• Structural Engineering and Mechanics
• /
• 제75권4호
• /
• pp.435-444
• /
• 2020

Ultrasonic guided wave testing is a very promising non-destructive testing method for rails, which is of great significance for ensuring the safe operation of railways. On the basis of the semi-analytical finite element (SAFE) method, a analytical model of 59R2 grooved rail was proposed, which is commonly used in the ballastless track of modern tram. The dispersion curves of ultrasonic guided waves in free rail and supported rail were obtained. Sensitivity analysis was then undertaken to evaluate the effect of rail elastic modulus on the phase velocity and group velocity dispersion curves of ultrasonic guided waves. The optimal guided wave mode, optimal excitation point and excitation direction suitable for detecting rail integrity were identified by analyzing the frequency, number of modes, and mode shapes. A sinusoidal signal modulated by a Hanning window with a center frequency of 25 kHz was used as the excitation source, and the propagation characteristics of high-frequency ultrasonic guided waves in the rail were obtained. The results show that the rail pad has a relatively little influence on the dispersion curves of ultrasonic guided waves in the high frequency band, and has a relatively large influence on the dispersion curves of ultrasonic guided waves in the low frequency band below 4 kHz. The rail elastic modulus has significant influence on the phase velocity in the high frequency band, while the group velocity is greatly affected by the rail elastic modulus in the low frequency band.

• 대한기계학회논문집A
• /
• 제35권8호
• /
• pp.957-964
• /
• 2011

본 연구에서는 압전 밴드 갭 구조물(포논 결정) 에 대한 체적 탄성파의 전파 특성을 주파수 및 모드 별로 파악하기 위한 유한 요소법의 적용 방안을 제안하였다. 이를 위해 체적 탄성 진행파의 면내 모드 뿐만 아니라 면외 모드를 포함하도록 3 차원 주기 경계 조건을 고려하였다. 특히, 체적 탄성파 모드 간의 비연성 특성을 전기 분극 방향에 따라 유도한 다음, 그 결과를 유한 요소 모델링에 반영하였다. 제안된 방법은 실제 시뮬레이션을 통해 다양한 형태의 압전 밴드 갭 구조물의 파동 특성 분석에 적용될 수 있는 일반적이고 효율적인 방법임을 확인하였다.

• 대한정형도수물리치료학회지
• /
• 제29권1호
• /
• pp.69-79
• /
• 2023

Purpose: This study examined the possibility of muscle strength and balance ability improvement through coordinative locomotor training by making a difference on the supporting plane using a resistance band for adolescent athlete of Taekwondo sparring athletes. Methods: A total of 22 students were selected as to the participants of the study, and 11 students each were randomly assigned to the control and experimental group for coordination locomotor training using a resistance band on stable and unstable supporting surface. The training period was 60 min, three times a week, for 8 weeks in total. To confirm changes on balance ability of each participant, balance assessment devices are used. Moreover, surface electromyography was used for muscle strength evaluation. Results: After coordinated locomotor training using a resistance band for 8 weeks, the difference bet ween groups was not significant; Also, the improvement in strength was no significant difference in other muscles in the between groups, but there was a significant in the muscle activity of the rectus muscle of the right thigh in the experimental group. Conclusion: The participants demonstrated that coordinative locomotor training using the elastic band on an unstable supporting surface was able to obtain junctional effects for the prevention of exercise injuries in youth taekwondo sparring athletes, and muscle activity exercise of the rectus muscle of the right thigh was particularly effective.

• 로봇학회논문지
• /
• 제13권3호
• /
• pp.157-163
• /
• 2018

This paper deals with the development and application of control algorithms for series elastic relief robots for rescue operations in harsh environment like disasters or battlefield. The joint controller applied in this paper has a cascade structure combining inner loop for torque control and outer loop for position control. The torque loop contains feedforward and feedback controller and disturbance observer for independent, decentralized joint control. The effect of the elastic component and motor dynamics are treated as the nonlinear disturbance and compensated with the disturbance observer of torque controller. For the collision detection, Band Designed Disturbance Observer is configured to recognize/respond to external disturbance robustly in the continuously changing environment. The controller is applied to a 7-dof series elastic manipulator to evaluate the torque tracking and collision detection/response performance.

