• 대한치과보철학회:학술대회논문집
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• 2005.11a
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• pp.86-86
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• 2005

• The Magazine of the IEIE
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• v.40 no.9
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• pp.26-33
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• 2013

• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.720-725
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• 2013

This paper has presented that fringing-electric fields enhanced by a finger-type electrode can improve the tunability of the tunable capacitor. Its top electrodes with different area and line width are designed in types of the finger for a long conducting perimeter. The tunable varactors were fabricated on a quartz substrate employing a multi-layer dielectric of a para/ferro/para-electric thin film. Compared to the conventional capacitor, finger-type capacitors are analyzed in terms of effective capacitance and tunablility. Their effective capacitance and tunability of the varactors with the long perimeter increase 24~40 % and 7~12 %, respectively, due to enhanced fringing electric fields from 1 to 2.5 GHz.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.84.2-84.2
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• 2005

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.311-312
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• 2012

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.9
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• pp.1202-1202
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• 2001

• Proceedings of the Optical Society of Korea Conference
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• 2006.02a
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• pp.167-168
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• 2006

• Journal of Korea Society of Industrial Information Systems
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• v.9 no.3
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• pp.1-10
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• 2004

Video-On-Demand servers use compression techniques to reduce the storage and bandwidth requirements. The compression techniques make the bit rates of compressed video data significantly variable from frame to frame. Consequently, Video-On-Demand servers with a constant bit rate retrieval can not maximize the utilization of resources. It is possible that when variable bit rate video data is stored, accurate description of the bit rate changes could be computed a priori. In this paper, I propose a buffer management scheme called MAX for Video-On-Demand server using variable bit rate continuous media. By caching and prefetching the data, MAX buffer management scheme reduces the variation of the compressed data and increases the number of clients simultaneously served and maximizes the utilization of system resources. Results of trace-driven simulations show the effectiveness of the scheme.

• Korean Journal of Optics and Photonics
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• v.20 no.4
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• pp.217-222
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• 2009

In this paper, a low-cost hybrid-integrated tunable laser is realized using a polymer-ring resonator-based add/drop filter reflector and a reflective semiconductor optical amplifier. The add/drop filter reflector, composed of a double-ring resonator with different radii, can have characteristics of selective wavelength reflection and wide wavelength tuning with an aid of vernier effect derived from the radii difference. By hybrid-integrating the reflective semiconductor optical amplifier with the add/drop filter reflector, a tunable laser can be realized through an active alignment method. The hybrid laser exhibited a single mode lasing with side mode suppression ratio of 26 dB and full width half maximum of 0.03 nm. In addition, applying a low current as small as 25 mA onto electrodes over add/drop filter reflector, a wavelength tuning range of 17 nm could be obtained.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.3
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• pp.282-288
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• 2014

Recently there have been much interest in the GPS antenna performance improvement. In this paper, we propose very small patch antenna for GPS band. The proposed antenna resonance frequency was adjusted using the ground plane and variable capacitor connected the frame. The fabricated antenna was used a FR4 substrate by considering the difficulty and economical efficiency. Antenna measurement results was obtained good characteristics of VSWR 1.2, the passive antenna gain -0.60 dBi, the active antenna gain of 29 dB in center frequency of 1575.42 MHz GPS band.