• Journal of Korean Dental Hygiene Science
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• v.6 no.2
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• pp.101-114
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• 2023

Background: This study aimed to explore the overall perception of pit and fissure sealants and suggest methods to revitalize their current stagnation. Methods: To determine the social perception of the change in coverage policy for pit and fissure sealants, we categorized them into five time periods. The first period (December 1, 2009 to November 30, 2010), the second period (December 1, 2010 to September 30, 2012), the third period (October 1, 2012 to May 5, 2013), the fourth period (May 6, 2013 to September 30, 2017), and the fifth period (October 1, 2017 to December 31, 2022). We utilized text mining, an unstructured big data analysis method. Keywords were collected and analyzed using Textom, and the frequency analysis of the top 30 keywords, structural features of the semantic network, centrality analysis, QAP correlation analysis, and co-occurrence analysis were conducted. Results: The frequency analysis showed that the top keywords for each time period were 'Cavities', 'Treatment', and 'Children'. In the structural features of the semantic network of pit and fissure sealants by time period, the density index was found to be around 1.00 for all time periods. The QAP correlation analysis showed the highest correlation between the first and second periods and the fourth and fifth periods with a correlation coefficient of 0.834. The co-occurrence analysis showed that 'cavities' and 'prevention were the top two words across all time periods. Conclusion: This study showed that pit and fissure sealants are well accepted by the society as a preventive treatment for caries. However, the awareness of health education related to these sealants was found to be low. Efforts to revitalize stagnant pit and fissure sealants need to be strengthened with effective education.

• Journal of Technologic Dentistry
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• v.41 no.4
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• pp.347-358
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• 2019

Purpose: The purpose of this study was to analyze dental technicians' job stress and Job satisfaction level and to examine its correlation. Methods: A self-administered survey was conducted from September 2 to October 2, 2019, on 230 selected dental technicians. The collected data were statistical data on frequency and percentage were obtained, and t-test, one-way ANOVA, correlation analysis and regression analysis were carried out. Results: When the job stress was analyzed, there were significant differences according to their field of work, working hours(p<.05). Their average score in the items about a job stress was 3.57. As a result of analyzing the job satisfaction of the dental technicians, there were significant differences according to their working hours, plan for task continuity in dental technician(p<.05). The average score in job satisfaction items was 3.11. Conclusion: As a result of research, that as for the correlation between a job stress and job satisfaction, a higher the job stress led to lower the job satisfaction, as every variable had a significant reverse correlation with each other. In addition, physical environment, heavy workload, conflict during the work performance, personal matters were identified as the factor that exerted the influence on both of job satisfaction.

• Journal of Sasang Constitutional Medicine
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• v.27 no.2
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• pp.288-296
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• 2015

Objectives Purpose of this study was to examine difference of taste score in herbal medicine among Sasang Constitution groups. Methods Seventy-three healthy students tasted salt solution, sucrose solution, four herbal medications (Hyangsayangwi-tang, Yanggyeoksanhwa-tang, Yeoldahanso-tang, and Mihudeungsikjang-tang), and then immediately scored intension of stimuli for each taste which they felt. Data of sixty-four final participant were analyzed by SPSS version 18, as follows: frequency analysis for characteristic data of participants, Kruskal-wallis test for difference in taste score among Sasang Constitution groups, and Pearson correlation analysis for the correlation between taste score of single taste stimuli and taste scores of herbal medications. Results Significant difference was shown in sweet taste score of Hyangsayangwi-tang among Sasang Constitution groups, that Soyangin showed higher sweet taste score of Hyangsayangwi-tang than Soeumin's. No significant difference was shown in other tastes or other herbal medications. Positive correlation between taste score of sucrose solution and sweet taste score of herbal medication was shown in Soemin. Conclusions There is difference in sweet taste score of Hyangsayangwi-tang among Sasang Constitution groups. There is positive correlation between sweet taste score of sucrose solution and herbal medication. This research has limitation, so well-designed research is needed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.1
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• pp.281-287
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• 2011

In anatomical education, cyber class has been studied as a strong strategy coincided with academic characterestics. In the present study, we investigated the correlation between self-evaluation factors, use of cyber classroom and academic achievement of health allied undergraduate students according to application of cyber class in the anatomical education. The subjects of study were totally 231 students who were majored in nursing science (n=143) and sports science (n=88) in last 3 years (2007-2009). Based on frequency of log-in, survey and grade of score, we analyzed correlation of their factors and their scores using frequency analysis, T-test and analysis of variance. Regardless of their major, most of students gave high scores in all of self-evaluation factors, convinience of cyber classroom, suitability of assignment. The frequency of log-in correlated highly with academic achievement(r=0.246, p<0.01, nursing science; r=0.234, p<0.05 sports medicine). The academic achievement also had a high correlation of 0.218(p<0.01) with the level of difficulty in nursing science students, 0.499(p<0.05) with the levels of satisfaction difficulty and interest. in sports science students. This study suggested that cyber class was very useful and would be a promising strategy in anatomical education.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.12
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• pp.1986-1991
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• 2016

