• 제목/요약/키워드: linear correlation coefficient

검색결과 770건 처리시간 0.029초

공복혈당수치와 운동유발전위의 상관관계에 대한 후향적 분석 : 중추운동신경과 말초운동신경의 비교 (A Retrospective Study on the Correlation between Fasting Blood Sugar and Motor Evoked Potentials : Comparison between Central and Peripheral Motor Nerve)

  • 나병조;박성욱;정우상;문상관;박정미;고창남;조기호;김영석;배형섭;홍진우
    • 대한한방내과학회지
    • /
    • 제28권3호
    • /
    • pp.434-441
    • /
    • 2007
  • Objectives : Peripheral neurodegeneration occurs in diabetes mellitus (DM), both sensory and motor nerve. but we don't know exactly if DM affects central nerve pathway for all studies. Electrophysiologic study is one of the most important diagnostic tools for diabetic neuropathy. Electroneurography and electromyography are usually used. but evoked potentials (EP) is more sensitive to small nerve fiber damages and useful for central nerve evaluation in addition to peripheral nerves. Most diabetic neuropathy studies by EP have been performed with somatosensory evoked potentials (SSEP). In contrast, the objective of this study is to investigate if DM targets central motor neurons by assessing the relation between fasting blood sugar (FBS) and motor evoked potentials (MEP) latency. Methods : We inspected the medical records of 34 patients who had MEP tests during admitting days. The latency from cervical portion to abductor pollicis brevis was used as peripheral motor conduction time (PMCT). and the latency from vertex to cervical portion was used as central motor conduction time (CMCT). Then, they were correlated to FBS using correlation analysis. Results : There was a significant linear relation between FBS and PMCT (Pearson's correlation coefficient r=0.487, p<0.01), but a poor linear relation between FBS and CMCT (Pearson's correlation coefficient r=-0.l97. p>0.05). Conclusions : This study suggests that prolonged latencies of MEP in DM may be due to peripheral neuropathy rather than dysfunction of central motor pathway. therefore the clinical use of MEP to diabetic neuropathy has to be divided segmentally.

  • PDF

용적맥파 해석에 의한 동맥 혈관 특성화 연구 (A Study on Arterial Characterization by Photoplethysmography Analysis)

  • 한상휘;변미경;김정국;허웅
    • 전자공학회논문지SC
    • /
    • 제41권5호
    • /
    • pp.65-70
    • /
    • 2004
  • 본 논문에서는 4채널 용적맥파 신호를 이용하여 혈관의 노화 정도 및 경화 정도와 관련있는 동맥 혈관의 특성을 분석하는 새로운 방법을 개발하고 그 효용성을 평가하였다. 이를 위하여 지첨과 족지첨에서 계측한 맥파 신호를 이용하여 맥파 전달 시간차를 분석 파라메터로 선정하였다. 개발한 시스템의 효용성을 확인하기 위해, 9세에서 83세까지 총 51명의 피검자(남성 26명, 여성 25명)를 대상으로 용적맥파 신호를 4지점에서 동시에 측정한 다음, 선형 회귀 분석법을 사용하여 연령과 분석 파라메터 사이의 상관성을 평가하였다. 연령에 따른 파라메터의 선형 회귀 분석 결과는 연령에 따라 감소하는 경향을 보였다. 51명의 데이터에서 얻어진 상관 계수는 좌측에서 -0.79770을 보였으며, 우측에서는 -0.80599를 보여 높은 상관 관계를 보였다. 또한 피검자의 신장으로 정규화하여 얻어진 상관 계수는 좌측에서 -0.81345, 우측에서 -0.81605로 약간 향상된 상관 계수를 보였다.

