Search results for "Process"

Energy dissipative characteristic schemes for the diffusive Oldroyd-B viscoelastic fluid

2015

Itô calculus extended to systems driven by -stable Lévy white noises (a novel clip on the tails of Lévy motion)

2007

Abstract The paper deals with probabilistic characterization of the response of non-linear systems under α -stable Levy white noise input. It is shown that, by properly selecting a clip in the probability density function of the input, the moments of the increments of Levy motion process remain all of the same order ( d t ) , like the increments of the Compound Poisson process. It follows that the Ito calculus extended to Poissonian input, may also be used for α -stable Levy white noise input processes. It is also shown that, when the clip on the tails of the probability of the increments of the Levy motion approaches to infinity, the Einstein–Smoluchowsky equation is restored. Once these c…

A regularized Newton method for locating thin tubular conductivity inhomogeneities

2011

We consider the inverse problem of determining the position and shape of a thin tubular object, such as for instance a wire, a thin channel or a curve-like crack, embedded in some three-dimensional homogeneous body from a single measurement of electrostatic currents and potentials on the boundary of the body. Using an asymptotic model describing perturbations of electrostatic potentials caused by such thin objects, we reformulate the inverse problem as a nonlinear operator equation. We establish Frechet differentiability of the corresponding operator, compute its Frechet derivative and set up a regularized Newton scheme to solve the inverse problem numerically. We discuss our implementation…

Jacobian of solutions to the conductivity equation in limited view

2022

Abstract The aim of hybrid inverse problems such as Acousto-Electric Tomography or Current Density Imaging is the reconstruction of the electrical conductivity in a domain that can only be accessed from its exterior. In the inversion procedure, the solutions to the conductivity equation play a central role. In particular, it is important that the Jacobian of the solutions is non-vanishing. In the present paper we address a two-dimensional limited view setting, where only a part of the boundary of the domain can be controlled by a non-zero Dirichlet condition, while on the remaining boundary there is a zero Dirichlet condition. For this setting, we propose sufficient conditions on the bounda…

Computer-aided-diagnosis for ocular abnormalities from a single color fundus photography with deep learning

2023

Any damage to the retina can lead to severe consequences like blindness. This visual impairment is preventable by early detection of ocular abnormalities. Computer-aided diagnosis (CAD) for ocular abnormalities is built by analyzing retinal imaging modalities, for instance, Color Fundus Photography (CFP). The main objectives of this thesis are to build two CAD models, one to detect the microaneurysms (MAs), the first visible symptom of diabetic retinopathy, and the other for multi-label detection of 28 ocular abnormalities consisting of frequent and rare abnormalities from a single CFP by using deep learning-based approaches. Two methods were proposed for MAs detection: ensemble-based and c…

A multicenter study on the appropriateness of hospitalization in obstetric wards: application of Obstetric Appropriateness Evaluation Protocol (Obste…

2015

The cross-sectional study has been based on the implementation of the Obstetric Appropriateness Evaluation Protocol (OAEP) in seven hospitals to determine inappropriate hospital admissions and days of stay. The outcomes were: inappropriateness of admission and "percentage of inappropriateness" for one hospitalization. A total number of 2196 clinical records were reviewed. The mean percentage of inappropriateness for hospitalization was 22%. The percentage of inappropriateness for the first 10 d of hospitalization peaked in correspondence of the fourth (42%). The logistic regression model on inappropriated admission reported that emergency admission was a protective factor (OR = 0.4) and to …

Activity-Centered Design: An Appropriation Issue

2011

When designing workplace computer systems one must take human activity into account. It has become standard practice to approach this issue through user-centered design. The aim of this paper is to stimulate thought on activity-centered design and to propose the concept of appropriation as a fundamental principle of this design approach. This orientation aims to take into consideration the constituent function of tools during conception. We will take the design of computer systems dedicated to customer relations as an example.

Melancolía de mujeres Solas.

2019

En este trabajo vamos a relacionar la película de Benito Zambrano Solas (1999) con el género o familia de films del melodrama de la mujer desconocida que propone Cavell (2009). Para ello, después de introducir el “método” asociativo cavelliano, vamos a presentar los rasgos más característicos de dicho género y la imagen de la mujer que en ellos se dibuja: el autoconocimiento de la protagonista, su relación con el mundo masculino, su emancipación del mismo a través de la conquista de la voz. El resto del trabajo consiste en una propuesta de lectura de la película de Zambrano, dentro de un marco cavelliano, pero subrayando el papel de la melancolía como mito cultural (Bartra 2001), la relació…

Influence of Active Device Nonlinearities on the Determination of Adler's Injection.Locking Q-Factor

2011

The problem of the correct evaluation of Q-factor appearing in Adler's equation for injection-locking is addressed. Investigation has shown that recent results presented in the literature, while extending applicability of the original method, do not completely account for nonlinear effects occurring when two-port active devices are involved. To overcome such limitation, use can be made of a newly developed theory in the dynamical complex envelope domain, capable of providing first-approximation exact dynamical models of driven quasi-sinusoidal oscillators. Some preliminary results are presented here concerning a class of injection-locked oscillators with single-loop feedback type configurat…

Finite element approximation of parabolic hemivariational inequalities

1998

In this paper we introduce a finite element approximation for a parabolic hemivariational initial boundary value problem. We prove that the approximate problem is solvable and its solutions converge on subsequences to the solutions of the continuous problem