Listar Departament: Matemàtiques por título

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    • closedAccess   Reflexivity of prodiscrete topological groups  

      Galindo, Jorge; Recoder Núñez, Luis; Tkachenko, Mikhail Elsevier (2011)
      We study the duality properties of two rather different classes of subgroups of direct products of discrete groups (protodiscrete groups): P-groups, i.e., topological groups such that countable intersections of its open ...

    • openAccess   Relación entre contaminantes atmosféricos, variables meteorológicas y casos de COVID-19 en ciudades europeas 

      Vicente, Ana Belen; Chaudhuri, Somnath; Juan, Pablo; Díaz Ávalos, Carlos; Serra, Laura Congreso Nacional del Medio Ambiente (CONAMA) (2020)
      La preocupación por conocer la relación entre los niveles de contaminación del aire y las muertes por enfermedades virales no es nueva. Algunos estudios encontraron que los pacientes con SARS, un virus respiratorio ...

    • openAccess   Reliability Evaluation of the Data Acquisition Potential of a Low-Cost Climatic Network for Applications in Agriculture 

      Trilles, Sergio; Juan, Pablo; Díaz-Avalos, Carlos; Ribeiro, Sara; Painho, Marco MDPI (2020)
      Temperature, humidity and precipitation have a strong influence on the generation of diseases in different crops, especially in vine. In recent years, advances in different disciplines have enabled the deployment of sensor ...

    • openAccess   Reliability Validation of a Low-Cost Particulate Matter IoT Sensor in Indoor and Outdoor Environments Using a Reference Sampler 

      Trilles, Sergio; Vicente, Ana Belen; Juan, Pablo; Ramos, Jose Francisco; Meseguer Costa, Sergio; Serra, Laura MDPI (2019)
      A suitable and quick determination of air quality allows the population to be alerted with respect to high concentrations of pollutants. Recent advances in computer science have led to the development of a high number of ...

    • openAccess   Representation and approximation by series of continuous functions 

      Hernández, Salvador; Gassó Matoses, María Teresa; Rojas Bernilla, Esptiben Springer Verlag (2008)
      Let X be a topological space and let C (X) be the ring of all real-valued continuous functions defined on X. In this paper, we study the representation and approximation of continuous functions by sums of infinite series. ...

    • openAccess   Representation of group isomorphisms I 

      Ferrer González, María Vicenta; Gary Gutierrez, Margarita; Hernández, Salvador Elsevier (2019-08-15)
      Let G be a metric group and let Aut(G) denote the automorphism group of G. If A and B are groups of G-valued maps defined on the sets X and Y , respec- tively, we say that A and B are equivalent if there is a group ...

    • openAccess   Representation of Group Isomorphisms: The Compact Case 

      Ferrer González, María Vicenta; Gary Gutierrez, Margarita; Hernández, Salvador Hindawi Publishing Corporation (2015)
      Let 𝐺� be a discrete group and let A and B be two subgroups of 𝐺�-valued continuous functions defined on two 0-dimensional compact spaces 𝑋� and 𝑌�. A group isomorphism 𝐻� defined between A and B is called separating ...

    • openAccess   Resample-smoothing of Voronoi intensity estimators 

      Moradi, Mehdi; Cronie, Ottmar; Rubak, Ege; Lachieze-Rey, Raphael; Mateu, Jorge Springer (2019)
      Voronoi estimators are non-parametric and adaptive estimators of the intensity of a point process. The intensity estimateat a given location is equal to the reciprocal of the size of the Voronoi/Dirichlet cell containing ...

    • openAccess   Residual kriging for functional data. Application to the spatial prediction of salinity curves 

      Reyes, Adriana; Giraldo, Ramón; Mateu, Jorge Taylor & Francis (2015)
      Recently several methodologies for carrying out geostatistical analysis of functional data has been proposed. All of them assume that the spatial functional process considered is stationary. However in practice we often ...

