Recursos de colección

Archivo Digital UPM (106.784 recursos)

This is an institutional repository providing access to the research output of the institution. Primarily contains thesis.

Materia = Matemáticas

Mostrando recursos 1 - 20 de 1.191

  1. Predicting recurring concepts on data-streams by me ans of a meta-model and a fuzzy similarity function

    Abad Arranz, Miguel Ángel; Gomes, João Bartolo; Menasalvas Ruiz, Ernestina
    Meta-models can be used in the process of enhancing the drift detection mechanisms used by data stream algorithms, by representing and predicting when the change will occur. There are some real-world situations where a concept reappears, as in the case of intrusion detection systems(IDS), where the same incidents or an adaptation of them usually reappear over time. In these environments the early prediction of drift by means of a better knowledge of past models can help to anticipate to the change, thus improving efficiency of the model regarding the training instances needed. In this paper we present MM-PRec, a meta-model...

  2. Antecedentes, lagunas y nuevos resultados en los conjuntos borrosos de tipo 2

    Hernández Varela, Pablo Ramón; Cubillo Villanueva, Susana; Torres Blanc, Carmen
    A partir del “Principio de Extensión” de Zadeh se han generalizado a los conjuntos borrosos de tipo 2 (T2FSs), definiciones, operaciones, propiedades y resultados obtenidos en los conjuntos borrosos (FSs). Sin embargo, como sucede en cualquier área de investigación, quedan muchas lagunas y problemas abiertos que suponen un reto para cualquiera que quiera hacer un estudio profundo en este campo. A este reto nos hemos enfrentado los autores del presente artículo, que pretende ser una exposición de algunos de los avances realizados en este sentido de "rellenar huecos" existentes en la teoría de conjuntos de tipo 2. En particular, se abordarán las negaciones que permiten hablar de la propiedad de autocontradicción, las t-normas y tconormas.

  3. Affective Mapping of Social Networks.

    Wachowicz, Monica; Iturrioz Aguirre, Teresa; Cano, Jorge; Polonia, Amelia; Pinto, Sara
    Very little is know about how the patterns of collective experiences towards a Place can quantitatively as well as qualitatively be represented based on subjective data. Therefore, our research challenge is two-fold: (a) to define what Place is by pointing to ways in which emotion states can be observed and are bound together within a social network; and (b) to develop a visual representation that provides the framework for representing patterns of emotion states associated to this Place. Towards this end, this paper will demonstrate our first results on the analysis of the correspondence obtained in the archive of Simón...

  4. High-accuracy adaptive modeling of the energy distribution of a meniscus-shaped cell culture in a Petri dish

    Gómez Revuelto, Ignacio; García Castillo, Luis E.; Pardo, David
    Cylindrical Petri dishes embedded in a rectangular waveguide and exposed to a polarized electromagnetic wave are often used to grow cell cultures. To guarantee the success of these cultures, it is necessary to enforce that the specific absorption rate distribution is sufficiently high and uniform over the Petri dish. Accurate numerical simulations are needed to design such systems. These simulations constitute a challenge due to the strong discontinuity of electromagnetic material properties involved, the relative low field value within the dish cultures compared with the rest of the domain, and the presence of the meniscus shape developed at the liquid...

  5. Esteganografía lingüística en lengua española basada en el modelo N-Gram y la ley de Zipf

    Argüelles Alvarez, Irina; Muñoz Muñoz, Alfonso
    La esteganografía lingüística es una ciencia que se aprovecha de la lingüística computacional para diseñar sistemas útiles en la protección y la privacidad de las comunicaciones digitales y en el marcado digital de textos. En los últimos años se han documentado múltiples formas de alcanzar este objetivo. En este artículo se analiza la posibilidad de generar automáticamente textos en lenguaje natural en lengua española que oculten una información dada. Se proponen una serie de hipótesis y se experimenta mediante la implementación de un algoritmo. Las pruebas realizadas indican que es factible utilizar modelos N-Gram y peculiaridades derivadas de la ley...

  6. Aplicación de los métodos de contorno en la flexión de placas

    Samartín, Avelino; Hernández Ibáñez, Santiago
    Los métodos semianalíticos poseen gran idoneidad para abordar problemas estructurales reales, obteniendo los niveles de precisión necesarios con esfuerzos de ordenador menores que los métodos exclusivamente numéricos.