• 대한물리의학회지
• /
• 제12권1호
• /
• pp.83-91
• /
• 2017

PURPOSE: The purpose of this study was to investigate the effects of stretching and elastic band exercise on the knee space distance and plantar pressure distribution in people with genu varum. METHODS: The subjects of this study were students of a college who had genu varum of 14 subjects. The subjects were randomly divided into two groups as a stretching group (n=7, 4 males and 3 females, age: $20.14{\pm}2.54years$, height: $167.1{\pm}9.78cm$, weight: $58.6{\pm}10.13kg$) and a Thera-band group (n=7, 5 males and 2 females, age: $19.85{\pm}2.04years$, height: $166.5{\pm}5.82cm$, weight: $54.2{\pm}5.59kg$). The stretching and the There-band exercises were performed three times per a week, for four weeks. We measured changes in plantar pressure during walking, using a Gait Analyzer and distance of both knees at pre and post-intervention. RESULTS: These results suggest that the space distance of both knees showed differences before and after the intervention. The plantar pressure distribution was no changes in both groups before and after the intervention except for the left foot in a stretching group. CONCLUSION: As a result, the space distance of knees in both groups was significantly reduced. These result suggested that the Thera-band and stretching exercises were effective ways in alleviating genu varum.

• 한국의류산업학회지
• /
• 제8권6호
• /
• pp.618-626
• /
• 2006

This research explored the actual conditions, problems and design preferences of dementia inpatient clothing. Data were collected by surveying 21 dementia hospitals and nursing care facilities and 87 caregivers and nurses of dementia hospitals. The collected data were analysed through frequency analysis, descriptive analysis and factor analysis. The results were as follows, First, the inpatient clothes of dementia hospitals were two-piece styles, the shirts of front opening with buttons and pants of no opening with elastic band. Those of dementia care facilities were two piece styles of shirts and pants, training suits or private plain clothes not uniform. Severe dementia inpatient dressed uniforms of the jump suits or two piece styles in some dementia care facilities. Second, the problems of dementia inpatient clothing were composed of suitability of raw and subsidiary clothing material, diversity of design and size, durability and form stability of clothes and elastic bands. Third, the design elements similar to those of existing inpatient clothing were preferred with regard to improving dementia inpatient clothing. That is, the design preferences of shirts showed front opening style with buttons, round neckline and a three-quarter-length sleeves. Those of pants came out no opening style with elastic band and full length. Also, pink color and natural patterns were preferred, and the private plain clothing of inpatient and fusion Han-bok style were somewhat preferred.

• 대한통합의학회지
• /
• 제8권2호
• /
• pp.109-119
• /
• 2020

Purpose : The purpose of this study was to investigate the effects of a combined exercise program using a ballet bar and elastic bands on the body composition, physical strength, and postural correction of middle-aged women. Methods : The subjects were 28 middle-aged women with no ballet experience. They were divided into an experimental group (n=14; exercise group) and a control group (n=14; non-exercise group) through random sampling. The experimental group underwent an exercise program using a ballet bar and elastic bands for 50 minutes twice a week for 12 weeks, whereas the control group performed no exercise. The subjects in both group had their body composition, physical fitness, and postural angles measured before and after the intervention. A paired t-test was used to compare pre- and post-test values within each group, and a two-way repeated measures ANOVA was employed to compare pre- and post-test changes between the two groups. Results : Regarding body composition, statistically significant differences in BMI (p<.05), body fat percentage (p<.001), and muscle mass (p<.001) were observed between the two groups before and after the intervention. For physical fitness, the experimental group showed statistically significant increases in quick reflexes (p<.001), muscle endurance (p<.001), and muscle strength (p<.001). For postural correction, the experimental group exhibited statistically significant decreases in all variables: the head (p<.001), shoulder (p<.001), cervical tilt (p<.001), right-left pelvic tilt (p<.001), and anterior-posterior pelvic tilt (p<.001). Conclusion : A combined exercise program using a ballet bar and elastic bands had positive effects on the body composition, physical fitness, and postural correction of middle-aged women.

