• Restorative Dentistry and Endodontics
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• v.38 no.1
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• pp.31-35
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• 2013

Objectives: This study compared the cyclic fatigue resistance of nickel-titanium (NiTi) files obtained in a conventional test using a simulated canal with a newly developed method that allows the application of constant fatigue load conditions. Materials and Methods: ProFile and K3 files of #25/.06, #30/.06, and #40/.04 were selected. Two types of testing devices were built to test their fatigue performance. The first (conventional) device prescribed curvature inside a simulated canal (C-test), the second new device exerted a constant load (L-test) whilst allowing any resulting curvature. Ten new instruments of each size and brand were tested with each device. The files were rotated until fracture and the number of cycles to failure (NCF) was determined. The NCF were subjected to one-way ANOVA and Duncan's post-hoc test for each method. Spearman's rank correlation coefficient was computed to examine any association between methods. Results: Spearman's rank correlation coefficient (${\rho}$ = -0.905) showed a significant negative correlation between methods. Groups with significant difference after the L-test divided into 4 clusters, whilst the C-test gave just 2 clusters. From the L-test, considering the negative correlation of NCF, K3 gave a significantly lower fatigue resistance than ProFile as in the C-test. K3 #30/.06 showed a lower fatigue resistance than K3 #25/.06, which was not found by the C-test. Variation in fatigue test methodology resulted in different cyclic fatigue resistance rankings for various NiTi files. Conclusions: The new methodology standardized the load during fatigue testing, allowing determination fatigue behavior under constant load conditions.

• Restorative Dentistry and Endodontics
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• v.49 no.2
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• pp.21.1-21.8
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• 2024

Objectives: This paper aims to serve as a useful guide for sample size determination for various correlation analyses that are based on effect sizes and confidence interval width. Materials and Methods: Sample size determinations are calculated for Pearson's correlation, Spearman's rank correlation, and Kendall's Tau-b correlation. Examples of sample size statements and their justification are also included. Results: Using the same effect sizes, there are differences between the sample size determination of the 3 statistical tests. Based on an empirical calculation, a minimum sample size of 149 is usually adequate for performing both parametric and non-parametric correlation analysis to determine at least a moderate to an excellent degree of correlation with acceptable confidence interval width. Conclusions: Determining data assumption(s) is one of the challenges to offering a valid technique to estimate the required sample size for correlation analyses. Sample size tables are provided and these will help researchers to estimate a minimum sample size requirement based on correlation analyses.

• Korean Journal of Community Nutrition
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• v.7 no.4
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• pp.548-558
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• 2002

The purpose of this study was to develop a computer software program for nutritional assessment using a Semi-Quantitative Food Frequency Questionnaire (SQFFQs) and the 24-hour Recall Method. The software for the SQFFQ was divided into input, output, and database. For dietary analyses, recipe and food databases were used. The recipe database included 25 items and the food database was divided into 18 food groups. The food database was composed of 19 general nutrient items, 33 fatty acids, and 18 amino acids. The software developed in this study can be summarized as follows: 1) input items related to the individual s ages information, lifestyle, biological values, and dietary habits; 2) individualized data in percent of the Korean RDA, the energy ratios of carbohydrates, proteins and fats, the ratio of animal to plant source intakes, and the distribution of food group intakes; 3) Statistical data on the individual's information, lifestyle, biological values, and dietary intakes including the frequency of intake of cooked foods, the amounts of food, and the number of food groups, and nutrients. In the 24-hour Recall Method, the input and output consisted of the individual s information and cooked dish intakes. The individual s report included the amounts of nutrient intake according to number of meal and days, in comparison to the Korean RDA, the energy ratio for carbohydrates, proteins and fats, the ratio of animal to plant source intakes, and the distribution of food group intakes. The statistical report presented the number of food groups and foods, and the nutrient intakes. To evaluate the validity of the SQFFQ, the Spearman Rank Order Correlation and kappa values were used. As a result, correlation coefficients comparing the 24-hour Recall Method appeared to be more than 0.5, except for vitamin $B_1, B_2$, niacin, and vitamin E. The kappa values for energy and carbohydrate intakes were both 0.7, and protein, fat, vitamin C, folate, Ca, and iron intakes ranged from 0.3 to 0.7.

• IE interfaces
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• v.24 no.4
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• pp.314-322
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• 2011

This study analyzes a relationship between Data Envelopment Analysis(DEA) efficiency scores and a normalization index in order to examine the validity of DEA models. A normalization index concerned in this study is 'sales per R&D project fund' which is regarded as a crucial R&D project performance evaluation index in practice. For this correlation analysis, three distinct DEA models are selected such as DEA basic model, DEA/AR-I revised model(i.e. DEA basic model with Acceptance Region Type I constraints) and Super-Efficiency(SE) model. Especially, SE model is adopted where efficient R&D projects(i.e. Decision Making Units, DMU's) with DEA efficiency score of unity from DEA basic model can be further differentiated in ranks. Considering the non-normality and outliers, two rank correlation coefficients such as Spearman's ${\rho}_s$ and Kendall's ${\tau}_B$ are investigated in addition to Pearson's ${\gamma}$. With an up-to-date empirical massive dataset of n = 482 R&D projects associated with R&D Loan Program of Korea Information Communication Promotion Fund in the year of 2011, statistically significant (+) correlations are verified between the normalization index and every model's DEA efficiency scores with all three correlation coefficients. Especially, the congruence verified in this empirical analysis can be a useful reference for enhancing the practitioner's acceptability onto DEA efficiency scores as a real-world R&D project performance evaluation index.

