• 제목/요약/키워드: instability of variance

검색결과 27건 처리시간 0.024초

The Effects of Elastic Ankle Taping on Static and Dynamic Postural Control in Individuals With Chronic Ankle Instability

  • Lim, Jin-seok;Kim, Seo-hyun;Moon, Il-young;Yi, Chung-hwi
    • 한국전문물리치료학회지
    • /
    • 제28권3호
    • /
    • pp.200-207
    • /
    • 2021
  • Background: Postural control deficit is a major characteristic in patients with chronic ankle instability (CAI). Elastic ankle tapings are commonly used to facilitate postural control in patients with CAI as well as prevent relapse of a lateral ankle sprain. However, equivocal evidence exists concerning the effect of elastic ankle taping on postural control. Objects: This study aimed to evaluate the effects of elastic ankle tapings using kinesio taping (KT) and dynamic taping (DT) on static and dynamic postural control in patients with CAI. Methods: Fifteen subjects with CAI were participated in this study. The participants performed tests under three conditions (barefoot, KT, and DT). Static postural control was evaluated using the one-leg standing test (OLST) and dynamic postural control using the modified Star Excursion Balance Test (mSEBT). One-way repeated-measures analysis of variance was used to compare center of pressure (CoP) data and normalized mSEBT reach distances among the three conditions (with α = 0.05). Results: The CoP parameters (path length, ellipse area, and mean velocity) of the OLST significantly decreased on applying KT and DT compared with those when barefoot. The normalized reach distances in the anteromedial (AM), medial (M), and posteromedial (PM) directions of the mSEBT significantly increased with DT compared to that in the control condition. Further, the higher reach distances with KT compared with those in the control condition were obtained in the M and PM directions of the mSEBT. No significant differences were identified in any of the OLST and SEBT parameters between the two different taping applications. Conclusion: KT and DT improved static postural control during the OLST compared with the control condition. Moreover, these tapes improved dynamic postural control during the mSEBT compared to the control. Therefore, elastic ankle tapings are useful prophylactic devices for the prevention and treatment of ankle sprain in people with CAI.

A Procedure for Robust Evolutionary Operations

  • Kim, Yongyun B.;Byun, Jai-Hyun;Lim, Sang-Gyu
    • International Journal of Quality Innovation
    • /
    • 제1권1호
    • /
    • pp.89-96
    • /
    • 2000
  • Evolutionary operation (EVOP) is a continuous improvement system which explores a region of process operating conditions by deliberately creating some systematic changes to the process variable levels without jeopardizing the product. It is aimed at securing a satisfactory operating condition in full-scale manufacturing processes, which is generally different from that obtained in laboratory or pilot plant experiments. Information on how to improve the process is generated from a simple experimental design. Traditional EVOP procedures are established on the assumption that the variance of the response variable should be small and stable in the region of the process operation. However, it is often the case that process noises have an influence on the stability of the process. This process instability is due to many factors such as raw materials, ambient temperature, and equipment wear. Therefore, process variables should be optimized continuously not only to meet the target value but also to keep the variance of the response variables as low as possible. We propose a scheme to achieve robust process improvement. As a process performance measure, we adopted the mean square error (MSE) of the replicate response values on a specific operating condition, and used the Kruskal-Wallis test to identify significant differences between the process operating conditions.

  • PDF

S.O.T CATEGORY II BLOCKING이 복근지구력과 어깨 통증에 미치는 영향 (THE EFFECT OF SACROOCCIPITAL TECHNIQUE CATEGORY II BLOCKING ON ABDOMINAL MUSCLE ENDURANCE AND SHOULDER PAIN)

