Publications

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2015
Ramos, Luís, João Lita da Silva, and João Tiago Mexia. "On the Strong Consistency of Ridge Estimates." Communications in Statistics -­ Theory and Methods (2015).
2014
Esquível, Manuel L., João Lita da Silva, João Tiago Mexia, and Luís Ramos. "Rate of Convergence of some Asymptotic Expansions for Distribution Approximations via an Esseen Type Estimate." Communications in Statistics -­ Theory and Methods. 43.2 (2014): 266-290. AbstractWebsite

Some asymptotic expansions not necessarily related to the central limit theorem are studied. We first observe that the smoothing inequality of Esseen implies the proximity, in the Kolmogorov distance sense, of the distributions of the random variables of two random sequences satisfying a sort of general asymptotic relation. We then present several instances of this observation. A first example, partially motivated by the the statistical theory of high precision measurements, is given by a uniform asymptotic approximation to gX + nn∈, where g is some smooth function, X is a random variable and nn∈ is a sequence going to infinity; a multivariate version is also stated and proved. We finally present a second class of examples given by a randomization of the interesting parameter in some classical asymptotic formulas; namely, a generic Laplace’s type integral, randomized by the sequence nXn∈, X being a Gamma distributed random variable.

2013
Ramos, Luís P., João T. Mexia, and Pedro P. Mota. "Sample partitioning estimation for ergodic diffusions." Communications in Statistics - Simulation and Computation (2013).Website
2012
Ramos, Luís, Dário Ferreira, Sandra Saraiva Ferreira, Célia Nunes, and João Tiago Mexia. "Approximate Normality of Low Degree Polynomials in Normal Independent Variables." Far East Journal of Mathematical Sciences. 68.2 (2012): 287-296.Website
2009
Ramos, Luís, Manuel L. Esquível, João T. Mexia, and João L. Silva. "Some Asymptotic Expansions and Distribution Approximations outside a CLT Context." Proceedings of 6th St. Petersburg Workshop on Simulation. 1. 2009. 444-448. Abstract
Some asymptotic expansions non necessarily related to the central limit theorem are discussed. After observing that the smoothing inequality of Esseen implies the proximity, in the Kolmogorov distance sense, of the distributions of the random variables of two random sequences satisfying a sort of general asymptotic relation, two instances of this observation are presented. A first example, partially motivated by the the statistical theory of high precision measurements, is given by a uniform asymptotic approximation to $(g(X+ μ_n))_{n ın \mathbbm{N}}$, where $g$ is some smooth function, $X$ is a random variable having a moment and a bounded density and $(μ_{n})_{n ın \mathbbm{N}}$ is a sequence going to infinity; the multivariate case as well as the proofs and a complete set of references will be published elsewhere. We next present a second class of examples given by a randomization of the interesting parameter in some classical asymptotic formulas, namely, a generic Laplace's type integral, by the sequence $(μ_n X)_{n ın \mathbbm{N}}$, $X$ being a Gamma distributed random variable. Finally, a simulation study of this last example is presented in order to stress the quality of asymptotic approximations proposed.
2004
Ramos, Luís, Manuela Oliveira, and João T. Mexia. "Comparison, through Multiple Factorial Analysis, of treatments for Cork oak Sudden Death." Listy Biometryczne-Biometrical Letters. 41 (2004): 1-14.
Ramos, Luís, Manuela Oliveira, and João T. Mexia. "Evolution in time of sudden death of Cork oak and mached series of studies." Colloquium Biometryczne. 34a (2004): 123-130.
Ramos, Luís, Manuela Oliveira, João T. Mexia, and Christoph. Minder. "Models for series of studies with r-order common structure: application to European Union Integration." Proceedings of Summer School DATASTAT03. 15. 2004. 273-278.