• 대한간호학회지
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• 제36권1호
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• pp.94-102
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• 2006

Purpose: The purpose of this study was to confirm the effects of a moderate and fast walking exercise program on middle-aged women's fatigue, serum lipids and immunoglobulins. Method: A non-equivalent control group pretest-posttest design was used for this study. The experiment was conducted for 10 weeks from May 17th to July 25th, 2004 with 44 middle-aged women, consisting of 16 for the moderate walking group, 15 for the fast walking group and 13 for the control group. Result: Walking exercise at both a moderate and fast speed was effective in middle-aged women in reducing fatigue and serum lipids. It was also revealed that extended periods of exercise was more effective in decreasing fatigue while for reducing serum lipid, high intensity exercise was more effective. In this study, serum immunoglobulins were reduced after moderate and fast walking exercise but its cause was not fully understood so further research is needed. Conclusion: This study helps us recognize the importance of regular exercise and promotes motivation to exercise for a healthy life among middle-aged women.

• 로봇학회논문지
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• 제8권2호
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• pp.92-103
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• 2013

Humanoid robot is the most intimate robot platform suitable for human interaction and services. Biped walking is its basic locomotion method, which is performed with combination of joint actuator's rotations in the lower extremity. The present work employs humanoid robot simulator and numerical optimization method to generate optimal joint trajectories for biped walking. The simulator is developed with Matlab based on the robot structure constructed with the Denavit-Hartenberg (DH) convention. Particle swarm optimization method minimizes the cost function for biped walking associated with performance index such as altitude trajectory of clearance foot and stability index concerning zero moment point (ZMP) trajectory. In this paper, instead of checking whether ZMP's position is inside the stable region or not, reference ZMP trajectory is approximately configured with feature points by which piece-wise linear trajectory can be drawn, and difference of reference ZMP and actual one at each sampling time is added to the cost function. The optimized joint trajectories realize three phases of stable gait including initial, periodic, and final steps. For validation of the proposed approach, a small-sized humanoid robot named DARwIn-OP is commanded to walk with the optimized joint trajectories, and the walking result is successful.

• 동력기계공학회지
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• 제21권5호
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• pp.41-47
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• 2017

To implement Argentina tango dancer-like walking of the humanoid robot, a new trajectory generation scheme based on particle swarm optimization of the blending polynomial is presented. Firstly, the characteristics of Argentina tango walking are derived from observation of tango dance. Secondly, these are reflected in walking pose conditions and cost functions of particle swarm optimization to determine the coefficients of blending polynomial. For the stability of biped walking, zero moment point and reference trajectory of swing foot are also included in cost function. Thirdly, after tango walking cycle is divided into 3 stages with 2 postures, optimal trajectories of ankles, knees and hip of lower body, which include 6 sagittal and 4 coronal angles, are derived in consequence of optimization. Finally, the feasibility of the proposed scheme is validated by simulating biped walking of humanoid robot with derived trajectories under the 3D Simscape environment.

• 대한물리의학회지
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• 제6권4호
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• pp.447-454
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• 2011

Purpose : The purpose of this study was to identify the effects of circuit class training on the performance of locomotor tasks in chronic stroke. Methods : The study included 45 patients with chronic stroke randomly divided into experimetal group and control group. Both groups participated in exercise classes three times a week for 8weeks. The experimental group had 10 workstation of circuit class designed to improve walking. The control group practiced fitness exercises by equipment in health center. Walking performance was assessed by measuring walking speed(timed 10-meter walk and TUG), GAITRite analysis and peak vertical ground reaction force through the affected foot during walking. Results : The experimental group demonstrated significant improvement(p<.05) compared with the control group in 10-meter walking and vertical ground reaction force after training. The experimental group showed significant improvements in the walking velocity and cadence by GAITRite system(p<.05). Conclusion : Task- oriented circuit class training leads to improvements in locomotor function in chronic stroke. Further studies are necessary to occur in usual environments to improve walking performance.

• 한국생산제조학회지
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• 제24권5호
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• pp.548-552
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• 2015

In this paper, we describe the quadruped walking-control algorithm of the complete full-size humanoid DARPA Robotics Challenge-HUBO (DRC-HUBO) robot. Although DRC-HUBO is a biped robot, we require a quadruped walking function using two legs and two arms to overcome uneven terrains in the DRC. We design a wave-type quadruped walking pattern as a feedforward control using several walking parameters, and we design zero moment point (ZMP) controllers to maintain stable walking using an inverted pendulum model and an observed-state feedback control scheme. In particular, we propose a switching algorithm for ZMP controllers using supporting value and weighting factors in order to maintain the ZMP control performance during foot switching. Finally, we verify the proposed algorithm by performing quadruped walking experiments using DRC-HUBO.