  • 신원선;조일영;김가은;박순권;차경수
    • 디지털융복합연구
    • /
    • 제10권11호
    • /
    • pp.551-558
    • /
    • 2012
  • 본 연구는 카이로프랙틱 기법 중 누운 자세에서 시술되어지는 S.O.T category II 골반 블록 중재가 골반의 불안정으로 인한 기울어짐을 회복시킴으로써 이에 따른 어깨통증을 줄이고 복근의 지구력을 향상시킬 수 있는지 알아보고자 한 것이다. 이 실험을 위해 엉치엉덩관절의 불안정을 가지고 있으며 허리의 통증이 있는 총 50명의 참여자가 실험군과 대조군에 각 25명씩 무작위 할당되었다. 실험군은 category II 블록 중재를 받았고, 대조군은 거짓블록 중재를 받았으며, 이들 두 집단을 통해 중재 전, 중재 후, 그리고 중재 2주 후에 복근지구력과 어깨통증을 측정하여 그 결과를 반복측정 이원분산분석법으로 분석하였다. 분석결과 S.O.T category II 골반 블록 중재 후 실험집단에서 복근지구력이 유의한 증가를 보였으며 중재가 끝난 2주 후에도 유지 되었다. 또한 어깨통증의 경우에도 실험집단에서 통증의 감소를 보였으며 역시 중재가 끝난 2주 후에도 유의한 감소를 보였다. 이상의 연구 결과를 종합해 볼 때 S.O.T category II 골반 블록 중재는 골반의 안정성을 유도하여 복근지구력을 증진시키고, 어깨통증을 감소시키며 중재 후에도 지속효과가 있는 것으로 나타남으로, 골반의 불안정성이 원인이 되는 어깨통증이나 복근지구력을 회복시킬 수 있는 중재법으로 활용되어질 수 있을 것으로 사료된다.

Eletromyographic Activities of Trunk and Lower Extremity Muscles During Bridging Exercise in Whole Body Vibration and Swiss Ball Condition in Elderly Women

  • Kim, Tack-Hoon;Lee, Kang-Seong
    • 한국전문물리치료학회지
    • /
    • 제17권4호
    • /
    • pp.26-34
    • /
    • 2010
  • The purpose of this study was to compare the trunk and lower extremity muscle activity induced by six different conditions floor, intensity 0, 1, 3, 5 of whole body vibration (WBV), and Swiss ball during bridging exercise. Surface electromyography (EMG) was used to measure trunk and lower extremity muscles activity. Ten elderly women were recruited from Hong-sung Senior Citizen Welfare Center. The collected EMG data were normalized using reference contraction (during floor bridging) and expressed as a percentage of reference voluntary contraction (%RVC). To analyze the differences in EMG data, the repeated one-way analysis of variance was used. A Bonferroni's correction was used for multiple comparisons. The study showed that EMG activity of the rectus abdominis, external oblique, internal oblique, erector spinae and rectus abdominis muscles were not significantly different between six different conditions of during bridging exercise (p>.05). However, there were significantly increased EMG activity of the rectus femoris (p=.034) in the WBV intensity 0, 1, 3, and 5 conditions compared with the floor bridging condition. EMG activity of the medial gastrocnemius were significantly increased in the WBV intensity 0, 1, 3, 5 and Swiss ball conditions compared with the floor bridging condition. Future studies are required the dynamic instability condition such as one leg lifting in bridging.

An MHD Simulation of the X2.2 Solar Flare on 2011 February 15

  • Inoue, Satoshi;Choe, Gwangson
    • 천문학회보
    • /
    • 제39권1호
    • /
    • pp.69.1-69.1
    • /
    • 2014
  • We perform an MHD simulation combined with observed vector field data to clarify an eruptive dynamics in the solar flare. We first extrapolate a 3D coronal magnetic field under a Nonlinear Force-Free Field (NLFFF) approximation based on the vector field, and then we perform an MHD simulation where the NLFFF prior to the flare is set as an initial condition. Vector field was obtained by the Soar Dynamics Observatory (SDO) at 00:00 UT on February 15, which is about 90 minutes before the X2.2-class flare. As a result, the MHD simulation successfully shows an eruption of strongly twisted lines whose values are over one-turn twist, which are produced through the tether-cut magnetic reconnection in strongly twisted lines of the NLFFF. Eventually, we found that they exceed a critical height at which the flux tube becomes unstable to the torus instability determining the condition that whether a flux tube might escape from the overlying field lines or not. In addition to these, we found that the distribution of the observed two-ribbon flares is similar to the spatial variance of the footpoints caused by the reconnection of the twisted lines being resided above the polarity inversion line. Furthermore, because the post flare loops obtained from MHD simulation well capture that in EUV image taken by SDO, these results support the reliability of our simulation.

