Date: Tuesday, 14 May 2019, at 18:00
Venue: Aula 2 (Physics), Faculty of Sciences (Building A), University of Zaragoza. Spain.
Speaker: Carlos Gracia
Title:
Trading in Complex Networks.
Abstract:
Global supply networks in agriculture, manufacturing, and services are a defining feature of the modern world. The efficiency and the distribution of surpluses across different parts of these networks depend on choices of intermediaries. This paper conducts price formation experiments with human subjects located in large complex networks to develop a better understanding of the principles governing behavior. Our first finding is that prices are larger and trade significantly less efficient in small-world networks as compared to random networks. Our second finding is that location within a network is not an important determinant of pricing. An examination of the price dynamics suggests that traders on cheapest – and hence active -
paths raise prices while those off these paths lower them. We construct an agent-based model (ABM) that embodies this rule of thumb. Simulations of this ABM yield macroscopic patterns consistent with the experimental patterns. Finally, we extrapolate the ABM on to significantly larger random and small-world networks and find that network topology remains a key determinant of pricing and efficiency.
Date: Tuesday, April 2, 2019, at 18:00
Venue: Aula 2 (Physics), Faculty of Sciences (Building A), University of Zaragoza. Spain.
Speaker: Dan Lu
Title:
“Norm violation” behaviour: modelling the social dynamics of Corruption.
Abstract:
The existence of social norms whose violation is socially agreed to deserve some punishment, is perhaps one of the most widespread features across the history of human cultures and societies. A ubiquitous type of social-norm violating behavior is corruption. In this talk, I will introduce a compartmental, 3-state population flow model of corruption. I will start from the assumptions of the model and how we formulate it. After developing its mean field theory, I will analyse the observable macroscopic states of the population dynamics in detail.
Date: Tuesday, March 12, 2019, at 18:00
Venue: Aula 2 (Physics), Faculty of Sciences (Building A), University of Zaragoza. Spain.
Speaker: Clàudia Payrató
Title:
Mutualistic networks: Emergence of structural patterns and dynamic implications of introducing temporal variability.
Abstract:
Mutualistic networks are characterized by the fact that its components interact through mutually benefiting activities. This network representation has been of particular importance in ecology, where it served to model large mutualistic communities formed, for instance, by plants and their pollinators or by plants and seed-disperser birds. In this talk, I will explore two research questions concerning ecological mutualistic networks. In the first place, how do their structural characteristics appear? And, secondly, does temporal turnover of species significantly affect population dynamics?
I will start by describing how, using a statistical physics approach, we have recently shown that the vastly widespread property called nestedness is actually determined by local traits, particularly the degree sequences. Secondly, I will address the consequences for biodiversity persistence of introducing empirical information about the temporal patterns of activity of plants and pollinators. To do so, I will use a multilayer network framework which incorporates both mutualistic and competitive interactions.
On Tuesday, February 19, 2019, at 18:00 David Soriano will give a talk titled “Effects of recurrent human mobility on epidemic spreading and social segregation in Colombian cities.”
Venue: Chemistry meeting room, Faculty of Sciences, University of Zaragoza. Spain.
