• Journal of Mechanical Science and Technology
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• v.19 no.6
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• pp.1253-1267
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• 2005

Misalignment can be an important problem in the integration of GPS/INS. Observability analysis of the alignment errors in the integration of low-grade inertial sensors and multi-antenna GPS is presented in this paper. A control-theoretic approach is adopted to study the observability of time-varying error dynamics models. The relationship between vehicle motions and the observability of the errors in the lever arm and relative attitude between GPS antenna array and IMU is given. It is shown that alignment errors can be made observable through maneuvering. The change of acceleration makes the components of the relative attitude error that are orthogonal to the direction of the acceleration change observable. The change of angular velocity makes the components of the lever arm error that are orthogonal to the direction of the angular velocity observable. The motion of constant angular velocity has no influence on the estimation of the lever arm.

• Journal of the Korean Society of Physical Medicine
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• v.19 no.1
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• pp.61-68
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• 2024

PURPOSE: This study aimed to provide basic clinical data by analyzing the impact of motion observation training and stretching exercises for improving postures on the neck alignment and balance of stroke patients to enable them to accurately recognize the correct exercise method. METHODS: After sampling 20 stroke patients who met the selection criteria, this study randomly assigned 10 people who were administered the stretching exercise with observation training to the experimental group and 10 who received only the stretching exercise intervention to the control group by drawing lots. Next, neck alignment and balance were pre-tested. All interventions were conducted for 30 minutes, 3 times a week for 4 weeks, and when all the interventions were completed after 4 weeks, neck alignment and balance were re-measured in the same way as the pre-test. RESULTS: The comparison of changes in neck alignment and balance within the experimental and control groups showed statistically significant differences in the craniovertebral angle, cranial rotation angle, and balance (p < .05) (p < .01). Between the groups, statistically significant differences were found in the craniovertebral angle, cranial rotation angle, and balance (p < .05) (p < .01). CONCLUSION: A statistically significant difference in neck alignment and balance was observed in the group that underwent stretching exercises combined with observational training and a statistically significant difference was found between the groups. Therefore, it is believed that observation training should be used in clinical practice to improve forward head posture and restore balance in stroke patients.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.4
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• pp.89-96
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• 2023

PURPOSE: To investigate the effects of the underwater Ai-Chi exercise on the joint range of motion, balance and posture. METHODS: Thirty-six college students (30 men, 6 women) were divided into a 'low physical activity' groups (Group I). and an 'appropriate physical activity' groups (Group II). The Ai-Chi underwater exercise was conducted three times a week for two weeks for both groups. A goniometer was used to measure the range of motion of the hip joint, and Y-Balance and the posture screen mobile were used to measure the stability of the lower extremities. RESULTS: An evaluation of the range of motion of the hip joint before and after the Ai-Chi exercise showed significant results in the low physical activity group. However, the flexural range showed a significant increase after exercise, but not significant result. In the comparison of the mean increase between groups, only the right hip joint showed a significant difference in both groups. Also, in the comparison of the Y balance test and posture screen test before and after exercise, both groups showed significant. CONCLUSION: The Ai-Chi underwater exercise helped improve the range of motion of the hip joint and the ability to balance. Also It helped improve posture alignment. In addition, although the increase in all physical activity groups lower than the appropriate physical activity groups was greater in all figures, the increase in the number of samples, the extension of the experimental period, and various variables could be obtained.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.2
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• pp.137-144
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• 2010

In general, spinal fusion surgery takes pressure off the pain induced nerves, by restoring the alignment of the spine. Therefore spinal fixation system is used to maintain the alignment of spine. In this study, a biomechanical study was performed comparing the SROM(Spinal Range Of Motion) of three types of system such as Rigid, Dynesys, and Fused system to analyze the behavior of spinal fixation system inserted in vertebra. Dynesys system, a flexible posterior stabilization system that provides an alternative to fusion, is designed to preserve inter-segmental kinematics and alleviate loading at the facet joints. In this study, SROM of inter-vertebra with spinal fixation system installed in the virtual vertebra from L4 to S1 is estimated. To compare with spinal fixation system, a simulation was performed by BRG. LifeMOD 2005.5.0 was used to create the human virtual model of spinal fixation system. Through this, each SROM of flexion, extension, lateral bending, and axial rotation of human virtual model was measured. The result demonstrates that the movement of Dynesys system was similar to normal condition through allowing the movement of lumbar.

• Korean Journal of Applied Biomechanics
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• v.26 no.3
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• pp.303-308
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• 2016

Objective: This study evaluated the vertical and horizontal forces in the frontal plane acting on a pedal due to the vertical alignment of the lower limbs. Method: Seven male subjects (age: $25.3{\pm} 0.8years$, height: $175.4{\pm}4.7cm$, weight: $74.7{\pm}14.2kg$, foot size: $262.9{\pm}7.6mm$) participated in two 2-minute cycle pedaling tests, with the same load and cadence (60 revolutions per minute) across all subjects. The subject's saddle height was determined by the height when the knee was at $25^{\circ}$ flexion when the pedal crank was at the 6 o'clock position (knee angle method). The horizontal force acting on the pedal, vertical force acting on the pedal in the frontal plane, ratio of the two forces, and knee range of motion in the frontal plane were calculated for four pedaling phases (phase 1: $330{\sim}30^{\circ}$, phase 2: $30{\sim}150^{\circ}$, phase 3: $150{\sim}210^{\circ}$, phase 4: $210{\sim}330^{\circ}$) and the complete pedaling cycle. Results: The range of motion of the knee in the frontal plane was decreased, and the ratio of vertical force to horizontal force and overall pedal force in the complete cycle were increased after vertical alignment. Conclusion: The ratio of vertical force to horizontal force in the frontal plane may be used as an injury prevention index of the lower limb.