  • PDF

수중초음속제트의 불안정성에 대한 실험적 고찰 (Experimental Observation of Instability of Supersonic Submerged Jets)

  • 정재권;이대훈;차홍석;박승오;권세진
    • 한국추진공학회지
    • /
    • 제6권2호
    • /
    • pp.45-52
    • /
    • 2002
  • 2차원 수중 초음속 제트의 구조 및 유동 불안정성에 대한 실험적 연구를 수행하였다. 제트의 구조 및 시간에 따른 변화를 관찰하기 위하여 고속 디지털 카메라 촬영과 정압을 측정하였다. 공기 유량의 변화에 따른 제트의 구조를 초고속 촬영하여 이로부터 얻어진 장면에서 확산각을 구했다. 일련의 제트의 주기적인 특성에 따른 구조를 관찰하였고 불안정성의 초당 주기 발생 횟수가 5-6회 정도로 측정되었다. 세 가지 특성 길이 $L_1$, $L_2$, $L_3$를 정의하였다. $L_1$은 불안정적 주기가 발생할 경우 최대제트의 폭 스케일, $L_2$는 2차적인 유동이 유입되는 곳의 제트의 폭 스케일, $L_3$는 노즐 출구로부터 2차적으로 유도된 유동이 유임되는 곳까지의 길이다. $L_1$/$L_2$는 전압 즉, 탱크 압력이 증가함에 따라 감소하는 경향성을 가지고 있고 $L_3$는 전압이 증가함에 따라 증가하는 경향성을 띄었다. 시간에 따른 정압 변화를 측정하였으며 FFT결과를 통해서 불안정성으로 인해 발생하는 주파수와 유사한 값인 5Hz에서 고유진동이 발생하는 것을 확인하였다.

자아존중감 및 성인애착이 SNS 중독경향성에 미치는 영향 (The Influence of Self Esteem and Adult Attachment on SNS(Social Network Service) Addiction Tendency)

  • 권예진;김다빈;서보경
    • 한국콘텐츠학회논문지
    • /
    • 제19권1호
    • /
    • pp.47-59
    • /
    • 2019
  • 본 연구는 대학생의 SNS 중독 경향성 실태를 파악하고, 인구통계학적 특성과 자아존중감 및 성인애착 중 불안정 애착(애착불안, 애착 회피)이 SNS 중독경향성과의 관계를 조사하고자 하였다. 대학생의 SNS 중독경향성에 미치는 영향 요인을 파악하기 위해, 수도권 4년제 대학교 재학생 330명을 오프라인과 온라인 질문지를 통하여 조사하였고, 그 중 유효한 271명을 분석하였다. 분석에는 빈도분석, 기술통계분석, 변량분석, Pearson의 상관분석, 다중회귀분석을 실시하였다. 그 결과는 다음과 같다. 첫째, 대학생의 87.4%가 SNS를 사용하고 있었고, 주로 사용하는 SNS는 '페이스북(82.3%)'이었다. 일별 SNS 사용시간은 '1시간 이상~2시간 미만(24.7%)'가 가장 많았다. 둘째, 여성이 남성보다 SNS중독경향성이 유의미하게 높았다. 셋째, 자아존중감과 SNS 중독경향성은 유의미한 부적 상관이 있는 것으로 나타났다. 넷째, 성인애착의 불안정 애착 중에 애착불안와 애착회피는 SNS 중독경향성과 정적 상관을 보였다. 다섯째, 대학생의 자아존중감은 SNS 중독경향성에 부적 영향을 미쳤으며, 불안정 애착 중 애착불안만이 중독경향성에 정적 영향을 미치는 것으로 나타났다. 끝으로, 대학생의 신분적 특성에 따른 SNS 중독 위험성에 대하여 논의하였다.

경증 및 중증 외상성 뇌손상 환자의 성격평가 질문지 프로파일 (Personality Assessment Inventory Profiles of Patients with Mild and Severe Traumatic Brain Injury)

  • 권석준;노승호
    • 생물정신의학
    • /
    • 제12권1호
    • /
    • pp.20-31
    • /
    • 2005
  • Objectives:This study was designed to investigate the characteristics of personality changes and emotional distress using the Personality Assessment Inventory (PAI) in patients with traumatic brain injury(TBI), divided into mild (MTBI) and severe (STBI) groups according to the severity of injury. Methods:The subjects were consisted of 25 patients with MTBI, 25 patients with STBI, and 25 normal controls. They were interviewed with the PAI. The data were analyzed by ${\chi}^2$ test, analysis of variance and Tukey test. Results:The results were the followings. First, Negative Impression in validity scales was elevated above cutoff point(T score 70) in both MTBI and STBI groups. Second, the clinical scales of which scores elevated above the cutoff point were Somatic Complaints, Anxiety, Anxiety-Related Disorders, Depression, and Schizophrenia in the MTBI, and Somatic Complaints and Depression in the STBI. Third, the clinical subscales above the cutoff point were Conversion, Somatization, Health Concerns, Affective Anxiety, Physiological Anxiety, Traumatic Stress, Cognitive Depression, Affective Depression, Physiological Depression, Thought Disorder, and Affective Instability in the MTBI, and Health Concerns, Cognitive Depression, Affective Depression, and Physiological Depression in the STBI. Fourth, Suicide Ideation in treatment scales was the only scale above the cutoff point in the MTBI and the others of the treatment and interpersonal scales in the MTBI and all of these scales of the STBI were not elevated above the cutoff point. Fifth, the scales of which scores showed significant difference between the MTBI and the STBI were Somatic Complaints, Anxiety, Depression, and Suicide Ideation, the subscales were Conversion, Somatization, Health Concerns, Affective Anxiety, Physiological Anxiety, Physiological Depression, and Psychotic Experiences. Conclusion:These results suggest that the patients with MTBI had more somatic and anxiety symptoms, depressed mood, and suicidal ideation than the patients with STBI. These characteristics are generally consistent with clinical observation and findings from previous studies of the patients with TBI, and the PAI seems to be a beneficial adjunctive assessment tool for the evaluation of patients with traumatic brain injury.

