• Physical Therapy Korea
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• v.26 no.1
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• pp.37-50
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• 2019

Background: Stroke is one of the most common diseases responsible for physical disabilities. In addition to their physical and occupational therapy, the self-exercise programs were developed for patients with hemiplegia to increase the intensity of their therapeutic exercise. Objects: The purpose of this study was to assess the effect of a customized self-exercise program (CSP) to walking function on improving stroke survivors' muscle strength and ambulation function. Method: To test the effect of the self-exercise program, the following tests were conducted: The functional ambulation category (FAC), Tinetti performance-oriented mobility assessment gait part (POMA-G), timed up and go (TUG), 10-meter walk, and 2-minute walk. The study included 161 consenting stroke patients (FAC score>1) from a randomized, screened sample of 217. The CSP group participated in a 30-minute CSP each day for 10 weeks in addition to completing a routine rehabilitation program. The control group received only a routine rehabilitation program. All the subjects were monitored by a therapist once a week and had to submit an exercise checklist at the end of each session. Result: The strength of the participants' upper and lower extremity muscles showed no significant differences between the CSP group and the control group. The FAC score and POMA-G also showed no significant differences. However, there were significant differences in the TUG, 10-meter walk test, and 2-minute walk test (p<.05). Conclusion: The findings of this study suggest that a CSP may improve gait-related function in stroke survivors.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.5 no.1
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• pp.25-33
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• 2001

Let G be a finite group with a probability measure. We investigate the random walks on G in terms of ergodicity of the associated skew product transformation.

• Bulletin of the Korean Mathematical Society
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• v.37 no.4
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• pp.649-657
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• 2000

The 2-step competition graph of D has the same vertex set as D and an edge between vertices x and y if and only if there exist (x, z)-walk of length 2 and (y, z)-walk of length 2 for some vertex z in D. The 2-step competition number of a graph G is the smallest number k such that G together with k isolated vertices is the 2-step competition graph of an acyclic digraph. Cho, et al. showed that the 2-step competition number of a path of length at least two is two. In this paper, we characterize all the minimal acyclic digraphs whose 2-step competition graphs are paths of length n with two isolated vertices and construct all such digraphs.

• Wind and Structures
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• v.11 no.4
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• pp.303-321
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• 2008

When first commissioned, the 1.6 km span 275kV Severn Crossing Conductor experienced large amplitude vibrations in certain wind conditions, but without ice or rain, leading to flashover between the conductor phases. Wind tunnel tests undertaken at the time identified a major factor was the lift generated in the critical Reynolds number range in skew winds. Despite this insight, and although a practical solution was found by wrapping the cable to change the aerodynamic profile, there remained some uncertainty as to the detailed excitation mechanism. Recent work to address the problem of dry inclined cable galloping on cable-stayed bridges has led to a generalised quasi-steady galloping formulation, including effects of the 3D geometry and changes in the static force coefficients in the critical Reynolds number range. This generalised formulation has been applied to the case of the Severn Crossing Conductor, using data of the static drag and lift coefficients on a section of the stranded cable, from the original wind tunnel tests. Time history analysis has then been used to calculate the amplitudes of steady state vibrations for comparison with the full scale observations. Good agreement has been obtained between the analysis and the site observations, giving increased confidence in the applicability of the generalised galloping formulation and providing insight into the mechanism of galloping of yawed and stranded cables. Application to other cable geometries is also discussed.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.2
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• pp.169-185
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• 2020

Purpose : This study aimed to conduct a comprehensive meta-analysis to evaluate the effect size for pulmonary function and gait capacity of treadmill exercise in stroke patients. In addition, we aimed to examine the current status of treadmill interventions and compare the effect sizes of treadmill training to provide evidence-based practice for future development and application. Methods : The meta-analysis study was conducted using research articles that applied treadmill exercise to stroke patients and were published between January 2005 and February 2020. For a systematic meta-analysis, we conducted a search using the PICOS framework and selected 25 domestic stroke- and treadmill-related studies. The Comprehensive Meta-Analysis program was used to calculate the effect sizes for lung function and gait capacity (6-minute walk test and 10 m walk test). As Cohen's d has a tendency to overestimate the effect size, we used Hedge's g to increase the accuracy in computing the effect size. Results : Based on the results of the meta-analysis, the total effect size of treadmill exercise was 0.535, which was statistically significant, with a medium effect size (p<0.05). The effects of treadmill exercise in stroke patients were divided into dependent variables, namely pulmonary function (0.372) and gait capacity (0.584). In addition, for gait capacity, the effect sizes were evaluated for both the 6-minute walk test (0.756) and the 10 m walk test (0.514). Conclusion : This study provides objective evidence of the effectiveness of treadmill-based gait training programs. We hope that the results of this study will help support the development and implementation of treadmill-based gait training in stroke patients. Treadmill training is expected to improve not only pulmonary function, but also the gait capacity of stroke patients. Long-term investigations on the effects of treadmill training in stroke patients are necessary.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.162.2-162
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• 2001

This paper presents the stability analysis of a biped robot IWR-III. We use a foot-rotation indicator(FRI) concept to reveal the degree of stability. The foot rotation can be a barometer of postural instability, which should be carefully treated in implementing a dynamically stable walk and avoided altogether in performing a statically stable walk. The conventionally mentioned zero moment point(ZMP) criterion may not be sufficient to express the stability of a biped robot. ZMP equation needs an assumption that the supporting foot is fixed firmly to the ground during the walking. Therefore, applying the FRI concept is more desirable when a biped robot is falling down ...

