Search results for "Algorithm"
showing 10 items of 4887 documents
Shift-Invariant Canonical Polyadic Decomposition of Complex-Valued Multi-Subject fMRI Data with a Phase Sparsity Constraint
2020
Canonical polyadic decomposition (CPD) of multi-subject complex-valued fMRI data can be used to provide spatially and temporally shared components among groups with both magnitude and phase information. However, the CPD model is not well formulated due to the large subject variability in the spatial and temporal modalities, as well as the high noise level in complex-valued fMRI data. Considering that the shift-invariant CPD can model temporal variability across subjects, we propose to further impose a phase sparsity constraint on the shared spatial maps to denoise the complex-valued components and to model the inter-subject spatial variability as well. More precisely, subject-specific time …
Efficient checking of coherence and propagation of imprecise probability assessments
2000
We consider the computational difficulties in the checking of coherence and propagation of imprecise probability assessments. We examine the linear structure of the random gain in betting criterion and we propose a general methodology which exploits suitable subsets of the set of values of the random gain. In this way the checking of coherence and propagation amount to examining linear systems with a reduced number of unknowns. We also illustrate an example.
Probabilistic Logic under Coherence: Complexity and Algorithms
2005
In previous work [V. Biazzo, A. Gilio, T. Lukasiewicz and G. Sanfilippo, Probabilistic logic under coherence, model-theoretic probabilistic logic, and default reasoning in System P, Journal of Applied Non-Classical Logics 12(2) (2002) 189---213.], we have explored the relationship between probabilistic reasoning under coherence and model-theoretic probabilistic reasoning. In particular, we have shown that the notions of g-coherence and of g-coherent entailment in probabilistic reasoning under coherence can be expressed by combining notions in model-theoretic probabilistic reasoning with concepts from default reasoning. In this paper, we continue this line of research. Based on the above sem…
Strictly convergent algorithm for an elliptic equation with nonlocal and nonlinear boundary conditions
2012
The paper describes a formally strictly convergent algorithm for solving a class of elliptic problems with nonlinear and nonlocal boundary conditions, which arise in modeling of the steady-state conductive-radiative heat transfer processes. The proposed algorithm has two levels of iterations, where inner iterations by means of the damped Newton method solve an appropriate elliptic problem with nonlinear, but local boundary conditions, and outer iterations deal with nonlocal terms in boundary conditions.
GLI3 is rarely implicated in OFD syndromes with midline abnormalities
2011
A range of phenotypes including Greig cephalopolysyndactyly and Pallister-Hall syndromes (GCPS, PHS) are caused by pathogenic mutation of the GLI3 gene. To characterize the clinical variability of GLI3 mutations, we present a subset of a cohort of 174 probands referred for GLI3 analysis. Eighty-one probands with typical GCPS or PHS were previously reported, and we report the remaining ninety-three probands here. This includes nineteen probands (twelve mutations) who fulfilled clinical criteria for GCPS or PHS, forty-eight probands (sixteen mutations) with features of GCPS or PHS but who did not meet the clinical criteria (sub-GCPS and sub-PHS), twenty-one probands (six mutations) with featu…
Methionine in a protein hydrophobic core drives tight interactions required for assembly of spider silk
2019
Web spiders connect silk proteins, so-called spidroins, into fibers of extraordinary toughness. The spidroin N-terminal domain (NTD) plays a pivotal role in this process: it polymerizes spidroins through a complex mechanism of dimerization. Here we analyze sequences of spidroin NTDs and find an unusually high content of the amino acid methionine. We simultaneously mutate all methionines present in the hydrophobic core of a spidroin NTD from a nursery web spider’s dragline silk to leucine. The mutated NTD is strongly stabilized and folds at the theoretical speed limit. The structure of the mutant is preserved, yet its ability to dimerize is substantially impaired. We find that side chains of…
Evaluation of the risk factors of asymptomatic vertebral fractures in postmenopausal women with osteopenia at the femoral neck
2016
To identify risk factors of asymptomatic vertebral fracture (aVF) in postmenopausal women with osteopenia at the femoral neck and to evaluate the association between the number of aVFs and the risk of major and hip osteoporotic fracture calculated with the FRAX(®) algorithm.Epidemiological case-series study with data collected transversally.728 postmenopausal women with osteopenia were included: 284 (39.0%) had aVF, of whom 200 (70.4%) had prior fragility fractures (FF). The likelihood of having an osteoporotic fracture in the next 10 years increased significantly with the number of aVF. The percentage of women with height loss, which was assessed as the difference between the greatest heig…
Le Graphe Génératif Gaussien
2009
International audience; Un nuage de points est plus qu'un ensemble de points isolés. La distribution des points peut être gouvernée par une structure topologique cachée, et du point de vue de la fouille de données, modéliser et extraire cette structure est au moins aussi important que d'estimer la seule densité de probabilité du nuage. Dans cet article, nous proposons un modèle génératif basé sur le graphe de Delaunay d'un ensemble de prototypes représentant le nuage de points, et supposant un bruit gaussien. Nous dérivons un algorithme pour la maximisation de la vraisemblance des paramètres, et nous utilisons le critère BIC pour sélectionner la complexité du modèle. Ce travail a pour objec…
An effective approach for the maintenance scheduling in large systems with required reliability level: A case study
2015
This paper deals with the problem of the maintenance scheduling in a multi-component system for which a required reliability level has to be warranted until the next planned stop for maintenance. Particularly, the tackled problem concerns both the determination of the elements set on which to perform preventive maintenance and the optimal number of maintenance crews in order to warranty the required reliability level at the minimum maintenance cost. The problem is formulated as a mathematical programming model that becomes very hard to solve for large practical systems. For such reason, a new effective approach based on a constrained genetic algorithm is herein proposed and tested with refe…
Towards an efficient meshfree solver
2016
In this paper we focus on the enhancement in accuracy approximating a function and its derivatives via smoothed particle hydrodynamics. We discuss about improvements in the solution by reformulating the original method by means of the Taylor series expansion and by projecting with the kernel function and its derivatives. The accuracy of a function and its derivatives, up to a fixed order, can be simultaneously improved by assuming them as unknowns of a linear system. The improved formulation has been assessed with gridded and scattered data points distribution and the convergence has been analyzed referring to a case study in a 2D domain.