• Proceedings of the IEEK Conference
• /
• 2002.06e
• /
• pp.59-62
• /
• 2002

BLDC motor is widely used in automation areas for its good maintenance and controllability. In this paper it is designed for a speed control servo system of sinusoidal typo BLDC motor that can be easily adapted to automation systems with lower cost. Also, control parameters & periods are made adjustable according to the sensors of the motor, electric and mechanical time constant, and PI and PD control are used. The processor for the proposed system is a low cost 16bit One-Chip microprocessor. By experimental results from application to the industrial sewing machine, one of the application of BLDC motor, it can be verified that under the given reference, the system is enough as a speed and position servo without overshoots.

• Korean Journal of Child Studies
• /
• v.33 no.6
• /
• pp.21-34
• /
• 2012

This study examined the effects of physical activities using Korean dance upon the motor abilities of young children. The subjects of this study were divided into 2 groups. The first group was an experimental group (boy=12, girl=13) who participated in the Korean dance class and the other group was a comparative group (boy=11, girl=14). Experiments were performed during 18 sessions for 9 weeks. The study findings are as follows. First, physical activities using Korean dance had positive effects upon the development of basic motor abilities in young children. In terms of these basic motor abilities, movement motor ability and whole muscle operation motor ability showed significant differences between the pre-test and post-test stage in the experiment group and between the experimental and comparative groups in the post-test stage. On the other hand, in terms of non-movement motor abilities, there was a significant difference between the pre- and post-test stages for the experimental group, but no significant difference in the post-test stage for the experimental or comparative groups. Second, physical activities using Korean dance had positive effects upon the development of perceptive motor abilities in young children. In other words, in the sub-variables of perceptive motor abilities, there were significant differences between the pre- and post-test stages of the experimental group which experienced physical activities using Korean dance. In conclusion, the study findings showed that physical activities using Korean dance had positive effects upon the increase of both basic motor abilities and perceptive motor abilities in young children. Additionally, the experimental group exhibited more positive effects in the various areas of motor abilities than the comparative group.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09b
• /
• pp.804-805
• /
• 2006

Electric scroll-compressor drives are commonly used for e.g. home appliance cooling units. The recent development of hybrid cars with internal combustion engine in combination with electrical propulsion requires new solutions to be able to cool the passenger compartment of cars at stand-still. Both application areas demand efficient motor drives to reach good economy and efficient use of limited battery power as well as competitive volume/weight for a given output. The BLDC motor is a controllable and efficient solution. A major part of the motor is the soft-magnetic core. The powder based $Somaloy^{(R)}$ material shows high resistivity and induction as the result of engineered iron particles with in-organic coating. The unique features of compacted $Somaloy^{(R)}$ components can be utilized to enhance the shape and total volume of the BLDC motor with at least maintained efficiency compared to the use of traditional laminated steel sheet cores. A careful design of the $Somaloy^{(R)}$ components can also simplify assembly and positively influence the coil configuration. This study shows a comparison between a typical laminated BLDC motor and a redesigned, $Somaloy^{(R)}$ based version adapted for a scroll-compressor application.

• Physical Therapy Rehabilitation Science
• /
• v.11 no.1
• /
• pp.8-15
• /
• 2022

Objective: Post stroke motor recovery is facilitated by the brain reorganization or the neuroplastic changes. The therapeutic approach mentioned in the current case is one of the approaches for enhancing motor recovery by stimulating the damaged neural networks directing the motor behaviour of a person. The aim of the present study was to establish the changes in the balance and gait pattern of an individual through multi target stimulation of areas of cerebral cortex by utilising multichannel trans cranial direct current stimulation (M-tDCS) in a sub-acute stroke survivor. Design: A Case Report Methods: The present patient was the participant of the trial (CTRI/2021/02/031044).The patient was intervened with M-tDCS (anodes over left primary motor cortex that is C3 point and left dorsolateral prefrontal cortex i.e., F3 point and cathodes over supraorbital areas, Intensity - 1.2mA) for the duration of 20 minutes along with turbo med extern - an AFO to facilitate ankle dorsi flexion and conventional physiotherapy rehabilitation. The Fugl-Meyer assessment lower extremity (FMA-LE), Berg Balance Scale (BBS), Wisconsin Gait Scale (WGS) and the Stroke Specific Quality of Life (SSQOL) measures were used for outcome assessment. Baseline assessment was done on day 0 followed by assessment on 10 and 20 post intervention. Results: Improvement was seen in all the tools i.e. (FMA -LE), BBS, SSQOL and WGS over the time period of 20 days. Conclusions: M-tDCS resulted in improvement in gait parameters, balance and motor functions of lower extremity of the patient.