• 대한정형도수물리치료학회지
• /
• 제29권3호
• /
• pp.63-72
• /
• 2023

Background: This study investigated the effects of face-to-face and non-face-to-face McKenzie exercises and elastic band strengthening exercises on falls and fitness in older adults. Methods: A total of 44 subjects were divided into a face-to-face group (FG; n=22) and a non-face-to-face group (NFG; n=22) who met older adults. Both groups used McKenzie exercises and strength training with elastic bands The fall efficacy scale (K-FES) and glycosylated hemoglobin (HbA1c) Pro were used to compare the senior fitness test (SFT). Results: No significant differences were detected between the two groups before the intervention; however, a significant difference was noted in the K-FES scores after the intervention. The change in HbA1c after the intervention was not statistically significant in the FG or the NFG, and no significant difference was detected between the two groups. The change in lower limb muscle strength in the elderly physical fitness test showed no significant difference between the two groups before or after the intervention. The change in upper limb flexibility after the intervention was not significantly different in the FG or NFG, indicating no significant difference between the two groups. The change in the 3-meter round-trip test after the intervention was significantly different in both the FG and NFG groups, but the difference between the groups was not statistically significant. The change in the grip strength test of the dominant hand showed no significant difference after the intervention in the FG or the NFG, and the difference between the FG and NFG groups was not statistically significant. The dominant foot external standing after the intervention was significantly improved in the FG, but no significant difference was detected in the NFG, and the difference between the two groups was not statistically significant. Conclusion: The study findings revealed that FG and NFG McKenzie exercises and elastic band strengthen exercises were equally effective at preventing falls and improving fitness in older adults.

• The Journal of Korean Physical Therapy
• /
• 제21권1호
• /
• pp.27-34
• /
• 2009

Purpose: The purpose of this study was to evaluate the effects of 8weeks of exercise station training with elastic band and swissball on body compositions and balance ability for elderly women. Methods: This study was designed as a experimental pre-post exercise station training evaluation. The experimental group performed exercises with band and ball for 8 weeks. The effects of the program were assessed using instruments measuring the body compositions and balance ability before and after participating in the training program. Results: There were no significant differences in body compositions and index of falling down risk, however, there were significant differences with balance index, functional reach test and one leg stand test. Conclusion: These findings suggest that exercise station training with elastic band and swissball can serve as an effective means of improving balance ability in elderly women.

• 국제물리치료학회지
• /
• 제11권4호
• /
• pp.2244-2252
• /
• 2020

Background: Thera-Band, Narrow squats, Kinesiology taping helps in the reduction of loading on the knee joints. Despite the fact that the varus knee negatively affects the alignment of the lower extremities, most of the studies have analyzed each independently. Objectives: To investigate the effects of a complex exercise program consisting of elastic band exercises and squat exercises on the distance between the inner knees and balance in young adults with genu varum. Design: A cluster randomized controlled trial. Methods: The complex exercise group performed resistance exercises using an elastic band. The taping group used kinesiology tape on the vastus lateralis and biceps femoris. To select those to be included in the study, we measured the distance between the knees using digital Vernier calipers and to measure the balance ability, we used a balance training system. The data were analyzed with the independent t-test and paired t-test. Results: The study indicated a significant difference in the distance between the knees between the two groups, but no significant differences in the dynamic balance between the groups. Also, the static balance comparison between the groups according to the intervention method included the trace length, C90 area, C90 angle and velocity. There were no significant differences in the static balance between the groups. In addition, the complex exercise program was more effective than taping. Conclusion: The results of this study demonstrate that the complex exercise program and taping decrease the between both the knee and increase the balance.