• Journal of the Korean Society of Industry Convergence
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• v.21 no.3
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• pp.141-147
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• 2018

In a time when product development cycles are getting shorter and shorter, many companies are making efforts to develop products with high reliability in a short period of time, accelerated life test is widely used as a method to quickly evaluate reliability. Accelerated life test reduces the test life or the life of the product from the observed data by shortening the lifetime of the product or abruptly lowering the performance under the worse condition than the actual condition in order to shorten the test cost or the test time. In this paper, BL3640A-06P+RB35, DC12V model, which is used in the support device of an automatic rotation type digital signage, which display various information such as textures and images on a display screen in a public place or a commercial space, BLDC motors were subjected to a constant stress test and at the rotational speed of 1rpm, $180^{\circ}$ rotation and reverse rotation under actual use conditions, the stress was imposed on the rotating speed of 2rpm and the weight of the actual installed product from 22.2kgf to 10kgf were installed. The lifetime of the actual use environment condition is 23,545 hours and the rotation speed is accelerated. The life time of the acceleration condition with the additional weight is 1,380 hours. The acceleration factor is calculated as 17.06, the one year guarantee test day is 235 days to 14 days, of the period from 470 days to 28 days, and the third year from 704 days to 42 days. The test date of the BLDC motor was tested on the shortened test date, and the rotational speed and the current value were measured. It is found that there is no defect even if it operates as the test date corresponding to the specified one year warranty period and the 3 year accelerated life test which is experimented. Using the statistical technique of the regression analysis the expected time for the motor to defect to #4 samples was 20 years.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.352-360
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• 2018

The purpose of this study was to examine the level of human rights sensitivity and the types of perception in regards to the human rights of college students to enhance their human rights sensitivity. The study methodology included a t-test and variance analysis for the level of human rights sensitivity, and a Q-factor analysis for the perception types of human rights. As a result of examining whether there is a difference in human right sensitivity, it was found that female students were higher than male students, and juniors and seniors were higher than freshmen and sophomores. The human rights sensitivity of the students in the social and science department were the highest, and those who had volunteer experiences were more susceptible to human rights than those who did not. Students who registered for organ donation were higher than those who did not, and those who received human rights education showed higher human rights susceptibility than those who did not. Four perception types of human rights were analyzed 'universal social moralists', those who have an idealistic mindset and make decisions based on moral standards, 'practical realists', those who have no intention of breaking out of the social norm and who do not want to take any risks for human rights, 'social system advocates', those who have a clear understanding of the basic human rights concept, but don't think that they should break the rules of society for the sake of individual rights, and 'social contracts advocates', those who are willing to bend the rules of society for human rights, but not to the extent of ruining relationships. These study results are expected to contribute to the possibility of the social viewpoint that human rights sensitivity can be developed in the context of social experience as well as perception.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.183-193
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• 2018

The purpose of this study was to assess the implications for Daejeon's business management by analyzing the impact on the management performance of human solidarity among CEOs of small and medium venture companies in Daejeon. From 20th March to 20th May 2018, 212 questionnaires were collected from CEOs of small and medium-sized venture companies in Daejeon for this study and verified using the SPSS statistics Analysis Program. As a result, the study confirmed that the "work" and "school" connection factors have positive effects on securing government projects, improving business management, acquiring the necessary information for business growth, and securing competitiveness in 4th industrial revolution era. On the other hand, the "Region or Kin-group" connection factor does not affect the management performance. The following implications were derived fromthese studies on sustainable growth and development of business in Daejeon. First, it requires a higher level of the CEO solidarity. Second, efforts aimed at building mutual trust among CEOs in Daejeon are needed to develop close relationships and strong connections. Third, each operating association established in Daejeon needs to develop various programs for building relationships among CEOs and operate programs to increase the chances of contact.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.388-395
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• 2020

