• 약학회지
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• 제45권3호
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• pp.310-319
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• 2001

To compare skin irritation and cytotoxicity of anti-wrinkle agents, we examined skin irritation of six anti-wrinkle agents (ascorbic acid, glycolic acid, all trans-retinoic acid, ginseng extract, retinol, EB) in New Zealand white rabbit. Cytotoxicity of these agents was determined by MTT [tetrazolium salt 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] at multi-time points in cultured HaCaT cell, a human immortalized keratinocyte cell. We then analyzed correlation between skin irritation and cytotoxicity by spearman's rank correlation analysis. All trans-retinoic acid showed the highest primary irritation index (0.92) in skin irritation test. Being all the six agents not irritant, retinal showed the most cytotoxic agents. The correlation between skin irritation and cytotoxicity ($IC_{50}$/ at different time point was 0.814, 0.757, 0.814 and 0.7 at 3, 24, 48 and 72 h, respectively. We also fecund that IC$_{20}$ and IC$_{80}$ of these agents showed similar correlation with skin irritation. These results therefore demonstrated that there is close correlation between skin irritation and cytotoxicity $IC_{50}$/ value by MTT in HaCaT cell at early time points by anti-wrinkle agents or IC$_{20}$ value. $IC_{50}$/ at earily time point or IC$_{20}$ values may be reliable alternative determinant of skin irritation.n.

• 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.

• 한국경영과학회지
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• 제20권3호
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• pp.123-146
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• 1995

Several quality control schemes have been extensively compared using multivariate normal data sets simulated with various correlation structures. They include multiple univariate CUSUM charts, multivariate EWMA charts, multivariate CUSUM charts and Shewhart T$^{3}$ chart. This paper considers a new approach of the multivariate EWMA chart, in which the smoothing matrix has full elements instead of only diagonal elements. Performance of the schemes is measured by avaerage run length (ARL), coefficient of variation of run length (CVRL) and rank in order of signaling of off-target shifts in the process mean vector. The schemes are also compared by noncentrality parameter. The multiple univariate CUSUM charts are generally affected by the correlation structure. The multivariate EWMA charts provide better ARL performance. Especially, the new EWMA chart shows remarkable results in small shifts.

• 대한기계학회논문집B
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• 제38권2호
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• pp.129-137
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• 2014

본 연구에서는 바이오디젤연료 혼합비변화에 대한 디젤엔진의 배기특성에 대해 조사하였다. 실험에 사용된 연료는 경유와 바이오디젤(폐식용유) 혼합연료 BD3, BD5, BD20, BD50 및 BD100을 사용하였으며, 실험변수로서 분사압력(${\Delta}p_{inj}$)을 400bar, 600bar, 800bar, 1000bar 및 1200bar로 설정하였다. 분사압력과 바이오디젤 혼합연료 혼합비에 따른 정량적인 NOx와 Soot의 배기특성 해석을 위하여 통계학에 기초한 피어슨 상관계수와 스피어만 상관계수의 개념을 도입하였다. 본 연구의 결과로서 실험 조건 전체에 대한 피어슨 상관계수는 -0.732, 스피어만 상관계수는 -0.724로 NOx와 Soot 발생의 상관관계가 선형적이다. 특히 분사압력 800bar 조건에서 피어슨 상관계수가 -0.089으로 NOx와 Soot 배출량 상관관계가 0에 가깝기 때문에, 바이오디젤 연료 혼합비 제어를 통한 NOx와 Soot의 동시저감이 가능하다고 판단된다.

• Journal of Acupuncture Research
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• 제23권1호
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• pp.155-164
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• 2006

Objectives : The aim of this study is to validate the correlation between Assessment Instruments of Knee OA and digital infrared thermographic imaging(DITI) and to find out the methods to assess knee OA by DITI. Methods : 60 subjects were evaluated. They were asked to answer VAS pain scale, WOMAC, KHAQ and LFI. Correlation was assessed by examining the spearman's rank correlation coefficients. Results : VAS, WOMAC and LFI was correlated with not only the thermal difference between Ant. knee and Post. knee, but also the lowest temperature of Ant. knee. Conclusion: DITI value was useful for evaluating the degree of OA. And we should find out that decrease of pain is correlated with change of DITI value.

