• Journal of Technologic Dentistry
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• v.37 no.2
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• pp.63-67
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• 2015

Purpose: This study, it was observed on the effect of material and thickness of the mouth guard on postural balance in order to assess the influence of the use of a mouth guard. Methods: The mouth guards of 10 adults selected as the experiment subject was sorted into each of hard and soft material, and these were made as thickness of 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm by each of the material. Results: The results of this study are expected to wear the mouthguard hard to influence positive influence on the improvement of the muscle strength, static balance. Conclusion: Suggest the need for additional research on dynamic balance.

• PNF and Movement
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• v.8 no.1
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• pp.51-58
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• 2010

Presbycusis or related-age hearing loss is approximately 30 percent for people aged over 65 years. The purpose of this study was to compare the relationship between the Hearing Handicap Inventory for the Elderly and the Berg Balance Scale for predicting and screening risk of falls in people over 65 years with diagnosed presbycusis. Thirty-five subjects all lived at the nursing home in Wonju. Disability caused presbycusis was measured using the Hearing Handicap Inventory for the Elderly, and static and dynamic balance was measured using Berg Balance Scale. Data were analyzed using Spearman correlation. Statistically significant differences were noted between two clinical meausres (r=.862, p<0.001). In conclusion, the results suggest that presbycusis may be able to predict dangerous falls in older persons.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.1
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• pp.148-156
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• 2000

For the in-line three cylinder engine whose crankshaft has a phase of 120 degrees, the total sum of unbalanced inertia forces occurring in each cylinder will be counterbalanced among three cylinders. However, parts of inertia forces generated at the No.1 and No.3 cylinders will cause a primary moment about the No.2 cylinder. In order to eliminate this out-of-balance moment, a single balance shaft has been attached to the cylinder block so that the engine durability and riding comfort may be further improved. Accordingly, the forced vibration analysis of the in-line three cylinder engine must be implemented to meet the required targets at an early design stage. In this paper, a method to reduce noise and vibration in the 800cc, in-line three cylinder LPG engine is suggested using the multibody dynamic simulation. The static and dynamic balances of the in-line three cylinder engine are investigated analytically. The multibody dynamic model of the in-line three cylinder engine is developed where the inertia properties of connecting rod, crankshaft, and balance shaft are extracted from their FE-models. The combustion pressure within the No.1 cylinder in three significant operating conditions(1500rpm-full load, 4000rpm-full load and 7000rpm-no load)is measured from the actual tests to excite the engine. The vibration velocities at three engine mounts with and without balance shaft are evaluated through the forced vibration analysis. Obviously, it is shown that the vibration of the in-line three cylinder engine with balance shaft is reduced to the acceptable level .

• Journal of Korean Physical Therapy Science
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• v.18 no.2
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• pp.73-80
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• 2011

Purpose: The purpose of this study was to investigate the correlation between the visual perception ability and the static dynamic balance ability in health elderly. Method: The Motor Free Visual Perception Test-Row Score(MVPT-RS) and MVPT-Process Time(MVPT-PT) were used for evaluating the visual perception abilities. Assessment of the balance ability was taken by using Good Balance System. In the assessment using Good Balance System, X, Y coordinate speed, anterior-posterior direction, medial-lateral direction and Velocity Movement(VM) in standing posture when eye open were measured as static balance abilities. Thirty-seven healthy elderly who live in Gwangyang participated in the experiment for 2 months, from October to November 2010. Results: 1. There were statistically significant differences of MVPT-RS, MVPT-PT, NSB-X, NSB-Y, NSB-VM, OLB-X, and OLB-VM based on the gender(p<0.05). 2. The negative correlations of MVPT-RS:NSB-Y(r=-0.354), MVPT-RS:OLB-X(r=-0.4), MVPT-RS: OLB-Y(r=-0.371), but positive correlations of MVPT-PT:DTB-T showed a statistical significance(r=0.45, p<0.05). 3. The positive correlations of NSB-X:NSB-Y(r=0.54), NSB-X: NSB-VM(r=0.848), NSB-Y:NSB-VM(r=0.531), OLB-X:OLB-Y(r=0.876), OLB-X:OLB-VM(r=0.872), and OLB-Y:OLB-VM(r=0.787) showed statistical significances(p<0.05). Conclusion: These results showed that the visual perception ability was correlated with some balance ability in health elderly. Especially the perception test process time(MVPT-PT) has closely related with the DTB-T. The visual perception ability is considered as a factor on the balance ability in health elderly. Further study will focus on the development of improving program of visual perception ability as an improving method of balancing ability in health elderly.

