• Title/Summary/Keyword: Group velocity

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Effect of Treadmill Training on Walking Velocity and Gait Endurance in patients with chronic hemiplegia (트레드밀 보행훈련이 만성편마비 환자의 보행 속도와 보행 지구력에 미치는 영향)

  • Kim Sang-Yub
    • The Journal of Korean Physical Therapy
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    • v.16 no.2
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    • pp.44-53
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    • 2004
  • Treadmill training is a new promising therapy in gait rehabilitation of patients with hemiplegia. The purpose of this study was to identify the effect of treadmill training on walking speed and gait endurance in patients with chronic hemiplegia. The subject of this includes twenty patients, who had suffered from chronic hemiplegia and were in the K rehabilitation center; each ten patients were randomly assigned to experimental or control group. Among twenty patients, one group of ten for experiment was treated with progressive speed increase treadmill ambulation traing besides conventional physical therapy(SITAT) while the rest ten for the controlled group was treated with conventional physical therapy(CPT) only, for 8 weeks alike. Before and after the foregoing 8 weeks training, walking velocity and gait endurance were measured to both groups. The data were analyzed by paired t-test. The results of this study are as follows; The SITAT and CPT showed the significant difference in walking velocity and gait endurance. As compared the rehabilitation of dependent varibles between the SITAT and CPT, SITAT showed the significant difference in walking velocity and gait endurance. The outcome suggest that patient with chronic hemiplegia can improve their walking velocity and gait endurance throught treadmill training.

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The Effect of Closed Kinetic Chain Exercise with FES of the Gluteus Medius on Gait in Stroke (닫힌 사슬운동과 병행된 중간볼기근의 기능적 전기자극이 편마비환자의 보행에 미치는 효과)

  • Lee, Su-Kyoung;Park, Min-Chull;Shim, Je-Myung;Kim, Kyung
    • Journal of the Korean Society of Physical Medicine
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    • v.6 no.1
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    • pp.1-8
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    • 2011
  • Purpose : The purpose of this study was to find out the effect of closed kinetic chain exercise with functional electrical stimulation(FES) of the gluteus medius on gait in stroke. Methods : 30 hemiplegic patients voluntarily participated in this study. Subjects were divided into experimental group(n=15) and control group(n=15). Experimental group was given closed kinetic chain exercise with FES of the gluteus medius and control group was given only closed kinetic chain exercise for 4 weeks. All subjects were measured 10m-walking speed, cadence, functional walking category(FAC) and modified motor assessment scale(MMAS) before and after intervention. Results : In experimental group, gait velocity, cadence, FAC and MMAS showed significant difference between pre and post test(p<.05). In control group, gait velocity, cadence and FAC showed significant difference between pre and post test(p<.05). Before intervention, gait velocity, cadence, FAC and MMAS were not significant difference between experimental group and control group(p>.05), but after intervention, gait velocity, FAC and MMAS were significant difference(p<.05). Conclusion : This study show that closed kinetic chain exercise with functional electrical stimulation(FES) of the gluteus medius is beneficial intervention for increase the wlking ability in stroke.

The Effect of Hip Abductor Strengthening Exercise using Elastic Band on Static Balance (탄력밴드를 이용한 고관절 외전근 근력강화운동이 정적 균형에 미치는 영향)

  • Kim, Yoon-Hwan;Park, Jong-Hang;Choi, Won-Jye;Kim, Young-Mi;Kim, Tae-Won;Lee, Moon-Kyu
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.15 no.1
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    • pp.49-57
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    • 2009
  • Purpose : To evaluate the effects hip abductor strengthening exercise using elastic band on static balance. Methods : The subjects consisted of twenty healthy people. The subjects were divided into two group. The control group(n=10) received no exercise and/or stimulation. The elastic band strengthening exercise(E/E) group(n=10) performed hip abductor for strengthening exercise using elastic band. E/E group were accomplished during 6weeks(3day/week, 30-40min/day). All tests were completed before and after experiment. The static balance ability was measured by normal standing when eye open and close on GOOD BALANCE System, respectively. For each case, the experimental data were obtained in 3 items: mean X speed, mean Y speed and velocity moment. Results : The results of this study were as follows; 1. In E/E group, the statistically significants were shown on Y speed and velocity moment in the case of normal standing when eye open and X speed and velocity moment in the case of normal standing when eye close(p<0.05). 2. In control group, the statistically significants were not shown on all posture(p>0.05). 3. There was a statistically significant difference on the X speed and velocity moment in the case of normal standing when eye close between control group and E/E group(p<0.05). Conclusion : The above results revealed that hip abductor strengthening exercise using elastic band were partly effective for improving the static balance ability.

