• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.49 no.3
• /
• pp.118-123
• /
• 2000

This paper presents an efficient algorithm for loss reduction and load balancing by sectionalizing switch operation in large scale distribution system of radial type. We use Genetic algorithm and Kruskal algorithm to solve distribution system reconfiguration. Genetic algorithm is used to minimize objective function including loss and load balancing items. Kruskal algorithm is used to satisfy the radial condition of distribution system. The experimental results show that the proposed method has the ability to search a good solution regardless of initial configuration and size of system.

• Journal of Electrical Engineering and Technology
• /
• v.12 no.3
• /
• pp.1203-1210
• /
• 2017

Switched-inductor (SL) Z-source three-level inverter is a novel high power topology. The SL based impedance network can boost the input dc voltage to a higher value than the single LC impedance network. However, as all the neutral-point-clamped (NPC) inverters, the SL Z-source three-level inverter has to balance the neutral-point (NP) potential too. The principle of the inverter is introduced and then the effects of NP potential unbalance are analyzed. A NP balancing method is proposed. Other than the methods for conventional NPC inverter without Z-source impedance network, the upper and lower shoot-through durations are corrected by the feedforward compensation factors. With the proposed method, the NP potential is balanced and the voltage boosting ability of the Z-source network is not affected obviously. Simulations are conducted to verify the proposed method.

• Journal of the Korean Society of Physical Medicine
• /
• v.17 no.4
• /
• pp.103-111
• /
• 2022

PURPOSE: This study was performed to investigate the effects of the whole-body vibration exercise combined with ankle joint mobilization on the gait and balancing ability in patients with hemiplegic stroke. METHODS: A total of 19 patients at a rehabilitation hospital who had suffered a hemiplegic stroke were randomly assigned to the experimental group (whole-body vibration exercise combined with ankle joint mobilization, n=10) or control group (whole-body vibration exercise, n=9). All participants underwent 30 min of comprehensive rehabilitation therapy (5 × /week for 6 weeks). Additionally, the experimental group performed the whole body vibration exercise and ankle joint mobilization (15 minutes each, 30 minutes total, 3 × / week for 6 weeks). In the control group, only the whole- body vibration exercise was performed in the same manner and not the ankle joint mobilization. The gait and balancing abilities were measured before and after the 6-week training. RESULTS: Significant improvements were observed in the 10-m walk test, timed up-and-go (TUG) test, center of pressure (COP) path length, and COP path velocity in the experimental group (p < .05). The experimental group showed a larger decrease in the COP path length and velocity than the control group (COP path length, -10.27 mm vs. -3.67 mm, p < .05; COP path velocity, -.33 cm/sec vs. -.13 cm/sec, p < .05, respectively). CONCLUSION: The whole-body vibration exercise combined with ankle joint mobilization could be effective in improving the gait and balancing ability of stroke patients and could also be more effective for improving the static balance ability than the general whole-body vibration exercise alone.

• PNF and Movement
• /
• v.12 no.1
• /
• pp.1-5
• /
• 2014

Purpose: The purpose of this study was to investigate PNF exercises for balance ability in elderly. Methods: This is a literature study with books and articles. Results: The balance ability in elderly is reduced by decreasing proprioception, visual and vestibular sensation. PNF exercise is highly efficient for functional activities to control posture and movement. It is also highly efficient for balance ability in elderly. This is considered effective exercise program for maintain and to promote balance ability in elderly. Conclusion: PNF exercise is highly efficient for functional activities to control posture and movement. In addition, it is also efficient for balancing posture and movement in cooperation with visual information and vestibular system. This exercise is considered to be effective exercise program to maintain posture and improve balance ability.

• Journal of International Academy of Physical Therapy Research
• /
• v.3 no.1
• /
• pp.370-377
• /
• 2012

This study examines the effects of different environments on the application of hemiplegia patients circuit balance training. Group 1 performed circuit balance training without any auditory intervention Group 2 performed training in noiseless environments and Group 3 performed training in white noise environments. First, among lower extremity muscular strength evaluation items, maximum activity time(MAT) was not significantly different(p>.05). Maximum muscle strength(MMS) increased significantly in Group 3(p<.01), there was no significant difference in MMS among the groups. Average muscle strength(AMS) indexes also significantly increased in Group 3(p<.01), there was no significant difference in AMS among the groups. Second, among balancing ability evaluation items, Berg's balance scale(BBS) scores significantly increased in all groups(p<.05), BBS scores were significantly difference among the groups. Based on the results, Group 1, 2 and Group 1, 3 showed significant increases (p<.05). Functional reach test(FRT) values significantly increased in Group 2, 3(p<.05), and there was no significant difference in FRT values among the groups. Timed up and go(TUG) test values significantly decreased in Group 2, 3(p<.05), and there was no significant difference in TUG test values among the groups. Third, among walking speed evaluation items, the time required to walk 10m significantly decreased in all groups(p<.05), and there was no significant difference in the values among the groups. Average walking speeds showed significant increases in Group 1, 3(p<.05), and there was no significant difference in the values among the groups. Based on the results of this study, noise environments should be improved by either considering auditory interventions and noiseless environments, or by ensuring that white noise environments facilitate the enhancement of balancing ability.

