• Journal of Electrical Engineering and Technology
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• v.1 no.1
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• pp.106-109
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• 2006

In this paper, the design and characteristics of a novel ultrasonic motor are investigated. Such a motor is appropriate far use in the optical zoom or auto focusing functions of the lens system in mobile phones. Its design and simulation of performances are carried out by FEM commercial software (ATILA). The shape of the motor is similar to a square without one side, on which an optical lens can be mounted. Two sheets of piezoelectric ceramics are adhered to both sides of two legs of the elastic body, respectively To drive the ultrasonic motor, the voltage is applied to two sheets of piezoelectric ceramics bonded to one leg. The rotation direction can be easily changed by switching the piezoelectric sheets bonded to the other leg, to which voltage is applied. A proto type of the motor is fabricated and its outer size is $10^*10^*2[mm3]$ including the camera lens of which the diameter is 7.5(mm). Its power consumption is about 0.3[W] and the speed of rotation is adjustable from 10 to 200[rpm] according to the applied voltage

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.4
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• pp.141-150
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• 2019

Purpose : This study examined the hand function and visual motor integration capabilities in 30 children with developmental disabilities. The children were divided into an experimental group (n=20) that received digital sensory perception training and a control group (n=10) that did not receive this training. Methods : Training was conducted a total of 12 times for six weeks, for 50 minutes a day, twice a week, for the experimental group. The Jebsen-Taylor Hand Function Test was used to determine the hand function before and after the intervention, and the Beery VMI-6 was performed to identify the visual motor integration capability. Results :After the intervention, the ability to perform hand functions and visual motor interaction increased significantly in the experimental group but not in the control group. Digital sensory training therefore had a positive effect on the hand function and visual motor integration in children with developmental disabilities. Conclusion : A digital sensory perception training program is an arbitration method that can positively improve the hand function and visual motor integration ability in children with developmental disabilities.

• Physical Therapy Korea
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• v.12 no.1
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• pp.91-99
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• 2005

We assessed whether the use of a symmetrical upper limb motion trainer in daily repetitive training for a 6-week period reduced spasticity and improved motor function in three chronic hemiparetic patients. Upper limb motor impairment and disability were measured by the Fugl-Meyer Assessment (FMA), Modified Ashworth Scale (MAS) and Manual Muscle Test (MMT), respectively. The electromyography (EMG) of the affected hand was recorded during isometric wrist flexion and extension. In all patients, FMA and MMT scores were significantly improved after the 6-week training. However, MAS scores of the affected wrist spasticity did not change considerably. Onset and Offset delays in muscle contraction significantly decreased in the affected wrist. The co-contraction ratio of flexor and extensor muscles significantly increased after the 6-week training. Onset and offset delays of the muscle contraction and co-contraction ratio correlated significantly with the patients' FMA. This study showed that repetitive, symmetric movement training can improve upper limb motor functions and abilities in chronic hemiparetic patients. Also, the EMG assessment of motor response is likely to provide insights into mechanisms and treatment strategies for motor recovery in chronic hemiparetic patients.

• Physical Therapy Rehabilitation Science
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• v.10 no.4
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• pp.493-502
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• 2021

Objective: Older adults with mild cognitive impairment (MCI) are more likely to progress to dementia. Motor-cognitive training is applied as a dual-task to improve the cognitive and physical functions of older adults with MCI. The purpose of the study was to know the recent trends in motor training types and outcome measures used for motor-cognitive training in older adults with MCI. Design: Aliterature review Methods: This literature review was conducted in Pubmed, MEDLINE® and Google Scholar with the following key words: older adults, mild cognitive impairment, motor-cognitive training, cognition, and dual-task. The 7 studies were found with the search tool and all studies were randomized controlled trials. Results: In motor-cognitive training in older adults with MCI, 6 studies applied aerobic exercise. And 3 out of 6 studies also applied strengthening exercises. One study applied dual tasks without aerobic exercise. In the 6 studies, overall cognitive and executive function were used as outcome measures, and physical function was evaluated as gait performance. Memory and physical frailty were also used as measurement tools. As a result of all studies, when motor-cognitive training was applied, cognition and physical performance showed significant results. Conclusions: A recent five-year study applied mainly aerobic exercise and strength training to older adults with MCI and found it to improve cognitive and physical performance.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.4
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• pp.235-245
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• 2024