• 재활복지
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• v.17 no.4
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• pp.383-399
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• 2013

The purpose of this study was to comparison the effects of aqua-and-land based obstacle training on balance of chronic stroke patients. Subjects were randomly divided into an aqua group(n=15) and d land group(n=15). Both group received obstacle training for 40 minutes, 3 times a week during 12 weeks. Static balance was assessed by measuring the mean velocity of mediolateral, anteroposterior and sway area with the eyes open using Good Balance System. Dynamic balance was assessed by measuring Functional Reaching Test(FRT) and the Timed Up and Go test(TUG). Following the intervention, both groups showed significant changes static balance(the mean velocity of mediolateral, anteroposterior and sway area) and dynamic balance(FRT and TUG). There were significant difference in the mean velocity of mediolateral, anteroposterior, sway area, FRT and TUG between the two groups after the interventions. The results of this study suggest that the aqua group and land group were increase balance functions of chronic stroke patients. The aqua group was significantly higher than the land group for patients with chronic stroke patients. We hope that aquatic training can be useful for patients with chronic stroke patients to improve balance functions and the aqua training research for improve balance functions will be conducted continuously.

• Physical Therapy Korea
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• v.28 no.3
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• pp.200-207
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• 2021

Background: Postural control deficit is a major characteristic in patients with chronic ankle instability (CAI). Elastic ankle tapings are commonly used to facilitate postural control in patients with CAI as well as prevent relapse of a lateral ankle sprain. However, equivocal evidence exists concerning the effect of elastic ankle taping on postural control. Objects: This study aimed to evaluate the effects of elastic ankle tapings using kinesio taping (KT) and dynamic taping (DT) on static and dynamic postural control in patients with CAI. Methods: Fifteen subjects with CAI were participated in this study. The participants performed tests under three conditions (barefoot, KT, and DT). Static postural control was evaluated using the one-leg standing test (OLST) and dynamic postural control using the modified Star Excursion Balance Test (mSEBT). One-way repeated-measures analysis of variance was used to compare center of pressure (CoP) data and normalized mSEBT reach distances among the three conditions (with α = 0.05). Results: The CoP parameters (path length, ellipse area, and mean velocity) of the OLST significantly decreased on applying KT and DT compared with those when barefoot. The normalized reach distances in the anteromedial (AM), medial (M), and posteromedial (PM) directions of the mSEBT significantly increased with DT compared to that in the control condition. Further, the higher reach distances with KT compared with those in the control condition were obtained in the M and PM directions of the mSEBT. No significant differences were identified in any of the OLST and SEBT parameters between the two different taping applications. Conclusion: KT and DT improved static postural control during the OLST compared with the control condition. Moreover, these tapes improved dynamic postural control during the mSEBT compared to the control. Therefore, elastic ankle tapings are useful prophylactic devices for the prevention and treatment of ankle sprain in people with CAI.

• Journal of Power Electronics
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• v.19 no.1
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• pp.68-78
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• 2019

The emergence of high voltage conversion applications has resulted in a trend of using semiconductor device series associations. Series associations allow for operation at blocking voltages, which are higher than the nominal voltage for each of the semiconductor devices. The main challenge with these topologies is finding a way to guarantee the voltage balance between devices in both blocking and switching transients. Most of the methods that have been proposed to mitigate static and dynamic voltage unbalances result in increased losses within the device. This paper introduces a new series stack topology, where the voltage unbalances are reduced. This in turn, mitigates the switching losses. The proposed topology consists of a circuit that ensures the soft switching of each device, and one auxiliary circuit that allows for switching energy recovery. The principle for the topology operation is presented and experimental tests are performed for two modules. The topology performs excellently for switching transients on each of the devices. The voltage static unbalances were limited to 10%, while the activation/deactivation delay introduced by the lower module IGBT driver takes place in the dynamic unbalances. Thus, the switching losses are reduced by 40%, when compared to hard switching configurations.

