Month: August 2022

Network structural origin of instabilities in large complex systems

CHAO DUAN, TAKASHI NISHIKAWA, DENIZ EROGLU, AND ADILSON E. MOTTER 
SCIENCE ADVANCES 15 Jul 2022 Vol 8, Issue 28

A central issue in the study of large complex network systems, such as power grids, financial networks, and ecological systems, is to understand their response to dynamical perturbations. Recent studies recognize that many real networks show nonnormality and that nonnormality can give rise to reactivity—the capacity of a linearly stable system to amplify its response to perturbations, oftentimes exciting nonlinear instabilities. Here, we identify network structural properties underlying the pervasiveness of nonnormality and reactivity in real directed networks, which we establish using the most extensive dataset of such networks studied in this context to date. The identified properties are imbalances between incoming and outgoing network links and paths at each node. On the basis of this characterization, we develop a theory that quantitatively predicts nonnormality and reactivity and explains the observed pervasiveness. We suggest that these results can be used to design, upgrade, control, and manage networks to avoid or promote network instabilities.

Read the full article at: www.science.org

The effect of co-location on human communication networks

Daniel Carmody, Martina Mazzarello, Paolo Santi, Trevor Harris, Sune Lehmann, Timur Abbiasov, Robin Dunbar & Carlo Ratti
Nature Computational Science volume 2, pages494–503 (2022)

The ability to rewire ties in communication networks is vital for large-scale human cooperation and the spread of new ideas. We show that lack of researcher co-location during the COVID-19 lockdown caused the loss of more than 4,800 weak ties—ties between distant parts of the social system that enable the flow of novel information—over 18 months in the email network of a large North American university. Furthermore, we find that the reintroduction of partial co-location through a hybrid work mode led to a partial regeneration of weak ties. We quantify the effect of co-location in forming ties through a model based on physical proximity, which is able to reproduce all empirical observations. Results indicate that employees who are not co-located are less likely to form ties, weakening the spread of information in the workplace. Such findings could contribute to a better understanding of the spatiotemporal dynamics of human communication networks and help organizations that are moving towards the implementation of hybrid work policies to evaluate the minimum amount of in-person interaction necessary for a productive work environment.

Read the full article at: www.nature.com

Esteban Moro – Collaborating with the Competition

Esteban’s work lies in the intersection of big data and computational social science, with special attention to human dynamics, collective intelligence, social networks and urban mobility in problems like viral marketing, natural disaster management, or economical segregation in cities.

Esteban is creative and exploring in his work, and has made important contributions in a number of topics, especially recently using massive datasets to understand problems like how humans communicate, how to political opinion spreads in social networks or building alternative wellbeing indexes.

In our conversation, we talk about his career, his science, and go deep with his 2011 paper “Dynamical strength of social ties in information spreading”, which is not only an interesting paper … but also comes with a very nice story of how we can build communities in science by collaborating even between competing groups.

Listen at: toolazy.buzzsprout.com