Quasicrystals, model sets, and automatic sequences

We survey mathematical properties of quasicrystals, first from the point of view of harmonic analysis, then from the point of view of morphic and automatic sequences. Nous proposons un tour d'horizon de propri\'et\'es math\'ematiques des quasicristaux, d'abord du point de vue de l'analyse harmonique, ensuite du point de vue des suites morphiques et automatiques

Compositional abstraction and safety synthesis using overlapping symbolic models

In this paper, we develop a compositional approach to abstraction and safety synthesis for a general class of discrete time nonlinear systems. Our approach makes it possible to define a symbolic abstraction by composing a set of symbolic subsystems that are overlapping in the sense that they can share some common state variables. We develop compositional safety synthesis techniques using such overlapping symbolic subsystems. Comparisons, in terms of conservativeness and of computational complexity, between abstractions and controllers obtained from different system decompositions are provided. Numerical experiments show that the proposed approach for symbolic control synthesis enables a significant complexity reduction with respect to the centralized approach, while reducing the conservatism with respect to compositional approaches using non-overlapping subsystems

A "MINLP" Formulation for Optimal Design of a Catalytic Distillation Column Based on a Generic Non Equilibrium Model

This contribution proposes a Mixed Integer Non Linear Programming (MINLP) formulation for optimal design of a catalytic distillation column based on a generic nonequilibrium model (NEQ). The solution strategy for the global optimization combines Simulated Annealing (SA) and Sequential Quadratic Programming (SQP) in order to minimize the objective function. The solution of this MINLP problem yields the optimal values for the temperature, composition and flow rate profiles, tray geometry, column diameter, reflux ratio, reboiler duty, feed tray location, number of trays and catalytic stage location. Hydraulic constraints (entrainment flooding, down-flow flooding, weeping-dumpling) are also considered. For the example, the production of ETBE (Ethyl tert-butyl ether) is presented here

Sobre el caso Mexicano

El presente trabajo ofrece un breve análisis de la naturaleza del Estado mexicano en relación con la singularidad de la estructura histórica de la que surge. El surgimiento del Estado precedió a la formación de la nación. El Estado revolucionario creó la actual élite económica y organizó a los obreros y a los campesinos, colocándose como árbitro y principal actor en el gran proyecto nacional-desarrollista. Creador de la nación, mayor agencia de empleo, primer inversionista, rector de la educación y de la información, el Estado debe su estabilidad tanto a su actividad social fundamental, como a su fuerza represiva y a su monopolio político