• Korean Journal of Applied Biomechanics
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• v.17 no.2
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• pp.41-50
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• 2007

The purpose of this study was to examine the effects of Task-oriented training on the balance, lapse time and MVC(Maximum Voluntary Contraction) of CVA(cerebral vascular accident) patients. The active balance equipment was used to measure of the static balance, lapse time and task-oriented training. The EMG technique was used to record muscle activitie of affected side of gluteus medius and vastus medialis. The raw EMG data were filtered with band pass filter (60Hz) to remove artifacts and then low pass filtered (20Hz) to find the linear envelope which resemble muscle tension curve. The experiment had been conducted at the department of physical therapy in J hospital in M city during 8weeks. The thirty patients experienced the stroke were participated: training group (15), control group (15). They were ambulatory with or without an assistive device. They were assessed on central perturbation(mm) in the static balance, lapse time(s) and MVC test(mV). The data were analyzed using repeated measured ANOVA. The results were as follows: After Task-oriented training, central perturbation and lapse time was significantly differences in both groups(p<.001), and MVC in gluteus medius were no significant differences in both groups, but vastus medialis was significant differences in both groups (p<.001).

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.18 no.2
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• pp.67-75
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• 2012

Background: Hemiplegic patients have the problems of the balance and weight shifting to the affected leg in walking. The aim of this study was to investigate the effect of unilateral stepping exercise combined with auditory feedback on balance and walking ability of the hemiplegic patients. Methods: Thirty hemiplegic patients were allocated in study group (n=15) or control group (n=15). General exercise and weight supporting exercise were conducted for the control group, and general exercises and unilateral stepping exercise combined with auditory feedback were conducted for the study group. Exercise were conducted three times a week for six weeks. Balance ability was measured by Berg Balance Scale (BBS), postural assessment scale for stroke (PASS), and performance-oriented mobility assessment (POMA). Walking ability was measured by time up and go test (TUG), 10m walk test (10mWT), and six minutes walk test (6MWT). Results: Balance and walking ability were significant increased in both group (p<.05). Balance and walking ability of the study group were more increased than that of the control group (p<.05). Conclusions: Unilateral stepping exercise combined with auditory feedback is more effective than weight supporting exercise to increase on balance and walking ability for the hemiplegic patients.

• The Journal of Korean Physical Therapy
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• v.24 no.5
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• pp.291-299
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• 2012

Purpose: This study examined the improved sensory, hand function, postural balance and activities of daily living (ADL) through somatosensory stimulation, such as the facilitation of functional reaching and tactile, proprioceptive stimulus of the upper limb (UL) and hand. Methods: Seventeen stroke patients having problems with motor and somatosensory deficits were selected in Bobath Memorial Hospital adult rehabilitation center. The patients were divided into two groups; the sensorimotor deficit group (SMDG) and motor deficit group (MDG). Somatosensory stimulation on the UL, physical therapy and occupational therapy were carried out three times a week over a six week these treatments were performed in both group period. To compare each group, the following assessment tools were used: such as tactile detection thresholds (TDT), two point discrimination on the affected side (TPDas), unaffected side (TPDus) stereognosis (ST) manual function test, hand function on the affected side (HFas) and unaffected side (HFus), Postural Assessment Scale for Stroke (PASS) and Korean version Modified Barthel Index (K-MBI). Results: In the SMDG, somatosensory stimulation on the UL was statistically important for TDT, TPDas, TPDus (except for the thener), ST, hand function on HFas, on HFus, PASS length of displacement with foam (LDFSEO), and K-MBI. In the MDG, somatosensory stimulation on the UL was important for TDT, TPDas, TPDus (except index finger) length of displacement with the eyes open, LDFSEO, HFas, HFus, PASS and K-MBI. In addition, there was a significant difference in the PASS between SMDG and MDG. Conclusion: Somatosensory stimulation on the UL affects the sensory, hand function, postural control and ADLs performance.