The vibration soucre of motor has a electromagnetic and mechanical causes. The most widely known, electromagnetic reasons are cogging torque and RMF(Radial magnetic force). Recently, analysis of the cogging torque has been made actively. but analysis of the RMF was not filled. So, in this paper, analyzed RMF. the vibration test were performed for the basic and reduced model of cogging torque and RMF. And it analyzed for the effect of each factor on the vibration. Finally, the vibration was formulated for stator's weight and RMF. To this end, natural, cogging torque and RMF of frequency were analyzed and these relationships were considered.

• ETRI Journal
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• v.26 no.6
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• pp.622-634
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• 2004

In this paper, we discuss the design problem and the robustness of space-frequency trellis codes (SFTCs) for multiple input multiple output, orthogonal frequency division multiplexing (MIMO-OFDM) systems. We find that the channel constructed by the consecutive subcarriers of an OFDM block is a correlated fading channel with the regular correlation function of the number and time delay of the multipaths. By introducing the first-order auto-regressive model, we decompose the correlated fading channel into two independent components: a slow fading channel and a fast fading channel. Therefore, the design problem of SFTCs is converted into the joint design in both slow fading and fast fading channels. We present an improved design criterion for SFTCs. We also show that the SFTCs designed according to our criterion are robust against the multipath time delays. Simulation results are provided to confirm our theoretic analysis.

• Journal of Communications and Networks
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• v.8 no.1
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• pp.38-48
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• 2006

A synchronous multicarrier (MC) code-division multiple access (CDMA) system using inverse fast Fourier transform (IFFT) and fast Fourier transform (FFT) for the downlink mobile communication system operating in a frequency selective Rayleigh fading channel is analyzed. Both carrier frequency offset and timing offset are considered in the analysis. Bit error rate performance of the system with both equal gain combining and maximum ratio combining are obtained. The performance is compared to that of the conventional system using correlation receiver. It is shown that when subcarrier number is large, the system using IFFT/FFT has nearly the same performance as the conventional one, while when the sub carrier number is small, the system using IFFT/FFT will suffer slightly worse performance in the presence of carrier frequency offset.

• Atmosphere
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• v.18 no.4
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• pp.493-506
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• 2008

In order to examine the variational features of Asian dust outbreak in recent years, observed WMO synop data were employed for the period from 1996 to 2007. We first divided Asian dust source regions into four subregions; 1) Taklamakan, 2) Gobi, 3) Inner Mongolia-Manchuria and 4) Loess, and the meteorogical variables such as wind speed, precipitation and threshold wind speed observed during the Asian dust outbreak period were compared with those during non-Asian dust period. The results showed that temporal variation of occurrence frequency of dust outbreak had a strong positive correlation with the frequency of strong wind speed and low precipitation in each of the 4 source regions. Spatial distributions of frequency of dust occurrence after 2002 showed increasing trend in Gobi and Inner Mongolia-Manchuria but decreasing trend in Loess region. This is showing a shift in main source region toward Northwest, especially since 2003.

• Journal of the Korean Society of Safety
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• v.16 no.3
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• pp.135-142
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• 2001

This study discusses frequency analysis based on the frequency spectrum and process characterization in orthogonal cutting of Fiber-matrix composite materials. A sparsely distributed idealized composite material, namely a glass reinforced polyester(GFRP) was used as workpiece The present method employs a force sensor and the signals from the sensor are processed using the fast Fourier transform(FFT) technique. The experimental correlations between the different chip formation mechanisms and power spectrum me established. Effects of fiber orientation, cutting parameters and tool geometry on the cutting mechanisms me also discussed.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.385-392
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• 2022

Our society, which has arrived in the 4th industrial revolution, emphasizes covergence education to cultivate creative convergence talents. Therefore, this study is to develop a convergence education program consistent with the direction of the 2019 revised Nuri course and to help teachers who want to implement convergence education. In order to achieve this purpose, in this study, voluntary questions that occurred in play using the educational robot 'Turtle' were classified as STEAM elements. After that, frequency analysis and correlation analysis were conducted. Therefore, this study is meaningful in collecting children's questions about the same robot by age, and it is valuable in establishing future convergence education directions by analyzing the correlation by STEAM elements.