• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.8
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• pp.107-114
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• 2017

In this paper, a novel power factor compensation system based on voltage-controlled method is proposed for 3-phase 4-wire power system. The proposed voltage-controlled power factor compensation system generates a reactive power required for compensation by applying a variable output voltage by a slidac to a capacitor. In conventional power factor compensation system using the capacitor bank method, the power factor compensation error occurs depending on the load condition due to the limited capacity of the capacitors. However, the proposed system compensates the power factor up to 100% without error. In this paper, we have developed a voltage-controlled power factor compensation system and a control algorithm for 3-phase 4-wire power system, and verify its performance through simulation and experiments. If the proposed power factor compensation system is applied to an industrial field, a power factor compensation performance can be maximized. As a result, it is possible to reduce of electricity prices, reduce of line loss, increase of load capacity, ensure the transmission margin capacity, and reduce the amount of power generation.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.5
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• pp.337-343
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• 2014

This paper presents a continuum-based shape design sensitivity analysis(DSA) method for crack propagation problems using a reproducing kernel method(RKM), which facilitates the remeshing problem required for finite element analysis(FEA) and provides the higher order shape functions by increasing the continuity of the kernel functions. A linear elasticity is considered to obtain the required stress field around the crack tip for the evaluation of J-integral. The sensitivity of displacement field and stress intensity factor(SIF) with respect to shape design variables are derived using a material derivative approach. For efficient computation of design sensitivity, an adjoint variable method is employed tather than the direct differentiation method. Through numerical examples, The mesh-free and the DSA methods show excellent agreement with finite difference results. The DSA results are further extended to a shape optimization of crack propagation problems to control the propagation path.

• Journal of dental hygiene science
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• v.14 no.4
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• pp.554-562
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• 2014

This study was conducted to identify the factors influencing toothbrushing behaviors of elementary school students by adding the variable of 'self-efficacy' to the behavioral model based on the theory of planned behavior. To collect the data for an analysis, the self-administered questionnaire was distributed to 443 students in 4th to 6th grades of elementary school placed in Inchon Metropolitan City. The statistical package of PASW 18.0 was employed for the analysis. Results of the analysis revealed that the toothbrushing intention was explained by the subjective norm (${\beta}=0.343$), the self-efficacy (${\beta}=0.171$), the perceived behavioral control (${\beta}=0.163$), and the attitude toward the tooth-brushing behavior (${\beta}=0.135$). The toothbrushing behavior was explained by the toothbrushing intention (${\beta}=0.355$) and the self-efficacy (${\beta}=0.113$). The synthesis of such results suggested that both parents and teachers in school who would be influential to students should guide elementary school students to be habituated to the right toothbrushing. Also it was estimated that the students should understand the importance of toothbrushing through proper oral health education, and they should also become confident in spontaneous toothbrushing by providing them with an environment that could help them practicing the toothbrushing easily.

• Korean Journal of Social Welfare
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• v.63 no.2
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• pp.261-289
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• 2011

This study has been conducted to assess the effectiveness of the elderly employment programs through change of social capital by understanding how the elderly employment programs in the elderly employment policy of Korea has effected the change of social capital. The method of research was to design the research in the nonequivalent control groups design from the quasi-experimental design for the 500 elderly who participated and 250 who have not participated in the elderly employment programs through distributing structured questionnaire by classifying into before and after the project during 7 months from March 1, 2010 to September 30, 2010 to those above 65 living in Changwon. The social capital which is an important variable among the measurement index of the study has been set as trust, network, and social participation fields based on the aforementioned theoretic background. When the fact that there is a partial difference in the change of social capital of the elderly according to the participation in the elderly employment programs and the timing (before/after) is looked at in terms of change of social capital after controlling the general character of the elderly and the pre-score, there are differences per timing according to the participation in the elderly employment programs. Thus, the participation in the elderly employment programs had a significant difference in the change of social capital. It is possible to see that the trust, network, and social participation of the social capital all increased in the elderly with difficulties in their living status. It can be seen that the participation in the elderly employment programs brings forth increase of social capital for the elderly with difficulties in their living status. Among the social capitals, the elderly who participated in the elderly employment programs showed that the trust increased the most. Consequently, in order to increase the comprehensive social capital, the programs must be carried out focused on the vulnerable class in parallel to the elderly employment programs for the general elderly of other classes.