• Korean Journal of Cognitive Science
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• v.33 no.3
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• pp.155-168
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• 2022

In this paper, we introduce the SNUDM-G, a diffusion model analysis tool with improved computational speed. Although the diffusion model has been applied to explain various cognitive tasks, its use was limited due to computational difficulties. In particular, SNUDM(Koh et al., 2020), one of the diffusion model analysis tools, has a disadvantage in terms of processing speed because it sequentially generates 20,000 data when approximating the diffusion process. To overcome this limitation, we propose to use graphic processing units(GPU) in the process of approximating the diffusion process with a random walk process. Since 20,000 data can be generated in parallel using the graphic processing units, the estimation speed can be increased compared to generating data through sequential processing. As a result of analyzing the data of Experiment 1 by Ratcliff et al. (2004) and recovering the parameters with SNUDM-G using GPU and SNUDM using CPU, SNUDM-G estimated slightly higher values for certain parameters than SNUDM. However, in term of computational speed, SNUDM-G estimated the parameters much faster than SNUDM. This result shows that a more efficient diffusion model analysis for various cognitive tasks is possible using this tool and further suggests that the processing speed of various cognitive models can be improved by using graphic processing units in the future.

• Journal of Biosystems Engineering
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• v.41 no.1
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• pp.21-33
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• 2016

Purpose: In order to ensure that vegetable seedlings (with a soil block around their roots) are planted in an upright orientation after metering in a vegetable transplanter, they need to be dropped freely from a certain height. The walk-behind hand-tractor-powered machines do not have sufficient space to drop the seedlings from that height. In the present work, a hopper-type planting device was developed for the walk-behind hand-tractor-powered vegetable transplanter to ensure that the soil block seedlings are planted in an upright orientation. Methods: Various dimensionless terms were developed based on the dimensional analysis approach, and their effect on the planting of soil block seedlings in an upright orientation (planting efficiency) was studied. The optimum design dimensions of the hopper-type planting device were identified by the Taguchi method of optimization. Results: The ratio of the height of free fall to the sliding distance of the seedling on the surface of the hopper had the highest influence on planting efficiency. The planting efficiency was highest for plants with a height $15{\pm}2cm$. The plant handling Froude number, in interaction with the design of the hopper-type planting device, also significantly affected the planting efficiency. Of the hopper design factors, the length of the slide of the seedlings on the surface of the hopper was most important, and induced sufficient velocity and rotation to cause the seedling to fall in an upright orientation. An evaluation of the performance of the planting device under actual field conditions revealed that the planting efficiency of the developed planting device was more than 97.5%. Conclusions: As the seedlings were fed to the metering device manually, an increase in planting rate increased missed plantings. The planting device can be adopted for any vegetable transplanter in which the seedlings are allowed to drop freely from the metering device.

• PNF and Movement
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• v.13 no.1
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• pp.39-46
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• 2015

Purpose: The accelerometer is a tool for evaluating walking by the displacement of the center of mass (COM) in the body. Recently, smartphones have added an accelerometer app, and it can be used to evaluate outcomemanures in rehabilitation. The purpose of this study was to investigate the COM in the bodies of normal persons and stroke patients using this smartphone application while walking. Methods: Twenty normal persons and twenty-two stroke patients were recruited and had their COM measured using G-walk and the smartphone application, SMAP, during 10 m walking. Subjects repeated the 10 m of walking 3 times, and we used the SMAP, Accelerometer Monitor ver. 1.5.0, to evaluate COM during the walk. To measure the displacement of COM, we used the difference in value between the maximal angle and the minimum anterior-posterior (AP), mediolateral (ML), and rotational angles during the walk. Results: For the normal persons, there was significant correlation between the AP and AP of SMAP, and was also a significant correlation between rotational angle and the ML of SMAP. In the stroke patients, there was significant correlation between AP and ML, and the rotational angle of SMAP. Conclusion: Our research results suggest that if the SMAP system is reinforced in the case of patients who have a greater displacement of COM, it may be used as an evaluation tool during walking.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2187-2191
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• 2003

In this paper, a x/y-axis accelerometer is fabricated, using the SBM process on a <111> SOI wafer. This fabrication method solves the problem of the footing phenomenon in the conventional SOI process for improved manufacturability and performance. The roughened lower parts as well as the loose silicon fragments due to the footing phenomenon are removed by the alkaline lateral etching step of the SBM process. The fabricated accelerometer has a demodulated signal-to-noise ratio of 92 dB, when 40Hz, 5 g input acceleration is applied. The noise equivalent input acceleration resolution and bandwidth are $125.59\;{\mu}g$ and over 100 Hz, respectively. The acceleration random walk is $12.5\;{\mu}g/\sqrt{Hz}$. The output linearity is measured to be 1.2 % FSO(Full Scale Output) at 40 Hz, and the input range is over ${\pm}\;10g$.