Cauchy singular integral equation method for transient antiplane dynamic problems

In this paper, by use of the boundary integral equation method and the techniques of Green basic solution and singularity analysis, the dynamic problem of antiplane is investigated. The problem is reduced to solving a Cauchy singular integral equation in Laplace transform space. This equation is strictly proved to be equivalent to the dual integral equations obtained by Sih [Mechanics of Fracture, Vol. 4. Noordhoff, Leyden (1977)]. On this basis, the dynamic influence between two parallel cracks is also investigated. By use of the high precision numerical method for the singular integral equation and Laplace numerical inversion, the dynamic stress intensity factors of several typical problems are calculated in this paper. The related numerical results are compared to be consistent with those of Sih. It shows that the method of this paper is successful and can be used to solve more complicated problems. Copyright (C) 1996 Elsevier Science Ltd

A new type of boundary integral-equation for plane problems of elasticity including rotational forces

Based on the idea proposed by Hu [Scientia Sinica Series A XXX, 385-390 (1987)], a new type of boundary integral equation for plane problems of elasticity including rotational forces is derived and its boundary element formulation is presented. Numerical results for a rotating hollow disk are given to demonstrate the accuracy of the new type of boundary integral equation.

Implantar un Sistema de Gestion Integral en Software libre

El proyecto de fin de carrera “Implantar un Sistema de Gestión Integral en Software libre” se ha desarrollado en la empresa Avanzosc con sede en Azkoitia. Una peculiaridad del proyecto es que a su vez se ha utilizado como cliente otra empresa, q2K, Soluciones Informáticas en Gestión Estratégica. El objetivo del proyecto es implantar en q2K un sistema de planificación de recursos empresariales (ERP, Enterprise Resource Planning), esto le permite reunir en una única aplicación todos los procesos de negocio de la empresa. La implantación de un ERP requiere de una importante inversión ya que el coste de la licencia de un sistema ERP propietario es elevado. Una interesante alternativa para evitar este desembolso es optar por un de ERP de software libre con todas las ventajas de configuración y personalización. En nuestro caso se ha adoptado OpenERP que es un software integral, modular y adaptable, adecuado para pequeñas y medianas empresas. El desarrollo del proyecto ha estado supervisado por el equipo de trabajo de Avanzosc, empresa líder en España en implantación de OpenErp, siguiendo la metodología de trabajo propia de esta empresa.

Gestión integral de la ampliación de una infraestructura de sistemas y servicios

Este proyecto se sitúa en el ámbito de las empresas que ofertan servicios informáticos a terceros. Estas empresas se dedican a cubrir las necesidades de gestión de la infraestructura de sistemas y servicios de los clientes. En concreto, los proyectos de ampliación de esas infraestructuras suelen ser bastante problemáticos. Este proyecto desarrolla un conjunto de procedimientos que permiten gestionar la ampliación de una infraestructura de sistemas y servicios de acuerdo a una librería de buenas prácticas denominada ITIL.

Numerical-Value Perturbation Method with Application of Solving Convective-Diffusion Integral Equation

The convective--diffusion equation is of primary importance in such fields as fluid dynamics and heat transfer hi the numerical methods solving the convective-diffusion equation, the finite volume method can use conveniently diversified grids (structured and unstructured grids) and is suitable for very complex geometry The disadvantage of FV methods compared to the finite difference method is that FV-methods of order higher than second are more difficult to develop in three-dimensional cases. The second-order central scheme (2cs) offers a good compromise among accuracy, simplicity and efficiency, however, it will produce oscillatory solutions when the grid Reynolds numbers are large and then very fine grids are required to obtain accurate solution. The simplest first-order upwind (IUW) scheme satisfies the convective boundedness criteria, however. Its numerical diffusion is large. The power-law scheme, QMCK and second-order upwind (2UW) schemes are also often used in some commercial codes. Their numerical accurate are roughly consistent with that of ZCS. Therefore, it is meaningful to offer higher-accurate three point FV scheme. In this paper, the numerical-value perturbational method suggested by Zhi Gao is used to develop an upwind and mixed FV scheme using any higher-order interpolation and second-order integration approximations, which is called perturbational finite volume (PFV) scheme. The PFV scheme uses the least nodes similar to the standard three-point schemes, namely, the number of the nodes needed equals to unity plus the face-number of the control volume. For instanc6, in the two-dimensional (2-D) case, only four nodes for the triangle grids and five nodes for the Cartesian grids are utilized, respectively. The PFV scheme is applied on a number of 1-D problems, 2~Dand 3-D flow model equations. Comparing with other standard three-point schemes, The PFV scheme has much smaller numerical diffusion than the first-order upwind (IUW) scheme, its numerical accuracy are also higher than the second-order central scheme (2CS), the power-law scheme (PLS), the QUICK scheme and the second-order upwind(ZUW) scheme.

