• Journal of Institute of Control, Robotics and Systems
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• v.15 no.12
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• pp.1216-1222
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• 2009

This article describes a simple method for generating the walking trajectory for the biped humanoid robot. The method used a simple inverted model instead of complex multi-mass model and a reasonable explanation for the model simplification is included. The problem of gait trajectory generation is to find the solution from the desired ZMP trajectory to CoG trajectory. This article presents the analytic solution for the bipedal gait generation on the bases of ZMP trajectory. The presented ZMP trajectory has Fourier series form, which has finite or infinite summation of sine and cosine functions, and ZMP trajectory can be designed by calculating the coefficients. From the designed ZMP trajectory, this article focuses on how to find the CoG trajectory with analytical way from the simplified inverted pendulum model. Time segmentation based approach is adopted for generating the trajectories. The coefficients of the function should be designed to be continuous between the segments, and the solution is found by calculating the coefficients with this connectivity conditions. This article also has the proof and the condition of solution existence.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.24 no.1
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• pp.39-46
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• 2018

Background: In most human lives, 80 percent have problems with the ankle and can be solved with a treatment that is objective in proper assessment. Discrepacts in the ankle are also associated with walking patterns and affect hip and knee joints. An evaluation of hip flexion and extensor muscles was performed to check the strength of hip joints after ankle sprain patients application of arthesis. Methods: In the hospital in Bucheon, 20 outpatients who visited the hospital for treatment with ankle sprain were tested with 10 male and 10 female patients. The criteria for selection of the study subjects were randomly divided into those with joint movement techniques applied to the ankle joints and those with conservative physical therapy. Results: In applying arthrography and preservation physical therapy to patients with ankle sprain, a difference in muscle strength between hip flexion and extensor was noted in post-evaluation comparisons. There were significant differences in the assessment of walking speed and walking time between the two counties in the gait analysis assessment (p<.05). Conclusion: Studies have shown that applying arthrography to people with ankle sprain has a greater therapeutic effect than using conservative physical therapy.

• The Korean Journal of Rehabilitation Nursing
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• v.20 no.1
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• pp.52-60
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• 2017

Purpose: This study aimed to evaluate the effects of lifestyle modifications on the constipation relief, the time required to see the effects, and the effective lifestyles for constipation in older adults admitted to a geriatric hospital. Methods: Nonequivalent control group pre-post test design was used. The subjects consisted of 25 elderly in the control group and 23 in the experimental group. Constipation was measured with symptoms of constipation, number of bowel movement and use of laxatives. Life style modification consisted of drinking water before breakfast, having a breakfast, scheduled toileting after breakfast and walking everyday for 3 weeks. Results: Symptoms of constipation (t=2.23, p=.030) and number of bowel movement per week (t=-2.55, p=.014) were significantly different between two groups after 3 weeks. Drinking water, scheduled toileting and walking might contribute to the results. Conclusion: Lifestyle modification was effective on constipation in older adults admitted to a geriatric hospital. However, the effects were produced after 3 weeks. Nevertheless, it is recommended that nurses continuously encourage older adults for drinking water, regular trying for bowel movement and walking to relieve constipation, since the lifestyle modification does not need any special education and skill.

• Physical Therapy Korea
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• v.13 no.4
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• pp.16-22
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• 2006

Falling is a serious problem associated with aging. Unintentional injury, which most often results from falling, is one of the leading causes of death in elderly people. The purpose of this study is to investigate the risk factors of falls and to compare characteristics of people who fall with that of non-fallers among the rural community-dwelling elderly of Korea. A sample of 201 people, living in the community, aged 60 years and over was taken from the members of a center for seniors located in Jecheon city. The mean age of the participants was 70.5 years of age. The participants are comprised of 151 women and 50 men. Eighty four of the 201 participants (41.8%) fell during the previous year. Twenty two of the fallers (26.2%) fell down more than two times. It was found that fallers had poorer eyesight, multiple chronic diseases and a more difficult time walking than non-fallers. In the logistic regression analysis of falls, only the difficulty of walking one kilometer (OR=2.4) and chronic diseases (OR=2.5) have shown an increased risk of falls. The risk of recurrent falls is, in addition, influenced by the difficulty of walking one kilometer. The result of our study shows that the impairment of mobility was the strongest risk factor of recurrent falling.

• Journal of Biomedical Engineering Research
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• v.15 no.2
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• pp.167-174
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• 1994

In this paper, a DSP and microcomputer-based EMG controlled functional electrical stimulation (FES) system, for restoring walking of paraplegics at the patients' own command, is presented. The above-lesion EMG is a time-varying nonstationary signal and its autoregressive (AR) parameters are identified by the nonstationary identification algorithm using a DSP chip. The identified AR parameters are used for the cloassification of the function and the control of the movement. The below-lesion response-EMG signal is used as a measure of muscle fatigue. This FES system is designed to measure muscle fatigue and control the stimulation intensity according to the amplitude of the response-EMG signal. While the automatic electrical intensity control is obtained by identifying the movement, the proposed FES system is suitable for the automatic control of paraplegic walking.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.7 no.3
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• pp.182-187
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• 2007

