• International Journal of Aeronautical and Space Sciences
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• v.14 no.4
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• pp.379-386
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• 2013

The hemispherical resonator gyroscope is a type of vibratory gyroscope, which can measure angle or angular rate, based on its operating mode. This paper deals with the case when the hemispherical resonator gyroscope is operated in angle measurement mode. In angle measurement mode, the resonator pattern angle precesses, with respect to the external rotation input, by the principle of the Coriolis effect, so that the external rotation can be estimated, by measuring the amount of precession angle. However, this pattern angle drifts, due to the manufacturing error of the resonator. Since the drift effect causes degradation of the angle estimation performance of the resonator, the corresponding drift compensation control should be performed, to enhance the estimation performance. In this paper, a mathematical model of the hemispherical resonator gyro is first introduced. By using the mathematical model, a nonlinear observer for imperfection parameter estimation, and the corresponding compensation controller are designed to operate hemispherical resonator gyros, as angle measurement sensors.

• The Journal of Korean Medicine
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• v.44 no.1
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• pp.117-127
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• 2023

Objectives: The purpose of this study is to report the effect of hominis placenta pharmacopuncture and chuna manual therapy in patients with frozen shoulder. Methods: Frozen shoulder was treated with hominis placenta pharmacopuncture and chuna manual therapy, and the overall shoulder pain was measured by visual analog scale (VAS), and the range of motion (ROM) of shoulder movement was evaluated by measuring passive abduction and external rotation and active hand to shoulder blade test. Results: After the treatment, overall shoulder pain was reduced, and ROM of passive abduction and external rotation was increased. Conclusions: The above results show that hominis placenta pharmacopuncture and chuna manual therapy can be used as an effective treatment for frozen shoulder.

• Journal of Welding and Joining
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• v.18 no.5
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• pp.49-54
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• 2000

High speed rotating arc process, forming a flat bead surface with shallow penetration depth, can be applied to the automatic seam tracking, because the amplitude of current waveform increases at high rotation speed. Two high speed arc rotation mechanisms have been developed in Japan and Germany b rotating the electrode nozzle using an external motor, which are used prevalently for narrow gap and conventional seam welding. In this study, a new rotation mechanism was developed by using a hallow shaft motor designed to be installed in the electrode nozzle. By rotating the welding arc, the amplitude of current waveform increases remarkably since the self-regulation of arc is not fully performed. Experiments show that the arc sensor with high-speed rotation arc has improved its responsiveness and sensitivity.

• 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.

• 대한정형외과스포츠의학회:학술대회논문집
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• 2005.04a
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• pp.33-34
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• 2005

• PNF and Movement
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• v.18 no.2
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• pp.223-231
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• 2020

Purpose: The purpose of the study was to compare the effects of different methods of pelvic control on abdominal muscle activity and lumbopelvic rotation angle during active straight leg raising (ASLR) in patients with chronic back pain. Methods: The study participants were patients with low back pain (n = 30). They were instructed to perform ASLR with pelvic control, ASLR with pelvic belt, and ASLR only. Surface electromyography data were collected from the ipsilateral rectus femoris (IRF), ipsilateral internal oblique (IIO), contralateral external oblique (CEO), and ipsilateral rectus abdominal (IRA) muscles, and lumbopelvic rotation angle was measured using a motion analysis device. Results: Activation of all abdominal muscles was greater in the ASLR with pelvic control group than in the ASLR with pelvic belt and ASLR groups. The lumbopelvic rotation angle was lower in the ASLR with pelvic control group than in the other two groups (p < 0.05). Conclusion: These results suggest that ALSR with pelvic control is an effective means of increasing abdominal muscle activity and reducing unwanted lumbopelvic rotation in patients with chronic low back pain. Controlling the pelvis using the opposite leg is an effective form of ASLR exercise for patients with chronic low back pain.

• Physical Therapy Korea
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• v.24 no.4
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• pp.77-83
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• 2017

Background: Shoulder external rotation exercises are commonly used to improve the stabilizing ability of the infraspinatus. Although the side-lying wiper exercise (SWE) is the most effective shoulder external rotation exercise to maximize infraspinatus activity, the effect of adduction force on the infraspinatus and posterior deltoid has not been demonstrated. Objects: This study was conducted to investigate whether horizontal adduction force increases infraspinatus activity and decreases posterior deltoid activity. Methods: Twenty-eight healthy subjects (male: 21, female: 7; $age=23.5{\pm}1.8years$; $height=170.1{\pm}7.4cm$; $weight=69.4{\pm}9.6kg$) were recruited. Subjects were asked to perform the SWE under two conditions: (1) general SWE and (2) SWE with adduction force using pressure biofeedback. Surface electromyography (EMG) signals of the infraspinatus and posterior deltoid were recorded during SWE. Paired t-tests were used to compare the EMG activity of the infraspinatus and posterior deltoid between the two conditions. Results: Posterior deltoid muscle activity was significantly decreased following SWE with adduction force ($7.53{\pm}4.52%$) relative to general SWE ($11.68{\pm}8.42%$) (p<.05). However, there was no significant difference in the infraspinatus muscle activity between the SWE with adduction force ($28.33{\pm}12.16%$) and the general SWE ($26.54{\pm}13.69%$) (p>.05). Conclusion: Horizontal adduction force while performing SWE is effective at decreasing posterior deltoid activity.

