• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.2
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• pp.141-149
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• 2018

This paper presents a neural network controller design for complex damage to a blended wing Unmanned Aerial Vehicle(UAV): partial loss of main wing and vertical tail. Longitudinal/lateral axis instability and the change of flight dynamics is investigated via numerical simulation. Based on this, neural network based adaptive controller combined with two types of feedback linearization are designed in order to compensate for the complex damage. Performance of two kinds of dynamic inversion controllers is analyzed against complex damage. According to the structure of the dynamic inversion controller, the performance difference is confirmed in normal situation and under damaged situation. Numerical simulation verifies that the instability from the complex damage of the UAV can be stabilized via the proposed adaptive controller.

• Archives of Plastic Surgery
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• v.33 no.6
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• pp.780-783
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• 2006

Purpose: Rupture of a collateral ligament of the metacarpophalangeal joint is rare except in the thumb. The injured digit became flexed and deviated toward ulna side by the hypothenar intrinsic musculature. Incomplete rupture of a collateral ligament of the metacarpophalangeal joint can be often managed by splinting the affected digit in flexion position, however, in the case of complete tears that distraction of the ends of the ruptured collateral ligament is too great to allow repositioning by splinting. Primary repair of the ruptured collateral ligament or reattachment to bone by a pull-out wire, or tendon graft technique appears to be adequate. Methods: We report a case of instability of fifth metacarpophalangeal joint due to complete rupture of radial collateral ligament. This 18-year-old male presented pain in his right outstretched hand after trauma. The diagnosis was obtained by physical examination and simple radiography. Because of persistent instability after the initial conservative treatment, open reduction and repair surgical treatment was required. Results: The fifth metacarpophalangeal joint became free of pain and stable under forced lateral deviation. Postoperative results showed good metacarpophalangeal joint function and stability during 8 months follow-up period. Conclusion: Because of the interposition of the sagittal band between the ruptured ends of radial collateral ligament such as Stener-like lesion of the thumb, surgical repair of metacarpophalangeal joint collateral ligament of the finger was justified in case of complete laxity in full flexion.

• Journal of Korean Neurosurgical Society
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• v.37 no.4
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• pp.258-262
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• 2005

Objective: The 5th lumbar spinal nerve can be entrapped in the intraspinal zone, foraminal zone, and the extraforaminal zone simultaneously. The failure to recognize that the nerve root can be compressed in such manners may be the reason of a number of failures of surgical decompression. Here we describe a microsurgical method for the decompression of the triple entrapment of the L5 spinal nerve in 21 patients. Methods: Clinical manifestations and surgical results of twenty-one patients treated surgically under the diagnosis of the triple entrapment of the L5 spinal nerve were reviewed retrospectively. All patients were treated by the posterior midline approach for the intraspinal entrapment and by the paraspinal approach for the foraminal and the extraforaminal entrapment. Results: Pain relief was obtained in all patients immediately after surgery. The mean follow-up period after the surgery was 13 months, ranged from 6 to 24 months. The mean Numeric Rating Scale (pain score) improved from 8.9 before the surgery to 1.4 (P<0.0001). The mean ODI scores improved from 76.2 before the surgery to 13.1 (P<0.0001). Nineteen patients were satisfied with their result at the last follow-up examination. Neither complications related to the surgery, nor the spinal instability was detected. Conclusion: The triple entrapment of the 5th lumbar spinal nerve is an important pathologic entity to identify for the treatment of L5 radiculopathy. Combined medial and lateral approaches are safe, minimally invasive and it provide the complete decompression of triple entrapment of the L5 spinal nerve without causing secondary instability like after complete facetectomy.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.2
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• pp.16-23
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• 2018

Postural instability can increase the likelihood of hazardous slip and fall accidents in workplaces. The present study intended to extend understanding of the effect of abnormal neck posture on postural control during quiet standing. The effect of body fatigue on the postural control was also of primary concern. Twelve healthy undergraduate students volunteered to participate in the experiment. Standing on a force platform with the neck neutral, flexed, extended, or rotated, subjects' center of pressures (COP) were measured under the two levels of body fatigue. For the fatigue condition, Subjects exercised in a treadmill to meet the predetermined level of body fatigue. Analyzing the position coordinates of COPs, the length of postural sway path was assessed in both medio-lateral (ML) axis and anterior-posterior (AP) axis. Results showed that, in AP direction, neck extension or rotation significantly increased the sway length as compared with neck neutral. Neck extension led to greater sway length compared to neck rotation. Neck flexion did not differ from neck neutral. The sway length in the AP direction also became significantly larger as the body fatigue accumulated after treadmill exercise. In ML direction, as compared to neutral posture, the neck extension, flexion, or rotation did not significantly affect the length of postural sway path. However, the sway length seemed to increase marginally with the neck extended during the fatigued condition. This study demonstrates that abnormal neck posture may interfere with postural control during standing. The ability to maintain postural stability decreases significantly with the neck extended or rotated. Body fatigue leads to postural instability further.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.15 no.2
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• pp.63-68
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• 2009