• Journal of Korean Physical Therapy Science
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• v.15 no.2
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• pp.87-95
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• 2008

Background: Hemiplegic patients usually have difficulty maintaining balance. Balance training is a major component of there habilitation program for patients with neurological impairment. The purpose of this study was to investigate the effects of PLS(Posterior Leaf Spring), FES(Functional Electrical stimulation), treadmill training, and neurodevelopmental treatment on the improvement of balance in patients with hemiplegia. Methods: We looked into published studies from Dankook University’s electronic library databases of RISS4U, KMbase, NCBI, and MEDLIS concerning the effectiveness of any form of intervention leading to improvement of balance. All types of studies relevant to the topic that were published in English during the time period of 1986 to 2005 were included. Results: 1. There were significant differences in standing balance, dynamic activity balance, and gait speed between barefoot subjects and subjects who wore SPAFO and HPAFO(p<.05). 2. The changes in ROM and FRT related to sex, age, height, and weight part of the diagnosis, as well as experience relapse, was of meaningless value. Changes in ROM related to the duration of pain and experiences of falling down were also meaningless. However, FRT showed significant static differences(p<.05). 3. The body-weight-support treadmill training scoring of standing balance, step length, and a timed 10m walking test showed definite improvement. 4. The proprioceptive control approach improved dynamic balance in patients with hemiplegia. Conclusion: Consequently, further study is needed to verify methods when physical therapists are researching balance ability in hemiplegic patient.

• The Journal of Korean Physical Therapy
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• v.34 no.5
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• pp.212-217
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• 2022

Purpose: This study sought to investigate the effects of visual cue deprivation balance training by applying head control feedback to the balance function and the fall index in older people. Methods: The study was conducted on 26 older people at the S Hospital in Gyeongsansi. The patients were randomly divided into the experimental groupI (EGI, n=9), the experimental groupII (EGII, n=9), and the control group (CG, n=8). The three groups were trained for 30 minutes three times a week for four weeks. To assess the patients' static balance function, their limits of stability (LOS) was measured using the BioRescue system, (RM Ingenierie, France), composed of a pressure platform that can measure force in diverse ways, a computer, and a monitor. The dynamic balance function was measured using the Berg Balance Scale (BBS). Also, the fall index was measured to evaluate the risk of falling. A paired t-test was performed to compare pre- and post-training performance within the groups. One-way ANOVA was performed for comparing the three groups. A post hoc least significant difference (LSD) test was also performed. Results: The results of the LOS showed a significant difference after training in the EGI and EGII groups (p<0.05). As a result of the difference between the three groups, there was a significant difference after training (p<0.05). The results of the BBS showed a significant difference after training in the EGI group (p<0.05). As a result of the difference between the three groups, there was a significant difference after training (p<0.05). Conclusion: Visual cue deprivation balance training applying head control feedback is effective in improving the dynamic balance function in older people. It is also necessary to constantly maintain the head orientation by feedback and to properly control the head movement.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.10
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• pp.882-889
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• 2008

A humanoid is a robot with its overall appearance based on that of the human body. When the humanoid moves or walks, dynamic forces act on the body structure. Although the humanoid keeps the balance by using a precise control, the dynamic forces generate unexpected deformation or vibration and cause difficulties on the control. Generally, the structure of the humanoid is designed by the designer's experience and intuition. Then the structure can be excessively heavy or fragile. A humanoid design scenario for a systematic design is proposed to reduce the weight of the structure while sufficient strength is kept. Lower parts of the humanoid are selected to apply the proposed design scenario. Multi-body dynamics is employed to calculate the external dynamic forces on the parts and structural optimization is carried out to design the lower parts. Because structural optimization using dynamic forces directly is fairly difficult, linear dynamic response structural optimization using equivalent static loads is utilized. Topology and shape optimizations are adopted for two steps of initial and detailed designs, respectively. Various commercial software systems are used for analysis and optimization. Improved designs are obtained and the design results are discussed.