This study was conducted from March 15 to March 19, 2019. The purpose of this study was to examine the recognition of uniforms and their images for the selection and development of uniforms and the pursuit of images for dental hygienists and students in some regions. Study methods included frequency analysis, factor analysis, reliability analysis, ANOVA, chi-squared test, and regression analysis. The collected data was analyzed using the IBM SPSS Statistics 21.0 program. This study found that students majoring in dental hygiene thought that uniforms influenced their image and that they influenced the image of the hospital. In addition, students who experienced clinical practice preferred the pants type to the uniform type and the color to achromatic color. In addition, these students preferred scrubs and the use of Crocs for shoes. The results of this study showed that dental hygiene students considered image transmission through uniforms as important. However, it appears that they prefer practical uniforms and shoes over uniforms that convey external images. This is a part that makes us aware of the need for changes in training clothes and training. In conclusion, it is necessary to develop a practical uniform while expressing the image of the institution, which will be reflected in future dental uniform selection.

• The Journal of the Korea Contents Association
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• v.12 no.3
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• pp.373-381
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• 2012

Due to IT(information technology) development, various ITs have been applied to tourism. Since June 2010, PDA guide service was launched in Kyungbok palace. This study tried to find how effectively the service is operated by comparing flow, satisfaction and reuse intention of PDA users with those of who have received guide service by professional interpreter. The result indicates that those who have received professional interpretation showed to be more involved, satisfied and have more intention to reuse. The paper explored the composing factors of PDA guide service, which are 'interpretation', 'design', 'ease of use', and 'stability of operation'. Among these factors, interpretation was analyzed to be only factor what affects users' involvement and also most influential attribute explaining users' satisfaction and reuse intention. 'Interpretation', 'stability' and 'ease of use' are shown to have impact on satisfaction, while 'interpretation' and 'stability' have significant effect on users' reuse intention of PDA guide service. The operational implications from these results are suggested.

• The Journal of the Korea Contents Association
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• v.14 no.8
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• pp.257-265
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• 2014

The purpose of this study was to examine the relationship of the self-rated peridontal health status of dental patients and the type of their treatment(implant, orthodontic treatment and general treatment) to the quality of life(happiness index), to investigate influential factors for oral health, and ultimately to provide some information on the development of oral health care programs geared toward boosting the happiness index. The subjects in this study were the patients who visited dental hospitals and clinics in Busan and South Gyeongsang Province. As for relationship between the field of treatment and the happiness index, the patients who received orthodontic treatment scored higher in both each itemand all the five items, and the patients who received implant treatment scored lower. Regarding links between self-rated periodontal health status and the happiness index, the patients who had no oral symptoms scored higher in both each item and all the five items, and the respondents whose self-rated health status and self-rated oral health status were both very good scored higher in the happiness index. The preparation of oral health programs that aim to improve the self-rated oral health of patients who visit dental hospitals or clinics is required.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.3
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• pp.357-373
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• 2013

In this paper, a back analysis program for analyzing the behavior of tunnel-ground system and evaluating the material properties and tunnel design parameters was developed. This program was designed to be able to implement the back analysis of underground structure by combination of using FLAC and optimized algorithm as direct method. In particular, Rosenbrock method which is able to do direct search without obtaining differential coefficient was adopted for the back analysis algorithm among optimization methods. This back analysis program was applied to the site to evaluate the design parameters. The back analysis was carried out using field measurement results from 5 sites. In the course of back analysis, nonlinear regression analysis was carried out to identify the optimum function of the measured ground displacement. Exponential function and fractional function were used for the regression analysis and total displacement calculated by optimum function was used as the back analysis input data. As a result, displacement recalculated through the back analysis using measured displacement of the structure showed 4.5% of error factor comparing to the measured data. Hence, the program developed in this study proved to be effectively applicable to tunnel analysis.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.5
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• pp.378-385
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• 2014

