• 대한중풍순환신경학회지
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• 제14권1호
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• pp.8-14
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• 2013

■ Objectives The goal of this study is to find the correlation between the motor function and gait pattern of stroke patients. ■ Methods We measured Manual muscle test(MMT), Motricity index(MI) and Spatiotemporal gait parameters of admitted hemiplegic patients with stroke. The gait parameters were measured using a Treadmill gait system. ■ Results There is a significant correlation between motor function and spatiotemporal parameters such as step length, stride length, step time, stride time, total double support or cadence, in stroke patients. ■ Conclusion The better motor function of stroke was, the more gait improved.

• Journal of Power Electronics
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• 제16권2호
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• pp.610-620
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• 2016

The compound active clamp zero voltage soft switching (CACZVS) three-phase power factor correction (PFC) converter has many advantages, such as high efficiency, high power factor, bi-directional energy flow, and soft switching of all the switches. Triple closed-loop PI controllers are used for the three-phase power factor correction converter. The control objectives of the converter include a fast transient response, high accuracy, and unity power factor. There are six parameters of the controllers that need to be tuned in order to obtain multi-objective optimization. However, six of the parameters are mutually dependent for the objectives. This is beyond the scope of the traditional experience based PI parameters tuning method. In this paper, an improved chaotic particle swarm optimization (CPSO) method has been proposed to optimize the controller parameters. In the proposed method, multi-dimensional chaotic sequences generated by spatiotemporal chaos map are used as initial particles to get a better initial distribution and to avoid local minimums. Pareto optimal solutions are also used to avoid the weight selection difficulty of the multi-objectives. Simulation and experiment results show the effectiveness and superiority of the proposed method.

• Journal of the Optical Society of Korea
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• 제16권4호
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• pp.425-431
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• 2012

Utilizing the three-dimensional Snyder-Mitchell model with a PT-symmetric potential, we study the influence of PT symmetry on beam propagation in strongly nonlocal nonlinear media. The complex Coulomb potential is used as the PT-symmetric potential. A localized spatiotemporal accessible soliton solution of the model is obtained. Specific values of the modulation depth for different soliton parameters are discussed. Our results reveal that in these media the localized solitons can exist in various shapes, such as single-layer and multi-layer disk-shaped structures, as well as vortex-ring and necklace patterns.

• ETRI Journal
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• 제44권4호
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• pp.624-640
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• 2022

Taxi-demand forecasting and hotspot prediction can be critical in reducing response times and designing a cost effective online taxi-booking model. Taxi demand in a region can be predicted by considering the past demand accumulated in that region over a span of time. However, other covariates-like neighborhood influence, sociodemographic parameters, and point-of-interest data-may also influence the spatiotemporal variation of demand. To study the effects of these covariates, in this paper, we propose three models that consider different covariates in order to select a set of independent variables. These models predict taxi demand in spatial units for a given temporal resolution using linear and ensemble regression. We eventually combine the characteristics (covariates) of each of these models to propose a robust forecasting framework which we call the combined covariates model (CCM). Experimental results show that the CCM performs better than the other models proposed in this paper.

• 재활복지공학회논문지
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• 제10권4호
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• pp.251-257
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• 2016