Vitamin C Tablet Assay by Near -Infrared Reflectance spectrometry

  • Kargosha, Kazem;Ahmadi, Hamid;Nemati, Nader
    • 한국근적외분광분석학회:학술대회논문집
    • /
    • 한국근적외분광분석학회 2001년도 NIR-2001
    • /
    • pp.4111-4111
    • /
    • 2001
  • When a drug is prepared in a tablet, the active component represents only a small portion of the dosage form. The other components of the formulation include materials to assist in the dissolution, antioxidants, coloring agents and bulk fillers. The tablets are tested using approved testing methods usually involving separation and subsequent quantification of the active component. Tablets may also be tested by near-Infrared Reflectance spectrometry (NIRS). In the present study, based on NIRS and multivariate calibration methods, a novel and precise method is developed for direct determination of ascorbic acid in vitamin C tablet. Two different tablet formulations were powdered in three different sizes, 63-125 ${\mu}{\textrm}{m}$, and examined. Spectral region of 4750-4950 $cm^{-1}$ / was used and optimized for quantitative operations. Partial least squares (PLS) and multiple linear regression (MLR) methods were performed for this spectral region. The results of optimized PLS and MLR methods showed that reproducibility increase with decreasing grain size and standard error of calibration (SEP) of less than 1% w/w of ascorbic acid and a correlation coefficient of 0.998 can be achieved. The PLS method showed better results than MLR. Seven overdose and underdose samples (prepared in the laboratory to match marketed products) were tested by proposed and iodometric standard methods. A correlation between NIRS predicted ascorbic acid values and iodomet.ic values was calculated ($R^2$=0.9950). Finally, the direct analysis of individual intact tablets in their unit-dose packages (Blistering in aluminum and PVC foils) obtained from market were also carried out and a correlation coefficient of 0.9989 and SEP of 0.931% w/w of ascorbic acid were achieved.

  • PDF

Dependence of Geomagnetic Storms on Their Assocatied Halo CME Parameters

  • 이재옥;문용재;이경선;김록순
    • 천문학회보
    • /
    • 제37권1호
    • /
    • pp.95.2-95.2
    • /
    • 2012
  • We have compared the geoeffective parameters of halo coronal mass ejections (CMEs) to predict geomagnetic storms. For this we consider 50 front-side full halo CMEs whose asymmetric cone model parameters and earthward direction parameter were available. For each CME we use its projected velocity (Vp), radial velocity (Vr), angle between cone axis and sky plane (${\gamma}$) from the cone model, earthward direction parameter (D), source longitude (L), and magnetic field orientation (M) of the CME source region. We make a simple and multiple linear regression analysis to find out the relationship between CME parameters and Dst index. Major results are as follows. (1) $Vr{\times}{\gamma}$ has a higher correlation coefficient (cc = 0.70) with the Dst index than the others. When we make a multiple regression of Dst and two parameters ($Vr{\times}{\gamma}$, D), the correlation coefficient increases from 0.70 to 0.77. (2) Correlation coefficients between Dst index and $Vr{\times}{\gamma}$ have different values depending on M and L. (3) Super geomagnetic storms (Dst ${\leq}$ -200 nT) only appear in the western and southward events. Our results demonstrate that not only the cone model parameters together with the earthward direction parameter improve the relationship between CME parameters and Dst index but also the source longitude and its magnetic field orientation play a significant role in predicting geomagnetic storms.

  • PDF

Examination of Correlations Between Several Biochemical Components and Powdery Mildew Resistance of Flax Cultivars

  • Aly, Aly A.;Mansour, Mahmoud T. M.;Mohamed, Heba I.;Abd-Elsalam, Kamel A.
    • The Plant Pathology Journal
    • /
    • 제28권2호
    • /
    • pp.149-155
    • /
    • 2012
  • A field trial was conducted in 2009/2010 and 2010/2011 growing seasons at Giza Agricultural Research Station to examine correlations between some biochemical componets and powdery mildews ($PM_s$) resistance in flax cultivars. Nine flax cultivars could be divided into five distinct groups, i.e., highly susceptible (Cortland and C.I. 2008), moderately susceptible (Giza 7, and Marshall), moderately resistant (Cass), resistant (Koto, Dakota and Wilden), and highly resistant (Ottowa 770B). The cultivars showed considerable variation in PM severity ranged from 8.05 on Ottowa 770B to 97.02% on Cortland. Total soluble proteins, total phenols, antioxidant enzymes (peroxidase and polyphenoloxidase), ascorbic acid, tocopherol, and malondialdehyde (MDA), were determined in uninfected leaves of the tested cultivars. Pearson's correlation coefficient was calculated to measure the degree of association between PM severity and each component. All components showed significant (P < 0.05) or highly significant (P < 0.01) negative correlation with PM severity except MDA, which showed positive correlation (P < 0.01). Linear regression analysis was used to evaluate the causal relationship between the biochemical components (independent variables) and PM severity (dependent variable). Coefficient of determination ($R^2$) values of the generated models ranged from 48.76 to 77.15%. Tocopherol, MDA, and proteins were the most important contributors to the total variation in PM severity as the $R^2$ values of their models were 71.78, 75.28, and 77.15%, respectively. The results of the present study suggest that tocopherol, MDA, and proteins in uninfected leaves can be used as biochemical markers to predict PM resistance in flax.

