Between Nature and Science:
Advanced Modeling Concepts For Environmental Science
Special Colloquium Series, Spring & Fall 2005
The complexity of natural systems has challenged scientists to seek new approaches to better describe, understand, and analyze environmental processes. Conceptual frameworks are sought that appropriately account for the effects of heterogeneity, patterns, hierarchies, and other complex interactions in natural systems at multiple space and time scales. Recent advances in physics and applied mathematics have led to the development of fascinating new methods that may serve this purpose in many environmental science disciplines.
This colloquium series features internationally acclaimed scientists that work at the leading edge of developing nontraditional mathematical, physical, and chemical concepts applicable to complex systems. These concepts include scaling, percolation theory, novel stochastic methods, fractals, chance, networks, cellular automata, and other aspects of nonlinear dynamical systems.
Many of these concepts are absent from the conventional palette of environmental scientists and of students in environmental sciences and geosciences. The specific purpose of these colloquia is to provide an introductory, illustrative tour of these topics at a level suitable for students and practitioners in environmental sciences, geosciences, as well as engineering and science. This Colloquium Series provides a unique opportunity to foster a dialogue between sciences, engineering, and environmental sciences.
The Effect of Connectivity of Microscopic Elements of Disordered Systems on their Macroscopic Properties: Introduction to Percolation Theory
Original event date: 4.14.05
Length: 71:49 minutes
Play using: Real Player, Windows Media
Chemical Engineering Professor Muhammad Sahimi (University of Southern California) describes percolation theory in simple terms, to quantify the effect of the connectivity of the microscopic elements of disordered systems on their macroscopic properties. Applications to problems include motor vehicle routes, conductivity, oil extraction, chemical reactivity, and voting behavior
Full abstract, biography (PDF)
Transient Dynamics: The Key to Ecological Understanding
Original event date: 4.21.05
Length: 60:17 minutes
Play using: Real Player, Windows Media
Mathematics Professor Alan Hastings (University of California, Davis) presents relevant ecological time scales and the relevance of asymptotic analysis. Arguing through the use of examples, and using ideas drawn from dynamical systems, he discusses the importance of transients, and how their presence may be analyzed mathematically.
Full abstract, biography (PDF)
Some Thoughts About Stochastic Hydrologic Modeling Inspired by the Canadian Wilderness
Original event date: 4.28.05
Length: 58:47 minutes
Play using: Real Player, Windows Media
Career hydrologist Vit Klemes (National Hydrology Research Institute of Environment Canada) presents possible ways of “irrigating the dry logic” of stochastic hydrological modeling. Most scientific predictions about the behavior of the real wet water are often based on the behavior of rather dry logical constructs, mathematical models fitted to pure numbers whose original hydro meaning does not enter the picture.
Full abstract, biography (PDF)
Nonextensive Statistical Mechanics - Introduction and Applications
Original event date: 5.12.05
Length: 77:44 minutes
Play using: Real Player, Windows Media
Boltzmann-Gibbs Statistical Mechanics is constructed upon hypotheses that many nonlinear dynamical systems do not satisfy. It is nevertheless possible to theoretically handle important classes of them through a generalization of the Boltzmann-Gibbs entropy. Its dynamical foundations are provided with illustrative applications. Constantino Tsallis from the Santa Fe Institute speaks on this subject.
Full abstract, biography (PDF)
Process Pattern, Prediction: Understanding Complexity in Driven Dynamical Systems
Original event date: 5.19.05
Length: 62:17 minutes
Play using: Real Player, Windows Media
The ability to forecast the extreme events of the future is limited by the dynamical process of interest, the space-time patterns that can be observed, and the accuracy of the predictions that are desired. Using space-time patterns and whatever is known about the dynamics of high-dimensional nonlinear earth systems, John Rundle (University of California, Davis) explains that it possible to construct numerical simulations that can be used to make predictions about the space-time evolution of systems and the possible occurrence of extreme events such as earthquakes.
Full abstract, biography (PDF)
Ants and Genes: Lessons from Collective Intelligence From Social Insects to Gene Regulatory Systems
Original event date: 5.26.05
Length: 69:03 minutes
Play using: Real Player, Windows Media
Computer sciences professor Christian Jacob (University of Calgary) gives examples of how to use evolutionary computing to breed swarm behaviors. Using an agent-based model of a gene regulatory system as example, he expands the notion of swarm intelligence to the simulation of processes within a bacterial cell, which makes highly complicated biological processes more accessible to computer-based investigations. He concludes by demonstrations of SwarmArt, an exploratory art project.
Full abstract, biography (PDF)
Multiagent Dynamical Systems
Original event date: 6.02.05
Length: 56:45 minutes
Play using: Real Player, Windows Media
Modeling multiagent systems using dynamical systems theory is possible by deriving a class of macroscopic differential equations that describe mutual adaptation in agent collectives. Starting from a discrete-time stochastic (microscopic) model, the resulting dynamical systems show that the agents' adaptation is a dynamic balance between optimization of actions that achieve rewards (exploitation) and randomization that chooses suboptimal, but novel actions (exploration). Jim Crutchfield from the University of California, Davis presents.
