Nonparametric Bayesian Modeling for Automated Database Schema Matching

The problem of merging databases arises in many government and commercial applications. Schema matching, a common first step, identifies equivalent fields between databases. We introduce a schema matching framework that builds nonparametric Bayesian models for each field and compares them by computing the probability that a single model could have generated both fields. Our experiments show that our method is more accurate and faster than the existing instance-based matching algorithms in part because of the use of nonparametric Bayesian models

Polynomial inverse integrating factors of quadratic differential systems and other results

Consultable des del TDXTítol obtingut de la portada digitalitzadaAquesta tesi està dividida en dues parts diferents. En la primera, estudiam els sistemes quadràtics (sistemes polinomials de grau dos) que tenen un invers de factor integrant polinomial. En la segona, estudiam tres problemes diferents referits als sistemes diferencials polinomials. La primera part En l'estudi dels sistemes diferencials plans el coneixement d'una integral primera és molt important. Els seus conjunts de nivell estan formats per òrbites i ens permeten dibuixar el retrat de fase del sistema, objectiu principal de la teoria qualitativa de les equacions diferencials al pla. Com ja se sap, existeix una bijecció entre l'estudi de les integrals primeres i l'estudi dels inversos de factor integrant. De fet, és més senzill l'estudi dels inversos de factor integrant que el de les integrals primeres. Una classe és dels sistemes quadràtics àmpliament estudiada dins els sistemes diferencials al pla és la dels sistemes quadràtics. Hi ha més d'un miler d'articles publicats sobre aquest tipus de sistemes, però encara som lluny de conèixer quins d'aquests sistemes són integrables, és a dir, si tenen una integral primera. En aquest treball, estudiam els sistemes quadràtics que tenen un invers de factor integrant polinomial V = V(x, y), i per tant també tenen una integral primera, definida allà on no s'anul·la. Aquesta classe de sistemes diferencials és important per diferents motius: 1. La integral primera és sempre Darboux. 2. Conté la classe dels sistemes quàdratics homogenis, àmpliament estudiada (Date, Sibirskii, Vulpe...). 3. Conté la classe dels sistemes quàdratics amb un centre, també estudiada (Dulac, Kapteyn, Bautin,...). 4. Conté la classe dels sistemes quàdratics Hamiltonians (Artés, Llibre, Vulpe). 5. Conté la classe dels sistemes quàdratics amb una integral primera polinomial (Chavarriga, García, Llibre, Pérez de Rio, Rodríguez). 6. Conté la classe dels sistemes quàdratics amb una integral primera racional de grau dos (Cairó, Llibre). La segona part Presentam els següents tres articles: 1. A. Ferragut, J. Llibre and A. Mahdi, Polynomial inverse integrating factors for polynomial vector ?elds, to appear in Discrete and Continuous Dynamical Systems. 2. A. Ferragut, J. Llibre and M.A. Teixeira, Periodic orbits for a class of C(1) three-dimensional systems, submitted. 3. A. Ferragut, J. Llibre and M.A. Teixeira, Hyperbolic periodic orbits coming from the bifurcation of a 4-dimensional non-linear center, to appear in Int. J. Of Bifurcation and Chaos. En el primer article donam tres resultats principals. Primer provam que un camp vectorial polinomial que té una integral primera polinomial té un invers de factor integrant polinomial. El segon resultat és un exemple d'un camp vectorial polinomial que té una integral primera racional i no té ni una integral primera polinomial ni un invers de factor integrant polinomial. Era un problema obert el fet de sebre si existien camps vectorials polinomials veri?cant aquestes condicions. El tercer resultat és un exemple d'un camp vectorial polinomial que té un centre i no té invers de factor integrant polinomial. Un exemple d'aquest tipus era esperat però desconegut en la literatura. En el segon article estudiam camps vectorials polinomials reversibles de grau quatre en R(3) que tenen, sota certes condicions genèriques, un nombre arbitrari d''orbitesperi'odiques hiperb'oliques. Sense aquestes condicions, tenen un nombre arbitrari d'òrbites periòdiques hiperbòliques. Sense