• The Journal of Korean Physical Therapy
• /
• v.28 no.3
• /
• pp.189-194
• /
• 2016

Purpose: This study focuses on influence of ankle stabilization training on balance ability and lower limb muscle activation of soccer player with functional ankle instability. Methods: Subjects were grouped into ankle stabilization training group using biofeedback comprised of 15 subjects and general exercise group of 15. The training was conducted for 30 minutes, 3 times a week for 8 weeks in total. All 30 football players conducted plyometric training for 30 minutes before main training. To evaluate balance ability, biorescure was used to measure whole path length and surface area and surface electromyography (EMG) system was used to measure tibialis anterior, tibialis posterior, and soleus to evaluate lower limb muscle activation. Results: The experiment group showed significant difference to the comparison group in regard of whole path length and surface area which represents balancing capability and muscle activation of tibialis anterior, tibialis posterior, and soleus. Conclusion: Therefore, ankle stabilization training using biofeedback is more effective in enhancing balance ability and lower limb muscle activation than general exercise.

• The Journal of the Acoustical Society of Korea
• /
• v.10 no.2
• /
• pp.13-22
• /
• 1991

The presence of an unbalanced mass is originated the common source of vibration in machines with rotating rotor. In this study, the unbalanced rigid rotor mounted on an overhang shaft is balanced using the static balancing procedure, and the compensation mass is estimated by the phase angle method and four run method. Also, the reduction of vibration level before and after balancing is examined. In the experimental results, it is shown that the vibration due to the unbalanced mass is decreased by eliminating the effect of the unbalance. Above all, the four run method is proved more effective on the ability of vibration reduction, in small unbalanced mass, the phase angle method.

• Journal of Korea Game Society
• /
• v.20 no.4
• /
• pp.77-88
• /
• 2020

Recently, interest in game streaming is high in cloud-based gaming. In game streaming, remote game servers perform graphics rendering and stream the resulting scene images to clients' device on the Internet. We model the client-server allocation (CSA) problem for balancing the GPU load between servers in a game streaming environment as an optimization problem, and propose a simulated annealing-based method. The features of our method are that the method takes into account the constraints on network delay and has the ability to automatically adjust the frame rate of game sessions if necessary.

• Journal of Korean Physical Therapy Science
• /
• v.18 no.1
• /
• pp.1-10
• /
• 2011

Purpose: Study on the effect of the use of Proprioceptive Neuromuscular Facilitation(PNF) method by use of the direction and charge regulation which is the advantage of the Thera-band therapy on the walks and balances in old people and comparison with the result after applying the general PNF technique. Method: The study has been performed on 30 females over 65 years old. The study has been done by dividing the object group in 3 patterns, which are number 1, the comparison group of 10, two ones that are applied the PNF technique using Thera-band and third, the ones that are applied only the PNF technique. For the PNF and the Thera-band using PNF, we have divided the group into Combination of Isotonic technique and the Rhythmical stabilization technique according to the patient's acquaintance pattern and applied them to the patient's body. Evaluation was the balancing ability which was calculated by using the BIODEX Balance system / FRT and for the evaluation of walking ability, we have used the speed of walking for 10M / TUG. Result: In the comparison group of 10, the balancing ability and the walking ability did not change much before and after the experiment, which made it possible to compare the group with the other two easily(p>0.05). For the other two groups, we have recognized the enhancement both in the balancing ability and the walking ability, but they did not know much difference between themselves(p<0.05). Conclusion: Though there were not a big difference in the sense of improvement between the Thera-band using PNF and the PNF technique only, we could infer that these two therapy has enhanced much in the walking and balancing ability for people over 65 and through these result we can foresee that not only using the method shown in this study but also by using many advantages of Thera-band, we could diminish the tiredness of healer, enhance the efficiency of exercise in them and also by forming self training program for older people we could help them build the prevention program from falls.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
• /
• v.17 no.2
• /
• pp.19-24
• /
• 2011

Background: The elderly are likely to fall due to physical and mental atrophies, and experiencing falls may result in fear of falls and lack of self-confidence, which also leads to hesitation to physical activities and changes in walk and balance, the major variables in independent daily life. Methods: In three senior citizen centers located in D city, 22 elderly women aged 65 or older were chosen, and they filled in the questionnaire which included their agreement to voluntarily participate in the survey and medical histories. As to whether they had falls experience, the medical history items in the questionnaire asked them if they had falling down or falls once a year, twice for the three years. The objects were divided to NFE (non-falls experience) and FE (falls experience). Results: 1. As to walking abilities, significant difference was found between NFE and FE regarding walk width, stepping with two feet, and stride length while there was no significant different in terms of cadence. 2. As to balancing abilities, was significant difference between NFE and FE in terms of the physical body center area. As to the sit-to-stand, tandom gait test, no significant difference was found, and neither in the timed up and go test. Conclusions: The elderly with falls experience has inferior walking and balancing abilities to those without falls experience, and thus they are more exposed to the risks of falls.