치매전문요양보호사의 치매 지식, 공감 및 치매에 대한 태도 (A Study of Knowledge about Dementia, Empathy and Attitudes toward Dementia in Caregivers of Older Adults with Dementia)

  • 박아영
    • 디지털융복합연구
    • /
    • 제16권1호
    • /
    • pp.389-397
    • /
    • 2018
  • 본 연구는 치매전문요양보호사의 치매에 대한 태도에 영향을 미치는 요인을 확인하여 치매돌봄서비스 질을 향상시킬 수 있는 근거자료를 마련하기 위한 서술적 조사연구이다. G시와 J도에 소재한 요양센터에 근무하는 치매전문요양보호사 147명을 대상으로 하였으며, 구조화된 설문지로 설문을 수집하였다. 수집된 자료는 SPSS Win 21.0을 이용하여, 기술통계, Pearson correlation coefficient, Multiple linear regression 등의 방법으로 분석하였다. 연구결과 치매지식 점수는 30점 만점에 평균 $20.18{\pm}3.58$점, 공감은 105점 만점에 평균 $83.12{\pm}9.68$점, 치매에 대한 태도는 140점 만점에 평균 $96.45{\pm}13.72$점이었다. 치매에 대한 태도는 연령, 직업동기에서 유의한 차이를 나타내었으며, 지식 및 공감과 모두 양의 상관관계가 있었다. 태도에 영향을 미치는 주요변인은 공감으로 설명력은 28.6%였다. 연구결과를 토대로 요양보호사의 연령, 동기, 공감에 따른 치매전문교육프로그램을 실시할 것을 제언한다.

비선형 평활화와 다차원의 명암변화에 기반을 둔 영상인식 (Image Recognition Based on Nonlinear Equalization and Multidimensional Intensity Variation)

  • 조용현
    • 한국지능시스템학회논문지
    • /
    • 제24권5호
    • /
    • pp.504-511
    • /
    • 2014
  • 본 논문에서는 영상의 비선형 평활화와 다차원의 명암변화에 기반을 둔 조합형 인식기법을 제안하였다. 여기서 비선형 평활화는 적응적 변형의 히스토그램 재조정 전처리 기법으로 영상의 밝기를 조정하여 화질을 개선하기 위함이다. 다차원의 명암변화는 인접 픽셀간의 밝기변화를 4단계로 나누어 고려함으로써 영상의 속성을 더욱 더 정확하게 반영하기 위함이고, x축과 y축의 2방향 각각의 명암변화를 고려한 정규상호상관계수는 좀 더 포괄적으로 영상의 유사성을 측정하기 위함이다. 제안된 기법을 50개 40*40 픽셀의 명암도 변화를 가지는 얼굴영상들을 대상으로 실험한 결과, 평활화를 수행하지 않거나 선형 평활화를 수행한 기법에 비해 각각 영상의 속성을 잘 반영한 우수한 인식성능이 있음을 확인하였다.

보행 시 퇴행성 관절염 환자의 동적 안정성 분석 (Dynamic Stability Analysis of Patients with Degenerative Osteoarthritise during Walking)

