Abstract

Patterns of connectivity (structure) have been amply studied in network science and patterns of dynamics have been studied in dynamical systems theory. Still, much remains to be done to characterize redundancy and its importance for understanding and controlling the dynamics of complex systems---which, ultimately, defines their function. In this talk we will present our recent studies of redundancy in both the structure and dynamics of complex systems. The first concept we present is the invariant sub-graph that is revealed by the computation of all shortest paths (metric closure) of a weighted graph. We refer to this subgraph as the metric backbone of a complex network.  The size of the backbone subgraph, in relation to the size of the original graph, defines the amount of redundancy in the network: edges not on this backbone are superfluous in the computation of shortest paths.  We demonstrate the utility of the metric backbone with an analysis of social contact networks (via wearable sensors) used in epidemic spread models, as well as on other technological, brain, and gene regulation networks.  The second concept stems from a dynamics perspective. We show that the control of complex networks crucially depends on redundancy that exists at the level of variable dynamics. To understand how control and information effectively propagate in such complex systems, we propose the effective graph which results after computation of effective connectivity in a discrete multivariate dynamical system.  Finally, we discuss how we are demonstrating the utility of the approach with the analysis of a battery 50+ systems biology automata networks, including systems biology models of cancer.

Biography

Luis M. Rocha is Professor of Informatics in the School of Informatics, Computing, and Engineering, at Indiana University, Bloomington, where he is director of the NSF-NRT Interdisciplinary Training Program in Complex Networks and Systems director of the Complex Networks and Systems track of the Informatics PhD Program, member of the advisory council of the Indiana University Network Science Institute, and core faculty of the Cognitive Science Program. Dr. Rocha is a Fulbright Scholar and is Principal Investigator at the Instituto Gulbenkian da Ciencia, Portugal, and has been a Visiting Professor of the Neuroscience Program, at the Champalimaud Foundation in Portugal, and the Center for Theoretical Physics at the Aix-Marseille University, France. His research is on complex networks & systems, computational & systems biology, and computational intelligence. He received his Ph.D in Systems Science in 1997 from the State University of New York at Binghamton. From 1998 to 2004 he was a permanent staff scientist at the Los Alamos National Laboratory, where he founded and led a Complex Systems Modeling Team during 1998-2002, and was part of the Santa Fe Institute research community. He has organized major conferences in the field such as the Tenth International Conference on the Simulation and Synthesis of Living Systems (Alife X) and the Ninth European Conference on Artificial Life (ECAL 2007). He has published many articles in scientific and technology journals, and has been the recipient of several scholarships and awards. At Indiana University, he has received the Indiana University, School of Informatics & Computing, Trustees Award for Teaching Excellence in 2006 and 2015 after developing the complex systems training program and syllabi for several courses.

CNS-NRT Student Discussion Seminar

• Lead: Rion Brattig Correia
• Date/Time: November 26th, 2018 at 3pm
• Location: Conference Room, CNS-NRT shared space.

Papers to be discussed

• A. Gates and L.M. Rocha. [2016] "Control of complex networks requires both structure and dynamics." Scientific Reports 6, 24456. doi: 10.1038/srep24456.