• The Journal of Korean Physical Therapy
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• v.29 no.3
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• pp.142-144
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• 2017

Purpose: Few studies have addressed the effect of diurnal circadian rhythms on postural stability, and thus the aim of the present study was to examine circadian effects on static and dynamic postural stability in young adults. Methods: Twenty-four subjects (9 men, 11 women: age=$22.20{\pm}1.77$, height=$167.20{\pm}10.47$, weight=$59.85{\pm}10.66$) from a university community volunteered for this study. Static and dynamic balance testing, which recorded using a Good Balance system (Good Balance, Metitur Ltd, Finland) was conducted at 9:00, 13:00, and 17:00 hours on two consecutive days, and the sequencing of static and dynamic balance tests were randomized. Results were analyzed using the non-parametric one-way repeated Friedman test in SPSS version 18.0 (SPSS Inc., Chicago, IL, USA), and variable found to be significant were subjected to Wilcoxon post hoc testing. Results: Static and dynamic balance showed significant difference at the three times assessments (test at 9:00, 13:00, and 17:00) during circadian. In the post hoc test of static (anteroposterior distance, mediolateral distance and COP (center of pressure) velocity) and dynamic balance (performance time), 13:00 was the longer and faster than 9:00. Conclusion: These results indicated that control of postural balance is influenced by diurnal circadian rhythms, and confirm that control of postural balance is more effective and better performance in the 09:00 hours than 13:00 hours or 17:00 hours.

• Journal of International Academy of Physical Therapy Research
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• v.5 no.1
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• pp.641-646
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• 2014

The purpose of this study is to observe how balance exercise on an unstable platform and on a stable platform affects balance ability. The subjects were 35 adults in their 20s and were randomly assigned to a stable platform group and an unstable platform group. They performed balance exercise three times per week for six weeks. Balance exercise introduced by previous research was modified and complemented for use in this study. Balance ability of the subjects was measured through center of pressure(COP) area, medial-lateral displacement, and anterior-posterior displacement using a portable balance platform BT4. There was significant difference in the COP area between the unstable platform exercise group and the stable platform exercise group. In comparison in differences between the unstable platform exercise group and the stable platform exercise group after the exercise, there was significant difference in anterior-posterior movement. Therefore, exercise on an unstable platform is more effective than exercise on a stable platform in strengthening balance ability.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.962-967
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• 1991

A counter balance valve is used as one part of hydraulic motor brake system. The function of this valve is to protect over-run or free falling of inertia load. But occasionally the brake system with counter balance valve makes some undesirable problems such as pressure surges or vibrations. In this study, for the purpose of easy estimation about dynamic characteristics of hydraulic system including counter balance valve, precise formulation describing fluid dynamics and valve dynamics under various boundary conditions were made. Dynamic characteristics were analysed by numerical integration using Runge-Kutta method, because the equations in this circuit with counter balance valve contain various nonlinear terms. Propriety of this analysis method is verified by experiment. For the purpose of obtaining fundamental data for preventing instability, this study experimented the effects of the spool taper, spring constant, cylindrical choke. And we developed double acting brake system integrated counter balance valve.

• 한국기계연구소 소보
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• s.20
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• pp.27-32
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• 1990

A counter balance valve is used as one part of hydraulic motor brake system. The function of this valve is to protect over-run or free falling of inertia load. But occasionally the brake system with counter balance valve makes some undesirable problems such as pressure surges or vibrations. In this study, for the purpose of easy estimation about dynamic chrcteristics of hydraulic system including counter balance valve, precise formulation describing fluid dynamics and valve dynamics under various boundary conditions were made. dynamic caracteristics were analysed by numerical intergration using Runge-Kutta method, because the equations in this circuit with counter balance valve contain various nonlinear terms. So the analyzing method developed in this study enabled very easy estimating the relation between the performance of counter balance valve and various physical parameters related to the valve.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.217-218
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• 2007

• PNF and Movement
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• v.16 no.1
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• pp.51-58
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• 2018

