• Current Applied Physics
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• v.18 no.11
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• pp.1447-1450
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• 2018

The electron spin resonance (ESR) detects point defect of the In-Ga-Zn oxide (IGZO) like singly ionized oxygen vacancies and excess oxygen, and get spin density as a parameter of defect state. So, we demonstrated the spin density measurement of the IGZO film with various deposition conditions and it has linear relationship. Moreover, we matched the spin density with the total BTS and the threshold voltage ($V_{th}$) distribution of the IGZO thin film transistors. The total BTS ${\Delta}V_{th}$ and the $V_{th}$ distribution were degraded due to the spin density increases. The spin density is the useful indicator to predict $V_{th}$ instability of IGZO TFTs.

• Journal of Information Display
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• v.2 no.3
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• pp.44-47
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• 2001

The extracted field emission current can be used to controllably heat microfabricated cold field emission cathode tips. The heating can be sufficient to smooth and recrystallize the tip surface by surface self-diffusion, and at least partially clean the surface of contaminants by thermal desorption. Self-heating not only allows for the achievement and maintenance of stable emission characteristics, but can be used to make the current-voltage characteristics of microfabricated field emitter tips nearly identical to one another. The resulting improvement in emission uniformity will allow for more reliable array operation at increased electron emission current densities.

• PNF and Movement
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• v.15 no.2
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• pp.149-157
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• 2017

Purpose: The purpose of this study was to assess the effect of using smartphones for tele-rehabilitation on head position and neck dysfunction in workers with visual display terminal (VDT) syndromes over a four-week period. Methods: Sixteen VDT workers volunteered to participate in stretch exercise and posture education sessions. The subjects were divided into three groups as follows: five subjects in the visit group (VSG), six subjects in the video group (VEG), and five subjects in tele-rehabilitation group (TG). The subjects in all the groups performed the exercises three days per week for four weeks. Cranial rotation angle (CRA), craniovertebral angle (CVA) measurement, and neck disability index (NDI) tests were performed before and four weeks after the intervention. Results: No significant difference in the CRA and CVA variables was found among groups. No significant difference in the CRA variable was found within each group. A significant difference in the CRA variable was found in the VSG after the four-week intervention. No significant difference in NDI was found among the groups. The NDIs among all the groups were significantly decreased after the intervention when compared with the NDIs measured before the intervention. Conclusion: The use of smartphones in the tele-rehabilitation of VDT workers with neck pain was found to be as effective on neck function as the conventional intervention method. The tele-rehabilitation of VDT workers with neck dysfunctions may be presented as an alternative way.

• The Journal of the Korea Contents Association
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• v.7 no.2
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• pp.84-91
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• 2007

Recently, the researches based on vision about user attention and action awareness are being pushed actively for human computer interaction. Among them, various applications of tabletop display system are developed more in accordance with touch sensing technique, co-located and collaborative work. Formerly, although supported only one user, support multi-user at present. Therefore, collaborative work and interaction of four elements (human, computer, displayed objects, physical objects) that is ultimate goal of tabletop display are realizable. Generally, tabletop display system designs according to four key aspects. 1)multi-touch interaction using bare hands. 2)implementation of collaborative work, simultaneous user interaction. 3)direct touch interaction. 4)use of physical objects as an interaction tool. In this paper, we describe a critical analysis of the state-of-the-art in advanced multi-touch sensing techniques for tabletop display system according to the four methods: vision based method, non-vision based method, top-down projection system and rear projection system. And we also discuss some problems and practical applications in the research field.

• Korean Journal of Computational Design and Engineering
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• v.15 no.3
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• pp.167-177
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• 2010

In recent years, the use of high-resolution tiled display system which does not have restrictions on the size of the screen and implements various layout of tile is increasing in order to evaluate the digital mock-up in physical scale or explore large engineering data set in detail. In this study, we developed multi-channel distributed visualization system which provides a virtual reality-based visual contents using 3D open-source graphics engine. Efficient data structures and exchange methods were proposed as a scene synchronization technology in PC cluster environments. DLP-Cube based tiled visualization system which provides $5{\times}2$ layout of display wall was developed and we validated our approach using this system. In addition, we introduced integrated control program that administrates PC cluster environment in remote and controls the layout of display channels.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.5
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• pp.445-450
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• 2005

In this paper, we suggest an integrated tactile display system that provides kinesthetic force, pressure distribution, vibration and slip/stretch. The system consists of two parts: a 2 DOF force feedback device for kinesthetic display and a tactile feedback device for displaying the normal stimulation to the skin and the skin slip/stretch. Psychophysical experiments measure the effects of fingerpad selection, the direction of finger movements and the texture width on tactile sensitivity. We also investigate the characteristics of lateral finger movement while subjects perceive different textures. From the experimental results, the principal parameters for designing a tactile display are suggested. A tactile display device, using eight piezoelectric bimorphs and a linear actuator, Is implemented and attached to a 2 DOF translational force feedback device to simultaneously simulate the texture and stiffness of the object. As a result, we find out that the capability of the suggested device is sufficient to display physical quantities to display the texture.

