• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.7
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• pp.417-427
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• 2016

This paper is the first investigation of the steady flow characteristics of an SI engine with a semi-wedge combustion chamber as a function of the port shape. For this purpose, the planar velocity profiles were measured at the 1.75B position by particle image velocimetry. The flow patterns were examined with both a straight and a helical port. Two swirls were observed up to 4 mm valve lift with the straight port and up to 2 mm with the helical one; however, only one swirl was present after these lifts. The flow characteristics changed suddenly between 4 and 5 mm lift in the straight port; on the other hand, the change with lift was gradual with the helical port - the transition points between flow regimes were different with the port shapes. In addition, the centers of the swirls were relatively far from the cylinder center so that the effect of eccentricity may not be negligible at 1.75B, regardless the shape. The eccentricity values with the straight port were especially high - over 0.5 for all lifts. Finally, real velocities were found to be much lower than those predicted by the assumption of ISM evaluation, with the profiles differing qualitatively as well.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.3
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• pp.301-307
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• 2010

Actuation using a shape memory alloy (SMA) is considered to be an important technology that will play a leading role in market for next-generation medical devices because an SMA actuator can accurately imitate skillful and delicate hand movements. However, SMA actuators have not been successfully used because of problems in control design caused by the nonlinear hysteresis effect of SMA, which leads to inaccuracies in control systems. In order to overcome the effect, the authors invented a SMA actuator, which could actively and rapidly cool down and heat up, by combining a SMA catheter and a TE module using the Peltier effect. In order to evaluate the TE characteristics of our TE module system, the changes in the temperature with 1) incremental increases in a continuous electric current and 2) the appearance of a discontinuous constant or reverse current are discussed in this paper.

• Journal of the Korea Society of Computer and Information
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• v.18 no.10
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• pp.245-252
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• 2013

The purpose of this study is to propose the implications after investigating how gifted education affected the school achievements and academic skills of students who have experience of gifted education. In this study, academic skills include academic knowledge, creative problem solving skills, logical thinking, persuasive skills, collaborative skills, self-directed learning skills, communication skills. The survey was conducted with 1,156 science high school and science academy students who have ongoing gifted education experience and depth interviews were also analyzed with some students to gather further in-depth information. As a result, students responded that gifted education affected very positively on knowledge, collaborative skills, communication skills and increased interest in related subjects. On the other hand, it showed lower positive responses on self-directed learning skills and persuasive skills. Also, students replied gifted education did not affect the school achievements but there was an opportunity to learn how to debate, research, and experiment and practice methods. The direction of gifted education to step forward was suggested based on these results. This study can be the basis for revising gifted education curriculum.

• The Journal of Natural Sciences
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• v.10 no.1
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• pp.199-208
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• 1998

This study forecasts the trend of ethnic theme through market survey, concentrating on Los Angeles market. First, the background of ethnic theme was examined, and the present situation of shops, department sores, and headquarter was also surveyed. After that, fashion trend suitable for market was suggested by analyzing the life style of consumers through zip code. The results of the study are as follows. The conspicuous trend of '97 F/W retail stores is ethnic. This reaction to complicated modern life, and symbolizes the desirable evaluation on the simpleness of basic life and nature. The model of ethnic design is identified in natural clothing, primitive arts, ethnic culture and African theme. In short, this ethnic fashion is expressed as simpleness, naturalism convenience and freedom. On the other hand, the standard of general department stores such as Broadway and Robinson May which are the headquarter of this trend is to satisfy various consumers with various styles. Ethnic goods from Broadway has not arrived at the top for its introducing step. To elevate sales of these goods, promotion through VMD and suggesting various ethnic goods should be done. Besides, when analyzing the consumers of Beverly center Broadway, the target of these goods are mostly professional young people in their 25-34 and 35-44. The life style of these people emphasizes sophisticated life in aspects such as job-oriented activities, and up-to-date fashion. Especially, image is very important. They want individuality different from others. These images are diversified from simpleness, naiveness to sexy character. Accordingly, suggesting fashion trend satisfying the demand of consumers through market survey will make fashion market create infinite possibilities.

• Journal of the Korean Society for Railway
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• v.18 no.2
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• pp.139-148
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• 2015

By increasing the vertical stiffness of the rail fastening system, the dynamic wheel load of the vehicle can be increased on the ballast track, though this increases the cost of track maintenance. On the other hand, the resistance acting on the wheel is decreased, which lowers the cost of the electric power to run the train. For this reason, the determination of the optimal fastener stiffness is important when attempting to minimize the economic costs associated with both track maintenance and energy to operate the train. In this study, a numerical method for evaluating the optimal vertical stiffness of the fasteners used on ballast track is presented on the basis of the process proposed by L$\acute{o}$pez-Pita et al. They used an approximation formula while calculating the dynamic wheel load. The evaluated fastener stiffness is mainly affected by the calculated dynamic wheel load. In this study, the dynamic wheel load is more precisely evaluated with an advanced vehicle-track interaction model. An appropriate range of the stiffness of the fastener applicable to the design of ballast track along domestic high-speed lines is proposed.

