• Steel and Composite Structures
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• v.49 no.3
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• pp.325-335
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• 2023

The missile is affected by both spinning and axial motion during its movement, which will have a very adverse impact on the stability and reliability of the missile. This paper regards missiles as cylindrical shell structures with spinning and axial motion. In this article, the forced vibration of carbon nanotube-reinforced composites (CNTRCs) cylindrical shells with spinning motion and axial motion is investigated, in which the clamped-clamped and simply-simply supported boundary conditions are considered. The displacement field is described by the first-order shear theory, and the vibration equation is deduced by using the Euler-Lagrange equation, after dimensionless processing, the dimensionless equation of motion is obtained. The correctness of this paper is verified by comparing with the results of the existing literature, in which the simply-simply supported ends are taken into account. In the end, the effects of different parameters such as spinning velocity, axial velocity, carbon nanotube volume fraction, length thickness ratio and load position on the resonance behavior of cylindrical shells are given. It can be found that these parameters can significantly change the resonance of axially moving and rotating moving CNTRCs cylindrical shells.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1512-1515
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• 1997

One of the advantages of master-slave teleoperation is scaling concept such as position scaling, force scaling Meanuhile, lots of quantization effects are generated from position and force sensors in the master and slave manipulator. In this paper, to show the output error caused by the quantizaion effects from the position sensor and position scaling factor, simulation is done for free motion without contact in slave side. Transfer functiion model in which the quantization effect is assumed to be a disturbance input to the system is derived. Model shows that Jacobian, scaling factors, and controller affect the output by quantization effects form esnsors. One dof master and slave are used for simulation. In our study, the higher sensor resolution decreases the output error form quantization. Scaling factors can amplify the quantizatiion effects form the sensors in master and slave manipulators.

• Proceedings of the Optical Society of Korea Conference
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• 1995.06a
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• pp.138-148
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• 1995

A reduced description of the dynamics of carriers in excited semiconductors is presented. Fristly, a time-convolutionless equation of motion for the reduced density operator is derved from the microscopic Liouville wquation operator method. Secondly, the quantum kinetic equations for intercting electron-hole parirs near band-edge in semiconductors under an extermal optical field are obtained from the equation of motion for the reduced density operator. The non-Markovian optical gain of a driven semiconductor is derived including the many-body effects. plasma screening and excitinic effects are taken into account using as effective Hamiltonian in the time-dependent Hartree-Fock approximation. it is shown that the line shape of optical-gain spectra gain is enhanced by the exicitonic effects caused by the attrative electron-hole Coulomb interaction and the interference effects (renormalized memory effects) between the extermal driving filed and the intermal driving Filed and the stochastic reservoir of the system.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.22 no.2
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• pp.1-7
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• 2016

Background: The purpose of this study was to investigate the effects of between modified mulligan technique and modified mulligan technique with taping on the active range of motion & passive range of motion, scapula index into the stroke patients. Methods: The subjects with stroke were randomly divided into two groups. Group 1 (n=9) was conducted modified mulligan technique and Group 2 (n=9) was conducted modified mulligan technique with taping week three times for 4weeks. Active range of motion (AROM), passive range of motion (PROM) and scapula index (SI) were measured by goniometer and tape measure. Wilcoxon signed-rank tests were used to compare differences before and after intervention. Mann-Whitney U-test were conducted to compare before to after intervention in the two groups. Results: AROM was significantly different both groups (p<.05) and between groups were not significantly different into pre and post intervention (p>.05). PROM was significantly different both groups (p<.05) however, between groups were not significantly different into pre and post intervention (p>.05). SI was significantly different only group 2 and between groups were not significantly different (p>.05). Conclusions: This study demonstrated effective bo-th modified mulligan technique and modified mulligan technique with taping on the active range of motion and passive range of motion. Because only modified mulligan technique with taping are effective on the scapula index we recommend modified mulligan technique with taping than modified mulligan technique.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.2
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• pp.43-51
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• 2018

