationship is a hindrance to the development of power semiconductor devices that have idealistic characteristics. In this study, a novel structure is proposed for the Insulated Gate Bipolar Transistor (IGBT) device that uses conductivity modulation, which makes it possible to increase the breakdown voltage without changing the on-state resistance through use of a P-floating layer. More specifically in the proposed IGBT structure, a P-floating layer was inserted into the drift region, which results in an alleviation of the trade-off relationship between the on-state resistance and the breakdown voltage. The increase of breakdown voltage in the proposed IGBT structure has been analyzed both theoretically and through simulations, and it is verified through measurement of actual samples.

• The Journal of the Korea Contents Association
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• v.9 no.6
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• pp.145-152
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• 2009

We are surrounded by so many images these days. These images have their own meanings and have an effect on our subject, whether consciously or unconsciously. Michel Foucault disclosed that upon closer examination the rationalism deeply rooted in Western society was not made autonomously but involuntarily by heteronomous power. Because the emotion of image within this relationship can be effectively conveyed just through its being seen, the image has been used for controlling and mustering people through the adjustment of its meaning by power. With the advance of technology and media of today, the image in this visual power is out of the object for reproduction, and then forms a new paradigm of manipulation, transformation and reproduction and is being changed to the formation of Panopticon power and its corresponding relationship.

• The Korean Journal of Ecology
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• v.27 no.1
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• pp.27-33
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• 2004

Cryptomeria japonica plantation was monitored every year during 15 years from 1983 to 1997 for stem diameter and volume. The reciprocal equation, 1/Y = A + B/N, was applied to the relationship between cumulative volume Y and cumulative number N from the largest tree in the stand each year. The parameters A and B, which means respectively the reciprocal of an asymptotic value of total stand stem volume and the reciprocal of the maximum stem volume, are related by a power function. The power functional relationship between A and B derived a linear relationship of B-points ( $N_{B}$, $V_{B}$; $N_{B}$ = B/A, $Y_{B}$ = 1/2A) of each Y-N curve on log-log coordinates. The gradient of B-point line was so steep that the Y-N curve moved parallel upward year by year. The time trajectory of mean stem volume (W) and density ($\rho$) provided evidence in favor of the 3/2 power law of self-thinning, because the gradient of W - $\rho$ trajectory on log-log coordinates approximated to -3/2 at the final stage of stand development. On the basis of the results of Y-N curves and W - $\rho$ trajectory, the time trajectory of maximum stem volume $W_{max obs}$ and $\rho$ was derived theoretically. The gradient of $W_{max obs}$ - $\rho$ trajectory on log-log coordinates is calculated to be -0.6105 at the final stage. The gradient of $W_{max obs}$ - $\rho$ trajectory was steeper than that of W - $\rho$ trajectory at the early stage, while the former is gentler than the latter at the later stage.stage.e.age.e.

• Korean Journal of Human Ecology
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• v.10 no.1
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• pp.127-139
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• 2001

The purpose of this study was to find out the relationships among the elderly's self-esteem and life-adjustment according to decision-making power in their family. Interview survey was conducted and were selected. 296 over age 60 who lived in Jeonju. Frequencies, Percentiles, Pearson's correlation, t-test, ANOVA and Duncan's method were utilized for data analysis. The findings of this study were as follows ; 1) Decision-making power of the elderly in family had significant differences according to sex, coresiding with married children, and the sum of monthly personal expenses. 2) Elderly's self-esteem had significant differences according to sex, the present job, the situation of a spouse, and the sum of the monthly personal expenses. 3) Elderly's life-adjustment had significant difference according to residence type, the present job, the situation of a spouse, religion, education, and the sum of the monthly personal expenses. 4) Clothing and food in family had significant differences according to sex. 5) The elderly men's self-esteem had positive relationship with housing, sons and daughters guidance, grandchildren care, and family event and etc. But the elderly women's self-esteem had positive relationship with food, grandchildren care, and family event and etc. 6) The elderly men's life-adjustment had positive relationship with clothing, food, housing, family economy, sons and daughters guidance, grandchildren care, and family event and etc. But the elderly women's life-adjustment had positive relationship with food, housing, sons and daughters guidance, grandchildren care, and family event and etc.

• Journal of the Korean Geotechnical Society
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• v.34 no.9
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• pp.43-49
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• 2018

Seismic hazard assessments are performed on a variety of infrastructure projects. One component of a seismic hazard assessment is the attenuation relationship. Several attenuation relationships have been developed over the decades to predict peak ground acceleration under a variety of site conditions. For example, many attenuation relationships were designed to estimate peak ground acceleration, as well as other intensity measures, under a variety of soil conditions, mostly using the average shear wave velocity for the upper 30 m of earth material as a classification scheme. However, certain types of infrastructure, such as tunnels and nuclear power plants, are typically founded on and in bedrock. Using data from Japan, we developed a simple correlation to estimate peak ground acceleration for rock sites and compare the results from another popular attenuation relationship. Results indicate the popular attenuation relationship to be less than the proposed model for distances less than 200 km.

