• Physical Therapy Korea
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• v.23 no.1
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• pp.1-10
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• 2016

Background: Patients with chronic low back pain (CLBP) functionally adapt to decreased postural control due to impaired processing of sensory information. Standing postural control has been the focus of recent research in CLBP. Change in postural control may be a risk factor for CLBP, although available studies are not conclusive. Objects: This study aimed to identify the role of partial weight supported treadmill training (PWSTT) in improving balance, dysfunction, and pain in patients with chronic low back pain. Methods: The study included 22 patients with CLBP. Patients in the control group ($n_1=8$) performed three 20 min stabilization exercise sessions per week, for 4 weeks. Patients in the full weight treadmill training group ($n_2=7$) performed treadmill training for 30 min after stabilization exercise. Patients in the PWSTT group ($n_3=7$) performed PWSTT with 20% of their body weight unloaded after stabilization exercises. By using the Biodex balance system, the dynamic balance abilities of the patients in the three groups were assessed in the quiet standing position under combined conditions of visual feedback (eyes open and closed) and platform stability (level 8). The Korean version of the Oswestry Disability Index and visual analogue scale score were used as the main measure. Results: The results of this study showed that dysfunction and pain were significantly improved in all groups. Although dynamic postural stability with eyes closed was significantly improved only in the PWSTT group (p<.05), no significant difference was found in the other groups. Conclusion: The results of this study indicate that PWSTT improved balance, dysfunction and pain in the patients with CLBP. Thus, this intervention is necessary for patients with CLBP with decreased postural control.

• PNF and Movement
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• v.5 no.2
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• pp.37-46
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• 2007

Purpose : The purpose of this study was to examine the effects of combination of isotonic and rhythmic stabilization in proprioceptive neuromuscular facilitation on trunk stability and balance in elderly people with chronic low back pain. Subjects : Thirty-two elderly people ($73.78{\pm}8.49$ years of age) who had complaints of CLBP were randomly assigned to 2 groups: experimental group and control group. Methods : Subject trained with combination of isotonic and rhythmic stabilization in proprioceptive neuromuscular facilitation for 4weeks with aim of improving trunk stability and balance. Weight distribution, trunk muscle balance, static balance ability and dynamic balance ability were measured before, at the end of training. Results : Data were analyzed using two-way ANOVA. After the exercise programs, there were significant differences in the weight distribution, trunk muscle balance and dynamic balance ability between the experimental and control group. However there was no significant difference in the one leg stance test(p<.05). Conclusion : This study suggest that PNF programs may be appropriate for improving trunk stability and balance in elderly people with CLBP.

• Physical Therapy Korea
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• v.18 no.3
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• pp.49-58
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• 2011

The purpose of this study was to evaluate the effects of bridging stabilization exercise on balance ability and gait performance in elderly women. The subjects of this study were thirty-one elderly women over 65 years old in HongSung-Gun Senior Citizen Welfare Hall. The subjects were randomly assigned into one of three groups (trunk stabilization exercise on the mat, whole body vibration, and Swiss ball) and participated in each exercise program three times a week for 4 weeks. Each exercise began in the bridging position. The dynamic balance and gait were measured by limit of stability area using force plate, Berg Balance Scale (BBS), and Timed Up and Go Test (TUG). The results were as follows: 1) The limit of stability in three groups increased significantly in anterior-posterior and medial-lateral lean after 4-weeks intervention (p<.05). 2) There were no significant differences in the limit of stability among three groups after 4-weeks intervention (p>.05). 3) The BBS and TUG in three groups increased significantly after 4-weeks intervention (p<.05). 4) There were significant differences among three groups in BBS. Post-hoc test showed that Swiss ball exercise group was significantly higher than the mat and whole body vibration groups. 5) There were no significant differences TUG among three groups after 4-weeks intervention (p>.05). In conclusion, this study suggested that 4 weeks of the bridging stabilization exercises were effective on balance and gait in all three groups. Particularly Swiss ball exercise group showed higher improvement than two other exercise groups (mat, whole body vibration group).

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.6
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• pp.79-87
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• 2003

Application of combustion stabilization devices such as baffle and acoustic cavity to liquid propellant rocket engine is investigated to suppress high-frequency combustion instability, i.e., acoustic instability. First, these damping devices are designed based on linear damping theory. As a principal design parameter， damping factor is considered and calculated numerically in the chambers with/without these devices. Next, the unbaffled chambers with/without acoustic cavities are tested experimentally for several operating conditions. The unbaffled chamber shows the peculiar stability characteristics depending on the operating condition and it is found to have small dynamic stability margin. As a result, the acoustic cavity with the present design has little stabilization effect in this specific chamber. Finally， stability rating tests are conducted with the baffled chamber, where evident combustion stabilization is observed, which indicates sufficient damping effect.

