news and events > talks

Talks, Seminars and Guest Lectures

CSCS Seminars -- Winter 2009

"Undoing evolution with the genetic code: experiments with a biological time machine"
Tuesday, April 21, 2009 note day of week
West Hall, Room 335
4:10p.m.

Professor Nigel Goldenfield
University of Illinois

Abstract:

Relics of early life, preceding even the last universal common ancestor of all life on Earth, are present in the structure of the modern day canonical genetic code. In this talk, I will draw attention to these relics, and discuss their interpretation from the perspective of the dynamical system that is evolution. I will argue that this viewpoint, and the quantitative, statistical dynamical calculations that it entails, suggest a natural scenario in which evolution exhibits three distinct dynamical regimes, differentiated respectively by the way in which information flow, genetic novelty and complexity emerge. Possible observational signatures of these predictions are discussed.

"Managing Business Complexity with Agent-Based Modeling and Simulation"
Thursday, February 5, 2009 note day of week
335 West Hall
4:00pm

Dr. Michael J. North
Deputy Director of the Center for Complex Adaptive Agent Systems Simulation

Abstract:

Agent-based modeling and simulation (ABMS) is a recent approach to modeling systems comprised of interacting autonomous agents. ABMS is already having far-reaching effects on the way that business and government use computers to support decision-making. Computational advances have made possible a growing number of agent-based applications in a variety of fields at ever-increasing scales. Applications range from using ABMS to model supply chains and logistics systems, to predicting the spread of epidemics and the diffusion of public information, from the identifying factors in the fall of ancient civilizations to understanding contemporary urban conflict, to name a few. This talk, based on North and Macal's new book Managing Business Complexity: Discovering Strategic Solutions with Agent-Based Modeling and Simulation (Oxford 2007), describes the foundations of ABMS, identifies software toolkits and methods, and approaches for developing agent models, from spreadsheets to enterprise-scale computer systems, and discusses the relationship between ABMS and traditional modeling techniques, emphasizing the value-added that ABMS provides, along with special challenges pertaining to data and model validation.

Bio:

Michael J. North, MBA, Ph.D. is the Deputy Director of the Center for Complex Adaptive Agent Systems Simulation within the Decision and Information Sciences Division of Argonne National Laboratory and is a Senior Fellow in the Joint Computation Institute of Argonne and the University of Chicago. Dr. North has over fifteen years of experience developing and applying advanced modeling and simulation applications for various branches of the U.S. federal government; state government; several international agencies; private industry; and academia. Dr. North is the lead author of the book Managing Business Complexity: Discovering Strategic Solutions with Agent-Based Modeling and Simulation (Oxford 2007) and has authored or co-authored over forty journal articles and conference papers. Dr. North has been recognized as a Senior Member by both the Association for Computing Machinery and the Institute of Electrical and Electronics Engineers. Dr. North holds ten college degrees, including a Ph.D. in Computer Science from the Illinois Institute of Technology.

"Complex Systems and Ecology & Evolutionary Biology"
Thursday, February 5, 2009 note day of week
1200 Chemistry Building
12:10pm

Dr. Pejman Rohani
Professor, University of Georgia: Odum School of Ecology

Abstract:

Understanding the transmission dynamics and persistence of avian influenza viruses (AIVs) in the wild is an important scientific and public health challenge because this system represents both a reservoir for recombination and a source of novel, potentially human-pathogenic strains. The current perspective locates all important transmission events on the nearly-direct fecal/oral bird-to-bird pathway. In this talk, I review overlooked evidence, based on which I propose that an environmental virus reservoir gives rise to indirect transmission. This transmission mode could play an important epidemiological role. Using a stochastic model, I will examine how neglecting environmentally generated transmission chains could underestimate the explosiveness and duration of AIV epidemics in addition to its long-term persistence. This phenomenon is shown to have potentially important disease control implications: the non-negligible probability of outbreak even when direct transmission is controlled, the long-term threat of previously infected sites, and the role of environmental heterogeneity in risk. Finally, I will speculate on the implications of environmental transmission for spread among networks of hosts, virus evolution and subtype diversity.

"The design of investments in biodiversity conservation"
Thursday, February 12, 2009 note day of week
Kraus Natural Science Auditorium
4:10-5:00p.m.

Dr. Paul Armsworth
Lecturer, The University of Sheffield, United Kingdom

Abstract:

Habitat destruction remains the primary threat to terrestrial biodiversity and direct, financial investment in habitat conservation efforts has become a cornerstone of the conservation movement. However, resources to support conservation efforts are limited and what funds are available need to be deployed as effectively as possible. I will examine conservation investment design as a case study in modeling coupled human and natural systems. I will consider how conservation agencies and NGOs should target land acquisition strategies as well as the effective design of incentive payment schemes that aim to encourage private landowners to provide conservation benefits on their properties. Drawing on examples from the US and the UK, I will show how a failure to study the natural environment as a coupled human and natural system has led to existing conservation programmes that are ineffective and risks conservation efforts backfiring and threatening more species than they save.