• The Journal of Korean Physical Therapy
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• v.28 no.1
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• pp.33-38
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• 2016

Purpose: The aim of this study was to determine the effectiveness of pelvic tilt training using an inclinometer on joint position sense and postural alignment in individuals with stroke. Methods: Thirty-one subjects with chronic stroke were divided into two groups: the experimental group (16 subjects) and the control group (15 subjects). Subjects in both groups received neuro-developmental therapy five times per week. In addition, the patients in the experimental group also received pelvic tilt training using an inclinometer for 30 minutes, 3 times a week for 4 weeks. Maximal range of anterior, posterior pelvic tilt and joint position sense were used to evaluate pelvic tilt motion. Image analysis was performed for evaluation of postural alignment on in standing position. Results: Significant difference in Iimprovement of pre- and post-intervention of joint position sense was observed showed significant difference (p<0.05) in all groups. Experimental groups showed sSignificant differences in maximal range of posterior pelvic tilt in on the paretic side were observed in the experimental groups compared to with the control group (p<0.05). Conclusion: These findings suggest that pelvic tilt training using an inclinometer may help to improve range of pelvic tilt and joint position sense of stroke patients.

• Journal of Mechanical Science and Technology
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• v.17 no.1
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• pp.32-39
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• 2003

In this study we examined connections between vertebral motion and patterns of muscle activation during voluntary head tracking movements. A Rhesus (Maraca mulatta) monkey was trained to produce sinusoidal tracking movements of the head in the sagittal plane while seated. Radio-opaque markers were placed in the cervical vertebrae, and intramuscular patch electrodes were implanted to record from eight neck muscles. Videofluoroscopic images of cervical vertebral motion, and EMG (electromyographic) responses were simultaneously re-corded. Experimental results demonstrated that head and vertebrae moved synchronously and that motion occurred primarily at skull-C$_1$, C$\_$6/-C$\_$7/ and Csub 7/-C$_1$. Our findings illustrate that although the biomechanical constraints of each species may limit the number of solutions available, it is the task requirements that appear to govern CNS (central nervous system) selection of movement behaviors.

• Korean Journal of Applied Biomechanics
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• v.31 no.3
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• pp.168-175
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• 2021

Objective: To investigate the static and dynamic analysis of ankle joint complex between subjects with chronic ankle instability (CAI) and healthy controls. Method: A total of 38 subjects and CAI group (N=19) and healthy control (N=19) participated in this first study. Variables that were measured in this study were as follows: 1) Subtalar joint axis inclination and deviation 2) Rearfoot angle 3) Navicular drop test 4) Heel alignment view in alignment analysis. Intra Correlation Coefficient (ICC) is used for reliability. A secondary 17 subjects are recruited including 9 of CAI and healthy for gait analysis between group. Lower extremity sagittal, frontal, and transverse kinematics were measured. All data were analyzed to ensemble curve analysis. Results: 1) There were statistically significant differences in standing rearfoot, navicular drop, heel alignment view, subtalar joint (STJ) inclination and deviation. 2) Only in sagittal, meaningful difference is showed during walking in gait analysis. Conclusion: Morphological problem can affect ankle sprain in aspect of structure with no relation to compensation of neuromuscular.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.8
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• pp.7-12
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• 2010

When a vehicle is running, wheel is generating vertical and lateral force on the rail, in addition to load of vehicle, through a complicated set of motions. The derailment coefficient refers to the ratio of lateral force to vertical force(wheel load), and if the value exceeds a certain level, a wheel climbs or jumps over the rail. That's why the value is used as a criterion for running safety. Derailment coefficient of rolling stocks alters according to shape of rail track. I measured three-dimensional angular velocity and acceleration to use 3D Motion Tracker. Test result, derailment coefficient of rolling stocks and shape of rail track examined closely that have fixed relation. Specially, was proved that roll motion has the close coupling relation.

• Korean Journal of Applied Biomechanics
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• v.33 no.4
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• pp.128-136
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• 2023

Objective: The aim of this study was to investigate the effect of an 8-week closed kinetic chain typed Reformer and Chair Pilates exercise on static and dynamic lower limb alignment for healthy female adults. Method: Ten healthy young female adults without musculoskeletal injury history in last 6 months (Age: 29.3 ± 3.5 yrs., Height: 165 ± 3.4 cm, Body mass: 58.2 ± 5.4 kg) participated in this study. All participants asked to join the 8-week closed kinetic chain typed Reformer and Chair Pilates exercise, and the program was conducted for 60 minutes twice a week. Participants were asked to be measure a static Q-angle and performed free squat one week before and after the program. A 3-D motion analysis with 8 infrared cameras and 5 channels of EMG was executed in this study. The effectiveness of the training was evaluated by paired t-test, and the significance level was set at .05. Results: A significantly decreased in internal rotation angles was found at hip joint during free squat after the training. Also, significantly decreased in lateral rotation angles were found at knee and ankle joint during free squat after training. Finally, significantly decreased in muscle activations were found at adductor longus and peroneus longus during free squat after training. Conclusion: From results of our study, it is concluded that an 8-week closed kinetic chain typed Pilates exercise positively effect on lower limb alignment during dynamic movement.