aquestes condicions, tenen un nombre arbitrari d'òrbites periòdiques. Finalment, en el tercer article, estudiam la pertorbació d'un centre de R(4) que prove d'un problema de la física. Mitjançant la teoria dels termes mitjans de primer ordre dins els camps vectorials polinomials de grau quatre, el sistema pertorbat pot tenir fins a setze òrbites periòdiques hiperbòliques bifurcant de les òrbites peròdiques del centre.This thesis is divided into two different parts. In the first one, we study the quadratic systems (polynomial systems of degree two) having a polynomial inverse integrating factor. In the second one, we study three different problems related to polynomial differential systems. The ?rst part. It is very important, for planar differential systems, the knowledge of a ?rst integral. Its level sets are formed by orbits and they let us draw the phase portrait of the system, which is the main objective of the qualitative theory of planar differential equations. As it is known, there is a bijection between the study of the ?rst integrals and the study of inverse integrating factors. In fact, it is easier to study the inverse integrating factors than the ?rst integrals. A widely studied class of planar differential systems is the quadratic one. There are more than a thousand published articles about this subject of differential systems, but we are far away of knowing which quadratic systems are integrable, that is, if they have a ?rst integral. In this work, we study the quadratic systems having a polynomial inverse integrating factor V = V (x, y), so they also have a ?rst integral, de?ned where V does not vanish. This class of quadratic systems is important for several reasons: 1. The ?rst integral is always Darboux. 2. It contains the class of homogeneous quadratic system, widely studied (Date, Sibirskii, Vulpe,...). 3. It contains the class of quadratic systems having a center, also studied (Dulac, Kapteyn, Bautin,...). 4. It contains the class of Hamiltonian quadratic systems (Artés, Llibre, Vulpe). 5. It contains the class of quadratic systems having a polynomial ?rst integral (Chavarriga, García, Llibre, Pérez de Rio, Rodríguez). 6. It contains the class of quadratic systems having a rational ?rst integral of de gree two (Cairó, Llibre). The classi?cation of the quadratic systems having a polynomial inverse integrating factor is not completely ?nished. There remain near a 5% of the cases to study. We leave their study for an immediate future. The second part. We present the following three articles: 1. A. Ferragut, J. Llibre and A. Mahdi, Polynomial inverse integrating factors for polynomial vector ?elds, to appear in Discrete and Continuous Dynamical Systems. 2. A. Ferragut, J. Llibre and M.A. Teixeira, Periodic orbits for a class of C(1) three-dimensional systems, submitted. 3. A. Ferragut, J. Llibre and M.A. Teixeira, Hyperbolic periodic orbits coming from the bifurcation of a 4-dimensional non-linear center, to appear in Int. J. Of Bifurcation and Chaos. In the first article we give three main results. First we prove that a polynomial vector field having a polynomial must have a polynomial inverse integrating factor. The second one is an example of a polynomial vector ?eld having a rational ?rst integral and having neither polynomial ?rst integral nor polynomial inverse integrating factor. It was an open problem to know if there exist polynomial vector ?elds verifying these conditions. The third one is an example of a polynomial vector ?eld having a center and not having a polynomial inverse integrating factor. An example of this type was expected but unknown in the literature. In the second article we study reversible polynomial vector ?elds of degree four in R(3) which have, under certain generic conditions, an arbitrary number of hyperbolic periodic orbits. Without these conditions, they have an arbitrary number of periodic orbits. Finally, in the third article, we study the perturbation of a center in R(4) which comes from a problem of physics. By the ?rst order averaging theory and perturbing inside the polynomial vector ?elds of degree four, the perturbed system may have at most sixteen hyperbolic periodic orbits bifurcating from the periodic orbits of the center

