The complexity of random ordered structures

"Vegeu el resum a l'inici del document del fitxer adjunt."

Directional discrepancy in two dimensions

In the present paper, we study the geometric discrepancy with respect to families of rotated rectangles. The well-known extremal cases are the axis-parallel rectangles (logarithmic discrepancy) and rectangles rotated in all possible directions (polynomial discrepancy). We study several intermediate situations: lacunary sequences of directions, lacunary sets of finite order, and sets with small Minkowski dimension. In each of these cases, extensions of a lemma due to Davenport allow us to construct appropriate rotations of the integer lattice which yield small discrepancy.

Contribution to Asterisk Open Source Project

With this final master thesis we are going to contribute to the Asterisk open source project. Asterisk is an open source project that started with the main objective of develop an IP telephony platform, completely based on Software (so not hardware dependent) and under an open license like GPL. This project was started on 1999 by the software engineer Mark Spencer at Digium. The main motivation of that open source project was that the telecommunications sector is lack of open solutions, and most of the available solutions are based on proprietary standards, which are close and not compatible between them. Behind the Asterisk project there is a company, Digum, which is the project leading since the project was originated in its laboratories. This company has some of its employees fully dedicated to contribute to the Asterisk project, and also provide the whole infrastructure required by the open source project. But the business of Digium isn't based on licensing of products due to the open source nature of Asterisk, but it's based on offering services around Asteriskand designing and selling some hardware components to be used with Asterisk. The Asterisk project has grown up a lot since its birth, offering in its latest versions advanced functionalities for managing calls and compatibility with some hardware that previously was exclusive of proprietary solutions. Due to that, Asterisk is becoming a serious alternative to all these proprietaries solutions because it has reached a level of maturity that makes it very stable. In addition, as it is open source, it can be fully customized to a givenrequirement, which could be impossible with the proprietaries solutions. Due to the bigness that is reaching the project, every day there are more companies which develop value added software for telephony platforms, that are seriously evaluating the option of make their software fully compatible withAsterisk platforms. All these factors make Asterisk being a consolidated project but in constant evolution, trying to offer all those functionalities offered by proprietaries solutions. This final master thesis will be divided mainly in two blocks totally complementaries. In the first block we will analyze Asterisk as an open source project and Asterisk as a telephony platform (PBX). As a result of this analysis we will generate a document, written in English because it is Asterisk project's official language, which could be used by future contributors as an starting point on joining Asterisk. On the second block we will proceed with a development contribution to the Asterisk project. We will have several options in the form that we do the contribution, such as solving bugs, developing new functionalities or start an Asterisk satellite project. The type of contribution will depend on the needs of the project on that moment.

A mixed H2/H∞-based semiactive control for vibration mitigation in flexible structures

In this paper, we address this problem through the design of a semiactive controller based on the mixed H2/H∞ control theory. The vibrations caused by the seismic motions are mitigated by a semiactive damper installed in the bottom of the structure. It is meant by semiactive damper, a device that absorbs but cannot inject energy into the system. Sufficient conditions for the design of a desired control are given in terms of linear matrix inequalities (LMIs). A controller that guarantees asymptotic stability and a mixed H2/H∞ performance is then developed. An algorithm is proposed to handle the semiactive nature of the actuator. The performance of the controller is experimentally evaluated in a real-time hybrid testing facility that consists of a physical specimen (a small-scale magnetorheological damper) and a numerical model (a large-scale three-story building)

Kuranishi type Moduli Spaces for proper CR submersions fibering over the circle

Kuranishi's fundamental result (1962) associates to any compact complex manifold X&sub&0&/sub& a finite-dimensional analytic space which has to be thought of as a local moduli space of complex structures close to X&sub&0&/sub&. In this paper, we give an analogous statement for Levi-flat CR manifolds fibering properly over the circle by describing explicitely an infinite-dimensional Kuranishi type local moduli space of Levi-flat CR structures. We interpret this result in terms of Kodaira-Spencer deformation theory making clear the likenesses as well as the differences with the classical case. The article ends with applications and examples.

Afrontamiento proactivo y bienestar psicológico en estudiantes de maestro en la Universidad de Barcelona

Las estrategias de afrontamiento utilizadas por los estudiantes desempeñan un papel relevanteen su bienestar psicológico. Este trabajo estudia la relación entre las estrategias deafrontamiento y el bienestar psicológico. La muestra está formada por 98 estudiantes de maestroentre 19 y 42 años. Se aplicaron el CRI-A (Moos, 1993) y el BSI (Derogatis y Spencer,1982). Los resultados señalan que cuanto mayor es el uso de estrategias de afrontamientomenor es la presencia de síntomas psicopatológicos, especialmente la solución de problemasy la aceptación. Y cuanto menor es el uso de estrategias de afrontamiento, como la evitacióncognitiva y la descarga emocional, mayores niveles de malestar psicológico. Las estrategias deafrontamiento funcionarían como conductas preventivas frente el estrés psicológico. Se proponea lo largo de los estudios de grado, la inclusión de estrategias de afrontamiento proactivas, como la búsqueda de soporte (mentoring, tutorías entre iguales), la resolución de problemas o la reevaluación positiva.

Afrontamiento proactivo y bienestar psicológico en estudiantes de maestro en la Universidad de Barcelona

Las estrategias de afrontamiento utilizadas por los estudiantes desempeñan un papel relevanteen su bienestar psicológico. Este trabajo estudia la relación entre las estrategias deafrontamiento y el bienestar psicológico. La muestra está formada por 98 estudiantes de maestroentre 19 y 42 años. Se aplicaron el CRI-A (Moos, 1993) y el BSI (Derogatis y Spencer,1982). Los resultados señalan que cuanto mayor es el uso de estrategias de afrontamientomenor es la presencia de síntomas psicopatológicos, especialmente la solución de problemasy la aceptación. Y cuanto menor es el uso de estrategias de afrontamiento, como la evitacióncognitiva y la descarga emocional, mayores niveles de malestar psicológico. Las estrategias deafrontamiento funcionarían como conductas preventivas frente el estrés psicológico. Se proponea lo largo de los estudios de grado, la inclusión de estrategias de afrontamiento proactivas, como la búsqueda de soporte (mentoring, tutorías entre iguales), la resolución de problemas o la reevaluación positiva.

Afrontamiento proactivo y bienestar psicológico en estudiantes de maestro en la Universidad de Barcelona

Las estrategias de afrontamiento utilizadas por los estudiantes desempeñan un papel relevanteen su bienestar psicológico. Este trabajo estudia la relación entre las estrategias deafrontamiento y el bienestar psicológico. La muestra está formada por 98 estudiantes de maestroentre 19 y 42 años. Se aplicaron el CRI-A (Moos, 1993) y el BSI (Derogatis y Spencer,1982). Los resultados señalan que cuanto mayor es el uso de estrategias de afrontamientomenor es la presencia de síntomas psicopatológicos, especialmente la solución de problemasy la aceptación. Y cuanto menor es el uso de estrategias de afrontamiento, como la evitacióncognitiva y la descarga emocional, mayores niveles de malestar psicológico. Las estrategias deafrontamiento funcionarían como conductas preventivas frente el estrés psicológico. Se proponea lo largo de los estudios de grado, la inclusión de estrategias de afrontamiento proactivas, como la búsqueda de soporte (mentoring, tutorías entre iguales), la resolución de problemas o la reevaluación positiva.