Events

We plan to have two types of events. 


The zoom seminar will start in January 2023. Please sign up to our mailing list or send us an email to receive the link.

Zoom Seminar Schedule:


The term 2, 23/24 seminars are:


Title: A kinetic and mean-field perspective on metaheuristic optimization


Abstact: Metaheuristic optimization based on multi-agent dynamics has a long history and plays a pivotal role today in many applications, ranging from machine learning to optimal control. In this talk, we will show how the use of kinetic and mean-field techniques enables a rigorous mathematical formulation of such algorithms and permits to prove convergence to the global minimum under mild assumptions on the objective function. In particular, we will focus on analyzing some of the most popular algorithms, such as simulated annealing, genetic algorithms and particle swarm optimization.26

Past seminars:


Speaker Michele Coti Zelati

Title: Orientation mixing in active suspensions


Abstract:


We study a popular kinetic model introduced by Saintillan and Shelley for the dynamics of suspensions of active elongated

particles. We focus on the linear analysis of incoherence, that is on the linearized equation around the uniform distribution, in the

regime of parameters corresponding to spectral (neutral) stability. We show that in the absence of rotational diffusion, the

suspension experiences a mixing phenomenon similar to Landau damping. We show that this phenomenon persists for small rotational

diffusion, and is combined with an enhanced dissipation at time scale at a faster time scale than the diffusive one.



 Speaker Michela Ottobre 

Title: Non mean-field Vicsek type models for collective behaviour 

Abstract: We consider  Interacting Particle dynamics with Vicsek type interactions, and their macropscopic PDE limit,  in the non-mean-field regime; that is, we consider the case in which each  particle/agent in the system interacts only with a prescribed subset of the particles in the system (for example, those within a certain distance).  It was observed by Motsch and Tadmore that in this non-mean-field regime the  influence between agents (i.e. the interaction term) can be scaled either by the total number of agents in the system (global scaling) or by the number of agents with which the particle is effectively interacting  at time t  (local scaling). We compare the behaviour of the globally scaled and the locally scaled system in many respects; in particular we observe that, while both models exhibit multiple stationary states,  such equilibria are unstable (for certain parameter regimes) for the globally scaled model, with the instability leading to travelling wave solutions,  while they are always stable for the locally scaled one.   

Based on  work with with P. Butta', B. Goddard, T. Hodgson, K.Painter.  


Speaker: Florian Theil

Title: Justification of kinetic equations

Abstract: We give an overview of past and current efforts to provide mathematically rigorous derivations of kinetic equations from particle systems. The main goal is to explain the conceptual challenges.