• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.661-664
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• 2002

A control of the body posture and movement is maintained by the vestibular system, vision, and proprioceptors. Afferent signals from those receptors are transmitted to the vestibular nuclear complex, and the efferent signals from the vestibular nuclear complex control the eye movement. The postural disturbance caused by loss of the vestibular function results in nausea, vomiting, vertigo and loss of craving for life. The purpose of this study is to develop a off-vertical rotatory system for evaluating the function of semicircular canals and otolith organs, selectively, and visual stimulation system for stimulation with horizontal, vertical and 3D patterns. The Off-vertical axis rotator which stimulates semicircular canals and otolith organs selectively is composed of a comportable chair, a DC servo-motor with reducer and a tilting table controlled by PMSM. And a double feedback loop system containing a velocity feedback loop and a position feedback loop is applied to the servo controlled rotatory chair system. Horizontal, vertical, and 3D patterns of the visual stimulation for applying head mounted display are developed. And wireless portable systems for optokinetic stimulation and recording system of the eye movement is also constructed. The Gain, phase, and symmetry is obtained from analysis of the eye movement induced by vestibular and visual stimulation. Detailed data were described.

• 대한정형외과 초음파학회지
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• 제4권1호
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• pp.33-37
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• 2011

어깨의 통증을 유발하는 흔하지 않은 원인 중 하나인 상부 관절와순 전후방 병변과 동반된 극관절와 낭종에 대한 보고는 많지 않다. 저자들은 이학적 검진과 초기 초음파 검사로 극관절와 낭종을 발견하지 못한 증례를 경험하였으며, 추가로 이학적 검진과 자기공명영상 및 상지 근전도 검사로 확인하여 수술적 치료를 시행하였다. 어깨의 통증과 근력 약화를 보이는 환자에서 초음파 검사로 명확한 원인이 발견되지 않을 경우 자세한 이학적 검진과 자기공명영상, 근전도 검사 등 추가 검사가 필요할 것으로 사료된다. 극관절와 낭종에서 초음파 검사는 제한점을 가질 수 있으며, 특히 극관절와 낭종의 (1) 크기가 작고, (2) 위치상 깊이가 깊으며, 견갑극을 따라 상부 관절와순 전후방 병변에서 발생한 경우 초음파 검사에서 관찰되지 않을 수 있다는 것을 임상의들은 염두에 두어야 할 것으로 사료된다.

• Clinics in Shoulder and Elbow
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• 제1권2호
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• pp.160-166
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• 1998

The purpose of this study was to assess the results of arthroscopic subacromial decompression in patients with chronic impingement and to evaluate the results according to the rotator cuff pathology. We evaluated the clinical results of treatment for chronic impingement syndrome in 28 patients from Feb 1996 to Feb 1997. There were twenty men and eight women in age from 24 to 72 years (mean age 51) with dominant arm involvement in sixteen patients. Follow up evaluations averaged 15(range 12-24)months. The average duration of symptoms were 15(range 6­60)months. The final diagnoses which were based on the physical examination, plain radiographs and arthroscopic findings, were stage II impingement in 16 patients and stage ill impingement in 12 patients. We excluded the patients with acromioclavicular arthritis or glenohumeral instability in this study. All patients were managed non-operatively a minimum of six months. During the operation we performed contouring and smoothing the acromial undersurface and only resecting of the anterolateral band of the coracoacromial ligament. The clinical results were quantitated using UCLA shoulder rating score. Satisfactory results were obtained in 23(80%) patients. Unsatisfactory results were obtained in 5(18%) patients with posterior cuff tear. The average UCLA pain score showed significant improvement from 2.8(constant pain) to 7.2(present during heavy activities) at final follow up. The function and active forward flexion scores also increased from their preoperative value. There was no significant differences according to the surface and severity of tear and NeeI' stage (P>0.05). These results compared favorably with those reported following open acromioplasty. While arthroscopic subacromial decompression is a demanding technique with a learning curve, it is a reliable treatment for chronic impingement syndrome. A less aggressive approach to subacromial decompression and preserving the posteromedial band of the coracoacromialligament does not appear to compromise results.

