Now showing items 1943-1962 of 79830

  • A mathematical model to study railway track dynamics for the prediction of vibration levels generated by rail vehicles 

    Otero Yugat, Jesús; Martínez Miralles, Jordi Ramon; Santos López, M. Antonia de los; Cardona Foix, Salvador (2012-01)
    Article
    Open Access
    This article presents a mathematical model aimed at predicting wheel–rail contact vibration force arising from wheel profile irregularities. Prediction of vibrations caused by a passing train is a basic factor in environmental ...
  • A mathematical programming approach for different scenarios of bilateral bartering 

    Nasini, Stefano; Castro, Jordi; Fonseca, Pau (Institut d'Estadística de Catalunya, 2015-06)
    Article
    Open Access
    The analysis of markets with indivisible goods and fixed exogenous prices has played an important role in economic models, especially in relation to wage rigidity and unemployment. This paper provides a novel mathematical ...
  • A mathematical programming approach for different scenarios of bilateral bartering 

    Nasini, Stefano; Castro Pérez, Jordi; Fonseca Casas, Pau (Institut d'Estadística de Catalunya, 2015-01-01)
    Article
    Open Access
    The analysis of markets with indivisible goods and fixed exogenous prices has played an important role in economic models, especially in relation to wage rigidity and unemployment. This paper provides a novel mathematical ...
  • A matrix derivation of a representation theorem for (trAp)1/p 

    Neudecker, Heinz (Universitat Politècnica de Catalunya. Centre de Càlcul, 1989)
    Article
    Open Access
    A matrix derivation of a well-known representation theorem for (tr Ap)1/p is given, which is the solution of a restricted maximization problem. The paper further gives a solution of the corresponding restricted minimization ...
  • A matrix function useful in the estimation of linear continuous-time models. 

    Neudecker, Heinz (Institut d'Estadística de Catalunya, 2006)
    Article
    Open Access
    In a recent publication Chen & Zadrozny (2001) derive some equations for efficiently computing eA and ∇ eA, its derivative. They employ an expression due to Bellman (1960), Snider (1964) and Wilcox (1967) for the differential ...
  • A Max coverage formulation for information dissemination in vehicular networks 

    Trullols Cruces, Óscar; Barceló Ordinas, José María; Fiore, Marco; Casetti, Claudio; Chiasserini, Carla-Fabiana (IEEE Press. Institute of Electrical and Electronics Engineers, 2009)
    Conference lecture
    Open Access
    We consider that a given number of Dissemination Points (DPs) have to be deployed for disseminating information to vehicles travelling in an urban area. We formulate our problem as a Maximum Coverage Problem (MCP) so as ...
  • A maximum approach for robust MIMO design: combining OSTBC and beamforming with minimum transmission power requirements 

    Pascual Iserte, Antonio; Pérez Neira, Ana Isabel; Lagunas Hernandez, Miguel A. (2004)
    Conference report
    Open Access
    In this paper we address the problem of the design of a transmitter in a Multi-Input-Multi-Output (MIMO) space diversity system. We consider a design which is robust to errors in the channel estimate available at the ...
  • A maximum likelihood analysis of the RVoG model for forestry studies in polarimetric SAR interferometry 

    López Martínez, Carlos; Alonso González, Alberto (European Space Agency (ESA), 2013)
    Conference report
    Restricted access - publisher's policy
    This work analyses the validity of the RVoG model as- sumption in case of PolInSAR data in forestry analy- sis. In order to assure that the interferometric coherence describes a line, as imposed by the RVoG model, ...
  • A mean field equation on a torus: one-dimensional symmetry of solutions 

    Cabré Vilagut, Xavier; Lucia D'Agostino, Marcello; Sanchón Rodellar, Manuel (2003)
    Article
    Open Access
    We study the equation $$-\Delta u=\lambda\left(\frac{e^u}{\int_\oep e^u}- \frac{1}{|\oep|}\right)\quad \text{in }\oep$$ for $u\in E$, where $E = \{ u \in H^1(\oep): u \hbox{ is doubly periodic}, \int_{\oep} u = 0 \}$ and ...
  • A measurement method to discriminate aircraft fly-over noise 

