• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.4
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• pp.450-456
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• 2014

Humanoid robot is the most suitable robot platform for effective human and robot interaction. However, the robot's complicated body structure containing more than twenty joint actuators makes it difficult to generate stable and elaborate postures using the conventional inverse kinematic method. This paper proposes an alternative approach to generate difficult postures of touching an object placed in front of the foot by the left or right hand with its torso bent forward in single support phase using the fast computational optimization method, particle swarm optimization. The simulated postures are also applied to a commercial humanoid robot platform, which validates the feasibility of the proposed approach.

• The Journal of Korean Physical Therapy
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• v.27 no.2
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• pp.112-117
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• 2015

Purpose: The purpose of this study was to examine the effects of a task-specific obstacle crossing rehabilitation program on functional gait ability in patients with cerebellar ataxia. Overall, we sought to provide ataxia-specific locomotor rehabilitation guidelines for use in clinical practice based on quantitative evidence using relevant analysis of gait kinematics including valid clinical tests. Methods: Patients with cerebellar disease (n=13) participated in obstacle crossing training focusing on maintenance of dynamic balance and posture, stable transferring of body weight, and production of coordinated limb movements for 8 weeks, 2 times per week, 90 minutes per session. Throughout the training of body weight transfer, the instructions emphasized conscious perception and control of the center of body stability, trunk and limb alignment, and stepping kinematics during the practice of each walking phase. Results: According to the results, compared with pre-training data, foot clearance, pre-&post-obstacle distance, delay time, and total obstacle crossing time were increased after intervention. In addition, body COM measures indicated that body sway and movement variability, therefore posture stability during obstacle crossing, showed improvement after training. Based on these results, body sway was reduced and stepping pattern became more consistent during obstacle crossing gait after participation in patients with cerebellar ataxia. Conclusion: Findings of this study suggest that task-relevant obstacle crossing training may have a beneficial effect on recovery of functional gait ability in patients with cerebellar disease.

• Korean Journal of Applied Biomechanics
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• v.21 no.3
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• pp.281-288
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• 2011

The purpose of this study was to analyze the difference in reaction patterns during the support phase after perturbation in gait according to different age. A total of 12 subjects participated; 5 elderly and 7 adults(control), to investigate the differences between normal and perturbed gait. The step length didn't change during normal and perturbed gait but was longer in the control group. There was no difference in the step width. When the right foot was perturbed, the control group's left foot speed was faster than the elderly group's which was to maintain stability. The elderly flexed both right and left knees more than the control group. After the perturbation, the elderly group had a larger trunk anterior flexion. With the larger flexion of both legs of the elderly group it shows that the lack of knee flexion strength is a factor, that could cause falling and so a prevention program should focus on strengthening the quadriceps. With the excessive trunk flexion after the perturbation by the elderly group observed, it is suggested that while walking everyday a good routine of walking with an upright posture should be developed.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.4
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• pp.350-356
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• 2004

This paper presents a farce manipulability analysis of multi-legged walking robots, which calculates force or acceleration workspace attainable from joint torque limits of each leg. Based on the observation that the kinematic structure of the multi-legged walking robots is basically the same as that of multiple cooperating robots, we derive the proposed method of analyzing the force manipulability of walking robot. The force acting on the object in multiple cooperating robot systems is taken as reaction force from ground to each robot foot in multi-legged walking robots, which is converted to the force of the body of walking robot by the nature of the reaction force. Note that each joint torque in multiple cooperating robot systems is transformed to the workspace of force or acceleration of the object manipulated by the robots in task space through the Jacobian matrix and grasp matrix. Assuming the torque limits are given in infinite norm-sense, the resultant dynamic manipulability is derived as a polytope. The validity of proposed method is verified by several examples, and the proposed method is believed to be useful for the optimal posture planning and gait planning of walking robots.

• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.7
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• pp.963-968
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• 1998

A study was conducted to investigate the effect of cooling hands of feet on human thermoregulation in the cold. Eight young (22$\pm$1 yr) and eight aged (69$\pm$4 yr) men volun-teered as subjects They stayed at 1$0^{\circ}C$ in the supine posture during the experiment which included hands or feet exposure to the air for 20 minutes. Hand Exposure (HE) and Foot Exposure (FE) were conducted in radomized order and the baseline was kept before HE and FE. Core temperatures, limb skin temperatures adn thermal sensations were measured. Obtained data were analyze using t-test and correlation. Rectal and esophageal tem-peratures increased in the young (YG) and in aged (AG). Change rate of esophageal temperature (Tes) was maintained higher during FE than HE while rectal temperature showed no differences between YG and AG, and between HE and FE. Hand and foot skintemperature in YG and AG decreased similarly during HE and Fe. Forearm skin temperature during HE decreased while leg skin temperature during FE showed no change HE and Fe. It was concluded that the lower cooling. Furthermore, the increase of Tes was greater in young men than aged men. It is also suggested that the wearing behavior can be differently modified between young and aged men.

• The Korean Journal of Community Living Science
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• v.22 no.3
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• pp.365-377
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• 2011

The dual purposes of this study were to investigate footwear worn by college students who have become spoilt for choice in apparel & shoes, and point out the problems of their shoe-wearing habbits. The survey was administered in October, 2010 to 600 college residents in Kwangju-Jeonnam area and the results are as follows. Firstly, the most frequently worn footware by males were sneakers, followed by dress shoes and oxford shoes. Females followed a similar trend with sneakers being the most frequently worn, followed by high heeled shoes, flat shoes, wedge high heeled shoes and chucker boots. Secondly, both male and female students thought that the most comfortable and favorable shoes for them were sneakers and the most uncomfortable ones were high-heeled shoes and sandals. They thought chucker boots were both fashionable and comfortable. Thirdly, the degree of unsatisfaction for shoes was relatively high and the influencing factors for unsatisfaction were uncomfortable soles, aches around the toes and a frontward leaning posture of the body, etc. Finally, 87% of the female subjects who had experience wearing high-heeled(over 7cm height) shoes showed a significant increase in foot disorders than those who had never worn high-heeled shoes. According to the results, it is necessary to educate proper selection and wearing of footwear in order to prevent foot disorders and maintain overall health of the body.