• Journal of Digital Convergence
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• v.20 no.4
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• pp.705-713
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• 2022

The purpose of this study is to identify the effect of virtual reality simulation education and intend to present basic data that enables virtual reality simulation education to be used as practical education. Data were collected from April 26 to June 4, 2021 and analyzed by paired t-test, Wilcoxon Signed-Rank Test, Spearman's correlation coefficient using IBM SPSS Statistics 25 program. The results of this study showed that critical thinking disposition, clinical competency, practice satisfaction was improved after virtual reality simulation education. And there were a positive correlation with each other. Virtual reality simulation education is considered a very effective teaching method for nursing students. It is necessary to develop and apply more diverse and systematic scenarios and practice programs in future research.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.6 no.1
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• pp.18-34
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• 1999

Nurse's caring behaviors are essential to help patients cope with their health problems. The purpose of this study was to investigate the importance of nurse's caring behaviors as perceived by staff nurses and patients. The subjects were 295 staff nurses and 340 patients from five medical centers in Taegu. Data collection was done from Dec. 10, 1997 to Jan. 31, 1998. The tool for this study was a 7 point Likert type scale with 27 earing behaviors developed by Lee(1996). Cronbach alpha of the tool was .9701 in staff nurses and .9618 in patients. Data were analyzed with SAS using t-test, ANOVA and Spearman rank correlation program. The results are as follows : 1. The a verage score of perceived importance of nurse's taring behaviors for the 27 items was 5.65 in staff nurses and 4.97 in patients. 2. The most important caring behaviors perceived by the nurses was 'Nurse gives painless and cautious injection and treatment for patients' and for the patients, 'Nurse gives hygienic treatment and nursing care'. 3. The caring behavior which showed a significant difference between the ranks of perceived importance by staff nurses and patients was 'to treat the patient with tenderness and friendship'. 4. The Spearman rank correlation coefficient between the ranks of importance perceived by staff nurses and patients was 0.8302. With the results of this study, the staff nurses could be recognized to have much enthusiasm and passion about caring. It is suggested that nurses let the public know about the nurses' caring roles. In the future, research to investigate the actual practice of nurses' caring behavior is necessary.

• Journal of Korea Water Resources Association
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• v.46 no.2
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• pp.99-109
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• 2013

Increasing complexity of the basin environments makes it difficult for single decision maker to consider all relevant aspects of problem, and thus the uncertainty of decision making grows. This study attempts to develop an approach to quantify the spatial flood vulnerability of South Korea. Fuzzy TOPSIS is used to calculate individual preference by each group and then three GDM techniques (Borda count method, Condorcet method, and Copeland method) are used to integrate the individual preference. Finally, rankings from Fuzzy TOPSIS, TOPSIS, and GDM are compared with Spearman rank correlation, Kendall rank correlation, and Emond & Mason rank correlation. As a result, the rankings of some areas are dramatically changed by the use of GDM techniques. Because GDM technique in regional vulnerability assessment may cause a significant change in priorities, the model presented in this study should be considered for objective flood vulnerability assessment.

• Journal of Korean society of Dental Hygiene
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• v.19 no.6
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• pp.1015-1024
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• 2019

Objectives: This study aimed to examine the correlation between dental care compliance and patients' satisfaction about dental hygienists who are oral health care experts likely to lead patients' motivation. Methods: From June 11 to September 30, 2019, a questionnaire survey was conducted and a total of 189 people completed a structured questionnaire evaluating patient's satisfaction and dental compliance. Data were analyzed using non-parametric tests such as Mann-Whitney test, Kruskal-Wallis rank test, and Spearman's correlation. Results: There was a statistically significant correlation between dental care compliance and the area of good impression (r=0.187, p<0.001), support for interpersonal support (r=0.346, p<0.001), and dissatisfaction (r=0.304, p<0.001). Conclusions: It is necessary to continuously study and identify ways to enhance dental care compliance and patients' satisfaction.

• Journal of KIISE
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• v.44 no.9
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• pp.887-892
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• 2017

Brain-computer interface (BCI) is a technology that controls computer and transmits intention by measuring and analyzing electroencephalogram (EEG) signals generated in multi-channel during mental work. At this time, optimal EEG channel selection is necessary not only for convenience and speed of BCI but also for improvement in accuracy. The optimal channel is obtained by removing duplicate(redundant) channels or noisy channels. This paper propose a dual filter-based channel selection method to select the optimal EEG channel. The proposed method first removes duplicate channels using Spearman's rank correlation to eliminate redundancy between channels. Then, using F score, the relevance between channels and class labels is obtained, and only the top m channels are then selected. The proposed method can provide good classification accuracy by using features obtained from channels that are associated with class labels and have no duplicates. The proposed channel selection method greatly reduces the number of channels required while improving the average classification accuracy.

• Journal of Korean Dental Hygiene Science
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• v.6 no.2
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• pp.141-150
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• 2023

Background: This study was conducted to verify the effectiveness of geriatric dental hygiene education by developing and operating an industrial demand-based curriculum for geriatric dental hygiene. Methods: Wilcoxon signed rank test was performed to verify the before-and-after differences in major competency achievement, geriatric dental hygiene awareness, and class satisfaction according to industrial demandbased field-oriented practical education, and Spearman's correlation analysis was performed to confirm the association between each factor(p<0.05). Results: In the case of major competency achievement, 'communication competence with the older adults' was significantly improved(p=0.031) after conducting industrial demand-based field-oriented practical training. Conclusion: It is believed that the understanding of the older adults and the practical skills for oral care of the older adults can be further developed when the learners are provided with a practical curriculum that can be used in the geriatric industrial field.