• Physical Therapy Korea
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• v.27 no.2
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• pp.155-161
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• 2020

Background: The consequences of falls are often debilitating, and prevention is important. In theory, the lower the center of mass (COM), the greater postural stability during standing, and a weight belt at the waist level may help to lower the COM and improve the standing balance. Objects: We examined how the limit of stability (LOS) was affected by the lowered center of mass with the weight belt. Methods: Twenty healthy individuals participated in the LOS test. After calculating each participant's COM, a weight belt was fastened ten centimeters below the COM. Trials were acquired with five weight belt conditions: 0%, 2%, 4%, 6%, and 8% of body weight. Outcome measures included reaction time, movement velocity, endpoint excursion, maximum excursion, and directional control in 4 cardinal moving directions. Results: None of our outcome variables were associated with a weight belt (p > 0.075), but all of them were associated with moving direction (p < 0.01). On average, movement velocity of the COM and maximum excursion were 31% and 18% greater, respectively, in mediolateral than anteroposterior direction (5.4°/s vs. 4.1°/s; 97.5% vs. 82.6%). Conclusion: Our results suggest that postural stability was not affected by the weight-induced lowered COM, informing the development and improvement of balance training strategies.

• The Journal of the Korea Contents Association
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• v.18 no.11
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• pp.348-352
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• 2018

BioRescue ($RMIng{\acute{e}}nierie$, Marseille, France) is able to assess dynamic and static balance when a test subject stands or sits over the platform. Although previous studies have examined the reliability of other balance measurement methods, little research has been conducted on the reliability of equipment such as BioRescue. This study examined the intra-rater and inter-rater reliability of BioRescue during balance assessment. Thirty-four healthy adults participated as subjects and two physical therapists participated as examiners to determine intra- and inter-rater reliability. BioRescue was used to conduct measurements during footprint (area and pressure), Romberg, and limit of stability tests. The footprint area and limit of stability tests yielded intra- and inter-rater reliability ICC values above 0.60 in all directions. However, the footprint pressure and Romberg tests yielded values below 0.60 in all directions. BioRescue showed good inter-rater and intra-rater reliability in measurements during footprint area and limit of stability tests. However, because the values of limits of stability show the difference between experienced and unskilled, skill is required for the accuracy of the equipment.

• Tunnel and Underground Space
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• v.7 no.2
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• pp.150-157
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• 1997

Various analytical, empirical and theoretical methods for slope stability assessment were applied on slopes to develop aggregate quarry optimally. Among them are block theory, stereographic analysis, RMR, SMR, limit equilibrium method and maximum likelihood. Test site was estimated that slopes were apt to fail although rock quality was good. Modified direction and dip angle was suggested for stability. To reduce the overbreak and to improve the stability, the vertical blasting was recommended for new subground level.

• PNF and Movement
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• v.16 no.2
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• pp.259-266
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• 2018

Purpose: This study aimed to compare balance ability according to the immersion level of virtual reality-based training for the balance enhancement of the elderly. Methods: This study included 48 elderly people aged 65 years and older (male 16, female 32). According to the immersion level of applied virtual reality training, 16, 17, and 15 persons were randomly assigned to full immersion, semi-immersion, and control groups. The subjects who were assigned to the full immersion group and semi-immersion group received virtual reality training for 6 weeks at 20 min at a time, 3 times per week. The control group received no intervention. Balance ability was evaluated by measuring the stability limit and the tandem walking test before and after the intervention. Results: Results showed significant differences among the three groups in the limit of stability of all directions and the tandem walking test after the intervention. The results of the limit of stability showed a significantly higher value in the full-immersion group than in the control group, and the results of the tandem walking test showed a significantly lower value in the full-immersion and semi-immersion groups than in the control group. Conclusion: The results indicate that the head-mounted display equipment for applying full-immersion virtual training is the most effective in enhancing the balance ability of the elderly.

• Journal of The Korean Society of Integrative Medicine
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• v.6 no.2
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• pp.45-57
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• 2018

Purpose : This study was conducted to evaluate the effects of an task oriented training program combined with action-observation on balance and gait ability of patients with chronic stroke. Method : The subjects of this study were 30 patients with hemiplegia who agreed to participate and were picked up. Participants were randomly divided into equal groups; namely, an experimental group that underwent task oriented training combined with action-observation for at least 30 minutes/day for 6 weeks and a control group that underwent general task-oriented training. Patients' balance was assessed using the Sway Length, Sway Area and Limit of Stability test. In addition, gait ability was assessed using the 10 Meter Walking Test to measure the taken to walk 10 meters. Gait time and speed taken to walk 10 meters were used to examine gait ability. Results : There were significant improvements in the subscales of the balance and gait ability test of those who participated in the action-observational training program, while the control group showed only significant changes in the evaluation items of the sway length in eyes opened condition and gait time. Conclusion : Therefore, Action-observational training program effectively improved the balance and gait ability in patients with stroke.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.3
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• pp.255-262
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• 2014

