• 제어로봇시스템학회논문지
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• 제13권5호
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• pp.399-405
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• 2007

This paper deals with the controller for a stable walking of a humanoid robot using genetic algorithm. A humanoid robot has instability during walking because it isn't fixed on the ground, and its nonlinearities of the joints increase its instability. If controller isn't robust, the robot may fall down at the ground during walking because of its nonlinearities. To solve this problem, robust controller is required to reduce the effect of nonlinearities and to gain the good tracking performance. In this paper, motion controller that is based on fuzzy-sliding mode controller is proposed. This controller can remove the effect of the saturation by limitation of the input voltage. It also includes compensator for reducing the effect of the nonlinearity by backlash and PI controller improving the tracking performance. In here, genetic algorithm is used for searching the optimal gains of the controller. From the given controller, a humanoid robot can moved more preciously. All the processes are investigated through simulations and are verified experimentally in a real joint system for a humanoid robot.

• 국제물리치료학회지
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• 제9권1호
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• pp.1398-1405
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• 2018

The purpose of this study was to investigate the effect of heel off stairway walking exercise on the increase of muscle activity and balance activity of the ankle joint muscles in university students with functional ankle instability. The conservative treatment for the control group consisted of stairway walking (n=10) and the experimental group consisted of heel off stairway walking (n=11). The therapeutic intervention of the control and experimental groups was performed a total of 12 exercise sessions, 3 times per week for 4 weeks. To compare the two groups, the level of ankle disability was assessed by using the EMG, BT4 and Pedoscan in pre-treatment and post-treatment. Muscle activity increased in both the experimental groups and control groups in each group, however there was no significant difference between the groups. Balance ability did not show any significant difference. This study demonstrates that heel-off stairway walking is effective in significantly increasing muscle activity, however did not significantly improve balance ability.

• 한국공간정보시스템학회:학술대회논문집
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• 한국공간정보시스템학회 2004년도 춘계 학술발표회 논문집 제1권1호(통권1호)
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• pp.75-82
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• 2004

Many researcher's efforts have made a significant advancement of space frame structure with various portion, and it becomes the most outsanding one of space structures. However, with the characteristics of thin and long term of spacing, the unstable behavior of space structure is shown by initial imperfection, erection procedure or joint, especially space frame structure represents more. This kind of unstable problem could not be set up clearly and there is a huge difference between theory and experiment. Moreover, the discrete structure such as space frame has more complex solution, this it is not easy to derive the formulation of design about space structure. In this space frame structure, the character of rise-span ratio or load mode is represented by the instability of space frame structure with initial imperfection, and snap-through or bifurcation might be the main phenomenon. Therefore, in this study, space frame structure which has a lot of aesthetic effect and profitable for large space covering single layer is dealt. And because that the unstable behavior due to variation of inner force resistance in the elastic range is very important collapse mechanism, I would like to investigate unstable character as a nonlinear behavior with a geometric nonlinear. In order to study the instability. I derive tangent stiffness matrix using finite element method and with displacement incremental method perform nonlinear analysis of unit space structure, star dome and 3-ring star dome considering rise-span $ratio(\mu}$ and load $ratio(R_L)$ for analyzing unstable phenomenon.

• 대한정형도수물리치료학회지
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• 제22권2호
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• pp.57-63
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• 2016

Background: Instability due to ankle sprains will be accompanied by a problem of balance and pain change. Balance trainer is used to improve the ankle strength and balance ability. The purpose of this study was to evaluate the change of pain and postural balance ability in ankle joint after balance trainer application in patients with ankle sprain and instability. Methods: Twenty patients in K hospital in Incheon were enrolled. Balance trainer was applied to 10 subjects in the experimental group and 10 subjects in the Balance cushion under the same conditions as the experimental group to compare the pain and balance ability. Results: In the experimental group, there was a significant difference in the change of the pain variation. In the postural balance ability comparison, there was a significant difference in total and post - posterior comparison compared to the control, but there was no significant difference in the postural balance ability comparison. Conclusion: Pain and postural balance ability of patients with instability due to ankle sprain improved the pain and balance ability of the Balance trainer group compared to the Balance cushion training group.