    Genesca Francitorra, Meritxell; Romeu Garbí, Jordi; Pàmies Gómez, Teresa (2010)
    Conference report
    Restricted access - publisher's policy
    Currently aircraft noise monitoring systems use a mesh of single microphones distributed around an airport to continuously sample the noise level. This fact requires a manual process of aircraft noise event detection and ...
  • A measurement system for radiated transient electromagnetic interference based on general purpose instruments 

    Azpúrua Auyanet, Barón Marco Aurelio; Pous Solà, Marc; Silva Martínez, Fernando (Institute of Electrical and Electronics Engineers (IEEE), 2015)
    Conference report
    Open Access
    This paper presents a measurement system intended to be used to assets the radiated electromagnetic interference (EMI) in both time and frequency domains. In order to keep the measurement setup as accessible and practical ...
  • A mechanism for sandbar straightening by oblique wave incidence 

    Garnier, Roland; Falqués Serra, Albert; Calvete Manrique, Daniel; Thiebot, Jerome; Ribas Prats, Francesca (2013-06-06)
    Article
    Open Access
    Breaker bars in the surf zone of sandy beaches generally evolve between straight bars parallel to the shore and meandering crescentic bars associated with intense (dangerous) currents flowing seaward through rip channels. ...
  • A mechanism for streamwise localisation of nonlinear waves in shear flows 

    Mellibovsky Elstein, Fernando; Meseguer Serrano, Álvaro (2015-09-01)
    Article
    Open Access
    We present the complete unfolding of streamwise localisation in a paradigm of extended shear flows, namely two-dimensional plane Poiseuille flow. Exact solutions of the Navier-Stokes equations are computed numerically and ...
  • A mechanism for the generation of wave-driven rhythmic patterns in the surf zone 

    Falqués Serra, Albert; Coco, G; Huntley, D A (2000-10)
    Article
    Open Access
    The coupling between topographic irregularities and wave-driven mean water motion in the surf zone is examined. This coupling occurs because the topographic perturbations produce excess gradients in the wave radiation ...
  • A mechanism inhibiting rip channel formation for oblique waves 

    Garnier, Roland; Dodd, Nicholas; Falqués Serra, Albert; Calvete Manrique, Daniel (World Scientific Publishing Company, 2009)
    Conference lecture
    Restricted access - publisher's policy
    Previous numerical modelling studies based on 2DH morphodynamical model show that oblique waves tend to inhibit the formation of rip channel systems, but the mechanisms were not investigated. Field observations do not ...
  • A mechanism to electrically enlarge the ground plane of handset antennas: A bandwidth enhancement technique 

    Anguera, Jaume; Andújar Linares, Aurora; Puente Baliarda, Carles (2011-07)
    Article
    Restricted access - publisher's policy
    There is a need of developing new techniques for enhancing the bandwidth of handset antennas without increasing the antenna volume in order to incorporate more frequency bands into the cell phones. The technique to enhance ...
  • A medial-axis-based model for propagating cracks in a regularised bulk 

    Tamayo Mas, Elena; Rodríguez Ferran, Antonio (John Wiley & Sons, 2015-02-17)
    Article
    Open Access
    A new continuous-discontinuous strategy for the simulation of failure is presented. The continuous bulk is regularised by means of a gradient-enhanced damage model, where non-locality is introduced at the level of ...
  • A Mediterranean identity? The activity of the Mediterranean Cities Program 

    Llorach Herrero, Enric (2012)
    Conference report
    Open Access
  • A mediterranean nocturnal heavy rainfall and tornadic event. Part I: overview, damage survey and radar analysis 

    Van der Velde, Oscar Arnoud; Bech, Joan; Pineda Ruegg, Nicolau; Rigo, Tomeu; Aran, Montserrat; Amaró, Jésica; Gayà, M; Arús, J; Montañá Puig, Juan (2011-01-03)
    Article
    Restricted access - publisher's policy
    This study presents an analysis of a severe weather case that took place during the early morning of the 2nd of November 2008, when intense convective activity associated with a rapidly evolving low pressure system affected ...
  • A mediterranean nocturnal heavy rainfall and tornadic event. Part II: total lightning analysis 

    Pineda Ruegg, Nicolau; Bech, Joan; Rigo, Tomeu; Montañá Puig, Juan (2010-11-09)
    Article
    Restricted access - publisher's policy
    On the night from 1st to 2nd of November 2008, a multi-cell storm coming from the Mediterranean produced severe weather in the coastal area of Catalonia (NE Spain): groundlevel strong damaging wind gusts, a tornado – ...