• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.04a
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• pp.7-10
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• 2002

We designed the flyback planar transformer, which had 8W capacity, with 70V input voltage and 8.2V output voltage for the establishment of design method and the confirmation of application possibility. The numerical value of inductance measured under the switching frequency of 120 kHz was 1650 ${\mu}H$, which was the inductance efficiency of 85~87% against theoretical value. The A.C. resistance of primary and secondary coil was 4.2 ${\Omega}$ and 0.25 ${\Omega}$ respectively. On the other hand, the quality factor for each wound numbers showed quite a high value of 158 and 75 respectively. And the Coupling Factor was 0.96~0.97 under 120 kHz switching frequency. And the shape of the output wave of the planar transformer at 70V input voltage was a stable square wave.

• Journal of Electrical Engineering and Technology
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• v.3 no.2
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• pp.243-253
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• 2008

This paper deals with the analysis, design, and implementation of a single phase AC-DC Zeta converter with high frequency transformer isolation and power factor correction(PFC) in two modes of operation, discontinuous current mode of operation(DCM), and continuous current mode of operation(CCM). A Digital Signal Processor(DSP) based implementation is carried out for validation of the Zeta converter developed design in discontinuous mode of operation. A comparison of both modes of operation is presented for a 1kW power rating from the point of view of steady state and dynamic behavior, power quality, simplicity, control technique, device rating, and converter size. The experimental results of a developed prototype of Zeta converter are presented for validation of the developed design. It is observed that CCM is most suitable for higher power applications where it requires some complex control and sensing of the additional variables.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.11
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• pp.641-649
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• 2017

In the study, the water quality of the Imjin River basin with pollutants of changing characteristics it was determined through statistical analysis, correlation analysis, principle component and factor analysis, and cluster analysis. Among all analyzed data points, the average water quality concentration at the Sincheon 3 site shows high levels of BOD 13.4 mg/L, COD 19.9 mg/L, T-N 11.145 mg/L, T-P 0.336 mg/L, TOC 14.2 mg/L, indicating that Sincheon basin requires intersive water quality management out of the entire drainage basin. The correlational analysis of comprehensive water quality data shows statistically significant correlation between COD, TOC, BOD, T-N water quality factors, as well as finding of high correlation between organic and nutrients. The principal component analysis show that 2 main components being extracted at 81.221% from the measuring station's entire data, while seasonal data show 3 main components being extracted at 96.241%. Factor analysis of the entire data set and the seasonal data identify BOD, COD, T-N, T-P, TOC as the common factors influencing water quality. The spatial and temporal cluster analysis showed 4 groups and 3 groups, respectively, according to seasonal characteristics and land use. By analysing the water quality factors for the Imjin River basins over an 8 year period, with consideration to the spatial and temporal characteristics, this study will become the fundamental analytic data that will help understand the future changes of water quality in the Imjin River basin.

• Journal of the Korea Fashion and Costume Design Association
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• v.11 no.3
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• pp.153-162
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• 2009

The purpose of this study was to examine the differences in the service quality evaluation on the skill and expert, the shop facilities and atmosphere, the time and access, and the price and benefit of a nail care shop by age, income, spendings of appearance and a nail care, and a regular nail care. The survey was performed with questionnaires and the subjects were was 240 consumers who used the nail care. The data were analyzed by frequencies, F-test, T-test, Factor Analysis, one way ANOVA. The results of the study were as follows: Service quality evaluation were classified four factors- the price and benefits, the skill and expertness, the facilities and atmosphere, the time and access. There were no statistically significant differences in the price and benefits by age, income, spendings of appearance and a nail care, and a regular nail care, but there were statistically significant differences in the skill and expertness, the facilities and atmosphere, and the time and access. The service quality on the time and access was evaluated as high by the consumer in the 30s, with more income, and with high appearance and nail care spendings. The service quality on the shop facilities and atmosphere was evaluated as high by the consumers with high nail care spending. The consumers with a regular nail care evaluated the service quality on the skill and expertness, the time and access, the shop facilities and atmosphere as high.

• Analytical Science and Technology
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• v.19 no.6
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• pp.544-552
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• 2006

Emission tests were carried out to investigate the characteristics of concentration according to flooring sort using small chamber method. The target Volatile Organic Compounds (VOC) included 27 individual compounds of environmental concern, which were determined by adsorption sampling and thermal desorption coupled with GC/MS method and by DNPH cartridge/HPLC method. The emission factor of Total Volatile Organic Compounds (TVOC) and Formaldehyde (HCHO) was detected $0.3mg/m^2{\cdot}h$ and $0.2mg/m^2{\cdot}h$ respectively, and the floorings of 37 (9 PVC Tile, 10 PVC Sheet, 18 Flooring) were satisfied emission standard. TVOC emission factor appeared in order of concentration of PVC Sheet, PVC Tile, and floor flooring, while HCHO was detected very high emission factor (as $0.4mg/m^2{\cdot}h$) at floor flooring above PVC series (as $0.001mg/m^2{\cdot}h$).

• Journal of the Korean Society of Food Culture
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• v.1 no.2
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• pp.142-156
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• 1986

The purpose of the present study was to investigate the value evaluation of food in urban Korean adolescents. The conclusions drawn from the analysis of values of foods are as follows: 1. There are five factors drawn from the analysis of values of foods, that is, subjective evaluational factor. Objective factors are social factor, economic factor, quality attribute factor, and freguency of food intake factor. And it has been revealed that there is some relationship between these factors. The subjective evaluational variable depends most strongly on the sensory variable, especially taste, flavor, color and shape of food, described in the order of influence. It also depends on the experiential frequency of intake. 2. With regard to the attitude of evaluation of food, there is a considerable difference between junior high school students and high school students, and between male and female students, This difference can be noticed in almost all the variables dealt with in this study, especially in the subjective evaluational aspect, experiential aspect, and social aspect, A significant difference was found between junior high school students and high school students and between male and female students on both subjective and objective values of foods. Male students valued food which brought about a 'Satiety' more so than female. And consequently, they take such kinds of foods more frequently. More female students than male students and more junior high school students than high school students have a strong conception of the socio-cultural value of foods, that is, the spatial and temporal symbol of foods.

