• Journal of Biomedical Engineering Research
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• v.36 no.5
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• pp.228-234
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• 2015

The balance ability significantly decreased in the elderly because of deterioration of the neural musculature regulatory mechanisms. Several studies have investigated methods of improving balance ability using real-time systems, but it is limited by the expensive test equipment and specialized resources. Recently, Kinect system based on depth data has been applied to address these limitations. Little information about accuracy/inaccuracy of Kinect system is, however, available, particular in motion analysis for evaluation of effectiveness in rehabilitation training. Therefore, the aim of the current study was to evaluate accuracy/inaccuracy of Kinect system in specific rotational movement for balance rehabilitation training. Six healthy male adults with no musculoskeletal disorder were selected to participate in the experiment. Movements of the participants were induced by controlling the base plane of the balance training equipment in directions of AP (anterior-posterior), ML (medial-lateral), right and left diagonal direction. The dynamic motions of the subjects were measured using two Kinect depth sensor systems and a three-dimensional motion capture system with eight infrared cameras for comparative evaluation. The results of the error rate for hip and knee joint alteration of Kinect system comparison with infrared camera based motion capture system occurred smaller values in the ML direction (Hip joint: 10.9~57.3%, Knee joint: 26.0~74.8%). Therefore, the accuracy of Kinect system for measuring balance rehabilitation traning could improve by using adapted algorithm which is based on hip joint movement in medial-lateral direction.

• The Journal of Korean Physical Therapy
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• v.32 no.2
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• pp.88-93
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• 2020

Purpose: This study examined the inter-rater reliability of cervical proprioception, dynamic balance ability, and ankle dorsiflexion range of motion using STARmat^®, which is a practical clinical tool that can provide practitioners and patients with quantitative and qualitative results. Methods: Thirty healthy young subjects were enrolled in this study, and two well-trained physical therapists participated as a tester. Two testers measured the cervical joint position error at the starting position after neck flexion, extension, side bending, and rotation; three dynamic balance tests, including anterior excursion, anterior reaching with single leg balance, and posterior diagonal excursion; and ankle dorsiflexion range of motion using STARmat^®. The intra-class correlation coefficient (ICC) was used to determine the inter-rater reliability of the tests. Results: The inter-rater reliability for the cervical proprioception ranged from moderate to good (0.66 to 0.83), particularly for flexion (0.82), extension (0.70), right side bending (0.73), left side bending (0.71), right rotation (0.83), and left rotation (0.66). For the dynamic balance, the inter-rater reliability ranged from good to excellent (0.87 to 0.91), particularly for anterior excursion (0.86), posterior diagonal excursion (0.87 to 0.89), and anterior reaching with a single leg balance (0.90 to 0.91). In addition, for the ankle dorsiflexion range of motion, the ICC for the inter-rater reliability ranged from 0.95 to 0.96. Conclusion: STARmat^® is a reliable tool for measuring cervical proprioception, dynamic balance tests, and ankle dorsiflexion range of motion in healthy young adults.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.405-410
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• 2002

Linear motor food system control algorithm was extended to the two axis system. Among several factors considered, overshoot of the response was the most important one in minimizing position tracking error. Balance between overshoot and settling time has to be adjusted to guarantee to best tracking performance. Tracking route was carefully executed to eliminate the possible error during the machining process. Even though there exists slight discrepancy between desired mute and cutting track at the corner, precision machining could be implemented using the cutting scheme introduced.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.50-52
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• 2019

Dynamic resistance equalization is a viable technique to balance SOC of cells in a parallel-connected battery configuration due to high equalization performance, simplicity and low-cost. However, an inappropriate design of the equalization resistor can degrade the equalization performance and increase the power loss. This paper proposes an optimization process to design the equalization resistors to minimize power loss and equalization error. The simulation results show that the optimally designed resistor significantly enhance the performance in comparison with the conventional fixed-resistor equalization.

• Journal of Biomedical Engineering Research
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• v.43 no.2
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• pp.81-93
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• 2022

Proprioception training has been considered a secondary method to facilitate postural control ability. This study investigated the effects of two different proprioception training methods - the proprioceptive neuromuscular facilitation (PNF) and visual feedback-based joint position and force reproduction (VF) - on postural control advancements. Sixteen healthy people volunteered for this study, and they randomly grouped two. Each group participated in the PNF and VF training for three weeks. We evaluated each subject's proprioception levels and balance ability before and after the training. We used a clinometer and electromyogram (EMG) for VF training. The joint position reproduction test was also used to evaluate the position and force aspects of the proprioception level. We analyzed the trajectory of the center of pressure (COP) while subjects were standing on the firm floor and balance board with one leg using a pressure mat. The improvement of the position aspect of the proprioception level of the VF group (4.93±4.74°) was larger than that of the PNF group (-0.43±2.08°) significantly (p=0.012). The improvement of the anterior-posterior COP velocity of the PNF group (0.01±0.01 cm/s) was larger than that of VF group(0.002±0.01 cm/s) significantly (p=0.046). Changes of position error in the PNF group (rho=0.762, p=0.028) and tibialis anterior force reproduction error in the VF group showed a significantly strong relationship with balance ability variables. These results showed that different PNF and VF have different effects on improving two aspects of proprioception and their relationship with the balance ability. Therefore, these results might be useful for selecting proprioception or balance rehabilitation considering the clinical and patients' situation.

• Transactions of The Korea Fluid Power Systems Society
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• v.5 no.1
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• pp.13-19
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• 2008

The typical hydraulic system of hoist is composed of a hydraulic supply unit, a directional control valve, counter balance valve, and flow control valves. The flow capacity coefficients of flow control valves should be adjusted so that the hoist is operated at moderate speed and the hydraulic energy loss is minimized. However, it is difficult to adjust the flow coefficients of flow control valves by trial and error for optimal operation. Here, the steady state model of the hoist hydraulic system including the differential cylinder circuit is derived and the optimal flow capacity coefficients of flow control valves are obtained using the complex method that is one kind of constrained direct search method.

