• Biomedical Science Letters
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• v.28 no.3
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• pp.178-185
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• 2022

The purpose of this study was to analyze the effect of chewing difficulty on osteoarthritis in Korean adults. Data from the National Health and Nutrition Examination Survey for two years from 2019 to 2020. The collected data were analyzed using the SPSS (21.0) program using composite samples, and the mean crossover analysis and logistic return analysis were performed. An analysis of the effects of chewing difficulty on osteoarthritis in korean adults showed that those with chewing difficulty had a 2.02 fold higher risk of osteoarthritis (95%CI=1.56~2.42) and a statistically significant difference (P<0.05). The association between the chewing difficulty on osteoarthritis could be confirmed, and measures improve of the oral health and preventing osteoarthritis should be prepared.

• Journal of Korean society of Dental Hygiene
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• v.21 no.5
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• pp.601-610
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• 2021

Objectives: The purpose of this study was to analyze the effect of chewing difficulty on depression in Korean adults to provide basic data on improving the quality of life related to oral health of Korean adults. Methods: The raw data of the analysis were obtained from the dataset of the seven Korea National Health and Nutrition Examination Survey conducted between 2016 and 2018. The subjects included 9,535 people who underwent oral examination and answered questions. The collected data were analyzed using the SPSS (ver 21.0) program using composite samples, and the mean crossover analysis and logistic return analysis were performed. Results: An analysis of the effects of chewing difficulty on depression in Korean adults showed that those with chewing difficulty had a 2.24 fold higher risk of depression (95% CI: 1.73-2.90) and a statistically significant difference (p<0.05). Conclusions: The association between the chewing difficulty on depression could be confirmed, and measures improve of the oral health and preventing depression should be prepared.

• Journal of Biomedical Engineering Research
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• v.29 no.1
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• pp.73-81
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• 2008

The purpose of this study is to observe the brain activity patterns during visual oddball tasks with two difficulty levels by the analysis of high-density event-related potential (ERP). Along with conventional statistical analysis of averaged ERP waveforms, we applied independent component analysis (ICA) for the individual, single-trial analysis and verified its effectiveness. We could identify multiple ERP components such as early visual components (P1, N1), and two components which seem to be important task-related components and showed difficulty-dependent variability (P2, P300). The P2 was found around central region at $180{\sim}220ms$, and the P300 was found globally at $300{\sim}500ms$ poststimulus. As the task became difficult, the P2 amplitude increased, and the P300 amplitude decreased. After single-trial ERPs were decomposed into multiple independent components (ICs), several ICs resulting from P2 and P300 sources were identified. These ICs were projected onto scalp electrodes and the projected ICs were statistically compared according to two task difficulties. For most subjects, the results obtained from single-trial/individual analysis using ICA gave the tendencies of amplitude change that are similar to the averaged ERP analysis for most subjects. The temporal pattern and number of ICs corresponding to ${\mu}$ rhythm was not dependent on the task difficulty. It seems that the motor response was not affected by the task difficulty.

• Journal of the Korea Society of Computer and Information
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• v.21 no.4
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• pp.39-46
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• 2016

While the difficulty of the music can be classified by a variety of standard, conventional methods are classified by the subjective judgment based on the experience of many musicians or conductors. Music score is difficult to evaluate as there is no quantitative criterion to determine the degree of difficulty. In this paper, we propose a new classification method for determining the degree of difficulty of the music. In order to determine the degree of difficulty, we convert the score, which is expressed as a traditional music score, into electronic music sheet. Moreover, we calculate information about the elements needed to play sheet music by distance of notes, tempo, and quantifying the ease of interpretation. Calculating a degree of difficulty of the entire music via the numerical data, we suggest the difficulty evaluation of the score, and show the difficulty of music through experiments.

• Journal of Korean society of Dental Hygiene
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• v.21 no.4
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• pp.383-391
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• 2021

Objectives: Based on the 7th National Health and Nutrition Examination Survey 1,135 adults aged 19 years were selected as the final study subjects to investigate the relationship between oral health and chewing difficulty in adults. Methods: Frequency analysis, chi-square test, and logistic regression analysis were performed for general characteristics, oral health behaviors, awareness symptoms, and oral health using SPSS Program 21.0. Results: Regarding factors related to chewing difficulty, the oral health was 0.44 times lower than the average level and 0.28 times lower than the good condition. In the case of oral examination, chewing difficulty was 0.85 times lower. The speaking problem was 0.11 times lower in usually than inconvenient and 0.06 times lower in not inconvenient. In the case of un-treatment, it was 0.40 times lower than that in the case of treatment. The chewing difficulty was significantly higher by 2.09 times in the case of experience of tooth pain and 1.36 times in the case of periodontal disease. Conclusions: Based on the above results, it is thought that prevention and treatment are actively needed to identify factors of oral health to improve oral health, to solve chewing difficulty and to improve chewing function.

