Network Frontier Workshop Highlighting leading-edge research on complex networks Program December 1 – 2, 2011 Sponsored by Northwestern Institute on Complex Systems Northwestern University Weinberg College of Arts and Sciences Chambers Hall 600 Foster Street Organized by The Motter Group Evanston, IL 60208 Scientific organizer: Jie (Rio) Sun USA Administrative organizer: Luciana Zanella Schedule Thursday, December 1st 8:15 – 8:30 Registration Ian Dobson (Iowa State University) 8:30 – 9:15 Estimating Propagation and the Statistics of Blackout Extent from Electric Power Grid Cascading Failure Data Raissa D’Souza (University of California, Davis) 9:15 – 9:40 Percolation and Cascades in Interdependent Networks Tom Hurd (McMaster University) 9:40 – 9:55 Analyzing Contagion in Banking Networks Simone Lenzu (Northwestern University) 9:55 – 10:10 Liquidity Shocks in Different Interbank Network Topologies 10:10 – 10:40 Coffee Break Kevin M. Lynch (Northwestern University) 10:40 – 11:25 Compiling Global Behaviors into Local Controllers for Mobile Sensor Networks Rachel Leander (The Ohio State University) 11:25 – 11:50 Using Optimal Control Theory to Identify Network Structures that Foster Synchrony Artemy Kolchinsky (Indiana University, Bloomington) 11:50 – 12:05 Prediction and Modularity in Dynamical Systems Igor Belykh (Georgia State University) 12:05 – 12:30 Synchronization in Networks with Mixed Graphs 12:30 – 2:15 Lunch Break (Allen Center) Adilson E. Motter and Sean P. Cornelius (Northwestern University) 2:15 – 3:00 Control of Complex Networks with Compensatory Perturbations Zachary G. Nicolaou (California Institute of Technology) 3:00 – 3:25 Explicit Negative Compressibility Materials via Network Destabilization Christian Darabos (Dartmouth College) 3:25 – 3:40 The Influence of Whole Genome Duplication and Subsequent Diversification on Environmental Robustness and Evolutionary Innovation in Gene Regulatory Networks Maxim N. Artyomov (Broad Institute of MIT and Harvard) 3:40 – 3:55 Systematic Identification of Topologically Essential Interactions in Regulatory Networks 3:55 – 4:25 Coffee Break Marty Golubitsky (The Ohio State University) 4:25 – 5:10 Patterns of Phase-Shift Synchrony Joel Nishimura (Cornell University) 5:10 – 5:25 Robust Convergence of Pulse-Coupled Oscillators on Networks with Delays Per Sebastian Skardal (University of Colorado, Boulder) 5:25 – 5:40 Hierarchical Synchrony of Phase Oscillators in Modular Networks Takashi Nishikawa (Clarkson University) 5:40 – 6:05 Discovering Network Structure Beyond Communities 6:05 – 7:30 Wine and Cheese Dirk Brockmann (Northwestern University) 6:25 – 7:00 "Feel Sick? Follow the Money!" - A Network Perspective on Human Mobility and Global Disease Dynamics Friday, December 2nd Peter Grassberger (University of Calgary) 8:20 – 9:05 Percolations Galore Erik M. Bollt (Clarkson University) 9:05 – 9:30 Synchronization as a Process of Sharing and Transferring Information PJ Lamberson (Northwestern University) 9:30 – 9:45 Network Games with Local Correlation and Clustering James P. Bagrow (Northwestern University) 9:45 – 10:00 Structural and Social Aspects of Human Mobility 10:00 – 10:30 Coffee Break Daniel ben-Avraham (Clarkson University) 10:30 – 11:15 Geography and Complex Networks Juan G. Restrepo (University of Colorado, Boulder) 11:15 – 11:40 Criticality and Statistics of Avalanches in Network Cascading Processes Lynne Kiesling (Northwestern University) 11:40 – 12:05 Economic Regulation, Transactive Technology, and Knowledge in Retail Electricity Markets Jie (Rio) Sun (Northwestern University) 12:05 – 12:30 Identification of Interventions to Control Network Crises 12:30 – 2:15 Lunch Break (Allen Center) Yong-Yeol Ahn (Indiana University, Bloomington) 2:15 – 2:30 Flavor Network and the Principles of Food Paring Joo Sang Lee (Northwestern University) 2:30 – 2:45 Network Model Explains why Cancer Cells Use Inefficient Pathway to Produce Energy Edward Ott (University of Maryland, College Park) 2:45 – 3:30 Orbital Stability of Dynamics on Gene Networks 3:30 – 6:00 Physics & Astronomy Colloquium (Tech L211) 3:30 – 4:00 Refreshments Réka Albert (Pennsylvania State University) 4:00 – 5:00 Linking the Structure and Dynamics of Biological Regulatory Networks 5:00 – 6:00 Reception Session Chairs December 1, Morning Jie (Rio) Sun December 2, Morning Michael Schnabel December 1, Afternoon Thomas Wytock December 2, Afternoon Takashi Nishikawa December 2, Colloquium Adilson E. Motter Abstracts – Keynote Presentations the system in many other situations (social networks, Réka Albert networks of flight connection, neuron network of the brain, etc.). This problem, known as the “geography” of complex networks, has received surprisingly little Professor attention, and constitutes at