• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.5
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• pp.297-304
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• 2000

The motor for torpedo propulsion is needed the compact and short rating high power characteristics. This paper describes the development of the motor through the theory and Finite Element Method(FEM) analysis for Brushless Direct Current Motor(BLDCM) of 7 phase 6 poles. Back EMF, inductance and eddy current loss were analyzed. The proposed methods like magnetic wedge acquired by these FEM analysis were introduced. Phase-leading angle using encoder was used. Test results on the motor of 7 phase 6 poles were showed the validity of proposed methods and phase-leading angle.

• Korean Journal of Applied Biomechanics
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• v.32 no.3
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• pp.87-93
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• 2022

Objective: The purpose of this research was to investigate the age-related changes in whole-body motor variability during sit-to-stand (STS) task. It has been reported that children perform motor tasks less accurately with greater variability as compared to adults. However, it is still unknown how they utilize the abundant degrees of freedom and accomplish voluntary actions. Uncontrolled manifold (UCM) analysis has been used to partition motor variabilities into two independent variability components, task-relevant variability (V_ORT) and task-irrelevant variability (V_UCM). We investigated what differences exist between children and adults with respect to these two motor variability components in relation to motor development stages. Method: Ten 6-year-old children (height: 116.2 ± 4.3 cm, weight: 23.1 ± 3.9 kg, motor development assessment percentile score: 77.5 ± 18.6%), ten 10-year-old children (height: 138.7 ± 7.2 cm, weight: 35.8 ± 10.3 kg, motor development assessment percentile score: 73.9 ± 12.7%), and ten young adults (age: 23 ± 1.6 year-old, height: 164.3 ± 11.4 cm, weight: 60.8 ± 12.0 kg) participated in this study. Each participant performed STS ten times, and a motion capture system was used to capture the whole-body kinematics. Each segment centers of mass and the whole-body center of mass were calculated, and UCM analysis was used to quantify motor variabilities, V_ORT and V_UCM. One-way ANOVA was used for statistical analysis. Results: We found that children produced more motor variabilities in V_ORT and V_UCM in all three dimensions, anterior-posterior, medial-lateral, and vertical. As age increased, both, V_ORT and V_UCM significantly decreased (p<.05). Conclusion: The greater V_ORT found in children compared to adults indicates that the repeatability over repetitions improves through development, while the greater V_UCM found in children suggests that children better utilize the abundant degrees of freedom during STS compared to adults.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.189-192
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• 2010

In this study, insensitive munitions(IM) policies and technologies of advanced countries for solid rocket motor were investigated. Development trends and caseworks of each part such as propellant and motor case of rocket motor for IM were also studied. Based on these investigation and analysis for IM rocket motor, directions of the development for IM rocket motor in our country were suggested.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.3
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• pp.130-135
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• 2014

In this paper, a new estimation method is proposed to calculate steering rack axial force using a 3 dimensional tire mesh model when a car is standing on the road. This model is established by considering changes of camber angle and contact patch between the tires and the ground according to steering angle. The steering rack bar axial force is estimated based on the static equilibrium equations of forces and moments. A tire friction force is supposed to act on the center point of the contact patch, and the proportional coefficient of friction depending on contact patch is suggested. Using the proposed estimation method, rack axial force sensitivity analysis is evaluated according to changes of suspension geometry. Then optimal motor power of Motor Driven Power Steering(MDPS) is evaluated using suggested rack forces.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.3
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• pp.327-332
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• 2015

Educational robot was introduced as an effective educational tool is to foster scientific creativity and learn the basic principles of science are applied to change the configuration of the educational after-school learning kits for science education. SMEs as a tool to foster scientific creativity center and a variety of educational robot technology and the wide range of games for students and robotic technology development, existing e-Learning by downloading mp3 music or learning content for the robot, such as the provision of specialized content Although the technology is still being developed to take advantage of the professional community formation is insufficient side. Currently, one-point linkage drag Smart Touch control dynamic motor development does not need this motor development is possible for users to easily.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.4
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• pp.520-526
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• 2011

