Chattering and singular perturbation in discontinuous dynamics

Download
2017
Çağ, Sabahattin
The main purpose of this dissertation is to address the chattering and singularity phenomena in discontinuous dynamical systems. The study describes models of singular impulsive differential equations such that in the system, not only the differential equation is singularly perturbed, but also the impulsive function is singular. Tikhonov Theorem is extended for the impulsive differential equations. Interestingly, in some models described here, a solution of the problem approaches more than one root of the differential equation as the parameter decreases to zero. Wilson-Cowan neuron model is studied with impulse function in which the membrane time constant is considered as both the singularity and bifurcation parameter. A new technique of analysis of the phenomenon is suggested. This allows to consider the existence of solutions of the model and bifurcation in ultimate neural behavior is observed through numerical simulations. The bifurcations are reasoned by impulses and singularity in the model and they concern the structure of attractors, which consist of newly introduced sets in the phase space such that medusas and rings. Moreover, the singular impact moments are introduced and they are utilized for the problems with chattering solutions. The singular impulse moments gives the advantages that the chattering arising in models, e.g., a bouncing ball, an inverted pendulum and a hydraulic relief valve, can be analyzed through the singularity point of view. The presence of chattering is shown exclusively by examination of the right hand side of impact models. Criteria for the sets of initial data which always lead to chattering are established. 

Suggestions

Chattering as a singular problem
Akhmet, Marat (2017-12-01)
This paper presents the chattering through the singularity point of view for the first time. The main novelty of this article is that impact moments are considered as a singularity phenomenon. A bouncing ball, an inverted pendulum and a hydraulic relief valve models are considered for the study. Moreover, the behavior of solutions of a spring-mass system is studied for the small mass. Simulations are given to support the theoretical analysis.
Model theory of derivation spaces
Kasal, Özcan; Pierce, David; Department of Mathematics (2010)
In this thesis, the notion of the derivation spaces is introduced. In a suitable two-sorted language, the first order theory of these structures is studied. In particular, it is shown that the theory is not companionable. In the last section, the language is expanded by predicate symbols for a dependence relation. In this language it is shown that the extension of the corresponding theory has a model companion. It is shown that the model companion is a complete, unstable theory which does not eliminate quan...
Maximally Permissive Hierarchical Control of Decentralized Discrete Event Systems
SCHMİDT, KLAUS WERNER; Schmidt, Klaus Verner (2011-04-01)
The subject of this paper is the synthesis of natural projections that serve as nonblocking and maximally permissive abstractions for the hierarchical and decentralized control of large-scale discrete event systems. To this end, existing concepts for nonblocking abstractions such as natural observers and marked string accepting (msa)-observers are extended by local control consistency (LCC) as a novel sufficient condition for maximal permissiveness. Furthermore, it is shown that, similar to the natural obse...
Linearization in stability in gravity theories
Altaş Kiracı, Emel; Tekin, Bayram; Department of Physics (2018)
In a nonlinear theory, such as gravity, physically relevant solutions are usually hard to find. Therefore, starting from a background exact solution with symmetries, one uses the perturbation theory, which albeit approximately, provides a lot of information regarding a physical solution. But even this approximate information comes with a price: the basic premise of a perturbative solution is that it should be improvable. Namely, by going to higher order perturbation theory, one should be able to improve and ...
Application of the boundary element method to parabolic type equations
Bozkaya, Nuray; Tezer-Sezgin, Münevver; Department of Mathematics (2010)
In this thesis, the two-dimensional initial and boundary value problems governed by unsteady partial differential equations are solved by making use of boundary element techniques. The boundary element method (BEM) with time-dependent fundamental solution is presented as an efficient procedure for the solution of diffusion, wave and convection-diffusion equations. It interpenetrates the equations in such a way that the boundary solution is advanced to all time levels, simultaneously. The solution at a requi...
Citation Formats
S. Çağ, “Chattering and singular perturbation in discontinuous dynamics,” Ph.D. - Doctoral Program, Middle East Technical University, 2017.