• 대한물리의학회지
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• 제17권3호
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• pp.51-58
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• 2022

PURPOSE: This study aimed to evaluate the correlation between executive function and gait evaluations for the elderly, and validate the obstacle gait evaluation as a cognitive impairment test tool. METHODS: This study was a cross-sectional design. 79 people aged 65 years or older were selected as subjects. The Korean version of the Mini-Mental State Examination (MMSE-KC) to evaluate overall cognitive function and the Trail Making Test (TMT) A, B to measure executive function were performed. The 4-meter walking speed test and the walking speed test while crossing over an obstacle were carried out to evaluate gait. The Spearman's correlation was used to measure the correlation between cognition and gait speed. RESULTS: There was no significant correlation between the 4 m gait speed and executive function( TMT-A (p = .056), TMT-B (p = .115)). However, there was a significant correlation between the 4 m gait speed and MMSE-KC (r = .277, p < .05). There was also a significant correlation between walking speed while crossing over an obstacle and all tests (MMSE-KC (r = .382, p < .01). TMT-A (r = -.327, p < .01), TMT-B (r = -.283, p < .05)). CONCLUSION: It was found that the gait speed while crossing over an obstacle was correlated with all cognitive function tests. Therefore, we suggest the use of the gait speed test while crossing over an obstacle rather than the simple gait test to diagnose cognitive decline.

• 한국전문물리치료학회지
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• 제9권1호
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• pp.43-51
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• 2002

Physiological Cost Index (PCI) of walking has been widely used to predict oxygen consumption in healthy subjects or patients. The purpose of this study was to evaluate the predictability of physiological cost index of walking for the amount of exercise and cardiac function. Walking exercise was conducted in 67 healthy children (age 4-12) with a self-selected comfortable walking speed on the level surface. Walking speed was calculated, and heart rate was measured before and immediately after the walking. PCI was calculated for statistical analysis. The results were as follows; 1) The walking speed tends to increase and PCI of walking tends to decrease with age. There was significant difference in walking speed and PCI of walking among three age groups (p<.05). The change of walking heart rate tends to decrease with age, however, there was no significant difference among three age groups. 2) Linear regression equation between walking speed and age was 'Y (walking speed) = 2.124X (age) + 48.286' ($R^2$=.337), (p=.00). 3) The walking heart rate tends to decrease with age. Linear regression equation between walking heart rate and age was 'Y (walking heart rate) = 143.346 - 2.63X (age)' ($R^2$=.3425), (p=.00). 4) The walking heart rate decreased as body surface area (BSA) increased. Linear regression equation between walking heart rate and BSA was 'Y (walking heart rate) = 149.830 - 27.115X (BSA)' ($R^2$=.3066), (p=.00). In conclusion, these equations and PCI could be useful to quantify the variation of energy expenditure of children with pathological gait when compared with age-matched healthy children.

• KIEAE Journal
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• 제8권1호
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• pp.105-110
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• 2008

Most high rise buildings have been constructed with steel structure systems with metal deck floors and concrete topping. Since the mass of the metal deck floor system is relatively thinner than that of the concrete floor system and due to the larger span compared to other floor systems, vibration serviceability problems are frequently occurred. Most of vibration problems are induced by the movement of humans. A walking load function was proposed for the better estimation of composite deck floor vibration based on site measurements in this paper.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.169-172
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• 2002

This paper is concerned with walking trajectory generation by applying the genetic algorithm. The walking trajectory is generated though three via-points and genetic algorithm is employed to find velocity and acceleration at each via-point. Also genetic algorithm is applied for balancing joint trajectory. Fitness function is used for minimizing the trajectory. As a result, new algorithm generated the smooth trajectory. The proposed algorithm is verified by the experiment of biped walking robot developed in our Control laboratory, and we compared the result with the previous walking algorithm. It showed that the new proposed algorithm generated the better walking trajectory.

• Structural Engineering and Mechanics
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• 제54권5호
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• pp.937-953
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• 2015

This paper investigates the load model for single footfall trace of human walking. A large amount of single person walking load tests were conducted using the three-dimensional gait analysis system. Based on the experimental data, Fourier series functions were adopted to model single footfall trace in three directions, i.e. along walking direction, direction perpendicular to the walking path and vertical direction. Function parameters such as trace duration time, number of Fourier series orders, dynamic load factors (DLFs) and phase angles were determined from the experimental records. Stochastic models were then suggested by treating walking rates, duration time and DLFs as independent random variables, whose probability density functions were obtained from experimental data. Simulation procedures using the stochastic models are presented with examples. The simulated single footfall traces are similar to the experimental records.