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AN IN-SITU YOUNG'S MODULUS MEASUREMENT TECHNIQUE FOR NUCLEAR POWER PLANTS USING TIME-FREQUENCY ANALYSIS

  • Choi, Young-Chul;Yoon, Doo-Byung;Park, Jin-Ho;Kwon, Hyun-Sang
    • Nuclear Engineering and Technology
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    • v.41 no.3
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    • pp.327-334
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    • 2009
  • Elastic wave is one of the most useful tools for non-destructive tests in nuclear power plants. Since the elastic properties are indispensable for analyzing the behaviors of elastic waves, they should be predetermined within an acceptable accuracy. Nuclear power plants are exposed to harsh environmental conditions and hence the structures are degraded. It means that the Young's modulus becomes unreliable and in-situ measurement of Young's modulus is required from an engineering point of view. Young's modulus is estimated from the group velocity of propagating waves. Because the flexural wave of a plate is inherently dispersive, the group velocity is not clearly evaluated in temporal signal analysis. In order to overcome such ambiguity in estimation of group velocity, Wigner-Ville distribution as the time-frequency analysis technique was proposed and utilized. To verify the proposed method, experiments for steel and acryl plates were performed with accelerometers. The results show good estimation of the Young's modulus of two plates.

The Correlation between Power Error and Velocity Error according to the Condition and Frequency of Self-Controlled Feedback during Knee Extension

  • Yoon, Jung Gyu
    • Journal of International Academy of Physical Therapy Research
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    • v.9 no.4
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    • pp.1602-1607
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    • 2018
  • This study examined the correlation between power error (PE) and velocity error (VE) according to the condition and frequency of self-controlled feedback (SCF) during knee extension. One hundred participants were randomly assigned to 30% SCF, 70% SCF, 30% yoked feedback (YF), 70% YF and control group, respectively. The SCF group was provided with feedback when they requested it, whereas the YF group did not influence the feedback schedule. Participants in the control group were not given any visual feedback during the experiment. The isotonic, isometric, and isokinetic dynamometer (PRIMUS RS, BTE, USA) was used to measure the power and velocity error during knee extension. The collected data was analyzed using a Pearson test and SPSS 21.0. The correlation between PE and VE according to the condition and frequency of feedback on each phase during knee extension was significant. Both PE and VE were significantly higher when the feedback was provided with high frequency, passive, and no feedback. Our study suggests that application of SCF can help to improve the proprioception of the healthy person while reducing errors through low frequency and active feedback.

Kinematical Analysis of the Back Somersault in Floor Exercise (마루운동 제자리 뒤공중돌기 동작의 운동학적 분석)

  • Chung, Nam-Ju
    • Korean Journal of Applied Biomechanics
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    • v.17 no.2
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    • pp.157-166
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    • 2007
  • This study was to compare the major kinematic factors between the success and failure group on performing the back somersault motion in floor exercise. Three gymnasts(height : $167.3{\pm}2.88cm$, age : $22.0{\pm}1.0years$, body weight : $64.4{\pm}2.3kg$) were participated in this study. The kinematic data was recorded at 60Hz with four digital video camera. Two successful motions and failure motions for each subject were selected for three dimensional analysis. 1. Success Trail It was appear that success trail was larger than failure group in projection velocity, but success trail was smaller than failure trail in projection angle. Also it was appear that success trail was longer than failure group in the time required. Hand segment velocity and maximum velocity in success trail were larger than those in failure trail, and this result was increasing the projection velocity and finally increasing the vertical height of center of mass. At the take-off(event 2), flection amount of hip and knee joint angle was contributed to the optimal condition for the take-off and at the peak point, hip and knee joint angle was maximum flexed for reducing the moment of inertia. Also in this point, upper extremities of success trail extended more than those of failure trail. in this base, success trail in upward phase(p3) 2. Failure Trail It was appear that failure trail was smaller than success trail in projection velocity, but failure trail was larger than success trail in projection angle. Also it was appear that failure trail was more short than success trail in the time required. Hand segment velocity and maximum velocity in failure trail were smaller than those in success trail, and this result was reducing the projection velocity and finally reducing the vertical high of center of mass. At the take-off(event 2), flection amount of hip and knee joint angle wasn't contributed to the optimal condition for the take-off and at the peak point, hip and knee joint angle wasn't maximum flexed for reducing the moment of inertia. Also in this point, upper extremities of failure trail didn't extended more than those of success trail.

The S-wave Velocity Structure of Shallow Subsurface Obtained by Continuous Wavelet Transform of Short Period Rayleigh Waves (Continuous Wavelet Transform을 단주기 레일리파에 적용하여 구한 천부지반 S파 속도구조)

  • Jung, Hee-Ok;Lee, Bo-Ra
    • Journal of the Korean earth science society
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    • v.28 no.7
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    • pp.903-913
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    • 2007
  • In this study, the researchers compared the S-wave velocity structures obtained by two kinds of dispersion curves: phase and group dispersions from a tidal flat located in the SW coast of the Korean peninsula. The ${\tau}-p$ stacking method was used for the phase velocity and two different methods (multiple filtering technique: MFT and continuous wavelet transform: CWT) for the phase velocity. It was difficult to separate higher modes from the fundamental mode phase velocities using the ${\tau}-p$ method, whereas the separation of different modes of group velocity were easily achieved by both MFT and CWT. Of the two methods, CWT was found to be more efficient than MFT. The spatial resolutions for the inversion results of the fundamental mode for both phase and group velocities were good for only a very shallow depth of ${\sim}1.5m$. On the other hand, the spatial resolutions were good up to ${\sim}4m$ when both the fundamental and the 1st higher mode poop velocities obtained by CWT were used for S-wave inversion. This implies that the 1st higher mode Rayleigh waves contain more information on the S-wave velocity in deeper subsurface. The researchers applied the CWT method to obtain the fundamental and the 1st higher mode poop velocities of the S-wave velocity structure of a tidal flat located in SW coast of the Korean peninsula. Thea the S-wave velocity structures were compared with the borehole description of the study area.

