• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.8 no.4
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• pp.46-54
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• 1994

Exhbitlon hghting design be done aftrr due consideration of the photochermcal reaction and h ~ ~ i i tc~.fficits~ upn exposure to light. In this study the balanced judgement is as follows. The most light-susceptible material shouid be illu~stratrui less than 50[k] (illurnlnance-hours per year : 120, 000k.h)and the illuminance of moderately sensitive rriatcrinl k 200[1x] (illuminance hours per year : 480, 0001x.h). Moreover to minimize damage the sources of light shoulcl not only contribute as little as heat possible but remove ultraviolt radiation by filters. Also the sources of light must have good color rendering and low color temperature.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.1
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• pp.258-262
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• 2003

Background and Purpose : In the acute stage of stroke, many medical and neurological problems complicate and affect the clinical course of patients. according to previous reports. Although some of them may be predicted, few data exist about them. So we were to investigate the characteristics of complications in hospitalized patients due to stroke. Methods : We retrospectively examined the clinical notes of patients admitted in Won Kwang oriental medical hospital after stroke. Two observers inspected the clinical notes using predefined diagnostic criteria and recorded the type, timing, and frequency of complications that occurred during hospitalization. Results: Total 78 subjects were included in this study. Medical complications(88%) were more frequently complicated than neurological ones(65%). The most common medical complication was constipation(29%) followed by fever(28.2%) and overflow incontinence associated with dysuria(28%). The most common neurological complication was dysphagia(23.7%) and the second was agitation or Insomnia(36%) and the third was headache(21%). Conclusion : Complications after acute stroke were commonly observed. And There were more frequent medical complications than neurological ones. So we should have much knowledge about medical complications and treat them actively. The differences between our study and previous studies are attributable to the different methods including patient selection and diagnostic criteria.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.1
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• pp.113-120
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• 2016

This paper presents observer-based virtual sensors for YMC(Yaw Moment Control) systems by differential braking. A high-fidelity empirical model of the hydraulic unit in YMC system was developed for a model-based observer design. Optimal, adaptive, and robust observers were then developed and their estimation accuracy and robustness against model uncertainty were investigated via HILS tests. The HILS results indicate that the proposed disturbance attenuation approach indeed exhibits more satisfactory pressure estimation performance than the other approach with admissible degradation against the predefined model disturbance.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.251-260
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• 2015

The main purpose of this paper is to describe a DTC (direct torque control) method for four-switch brushless dc motor (BLDCM) drive. In the method, a novel voltage space vector modulation scheme, an optimal switching table, and a flux observation method are proposed. Eight voltage vectors are summarized, which are selected to control BLDCM in SVPWM pattern, and an optimal switching table is proposed to improve the torque distortion caused by midpoint current of the split capacitors. Unlike conventional flux observers, this observer does not require speed adaptation and is not susceptible to speed estimation errors, especially, at low speed. Global asymptotic stability of the flux observer is guaranteed by the Lyapunov stability analysis. DC-offset effects are mitigated by introducing a PI component in the observer gains. This method alleviates the undesired current and torque distortion which is caused by uncontrollable phase. The correctness and feasibility of the method are proved by simulation and experimental results.

• Journal of Digital Contents Society
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• v.12 no.4
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• pp.519-530
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• 2011

This study purposed to interpret subjectivity, which centers on the concept of virtuality embedded in the process of virtualizing contextual awareness and mixing the boundary between realities and virtual realities for renewing the feeling of time and space represented by augmented realities in daily spaces, from the viewpoint of traditional media. By explaining how the reflection of reality is exposed focusing on immediacy and hypermediacy from the viewpoint of media remediation, we found that, different from conventional media, augmented reality enables the screen to function as a part of subject and play a role and, by doing so, converts it to the complete subject of digital media comprehending observers and operators.