PURPOSE: Stroke patients have limited ankle range of motion and balance problems. The purpose of this study was to determine the effects of Kaltenborn orthopedic manual therapy, Evjenth-hamberg stretching, and combination of both on ankle dorsiflexion range of motion and dynamic balance ability in stroke patients. METHODS: Thirty patients were placed in three groups, each of which received different treatments: Kaltenborn orthopedic manual therapy (15 mins), Evjenth-hamberg stretching (15 mins), or Kaltenborn orthopedic manual therapy with Evjenth-hamberg stretching (30 mins). Each group received three exercise sessions per week during four weeks. To determine its effectiveness of interventions an evaluation was carried out. ankle dorsiflexion range of motion was gauged using a tiltmeter application, and dynamic balance ability was measured using the Berg balance scale. RESULTS: All groups revealed significant improvements in ankle dorsiflexion range of motion, Berg Balance Scale (BBS) score before and after the intervention, and Kaltenborn orthopedic manual therapy with Evjenth-hamberg stretching group showed a significant improvement in ankle dorsiflexion range of motion and BBS score in comparison to other groups. CONCLUSION: We found out that each individual method was effective in ankle dorsiflexion range of motion, dynamic balance ability in stroke patients, and the combined method was more effective.

• Journal of the Korean Society of Physical Medicine
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• v.2 no.2
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• pp.113-124
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• 2007

Purpose : The purpose of this study was to investigate the effects of joint mobilization on the rang of motion and pain of patient with chronic low back pain. Methods : The subjects were consisted of thirty patients with chronic low back pain(19 females, 11 males ; mean aged 59.93) from 50 to 71. All subjects randomly assigned to the modalities treatment group, joint mobilization group. Modalities treatment group received hot pack used thermal therapy for 20minutes and ICT used electrical therapy for 15minutes, joint mobilization group received modalities treatment with sustained natural apophyseal glides(SNAGS) techniques of Mulligan for 10minutes per day and three times a week during 2 weeks period. Visual Analogue Scale(VAS) was used to measure subjective pain level. Remodified Schober test(RST) was used to measure range of motion of lumbar spine. All measurements of each patients were measured at pre-treatment and 2 weeks post-treatment. Results : The results of this study were summarized as follows : 1. VAS was joint mobilization group showed significantly decreased more than modalities treatment group (p<.05). 2. The lumbar flexion range of motion was joint mobilization group showed significantly decreased more than modalities treatment group(p<.05). 3. The lumbar extension range of motion was joint mobilization group showed significantly decreased more than modalities treatment group(p<.05). 4. The lumbar left lateral flexion range of motion was joint mobilization group showed significantly decreased more than modalities treatment group(p<.05). 5. The lumbar right lateral flexion range of motion was joint mobilization group showed significantly decreased more than modalities treatment group(p<.05). Conclusion : These data suggests that SNAGS of Mulligan is beneficial treatment for chronic low back pain.

• Korean Journal of Applied Biomechanics
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• v.19 no.1
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• pp.27-36
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• 2009

The purpose of this study was to identify effects of restricted trunk motion on the performances of the maximum vertical jump. Ten healthy males performed normal countermovement jump(NJ) and control type of countermovement jump(CJ), in which subjects were required to restrict trunk motion as much as possible. The results showed 10% decreases of jumping height in CJ compared with NJ, which is primarily due to vertical velocity at take off. NJ with trunk motion produced significantly higher GRF than RJ, especially at the early part of propulsive phase, which resulted from increased moments on hip joint. And these were considered the main factors of performance enhancement in NJ. There were no significant differences in the mechanical outputs on knee and ankle joint between NJ and RJ. With trunk motion restricted, knee joint alternatively played a main role for propulsion, which is contrary on the normal jump that hip joint was highest contributor. And restricted trunk motion resulted in the changes of coordination pattern, knee-hip extension timing compared with normal proximal-distal sequence. In conclusion these results suggest that trunk motion is effective strategy for increasing performance of vertical jumping.

