Search results for "PROB"
showing 10 items of 8859 documents
Influence of organic material and sample parameters on the surface potential in Kelvin probe measurements
2019
Financial support provided by ERDF 1.1.1.1 activity project Nr. 1.1.1.1/16/A/046 “Application assessment of novel organic materials by prototyping of photonic devices” as well as Scientific Research Project for Students and Young Researchers Nr. SJZ2016/20 realized at the Institute of Solid State Physics, University of Latvia is greatly acknowledged.
Inherent information in the prices of options
2018
Esta tesis tiene como objetivo analizar el contenido informacional de los precios observados de las opciones. En este caso particular, teniendo diferentes opciones sobre el mismo subyacente y con la misma fecha de vencimiento, podemos obtener información sobre la función de densidad neutral al riesgo (RND). Éstas son las densidades con las que los agentes valoran los activos derivados, y en definitiva cómo ponen precio a unidades de consumo en diferentes estados de la naturaleza futuros. Esta información implícita en el precio de las opciones es considerada información forward-looking (con miras al futuro). Esta tesis consta de tres capítulos enfocados a analizar diferentes aspectos de los …
Inverse problems and invisibility cloaking for FEM models and resistor networks
2013
In this paper we consider inverse problems for resistor networks and for models obtained via the finite element method (FEM) for the conductivity equation. These correspond to discrete versions of the inverse conductivity problem of Calderón. We characterize FEM models corresponding to a given triangulation of the domain that are equivalent to certain resistor networks, and apply the results to study nonuniqueness of the discrete inverse problem. It turns out that the degree of nonuniqueness for the discrete problem is larger than the one for the partial differential equation. We also study invisibility cloaking for FEM models, and show how an arbitrary body can be surrounded with a layer …
On FE-grid relocation in solving unilateral boundary value problems by FEM
1992
We consider FE-grid optimization in elliptic unilateral boundary value problems. The criterion used in grid optimization is the total potential energy of the system. It is shown that minimization of this cost functional means a decrease of the discretization error or a better approximation of the unilateral boundary conditions, Design sensitivity analysis is given with respect to the movement of nodal points. Numerical results for the Dirichlet-Signorini problem for the Laplace equation and the plane elasticity problem with unilateral boundary conditions are given. In plane elasticity we consider problems with and without friction. peerReviewed
A fast Fourier transform based direct solver for the Helmholtz problem
2018
This article is devoted to the efficient numerical solution of the Helmholtz equation in a two‐ or three‐dimensional (2D or 3D) rectangular domain with an absorbing boundary condition (ABC). The Helmholtz problem is discretized by standard bilinear and trilinear finite elements on an orthogonal mesh yielding a separable system of linear equations. The main key to high performance is to employ the fast Fourier transform (FFT) within a fast direct solver to solve the large separable systems. The computational complexity of the proposed FFT‐based direct solver is O(N log N) operations. Numerical results for both 2D and 3D problems are presented confirming the efficiency of the method discussed…
On an idea of Bakhtin and Czerwik for solving a first-order periodic problem
2017
We study the existence of solutions to a first-order periodic problem involving ordinary differential equations, by using the quasimetric structure suggested by Bakhtin and Czerwik. The presented approach involves technical conditions and fixed point iterative schemes to yield new theoretical results guaranteeing the existence of at least one solution.
El cuerpo materno en la red: entre el orden de lo ?deseable? y el de lo real
2019
El estilo de vida fitness se realiza en, y a través de, un entramado subjetivo y de poder en el que circulan y se ensamblan dispositivos empresariales, terapéuticos, sanitarios y de espectacularización de los cuerpos, tendientes a inscribir la vida de la población en las tramas conflictivas de un capitalismo heterosexista, neoliberal e informacional. En dicho marco, la temporalidad, metamorfosis y plasticidad del cuerpo materno irrumpe como problema y objeto de intervención de tecnologías diversas orientadas a ajustar su tamaño, forma y devenir a los parámetros de la vida activa y saludable. En escenarios digitales, dicha tensión se materializa, por un lado, a través de dispositivos visuale…
The FLO Diffusive 1D-2D Model for Simulation of River Flooding
2016
An integrated 1D-2D model for the solution of the diffusive approximation of the shallow water equations, named FLO, is proposed in the present paper. Governing equations are solved using the MArching in Space and Time (MAST) approach. The 2D floodplain domain is discretized using a triangular mesh, and standard river sections are used for modeling 1D flow inside the section width occurring with low or standard discharges. 1D elements, inside the 1D domain, are quadrilaterals bounded by the trace of two consecutive sections and by the sides connecting their extreme points. The water level is assumed to vary linearly inside each quadrilateral along the flow direction, but to remain constant …
Central limit theorem for bifurcating Markov chains under L 2 -ergodic conditions
2021
Bifurcating Markov chains (BMC) are Markov chains indexed by a full binary tree representing the evolution of a trait along a population where each individual has two children. We provide a central limit theorem for additive functionals of BMC under L 2-ergodic conditions with three different regimes. This completes the pointwise approach developed in a previous work. As application, we study the elementary case of symmetric bifurcating autoregressive process, which justify the non-trivial hypothesis considered on the kernel transition of the BMC. We illustrate in this example the phase transition observed in the fluctuations.