• Journal of Power Electronics
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• v.18 no.6
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• pp.1659-1669
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• 2018

An improved circulating current suppression control method is proposed in this paper. In the proposed controller, an outer loop of the average capacitor voltage control model is used to balance the sub-module capacitor voltage. Meanwhile, an individual voltage balance controller and an arm voltage balance controller are also used. The DC and harmonic components of the circulating current are separated using a low pass filter. Therefore, a multiple quasi-proportional-resonant (multi-quasi-PR) controller is introduced in the inner loop to eliminate the circulating harmonic current, which mainly contains second-order harmonic but also contains other high-order harmonics. In addition, the parameters of the multi-quasi-PR controller are designed in the discrete domain and an analysis of the stability characteristic is given in this paper. In addition, a simulation model of a three-phase MMC system is built in order to confirm the correctness and superiority of the proposed controller. Finally, experiment results are presented and compared. These results illustrate that the improved control method has good performance in suppressing circulating harmonic current and in balancing the capacitor voltage.

• The Journal of Korean Physical Therapy
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• v.27 no.5
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• pp.332-338
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• 2015

Purpose: The purpose of this study was to examine the effect of postural control and locomotion on improvement of two point discrimination (TPD), stereognosis (ST) through somatosensory training (SST) on the upper limb (UL). Methods: The subjects were 20 hemiplegia patients who have problems with unilateral neglect after stroke. The patients were divided into two groups, the experimental group (EG) and the control group (CG). In the EG, SST for TPD, ST was performed 18 times, three times a week for six weeks, together with physical therapy (PT) and occupational therapy (OT). In the CG conventional PT and OT without SST was performed for six weeks. Several assessment tools were used in comparison of groups; two point discrimination test (TPDT) on forearm (F), thenar (T), hypothenar (TH), thumb tip (TH-T), index finger tip (IN-T), stereognosis test (ST), postural assessment scale for stroke (PASS), and clinical test of sensory interaction on balance (CTSIB) and timed up and go test (TUG). Results: In the CG, conventional PT and OT resulted in statistically improved TPDT (F), ST, PASS, and TUG. In the EG, SST resulted in statistically improved TPDT (F, T, HT, TH-T, IN-T), ST, PASS, and TUG. TPDT-T, ST, and CTSIB with length of displacement with eye open (LDEO) also showed significant improvement between the groups. Conclusion: In both groups TPDT ST, PASS and TUG, and SST had effects on the UL and TPDT, ST and static postural control had greater effects compared with the PG. Therefore, we could assume that TPD and ST are very important in performing human activities including postural control and locomotion.

• Journal of the Korean Society of Physical Medicine
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• v.12 no.4
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• pp.139-146
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• 2017

PURPOSE: The purpose of this study was to systematically analyze the reliability and validity of the Korean-version of the balance assessment tools. METHODS: Two reviewers of this study independently evaluated the titles of articles and abstracts of studies published until December 2016 through electronic databases (RISS, NDSL, KISS, DBpia) using the keywords "Balance or posture or postural control or postural stability", "Test or assessment or measurement or outcome measure or assessment tool or measurement tool", "Korean version", "Reliability" and "Validity". Regarding the questions considered suitable for the purpose of this study, consensus was reached after reading the full text. Selecting journals suitable for the purpose of the study, they were analyzed as data. RESULTS: The reviewers selected nine papers suitable for the purpose of this study, and Korean-version of the balance assessment tools, included the Berg Balance Scale (BBS), Activities-specific Balance Confidence (ABC) scale, Postural Assessment Scale for Stroke (PASS), Motor Assessment Scale (MAS), Trunk Impairment Scale (TIS), Falls Efficacy Scale (FES), Tinetti-Balance scale, Fullerton Advanced Balance (FAB) scale, and Function In Sitting Test (FIST). Our study showed that the reliability and validity of the Korean-version of the balance assessment tools were high. CONCLUSION: The Korean-version of the balance assessment tools with high reliability and validity would enable physical therapists to make a more accurate evaluation of balance.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.117-120
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• 1993

In this paper, a novel DC link voltage control scheme for a single-phase PWM converter is proposed. The main idea of the control scheme is eliminating the effect of dc link voltage harmonics by using power balance of input side and output side. With the proposed strategy, faster transient response than that of conventional method using low-pass filter can be obtained. In addition, a half period current control, based at equal switching frequency, is proposed. The validity of the proposed scheme is verified by simulation results for GTO PWM converter system.

