Browsing Articles publicats (Matemàtica) by Title

Now showing items 148-167 of 329

    • Flow resistance equations without explicit estimation of the resistance coefficient for coarse-grained rivers 

      López Alonso, Raúl; Barragán Fernández, Javier; Colomer, M. Àngels (Maria Àngels) (Elsevier, 2007)
      The uncertainty and subjectivity inherent in estimating the resistance coeffi-cient is one of the main sources of error in the application of flow resistance equations tonatural channels. Various studies have shown that ...

    • Formal inverse integrating factors and the nilpotent center problem 

      García, I. A. (Isaac A.) (World Scientific Publishing, 2016)
      We are interested in deepening knowledge of methods based on formal power series applied to the nilpotent center problem of planar local analytic monodromic vector fields X. As formal integrability is not enough to ...

    • From expanded digraphs to lifts of voltage digraphs and line digraphs 

      Dalfó, Cristina; Fiol, Miguel Angel; Miller, Mirka; Ryan, Joe (Combinatorial Mathematics Society of Australasia (CMSA), 2017)
      In this note we present a general approach to construct large digraphs from small ones. These are called expanded digraphs, and, as particular cases, we show the close relationship between lifted digraphs of voltage digraphs ...

    • From Subkautz Digraphs to Cyclic Kautz Digraphs 

      Dalfó, Cristina (World Scientific Publishing, 2018)
      Kautz digraphs K(d, l) are a well-known family of dense digraphs, widely studied as a good model for interconnection networks. Closely related with these, the cyclic Kautz digraphs CK(d, l) were recently introduced by ...

    • Full wave analysis of stripping chronopotentiometry at scanned deposition potential (SSCP): obtaining binding curves in labile heterogeneous macromolecular systems for any metal-toligand ratio. 

      Pinheiro, José-Paulo; Galceran i Nogués, Josep; Rotureau, Elise; Companys Ferran, Encarnació; Puy Llorens, Jaume (Elsevier, 2020)
      The different deposition potentials applied in Scanned Stripping ChronoPotentiometry (SSCP) probe different values of the free metal and complex concentrations at the electrode surface. The knowledge of these concentrations ...

    • Full-wave analysis of stripping chronopotentiograms at scanned deposition potential (SSCP) as a tool for heavy metal speciation: Theoretical development and application to Cd(II)-phthalate and Cd(II)-iodide systems 

      Serrano, N.; Díaz-Cruz, J. M.; Ariño, C.; Esteban, M.; Puy Llorens, Jaume; Companys Ferran, Encarnació; Galceran i Nogués, Josep; Cecilia Averós, Joan (Elsevier, 2007)
      A new mathematical treatment has been developed and implemented in an EXCEL spreadsheet in order to determine average equilibrium functions from the full set of data measured by scanning stripping chronopotentiometry (SSCP) ...

    • Generalization of Vélu’s formulae for isogenies between elliptic curves 

      Miret, Josep M. (Josep Maria); Moreno Chiral, Ramiro; Rio, Anna (Universitat Autònoma de Barcelona. Departament de Matemàtiques, 2007)
      Given an elliptic curve E and a finite subgroup G, V ́lu’s formulae concern to a separable isogeny IG : E → E ′ with kernel G. In particular, for a point P ∈ E these formulae express the first elementary symmetric polynomial ...

    • Geometric criterium in the center problem 

      Algaba, Antonio; García, Cristóbal; Giné, Jaume (Springer Basel, 2016-10)
      In this paper we use a geometric criterium based in the classical method of the construction of Lyapunov functions to determine if a differential system has a focus or a center at a singular point. This criterium is proved ...

    • Graph Theory-Based Characterization and Classification of Household Photovoltaics 

      Ceresuela, Jesús M.; Chemisana Villegas, Daniel; López Lorenzo, Ignacio (MDPI, 2021)
      With the clear goal of improving photovoltaic (PV) technology performance towards nearly-zero energy buildings, a graph theory-based model that characterizes photovoltaic panel structures is developed. An algorithm to ...

    • Graphs, friends and acquaintances 

      Dalfó, Cristina; Fiol, Miguel Angel (Faculty of Mathematics and Natural Sciences; Institut Teknologi Bandung (ITB) Indonesia; Indonesian Combinatorial Society (InaCombS); GTA Research GroupGTA Research Group, 2018)
      A graph is a mathematical object modeling the existence of a certain relation between pairs of elements of a given set. Many of the first results concerning graphs made reference to relationships between groups of people. ...

