• Journal of Biomedical Engineering Research
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• v.25 no.4
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• pp.301-307
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• 2004

An inverse dynamic model of lower limbs is presented to calculate joint moments during gait. The model is composed of 4 segments with 3 translational joints and 12 revolute joints. The inverse dynamic method is based on Newton-Euler formalism. Kinematic data are obtained from 3 dimensional trajectories of markers collected by a motion analysis system. External forces applied on the foot are measured synchronously using force plate. The use of developed model makes it possible to calculate joint moments for variation of parameters.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.12
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• pp.1722-1725
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• 2014

An experimental investigation of COP(center of pressure) was performed using FSR(force sensing resistor) and force plate. The FSR sensor system is used as effective device to detect the movement of human body in activities of daily living. It has been shown that the FSR provides the trajectories of COP with repeatability and reliability.

• The Journal of Korean Physical Therapy
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• v.12 no.1
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• pp.65-71
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• 2000

This study investigated the effect of anticipatory postural adjustment on balance performance in postural disturbance. Any action performed by standing subject is generally accompanied by compensatory postural activities, which reduce or abolish the postural disturbance generated by the movement and keep the subjects' center of gravity within the supporting base. These Postural activities arc triggered by either anticipatory and feedback postural control. We studied the difference of anticipatory and feedback postural control in postural disturbance. The subjects were standing on a foot plate with eyes closed, holding a lead of $5\%$ of their own body weight in their hands. The condition of anticipatory postural adjustment was applied voluntarily releases the a load. The condition of feedback postural control was applied that the load was unpredictably removed. We concluded that anticipatory postural adjustment becomes more efficient to postural performance in postural disturbance.

• Korean Journal of Applied Biomechanics
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• v.17 no.1
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• pp.9-16
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• 2007

Cutting movements frequently occur in sports and influence much Lower Extremity injuries. The purpose of this study was to compare joint motion of lower extremities to cutting angles and running velocities. Seven male subjects performed cutting movements to three angles($0^{\circ}$, $30^{\circ}$, $60^{\circ}$). Subjects were instructed to run five meters at a speed of 2.5m/s and 4.5m/s before contacting their right foot on the force plate and then change direction to the left. The Peak hip, knee and ankle joint kinematics were influenced according to the running velocities and cutting angles. In conclusion, Fast running velocity and cutting angle will may influence on the lower extremity joint instability on real game situation.

• International journal of advanced smart convergence
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• v.8 no.1
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• pp.58-64
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• 2019

In recent years, small mobile devices called personal mobility or smart mobility have attracted attention. Personal mobility refers to electric-driven personal transportation that can travel at close range and medium distance, including small electric vehicles, electric bicycles, electric motorcycles and electric scooters. Most of the electric scooters used in Korea are mainly imported from China. This is due to the fact that the price competitiveness of major components of electric scooters is owned in China. At this point, the domestic research direction is preferable for the composition and design of the electric scooter body rather than cost reduction for the components. In this study, we propose a new model of portable folding structure that is easy to use for electric scooters, which are personal vehicles using electric energy. We also made a prototype for practical use.

• The Korean Journal of Pain
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• v.13 no.2
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• pp.156-163
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• 2000

Background: Peripheral nerve injury sometimes leads to chronic neuropathic pain such as causalgia. A subset of patients with causalgia have a sympathetically maintained pain which is often evoked by cooling stimuli. However, our knowledge on adrenergic receptor types responsible for cold-evoked pain that is sympathetically dependent is lacking. The present study was conducted to investigate subtypes of adrenoceptors involved in mediating cold-evoked pain that developed following peripheral nerve injury. Methods: Neuropathic surgery was performed by a unilateral ligation of L5 and L6 spinal nerves of rats. Behavioral sign of cold-evoked pain was examined for 5 min by measuring cumulative duration of time that the rat lifted its foot off a metal plate held at cold temperature ($5^{\circ}C$). Whether cold-evoked pain behavior was affected by antagonists of various subtypes of adrenoceptors, which were administered intraperitoneally before and after the ligation, was investigated. Results: After ligation, duration of foot lifting on the ligated side at cold temperature increased as compared to the pre-operative period. This increase maintained for the entire 40-day test period. Pretreatment with alpha-antagonist phentolamine produced a suppression of cold-evoked pain behavior that was not affected by beta-antagonist propranolol pretreatment. Prazosin, alpha-1 antagonist, suppressed cold- evoked pain behavior when treated either before or after nerve ligation. On the other hand, alpha-2 antagonist yohimbine was without effect on cold-evoked pain behavior whether it was treated before or after the ligation. Conclusions: The results suggest that peripheral nerve injury develops cold-evoked pain that is sympathetically dependent, and that alpha-1 adrenoreceptor plays a critical role for the generation of this type of pain in its initiation as well as maintenance.

