• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.11
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• pp.763-770
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• 2022

In an environment where multiple drones are operated, collisions can occur when path points overlap, and collision avoidance in preparation for this is essential. When multiple drones perform multiple tasks, it is not appropriate to use a method to generate a collision-avoiding path in the path planning phase because the path of the drone is complex and there are too many collision prediction points. In this paper, we generate a path through a commonly used path generation algorithm and propose a collision avoidance method using speed profile optimization from that path segment. The safe distance between drones was considered at the expected point of collision between paths of drones, and it was designed to assign a speed profile to the path segment. The optimization problem was defined by setting the distance between drones as variables in the flight time equation. We constructed the constraints through linearize and convexification, and compared the computation time of SQP and convex optimization method in multiple drone operating environments. Finally, we confirmed whether the results of performing convex optimization in the 20 drone operating environments were suitable for the multiple drone operating system proposed in this study.

• Journal of the Korean Society of Food Culture
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• v.38 no.6
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• pp.402-414
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• 2023

This study evaluated the consumers' demands and points of improvement for restaurant meal replacement through importance-performance analysis by the restaurant meal replacement segment market using food involvement. The results were as follows. First, after segmenting the restaurant meal replacement market using food involvement, it was classified into three markets (multiple involvements, exploration-oriented, and product quality-oriented). Second, an analysis of the importance of restaurant meal replacement selection attributes revealed taste, sanitation, quality, freshness, price, saving time, texture, ingredients, preparation process, and quantity to be highly important. An analysis of the differences according to the market type revealed the multiple involvement type to be more important than other groups, considering the restaurant meal replacement selection attribute element. Third, an analysis of the importance-performance analysis of restaurant meal replacement selection attributes revealed that quantity and price as the selection attributes that needed to be improved first in all three markets. In addition, in the multiple involvement type, food additives appeared as a selection attribute requiring priority improvement, revealing the characteristics of a market that cares about diet and health.

• Fisheries and Aquatic Sciences
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• v.10 no.3
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• pp.103-112
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• 2007

High prices, overfishing, and contamination have limited the availability of natural caviar as a food product. We attempted to apply encapsulation by calcium-alginate gel membranes to caviar analog preparation in an effort to produce a high-quality replacement for natural caviar. Physical conditions of stirring speed $(X_1,\;rpm)$ and gelation time $(X_2,\;min)$ as the independent variables for gelation were optimized by response surface methodology. Sphericity $(Y_1,\;%)$, diameter $(Y_2,\;mm)$, membrane thickness $(Y_3,\;mm)$, rupture strength $(Y_4,\;g)$, and rupturing deformation $(Y_5,\;mm)$ were used as the dependent variables to compare characteristics of the capsules for caviar analogs with natural caviar. The values of the independent variables as evaluated by multiple response optimization were $X_1=-0.1271 (278 rpm) and $X_2=0.4436$ (12.2 min), respectively. Predicted values of the four dependent variables were $Y_1=97.7%,\;Y_2=2.97mm,\;Y_4=1,465g,\;and\;Y_5=1.15mm$. Membrane thickness $(Y_3)$ was eliminated from the dependent variables for multiple response optimization because it could not be measured with an image analyzer. The experimental values prepared under the optimal conditions for verification nearly coincided with the predicted values and satisfied the conditions of natural caviar.

• Journal of Families and Better Life
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• v.26 no.5
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• pp.355-376
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• 2008

The purpose of this study was to investigate the variables that had an effect on the maturity of career attitude in middle school students. Independent variables were categorized into three groups: individual-related variables, family-related variables, and school-related variables. The individual-related variables were gender difference, academic year, academic achievement, and self-efficacy. The family-related variables were socio-economic status of the family, communication about career with parents, parental support, sibling's support, and value orientation of the family. The school-related variables included communication about career with friends, teacher's support, and friend's support. The subjects of this study were 490 students who were selected at random from first, second, and third grade of middle school in Daegu. A questionnaire was used for the survey. It consisted of a career attitude maturity scale, a self-efficacy scale, a communication scale, a value orientation of the family scale, and a social support scale. The data was analyzed by factor analysis, multiple regression analysis, and hierarchical regression analysis. The major findings of this study are summarized as follow: First, among the individual-related variables that had an effect on the maturity of career attitude in middle school students, self-efficacy affected all sub-factors of how mature they were in matters relating to career. Academic achievement affected decisiveness and preparation-- maturity of career attitude subfactors. And gender difference and academic year affected preparation and goal orientation. Second, the results of the family-related variables that had an effect on the maturity of career attitudes in middle school students were that communication about career with parents affected decisiveness, preparation, and confidence-- maturity of career attitude sub-factors, socio-economic status of the family and sibling's support affected confidence. And value orientation of the family affected goal orientation and independence. Third, the results of the school-related variables that had an effect on the maturity of career attitude in middle school students were that communication about career with friends affected preparation-- a maturity of career attitude sub-factor; teacher's support affected decisiveness, preparation, and confidence; and friend's support affected confidence and independence. Fourth, decisiveness, preparation, and confidence among the maturity of career attitude sub-factors were affected the most by individual variables. And self-efficacy was the most significant. Goal orientation and independence were affected the most by family-related variables.

