Search results for "optimization"
showing 10 items of 2824 documents
Étude de statistiques combinatoires et de leur impact en optimisation évolutionnaire
2021
This thesis studies combinatorial objects, with both an algorithmic and a combinatorial point of view. In the combinatorial part, we take care first, the enumeration of Catalan words avoiding pairs of patterns of length three, presenting the proofs of each case with various enumeration methods. Catalan words are particular growth-restricted words counted by the eponymous integer sequence. More precisely, we systematically explore the structural properties of the sets of words under consideration and give enumerating results by constructive bijections or bivariate generating functions with respect to the length and descent number. Then, we study a sorting machine using two stacks in s…
Refitting solutions promoted by $\ell_{12}$ sparse analysis regularization with block penalties
2019
International audience; In inverse problems, the use of an $\ell_{12}$ analysis regularizer induces a bias in the estimated solution. We propose a general refitting framework for removing this artifact while keeping information of interest contained in the biased solution. This is done through the use of refitting block penalties that only act on the co-support of the estimation. Based on an analysis of related works in the literature, we propose a new penalty that is well suited for refitting purposes. We also present an efficient algorithmic method to obtain the refitted solution along with the original (biased) solution for any convex refitting block penalty. Experiments illustrate the g…
Geometric and numerical methods in optimal control for the time minimal saturation in Magnetic Resonance
2018
International audience
Geometric Optimal Control of the Generalized Lotka-Volterra Model with Applications Controlled Stability of Microbiota
2022
International audience; In this talk we present the Generalized Lotka–Volterra dynamics associated to themodel of C-difficile infection of the intestine microbiote and aiming to transfer the systemfrom an infected state to an healthy state. The control inputs are of two types : fecalinjection or bactericides which act as Dirac pulses and prebiotics or antibiotics which act ascontinuous controls. An uniform frame can be introduced using the tools from geometriccontrol to analyze the accessibility set as the orbit of a pseudo-semi group. Optimalcontrol can be considered in the frame of permanent control or sampled-data control. Thelater being adapted to the practical constraints of a finite s…
Lunar perturbation of the metric associated to the averaged orbital transfer
2014
International audience; In a series of previous article we introduced a Riemannian metric associated to the energy minimizing orbital transfer with low propulsion. The aim of this article is to study the deformation of this metric due to the perturbation caused by the lunar attraction. Using Hamiltonian formalism, we describe the effects of the perturbations on the orbital transfers and the deformation of the conjugate and cut loci of the original metric.
Optimization of chemical batch reactors using temperature control
2019
International audience
Sub-Riemannian Geometry and swimming at low Reynolds number
2017
International audience
Numerical Approach to the Optimal Control and Efficiency of the Copepod Swimmer
2016
International audience
Averaging for minimum time control problems and applications
2017
International audience
Optimal control theory, sub-Riemannian geometry and swimming of copepod
2017
International audience