Plenary speakers at CASSC 2020

  • István Kovács, Department of Physics and Astronomy , Northwestern University Kovács Lab

Dr. István Kovács is an Assistant Professor in the Department of Physics and Astronomy at Northwestern University. He earned his Ph.D. in 2013 from the Eötvös Loránd University in Budapest, Hungary, working on disordered quantum systems and infection spreading. Before joining Northwestern, he was a postdoctoral researcher at the Network Science Institute of Northeastern University and at the Center for Cancer Systems Biology of Dana-Farber Cancer Institute. His group is developing novel methodologies to predict the emerging structural and functional patterns in a broad spectrum of problems ranging from systems biology to quantum physics, in close collaboration with experimental groups.

Abstract: Utilizing networks with error bars

Network theory is a powerful tool to describe and study complex systems, and there has been tremendous progress in mapping large networks in all areas of science, leading to a growing library of complex network datasets. It is, however, unrealistic to assume that the obtained graphs are exact. Inherent limitations of the measurement processes lead to errors, biases and missing data. Therefore, as in any other quantitative field, it would be of paramount importance to characterize the uncertainty of our data. Yet, unlike a simple error bar for a single-valued quantity, the uncertainty of a network structure itself is expected to have a complex, network structure, requiring novel methodologies. Currently, there are only a few cases where we have uncharted not only the expected graph structure but also a full quantification of the error and incompleteness patterns. On the example of the yeast genetic interaction network, we will overview how such detailed information can help us to solve key problems, such as link prediction, noise reduction, community detection, stability analyses or functional annotation. To conclude, putting error bars on our network maps is not a nuisance but an essential ingredient in addressing long-standing problems in the field.

  • Petia M. Vlahovska, Department of Engineering Sciences and Applied Mathematics, Northwestern University Vlahovska Group

Petia M. Vlahovska received a Ph.D. in chemical engineering from Yale (2003) and MS in chemistry from Sofia University, Bulgaria (1994). She was a postdoctoral fellow in the Membrane Biophysics Lab at the Max Planck Institute of Colloids and Interfaces. She spent ten years on the faculty at Dartmouth College and Brown University, before joining the faculty at Northwestern University in 2017. Her research interests are in fluid dynamics, membrane biophysics, and soft matter. Dr. Vlahovska is the recipient of the NSF Career Award, the David Crighton Fellowship from DAMPT, University of Cambridge (UK), and a Humboldt Fellowship.

Abstract: Emergent dynamics in collectives of active colloids

Flocks of birds and schools of fish are familiar examples of emergent collective behavior, where interactions between self-propelled (active) individuals lead to coherent motion on a scale much larger than the isolated unit. Similar phenomena have been observed with active micro-particles such as bacteria and motile colloids. Recently, the Quincke instability (spontaneous spinning of a dielectric particle in an applied uniform DC field) has attracted great interest as a means of propelling colloids, by simply letting the particles roll on a surface. In this talk, I will present our work on how Quincke rollers, previously studied mainly as active Brownian particles, can be designed to perform Run-and-Tumble-like locomotion mimicking bacteria such as E. coli. Populations of the Quincke random walkers self-organize and exhibit behaviors reminiscent of bacterial suspensions such as dynamic clusters and mesoscale turbulent-like flows.

  • Ian Tobasco, Department of Mathematics, Statistics, and Computer Science, University of Illinois at Chicago Ian’s Homepage

Ian Tobasco is an Assistant Professor at the University of Illinois Department of Mathematics, Statistics, and Computer Science. He holds a Ph.D. in Mathematics from the Courant Institute of Mathematical Sciences at New York University, and a B.S.E. in Aerospace Engineering from the University of Michigan.

Ian’s research focuses on the Calculus of Variations and Nonlinear Partial Differential Equations. He enjoys problems that sit at the interface of mathematics, physics, and engineering, where advances in pure mathematical analysis can lead to scientific breakthroughs in the lab and vice versa. Ian’s recent work involves the use of energy minimization to explain and classify the zoo of wrinkling, crumpling, and folding patterns exhibited by thin elastic sheets. Other interests include the design of optimal transport mechanisms in fluid dynamics and their comparison with naturally occurring turbulent transport, as well as the variational analysis of spin glasses.

Abstract: Wrinkles, Crumples, and Origami: The Mathematics and Physics of Thin Elastic Sheets

The world is full of patterns forming thin elastic sheets, from organic ones like leaves and flowers to inorganic membranes manufactured in the lab. What are the limits of such biologically-inspired designs? After introducing the basic mathematics and physics involved, this talk will focus on the case of designing wrinkle patterns by the use of geometric incompatibilities, such as occurs when a sphere or saddle surface is forced to become flat. This basic sounding setup leads to surprisingly rich pattern morphologies, which exhibit a mixed ordered-disordered response with wrinkles depending strongly on the shell’s initial shape. Mathematical analysis of appropriate non-convex energy in the vanishing thickness limit yields several simple yet far-reaching geometric principles explaining the patterns that form. These include, for instance, a classification of the local geometry of ordered wrinkles into three basic types, as well as a Fermat-like principle predicting their global arrangement in negatively-curved shells. Such rules open the way towards the principled design of wrinkle patterns, with potential applications ranging from flexible electronics to synthetic skins.

  • Mustafa Bilgic, Department of Computer Science, Illinois Institute of Technology Mustafa’s Homepage