• Journal of International Academy of Physical Therapy Research
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• v.2 no.1
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• pp.229-236
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• 2011

The purpose of this study was to comparatively analyze the active stability of shoulder joints according to the frequency of overhead motions, such as serving and spiking, engaged in by female professional volleyball athletes who play different positions, and to provide the results as the basic data for developing exercise programs to prevent shoulder joint injuries. The subjects of this study were 50 Korean female professional volleyball players and positions were as follows: left and right attackers, centers, setters, and liberos. The external rotation and internal rotation muscle strength and muscle strength ratios of the dominant and non-dominant arms of all subjects were measured using Biodex. The results of this study are as follows: Frist, no significant differences were found in the internal and external rotation muscle strength of the dominant and non-dominant arms between positions. Second, for the shoulder joint muscle strength ratio of the dominant arm, by position, the setter showed significantly greater stability compared to the other positions. Third, for the shoulder joint muscle strength ratio of the non-dominant arm, by position, no significant difference in stability between positions was found. Fourth, it was found that the dominant arm had significantly greater instability of the shoulder joint than the non-dominant arm for attackers and centers, but no significant difference was found for setters and liberos. This study comparatively analyzed the muscle strength ratios of the external/internal rotations and dominant/non-dominant arms, which can determine the stability of the shoulder joints between female professional volleyball playing positions that engage in jumps and spikes using only the dominant hand and positions that do not.

• Clinics in Shoulder and Elbow
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• v.4 no.2
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• pp.181-185
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• 2001

Purpose: We reviewed the bilateral anterior shoulder instability to evaluate the final outcomes and influencing factors that had effect on the final outcomes. Materials and Methods: Sixteen patients of the bilateral shoulder instability underwent the operative treatment and 15 patients could be followed up average 29 months. There were Bankart lesions in 28 cases and 46% retracted markedly onto the medial side of the glenoid neck. Capsular redundancy could be seen in 50%, but the generalized ligamentous laxity in only two patients. We performed open Bankart repair in 21 cases and arthroscopic repair in 9 cases. Inferior capsular shift was performed in 12 cases of 15 cases in patients who was shown the capular redundancy. Results: The average increment of the forward flexion was 4° postoperatively but the average decrement of the external rotation was 6° postoperatively. After the inferior capsular shift surgery, there were significantly the decrement in external rotation by 13° even though the forward flexion was at the same level comparing with preoperative motion. There were 13 cases(43%) in excellent result, 14 cases(47%) in good and 3 case(l0%) in poor. Rowe score improved from 53 to 87.3 postoperatively. Conclusion : Re-establishing a proper capsular tensioning in a bilateral anterior shoulder instability is critical to ultimate success because there was a redundant laxity in a half and majority of them had marked retraction of an anteroinferior glenohumeral ligament complex. Especially, it should be considered that an unexpected limitation of external rotation could be occurred in the inferior capsular shift surgery.

• Korean Journal of Applied Biomechanics
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• v.14 no.1
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• pp.133-144
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• 2004

The purpose of this study was to analyze the joint moment on lower extremity during a developpe devant. Data were collected by Kwon3D, KwonGRF program. Two professional modem female dancers were participated in this experiment. Subjects performed a developpe devant in meddle heights. On the axes of X, Y, Z, it was shown that the maximum joint moment was occurred in hip joint. The moments are plotted during developpe devant. The ankle muscles generate a plantar flexion moment and the knee muscles generate a flexion moment and The hip muscles generate a extension moment. So these muscles of joint muscles were known to play a key role in keeping the body balance while doing developpe devant. In addition adduction moment occurred at hip, knee, an ankle in the order of amount, we could assume from this data that him out motion started from the hip joint. There was small active turn out possible below the hip joint. A small amount of extra turn out could be obtained when standing because of flexion between the foot and floor, which could be used to give a passive external rotation force to the whole leg and this could produce a rotation between the knee and foot. This passive external rotation could produce very damaging results. Therefore, lower extremity joint muscles such as hip, knee, and ankle muscle should be trained to keep the body balance and prevent injury during developpe devant performance. And for the safe and perfect turn ort performance, hip joint abduction, the most important external rotating muscle for him out is needed to train and full stretching should be done in advance.