• 제목/요약/키워드: Spearman's Rank Correlation

검색결과 168건 처리시간 0.024초

Cyclic fatigue resistance tests of Nickel-Titanium rotary files using simulated canal and weight loading conditions

  • Cho, Ok-In;Versluis, Antheunis;Cheung, Gary S.P.;Ha, Jung-Hong;Hur, Bock;Kim, Hyeon-Cheol
    • Restorative Dentistry and Endodontics
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    • 제38권1호
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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.

An elaboration on sample size determination for correlations based on effect sizes and confidence interval width: a guide for researchers

  • Mohamad Adam Bujang
    • Restorative Dentistry and Endodontics
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    • 제49권2호
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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.

반 정량 식품빈도 조사법 (SQFFQ)과 24시간 회상법을 이용한 영양평가 Software 개발 (Software for Nutritional Assessment Using a Semi-Quantitative Food Frequency Questionnaire and the 24-hour Recall Method)

  • 이상아;이경신;김형숙;이해정;최혜미
    • 대한지역사회영양학회지
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    • 제7권4호
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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.

R&D 프로젝트 성과평가를 위한 DEA모형의 타당성 실증분석 : 정규화지표와의 순위상관을 중심으로 (Empirical Analysis of DEA models Validity for R&D Project Performance Evaluation : Focusing on Rank Correlation with Normalization Index)

  • 박성민
    • 산업공학
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    • 제24권4호
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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.

학습자 중심의 가상현실 시뮬레이션 교육 효과 (Effect of Learner-Centered Virtual Reality Simulation Education)

  • 김성은;김미진
    • 디지털융복합연구
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    • 제20권4호
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    • pp.705-713
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    • 2022
  • 본 연구는 학습자 중심의 가상현실 시뮬레이션 교육의 효과를 확인하기 위한 것이다. 그리고 교육효과 확인을 통해 가상현실 시뮬레이션 교육이 실습교육으로서 활용될 수 있게 하는 기초 자료를 제시하고자 한다. 자료수집은 2021년 4월 26일~6월 4일까지였으며 자료분석은 IBM SPSS Statistics 25 program을 활용하여 paired t-test, Wilcoxon Signed-Rank Test, Spearman's correlation coefficient로 분석하였다. 연구결과 가상현실 시뮬레이션 교육 후 비판적 사고성향, 임상수행능력, 실습만족도가 향상되었고 각각 양의 상관관계가 있는 것으로 나타났다. 가상현실 시뮬레이션 교육은 간호학과 학생에게 효과적인 교수방법이며 향후 다양하고 체계적인 시나리오 및 실습 프로그램을 개발하고 적용해 나갈 필요가 있다.

간호사와 환자가 지각한 돌봄행위 중요도에 관한 연구 (Importance of Nurses's Caring Behaviors as Perceived by Staff Nurses and Patients)

  • 김영이;이병숙
    • 기본간호학회지
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    • 제6권1호
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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.

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홍수 취약성 평가를 위한 그룹 의사결정 접근법 (Group Decision Making Approach to Flood Vulnerability Assessment)

  • 김영규;정은성;이길성;김연주
    • 한국수자원학회논문집
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    • 제46권2호
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    • pp.99-109
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    • 2013
  • 유역 환경에 대한 복잡성의 증가는 단일 의사결정자들이 의사결정문제의 모든 부분을 고려하는 것을 점점 더 불가능하게 만들기 때문에 불확실성은 더욱 증가하게 된다. 따라서 본 연구는 그룹의사결정기법을 사용하여 우리나라 공간적인 홍수 취약성을 정량화하는 접근법을 제시하였다. 개인의 선호도를 분석하기위해 Fuzzy TOPSIS를 사용하였고 개인선호도의 통합을 위해 Borda count, Condorcet 그리고 Copeland 방법을 사용하였다. 마지막으로 도출된 결과를 Fuzzy TOPSIS 및 TOPSIS의 결과와 비교하였고 스피어만 순위상관계수와 켄달의 순위상관계수, Emond와 Mason이 제시한 순위상관분석을 이용하여 순위의 일치성을 검토하였다. 그 결과 일부 지역의 취약성 순위가 큰 폭으로 역전되는 현상을 보였다. 그룹의사결정 개념을 반영하여 지역별 취약성을 산정할 경우 우선순위의 변동이 클 수 있으므로 홍수 취약성 산정시 본 연구에서 제시된 모델을 고려할 필요가 있다.

치과위생사에 대한 환자만족도와 치과 치료지시 이행도의 관계 (Relationship between dental care compliance and patients' satisfaction about dental hygienist)

  • 김선영
    • 한국치위생학회지
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    • 제19권6호
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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.

동작 상상 EEG 분류를 위한 이중 filter-기반의 채널 선택 (A Dual Filter-based Channel Selection for Classification of Motor Imagery EEG)

  • 이다빛;이희재;박상훈;이상국
    • 정보과학회 논문지
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    • 제44권9호
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    • pp.887-892
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    • 2017
  • 뇌-컴퓨터 인터페이스는 정신 작업 동안 다채널에서 생성된 뇌파의 신호를 측정, 분석하여 컴퓨터를 제어하거나 의사를 전달하는 기술이다. 이때 최적의 뇌파 채널 선택은 뇌-컴퓨터 인터페이스의 편의성과 속도뿐만 아니라 정확도 향상을 위해 필요하다. 최적의 채널은 중복 채널들 또는 노이즈 채널들을 제거함으로써 얻는다. 이 논문에서는 최적 뇌파 채널을 선택하기 위해 이중 filter-기반의 채널 선택 방법을 제안한다. 제안한 방법은 먼저 채널들 간의 중복성을 제거하기 위해 spearman's rank correlation을 사용하여 중복 채널들을 제거한다. 그 뒤, F score를 이용하여 채널과 클래스 라벨 간의 적합성을 측정하여 상위 m개의 채널들만을 선택한다. 제안한 방법은 클래스 라벨과 관련되고 중복이 없는 채널들을 사용함으로써 좋은 분류 정확도를 이끌어 낼 수 있다. 제안한 채널 선택 방법은 채널의 수를 상당히 줄임과 동시에 평균 분류 정확도를 향상시켰다.

산업체 수요기반의 노인치위생학 및 실습 교육과정 운영 사례 연구 (A Case study on geriatric dental hygiene and practical education courses based on industry demand)

  • 최용금;윤지혜
    • 대한치위생과학회지
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    • 제6권2호
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    • pp.141-150
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    • 2023
  • 연구의 배경 및 목적: 본 연구에서는 노인구강관리에 대한 산업체 수요기반의 교육과정을 개발하여 운영함으로써 노인치위생학 교육의 효과를 확인해 보고자 진행하였다. 연구방법: 산업체 수요기반 현장중심 실무교육에 따른 전공역량달성도, 노인치위생과정 인식, 수업만족도의 전후차이를 검증하기 위하여 비모수 분석으로 윌콕슨 부호순위 검정(Wilcoxon signed rank test)을 수행하였으며, 각 요인간의 연관성을 확인하기 위해 스피어만 상관분석(Spearman's correlation analysis)을 수행하였다(p<0.05). 결과: 전공역량달성도의 경우 산업체 수요기반 현장중심 실무교육을 수행 후 '노인과의 의사소통 역량'이 유의미하게 향상되었다(p=0.031). 고찰: 노인치위생학 교육과정은 산업체 현장에서 활용가능한 실무중심의 교육과정이 학습자에게 제공되었을 때 노인에 대한 실제적인 이해와 노인구강관리에 대한 현장실무전공역량이 더욱 개발될 수 있을 것으로 판단된다.