• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.181-188
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• 2024

With the development of precision facility technology, the importance of four-axis CNC precision processing technology is increasing. However, due to complex shape processing, it is difficult to operate the system. This paper compared precision control and efficiency by manufacturing a four-axis control structure to solve this problem and implementing Bresenham's Line Algorithm and Runspeed Algorithm without using commercial programs. When Runspeed was applied, there was an error improvement of about 12.03% and curvature accuracy improvement compared to Bresenham. It was confirmed that precise processing was possible to a three-dimensional structure by driving a rotary shaft A motor.

• Journal of Wellbeing Management and Applied Psychology
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• v.7 no.1
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• pp.51-65
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• 2024

Purpose: This study is to propose the establishment and direction of a public health-medical cooperation system for rehabilitation medical services for people with physical and brain disabilities in Gangneung, Korea. Research design, data and methodology: The study focused on 30 individuals with these disabilities registered. Data was collected from December 20, 2021, to December 31, 2021, through structured surveys administered by researchers visiting disability-related facilities, utilizing convenience and random sampling methods. Descriptive statistics and cross-analysis were applied for analysis. Results: Specifically, among respondents with physical disabilities, a total of 20 needs were identified, with 'Visiting health services' (25.0%) and 'Oral health services' (20.0%) ranking highest. The survey results regarding visit-based rehabilitation services for disability support showed a high demand, emphasizing the necessity of service provision tailored to the needs of recipients, focusing on disability prevention, health management, and motor function recovery, rather than solely medical or therapeutic concepts. Conclusions: Gangwon National University Hospital, as the regional referral hospital in Gangwon, should collaborate with Gangwon Province Rehabilitation Hospital to provide prompt acute rehabilitation services. Moreover, cooperation and collaboration with Gangneung Asan Hospital, the tertiary hospital in the region, are essential to ensure continued acute and recovery phase rehabilitation therapy for a certain period in the Gangneung area.

• The Journal of Korea Robotics Society
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• v.19 no.1
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• pp.53-57
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• 2024

A hopping robot can move through a confined environment while overcoming obstacles. To create a small hopping robot, it must be able to generate a large amount of energy and release it at the same time. However, due to the small size of the robot, there is a limit to the size of the actuator that can be used, so it is mainly used to collect energy in an elastic element and release it at once. In this paper, we propose a small hopping robot with a simplified design by removing ancillary parts and enabling continuous hopping using only a small actuator based on a direct-drive method. In addition, repeated actuation over the rated voltage can cause thermal breakdown of the actuator. To check the safety of the actuator at high voltage, we perform modeling to predict the temperature of the actuator and verify the accuracy of the modeling through experiments.

• Journal of Veterinary Clinics
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• v.41 no.1
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• pp.1-7
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• 2024

The intervertebral disc is a crucial structure located between each vertebral body, except C1 and C2 and the fused sacral vertebrae, which provides cushioning and stability. However, sometimes these discs may bulge or extrude, causing painful conditions and various neurological problems such as ataxia, paresis, motor or sensorimotor paralysis. As a result, dogs affected by intervertebral disc disease (IVDD) can suffer a significant decrease in their quality of life. The main objective of this study was to provide comprehensive data on the body size of several IVDD-susceptible dog breeds commonly bred in South Korea, which could help develop supportive devices for IVDD patients. Using standardized measurements, the study aimed to design appropriate support tools, taking into account the mobility challenges faced by IVDD patients. The findings provide valuable data to improve the quality of life of patients with IVDD. In addition, it may lay the foundation for research to establish the correlation between body size and IVDD through future research.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.5
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• pp.509-515
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• 2014

At the fuel processing system (FPS) of fuel cell vehicle, hydrogen recirculation blower (HRB) is used for the recirculation of remained hydrogen after reaction. In this paper, noise and vibration improvement of HRB is studied by changing design and control. It is checked the campbell diagram and critical speed for stability of rotor, and housing stiffness is improved using simulation of frequency response function (FRF). A method is suggested that can decrease the unbalance amount of the rotor and impeller which main source of noise and vibration. In order to reduce the noise during deceleration of blower, electrical braking is applied and tested the risk impact of durability. Founded the optimum switching frequency of the motor control, and reduced the idle rpm by increasing of aerodynamic performance. The superiority of paper is proved by measurement of the improved product's noise and vibration.