• Journal of the Korean Society of Physical Medicine
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• v.19 no.2
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• pp.29-45
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• 2024

PURPOSE: This study aimed to compare the effects of pain level, lower back pain dysfunction level, psychosocial level, hip abductor strength (HAS), number of positive lumbar instability tests, and dynamic balance (DB) by applying lumbar stabilization exercises according to the presence or absence of gluteus medius muscle weakness in chronic lower back pain (CLBP) patients with lumbar instability. METHODS: Thirty-five CLBP patients with lumbar instability were divided into the gluteus medius weakness (n = 18) and gluteus medius non-weakened (n = 17) groups using the gluteus medius manual muscle test. Intervention applied conservative physical therapy and lumbar stabilization exercises to both groups that lasted three times a week for four weeks. To compare the intervention effects, the quadruple visual analog scale (QVAS), the Korean version of the Oswestry disability index (K-ODI), fear-avoidance beliefs questionnaire (FABQ), HAS, lumbar instability tests positive response counter (LIC), and DB were measured. RESULTS: Significant differences were shown for QVAS, K-ODI, FABQ, HAS, LIC, and DB for both groups pre- and post-intervention (p < .05). Compared to the gluteus medius weakness group, the gluteus medius non-weakened group showed a significant difference (p < .05) in the changes in QVAS, K-ODI, FABQ-W, FABQ-total, and HAS. CONCLUSION: In CLBP patients with lumbar instability, having gluteus medius weakness was less effective in improving lumbar stabilization exercise than gluteus medius non-weakness regarding pain level, lower back pain dysfunction level, psychosocial level excluding physical activity, and hip abductor strength. Therefore, additional gluteus medius strengthening exercises are necessary for patients with lumbar instability and gluteus medius muscle weakness.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.3
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• pp.1-12
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• 2003

The complexity of the papermaking system accelerates interactions between a large number of variables involved. The process operation, therefore, is subject to frequent perturbations by disturbance. Dynamic modelling is a useful tool for characterizing the transient behavior and selecting the best control strategies to reject disturbances. In this study we developed a dynamic simulation model of a fine paper production process, which consists of stock preparation, wire sections, white water circulations, and broke system. It focused on dynamic simulation in its role for developing control strategies and studying control loop dynamics related to filler loading for ash control. The results emphasized the importance of filler-loading position and length of control loop for rapid ash control and process stabilization.

• PNF and Movement
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• v.14 no.3
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• pp.237-244
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• 2016

Purpose: This case report examines the influence of proprioceptive neuromuscular facilitation (PNF) combined with a dynamic neuromuscular stabilization approach on balance in patients with cerebellar atrophy. Methods: The target subject of this case report was a 34-year-old woman who was informed of the purpose of this research and voluntarily agreed to participate in it. The case report conformed to research ethics based on the Helsinki Declaration. The target subject was confirmed to have cerebellar atrophy from an unknown cause in 2009 and was diagnosed with slight ataxia. At that time, she could carry out daily activities without physical therapy. On May 19, 2015, she suffered both a subdural hemorrhage (SDH) and subarachnoid hemorrhage (SAH) in a traffic accident. She was urgently moved to the emergency room and managed by nonsurgical treatment, and then, the cerebellar atrophy and ataxia gradually deteriorated. To evaluate the patient's balance capacity before and after intervention, the trunk impairment scale (TIS), trunk impairment scale (OLST) during eye-closing/opening, timed up and go test (TUG), and visual analogue scale (VAS) were conducted. The PNF intervention program was executed for 30 min, four times a week, for three weeks. Results: The TIS and OLST during eye-closing/opening were improved by as much as a point, by 8.15 s and 6.21 s, respectively, after applying the PNF program. TUG and VAS decreased by 1.33 s and 3 points, respectively, after intervention. According to the result, the OLST during eye-closing/opening and VAS improved remarkably in comparison with those before intervention. Conclusion: As the final result of the case report, PNF intervention combined with DNSA more effectively improved the static balance capacity, such as the OLST during eye-closing/opening and VAS, compared to the dynamic balance capacity. In addition, the intervention duration and period of the exercise program are recommended to be more than 1 h a day for four weeks considering the learning ability of a patient with cerebellar atrophy.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.7
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• pp.590-596
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• 2004

A passivity-based dynamic output feedback controller design is considered for a finite collection of non-square linear systems. Design of a single controller for a set of plants i.e. simultaneous stabilization is an important issue in the area of robust control design. We first determine a squaring gain matrix and an additional dynamics that is connected to the systems in a feedforward way, then a static passivating control law is designed. Consequently, the actual feedback controller will be the static control law combined with the feedforward dynamics. A necessary and sufficient condition for the existence of the parallel feedforward compensator is given by the static output feedback formulation. In contrast to the previous result [1], a technical condition for constructing the parallel feedforward compensator is removed by proposing a new type of the parallel compensator.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.04a
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• pp.390-393
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• 2007

In this paper, applications of self recurrent neuro-fuzzy controller to stabilization of nonlinear system are considered. The architecture of self recurrent neuro-fuzzy controller is fix layer, and the hidden layer is comprised of self recurrent architecture. Also, generalized dynamic error-backpropagation algorithm is used for the learning of the self recurrent neuro-fuzzy controller. To demonstrate the efficiency of the self recurrent neuro-fuzzy control algorithm presented in this study, a self recurrent neuro-fuzzy controller was designed and then a comparative analysis was made with LQR controller through an simulation.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.12
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• pp.121-128
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• 2000

The scope of this paper is focused to the systems which have the time period and they should be necessarily studied in the sense of stability and design method of controller to stabilize the orignal unstable systems. In general, the time periodic systems or the systems having same motions during certain time interval are easily found in rotating motion device, i.e., satellite or helicopter and widely used in factory automation systems. The characteristics of the selected dynamic systems are analyzed with the new stability concept and stabilization control method based on Lyapunov direct method. The new method from Lyapunov stability criteria which satisfies the energy convergence is studied with linear algebraic method. And the numerical procedures are developed with computational programming method to apply to the practical linear periodic systems. The results from this paper demonstrate the usefulness in analysis of the asymptotic stability and stabilization of the unstable linear periodic system by using the developed simulation procedures.