• Journal of Educational Research in Mathematics
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• v.14 no.1
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• pp.71-88
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• 2004

The purpose of this study was to examine particular variables that play a significant role in the difficulty of math test items in College Scholastic Ability Test (CSAT). The study also aimed to develop a model of measuring the item difficulty. Variables correlated to item difficulty were drawn from the review of the related literature and the analysis of the content and difficulty of the past test items of CSAT. The first instrument was designed by using the correlated variables. According to the results of correlation analysis, the second instrument was made by deleting the variables which showed relatively low correlation with item difficulty and by refining some variables. Several models were proposed by using the revised instrument. The comparison of the R square and cross validity of each model reveals that integrated regression model was the most stable and accurate among the proposed models. The study also showed that statistically significant predictors were choice format, content domain, behavior domain, and the degree of item familiarity in the order of proportion of variance accounted by the predictors. Despite the limited scope of the present research, it can be suggested that its findings provide useful insights into predicting math test item difficulty.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.214-215
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• 2013

Recently, Construction industry has been trying to reduce environmental impacts reflecting the global trend 'Green Growth'. However most of previous studies focused on operation & maintenance phases and do not have been approached construction phases. In addition, environmental management factors by project participants are assessed with only weight of factors, overlooking these work difficulty. Therefore This study aims to deducted the critical environmental management factors by project participants considering work difficulty in plan, design and construction phase. The basis data is collected through literature reviews and interview targeting each project participant and analyze these data using importance-difficulty analysis(IDA).

• The Mathematical Education
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• v.52 no.1
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• pp.1-17
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• 2013

The goal of the textbooks of 2009 revised curriculum is to make customized lectures possible considering learning characteristics and understanding level of students. However, it is not easy to find a research result on sensed difficulty of the mathematics textbook, which is able to provide valuable information on the development of the diverse level textbooks. This research suggested criteria in analysing sensed difficulties of field teachers on the textbooks, and analysed sensory difficulty on the selective tracks textbooks based on 2007 revised mathematics curriculum using the criteria. The results of the analysis on 59 mathematics selective tracks textbooks show that all have average sensed difficulty. The criteria and research results are expected to provide valuable information in future mathematics textbook development.

• Korean Journal of Biological Psychiatry
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• v.20 no.2
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• pp.40-44
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• 2013

Objectives The purpose of this study was to examine the differences according to depressive symptom-related difficulty status. Methods 2828 participants were a divided into depressive symptom-related difficulty group (difficult group, n = 774), and a non-depressive symptom-related difficulty group (not difficult group, n = 2054). The psychological character of the participants were assessed using the Korean version of the Patient Health Questionnaire-9 (PHQ-9), Satisfaction with Life Scale (SWLS), the 12-item General Health Questionnaire (GHQ-12), and Conner-Davidson Resilience Scale (CD-RISC). Statistical analyses were done using t-test, chi-square, and analysis of covariance (ANCOVA). Results Compared with the no difficulty group, the difficulty group reported significantly higher score in all items of PHQ-9. The score of "feeling tired" was the highest and the score of "suicidal ideation" is the lowest in both groups. ANCOVA analysis that is adjusted with the total score of PHQ-9 showed the differences in SWLS, GHQ-12, and CD-RISC scores between the difficulty group and the no difficulty group. Conclusions The findings suggest that there are different characters on PHQ-9, SWLS, GHQ-12, and CD-RISC according to depressive symptom-related difficulty. Therefore, it is required not only to evaluate depressive symptoms in patients with depression, but also the depressive symptom-related difficulty to understand these differences.

• The Journal of Health Technology Assessment
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• v.6 no.2
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• pp.100-105
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• 2018

Objectives: The purpose of this research is to investigate regional variations of mastication difficulty rates in the elderly over 65 in 229 primary autonomous districts in Korea and explore relevant characteristics. For the research data, local community health survey conducted in 2015 and data from Ministry of the Interior and Safety, Ministry of Health & Welfare, National Health Insurance Service and Statistics Korea were used. Methods: Frequency analysis was conducted for general characteristics and mastication difficulty rates of each region, and distribution of mastication difficulty rates was displayed for each town, city and province by mapping them. Extremal quotient (EQ), coefficient of variation (CV) values were calculated for regional variations, and logistic regression analysis was performed to reveal the relationship between each independent variable and mastication difficulty rates. Results: The average of standardized mastication difficulty rate was 46.78%, and regional variations were significant with EQ 3.46, CV 0.18. Characteristic factors that have significant effects on mastication difficulty rate included sex ratio, elderly population and the number of dentists per 10000 people. Conclusion: As a result, there were variations among mastication difficulty rates in 229 primary local governments across the country, and the distribution of health care resources by the characteristics of the local environment by region affected mastication difficulty rates. Accordingly, it is required to provide political supports to overcome regional inequality of oral health levels and develop cooperative system between local governments and local dentists.