• Journal of Power Electronics
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• v.15 no.5
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• pp.1409-1420
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• 2015

In this paper, an algorithm using two bi-quad filters to suppress the wide-band resonance for PMSM servo systems is proposed. This algorithm is based on the double bi-quad filters structure, so it is named, "double bi-quad filter." The conventional single bi-quad filter method cannot suppress unexpected mechanical terms, which may lead to oscillations on the load side. A double bi-quad filter structure, which can cancel the effects of compliant coupling and suppress wide-band resonance, is realized by inserting a virtual filter after the motor speed output. In practical implementation, the proposed control structure is composed of two bi-quad filters on both the forward and feedback paths of the speed control loop. Both of them collectively complete the wide-band resonance suppression, and the filter on the feedback path can solve the oscillation on the load side. Meanwhile, with this approach, in certain cases, the servo system can be more robust than with the single bi-quad filter method. A step by step design procedure is provided for the proposed algorithm. Finally, its advantages are verified by theoretical analysis and experimental results.

• Korean Journal of Health Education and Promotion
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• v.23 no.3
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• pp.65-83
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• 2006

Objectives: This is one of the first efforts to describe incidence of alcohol-related problems and to identify environmental correlates associated with them among colleges. Methods: Date were collected by a sample of 105 college administrators who are in charge of student affairs in colleges nationwide through self-administrated questionnaire. Both logistic and linear multiple regression analyses were employed to identify the correlates associated with alcohol-related problems. Results: Most of colleges(76.6%) under study reported to have at least one alcohol-related problem in previous years. Interpersonal violence was alcohol-related problem taken placed most frequently, followed by making noise episode, having property damaged and motor vehicle accidents. Logistic regression analysis identified factors associated with incidents of alcohol related problems. They included being private colleges, numbers of prevention activities, product promotion and marketing by alcohol industry and alcohol accessibility to drinking context. Multiple regression analyses showed that correlates associated with numbers of alcohol-related problems included being a private college, being located in rural area, having drinking density, product promotion and availability of alternative activities to drinking. Conclusions: Environmental correlates were associated with incidence of alcohol related problems in colleges nationwide. Policy implications were discussed.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.4 no.1
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• pp.26-31
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• 2008

Cerebrovascular Accident(stroke) is that a sudden, nonconvulsive loss of neurologic function due to an ischemic or hemorrhagic intracranial vascular event. If stroke happens at the portion of trigeminal motor nucleus or its control part of cerebral cortex, masticatory muscles will be atrophy or paralyzed. So it is possible that dental occlusion changes after stroke. A 74-aged woman recurred mild stroke 2 month ago, who had experienced severe stroke 2 years ago. After recurrence, suddenly her upper full denture was dropped when lower denture contacted upper one. According to the her occlusion exam, her lower jaw moved back slightly compared with the occlusion of old denture. And her face had asymmetry and lower jaw dislocated to paralyzed side. A 50-aged man was treated because many cervical caries, which would occur because of an aftereffect of stroke, long-herm hospitalization and limits of self oral-care. 6 years ago he had cerebral hemorrhage and he claimed that he cannot bite exactly. Just two pairs of teeth was contact on biting, his lower jaw was located back, too. This two case suggests that dental occlusion can change after stroke.

• Tribology and Lubricants
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• v.26 no.1
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• pp.52-55
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• 2010

This study investigates the friction of the roll stands in the high performance multi- holes slate fin machine which pin is using in heat transfer of radiator, oil cooler, inter cooler, condenser and evaporator. The roll stand part is very important to maintain the high performance fin machine. This multi-holes form roll type is the first time in our country so it will be helpful to increases the export and product of heat transfer. It was include the technical of form rolling system which was self development. Then it will be improve the electric home appliances, future motor vehicle device and industrial machine.

