• PNF and Movement
• /
• 제22권1호
• /
• pp.113-128
• /
• 2024

Purpose: This study aimed to investigate the effects of eccentric training applied to the calf muscles on muscle tone, muscle strength, and gait variables in patients with chronic stroke. Methods: Twenty-two participants were divided into experimental (n=12; eccentric training) and control (n=10; static stretching and stretching board) groups. The participants completed 30-minute physical therapy sessions five times a week for three weeks. Calf muscle tone, muscle strength, and gait variables were measured using MyotonPRO, a hand-held dynamometer, and Optogait, respectively, before and after each intervention. Results: Two-way analysis of variance (ANOVA) indicated a significant interaction effect between measurement points and groups in frequency, stiffness, and decrement of the lateral gastrocnemius, medial gastrocnemius, and soleus muscles (p<.05). Paired t-tests showed that the experimental group exhibited significantly decreased frequency and stiffness scores for the lateral gastrocnemius, medial gastrocnemius, and soleus muscles (p<.05), as well as significantly increased decrement and muscle strength scores, gait speed, step length, and stride length (p<.05). Conclusion: The application of eccentric training to the calf effectively reduced muscle tone, increased muscle strength, and improved the gait speed, step length, and stride length of patients with chronic stroke.

• 대한물리의학회지
• /
• 제6권4호
• /
• pp.369-379
• /
• 2011

Purpose : The purpose of this study is to compare the initial effect of nerve mobilization (NM), static stretching (SS), and contract-relax (CR) techniques to find the best method in improving hamstring flexibility and gait function in patients with hemiplegia. Methods : Eleven patients with hemiplegia were included in this study. Passive knee extension (PKE) range of motion and the sit and reach (SR) test were used to measure hamstring flexibility, while timed up and go (TUG) and the 10m walking (10MW) test were used to measure the subject's gait. Measurements on each test were assessed prior to the experiment, immediately following the experiment, and 30 minutes after the experiment. Analysis of the results utilized a repeated measures analysis of variance to examine hamstring flexibility and the difference in walking ability. Results : The results suggest significant increases in NM, SS, and CR techniques as they relate to hamstring flexibility (p<.05) following (both immediate and 30 minutes post experiment) PKE range of motion and the SR test, but post-hoc showed no significant difference between the three techniques (p>.05). Additionally, the results suggest significant increases in NM, SS, and CR techniques as they relate to gait function (p<.05) following the TUG test, but found no significant difference in the 10MW test (p>.05). Post-hoc analysis between the three techniques suggests that only the NM technique significantly changed gait function. The time of TUG and 10MW test showed no significant difference between the three techniques before an experiment, just after an experiment, and 30 minutes following the experiment according to the measurement points in time (p>.05). Conclusion : This study suggests NM, SS, and CR techniques immediately improve hamstring length and flexibility while improving gait function in patients with hemiplegia.

• Smart Structures and Systems
• /
• 제15권1호
• /
• pp.99-117
• /
• 2015

The Stonecutters Bridge (SCB) in Hong Kong is the third-longest cable-stayed bridge in the world with a main span stretching 1,018 m between two 298 m high single-leg tapering composite towers. A Wind and Structural Health Monitoring System (WASHMS) is being implemented on SCB by the Highways Department of The Hong Kong SAR Government, and the SCB-WASHMS is composed of more than 1,300 sensors in 15 types. In order to establish a linkage between structural health monitoring and maintenance management, a Structural Health Rating System (SHRS) with relevant rating tools and indices is devised. On the basis of a 3D space frame finite element model (FEM) of SCB and model updating, this paper presents the development of an SHR-oriented 3D multi-scale FEM for the purpose of load-resistance analysis and damage evaluation in structural element level, including modeling, refinement and validation of the multi-scale FEM. The refined 3D structural segments at deck and towers are established in critical segment positions corresponding to maximum cable forces. The components in the critical segment region are modeled as a full 3D FEM and fitted into the 3D space frame FEM. The boundary conditions between beam and shell elements are performed conforming to equivalent stiffness, effective mass and compatibility of deformation. The 3D multi-scale FEM is verified by the in-situ measured dynamic characteristics and static response. A good agreement between the FEM and measurement results indicates that the 3D multi-scale FEM is precise and efficient for WASHMS and SHRS of SCB. In addition, stress distribution and concentration of the critical segments in the 3D multi-scale FEM under temperature loads, static wind loads and equivalent seismic loads are investigated. Stress concentration elements under equivalent seismic loads exist in the anchor zone in steel/concrete beam and the anchor plate edge in steel anchor box of the towers.

