• Journal of the Korean Society of Physical Medicine
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• v.15 no.1
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• pp.55-63
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• 2020

PURPOSE: This study examined the effects of handgrip exercise, which was started two weeks after surgery for shoulder rotator cuff repair, on the extent of muscle activation around the shoulder and the cross-sectional area of the supraspinatus muscle. METHODS: Among patients diagnosed with rotator cuff rupture by an orthopedic surgeon and rotator cuff repair was performed using an arthroscope, 28 were selected as subjects. These subjects were allocated randomly to the experimental group and control group with 14 subjects in each group. An electromyogram was measured as a measure of the extent of muscle activation around the shoulder for a total of six times (%RVC). The cross-sectional area of the supraspinatus muscle was measured before and after the rotator cuff repair by magnetic resonance imaging. RESULTS: The extent of muscle activation in accordance with time in both the experimental group and control group displayed significant differences in various muscles including the anterior deltoid, pectoralis major, upper trapezius and infraspinatus muscle(p<.05). A significant difference in the variation of the cross-sectional area of the supraspinatus muscle was observed between the experimental group and the control group(p<.05). CONCLUSION: Handgrip exercise helps rehabilitate the shoulder joint at the acute stage after rotator cuff repair when assertive exercise therapy cannot be applied.

• The Journal of Korean Physical Therapy
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• v.25 no.5
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• pp.316-321
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• 2013

Purpose: The aimed of this study was to investigate muscle activation related to postural stability according to different frequency of whole body vibration during quiet standing, to identify the most effective training conditions that cause the highest neuromuscular responses, and to evaluate the difference of EMG activation according to the anatomical position of the muscle - proximal or distal from the vibration platform. Methods: Eighteen healthy subjects voluntarily participated in this single-group, repeated-measures study in which EMG data from upper trapezius, rectus abdominalis, external oblique abdominalis, elector spinae, gluteus maximus, rectus femoris, semitendinosus, and gastrocnemius were collected over different frequencies (0-5-10-15-20-25Hz) for each subject during quiet standing. Results: We observed a statistically significant difference in the mean values of %RVC of muscular activation according to different frequencies of whole body vibration during quiet standing in all muscles (p<0.05). Conclusion: Our results indicate that lower frequencies of vibration result in low muscular activation, and higher frequencies elicit high muscular activation. However, the most effective training condition that caused the highest activation was 20 Hz. In addition, the proximally located lower extremity muscles (GCM, RF, ST, GM) showed higher activation than the distally located trunk and neck muscles (ES, EO, RA, UT) together with increasing frequency.

• Physical Therapy Korea
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• v.17 no.4
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• pp.26-34
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• 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.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.295-298
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• 2003

Reflective mode liquid crystal on silicon (LCoS) microdisplay is the major technology that can produce extremely high-resolution displays. A very large number of pixels can be packed onto the CMOS circuit with integrated drivers that can be projected to any size screen. Large size direct-view thin film transistor (TFT) LCDs becomes very difficult to make and to drive as the information content increases. However, the existing LC alignment technology for the LCoS cell fabrication is still the mechanical rubbing method, which is prone to have minor defects that are not visible normally but can be detrimental if projected to a large screen. In this paper, application of photo-alignment to LCoS fabrication is presented. The alignment is done by three-step exposure process. A MTN $90^{\circ}$ mode is chose as to evaluate the performance of this technique. The comparison with rubbing mode shows the performance of photo-alignment is comparable and even better in some aspect, such as sharper RVC curve and higher contrast ratio.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.20 no.1
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• pp.39-45
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• 2014

Background: The purpose of this study is to identify effects of neuro-muscular control training on vastus medialis oblique (VMO) after menisectomy of the knee. Methods: The subjects of this study are women aged 42 and 39 each who did menisectomy. Case 1 was applied quadriceps setting exercise and neuro-muscular contrlol training and case 2 was applied quadriecps setting. Intervention was done 5 times a week for 2 weeks. Measurement of muscle activity on VMO and vastus lateralis (VL) was standardized signals of each muscle to %RVC using surface EMG. Results: On comparison of exercise before and after on VMO and VL, VL activation of case 2 was increased more than case 1. Conclusion: Quadriecps-setting exercise and selective neuro-muscular control training of VMO is effective intervention on VMO activity and muscle activity ratio of VMO to VL.

• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.630-632
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• 1998

The basic user location strategies proposed in current PCS(Personal Communication Services) Network are two-level Database strategies. These Databases which exist in the Signalling network always maintain user's current location information, and it is used in call setup process to a mobile user. As the number of PCS users are increasing, this strategies yield some problem such as concentrating signalling traffic on the Database, increasing Call setup Delay, and so on. In this paper, we proposed RCP(Reverse Connection setup Protocol) model, which apply RVC(Reverse Virtual Call setup) algorithm to PCS reference model, and CRCP(Cache algorithm in RCP) model, which adopt Caching strategies in the RCP model. When Cache-miss occur, we found that CRCP model require less miss-penalty than PCS model. Also we show that proposed models are always likely to yield better performance in terms of reduced Location Tracking Delay time.

• Journal of International Academy of Physical Therapy Research
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• v.11 no.2
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• pp.2065-2070
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• 2020

Background: Weakness of the abdominal and mid thoracic muscles the lead to thoracic kyphosis of stroke patients. The trunk muscles activity of stroke patients is significantly related to upper extremity. Objectives: To investigate the effect of seated exercise of thoracic and abdominal muscles on upper extremity function and trunk muscles activity in stroke patients. Design: One-group pretest-posttest design. Methods: A total of 27 stroke patients were recruited. All stroke patient were given seated abdominal exercise (posterior pelvic tilt exercises) and thoracic exercise (postural-correction exercise). All exercises were conducted for 30 minutes, three times a week for four weeks. The manual function test (MFT) and electromyography (EMG) were measured, and EMG electrodes were attached to thoracic paraspinal muscles and lower rectus abdominal muscles. EMG signal is expressed as %RVC (reference voluntary contraction). Results: Experimental group showed significant increases in abdominal muscles, paraspinal muscles activity and MFT total score, items of arm motion (forward elevation of the upper extremity, lateral elevation of the upper extremity, touch the occiput with the palm) in MFT after four weeks. Conclusion: These results suggest that, in stroke patients, seated exercise of thoracic and abdominal muscles contribute to improve trunk muscles activity and upper extremity function in stroke patients.

• Journal of Digital Convergence
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• v.10 no.7
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• pp.161-166
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• 2012

When a car accident happened on a highway, the accident vehicle should broadcast a safe message to its neighbors in order to prevent a chain-reaction collision. Also, there is a problem that the estimation accuracy is low because of the memory limit from increasing the sampling count. In this paper, we proposes a HVC systems using a back-off algorithm applied to a gaussian model. And we proposes a MAC protocol preventing the communication delay by separating the neighbor count collection channel, data channel, and RSU communication channel. As a result, we show the frame reception success rate of our protocol improved about 10% than the previous protocol.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.11 no.1
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• pp.7-12
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• 2013

Purpose : The purpose of this study was to identify effects of virtual reality-based closed kinetic chain (CKC) exercise on lower extremity muscle activity in chronic stroke patients Methods : Subjects were assigned randomly either to VR+CKC exercise group (n=15) or the CKC exercise group (n=15). When the study began, both groups received conventional physical therapy five times per week. The VR+CKC exercise group received virtual reality programs and the CKC exercise group received close kinetic chain exercises. Each exercise program was performed for six weeks (5 times per weeks; 20 minutes per time). Participants were measured on lower extremity muscle activity using EMG. Results : There was a significant increase of muscle activity (%RVC) in vastus lateralis and vastus medialis. Conclusion : In this study, the virtual reality-based closed kinetic chain exercise program was an effective exercise for improving lower extremity muscle activity in chronic stroke patients.

• Physical Therapy Korea
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• v.18 no.4
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• pp.51-59
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• 2011

The purpose of this study was to investigate the effect of attentional focus and distance of external focus on the performance of balance task of upper extremity. Subjects (N=30) held a stick (2 m) and maintained it horizontally. All of the subjects performed balance task of upper extremity under four different attentional focus conditions: focus on hand (internal focus), marker at 10 cm inside of hand (external focus 1), marker at 10 cm outside of hand (external focus 2), marker at 20 cm outside of hand (external focus 3). The mean velocity of the bar (mm/s) and the muscle activity of biceps brachii (%RVC) were measured. They were decreased when the subjects focused on external focuses compared to internal focus and decreased as distance of attentional focus from body increased (p<.05). There were significant differences between groups (p<.05); internal focus-external focus 1, internal focus-external focus 2, internal focus-external focus 3, external focus 2-external focus 3. These results showed that external focus is more effective than internal focus in enhancing motor performance and focusing on more distant attentional focus results in enhanced motor performance promoting the utilization of more automatic control mechanisms.