• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.27 no.3
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• pp.1-15
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• 2021

Objective: The purpose of this study was to examine the differences in joint position sense (JPS), force sense (FS), and performance level of the upper extremities according to the injury and pain experiences of Korean elite archers. Methods: A total of 15 subjects were briefed about the purpose of this study and agreed to participate voluntarily. JPS was evaluated using the laser-point attached to the wrist while aiming at the target. The difference when relocating while aiming was used as JPS factor. FS was evaluated using load cell through reproduces same muscle strength. Fear-Avoidance Beliefs Questionnaire (FABQ) was used to evaluate psychosocial factors, Kerlan-Jobe Orthopedic Clinic overhead athlete scores (KJOC) and numerical rating scale (NRS) was used to evaluate pain. and performance was evaluated by tournament match score. Results: There is a strong correlation between the current pain and KJOC. Moreover, moderate correlation between KJOC and FABQ also current pain and both upper trapezius and lower trapezius in elite archers. The mean (SD) between groups based on current pain display relatively large margin in force sense than without pain group. The result presents that there is a significant difference in performance and pain. There is a significant difference in the force sense of the upper and lower trapezius and pain. Conclusions: Result present there is a significant difference in functional level in the average comparison between groups according to the presence of absence of current pain. There is a significant difference in the force sense of the upper trapezius as well as lower trapezius and without pain group present a relatively low joint position sense error compared to the groups.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.882-885
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• 2003

In this paper, we describe a haptic jacket and wheel as a haptic interface to enhance VR game realism. Building upon the VR game system using this devices, our haptic interface technique allows the user to intuitive interact on game contents, and then to sense the game event properties such as walking, attacking, driving and fire in a natural way. In addition, we extended the initial haptic model to support haptic decoration and dynamic interactions due to the added game event in a real time display. An application example presented here is a VR Dino-Attack game. This game supports interactions among dynamic and our intuitive haptic interface. Modeling physic interactions involves precise collision detection, real-time force computation, and high control-loop bandwidth.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.632-635
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• 2000

In this paper we propose a controllable interrupt timer for haptic control system. haptic control system whihc was divided ito two processes as virtual environment(VE) manager and haptic controller. The VE manager displays the 3D graphic scene at low update rates 25Hz and haptic controller controls the haptic display at high update rates 1000Hz. To archive the accurate update rate we have imple-mented a timer so called "AaccTimer" based on Windows multimedia functions, The proposed "Acc Timer" for haptic control system has been imple- mented in a personal computer with a 6-DOF haptic interface. Experimental results show that our system is robust with respect to tolerances in the control rates and also through the accurate control rate the operator can always feel a stable force.feel a stable force.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.5 no.2
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• pp.36-41
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• 2006

This study was carried out to install the lifting force of a two hinge type stand mechanism by 6 Sigma process in advance. This unit is designed for the display device in order to enhance the ergonomics for effective height adjustment and maintenance at any preferred position. The unit will be very useful for the mechanism fabricated with coil springs and disc springs as a torque generator. The 6 Sigma process was applied to select two key factors among 7 elements to lift the head unit and to find out applicable tolerance securing the 3.4 ppm of defects as well as what deviation of lifting force we can expect between calculation and experiment at the design stage of development. The result of this study can be applied to various units for the optimization of the smooth lift.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.564-568
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• 2006

Smooth picture module is operated by vibration to tilt the light from the DMD (digital micro mirror device) of DLP projection TV, which makes the screen of the TV smoother and DMD chip cost lower. To satisfy the vibration characteristics of smooth picture module, it is designed by optimizing moment of inertia, spring constant and damping coefficient, using structural and fluid dynamic simulation that showed a good agreement with experimental data. To reduce the material cost and moment of inertia, engineering plastic is used and the reliability is estimated. A VCM (voice coil motor) type actuator for smooth picture has to satisfy performance requirements such as higher driving force, lower power consumption, and lower cost. The initial design and optimization for VCM was performed using FE analysis. It allowed us to optimize the design of magnetic circuit of the proposed actuator to obtain higher force while maintaining a lower cost.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.539-542
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• 2003

We have studied cell gap-dependent electrode-optic characteristics of the FFS mode using the LC with negative dielectric anisotropy. In case of a small cell gap of 2 ${\mu}m$, the transmittance at the center of pixel and common electrodes is low due to stronger influence of surface anchoring that holds the LC to the initial state than twisting force induced by neighboring LCs. In case of a large cell gap of 4 ${\mu}m$, the influence of surface anchoring force becomes weak so that the LCs at the center of pixel and common electrode can be twisted enough by applied voltage, giving rise to high transmittance. Therefore, we conclude that the light efficiency in the device is dependent on the cell gap.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.11
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• pp.915-919
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• 2011

We analyzed various forces affective to the charged particles in closed space, to explain the image degradation and lifetime-shortening phenomena because of particle lumping which is one of the serious problems in reflective displays. It is possible to predict the quantity of q/m which is the most important parameter in determining the optical and electrical characteristics, by calculating the image force and kinetic energy. For stable driving, the quantity of q/m must be in the defined range but it changes during the fabrication process, so we added the filtering process to solve this problem and obtained the well-defined nonlinear driving voltage coinciding with the threshold voltage. And we obtained the fully-driving property which prevents the particle lumping and decides the image quality and lifetime of panel from the optical characteristics and occupation surface of moving particles.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.3
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• pp.105-110
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• 2020

Alumina, a typical ceramic material used for semiconductors and display parts, is the subject of research and development efforts for mineral material processing. Alumina is extremely difficult to process since it is brittleness to either fine ceramics material. We have studied the shape of diamond particles and their use in machinability for alumina processing. Our study was carried out under various processing conditions, including cutting speed, table speed, and the surface roughness of the work piece. We also analyzed the wear characteristics of the tool by total cutting.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.55-58
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• 1996

A new type CuN/Cu/CuN thin film electrode material with high adhesion to glass was developed by the dc reactive planar magnetron sputtering system for the PDP(Plasma Display Panel). The adhesive force of the CuxN thin film was in the range of 20∼40(N) under the conditions of the N$_2$ partial pressure of 15%, discharge current of 70mA, discharge voltage of 450v and substrate bias voltage of -100V. The adhesive force was depended on the N$_2$ partial Pressure, discharge current and substrate bias voltage.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1459-1461
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• 2009

In this study, we prepared the multi-refraction film thin by ink-jet technique with sol-gel precursor. The precursors were prepared by using some transition metal alk-oxide and the tetraethylorthosilicate (TEOS) mixed separately with n-Butyl Alcohol and PVB (Poly(vinyl butyral)).The structure and morphology of the resulting films were investigated by atomic force microscope (AFM). It is shown that the shape of the pattern of the films would affect the refraction proportion.