1,140 research outputs found
Refinement of the random coding bound
An improved pre-factor for the random coding bound is proved. Specifically,
for channels with critical rate not equal to capacity, if a regularity
condition is satisfied (resp. not satisfied), then for any a
pre-factor of (resp. ) is achievable for rates above the
critical rate, where and is the blocklength and rate, respectively. The
extra term is related to the slope of the random coding
exponent. Further, the relation of these bounds with the authors' recent
refinement of the sphere-packing bound, as well as the pre-factor for the
random coding bound below the critical rate, is discussed.Comment: Submitted to IEEE Trans. Inform. Theor
The third-order term in the normal approximation for singular channels
For a singular and symmetric discrete memoryless channel with positive
dispersion, the third-order term in the normal approximation is shown to be
upper bounded by a constant. This finding completes the characterization of the
third-order term for symmetric discrete memoryless channels. The proof method
is extended to asymmetric and singular channels with constant composition
codes, and its connection to existing results, as well as its limitation in the
error exponents regime, are discussed.Comment: Submitted to IEEE Trans. Inform. Theor
Watermarking via zero assigned filter banks
Cataloged from PDF version of article.In order to identify the owner and distributor of digital data, a watermarking scheme in
frequency domain for multimedia files is proposed. The scheme satisfies the
imperceptibility and persistence requirements and it is robust against additive noise.
It consists of a few stages of wavelet decomposition of several subblocks of the original
signal using special zero assigned filter banks. By assigning zeros to filters on the high
frequency portion of the spectrum, filter banks with frequency selective response are
obtained. The information is then inserted in the wavelet-decomposed and compressed
signal. Several robustness tests are performed on male voice, female voice, and music
files, color and gray level images. The algorithm is tested under white Gaussian noise
and against JPEG compression and it is observed to be robust even when exposed to high
levels of corruption.
& 2009 Elsevier B.V. All rights reserve
Minimally invasive double lung transplantation technique (Anteroaxillary approach)
Lung transplantation has been performed through several approaches in the past. Sternothoracotomy is the most widely used approach for double lung transplantation. Although bilateral anterolateral thoracotomy for double lung transplantation has been described in the past, this approach has not widely adopted worldwide. The 'anteroaxillary approach' utilizes a limited incision compared to others, preserves sternal anatomy as well as thoracic arteries, and provides an excellent exposure to hilum. We would like to present our standard approach at University of Pittsburgh through anteroaxillary incision
First quantized electron and photon model of QED and radiative processes
In this study we combine the classical models of the massive and massless
spinning particles, derive the current-current interaction Lagrangian of the
particles from the gauge transformations of the classical spinors, and discuss
radiative processes in electrodynamics by using the solutions of the Dirac
equation and the quantum wave equations of the photon. The longitudinal
polarized photon states give a new idea about the vacuum concept in
electrodynamics.Comment: LaTeX file, 20 pages, 7 figures. to appear in Canadian Journal of
Physic
Automated discrimination of psychotropic drugs in mice via computer vision-based analysis
Cataloged from PDF version of article.We developed an inexpensive computer vision-based method utilizing an algorithm which differentiates
drug-induced behavioral alterations. The mice were observed in an open-field arena and their activity
was recorded for 100 min. For each animal the first 50 min of observation were regarded as the drug-free
period. Each animal was exposed to only one drug and they were injected (i.p.) with either amphetamine
or cocaine as the stimulant drugs or morphine or diazepam as the inhibitory agents. The software divided
the arena into virtual grids and calculated the number of visits (sojourn counts) to the grids and instantaneous
speeds within these grids by analyzing video data. These spatial distributions of sojourn counts and
instantaneous speeds were used to construct feature vectors which were fed to the classifier algorithms
for the final step of matching the animals and the drugs. The software decided which of the animals were
drug-treated at a rate of 96%. The algorithm achieved 92% accuracy in sorting the data according to the
increased or decreased activity and then determined which drug was delivered. The method differentiated
the type of psychostimulant or inhibitory drugs with a success ratio of 70% and 80%, respectively.
This method provides a new way to automatically evaluate and classify drug-induced behaviors in mice.
Crown Copyright © 2009 Published by Elsevier B.V. All rights reserved
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