• Proceedings of the KSME Conference
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• 2007.05a
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• pp.786-791
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• 2007

Statistical differences between men and women are investigated for a total of eleven joint motions during level walking. Human locomotion which exhibits nonlinear dynamical behaviors is quantified by the chaos analysis. Time series of joint motions was obtained from gait experiments with ten young males and ten young females. Body motions were captured using eight video cameras, and the corresponding angular displacements of the neck and the upper body and lower extremity were computed by motion analysis software. The maximal Lyapunov exponents for eleven joints were calculated from attractors constructed and then were analyzed statistically by one-way ANOVA test to find any difference between the genders. This study shows that sexual differences in joint motions were statistically significant at the shoulder, knee and hip joints.

• Korean Journal of Applied Biomechanics
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• v.17 no.1
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• pp.9-16
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• 2007

Cutting movements frequently occur in sports and influence much Lower Extremity injuries. The purpose of this study was to compare joint motion of lower extremities to cutting angles and running velocities. Seven male subjects performed cutting movements to three angles($0^{\circ}$, $30^{\circ}$, $60^{\circ}$). Subjects were instructed to run five meters at a speed of 2.5m/s and 4.5m/s before contacting their right foot on the force plate and then change direction to the left. The Peak hip, knee and ankle joint kinematics were influenced according to the running velocities and cutting angles. In conclusion, Fast running velocity and cutting angle will may influence on the lower extremity joint instability on real game situation.

• Science of Emotion and Sensibility
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• v.24 no.4
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• pp.129-138
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• 2021

This study aimed to determine the effects of the shape and attachment position of stretchable textile sensors coated with carbon nanotube on their performance when used to measure children's joint movements. Moreover, the child-safe requirements for fabric motion sensors are established. The child participants were advised to wear integrated clothing equipped with the sensors of various shapes (rectangular and boat-shaped) and attachment positions (at the knee and elbow joints or 4 cm below the joints). The voltage change induced by the elongation and contraction of the fabric sensors was determined for arm and leg flexion-extension motions at 60 deg/s (three measurements of 10 repeats each for 60°and 90°angles, for a total of 60 repetitions). Their dependability was determined by comparing the fabric motion sensors to the associated acceleration sensors. The experimental results indicate that the rectangular-shaped sensor affixed 4 cm below the joint is the most effective fabric motion sensor for measuring children's arm and leg motions. In this study, we designed a textile sensor capable of tracking children's joint motion and analyzed the sensor shape and attachment position on motion sensing clothing. We demonstrated that flexible fabric sensors integrated into garments may be used to detect the joint motions of the human body.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.1118-1133
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• 2017

Computer vision-based human activity recognition (HAR) has become very famous these days due to its applications in various fields such as smart home healthcare for elderly people. A video-based activity recognition system basically has many goals such as to react based on people's behavior that allows the systems to proactively assist them with their tasks. A novel approach is proposed in this work for depth video based human activity recognition using joint-based motion features of depth body shapes and Deep Belief Network (DBN). From depth video, different body parts of human activities are segmented first by means of a trained random forest. The motion features representing the magnitude and direction of each joint in next frame are extracted. Finally, the features are applied for training a DBN to be used for recognition later. The proposed HAR approach showed superior performance over conventional approaches on private and public datasets, indicating a prominent approach for practical applications in smartly controlled environments.

• Journal of the Ergonomics Society of Korea
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• v.15 no.1
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• pp.39-52
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• 1996

This paper measured the range of arm joint motion for Korean 54 males in twenties. The range of the arm joint motion of the subjects was measured directly using Goniometer and protractor. The number of the static and the dynamic anthropometric variables are seven and thirteen, respectively. The anthropometric data are analyzed by basic statistical analysis (four group), correlation analysis and regression analysis using commercial SAS program. The results of analysis are compared with American students anthropometric data by Laubach(1978). Thin subjects have larger movement angle as wrist flexion, wrist abduction, elbow flexion, and elbow wupination and have smaller as wrist adduction and shoulder flexion. Fat subjects have larger movement angle as shoulder flexion and are smaller wrist abduction, elbow flexion, pronation, shoulder extension, shoulder adduction, shoulder abduction, and shoulder medial rotation Korean are more flexible than American in wrist and ranges of elbow flexion and elbow rotation. The shoulder movement is similar to that of American, but shoulder flexion is less flexible.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.5
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• pp.551-561
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• 1992