Full abstract, biography (PDF)
Exploring Chemical Reaction Networks in Science and Technology
Original event date: 10.06.05
Length: 64:10 minutes
Play using: Real Player, Windows Media
Network architecture has become increasingly important in understanding complex systems. Brian Higgins (University of California, Davis) focuses on chemical reaction networks in which arbitrary chemical species are connected by chemical reactions. He begins with a mathematical overview of stoichiometry, and proceeds with a review of several chemical reaction networks based on mass action kinetics that display varied dynamically properties.
Full abstract, biography (PDF)
Endogenous versus Exogenous Origins of Crises
Original event date: 10.12.05
Length: 68:24 minutes
Play using: Real Player, Windows Media
This presentation from Didier Sornette (University of California, Los Angeles) reviews a general strategy for understanding the organization of several complex systems under the dual effect of endogenous and exogenous fluctuations. Examples are: earthquake foreshocks, mainshock, aftershocks, Internet download shocks, book sale shocks, social shocks, financial volatility shocks, and financial crashes. Applications to illnesses and climate are discussed.
Full abstract, biography (PDF)
From Complexity to Peace
Original event date: 10.20.05
Length: 74:00 minutes
Play using: Real Player, Windows Media
Carlos Puente (University of California, Davis) explains (a) how recent universal results pertaining to multiplicative cascades and fully developed turbulence entice all of us to seek peace in a condition typified by the hypotenuse of a right-angled triangle; (b) how recent universal results pertaining to the transition from order to chaos via a cascade of bifurcations point us to a serene state, symbolized by the convergence to the origin in the root of a Feigenbaum's tree (c) how recent universal results pertaining to power-laws, self-organized criticality and space-filling transformations provide reminders that point us to unity as an essential element to achieve peace.
Full abstract, biography (PDF)
Networks, Power Laws, and Phase Transitions
Original event date: 10.27.05
Length: 58:24 minutes
Play using:Real Player, Windows Media
Raissa D'Souza (University of California, Davis) begins by surveying characteristic structures for different types of networks. An optimization model of "competition induced preferential attachment" is presented. Certain aspects of Internet growth that have not been captured by previous models emerge from the framework.
Full abstract, biography (PDF)
Natural hazards as self-organizing complex systems
Original event date: 11.03.05
Play using: Real Player, Windows Media (62:00 minutes)
Three cellular automata models have direct applications to natural hazards: the sand-pile model to landslides, the forest-fire model to forest and wild fires, and the slider-block model to earthquakes. The relationship of these models to critical point phenomena is discussed by Don Turcott (University of California, Davis), in particular the relationship of the forest-fire model to the critical-point behavior of the site percolation model.
Full abstract, biography (PDF)
The Prospects and Perils of Complex Systems Modeling
Original event date: 11.10.05
Webcast: Real Player, Windows Media (59:00 minutes)
Melanie Mitchell (Portland State University) reviews several prominent complex-systems models as examples of the prospects and perils of modeling techniques. These examples will range from explorations of the simplest cellular automata to detailed "agent-based" simulations of food webs, economic systems, and human behavior.
Full abstract, biography (PDF)
Insights into Complex Networks
Original event date: 11.17.05
Webcast: Real Player, Windows Media (60:53 minutes)
Michelle Girvan (Santa Fe Institute) discusses the interplay between network structure and system dynamics in many of the aforementioned systems, reviewing recent advances in the field of complex networks. Examples include the Internet, the World-Wide Web, distribution networks, neural networks, biochemical networks, food webs, and social networks.
Full abstract, biography (PDF)
Nonlinear Dynamics, Modeling, and the Environmental Sciences: Ideas and Tools
Original event date: 12.01.05
Webcast: Real Player, Windows Media (60:25 minutes)
Liz Bradley (University of Colorado) begins with a review of some of the most basic ideas and tools of the field of nonlinear dynamics, and then covers a variety of examples ranging from environmental science and engineering to dance. Most tools were developed for low-dimensional systems and many require perfect models. Since these situations are rare in the environmental sciences, she explains how and when to use them, how to interpret the results, and how to recognize their failure modes.
Full abstract, biography (PDF)
This Special Colloquium Series was made possible by the generous contributions from:
College of Agriculture and Environmental Sciences
John Muir Institute of the Environment
Computational Science and Engineering Center
Department of Land, Air, and Water Resources
Department of Civil and Environmental Engineering
Department of Chemical Engineering and Materials Science
Atmospheric Sciences Graduate Group
Hydrologic Sciences Graduate Group
Groundwater Hydrology Program, University of California Cooperative Extension