    • Hacia un currículo basado en competencias: el caso de Colombia 

      Vanegas, Yuly Marsela; Escobar, Pilar (Graó, 2007)
      Se establecen las características principales de una propuesta curricular para las matemáticas, basada en competencias, constatando cómo se ha llegado a ésta, a partir de una reflexión de la comunidad de educadores matemáticos ...

    • Halving in some genus 2 curves over binary fields 

      Garra Oronich, Ricard; Miret, Josep M. (Josep Maria); Pujolàs Boix, Jordi (Institute of Electrical and Electronics Engineers (IEEE), 2016-06)
      We give a method to compute the halving of a divisor in the Jacobian variety of a genus 2 curve in characteristic 2. We present explicit halving formulae for each possible divisor class for some curves (those with h (x)= ...

    • Harvester ant nest distribution depends on soil disturbance regime 

      Baraibar Padró, Bàrbara; Torra Farré, Joel; Royo-Esnal, Aritz; Recasens i Guinjuan, Jordi; Comas Rodríguez, Carles (Elsevier, 2018-09-17)
      Nest densities of harvester ants (Messor barbarus) are high in rain-fed cereal fields in north-eastern Spain where the ants remove large quantities of seeds, contributing to reductions in weed populations. The distribution ...

    • Herramienta para evaluar trayectorias de aprendizaje de la medida de longitud en niños de 6-8 años 

      Rubio Franco, Alba; Vanegas, Yuly Marsela; Prat Moratonas, Montserrat (Universidad de Valladolid, 2018)
      Este artículo presenta el diseño y construcción de una herramienta para la caracterización de trayectorias de aprendizaje de la medida de longitud en niños de 6-8 años. El proceso seguido ha permitido configurar y validar ...

    • Herramientas virtuales de simulación en la enseñanza de la astronomía diurna en futuros maestros de Primaria 

      Ibáñez, Manuel; Estrada Roca, M. Asunción; Barbero Sola, Iván (Edutec. Asociación para el Desarrollo de la Tecnología Educativa, 2017-03-01)
      Este trabajo presenta el impacto de la incorporación de herramientas virtuales de simulación de libre distribución combinadas con un modelo instruccional constructivista y dialógico en la docencia de la astronomía diurna ...

    • Higher Accuracy of Lung Ultrasound over Chest X-ray for Early Diagnosis of COVID-19 Pneumonia 

      Martínez Redondo, Javier; Comas Rodríguez, Carles; Pujol Salud, Jesús; Crespo Pons, Montserrat; García Serrano, Cristina; Ortega Bravo, Marta; Palacín Peruga, Jose María (MDPI, 2021)
      Background: The COVID-19 pandemic rapidly strained healthcare systems worldwide. The reference standard for diagnosis is a positive reverse transcription polymerase chain reaction (RTPCR) test, but results are not immediate ...

    • Highest weak focus order for trigonometric Liénard equations 

      Gasull, Armengol; Giné, Jaume; Valls, Claudia (Springer, 2020)
      Given a planar analytic differential equation with a critical point which is a weak focus of order k, it is well known that at most k limit cycles can bifurcate from it. Moreover, in case of analytic Liénard differential ...

    • Human-caused fire occurrence modelling in perspective: a review 

      Costafreda Aumedes, Sergi; Comas Rodríguez, Carles; Vega García, Cristina (CSIRO Publishing, 2017)
      The increasing global concern about wildfires, mostly caused by people, has triggered the development of human-caused fire occurrence models in many countries. The premise is that better knowledge of the underlying factors ...

    • Identifying codes in line digraphs 

      Balbuena Martínez, Camino; Dalfó, Cristina; Martínez Barona, Berenice (Elsevier, 2020-05-21)
      Given an integer ≥1, a (1, ≤ )-identifying code in a digraph is a dominating subset C of vertices such that all distinct subsets of vertices of cardinality at most have distinct closed in-neighborhoods within C . In ...

    • Idoneidad didáctica en educación infantil: matemáticas con robots Blue-Bot 

      Ricart Aranda, Maria; Estrada Roca, M. Asunción; Margalef Martíl, María (Universidad de Córdoba, 2019)
      El objetivo de este trabajo es valorar la idoneidad didáctica de un proceso de enseñanza y aprendizaje de orientación espacial con el robot Blue-Bot. Primero, se contextualiza la experiencia innovadora implementada con ...