• Journal of the Korean Dietetic Association
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• v.11 no.3
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• pp.320-330
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• 2005

The purpose of the study was to assess students’preferences on vegetarian menus served at middle and high schools. Four school food service programs that served primarily vegetarian menus were located in Seoul, Kyunggi, Kangwon, and Choongnam provinces. A total of 100 menu items frequently served at the schools were identified. Students participating in the school meals programs were asked to assess their preferences of the menus using a 5-point Likert-type scale(1 : very dislike - 5 : very like). Excluding responses with significant missing data, usable responses were 659. Statistical analyses were performed with descriptive statistics, t-tests, and one-way analysis of variance. Menu items of the highest preference scores included kimchi stew, stir-fried kimchi, nangmyon(cold noodles), fried rice and kimchi, miso stew, soft tofu stew, and hard-boiled quail eggs in soy sauce. By menu category, one-dish foods(3.97) were the most preferred and muchim and namul were the least preferred. Female students showed higher preferences on kimchi, steamed items(jjim), stir-fried items, namul, and muchim than male students; middle school students’preference scores were higher than those of the high school students in most menu categories. The menu preference is known as one of the most important factors determining students’food consumption and satisfaction with school food service. Dietitians working at school food service programs that serve primarily vegetarian menus should provide students with nutrition education on proper food selection and focus their efforts on developing new recipes using various vegetables and preparation methods to improve students’food consumption and menu preference.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.219-228
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• 2019

Thanks to the development of information technology and the vitalization of smart services, the Internet of Things (IoT) technology, in which various smart devices are connected to the network, has been continuously developed. In the legacy IoT architecture, data processing has been centralized based on cloud computing, but there are concerns about a single point of failure, end-to-end transmission delay, and security. To solve these problems, it is necessary to apply decentralized blockchain technology to the IoT. However, it is hard for the IoT devices with limited computing power to mine blocks, which consumes a great amount of computing resources. To overcome this difficulty, this paper proposes an IoT architecture based on the edge computing technology that can apply blockchain technology to IoT devices, which lack computing resources. This paper also presents an operaional procedure of blockchain in the edge computing-based IoT architecture.

• Solar Energy
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• v.11 no.3
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• pp.44-52
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• 1991

The benefits of thermal stratification in sensible heat storage systems has been considered and studying by several investigators. In this paper, the basic data which is hard to obtain normally through the experiment were obtainable through the computer simulation. The major objectives of the study were to assess the benefits of stratified storage in residential solar water heating application and to suggest the optimum design parameters. From the computer simulation, following results were obtained. 1. The solar load fraction increases with increasing the number of tank segments. In these simulation, the magnitude of the improvement was about 10%. 2. The solar load fraction increases when the ratio of diameter to height of the tank(H/D) increases to 3, but H/D exceed 3 then, the solar load fraction decreases. In these simulation, the magnitude of the improvement was about 3%. 3. Increasing the collector flow rate slightly improved the performance of the mixed storage system(Node=1). But, for the stratified storage system(Node=N), the solar load fraction increases with decreasing flow rate until the point is reached at which the collector outlet temperature reaches the boiloff limit of $100^{\circ}C$ over some portion of the simulation period.

• Journal of the Korea Fashion and Costume Design Association
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• v.10 no.2
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• pp.79-89
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• 2008

The purpose of this study is to evaluate the differences among visual images under variations in shoulder length and puff volume of the puff sleeve blouse. The stimuli are 21 samples: three variations of shoulder length and seven variations of puff volume. The data has been obtained from 40 fashion design majors, where they had been analyzed through frequency, factor analysis, ANOVA, Scheffe's test and MCA method. The results of the study are as the following: As a result, through factor analysis of the visual images according to the variation of shoulder point and puff volume, the following four factors had been identified. Factor 1 is the brightness from evaluation terms such as childish-precocious, cute-mature, bright-genteel, soft-hard, enlarged-reduced, particular-ordinary, interesting- uninteresting, etc. Factor 2 is the attractiveness from evaluation terms such as refine-rustic, stylish-dull, attractive-unattractive, modern-classic, urban-rural, cool-gloomy, spacious-tight. etc. Factor 3 is the comfortness from evaluation terms such as comfort-discomfort, intense-indistinct, etc. Factor 4 is the elegance from evaluation terms such as elegance-shallowness, womanish-manly, etc. These four factors were 66.7% of the total variables. Of the total variables, the first factor had been evaluated as brightness in 26.2%, attractive in 21.0%, comfortness in 11.1%, and elegance in 8.4%. From this study, the more puff volume and shorter shoulder length, the puff volume wrapped the shoulder naturally, thus making the shoulder look narrow, and giving a cute and bright image. However, by having less puff volume and excessively short shoulder length, the puff volume did not naturally wrap the shoulder, which gave an unnatural and unattractive feel.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.122-124
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• 2003

