• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.2
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• pp.39-45
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• 2013

Basically, in order to apply solid propellant as ignition source to high energy metal particle combustion system, we analyzed combustion characteristics of the HTPB/AP/Al, HTPE/AP/Al propellants by using a strand burner. The propellants were tested in a high-pressure windowed strand burner, which was pressurized up to 300 psia with pure argon gas. Strand burner was visualized with two quartz windows and ignition was accomplished by a 10 W $CO_2$ laser. The burning rate of propellant was measured with high-speed camera method for frame analysis and photodiode method for combustion time analysis. Emission spectrum was measured with spectrometer at 300 nm ~ 800 nm and 1500 nm ~ 5000 nm and then we analyzed species during propellant combustion.

• Journal of the Korean Solar Energy Society
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• v.28 no.5
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• pp.14-20
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• 2008

As the number of buildings that use the transparent permeation materials as the outer wall is on the increase, the coming amount of the light rays is a lot, and thus the increase in the cooling load and the radiant heat of high temperature may cause the residents to discomfort. In order to reduce such influences, this paper analyzed the installation effects of the sunshade BIPV. The inner temperature of the room installed the sunshade BIPV or otherwise was measured, and compared and analyzed the effects of reducing the cooling load by the incoming light rays. The sample space of the third floor of S university installed the sunshade BIPV has two rooms on the same conditions, and for five sunny days selected in August, the researcher measured the air temperature and the temperature of the fittings with closing the windows to minimize the movement of air without operating the coolers. The maximum cooling load measured by the incoming light rays in the room where the sunshade BIPV was not installed was examined as 459.13kcal/h. It can be understood as the effect of reducing the cooling load according to the incoming rays of the room with sunshade BIPV. Even though the effect of cooling load reduction is not so great in a room, the total reduction in cooling room for the 32 rooms installed the sunshade BIPV was estimated to be 40442.27kcal/day, which will be able to bring the maximum reduction effect of 17.1kW in energy and reduce the investment cost owing to the reduction in cooling load when initially designing the building.

• Journal of Korean society of Dental Hygiene
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• v.19 no.5
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• pp.859-871
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• 2019

Objectives: The present study aimed to evaluate the usability, quality, and usefulness of the mobile application, CAMBRA-kids, for caries management in preschoolers. Methods: Ninety-one caregivers and preschoolers participated in the user evaluation of CAMBRA-kids. The evaluators assessed the usability, quality, and usefulness of CAMBRA-kids. The collected data were analyzed using R studio 1.2.1335 for Windows (RStudio Inc. 2018, Boston, MA, USA). The evaluations for usability, quality, and usefulness were analyzed with descriptive statistics, Kruskal-Wallis rank sum test, and Wilcoxon rank sum test. Results: On user evaluation, the quality and usefulness of the application scored >3 points, and majority of the users rated the quality and usefulness of the application as high. The quality of the application's system was the highest at 3.68 points, and the actual usage of the application was the lowest at 3.10 points. The application had the highest technological aspect score of 3.20, whereas the content related to oral health information had the lowest score of 3.10/5. Although the application showed no statistically significant differences in the quality and usefulness according to general characteristics, there was a statistically significant difference (p<0.05) between the two when compared between the caries risk group. For all items, the protector of the high-risk group evaluated the quality and usefulness of the application highly. The moderate risk group gave the lowest evaluation score for the application's quality and usefulness. The usability score of the application, according to the user version of the mobile application rating scale (uMARS), was 3.25, and the average engagement score was 2.82 (56.31%). The highest subscale score was 3.63. Conclusions: In this study, we found suitable quality, usability, and usefulness of the mobile application, CAMBRA-kids. In future, the use of this application will contribute to the prevention of dental caries among preschoolers.

• Convergence Security Journal
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• v.18 no.2
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• pp.33-40
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• 2018

ICT technology has been applied to various educational fields, but applying to educational test field is limited. Computer-based test (CBT) can overcome temporal and spatial constraints of conventional paper-based test, but is vulnerable to fraud by test parties. In this paper, we propose real-time monitoring and process management methods to enhance the security of CBT. In the proposed methods, the test screens of students are periodically captured and transferred to the professor screen to enable real-time monitoring, and the possible processes used for cheating can be blocked before testing. In order to monitor the screen of many students in real time, effective compression of the captured original image is important. We applied three-step compression methods: initial image compression, resolution reduction, and re-compression. Through this, the original image of about 6MB was converted into the storage image of about 3.8KB. We use the process extraction and management functions of Windows API to block the processes that may be used for cheating. The CBT system of this paper with the new security enhancement methods shows the superiority through comparison of the security related functions with the existing CBT systems.

• Journal of Korean society of Dental Hygiene
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• v.19 no.5
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• pp.813-824
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• 2019

Objectives: The purpose of this study was to investigate the effects of emotional labor, organizational climate, and job involvement on turnover intention in Korean dental hygienists. Methods: A total of 806 dental hygienists were enrolled in this study. A self-administered questionnaire was used to evaluate the demographic and occupational characteristics, emotional labor, organizational climate, job involvement, and turnover intention of the subjects. A hierarchical multiple regression analysis was performed. All statistical analyses were performed using the Statistical Package for the Social Sciences for Windows (version 23.0) and p-values < 0.05 were considered significant. Results: Highly chronic exposure to emotional labor were more likely to increase the risk of turnover intention among dental hygienists, especially in the sub-scales of "over-load and conflict in customer service" (OR: 1.64; CI: 1.01-2.64), "organizational surveillance and monitoring" (OR: 1.76; 95% CI: 1.21-2.57), and "lack of a supportive and protective system in the organization" (OR: 1.76; 95% CI: 1.36-2.46). Job involvement (OR: 0.91; 95% CI: 0.86-0.96) and organizational climate (OR: 0.82; 95% CI: 0.75-0.90) were negatively associated with turnover intention among dental hygienists. Conclusions: Exposure to chronic and excessive emotional labor might be a contributing factor for turnover intention, and job involvement and a positive organizational climate contribute to protecting the negative impacts of emotional labor on turnover intention in dental hygienists.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.4
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• pp.27-34
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• 2018

