Speaker
Ginestra Bianconi

Description A large variety of complex systems, from the brain to the weather networks and complex infrastructures, are formed by several networks that coexist, interact and coevolve forming a “network of networks”. Modeling such multilayer structures and characterizing the rich interplay between their structure and their dynamical behavior is crucial in order to understand and predict complex phenomena. In this talk I will present recent works on statistical mechanics of multiplex networks. Multiplex networks are formed by N nodes linked in different layers by different networks. I will present models that generate multiplexes with different types of correlations between the layers, and characterize new percolation phenomena on multiplex networks, showing first order phase transitions, bistability or a complex phase diagram with tricriticals points and higher order critical points.

Speaker
Ulrich Parlitz

Description Prediction and analysis of complex dynamics requires a suitable representation of the underlying dynamical structure in terms of a mathematical model (ODE, PDE, ..) and methods for estimating relevant model parameters and the current state of the system. Whether this task can be solved depends on the observability of the required quantities given the available (time series) data and the efficacy of the estimation algorithm chosen. We shall present methods to address the observability problem and algorithms for parameter and state estimation employing nonlinear optimization and synchronization.

Speaker
Oleguer Sagarra

Description THIS SEMINAR HAS BEEN CANCELLED! In this talk I will justify the need for big (analytical) models in the era of big data. Using a particular example on human mobility records, I will introduce some basic concepts about the use of maximum entropy models as null proxies to assess relevant features observed in big datasets susceptible to be represented as complex networks. In particular, a quick review over the theory of ensembles applied to networks covering the three fundamental collectivities (micro-canonical, canonical and grand-canonical) will be performed. Hence, I will try to introduce from a "modern" viewpoint the tools laid by Gibbs in the XIXth century and show that they can be very useful to address XXIth century problems.

Speaker
Albert Diaz-Guilera

Description La complexitat s'estén a través de múltiples escales, que van des de l’àtom a les galàxies, i que formen geometries intricades. El comportament complex emergent pot tenir diferents orígens, però avui dia és clar que més enllà de les interaccions no lineals entre unitats, la topologia de les interaccions exerceix un paper fonamental a totes les escales. D'altra banda, les xarxes a diferents nivells estan interactuant. En aquesta xerrada revisarem els diferents nivells de descripció dels sistemes vius en què ens trobem amb xarxes complexes i mostrarem com sorgeixen en diferents escales i com interactuen. Això va des de l'escala cel·lular mitjançant xarxes metabòliques o xarxes de regulació gènica a les xarxes dels individus a nivell mundial, com Facebook o Twitter, en la societat de les tecnologies de la informació i la comunicació, o les xarxes d'interacció d'espècies en ecosistemes complexos.

Speaker
Mario Chavez