• Food Science and Preservation
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• v.18 no.4
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• pp.502-507
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• 2011

To investigate the optimal salting conditions, the physicochemical properties of Dolsan leaf mustard were compared under various salting times and using various washing methods and storage temperatures at 10% saline. On the other hand, the cell number of lactic-acid bacteria in Dolsan leaf mustard salted under the optimal conditions was also examined during the 50-day storage. The results of the sensory evaluation of the crispness value of the Dolsan leaf mustard treated with stepwise washing after 8h salting showed the optimal conditions for long-term preservation. The pH of the salted Dolsan leaf mustard decreased with the increase in the lactic-acid bacteria during the storage at $4^{\circ}C$. The cutting energy slowly increased during the storage, but the cutting energy of the salted Dolsan leaf mustard treated with stepwise washing remained at the initial values. The color of the salted Dolsan leaf mustard did not change during 40-day storage, but the mustard turned brown after 50-day storage, for which reason it could not be made into Dolsan leaf mustard kimchi. These results could be recommended as the optimal salting conditions and storage time of salted Dolsan leaf mustard for making kimchi.

• Journal of Oral Medicine and Pain
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• v.30 no.1
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• pp.121-129
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• 2005

In this experiment, eleven volunteers were followed up for 15 months after the injection of botulinum toxin type A on right and left masseter muscles. The measurement of masseter muscle atrophy for each volunteer was performed by CT(computed tomography) three times: before the injection, three and fifteen months after the injection. The thickness and area of muscle were measured in three positions which are 10 (position 1), 20 (position 2), and 40 mm (position 3) above the inferior border of mandible(the injection site was nearest the position 1). The thickness of masster muscle was decreased in all three positions three months after the injection, but no significant change was observed fifteen months after the injection. On the other hand, the area of masster muscle was decreased in all three positions three months after the injection. Furthermore, the area was decreased significantly in positions 1 and 2, but not in position 3 fifteen months after the injection. As a result, toxin is still in effect even fifteen months after the injection. Finally, the present study shows that the measurement of muscle area provides more precise informations than that of muscle thickness does.

• Korean Journal of Community Nutrition
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• v.24 no.6
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• pp.497-511
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• 2019

Objectives: This study aimed to develop a school-centered healthy eating environment for children in elementary care classrooms and prevent incorrect eating habits and obesity through the development and application of standardized healthy eating habit-forming educational materials. Methods: Ten schools in eight districts of Gyeonggi-do and 400 students from 19 care classes were selected. Based on the developed educational materials, the program was applied to students once in two weeks. 'Notices for Parents' forms were also sent to the students' home to educate their parents. Pre and post-surveys were conducted to evaluate the effectiveness of the education. The pre-education, education, and aftercare were conducted from September 28 to September 31, 2016, from October 3 to November 30, 2016, and from December 5 to December 9, 2016, respectively. Results: The healthy eating program for elementary care classes was designed to develop a school-centered healthy eating environment and provide standardized educational material for healthy eating habits. Twelve educational topics were developed: , , , , , , , , , , , and . Moreover, the materials were produced in four forms: for students, for after school caring teachers, for external specialists, and for parents. The effectiveness evaluation was conducted to confirm the application of the program. The average eating habits score was 3.3 ± 0.6, with no significant difference between before and after application. The score of overall satisfaction of the education was 3.9 ± 0.9. The most satisfying content was 'Did you get to know how to eat evenly?'. Significant increases were observed in two contents for parents regarding their children's knowledge changes after the education: 'Five nutrients needed for growing children' and 'Knowing sugar foods and sugar-containing foods'. On the other hand, their educational satisfaction was 3.6 ± 0.6, which was lower than the children's satisfaction. This might be because their education was conducted only through the 'Notices for Parents' form. Conclusions: In the long term, the healthy eating habit-formation education for lower elementary school children is expected to be beneficial. To prevent obesity and establish healthy eating habits of children, it is important to develop healthy eating education programs centered on elementary school aftercare classes, including the development of educational materials and an application system through connection with the home and community.

