• Physical Therapy Korea
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• v.28 no.1
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• pp.65-71
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• 2021

Background: The hamstring is a muscle that crosses two joints, that is the hip and knee, and its flexibility is an important indicator of physical health in its role in many activities of daily living such as sitting, walking, and running. Limited range of motion (ROM) due to hamstring tightness is strongly related to back pain and malfunction of the hip joint. High-frequency diathermy (HFD) therapy is known to be effective in relaxing the muscle and increasing ROM. Objects: To investigate the effects of HFD on active knee extension ROM and hamstring tone and stiffness in participants with hamstring tightness. Methods: Twenty-four participants with hamstring tightness were recruited, and the operational definition of hamstring tightness in this study was active knee extension ROM of below 160° at 90° hip flexion in the supine position. HFD was applied to the hamstring for 15 minutes using the WINBACK device. All participants were examined before and after the intervention, and the results were analyzed using a paired t-test. The outcome measures included knee extension ROM, the viscoelastic property of the hamstring, and peak torque for passive knee extension. Results: The active knee extension ROM significantly increased from 138.8° ± 9.9° (mean ± standard deviation) to 143.9° ± 10.4° after the intervention (p < 0.05), while viscoelastic property of the hamstring significantly decreased (p < 0.05). Also, the peak torque for knee extension significantly decreased (p < 0.05). Conclusion: Application of HFD for 15 minutes to tight hamstrings immediately improves the active ROM and reduces the tone, stiffness, and elasticity of the muscle. However, further experiments are required to examine the long-term effects of HFD on hamstring tightness including pain reduction, postural improvement around the pelvis and lower extremities, and enhanced functional movement.

• Journal of the Korean Society of Physical Medicine
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• v.17 no.1
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• pp.109-116
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• 2022

PURPOSE: This study compared the effect of performing gastrocnemius stretching with and without the self-myofascial release of the sole on the active and passive ankle dorsiflexion angles and muscle tone of the gastrocnemius muscle in subjects with short gastrocnemius muscle. METHOD: A total of 23 subjects with short gastrocnemius muscles were included in this study. The study participants were divided into two experimental groups. Group A performed gastrocnemius muscle self-stretching exercises only, while group B performed self-myofascial release of the sole using a massage ball after the gastrocnemius muscle self-stretching exercises. For both groups, the active and passive ankle dorsiflexion angles were measured using a goniometer, and the tone of the gastrocnemius muscle was assessed using the MyotonPRO®. RESULTS: Within-group comparison showed that the participants in both groups A and B had significantly increased active and passive ankle dorsiflexion angles and decreased gastrocnemius muscle tone (p < .05) after performing their respective exercises. However, no significant differences in the said criteria were observed between groups A and B (p>.05). CONCLUSION: The results of this study showed that both methods were effective in increasing active and passive dorsiflexion angles and decreasing muscle tone. Thus, it is recommended to tailor gastrocnemius stretching exercises according to the patient's condition. If the patient does not experience discomfort in the plantar fasciae, it is recommended to perform the gastrocnemius stretching exercise only without myofascial release and use a massage ball afterward.

• Journal of the Korea Society for Simulation
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• v.18 no.2
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• pp.77-89
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• 2009

Visual tracking technique is one of the essential things which are very important in the major fields of modern society. While contour tracking is especially necessary technique in the aspect of its fast performance with target's external contour information, it sometimes fails to track target motion because it is affected by the surrounding edges around target and weak egdes on the target boundary. To overcome these weak points, in this research it is suggested that PDMs can be obtained by generating the virtual 6-DOF motions of the mobile robot with a CCD camera and the image tracking system which is robust to the local minima around the target can be configured by constructing Active Shape Model in modular base. To show the effectiveness of the proposed method, the experiment is performed on the image stream obtained by a real mobile robot and the better performance is confirmed by comparing the experimental results with the ones of other major tracking techniques.

• Physical Therapy Korea
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• v.3 no.1
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• pp.32-39
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• 1996

For effective rehabilitation of the shoulder, physical therapists must have correct knowledge of shoulder movements. The purpose of this study was to determine the relationship between shoulder movements and the rotation of the humerus in the sagittal, coronal and scapular planes. Fifty normal subjects(25 male, 25 female) were tested using a Dualar-plus digital goniometer and an air-splint. The subjects performed active shoulder elevation in each plane with the humerus rotated in both medial and lateral directions. The range of motion(ROM) of the glenohumeral joint was measured three times. The paired t-test was used to determine the difference in ROM between medial and lateral rotation of the humerus. Results showed that, in the sagittal and the coronal planes, there was a significant difference(p < 0.01) in ROM of the shoulder between medial rotation and lateral rotation which was greater. But in the scapular plane, there was no difference between medial and lateral rotation. Physical therapists should consider these results when the goal of treatment is to increase ROM of the shoulder.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.68.1-68.1
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• 2015

Gravitational collapse is a dynamical process associated with star formation. One observational evidence of such infall motion is so called "blue asymmetry" profile, which is the optically thick line profile with the intensity peak skewed blueward relative to the intensity peak of optically thin lines. We analyzed both HCN J=1-0 and HNC J=1-0 line profiles to study the inflow motion in different evolutionary stages of massive star formation; Infrared dark clouds (IRDCs), High-mass protostellar object (HMPOs), and Ultra-compact HII regions (UCHIIs). The infall asymmetry in the HCN spectra seems to be more prevalent than the HNC spectra throughout all the three evolutionary phases. The prevalence of the blue profile in the HCN spectra is found in every evolutionary stage, with IRDCs showing the largest blue excess. In the case of the HNC spectra, only IRDCs show the blue excess statistically significant. These results suggest that HCN may be a better infall tracer in massive star forming region. In addition, even though the characteristics of the blue profile largely depend on the suitable combination of optical depth and critical density, our analyses also indicate that IRDCs may have the most active infall process compared to other evolutionary phases.