  7. New patterns in human biogeography revealed by networks of contacts between linguistic groups

    Capitán Gómez, José Ángel; Axelsen, Jakob Bock; Manrubia, Susanna
    Human languages differ broadly in abundance and are distributed highly unevenly on the Earth. In many qualitative and quantitative aspects, they strongly resemble biodiversity distributions. An intriguing and previously unexplored issue is the architecture of the neighbouring relationships between human linguistic groups. Here we construct and characterize these networks of contacts and show that they represent a new kind of spatial network with uncommon structural properties. Remarkably, language networks share a meaningful property with food webs: both are quasi-interval graphs. In food webs, intervality is linked to the existence of a niche space of low dimensionality; in language networks, we...

  8. K-means algorithms for functional data

    López García, María Luz; García-Rodenas, Ricardo; González Gómez, Antonia
    Cluster analysis of functional data considers that the objects on which you want to perform a taxonomy are functions f : X e Rp ↦R and the available information about each object is a sample in a finite set of points f ¼ fðx ; y ÞA X x Rgn . The aim is to infer the meaningful groups by working explicitly with its infinite-dimensional nature. In this paper the use of K-means algorithms to solve this problem is analysed. A comparative study of three K-means algorithms has been conducted. The K-means algorithm for raw data, a kernel K-means algorithm for raw...

  9. La magie mathématique comme outil de motivation Mathematical magic as a motivational tool

    Blasco Contreras, Fernando; Duran, Josep; Duran, Miquel; Guillaumes, Laia; Miró, Joan; Simón, Silvia; Vieta, Josep Antoni
    Attracting students into STEM disciplines is a necessary task. Of course demonstrations in physics or chemistry produce interaction and with people and engage them with science. Mathematics, despite its résumé ? summary 84 inner beauty, is far away from the main public but mathematical magic performances as the main skeleton of recreational mathematics activities has been proved useful. In this talk we discuss and introduce mathematical ideas by means of magic tricks, all of them with a mathematical background. In that sense we will deal with binary numbers, bipartition method, divisibility, logical decisions, probability, geometrical dissections and topology. So, abstract...

  10. Enhanced ultrafiltration PES membranes doped with mesostructured functionalized silica particles.

    Martín, Antonio; Arsuaga, Jesús M.; Roldán, Nuria; De Abajo, Javier; Martínez Blanco, Ana; Sotto, Arcadio
    Novel hybrid ultrafiltration membranes have been prepared by incorporation of mesostructured functionalized silica particles in polyethersulfone. Physico-chemical characterization of synthesized materials was accomplished to determine the textural and structural properties of particles by nitrogen adsorption?desorption and TEM. A successful functionalization of silica with amine and carboxylic groups was confirmed by means of MAS-NMR. Membrane surface morphology was studied in terms of pore size distribution, porosity and hydrophilicity, suggesting a great influence of mesostructured silica incorporation in polyethersulfone on the polymer matrix configuration. Membrane functions were significantly improved as a result of a considerable increase of water permeation without affecting negatively...

  11. Identifying learning patterns in the upper-intermediate level of English through large-scale testing

    Argüelles Álvarez, Irina; Martínez Núñez, Margarita
    In this paper we will summarize the rationale and validation process of a multiple choice test developed at the Universidad Politécnica de Madrid (UPM) to regulate the students? access to the subject ?English for Professional and Academic Communication? for which a B2 proficiency level, in accordance with the Common European Framework of Reference for Languages (CEFRL), was established as a minimum level. Item difficulty and item discrimination are studied and analyzed from the large-scale application of the test to 924 students. The aim of the study is to reach preliminary conclusions about possible areas where sequential learning on the part...

  12. How similar can co-occurring species be in the presence of competition and ecological drift?

    Capitán Gómez, José Ángel; Cuenda, Sara; Alonso Giménez, David
    If two species live on a single resource, the one with a slight advantage will out-compete the other: complete competitors cannot coexist. This is known as the competitive exclusion principle. If no extinction occurs, it is because evolutionary adaptation to slightly different niches takes place. Therefore, it is widely accepted that ecological communities are assembled by evolutionary differentiation and progressive adaptation of species to different niches. However, some ecologists have recently challenged this classic paradigm highlighting the importance of chance and stochasticity. Using a synthetic framework for community dynamics, here we show that, while deterministic descriptors predict coexistence, species similarity...