• Geomechanics and Engineering
• /
• 제34권3호
• /
• pp.233-250
• /
• 2023

This paper investigates the flexural analysis of isotropic, transversely isotropic, and laminated composite plates using a new higher-order normal and shear deformation theory. In the present theory, only five unknown functions are involved compared to six or more unknowns used in the other similar theories. The developed theory does not need a shear correction factor. It can satisfy the zero traction boundary conditions on the top and the bottom surfaces of the plate as well as account for sufficient distribution of the transverse shear strains. The thickness stretching effect is considered in the computation. A simply supported was considered on all edges of the plate. The plate is subjected to uniform and sinusoidal distributed load in the static analysis. Laminated composite, isotropic, and transversely isotropic plates are considered. The governing equations are obtained utilizing the virtual work principle. The differential equations are solved via Navier's procedure. The results obtained from the developed theory are compared with other higher-order theories considered in the previous studies and 3D elasticity solutions. The results showed that the proposed theory accurately and effectively predicts the bidirectional bending responses of laminated composite plates. Several parametric studies are presented to illustrate the various parameters influencing the static response of the laminated composite plates.

• 한국전문물리치료학회지
• /
• 제12권2호
• /
• pp.28-36
• /
• 2005

The purpose of this study was to investigate the effects of the increasing ankle range motion program on ambulation and balance for the elderly with balance disorder. Eighteen elderly subjects were administered with a timed test twice; approximately 4 weeks apart. The exercise group participated in a fall prevention exercise class at the Y.S. Senior Welfare Center of the Seoul Metropolitan Government. The session consisted of a stationary cycle, static stretching ankle joints, balance boards, and progressive resistive exercises using the Thera-band. The results were as follows: Firstly, the increasing ankle range of motion program was effective on the exercise group. Gait-speed was improved (p<.005). Secondly, balance was significantly improved (p<.000). Thirdly, increasing ankle range of motion program was effective in ankle dorsiflexion which was the major risk factor for falls among the elderly. Differences in gait and balance between the groups were examined using a paired t-test (p<.05). The exercise group demonstrated significantly higher values of gait-speed, ankle range of motion, and balance when compared with the non-exercise group. The results of this study suggest that the increasing ankle range of motion program is an effective intervention for the elderly with balance disorder.

• Structural Engineering and Mechanics
• /
• 제50권4호
• /
• pp.487-500
• /
• 2014

An analytical solution for the nonlinear in-plane free oscillations of the suspended cable which contains the quadratic and cubic nonlinearities is investigated via the homotopy analysis method (HAM). Different from the existing analytical technique, the HAM is indeed independent of the small parameter assumption in the nonlinear vibration equation. The nonlinear equation is established by using the extended Hamilton's principle, which takes into account the effects of the geometric nonlinearity and quasi-static stretching. A non-zero equilibrium position term is introduced due to the quadratic nonlinearity in order to guarantee the rule of the solution expression. Therefore, the mth-order analytic solutions of the corresponding equation are explicitly obtained via the HAM. Numerical results show that the approximate solutions obtained by using the HAM are in good agreement with the numerical integrations (i.e., Runge-Kutta method). Moreover, the HAM provides a simple way to adjust and control the convergent regions of the series solutions by means of an auxiliary parameter. Finally, the effects of initial conditions on the linear and nonlinear frequency ratio are investigated.

• Smart Structures and Systems
• /
• 제26권2호
• /
• pp.213-226
• /
• 2020

In this manuscript, static and dynamic behaviors of geometrically imperfect carbon nanotubes (CNTs) subject to different types of end conditions are investigated. The Doublet Mechanics (DM) theory, which is length scale dependent theory, is used in the analysis. The Euler-Bernoulli kinematic and nonlinear mid-plane stretching effect are considered through analysis. The governing equation of imperfect CNTs is a sixth order nonlinear integro-partial-differential equation. The buckling problem is discretized via the differential-integral-quadrature method (DIQM) and then it is solved using Newton's method. The equation of linear vibration problem is discretized using DIQM and then solved as a linear eigenvalue problem to get natural frequencies and corresponding mode shapes. The DIQM results are compared with analytical ones available in the literature and excellent agreement is obtained. The numerical results are depicted to illustrate the influence of length scale parameter, imperfection amplitude and shear foundation constant on critical buckling load, post-buckling configuration and linear vibration behavior. The current model is effective in designing of NEMS, nano-sensor and nano-actuator manufactured by CNTs.