Flat or Multiple Dwelling Houses are relatively vulnerable to crime safety. Crime prevention measures are urgently needed because crime is 2.6 times higher than in real apartments. Through the analysis of domestic and foreign crime prevention design standards, field survey, and interviews with experts, 27 items of crime prevention design criteria for flat or multiple dwelling house were derived, and ten design criteria that should be considered first by the expert AHP were derived. As a result of the pilot evaluation of existing flat or multiple dwelling house, the houses completed after 2015 have relatively high level of crime prevention, but the houses constructed before that are very vulnerable. The policy and system improvement plan based on the analysis result is as follows. First, new housing should be promoted to meet minimum criteria by supplying and educating public officials, architects, and building owners in the short term to provide criteria for flat or multiple dwelling house crime prevention plans. Second, existing housing should be supported with basic crime prevention support projects such as security windows for flat or multiple dwelling house where security of residential environment such as urban renewal policy is poor. Third, the Enforcement Decree of the Building Act shall be revised to make the crime prevention environment design of flat or multiple dwelling house obligatory, and the criteria of flat or multiple dwelling house crime prevention plan should be reflected in the notice of crime prevention building standard.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.3
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• pp.341-348
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• 2020

The ability to extract useful information from an image, such as the human eye, is an interface technology essential for AI computer implementation. The building recognition technology has a lower recognition rate than other image recognition technologies due to the various building shapes, the ambient noise images according to the season, and the distortion by angle and distance. The computer vision based building recognition algorithms presented so far has limitations in discernment and expandability due to manual definition of building characteristics. This paper introduces the deep learning CNN (Convolutional Neural Network) model, and proposes new method to improve the recognition rate even by changes of building images caused by season, illumination, angle and perspective. This paper introduces the partial images that characterize the building, such as windows or wall images, and executes the training with whole building images. Experimental results show that the building recognition rate is improved by about 14% compared to the general CNN model.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.1
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• pp.113-119
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• 2004

Exponentiation is widely used in practical applications related with cryptography, and as the discrete log is easily solved in case of a low exponent n, a large exponent n is needed for a more secure system. However. since the time complexity for exponentiation algorithm increases in proportion to the n figure, the development of an exponentiation algorithm that can quickly process the results is becoming a crucial problem. In this paper, we propose a parallel exponentiation algorithm which can reduce the number of rounds with a fixed number of processors, where the field elements are in GF($2^m$), and also analyzed the round bound of the proposed algorithm. The proposed method uses window method which divides the exponent in a particular bit length and make idle processors in window value computation phase to multiply some terms of windows where the values are already computed. By this way. the proposed method has improved round bound.

• Journal of Creative Information Culture
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• v.5 no.3
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• pp.215-223
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• 2019

The wave of the information age gradually accelerates, and fusion analysis solutions that can utilize these knowledge data according to accumulation of various forms of big data such as large capacity texts, sounds, movies and the like are increasing, Reduction in the cost of storing data accordingly, development of social network service (SNS), etc. resulted in quantitative qualitative expansion of data. Such a situation makes possible utilization of data which was not trying to be existing, and the potential value and influence of the data are increasing. Research is being actively made to present future-oriented education systems by applying these fusion analysis systems to the improvement of the educational system. In this research, we conducted a big data analysis on Twitter, analyzed the natural language of the data and frequency analysis of the word, quantitative measure of how domestic windows education problems and outcomes were done in it as a solution.

• PNF and Movement
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• v.21 no.1
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• pp.129-137
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• 2023

Purpose: The physical therapy diagnosis process requires high-level background knowledge, the ability to obtain added information from patients, accurate examination skills, and a framework for transforming thoughts into a diagnostic decision. Thus, the physical therapy diagnostic process is highly complicated and difficult work. To function as autonomous professionals, physical therapists must develop effective clinical diagnosis skills. As such, mobile application aids can help with accurate and scientific diagnoses. Therefore, this study aims to develop and evaluate the usability of a mobile application for physical therapy diagnoses. Methods: In this study, a diagnostic application was developed using App Inventor, the development environment was the Chrome web browser for Windows 10, and the mobile application was run on a Google Pixel 5. The developed application was evaluated for usability by 20 physical therapists with more than 5 years of clinical experience in the musculoskeletal physical therapy field, and a usability evaluation was conducted using a 5-point Likert scale for accuracy, convenience, satisfaction, and usability. The collected Likert scores were converted into percentages and analyzed as descriptive statistics. Results: The graphical user interface consisted of an initial screen with program guidance, 18 screens presenting the algorithm, and 12 screens presenting the estimated diagnosis based on the algorithm. As such, the usability evaluation of the developed application was as follows: accuracy 100%, convenience 90%, satisfaction 91%, and usability 88%. Conclusion: The newly developed mobile application for physical therapeutic diagnoses has a high accuracy, and it will aid in building an easy and reliable physical therapy diagnosis system.