• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.12
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• pp.2328-2339
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• 1992

The propagation of coherent time-harmonic elastic L-and SV-waves is studied in a medium with random distribution of cylindrical inclusions. The purpose of the research is to characterize the dynamic elastic moduli and the attenuation properties of fiber-reinforced composite materials. The cylindes representing the fibers are assumed to be distributed in parallel with each other and the direction of incident waves are normal to the cylinder axes. A multiple scattering formula using the single scattering coefficients in conjunction with the Lax's quasicrystalline approximation is derived from which the dispersion relation for such medium is obtained. In order to formulate the multiple scattering interaction between cylinders, the pair correlation functions are generated by the Monte Carlo simulation technique. From the numerically evaluated complex wavenumbers, the propagation speed of the average wave, the coherent attenuation and the effective elastic moduli are presented as functions of frequency and fiber volume fraction.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.6
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• pp.585-592
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• 2014

In this study, a multibody simulator was developed to analyze the bio-mimetic motion of a lizard robot design. A RecurDyn multibody dynamics model of a lizard was created using a micro-computerized tomography scan and motion capture data. The bio-mimetic motion simulator consisted of a trajectory generator, an inverse kinematics module, and an inverse dynamics module, which were used for various walking motion analyses of the developed lizard model. The trajectory generation module produces spinal movements and gait trajectories based on the lizard's speed. Using the joint angle history from an inverse kinematic analysis, an inverse dynamic analysis can be carried out, and the required joint torques can be obtained for the lizard robot design. In order to investigate the effectiveness of the developed simulator, the required joint torques of the model were calculated using the simulator.

• Journal of the Korean Society of Physical Medicine
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• v.3 no.2
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• pp.97-102
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• 2008

Purpose : The purpose of this study was to find the effect of foot bath on blood pressure(BP) following treadmill exercise. Methode : Subject of study were forty healthy males without any cardiovascular, musculoskeletal, and neurologic diseases. Following twenty minutes walking at a speed of 5m/s on the treadmill, ten twenty subjects in experimental group received foot bath, on the dominant lower limb while sitting in chair. Foot bath was applied to the level of the lateral and medial malleoli keeping the temperature of the paraffin bath at $40{\pm}0.5^{\circ}C$. Twenty subjects in control group took a rest sitting in chair in a comfortable position. BP was measured in right brachial artery. BP was measured five times(before exercise, immediately after exercise, 5 minutes, 10 minutes, and fifteen minutes after exercise). Results : The study showed that for diastolic blood pressure, there was no significant difference between the experimental and the control group. However, systolic blood pressure(SBP) increased significantly after exercise compared with SBP before exercise (p<.05). In addition, SBP in five minutes after exercise decreased significantly compared with SBP in immediately after exercise (p<.05). On the other hand, the control group had significant difference between SBP measured before exercise and SBP measured at the other measure time (p<.05). In five minutes after exercise, SBP in experimental group had significant difference with SBP in control group (p<.05). Similarly, in ten and fifteen minutes after exercise, SBP in experimental group had significantly difference with SBP in control group (p<.05). Conclusion : Consequently it was confirmed that when foot bath was applied, the increased BP induced by the exercise returned to normal range rapidly.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.3
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• pp.39-47
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• 2018

PURPOSE: The purpose of this investigation was to conduct a systemic review of studies that examine the effects of strengthening exercise on gait ability and GMFM in children with cerebral palsy and propose a standard for cerebral palsy therapy based on a meta-analysis of the studies. METHODS: An extensive literature search was conducted using databases including the KISS (Korean studies Information Service System), RISS, DBpia, PubMed and ScienceDirect, with the following search terms: 'Strengthening Exercise,' 'Resistance Exercise,' 'Gait ability,' 'GMFM' or 'cerebral palsy'. RESULTS: Eleven studies were included in this review and the duration of the intervention varied from 5 to 24 weeks. The number of application per week was mostly 2-3 times, while 5 intervention per week was adopted in a few cases. The total number of intervention applied varied from 18 to 36 and the respective effect sizes of GMFM on crawling and sitting were very high (1.075 and .881) while those of GMFM on standing and walking were very low(.206 and .125). The effect size was for gait speed was only .221. CONCLUSION: Trunk exercise and lower limb exercise effectively improved GMFM in children with cerebral palsy, resulting in improved outcomes in sitting and crawling. The results of this study will be useful for designing evidencebased cerebral palsy therapy programs.