present one of the most Physics & Biology promising avenues for fruitful research in the area of Pennsylvania State University complex networks. In this talk, I shall discuss some of the basic existing findings about the structure of geographically embedded scale-free networks, and how to navigate geographical networks by decentralized Linking the Structure and Dynamics of Biological (local) algorithms, and will point at some of the vast areas Regulatory Networks (Dec 2, 4:00pm) left wide open to exploration. Interaction between gene products forms the basis of essential biological processes like signal transduction, cell metabolism or embryonic development. Recent experimental advances helped uncover the structure of Ian Dobson many molecular-to-cellular level networks, creating a surge of interest in the dynamical description of these Sandbulte Professor processes. Differential equation based modeling Electrical & Computer Engineering frameworks are greatly hampered by the sparsity of known kinetic detail. As an alternative, qualitative models Iowa State University assuming a small set of discrete states for gene products are gaining acceptance. Many results also suggest that the interaction topology plays a determining role in the Estimating Propagation and the Statistics of Blackout dynamics of regulatory networks. In this presentation I Extent from Electric Power Grid Cascading Failure Data will explore discrete modeling in several contexts: as the (Dec 1, 8:30am) basis of successful predictive models of signal transduction and immune responses, as a tool for Large blackouts often involve the cascading failure of inferring regulatory mechanisms, and as a key step in transmission lines. We estimate how line outages connecting signaling network structure and dynamics. propagate from observed data, and obtain a branching process probabilistic model of the cascading line outages. Then, given assumed or estimated initial line outages, we can calculate the probability distribution of the extent of the cascading outage. This gives a way to extend risk Daniel ben-Avraham analysis from the analysis of initial failures to also include the effect of cascading. The bulk statistical approach Professor opens opportunities for monitoring the cascading risk Physics from about one year of standard utility data. We will also Clarkson University make some general remarks about how bulk statistical approaches arise for blackouts and how modeling approaches can fail or be justified. Geography and Complex Networks (Dec 2, 10:30am) The actual placing of the nodes of complex networks in space, while optional, or non-applicable in many cases (e.g., citation networks, proteomics and metabolism networks, etc.) is highly relevant and an important part of finite size scaling. Finally, I will present “agglomerative percolation” (AP), a model originally introduced to Marty Golubitsky understand the claim that network renormalization can demonstrate the fractality of some small world networks. Distinguished Professor of The most exotic feature of AP is that it leads to different Mathematics & Physical Sciences scaling behavior on square and triangular 2-d lattices, in The Ohio State University flagrant violations of universality. Patterns of Phase-Shift Synchrony (Dec 1, 4:25pm) This talk discusses a result (joint with David Romano and Yunjiao Wang) that classifies rigid patterns of phase-shift Kevin M. Lynch synchrony in time-periodic solutions to general network systems. Professor Mechanical Engineering Northwestern University Peter Grassberger Compiling Global Behaviors into Local Controllers for Mobile Sensor Networks (Dec 1, 10:40am) Visiting iCORE Research Professor Mobile sensor networks can be deployed for tasks such Physics & Astronomy as environmental monitoring. Decentralized control University of Calgary algorithms allow the mobile sensors to adapt to a changing environment and to failure of individual sensors, without the need for a centralized controller. Percolations Galore (Dec 2, 8:20am) I will describe the control theory and experimental testbed we are developing to support “swarms” of Although percolation theory was considered a mature mobile sensors. This work is based on the concept of subject several years ago, recent progress has changed “information diffusion” in ad hoc communication this radically. While “classical” or “ordinary” percolation networks and motion control laws that drive the sensors (OP) is a second order phase transition between long to optimally acquire information. This work is joint with range connectivity and disconnectedness on diluted Prof. Randy Freeman (Northwestern University) and the regular lattices or random graphs, examples have now Naval Research Lab. been found where this transition can