• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 G
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• pp.2983-2985
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• 1999

This paper presents the attitude control of the double inverted pendulum with compliant joint. The biped robot with compliant ankle joint instead of a motor have a good contact between it's sole and ground in the uneven ground. The compliant ankle joint proposed here is composed of springs and mechanical constraint. The lower link is hinged on the plate to free for rotation in the vertical plate. The upper link is connected to the lower link through a DC motor. The DC motor is used to control the posture of the pendulum by adjusting the position of the upper link. The algorithm for controlling a proposed inverted pendulum is nonlinear feedback controller. Simulation with mathematical model are conducted to show the validity of the proposed controller.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.1201-1202
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• 2012

• Structural Engineering and Mechanics
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• 제66권1호
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• pp.1-14
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• 2018

Column is usually floating on the stone base directly with or without positioning tenon in traditional Chinese timber structure. Vertical load originated by the heavy upper structure would induce large friction force and compression force between interfaces of column foot and stone base. This study focused on the mechanical behaviors of column foot joint with consideration of the influence of vertical load. Mechanism of column rocking and stress state of column foot has been explored by theoretical analysis. A nonlinear finite element model of column foot joint has been built and verified using the full-scale test. The verified model is then used to investigate the mechanical behaviors of the joint subjected to cyclic loading with different static vertical loads. Column rocking mechanism and stress distributions of column foot were studied in detail, showing good agreement with the theoretical analysis. Mechanical behaviors of column foot joint and the effects of the vertical load on the seismic behavior of column foot were studied. Result showed that compression stress, restoring moment and stiffness increased with the increase of vertical load. An appropriate vertical load originated by the heavy upper structure would produce certain restoring moment and reset the rocking columns, ensuring the stability of the whole frame.

• The Journal of Korean Physical Therapy
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• 제28권2호
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• pp.106-111
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• 2016

Purpose: The aim of this study is to determine the effect of glenohumeral (GH) rotation position in modified knee push-up plus exercise (MKPUP) by examining the surface electromyography (EMG) amplitude in serratus anterior (SA), pectoralis major (PM), and upper trapezius (UTz) and the activity ratio of each muscle. Methods: A total of 22 healthy subjects volunteered for the study. Each subject performed the MKPUP at $0^{\circ}$, $45^{\circ}$, and $90^{\circ}$ of GH joint internal rotation. EMG of the SA and PM, UTz was compared between GH rotation positions and each muscle activity ratio. EMG was used to measure the muscle activity in terms of ratios to maximal voluntary isometric contraction (MVIC). Results: The difference in EMG activity during the exercise in three GH joint internal rotation positions was observed with the SA and the PM. The greater the GH joint internal rotation angle was, the lower the activity of the PM. In contrast, the SA showed higher activity. However, the activity of UT was similar under all conditions. The ratio of the SA and the PM was considerably greater at $90^{\circ}$ GH joint internal rotation than at $0^{\circ}$ and $45^{\circ}$. Conclusion: When excessive activation of the PM or imbalanced activation between the PM and the SA occurs, the MKPUP exercise is most effective at $90^{\circ}$ of GH joint internal rotation. Use of this position would be a beneficial strategy for selective strengthening of the SA and minimizing PM activation.

• 대한가정학회지
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• 제20권4호
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• pp.1-12
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• 1982

