• Proceedings of the Optical Society of Korea Conference
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• 2008.07a
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• pp.449-450
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• 2008

본 연구에서 우리는 4축 회전이 가능한 휘도측정기를 가지고 확산판 대신, PLF를 사용한 edge형 BLU의 광시야각, 휘도 및 스펙트럼을 측정하였다. 이에 따라, 우리는 조명설계 프로그램 'LightTools'을 이용하여 PLF와 프리즘 시트가 최적화 되도록 설계하여 분석하였다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.10
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• pp.44-49
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• 2021

Seats in autonomous vehicles must be able to rotate to fully utilize the interior space. Generally, ultra-high strength steel is used for the rotation module because it should have high strength and high rigidity. In addition, the rotating parts are difficult to form because they have complex shapes. In this study, the upper plate of the rotating module, whose complex shape makes it difficult to form, was formed by applying the hot stamping method. The drawing method and the form-drawing method, which are generally used to form components of complex shapes, were compared. We showed that the form-drawing method increased the degree of freedom of the material flow to improve the formability, thus enabling the forming of the plate. In addition, the die and blank shapes were found to be important factors in determining the success of the hot stamping. The validity of the analysis results was confirmed through forming analysis and experiments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.15-20
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• 2017

The main purpose of the ball valve ball is to be moved by the rotation of the stem when fully open or completely closed. In this study the heat of the initial model, which used a structure interaction analysis technique, tried to examine the structural safety of the high temperature for the ball valve. In the initial model the stress of the exiting sheet was more than the yield strength. We selected two design shapes with variables of length and thickness for the optimization of the sheet. The Kriging interpolation method was applied to a meta-model-based optimization technique. As a result, it was possible to find a thickness and length for the sheet within the yield strength. This was done by measuring the value of the capacity coefficient of the valve and evaluating the performance of the ball valve.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.2
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• pp.109-115
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• 2013

In this paper, we developed pressure mesuring system for powered wheelchair and tried to validate the usefulness of developed system by pressure measuring experiment with 3D motion analysis. This system consist of 64ch seat FSR(Force Sensitive Resistance) sensor unit, 30ch*2 armchair FSR sensor unit, analog and digital hardware board, 2ch rotary encoder unit and realtime signal processing & display S/W. And each data acquired from this system has sampling frequency of 12bit, 10Hz. Pressure measuring experiment for 10 persons who use wheelchair in real life was performed in the 3D vision analysis room. From the experiment, we obtained result that the center line of body inclined to outside direction during powered-wheelchair rotate any direction.

• Journal of the Society of Disaster Information
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• v.10 no.1
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• pp.1-14
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• 2014

This paper presents the three-dimensional stress analysis of orthotropic thick plates using the three-dimensional spline strip method based on the theory of elasticity. The orthotropic plates are made of Aragonite crystal and sitka spruce. To demonstrate the convergence and accuracy of the present method, several examples are solved, and results are compared with those obtained by other exact and numerical methods based on the theory of elasticity. Good convergence and accuracy are obtained. The effects of thickness/width ratio, aspect ratio and boundary conditions on normal stress distributions of Aragonite crystal plates and sitka spruce plates are investigated. Moreover, the difference of weak orthotropic and strong orthotropic properties given to the characteristics of stress distributions are also shown.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.4
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• pp.287-294
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• 2016

Based on upper limb torque by different angles of a back, distance between crank axis and chest and angles of hand-grips, this research is to develop variable hand bikes. By doing so, it is to offer guidance for its design. For this research three normal persons took part in the experiment. Results are as follows. First, upper limb torque was found to be the highest at 50 degree of a back and muscle endurance was shown to be the highest at 80 degree of a back. It means that as a back of a chair gets lower the speed and efficiency becomes better, which contradicts the subjective fact that K-type hand bikes would show the highest speed. Second, among types of grips of hand bikes 45 degree ones have been shown to be the ones with the highest torque. This is due to proper distribution of power of joints in arms, elbows, and shoulders. Third, in case of distance of 45cm between crank axis and chest, it has shown the most efficient torque. This is because of the effect of gravity and exhaustion when handling.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.851-860
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• 2020

