• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.2
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• pp.75-83
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• 2023

In this paper, we present the analysis results on the vibration serviceability of a pedestrian bridge considering the effect of pedestrian moving mass inertia. Using dynamic finite element analysis, we considered different walking scenarios, including pedestrian density, walking speed, random walking, and synchronized walking, to analyze the acceleration response of a 40m long single-span bridge with a steel composite box cross section. We showed that the equivalent fixed mass analysis method did not significantly differ from the moving mass analysis in the random walk scenario and a wider frequency excitation band may be useful to consider when evaluating vibration serviceability in a random walk scenario.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.4
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• pp.47-54
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• 2020

PURPOSE: This study compared two different techniques of treadmill gait training, and evaluated the outcomes on gait and respiratory function in patients with hemiplegic stroke. METHODS: This was a single-blinded, randomized, controlled, comparative study, enrolling a total of 21 stroke patients in a rehabilitation hospital. Subjects were randomly assigned to either the treadmill walking training group with gradual speed increase (GSI group, n = 10), or treadmill walking training group with random speed changing (RSC group, n = 11). All participants performed 60 min of comprehensive rehabilitation therapy (5 × / week for 6 weeks). In additional, each group received either GSI or RSC treadmill walking training for 20 min (5 × / week for 6 weeks, total 30 sessions). Gait and respiratory function were measured before and after the 6-week training. RESULTS: Both groups showed significant improvements in the 10-m walking test, 6-minute walking test, timed up and go test, forced vital capacity (FVC), forced expiratory volume in 1 second, and maximal voluntary ventilation after training (p < .05). The GSI group showed a significantly greater increase in the FVC than the RSC group (+14.8 L vs. +12.5 L, p < .05). CONCLUSION: Both training methods can be effective for improving the walking and respiratory functions of stroke patients. However, our results indicate that treadmill walking training with gradual speed increase might be a more effective method for improving the respiratory function (FVC) than treadmill walking training with random speed changing.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.297-297
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• 2006

• Physical Therapy Rehabilitation Science
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• v.9 no.4
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• pp.222-229
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• 2020

Objective: The purpose of this study was to investigate the effect of treadmill exercise on the posture and walking speed of chronic stroke survivors with an ankle-foot orthosis. Design: Randomized controlled trial. Methods: Twenty-four chronic persons with chronic stroke admitted to Bobath Memorial Hospital in Seongnam city were divided into two groups by random blind method. Treadmill exercise with an elastic ankle-foot orthosis was performed in the experimental group and treadmill exercise was performed in the control group. The experiment was carried out for 6 weeks, and the experiment was carried out three times a week for 20 minutes per session. To measure the effect, static balance was measured using the MTD system before and after training, and the Berg Balance Scale (BBS) was used to measure functional balance. Results: There was a statistically significant difference between the 2 groups in the BBS measurement results for confirming the functional balance (p<0.05). Also, there was a significant difference between the 2 groups in single limb support time, step time and step length (p<0.05). Conclusions: In this study, it was found that treadmill exercise with an elastic ankle-foot orthosis in persons with chronic stroke was effective in maintaining functional balance, walking ability, step length, and step time. Therefore, it is necessary to use a flexible ankle-foot orthosis with proper treadmill exercise as a method of improving balance and walking speed of chronic stroke survivors.

• Research in Community and Public Health Nursing
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• v.18 no.1
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• pp.56-68
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• 2007

Purpose: The present study analyzed the contents of exercise programs for the elderly in Korean and foreign articles. Method: This study analyzed 27 Korean and 20 foreign exercise-related articles selected from Web DBs using keywords 'exercise', 'exercise program' and 'exercise effect'. The collected data were analyzed using SPSS 11.5 through descriptive statistics, $x^2$ test and Fisher's exact test. Results: In the description of population, random sampling and informed consents, foreign articles were higher than Korean articles. In research design, foreign articles randomized controlled trials (RCTs) higher than Korean articles. The contents of exercise programs in the Korean and foreign articles were aerobic, walking and stretching. On the effects of exercise programs in the Korean articles, walking showed the highest frequency in the physical strength as well as muscle strength, balance and flexibility. In the foreign articles, walking and stretching showed high frequency in physical strength. Conclusion: Contents significant in exercise programs for the elderly were walking and stretching. In addition, regular exercise had a positive effect on muscle strength, flexibility and balance in the elderly.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.3A
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• pp.184-194
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• 2005

One of the most important factors that decide the overall performance of RFID system is anti-collision algorithm. By enhancing the anti-collision algorithm, we can increase the number of RFID tags that can be processed in unit time. Two anti-collision algorithms are most widely prevailed: one is ALOHA-based protocol and the other is a binary tree walking method, but these are still under research. In this paper, we suggest an anti-collision algorithm named AAC(Address Allocating and Calling) using pre-distributed random address, which is much faster and more efficient than existing ones. Finally, we evaluate our scheme using mathematical analysis and computer simulation.

