• Proceedings of the KIPE Conference
• /
• 2008.06a
• /
• pp.193-195
• /
• 2008

This paper proposed dc-dc converter with continuous output current for battery charger. If we charge energy storage device by conventional boost converter, current flows into the discontinuous and as a result reduces the life-time of battery. The output voltage of dc-dc converter should be higher than voltage of across the battery, specially if charging by PV there is a fluctuation of voltage due change of insolation and temperature, therefore will boost and regulate this voltage. The proposal converter includes forward converter and the output voltage of the proposal converter looks like an input voltage and forward output voltage's add. This topology was tested on simulation and experimentation. Simulation and experimentation results indicated that the proposal topology is useful for battery charging because the output current of the converter flows continuously and perfectly.

• The Journal of Korean Academic Society of Nursing Education
• /
• v.13 no.1
• /
• pp.13-22
• /
• 2007

Purpose: The purpose of this study was to determine learning styles and preferred learning methods of undergraduate nursing students in Korea. Method: Data was collected from 724 nursing students at five universities in Seoul, Busan, Daegu, Daejeon, and Gwangju. Kolb's Learning Style Inventory, a self-report questionnaire was completed. Result: Learning styles of nursing students were diverger 43.5%, accommodator 36.7%, assimilator 10.8%, or converger 9.0% Learning styles were significantly different related to preferred future clinical practice area and grade. Furthermore, active experimentation(AE) learning mode was significantly different by grade. Concrete experience(CE), conceptualization(AC), and active experimentation(AE) learning modes were significantly different preferred future clinical practice area. preferred learning methods were lecture 40.7%, clinical practice 37.2%, self-directed learning 8.7%, laboratory practice 8.0%, and group discussion 5.4%. Preferred learning methods were significantly different by learning styles and grade. Lecture was preferred in diverger and assimilator. Clinical practice was preferred in accommodator and converger. Styles Conclusion: This study suggested that nursing education should be applied to nursing students after examining learning styles and preferred learning methods. In conclusion, nursing educators should help to develop various learning modes for student's balanced learning capabilities.

• Journal of Korea Water Resources Association
• /
• v.36 no.2
• /
• pp.237-249
• /
• 2003

Wind effects on a rain gauge can cause a significant underestimation of rainfall depths and contribute to the inconsistency in rainfall data. To revise the rainfall data requires the study about calculation of deficiency percentages of rain catch. There are few studies which reflect the variation of wind speed. in this study, the raindrop terminal velocity is quantified according to the particle size of rainfall. The model for calculating deficiency percentages of rain catch according to the particle size of rainfall is examined by experimentation. Experimentation shows that deficiency percentages of rain catch have no relationship with rainfall intensity and affected by raindrop diameter. In conclusion, the estimated deficiency percentages of rain catch coincided with the experimental results and can be used as recommended adjustment factors.

• Journal of the Korea Society for Simulation
• /
• v.30 no.1
• /
• pp.21-29
• /
• 2021

This paper introduces experimental design and components model for analysing the impact of parameter(in the field of kinematics and sensor) on performance of hard-kill torpedo defence system. The simulation is implemented at the level of engagement and its scope is limited to final stage of engagement where main function of anti-torpedo system is operating. It improves the fidelity of physical realism by precise model of simulation components in the perspectives of kinematics, sensor capability and acoustic detection theory. This paper provides the experimentation methodology for evaluating parameter sensitivity which is required to analyze in advance of development the defense system with novel concepts. In addition, the experimental result shows the tendency of defense capability according to parameter adjustments.

• Journal of Korean Society for Quality Management
• /
• v.49 no.1
• /
• pp.31-45
• /
• 2021

Purpose: A noncentral composite design method is to be developed to explore farther region for the first factorial design. A general guideline for sequential experimentation is provided. Methods: (1) A non-overlapping noncentral composite design (NNCD) is developed, in which the second factorial design shares one design point that indicates the best response value in the first factorial design. (2) Four composite designs are compared in terms of the four design evaluation criteria, which are D-, A, G, and I-optimality. (3) A follow-up design strategy is suggested based on the interaction effect, direction of improvement, number of factors. Results: (1) NNCD and model building method are presented, which is useful for exploring farther region from first factorial design block. (2) The performances of the four composite designs are compared. (3) A follow-up design strategy is suggested. Conclusion: (1) NNCD will be useful to explore farther region for the first factorial design. (2) A follow-up design strategy can be beneficial to the experimental practitioners for product and process design and improvement.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.48 no.3
• /
• pp.397-416
• /
• 2024

This study investigated gender characteristics in contemporary virtual fashion design, focusing on avatars and genderless fashion in recent collections from Auroboros, Republiqe, Placebo Digital Fashion House, RTFKT, and Tribute. Employing content analysis within a theoretical framework of gender-related research, the study coded virtual avatars in terms of biological sex, appearance, and sociological perspectives. The results showed a preference for female-type avatars, through which androgynous aesthetics were embraced and traditional gender norms were challenged. Male-type avatars reflected experimentation with blending masculine elements, emphasizing inclusivity. Human-like avatars indicated a preference for designs that promoted inclusivity and, in the process, challenged binary classifications. The examined brands strategically capitalized on compromise, sensuality, and playfulness, thereby breaking away from traditional values to opt for more diverse styles. Genderless features combined elements from traditional men's and women's clothing, espousing sensuality and playful exaggeration. These findings signify a dynamic shift away from conventional gender standards to foster inclusivity and experimentation. They can serve as a reference for promoting creative strategies and design innovation, challenging the traditional gender perspective in the fashion industry. Implementing these strategies can lead to a more inclusive representation of fashion styles, encouraging critical thinking about gender norms.

