Mines ParisTech

About: Mines ParisTech is a education organization based out in Paris, France. It is known for research contribution in the topics: Finite element method & Microstructure. The organization has 6564 authors who have published 11676 publications receiving 359898 citations. The organization is also known as: École nationale supérieure des mines de Paris & École des mines de Paris.

Globalized Nelder–Mead method for engineering optimization

Abstract: One of the fundamental difficulties in engineering design is the multiplicity of local solutions. This has triggered great efforts to develop global search algorithms. Globality, however, often has a prohibitively high numerical cost for real problems. A fixed cost local search, which sequentially becomes global is developed. Globalization is achieved by probabilistic restart. A spatial probability of starting a local search is built based on past searches. An improved Nelder-Mead algorithm makes the local optimizer. It accounts for variable bounds. It is additionally made more robust by reinitializing degenerated simplexes. The resulting method, called Globalized Bounded Nelder-Mead (GBNM) algorithm, is particularly adapted to tackle multimodal, discontinuous optimization problems, for which it is uncertain that a global optimization can be afforded. Different strategies for restarting the local search are discussed. Numerical experiments are given on analytical test functions and composite laminate design problems. The GBNM method compares favorably to an evolutionary algorithm, both in terms of numerical cost and accuracy.

The Growing Engagement of Emergent Concerned Groups in Political and Economic Life: Lessons from the French Association of Neuromuscular Disease Patients

Abstract: This article discusses the notion of emergent concerned groups and explores how these groups contribute to shaping the relations between technoscience, politics, and economic markets. The first par...

Symmetry-Preserving Observers

Abstract: This paper presents the theory of invariant observers, i.e, symmetry-preserving observers. We consider an observer to consist of a copy of the system and a correction term, and we propose a constructive method (based on the Cartan moving-frame method) to find all the symmetry-preserving correction terms. The construction relies on an invariant frame (a classical notion) and on an invariant output-error, a less standard notion precisely defined here. Using the theory we build three non-linear observers for three examples of engineering interest: a non-holonomic car, a chemical reactor, and an inertial navigation system. For each example, the design is based on physical symmetries and the convergence analysis relies on the use of invariant state-errors, a symmetry-preserving way to define the estimation error.