• Journal of Korean Society for Quality Management
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• v.34 no.1
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• pp.1-12
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• 2006

This paper presents a six sigma project for improving gate painting quality in a medium-sized automotive part company. The project follows a disciplined process of five macro phases: Define, Measure, Analyze, Improve, and Control. A CTQ(critical to quality) is determined based on COPQ(cost of poor quality) analysis, and a process map is utilized for identifying process input variables. Three KPIV s(key process input variable) are selected; Painting Temperature, Painting Quantity, and Painting Viscosity, and DOE(design of experiments) is utilized for finding the optimal process conditions for three KPIVs. MINITAB software is used for data analyses and DOE. The sigma level of defects rate has improved from 2.93 to 3.66.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2001.11a
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• pp.3-11
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• 2001

Fundamental studies at the CSIRO division of Wool technology and ICI on the diffusion of dyes into wool〔1,2〕have let to development of a new approach to wool dyeing. In this method, the cell membrane complex of wool is modified before dyeing by treatment under mildly alkaline conditions with a special chemicals. Wool pretreated with ethoxylated quaternary ammonium salt has an increased rate of dyebath exhaustion and dye penetration early in the dyeing cycle. This enables the treated material to be dyed below the boil for a similar time to the conventional cycle. This technique can be used on untreated and shrinkresist-treated wool and wool/nylon blends. In addition to good macro-levelness and excellent coverage of tippiness, the low temperature dyeing process give higher exhaustion levels of dyestuffs and insect-resist agent and hence cleaner effluent liquors, compared with conventional dyeing process. Low Temperature Dyeing process cause significantly less fiber damage than conventional way. The reduction in damage is reflected in improved processing performance of the dyed wool.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.3
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• pp.159-165
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• 2021

This study introduces a topology optimization method for the simultaneous design of macro-scale structural configuration and unit structure variation to ensure effective heat conduction. Shape changes in the unit structure depending on its location within the macro-scale structure result in micro- as well as macro-scale design and enable better performance than using isotropic unit structures. They result in functionally graded composite structures combining both configurations. The representative volume element (RVE) method is applied to obtain various thermal conductivity properties of the multi-material based unit structure according to its shape change. Based on the RVE analysis results, the material properties of the unit structure having a certain shape can be derived using machine learning. Macro-scale topology optimization is performed using the traditional solid isotropic material with penalization method, while the unit structures composing the macro-structure can have various shapes to improve the heat conduction performance according to the simultaneous optimization process. Numerical examples of the thermal compliance minimization issue are provided to verify the effectiveness of the proposed method.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.5 no.4
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• pp.79-85
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• 2006

Multi-filament hydrostatic extrusion was developed as a fine wire manufacturing process and wire forming experiments were conducted. Also, single wire stretch forming process was proposed in the possibility of obtaining long wire with constant cross-section. In the multi filament extrusion since the workpiece, die and forming facility are in the macro forming circumstance, fine wire and fine hole structure with less than a few micrometer can be easily obtained. Although stretch forming does not use a die in order to avoid the friction problem between the workpiece and the die, it is necessary to have high level of technology to maintain cross-sectional shape and measure in longitudinal direction.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.309-317
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• 2012

Recent years have witnessed the use of micro shock tube in various engineering applications like micro combustion, micro propulsion, particle delivery systems etc. The flow characteristics occurring in the micro shock tube shows a considerable deviation from that of well established conventional macro shock tube due to very low Reynolds number and high Knudsen number effects. Also the diaphragm rupture process, which is considered to be instantaneous process in many of the conventional shock tubes, will be crucial for micro shock tubes in determining the near diaphragm flow field and shock formation. In the present study, an axi-symmetric CFD method has been applied to simulate the micro shock tube, with Maxwell's slip velocity and temperature jump boundary conditions. The effects of finite diaphragm rupture process on the flow field and the shock formation was investigated, in detail. The results show that the shock strength attenuates rapidly as it propagates through micro shock tubes.

• Journal of Convergence for Information Technology
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• v.10 no.9
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• pp.136-146
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• 2020

In order to verify that the ego-resiliency regulates the effect of nursing care workers job stress on the job satisfaction, this research ascertained the effect of job stress of the nursing care workers working at Seoul-type Day Care Center and confirmed the moderating effect of ego-resiliency on the process where nursing care workers job stress affects the job satisfaction. A survey of 256 employees at 28 Seoul-type Day Care Centers were conducted on job stress, job satisfaction, and ego-resiliency, and 138 nursing care workers were analyzed. The data analysis was conducted using SPSS PROCESS Macro, which was presented by SPSS 25.0 and Hayes. The results of the study are as follows. First, nursing care workers had higher job stress and lower job satisfaction compared to other job groups. Second, job stress identified the negative effect job satisfaction. Third, ego-resiliency confirmed positive moderating effect between job stress and job satisfaction.

