64,520 research outputs found
A metaheuristic particle swarm optimization approach to nonlinear model predictive control
This paper commences with a short review on
optimal control for nonlinear systems, emphasizing the Model
Predictive approach for this purpose. It then describes the Particle Swarm Optimization algorithm and how it could be applied
to nonlinear Model Predictive Control. On the basis of these
principles, two novel control approaches are proposed and anal-
ysed. One is based on optimization of a numerically linearized
perturbation model, whilst the other avoids the linearization step
altogether. The controllers are evaluated by simulation of an
inverted pendulum on a cart system. The results are compared
with a numerical linearization technique exploiting conventional
convex optimization methods instead of Particle Swarm Opti-
mization. In both approaches, the proposed Swarm Optimization
controllers exhibit superior performance. The methodology is
then extended to input constrained nonlinear systems, offering a
promising new paradigm for nonlinear optimal control design.peer-reviewe
Multilayer perceptron adaptive dynamic control of mobile robots : experimental validation
This paper presents experimental results acquired from the implementation of an adaptive control scheme for nonholonomic mobile robots, which was recently proposed by the same authors and tested only by simulations. The control system comprises a trajectory tracking kinematic controller, which generates the reference wheel velocities, and a cascade dynamic controller, which estimates the robot's uncertain nonlinear dynamic functions in real-time via a multilayer perceptron neural network. In this manner precise velocity tracking is attained, even in the presence of unknown and/or time-varying dynamics. The experimental mobile robot, designed and built for the purpose of this research, is also presented in this paper.peer-reviewe
On the Linearization of the First and Second Painleve' Equations
We found Fuchs--Garnier pairs in 3X3 matrices for the first and second
Painleve' equations which are linear in the spectral parameter. As an
application of our pairs for the second Painleve' equation we use the
generalized Laplace transform to derive an invertible integral transformation
relating two its Fuchs--Garnier pairs in 2X2 matrices with different
singularity structures, namely, the pair due to Jimbo and Miwa and the one
found by Harnad, Tracy, and Widom. Together with the certain other
transformations it allows us to relate all known 2X2 matrix Fuchs--Garnier
pairs for the second Painleve' equation with the original Garnier pair.Comment: 17 pages, 2 figure
Magistrates, patrons and benefactors of voluntary associations: status building and Romanisation in the Spanish, Gallic and German Provinces of the Roman Empire
Social historians are becoming increasingly aware that voluntary associations provide the ‘missing link’ between the civic elites and the ‘lower classes’. This raises an important question: how did the Roman collegia contribute to the Romanisation of the (Western) provinces ? Romanisation is the outcome of a confrontation between cultures. There are major differences between provinces in how Romanisation took place. I will argue that status-achievement through collegia was markedly more significant in the Gallic and German provinces than in the Spanish provinces. The associations in the Gallic and German provinces were a major factor in the integration of local elites and business men into the ‘New Roman Order’. They do not seem to have had this prime importance in the Spanish provinces
Grotta Romanelli (Southern Italy, Apulia). Legacies and issues in excavating a key site for the Pleistocene of the Mediterranean
Grotta Romanelli, located on the Adriatic coast of southern Apulia (Italy), is considered a key site for the Mediterranean Pleistocene for its archaeological and palaeontological contents. The site, discovered in 1874, was re-evaluated only in 1900, when P. E. Stasi realised that it contained the first evidence of the Palaeolithic in Italy. Starting in 1914, G. A. Blanc led a pioneering excavation campaign, for the first-time using scientific methods applied to systematic palaeontological and stratigraphical studies. Blanc proposed a stratigraphic framework for the cave. Different dating methods (C-14 and U/Th) were used to temporally constrain the deposits. The extensive studies of the cave and its contents were mostly published in journals with limited distribution and access, until the end of the 1970s, when the site became forgotten. In 2015, with the permission of the authorities, a new excavation campaign began, led by a team from Sapienza University of Rome in collaboration with IGAG CNR and other research institutions. The research team had to deal with the consequences of more than 40 years of inactivity in the field and the combined effect of erosion and legal, as well as illegal, excavations. In this paper, we provide a database of all the information published during the first 70 years of excavations and highlight the outstanding problems and contradictions between the chronological and geomorphological evidence, the features of the faunal assemblages and the limestone artefacts
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