A fuzzy modeling method is proposed to build the dynamic model of a walking-beam reheating furnace from the recorded data. In the proposed method, the number of membership function on each variable is increased individually and the modeling accuracy is evaluated iteratively. When the modeling accuracy is satisfied, the membership functions on each variable are fixed and the structure of fuzzy model is determined. Because the training data is limited, in this process, as the number of membership function increase, it is highly possible that some rules are missing, i.e., no data in the training set corresponds to the consequent part of a missing rule. To complete the rulebase, the output of the model constructed at the previous step is used to generate the consequent part of the missing rules. Finally, in the real time application, a rolling update scheme to rulebase is introduced to compensate the change of system dynamics and fine tune the rulebase. The proposed method is verified by the application to the modeling of a reheating furnace.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.1
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• pp.329-343
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• 2019

In order to simulate the evacuation simulation of a ship during a sinking, the slope angle change of the ship must be reflected during the simulation. In this study, the passenger evacuation simulation is implemented by continuously applying the heeling angle change during sinking. To reflect crowd behavior, the human density and the congestion algorithm were developed in this research and the walking speed experiment in the special situation occurring in the inclined ship was conducted. Evacuation simulation was carried out by applying the experimental results and the change of the walking speed according to the heeling angle of the ship. In order to verify the evacuation simulation, test items suggested by International Maritime Organization (IMO) and SAFEGUARD Validation Data Set conducted on a large Ro-PAX ferry (SGVDS 1) which performed real evacuation trial in full-scale ships were performed and the results of simulation were analyzed. Based on hypothetical scenario of when a normal evacuation command is delivered to the passengers of MV SEWOL in time, we predicted and analyzed the evacuation process and the number of casualties.

• Journal of the Korean Society of Physical Medicine
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• v.7 no.4
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• pp.471-480
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• 2012

PURPOSE: The object of the present study is to investigate the effects of the insole supporting medial longitudinal arch while walking in spastic cerebral palsy with pes planus. METHODS: Ten spastic bilateral cerebral palsy children with pes planus participated in this study. The insole were custom-made for the individual child. Muscle activity was measured by surface EMGs attached on tibialis anterior (TA), gastrocnemius (GA), vastus medialis oblique (VMO), biceps femoris long head (BF). temporal-spatial parameters such as velocity, step length, stride length, stance time, toe angle were collected while the subjects walked on the GAITRite system. RESULTS: The results of the present study were summarized as follows: 1. Muscle activities in mean EMGs while walking: Left VMO, Right TA, Left BF and GA revealed significant reductions after applying insole. 2. Muscle activities in peak EMGs while walking: Left TA and BF demonstrated reductions significantly after applying insole. 3. There were improvements in temporal-spatial gait parameters with insole: velocity, both step length, Right stride length and Right toe angle were increased(p<.05). CONCLUSION: Therefore the current study demonstrated that insole supporting the medial longitudinal arch would be effective on gait of the spastic cerebral palsy with pes planus.

• Journal of Korean Society of Transportation
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• v.34 no.2
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• pp.168-179
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• 2016

This study describes an improved model for estimating pedestrian LOS (Level of Service) by utilizing the space occupied by pedestrians. The method introduced the concept of conflict along the bi-directional pedestrian flow which enables calculating conflict area and average travel time in walking. Especially, the method incorporates the idea of generalized density concept which can consider effective walking area and pedestrian flow rates that might vary during the analysis period. After establishing methodology, adjustments of pedestrian LOS criteria in term of walking space occupied by pedestrians were performed. As a result, walking-occupied space at capacity level is 0.68 and corresponding pedestrian flow rate was calculated as 80 persons/min/m, while different pedestrian-occupied spaces were ordered to classify LOS at the points where the gradient changes. Furthermore, the statistical verification of service levels has shown that there is significant difference among all LOS categories at 5% significance level.

• Physical Therapy Korea
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• v.15 no.1
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• pp.1-11
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• 2008

The purpose of this study was to assess the influence of two shoe size conditions on foot pressure, ground reaction force (GRF), and lower extremity muscle fatigue. Seven healthy men participated. They randomly performed walking and running in two different conditions: proper shoe size and 10 mm greater than proper shoe size. Peak foot pressure, and vertical, anterior and mediolateral force components were recorded with the Parotec system and Kisler force platform. To assess fatigue, the participants performed treadmill running for twenty-five minutes twice, each time wearing a different shoe size. Surface electromyography was used to confirm localized muscle fatigue using power spectral analysis of four muscles (tibialis anterior, gastrocnemius medialis, rectus femoris, and biceps femoris). The results were as follows: 1) In walking conditions, there was a significantly higher peak pressure in the 10 mm greater than proper shoe size insole sensor 1, 2, 14, and 18 (p<.05). 2) In running conditions, there was a significantly higher peak pressure in the 10 mm greater than proper shoe size insole sensor 5, 14, and 15 (p<.05). 3) In walking conditions, there was a significantly higher first maximal vertical GRF in the 10 mm greater than proper shoe size (p<.05). 4) In running conditions, no GRF components were significantly different between each shoe size condition (p>.05). 5) Muscle fatigue indexes of the tibialis anterior and rectus femoris were significantly increased in the 10 mm greater than proper shoe size condition. These results indicate that wearing shoes that are too large could further exacerbate the problems of increased foot pressure, vertical GRF, and muscle fatigue.