• Journal of Digital Contents Society
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• v.12 no.4
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• pp.541-550
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• 2011

MotionTypography is crucial to effective emotional communication in digital society. In this paper, I study movements to represent emotion using motiontypography and approach two goals: First to define an emotional measure by means of emotion assesses by the public, Second to research image characteristics corresponding to movements. In this dissertation, we collect emotional words by literature and experimental surveys and extract representative emotional words using KJ method and clustering analysis. The results of research, the emotional axes selected for motiontypography represent 'calm to active' and 'soft to stiff', the viewers feel a specific emotional state from some movements of motiontypography. If, we investigate the relationship of motiontypographic visual elements with emotional words are achieved together, I think it will serve as a motiontypographic guideline that enables helping the public to easily produce motiontypography.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.521-524
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• 2005

In order to measure ECG in daily life, a new ECG measurement method on bed was developed. The provided method does not require any direct conductive contact between the instrument and bare skin, so that it does not cause the uncomfortable feel of touch and the possible skin trouble which are typical shortcomings of the conventional conductive contact ECG measurement. The provided method utilized an array of high-input-impedance active electrodes fixed on the mattress and an indirect-skin-contact ground made of a large conductive textile sheet and laid on lower area of the mattress. A thin cotton bedcover covered the mattress, the electrodes, and the conductive textile and subjects lay on the mattress over the bedcover. ECG was obtained successfully. However its signal quality is lower and the motion artifact is larger than direct-contact measurement. Careful measurement setup was needed to reduce the motion artifact originated from variation in static electricity. From the ECG obtained by the provided method, R-peak could be discriminated easily and the information about the position and the posture of the subject could be obtained.

• Physical Therapy Korea
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• v.21 no.1
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• pp.55-62
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• 2014

For professional drivers, there is a possibility to have musculoskeletal disorders on ankle joint due to repetitive pedaling operation. Therefore, this study have focused to examine ankle active range of motion (AROM), dorsiflexor strength, and pressure pain threshold (PPT) of tibialis anterior muscle (TA) in taxi drivers compared to a age-matched control group. Thirty male taxi drivers with at least 10 years of driving experience and thirty male sedentary workers were evaluated for ankle AROM, dorsiflexor strength, and PPT of TA. Multiple independent t-tests were used to identify significant differences between two groups. For the results, taxi drivers had significantly less AROM in dorsiflexion and greater AROM in external tibial rotation compared to the control group. Also, dorsiflexor strength and PPT of TA in taxi drivers was significantly lower than in the control group. This study indicates that the repetitive ankle movements associated with driving have an effect on ankle AROM, dorsiflexor strength, and PPT of TA and may lead to work-related musculoskeletal disorders on ankle. Professional drivers may need to be educated to prevent a potential musculoskeletal disorders associated with repetitive movement.

• The Journal of the Acoustical Society of Korea
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• v.36 no.2
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• pp.130-135
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• 2017

In this paper, we propose an interface for interactive sound experience in the virtual concert hall. The proposed interface consists of two systems, called 'virtual acoustic position' and 'virtual active listening'. To provide these systems, we applied an artificial reverberation algorithm, multi-channel source separation and head-related transfer function. The proposed interface was implemented by using Unity. The interface provides the virtual concert hall to user through Oculus Rift, one of the virtual reality headsets. Moreover, we used Leap Motion as a control device to allow a user experience the system with free-hand. And user can experience the sound of the system through headphones.

• International Journal of Control, Automation, and Systems
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• v.5 no.5
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• pp.559-569
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• 2007

In this paper, the dynamic controller design problem of a redundant planar 2-dof parallel manipulator is studied. Using the Euler-Lagrange equation, we formulate the dynamic model of the parallel manipulator in the joint space and propose an augmented PD controller with forward dynamic compensation for the parallel manipulator. By formulating the controller in the joint space, we eliminate the complex computation of the Jacobian matrix of joint angles with end-effector coordinate. So with less computation, our controller is easier to implement, and a shorter sampling period can be achieved, which makes the controller more suitable for high-speed motion control. Furthermore, with the combination of static friction model and viscous friction model, the active joint friction of the parallel manipulator is studied and compensated in the controller. Based on the dynamic parameters of the parallel manipulator evaluated by direct measurement and identification, motion control experiments are implemented. With the experiments, the validity of the dynamic model is proved and the performance of the controller is evaluated. Experiment results show that, with forward dynamic compensation, the augmented PD controller can improve the tracking performance of the parallel manipulator over the simple PD controller.