• Asian Pacific Journal of Cancer Prevention
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• 제16권1호
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• pp.355-361
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• 2015

Background: Deletion types of genetic variants of glutathione S-transferase (GST) M1 and T1, the GSTM1 null and GSTT1 null which are risk factors for certain cancers, have been ubiquitously found in human populations but their worldwide distribution pattern is unclear. Materials and Methods: To perform a meta-analysis, a systematic search for the literature on GSTM1 and GSTT1 null genotypes was done to identify 63 reports for 81 human populations. Relationships between the GSTM1 and GSTT1 null genotype frequencies and the absolute latitude of 81 populations were tested by Spearman's rank correlation coefficient. Results: A significant positive correlation was detected between the GSTM1 null genotype frequency and the absolute latitude (r=0.28, p-value <0.05), whereas the GSTT1 null genotype frequency and absolute latitude showed a significant negative correlation (r= -0.41 p-value <0.01). There was no correlation between the frequencies of GSTM1 and GSTT1 null genotype in each population (r= -0.029, p-value=0.80). Conclusions: Latitudinal clines of the distribution of the GSTM1 and GSTT1 null genotypes may be attributed to the result of gene-environmental adaptation. No functional compensation between GSTM1 and GSTT1 was suggested by the lack of correlation between the null frequencies for GSTM1 and GSTT1.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1998년도 학술발표대회 논문집 제17권 1호
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• pp.221-224
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• 1998

간섭신호가 원하는 신호에 coherent한 경우에는 원하는 신호와 간섭신호간의 cross correlation에 의해 공분산 행렬의 rank가 줄어들게 되어 coherent한 간섭신호의 도래각을 추정할 수 없게 된다. 이러한 문제를 해결하기 위해 발표된 기존의 방법중 대칭 어레이(Symmetric array)방법은 계산량이 많아지고 공간 스무딩(Spatial Smoothing)방법은 array aperture size에서 손해를 보게 되어 분해능이 떨어지는 단점이 있다[1,2,3].

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 추계종합학술대회
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• pp.328-331
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• 2007

본 논문은 Correlated MIMO-OFDM 페이딩 채널을 위한 클러스터 응답 모델의 용량에 대한 연구이다. 송신기에서 채널 정보를 알고 있는 경우와 채널 정보를 모르는 경우를 고려하여, 수신기의 correlation에 의한 용량과 송${\cdot}$수신기 양쪽의 correlation에 의한 용량을 비교 한다. 결과로부터 수신기의 correlation에 의한 용량이 송${\cdot}$수신기의 correlation에 의한 용량보다 더 좋은 것을 확인 할 수 있다. 또한 Water-filling 방법을 사용하여 송신 안테나에 파워를 할당한 경우 균일한 파워를 할당한 경우보다 Water-filling 이득에 의해 더 큰 용량을 가지는 것으로 나타난다. 그러나 클러스터의 수가 correlation 행렬의 최대 랭크보다 크고 SNR이 높은 영역인 경우 Water-filling에 의한 이득이 거의 없음을 보인다.

• 정보관리학회지
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• 제18권4호
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• pp.103-125
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• 2001

이 연구는 86개 4년제 대학도서관을 대상으로 장서개발을 관련 요소와 유형별 장서규모간의 상관관계와 상관계수의 차의 유무를 구명한 것이다. 이 연구의 결과는 다음과 같다. 상관분석 결과 도서와 연속간행물은 설립자별에 따라 1∼2개 요소를 제외하고 모두 정(正)의 상관관계를, 비도서자료는 대부분 무상관을 나타냈다. 그리고 국공립대와 사립대의 상관계수 순위는 연속간행물이 61%의 일치도를 보인 반면, 도서는 거의 무일치로 나타났다. 상관계수간의 차이 분석결과 요소별로는 총 도서수만 상당수의 요소들이 뚜렷한 차를 나타냈고, 장서유형별로는 총 도서수와 연간 도서증가량간에는 대부분의 요소가 총 도서수와, 연간 도서증가량과 연속간행물간에는 2∼3개의 요소가 연속간행물과, 총 도서수와 연속간행물간에는 대부분의 요소가 총 도서수와 더 높은 관계를 나타냈다.

• The Journal of Korean Physical Therapy
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• 제24권5호
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• pp.325-333
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• 2012

Purpose: The purpose of this study was to determine the concurrent validity between Figure-of-8 Walking Test (F8W), Berg Balance Scale (BBS), Four Squared Step Test (FSST), and Timed UP and GO Test (TUG) in patients with stroke. Methods: Forty two participants (26 men, 16 women, $55.0{\pm}11.72$) with at least three months post stroke who were able to walk at least 10 m without walking aid participated in this study. Assessment of concurrent validity between the F8W (time and steps) and BBS was performed using Spearman rank order correlation and between the F8W (time and steps), FSST and TUG assessed using Pearson correlation. Results: The time of the F8W showed correlation with BBS (r=-0.46, p<0.01), FSST (r=0.64, p<0.01), and TUG (r=0.81, p<0.01), and steps of the F8W showed correlation with BBS (r=-0.43, p<0.01), FSST (r=0.47, p<0.01), and TUG (r=0.51, p<0.01). Conclusion: The F8W is a valid measure of balance and walking skill among patients with stroke and may provide complementary information with regard to dynamic balance and functional walking for the real life of stroke patients.