Browsing Τμήμα Μαθηματικών και Στατιστικής / Department of Mathematics and Statistics by Title
Now showing items 1577-1596 of 1633
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Article
Valid resampling of higher-order statistics using the linear process bootstrap and autoregressive sieve bootstrap
(2013)We show that the linear process bootstrap (LPB) and the autoregressive sieve bootstrap (AR sieve) are, in general, not valid for statistics whose large-sample distribution depends on moments of order higher than two, ...
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Article
Validating stationarity assumptions in time series analysis by rolling local periodograms
(2010)We propose a simple and powerful procedure to validate the assumption of weak stationarity in time series analysis. Our focus is on processes with a slowly varying autocovariance structure. The procedure evaluates the ...
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Article
Variable selection strategies in survival models with multiple imputations
(2007)In this paper, the variable selection strategies (criteria) are thoroughly discussed and their use in various survival models is investigated. The asymptotic efficiency property, in the sense of Shibata Ann Stat 8: 147-164, ...
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Article
Variable shape parameter Kansa RBF method for the solution of nonlinear boundary value problems
(2019)We apply a variable shape parameter Kansa–radial basis function (RBF) collocation method for the numerical solution of second and fourth order nonlinear boundary value problems in two dimensions. In the current approach, ...
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Article
Variance inequalities for covariance kernels and applications to central limit theorems
(1997)A simple estimate for the error in the CLT, valid for a wide class of absolutely continuous r.v.'s, is derived without Fourier techniques. This is achieved by using a simple convolution inequality for the variance of ...
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Article
Variational Inequalities for Arbitrary Multivariate Distributions
(1998)Upper bounds for the total variation distance between two arbitrary multivariate distributions are obtained in terms of the correspondingw-functions. The results extend some previous inequalities satisfied by the normal ...
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Book Chapter
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Article
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Conference Object
Vehicle following control design for automated highway systems
(IEEE, 1997)The purpose of this paper is to design and test a vehicle control system in order to achieve full vehicle automation in the longitudinal direction for several modes of operation, where the infrastructure manages the vehicle ...
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Article
Vektorautokorrelationen stochastischer Prozesse und die Spezifikation von ARMA-Modellen
(1990)Die Arbeit beschäftigt sich mit der Spezifikation der Ordnung von ARMA-Modellen mit Hilfe des Konzepts der Vektorautokorrelationen. Diese sind lineare Abhängigkeitsmaße zwischen Segmenten eines stochastischen Prozesses ...
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Article
Velocities for moving random surfaces
(2003)For a stationary two-dimensional random field evolving in time, we derive statistical distributions of appropriately defined velocities. The results are based on a generalization of the Rice formula. We discuss importance ...
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Article
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Article
Viscoplastic Couette Flow in the Presence of Wall Slip with Non-Zero Slip Yield Stress
(2019)The steady-state Couette flow of a yield-stress material obeying the Bingham-plastic constitutive equation is analyzed assuming that slip occurs when the wall shear stress exceeds a threshold value, the slip (or sliding) ...
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Article
Viscoplastic flow development in a channel with slip along one wall
(2017)The flow development of a Herschel–Bulkley fluid in a horizontal channel is considered assuming that slip occurs only on the upper wall due to slip heterogeneities. Hence, the velocity profile is allowed to be asymmetric ...
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Article
Viscoplastic flow development in tubes and channels with wall slip
(2016)The development of Bingham plastic flow in tubes and channels is investigated numerically using the Papanastasiou regularization and finite element simulations. It is assumed that slip occurs along the wall following ...
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Article
Viscoplastic flow in an extrusion damper
(2016)Numerical simulations of the flow in an extrusion damper are performed using a finite volume method. The damper is assumed to consist of a shaft, with or without a spherical bulge, oscillating axially in a containing ...
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Article
Viscoplastic fluids: From theory to application (VPF2009), Limassol, Cyprus, 1-5 November, 2009
(2011)
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Article
Viscoplastic Poiseuille flow in a rectangular duct with wall slip
(2014)We solve numerically the Poiseuille flow of a Herschel-Bulkley fluid in a duct of rectangular cross section under the assumption that slip occurs along the wall following a slip law involving a non-zero slip yield stress. ...
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Article
The Voltera model and its relation to the Toda lattice
(1991)An integrable system associated with a lattice deformation of the Virasoro algebra is studied. It is shown that this system, known as the Volterra model, is dynamically and algebraically equivalent to the finite non-periodic ...
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Article
Volterra's realization of the KM-system
(2007)We construct a symplectic realization of the KM-system and obtain the higher order Poisson tensors and commuting flows via the use of a recursion operator. This is achieved by doubling the number of variables through ...