• Physical Therapy Rehabilitation Science
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• v.6 no.3
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• pp.106-112
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• 2017

Objective: Robot assisted gait training is implemented as part of therapy for the recovery of gait patterns in recent clinical fields, and the scope of implications are continuously increasing. However clear therapy protocols of robot assisted gait training are insufficent. The purpose of this study was to investigate the effects of robot-assisted gait training applied with guidance force on balance and gait performance in persons with hemiparetic stroke. Design: Two group pre-test post-test design. Methods: Nineteen persons were diagnosed with hemiparesis following stroke participated in this study. The participants were randomly assigned to the unilateral guidance group or bilateral guidance group to conduct robot-assisted gait training. All participants underwent robot-assisted gait training for twelve sessions (30 min/d, 3 d/wk for 4 weeks). They were assessed with gait parameters (gait velocity, cadence, step length, stance phase, and swing phase) using Optogait. This study also measured the dynamic gait index (DGI), the Berg balance scale (BBS) score, and timed up and go (TUG). Results: After training, BBS scores were was significantly increased in the bilateral training group than in the unilateral guidance group (p<0.05). Spatiotemporal parameters were significantly changed in the bilateral training group (gait speed, swing phase ratio, and stance phase ratio) compared to the unilateral training group (p<0.05). Conclusions: The results of this study suggest that robot-assisted gait training show feasibility in facilitating improvements in balance and gait performance for subacute hemiparetic stroke patients.

• PNF and Movement
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• v.17 no.3
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• pp.339-351
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• 2019

Purpose: This study identified the effects of dual-task gait training on balance, gait function, and activity of daily living in patients with Parkinson's disease. Methods: This study used a single-subject design. Two patients with Parkinson's disease participated in this study. Dual-task gait training was performed 1 hour per day 8 times during intervention phase. The subjects were measured 8 times in the baseline phase, 8 times in the intervention phase, and 8 times in the follow-up phase. The outcome measurements included a timed up and go test (TUG), a Berg balance scale (BBS), a 10 meter walk test (10MWT), a 6 minute walk test (6MWT), a dynamic gait index (DGI) and a Korean modified Barthel index (K-MBI). Results: When compared to the average of the baseline process, the data collected during the intervention period showed that the TUG and 10MWT results improved and the tendency line was above the baseline. In addition, BBS, 6MWT, DGI, and K-MBI values for both patients increased remarkably after the training. Conclusion: The results of this study revealed that dual-task gait training may be helpful to improve balance, walking function, and activity of daily living for patients with Parkinson's disease. Further studies need to confirm our findings.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.3
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• pp.760-764
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• 2005

This research was performed to investigate protective effect of Sophora Subprostrata fractions against focal ischemic brain damage after middle cerebral artery(MCA) occlusion. Rats were divided into six groups: MCA-occluded group(Control); each administered groups with Sophora Subprostrata total phase(Total), Sophora Subprostrata Aqueous phase (Aqueous), Sophora Subprostrata BuOH phase(BuOH), and Sophora Subprostrata Alkaloid phase(Alkaloid) after MCA-occlusion; sham-operated group(Sham). The right MCA was occluded by A poly-L-lysine coated 4-0 nylon suture thread through the internal carotid artery permanently. Sophora Subprostrata and fractions were administered orally(5mg/ml) for 7 days after MCA-occlusion. The behavior of ischemic rats were examined at 24 hours, 3, 5 and 7 days after MCA-occlusion from the views of 4 different aspects: posture & balance tests(4 subtests), reflex tests(6 subtests), muscle-tone tests(3 subtests), and foot-fault test. The results showed that 1) in muscle tone test, Sophora Subprostrata total phase only increased reduced muscle tone function from 3 to 7 days, 2) in reflex test, Sophora Subprostrata total and Aqueous phase increased fast recovery from 24 hours and 3 days, 3) in posture & balance test, Sophora Subprostrata total and Aqueous phase increased fast recovery from 24 hours, and Sophora Subprostrata BuOH and Alkaloid phase increased posture & balance function from 3 days, but 4) in motor function test, Sophora Subprostrata did not show effective recovery compared with control group. In conclusion, Sophora Subprostrata has protective effects against brain damage at the early stage of focal cerebral ischemia. Sophora Subprostrata total and Aqueous phase produced more pronounced protective effect against focal ischemic brain damage.

• Journal of Power Electronics
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• v.19 no.4
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• pp.934-943
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• 2019

A current balance problem exists in multi-phase LLC converters due to the resonant parameter tolerance. This paper presents a current balancing method for interleaved three-phase half bridge LLC converters. This method regulates the phase shift angle of the driving signals between the three phases based on a converter with a floating Y-connection. The floating midpoint voltage has different influences on each phase current and makes the three-phase current balance performance better than midpoint non-floating systems. Phase shift control between modules can further regulate the midpoint voltage. Then three phase current sharing is realized without adding extra components. The current distributions in a midpoint non-floating system and a midpoint floating system are compared. Then the principle and implementation of the proposed control strategy are analyzed in detail. A 3kW prototype is built to verify the validity and feasibility of the proposed method.