• Journal of Korean Physical Therapy Science
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• v.8 no.2
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• pp.961-965
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• 2001

The aim of this study is to present the basic reference data of age and specipic gait parameters for Korean Adult. The basic gait parameters were extracted from 20 Adult, 10 men and 10 women, 21 to 24 years of age using VICON 512 Motion Analyzer. The temporal gait parameters and kinematic parameters of Korean Adult similar to other western reference data. The results were as follows: 1) The mean Cadence of the male to the female were 113.5 steps/min to 117.6 steps/min. 2) The mean Walking Speed of the male to the female were 1.30 m/s, to 1.27 m/s. 3) The mean Stride Length of the male to the female were 1.35 m, to 1.30 m. 4) The mean maximal angles of pint on the pelvic tilt motion for different male to the female were $9.80^{\circ}$ to $7.75^{\circ}$. (p<0.05) 5) The mean maximal angles of pint on the hip flexion motion for different male to the female were $22.62^{\circ}$ to $27.65^{\circ}$. (p<0.05) 6) The mean maximal angles of pint on the knee flexion motion for different male to the female were $55.78^{\circ}$ to $55.49^{\circ}$. (p>0.05) 7) The mean maximal angles of pint on the ankle dorsiflexion motion for different male to the female were $12.47^{\circ}$ to $13.39^{\circ}$. (p>0.05).

• Journal of Advanced Navigation Technology
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• v.24 no.5
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• pp.444-449
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• 2020

I proposed small ambulatory robot actuators using piezoelectric benders. In order to make the motion of the biomimetic robot legs similar to the movements of the cockroaches or similar insects, two pairs of legs in the diagonal direction in the four leg structures are required to make the same movement. And elliptical displacement is realized by taking into account horizontal and vertical displacement of multimode oscillations and driving them by electrical signals with differences step by step, for example of 90° the T-shaped robot actuator showed wide range of speed (From 2 mm/sec. up to 266 mm/sec.) and ability of transportation (up to 10 g with 50 mm/s). Locomotive performance of the robot was competitive to the preceding robots, and moreover, the modular type actuators of a segmented myriapods robot could be added and removed for different tasks or performances.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.11
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• pp.6767-6773
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• 2014

The study examined the effects of trunk pattern exercise in proprioceptive neuromuscular facilitation (PNF) integrated transcranial direct current stimulation (tDCS) on the muscle activity and balance, walking speed in stroke patient. Thirty-one patients with hemiplegia due to stroke were assigned to either the experimental group (n=15) or control group (n=16). Both groups performed trunk pattern training in PNF for 3 times per week over a 6 week period for 20 minutes per session. The experimental group performed additional tDCS for 20 minutes. A comparison of the two groups after the intervention showed that the exercise program in experimental group had a more significant on the gastrocnemius, tibialis anterior and balance than the control group (p<.05). This showed that trunk pattern exercise in PNF integrated tDCS had a positive effect on the functional recovery of the lower extremity in stroke patients.

• 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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.576-579
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• 2018

Purpose : This study was conducted to evaluate the effects of an action-observational task oriented training on balance and gait ability of patients with chronic stroke. Method : The subjects of this study were 30 patients with chronic stroke who agreed to participate and were picked up. Participants were randomly divided into equal groups; namely, an experimental group that underwent action-observational task oriented training 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(SL), Sway Area (SA) and Limit of Stability (LOS) test. In addition, gait ability was assessed using the 10 Meter Walking Test (10MWT). Gait time and speed taken to walk 10 metres were used to examine gait ability. Result : There were significant improvements in the subscales of the balance and gait ability test of those who participated in the action-observational task oriented training, while the control group showed no significant changes. Conclusion : Therefore, Action-observational training effectively improved the balance and gait abiltiy in patients with chronic stroke.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.5
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• pp.480-488
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• 2008

Orthodontists often treat cases which are difficult to treat with conventional orthodontics. In such cases, it could be treated with surgical procedures with the help of an oral surgeon. Especially, transverse deficiency of the mandible can be corrected by widening the transverse width of mandibular symphysis, using distraction osteogenesis. Transverse widening of mandibular sympysis is known as a safe treatment but still complications could occur during the treatment. We are reporting some complications of cases that mandibular symphysis transverse widening were applied. Some cases showed complications because of the inappropriate osteotomy line. Since straight vertical osteotomy line was inclined to the left, only the left bony segment was likely to expand. According to bio-mechanical considerations, it will be better to perform a step osteotomy, cutting the eccentric area of the alveolar crest and the centric area of the basal symphyseal area. Complications could also occur by the failure of the distraction device. The tooth borne distraction device was attached on the lingual side of the tooth with composite resin. During the distraction period, it was impossible to obtain appropriate distraction speed and rhythm because of frequent fall off of the distraction device. Therefore, distraction device should be attached firmly with orthodontic band or bone screw, etc. Tooth mobility increasement could also occur as a complication. 'Walking teeth phenomenon' was observed during the distraction period, showing severe teeth mobility and pain during mastication. These symptoms fade out during the consolidation period. Since the patient could feel insecure and uncomfortable, it should be notified to the patient before the procedure. Finally, alveolar crestal bone loss could occur. Alveolar crestal bone loss occurred because of lack of distraction device firmness and teeth trauma caused by lower lip biting habit. Therefore, adequate firmness of the distraction device and habit control will be needed.