Madison Chaos and Complex Systems Seminar
Fall 1997 Seminars
Dates, speakers, titles and abstracts will be listed as they become
available. Meetings will be noon Tuesdays in 4274 Chamberlin Hall
unless otherwise noted.
- 2 September. No meeting.
- 9 September. Ray Kent: ``Sounding Off in
the First Year of Life: The Complex System of Infant
- 16 September. Cosma Shalizi: ``Uncovering
Structure and Understanding How Nature Computes: The Program of
- 23 September. George E. Hrabovsky:
``Tornadoes and the Development of Unpredictability.''
- 30 September. Edward R. Pope:
``Algorithmic Art: Beginnings, Some Present Directions.''
- 7 October. Deric Bownds: ``The Evolution
of Human Minds.''
- 14 October. Rick Lindroth: ``Chemical
Ecology of Aspen: Environment-Plant-Insect-Pathogen
- 21 October. Teresa Hayden: ``Complex
Systems and Problematic Human Behavior.''
- 28oct. Dave Albers: ``Routes to Chaos in
Neural Networks with Random Weights.''
- 4 November. Bill Lytton: ``Dynamics of
- 11 November. Rus Yukhananov:
``Bifurcation Model of Drug Dependence.''
- 18 November. Jean-Paul Chavas: ``Chaos in
- 25 November. Marcie Myers: ``Can
Nonlinear Methods Help Us Understand the Dynamics of Human
- 2 December. Clint Sprott: ``The Science of
- 9 December. Joe Newman: ``Response
Modulation Deficits in Psychopaths.''
9 September. Ray Kent, UW Communicative
Disorders: ``Sounding Off in the First Year of Life: The Complex
System of Infant Vocalization.''
Beginning with the birth cry and proceeding through grunts, babbles,
and maybe first words, the typical infant accomplishes a number of
vocal milestones in this so-called ``prespeech'' period from birth
to one year of age. This talk reviews some recent perspectives from
complex systems theory as they relate to vocal development.
16 September. Cosma Shalizi,
UW Physics: ``Uncovering Structure and Understanding How Nature
Computes: The Program of Computational Mechanics.''
The problem of discovering structures or regularities in nature is
ancient, but one of best example of why it is a problem
comes from the fairly recent study of chaotic dynamical systems,
where the surface data (apparently pure noise) conceal very regular
patterns (strange attractors), which eluded detection for decades.
``Computational mechanics'' is a still-developing body of
techniques, drawing on statistical physics, and the theories of
dynamical systems and computation, for discovering causal structures
and characterizing them in computational terms. In addition to its
use in the natural sciences, it may help settle long-standing and
acrimonious debates about the sense in
which natural objects (like brains) can be said to compute. I will
a little on the philosophical and methodological background, go over
some (simple) examples of how the techniques can be applied, and
conclude by hand-waving about computation in nervous systems.
23 September. George E. Hrabovsky, UW
Physics: ``Tornadoes and the Development of Unpredictability.''
For forty years the meteorological community has wrestled with the
problem of predicting severe weather in general, and tornadoes in
particular. Beginning with the SELS (SEvere Local Storms) unit,
several large-scale atmospheric correspondences were noted in the
mid- to late-fifties. These observations allowed the first severe
weather watches to be issued. In the sixties we saw the advent of
weather radar in widespread use and weather reconnaisance satellites
both of which improved the success rate of the severe weather
watches. In the seventies we saw the advent of Doppler radar,
numerical simulations of thunderstorms, and the first true
scientific storm chasing; these developments combined to produce a
model of tornado formation which has stood until the last three
years. It was thought until recently that Doppler radar could detect
tornadic circulations as much as a half hour before the tornado
formed, all that had to be done was to warn the public; it seemed to
be a panacea. We are beginning to realize that Doppler radar cannot
do this and may not be able to detect tornadic circulations farther
than a few kilometers from the radar. This then is the development
30 September. Edward R. Pope, UW Art:
``Algorithmic Art: Beginnings, Some Present Directions.''
This talk will provide a brief review of the history of algorithmic
art, and a discussion, with visual examples, of the aesthetic
concepts and realization of such work contemporarily.
7 October. Deric Bownds, UW
Zoology: ``The Evolution of Human Minds.''
Abstract: This talk is a brief review of contemporary
models describing each of us as a society of mind that emerges from
our evolutionary history and the details of how our brains form as
we grow up in a particular natural ecology and cultural setting.
14 October. Rick Lindroth, UW Entomology:
``Chemical Ecology of Aspen: Environment-Plant-Insect-Pathogen
Abstract: Quaking aspen (Populus tremuloides) is
the most widely distributed tree species in North America. It occurs
in a great diversity of habitats and plays a central role in the
ecological dynamics of early successional forests. Fundamental
insights into the ecological interactions of aspen have been
afforded by evaluation of the role of chemistry (especially
``defensive'' compounds) in such interactions. Aspen exhibits
tremendous chemical variation in the field. Such variation is a
consequence of genetic variability interacting with differential
availability of resources (light, nutrients, CO2). Chemical
variation in turn influences the interactions of aspen with insect
herbivores, and the interactions of herbivores with their own
natural enemies. This complex interplay of bottom-up and top-down
ecological processes through evolutionary time is responsible for
production of the current mosaic of chemical phenotypes in aspen
21 October. Teresa Hayden, UW Psychology:
``Complex Systems and Problematic Human Behavior.''
