• Investigative Magnetic Resonance Imaging
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• v.13 no.1
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• pp.47-53
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• 2009

Purpose : Although it's been known for half a century that unique structures have evolved in the cerebellum and they then became greatly enlarged in the human brain, the function of these structures still remains unknown. The purpose of this study was to assess cerebellar activation during motor, sensory, word generation, listening comprehension, and working memory tasks with using functional magnetic resonance imaging (fMRI). Materials and Methods : Eleven healthy right-handed subjects (Male: female, 6:5, mean age: 27.4years) were imaged on a Siemens 1.5T scanner. Whole brain functional maps were acquired using BOLD EPI sequences in the axial plane. Each paradigm consisted of five epochs of activation vs. the control condition. The activation tasks consisted of left finger complex movement, sensory stimulation of the left hand, word generation, listening comprehension, and working memory tasks. The reference function was a boxcar waveform. The activation maps were thresholded at p = 0.001. SPM 5 evaluated the activated areas and responses within the cerebellum. Results : Cerebellar activation was observed on motor task, word generation task, and working memory task. There were 949 activated areas and the mean fitted and adjusted response was 0.68 during the motor task. There were 319 activated areas and the mean fitted and adjusted response was 0.15 during the word generation task. There were 330 activated areas and the mean fitted and adjusted response was 0.26 during the working memory task. Conclusion : Our results suggest that the cerebellum is involved in a variety of functional tasks, including motor, word generation, and working memory tasks. However, during the motor task, the cerebellum showed a large activated area and a high response. Cerebellar function can be evaluated by fMRI.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1339-1343
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• 2004

This paper presents a development of the control algorithm and Pick & Placer. The Pick & Placer provides a powerful multi-task system that includes both graphical and remote interface. Users can easily set up sorting parameters and record important data including wafer number, data, and operator information. This System sets up a dustproof device and massively machined components to provide an extremely stable sorting environment. Precise resolution and accuracy result from using machine vision, a pneumatic slide drive and close -looped positioning.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.12a
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• pp.251-254
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• 2001

본 논문에서는 Self Organizing Map을 이용하여 fMRI data를 분석해 보았다. fMRl (functional Magnetic Resonance Imaging)는 인간의 뇌에 대한 비 침투적 연구 방법 중 최근에 각광받고 있는 것이다. Motor task를 수행하고 있는 피험자로부터 image data를 얻어내어 SOM을 적용하여 clustering한 결과 motor cortex 영역이 뚜렷하게 clustering 되었음을 알 수 있었다.

• The Journal of Korean Physical Therapy
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• v.14 no.3
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• pp.418-432
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• 2002

본 연구의 목적은 다음과 같이 네 가지이다. 첫째, dual-strategy hypothesis 모델의 이론적인 배경을 서술한다. 둘째, 보행시작 시 (Gait Initiation)와 장애물 보행시작 (Stepping over obstacles)시의 motor task를 dual-strategy hypothesis 모델의 관정에서 서술한다. 셋째, 파킨슨씨 환자군과 뇌졸증 환자군을 이 모델의 관점에서 서술한다. 마지막으로, dual strategy hypothesis모델의 임상적용 가능성에 대해서 간단히 서술하는 것이다.

• Investigative Magnetic Resonance Imaging
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• v.4 no.1
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• pp.14-19
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• 2000

Purpose : This study was to present the functional brain mapping of both functional magnetic resonance imaging(MRI) and transcranial magnetic stimulation(TMS) in a case of schizencephaly. Materials and methods : A 28-year-old man, who had left hemiplegia and schizencephaly in right cerebral hemisphere, was exacted with both functional MRI and TMS. Motor function of left hand was decreased whereas right hand was within normal limit. For functional MRI, gradient-echo echo planar imaging($TR/TE/{\alpha}$=1.2 sec/90 msec/90) was employed. The paradigm of motor task consisted of repetitive self-paseo hand flexion-extension exercises with 1-2 Hz periods. An image set of 10 slices was repetitively acquired with 15 seconds alternating periods of task performance and rest and total 6 cycles (three ON periods and three OFF periods) were performed. In brain mapping, TMS was performed with the round magnetic stimulator (mean diameter; 90mm). The magnetic stimulation was done with 80% of maximal output. The latency and amplitude of motor evoked potential(MEP)s were obtained from both abductor pollicis brevis(APB) muscles. Results : Functional MRI revealed activation of the left primary motor cortex with flexion-extension exercises of healthy right hand. On the other hand, the left primary motor cortex, left supplementary motor cortex, and left promoter areas were activated with flexion-extension exercises of left hand. In TMS, magnetic evoked potentials were induced in no areas of right cerebral hemisphere, but in 5 areas of left corebral hemisphere from both abductor pollicis brevis. Latency, amplitude, and contour of response of the magnetic evoked potentials in both hands were similar. Conclusion : Functional MRI and TMS in a patient with schizencephaly were successfully used to localize cortical motor function. Ipsilateral motor pathway is thought to be secondary to reinforcement of the corticospinal tract of the ipsilateral motor cortex.