  13. Estudio estadístico de la dilación de los grafos de proximidad: grafos Theta y Yao.

    García Leache, Gonzalo
    Construir y mantener una estructura de red eficiente es una tarea muy importante en todas aquellas redes de sensores inalámbricos. En lo que se refiere a consumo eléctrico, uno de los puntos más importantes a tener en cuenta es la potencia de transmisión que necesita cada sensor para enviar la información al siguiente nodo de la red. Con una solución donde cada sensor es capaz de reconocer a sus vecinos más próximos, estos mismos se encargarían de decidir y escoger la cantidad de potencia que desean emplear para trasmitir la información al siguiente punto. Por este motivo, el estudio y...

  14. Design and Implementation of Conchoid and Offset Processing Maple Packages

    Sendra Pons, Juana; Gómez Sánchez-Pascuala, David
    Annals of Mathematics and Artificial Intelligence presents a range of topics of concern to scholars applying quantitative, combinatorial, logical, algebraic and algorithmic methods to diverse areas of Artificial Intelligence, from decision support, automated deduction, and reasoning, to knowledge-based systems, machine learning, computer vision, robotics and planning.

  15. Grobner Basis Computation of Drazin Inverses with Multivariate Rational Function Entries

    Sendra Pons, Juana; Sendra Pons, J. Rafael
    In this paper we show how to apply Grobner bases to compute the Drazin inverse of a matrix with multivariate rational functions as entries. When the coeficients of the rational functions depend on parameters, we give suficient conditions for the Drazin inverse to specialize properly. In addition, we extend the method to weighted Drazin inverses. We present an empirical analysis that shows a good timing performance of the method.

  16. Killing Vector Fields of Generic Semi-Riemannian Metrics

    Rosado María, María Eugenia; Castrillón López, M.; Muñoz Masque, J.
    Let M be a smooth oriented connected n-dimensional manifold and let M be the space of pseudo-Riemannian metrics on M of a given signature (n+,n−),n++n−=n>1. A system of n metric invariants is attached to each metric in M, called the Ricci invariants, and by using the geometric properties of such invariants, the following result is proved: The subset O⊂M of metrics with no Killing vector fields other than the trivial one is open and dense with respect to the strong topology.

  17. Asymptotic values and analytic sets

    Canton Pire, Alicia; Qu, Jingjing
    Asymptotic values and analytic sets

  18. Spaces of holomorphic functions on non-balanced domains

    López-Salazar Codes, Jerónimo
    This paper studies the coincidence of the Tw and t$ topologies on the space of holomorphic functions defined on an open subset U of a Banach space. Dineen and Mujica proved that Tw = t$ when U is a balanced open subset of a separable Banach space with the bounded approximation property. Here, we study the tw = T$ problem for several types of non-balanced domains U.

  19. Algoritmos de gestión de personal enfocados a la mejora del servicio al cliente. Aplicación a servicios de urgencias de atención primaria

    Lantarón Sánchez, Sagrario; López González, M. Dolores; Rodrigo Hitos, Javier
    En el presente artículo se desarrolla una metodología de planificación y organización de recursos en el contexto de las urgencias de un centro de salud que puede ser extrapolada a otro tipo de servicios. Dicha metodología desemboca en la realización de un programa de ordenador que resuelve de forma efectiva ciertas tareas de planificación. Planificar los servicios de urgencias de atención primaria (SUAP) para que mejoren su calidad y sean atrayentes para los pacientes puede descongestionar las urgencias hospitalarias incidiendo de manera integral en todo el servicio de urgencias sanitario. El tiempo de espera reducido es el principal factor que los usuarios identifican con la calidad del servicio, por ello...

  20. Análisis y desarrollo de un sistema de aprendizaje en redes paralelas

    Tarrat Alcalde, María del Carmen
    Este trabajo presenta una visión general de las arquitecturas conexionistas más interesantes estudiadas hasta el momento, especificando sus características principales, así como sus ventajas y sus inconvenientes. Todas ellas poseen características similares, pero sus prestaciones son muy diferentes para cada una de las tareas que se les proponen. Se hace especial mención de una de estas arquitecturas, la Máquina de Boltzmann, cuya estructura y algoritmo de aprendizaje se estudian en detalle. La Máquina de Boltzmann puede considerarse como un tipo particular de red paralela que es capaz de aprender las restricciones que caracterizan a un dominio concreto mediante presentación de ejemplos extraídos del mismo. La red modifica los pesos de...

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