• Journal of the Korean Society of Combustion
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• v.19 no.4
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• pp.14-20
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• 2014

In the present study, an annular combustor for a 500 W class micro gas turbine generator was designed and its characteristics were investigated by using both numerical and experimental methods. For this purpose, geometrical configurations of the annular combustor were determined in the aspect of the aerodynamic and chemical consideration. Also, fluid flow and pressure drop characteristics in the combustor were numerically studied by using commercial tool, FLUENT. Based on the numerical results, the diameter and the angle of air admission holes in the primary zone were chosen to be 2.5 mm and $30^{\circ}$, respectively. Finally, an integrated test unit, which consisted of a compressor, combustor, turbine, and motor/generator, was developed in order to measure the combustor efficiency. As the temperature difference between the combustor inlet and the turbine inlet or the air mass flow rate increased, the combustor efficiency increased and it was over 90% when the air mass flow rate was larger than 7.30 g/s. It was shown that the annular combustor developed in this study met the design requirement for a 500 W class micro gas turbine generator.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.5
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• pp.570-577
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• 2014

This paper describes the design of a force applying system for a smart phone curved glass molding system and its characteristic test. The force applying system is composed of a motor and gear, a rectilinear movement structure, a force sensor, an LVDT (Linear Variable Differential Transformer) sensor, an up and down moving block, and so on. The system precisely controls the applying force and time to the plane glass because the glass can be easily destroyed under applied force, and can be bent imperfectly. As a result of the characteristic test, the curved glass can be manufactured using this system, and the holding time under 0N force, the applying force to the plane glass, the time for applying from 0N to maximum force, and the holding time under maximum force at the manufacture feasible temperature $620^{\circ}C$ were found.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5397-5402
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• 2012

Accidents involving electric equipment and economical loss by power quality deterioration related to harmonics show a rising tendency A passive filter is economic and efficient in suppressing harmonics but many engineers and designers are reluctant to install a passive filter to defect harmonics at their power system because of problems such as harmonic amplification and the probability of generating series or parallel resonance with the power system. This work introduces that passive filters will be very available to defeat harmonic problems of the power system if passive filters are well designed. We describe method and process of harmonic passive filter design. And the passive filter for the power system having harmonic problems due to use of nonlinear loads like as 100HP DC motor system, an extruding machine, an air blower and other loads are designed. Experimental results verify the performance of the passive filter designed by the described method and procedure.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.1
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• pp.61-69
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• 2015

The objective of this study is to experimentally investigate the mixed flow behaviors and oxygen transfer characteristics of a vertical orifice ejector. The experimental apparatus consisted of an electric motor-pump, an orifice ejector, a circulation water tank, an air compressor, a high speed camera unit and control or measurement accessories. The mass ratio was calculated using the measured primary flow rate and suction air flow rate with experimental parameters. The visualization images of vertically injected mixed jet issuing from the orifice ejector were qualitatively analyzed. The volumetric oxygen transfer coefficient was calculated using the measured dissolved oxygen concentration. At a constant primary flow rate, the mass ratio and oxygen transfer coefficient increase with the air pressure of compressor. At a constant air pressure of the compressor, the mass ratio decreases and the oxygen transfer coefficient increases as the primary flow rate increases. The residence time and dispersion of fine air bubbles and the penetration of mixed flow were found to be important parameters for the oxygen transfer rate owing to the contact area and time of two phases.

• Journal of Mechanical Science and Technology
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• v.20 no.12
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• pp.2147-2158
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• 2006

The continuous wavelet transform (CWT) has a frequency-adaptive time-frequency tiling property, which makes it popular for the analysis of dispersive elastic wave signals. However, because the time-frequency tiling of CWT is not signal-dependent, it still has some limitations in the analysis of elastic waves with spectral components that are dispersed rapidly in time. The objective of this paper is to introduce an advanced time-frequency analysis method, called the dispersion-based continuous wavelet transform (D-CWT) whose time-frequency tiling is adaptively varied according to the dispersion relation of the waves to be analyzed. In the D-CWT method, time-frequency tiling can have frequency-adaptive characteristics like CWT and adaptively rotate in the time-frequency plane depending on the local wave dispersion. Therefore, D-CWT provides higher time-frequency localization than the conventional CWT. In this work, D-CWT method is applied to the analysis of dispersive elastic waves measured in waveguide experiments and an efficient procedure to extract information on the dispersion relation hidden in a wave signal is presented. In addition, the ridge property of the present transform is investigated theoretically to show its effectiveness in analyzing highly time-varying signals. Numerical simulations and experimental results are presented to show the effectiveness of the present method.