• Information Systems Review
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• v.7 no.2
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• pp.117-128
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• 2005

This study proposes an integrated monitoring system for data reliability improvement in a steel manufacturing industry. The data obtained from existing steel manufacturing process is not micro data which is gathered at the occurring point, but average value (macro data) which is gathered from the occurring point to ending point. This kind of macro data is not only difficult for a detailed analysis for an error causing factor, but it might cause a fatal influence as well on the quality of produced goods even if the error is within an error tolerance. And during the process of steel production, thousands of data is produced in a second, thus requiring database plan to manage abundant amount of data. Therefore, the following proposed system is capable of collecting as well as analyzing all the data generated from the process of product production. And the system was able to raise the efficiency of the database server by planning the database to handle large capacity data. Also, by applying web-based technology, inquiries and analysis of data with no limit on time and space was possible with PC connected to the intranet. Hence, the system was able to work on effective quality improvement of manufactured products, plus able to raise the reliability of the product. Also, accumulated data from long period of time was used for fundamental material for new controlling model, operation technology, and new product development.

• International Journal of Advanced Culture Technology
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• v.8 no.3
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• pp.106-113
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• 2020

This study analyzed the impact of leisure activities on school life satisfaction in the cultural rights and self-determination of teenagers who spend most of their time in school in the college entrance exam-oriented climate, and examined the effects of happiness and life satisfaction on the school life satisfaction through a process macro applying Bias Corrected Bootstrapping in these relationships. For research purposes, 2,590 cohorts in the first year of the 2018 Korea Children and Youth Panel Survey were analyzed through process macros. The result was that leisure life had a significant effect on school life satisfaction. It was also found that happiness and satisfaction in life affect satisfaction, and happiness and satisfaction in life affect satisfaction in school life and serve as a medium. This study confirmed that teenagers' participation in leisure activities greatly affects school life satisfaction and that happiness and life satisfaction have a mediating effect on school life satisfaction. In addition, we could recognize the importance of leisure activities to the satisfaction of school life of teenagers, and find it necessary to develop and provide various program graphs of schools and communities for happiness and satisfaction in life. This study verified that the participation of leisure activities of adolescents has a significant effect on school life satisfaction, and that happiness and life satisfaction have a mediating effect on school life satisfaction. In addition, we could recognize the importance of leisure activities to the satisfaction of school life of teenagers, and find it necessary to develop and provide various program graphs of schools and communities for happiness and satisfaction in life. Therefore, this research is believed to be possible to contribute to academic and practical programs for youth leisure activities and school life relationships, and to make policy suggestions for the development and participation of various leisure activities in order to fully enjoy and protect youth's rights to culture and self-determination of leisure activities.

• Composites Research
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• v.17 no.3
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• pp.1-7
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• 2004

In the vacuum assisted RTM (VARTM) process that has become the center of attention for manufacturing massive composite structures, a good evacuation of air in the fiber preform is recognized as the prime factor. The microvoids, or the dry spots, are formed as a result of improper gate/vent locations and the mold geometry. The non-uniform resin velocity at the flow front leads to the formation of microvoids in the fibers, whereas the air in the microvoids can migrate along with the resin flow during mold filling. The residual air in the internal voids of a composite structure may cause a degradation of the mechanical properties as well as the structural failure. In this study, a unified macro- and micro analysis methods were developed to investigate the formation and transport of air in resin during VARTM process. A numerical simulation program was developed to analyze the three-dimensional flow pattern as well as the macro- and microscopic distribution of air in a composite part fabricated by VARTM process.

• Journal of Digital Convergence
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• v.17 no.3
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• pp.361-369
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• 2019

The purpose of this study was to investigate the adaptation factor to North Korean refugees by identifying the relationship between character strengths affecting adaptation process and psychological well-being(PWB) in South Korea. The study examined the relationship between PWB and character strength of 117 participants and identified the sub-factors of character strength that affect the settlement period in South Korea. The data were analyzed by using the Model 1 of Process Macro and SPSS 22. The results of this study showed a correlation between PWB and sub-factors of character strength such as wisdom, humanity, courage, justice, temperance, and spirituality. The main effect was to investigate the relationship between PWB and sub-factors of character strength by independent variables. The level of PWB increased with the level of sub-factors of character strength. The moderate effect was showed in the courage of the settling period in relation to PWB. Finally, Limitations and implications of this study was discussed.