The Kinematic Analysis of Back-Kick Motion in Taekwondo (태권도 숙련자와 미숙련자의 공격뒤차기 동작에 대한 운동학적 분석)

  • Lee, Dong-Jin;Park, Chan-Ho;Kim, Hun-Soo
    • Korean Journal of Applied Biomechanics
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    • v.16 no.3
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    • pp.43-51
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    • 2006
  • The purpose of this study was to analyze kinematic variables during turing back kick motion of Taekwondo. The subjects of this study were the 4 skilled and 4 unskilled of male university player in respectively. The experiment of this study was used two 16mm high speed cameras and its speed 125 frames/s. Analysis of this data was three dimensional cinematography using KWON3D program package. The results were as following; 1. In the elapsed time, there was no significance difference statically between a skilled and unskilled group. But skilled group was more fast during the motion of I phase. And unskilled group was more fast during the motion of II phase so called force production section, which had an influence on Diechagi's velocity. 2. In the center of gravity of human body, the changing of it was $1.10{\pm}0.04m$, $1.12{\pm}0.03m$ of LFM(left foot movement) and $1.36{\pm}0.08m$, $1.39{\pm}0.09m$ of RKF(right knee flection), and $1.44{\pm}0.08m$, $1.42{\pm}0.09m$ of RFI(right foot impact). There was no significance difference statically between the two groups. 3. The velocity of heel on impact was 1.13m/s in the skilled group and 1.23m/s in the unskilled group, when each angle of knee was $110.4{\pm}10.9deg/s$, $114.8{\pm}28.4deg/s$. The maximum velocity of each performance was reached before the RKF, and the velocity and angle at impact along by two groups did not show any significant difference statically. 4. In the angular velocity of just RKF of lower leg, there was significance difference statically between the two groups(p<.05).

The Kinematic Analysis of Kasamatus in Vault (도마종목의 Kasamatsu 기술동작 분석)

  • Lee, Soon-Ho;Back, Jin-Ho;Kim, Young-Sun;Kong, Tae-Ung
    • Korean Journal of Applied Biomechanics
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    • v.15 no.4
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    • pp.1-11
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    • 2005
  • The study were to assess technical factors between the high score group and the low score group, from the subjects of 8 male national gymnasts, and to analyze the kinematical characteristic and main technical cause on technique of Kasamatsu movement on Vault. The result of this study is this. In case of horse contact time the high score group was swifter than low score group, and there was significant difference between the high score group and the low score group(<.01). On high score group the time of taking on from horse showed shorter than that of taking off from horse, while of the low score group the time of taking on the horse was similar to that of taking off from horse on the average. And in time of pre-flight the high score group on average the was 0.16sec shorter times than the low score group, and so there was significantly difference between groups(<.05). Also It is a characteristic that the high score group was short in horse contact time and longer in post-flight. In the horizontal distance of post-flight, the high score group was 0.11m longer than the low score group and there was significantly statistic difference between groups(<.05). In the vertical height of the cog in Post-flight's phrase, the high score group was 0.15m higher than the low score group and there was significantly statistic difference between groups(.<01). The horizontal velocity and vertical velocity in the event of taking on and off Beat board and Vault weren't significantly statistic differences between two groups. In the slow-down of average horizontal velocity during keeping contact with the beat board, the high score group was larger than the low score group. And in an increased average vertical velocity during keeping contact with the beat board, the high score group was even larger than the low score group. In the projectile angle of cog in taking off the beat board, 40.2deg., the angle of low score group and 39.5deg., the angle of high score group are nearly alike. In the projectile angle of cog in taking off the beat, the high score group showed 1.6Wt larger on average than the low score group. However the average reaction force on the board and Vault wasn't almost different between two groups, showed 0.3~0.6Wt larger in the high score group.

A NOTE ON THE DISPERSION RELATION OF THE MODIFIED BOUSSINSQ EQUATIONS

  • Cho, Yong-Sik;Lee, Chang-hoon
    • Water Engineering Research
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    • v.1 no.4
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    • pp.293-298
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    • 2000
  • Optimal values of $\alpha$ characterizing the linear dispersion property in the modified Boussinesq equations are determined by minimizing the combined relative errors of the phase and group velocities. The value of $\alpha$ is fixed in previous studies, whereas it is varying in the present study. The phase and group velocities are calculated by using variable $\alpha$ and compared to those of the linear Stokes wave theory and previous studies. It is found that the present study produces the best match to the linear Stokes theory.

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