In recent, the various electric & electronic machines are newly developed everyday and the electricity supply system & environment on the process from generation to consumption of electricity also is being changed. In other words, both supplier and consumer of electricity are required to be responsible for their interruption costs. So, it is very important and meaningful work for evaluating the interruption costs in quantitative. Additionally, since the restructuring of electric industry is on going in world wide, after restructuring, most of all electric utilities and consumer have to consider the supply reliability and quality as a important element of the calculating the related costs and contract because it takes costs to keep the supply reliability and quality highly. Especially, the interruption or the supply reliability will have influence on the bilateral contract between supplier and customer as a key point to determine the once in competitive electric market. Therefore, it has very important moaning to calculate the interruption costs in the present that it is prepared to open the competitive electric market. In this paper, international standards, i.e. IEC, IEEE, are applied to the analysis on the interruption costs used in the questionnaires which are newly designed including short duration interruption by the authors instead of traditional interruption criteria. Firstly, using the questionnaires, the authors got related data from industries according to the standard industry classification which are being used in electric utility and other national statistics in Korea. However, analysis results are hard to say typical value because of the not so many samples. So, the authors are going to survey and focus on not all kinds of industry but a few kinds of them that their facilities are effected or stop by short duration interruptions, so there are large economical damages. Finally, the authors hope to find the reliable and meaningful model in interruption costs of industrial customer.

• The Journal of Advanced Prosthodontics
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• v.14 no.5
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• pp.305-314
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• 2022

PURPOSE. The aim of this study was to evaluate the flexural strength of a 3D-printed denture base resin (Cosmos Denture), after different immediate repair techniques with surface treatments and thermocycling. MATERIALS AND METHODS. Rectangular 3D-printed denture base resin (Cosmos Denture) specimens (N = 130) were thermocycled (5,000 cycles, 5℃ and 55℃) before and after the different repair techniques (n = 10 per group) using an autopolymerized acrylic resin (Jet, J) or a hard relining resin (Soft Confort, SC), and different surface treatments: Jet resin monomer for 180 s (MMA), blasting with aluminum oxide (JAT) or erbium: yttrium-aluminum-garnet laser (L). The control group were intact specimens. A three-point flexural strength test was performed, and data (MPa) were analyzed by ANOVA and Games-Howell post hoc test (α = 0.05). Each failure was observed and classified through stereomicroscope images and the surface treatments were viewed by scanning electron microscope (SEM). RESULTS. Control group showed the highest mean of flexural strength, statistically different from the other groups (P < .001), followed by MMA+J group. The groups with L treatment were statistically similar to the MMA groups (P > .05). The JAT+J group was better than the SC and JAT+SC groups (P < .05), but similar to the other groups (P > .05). Adhesive failures were most observed in JAT groups, especially when repaired with SC. The SEM images showed surface changes for all treatments, except JAT alone. CONCLUSION. Denture bases fabricated with 3D-printed resin should be preferably repaired with MMA+J. SC and JAT+SC showed the worst results. Blasting impaired the adhesion of the SC resin.

• Journal of The Korean Association For Science Education
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• v.17 no.1
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• pp.55-64
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• 1997

