In the domain of radio frequencies, the long-range electromagnetic wave propagation is a major issue. Fast and accurate methods for propagation over several hundreds of kilometers are needed. Methods exist for this purpose but they are never both accurate and fast. The objective of this Ph.D. thesis is to develop a fast and accurate method for modeling the tropospheric propagation in 3D by means of wavelets and compression. More precisely, first, the method shall be optimized in terms of memory occupation in 2D. Then, since the method needs to be accurate, a theoretical bound of the compression error of this method shall be derived. Finally, the method must be generalized...

In this paper, we introduce new indices adapted to outputs valued in general metric spaces. This new class of indices encompasses the classical ones; in particular, the so-called Sobol indices and the Cramér-von-Mises indices. Furthermore, we provide asymptotically Gaussian estimators of these indices based on U-statistics. Surprisingly, we prove the asymp-totic normality straightforwardly. Finally, we illustrate this new procedure on a toy model and on two real-data examples.

Asymptotics deviation probabilities of the sum S n = X 1 + · · · + X n of independent and identically distributed real-valued random variables have been extensively investigated, in particular when X 1 is not exponentially integrable. For instance, A.V. Nagaev formulated exact asymptotics results for P(S n > x n) when x n > n 1/2 (see, [13, 14]). In this paper, we derive rough asymptotics results (at logarithmic scale) with shorter proofs relying on classical tools of large deviation theory and expliciting the rate function at the transition.

Over the past two decades, group signature schemes have been developed and used to enable authenticated and anonymous peer-to-peer communications. Initial protocols rely on two main authorities, Issuer and Opener, which are given substantial capabilities compared to (regular) participants, such as the ability to arbitrarily identify users. Building efficient, fast, and short group signature schemes has been the focus of a large number of research contributions. However, only a few dealt with the major privacy-preservation challenge of group signatures; this consists in providing user anonymity and action traceability while not necessarily relying on a central and fully...

Sensitivity indices are commonly used to quantity the relative inuence of any specic group of input variables on the output of a computer code. In this paper, we focus both on computer codes the output of which is a cumulative distribution function and on stochastic computer codes. We propose a way to perform a global sensitivity analysis for these kinds of computer codes. In the rst setting, we dene two indices: the rst one is based on Wasserstein Fréchet means while the second one is based on the Hoeding decomposition of the indicators of Wasserstein balls. Further, when dealing with the stochastic computer codes, we dene an ideal version of the stochastic computer code...

This paper employs the Bidirectional Encoder Representations from Transformers (BERT), a language model, fine-tuned on the question answering task, on the Aviation Safety Reporting System (ASRS) dataset’s free text reports, that describe incident occurrences in an International aviation safety context. A four-step method is used to evaluate the produced results. This paper outlines what are the limitations of this approach, as well as its usefulness in trying to extract information from thirty randomly selected free text reports when asking the following question: “When did the incident happen?”. We aim to try to integrate one of the algorithms resulting of the recent...

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The study presented in this paper has been developed with the perspective of generating long term development plans for a network of domestic airports. As a first step towards this objective, the problem of generating long term predictions of demand for a network of domestic airports is considered. This is a step towards the objective of producing long term capacity investments plans allowing to manage adequately a network of airports. Then the different demand flows at airports which are relevant to characterize the need for new airport facilities and upgardes in capacity, are analysed and compatibility constraints between these flows introduced. An appraisal is realized...

In this paper, a new application of metamaterials is put forward, the selection of the fundamental mode of waveguides. To demonstrate this new application, the Modal Expansion Theory (MET) hybridized with a 2‐D Finite Element Method (FEM) is used. The procedure to design metamaterial waveguides using the MET is also introduced. This method is used to design a corrugated waveguide with a TM01 mode as fundamental mode, knowing that in metallic waveguide the fundamental mode is the TE11. As a proof of concept, this metamaterial waveguide is fabricated as well as the metallic waveguide. Both waveguides are excited with the TE11 mode, which results in a standard propagation of...