• Journal of Practical Engineering Education
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• v.11 no.1
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• pp.61-73
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• 2019

Recently the Korean life-long occupational skill development system is undergoing rapid change and innovation on the basis of NCS (National Competency Standards). In order for the NCS-based occupational training system to be successfully established, it is required to be accepted and applied in the higher education. Universities, however, hesitate to adopt NCS-based contracted education programs of the work-and-study cooperative system due to low relevance of university education to industrial needs and absence of the reference operation model for the NCS-based contracted education programs considering Korean small companies' particular needs. This study aims to develop and apply a reference operation model for NCS-based contracted education programs of the university-linked work-and-study parallel system, focusing on the Department of Mechanical Design Engineering of College of Work and Study in Parallel, Koreatech. In addition, several operational guidelines are suggested within the framework of current law and regulations for successful diffusion of the NCS-based reference operation model. The results of this study are expected to contribute to nation-wide proliferation of NCS-based contracted education programs in the higher education and motivating companies and universities to participate in the work-and-study parallel initiatives.

• Journal of Practical Engineering Education
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• v.13 no.3
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• pp.507-514
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• 2021

K University of engineering college awarded degrees to workers for major of electrical and electronics in the degree-linked work-study parallel system for the first time in February 2020. In this study, the progressed process to the stage of producing group graduation works for graduates and completing the results in an engineering thesis system were presented. The questionnaire consisting of 39 questions was conducted with the subjects, and the results of the responses were compared and analyzed with the results of full-time students in the same major who graduated in the same year. Statistical analysis was attempted by dividing the five representative response questions by group, but the number of people in each group was less than 30, so the normality test of response results and statistical analysis by parametric methods were limited. However, it was judged that a one-sample t-test was possible. Focusing on this method, it was confirmed that there was a difference of 0.8 points or more between the groups on an average 5-point scale in response items related to the number of changes in the subject of the work, the satisfaction among the members, and the effort to guide the work. And the measures to deal with these differences were suggested.

• Journal of Power Electronics
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• v.15 no.2
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• pp.327-337
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• 2015

This study discusses the design of a parallel-operated DC-DC single-ended primary-inductor converter (SEPIC) for low-voltage application and current sharing with a constant output voltage. A coupled inductor is used for parallel-connected SEPIC topology. Generally, two separate inductors require different ripple currents, but a coupled inductor has the advantage of using the same ripple current. Furthermore, tightly coupled inductors require only half of the ripple current that separate inductors use. In this proposed work, tightly coupled inductors are used. These produce an output that is more efficient than that from separate inductors. Two SEPICs are also connected in parallel using the coupled inductors with a single common controller. An analog control circuit is designed to generate pulse width modulation (PWM) signals and to fulfill the closed-loop control function. A stable output current-sharing strategy is proposed in this system. An experimental setup is developed for a 18.5 V, 60 W parallel SEPIC (PSEPIC) converter, and the results are verified. Results indicate that the PSEPIC provides good response for the variation of input voltage and sudden change in load.

• Journal of Practical Engineering Education
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• v.11 no.1
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• pp.51-59
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• 2019

This study includes the possibility of organizing courses that can accommodate both NCS-based and course-based qualifications program in terms of contracting departments operating a college-based work and study in parallel system, examining and comparing differences between the two qualifications. Based on the case study of mechanical design engineer based on the job of machine design, curriculum that meets both composition regulation is developed. The author predicts future operational differences and problems and suggests several ways to overcome them. In conclusion, a few words have been added to modify the composition regulations to help the professional educational institute that simultaneously operates a work parallel system and a course evaluation type as to develop the field-oriented curriculum minimizing the gap between provider-centered education and consumer-centered qualifications, and maximizing the performance of training and education.

• International Journal of Advanced Culture Technology
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• v.10 no.4
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• pp.245-254
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• 2022

This study is a study to empirically verify the mediating effect on college life adaptation and career preparation behavior of college students. The purpose of this study is to empirically analyze the multi-mediated effects of major satisfaction, job stress, and self-directed learning. For this study, 216 university students were enrolled. For the collected data, SPSS Process macro was used. The result is as follows. First, there were multiple parallel mediating effects and multiple serial mediating effects on major satisfaction, job stress, and self-directed learning between college life adaptability and career preparation behavior. Second, the path of simple mediation and double mediation effect was found between college life adaptation and career preparation behavior. Based on the research, the necessity of revitalizing the program for revitalization of teaching activities and industry-academic cooperation activities in the major field and improvement of career preparation behavior and university life adaptation ability and follow-up research were suggested.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.9
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• pp.753-760
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• 2006

The purpose of the present work is to investigate the influence of the refrigerant adulteration by LiBr solution on the cooling capacity and COP for three different types of abso게tion chillers: a single-effect type, a series-flow double-effect type and a parallel-flow with double-effect type. A simulation program has been prepared for the cyclic analysis of absorption chillers. With some assumptions, the calculations have been performed by solving the mass balance equation, energy balance equation and the state equation simultaneously. The range of the LiBr concentration of refrigerant was 0% to 20% in the present study. For the single-effect absorption chiller, the maximum decrease in the cooling capacity was 10% at the 20% of LiBr concentration. For the double-effect chiller, the capacity was decreased by 11.1% for the parallel-flow type and the series-flow type. Also, the COP was reduced by 3.0% in single-effect, 2.8% in series-flow type (SR=0.4) and 2.3% in parallel-flow type.