With an increase in the aging population and a rising social interest in health and welfare, studies to improve healthcare in the elderly are being actively conducted. This study attempted to improve the current design and manufacture of elevating electric wheelchairs to enhance user safety and convenience. Seat design based on the user's body shape, convenience while boarding or alighting, caster turning radius and, safety and stability features that prevent shaking when the user gets up or sits down were improved. A driving experiment was conducted to evaluate the operation of the indoor electric wheelchair designed and manufactured with these additional functionalities. During the test, the performance parameters evaluated were continuous driving time, turning radius, maximum lifting and lowering load, maximum lifting height, noise level, minimum distance sensing by the driving auxiliary sensor, ability to interact with server and app programs, and the duty cycle maximum error rate. The test confirmed that this improved electric wheelchair successfully met target parameters. In a future study, we will evaluate this improved electric wheelchair from a user's perspective for its usability parameters, such as satisfaction, convenience and stability.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.5
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• pp.215-222
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• 2018

Recently, various motion beds have been actively developed and popularized. The motion bed has the functions of height adjustment, back plate rising, knee lifting, tilt function and left / right rotation, and the remote control can conveniently be used by the patient himself or the caregiver to move the patient. However, since the medical bed for use does not have a function of preventing pressure ulcers, exchanging sheets, and transferring patients, it is necessary to disperse body pressure by using a pressure ulcer prevention matrix to prevent pressure ulcers. However, it is accompanied by muscle strength and hard work, and nurses are avoiding difficult nursing care. In this study, we developed the first prototype in the world and confirmed that the system works normally with the goal of developing multifunctional beds that automatically perform the prevention of bed sores, the exchange of sheets and the transfer of patients in order to facilitate such nursing work. It is anticipated that the proposed multifunctional motorized bed in the future will be a model of a medical robot for smart healthcare.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.2
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• pp.209-222
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• 2011

Missing anterior teeth can be replaced using any of a number of methods. Patients may choose to replace missing teeth with a prosthesis that is either removable, fixed, or retained with implants. For patients faced with financial, anatomical, and/or esthetic limitations, the edentulous region can be restored successfully and esthetically with a properly designed and fabricated rotational path RPD. The rotational path RPD is a partial removable dental prosthesis that incorporates a curved, arcuate, or variable path of placement allowing one or more of the rigid components of the framework to gain access to and engage an undercut area. The rigid retainer must gain access to the infrabulge portion of the tooth by rotating into place. Either a minor connector or proximal plate provides retention through its intimate contact with a proximal tooth surface. A specially designed dovetails or asymmetric rest seats provides support and embracing effects. Correctly designed and fabricated rotational path RPD can provide improved esthetics, cleanliness, and retention. But rotational path RPDs are technique sensitive since the rotational path RPD has little margin of laboratory error that rigid retainers cannot be adjusted like conventional clasps can, RPD framework must be remade once the retention is lost. The sufficient understanding of the concept for the rotational path RPD is required for clinically successful treatment. This clinical report describes in detail the theoretical, laboratory considerations and the treatment of a patient with an anterior maxillary edentulous area treated by an AP path rotational RPD that had a difficulty in long term maintenance and describes another clinical case in which more reasonable treatment procedures were approached after analyzing the former case.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.415-424
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• 2019

In this paper, a minimum rotation radius was designed and fabricated to overcome the threshold so that elderly or disabled people who have difficulty moving can move and transfer safely and conveniently in a narrow room. In the indoor environment, where the sedentary culture develops, this study aimed to provide convenience for passengers with fracture diseases, geriatric diseases, and other knee and waist diseases. First, links, seats, armrests, covers, motors, batteries, chargers, controllers, etc. were attached to the frame so that they could be moved and lifted indoors. The product design and structure were designed considering the user's environment and physical characteristics, and IoT functions were added. A driving experiment was performed to confirm the operating performance of the manufactured indoor moving and lifting wheelchair. The performance tests, such as continuous running time, turning radius, maximum actuator load, maximum lift height, sound pressure level, minimum sensing distance of the driving aid sensor, interworking of server and app programs, device compatibility, and duty cycle error rate, were performed. As a result of the test, the built-in wheelchair could achieve the performance test target of each item and operate successfully.