• Physical Therapy Rehabilitation Science
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• v.10 no.1
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• pp.10-15
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• 2021

Objective: Limited ankle dorsiflexion is related to ankle injuries. There are various exercises to increase the flexibility of the gastrocnemius for improving the passive range of motion in ankle dorsiflexion. However, to performances in daily activities and athletic sports and higher efficiency of walking and running, both ankle dorsiflexion passive and active range of motion are needed. To investigate the effects of combined gastrocnemius stretching and tibialis anterior resistance exercise on ankle kinematics (passive and active range of motion of ankle dorsiflexion) and tibialis anterior muscle activity in subjects with limited ankle dorsiflexion. Design: Cross-sectional single-group repeated measures design. Methods: Fourteen subjects with limited ankle dorsiflexion were recruited (in the right ankle in 7 and the left ankle in 7). All subjects performed gastrocnemius stretching alone and tibialis anterior resistance exercise after gastrocnemius stretching. The passive and active range of motion of ankle dorsiflexion were measured after interventions immediately. The tibialis anterior activity was measured during active range of motion of ankle dorsiflexion measurement. Results: There was no significant difference of ankle dorsiflexion passive range of motion between gastrocnemius stretching alone and the tibialis anterior resistance exercise after gastrocnemius stretching. The tibialis anterior resistance exercise after gastrocnemius stretching significantly increased active range of motion of ankle dorsiflexion compared to gastrocnemius stretching alone (p<0.05). The tibialis anterior resistance exercise after gastrocnemius stretching significantly increased tibialis anterior activity better than did gastrocnemius stretching alone. Conclusions: Thus, subjects with limited ankle dorsiflexion should be encouraged to perform tibialis anterior resistance exercises.

• PNF and Movement
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• v.22 no.2
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• pp.191-199
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• 2024

Purpose: This study aimed to investigate the effects of ankle stretching with intrinsic muscles on ankle range of motion, static and dynamic balance, and gait speed in chronic stroke patients. Methods: The participants were 20 chronic stroke patients, divided into two groups, 10 in the ankle stretching with intrinsic muscles group and 10 in the slant board exercise group. Both groups performed their respective interventions once daily, with three sets per session, five times a week for four weeks. Ankle range of motion, dynamic and static balance, and gait speed were measured before and after the intervention. An independent t-test was used to compare the results between the two groups before and after the intervention. Results: Both groups showed significant improvements in ankle range of motion, dynamic and static balance, and gait speed after the intervention (p < .05). The ankle stretching with intrinsic muscles group showed more significant improvements in ankle range of motion, dynamic and static balance, and gait speed after the intervention compared to the slant board group (p < .05). These results suggest that ankle stretching with intrinsic muscles may be more effective than the slant board for certain outcomes. Conclusion: Ankle stretching with intrinsic muscles is effective in improving ankle range of motion, dynamic and static balance, and walking speed.

• Journal of the Korean Society of Physical Medicine
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• v.19 no.3
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• pp.73-80
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• 2024

PURPOSE: This study examined the immediate effects of thoracic mobility exercises on the thoracic range of motion and chest expansion to provide data on thoracic mobility exercises in adults. METHODS: Adults were assigned randomly to two groups: the group that performed thoracic mobility exercises (TME group; n=10) or the group that performed thoracic mobility exercises using balance tools (TMEB group; n=10). The exercises were performed for 10 min in three different positions. The range of motion and chest expansion were measured before and after the exercise. RESULTS: The within-group comparisons before and after the intervention showed significant differences in the range of motion measurements for lateral flexion and rotation in the TME and TMEB groups (p < .05); difference in measurements of chest expansion was observed only in the TMEB group (p < .05). No significant differences in the range of motion for flexion and extension were observed in either group or during chest expansion in the TME group (p > .05). The between-group comparisons showed a significant difference in left lateral flexion (p < .05), whereas no other measures differed significantly (p > .05). CONCLUSION: The TME and TMEB groups showed significant increases in the thoracic range of motion; the TMEB group showed a significant increase in chest expansion.