Purpose : The purpose of this study was to investigate the effect of tensor fasciae latae length on the rotation of pelvis during one leg stance. Methods : 41 healthy adults participated in this study. The movement of the pelvis and trunk was measured using 3-dimensional motion analyzer, during one leg stance. The movement of the pelvis and trunk was collected lateral shift, rotation, side bending, and flexion-extension. Tensor fasciae latae length of subjects was measured in sidelying positon with neutral position of hip joint and flexion $90^{\circ}$ of knee. Also, the range of motion of hip exteral and interal rotaion were measured in prone position wih lexion $90^{\circ}$ of knee. The subjects were separated 2 groups that more pelvic rotation group(n=15) and less pelvic rotation group(n=15) according to the degree of pelvic rotation. Results : The more pelvic rotation group was showed significantly higher in the ROM of hip external rotation than less pelvic rotation group(p<0.05). The difference of tensor fasciae latae length not showed significant difference between groups. During one leg stance, The movement of the shifting and flexion-extension of trunk and pelvis were not showed significant difference. But the side bending and the rotation of pelvis and trunk showed significant difference between groups. Conclusion : The difference of tensor fasciae latae length not showed significantly in more pelvic rotation group and less pelvic rotation group. But, this study suggests that the pelvis instability brings the instability of the trunk during one leg stance.

• Clinics in Shoulder and Elbow
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• v.21 no.4
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• pp.234-239
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• 2018

Background: In elbow fracture-dislocation, partial excision of the comminuted radial head fracture that is not amenable to fixation remains controversial considering the accompanying symptoms. This study was undertaken to evaluate the results of radial head partial excision when the comminuted radial head fracture involved <50% of the articular surface in all-arthroscopic repair of elbow fracture-dislocation. Methods: Patients were divided into two groups based on the condition of the radial head fracture. In Group A, the patients had a radial head comminuted fracture involving <50% of the articular surface, and underwent arthroscopic partial excision. Group B was the non-excision group comprising patients with stable and non-displacement fractures. Follow-up consultations were conducted at 6 weeks and at 3, 6, 12, and 24 months after surgery. Results: In all, 19 patients (Group A: 11; Group B: 8) met the inclusion criteria and were enrolled in the study. At the final follow-up, all 19 patients showed complete resolution of elbow instability. No significant differences were observed in the range of motion, visual analogue scale score, and Mayo elbow performance score between groups. Radiological findings did not show any complications of the radiocapitellar joint. However, nonunion of the coracoid fracture was observed in 3 patients (Group A: 1; Group B: 2), without any accompanying instability and clinical symptoms. Conclusions: Considering that the final outcome is coronoid fracture fixation and lateral collateral ligament complex repair for restoring elbow stability, arthroscopic partial excision for radial head comminuted fractures involving <50% of articular surface is an effective and acceptable treatment for elbow fracture-dislocation.

• PNF and Movement
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• v.18 no.3
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• pp.343-350
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• 2020

Purpose: The purpose of this study was to determine how a shoulder complex stabilization exercise affects ball control and ball speed in elementary school baseball players with an instable scapula. Methods: The subjects of the study were 16 baseball players attending S elementary school in Kwangju Metropolitan City. A shoulder complex stabilization exercise was conducted three times per week for one hour for four weeks. Then, the participants were divided into a scapular instability group or stability group based on their lateral scapular slide test scores. The measurement tool was measured using the target, the ball speed tester (PR1000-BC). All inspections were measured before and after the mediation period to examine the change in the subjects according to the mediation period. Results: As a result of measuring ball control, there was a statistically significant difference in the variation over time (p < 0.05), and there was no statistically significant difference in the interaction between time and group (p > 0.05). As a result of the test of effectiveness between subjects, there was no statistically significant difference found among the groups (p > 0.05). In terms of ball speed, there was no statistically significant difference found in the variation over time (p > 0.05) as well as in the interaction between time and group (p > 0.05). In terms of the effectiveness between subjects, there was no statistically significant difference found among the groups (p > 0.05). Conclusion: It was found that the shoulder complex stabilization exercise could improve ball control for elementary school baseball players. It is believed that this will help prevent and solve possible sport damages experienced during training or competitions, thereby helping athletes use training methods to improve their exercise capacity and continue their careers.