If you would like to meet with Dr. Armsworth, please contact his host, Dr. Mercedes Pascual

"High-Temperature Superconductivity: From Broken Symmetries to the Power Grid"
Tuesday, March 10, 2009 note day of week
340 West Hall
4:00p.m.
Refreshments before the talk

Dr. Laura H. Greene Professor, University of Illinois at Urbana-Champaign

Abstract:

Superconductivity, first discovered in 1911, is the loss of all electrical resistance by certain materials when cooled to very low temperature. In 1986, andmore recently in 2008, two new classes of superdonductors we call “high-temperature superconductors” were discovered which superconduct at much more easily obtainable temperatures. Each of these discoveries motivated an unprecedented world-wide flurry of research: Not only to the high-temperature superconductors represent facinating new classes of solid state of matter which break certain fundamental symmetries of Nature, but applications, such as impacting the power grid by significantly reducing power loss, are extremely promising.

Bio:

Laura H. Greene received her BS and MS degrees from The Ohio State University and in 1984, received a Ph.D. in Physics from Cornell University, investigating the linear and non-linear far-infrared properties of materials. She joined Bell Laboratories and then Bellcore, where she researched thin-film growth and tunneling of metallic multilayers, heavy- Fermions, superconductor-semiconductor hybrid structures and high-temperature superconductors. In 1992, she joined the senior physics faculty at the University of Illinois at Urbana-Champaign.

"Complex networks and the surveillance, dynamics, and evolution of infectious diseases"
Tuesday, March 10, 2009 note day of week
Lane Family Auditorium, Room 1690, SPH Tower
3:00p.m.

Dr. Erik Volz, PhD
Postdoctoral Fellow, Antiviral Research Center, University of California San Diego

Abstract:

Human populations are often organized in networks of spatially and temporally correlated relationships. In many areas of epidemiological research, it is important to account for network structure, such as when it affects the probability of being included in a sample of the probability of being infected in an epidemic. I will describe mathematical methods that account for network heterogeneities in survey statistics, mathematical epidemiology, and phylogenetics.First, I will review statistical tools to adjust for biases in chain-referal sampling methods that are widely used to monitor sexually transmitted infections. Such strategies are known to over-sample well-connected individuals, and assortativity induces a complex correlation-structure between sample units. Second, I will present a simple model based on ordinary differential equations that captures epidemiological dynamics in networks with complex and dynamic structures. This reveals a formal bridge between traditional mass action models and network models, and has yielded insights into the epidemiological consequences of serosorting and the efficacy of adaptive vaccination strategies. Finally, I will introduce a network-based coalescent theory for studying the impacts of epidemiological dynamics on viral evolution. Coalescents based on simple models of population growth can perform poorly for boom-and-bust epidemics, and correcting for network heterogeneities is essential for accurate estimation of coalescent rates.

"Dynamic Knowledge Representation with Agent-based Modeling:
Establishing a basis for an Evolutionary Paradigm for Biomedical Research"
Tuesday, April 7, 2009 note day of week
West Hall, Room 340
4:00p.m.

Gary An
Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL

Abstract:

Perhaps the greatest challenge facing the biomedical research community is the effective translation of basic mechanistic knowledge into the clinical arena. This challenge is most evident in attempts to understand, and more importantly, modulate "systems diseases" such as sepsis, cancer, autoimmune disorders and HIV. A key point in formulating an approach to these diseases is the recognition that the development of disease is a dynamic process. Methods of dynamic systems analysis can aid in the investigation of complex pathophysiological processes, and can augment existing discovery procedures in the biomedical arena. This approach is termed Dynamic Knowledge Representation and this talk will present a series of computational models of acute inflammation and sepsis demonstrating the use of Agent-based modeling towards this end. These models span a range of resolution from intracellular processes to simulated clinical trials, and can be integrated to reconstruct the multi-scale nature of biological systems. Finally, a general agent-based format for dynamic knowledge representation is presented as a means of augmenting the ability of researchers to "check" their mental models, share their expertise in a community-wide knowledge landscape, and move towards a research "ecosystem" for the advancement of scientific knowledge.

"Social Systems as (not only) Complex Interactive Networks"
Tuesday, April 14, 2009 note day of week
West Hall, Room 340
4:00p.m.

Péter Érdi
Henry Luce Professor

Abstract:

The place of network models in social dynamics is studied. Social networks can be derived as the discrete, somewhat more microscopic, approaches to continuous models; the nodes might be people, organizations, communities, documents, etc. Dynamic network models have two extreme forms: (i) propagation on netowrks, (ii) evolution of netowrks. This latter case is discussed in a more detailed way. The inverse (date-drive) problem starts from a network assembled from experimental data and the kernel-based measurement algorithm serves a possible kernel function. Stochastic kinetic modeling of the US patents citation network is presented. Data on more than two million patents and their citations served as the experimental basis of our analysis. some possible implications of our results for patent policy is discussed. (Collaboration with Gabor Csardi, Katherine Strandburg and Jan Tobochnik.)

Bio:
Peter Erdi is a Henry Luce Professor, the director of the Center for Complex System Studies at Kalamazoo College and the head of the Dept. Biophysics, KFKI Research Institute for Particle and Nuclear Physics of the Hungarian Academy of Science, Budapest. Major books: Mathematical Models of Chemical Reactions: Theory and Applications of Deterministic and Stochastic Models. Princeton University Press (with J. Toth); Neural Organization: Structure, Function, and Dynamics. The MIT Press (with M Arbib and J. Szentagothai), Complexity Explained, Springer.