• Korean Journal of Child Studies
• /
• v.37 no.3
• /
• pp.83-93
• /
• 2016

Objective: This study examined that general characteristics such as gender, age, period of stay at an institution, size of facility, and temperament and attachment affect young children's development under institutional care. Methods: A total of 94 young children (ages 2-4years), who live in 32 institutions in Seoul were assessed on their development using the Korean-Age & Stage Questionnaire. Pearson productmoment correlation analysis, and multiple regression analyses were used for data analysis. Results: The major findings of this study were as follows: first, a longer period of stay at an institution had more positive effects on the development of communication. Facilities with more than 60 children had lower communication, gross motor, and fine motor development compared to facilities with less than 60 children. Second, social temperament had positive effects on communication, problem solving, and personal-social development. Emotional temperament had no effects on all development areas. Third, attachment had positive effects on all development areas. Lastly, social temperament and attachment had interactive effects on communication, gross motor, problem solving, and personal-social development. Conclusion: These results imply that caretakers in institutions should give developmental mediation services for considering temperament and facilitation of attachment.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2007.05a
• /
• pp.357-361
• /
• 2007

Transverse Linear Motor(TFLM) has been using in many areas of manufacture such as LCD, PDP construction and etc. However, the areas of TFLM application become wider, it needs a modification for new application. Above all, the conventional position estimation method is expensive in proportional to the length of the motor. Therefore, we need new position estimation algorithm using hall effect sensor.

• Korean Journal of Child Studies
• /
• v.27 no.4
• /
• pp.39-53
• /
• 2006

The Korean version of the Child Development Inventory (K-CDI) is a developmental screening test for children functioning in the one-six year range. Based on parent-report, the inventory assesses child developmental functioning in the areas of social, self-help, gross motor, fine motor, expressive language, language comprehension, letter and number skills, general development, and various symptoms and behavior problems. Participants were recruited from childcare centers and private groups and finally 1,143 children and their mothers from 4 locations nationwide participated in this study. Through analysis of item response rate of 270 items in 9 areas, new norm was formed. Reliability determined by internal consistency were relatively high (Cronbach ${\alpha}=.95$). Intercorrelations among sub-scales (range: .49-.96) indicated the construct validity, and the correlation between K-CDI and other screening tests supported the concurrent validity.

• Journal of Power Electronics
• /
• v.16 no.1
• /
• pp.1-8
• /
• 2016

Dead time is typically incorporated in voltage source inverter systems to prevent short circuit cases. However, dead time causes an error between the output voltage and reference voltage. Hence, voltage equation-based algorithms, such as motor parameter estimation and back electromotive force (EMF)-based sensorless algorithms, are prone to estimation errors. Several dead-time compensation methods have been developed to reduce output voltage errors. However, voltage errors are still common in zero current crossing areas, and an effect of the error is much worse in a low speed region. Therefore, employing voltage equation-based algorithms in low speed regions is difficult. This study analyzes the conventional dead-time compensation method and output voltage errors in low speed operation areas. A current shaping method that can reduce output voltage errors is also proposed. Experimental results prove that the proposed method reduces voltage errors and improves the accuracy of the parameter estimation method and the performance of the back EMF-based sensorless algorithm.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.57 no.1
• /
• pp.69-77
• /
• 2021

The noise environment was evaluated using the ISO recommended NR evaluation curve and PSIL (Preferred Sound Interference Level) in order to investigate the onboard educational environment according to the noise in the Motor Vessel Saehaerim, a fishing training ship under making way. As a result, NRNs were measured at 37-61 dB in accommodation areas, 44-56 dB in work areas, 37-57 dB in educational and conference areas, 83-103 dB in engine areas and 65.3 dB and 51.2 dB in the work and education areas respectively based on PSIL. The NRNs, which evaluated the cabin of the experimental ship according to the purpose, exceeded all of the indoor standard noise recommended by the ISO, and the PSIL had a generally short conversational distance within 0.25-2.3 m and 0.75-1.3 m for teaching and work areas.

• Journal of international Conference on Electrical Machines and Systems
• /
• v.3 no.4
• /
• pp.409-414
• /
• 2014

The parameters and operating characteristics of the switched reluctance motor (SRM) for the electric drive of the overland belt conveyor CLM-4500 have been presented. The motor power capacity has been equal to 1250 kW, the motor speed - 1000 min-1. SRM power supply has been provided by a three-phase voltage inverter and a 12-pulse rectifier circuit. The group electric drive has been installed on sections number 2 and 3, 3770 m and 3375 m length, respectively, on the areas of "Berezovsky Strip" JSC, a member of the Siberian Coal Energy Company.