• Journal of Korea Entertainment Industry Association
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• v.14 no.7
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• pp.549-558
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• 2020

The purpose of this study is to provide basic data for the establishment of welfare facilities for baby boomers and the development of services and programs by studying the effects of baby boomers' preparation for old age on the intention to use welfare facilities for the elderly. The subjects of this study were 385 baby boomers (1955-1963) living in J city, Chungbuk. Multiple regression analysis was conducted to examine the factors influencing the intention to enter welfare facilities. The results of this study showed that baby boomers' preparation for old age did not have a significant effect on the intention to use the elderly welfare center, and only the economic preparation had a significant effect on the intention to use the senior club, and the emotional preparation had a significant effect on the intention to use the 50+ center and the baby boomer welfare center. Based on the results of this study, policy suggestions are as follows: First, senior clubs need to expand services for employment and start-up that can help prepare for economic retirement. Second, various job policies using baby boomers' skills and knowledge are needed. Third, the 50+ center and the baby boomer welfare center need to develop professional counseling and education programs for prevention and treatment of emotional and psychological problems. Fourth, it is necessary to provide and develop programs to promote interpersonal relations and social activities for emotional stability and support.

• Journal of Industrial Convergence
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• v.21 no.12
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• pp.141-151
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• 2023

This study aimed to investigate the influence of learning flow, career decision-making self-efficacy, and major satisfaction on career preparation behaviors among nursing students. Data were collected by questionnaire from 15th September 2022 to 14th October 2022, from 208 nursing students at universities in provinces the G and J. And the data answered to the questionnaire were analyzed by descriptive analysis, t-test, One-way ANOVA, Pearson's correlation, and Stepwise Regression Analysis. As a result of this study, career preparation behaviors was analysed based on learning flow (r=.515, p<.001), career decision-making self-efficacy (r=.681, p<.001) and major satisfaction (r=.621, p<.001). The results of the multiple regression analysis showed that the influential factors on career preparation behaviour were career decision-making self-efficacy (𝛽=.446, p<.001), major satisfaction (𝛽=.285, p<.001), third grade (𝛽=.157, p=.001), learning flow (𝛽=.133, p=.018), and second grade (𝛽=.106, p=.038), and the explanatory power of the career preparation behavior was 57.0%. Therefore, there is a need to provide customised education through a career programme that takes into account the career path chosen by nursing students.

• Restorative Dentistry and Endodontics
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• v.23 no.2
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• pp.537-549
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• 1998

The purpose of this study was to evaluate the influence of root resection and retrograde cavity preparation methods on the apical leakage in endodontic surgery. To investigate the effect of various root resection and retrograde cavity preparation methods on the apical leakage, 71 roots of extracted human maxillary anterior teeth and 44 mesiobuccal roots of extracted human maxillary first molars were used. Root canals of the all the specimens were prepared with step-back technique and filled with gutta-percha by lateral condensation method. Three millimeters of each root was resected at a 45 degree angle or perpendicular to the long axis of the tooth according to the groups. Retrograde cavities were prepared with ultrasonic instruments or a slow-speed round bur, and occlusal access cavities were filled with zinc oxide eugenol cement. Three coats of clear nail polish were placed on the lateral and coronal surfaces of the specimens except the apical cut one millimeter. All the specimens were immerged in 2% methylene blue solution for 7 days in an incubator at $37^{\circ}C$. The teeth were dissolved in 14 ml of 35% nitric acid solution and the dye present within the root canal system was returned to solution. The leakage of dye was quantitatively measured via spectrophotometric method. The obtained data were analysed statistically using two-way ANOVA and Duncans Multiple Range Test. The results were as follows: 1. No statistically significant difference was observed between ultrasonic retrograde cavity preparation method and slow-speed round bur technique, without apical bevel (p>0.05). 2. Ultrasonic retrograde preparation method showed significantly less apical leakage than slow-speed round bur technique, with bevel (p<0.0001). 3. No statistically significant difference was found between beveled resected root surface and non-beveled resected root surface, with ultrasonic technique (p>0.05). 4. Non-beveled resected root surface showed significantly less apical leakage than beveled resected root surface, with slow-speed round bur technique (p<0.0001). 5. No statistically significant difference in apical leakage was found between the group of retrograde cavity prepared parallel to the long axis of the tooth and the group of one prepared perpendicular to the long axis of the tooth (p>0.05). 6. Regarding isthmus preparation, ultrasonic retrograde preparation method showed significantly less apical leakage than slow-speed round bur technique, in the mesiobuccal root of maxillary molar, without bevel (p<0.0001).

