• 생명과학회지
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• 제20권11호
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• pp.1704-1710
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• 2010

본 연구는 뇌졸중 발병 후 재활운동에 참가하는 환자들을 대상으로 재활운동 3개월이 지난 시점에서 1차 실험을 하였고, 6개월이 지난 시점에서 2차 실험을 하여 운동역학적 비교분석을 하였다. 실험에 사용된 장비는 영상분석기, 족저압분석기, 근전도분석기를 사용하였다. 대상자는 7명으로 하였으며 통계방법은 t-test분석 이용하였다. 결과는 엉덩관절의 최대신전 피크 값과 최대신전 피크 모멘트 값에서 통계적으로 유의한 차이를 나타내었다(p<0.05). 족저압의 비교에서는 환측 다리의 족저압에서 일반적인 걷기 동작시에 족저압의 중심이동거리에서 통계적으로 유의한 차이를 나타내었다(p<0.05). 근전도 분석에서는 대퇴사두근 중의 대퇴직근과 외측광근의 근력에서 통계적으로 유의한 차이를 나타내었다(p<0.05).

• The Journal of Korean Physical Therapy
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• 제25권3호
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• pp.136-142
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• 2013

Purpose: The application of transcutaneous electrical nerve stimulation (TENS) is beneficial for joint movements, inhibition of spasticity, and the improvement of walking ability in patients with chronic hemiplegia. This study aimed to identify the effect of the application of TENS to the knee extensor on the affected side with respect to postural-sway distance and velocity during the sit-to stand movement. Methods: We included 19 patients with post-stroke hemiplegia in this study. They underwent measurements during the sit-to stand movement on a force plate with 5 different stimulation dosages applied over 7 s:No TENS, high-frequency and high intensity TENS, high-frequency and low intensity TENS, low-frequency and high intensity TENS, and low-frequency and low intensity TENS The 5 different condition were administered in random order. Results: The group that received TENS application exhibited a significant decrease in path length and average velocity of center of pressure (COP) displacement compared with the group that did not receive TENS application. TENS dosage at low frequency (3Hz) and high intensity yielded a significant decrease in path length, average velocity, mediolateral distance and anteroposterior distance of COP displacement (p<0.05). Conclusion: Our results demonstrated the effectiveness of the application of low-frequency TENS on STS performance. These findings provide useful information on the application of TENS for the reduction of postural sway during the sit-to-stand movement after stroke.

• The Journal of Korean Physical Therapy
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• 제28권5호
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• pp.274-278
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• 2016

Purpose: This study investigated changes in static balance during eye movement while in an upright standing position and compared static balance in elderly individuals according to age. Methods: A total of 154 elderly persons (male 23, female 136) were enrolled in the study. Participants followed an eye movement program that consisted of randomly occurring pursuit eye movement and saccadic eye movement. Participants were asked to remain in the double-leg standing position for 2 minutes 30 second while fixating their eyes on a specific target, after which they were instructed to perform eye movements for 2 minutes and 30 seconds. Static balance was measured in terms of the area, length, and average speed (cm/s) of the center of pressure (COP) displacement before and after eye movement intervention with the eyes open. Results: The area, length, and velocity of COP displacement improved significantly (p< 0.01) after intervention. No significant differences among age groups were observed. Conclusion: The results indicated that eye movement was an effective intervention for improving static balance in elderly persons.

• 설비공학논문집
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• 제24권2호
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• pp.147-154
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• 2012

Recently, many researchers have studied the performance of the transcritical $CO_2$ refrigeration cycle in order to improve the system efficiency. In this study, the length of IHX in the $CO_2$ ejector cycle was varied so as to evaluate the performance improvement. As a result, compressor work and cooling capacity was increased by 3% and 5% as the length of internal heat exchanger was changed from 3 m to 15 m. The best COP was appeared at internal heat exchanger length of 12 m, and it was 3.01. Besides, the length of internal heat exchanger has a big effect to pressure lift ratio and entrainment ratio in the ejector $CO_2$ cycle and it may be changed with operating conditions and system specifications.

• Physical Therapy Rehabilitation Science
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• 제9권1호
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• pp.10-17
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• 2020

Objective: Hallux valgus (HV) is a common musculoskeletal deformity that is accompanied with pain and continues to decrease one's quality of life and ability to perform daily life activities by affecting gait and static stability. Therefore, this study aimed to investigate the effect of the angle of HV (HVA) and to compare the one-legged stance and gait parameters in young adults with less HV and severe HV. Design: Cross-sectional study. Methods: Forty young adults were divided into two groups, where HVA ≥15° (n=20) was defined as HV, and HVA <15° (n=20) was defined as normal. For balance ability, the center of pressure (COP) path, velocity, length of axis of the COP path, deviation of the x-axis and y-axis, and percentage of foot pressure were measured, and gait, the foot rotation angle, step length, percentage of each phase of the gait cycle, time change from the heel to forefoot, and maximum pressure of the forefoot and midfoot were measured. Results: Significant differences were found in sway length and time change from heel to forefoot during walking between the normal and HV groups (p<0.05). Most parameters were not associated with the HVA, but parameters such as length of axis and time to change from heel to forefoot were significantly associated with the HVA (p<0.05). Conclusions: These results suggest that most one-legged stance and gait parameters were not significantly affected by the HVA in young adults; therefore, future studies are needed in order to address other dynamic parameters and other methods of gait analysis for detecting clinically meaningful conditions.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.550-555
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• 2009