• Safety and Health at Work
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• v.13 no.3
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• pp.286-293
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• 2022

Background: The death rate of workers due to industrial accidents in South Korea (3.61 persons in 2017) is higher than the Organization for Economic Cooperation and Development average (2.43) and the fifth highest among Organization for Economic Cooperation and Development member countries. Although the pandemic of novel coronavirus (COVID-19) has changed, the socioeconomic aspects of Korean society, the number of Koreans suffering accidents and the number of deaths in 2020 have increased. It is necessary to take measures to prevent accidents and make comprehensive efforts to return to work. This study proposes research questions about the effect of workers' positive perception on whether to work after accidents and the impact of the experience of rehabilitation services on the return to work. Methods: This research performed a panel logistic regression analysis using data on workers' compensation insurance in Korea for two years (2018-2019). Results: This research finds that workers' positive perceptions of workability and life satisfaction contributed affirmatively to their re-employment. Several factors related to employment (e.g., work period, the number of job qualifications) also positively affect their return to work. However, the experience of rehabilitation services did not have a significant effect on re-employment. The variables of their health conditions (e.g., disability grade, feelings of health problems, age) negatively influenced their return to jobs. Conclusion: These results suggest the importance of workers' mental recovery and the need to innovate rehabilitation services for their employment. Positive thinking and self-rehabilitation could be critical for workers, parallel with social welfare policies.

• International Journal of Reliability and Applications
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• v.14 no.1
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• pp.11-26
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• 2013

The availability equivalence factors of a general repairable series-parallel system is discussed in this paper based on the availability function of the system. The system components are assumed to be repairable and independent but not identical. The life and repair times of the system components are exponentially distributed with different parameters. Two types of availability equivalent factors of the system are derived. The results derived in this paper generalizes those given in the literature. A case study is introduced to illustrate how the idea of this work can be applied.

• Human Ecology Research
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• v.58 no.3
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• pp.333-341
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• 2020

This study examined the trajectories of the marital satisfaction among middle and old aged couples for 8 years. This study focused on middle and old aged couples who were relatively uninterested in family research. Using the 1-5 Waves of Korean Longitudinal Study of Ageing (KLoSA) 2006-2014, the study included 635 middle and old aged couples whose husbands were 65-74 years old at baseline. First, a latent growth model indicated that a husband's and wife's marital satisfaction trajectories decreased over time. Second, a parallel latent growth model indicated that a husband's marital satisfaction trajectories decreased more quickly, when the initial level of their own marital satisfaction was higher (husband's actor-effect); in addition, a wife's marital satisfaction trajectories also decreased more quickly, when the initial level of their own marital satisfaction was higher (wife's actor-effect). Wife's marital satisfaction trajectories decreased more slowly, when the initial level of their husband's marital satisfaction was higher (husband's partner-effect); however, the husband's slope was not associated with the initial level of their wife's. The methodological value of this work shows the application of a parallel latent growth model that includes the actor and partner effect of APIM. The findings extend our understanding of longitudinal marital dynamics between couples and promote a study on the trajectories of marital satisfaction at stages of the family life cycle.

• Smart Structures and Systems
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• v.11 no.1
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• pp.35-51
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• 2013

Over the last two decades Wavelet Transformation (WT) method has been widely utilized for the damage identification of structures. The main objective of this paper is to discuss and present some of common shortcomings and limitations of mathematical software, as well as other precautionary measures that need to be considered when using them for wavelet analysis applications. Due to popular usage of MATLABMATLAB(R) comparing to other mathematical tools among researchers for data processing of structural responses through WT analysis, this software was chosen for specific study. To the best of the authors' knowledge, these limitations and observations have not been previously identified or discussed in the literature. In this work, a square plate with a severe damage, in form of a crack, parallel to the left edge of the plate is selected for a pilot study. The steady state harmonic response is used for measuring the deflection shape across the line parallel to one edge and perpendicular to the damage. Several criteria and cases such as the smallest size damage that can be detected, correlation between the crack width and the number of sampling points, and the influence of the damage thickness on the accuracy of the result are investigated.