We developed and validated a portable tablet-based system to assess brain motor control abilities by engaging participants in a manual tracking task with both visible and invisible targets, thereby eliciting feedback and feedforward control mechanisms. We measured the accuracy of these mechanisms using error terms, comparing 1) the performance of the dominant and non-dominant hands and 2) the intervals of feedback and feedforward control. We showed that the dominant hand demonstrated greater accuracy than the non-dominant hand, particularly when tracking a faster-moving visible target. Furthermore, the non-dominant hand transitioned from feedback to feedforward control at a slower target speed compared to the dominant hand. This suggests differential motor control processing between hands. We present this tablet-based system as an accessible and versatile tool for assessing feedback and feedforward control during target tracking tasks, based on feedback-error learning theory. It enables efficient analysis of motor development in children, motor decline in older adults, and stroke rehabilitation outcomes from a brain motor control perspective.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.10
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• pp.1425-1435
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• 2013

The useful method for determining parameters of weighting functions used to design the $H_{\infty}$ current controller for attenuating the current ripple due to saliencies which SPMSM(Surface Permanent Magnet Synchronous Motor) also incorporates is described. To analyze the effect, the current ripple due to the structural and the saturation saliencies, the SPMSM model with nonlinear inductance function depending on the two independent variables, rotor position and stator current is simulated. After analysis, parameters of the weighting functions for $H_{\infty}$ current controller is selected to satisfy the robust stability, robust performance and specific performance in time and frequency domain by using the PSO(Particle Swarm Optimization) algorithm in the linear SPMSM model. Especially, the robust performance is proved that the selected weighting functions play a role in reducing the current ripple caused by the saliencies of SPMSM at the desired frequency range by the simple experiment.

• Physical Therapy Korea
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• v.22 no.2
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• pp.11-20
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• 2015

The purpose of this study was to evaluate the effect of dual-task training with cognitive effort on the walking and balance functions of chronic stroke patients. The study included 14 chronic stroke patients, who were randomly divided into the experimental group (EG) and control group (CG), each with 7 patients. The EG performed the dual-task training with cognitive effort 3 times a week, 30 minutes for 4 weeks, where as the CG performed single-task training three times a week, for 30 minutes for 4 weeks. Outcome assessments were made with 10 m walk test, timed up and go test, 6 minutes walk test, and Berg balance scale. In within-group comparison, subjects from the EG showed significant differences in all variables (p<.05), while subjects from the CG showed only significant differences in 6 minutes walk test, and Berg balance scale (p<.05). Further, there was significant difference in the improvement rate of 10 m walk test. The findings suggest that the dual-task with cognitive effort may be beneficial for improving walking and balance functions of patients with chronic stroke.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.4B no.4
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• pp.184-189
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• 2004

In this paper, multi-object optimization based on a progressive quadratic response surface method (PQRSM) and a time stepping finite element method (FEM) is proposed. The new PQRSM and FEM are able to decide optimal geometric and electric variables of the switched reluctance motor (SRM) with two objective functions: torque ripple minimization and average torque maximization. The result of the optimum design for SRM demonstrates improved performance of the motor and enhanced relationship between torque ripple and average torque.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.3
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• pp.208-213
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• 2012

With great advancement of the automobile functions, environmental factors become important performances, especially noise. This paper investigates noise sources of outer rotor type BLDC motor using in the air-conditioner of the automobiles. To this end, this paper is analyzed two viewpoints, structural and electromagnetic causes. Structural analysis is conducted through modal test and analysis. For modal analysis, 3D finite element analysis is carried out using commercial program ansys. Electromagnetic causes are analyzed from local force that is computed by Maxwell stress tensor method. Local force excites structure of motor directly. Finally, correlation analysis is performed to determine effect between noise causes.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.9
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• pp.675-681
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• 2014

This paper proposes a fault diagnosis system for an induction motor. This system uses empirical mode decomposition(EMD) to extract fault signatures and multi-layer perceptron(MLP) neural network to facilitate an accurate fault diagnosis. EMD can not only decompose a signal adaptively but also provide intrinsic mode functions(IMFs) containing natural oscillatory modes of the signal. However, every IMF does not represent fault signature, an IMF selection algorithm based on harmonics and their energy of each IMF is proposed. The selected IMFs are utilized for fault classification using MLP and this system shows approximately 98 % diagnosis accuracy for the fault vibration signal of the induction motor.