• 대한물리치료과학회지
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• 제15권3호
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• pp.19-29
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• 2008

Background : Ankle inversion sprains are one of the most common injuries in sports and activities of daily living that mostly concern physically active individuals. In most researches, proprioceptive deficit, muscle weakness and/or absent coordination have been regarded as a contributing factors. Despite the high incidence of ankle sprain and instability, therapeutic approaches to properly manage the symptoms have rarely been investigated. This study aimed to identify the effect of proprioceptive exercise program that is easy to integrate in normal training program. Methods : Subjects were randomly allocated to control group and experimental group consisting of 11 and 10 patients, respectively. The conservative treatment for the control group consisted of hot packs, ultrasound and TENS. In addition, the experimental group performed 7 exercises to enhance proprioceptive function of ankle joint. The therapeutic intervention of the controland experimental groups was performed a total of 20 exercise sessions, averaging 50 hour each, 5 times per week for 4 weeks. To compare the two groups, the level of ankle disability was assessed by using the ankle injury score scale in pre- and post-treatment. Results : On assessment of post-treatment, there were statistically significant differences in the scores of all sub-items, except for ankle laxity and range of motion, and the total score of ankle injury score scale between the two groups(p<0.05). In comparison between pre- and post-treatments, the significant difference in the scores of all sub-items and total score didn't appear for the control group, while the scores of most sub-items and total score of the experimental group were shown the statistically significant difference(p<0.05). Conclusion : The findings suggest that the proprioceptive exercise program is more effective for relieving ankle disability than conservative treatment therefore, the program to improve proprioceptive function should be recommended for prevention and rehabilitation of recurrent ankle inversion injuries.

• Journal of Korean Neurosurgical Society
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• 제29권11호
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• pp.1456-1460
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• 2000

Objectives : Transpedicular screw fixation has become an important method for internal fixation in variety of disorders. However, acceleration of degeneration at the adjacent segment in any follow. The goal of this study is to review the change of motion ranges of vertebral joints adjacent to fused level in lumbar spine. Methods : This study consists of 22 patients with degenerative spinal instability. Treatment of spinal instability includes posterior fusion with transpedicular screw fixation or transpedicular screw fixation with posterior lumbar interbody fusion. The flexion-extension angle(FEA) was measured from dynamic views of lumbar spine taken both at preoperative and post operative period. Results : The FEA of upper vertebral joint adjacent(FEA-u) to a fused L4-5 level was increased(p＝0.010). The FEA-u was increased in case of L5-S1 fusion(p＝0.025). The change of FEA-u in case of L5-S1 fusion was greater than that in L4-5 fusion(p＝0.013). Conclusion : After L4-5 fusion, there seems to be more meaningful increase in FEA of L3-4 than that of L5-S1. The reason may be due to the damage of L3-4 facet joints during the operation, the other possible explanation may be the anatomical stability of L5-S1 vertebral joint. The change of FEA-u of L5-S1 fusion is increased more than that of L4-5 fusion. Because there are compensations in the adjacent vertebrae both above and below the fused L4-5, the compensatory motion in FEA-u of L5-S1 fusion was greater than that of the L4-5 fusion.

• 지질공학
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• 제18권4호
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• pp.459-470
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• 2008

절토사면의 안정과 관련하여 충북 청원군에서 보은군을 가로지르는 국도 25번을 따라 지질구조에 의하여 형성된 여러종류의 사면 파괴유형을 사례 분석을 통하여 해석하고 사면의 불안정성에 영향을 끼치는 요인을 연구하였다. 노두의 발달이 양호한 3 지점을 선정하였으며, 정면적법을 이용하여 불연속면의 방향성, 연장성, 절리의 표면 거칠기 및 암석의 일축압축강도 등 공학적 특성을 분석하였다. 연구지역은 옥천습곡대에 해당되며, 미동산층의 석영편암과 규암과 운교리층의 천매암으로 구성된다 이들 암석은 미약한 변성작용을 받은 변성퇴적암으로 구성되기 때문에 절리구조 이외의 불연속면 즉 편리와 벽개구조 등의 면구조와 습곡작용에 의한 지층의 굴곡현상이 잘 발달되어 있다. 초기의 광역습곡구조와 후기의 중첩습곡구조의 발달에 따른 절리구조의 형성으로 지층의 주향에 평행하거나 수직한 절리군 및 쐐기형 또는 가위형 절리군 등 다양한 형태의 절리가 형성되었으며 절리와 벽개구조 및 층리와 사면의 방향성이 서로 교차하여 여러 종류의 파괴양상을 일으키는 불안정 요인이 되었다. 습곡구조에 의해 사면의 방향과 층리의 방향성이 서로 일치하는 경우 평면파괴를 비롯하여 대규모 파괴를 유발시킬 수 있는 요인이 많았으며, 사면과 층리의 방향성이 서로 고각으로 교차하는 지역에서는 절리군과 벽개의 교차에 의하여 지역적인 소규모의 파괴양상을 보이는 것으로 분석되었다.

