Couverture du complexe sportif de Genk

info:eu-repo/semantics/publishe

Comparison of two different nonlinear state-space identification algorithms

In this paper, a comparison between two models for nonlinear systems is made. Both models have a state space nature, but there are some differences in the identification approach and the model structure. The first model that we will discuss is a discrete time model that uses input-output data for the identification. The second model uses explicit measurements of the states of the system and some physical insight to model the relationship between the states. The similarities and differences between the two models are discussed, and their performance is compared utilizing data from an experimental setup. © (2006) by the Katholieke Universiteit Leuven Department of Mechanical Engineering All rights reserved.status: publishe

Unilateral renal vein thrombosis and nephrotic syndrome.

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Une excroissance bizarre de l'ombilic chez un enfant de un mois

We report the case of an umbilical polyp, derived from omphalo mesenteric remnants in an one-month-old female child. This rare abnormality results from a closure defect of the vitelline duct. The vitelline duct normally closes between the 5th and the 7th weeks of intra embryonic development but can lead to several pathologies in case of closure defects, giving rise to abdominal (Meckel diverticulum, vitteline cyst) or ombilical symptoms (umbilical fistula, umbilical sinus and umbilical polyp). These desorders have a 2% incidence, and may induce clinical symptoms of varied gravity ranging from clinical silence to acute abdomen. We seized the opportunity of this rare clinical observation to review the nosology of vitellin duct defects at the light of embryologic data.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

A stochastic framework for subspace identification of a strongly nonlinear aerospace structure

The present study exploits the maximum likelihood identification framework for deriving statistically-optimal models of nonlinear mechanical systems. The identification problem is formulated in the frequency domain, and model parameters are calculated by minimising a weighted least-squares cost function. Initial values of the model parameters are obtained by means of a nonlinear subspace algorithm. The complete identification methodology is first demonstrated on a Duffing oscillator, prior to being applied to a full-scale aerospace structure

Hysteresis identification using nonlinear state-space models

Most studies tackling hysteresis identification in the technical literature follow white-box approaches, i.e. they rely on the assumption that measured data obey a specific hysteretic model. Such an assumption may be a hard requirement to handle in real applications, since hysteresis is a highly individualistic nonlinear behaviour. The present paper adopts a black-box approach based on nonlinear state-space models to identify hysteresis dynamics. This approach is shown to provide a general framework to hysteresis identification, featuring flexibility and parsimony of representation. Nonlinear model terms are constructed as a multivariate polynomial in the state variables, and parameter estimation is performed by minimising weighted least-squares cost functions. Technical issues, including the selection of the model order and the polynomial degree, are discussed, and model validation is achieved in both broadband and sine conditions. The study is carried out numerically by exploiting synthetic data generated via the Bouc-Wen equations