Now showing items 1597-1616 of 1633

    • Article  

      Wall shear rates in circular couette flow of a Herschel-Bulkley fluid 

      Chatzimina, Maria Evangelia; Georgiou, Georgios C.; Alexandrou, Andreas N. (2009)
      The objective of this work is to study quantitatively the errors introduced by the standard Newtonian and power-law assumptions used in the determination of the material properties of viscoplastic fluids from circular ...
    • Article  

      A warp-speed method for conducting Monte Carlo experiments involving bootstrap estimators 

      Giacomini, R.; Politis, Dimitris Nicolas; White, H. (2013)
      We analyze fast procedures for conducting Monte Carlo experiments involving bootstrap estimators, providing formal results establishing the properties of these methods under general conditions. © 2012 Cambridge University Press.
    • Book Chapter  

      Water management in Cyprus through a decision-support system 

      Kazeli, H.; Christofides, Tasos C.; Keravnou-Papailiou, Elpida T. (Edward Elgar Publishing, 2003)
    • Article  

      Wave energy potential in the Eastern Mediterranean Levantine Basin. An integrated 10-year study 

      Zodiatis, George; Galanis, G.; Nikolaidis, A.; Kalogeri, C.; Hayes, D.; Georgiou, Georgios C.; Chu, P. C.; Kallos, George B. (2014)
      The main characteristics of wave energy potential over Eastern Mediterranean Levantine Basin, an area of increased interest for energy resources exploration/exploitation, is presented in this work. In particular, an ...
    • Article  

      Wavelet analysis and its statistical applications 

      Abramovich, F.; Bailey, T. C.; Sapatinas, Theofanis (2000)
      In recent years there has been a considerable development in the use of wavelet methods in statistics. As a result, we are now at the stage where it is reasonable to consider such methods to be another standard tool of the ...
    • Article  

      Wavelet coefficients measuring smoothness in H p(ℝd) 

      Kyriazis, George C. (1996)
      We investigate the connection between Besov spaces and certain approximation subspaces of the Hardy spaces Hp(ℝd), 0 < p ≤ 1. In particular, we establish the wavelet decompositions for the Hp(ℝd) spaces and we characterize ...
    • Article  

      Wavelet compression and nonlinear n-widths 

      DeVore, R. A.; Kyriazis, George C.; Leviatan, D.; Tikhomirov, V. M. (1993)
      It is shown that certain algorithms of compression based on wavelet decompositions are optimal in the sense of nonlinear n-widths. © 1993 J.C. Baltzer AG, Science Publishers.
    • Article  

      Wavelet density estimation for weighted data 

      Cutillo, L.; De Feis, I.; Nikolaidou, C.; Sapatinas, Theofanis (2014)
      We consider the estimation of a density function on the basis of a random sample from a weighted distribution. We propose linear and nonlinear wavelet density estimators, and provide their asymptotic formulae for mean ...
    • Article  

      Wavelet estimators in nonparametric regression: A comparative simulation study 

      Antoniadis, Anestis; Bigot, J.; Sapatinas, Theofanis (2001)
      Wavelet analysis has been found to be a powerful tool for the nonparametric estimation of spatially-variable objects. We discuss in detail wavelet methods in nonparametric regression, where the data are modelled as ...
    • Article  

      Wavelet instruments for efficiency gains in generalized method of moment models 

      Michis, A.; Sapatinas, Theofanis (2007)
      We propose a simple computational method in the context of generalized method of moments for improving the efficiency of regression coefficient estimates. The gains in efficiency arise by incorporating additional moment ...
    • Article  

      Wavelet methods for continuous-time prediction using Hilbert-valued autoregressive processes 

      Antoniadis, Anestis; Sapatinas, Theofanis (2003)
      We consider the prediction problem of a continuous-time stochastic process on an entire time-interval in terms of its recent past. The approach we adopt is based on the notion of autoregressive Hilbert processes that ...
    • Article  

      Wavelet packet transfer function modelling of nonstationary time series 

      Nason, G. P.; Sapatinas, Theofanis (2002)
      This article shows how a non-decimated wavelet packet transform (NWPT) can be used to model a response time series, Yt in terms of an explanatory time series, Xt. The proposed computational technique transform the explanatory ...
    • Article  

      Wavelet shrinkage for natural exponential families with quadratic variance functions 

      Antoniadis, Anestis; Sapatinas, Theofanis (2001)
      We propose a wavelet shrinkage methodology for univariate natural exponential families with quadratic variance functions, covering the Gaussian, Poisson, gamma, binomial, negative binomial and generalised hyperbolic secant ...
    • Article  

      Wavelet thresholding via a Bayesian approach 

      Abramovich, F.; Sapatinas, Theofanis; Silverman, B. W. (1998)
      We discuss a Bayesian formalism which gives rise to a type of wavelet threshold estimation in nonparametric regression. A prior distribution is imposed on the wavelet coefficients of the unknown response function, designed ...
    • Article  

    • Article  

      Weak convergence of dependent empirical measures with application to subsampling in function spaces 

      Politis, Dimitris Nicolas; Romano, J. P.; Wolf, M. (1999)
      Consider the problem of inference for a parameter of a stationary time series, where the parameter takes values in a metric space (such as a function space). In this paper, we develop asymptotic theory based on subsampling ...
    • Article  

      Weakly compressible Poiseuille flows of a Herschel-Bulkley fluid 

      Taliadorou, Eleni G.; Georgiou, Georgios C.; Moulitsas, I. (2009)
      In this work, we derive approximate semi-analytical solutions of the steady, creeping, weakly compressible plane and axisymmetric Poiseuille flows of a Herschel-Bulkley fluid. Since the flow is weakly compressible, the ...
    • Article  

      Weil representations and some nonreductive dual pairs in symplectic and unitary groups 

      Pallikaros, Christakis Andrea; Zalesski, A. E. (2011)
      We study the restriction of the Weil representations of symplectic and unitary groups to subgroups that are the centralizers of certain elements, and show that these are multiplicity free. This work is along the line of ...
    • Conference Object  

      What is L1 adaptive control 

      Jafari, S.; Ioannou, Petros A.; Rudd, L. (2013)
      Recently, a class of adaptive control schemes called L1 Adaptive Control (L1-AC) has been proposed and widely advertised in aerospace control for achieving fast and robust adaptation and better performance than the existing ...
    • Article  

      The Yang-Mills Heat Semigroup on Three-Manifolds with Boundary 

      Charalambous, N.; Gross, L. (2013)
      Long time existence and uniqueness of solutions to the Yang-Mills heat equation is proven over a compact 3-manifold with smooth boundary. The initial data is taken to be a Lie algebra valued connection form in the Sobolev ...