소아균형검사(Pediatric Balance Scale)는 경증이나 중증의 운동손상을 지닌 학령기 아동에게 사용할 수 있는 균형검사도구이다. 본 연구의 목적은 경직성 양하지 뇌성마비 아동을 대상으로 소아균형검사와 시공간적 보행변수간의 상관관계를 알아보고자 하였다. 소아균형검사는 앉은 자세에서 일어나기, 선 자세에서 앉기, 의자에서 의자로 이동하기, 잡지 않고 서 있기, 한 다리로 서 있기, 제자리에서 $360^{\circ}$ 회전하기, 뒤돌아보기 등 총 14개 항목으로 구성하고, 시공간적 보행변수는 보행속도 및 보폭, 보거리, 보격, 분속수, 양하지 지지 시간을 포함한다. 모든 대상자들은 독립적으로 보행이 가능한 경직성 양하지 뇌성마비 아동이며, 숙련된 소아물리치료사에 의해 소아균형검사와 시공간적 보행변수를 측정하였다. 소아균형검사와 시공간적 보행변수 간의 상관관계를 분석하기 위해 피어슨 상관분석을 사용하였고, 통계학적 유의수준은 0.05로 설정하였다. 소아균형검사의 총점(r=.49~.58)과 세부항목 중 선 자세에서 앉기(r=.48~.60)와 선 자세에서 왼쪽/오른쪽 어깨 뒤로 돌아보기(r=.47~.53), 선 자세에서 바닥에 물건 집어 들기(r=.52~.69)는 보행속도와 보폭, 보거리, 분속수의 각 변수 사이에 모두 유의한 양의 상관관계를 보였으며, 소아균형검사의 대부분 항목이 양하지 지지 시간 간의 매우 높은 음의 상관관계(r=-.48~-.92)를 보여주고 있다. 이는 소아균형검사와 시공간적 보행변수는 높은 상관관계를 가진 것을 관찰 할 수 있었으며, 소아균형검사를 통해 뇌성마비 아동의 보행수준을 예견하는데 유용하게 적용될 것이다.

• 한국물환경학회지
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• 제38권1호
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• pp.1-9
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• 2022

The Yeongsan River, one of the four major rivers in Korea, shows the highest degree of water pollution compared to the other major rivers. The construction and opening of two weirs, Seungchon and Juksan, induced fluctuations in the hydrologic conditions and water quality of the river. To investigate the water quality changes caused by the opening of the weir in 2017, this study analyzed the water quality data using the non-parametric Wilcoxon signed-rank test and the three-dimensional spatiotemporal plots. The non-parametric statistical test results showed that the concentration of all parameters has increased after 2017 at a significance level of 0.05. For the parameters that showed the highest degree of change, chlorophyll-a and suspended solids, the median values have increased by more than 30% after weir opening. Visual analysis additionally showed the spatial changes in the Yeongsan River. Generally, the sites above the Seungchon weir showed higher pollution levels than those above the Juksan weir. In time series, visual analysis results also showed the trend of rising concentration for all water quality parameters, indicating that the opening of two weirs had a significant effect on the change in water quality of the Yeongsan River.

• 대한물리의학회지
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• 제11권1호
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• pp.61-69
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• 2016

PURPOSE: This study was conducted to investigate the effect of the virtual reality training (VRT) using 3-dimensional video gaming technology on spatiotemporal gait parameters in older adults. METHODS: The study participants were divided into two groups: the VRT group and the control group. Those in the VRT group were enrolled in a VRT, which was conducted for 60 min per day, two times a week, during the 6-week research. The Wii-Fit balance board game was used for the VRT intervention. The VRT consisted of 6 different types of games, namely, jogging, swordplay, ski jump, hula hoop, tennis, and step dance. A 3-dimensional TV was used for 3-dimensional display. Participants in both the groups received 3 sessions of fall prevention education, at the first, third, and fifth weeks. Their gait parameters were measured by using OptoGait. RESULTS: After 6 weeks of the VRT, the spatial gait parameters of the participants, that is stride length and step length, were significantly improved compared with those of the control group participants (p<0.05). The temporal gait parameters, such as velocity, cadence, stride time, and step time, also showed improvement after the completion of the VRT training (p<0.05). Both the temporal and spatial gait parameters of the VRT group participants showed improvement after 6 weeks of the program compared with those of the control group participants (p<0.05). CONCLUSION: The VRT using 3-dimensional video gaming technology might be beneficial for improving gait parameters to prevent falls among older adults.