Experiments done in traditional physics laboratories have been criticized for giving too detailed instruction so that student could follow the experimental procedure without understanding. This type of experiment is often called "cookbook experiment." Cookbook experiment was known to be little help to understand the physics concepts and to increase student interest. To solve these problems with traditional cookbook experiment, non-directive introductory physics laboratory was designed and tried with the freshmen of Department of Physics Education of Seoul National University. Non-directive laboratory was characterized by the lack of step by step instruction for students to follow. The instruction students received consisted of the goal of experiment, a short introduction, and a list of suggested materials to be used. Student designed the experimental procedure and decided what material they wanted to use. One group submitted one lab report as a group to encourage cooperation among students. Lab report could be written in any form students wanted and no penalty point was given to poor data or inappropriate theory, etc to encourage taking risks. Penalty points were given if the students did not get involved during class hours. Student received extra point for being creative and / or working hard. Teaching assistants used Socratic dialogue in helping students to find their own way instead of explaining what they had to do. Students' interest about the non-directive experiment was studies at the of the semester. A questionnaire was made for students to answer. The questionnaire consisted of four categories, the equipment and the laboratory, the experimental procedure, the lab report, and teaching assistant. For each category, student were asked to explain the differences from other laboratory classes, features they liked and the reasons why they do, features they did not like and why they did not. At the end of the questionnaire, students were asked what hey wanted to change and what they did not. They also could put any opinion they had other than the questions asked. Student overall opinion was very positive. All the students said they liked the lack of detailed experimental procedure because it gave them the feeling of achievement, made them feel challenged and think in more diverse and creative ways. Students liked the lab report because group report forced them to discuss more and the free form lab report helped them to focus on the what they did. Student responses about the teaching assistant was also positive but not as enthusiastic as the experimental procedure or lab report. However students recognised that the role of the teaching assistant was as a guide, a supporter, or a facilitator.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.168-176
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• 2017

This is a descriptive study to determine the influence of character strength of nursing students on perceived stress. Data were collected from 174 nursing students in the A- area and analyzed using SPSS WIN 21.0 program. The character strength of nursing studentswas $3.46{\pm}.34$(on a 5-point scale) and perceived stress was $2.84{\pm}.42$(on a 5-point scale). Among the subdomains of character strengths, humanity was the highest,with a score of $3.65{\pm}.49$. The perceived stress of nursing students showed a negative correlation with character strength(r=-.50, p<.001) and was negatively correlated with all subdomains of character strength. In addition, the factor that most affected the perceived stress of nursing students-among general characteristics-was very difficult family experience (${\beta}=.146$, p=.026), and the factors with the greatest effect among the subdomains of character strengths were courage(${\beta}=-.250$, p=.006) and transcendence(${\beta}=-.275$, p=.013). These three factors were found to explain 39.5% of variance in perceived stress. Therefore, these results demonstrate the need to explore interventions that enable nursing school faculty and counseling staff to help confirm character strengths and reduce stress in students with hard time getting adjusted to nursing school.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.3
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• pp.209-218
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• 2011

The present study proposes a new estimation relationship for the transmission rate of the steel breakwater which is expected to make up for the weakness points in existing hard solution for shore protection. The steel breakwater consists of the wave dissipator of the dual horizontal plates, the supporting columns and their foundations, and thus its respective designs should also be conducted one by one. Furthermore, the breakwater has to ensure both functions of shore protection and structure stabilization. The study produced experimental data for the stability and safety investigation of the steel breakwater. The forces acting on the steel breakwater were classified into two categories, one is vertical up and down loads for the pile resistance and the other was maximum difference of the vertical load acting on horizontally different position for the torsion. The study applied the stability force produced by the summation of maximum pressure at each point and the safety force acting on each point simultaneously. The regular wave corresponding to the significant wave was utilized for measuring wave pressure and force. The study showed the method for the proper position of submerged upper plate by considering occurrence frequency of tide level. The design process finally determined by trial and error is proposed in the present study.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.2
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• pp.47-55
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• 2010

The power line communication channel has characteristic variation problems which are caused by load. The spread spectrum technique has been used to overcome these problems. One of that is the direct sequence spread spectrum(DS/SS) system which is not necessary to additional hardwares. The BER of DS/SS system is decreased by longer length of PN code, but data transfer rate is decreases, so data transfer rate is hard to satisfies their own specifications especially in narrowband PLC systems. Spread Spectrum system with Dual-processing Gain tries to reflect cyclic characteristics of power line noise. But that system assumes that shapes of power line channel are symmetrical with respect to the 1/4 point of main frequency(60Hz in Korea), therefore cannot achieves various shapes of real power line noise. Thus in this paper, noise adaptive DS/SS system which PN code is changed by noise levels for various channel noises is proposed and simulated. The different kinds of noises are modeled and measured for simulation, the proposed system is verified that has lower data transfer rate and lower error rate than conventional system by simulation results.