• Journal of Pharmaceutical Investigation
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• v.37 no.4
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• pp.217-222
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• 2007

To develop cleansing tissue composed of silicone multiple emulsions which could easily remove make-up residues and confer skin protecting effect without damaging skin, we formulated various silicone multiple emulsions and evaluated the physicochemical properties including viscosity, cleansing effect, and safety effect. Also, cleansing tissue incorporated with silicone multiple (W/Si/W) emulsion was stored for 6 months, and judged its stability through microscopes under accelerated and long-term condition. Cleansing effect was evaluated by chromameter. Skin hydration effect was determined by corneometer and incorporation effect into non-woven fabric cotton was evaluated by volunteer survey. Low viscosity ranged from 400 centipoise (cP) to 1,000 cP was obtained from a stabilized W/Si/W emulsion containing more than 10% volatile silicone. Mean diameter of fresh W/Si/W emulsion was $20{\mu}m$, but after storage for 3 months at $45^{\circ}C$, the particle size of the W/Si/W emulsion increased up to $50{\mu}m$. Both W/Si/W emulsion-incorporated cleansing tissue and commercial product showed equally good cleansing effect. In addition, skin allergies such as erythema, edema, scaling itching, stinging, burning, tightness and prickling were not observed through macroscopic examination. From the transepidermal water loss results, the cleansing tissue consisting of W/Si/W emulsion showed superior hydration effect to commercial product. In conclusion, this study suggests cleansing tissue using W/Si/W emulsion could be used for an excellent efficacy compared with commercialized cleansing tissue.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1229-1234
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• 2009

The rolling stocks of KORAIL are KTX, Saemaulho Multiple Unit(PP), New Electrical Locomotive(DL), Electrical Locomotive(EL), Diesel Locomotive, Metropolitan Commuter Train(CDC), VVVF and Resistance Controlled Multiple Unit, etc. EMU with the maximum speed of 150km/h is under the test run at the moment. Electrical Multiple Units for mainlines with 180km/h speed are supposed to be introduced as a substitute for Saemaulho Multiple Unit which is scheduled to be out of service. But the specification standard for the control board design of train driver's cab does not exist and there is no a study for layout and type of controlling device with driver's ergonomical approach. That's why the types of controller and operating are different from rolling stocks, which has high possibility of driver's human error and needs education whenever a new car comes in. Based on the opinion poll of drivers, design specification of safety engineering and ergonomics for controlling devices and safety facilities can improve exact control for devices and deal quickly with an emergency so as to improve rolling stock safety and operational efficiency.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.11 no.4
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• pp.229-237
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• 2011

As smart phones have become widely adopted, they have brought about changes in individual lifestyles, as well as significant changes in the industry. As the mobile technology of smart phones has become associated with all areas of industry, it is not only accelerating innovation in other industries such as shopping, healthcare service, education, and finance, but is also creating new markets and business opportunities. The preparation of thorough security measures for smart phones is increasing in demand. While offering excellent mobility and convenience, smart phones can be exposed to a range of violation threats. In particular, it is necessary to make efforts to develop a security system that can preemptively cope with potential security threats in the banking service area, which requires a high level of reliability. This paper suggests a security reference model that is considered for the smart phone-based joint mobile banking development project being undertaken by the Bank of Korea in 2010. The purpose of this study is to make a security reference model for a reliable smart phone-based mobile financial service, by recognizing the specific security threats directed toward smart phones, and providing countermeasures to these security threats. The proposed mobile banking security reference model is useful in improving system security by systematically analyzing information security threats to the mobile financial service, and by presenting the guideline for the preparation of countermeasures.