The chlorophyll-a concentration in algae bloom warning system of Hangang basin did not predict the cyanobacteria dominance. In this study, suggest the predicting indicator of cyanobacteria dominance through analyzing the environmental factors affecting on the cell count of cyanobacteria. Firstly, the dominance of algae was analyzed with seasonal variation during Jan. 2012~Sep. 2013. The diatom dominated phytoplankton communities during the period of January~April. In the May~June, the green algae dominated. And, the dominance of algae was changed to cyanobacteria in the July~August. Also, the environmental factors affecting to cyanobacteria blooms ; nutrients (TN, TP), temperature, precipitation, dam-discharge were evaluated during the study period. Rather than temperature factor, relatively low dam discharge causes cyanobacteria to grow rapidly and create a blooms. The low dam-discharge may increase the water retention time. Finally, it is proved that a low ratio of TN to TP (<29:1) can favour the development of cyanobacteria blooms. Thus, the predicting indicator (TN:TP) have need to apply to the alarm bloom warning system of Hangang basin.

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.2
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• pp.117-122
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• 2019

The objective of this study was to establish an in vitro culture system for ovarian preantral follicles of B6D2F1. First, we optimized the in vitro preantral-follicle culture by culture duration, follicle stimulating hormone (FSH) type, and activin A concentration. Duration of in vitro culture for 9, 11, and 13 days was sufficient for the normal development of preantral follicles to antral follicles. Formation of cumulus cell-oocyte complex (COC) was induced by treatment with human chorionic gonadotropin (hCG; 2.5 IU/mL) and epidermal growth factor (EGF; 5 ng/mL). In addition, metaphase II (MII) oocytes formed during this in vitro culture of preantral follicles. In vitro preantralfollicle culture for 9 days showed higher rates of growth and maturation, thus yielding a greater number of antral follicles, and there were significant differences (p < 0.05) in the number of MII oocytes (that formed from these preantral follicles via differentiation) between the 9-day culture and 11-day or 13-day culture. The follicles cultured for 9 days contained a tightly packed well-defined COC, whereas in follicles cultured for 11 days, the COC was not well defined (spreading was observed in the culture dish); the follicles cultured for 13 days disintegrated and released the oocyte. Second, we compared the growth of the preantral follicles in vitro in the presence of various FSH types. There were no significant differences in the growth and maturation rates and in differentiation into MII oocytes during in vitro culture between preantral follicles supplemented with FSH from Merck and those supplemented with FSH from Sigma. To increase the efficiency of MII oocyte formation, the preantral follicles were cultured at different activin A concentrations (0 to 200 ng/mL). The control follicles, which were not treated with activin A, showed the highest rate of differentiation into antral follicles and into MII oocytes among all the groups (0 to 200 ng/mL). Therefore, activin A (50 to 200 ng/mL) had a negative effect on oocyte maturation. Thus, in this study, we propose an in vitro system of preantral-follicle culture that can serve as a therapeutic strategy for fertility preservation of human oocytes for assisted reproductive medicine, for conservation of endangered species, and for creation of superior breeds.

• Analytical Science and Technology
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• v.26 no.2
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• pp.125-134
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• 2013

This study was demonstrated to estimate the measurement uncertainty of 23 multiple-component amino acids from beef bone extract by high performance liquid chromatography (HPLC). The sources of measurement uncertainty (i.e. sample weight, final volume, standard weight, purity, standard solution, calibration curve, recovery and repeatability) in associated with the analysis of amino acids were evaluated. The estimation of uncertainty obtained on the GUM (Guide to the expression of uncertainty in measurement) and EURACHEM document with mathematical calculation and statistical analysis. The content of total amino acids from beef bone extract was 36.18 g/100 g and the expanded uncertainty by multiplying coverage factor (k, 2.05~2.36) was 3.81 g/100 g at a 95% confidence level. The major contributors to the measurement uncertainty were identified in the order of recovery and repeatability (25.2%), sample pretreatment (24.5%), calibration-curve (24.0%) and weight of the reference material (10.4%). Therefore, more careful experiments are required in these steps to reduce uncertainties of amino acids analysis with a better personal proficiency improvement.