• Journal of Periodontal and Implant Science
• /
• v.47 no.5
• /
• pp.339-350
• /
• 2017

Purpose: The purpose of this study was to determine the critical diabetes duration in a streptozotocin (STZ)-induced diabetic rat calvarial defect model for experimentation regarding bone regeneration by evaluating the association between diabetes duration and bone healing capacity through histological and radiographic analyses. Methods: Experimental diabetes was induced in 50 of 60 rats by an STZ injection. The rats were divided into 5 groups, including a control group (group 1), according to diabetes durations of 0, 2, 4, 6, and 8 weeks, respectively. Eighteen rats survived: 4 in group 1, 4 in group 2, 4 in group 3, 5 in group 4, and 1 in group 5. Calvarial defects were created at 0, 2, 4, 6, and 8 weeks after STZ injection in groups 1-5. Cone-beam computed tomography scanning was performed at baseline and at 5 and 7 weeks after surgery. The rats were sacrificed 7 weeks after surgery, followed by histological evaluation. Results: The voxel gray values (VGVs) of group 1 and group 2 increased, whereas the VGVs of group 3 and group 4 decreased starting 5 weeks after surgery, although this trend did not reach statistical significance between groups. On the reconstructed 3-dimensional images and based on an analysis of histological features, groups 1 and 2 showed apparent bone regeneration, while groups 3-5 showed very limited bone regeneration. Conclusions: The critical diabetes duration in an STZ-induced diabetic rat calvarial defect model for experimentation regarding bone regeneration was between 2 and 4 weeks. It is suggested that researchers who use STZ-induced diabetic rats wait for more than 2 weeks following diabetes induction before placing implants or conducting bone regeneration studies to allow definite disturbances in bone healing to emerge.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.33 no.7
• /
• pp.1154-1161
• /
• 2004

The objective of this study was to evaluate microbiological Quality of HACCP application in elementary school foodservice operations. Microbiological Quality of utensils and non-heated foods such as salad was measured two times at five elementary schools in Daegu. The two experimentations differed in that after the first experimentation employees were educated and trained on HACCP based sanitation standards with a goal of improving microbiological Quality of foodservice. Microbiological Quality, time, and temperature were evaluated at three critical control points (CCPs)： washing and disinfecting, personal hygiene and non-cross contamination. Micro-biological Quality was assessed using 3M petrifilm to measure total plate count and coliform group. The first experimentation showed low microbiological Quality due to cross contamination of utensils and cooking gloves; high microbiological count of the garlic, powdered red pepper, and ginger; and not thoroughly washing and disinfecting vegetables. In the second experimentation, microbiological Quality was greatly improved by washing and thoroughly disinfecting raw ingredients and utensils, and using good personal hygiene. However, microbiological Quality of seasonings was still low. Immediate corrective actions were required in one of the foodservice operations that was assessed. These results strongly suggest that foodservice operations should address non-heated food Quality. It is essential to measure microbiological Quality regularly and continually train and retrain employees on hand washing and disinfecting raw ingredients. Further studies are needed to determine whether pathogens are present in raw vegetables and seasonings.

• Journal of Environmental Science International
• /
• v.13 no.3
• /
• pp.301-311
• /
• 2004

The purpose of this study was to examine teachers’ awareness of chemical waste produced in elementary school laboratory experimentation and how this awareness relates to collection and disposal of chemical waste. More specifically, the study looked at the correlation between the handling of chemical waste and factors such as years of teachers’ educational career, class size and amount of waste produced. The target population were 250 elementary school teachers in Gyeongnam area and 237 subjects were responded. Among the 237 responses, 37 cases that did not complete the questionnaire were eliminated. Therefore, 200 responses were analyzed in this study. The survey questionnaire consisted of 15 questions. The categories of the questionnaire were their skills of management and treatment of the chemical waste. The data collected were analyzed by SPSS 10.0, and the relations among variables such as class sizes and years of teaching experience were also analyzed by $x^2-test.$ The results in this study were as follows: First, there were no significant differences between the years of teaching and class sizes in the training experience of chemical waste disposal. Second, there was a significant difference between the science laboratory size and class sizes in the laboratory actual condition. In addition, in the relations between the number of times of experimentation and the years of teaching experience, there was a significant difference. Third, in terms of the discharge amount of chemical waste, there was a significant difference between the years of teaching and class sizes. Fourth, in the simple chemistry waste disposal process in the science laboratory, there also was a significant difference between the kinds of experimental equipments that used in the experimentation and the years of teaching. Based on this study, it was found that great amount of the chemical wastes produced in the science laboratory dumped into the drain and the treatment process of chemical waste was also inattentive. Even the importance of environmental education is emphasized in the elementary education, the basic problems occurred in the science laboratory is disregarded. Therefore, not only students but teachers have to pay attention to the disposal process of chemical waste in the laboratory in order to prevent environment pollution. Furthermore, the efforts of preventing environment pollution are needed such as opening the teacher training course about environment education, minimal use of chemicals, treatment of chemical waste, and so forth.

• Environmental and Resource Economics Review
• /
• v.27 no.3
• /
• pp.421-461
• /
• 2018

Windpower turbines have positive values for visitors with regard to tourism and learning. On the other hand, it is clear that windpower turbines have negative impact on the landscape, particularly when the level of landscape is high. The impact of windpower turbines on the visitor's value is composed of two elements: the viewingvalue which is independent of the level of landscape and the landscape value which varies with the level of landscape. The net visitor's value of windpower turbines is the sum of these two values with opposite signs. This study used a choice experimentation method to value the impact of windpower turbine construction in the mountainous area in Korea. This study estimated the viewing value, the landscape value and the visit value as the sum of the two values. The estimated results demonstrated a significantly positive viewing value, a significantly negative landscape value, and weakly negative net visit value in average.