7,850 research outputs found
Localized image watermarking based on feature points of scale-space representation
No full textThis paper proposes a novel method for content-based watermarking based on feature points of an image. At each feature point, the watermark is embedded after scale normalization according to the local characteristic scale. Characteristic scale is the maximum scale of the scale-space representation of an image at the feature point. By binding watermarking with the local characteristics of an image, resilience against affine transformations can be obtained easily. Experimental results show that the proposed method is robust against various image processing steps including affine transformations, cropping, filtering and JPEG compression. (C) 2004 Pattern Recognition Society. Published by Elsevier Ltd. All rights reserved
Hybrid WDM/SCMA-PON using wavelength-locked Fabry-Perot laser diodes
No full textWe propose a large-capacity hybrid passive optical network (PON) with a wavelength-sharing technique achieved by applying subcarrier multiple access on each single channel of a wavelength-division-multiplexed (WDM) PON. We also use forward-error correction to reduce the effect of optical beat interference noise. We demonstrate three-subchannel sharing in a 100-GHz-spaced WDM-PON to accommodate three times more subscribers simultaneously at a fully dedicated connection rate of 125 Mb/s.This work
was supported in part by the National Research Laboratory (NRL) Program of
the Ministry of Science and Technology (MOST)
Speech Enhancement Based on the Generalized Dual Excitation Model with Adaptive Analysis Window
No full textHybrid functional studies of stability and diffusion of hydrogen in Mg-doped GaN
No full textNitride semiconductors are known to suffer from low p-type doping efficiency due to the high activation energy of Mg acceptors and the compensation of hole carriers. To enhance hole carrier concentration, the hydrogen co-doping method is widely used, in which hydrogen is intentionally doped with Mg dopants and removed by subsequent thermal annealing. In this work, we perform first-principles density functional calculations to study the stability and diffusion of hydrogen in Mg-doped GaN. For the exchange-correlation potential, we employ both the generalized gradient approximation (GGA) proposed by Perdew, Burke, and Ernzerhof and the hybrid density functional of Heyd, Scuseria, and Ernzerhof. We examine the diffusion pathways and dissociation barriers of H from the Mg-H complex using the nudged elastic band and dimer methods. We compare the results of the GGA and hybrid density functional calculations for the stability of various H interstitial configurations and the migration barriers for H diffusion. Finally, using the calculated migration barriers as inputs, we perform kinetic Monte Carlo simulations for the dissociation of the Mg-H complex and find that the Mg acceptors are activated by thermal annealing up to 700-800 ^oC, in good agreement with experiments
Transposon mutagenesis and cloning of the genes encoding the enzymes of fengycin biosynthesis in Bacillus subtilis.
No full textVideo-assisted thoracoscopic excision of intradiaphragmatic bronchogenic cysts: two cases.
No full textVideo-assisted thoracoscopic surgery for the diagnosis of patients with hilar and mediastinal lymphadenopathy.
No full textAnalysis of the Effect of Cation in Electrochemically Polymerized Ppy Film by Using Q.C.A
No full textBroad-band light source using mutually injected Fabry-Perot laser diodes for WDM-PON
No full textWe propose and demonstrate a new broad-band light source (BLS) for a wavelength division multiplexing-passive optical network (WDM-PON) based on the wavelength locked Fabry-Perot laser diodes (F-P LDs). By mutual injection between two antireflection-coated F-P LDs, we realized a broad-band light with a low relative intensity noise. By using the proposed BLS for wavelength locking of the F-P LD, we achieve color-free operation of the optical network termination with Manchester coded data. We also demonstrate a WDM-PON based on the proposed BLS.Thisworkwas
supported by the Korea Ministry of Science and Technology under the National
Research Laboratory
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