Convergence Rate of Nonlinear Switched Systems

This paper is concerned with the convergence rate of the solutions of nonlinear switched systems. We first consider a switched system which is asymptotically stable for a class of inputs but not for all inputs. We show that solutions corresponding to that class of inputs converge arbitrarily slowly to the origin. Then we consider analytic switched systems for which a common weak quadratic Lyapunov function exists. Under two different sets of assumptions we provide explicit exponential convergence rates for inputs with a fixed dwell-time

Stability of uniformly bounded switched systems and Observability

This paper mainly deals with switched linear systems defined by a pair of Hurwitz matrices that share a common but not strict quadratic Lyapunov function. Its aim is to give sufficient conditions for such a system to be GUAS.We show that this property of being GUAS is equivalent to the uniform observability on $[0,+\infty)$ of a bilinear system defined on a subspace whose dimension is in most cases much smaller than the dimension of the switched system.Some sufficient conditions of uniform asymptotic stability are then deduced from the equivalence theorem, and illustrated by examples.The results are partially extended to nonlinear analytic systems

Why Do So Many Underdeveloped Economies Seem Not to Develop? The Impact of Public Social Governance

In the early 1980s, over 2.1 billion people were facing a hopeless future by getting by on less than $3.10 a day (and sometimes as little as$1.90 a day) despite living in a world of over-abundance. Given the impact of indigence on world stability and human solidarity, winning the fight against poverty is a critical issue for all people, whether rich or poor. Using proxies representing social and political pressures faced by governments striving toward development, we measure the impact of public governance on poverty decrease. We explain why most poor countries seem to be failing in their development initiatives, or, at the very least, are caught in an impasse. Using a sample of 177 countries in 2016, regressions are run to test the impact of public social governance on poverty. On average, poor countries underperform compared to rich ones. We suggest why weak public social governance can be a serious impediment to national development

Les défis de la régionalisation

¿Cuáles son las dificultades y los desafíos que se generan en torno al proceso de regionalización de Marruecos? ¿Es posible una regionalización avanzada en el país teniendo en cuenta toda una serie de paradigmas de carácter histórico, social, político y democrático a los cuales debería responder? Estas son algunas de las preguntas clave a las que se responde en esta comunicación. Del mismo modo, se analiza cómo es posible una gestión democrática de la diversidad regional y territorial marroquí, a través de instancias con legitimidad política y frente a una clara y vigente disfunción del aparato estatalWhat are the difficulties and challenges that arise on the process of regionalization of Morocco? It is possible an advanced regionalization in Morocco taking into account a variety of paradigms of historical, social, political and democratic background? These are some of the key questions that are answered in this communication. In the same way, this paper analyse how is it possible the democratic management of the regional and territorial diversity of Morocco, through political legitimacy and facing a clear and effective state apparatus dysfunctio

Effect of the Mg/Al ratio and of the rate of reinforcement on the synthesis of a nanocomposite Cellulose/Hydrotalcite

The objective of this work is to synthesize a nonmaterial by introducing synthetic clay (hydrotalcite) as a nanofiller in a natural polymer matrix (cellulose) and to study the effect of Mg/Al ratio and the rates of reinforcement.Cellulose fibers were extracted from ‘Yucca‘ tree’s leaves by a chemical treatment and Hydrotalcite (MgAlCO3) was synthesized by the method of co-precipitation at fixed pH with a ratio of Mg/Al=2 or 3.The composite materials were elaborated by microwave activation.The Hydrotalcites with an Mg/Al ratio = 2 or 3 were tested as well as various rates of reinforcement (2, 5 or 10% Hydrotalcite) in order to optimize conditions of obtaining a nanomaterial. The structures of obtained materials were characterized by IR spectroscopy, X-ray Diffraction and Transmission Electron Microscopy. The thermal stability was analyzed by TG-DTA analyses.The characterizations carried out on these compounds revealed structural modifications in agreement with the formation of a nanomaterial (cellulose/Hydrotalcite) with the improved thermal properties