• Transactions on Electrical and Electronic Materials
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• v.17 no.5
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• pp.302-305
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• 2016

In this paper, a low on-resistance and high current driving capability trench gate power metal-oxide-semiconductor field-effect transistor (MOSFET) incorporating a current sensing feature is proposed and evaluated. In order to realize higher cell density, higher current driving capability, cost-effective production, and higher reliability, self-aligned trench etching and hydrogen annealing techniques are developed. While maintaining low threshold voltage and simultaneously improving gate oxide integrity, the double-layer gate oxide technology was adapted. The trench gate power MOSFET was designed with a 0.6 μm trench width and 3.0 μm cell pitch. The evaluated on-resistance and breakdown voltage of the device were less than 24 mΩ and 105 V, respectively. The measured sensing ratio was approximately 70:1. Sensing ratio variations depending on the gate applied voltage of 4 V ~ 10 V were less than 5.6%.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.4
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• pp.551-564
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• 2016

High-speed flight vehicles (HSFVs) such as space launch vehicles and missiles undergo severe dynamic loads which are generated during the launch and in in-flight environments. A typical vehicle is composed of thin plate skin structures with high-performance electronic units sensitive to such vibratory loads. Such lightweight structures are then exposed to external dynamic loads which consist of random vibration, shock, and acoustic loads created under the operating environment. Three types of dynamic loads (acoustic loads, rocket motor self-induced excitation loads and aerodynamic fluctuating pressure loads) are considered as major components in this study. The estimation results are compared to the design specification (MIL-STD-810) to check the appropriateness. The objective of this paper is to study an estimation methodology which helps to establish design specification for the dynamic loads acting on both vehicle and electronic units at arbitrary locations inside the vehicle.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.4
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• pp.3-9
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• 2007

Existing long range piezoelectric motors with friction based transmission mechanisms are limited by the axial load capacity. To overcome this problem, a new linear piezoelectric motor using one piezoelectric actuator combined with a novel stepping mechanism is reported in this paper. To obtain both long range and fine accuracy, dual positioning control strategy consisting of coarse positioning and fine positioning is used. Coarse positioning is used for long travel range by accumulating motion steps obtained by piezoelectric actuator. This is followed by fine positioning where required accuracy is obtained by fine motion displacement of piezoelectric actuator. This prototype is able to provide resolution of 20 nanometers and withstand a maximum axial load of 300N. At maximum load condition, the positioner can move forward to a travel distance of 5mm at a maximum speed of 0.4 mm/sec. This design of nanopositioner can be used in applications for ultra precision positioning and grinding operations where high axial force capacity is required.

• The Journal of Pediatrics of Korean Medicine
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• v.31 no.3
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• pp.24-36
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• 2017

Objectives The purpose of this study is to provide clinical evidence of herbal medicine treatment for cerebral palsy by reviewing randomized controlled trials conducted in China. Methods We searched literatures dated up to 17 May, 2017 in China National Knowledge Infrastructure (CNKI), and evaluated methodological quality of those studies using 'Risk of Bias' tool. Results Sixteen studies were selected for analysis. These studies indicated that the total effective rate, motor function, self-care, muscle spasticity were significantly improved in the herbal medicine treatment group, as compared to the control group. The most-commonly-used herbs were Poria (茯?), Astragali Radix (黃?), Glycyrrhizae Radix (甘草), and Atractylodis Rhizoma Alba (白朮). There were no serious adverse events found that were associated with herbal medicine treatment. The methodological quality of included studies was generally unclear or low. Conclusions This study shows that the herbal medicine treatment can be effective and safe in treating cerebral palsy. Further well-designed clinical trials with high methodological quality and appropriate assessment tools need to be performed to solidify these findings.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6090-6097
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• 2013

A pneumatically-driven driving simulator that provides a realistic representation of the driving environment was developed. The motion platform for the driving simulator is a mechatronic device that gives a driver the realistic feeling of an actual vehicle. The cost of the motion platform comprises the largest part of the expenses in developing a driving simulator. In this project, to develop a low-cost motion platform, the self-built motion platform based on the Stewart platform configuration that is constructed by six pneumatic cylinders was used as its actuator. The Stewart platform that moves in response to the operating signals of the joystick showed satisfactory tracking performance. We confirmed the possibility of the driving simulator using rFactor that is a commercially available racing game software.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.05a
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• pp.348-354
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• 1999

In recent years, a PID controller has been used as a major control method in real control processes. This controller requires a determination of PID control gains. But it is difficult to select the best gains theoretically. Thus there have been many approaches to determine them empirically Most of them are based on experience and knowledge. In this paper, we proposed a tuning method of the PID Parameters by using neural network. To show effectiveness of the proposed method, the simulation of DC motor and one link manipulator position control is carried out.