• The Journal of Korea CHUNA Manual Medicine
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• v.3 no.1
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• pp.55-64
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• 2002

Objectives : Acupuncture therapy is known as a effective method to CVA with paralysis. To make clear about effectiveness of acupuncture affecting to active and static postural adaptation for the patient with hemiparesis, we studied whether acupuncture changed ability of maintenance with one leg standing posture, and character of gait such as gait velocity, cadence, stride length, step length and base of support. Methods : This clinical study has been carried out with 10 cases of CVA patient with hemiparesis. We treated patients with acupuncture for 4 weeks, estimated each paralytic leg and well leg before 1st treatment and after last treatment, and compared the change of one leg with the other. To estimate the change of ability of static postural adaptation, we checked the time of duration with one leg standing posture. And about active postural adaptation, we used temporal distance gait analysis with Ink-Foot-Print method. Results and Conclusions : In static postural adaptation, paralytic leg significantly improved the duration with one leg posture. And In active postural adaptation with gait analysis, paralytic leg showed significant improvement in stride length and step length. Base of support and cadence were also significantly improved.

• The Journal of Korea Robotics Society
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• v.12 no.2
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• pp.132-143
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• 2017

While working in an industrial environment which requires extended periods of upright posture; workers tend to develop muscle fatigue due to the constant load on lower-limb muscles. In addition, when working while bending knees; muscle fatigue of lower back and hamstrings is increased due to the abnormal posture. This can lead to damage of muscles, induce musculoskeletal disorders, and reduce long-term working efficiency. Recent medical studies have shown that long-term working in an upright posture can induce musculoskeletal disorders such as foot fatigue, edema, pain and varicose veins. Likewise, medical and rehabilitation expenses have grown due to the increase in musculoskeletal conditions suffered by workers. For this problem, we aim to develop a device that can reduce the physical fatigue on the lower limbs by supporting the weight of workers during the extended periods of upright and bending postures in the industrial environments. In this paper, we have designed and manufactured a wearable weight support system; with a user intention algorithm that the users can maintain various postures. For validation of the developed system, we measured the muscle activity of the users wearing the system with EMG sensors.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.3
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• pp.760-764
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• 2005

This research was performed to investigate protective effect of Sophora Subprostrata fractions against focal ischemic brain damage after middle cerebral artery(MCA) occlusion. Rats were divided into six groups: MCA-occluded group(Control); each administered groups with Sophora Subprostrata total phase(Total), Sophora Subprostrata Aqueous phase (Aqueous), Sophora Subprostrata BuOH phase(BuOH), and Sophora Subprostrata Alkaloid phase(Alkaloid) after MCA-occlusion; sham-operated group(Sham). The right MCA was occluded by A poly-L-lysine coated 4-0 nylon suture thread through the internal carotid artery permanently. Sophora Subprostrata and fractions were administered orally(5mg/ml) for 7 days after MCA-occlusion. The behavior of ischemic rats were examined at 24 hours, 3, 5 and 7 days after MCA-occlusion from the views of 4 different aspects: posture & balance tests(4 subtests), reflex tests(6 subtests), muscle-tone tests(3 subtests), and foot-fault test. The results showed that 1) in muscle tone test, Sophora Subprostrata total phase only increased reduced muscle tone function from 3 to 7 days, 2) in reflex test, Sophora Subprostrata total and Aqueous phase increased fast recovery from 24 hours and 3 days, 3) in posture & balance test, Sophora Subprostrata total and Aqueous phase increased fast recovery from 24 hours, and Sophora Subprostrata BuOH and Alkaloid phase increased posture & balance function from 3 days, but 4) in motor function test, Sophora Subprostrata did not show effective recovery compared with control group. In conclusion, Sophora Subprostrata has protective effects against brain damage at the early stage of focal cerebral ischemia. Sophora Subprostrata total and Aqueous phase produced more pronounced protective effect against focal ischemic brain damage.

• Journal of the Ergonomics Society of Korea
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• v.32 no.4
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• pp.389-396
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• 2013

Objective: The ride qualities of the six passenger cars were evaluated in 4 subjects on the highway and uneven road. The relation between vibration with driving velocity and driving posture were also investigated separately. Background: Ride comfort plays an important role in the vehicle design. Vibration is the one of the principal components associated with ride comfort. Method: The acceleration of the foot, hip and back were measured using B&K accelerometers in this study. The velocity of the passenger cars was maintained at a constant speed of 80km/h on the highway and 40km/h on the uneven road. For evaluating the effects of driving velocity and driving posture on vehicle's vibration level, separate experiments were performed on the highway with 5 different vehicle speeds and 5 different backrest angles, respectively. Results: The overall ride value of the luxury car showed the best result while the smaller car showed the worst value on the highway. On the uneven road the overall ride value level was increased 75~98%. All the vehicles had the SEAT value less than 1. Faster the velocity lowers the SEAT value. The ride quality in terms of vibration gets worst when the backrest angle increased. Conclusion: The smaller car had a first mode at the higher frequency and showed higher vibration level. SEAT value was mostly affected by the seat property not by vehicle. We ranked the luxury car seat had a best vibration reduction quality than others based on SEAT values. When the driving velocity increased, the overall ride values were increased proportionally and the SEAT values were somewhat decreased. Application: Evaluation of whole-body vibration in the passenger car.