• Journal of Korean Physical Therapy Science
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• v.28 no.1
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• pp.33-45
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• 2021

Background: Children with cerebral palsy have difficulty acquiring motor skills through motor learning due to lack of motor planning of the central nervous system and musculoskeletal dysfunction. Motor learning is the acquisition or modification of movements with the aim of developing skilled movements and behaviors. Cerebral palsy improve motor function through motor learning, and effective motor learning mainly depends on practice parameters such as learning feedback. Therefore, we investigate the effect of motor learning in children with cerebral palsy and try to present the possibility of clinical application. Design: A systemic review. Methods: Research papers were published from Jan, 2010 to Dec, 2020 and were searched using PubMed and Medline. The search terms are 'task specific training' OR 'motor learning' OR 'feedback(Mesh term)' OR 'goal activity' AND 'cerebral palsy(Mesh term)'. A total of eight papers were analyzed in this study. The paper presented the quality level based on the research evidence, and also presented PEDro (Physiotherapy Evidence Database) scores to evaluate the quality of design studies in randomized clinical trials. Results: The results showed that motor learning coaching in children with cerebral palsy improved motor function in post and follow up tests. Also, self-control feedback of motor learning is more effective than external control feedback. 100% external control feedback of motor learning is effective in the acquisition phase and 50% external feedback of motor learning is effective in the retain phase. Conclusion: These results suggest that it will be an important data for establishing evidence on the effect of motor learning arbitration methods in children with cerebral palsy to develop clinical applicability and protocols.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.2
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• pp.148-154
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• 2014

This paper describes problems of the sensorless starting of horizontal axis washing machines with direct drive and suggests solution, which was experimentally verified. Horizontal axis washing machines have very difficult conditions for the drive starting, especially at full load. Inertia of the tub and water, torque from the laundry make load torque at starting higher than rated one and sometimes even higher than the maximum torque of the motor, which makes sensorless starting extremely challenging task. This paper suggests modified open-loop starting, where control system is closed shortly after beginning at low speed and rotates the drum until laundry restructuring. To ensure proper work of the sensorless algorithm at low speed additional measures for increasing of the estimation algorithm performance have been taken. These measures include special algorithm for the drive parameters estimation, which has been developed and verified by the experimental results.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.365-368
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• 2001

The advantage of the squirrel cage induction motor is the brush less rotor. This advantage for operation and maintenance turns out to be a disadvantage for the detection of the cage rotor bar and endring defects, which means that the detection of cage faults is due to the measurement and analysis of only the stator input signals. The monitoring task in an inverter drive is complicated mainly because the voltage and current waveforms are nonsinusoidal and the high dv/dt values from fast switching inverterd distort the measurements. In this paper, we are going to discuss the detection method of broken rotor bar of the inverter fed squirrel cage induction motor by the motor current signature analysis(MCSA) and the opening terminal voltage signal analysis.

• Journal of Electrical Engineering and Technology
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• v.3 no.1
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• pp.68-78
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• 2008

This paper introduces a complete package for SRM drive on Power System Computer-Aided Design/Electromagnetic Transients (PSCAD/EMTDC). A three-phase SRM drive is modeled and simulated on PSCAD. The motor is modeled using an accurate nonlinear analytical model that takes into consideration the machine nonlinearities. A current control algorithm is applied for torque ripple minimization to achieve a smooth output torque which is necessary for high performance applications. The motor drive is tested for four-quadrant operations. The modeled SRM is capable of operating as a motor or generator during clockwise and counterclockwise motions. The proposed package helps in understanding the operational principles of switched reluctance motors, investigating the dynamic characteristics of SRM drives, and achieving a high performance dynamic control task.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.4 s.235
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• pp.518-525
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• 2005

The electromagnetic noise generates when natural frequencies of a stator core with wingdings and frame coincide with or approach natural frequencies of the magnetic motive force. In order to suppress such noise, the estimation of natural frequencies of the motor is important at the design stage. However, the natural frequency analysis is not so easy because motor stator is in the laminated plate structure and windings are composed of wires, insulation sheets and vanishs. Thus the accurate prediction of the equivalent material properties of windings becomes an essential task. In this paper, we derive the equivalent material properties using homogenization methods.