This study was to investigate the changes of shape of the lower limb surface, the rate of the measurement of expansion and contraction and correlation coefficient between variables caused by hip joint and knee joint movements. The results of the investigation are as follows; 1. According to the development figure of shell when the leg was raised $45^{\circ}$forward($M_{2}$), total length of F.L shortened while B.L lengthened. This result is contarary to $M_{3}$raising the leg $15^{\circ}$ backward. In both $M_{2}$, $M_{3}$movements, the rate of expansion and contraction to the course direction was insignificant. When hip joint was bent $15^{\circ}$ with knee joint $120^{\circ}$bent ($M_{4}$) and hip joint was bent $30^{\circ}$ with knee joint $90^{\circ}$ bent($M_{5}$), upper section of back hip expanded while the front hip section contracted slightly. In the Movement of sitting on the chair($M_{6}$), abdomen, front hip section and upper thight section contracted to the wale direction remarkably while the back hip section expanded conspicuously. 2. According to the rate of expansion and contraction of skin (surface) by the somatometry. In $M_{2}$, C.F.L. upper and middle thight girth contracted and B.L, C.L, L.L expanded. This fact is contarary to M3. In M4, M5, C.F.L showed remarkable contraction and C.B.L expanded remarkably. In $M_{6}$, C.B.L contracted most of all the items measured and knee girth, F.L, L.L, C.B.L, hip girth expanded conspicuously. 3. According to the correlation coefficient between variables. In various movements, the correlation among girth items commonly showed a high or middle grade, the correlation among length items also commonly showed a low grade and that girth and length items showed a very low grade commonly. Waist girth, hip grith, F.L, B.L, L.L items showed that there were significant correlation.

• The Journal of Korean Physical Therapy
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• 제28권1호
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• pp.8-13
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• 2016

Purpose: The purpose of the present current study was to examine control of upper limb multi-joint movements with differential coordination stability. To achieve the goals of the study, torque analyses were utilized to answer questions about how torque components were differed among various elbow-wrist coordination patterns. Methods: Eight self-reported right-handed college students (3 males and 5 females, mean age=20.6 yr) were volunteered. The task required participants to rhythmically coordinate the flexion-extension motions of their elbow and wrist with coordination relationship of $0^{\circ}$, $90^{\circ}$, and $180^{\circ}$relative phases between the two joints. Mean relative phase and phase stability (standard deviation of relative phase) were computed to for analysisze of overall coordination performance. To determine the figure out characteristics of torque components in elbow and wrist joints, impulse values of muscle torque (MT) and interactive torque (IT) and MT as a percentage of cycle duration (MT-PCD) were analyzed. Results: Torque results showed that the proximal elbow joint generated motions with mainly muscle efforts regardless of coordination patterns, while the distal wrist joint adjusted the coordination patterns by changing amount of MT. Impulse analyses showed that the least stable $90^{\circ}$ pattern was performed by utilizing a similar coordination strategy of the most stable $0^{\circ}$ pattern. Conclusion: The present current study suggests that the roles of distal and proximal joints differ in order to achieve various multi-joint coordination movements. This study provides information for use in gives an idea to development of rehabilitation or training programs for to persons with an impaired upper limb motor ability.

• Smart Structures and Systems
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• 제23권5호
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• pp.479-493
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• 2019

In this paper, the interaction between notch and micro pore under uniaxial compression has been performed experimentally and numerically. Firstly calibration of PFC2D was performed using Brazilian tensile strength, uniaxial tensile strength and biaxial tensile strength. Secondly uniaxial compression test consisting internal notch and micro pore was performed experimentally and numerically. 9 models consisting notch and micro pore were built, experimentally and numerically. Dimension of these models are 10 cm*1 cm*5 cm. the length of joint is 2 cm. the angularities of joint are $30^{\circ}$, $45^{\circ}$ and $60^{\circ}$. For each joint angularity, micro pore was situated 2 cm above the lower tip of the joint, 2 cm above the middle of the joint and 2 cm above the upper of the joint, separately. Dimension of numerical models are 5.4 cm*10.8 cm. The size of the cracks was 2 cm and its orientation was $30^{\circ}$, $45^{\circ}$ and $60^{\circ}$. Diameter of pore was 1cm which situated at the upper of the notch i.e., 2 cm above the upper notch tip, 2 cm above the middle of the notch and 2 cm above the lower of the notch tip. The results show that failure pattern was affected by notch orientation and pore position while uniaxial compressive strength is affected by failure pattern.