    • closedAccess   Restrictions on maximal invariant subgroups implying solvability of finite groups 

      Beltrán, Antonio; shao, Changguo Springer Verlag (2018)
      Suppose that G and A are finite groups such that A acts coprimely on G via automorphisms. It is interesting to investigate the structure and properties of G when we impose some restrictions on its maximal A-invariant ...

    • openAccess   Revisiting Male Allies in Mathematics and Physics Throughout History: Role Models for Men in STEM Education 

      Calvo Iglesias, Encina; Epifanio, Irene MDPI (2024-05-16)
      In the academic world, there are also gender inequalities, which are especially visible in certain masculinized STEM areas, such as physics and mathematics. An essential factor in correcting these inequalities is the ...

    • closedAccess   Revisiting the random shift approach for testing in spatial statistics 

      Mrkvicka, Tomas; Dvořák, Jiří; González, Jonatan A.; Mateu, Jorge Elsevier (2020)
      We consider the problem of non-parametric testing of independence of two components of a stationary bivariate spatial process. In particular, we revisit the random shift approach that has become the standard method for ...

    • openAccess   Robust archetypoids for anomaly detection in big functional data 

      Vinue, Guillermo; Epifanio, Irene Springer (2020-08-03)
      Archetypoid analysis (ADA) has proven to be a successful unsupervised statistical technique to identify extreme observations in the periphery of the data cloud, both in classical multivariate data and functional data. ...

    • openAccess   Robust multivariate and functional archetypal analysis with application to financial time series analysis 

      Moliner Moliner, Jesús; Epifanio, Irene Elsevier (2018-12)
      Archetypal analysis approximates data by means of mixtures of actual extreme cases (archetypoids) or archetypes, which are a convex combination of cases in the data set. Archetypes lie on the boundary of the convex hull. ...

    • openAccess   Runge–Kutta–Nyström symplectic splitting methods of order 8 

      Blanes, Sergio; Casas, Fernando; Escorihuela-Tomàs, Alejandro Elsevier (2022-12)
      Different families of Runge–Kutta–Nyström (RKN) symplectic splitting methods of order 8 are presented for second-order systems of ordinary differential equations and are tested on numerical examples. They show a better ...

    • openAccess   Same-age Tutoring in Maths using ICT: From Computational Math Students to Chemistry Students 

      Gual-Arnau, Ximo; Lluch Peris, Ana María Universidad Politécnica de Valencia (2021)
      En este trabajo exponemos un proyecto educativo basado en la tutorización por pares entre estudiantado de la misma edad (same-age tutoring) que cursan la asignatura de Matemáticas I pero en dos grados diferentes como son ...

    • openAccess   Schoenberg coefficients and curvature at the origin of continuous isotropic positive definite kernels on spheres 

      Arafat, Ahmed; Gregori, Pablo; Porcu, Emilio Elsevier (2020)
      We consider the class Ψd of continuous functions that define isotropic covariance functions in the d-dimensional sphere Sd. We provide a new recurrence formula for the solution of Problem 1 in Gneiting (2013b), solved ...

    • openAccess   Schur spaces and weighted spaces of type H ∞ 

      Miralles Montolío, Alejandro Taylor & Francis (2012-11)
      We extend some results related to composition operators on Hv (G) to arbitrary linear operators on Hv0 (G) and Hv (G). We also give examples of rank-one operators on Hv(G) which cannot be approximated by composition operators

    • openAccess   Second Maximal Invariant Subgroups and Solubility of Finite Groups 

      shao, Changguo; Beltrán, Antonio Springer (2022-11-22)
      Let G be a finite group and assume that a group of automorphisms A is acting on G such that A and G have coprime orders. We prove that the fact of imposing specific properties on the second maximal A-invariant subgroups ...

    • closedAccess   Second-order analysis of anisotropic spatiotemporal point process data 

      Comas Rodríguez, Carlos; Rodríguez-Cortés, Francisco Javier; Mateu, Jorge Wiley (2015-02)
      Second-order orientation methods provide a natural tool for the analysis of spatial point process data. In this paper, we extend to the spatiotemporal setting the spatial point pair orientation distribution function. The ...