• Journal of Korean Neurosurgical Society
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• v.42 no.4
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• pp.311-316
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• 2007

Objective : The objective of this study is to investigate the safety, surgical efficacy, and advantages of a polyaxial screw-rod system for posterior occipitocervicothoracic arthrodesis. Methods : Charts and radiographs of 32 patients who underwent posterior cervical fixation between October 2004 and February 2006 were retrospectively reviewed. Posterior cervical polyaxial screw-rod fixation was applied on the cervical spine and/or upper thoracic spine. The surgical indication was fracture or dislocation in 18, C1-2 ligamentous injury with trauma in 5, atlantoaxial instability by rheumatoid arthritis (RA) or diffuse idiopathic skeletal hyperostosis (DISH) in 4, cervical spondylosis with myelopathy in 4, and spinal metastatic tumor in 1. The patients were followed up and evaluated based on their clinical status and radiographs at 1, 3, 6 months and 1 year after surgery. Results : A total of 189 screws were implanted in 32 patients. Fixation was carried out over an average of 3.3 spinal segment (range, 2 to 7). The mean follow-up interval was 20.2 months. This system allowed for screw placement in the occiput, C1 lateral mass, C2 pars, C3-7 lateral masses, as well as the lower cervical and upper thoracic pedicles. Satisfactory bony fusion and reduction were achieved and confirmed in postoperative flexion-extension lateral radiographs and computed tomography (CT) scans in all cases. Revision surgery was required in two cases due to deep wound infection. One case needed a skin graft due to necrotic change. There was one case of kyphotic change due to adjacent segmental degeneration. There were no other complications, such as cord or vertebral artery injury, cerebrospinal fluid leak, screw malposition or back-out, or implant failure, and there were no cases of postoperative radiculopathy due to foraminal stenosis. Conclusion : Posterior cervical stabilization with a polyaxial screw-rod system is a safe and reliable technique that appears to offer several advantages over existing methods. Further biomechanical testings and clinical experiences are needed in order to determine the true benefits of this procedure.

• Korean Journal of Applied Biomechanics
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• v.21 no.3
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• pp.309-315
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• 2011

The purpose of this study was to evaluate the effect of asymmetric muscle force in lower extremity on dynamic balance during walking. Sixteen elementary students(age: 12.3${\pm}$0.7 yrs, height: 149.4${\pm}$9.7 cm, weight 40.6${\pm}$7.8 kg) who have no musculoskeletal disorder were recruited as the subjects. Temporal parameters, M-L inclination angle of XCoM-CoP, M-L and A-P CoP, loading rate, and decay rate were determined for each trial. For each dependent variable, a independent-sample t-test was performed to test if significant difference existed between each conditions(p<.05). The displacement of antero-posterior COP during RTO-LHC1 in SG was siginificantly smaller than corresponding value in AG. In contrast, the displacement of medio-lateral COP during RTO-LHC1 in SG was greater than those of AG. It seems that imbalance of muscle force may result in increasing the medio-lateral stance in order to minimize the instability. We found that the asymmetric muscle force in the lower extremity may be a reason for the awkward control of impact force.

• Journal of Korean Neurosurgical Society
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• v.42 no.3
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• pp.168-172
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• 2007

Objective : Hirabayashi's open-door laminoplasty is a good procedure to use to treat patients with myelopathy of the cervical spine; however, the authors have experienced problems in maintaining an open-window in cervical spines after the surgery. The authors developed a modified method of the expanded open-door laminoplasty and compared the radiological and clinical results with those of the classical method. Methods : In the modified method, wiring fixation with lateral mass screws on the contra lateral-side instead of fixing the paraspinal muscle or facet joint, as in the classical methods, was used in the open window of the cervical spine. Fifteen patients with cervical myelopathy were treated using the classical method and 12 patients were treated using the modified method. Preoperative and postoperative clinical conditions were assessed according to the Japanese Orthopedic Association (JOA) score. The radiological results were compared with the preoperative and postoperative computed tomography (CT) findings. Results : In both methods, the clinical results revealed a significant improvement in neurological function (p<0.001). Image analysis revealed that the cervical canals were continuously expanded in patients treated using the modified methods. However, authors have observed restenosis during the follow-up periods in 4 patients treated using the original method. Progression to deformity and spinal instability were not observed in any of the patients in the radiological results. Conclusion : Although analysis with a larger population and a longer follow-up period needs to be undertaken, our modified open-door laminoplasty has shown an advantage in better maintaining an open window in comparison with the Hirabayashi's open-door laminoplasty.