• Journal of Surface Science and Engineering
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• v.37 no.4
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• pp.220-225
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• 2004

A new ion beam extraction system is designed using a simple ion mass filter and a micro mass balance and a QMS based detecting system. A quadrupole Mass Filter is used for selective ion beam formation from inductively coupled high density plasma sources with appropriate electrostatic lens and final analyzing QMS. Also a quartz crystal microbalance is set between a QMF and a QMS to measure the etching and polymerization rate of the mass selected ion beam. An inductively coupled plasma was used as a ion/radical source which had an electron temperature of 4-8 eV and electron density of $4${\times}$10^{11}$＃/㎤. A computer interfaced system through 12bit AD-DA board can control the pass ion mass of the qmf by setting RF/DC voltage ratio applied to the quadrupoles so that time modulation of pass ion's mass is possible. So the direct measurements of ion - surface chemistry can be possible in a resolution of $1\AA$/sec based on the qcm's sensitivity. A full set of driving software and hardware setting is successfully carried out to get fundamental plasma information of the ICP source and analysed $Ar^{+}$ beam was detected at the $2^{nd}$ QMS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.8
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• pp.3555-3562
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• 2011

The purpose of this study was to investigate the effect of dual task training on postural stability and balance in chronic stroke patients. A total of 25 ambulatory hemiplegic stroke patients were recruited into this study and randomly assigned into two groups, the dual task training group (n=13) and control group (n=12). Both groups received general physical therapy for 30 minutes a day, 5 days a week during 6 weeks. In addition, dual task training group received dual task training programs for 50 minutes a day, 3 days a week during 6 weeks. The scores of Trunk Impairment Scale (TIS), Postural Assessment Scale for Stroke (PASS) and postural sway with eye opened and eye closed on the Force Plate were assessed before and after intervention. Postural stability and balance significantly improved after training in the dual task training group(p<0.05). The result suggests that dual task training is feasible and suitable for individual with chronic stroke.

• Physical Therapy Korea
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• v.26 no.3
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• pp.57-66
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• 2019

Background: Visual and somatosensory integration processing is needed to reduce pusher behavior (PB) and improve postural control in hemiplegic patients with acute stroke. Objects: This study aimed to investigate the effects of game-based postural vertical training (GPVT) on PB, postural control, and activity daily living (ADL) in acute stroke patients. Methods: Fourteen participants with acute stroke (<2 months post-stroke) who had PB according to the Burke lateropulsion scale (BLS) (score>2) were randomly divided into the GPVT group ($n_1=7$) and conventional postural vertical training (CPVT) group ($n_2=7$). The GPVT group performed game-based postural vertical training using a whole-body tilt apparatus. while the CPVT group performed conventional postural vertical training to reduce PB (30 minutes/session, 2 times/day, 5 days/week for 3 consecutive weeks). The BLS was evaluated to assess the severity of PB. And each subject's postural control ability and ADL level were assessed using the postural assessment scale for stroke (PASS), balance posture ratio (BPR), and Korean-modified Barthel index (K-MBI). Outcomes were measured pre- and post-intervention. Results: Comparison of the pre- and post-intervention assessment results showed that both interventions led to the following significant changes: decreased severity of PB scores and increased PASS, BPR, and K-MBI scores (p<.05). In particular, statistical analysis between the two groups, the BLS score was significantly decreased in the GPVT group (p<.05). And PASS, BPR, and K-MBI scores were significantly improved in the GPVT group than in the CPVT group (p<.01, respectively). Conclusion: This study demonstrated that GPVT lessened PB severity and improved postural control ability and ADL levels in acute stroke patients.