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.2
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• pp.78-84
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• 2001

The daily streamflow in the Yaluhe watershed located in the north-eastern part of China was simulated by DAWAST model and the water balance parameters of the model were calibrated by simplex method. Model verification tests were carried out. The range of root mean square error was 0.34∼1.50mm, that of percent error in volume was -16.9∼-62.0% and that of correlation coefficient was 0.727∼0.920. DAWAST model was revised to consider the phreatic evaporation from the ground water in the frozen soil by adjusting soil moisture content in the unsaturated layer at the end of the melting season. The results of estimation of the daily streamflow by the revised model were statistically improved, that is, the range of root mean square error was 0.31∼1.49mm, that of percent error in volume was -11.7∼-12.1%, and that of correlation coefficient was 0.810∼0.932. The accuracy of DAWAST model was improved and the applicability of DAWAST model was expanded to the frozen region.

• Physical Therapy Korea
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• v.20 no.2
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• pp.52-59
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• 2013

The purpose of this study was to determine the reliability and validity of the postural balance program which uses the movement accelerating field principles of posture balance training and evaluation equipment and smartphone movement accelerometer program (SMAP) in healthy young adults. A total of 34 people were appointed as the subject among the healthy young adults. By using Biodex stability system (BSS) and SMAP on the subject, the posture balance capability was evaluated. For the test-retest reliability, SMAP showed the intra-class correlation (ICC: .62~.91) and standard error measurement (SEM: .01~.08). BSS showed the moderate to high reliability of ICC (.88~.93) and SEM (.02~.20). In the reliability of inter-rater, ICC (.59~.73) as to SMAP, showed the reliability of moderate in eyes open stability all (EOSA), eyes open stability anterior posterior (EOSAP), eyes open stability medial lateral (EOSML) and eyes open dinamic all (EODA), eyes open danamic anterior posterior (EODAP), and eyes open danamic medial lateral (EODML). However, ICC showed reliability which was as low as .59 less than in other movements. In addition, BSS showed the reliability of high as ICC (.70~.75). It showed reliability which was as low as ICC (.59 less than) in other movements. In correlation to the balance by attitudes between SMAP and BSS, EOSML (r=.62), EODA (r=.75), EODML (r=.72), ECDAP (r=.64), and ECDML (r=.69) shown differ significantly (p<.05). However, the correlation noted in other movements did not differ significantly. Therefore, SMAP and BSS can be usefully used in the posture balance assessment of the static and dynamic condition with eyes opened and closed.

• Journal of International Academy of Physical Therapy Research
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• v.1 no.2
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• pp.169-175
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• 2010

The purpose of this study was to analyze and compare the effect of resistance exercise and balance exercise on proprioception and WOMAC index of patients with degenerative knee osteoarthritis. A total of 40 subjects participated in this study. The subjects were diagnosed with degenerative knee osteoarthritis and all were more than 60 years old. They were divided into three groups. Group I(n=8) was trained with resistance exercise, Group II(n=6) was trained with balance exercise and Group III(n=6) was trained with range of motion as a control. The results of this study were as follows. It was significantly indicated that the resistance exercise group and balance exercise group elicited error-reduction on proprioception goal-angle (p<.05). There was a statistically significant difference on proprioception between resistance exercise group and control(range of motion) group. There was a statistically significant reduction on WOMAC index between resistance exercise group and balance exercise group (p<.05) and on the WOMAC index between resistance exercise group and range of motion group(p<.05). In conclusion, resistance exercise and balance exercise are effective on degenerative knee osteoarthritis and resistance exercise is the most effective for improving proprioception and WOMAC index. More research on the intervention according to the degree of degenerative knee osteoarthritis is needed.

• PNF and Movement
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• v.13 no.2
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• pp.73-80
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• 2015

Purpose: The purpose of this study was to determine the effect of symmetrical-reciprocal pattern of scapula and pelvis exercises using proprioceptive neuromuscular facilitation (PNF) on gait speed and balance in patients with hemiplegia. Methods: Among the adult patients with hemiplegia that were hospitalized at Michuhol Rehabilitation Center after being diagnosed with stroke, 10 that were capable of independent walking for more than five minutes and that understood and cooperated with the therapy and test methods of this research, were selected as subjects. The therapy was implemented based on the concept of PNF, and it was performed on a low mat and a height-adjustable mat, as proscribed by the fundamental procedure for PNF. Symmetrical-reciprocal pattern of scapula and pelvis exercises were applied to the patients in the decubitus position. The therapy scheme included stabilizing reversals, rhythmic stabilization, and a combination of isotonics, rhythmic initiation, and dynamic reversals. To investigate gait speed and body trunk mobility before and after the symmetrical-reciprocal pattern of scapula and pelvis exercises were applied, walking speed for a distance of 10 m was measured and balance was tested based on the Berg-Balance scale test table. The Berg-Balance scale test was performed by one therapist to minimize any error that could occur from the subjective evaluation method used by therapists. Results: Gait speed increased by 8.97 seconds after applying the symmetrical-reciprocal pattern of scapula and pelvis exercises using the concept of PNF, showing a significant difference (p<0.01). However, balance showed no significant difference after the therapy (p>0.14). Conclusion: Exercise therapy that uses the symmetrical-reciprocal pattern of scapula and pelvis with the concept of PNF can be said to be a useful therapeutic technique that can enhance the walking speed of patients with hemiplegia.