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Stacked regression with restrictions

Tomasz Górecki (2005)

Discussiones Mathematicae Probability and Statistics

When we apply stacked regression to classification we need only discriminant indices which can be negative. In many situations, we want these indices to be positive, e.g., if we want to use them to count posterior probabilities, when we want to use stacked regression to combining classification. In such situation, we have to use leastsquares regression under the constraint βₖ ≥ 0, k = 1,2,...,K. In their earlier work [5], LeBlanc and Tibshirani used an algorithm given in [4]. However, in this paper...

Standard and nonstandard representability of positive uncertainty orderings

Andrea Capotorti, Giulianella Coletti, Barbara Vantaggi (2014)

Kybernetika

Axioms are given for positive comparative probabilities and plausibilities defined either on Boolean algebras or on arbitrary sets of events. These axioms allow to characterize binary relations representable by either standard or nonstandard measures (i. e. taking values either on the real field or on a hyperreal field). We also study relations between conditional events induced by preferences on conditional acts.

State-space realization of nonlinear control systems: unification and extension via pseudo-linear algebra

Juri Belikov, Ülle Kotta, Maris Tõnso (2012)

Kybernetika

In this paper the tools of pseudo-linear algebra are applied to the realization problem, allowing to unify the study of the continuous- and discrete-time nonlinear control systems under a single algebraic framework. The realization of nonlinear input-output equation, defined in terms of the pseudo-linear operator, in the classical state-space form is addressed by the polynomial approach in which the system is described by two polynomials from the non-commutative ring of skew polynomials. This allows...

Static hedging of barrier options with a smile : an inverse problem

Claude Bardos, Raphaël Douady, Andrei Fursikov (2002)

ESAIM: Control, Optimisation and Calculus of Variations

Let L be a parabolic second order differential operator on the domain Π ¯ = 0 , T × . Given a function u ^ : R and x ^ > 0 such that the support of u ^ is contained in ( - , - x ^ ] , we let y ^ : Π ¯ be the solution to the equation: L y ^ = 0 , y ^ | { 0 } × = u ^ . Given positive bounds 0 < x 0 < x 1 , we seek a function u with support in x 0 , x 1 such that the corresponding solution y satisfies: y ( t , 0 ) = y ^ ( t , 0 ) t 0 , T . We prove in this article that, under some regularity conditions on the coefficients of L , continuous solutions are unique and dense in the sense that y ^ | [ 0 , T ] × { 0 } can be C 0 -approximated, but an exact solution does not...

Static Hedging of Barrier Options with a Smile: An Inverse Problem

Claude Bardos, Raphaël Douady, Andrei Fursikov (2010)

ESAIM: Control, Optimisation and Calculus of Variations

Let L be a parabolic second order differential operator on the domain Π ¯ = 0 , T × . Given a function u ^ : R and x ^ > 0 such that the support of û is contained in ( - , - x ^ ] , we let y ^ : Π ¯ be the solution to the equation: L y ^ = 0 , y ^ | { 0 } × = u ^ . Given positive bounds 0 < x 0 < x 1 , we seek a function u with support in x 0 , x 1 such that the corresponding solution y satisfies: y ( t , 0 ) = y ^ ( t , 0 ) t 0 , T . We prove in this article that, under some regularity conditions on the coefficients of L, continuous solutions are unique and dense in the sense that y ^ | [ 0 , T ] × { 0 } can be C0-approximated, but an exact solution...

Stationarity and invertibility of a dynamic correlation matrix

Michael McAleer (2018)

Kybernetika

One of the most widely-used multivariate conditional volatility models is the dynamic conditional correlation (or DCC) specification. However, the underlying stochastic process to derive DCC has not yet been established, which has made problematic the derivation of asymptotic properties of the Quasi-Maximum Likelihood Estimators (QMLE). To date, the statistical properties of the QMLE of the DCC parameters have purportedly been derived under highly restrictive and unverifiable regularity conditions....

Stationary distribution of absolute autoregression

Jiří Anděl, Pavel Ranocha (2005)

Kybernetika

A procedure for computation of stationary density of the absolute autoregression (AAR) model driven by white noise with symmetrical density is described. This method is used for deriving explicit formulas for stationary distribution and further characteristics of AAR models with given distribution of white noise. The cases of Gaussian, Cauchy, Laplace and discrete rectangular distribution are investigated in detail.

Statistical analysis of diabetes mellitus

Hilmar Drygas (2009)

Discussiones Mathematicae Probability and Statistics

This paper deals with an application of regression analysis to the regulation of the blood-sugar under diabetes mellitus. Section 2 gives a description of Gram-Schmidt orthogonalization, while Section 3 discusses the difference between Gauss-Markov estimation and Least Squares Estimation. Section 4 is devoted to the statistical analysis of the blood-sugar during the night. The response change of blood-sugar is explained by three variables: time, food and physical activity ("Bewegung"). At the beginning...

Statistical analysis of periodic autoregression

Jiří Anděl (1983)

Aplikace matematiky

Methods for estimating parameters and testing hypotheses in a periodic autoregression are investigated in the paper. The parameters of the model are supposed to be random variables with a vague prior density. The innovation process can have either constant or periodically changing variances. Theoretical results are demonstrated on two simulated series and on two sets of real data.

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