A neural optimization network and fuzzy rules are proposed to control the redundant robot manipulators in an environment with obstacle. A neural optimization network is employed to solve the optimization problem for resolved motion control of redundant robot manipulators in an environment with obstacle. The fuzzy rules are proposed to determine the weights of neural optimization networks to avoid the collision between robot manipulators and obstacle. The inputs of fuzzy rules are the resultant distance and change of the distance and sum of the changes by differential motion of each joint. And the output of fuzzy rules is defined as the capability of collision avoidance of joint differential motion. The weightings of neural optimization networks are adjusted according to the capability of collision aboidance of each joint. To show the validities of the proposed method, computer simulation results are illustrated for the redundant robot of the planar type with three degrees of freedom.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.3
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• pp.161-172
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• 2007

This article suggests an inverse kinematics analysis of a two degree of freedom spatial parallel motion simulator and design methodology of the robust PID controller. The parallel motion simulator consists of a fixed base and a moving frame connected by two serial chains, with each serial chain containing one revolute joint and two passive spherical joint. First, an inverse kinematics problems are solved in order to find the joint variable necessary to bring the end effector to track the desired trajectory. Second, an inverse optimal PID controller is proposed to track trajectories in the face of uncertainty. And the $H_{\infty}$ optimality and robust stability of the closed-loop system is acquired through the PID controller. Finally numerical results show the effectiveness of the PID controller that is designed by square/linear tuning laws.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.643-644
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• 2006

The purpose of this study is to experimentally analyze swing motion with soft golf clubs and compare with that with normal golf clubs. Soft golf is newly devised recreational sport based on golf but focus on the playability for the elderly. The subject fur the experiment performed swing motion using a normal golf club and a soft golf club in turn. The swing motion of the subjects was tracked using an opto-electric three-dimensional motion analysis system. The results were compared against those obtained with a normal golf club. The range of motion was analyzed along with top head speed for two cases. It was found that higher club head speed could be achieved with reduced range of motion at lumbar joint using soft golf club when compared against the swing using regular club. The lower range of motion fur lumbar bending means reduced risk of injury at the joint. So, it is projected that we can reduce the risk of injury with soft golf while maintaining the club head speed.

• Journal of Korean Foot and Ankle Society
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• v.12 no.1
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• pp.86-92
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• 2008

Purpose: To evaluate the safety and prognostic factors of intramedullary nailing of distal tibia fractures in terms of function and symptoms of the ankle joint. Materials and Methods: We retrospectively analyzed 22 distal tibial fractures with intramedullary nailing. The mean duration of follow-up was 43 months. We reviewed medical records to describe each case. We measured radiographic parameters such as fracture configuration, arthritic change of the ankle joint and status of reduction. We also assessed clinical results by AOFAS ankle hind foot scoring system, degree of pain by VAS and range of motion to find out prognostic factors for functional result of the ankle joint. Results: Bone healing was obtained in all cases without any wound complications. Mean AOFAS ankle score was 94. There were 4 cases with mild (VAS<3/10) ankle pain and 2 cases with mild limitation of ankle motion. The comminution of fracture had a significant relationship with delayed angular deformity of ankle joint (p=0.032). There was no other significant parameter affecting ankle joint function except the location of nail-end. Conclusion: Intramedullary nailing in distal tibia fracture is a safe and effective procedure. But further study may need to evaluate the relationship between the position of nail-end and the function of ankle joint.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.6
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• pp.670-677
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• 2011

This study is to estimate the joint torques without torque sensor using the EMG (Electromyogram) signal of agonist/antagonist muscle with Neural Network Back Propagation Algorithm during the elbow motion. Command Signal can be guessed by EMG signal. But it cannot calculate the joint torque. There are many kinds of field utilizing Back Propagation Learning Method. It is generally used as a virtual sensor estimated physical information in the system functioning through the sensor. In this study applied the algorithm to obtain the virtual senor values estimated joint torque. During various elbow movement (Biceps isometric contraction, Biceps/Triceps Concentric Contraction (isotonic), Biceps/Triceps Concentric Contraction/Eccentric Contraction (isokinetic)), exact joint torque was measured by KINCOM equipment. It is input to the (BP)algorithm with EMG signal simultaneously and have trained in a variety of situations. As a result, Only using the EMG sensor, this study distinguished a variety of elbow motion and verified a virtual torque value which is approximately(about 90%) the same as joint torque measured by KINCOM equipment.