Ressenyes

Obra ressenyada: Maria Antònia MARTÍ ESCAYOL (ed.), De re rustica. Vilafranca del Penedés: Edicions i Propostes Culturals Andana, 2012

Intercambio de experiencias artísticas entre IES, un espacio abierto para la empatía y la consciencia social.

Intentando mejorar cada día como docente y trazando un camino que pueda ayudar a otros, relato aquí algunas situaciones que me he ido encontrando en el instituto y me han llevado a reflexionar. A partir de la simple idea del buen humor en la escuela y replanteando el sistema y las inercias educativas podemos pensar en humanizar la escuela. Dentro de un sistema de educación de masas dedicado a satisfacer las necesidades de la maquinaria industrial (Guiroux,1990), cada vez encontramos más interesante hacer un esfuerzo para trabajar ciertas habilidades personales que creemos necesitan los y las adolescentes. Siendo conscientes de los errores que se cometen habitualmente en educación tratamos de ir más allá de la sencilla autocorrección, en este trabajo diseñamos actividades que desarrollen la educación emocional: conceptos como la autoconsciencia, la empatía, la colaboración, la cooperación y la consciencia social, planteamos también el modo de trabajo dentro de estas actividades. Queremos mostrar algunas de estas experiencias donde tratamos de aprovechar todo el potencial de la Educación Artística para desarrollar estas capacidades. Pretendemos también crear a partir de estas actividades, un intercambio  de experiencias entre institutos para abrir sus puertas y crear lazos. Trabajando para caminar hacia nuestro sueño de cambio, debemos empezar con nuestro cambio personal. “Tornar el mundo menos feo es un deber de cada uno de nosotros” (Freire, 2006:140). Palabras clave: Educación Artística, inteligencia emocional, intercambio entre IES, empatía y conciencia social.   Abstract: Trying to improve every day as a teacher and drawling a way that can help others, here are some experiences that I’ve been finding in secondary school and have taken me to reflect. Starting with the simple idea of humour at school and rethinking the system and the educational inertias we can think about humanize school. Within a mass education system dedicated to meeting the needs of industrial machinery (Guiroux, 1990), we find more interesting increasingly make an effort to work on certain personal skills that we think adolescents need. Being aware of the mistakes usually made in education we try to go beyond the simple self-correction, in this work we design activities that develop emotional education: like self-awareness, empathy, collaboration, cooperation and social consciousness, also considering how to work within these activities. We show some of those experiences where we try to harness the full potential of Arts Education to develop these abilities. We also want create from these activities, the exchange of experiences between schools to open their doors and build bridges. Working to move towards our dream of change, we must begin with our personal change. “Render the world less ugly is the duty of each of us” (Freire, 2006:140). Keywords: Arts Education, Emotional Intelligence, interchange between schools, empathy and social consciousness

On the Darboux integrability of a cubic CRNT model in R^5

Agraïments: Portuguese National Funds through FCT - Fundacâo para a Ciência e a Tecnologia within projects PTDC/MAT/117106/2010 and PEst-OE/EEI/LA0009/2013 (CAMGSD).We study the Darboux integrability of a differential system with parameters coming from a chemical reaction model in R5. We find all its Darboux polynomials and exponential factors and we prove that it is not Darboux integrable

Rugged Iris Mechanism

A rugged iris mechanism has been designed to satisfy several special requirements, including a wide aperture in the "open" position, full obscuration in the "closed" position, ability to function in a cryogenic or other harsh environment, and minimization of friction through minimization of the number of components. An important element of the low-friction aspect of the design is maximization of the flatness of, and provision of small gaps between, adjacent iris blades. The tolerances of the design can be very loose, accommodating thermal expansions and contractions associated with large temperature excursions. The design is generic in that it is adaptable to a wide range of aperture sizes and can be implemented in a variety of materials to suit the thermal, optical, and mechanical requirements of various applications. The mechanism (see figure) includes an inner flat ring, an outer flat ring, and an even number of iris blades. The iris blades shown in front in the figure are denoted as "upper," and the iris blades shown partly hidden behind the front ones are denoted as "lower." Each iris blade is attached to the inner ring by a pivot assembly and to the outer ring by a roller/slider assembly. The upper and lower rings are co-centered and are kept in sliding contact. The iris is opened or closed by turning the outer ring around the center while holding the inner ring stationary. The mechanism is enclosed in a housing (not shown in the figure) that comprises an upper and a lower housing shell. The housing provides part of the sliding support for the outer ring and keeps the two rings aligned as described above. The aforementioned pivot assemblies at the inner ring also serve as spacers for the housing. The lower housing shell contains part of the lower sliding surface and features for mounting the overall mechanism and housing assembly. The upper housing shell contains part of the upper sliding surface