• Journal of Institute of Control, Robotics and Systems
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• v.11 no.5
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• pp.451-456
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• 2005

This paper describes three kinds of experiments and analysis of their results related to human tactile sensitivity using an integrated tactile display system. The device can provide vibration, normal pressure and lateral slip/stretch which are important physical quantities to sense texture. We have tried to find out the efficient method of stimulating, limitation of surface discrimination by kinesthetic farce feedback and the effectiveness of the combination of kinesthetic force and tactile feedback. Seven kinds of different stimulating methods were carried out and they are single or combination of the kinesthetic force, normal static pressure, vibration, active/passive shear and moving wave. Both prototype specimen and stimulus using tactile display were provided to all examinees and they were allowed to answer the most similar sample. The experimental results show that static pressure is proper stimulus for the display of micro shape of the surface and vibrating stimulus is more effective for the display of fine surface. And the sensitivities of active touch and passive touch are compared. Since kinesthetic force feedback is appropriate to display shape and stiffness of an object, but roughness display has a limitation of resolution, the concurrent providing methods of kinesthetic and tactile feedback are applied to simulate physical properties during touching an object.

• Korean Journal of Materials Research
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• v.27 no.1
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• pp.43-47
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• 2017

E (Electric) -glass fibers are the most widely used glass fibers, taking up 90 % of the long glass fiber market. However, very few papers have appeared on the physical characteristics of E-glass fibers and how they depend on the fiberizing temperature of fiber spinning. Glass fiber was fabricated via continuous spinning process using bulk E-glass. In order to fabricate the E-glass specimen, raw materials were put into a Pt crucible and melted at $1550^{\circ}C$ for 2hrs; mixture was then annealed at $621{\pm}10^{\circ}C$ for 2hrs. The transmittance and adaptable temperature for spinning of the bulk marble glass were characterized using a UV-visible spectrometer and a viscometer. Continuous spinning was carried out using direct melting spinning equipment as a function of the fiberizing temperature in the range of $1175{\sim}1250^{\circ}C$, while the winder speed was fixed at 500 rpm. Subsequently we investigated the physical properties of the E-glass fiber. The average diameter of the synthesized glass fiber was measured by optical microscope. The mechanical properties of the fiber were confirmed using a UTM (universal materials testing machine); the maximum tensile strength was measured and found to be $1843{\pm}449MPa$ at $1225^{\circ}C$.

• The Journal of Korean Physical Therapy
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• v.31 no.5
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• pp.273-278
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• 2019

Purpose: The purpose of this study was to investigate the effects of three-dimensional virtual reality horse riding simulator training using a head-mounted display on gait and balance in children with cerebral palsy. Methods: Ten children with cerebral palsy were randomly assigned to the horse riding simulator (HRS) group (n=5) or the horse riding simulator with virtual reality (HRSVR) group (n=5). To evaluate balance, center of gravity (COG) sway velocity and total sway distance of each group were assessed using the Wii balance board, and gait speed and stride length of each group were assessed using a gait analysis system. Results: Intra-group comparisons between pre- and post-intervention measures revealed that there were significant changes in all gait and balance variables such as stride length, gait velocity, COG sway velocity and COG sway distance in the HRSVR group (p<0.05). In the HRS group, there were significant changes in all variables except stride length (p<0.05). In addition, inter-group comparisons showed significant differences between the two groups in stride length, gait velocity and COG sway distance except COG sway velocity (p<0.05). Conclusion: The findings of this study suggest that horse riding simulator training combined with 3D virtual reality can be a new positive therapeutic approach for improving functional performance in children with cerebral palsy.

• Journal of the Ergonomics Society of Korea
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• v.5 no.2
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• pp.37-44
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• 1986

This study investigates display station physical adjustments preferred by a sample of visual display terminal operators. Participants in the study were selected to assure representation of extremely short and extremely tall persons, as well as persons of midrange physical stature. Individual operators were led through a step-by-step sequence to determine their preferred initial settings of seat height, keyboard height and slope angle, and CRT height and tilt angle. Each operator then performed a brief text input tase, after which final preferred adjustments were measured. Intermeasure correlation strongly suggest that "flat" (low slope angle) keyboards are in appropriate for short operators who select low seat heights. In addition, the keyboard angle adjustments preferred by most operators substantially exceed a current German ergonomic display station requirement.

• Journal of the Korean Physical Society
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• v.73 no.9
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• pp.1329-1333
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• 2018

We investigated the mechanism of mobility enhancement after the dehydrogenation process in polycrystalline silicon (poly-Si) thin films. The dehydrogenation process was performed by using an in-situ CVD chamber in a $N_2$ ambient or an ex-situ furnace in air ambient. We observed that the dehydrogenated poly-Si in a $N_2$ ambient had a lower oxygen concentration than the dehydrogenated poly-Si annealed in an air ambient. The in-situ dehydrogenation increased the (111) preferred orientation of poly-Si and reduced the oxygen concentration in poly-Si thin films, leading to a reduction of the trap density near the valence band. This phenomenon gave rise to an increase of the field-effect mobility of the poly-Si thin film transistor.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.23-28
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• 2007

This article discusses physical processes affecting the speed of addressing discharge, and ways to both significantly increase the speed, and lower the cost of addressing.

• Journal of Korea Multimedia Society
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• v.12 no.5
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• pp.708-716
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• 2009

Applications which are implemented on Table Top Display are controlled by hands, so that they support an intuitive interface to users. Users feel the real sense when they interact on the virtual scene in Table Top Display. However, most of conventional augmented reality applications on Table Top Display satisfy only visual sense. In this paper, we propose an interface that supports multi-modal sense in that tactile sense is utilized for augment reality by vibrating a physical control unit when it collides to virtual objects. Users can feel the collision in addition to visual scene. The proposed system facilitates tactile augmented reality through an air hockey game. A physical control unit vibrates when it receives virtual collision data over wireless communication. Since the use of tabletop display environment is extended with a tactile sense based physical unit other than hand, it provides a more intuitive interface.

• Journal of Korean Physical Therapy Science
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• v.11 no.4
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• pp.20-28
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• 2004

The studys purpose were the effects of work posture, treatment method and prevention for Video Display Terminal(VDT) workers in Work-Related Musculoskeletal Disorders(WMSD) The results were as follows: 1. The prevalence rate of VDT workers in WMSD was $20{\sim}40%$. The complaint was mostly shoulder, neck, and hack area pain 2. VDT worker used to forward flexed posture and then affect of increase of muscle fatigue and pain 3. When exercise therapy PT and ADL training, were used workers decrease in pain, muscle strength, balance training, endurance strength and relief of psychiatricIn conclusion, VDT worker need good health and posture to rest and exercise with time space and treatment. It is best to prevent WMSD. VDT workers need health management by itself and systemic rehabilitation program by speciality therapist.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.303-306
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• 2007

Recent studies in the literature have shown that it is possible to overcome the limitations of the physical properties of liquid crystals by the doping of carbon nanotubes. Although still in its infancy, the potential of such a new approach for opportunities in display applications should not go unnoticed.

• Journal of Information Display
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• v.10 no.3
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• pp.101-106
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• 2009

In this study, a physical OLED analog behavior model for SPICE simulation was described using the Verilog-A language. The model was presented through theoretical equations for the J-V characteristics of OLED derived according to the internalcarrier emission equation based on a diffusion model at the Schottky barrier contact, and the mobility equation based on the Pool-Frenkel model. The accuracy of this model was examined by comparing it with the results of the device simulation that was conducted.