  • 류지선
    • 한국운동역학회지
    • /
    • 제18권1호
    • /
    • pp.21-30
    • /
    • 2008
  • 이 연구는 60대 남자 노인의 정상인들과 무릎 관절염 환자들 사이에 보행 시 국부적인 안정성을 비교하기 위해 선형기법의 변이 계수와 비선형 시계열 동역학 기법의 Lyapunov지수(LyE) 및 상관차원(correlation dimension, COD) 방법을 적용해 분석했다. 분석 결과 선형 운동인 발목의 수직 변위를 통해 관찰한 국부적 안정성은 선형 기법의 변이 계수를 통해 관찰한 결과 정상인 집단이 무릎관절염 환자 집단보다 불안한 것으로 나타난 반면에 비선형 기법 관찰에서는 두 집단 차이가 없는 것으로 나타났다. 한편 각형 운동인 무릎의 각 변위를 통해 분석된 국부적 안정성은 선형 분석 결과는 두 집단 차이점을 보이지 않았지만, 비선형 기법 결과인 COD 지수는 무릎 관절염 환자가 크게 나타나 결과적으로 보행 시 국부적 불안을 보였다. 이상 본 연구 결과를 종합해 보면 선형 기법의 결과와 비선형 기법의 결과는 일치하지 않았으며, 또한 무릎 관절염 환자의 보행 시 불안정은 발목의 수직 변위인선형에서 보다 무릎 관절 각 변위인 각형에서 뚜렷하게 나타났다.

최적선형필터를 이용한 망막신경절세포 Spike Train으로부터의 시각자극 세기 변화 추정 (Estimation of Visual Stimulus Intensity From Retinal Ganglion Cell Spike Trains Using Optimal Linear Filter)

  • 류상백;김두희;예장희;김경환;구용숙
    • 대한의용생체공학회:의공학회지
    • /
    • 제28권2호
    • /
    • pp.212-217
    • /
    • 2007
  • As a preliminary study for the development of electrical stimulation strategy of artificial retina, we set up a method fur the reconstruction of input intensity variation from retinal ganglion cell(RGC) responses. In order to estimate light intensity variation, we used an optimal linear filter trained from given stimulus intensity variation and multiple single unit spike trains from RGCs. By applying ON/OFF stimulation(ON duration: 2 sec, OFF duration: 5 sec) repetitively, we identified three functional types of ganglion cells according to when they respond to the ON/OFF stimulus actively: ON cell, OFF cell, and ON-OFF cell. Experiments were also performed using a Gaussian random stimulus and a binary random stimulus. The input intensity was updated once every 90 msec(i. e. 11 Hz) to present the stimulus. The result of reconstructing 11 Hz Gaussian and binary random stimulus was not satisfactory and showed low correlation between the original and reconstructed stimulus. In the case of ON/OFF stimulus in which temporal variation is slow, successful reconstruction was achieved and the correlation coefficient was as high as 0.8.

Correlation between Colon Transit Time Test Value and Initial Maintenance Dose of Laxative in Children with Chronic Functional Constipation

  • Kim, Mock Ryeon;Park, Hye Won;Son, Jae Sung;Lee, Ran;Bae, Sun Hwan
    • Pediatric Gastroenterology, Hepatology & Nutrition
    • /
    • 제19권3호
    • /
    • pp.186-192
    • /
    • 2016
  • Purpose: To evaluate the correlation between colon transit time (CTT) test value and initial maintenance dose of polyethylene glycol (PEG) 4000 or lactulose. Methods: Of 415 children with chronic functional constipation, 190 were enrolled based on exclusion criteria using the CTT test, defecation diary, and clinical chart. The CTT test was performed with prior disimpaction. The laxative dose for maintenance was determined on the basis of the defecation diary and clinical chart. The Shapiro-Wilk test and Pearson's and Spearman's correlations were used for statistical analysis. Results: The overall group median value and interquartile range of the CTT test was 43.8 (31.8) hours. The average PEG 4000 dose for maintenance in the overall group was $0.68{\pm}0.18g/kg/d$; according to age, the dose was $0.73{\pm}0.16g/kg/d$ (<8 years), $0.53{\pm}0.12g/kg/d$ (8 to <12 years), and $0.36{\pm}0.05g/kg/d$ (12 to 15 years). The dose of lactulose was $1.99{\pm}0.43mL/kg/d$ (<8 years) or $1.26{\pm}0.25mL/kg/d$ (8 to <12 years). There was no significant correlation between CTT test value and initial dose of laxative, irrespective of the subgroup (encopresis, abnormal CTT test subtype) for either laxative. Even in the largest group (overall, n=109, younger than 8 years and on PEG 4000), the correlation was weak (Pearson's correlation coefficient [R]=0.268, p=0.005). Within the abnormal transit group, subgroup (n=73, younger than 8 years and on PEG 4000) correlation was weak (R=0.267, p=0.022). Conclusion: CTT test value cannot predict the initial maintenance dose of PEG 4000 or lactulose with linear correlation.