• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.4
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• pp.725-728
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• 2008

An elbow orthosis with a pneumatic rubber actuator has been developed to assist and enhance upper limbs movements and has been examined for the effectiveness. The effectiveness of the elbow orthosis was examined by comparing muscular activities during alternate dumbbell curl motion wearing and not wearing the orthosis. The subjects participated in the experiment were younger adults in their twenties. The subjects were instructed to perform dumbbell curl motion in a sitting position wearing and not wearing orthosis in turn and a dynamometer was used to measure elbow joint torque outputs in an isokinetic mode. Orthosis was controlled using contractile muscle force that is measured from force sensor through cDAQ-9172 board. The air pressure of the pneumatic actuator was 0.3MPa the most suitable air pressure. For the analysis of muscular activities, Electromyography of the subjects was measured during alternate dumbbell curl motion. The experiment results showed that the muscular activities wearing the elbow orthosis were reduced. With this, we confirmed the effectiveness of the developed elbow orthosis.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.27 no.2
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• pp.37-43
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• 2021

Background: The purpose of this study is to compare and analysis the changes in strength and endurance of the knee extensor muscles after Anterior cruciate ligament reconstruction. Methods: Twelve male subjects with ligament injury were seated on Biodex and the hip joint was flexed at 110°, and torso, lower extremities, and legs were fixed using Velcro. The resistance device was placed at a point 3cm above the ankle, and measurements were taken before and a surgery at 60°/sec and 180°/sec when the knee was maximally extended. The postures ingeniously combine forward-bending poses countered with backward-bending ones. Results: There was no significant difference in the comparison of muscle strength of 60°/sec and 180°/sec before surgery. But there was a significant difference after surgery. There was significant difference in muscle endurance both before and after surgery. There was a significant difference in the pre- and post- operative comparison values of muscle strength and endurance in isokinetic movements at 60°/sec and 180°/sec during knee extension on the injured side. Conclusion: For cruciate ligament tears, Orthopedic reconstruction is recommended. Correct alignment of the knee ligament after surgery can enhance the strength and endurance of the quadriceps femoris during knee extension rejuvenated.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.1
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• pp.30-34
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• 2019

A newly proposed T-shape piezoelectric actuator, composed of piezoelectric benders, was designed and studied. This actuator has four legs, and can walk in both forward and backward directions. The piezoelectric actuator has a simple structure and can be easily fabricated. It consists of a piezoelectric bender and a joint. The piezoelectric bender is composed of carbon and ceramic materials. Therefore, there is an advantage in that it can be fabricated on a very small scale. Elliptical displacements of the piezoelectric actuators were analyzed by finite element analysis. Elliptical motion at the tip occurred at two voltages having a 90-degree phase difference. Based on the finite element analysis results, prototype actuators with maximum displacements were fabricated, and the characteristics of their movements were characterized.

• Phonetics and Speech Sciences
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• v.13 no.2
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• pp.1-7
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• 2021

Speech is a spatiotemporally coordinated structure of constriction actions at discrete articulators such as lips, tongue tip, tongue body, velum, and glottis. Like other human movements (e.g., reaching), each action as a linguistic task is completed by a synergy of involved basic elements (e.g., bone, muscle, neural system). This paper discusses how speech tasks are dynamically related to joints as one of the basic elements in terms of robotics of speech production. Further this introduction of robotics to speech sciences will hopefully deepen our understanding of how speech is produced and provide a solid foundation to developing a physical talking machine.

• Journal of the Korean Society of Clothing and Textiles
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• v.45 no.6
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• pp.965-977
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• 2021

The study aimed to analyze the functional differences in 3D virtual garment programs and compare body scan data with the corresponding 3D virtual models. We selected 3D virtual garment programs, formed virtual models in a representative size for high-school male cyclists, and analyzed them using the Design-X program. The results were as follows. In the 3D virtual garment programs, the anthropometric items for virtual model forming differed significantly from the standard anthropometric items suggested by Size Korea. Comparing the lower body scan data and virtual models formed by the 3D virtual garment programs, the biggest difference was in the shapes of the waist and hips, i.e., the flatness values of the waist and hips were different for each program in the cross-section view. In the lower body, a data-input-based program was needed for changing the exact measurement position of the waist circumference and hips' shape in detail. If a 3D virtual garment program provides functions for the virtual model's joint angle input and free motion transformation, it is expected to be widely used in the sportswear industry.

• Physical Therapy Korea
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• v.30 no.1
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• pp.78-85
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• 2023

Background: Despite fall prevention strategies suggested by researchers, falls are still a major health concern in older adults. Understanding factors that differentiate successful versus unsuccessful balance recovery may help improve the prevention strategies. Objects: The purpose of this review was to identify biomechanical factors that differentiate successful versus unsuccessful balance recovery in the event of a fall. Methods: The literature was searched through Google Scholar and PubMed. The following keywords were used: 'falls,' 'protective response,' 'protective strategy,' 'automated postural response,' 'slips,' 'trips,' 'stepping strategy,' 'muscle activity,' 'balance recovery,' 'successful balance recovery,' and 'failed balance recovery.' Results: A total of 64 articles were found and reviewed. Most of studies included in this review suggested that kinematics during a fall was important to recover balance successfully. To be successful, appropriate movements were required, which governed by several things depending on the direction and characteristics of the fall. Studies also suggested that lower limb muscle activity and joint moments were important for successful balance recovery. Other factors associated with successful balance recovery included fall direction, age, appropriate protective strategy, overall health, comorbidity, gait speed, sex and anticipation of the fall. Conclusion: This review discusses biomechanical factors related to successful versus unsuccessful balance recovery to help understand falls. Our review should help guide future research, or improve prevention strategies in the area of fall and injuries in older adults.

