8,722 research outputs found
Multicasting Homogeneous and Heterogeneous Quantum States in Quantum Networks
In this paper, we target the practical implementation issues of quantum
multicast networks. First, we design a recursive lossless compression that
allows us to control the trade-off between the circuit complexity and the
dimension of the compressed quantum state. We give a formula that describes the
trade-off, and further analyze how the formula is affected by the controlling
parameter of the recursive procedure. Our recursive lossless compression can be
applied in a quantum multicast network where the source outputs homogeneous
quantum states (many copies of a quantum state) to a set of destinations
through a bottleneck. Such a recursive lossless compression is extremely useful
in the current situation where the technology of producing large-scale quantum
circuits is limited. Second, we develop two lossless compression schemes that
work for heterogeneous quantum states (many copies of a set of quantum states)
when the set of quantum states satisfies a certain structure. The heterogeneous
compression schemes provide extra compressing power over the homogeneous
compression scheme. Finally, we realize our heterogeneous compression schemes
in several quantum multicast networks, including the single-source
multi-terminal model, the multi-source multi-terminal model, and the ring
networks. We then analyze the bandwidth requirements for these network models.Comment: 24 pages, 9 figure
A Computable Measure of Algorithmic Probability by Finite Approximations with an Application to Integer Sequences
Given the widespread use of lossless compression algorithms to approximate
algorithmic (Kolmogorov-Chaitin) complexity, and that lossless compression
algorithms fall short at characterizing patterns other than statistical ones
not different to entropy estimations, here we explore an alternative and
complementary approach. We study formal properties of a Levin-inspired measure
calculated from the output distribution of small Turing machines. We
introduce and justify finite approximations that have been used in some
applications as an alternative to lossless compression algorithms for
approximating algorithmic (Kolmogorov-Chaitin) complexity. We provide proofs of
the relevant properties of both and and compare them to Levin's
Universal Distribution. We provide error estimations of with respect to
. Finally, we present an application to integer sequences from the Online
Encyclopedia of Integer Sequences which suggests that our AP-based measures may
characterize non-statistical patterns, and we report interesting correlations
with textual, function and program description lengths of the said sequences.Comment: As accepted by the journal Complexity (Wiley/Hindawi
Data Streams from the Low Frequency Instrument On-Board the Planck Satellite: Statistical Analysis and Compression Efficiency
The expected data rate produced by the Low Frequency Instrument (LFI) planned
to fly on the ESA Planck mission in 2007, is over a factor 8 larger than the
bandwidth allowed by the spacecraft transmission system to download the LFI
data. We discuss the application of lossless compression to Planck/LFI data
streams in order to reduce the overall data flow. We perform both theoretical
analysis and experimental tests using realistically simulated data streams in
order to fix the statistical properties of the signal and the maximal
compression rate allowed by several lossless compression algorithms. We studied
the influence of signal composition and of acquisition parameters on the
compression rate Cr and develop a semiempirical formalism to account for it.
The best performing compressor tested up to now is the arithmetic compression
of order 1, designed for optimizing the compression of white noise like
signals, which allows an overall compression rate = 2.65 +/- 0.02. We find
that such result is not improved by other lossless compressors, being the
signal almost white noise dominated. Lossless compression algorithms alone will
not solve the bandwidth problem but needs to be combined with other techniques.Comment: May 3, 2000 release, 61 pages, 6 figures coded as eps, 9 tables (4
included as eps), LaTeX 2.09 + assms4.sty, style file included, submitted for
the pubblication on PASP May 3, 200
Importance of Watermark Lossless Compression in Digital Medical Image Watermarking
Large size data requires more storage space, communication time, communication bandwidth and degrades host image
quality when it is embedded into it as watermark. Lossless compression reduces data size better than lossless one but with permanent loss of important part of data. Data lossless compression reduces data size contrast to lossy one without any data loss. Medical image data is very sensitive and needs lossless compression otherwise it will result in erroneous input for the health recovery process. This paper focuses on Ultrasound medical image region of interest(ROI) lossless compression as watermark using different techniques; PNG, GIF, JPG, JPEG2000 and Lempel Ziv Welsh (LZW). LZW technique was found 86% better than other tabulated techniques. Compression ratio and more bytes reduction were the parameters considered for the selection of better compression technique. In this work LZW has been used successfully for watermark lossless compression to watermark medical images in teleradiology to ensure less payload encapsulation into images to preserve
their perceptual and diagnostic qualities unchanged. On the other side in teleradiology the extracted lossless decompressed watermarks ensure the images authentication and their lossless recoveries in case of any tamper occurrences
On Lossless Compression of 1-bit Audio Signals
In this paper we consider the problem of lossless compression of 1-bit audio signals. We study the properties of some existing proposed solutions. We also discuss possible improvements. Other methods have been considered, and the results are reported
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