• Korean Journal of Agricultural Science
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• v.29 no.1
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• pp.66-83
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• 2002

The economic feasibility analysis including benefit-cost ratio and internal rate of return of a land consolidation and on-farm development project was mainly depended upon the direct benefits and costs arising during project life. Therefore the projects were neglected in allocating the government's financial funds and loans on account of the low economic rate of return of the project. Accordingly the extended benefit-cost analysis method should be introduced and adapted to cover not only the benefit s such as non-market values of environmental and food security fun ct ions of the project but also market values of the project outputs. The main purposes of this study are (1) to prepare a guide line for economic feasibility analysis based on the IBRD and ADB guidelines, (2) to estimate the benefits from productivity increase, labor saving, savings of O&M cost of farm mechanization and project facilities, savings of farmer's burden for their public health, increasing environmental and public functional value of paddy fields, improving food security condition and formation of peaceful and uncontroversial rural society by implementing the land consolidation and on-farm development, (3) to introduce the newly adapted analytical method as the extended benefit cost analysis which could make possible to be included the values of non-market goods such as the food security and the environmental public function of paddy fields. To carry out this study, the existing publications on the guidelines for economic agricultural projects were reviewed and consultation was made with a For the post evaluation study of the land consolidation and on-farm development project, field survey in Jigok and other comparative area were made to get available information. According to the project completion report, Jigok land consolidation and on-farm development project has 55ha of benefit area out of 69ha of gross area. The project was started in November 11th, 2000 and completed october 30th, 2001. The total project costs were amounted to 2,548 million won and the annual project benefits were estimated at 335million won evaluated by domestic market prices. The ERR(Economic Rate of Return) and SRR(Social Rate of Return) of the project based on the shadow pricing system were estimated at 4.4% and 16% respectively. On the other hand, the ERR and SRR based on the domestic market value system were amounted to 6.37% and 14.62%. In conclusion, Korean land consolidation and on-farm development projects have not carried out from the view point of economic rate of return under shadow pricing system but from the view point of domestic pricing system. For the future feasibility studies on land consolidation projects have to be carried out including the non-market values as environmental and food security function of the projects.

• Clinical and Experimental Reproductive Medicine
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• v.4 no.2
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• pp.23-34
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• 1977

A study was carried out for the evaluation on family situation of 900 homemakers those who had received tubal sterilization operation (laparoscopic and minilaparotomy) at family planning clinic, Seoul Red Cross Hospital from October 1974 to September 1977. The results obtained are as follows: 1) In age distribution, predominant age group consisted of those $31{\sim}35$ years frequency of 43.2% and average age was 33.3 years. 2) Educational level showed that homemakers who finished primary school accounted for 37.3% of the total and those having middle school education comprised 28.7%, and 24.3% of them were high school graduates, 8.3% of them were college graduates. On the other hand, husband's education level showed that, 37.6% of them were high school graduates, 29.7% were college graduates and 19.9% were middle school graduates, therefor, educational level of husbands was one step higher than wives. 3) In the gravidity at the tubal sterilization, the highest incidence(18.4%) among 853cases was the group of gravida 5, and 16.2% gravida 4, and the gravidity ranged $1{\sim}23$. Average gravidity of clients was 6.0. 4) Among the total number of 900 clients, 778cases (91.3%) had no experience of spontanous abortion, history of 1 abortion in 5.9%, 2 abortions in 1.8%, and it showed the decresed incidence of spontanous abortion recently. Average was 0.15. As regarding induced abortion, in spite of only 142 homemakers (16.7%) had no history of induced abortion, 20.5% had experienced 1 induced abortion before sterilization, 17.7% had 2 induced abortions, 14.6% had 3 abortions, 10.3% had 4 abortions, and 0.2% (2cases) had over 20 abortions. Average was 2.7. 5) In regarding to the number of living children, the greatest number (45.0%) of clients had 3 children, and 26.5% 2 children, 19.7% 4 children. Average number of their living children was 3.03. 6) Sex ratio of living children, among 18 clients those had 1 child, 17 homemakers had 1 boy and no girl, 1 homemaker had no boy and 1 girl only. Sex ratio showed that woman who had 2 boys and no girl accounted for 46.3%, however, those having no boy and 2 girls ocmprised only 1. 8% among 229 clients who had 2 children. Among 389 clients who had 3 children, in spite of woman who had 3 boys and no girl comprised 16.5%, but no boy and 3 girls only 1.5%. Among 170 clients who had 4 children, homemakers with 4 boys and no girl accounted for 4.1%, however, no boy and 4 girls 1.8% of the total. Among 52 clients, who had 5 children, woman with 5 boys and no girl comprised 3.9%, no boy and 5 girls 0%. Among 7 cases who had 6 children, there were 3 cases who had 3 boys and 3 girls, but only 1 cases had 1 boy and 5 girls and so on. These results showed a strong trend of male preference in Korea and this could be one of the inhibit factors for family planning.