• ETRI Journal
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• v.37 no.2
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• pp.406-416
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• 2015

Timing plays a key role in expressing the qualitative aspects of a character's motion; that is, conveying emotional state, personality, and character role, all potentially without changing spatial positions. Temporal editing of locomotion style is particularly difficult for a novice animator since observers are not well attuned to the sense of weight and energy displayed through motion timing; and the interface for adjusting timing is far less intuitive to use than that for adjusting pose. In this paper, we propose an editing system that effectively captures the timing variations in an example locomotion set and utilizes them for style transfer from one motion to another via both global and upper-body timing transfers. The global timing transfer focuses on matching the input motion to the body speed of the selected example motion, while the upper-body timing transfer propagates the sense of movement flow - succession - through the torso and arms. Our transfer process is based on key times detected from the example set and transferring the relative changes of angle rotation in the upper body joints from a timing source to an input target motion. We demonstrate that our approach is practical in an interactive application such that a set of short locomotion cycles can be applied to generate a longer sequence with continuously varied timings.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.5
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• pp.402-410
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• 2004

To obtain a good tracking performance in an optical disk drive servo system, it is essential to attenuate periodic disturbances caused by eccentric rotation of the disk. As an effective control scheme for enhancing disturbance attenuation performance, disturbance observers (DOBs) have been successfully applied to the track-following servo system of optical disk drives. In disk drive systems, the improvement of data transfer rate has been achieved mainly by the increase of disk rotational speed, which leads to the increase of the disturbance frequency. Conventional DOBs are no longer effective in disk drive systems with a high-speed rotation mechanism because the performance of conventional DOBs is severely degraded as the disk rotational frequency increases. This paper proposes a new DOB structure for effective rejection of the disturbance in optical disk drives with a very high rotation speed. Asymptotic disturbance rejection is achieved by adopting a band-pass filter in the DOB structure, which is tuned based on the information on the disturbance frequency. In addition, performance sensitivity of the proposed DOB to changes in disk rotational frequency is analyzed. The effectiveness of the proposed DOB is verified through simulations and experiments using a DVD-ROM drive.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.6
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• pp.389-395
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• 2019

This paper presents the sensorless position control of an auxiliary scaffolding step system for vehicles using DC motors. The designed auxiliary scaffolding step has a mechanical protector at the stop position. At this position, the scaffolding is forcibly stopped by the mechanical protector, and the motor current is dramatically increased to the stall current of the DC motor, thereby increasing the electrical damage. In this study, the estimated back EMF- and current model-based observers are proposed to estimate the motor speed and stop position. A simple V/F acceleration voltage pattern is used to operate the auxiliary scaffolding system. The estimated moving position is adopted to determine the stop position of the DC motor with the load current state. The operating current of the DC motor can be reduced by the estimated moving position and V/F acceleration pattern. At the stop position, the proposed sensorless position controller can smoothly stop the DC motor with the estimated moving position and reduced load current without any mechanical and electrical stress from the stall current from the mechanical protector. The proposed control scheme is verified by the comparison of simulations and experiments.

• Korean Journal of Childcare and Education
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• v.13 no.5
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• pp.43-64
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• 2017

Objective: The purpose of this study was to develop and validate the Behavior Rating Scale for Preschool Children based on the Yonsei Open Education Curriculum. Methods: The subjects of the study were 145 children aged three to six attending a preschool affiliated with a university and their teachers. Teachers observed their children for at least two weeks and completed the Behavior Rating Scale for Preschool Children. The scale consisted of five areas and 44 items which was a five level rubric. Results: Results showed that age differences were significant and development trends were revealed in almost all items. Second, the mean between the upper and lower groups showed a significant difference. Third, the internal consistency reliability was .97 for all items and for the five areas ranged from .86 to .93. The inter-observers reliability was .84. Forth, the concurrent validity and content validity of the scale were relatively high. Conclusion/Implications: The Behavior Rating Scale for Preschool Children can be used as a valid and reliable instrument to assess preschool children's development.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.356-362
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• 2017

This paper presents a robust position controller for a one degree-of-freedom (DOF) mechanical system using only position measurement. In order to alleviate the performance degradation owing to various uncertainties, a two-stage design method is studied by employing a proportional integral observer (PIO). In the first stage, a baseline backstepping controller is designed for a nominal system without accounting for uncertainties. The PIO is developed for estimating both the velocity information for the backstepping controller and an equivalent input disturbance for a feedforward compensation using the estimated uncertainty. It is shown that the estimation errors with the proposed PIO can be made arbitrarily small in a finite time. If the system suffers from undesirable actuator nonlinearities, however, it might be necessary to estimate the velocity and the disturbance with different rates of convergence. The proposed method combines the predesigned backstepping controller and dual PIOs to reduce mechanical vibrations as well as steady-state errors. The performance of the proposed method is tested through comparative computer simulations and experiments using a laboratory prototype.