PURPOSE: This study was to investigate the effectiveness of TENS on balance in stroke patients by analyzing some components such as foot pressure, limit of stability and velocity sway after providing somatosensroy input using TENS. METHODS: Twenty five subjects participated and were randomly divided into two groups, TENS group (n=13) and control group (n=12) by the computer program. Interventions were given to subjects 5 days a week for four weeks. TENS group were treated with TENS for 60 minutes in addition to the conventional therapy which included 30-minute exercise and rehabilitation ergometer training for 15 minutes. Control group performed only conventional therapy. TENS was applied on the skin of soleus, tibialis anterior, tensor fascia latae and vastus medialis in affected side. Foot pressure, limit of stability and velocity sway for balance test were measured using Biorescue. RESULTS: TENS group was significantly increased limit of stability and foot pressure in affected side more than control group. And in eye closed condition, TENS group was significantly decreased velocity sway more than control group. CONCLUSION: The application of TENS is effective to improve the somatosensory input of affected side and to increase the motor function and balance ability.

• Advances in Energy Research
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• v.4 no.4
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• pp.255-274
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• 2016

This paper presents a novel symbiotic organisms search (SOS) algorithm to optimize both real power loss (RPL) and voltage stability limit (VSL) of a transmission network by controlling the variables such as unified power flow controller (UPFC) location, UPFC series injected voltage magnitude and phase angle and transformer taps simultaneously. Mathematically, this issue can be formulated as nonlinear equality and inequality constrained multi objective, multi variable optimization problem with a fitness function integrating both RPL and VSL. The symbiotic organisms search (SOS) algorithm is a nature inspired optimization method based on the biological interactions between the organisms in ecosystem. The advantage of SOS algorithm is that it requires a few control parameters compared to other meta-heuristic algorithms. The proposed SOS algorithm is applied for solving optimum control variables for both single objective and multi-objective optimization problems and tested on New England 39 bus test system. In the single objective optimization problem only RPL minimization is considered. The simulation results of the proposed algorithm have been compared with the results of the algorithms like interior point successive linear programming (IPSLP) and bacteria foraging algorithm (BFA) reported in the literature. The comparison results confirm the efficacy and superiority of the proposed method in optimizing both single and multi objective problems.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.210-220
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• 2005

We have analyzed the stability for cut-slopes at main street 3-2 line section in Pa-ju local industrial complex. After studying an additional boring test, laboratory test and face mapping etc., we have determined the extent of reinforcement, slope inclinations and soil strength parameter from the analysis of test results. After changing the inclination of slopes for ground limit and carrying out the analysis of slope stability, we applied the Mass Nailing Method to the site because of need for reinforcement to soil and weathered rock slopes. In slope for soft and hard rock sections, we also reinforced the sections that are difficult to obtain the safety without reinforcement in alteration zone.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1156-1163
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• 2010

The bi-directional high pile load test(BDH PLT) does not have weaknesses found in the existing bi-directional low pile load test(BDL PLT); it has strong economics, is unbound by load capacity limit and secures quality stability of working piles. In this study, Verification the field found a very high capacity level of stability and reliability of the BDH PLT, as well as outstanding field applicability. Field verifications reaffirmed the advantage of the BDH PLT device, which was capable of loading 90 MN capacities as maximum. It was also found to be durable enough to load high capacity with ease.

• Journal of International Academy of Physical Therapy Research
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• v.6 no.1
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• pp.833-839
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• 2015

The purpose of the present study is to provide exercises, together with music, that are helpful for elderly people's balancing ability, and to determine their effects in order to provide data for the promotion of elderly persons' health. Thirty elderly persons were randomly assigned to a balance training group(BTG) of 15 subjects, or a music and balance training group (music therapy + balance training [MTBTG]) of 15 subjects; intervention was implemented three times per week for six weeks. To measure the changes in their balancing ability before and after the experiment, the limit of stability, the "Timed Up and Go"(TUG) test, and the Berg Balance Scale (BBS) were measured. Changes in the limit of stability before and after the experiment were shown to be significant in both the BTG and the MTBTG. Changes in the limit of stability of the right side before and after the experiment showed statistically significant differences between the BTG and the MTBTG. Changes in the TUG test and the BBS before and after the experiment were shown to be statistically significant in both the BTG and the MTBTG. The application of music during balance training thus is considered to have a positive effect on elderly persons' balancing ability.