Enviaments recents

  • The origins of Zipf's meaning-frequency law 

    Ferrer Cancho, Ramon; Vitevitch, Michael S. (2018-07-30)
    Article
    Accés obert
    In his pioneering research, G.K. Zipf observed that more frequent words tend to have more meanings, and showed that the number of meanings of a word grows as the square root of its frequency. He derived this relationship ...
  • A new spectral method for latent variable models 

    Ruffini, Matteo; Casanellas Rius, Marta; Gavaldà Mestre, Ricard (2018-05-22)
    Article
    Accés restringit per política de l'editorial
    We present an algorithm for the unsupervised learning of latent variable models based on the method of moments. We give efficient estimates of the moments for two models that are well known, e.g., in text mining, the ...
  • Embedding in law of discrete time ARMA processes in continuous time stationary processes 

    Arratia Quesada, Argimiro Alejandro; Cabaña, Ana Alejandra; Cabaña Perez, Enrique (2018-12-01)
    Article
    Accés restringit per política de l'editorial
    Given any stationary time series {Xn : n ¿ Z} satisfying an ARMA(p, q) model for arbitrary p and q with infinitely divisible innovations, we construct a continuous time stationary process {xt : t ¿ R} such that the ...
  • Norm estimates for the hardy operator in terms of B-p weights 

    Boza Rocho, Santiago; Soria de Diego, Javier (2017-06-01)
    Article
    Accés obert
    We study the explicit dependence of the Bp-constant of the weight, [w]Bp , in the estimates of the norm of the Hardy operator acting on non-increasing functions in L p (w) or L p,8(w).
  • Weak-type boundedness of the Fourier transform on rearrangement invariant function spacest 

    Boza Rocho, Santiago; Soria de Diego, Javier (2018-06-08)
    Article
    Accés obert
    We study several questions about the weak-type boundedness of the Fourier transform F on rearrangement invariant spaces. In particular, we characterize the action of F as a bounded operator from the minimal Lorentz space ...
  • Optimization models of natural communication 

    Ferrer Cancho, Ramon (2018-07-03)
    Article
    Accés restringit per política de l'editorial
    A family of information theoretic models of communication was introduced more than a decade ago to explain the origins of Zipf’s law for word frequencies. The family is a based on a combination of two information theoretic ...
  • Spurious ambiguity and focalization 

    Morrill, Glyn; Valentín, Oriol (2018-06)
    Article
    Accés obert
    Spurious ambiguity is the phenomenon whereby distinct derivations in grammar may assign the same structural reading, resulting in redundancy in the parse search space and inefficiency in parsing. Understanding the problem ...
  • Characterizing approximate-matching dependencies in formal concept analysis with pattern structures 

    Baixeries i Juvillà, Jaume; Codocedo, Victor; Kaytoue, Mehdi; Napoli, Amedeo (2018-04-26)
    Article
    Accés obert
    Functional dependencies (FDs) provide valuable knowledge on the relations between attributes of a data table. A functional dependency holds when the values of an attribute can be determined by another. It has been shown ...
  • A dependency look at the reality of constituency 

    Chen, Xinying; Gómez Rodríguez, Carlos; Ferrer Cancho, Ramon (RAM-Verlag, 2018)
    Article
    Accés obert
    A comment on “Neurophysiological dynamics of phrase-structure building during sentence processing” by Nelson et al (2017), Proceedings of the National Academy of Sciences USA 114(18), E3669-E3678.
  • Global optimality in k-means clustering 

    Tîrnauca, Cristina; Gómez Pérez, Domingo; Balcázar Navarro, José Luis; Montaña Arnaiz, José Luis (2018-05-01)
    Article
    Accés restringit per política de l'editorial
    We study the problem of finding an optimum clustering, a problem known to be NP-hard. Existing literature contains algorithms running in time proportional to the number of points raised to a power that depends on the ...
  • Identifiability and transportability in dynamic causal networks 

    Blondel, Gilles; Arias Vicente, Marta; Gavaldà Mestre, Ricard (Springer, 2017-03)
    Article
    Accés obert
    In this paper, we propose a causal analog to the purely observational dynamic Bayesian networks, which we call dynamic causal networks. We provide a sound and complete algorithm for the identification of causal effects in ...
  • Thoughts about disordered thinking: measuring and quantifying the laws of order and disorder 

    Elvevaag, Brita; Foltz, Peter W.; Rosenstein, Mark; Ferrer Cancho, Ramon; Deyne, Simon De; Mizraji, Eduardo; Cohen, Alex (2017-05-01)
    Article
    Accés obert

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