The present simulation focuses on the effect of the shape of capillary tube-suction line heat exchangers(SLHX), The results in the three cases of the SLHX types show that both of the location and length of heat exchange section influence the coefficient of performance(COP) and cooling capacity. Simulation shows the COP may be improved by 4.6% and the cooling capacity may be improved by 13.6% in the Lateral type.

• 설비공학논문집
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• 제8권2호
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• pp.208-218
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• 1996

Performance of a VM heat pump is considerably affected by various losses, such as enthalpy dump, reheat loss, pumping loss, conduction loss and shuttle loss. A second-order analysis model of VM heat pumps, which allows consideration of the major losses, was presented. Actual heat transfer rates for heat exchangers were calculated from the heat transfer rates obtained by the adiabatic analysis and various losses. New effective temperatures of heat exchangers were calculated from the actual heat transfer rates and the mean heat transfer coefficients until there was no appreciable change in the effective temperatures. Effects of design parameters, such as phase angle, swept volume ratio, regenerator length and speed on heating capacity, cooling capacity and COP were shown.

• 설비공학논문집
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• 제7권3호
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• pp.501-511
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• 1995

A numerical model for predicting the performance of gas distrubutor type double inlet pulse tube refrigerators has been developed. The model was based on adiabatic analysis and the losses of heat exchangers and regenerator were considered. Thermodynamic behavior of working fluid within a double inlet pulse tube refrigerator was investigated and the effects of design parameters, such as valve and orifice openings, cold heat exchanger temperature, frequency and pulse tube length, on the cooling capacity and COP were shown.

• 대한정형도수물리치료학회지
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• 제19권1호
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• pp.49-54
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• 2013

Background: The purposed of this study is to examine the static and dynamic plantar foot pressure in chronic low back pain patients and normal adults. Methods: The subjects were divided into a group of 30 patients with chronic low back pain and a control group of 30 healthy persons. While static posture and dynamic posture at comfortable walking speeds, the low back pain group and the control group measured their plantar foot pressure and the trajectory of their center of pressure (COP) using the Matscan(R) system. Independent t-tests were measured to compare differences in plantar foot pressure characteristics between the left side and right side of the low back pain group and the control group. Results: In the comparison of differences in plantar foot pressure characteristics between the left side and right side of the low back pain group and the control group, the anteroposterior (AP) displacement of COP showed significant differences (p<.05). Although the low back pain group and the control group did not show any significant differences in leg length, weight distribution, mediolateral (ML) displacement of COP, static contract area, dynamic contract areas (p>.05), increases in the contract area values were shown in the hind foot in general. Conclusion: In this study, it was shown that patients with chronic low back pain were walking with short AP displacement of the COP as a compensatory action to avoid pain.

• 대한물리의학회지
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• 제17권4호
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• pp.93-101
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• 2022

PURPOSE: This study sought to investigate the effects of treadmill gait training combined with a thoracic mobility exercise on gait and balance in patients with stroke. METHODS: In this single-blinded, randomized, controlled, comparative study, a total of 20 patients at a rehabilitation hospital who had suffered a hemiplegic stroke were randomly assigned to the experimental group (treadmill gait training combined with a thoracic mobility exercise, n = 11) or control group (treadmill gait training without the thoracic mobility exercise, n = 9). All the participants underwent comprehensive rehabilitation therapy (5 × /week for 4 weeks). Additionally, the experimental group underwent 20 min of treadmill gait training combined with 10 min of a thoracic mobility exercise (3 × / week for 4 weeks) and the control group underwent the former but not the latter. Gait and balance were measured before and after the 4-week training. RESULTS: Significant improvements were observed in the 10-m walking test (10 MWT), timed up-and-go (TUG) test, center of pressure (COP) velocity, and COP length in the experimental group (p < .05). This group also showed a larger decrease in the 10 MWT and COP velocity than the control group (10 MWT, -3.02 sec vs. -1.68 sec, p < .05; COP velocity, -.07 mm/sec vs. .08 mm/sec, p < .05). CONCLUSION: Treadmill gait training, combined with the thoracic mobility exercise, could be effective in improving the gait and balance of stroke patients. It could also be more effective in improving walking speed and static balance than the treadmill gait training alone.