• 대한물리의학회지
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• 제11권4호
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• pp.27-32
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• 2016

PURPOSE: This study compared the immediate effect of a passive mobilization of upper cervical spine (Kaltenborn's joint mobilization) and an active upper cervical stretching (Olaf's Auto-stretching) on patients with neck pain and ROM. METHODS: Twenty-three subjects were randomized selected in the passive group (Kaltenborn's joint mobilization) included twelve subjects and the active group (Olaf's Auto-stretching) included eleven subjects. VAS (Visual Analogue Scale) was measured before and after neck rotation performance. DUALER IQ PRO (JTECH Medical, U.S.A.) was used to measure the neck ROM. Mean value of double measurement was used before performance and after performance. SPSS version 18 was used to compare values independent t-test and paired t-test were used to compare pain and ROM. RESULTS: There are significant difference in the pain and the ROM in both of two group (p<.05). But there are no significant difference pain and ROM between two groups. CONCLUSION: Both of the passive mobilization of upper cervical spine and the active upper cervical stretching are effected on symptom improvement of patients with neck pain reduction and ROM increasing. Especially active upper cervical stretching is more economical, because it has similar effects with the passive mobilization, help to maintain the treatment effect of therapist by themselves and can help to save medical expenses of patients.

• 근관절건강학회지
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• 제25권3호
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• pp.167-175
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• 2018

Purpose: The aim of this study was to test the effects of passive exercise on upper extremities muscle spasticity, finger edema, and depression for chronic stroke patients. Methods: A non-equivalent pretest-posttest design was employed for this study. The subjects were 30 elderly patients who were hospitalized to treat chronic stroke. 15 patients were assigned to the experimental and control groups respectively. Passive exercise for 20 minutes per day, five days a week for 8 weeks (total 40 times) was provided for the experimental group. Outcome measurements included manual spasticity test to measure upper extremities' muscle spasticity, the ring measurement method for finger edema and the Korean version of Short-form Geriatric Depression Scale (SGDS-K) for depression. Results: The upper extremities' muscle spasticity (Z=-2.52 p=.012) and the degree of depression (F=5.56, p=.006) in the experimental group were significantly reduced compared to those of the control group. But the degree of finger edema did not significantly differ between the two groups (F=1.46, p=.240). Conclusion: Passive exercise for upper extremities should be encouraged for elderly patients with chronic stroke to enhance the upper extremities' functional capacity as well as depression.

• 재활복지공학회논문지
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• 제7권1호
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• pp.21-27
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• 2013

수동 휠체어의 추진은 추진 동작의 낮은 효율로 인하여 사용자의 상지 관절에 고통과 부상까지 유발할 수 있다. 이에 따라 수동 휠체어 추진 중에 발생하는 상지 관절의 운동역학적 해석이 필요하다. 본 연구에서는 수동 휠체어 추진 중 상지 관절에 작용하는 토크를 구할 수 있는 2차원 역동역학 모델을 개발하였다. 개발한 모델은 시상면에서 상완, 하완, 손에 해당하는 3개의 체절로 상지를 구성하였고 몸통으로부터 3개의 체절을 회전조인트로 연결한 개방연쇄구조를 갖는다. 역동역학 해는 뉴턴-오일러 방법으로 구하였고 요구되는 입력자료는 실험을 통하여 획득하였다. 수동 휠체어 추진에 필요한 상지 거동의 운동학적 자료는 3차원 동작분석 시스템에서 추출하였고 역동역학 모델의 외력에 해당하는 운동역학적 자료는 브레이크식 다이나모미터에서 추출하였다. 역동역학 모델을 이용한 해석을 통하여 수동 휠체어 추진에 따른 상지 관절의 회전각과 관절 토크를 구하였다. 개발된 모델은 상지 관절에 관한 생체역학적 해석 도구이며 적은 노력으로 3차원 역동역학 모델로 확장하는 토대가 된다.