Search results for "VARIATION"
showing 10 items of 2124 documents
Non-cooperative power allocation game with imperfect sensing information for cognitive radio
2012
In this paper, we consider a sensing-based spectrum sharing scenario and present an efficient decentralized algorithm to maximize the total throughput of the cognitive radio users by optimizing jointly both the detection operation and the power allocation, taking into account the influence of the sensing accuracy. This optimization problem can be formulated as a distributed non-cooperative power allocation game, which can be solved by using an alternating direction optimization method. The transmit power budget of the cognitive radio users and the constraint related to the rate-loss of the primary user due to the interference are considered in the scheme. Finally, we use variational inequal…
tbg - a new file format for genomic data
2021
AbstractMotivationThe question of determining whether a Single-Nucleotide Polymorphism (SNP) or a variant in general leads to a change in the amino acid sequence of a protein coding gene is often a laborious and time-consuming challenge. Here, we introduce the tbg file format for storing genomic data and tbg-tools, a user-friendly toolbox for the faster analysis of SNPs. The file format stores information for each nucleotide in each gene, allowing to predict which change in the amino acid sequence will be caused by a variant in the nucleotide sequence. Our new tool therefore has the potential to make biological sense of the unprecedented amount of genome-wide genetic variation that research…
Total Variation Regularization in Digital Breast Tomosynthesis
2013
We developed an iterative algebraic algorithm for the reconstruction of 3D volumes from limited-angle breast projection images. Algebraic reconstruction is accelerated using the graphics processing unit. We varied a total variation (TV)-norm parameter in order to verify the influence of TV regularization on the representation of small structures in the reconstructions. The Barzilai-Borwein algorithm is used to solve the inverse reconstruction problem. The quality of our reconstructions was evaluated with the Quart Mam/Digi Phantom, which features so-called Landolt ring structures to verify perceptibility limits. The evaluation of the reconstructions was done with an automatic LR detection a…
''Investigating reduction of dimensionality during single-joint elbow movements: a case study on muscle synergies''
2013
Chiovetto, Enrico | Berret, Bastien | Delis, Ioannis | Panzeri, Stefano | Pozzo, Thierry; International audience; ''A long standing hypothesis in the neuroscience community is that the central nervous system (CNS) generates the muscle activities to accomplish movements by combining a relatively small number of stereotyped patterns of muscle activations, often referred to as" muscle synergies." Different definitions of synergies have been given in the literature. The most well-known are those of synchronous, time-varying and temporal muscle synergies. Each one of them is based on a different mathematical model used to factor some EMG array recordings collected during the execution of variety…
Design of composite measure schemes for comparative severity assessment in animal-based neuroscience research: A case study focussed on rat epilepsy …
2020
PLOS ONE 15(5), e0230141 (2020). doi:10.1371/journal.pone.0230141
Improving estimation of distribution genetic programming with novelty initialization
2021
Estimation of distribution genetic programming (EDA-GP) replaces the standard variation operations of genetic programming (GP) by learning and sampling from a probabilistic model. Unfortunately, many EDA-GP approaches suffer from a rapidly decreasing population diversity which often leads to premature convergence. However, novelty search, an approach that searches for novel solutions to cover sparse areas of the search space, can be used for generating diverse initial populations. In this work, we propose novelty initialization and test this new method on a generalization of the royal tree problem and compare its performance to ramped half-and-half (RHH) using a recent EDA-GP approach. We f…
Concordance Analysis
2011
Background In this article, we describe qualitative and quantitative methods for assessing the degree of agreement (concordance) between two measuring or rating techniques. An assessment of concordance is particularly important when a new measuring technique is introduced.
Identificación de Urgencias por Asma y Enfermedad Pulmonar Obstructiva Crónica en el Servicio de Urgencias de un Hospital. Estudio de Concordancia
1999
ResumenObjetivoAnalizar la concordancia de los resultados obtenidos en la identificación de los casos de asma y enfermedad pulmonar obstructiva crónica (EPOC) diagnosticados en las historias clínicas de urgencias del Hospital Clínico Universitario de Valencia.MétodosEn el contexto de un estudio más amplio sobre la relación entre urgencias por asma y EPOC y determinados factores de riesgo ambientales, se revisaron todas las historias clínicas de urgencias médicas de mayores de 14 años del Hospital Clínico Universitario de Valencia correspondientes a los años 1993 y 1994. Los observadores fueron dos diplomados en enfermería, previamente entrenados en el procedimiento de identificación de caso…
Exact and Variational Treatment of Ferroelectric Thin Films with Different Materials of Electrodes
2005
We trace the influence of metallic electrodes on the properties of thin ferroelectric films. This has been done in the framework of the phenomenological Landau theory. We present both exact analytical solution of the problem in terms of Weierstrass elliptic functions and the variational solution. We calculate polarization, dielectric susceptibility, pyroelectric coefficient and depolarization field. We have shown that the ferroelectric phase of the film can be destroyed by the choice of material of electrodes with screening length exceeding some critical value. This demonstrates that we can control the physical properties of thin ferroelectric films by the proper choice of the electrode mat…
Quantum critical point in a periodic Anderson model
2000
We investigate the symmetric Periodic Anderson Model (PAM) on a three-dimensional cubic lattice with nearest-neighbor hopping and hybridization matrix elements. Using Gutzwiller's variational method and the Hubbard-III approximation (which corresponds to the exact solution of an appropriate Falicov-Kimball model in infinite dimensions) we demonstrate the existence of a quantum critical point at zero temperature. Below a critical value $V_c$ of the hybridization (or above a critical interaction $U_c$) the system is an {\em insulator} in Gutzwiller's and a {\em semi-metal} in Hubbard's approach, whereas above $V_c$ (below $U_c$) it behaves like a metal in both approximations. These prediction…