• Journal of the Korea Concrete Institute
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• v.26 no.3
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• pp.351-360
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• 2014

The purpose of this research is to introduce the simplified equivalent frame model for the equivalent lateral force procedure, the response spectrum procedure and nonlinear procedure according to ASCE7-10 in order to reduce the time of performance and reasonably evaluate the effect of applying the damping system with the various conditions for the analysis and the variable. In this research, the seismic performance assessment and the design of the damping system were conducted through the nonlinear time history analysis based on the performance based seismic design in ASCE7-10 in regard to applying the damping system to apartment buildings which is lately issued. The optimal design based on the 75% of seismic base shear was performed for an apartment building. The seismic performance assessment were conducted to check the safety of the building, and the economic evaluation was performed by comparing the amount of resource for the optimal designed building with the amount of resource for the original building. In addition, hysteresis dampers was applied to the apartment building, and the suggested equivalent frame model was performed using the damping system design in ASCE7-10, then its control effects were proved in the full scale model of the apartment building which was used in this research.

• Journal of Information Technology Applications and Management
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• v.20 no.1
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• pp.43-51
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• 2013

Human being does work to live out and they have their private life because human has sociality. Both work and life are important to live out but they are on the trade-off relationship. Because keeping the balance between work and life is too hard, it has been interested by academic and practical areas. Definition of Work-life balance here is that balance or imbalance arising between work and life has no negative impact on their daily life. Above all, Work-life balance is important because it is strongly related to identity. Recently, the introduction of the mobile office system has emerged as a way to solve the problem of work-life balance. It is based on the teleworking which was formerly generated. Teleworking is to perform the work in the employee's home or office space set aside without going into the workplace. Concept of the mobile office system here is not only using portable devices during work for convenience but also the system which is designed for the performance. Thanks to the diffusion of smart devices(smart phone, tablet pc), mobile office system has been spread. Although the importance of mobile office systems is emerging, there are few researches about it. Even they mostly focus on the standpoint of performance of mobile office system. However, Quality of life is as important as the performance. As a part of Quality of Life field, Work-life balance is the closest to employee's quality of life. So this study aims to examine the effect of the use of mobile office systems on work-life balance. To do so, we try to find factors effecting Work-life balance from existing studies and then set a research model. We set the use of mobile office systems as independent variables which are divided by use of function, use by location and use by situation. There are four dependent variables - sense of self command, sense of balance, solving work problem, solving life problem. We collected data from employees who are using mobile office systems on their job. 215 people were participated in the survey and we used multiple regression analysis to verify our research model. Results show that every independent variable has no impact on solving work problem while they have slight impact on the other dependent variables. Especially use on the business trip has significant effect on dependent variables. It means that there is a possibility use of mobile office system could control the employee's quality of life and system should be evolved until it covers even critical tasks. Also, support for mobile office system -education, encouragement-should be provided. By mobile office system is maturing, future research would be done.

• 한국초등상담교육학회:학술대회논문집
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• 2004.01a
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• pp.205-222
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• 2004

Fundamental direction of the seventh education curriculum aims to nurture active and creative Koreans for globalized and information-oriented society of 21 century, and emphasizes the importance of career education identifying its subsections that are practices of student-focused education of aptitude, ability and career. Hence, as a clear targeting of career objective from elementary school through relevant career education enables them to recognize appropriate career for themselves, the basis of self- actualization and social contribution must be settled. This paper seeks to identify the relationship between career awareness and self-esteem by examining and analysing differences of sex, region and level. This study selected 536 samples from 4th and 6th year elementary school students in C city and S town of Chungcheong province. Career awareness test and self-esteem test is used as a measurement, statistical process control (SPC) of career awareness and self-esteem (M, SD, r) is made for each variable, and the significance was tested. The result of this research can be summarized as follows: First, generally there is very significant regional differences of career awareness (F=16.817, p<.001), which contains that urban children has higher career awareness (M=120.22) than that of rural children (M=113.87). In subsections of career awareness, self-esteem of urban children is higher than that of rural children, and the attitude & for career and values of girls is higher than that of boys. In terms of the career planning, urban children and 6th year students are higher than rural children and 4th year students. Second, self-esteem generally has very significant regional difference (F=12.123, p<.01), which contains that the self-esteem of urban children (M=106.50) is higher than that of rural children (M=101.80). In comparison of different forms, a very significant difference is as much as p<.01 level (F=11.046), which contains 4th year students (M=105.63) have higher self-esteem than 6th year students (M=102.05). In subsections of self-esteem, gross self-esteem and social self-esteem of urban children are higher than rural children. In terms of family self-esteem, urban children and 4th year students have higher figure than rural children and 6th year students. In school self-esteem, 4th year students had higher level than the 6th. Third, the career awareness and self-esteem are generally related as r= .50, it was very significant at p<. 001 level. All subsections of career awareness had positive relationships except the school self-esteem. According to the result, rural children had relatively low career awareness and self-esteem. This is presumably due to relatively poor circumstances for rural children, comparing to that of urban children. Therefore rural elementary schools should try to let them have appropriate career awareness by associating with family, school and local society to expand the opportunity of experiences for the self perception of aptitude, nature and interest. In addition, we have to strive for the whole-minded education increasing the self-esteem of rural children and giving them positive thinking through career counselling, personal counselling and group counselling.

