2,014 research outputs found
Stability Criteria for SIS Epidemiological Models under Switching Policies
We study the spread of disease in an SIS model. The model considered is a
time-varying, switched model, in which the parameters of the SIS model are
subject to abrupt change. We show that the joint spectral radius can be used as
a threshold parameter for this model in the spirit of the basic reproduction
number for time-invariant models. We also present conditions for persistence
and the existence of periodic orbits for the switched model and results for a
stochastic switched model
Robust synchronization of heterogeneous robot swarms on the sphere
Synchronization on the sphere is important to certain control applications in
swarm robotics. Of recent interest is the Lohe model, which generalizes the
Kuramoto model from the circle to the sphere. The Lohe model is mainly studied
in mathematical physics as a toy model of quantum synchronization. The model
makes few assumptions, wherefore it is well-suited to represent a swarm.
Previous work on this model has focused on the cases of complete and acyclic
networks or the homogeneous case where all oscillator frequencies are equal.
This paper concerns the case of heterogeneous oscillators connected by a
non-trivial network. We show that any undesired equilibrium is exponentially
unstable if the frequencies satisfy a given bound. This property can also be
interpreted as a robustness result for small model perturbations of the
homogeneous case with zero frequencies. As such, the Lohe model is a good
choice for control applications in swarm robotics
Spectral control for ecological stability
A system made up of N interacting species is considered. Self-reaction terms
are assumed of the logistic type. Pairwise interactions take place among
species according to different modalities, thus yielding a complex asymmetric
disordered graph. A mathematical procedure is introduced and tested to
stabilise the ecosystem via an {\it ad hoc} rewiring of the underlying
couplings. The method implements minimal modifications to the spectrum of the
Jacobian matrix which sets the stability of the fixed point and traces these
changes back to species-species interactions. Resilience of the equilibrium
state appear to be favoured by predator-prey interactions
An Overview of Recent Progress in the Study of Distributed Multi-agent Coordination
This article reviews some main results and progress in distributed
multi-agent coordination, focusing on papers published in major control systems
and robotics journals since 2006. Distributed coordination of multiple
vehicles, including unmanned aerial vehicles, unmanned ground vehicles and
unmanned underwater vehicles, has been a very active research subject studied
extensively by the systems and control community. The recent results in this
area are categorized into several directions, such as consensus, formation
control, optimization, task assignment, and estimation. After the review, a
short discussion section is included to summarize the existing research and to
propose several promising research directions along with some open problems
that are deemed important for further investigations
Self-Evaluation Applied Mathematics 2003-2008 University of Twente
This report contains the self-study for the research assessment of the Department of Applied Mathematics (AM) of the Faculty of Electrical Engineering, Mathematics and Computer Science (EEMCS) at the University of Twente (UT). The report provides the information for the Research Assessment Committee for Applied Mathematics, dealing with mathematical sciences at the three universities of technology in the Netherlands. It describes the state of affairs pertaining to the period 1 January 2003 to 31 December 2008
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