• 대한한방내과학회지
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• 제41권2호
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• pp.194-203
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• 2020

Objectives: This study aimed to compare the gait patterns of cerebellar infarction patients with those of corticospinal tract stroke patients through a follow-up of patients with ataxic gait due to cerebellar infarction and corticospinal tract stroke. Methods: We investigated two cases of patients with cerebellar infarction and two cases each of acute or chronic corticospinal tract stroke who were hospitalized at Wonkwang University Gawangju Medical Center from September 1, 2017 to February 15, 2020 based on medical records and gait analyses. The spatiotemporal gait parameters of each patient were measured three times at 2-week intervals except those of the chronic corticospinal tract stroke patients, which were measured twice at a 1-month interval. Results: Spatiotemporal gait parameters, which include velocity, cadence, step length, stride length, and single support, were consistently increased in the cerebellar infarction patients in comparison to the corticospinal tract stroke patients. The stance phase was decreased in all the patients. Conclusions: The cerebellar infarction patients' gait spatiotemporal parameters were found to consistently improve. Moreover, gait analysis can be used to effectively measure improvement of ataxic gait.

• The Journal of Korean Physical Therapy
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• 제26권1호
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• pp.1-8
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• 2014

Purpose: The aim of the present study was to understand the relationship between gait symmetry and functional balance, walking performance in stroke patients and to makes recommendation regarding the most suitable measure for standardization of expression of spatiotemporal gait symmetry. Methods: 45 subjects with stroke (31 men, 14 women, $57.3{\pm}10.3$ years old) participated in this study. Gait symmetry was calculated by equations of symmetry ratio (SR) and symmetry criterion (SC) for stance time, swing time, single leg support time (SLST), step length, and stride length. Spatiotemporal parameters were measured respectively by walkway system ($GAITRite^{TM}$ system). Limit of stability (LOS) by using forceplate (Balance Performance Monitor) during voluntary weight displacement and Berg Balance Scale (BBS) were measured as functional balance and Timed Up and Go test (TUG) and Functional Ambulation Category (FAC) were assessed as functional walking. Results: SR in stance time and swing time was correlation with BBS, TUG and FAC (p<0.05). SR in SLST only with BBS (p<0.01), SR in step length only with FAC (p<0.05). SC in stance time was correlation with BBS and TUG (p<0.05). SC in swing time and SLST with BBS, TUG and FAC (p<0.01), SC in step length with TUG and FAC (p<0.01), SC in stride length with BBS and FAC (p<0.01). Conclusion: Gait symmetry in spatiotemporal gait parameters provides meaningful information about functional balance and walking performance in stroke subjects. Our analysis may support the recommendations of the symmetry criterion as equation for standardization of gait symmetry.

• 한국운동역학회지
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• 제31권2호
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• pp.95-103
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• 2021

Objective: The aim of this study was to investigate the differences in spatiotemporal gait performance, function, and pain of lower-extremity according to foot morphological characteristics. Method: This case-control study recruited 42 adults and they were classified into 3 groups according to foot morphology using navicular-drop test: pronated (≥ 10 mm), normal (5~9 mm), and supinated (≤ 4 mm) feet. Spatiotemporal gait analysis and questionnaires including Foot and Ankle Ability Measure activities of daily living / Sports, Western Ontario and McMasters Universities Osteoarthritis Index, Lower Extremity Functional Scale, International Physical Activity Questionnaire, and Tegner activity score were conducted. One-way analysis of variance was used for statistical analysis. Results: The pronated feet group showed longer loading response and double limb support in both feet and increased pre-swing phase in non-dominant feet. The supinated feet group demonstrated a longer swing phase in non-dominant feet and single limb support in dominant feet. However, there was no significant group difference in function and pain of knee joint and lower-extremity between groups. Conclusion: Our results indicated that abnormal spatiotemporal gait performance according to foot morphology. Although there was no difference in lower extremity dysfunction and pain according to the difference in foot morphology, they have the possibility of symptom occurs as a result of continuous participation in activities of daily living and sports. Therefore, individuals with pronated or supinated foot should be supplemented by utilizing an orthosis or training to restore normal gait performance.