Purpose: The aim of the present study was to investigate the effects of proprioceptive neuromuscular facilitation (PNF) and taping interventions on balance ability, joint position sense, and ankle joint strength. Methods: Thirty subjects who had experienced an ankle sprain within the previous 3 months participated in this study. The subjects were randomly assigned to a PNF group (n=15) or a taping group (n=15). Before and after the interventions, ankle dorsi-flexion and plantar-flexion strength, joint position error, and total center of pressure movements in one leg while in a standing position were measured. Results: Regardless of the group allocation, ankle dorsi-flexion and plantar-flexion strength significantly improved after the interventions (p<0.05). Compared to preintervention measurements, joint position errors were significantly reduced postintervention (p<0.05). The PNF intervention significantly decreased the total lateral movement of the center of pressure in the one leg standing condition (p<0.05). Conclusion: Both PNF and taping interventions improved joint position sense and ankle joint strength. In common with the findings of a previous study, the PNF intervention improved balance ability. Further study is required to investigate the effects of various PNF and taping interventions on ankle performance in subjects with chronic ankle sprains.

• Journal of Nutrition and Health
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• v.30 no.1
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• pp.32-39
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• 1997

This study was desiged to investigate the effects of calcium supplementation on the metabolism of sodium and potassium and blood pressure in seven healthy college women, aged from 19 to 21 years old. For this purpose, metabolic studies were conducted for two weeks. During the first week, the subjects ate experimental diet of which nutrients composition was similar to their usual intake. And during the consecutive second week, they ate the same experimental diet supplemented with 500mg or calcium daily. The results were summarized as follows : 1) Urinary excretion of sodium was significantly increased(p<0.05), but fecal excretion and retention of it was not affected by supplementary intake of calcium. 2) Potassium balance was not changed after additional intake of calcium. 3) Serum sodium and potassium level decreased significantly(p<0.05), but aldosterone and renin levels in serum were not changed by additional intake of calcium. 4) Systolic blood pressure(SBP) was not affected, but diastolic blood pressure (DBP) was significantly decreased (p<0.05) by supplementation of calcium. The above results showed that daily supplementary intake of calcium can be effective to decrease diastolic blood pressure through inducing the change of sodium metabolism in young women eating usual Korean diets.

• 한국전산유체공학회:학술대회논문집
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• 2003.08a
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• pp.102-105
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• 2003

The effect of the external balance strut on the wind tunnel model is investigated with simplified geometries. For this study, flat plate and elliptic wing are simulated with and without a cylinder. Pressure and wall shear stress distribution are analyzed to understand the effect of the cylinder.

• The Journal of Korean Physical Therapy
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• v.23 no.6
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• pp.71-76
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• 2011

Purpose: We investigated a better method to enhance the vestibular system including balancing by comparing the vestibular stimulation exercise (VSE) and galvanic vestibular stimulation (GVS). Methods: The study was performed with 40 subjects randomized into four groups, including a control group, a VSE group, a GVS group, and a VSE with GVS group. The subjects of VSE performed a forward and backward roll, a right side and left side roll, and an equilibrium board in vestibular stimulation training. GVS was applied for 10 minutes and the cathode and anode side were then changed and GVS was then applied for the remaining 10 minutes. GVS was applied for 20 minutes to the subjects of this group after completion of the VSE program. Results: In the control group, all conditions were significantly decreased (p<0.05) compared to the VSE with GVS group. Also, the center of pressure (CoP) surface was more significantly decreased (p<0.01) and the CoP speed was significantly decreased in the one legged stance (p<0.05) in the control group compared to the GVS group. Conclusion: These findings suggested that GVS training increases balance ability in a narrow width. VSE with GVS training is therefore recommend as the superior method. Using GVS or VSE with GVS training is considered to clinically improve balance ability by stimulating the vestibular system.

• Journal of Veterinary Clinics
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• v.36 no.6
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• pp.301-305
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• 2019

Wii^® balance board (WBB, Nintendo, Japan) is a device that can measure and record the center of pressure path length (CPPL) and 95% confidence ellipse area (Area 95) in relation to body sway. For evaluating measure of improvement after reconstruction of medial patellar luxation (MPL) in small sized dogs, A total of 6 dogs with limping and lameness gait attributed to Grade II, III or IV MPL were evaluated. Dogs were measured for difference of extension and flexion range of motion in the stifle (dROM), muscle mass, lameness, willingness to bear weight on the affected limb while standing, and willingness to lift the contralateral limb scores, CPPL and Area 95 of WBB on pre-surgery, post-surgery 4, 8 weeks. CPPL was significantly different on pre-surgery compared with post-surgery 8 weeks (p < 0.05). Except for CPPL, measured variables were significantly different on pre-surgery compared with post-surgery 4 and post-surgery 8 weeks (p < 0.01).