Authors:
Liang-Liang Xie,
Lennart Ljung,
Volume: 1, Page 668 Paper number 3601
Abstract:
The paper contains a discussion about what results about the quality
of an estimated model can be achieved, if no probabilistic assumptions
are introduced. Several technical results that illustrate possibilities
and difficulties are also given.
Authors:
Kun Huang,
Panganamala R. Kumar,
Volume: 1, Page 674 Paper number 3602
Abstract:
In this paper, we study several issues in motion estimation and object
recognition. First, we compare the performance of two hierarchical
and integrated methods in motion estimation. Second, we address the
use of a simulated annealing algorithm for object recognition. This
algorithm is then adapted for vehicle identification.
Authors:
Sergio Bittanti,
Marco C. Campi,
Lei Guo,
Volume: 1, Page 680 Paper number 3603
Abstract:
The identification of time varying parameters requires that a certain
level of information is present in the data through time. Only in this
case it is in fact possible to track the parameter variability and
form a reliable estimate. This consideration has led to the introduction
in the literature of a variety of persistence of excitation notions
ranging from the deterministic ones (in the 80's) to more sophisticated
stochastic definitions proposed in the last decade. This paper presents
an overview of the existing stochastic excitation notions and discuss
important issues like their necessity for tracking and their applicability
in different contexts. It appears that the present state of the art
is not completely satisfying in terms of completeness and generality
of the available results.
Authors:
Manfred Deistler,
Volume: 1, Page 685 Paper number 3604
Abstract:
In identification the problem is to attach to every string of data
of the form (equation deleted) , a system from an a priori specified
model class. Usually the model class is described by a space of free
parameters. In the fully automatized case, the system (or its free
parameters) is attached to the data by a function, (equation deleted)
say. If the data are assumed to be generated by an underlying stochastic
process (called the data generating process, DGP) and if is measurable,
then (equation deleted) is an estimator and the identification problem
is an estimation problem. The special features of system identification
arise from the rather complicated relation between external behavior,
internal system parameters and free parameters for a given model class.
Authors:
Xavier Bombois,
Michel Gevers,
Gérard Scorletti,
Volume: 1, Page 689 Paper number 3605
Abstract:
This paper presents a robustness analysis for an uncertainty set deduced
from stochastic embedding techniques and made up of ellipsoids at each
frequency in the Nyquist plane. Our robustness analysis focuses on
the validation of a controller both for robust stability and for robust
performance, over all systems in such frequency domain uncertainty
region. Our validation procedure for stability ensures that the controller
stabilizes all systems in this nonstandard uncertainty set. Our validation
procedure for performance computes the worst case performance over
all closed loop systems made up of the controller and all plants in
the frequency domain uncertainty region.
Authors:
Feng Xue,
Lei Guo,
Volume: 1, Page 695 Paper number 3606
Abstract:
We study in this paper a class of first-order continuous-time control
systems with unknown nonlinear structure and with prescribed sampling
rate h, aiming at understanding how stabilizability depends quantitatively
upon the choice of the sampling rate and the "size" of the uncertainty.
We show that if the unknown nonlinear function has a linear growth
rate with its "slope" (denoted by L) being a measure of the"size" of
uncertainty, then there exists a constant b (approx. 7.53) such that
the system is not globally stabilizable by sampled-data feedback whenever
Lh > b. Furthermore, if the unknown nonlinear function has a growth
rate faster than linear, and if the system is disturbed by noises modeled
as the standard Brownian motion, then an example is given, showing
that the corresponding sampled-data system is not stabilizable in general,
no matter how fast the sampling rate is.
Authors:
Franky De Bruyne,
Brian D.O. Anderson,
Ioan Dore Landau,
Volume: 1, Page 700 Paper number 3607
Abstract:
In this paper, we extend a family of algorithms for the identification
of continuous time nonlinear plants operating in closed-loop. The main
novelty is that the identification of unstable plants is covered in
its generality.
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