Browsing by Author "Sapatinas, Theofanis"
Now showing items 41-58 of 58
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A remark on consul's (1990) counter-example
Sapatinas, Theofanis (1994)
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Short-term load forecasting: The similar shape functional time-series predictor
Paparoditis Efstathios, E.; Sapatinas, Theofanis (2013)A novel functional time-series methodology for shortterm load forecasting is introduced. The prediction is performed by means of a weighted average of past daily load segments, the shape of which is similar to the expected ...
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Signal detection in underwater sound using wavelets
Bailey, T. C.; Powell, K. J.; Krzanowski, W. J.; Sapatinas, Theofanis (1998)This article considers the use of wavelet methods in relation to a common signal processing problem, that of detecting transient features in sound recordings that contain interference or distortion. In this particular case, ...
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Some new approaches to infinite divisibility
Sapatinas, Theofanis; Shanbhag, D. N.; Gupta, A. K. (2011)Using an approach based, amongst other things, on Proposition 1 of Kaluza (1928), Goldie (1967) and, using a different approach based especially on zeros of polynomials, Steutel (1967) have proved that each nondegenerate ...
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Some properties of extreme stable laws and related infinitely divisible random variables
Radhakrishna Rao, C.; Shanbhag, D. N.; Sapatinas, Theofanis; Bhaskara Rao, M. (2009)In the course of studying the moment sequence { nn : n = 0, 1, ... }, Eaton et al. [1971. On extreme stable laws and some applications. J. Appl. Probab. 8, 794-801] have shown that this sequence, which is, indeed, the ...
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Stochastic expansions in an overcomplete wavelet dictionary
Abramovich, F.; Sapatinas, Theofanis; Silverman, B. W. (2000)We consider random functions defined in terms of members of an overcomplete wavelet dictionary. The function is modelled as a sum of wavelet components at arbitrary positions and scales where the locations of the wavelet ...
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Testing equality of autocovariance operators for functional time series
Pilavakis, Dimitrios; Paparoditis, Efstathios; Sapatinas, Theofanis (2020)We consider strictly stationary stochastic processes of Hilbert space-valued random variables and focus on fully functional tests for the equality of the lag-zero autocovariance operators of several independent functional ...
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Testing equality of spectral density operators for functional linear processes
Leucht, Anne; Paparoditis, Efstathios; Sapatinas, Theofanis (2018)The problem of testing equality of the entire second order structure of two independent functional linear processes is considered. A fully functional L2-type test is developed which evaluates, over all frequencies, the ...
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Testing for additivity and joint effects in multivariate nonparametric regression using Fourier and wavelet methods
De Canditiis, D.; Sapatinas, Theofanis (2004)We consider the problem of testing for additivity and joint effects in multivariate nonparametric regression when the data are modelled as observations of an unknown response function observed on a d-dimensional (d ≥ 2) ...
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A unified treatment for non-asymptotic and asymptotic approaches to minimax signal detection
Marteau, C.; Sapatinas, Theofanis (2015)We are concerned with minimax signal detection. In this setting, we discuss non-asymptotic and asymptotic approaches through a unified treatment. In particular, we consider a Gaussian sequence model that contains classical ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...