• Physical Therapy Rehabilitation Science
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• v.3 no.1
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• pp.49-54
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• 2014

Objective: This study aimed to identify how various applications of weight bearing on the affected side of hemiplegia patients affect the ability of balance keeping of the affected leg and the gait parameters. Design: Cross-sectional study. Methods: Eighteen patients with hemiplegia participated in this study. There were twelve males and six females. This study investigated the effects of the single-leg stance exercise on dynamic balance, weight bearing, and gait ability compared with four conditions. Dynamic balance and weight bearing were measured using the step test (ST) of the affected side in stroke patients. In addition, gait parameters were measured using the optogait system for analysis of the spatial and temporal parameters of walking in stroke patients. Results: This study investigated the effect of the single leg stance exercise on the paralysis side. The ST showed significant findings for all conditions (p<0.05). Therefore, knee extension and flexion exercise on the affected side single-leg stance (condition 4) significantly improved dynamic balance and weight bearing on the affected side (p<0.05). In the condition of moving the knee joint in a single-leg stance was discovered that the stance phase time significantly increased more than in the condition of supporting the maximal voluntary weight on the affected side (p<0.05). Conclusions: Single-leg stance on the paralysis side with knee flexion and extension increased symmetry in weight bearing during stance phase time. This study suggests that single-leg stance exercises augments improved gait function through sufficient weight bearing in the stance phase of the affected side.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.6
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• pp.23-30
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• 2013

This paper shows the method of winding connection and the balance of three phase of dual inverter systems used for offshore wind power generator. In order to satisfy low cost manufacturing of large scaled wind generator, the number of slot per pole per phase should be reduced. For this reason, in this research, the number is selected as '1' which is the minimum number that stator can have. Based on the prototype machine, three types of machine for the analysis are selected, and various performances especially in terms of electrically balanced condition are also investigated. Moreover, in this paper, new inductance modeling of dual 3-phase considering cross-coupling between two inverter systems is proposed. The several inductances such as mutual-, synchronous inductances are studied. By using FEA, based on calculated the flux linkage of d and q-axis, the validity of the proposed inductance modeling is confirmed.

• Journal of the Korean Operations Research and Management Science Society
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• v.23 no.4
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• pp.63-73
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• 1998

With the success of flexible manufacturing systems(FMSs), flexible assembly systems(FASs) have been developed to automatic factories further. As in a cellular FMS, a celluar FAS is considered as the most flexible and feasible assembly systems configuration. This paper presents a method for the integrated layout design in cellular FASs. Unlike the traditional paper, this paper deals with the formation of cells and the layout of cells for jobs with operation times on different machines. The procedure in this paper consists of two distinct phases. The first phase presents machine arrangement in a double rows flowline. cell formation not to allow intercellular movements, and integrated layout design in cellular FASs considering the characteristics of FAS, layout, and production factors This phase uses older optimal algorithm. The second phase proposes to balance the system with an objective of reducing the degree of workload deviation in the cells. Simulated annealing method is used to balance the system. This phase also shows the integrated layout design in cellular FASs with the cost less than total cost of the first phase.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.1
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• pp.41-45
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• 2008

This paper describes a simple and straightforward method to determine phase converter reactances for the monocyclic start induction motor which have two different phase converters. In order to determine two reactances, two kinds of simultaneous equations with two unknown reactances at a specified speed are set up by the condition of balance operation. From these equation, these unknown reactances can be solved directly using the application software without any algebraic calculation. The applicability of this method is investigated by comparing with the known method by using the computed results at the starting and rated speed, and the results show good agreement each other. Using these results, the performance characteristics of this motor are computed and compared with three phase balance operation of induction motor.

• The Journal of Korean Physical Therapy
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• v.25 no.5
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• pp.303-310
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• 2013

Purpose: The purposes of this study were to evaluate the correlation of clinical tools for assessment of balance and ability of gait, in order to discriminate the phases of sit-to-walk movement of patients with stroke using the motion analysis system, and to investigate the reliability of the phase of sit-to-walk movement according to functional ability of patients with stroke. Methods: Twenty -one patients participated (men 17, women 4) in this study. Sit-to-walk movement of all patients was recorded by the motion analysis system. Berg Balance Scale, Timed Up and Go test, Functional Reach Test, 10 meter Walk Timed Test, and Performance-Oriented Mobility Assessment were used as functional assessment tools. Results: The results of this study showed significant correlation between the phase I, II, IV and total phase duration of sit-to-walk movement and functional assessment tools. In addition, the intraclass correlation coefficient (ICC) showed high reliability in accordance with the functional ability of patients with stroke (Pearson's r 0.93 to 1.00). Conclusion: In conclusion, there is high reliability between measures of the phase of sit-to-walk movement of chronic stroke patients and the clinical assessment tool. Results of this study suggest that measurement of the phase of sit-to-walk movement can be used significantly as an intervention and a clinical tool for patients with stroke.

• Journal of Biomedical Engineering Research
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• v.24 no.5
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• pp.435-442
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• 2003

In this paper, biomechanical aspects of dynamic대학교postural responses against forward perturbations were experimentally determined simultaneous measurements of joint angles, accelerations. EMG activations, center of pressure(CoP) movements and ground reaction forces(GRF), Thirteen young healthy volunteers, stood on a flat platform, were translated into the forward direction by an AC servo-motor at two separate velocities(0.1m and 0.2m/s). In order to recover postural balance against the forward perturbation, joint motions were observed in the sequence of the ankle dorsiflexion, the knee flexion and then the hip flexion during the later acceleration phase. Both acceleration patterns at the heel and the sacrum were shown the forward acceleration pattern during the later acceleration phase and early of constant velocity phase as increasing platform velocity, respectively. Tibialis anterior(TA) for the ankle dorsiflexion and biceps femoris(BF) for the knee flexion. the primary muscle to recover the forward perturbation, was activated during the half of acceleration phase. Ankle strategy was used for slow-velocity perturbation, but mixed strategy of both ankle and hip used for the fast-velocity perturbation. In addition, parameters of perturbation such as timing and magnitude influenced the postural response against the perturbation.