• Proceedings of the Optical Society of Korea Conference
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• 2004.07a
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• pp.94-95
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• 2004

• Journal of Information Display
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• v.1 no.1
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• pp.9-13
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• 2000

In liquid crystal displays, the display mode that represents initial liquid crystal alignment and method of applying voltage, mainly determines the image quality of display. Recently we have developed the fringe-field switching (FFS) mode exhibiting high image quality. In this paper, a pixel concept, manufacturing process, materials, and electro-optic characteristics of the FFS mode comparing with conventional in-plane switching mode, and its possible application to reflective type are discussed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.11
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• pp.3955-3966
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• 2014

With the exponentially increasing Internet traffic and emergence of more versatile and heterogeneous applications, the design of datacenter networks (DCNs) is subject to unprecedented requirements for larger capacity and more flexible switching granularities. Envisioning Optical-Orthogonal Frequency Division Multiplexing (O-OFDM) as a promising candidate for such a scenario, we motivate the use of O-OFDM as the underlying switching technology in order to provide sufficient switching capacity and elastic bandwidth allocation. For this purpose, this article reviews the recent progresses of DCN deployment and assesses the scenario where the O-OFDM transmission and switching technology is employed in the underlying transport plane. We discuss the key issues of the datacenter-oriented O-OFDM optical networks, and in particular, elaborate on a number of open issues and solutions including system interconnection architecture, routing and resource assignment, survivability, and energy-efficiency.

• Journal of Mechanical Science and Technology
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• v.19 no.3
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• pp.778-791
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• 2005

A novel pneumatic artificial muscle actuator (PAM actuator), which has achieved increased popularity to provide the advantages such as high strength and high power/weight ratio, low cost, compactness, ease of maintenance, cleanliness, readily available and cheap power source, inherent safety and mobility assistance to humans performing tasks, has been regarded during the recent decades as an interesting alternative to hydraulic and electric actuators. However, some limitations still exist, such as the air compressibility and the lack of damping ability of the actuator bring the dynamic delay of the pressure response and cause the oscillatory motion. Then it is not easy to realize the performance of transient response of pneumatic artificial muscle manipulator (PAM manipulator) due to the changes in the external inertia load with high speed. In order to realize satisfactory control performance, a variable damper-Magneto­Rheological Brake (MRB), is equipped to the joint of the manipulator. Superb mixture of conventional PID controller and a phase plane switching control method brings us a novel controller. This proposed controller is appropriate for a kind of plants with nonlinearity, uncertainties and disturbances. The experiments were carried out in practical PAM manipulator and the effectiveness of the proposed control algorithm was demonstrated through experiments, which had proved that the stability of the manipulator can be improved greatly in a high gain control by using MRB with phase plane switching control method and without regard for the changes of external inertia loads.

• Transactions of The Korea Fluid Power Systems Society
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• v.1 no.1
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• pp.17-22
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• 2004

The goal of this paper is to improve the position control performance of pneumatic rotary actuator with variable brake using Magneto-Rheological Fluid. The air compressibility and the lack of damping of the pneumatic actuator bring the dynamic delay of the pressure response and cause the oscillatory motion. In this study, a variable rotary brake comprising Magneto-Rheological Fluid is equipped to the joint of a pneumatic manipulator. Experiments of step response have proved that the transient response of the manipulator could be improved compared with that of the conventional control algorithm by using a phase plane switching control algorithm.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.105-108
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• 2005

We demonstrate an electro-optical device based on the flexoelectric effect of a short-pitched cholesteric liquid crystal. By using a dual-frequency switchable nematic, a small amount of chiral dopant and a small amount of phase-separated polymer localized on the surface, we were able to create a device that operates in amplitude (flexoelectric) and phase(dielectric) modes. At high frequency the dual frequency liquid crystal suppresses the phase mode at higher voltage, which improves the switching speed, and thereby preserving the in-plane-switching mode.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.7
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• pp.523-528
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• 2000

In this short note the characteristics of a nonlinear system of which the state trajectories are oscillating in the phase plane are overviewed. The physical concept of stuck and sliding patch phenomena are also introduced by adding some switching functions and their stability on the sliding patches are analyzed by using the Lyapunov stability theory and Frobenius theorem.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.6
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• pp.633-640
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• 2004

We have studied color tracking of a fringe-field driven homogenously aligned nematic liquid crystal (LC) cell with negative dielectric anisotropy and compared it with other devices such as the twisted nematic(TN) and in-plane switching(IPS) modes. According to studies, the TN device shows bluish color at grey scale and even at a low retardation cell it cannot avoid color tracking. The authentic IPS device having cell retardation value of 0.23 ${\mu}{\textrm}{m}$ also shows bluish white color. However, the FFS device shows excellent color tracking characteristics even at high retardation value of the cell while keeping high transmittance and greenish white.

• Proceedings of the Korean Magnestics Society Conference
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• 2013.05a
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• pp.54-54
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• 2013

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.05a
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• pp.142-145
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• 1999

In this paper, delay performances are evaluated and compared for three dual-plane switch architectures; dual input queue/dual switching plane (DQDP The terms of DQDP, DQDP-PS and DQDP-GQ were not used in [Turner88], [Lee96] and [Son97]. All these tern are designated in this letter for convenience.) switch, DQDP with plane selector (DQDP-PS) switch and DQDP based on output group queueing (DQDP-OGQ) switch. We show that under random traffic these switches give almost identical delay performances to that of the output queueing switch but under bursty traffic only the DQDP-PS and the DQDP-OGQ switches ran do.