  • PDF

Low-noise reconstruction method for coded-aperture gamma camera based on multi-layer perceptron

  • Zhang, Rui;Tang, Xiaobin;Gong, Pin;Wang, Peng;Zhou, Cheng;Zhu, Xiaoxiang;Liang, Dajian;Wang, Zeyu
    • Nuclear Engineering and Technology
    • /
    • 제52권10호
    • /
    • pp.2250-2261
    • /
    • 2020
  • Accurate localization of radioactive materials is crucial in homeland security and radiological emergencies. Coded-aperture gamma camera is an interesting solution for such applications and can be developed into portable real-time imaging devices. However, traditional reconstruction methods cannot effectively deal with signal-independent noise, thereby hindering low-noise real-time imaging. In this study, a novel reconstruction method with excellent noise-suppression capability based on a multi-layer perceptron (MLP) is proposed. A coded-aperture gamma camera based on pixel detector and coded-aperture mask was constructed, and the process of radioactive source imaging was simulated. Results showed that the MLP method performs better in noise suppression than the traditional correlation analysis method. When the Co-57 source with an activity of 1 MBq was at 289 different positions within the field of view which correspond to 289 different pixels in the reconstructed image, the average contrast-to-noise ratio (CNR) obtained by the MLP method was 21.82, whereas that obtained by the correlation analysis method was 5.85. The variance in CNR of the MLP method is larger than that of correlation analysis, which means the MLP method has some instability in certain conditions.

비특이성 만성 경부통 환자에게 적용한 동적 균형 운동이 통증과 기능적 수준, 심리사회적 수준에 미치는 효과 (Effects of Dynamic Balance Exercise on Pain, Functional level, and Psychosocial Level in Patients with Non-specific Chronic Neck Pain)

  • 권유희;김선엽
    • 대한정형도수물리치료학회지
    • /
    • 제29권3호
    • /
    • pp.43-53
    • /
    • 2023
  • Background: Patients with neck pain develop instability due to muscle imbalance, decreased proprioception, and balance disorders. Studies have examined various exercise methods as treatment methods, but few studies have compared the effects of cervical stabilization exercise and dynamic balance exercise. The purpose of this study was to investigate the effects of dynamic balance exercise on pain, functional level, and psychosocial level in patients with non-specific chronic neck pain. Methods: Thirty-four non-specific chronic neck pain patients were randomly assigned to the experimental group (EG, n=17) and control group (CG, n=17); the cervical stabilization exercise and dynamic balance exercise program were applied to the EG; and only the cervical stabilization exercise program was applied to the CG. The intervention was conducted twice a week, for six weeks. Assessment items evaluated pain, dysfunction (Korean version neck disability index), range of motion, craniocervical flexion test, cervical deep flexor endurance test, and psychosocial level. Data analysis was performed using intention-to-treat analysis as assigned. To analyze differences in the items assessed in the two groups, we used a repeated measures analysis of variance with an interaction between group (EG, CG) and time point (baseline, 6 weeks, 12 weeks). Results: The endurance of the cervical flexor muscles between the group and the measurement point after intervention (p<.05). Both groups showed significantly improved endurance between time points after the intervention (p<.05), with the EG showing a greater change than the CG. None of the other measurement items differed in the pattern of change between measurement points. Conclusion: In conclusion, the EG applying a cervical stabilization exercise and a dynamic balance exercise experienced a significant difference in muscle endurance improvement compared to the CG. We propose an exercise intervention program that includes stabilization exercises and dynamic balance exercises for patients with chronic cervical pain who lack muscle endurance.

  • PDF