• Journal of Ocean Engineering and Technology
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• v.24 no.3
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• pp.21-30
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• 2010

This study presents a numerical simulation of sea water-exchange as a preliminary accessing tool of water quality in the protected shore behind a overtopped breakwater. The overtopped breakwater is taken into account for a safe swimming and beach protection. The overtopping rate is calculated by empirical models and the consequent currents, known as wave-induced currents, are calculated under the conditions of H.W.O.S.T and L.W.O.S.T. The rate of sea water exchange is used to evaluate the characteristics of sea water exchange and calculated through the simulation processes such as advective discharging through the outlets and random-walking diffusion of particles released within a basin. The numerical results show that the overtopped waves sufficiently improve the water exchange without healthless stagnation of contaminated mass and the consequent currents are not too strong for swimming.

• Korean Journal of Applied Biomechanics
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• v.30 no.4
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• pp.301-309
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• 2020

Objective: This study aimed to investigate the effect of white noise on dynamic balance in patients with stroke during walking. Method: Nineteen patients with chronic stroke (age: 61.2±9.8 years, height: 164.4±7.4 cm, weight: 61.1±9.4 kg, paretic side (R/L): 11/8, duration: 11.6±4.9 years) were included as study participants. Auditory stimulus used white noise, and all participants listened for 40 minutes mixing six types of natural sounds with random sounds. The dynamic balancing ability was evaluated while all participants walked before and after listening to white noise. The variables were the center of pressure (CoP), the center of mass (CoM), CoP-CoM inclined angle. Results: There is a significant increase in the antero-posterior (A-P) CoP range, A-P inclination angle, and gait speed on the paretic and non-paretic sides following white noise intervention (p<.05). Conclusion: Our findings confirmed the positive effect of using white noise as auditory stimulus through a more objective and quantitative assessment using CoP-CoM inclination angle as an evaluation indicator for assessing dynamic balance in patients with chronic stroke. The A-P and M-L inclination angle can be employed as a useful indicator for evaluating other exercise programs and intervention methods for functional enhancement of patients with chronic stroke in terms of their effects on dynamic balance and effectiveness.

• Korean Journal of Applied Biomechanics
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• v.27 no.1
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• pp.45-52
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• 2017

Objective: The aim of this study was to investigate the periodicity of the lower extremity joint flexion/extension angle to compare the local stability between young and elderly women during walking on a treadmill. Method: Eighteen young women (mean $age=21.2{\pm}1.6y$; mean $mass=57.1{\pm}6.1kg$; mean $height=1.61{\pm}0.04m$) and 18 elderly women (mean $age=66.4{\pm}1.2y$; mean $mass=55.4{\pm}8.3kg$; mean $height=1.56{\pm}0.04m$) participated in this study. Approximate entropy (ApEn) was used to determine the periodicity in the lower limb joint angles. Results: The ApEn values of the two groups were statistically greater in the surrogate data test than in the original time series data (p<.05). The periodicity of the hip and ankle flexion/extension angles decreased in the elderly women group compared with the young women group (p<.05). The periodicity of the lower extremity joint flexion/extension angle showed that the ankle joint increased dominatingly in both groups (p<.05); the hip joint decreased compared with the knee joint in the young women group; and the knee joint decreased compared with the hip joint in the elderly women group (p<.05). Conclusion: These results suggest that the lower extremity joint flexion/extension angles of the young and elderly women during walking contained random noises as well as biological signals. In addition, the differences in the periodicity in the lower extremity joint between the young and elderly women may provide some insight in predicting potential falls and be used as a characteristic indicator for determining local stability in elderly women during walking.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.4
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• pp.119-130
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• 2019

Purpose : The purpose of this study was to investigate the meta-analysis on the effects of action observation training on stroke patients' walking. Methods : Domestic databases (DBpia, KISS, NDSL, and RISS) were searched for studies that conducted randomized controlled trials (RCTs) associated with action observation training in adults after stroke. The search outcomes were items associated with the walking function. The 18 studies that were included in the study were analyzed using R meta-analysis. A random-effect model was used for the analysis of the effect size because of the significant heterogeneity among the studies. Sub-group and meta-regression analysis were also used. Egger's regression test was conducted to analyze the publishing bias. Cumulative meta-analysis and sensitivity analysis were also done to analyze a data error. Results : The mean effect size was 2.77. The sub-group analysis showed a statistical difference in the number of training sessions per week. No statistically significant difference was found in the meta-regression analysis. Publishing bias was found in the data, but the results of the trim-and-fill method showed that such bias did not affect the obtained data. Also, the cumulative meta-analysis and sensitivity analysis showed no data errors. Conclusion : The meta-analysis of the studies that conducted randomized clinical trials revealed that action observation training effectively improved walking of the chronic stroke patients.