All Years Seminars
[INMA] 2008-03-11 (14.00) : Near optimal and reverse time interval observers. Application to uncertain bioreactors
At Euler building
Speaker :
Marcelo MOISAN
( INRIA-Sophia Antipolis
)
Abstract :
In this seminar we propose a new interval observer for the estimation
of unmeasured variables of uncertain bioreactors. The observer is based on a class
of bounded error observers, that make use of a loose approximation of the bacterial
kinetics. We first show how to generate guaranteed upper and lower bounds on the unknown
state, provided that known intervals for the initial condition and the uncertainties are available.
An optimality criterion is then introduced, leading to the definition of an optimal observer.
We show that this criterion allows to determine a set of gains which generates the best
estimates. We extend the observer design introducing reverse time interval
observers. We show that running observers in reverse time improves dramatically the
convergence rate, through a discontinuous interval estimation procedure.
The method is applied to the estimation of the total biomass of an industrial wastewater
treatment plant, demonstrating its efficiency.
[INMA] 2008-03-04 (14.00) : A framework of calculus on facial surfaces : Analysis representation and comparison
At Euler building
Speaker :
Samir, Chafik
Abstract :
There is an increasing interest in analyzing shapes of facial surfaces with many applications including biometrics, facial surgery, video communications, and 3D animation. This interest is fuelled by the advent of different types of scanners that can provide high-resolution measurements of both geometry and texture of human facial surfaces.
One general goal in this work is to develop computational tools for analyzing 3D face data. In particular, we are interested in comparing the shapes of facial surfaces. Such a tool can be used to recognize human beings according to their facial shapes, to measure changes in a facial shape due to a surgery, or to study/capture the variations in facial shapes during conversations and expressions of emotions.
Additionally, another subproblem addressed in here is to find an optimal deformation of one surface into another, under some chosen criterion. These deformations can be useful in defining summary statistics of a collection of faces. For example, we define and compute an it average face (Karcher mean) of a set of people, or for one person under different facial expressions.
Efficient tools for understanding and studying variability in facial shapes are of great importance in our biometric-oriented society, our method using
planar shapes is tested on FRGC v1.0 database, and obtained results are very promising.
[INMA] 2008-02-26 (14.00) : Régulation de la température du réacteur tubulaire à l'intérieur du réacteur chimique tubulaire.
At Euler building
Speaker :
Nadia BENIICH
(University of El Jadida/CESAME
)
Abstract :
On s'intéresse dans cet exposé à la régulation de la température des réacteurs tubulaires exothermiques à dispersion axiale
et piston dont la dynamique est décrite par des équations aux dérivées partielles non linéaires, en utilisant des commandes aux
bords soumises à des contraintes. Nous proposons quelques contrôleurs adaptatifs qui permettent de conduire la température
du réacteur à l'intérieur dun voisinage d'un profil de référence de rayon ? arbitraire et suffisamment petit.
[INMA] 2008-02-21 (16.00) : JEUDI !! THESE DE DOCTORAT "Dominant vectors of nonnegative matrices. Application to information extraction in large graphs".
At BARB93
Speaker :
Ninove, Laure
Abstract :
Objects such as documents, people, words or utilities, that are related in
some way, for instance by citations, friendship, appearance in definitions
or physical connections, may be conveniently represented using graphs or
networks. An increasing number of such relational databases, as for instance
the World Wide Web, digital libraries, social networking web sites or phone
calls logs, are available. Relevant information may be hidden in these
networks. A user may for instance need to get authority web pages on a
particular topic or a list of similar documents from a digital library, or
to determine communities of friends from a social networking site or a phone
calls log. Unfortunately, extracting this information may not be easy.
This thesis is devoted to the study of problems related to information
extraction in large graphs with the help of dominant vectors of nonnegative
matrices. The graph structure is indeed very useful to retrieve information
from a relational database. The correspondence between nonnegative matrices
and graphs makes Perron-Frobenius methods a powerful tool for the analysis
of networks.
In a first part, we analyze the fixed points of a normalized affine
iteration used by a database matching algorithm. Then, we consider questions
related to PageRank, a ranking method of the web pages based on a random
surfer model and used by the well known web search engine Google. In a
second part, we study optimal linkage strategies for a web master who wants
to maximize the average PageRank score of a web site. Finally, the third
part is devoted to the study of a nonlinear variant of PageRank. The simple
model that we propose takes into account the mutual influence between web
ranking and web surfing.
[INMA] 2008-02-14 (14.00) : JEUDI!! THESE DE DOCTORAT "Graphs and networks for the analysis of autonomous agent systems".
At BARB93
Speaker :
Hendrickx, Julien
Abstract :
Seminars
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