In recent years, it is very important that hydrogen storage system is safe for user in any circumstances in case of crash and fire. Because the hydrogen vehicle usually carry high pressurized cylinders, it is necessary to do safety design for fire. The Global Technical Regulation (GTR) has been enacted for localized and engulfing fire test. High pressure hydrogen storage system of fuel cell electrical vehicles are equipped with Thermal Pressure Relief Device (TPRD) installed in pressured tank cylinder to prevent the explosion of the tank during a fire. TPRDs are safety devices that perceive a fire and release gas in the pressure tank cylinder before it is exploded. In this paper, we observed the localized and engulfing behavior of tank safety, regarding the difference of size and types of the tanks in accordance with GTR.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.11
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• pp.3032-3038
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• 1994

The paper discusses a combustion instability phenomena encountered in recent solid rocket motor development efforts at ADD(Agency for Defense Development). It has happened to occur as an irregular burning in development of smokeless propellant rocket motor. Through investigating the spectral analysis of accelerometer and strain gage signals which are recorded in static firing tests and acoustic modal analysis of motor inside cavity with ANSYS, the instability is found to be the second tangential mode.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.2
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• pp.455-460
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• 2010

The high-efficiency induction motor reduces the generation loss of conventional induction motors and saves energy with less electricity consumed, enabling the return of initial facilities investments on a shorter-term basis due to its low operation cost and allowing the extension of the life of the motor. Poscore has entered the phase of development of high-efficiency induction motor based on its experiences to date in cooperation with electricity researchers. This paper examines the development of the small motor die for the high-efficiency induction motor.

• Journal of Korean Physical Therapy Science
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• v.8 no.1
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• pp.799-811
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• 2001

The purpose of this study was to examine the effects of sensory integration therapy (SIT) on gross motor development and respiratory function of cerebral palsy children. The design of this study was one-group pre-and post-test design. Subjects of the study were arbitrarily chosen based on predetermined selection criteria among the cerebral palsy children who were treated as out-patients at one rehabilitation hospital in Kyunggi-do. The study was conducted between early April and late July in 2000. Twelve children were in the experimental group. A five-step SIT program was devised from a combination of SIT programs suggested by Ayres(1985) and Fink(1989), and an author-designed SIT program for cerebral palsy children. The experimental group was subjected to 20 to 30 minutes of SIT per session, two sessions a week for ten-week period. Collected data were statistically analyzed by SPSS PC for Wilcoxon signed rank test, and paired t-test. The results were as follows: 1. In gross motor development, post-experimental gross motor scores were higher compared to pre-experimental scores with statistical significance. 2. In respiratory function, post-experimental forced capacity vital scores were higher compared to pre-experimental scores with statistical significance. In conclusion, SIT was found to be effective in gross motor development and respiratory function. But, for the more effectiveness of SIT on gross motor development and respiratory function, further studies employing longer-time experiments are recommended.

• Science of Emotion and Sensibility
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• v.20 no.1
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• pp.41-48
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• 2017

This study was conducted to develop wearable products with visual and auditory feedback aimed at promoting exercise interest in children. Here we determined the theoretical characteristics of cognitive and motor function development during childhood, empirical characteristics of children's motor functions, and factors that encourage exercise using natural observation and in-depth interview research methods. The questionnaire assessed children's motor ability, intensively trained body parts in sports programs, types of training or classes that improve the motor ability of each muscle group, significantly considered aspects of children's sports programs, and factors that promote children's interest in exercise. Our results suggest that the development of sport programs comprising varied exercise options that enhance body and limb movements are needed for balanced growth. Furthermore, it is very important to provide motivation for regular exercise and appropriate feedback, such as praise and encouragement, to maintain interest in exercise. This study identifies the standards for developing products that peak children's interest in exercise and the basis for a physically and mentally healthy society.