Ara es mostren els elements 1-20 de 290

    • Modeling inertia through the interaction with quantum fluctuations 

      Giné, Jaume; Gaetano Luciano, Giuseppe (Elsevier, 2021)
      The origin of inertia of macroscopic bodies has never been thoroughly elucidated. In this paper we provide a new explanation based on the following assumptions: (i) we can think of any body as being composed by resonant ...
    • On the Laplacian spectra of token graphs 

      Dalfó, Cristina; Duque, F.; Fabila Monroy, R.; Fiol, Miguel Angel; Huemer, Clemens; Zaragoza Martínez, F.J.; Trujillo Negrete, A.L. (Elsevier, 2021)
      We study the Laplacian spectrum of token graphs, also called symmetric powers of graphs. The k-token graph Fk(G) of a graph G is the graph whose vertices are the k-subsets of vertices from G, two of which being adjacent ...
    • A New Normal Form for Monodromic Nilpotent Singularities of Planar Vector Fields 

      Algaba, Antonio; García, Cristóbal; Giné, Jaume (Springer, 2021)
      In this work, we present a new technique for solving the center problem for nilpotent singularities which consists of determining a new normal form conveniently adapted to study the center problem for this singularity. In ...
    • Designing e-commerce supply chains: a stochastic facility–location approach 

      Pagès Bernaus, Adela; Ramalhinho-Lourenço, Helena; Juan Pérez, Ángel A.; Calvet Liñan, Laura (Wiley, 2017-07)
      e-Commerce activity has been increasing during recent years, and this trend is expected to continue in thenear future. e-Commerce practices are subject to uncertainty conditions and high variability in customers’demands. ...
    • Pirámides indexadas y disimilaridades piramidales 

      Capdevila Marqués, Carles; Arcas Pons, Antoni (Institut d'Estadística de Catalunya, 1995)
      En este trabajo se pretende una formalización de las bases matemáticas sobre las que se amparan los modelos de clasificación y representación piramidal, estableciéndose para ello una relación entre los conceptos de pirámide ...
    • Empirical significance test of the goodness-of-fit for some pyramidal clustering procedures 

      Capdevila Marqués, Carles; Arcas Pons, Antoni (Institut d'Estadística de Catalunya, 1995)
      Through a series of simulation tests by Monte Carlo methods, some aspects relating to the inference concerning pyramidal trees built by the maximum and minimum methods are considered. In this sense, the quantiles of the ...
    • Modelling the SARS-COV-2 outbreak: assessing the usefulness of protective measures to reduce the pandemic at population level 

      Colomer, M. Àngels (Maria Àngels); Margalida, Antoni; Alòs, Francesc; Oliva-Vidal, Pilar; Vilella, Anna; Fraile Sauce, Lorenzo José (Elsevier, 2021)
      A new bioinspired computational model was developed for the SARS-CoV-2 pandemic using the available epidemiological information, high-resolution population density data, travel patterns, and the average number of contacts ...
    • The Risk of Hospitalization in COVID-19 Patients Can Be Predicted by Lung Ultrasound in Primary Care 

      Martínez Redondo, Javier; Comas Rodríguez, Carles; Pujol Salud, Jesús; Crespo Pons, Montserrat; García-Serrano, Cristina; Ortega Bravo, Marta; Palacín Peruga, Jose María (MDPI, 2021)
    • Distance-based topological polynomials associated with zero-divisor graphs 

      Ahmad, Ali; López Masip, Susana-Clara (Hindawi, 2021-05)
      Let R be a commutative ring with nonzero identity and let Z(R) be its set of zero divisors. The zero-divisor graph of R is the graph T(R) with vertex set V(T(R))=Z(R)*, where Z(R)*=Z(R)\{0} , and edge set E(T(R))={{x,y}:x·y=0} ...
    • Center problem and ν-cyclicity of polynomial zero-Hopf singularities with non-singular rotation axis 

      García, I. A. (Isaac A.) (Elsevier, 2021-06-02)
      We consider three-dimensional polynomial families of vector fields parameterized by the admissible coefficients having a fixed zero-Hopf equilibrium and a non-singular rotation axis through it. We are interested in the ...
    • Some remarks on global analytic planar vector fields possessing an invariant analytic set 

      García, I. A. (Isaac A.) (Taylor and Francis, 2021-02-01)
      We study the problem of determining the canonical form that a planar analytic vector field in all the real plane can have in order to possess a given invariant analytic set. We determine some conditions that guarantee that ...
    • Economic assessment of pig meat processing and cutting production by simulation 

      Pla Aragonés, Lluís Miquel; Pagès Bernaus, Adela; Nadal Roig, Esteve; Mateo Fornés, Jordi; Tarrafeta, Pedro; Mendioroz, Daniel; Pérez Cànovas, Lorea; López Nogales, Sandy (Walter de Gruyter, 2019-04)
      This paper presents the development and adoption of a discrete event simulation model of a pig meat-packing plant located in Navarre (Spain). The simulation model was developed to represent all the tasks and pig meat cuts ...
    • Minimum tree decompositions with a given tree as a factor 

      Lladó, Anna; López Masip, Susana-Clara (Combinatorial Mathematics Society of Australasia, 2005)
      A tree decomposition of a graph G is a family of subtrees whose sets of edges partition the set of edges of G. In this paper we are interested in the structure of the trees involved in tree decompositions with the minimum ...
    • Modeling of Vaccination and Contact Tracing as Tools to Control the COVID-19 Outbreak in Spain 

      Colomer, M. Àngels (Maria Àngels); Margalida, Antoni; Alòs, Francesc; Oliva-Vidal, Pilar; Vilella, Anna; Fraile Sauce, Lorenzo José (MDPI, 2021)
      We developed an agent-based stochastic model, based on P Systems methodology, to decipher the effects of vaccination and contact tracing on the control of COVID-19 outbreak at population level under different control ...
    • Vanishing set of inverse Jacobi multipliers and attractor/repeller sets 

      García, I. A. (Isaac A.); Giné, Jaume; Llibre, Jaume; Maza Sabido, Susanna (American Institute of Physics, 2021-01-01)
      In this paper we study conditions under which the zero-set of the inverse Jacobi multiplier of a smooth vector field contains its attractor/repeller compact sets. The work generalizes previous results focusing on sink ...
    • Decompositions of a rectangle into non-congruent rectangles of equal area 

      Dalfó, Cristina; Fiol, Miguel Angel; López Lorenzo, Ignacio; Martínez Pérez, Álvaro (Elsevier, 2021-06)
      In this paper, we deal with a simple geometric problem: Is it possible to partition a rectangle into k non-congruent rectangles of equal area? This problem is motivated by the so-called 'Mondrian art problem' that asks a ...
    • 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 ...
    • 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 ...
    • Evaluation of Replacement Policies in Sow Farms Using ArenaTM Simulation Software 

      Montufar Benítez, Marco Antonio; Pla Aragonés, Lluís Miquel; Serrato Garcia, Marco A.; Montaño Arango, Oscar; Corona Armenta, José Ramón (Scientific Research Publishing Inc., 2014)
      This paper presents an application of the simulation of discrete events (SED) using ARENATM in the management of large-scale breeding farms. The main objective of the simulation model is to find a policy of replacement, ...
    • Prospective Primary School Teachers’ Attitudes towards Probability and its Teaching 

      Estrada Roca, M. Asunción; Batanero, Carmen (Modestum Publishing Ltd., 2020)
      Since probability is a new topic at the primary school level in many countries, many primary school teachers may consider themselves not well prepared or may not value the formative role of probability as a topic for their ...