• Journal of the Society of Disaster Information
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• v.19 no.2
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• pp.326-333
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• 2023

Purpose: By analyzing how the Mali conflict has progressed over the past decade, the activities of terrorist groups in the Sahel are predicted, and their movements will have implications. Method: In addition to existing study, progress is identified through the media. Result: The Mali conflict has been sustained by the spread of ethnic conflict, Islamic extremism, and military coups. Conclusion: The influence of the international community is being weakened with the withdrawal of France and the intervention of Russia. This indicates that the Mali conflict could be prolonged.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.179-195
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• 2002

The purpose of this research is to provide a proper model by analyzing the sports biomechanical of physical movements on the basis of the two patterns(open-stance and cross-stance) at the ready-to-start pose. The subjects for this study are composed of five male handball players from P university and five female shooting players from S university. Three-way moving actions at start(right, left, and forward) are recorded with two high-speed video cameras and measured with two Force platforms and a EMG system. Three-dimensional action analyzer, GRF system, and Whole body reaction movement system are used to figure out the moving mechanisms at the start pose. The analytic results of the moving mechanism at the start pose were as follows. 1. Through examining the three-way moving actions at start, I have found the cross-stance pose is better for the moving speed of body weight balance than the open-stance one. 175 degree of knee joint angle at "take-off" and 172 degree of hip joint angle were best for the start pose. 2. The Support time and GRF data shows that the quickest center of gravity shift was occurred when cross-stanced male subjects started to move toward his lefthand side. The quickest male's average supporting time of left and right foot is 0.19${\pm}$0.07 sec., 0.26${\pm}$0.06sec. respectively. The supporting time difference between two feet is 0.07sec. 3. Through analyzing GRF of moving actions at start pose, I have concluded that more than 1550N are overloaded on one foot at the open-stance start, and the overloaded force may cause physical injury. However, at the cross-stance pose, The GRF are properly dispersed on both feet, and maximum 1350N are loaded on one foot.

• Korean Journal of Applied Biomechanics
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• v.16 no.1
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• pp.55-63
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• 2006

The purpose of this study is to prove the kinematical characteristics of Deff motion, the high bar performance, in terms of flying phases so that we can provide basic sources for improving gymnastic performance. To do this, we selected and analyzed the performance of two athletes who did Deff motion in the high bar competition of male artistic gymnastic in the 22nd Universiade 2003 Daegu. We drew the conclusions from the kinematical factors that were came out through analyzing three-dimensional cinematography of the athletes' movements, by using a high speed video camera. To make a successful performance, a performer releases the bar at a height of a high bar vertically and at a height of 82cm horizontally, and the flying performance should be made without moving forward, as maintaining the proper balance, in order to rise over 118cm high during the flying phase. When the performer is releasing the bar, an increase of the vertical speed in the center of the body and extension of a knee joint and a hip joint contribute to increasing a flying height. And when the moving body is twisted, leaning to left side is caused by the winding movement of a knee joint, which causes an unstable bar grasp. To grasp the bar stably, just before releasing the performer should gain propulsive force from twisting rotation through increasing the speed of shoulder rotation. And before the peak point, the performer should make sure of a body rotation distance over $164^{\circ}$ so that he or she can do an aerial rotary performance smoothly. When grasping the high bar, the center of the body should be above the bar and the angle of shoulder rotation should be maintained close to $540^{\circ}$ simultaneously. he high point performance(S1) has more speed on an ascending phase and less speed on a descending phase than the low point performance (S2). At the peak point, both the rotation angle of the body and that of the shoulder in high point performance are big as well. In conclusion, it is shown that a performer can make a jump toward the high bar easily with the body straight because the performer can hold the upper part of the body erect early in a descending phase.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.4
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• pp.257-267
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• 2023

Purpose. The purpose of the study was to fabricate a prototype robotic simulator for dental education, to test whether it could simulate mandibular movements, and to assess the possibility of the stimulator responding to stimuli during dental practice. Materials and methods. A virtual simulator model was developed based on segmentation of the hard tissues using cone-beam computed tomography (CBCT) data. The simulator frame was 3D printed using polylactic acid (PLA) material, and dentiforms and silicone face skin were also inserted. Servo actuators were used to control the movements of the simulator, and the simulator's response to dental stimuli was created by pressure and water level sensors. A water level test was performed to determine the specific threshold of the water level sensor. The mandibular movements and mandibular range of motion of the simulator were tested through computer simulation and the actual model. Results. The prototype robotic simulator consisted of an operational unit, an upper body with an electric device, a head with a temporomandibular joint (TMJ) and dentiforms. The TMJ of the simulator was capable of driving two degrees of freedom, implementing rotational and translational movements. In the water level test, the specific threshold of the water level sensor was 10.35 ml. The mandibular range of motion of the simulator was 50 mm in both computer simulation and the actual model. Conclusion. Although further advancements are still required to improve its efficiency and stability, the upper-body prototype simulator has the potential to be useful in dental practice education.