Una aproximación integral desde la metodología del descubrimiento del conocimiento al problema de la predicción de supervivencia en el desastre del Titanic

El objetivo de este trabajo es estudiar el Desastre del Titanic, utilizando la metodología del Descubrimiento del Conocimiento (KDD). La tesis propone diferentes variantes de cómo aplicar técnicas de Minería de Datos y herramientas del Aprendizaje Automático para predecir de forma eficiente la sobrevivencia de los pasajeros. Con este fin se han adaptado diferentes algoritmos de pre-procesamiento de datos, selección de variables y clasificación, a las características particulares del problema tratado. Algunos de estos algoritmos han sido implementados o sus implementaciones han sido modificadas para el caso específico del problema del Titanic.

Asymptotic Hyperstability of a Class of Linear Systems under Impulsive Controls Subject to an Integral Popovian Constraint

This paper is focused on the study of the important property of the asymptotic hyperstability of a class of continuous-time dynamic systems. The presence of a parallel connection of a strictly stable subsystem to an asymptotically hyperstable one in the feed-forward loop is allowed while it has also admitted the generation of a finite or infinite number of impulsive control actions which can be combined with a general form of nonimpulsive controls. The asymptotic hyperstability property is guaranteed under a set of sufficiency-type conditions for the impulsive controls.

Two new integral transforms and their applications

This thesis is in two parts. In Part I the independent variable θ in the trigonometric form of Legendre's equation is extended to the range ( -∞, ∞). The associated spectral representation is an infinite integral transform whose kernel is the analytic continuation of the associated Legendre function of the second kind into the complex θ-plane. This new transform is applied to the problems of waves on a spherical shell, heat flow on a spherical shell, and the gravitational potential of a sphere. In each case the resulting alternative representation of the solution is more suited to direct physical interpretation than the standard forms.

In Part II separation of variables is applied to the initial-value problem of the propagation of acoustic waves in an underwater sound channel. The Epstein symmetric profile is taken to describe the variation of sound with depth. The spectral representation associated with the separated depth equation is found to contain an integral and a series. A point source is assumed to be located in the channel. The nature of the disturbance at a point in the vicinity of the channel far removed from the source is investigated.

Diffraction integral formulas of the pulsed wave field in the temporal domain

To resolve the diffraction problems of the pulsed wave field directly in the temporal domain, we extend the Rayleigh diffraction integrals to the temporal domain and then discuss the approximation condition of this diffraction formula. (C) 1997 Optical Society of America.

Oscillatory integral operators related to pointwise convergence of Schrödinger operators

In this thesis we consider smooth analogues of operators studied in connection with the pointwise convergence of the solution, u(x,t), (x,t) ∈ ℝ^n x ℝ, of the free Schrodinger equation to the given initial data. Such operators are interesting examples of oscillatory integral operators with degenerate phase functions, and we develop strategies to capture the oscillations and obtain sharp L^2 → L^2 bounds. We then consider, for fixed smooth t(x), the restriction of u to the surface (x,t(x)). We find that u(x,t(x)) ∈ L^2(D^n) when the initial data is in a suitable L^2-Sobolev space H^8 (ℝ^n), where s depends on conditions on t.

Integral finite surgeries on knots in S^3

Using the correction terms in Heegaard Floer homology, we prove that if a knot in S³ admits a positive integral T-, O-, or I-type surgery, it must have the same knot Floer homology as one of the knots given in our complete list, and the resulting manifold is orientation-preservingly homeomorphic to the p-surgery on the corresponding knot.