Ensenada Center for Scientific Research and Higher Education

About: Ensenada Center for Scientific Research and Higher Education is a facility organization based out in Ensenada, Mexico. It is known for research contribution in the topics: Population & Nonlinear system. The organization has 1934 authors who have published 3733 publications receiving 63115 citations.

Finite Time Stability and Quasihomogeneous Control Synthesis of Uncertain Switched Systems with Application to Underactuated Manipulators

Abstract: Switched control synthesis is developed for underactuated mechanical systems. In order to locally stabilize an underactuated system around an unstable equilibrium, its output is specified in such a way that the corresponding zero dynamics is locally asymptotically stable. Once such an output has been chosen, the desired stability property of the closed-loop system is provided by applying a quasihomogeneous switched controller, driving the system to the zero dynamics manifold in finite time. Although the present synthesis exhibits an infinite number of switches on a finite time interval, it does not rely on the generation of sliding modes, while providing robustness features similar to those possessed by their sliding mode counterparts. Theoretical results are supported by an application to drive systems with backlash.

A Description of Geostrophic Gyres in the Southern Gulf of California

Abstract: Historical hydrographic data are used to investigate the geostrophic circulation in the Southern Gulf of California, focusing on the description of evidences supporting the existence of gyres. It is found that the horizontal dimensions and sense of rotation of the gyres are variable, and that their position are not tied to basins and sills as has been previously proposed. In the vertical, the gyres reach at least 500 meters, and probably 1000 meters. A seasonal behavior cannot be ascertained due to data limitation.

On stability of linear parabolic distributed parameter systems with time-varying delays

Abstract: Lyapunov-Krasovskii method is extended to linear parabolic time-delay systems in a Hilbert space. The operator acting on the delayed state is supposed to be bounded. The system delay is admitted to be unknown and time-varying with an a priori known upper bound on the delay derivative. Sufficient delay-independent/delay-dependent stability conditions are derived in the form of linear operator inequalities, where the decision variables are operators in the Hilbert space. Being applied to a heat equation, these conditions are represented in terms of standard linear matrix inequalities.

Stochastic theory of dynamic permeability in poroelastic media.

Abstract: A theory for the dynamic permeability in deformable porous media is developed. The analysis is based on the momentum flux transfer from the slow compressional into the slow shear wave (a proxy for the viscous wave in a Newtonian fluid) in the presence of random pore-scale heterogeneities. A first-order statistical smoothing approximation is used to infer a dynamic permeability in the form of an integral over the covariance function modulated by the slow shear wave. In a smooth pore-throat limit the results reproduce the model proposed by Johnson et al. [J. Fluid Mech. 176, 379 (1987)].