• The Korean Journal of Community Living Science
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• v.20 no.3
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• pp.397-411
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• 2009

The use of local product foods and fresh-cut products, the dietitian's recognition, the required items and the quality for school foodservice was investigated to increase the consumption of high-quality agricultural products. Data from 578 elementary schools, 228 middle schools and 116 high schools were collected by school foodservice personnels in each regional Education Administration in Gyeong-gi province. The first criteria of buying food materials was reliability/safety for all school foodservice. The second criteria were the origin of the product and freshness/ripeness for elementary and middle schools and high school, respectively. The most important consideration for selecting a supplier was the quality of the material. The appearance/status of the food was the first factor for buying food materials. The origin and the seasonality were very important for buying farm products. Dietitians in Gyeong-gi province recognized the local products, and used them weekly. The advantages of using local products were the quick supply, freshness and safety. On the other hand, the disadvantages were the lack of information and the uncertainty of supply. Sixty eight percent of the subjects had experienced the high-quality agricultural products in school meals, but the frequency was low. The main reasons for not servicing high-quality agricultural products were the high cost and the lack of trust on the quality. Among fresh-cut products, seasonings and root vegetables were purchased most frequently, but leaf vegetables was 5.7% only. The purchase of fresh-cut products was not frequent, but usually satisfied. The advantages of fresh-cut products were the reduced workload and waste, but the reason for not using them were poor hygiene and the high price. The diverse supply system and the promotion of the local product foods would be necessary since the most food materials were purchased through suppliers. In addition, the problems related to the high cost and distrust should be resolved to expand the consumption of the high-quality agricultural products and the fresh-cut vegetables. The institutions for certifying the quality should be needed to increase the confidence of these products.

• The Journal of the Korea Contents Association
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• v.10 no.1
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• pp.426-435
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• 2010

The object of this study was to develop an index of service quality of waterparks and verify the validity and reliability of the index. This study represents the waterparks user population in 2009, and 250 people were extracted by using the purposive sampling method. In other words, five locations have major waterparks were chosen and 50 people per each location were collected. Conference, panel survey, exploratory factor analysis and confirmatory factor analysis were performed to verify the validity of the questionnaire while item analysis, interrater reliability and internal consistency reliability were conducted to probate the reliability. Through these methods and procedures, the results of this study like these; (i) Validity of this index was significantly high and the index include amenity/cleanness, safety, price, programs, facilities, accessibility and promotion. Among them, amenity/cleanness was the major factor for the validity value; (ii) Reliability of this index was also high. There are high correlations between questions and fields and questions and total score. And the Cronbach's $\alpha$ values of the internal consistency reliability was over 0.603 except in the case of promotion which was below 0.6. After all the analysis, the index of service quality proved to be very proper and reliable index. Therefore, the major factors of service quality have to be figured out and reflected to the management innovation to improve service quality of waterparks.

• Journal of Korean Academy of Nursing
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• v.38 no.3
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• pp.474-482
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• 2008

Purpose: The purposes of this study were; 1) to test the validity and reliability of the Korean version of Rantz's Observable Indicators of Nursing Home Care Quality Instrument (ONHQ) and 2) to evaluate the quality of Korean nursing homes. Methods: The study employed a three-phase methodological research design. 1) The original instrument of Rantz's. ONHQ was translated into Korean and modified by Korean nursing home experts. 2) A pilot study using the modified instrument was done in 20 nursing homes to examine inter-rater reliability. 3) The validity and reliability were tested.in 98 nursing homes. Results: Seven factors were extracted through factor analysis: 'communication', 'care delivery', 'grooming', 'odor, 'environment-basics', 'environment-access', and 'environment-homelike'. These factors explained 86.07% of the total variance. Cronbach's alpha coefficient of the 30 items was .97 indicating a high internal consistency of the instrument. Inter-rater reliability according to Kappa was .82. The average score of nursing home quality was 112.07 indicating an average range of quality level. Conclusion: The Korean version of the ONHQ was identified as a tool with a high degree of validity and reliability. This tool can be effectively used to assess the quality of nursing homes by professions as well as family members.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.3
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• pp.155-160
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• 2000

The piezoelectric properties and the doping effect for$0.95Pb(Zr_xTi_{1-x})O_3+0.05Pb(Mn1/3Nb2/3)O_3$ compositions were studied. Also, the heat generation and the change of electromechanical characteristics, the important problem in practical usage, were investigated under high electric field driving. As a experiment results under low electric field, the values of kp and $\varepsilon33T$ were maximized, but Qm was minimized(Kp=0.57, Qm=1550) in the composition of x=0.51. In order to increase the values of Qm $Nb_2O_5$ was used as a dopant. As the result of that, the grain size was suppressed and the uniformity of grain was improved. Also, the values of kp decreased, and the values of Qm increased with doping concentration of $Nb_2O_5$. As a experiment results under high electric field driving, when vibration velocity was lower than 0.6[m/s], the temperature increase was $20[^{\circ}C]$, and the change ratio of mechanical quality factor was less than 10[%]. So, its electromechanical characteristics was very stable. Conclusively, piezoelectric ceramic composition investigated at this paper is suitable for application to high power piezoelectric devices.