• 동국한의학연구소논문집
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• 제5권
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• pp.79-95
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• 1996

When we see normal gait, gait cycle is seperated as stance phase and swing phase. It needs 6 determinant of gait of pelvic rotation, pelvic tilt, knee joint of stance phase, ankle and foot motion, ankle and knee motion, and pelvic movement to be accomplished. In addition, a joint and muscle action is accomplished biomechanically at the same time with its gait cycle. In oriental medicine, the relationships between chang-fu physiology and meridian physiology are summaried as follows ; ${\bullet}$ chang-fu physiology : Spleen manages the extremities. Liver manages soft tissues. Liver stores blood. Kidney stores essences. Kidney manages bones. ${\bullet}$ meridian physiology : The Leg Greater Yang Meridian and meridian soft tissues The Leg Yang-Myeong Meridian and meridian soft tissues The Leg Lesser Yang Meridian and meridian soft tissues The Leg Greater Yin Meridian and meridian soft tissues The Leg Lesser Yin Meridian and meridian soft tissues The Leg Absolute Yin Meridian and meridian soft tissues Especially, we can find out relations between in a "blood supplied feet can walk well" that explains "blood regulations and by liver nourishing effects"that is the closest concept of muscle. Abnormal gaits are due to three causes as following; first, physical defect secoud, pain third, nervous system or instability of muscle. In oriental medicine, we can know relationship in "atrophy, numbness, stroke, convulsion, muscular dystrophy of knee, rheumatoid arthritis, five causes of infantile growing defects, five causes of softening, sprain". Especially, atrophy is the most important symptom. Gait evaluation should be emphasized where a point can walk 8 feet to 10 feet considering stride width, stride length, the body weight center, stride number, flexion, extension, rotation of a joint as a standard factor. The point is we should find out something strange in a patient's side, front and back view. After that we should find out its cause as an index that we can observe abnormal findings in a joint and muscle.

• 한국운동역학회지
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• 제31권3호
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• pp.155-161
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• 2021

Objective: There is a lack of studies using the 3D-2D image registration techniques on the mechanism of a shoulder injury for ice hockey players. This study aimed to analyze in vivo 3D glenohumeral joint arthrokinematics in collegiate ice hockey athletes and compare shoulder scaption with or without a hockey stick using the 3D-2D image registration technique. Method: We recruited 12 male elite ice hockey players (age, 19.88 ± 0.65 years). For arthrokinematic analysis of the common shoulder abduction movements of the injury pathogenesis of ice hockey players, participants abducted their dominant arm along the scapular plane and then grabbed a stick using the same motion under C-arm fluoroscopy with 16 frames per second. Computed tomography (CT) scans of the shoulder complex were obtained with a 0.6-mm slice pitch. Data from the humerus translation distances, scapula upward rotation, anterior-posterior tilt, internal to external rotation angles, and scapulohumeral rhythm (SHR) ratio on glenohumeral (GH) joint kinematics were outputted using a MATLAB customized code. Results: The humeral translation in the stick hand compared to the bare hand moved more anterior and more superior until the abduction angle reached 40°. When the GH joint in the stick hand was at the maximal abduction of the scapula, the scapula was externally rotated 2~5° relative to 0°. The SHR ratio relative to the abduction along the scapular plane at 40° indicated a statistically significant difference between the two groups (p < 0.05). Conclusion: With arm loading with the stick, the humeral and scapular kinematics showed a significant correlation in the initial section of the SHR. Although these correlations might be difficult in clinical settings, ice hockey athletes can lead to the movement difference of the scapulohumeral joints with inherent instability.

• The Journal of Korean Physical Therapy
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• 제33권3호
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• pp.168-177
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• 2021

Purpose: This study applies the ICF to identify the patient's body function, structure, and participation, evaluates the patient's environmental factors and individual factors, and is a high level of movement to return to the society of patients with multiple ligament injury of the knee joint. Methods: Progressive strength training and ROM exercise were performed 30 minutes a day, 5 times a week for 6 weeks. The evaluation was performed by examining the ROM, length, MMT, instability, dynamic balance, pain and depression. Results: The ROM of the knee joint was improved from 110° to 135° after intervention, and the knee flexion length decreased from 69 cm to 45 cm. Knee flexor is Good after intervention from Poor-, and knee extensor is Good+ after intervention from Poor, and the plantar flexor of the ankle joint improved from Poor- before intervention to Good after intervention and dorsi-flexor of the ankle joint improve to Good from Poor. Pain index was moderate before and after the intervention, with a score of 3, 2 after the intervention, and when maintaining the sitting cross-legged, the before intervention score was 7 to 4 after the intervention. Conclusion: The patient's posture of sitting cross-legged was maintained from 30 seconds before intervention to 14 minutes after intervention. These results were able to set the hypothesis design, intervention method and goal that the multifaceted approach of environment and individual factors as well as body function and structure area, activity and participation area using ICF checklists, it is helped the patient to return to daily life.