Abstract: How might Clinical psychologists apply some of
the concepts of complex systems theory to understanding everyday
personal problems? In this non-mathematical talk I will derive a
meta-model of problematic human behavior from the four major schools
of Psychotherapy. This meta-model describes patterns of problematic
behavior which are often repeated in various situations and for long
periods of time. Given the repetitive character of problematic
behavior, we could then ask about some possible features of these
iterating patterns: Will new properties emerge? What are some
candidates for control parameters in these systems? What might be
the role of consciousness in change?
28 October. Dave Albers, UW Physics:
``Routes to Chaos in Neural Networks with Random Weights.''
Abstract: Neural networks are universal approximators; they
can be used to model any dynamical system. I will discuss a Monte
Carlo study of the dynamical behavior of neural networks with
randomly chosen connection strengths. I will show that as the
networks become more complicated, the probability that they exhibit
chaotic dynamics approaches unity. I will present theoretical and
experimental results showing that as the dimension of the networks
increases, the quasi-periodic route to chaos dominates. I will also
qualitatively describe the dynamics along the route to chaos.
4 November. Bill Lytton, UW Neurology:
``Dynamics of Stroke Recovery.''
Abstract: A simple neural network was used to model
physiological data from cells surviving a stroke in visual cortex.
Immediate changes observed experimentally included both expansions
and contractions in the range of stimuli (receptive field) to which
an individual cell would respond, and alterations in maximal
activation levels. Observed changes could be largely explained by
the dynamics of the network, without any changes in connection
weights. Death of individual units directly altered the patterns of
excitation even without any change in connectivity. These activity
changes might be regarded as ``dynamic plasticity'' that would then
determine the pattern of subsequent true plastic changes through
Hebbian mechanisms (increases in connection strength between
simultaneously active units). We have now extended the network to
make behavioral predictions. This will aid in development of new
strategies for improving patients' recovery after stroke.
11 November. Rus Yukhananov, UW
Anesthesiology: ``Bifurcation Model of Drug Dependence.''
Abstract: Addiction is not an acute but a chronic relapsing
disorder. The current model of addiction, based on principles of
homeostasis, cannot explain why the disorder persists long after the
cessation of drug administration. This is an attempt to modify the
homeostatic model to explain the transition from the normal to the
addicted state. Using nonlinear equations I try to describe a
possible scenario for nervous system transformation from normal to
an addicted state, which can last indefinitely even in the absence
18 November. Jean-Paul Chavas, UW
Agricultural and Applied Economics: ``Chaos in Dairy Land.''
Abstract: The U.S. dairy markets have seen a sharp increase
in instability over the last two years. A nonlinear dynamic model is
developed and estimated. It shows that market instability and chaos
are linked to there important factors: the dynamics of the cow herd,
the inelasticity of demand for dairy products, and recent changes in
government dairy pricing policy.
25 November. Marcie J. Myers, UW Biology
Core Curriculum: ``Can Nonlinear Methods Help Us Understand the
Dynamics of Human Movement?''
Rhythmic movement in humans and other animals is presumably the
result of complex dynamic interactions between morphology
(musculo-skeletal system, inertial properties), neural input
(central nervous system pattern generators, peripheral inputs,
intentional influences), physiological constraints (minimization of
metabolic energy or muscular force), and environmental
perturbations. Describing, predicting and understanding the dynamic
behavior of rhythmic movements should benefit greatly from, if not
require, the application of chaos and nonlinear dynamics theory.
Indeed, during the last 10 years, nonlinear methods have been used
to model the dynamics of developmental transitions in newly running
infants, walk-to-run gait transitions in adults, movement pattern
learning, stride interval fluctuations, and the coordination of
oscillating limbs. I will review briefly some of these applications.
I will also give some background on the physics of locomotion, and
explore (in a discussion format) the usefulness of nonlinear methods
in helping us to understand the energetics of locomotion.
2 December. Clint Sprott, UW Physics: ``The
Science of Complexity.''
Abstract: Many interesting phenomena arise from the
interaction of a large number of individual components. Examples
include turbulent fluids, the stock market, the ecosystem, and the
brain. Recent advances in computing permit such systems to be
studied using simple models with a large number of variables. These
models exhibit many of the general properties of natural complex
systems such as self-organization, evolution, adaptation, and
artificial intelligence. Some of these models will be described, and
their dynamical behavior will be illustrated with computer
9 December. Joseph P. Newman, UW Psychology:
``Response Modulation Deficits in Psychopaths.''
The antisocial behavior of psychopaths leads many to conclude that
they are fundamentally callous and fearless. Our physiological,
animal model of psychopathy and the results of numerous studies
generated by the model suggest that psychopaths have a response
modulation deficit. Response modulation entails a brief and
relatively automatic shift of attention from the organization and
implemention of goal-directed behavior to its evaluation. Whereas
response modulation enables nonpsychopaths to process contextual
cues that provide perspective on behavior and facilitate
self-regulation, the psychopath's difficulty processing such cues
results in a profound, though situation specific, failure to
Up to the Chaos and Complex Systems Seminar page.
Last change worth mentioning Sun 23 Nov 1997