• Korean Journal of Legislative Studies
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• v.15 no.1
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• pp.5-38
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• 2009

This study analyzes the relationship since 1988 between National Assembly, president and political parties in Korea, and to find critical conditions for developing a mutually beneficial relationship among them. It argues that the levels of both internal power concentration and cohesiveness(or discipline) of political parties matter greatly, and applies them as theoretical framework for the historical review. By 2002, major political parties were highly concentrated in power and their discipline was strong. Consequently parties fought collectively with each other and Assemblies repeatedly saw standoffs and deadlocks. Reforms of 2002-04 that sought higher degree of party democracy and more autonomy among members of National Assembly have not been able to bring in a productive legislative-president relationship. A cohesive faction politics under the leadership of (potential) presidential candidates keeps it from growing. This study suggests further democratization of party power and more autonomy to individual Assembly members.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.136.2-136.2
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• 2011

In this work, we analyzed correlations between life-cycle greenhouse gas (GHG) emissions and life-cycle cost of energy resources. Energy resources studied in this paper include coal, natural gas, nuclear power, hydropower, geothermal energy, wind power, solar thermal energy, and solar photovoltaic energy, and all of them are used to generate electricity. We calculated the mean values, ranges of maximum minus minimum values, and ranges of 90% confidence interval of life-cycle GHG emissions and life-cycle cost of each energy resource. Based on the values, we plotted them in two dimensional graphs to analyze a relationship and characteristics between GHG emissions and cost. Besides, to analyze the technical maturity, the GHG emissions and the range of minimum and maximum values were compared to each other. For the electric generation, energy resources are largely inverse proportional to the GHG emission and the corresponding cost.

• The Research Journal of the Costume Culture
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• v.18 no.3
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• pp.588-598
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• 2010

Purposes of this research were to examine characteristics of contractors and the relationship between contractors and wholesalers of apparel products. Influence of such variables on wholesalers' satisfaction was also assessed. Location, reputation and service were factors of contractor characteristics. Dependence, cooperation and power were three factors that were considered for contractor-wholesaler relationship variable. Survey data from 109 wholesalers located in Dongdaemun Fashion Town in Korea was used for analysis. Empirical results confirmed the importance of service factor of contractor characteristics. Service and location of the contractor had positive influence on cooperation. Location had negative influence on power. Reputation had positive direct influence on wholesaler satisfaction. Cooperation between contractors and wholesalers had significant influence on wholesaler satisfaction.

• Journal of the Korean Home Economics Association
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• v.46 no.8
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• pp.121-133
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• 2008

The purpose of this study was to decipher the BRQ (Brand Relationship Quality) Construct of fashion product consumers and to identify influencing variables. Consumption values of consumers, fashion product attributes and marketing communication instruments were investigated as affecting variables. A questionnaire was distributed to 350 women between the age of 20 and 50 living in Seoul and other metropolitan areas from Mar. 5 to Mar. 18, 2008. Collected data were analyzed by factor analysis, reliability, multiple regression, frequency and percentage using SPSS (Version 15,0) statistical Package. The results were as follows: Firstly, the BRQ Construct of fashion product consumers was proved to be composed of five factors; 'self-connective love', 'pursuing symbol', 'trust', 'intimacy', and 'knowledge'. Secondly, consumption values had a significant effect on the BRQ Construct and their explanatory power was 32%, 'Epistemic value' was the most significant variable affecting BRQ. 'Functional value' had a significant influence on some BRQ factors. Thirdly, explanatory power of fashion product attributes affecting BRQ was 45%. 'Aesthetic attribute' had significant effect on all BRQ factors, while 'functional attribute' showed significant effect on only 'pursuing symbol', 'trust', and 'intimacy'. Finally, marketing communication mixes showed 21% explanatory power and 'word of mouth' and 'display' among marketing communication mixes were found as the most influential variables affecting the BRQ Construct.

• Elastomers and Composites
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• v.54 no.4
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• pp.351-358
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• 2019

To evaluate the aging of a rubber pad in power window switch which is the part of a vehicle, the accelerated thermal aging test of rubber pad material is performed. Finite element analysis was performed using the nonlinear material constants of the rubber pad to calculate the operating force, and the Arrhenius relationship was derived from the aging temperature and time. The aging test was performed at 150, 180, 210, or 240 ℃ for 1 to 60 days. When the operating force of the rubber pad is changed by 10% from the initial value, the service life is expected to be 113 years, which is much longer than the life of the vehicle. This indicates that the aging life of the rubber pad is sufficiently safe and the operating force of the rubber pad during the life of the vehicle (20 years) was decreased by approximately 8.4%. By examining the correlation between the shear elastic modulus and operating force calculated from finite element analysis under each aging test condition, the changes in the operating force of the rubber pad and the shear elastic modulus showed good linear relationship. The aging life could be predicted by the change in shear elastic modulus and a process for predicting the aging life of automotive power window switch rubber pad parts is described herein.