• Electronics and Telecommunications Trends
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• v.35 no.4
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• pp.65-80
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• 2020

In this article, we review the study trends of three-dimensional (3D) displays that can display stereoscopic images from the perspective of a display device. 3D display technology can be divided into light field, holographic, and volume displays. Light field display is a display that can reproduce the intensity and direction of light or 'ray' in each pixel. It can display stereoscopic images with less information than a holographic display and does not require coherence of the light source. Therefore, it is expected that it will be commercialized before the holographic display. Meanwhile, the holographic display creates a stereoscopic image by completely reproducing the wavefront of an image using diffraction in terms of wave characteristics of light. This technology is considered to be able to obtain the most complete stereoscopic image, and the digital holographic display using a spatial light modulator (SLM) is expected to be the ultimate stereoscopic display. However, the digital holographic display still experiences the problem of a narrow viewing angle due to the finite pixel pitch of the SLM. Therefore, various attempts have been made at solving this problem. Volumetric display is a technology that directly creates a stereoscopic image by forming a spatial pixel, which is known as a volumetric pixel, in a physical space, and has a significant advantage in that it can easily solve the problem of the viewing angle. This technology has already been tested for commercial purposes by several leading companies. In this paper, we will examine recent research trends regarding these 3D displays and near-eye display that is emerging as a significant application field of these technologies.

• Physical Therapy Rehabilitation Science
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• v.2 no.1
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• pp.7-11
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• 2013

Objective: Final goal of nerve advancement therapy is to provide maximum ability to function independently in life to patients. This paper appraises and describes basic concepts of the virtual reality (VR) based exercise program to improve functional movement for neurologically impaired patients. Design: Review article. Methods: Stroke patients from the physical therapy department while wearing comfortable clothing receive therapy and also VR based motion therapy administered by the therapist in charge. After evaluation of stroke patients, therapy includes an exercise program that is suitable for use with stroke patients; stroke patients wear head-mounted display while in front of the computer, where the camera is located; they follow the action on the screen and the computer perceives the operation of the stroke patients according to subject accomplishment. Results: According to obstacle condition of stroke patients using the method, which is various environments after setting, in stroke patients, there is a possibility of presenting suitable therapeutic environments. The display presentation of the method, which is identical, causes difficulty for all stroke patients. According to subject accomplishment; stroke patients result in execution of repetition training and deepening study, which leads to mobility. Conclusions: The VR based rehabilitation training programs is a difference of the existing video training program, is immediate feedback and compensation method. It will provide rehabilitation training services for the family of the patient whose condition could be improved with rehabilitative therapy where it is a continuous circumstance as a matter of the social welfare facility therapy.

• Proceedings of the Korea Contents Association Conference
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• 2006.11a
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• pp.616-621
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• 2006

Recently, the researches based on vision about user attention and action awareness are being pushed actively for human computer interaction. Among them, various applications of tabletop display system are developed more in accordance with touch sensing technique, co-located and collaborative work. Formerly, although supported only one user, support multi-user at present. Therefore, collaborative work and interaction of four elements (human, computer, displayed objects, physical objects) that is ultimate goal of tabletop display are realizable. Generally, tabletop display system designs according to four key aspects. 1)multi-touch interaction using bare hands. 2)implementation of collaborative work, simultaneous user interaction. 3)direct touch interaction. 4)use of physical objects as an interaction tool. In this paper, we describe a critical analysis of the state-of-the-art in advanced multi-touch sensing techniques for tabletop display system according to the four methods: vision based method, non-vision based method, top-down projection system and rear projection system. And we also discuss some problems and practical applications in the research field.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1561-1563
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• 2008

We report an optical second harmonic generation measurement that allows direct probing of dynamical carrier motion in organic field effect transistors. Carrier injection and transport process are discriminated. The mobility and contact resistance of pentacene FETs are determined from the visualized diffusion-like carrier motion.