• Journal of Acupuncture Research
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• v.19 no.6
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• pp.111-124
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• 2002

A line of study reported that electroacupuncture(EA) modulate natural killer cell(NK Cell) activities. One report suggested that EA enhanced splenic interferon-gamma($IFN-{\gamma}$), interleukin-2(IL-2), and NK cell activity in Sprague-Dawley rats. Another study suggested that $IFN-{\gamma}$ mediates the up-regulation of NK cell activity, and endogenous ${\beta}$-endorphin secretion also play a role in the up-regulation of NK cell activity induced by EA stimulation. In order to better understand the molecular regulation underlying the activation of NK cell induced by EA, we have utilized cDNA microarray to elucidate how EA alters program of gene expression of spleen in rats. First, we divided three groups, group I was EA group treated with EA in restriction holder, group II was sham group with only holder stress, and last group III was control group with no treatment. We measured NK cell activity after EA stimulation three times for 2 days using $^{51}Cr$ release assay. Second, Biotin-labeled cDNA probes synthesized from EA group and sham group, were competitively hybridized to the microarray that contained variable genes. Such high-throughput screening has identified a number of EA-responsive gene candidates. Of these, we found that EA induced a subset of genes of genes that functionally could modulatory effects on NK cell activity. Genes(vascular cell adhesion molecule-1, protein-tyrosine kinase, CD94 mRNA) related to boost NK cell activity, were increased by EA And, genes(protein-tyrosine-phospatase mRNA, protein-tyrosine phosphatase(SHP-1) mRNA) related to inhibit NK cell activity, were decreased by EA. These EA-responsive genes may provide key insights from which to understand mechanisms of activation of NK cell induced by EA.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.12 no.3
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• pp.37-51
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• 2017

We investigated how entrepreneurship, information technology acceptance, and media utilization influence on office worker commitment and how effects are modulated by learning orientation. The purpose of this study is to identify variables that influence on office worker commitment. To do so, entrepreneurship, information technology acceptance, and media utilization that are the core competencies of individuals and organizations in the era of smart information are proposed as predictor variables, office worker commitment as a outcome variable and learning orientation as a modulator. For this study, a questionnaire survey was conducted on office workers, and finally 340 valid questionnaires are used for analysis. Hierarchical regression analysis is used with demographic characteristics as control variables and learning orientation as a modulating variables. A result showed that the higher need for achievement and proactiveness of entrepreneurship is, the higher job commitment is and that the perceived usefulness of information technology acceptance and communication utilization ability of media utilization competitiveness have a positive effect on job commitment. A research showed that learning orientation is modulating the relationship between entrepreneurship and job commitment, and between media utilization capability and job commitment, respectively. We concluded that we should actively seek synergies of learning orientation along with accumulation of online communication utilization capacity and perceived usefulness of information technology, and of proactiveness need for achievement and in entrepreneurship in order to improve the work committment in the smart information society where the digital environment is advanced.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.10
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• pp.1307-1313
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• 2011

The mechanical limited slip differential (LSD) in vehicles is being replaced by the electromagnetic LSD because of its fast response and better active control characteristics. The coil housing made of STS 304 is one of the most important parts in the solenoid assembly of the electromagnetic LSD. High geometrical accuracy is a prerequisite for the manufacture of such coil housings, but precision machining is difficult because of the use of STS 304 thin plate and the variance in machining variables. The aim of this study is to optimize the mean and variance of the shape accuracy in the coil housing by finding a robust solution for the machining process conditions. The mean and standard deviation of the jaw contact pressure, cutting speed, and feed rate are considered to be the major parameters for minimizing the geometrical mean and variance. The response surface model based on the second-order Taylor series is combined together to minimize the mean and variance of the shape accuracy of the coil housing.