365 research outputs found
The Entropy of a Binary Hidden Markov Process
The entropy of a binary symmetric Hidden Markov Process is calculated as an
expansion in the noise parameter epsilon. We map the problem onto a
one-dimensional Ising model in a large field of random signs and calculate the
expansion coefficients up to second order in epsilon. Using a conjecture we
extend the calculation to 11th order and discuss the convergence of the
resulting series
Localizing the Latent Structure Canonical Uncertainty: Entropy Profiles for Hidden Markov Models
This report addresses state inference for hidden Markov models. These models
rely on unobserved states, which often have a meaningful interpretation. This
makes it necessary to develop diagnostic tools for quantification of state
uncertainty. The entropy of the state sequence that explains an observed
sequence for a given hidden Markov chain model can be considered as the
canonical measure of state sequence uncertainty. This canonical measure of
state sequence uncertainty is not reflected by the classic multivariate state
profiles computed by the smoothing algorithm, which summarizes the possible
state sequences. Here, we introduce a new type of profiles which have the
following properties: (i) these profiles of conditional entropies are a
decomposition of the canonical measure of state sequence uncertainty along the
sequence and makes it possible to localize this uncertainty, (ii) these
profiles are univariate and thus remain easily interpretable on tree
structures. We show how to extend the smoothing algorithms for hidden Markov
chain and tree models to compute these entropy profiles efficiently.Comment: Submitted to Journal of Machine Learning Research; No RR-7896 (2012
Phenomenological Implications of a Magnetic 5th Force
A 5th force coupling to baryon number has been proposed to account for
the correlations between the acceleration differences of the
samples studied in the E\"{o}tv\"{o}s experiment, and the corresponding
differences in the baryon-to-mass ratios . To date the
E\"{o}tv\"{o}s results have not been supported by modern experiments. Here we
investigate the phenomenological implications of a possible magnetic analog
of the conventional 5th force electric field,
, arising from the Earth's rotation. We demonstrate that,
in the presence of couplings proportional to , both the
magnitude and direction of a possible 5th force field could be quite different
from what would otherwise be expected and warrants further investigation.Comment: 31 pages, 1 figure, ws-ijmpa.cls, minor changes, final version to
appear in International Journal of Modern Physics
The impact of electron anisotropy on the polarization of the X-ray emission from black hole accretion disks and implications for the black hole X-ray binary 4U 1630-47
The Imaging X-ray Polarimetry Explorer (IXPE) observations of the X-ray
binary 4U 1630-47 in the high soft state revealed linear polarization degrees
(PDs) rising from 6% at 2 keV to 10% at 8 keV. Explaining the results in the
framework of the standard optically thick, geometrically thin accretion disk
scenario requires careful fine-tuning of the relevant model parameters. We
argue here that the emission of polarized Bremsstrahlung by anisotropic
electrons in the accretion disk atmosphere can account for the overall high PDs
and the increase of the PDs with energy. We discuss plasma and accretion
effects that can generate electron anisotropies at a level required by the 4U
1630-47 results. We conclude by emphasizing that X-ray polarimetry affords us
the opportunity to obtain information about the magnetization of the accretion
disk atmosphere.Comment: 8 pages and 6 figures, submitted to the Astrophysical Journal Letter
Developing core sets for persons following amputation based on the International Classification of Functioning, Disability and Health as a way to specify functioning
Amputation is a common late stage sequel of peripheral vascular disease and diabetes or a sequel of accidental trauma, civil unrest and landmines. The functional impairments affect many facets of life including but not limited to: Mobility; activities of daily living; body image and sexuality. Classification, measurement and comparison of the consequences of amputations has been impeded by the limited availability of internationally, multiculturally standardized instruments in the amputee setting. The introduction of the International Classification of Functioning, Disability and Health (ICF) by the World Health Assembly in May 2001 provides a globally accepted framework and classification system to describe, assess and compare function and disability. In order to facilitate the use of the ICF in everyday clinical practice and research, ICF core sets have been developed that focus on specific aspects of function typically associated with a particular disability. The objective of this paper is to outline the development process for the ICF core sets for persons following amputation. The ICF core sets are designed to translate the benefits of the ICF into clinical routine. The ICF core sets will be defined at a Consensus conference which will integrate evidence from preparatory studies, namely: (a) a systematic literature review regarding the outcome measures of clinical trails and observational studies, (b) semi-structured patient interviews, (c) international experts participating in an internet-based survey, and (d) cross-sectional, multi-center studies for clinical applicability. To validate the ICF core sets field-testing will follow. Invitation for participation: The development of ICF Core Sets is an inclusive and open process. Anyone who wishes to actively participate in this process is invited to do so
A New Multi-Layers Method to Analyze Gene Expression
In the paper a new Multi-Layers approach called Multi-Layers Model MLM) for the analysis of stochastic signals and its application to the analysis of gene expression data is presented. It consists in the generation of sub-samples from the input signal by applying a threshold technique based on cut-set optimal conditions. The MLM has been applied on synthetic and real microarray data for the identification of particular regions across DNA called nucleosomes and linkers. Nucleosomes are the fundamental repeating subunits of all eukaryotic chromatin, and their positioning provides useful information regarding the regulation of gene expression in eukaryotic cells. Results have shown a good recognition rate on synthetic data, moreover, the MLM shows a good agreement with a recently published method based on Hidden Markov Model when tested on the Saccharomyces cerevisiae chromosomes microarray data
Spectral Subtraction of Robot Motion Noise for Improved Event Detection in Tactile Acceleration Signals
New robots for teleoperation and autonomous manipulation are increasingly being equipped with high-bandwidth accelerometers for measuring the transient vibrational cues that occur during con- tact with objects. Unfortunately, the robot\u27s own internal mechanisms often generate significant high-frequency accelerations, which we term ego-vibrations. This paper presents an approach to characterizing and removing these signals from acceleration measurements. We adapt the audio processing technique of spectral subtraction over short time windows to remove the noise that is estimated to occur at the robot\u27s present joint velocities. Implementation for the wrist roll and gripper joints on a Willow Garage PR2 robot demonstrates that spectral subtraction significantly increases signal-to-noise ratio, which should improve vibrotactile event detection in both teleoperation and autonomous robotics
Tragedia intitulada: Sara Sampson: en cinco actos
En la port. sello: "Se hallara en la Imprenta de Orga, calle de las Barcas, en Valencia, nº 13"Nombre del autor tomado del "Catálogo de comedias sueltas conservadas en la Biblioteca de la Real Academia Española".Precede al tít. "N. 45"Los datos del pie de imprenta tomados del colofónSign.: A-D4Text a 2 col
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