• Clinics in Shoulder and Elbow
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• 제18권2호
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• pp.86-90
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• 2015

Background: Although there are several methods for evaluating bone quality, Hounsfield units (HU), a standardized computed tomography (CT) attenuation coefficient, provide a useful tool for estimating focal bone mineral density (BMD). The aim of this study is to investigate the HU for evaluating the degree of osteoporosis in greater tuberosity with regard to anchor positioning. Methods: Forty patients diagnosed as normal on shoulder CT were included and categorized according to age and gender. Axially sectioned CT images were processed to 3-dimensional models containing information about bone quality using Mimics (14.11 platform v14.1.1.1 Materialise). Three-dimensional anchors were simulated and positioned according to 6 regions of interest (ROI) in the greater tuberosity classified using Tingart's system. Mean HU of intra-anchor volumes in the 6 regions was measured. Results: A significant decrease in HU was observed with increasing age (p=0.0001) and menopause (p<0.001). A significant difference in HU was found between male and female groups with males showing the higher values (p=0.0001). HU of proximal areas of ROI was higher than those of distal areas (p<0.005). However, although mean HU of distal posterior ROI showed the lowest values, no statistically significant difference was found between anterior, middle, and posterior regions (p=0.087). Conclusions: Mean HU of ROIs provides a tool for preoperative assessment of focal BMD, which is a factor of suture anchor stability and can be used to aid decision-making regarding secure anchor positioning for rotator cuff repair. Our data support that the most secure point is the proximal regions of ROI.

• 한국운동역학회지
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• 제19권3호
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• pp.549-555
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• 2009

본 연구의 목적은 극하근 근위축이 배구선수들의 등속성 최대토크와 운동범위에 어떠한 영향을 미치는지 알아보고자, 극하근의 근위축 소견이 있는 선수 3명, 근위축 소견이 없는 선수 5명을 대상으로 등속성 근력측정기기인 Biodex와 동작분석기기 Simi-Motion을 이용하여 측정분석 하였다. 본 연구의 결과, 극하근의 근위축이 있는 그룹과 없는 그룹 사이에 어깨 관절의 외회전 등속성 최대토크, 내회전에 대한 외회전 등속성 최대토크 비율 그리고 내회전 회전 운동범위가 유의한 차이가 있는 것으로 나타났다. 배구선수들의 극하근의 근위축을 예방하기 위해서는 어깨 관절의 기능을 고려한 외회전근의 근력강화 훈련이 중점적으로 시행되어야 하며, 이와 더불어 어깨 관절 후부 조직에 대한 유연성 훈련도 병행되어야 할 것으로 사료된다.

• 대한물리의학회지
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• 제10권4호
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• pp.113-121
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• 2015

PURPOSE: The purpose of this study was to determine the effect of shoulder external rotation on muscle activities of the scapular upward rotators during arm elevation. METHODS: Nineteen healthy subjects with no medical history of shoulder pain or upper extremity disorders were recruited for this study. Electromyography (EMG) was used to measure the muscle activities of the serratus anterior (SA), upper trapezius (UP), lower trapezius (LT) and infraspinatus (IS) muscles during arm elevation. The EMG activities were recorded while the subjects performed $90^{\circ}$ arm elevation with three different arm positions; palm down (PD), neutral position (NP), and palm up (PU). While seated in a chair, the subject was asked to raise the upper extremity in the sagittal plane in random order. Subjects performed $90^{\circ}$ arm elevations in three trials at each arm position. The mean EMG activity normalized by the maximal voluntary isometric contraction was analyzed across three arm positions. Repeated measures one-way ANOVA and the post hoc Bonferroni tests were used to determine the differences in muscle activities among the three arm positions. RESULTS: The EMG activities of the SA and IS were significantly greater in the PU condition than in the other conditions during arm elevation. No significant difference was noted between the NP and PD conditions during arm elevation. CONCLUSION: These results suggest that shoulder external rotation (palm up position) can be used to activate the SA. Therefore, we recommend a scapular protraction exercise in the palm up position for strengthening the SA.

• Clinics in Shoulder and Elbow
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• 제8권1호
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• pp.23-30
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• 2005

Purpose: This paper analyzes the results of arthroscopic bankart repair for anterior recurrent dislocation following a trauma on shoulder. Material and Methods: The subjects were twenty-three (23) cases that were available to follow up for more than eighteen months during the period from November 2001 to June 2003 and were chosen from patients to whom arthroscopic bankart repair was applied using a knotless suture anchor for their traumatic anterior recurrent dislocation on the shoulder. Their average age was 28 (ranging from 15 to 60) with 20 males and 3 females. The injury from sports activities accounted for the most cases with 14 subjects. The average follow-up period was 27 months (ranging from 18 months to 35 months). There were 19 cases of bankart lesions, 4 cases of ALPSA lesions and associated with 5 cases of partial tear in the rotator cuff. The anchors employed were knotless anchor (Mitek) for all the cases. Rowe scoring scale was adopted to judge the results after operations. Patients' subjective satisfaction and range of motion of external rotation were addressed together. Results: Rowe scores showed that 20 cases (87%) reaches the level of 'good' and hinger. The average patients' satisfaction accounted for 90 points out of 100. It was also found that external rotations averagely decreased by 6.5 degree when the range of motion was in at the side. Conclusion: There were satisfactory results of arthroscopic bankart repair using knotless suture anchors as an operative treatment for traumatic anterior recurrent dislocation on shoulder.