• Journal of Korean Foot and Ankle Society
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• v.8 no.2
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• pp.166-170
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• 2004

Purpose: To evaluate the results of MIPPO (minimal invasive percutaneous plate osteosynthesis) technique for distal tibial metaphyseal fractures. Materials and Methods: It is a retrospective study of 13 patients who were treated by MIPPO technique for distal tibial metaphyseal fractures from Jan. 2001 to Jan. 2003. The average age was 46.7 years and mean follow-up period was 13.3 months. According to AO classification, there were 8 cases of A1, 3 cases of A2, 1 case of B1 and 1 case of C2. One case of A1 was a Gustilo-Anderson type I open fracture and fibular fractures were combined in 12 cases. We applied anatomical reduction and internal fixation for the fibular fractures and internal fixation on the medial side of the tibia by MIPPO technique for distal tibial metaphyseal fractures. Clinical results were evaluated using radiographic results, Neer score, the starting time of postoperative exercise and clinical complications. Results: According to the Neer score, all cases showed satisfactory results. Active ankle ROM was started at average 2.4 weeks ($2{\sim}4$ weeks) and full weight bearing ambulation at average 5.2 weeks ($4{\sim}8$ weeks) postoperatively. Union of fractures was obtained by average 14.4 weeks ($8{\sim}18$ weeks) postoperatively. Two cases showed $5^{\circ}$ limitation of motion without functional deficits and other cases showed satisfactory ROM results. One case had $6^{\circ}$ valgus deformity without functional deficits. There were not any other complications like soft tissue problems and delayed-or non-union. Conclusion: MIPPO technique for the treatment of distal tibial metaphyseal fractures is a feasible technique with a good clinical outcomes.

• Journal of Korean Foot and Ankle Society
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• v.8 no.2
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• pp.117-120
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• 2004

Purpose: The purpose of this study was to evaluate the effect and short-term results of the modified Mau osteotomy designed by the author. Materials and Methods: Seventeen feet treated with newly designed osteotomy from 2003 to 2004 were included. We performed metatarsal osteotomy and distal soft tissue procedure on 17 feet (12 patients) and additional Akin osteotomy on 6 feet (4 patients). An oblique osteotomy was made from the neck in the dorsum, aiming proximal to the base of the first metatarsal with vertical short arm on the base. We performed long arm of osteotomy parellel to the acrylic plate which was supposed as ground plane. Preoperative radiographs and follow up radiographs at three month were used for radiologic evaluation. Results: Mean hallux valgus angle was $43.6^{\circ}$ and mean intermetatarsal angle was $20.4^{\circ}$ on preoperative weight bearing radiograph. Mean amount of correction of the hallux valgus angle was $37.5^{\circ}$ and intermetatarsal angle was $14.2^{\circ}$ at three months after operation. There was no fixation loss or malunion, and the clinical result was subjectively exellent. Conclusion: More proximal rotational axis can achieve sufficient intermetatarsal angle correction, and vertical arm can provide more stable contact. So this newly modified Mau osteotomy was considered as a good alternative procedure in the treatment of severe hallux valgus.

• Journal of Korean Foot and Ankle Society
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• v.13 no.2
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• pp.179-183
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• 2009

The triplane fracture has been described as a fracture of the distal tibial epiphysis occurring across three planes-sagittal, transverse and coronal. The characteristic pattern of fusion of distal tibial epiphysis explains the special configuration of the fragments in the triplane fracture. According to Dias-Tachdjian classification, triplane fracture is classified two part fracture, three part fracture, four part fracture and two part fracture with extension to the medial malleolus. Among four types, two part triplane fracture with extension to the medial malleolus is a relatively rare injury and generally is not treated by closed reduction. Such fractures should have an anatomic reduction and adequate fixation to restore the joint congruity and obtain an anatomic reduction of the growth plate to prevent a future growth deformity. This is usually best accomplished with an open reduction and screw fixation or k-wire fixation. We experienced two part triplane fracture with extension to medial malleolus and check the CT to define the extent of the injury completely. And then we underwent open reduction and screw fixation for the fracture. As a result, we present four cases of two part triplane fracture with extension with review of related literatures.

• Journal of Korean Foot and Ankle Society
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• v.12 no.1
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• pp.80-85
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• 2008

Purpose: To evaluate and compare the outcome between interlocking IM nailing and LCP fixation in the treatment of distal metaphyseal tibial fracture. Materials and Methods: From January 2000 to December 2007, 17 patient were treated by interlocking IM nail and 13 patient were treated by LCP fixation for distal metaphyseal tibial fracture. Results: According to AO classification, there were 2 type A1 fracture (12%), 6 type A2 fracture (36%), 3 type A3 fracture (18%), 4 type B1 fracture (24%), 1 type B3 fracture (6%), 1 type C1 fracture (6%) in interlocking IM nailing group and 1 type A2 fracture (7.7%), 2 type A3 fracture (15.4%), 3 type B1 fracture (23%), 3 type B2 fracture (23%), 3 type C1 fracture (23%), 1 type C2 fracture (7.7%) in LCP fixation group. The clinical functional outcome (according to AOFAS score) is 75.6 point in IM nailing group and 81.5 point in LCP fixation group. In IM nailing group, 65% of patient showed satisfactory result and In LCP fixation group, 77% of patient showed satisfactory result. Conclusion: There is no difference on clinical results between IM nailing and MIPPO (minimal invasive percutaneous plate osteosynthesis) group in the treatment of distal tibia fracture. But MIPPO group have higher subjective satisfactory score and less complication rate. The weakness of our study is a small case number and limited follow-up and we believe a better designed prospective study will be needed.