• Structural Engineering and Mechanics
• /
• 제88권5호
• /
• pp.501-519
• /
• 2023

This paper introduces a new hybrid structural connection joint that combines shear walls with section steel beams, fundamentally resolving the construction complexity issue of requiring pre-embedded connectors in the connection between shear walls and steel beams. Initially, a quasi-static loading scheme with load-deformation dual control was employed to conduct low-cycle repeated loading experiments on five new connection joints. Data was acquired using displacement and strain gauges to compare the energy dissipation coefficients of each specimen. The destruction process of the new connection joints was meticulously observed and recorded, delineating it into three stages. Hysteresis curves and skeleton curves of the joint specimens were plotted based on experimental results, summarizing the energy dissipation performance of the joints. It's noteworthy that the addition of shear walls led to an approximate 17% increase in the energy dissipation coefficient. The energy dissipation coefficients of dog-bone-shaped connection joints with shear walls and cover plates reached 2.043 and 2.059, respectively, exhibiting the most comprehensive hysteresis curves. Additionally, the impact of laminated steel plates covering composite concrete floors on the stiffness of semi-rigid joint ends under excessive stretching should not be disregarded. A comparison with finite element analysis results yielded an error of merely 2.2%, offering substantial evidence for the wide-ranging application prospects of this innovative joint in seismic performance.

• Advances in materials Research
• /
• 제13권5호
• /
• pp.335-353
• /
• 2024

In the present paper, a simple quasi-3D integral higher-order beam theory (HBT) is presented, in which both shear deformation and thickness stretching effects are included for mechanical analysis of advanced composite beams with simply supported boundary conditions, handling mainly bending, buckling, and free vibration problems. The kinematics is based on a novel displacement field which includes the undetermined integral terms and the parabolic function is used in terms of thickness coordinate to represent the effect of transverse shear deformation. The governing equilibrium equations are drawn from the dynamic version of the principle of virtual work; whereas the solution of the problem is obtained by assuming a Navier technique for simply supported advanced composite beams subjected to sinusoidally and uniformly distributed loads. The correctness of the present computational method is checked by comparing the obtained numerical results with quasi-3D solutions found in the literature and with those provided by other shear deformation beam theories. It can be confirmed that the proposed model, which does not involve any shear correction factor, is not only accurate but also simple and useful in solving the static and dynamic response of advanced composite beams.

• 전기전자학회논문지
• /
• 제13권4호
• /
• pp.116-124
• /
• 2009

근래 휴대 단말기용 모뎀 칩셋이나 멀티미디어 프로세서의 CPU성능은 노트북PC에 버금가는 수준으로 향상되면서 휴대단말기가 전자기기의 컨버전스화를 주도하는 아이콘으로 떠오르고 있다. 더불어 DMB, 디지털 카메라, 화상통화, 인터넷 검색 등이 기본적으로 제공되면서 소형크기의 휴대 단말기용 디스플레이에서도 화질에 대한 관심이 높아지고 있다. 휴대단말기의 경우 야외에서 태양광과 같은 주변광원의 변화로 동일한 영상이 열화 또는 과도하게 밝아져 보이는 야외 시인성 문제를 해결해야 하며, 더구나 최근 터치방식 패널이 휴대단말기 디스플레이 장치에 사용되면서 ITO 필름에 의한 투과율 손실로 디스플레이 화면의 컨트라스트 저하가 더해지고 있다. 본 논문에서는 휴대 단말기용 영상개선 SoC를 위해 영상 개선 알고리즘을 개발하였고 이에 대한 성능 비교를 수행하였다. 컨트라스트 개선을 위해 적응형 기법으로 Clipped Histogram Stretching을, 정적 기법으로 S형 곡선조정과 Gain 조정 기법을 사용하였고 야외 시인성 개선을 위해서는 CIELCh 색공간에서 외부 조도센서의 정보에 따라 명도(Lightness)와 채도(Chroma)가 조절될 수 있도록 하였다. 개발한 알고리즘에 대한 성능평가는 결과영상의 히스토그램, RGB 화소값 분포도, 엔트로피 그리고 동적영역 확장비 등을 통해 분석을 진행하였다.