• Clinics in Shoulder and Elbow
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• 제20권1호
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• pp.30-36
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• 2017

Background: Isolated infraspinatus tear is very rare and clinical features are not as well known, therefore the purpose of this study was to evaluate clinical characteristics and outcomes of isolated infraspinatus tear that authors experienced. Methods: Authors reviewed 288 cases of full-thickness rotator cuff tear involving infraspinatus between 2010 and 2015, and retrospectively analyzed six cases of isolated infraspinatus tear. Perioperative clinical characteristics, postoperative functional outcomes of 6 months were investigated. Functional evaluation included visual analogue scale (VAS), range of motions, American Shoulder and Elbow Surgeons (ASES) score, and Constant score. Results: Calcific tendinitis was accompanied in 4 cases (66.7%). Three of them received steroid injection or aspiration or extracorporeal shockwave therapy. Mean preoperative pain VAS was 7.1 (range, 5-9), and mean postoperative pain VAS at 6 months later was 1.6 (range, 0-5). Preoperative muscle strength by isokinetic muscle performance test showed 52% deficit of abduction and 37.6% deficit of external rotation. All 6 patients had arthroscopic repair of the infraspinatus tendon. All the patients at the 6 months follow-up exhibited clinical improvement in the Constant score (67.8 [range, 45-77] to 89.3 [range, 81-100], p=0.029), and ASES score (52.3 [range, 30-77] to 90.0 [range, 80-100], p=0.002). There was no healing failure on imaging. Conclusions: Isolated infraspinatus tendon tear was frequently accompanied by calcific tendinitis, but pathophysiologic relationship should need more study. To rule out neurogenic etiology, magnetic resonance imaging and electromyography would be helpful. Arthroscopic infraspinatus tendon repair and supraspinatus debridement showed relatively good result in painful shoulder.

• 한국산업정보학회논문지
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• 제7권2호
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• pp.74-81
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• 2002

다중경로발생기는 일반적으로 시간지연발생부, 위상발생부, 감쇠발생부로 구성되며 주로 애널로그 방식으로 구현되어왔다. 따라서 경년변화가 발생할 수 있으며 여러 번의 A/D 변환, D/A변환과정으로 인한 신호의 충실도 저하, 미세지연을 위해 높은 주파수를 필요로 하는 단점이 있다. 본 논문은 다중경로 현상을 수학적으로 모델링하여 완전히 디지털 방식으로 구현하는 방법을 제안한다. 특히 시간지연부는 두 개의 블록으로 나누어 한 블록에서는 샘플단위의 시간지연을 만들고 나머지 한 블록에서는 섭샘플(subsample) 시간지연을 만들 수 있도록 하여 정밀한 시간지연값을 효율적으로 얻을 수 있도록 했다. 또한 시스템의 마스터 주파수도 특정한 값으로 고정할 필요도 없도록 하였다. 제안한 방법을 완전히 디지털 하드웨어로 구현해 본 논문에서 제안한 다중경로 발생 알고리듬의 타당성을 검증하였다.

• 대한인간공학회지
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• 제33권1호
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• pp.15-25
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• 2014

Objective: This study aims to analyze the factors that affect the ability to maintain dynamic sitting balance (DSB), biomechanical characteristics, and physical characteristics in spinal cord injuries (SCI) patients. Background: Virtual ski training systems, ski equipment, and training protocols for disabled skiers are being studied to spread awareness. However, few studies have been reported on the sitting balance ability associated with chair mono skiing. Method: A dynamic sitting balance border system was built to investigate the ability to maintain dynamic sitting balance in SCI patients. Trunk muscle activity was evaluated by electromyogram while conducting dynamic sitting balance tests. The trunk muscle strength was tested with a portable handheld dynamometer. Physical activity scores were measured with the physical activity recall assessment. Results: There were high levels of correlation between the ability to maintain DSB and trunk flexor strength, extensor strength, rotator strength, and physical activity score. However, height, weight, and injury level in SCI patients were not correlated with the ability to maintain DSB. Additionally, strong negative correlations were found between muscle activities of the external oblique and lumbar erector spinae muscles and the ability to perform the backward tilt test. Trunk extensor muscle activity during the ball lifting test was significantly higher than in other tests. Conclusion: The results indicate that improving trunk muscle strength and physical activity can increase the ability to maintain DSB. Application: The findings of a close relationship between trunk strength, physical activity, and the ability to maintain DSB need to be reflected in the chair mono ski training program.