Chaos and Complex Systems Seminar
Fall 1995 Seminars
Dates, speakers, titles and abstracts will be listed as they become
All seminars will meet in 5134 Chamberlin, at 12:05 Wednesdays,
as noted. At the moment this very bare, to say the least!
- September 20. William Brock: ``Stock
in Complex Environments.''
- September 27. Richard Belew:
in Evolving Populations: Models and Algorithms.''
- October 4. Larry Getzler: ``Bifurcations
- October 11. Tim Allen: ``What Is Chaos
As Much As You Think.''
- October 18. Joel Robbin: ``Lyapunov
- October 25. Una-May O'Reilly: ``A
to Understanding Genetic Programming.''
- November 1. No seminar (but see below).
- November 8. Ron Burnette: ``Analysis of
of Aging on Human Hemodynamics and Its Impact on Drug Action.''
- November 15. Paul Plummer: ``Nonlinear
Spatially Interdependent Markets.''
- November 22. Open.
- November 29. Scott Page: ``Problem
of Hetereogeneous Agents.''
- December 6. Open.
- December 13. George Sugihara:
from Natural Time Series.'' --- CANCELLED.
- December 20. Organizational meeting.
September 20. William Brock, UW Economics.
Price Modelling in Complex Environments.''
No abstract yet.
Abstract: Even the simplest creature is marvelous to observe
it transforms itself to better match the environment in which it
itself. How is such adaptation accomplished? How much of this
should be attributed to the particular individual we happen to be
how much to its species, and how much to the inclusive evolutionary
wedding all life to this planet? How did the elaborate individual
process we find in complex organisms evolve? Once in place, how does
increased individual capacity for adaptation alter the selective
causing the species to adapt to its niche?
This talk will give an overview of a book (of the same
edited by R. K. Belew and Melanie Mitchell, to be published soon
The book grew out of a workshop at the Santa Fe Institute which
together a group of about 20 scientists from biology, psychology,
science, all studying interactions between the evolution of
and individuals' adaptations in those populations, and all of whom
some use of computational tools in their work. A good example is
effect,'' a phenomena identified by the psychologist J. Mark
exactly a century ago, that arises repeatedly in many modern
This talk will touch on the rich historical heritatge of such
ranging from biologists like Lamarck and Waddington to
Piaget and Skinner, as well as the new insights offered by
and new algorithms inspired by the same insights.
October 4. Larry Getzler, UW Economics.
in Industrial Location.''
Abstract: If initial conditions were slightly different,
the North American industrial belt been located elsewhere, or have
several small geographically disperse industrial centers instead? To
this and other issues I have created a dynamic plant location model
multiple firms and products, as well as spatially diverse inputs and
In the model, geographic patterns of industrialization depend on
locations of demand, strength of demand at different locations,
costs for inputs, transport costs for outputs, input prices, input
and the locations of competitors. Firms act as price discriminating
when there are no competitors close enough to be able to undercut
I implement this model by performing a series of computer
For some large ranges of initial conditions essentially the same
patterns occur. However, there are frontiers (bifurcations) where
difference in initial conditions leads to drastically different
A monotonic change in a single condition, the marginal cost of
inputs, can cause firms to make large spatial jumps back and forth
coordinates in their location choice. The multiple causes of these
October 11. Tim Allen, UW Botany. ``What Is
For? Not As Much As You Think.''
No abstract yet.
October 18. Joel Robbin, UW Math. ``Lyapunov
No abstract yet.
October 25. Una-May O'Reilly, AI Lab, MIT
1996). ``A Comparative Approach to Understanding Genetic
Abstract: Genetic Programming (GP) [Koza, 1993] is a Genetic
specialized to perform program induction (i.e. the automatic
of a computer program from a set of input-output pairs). As a GA it
inspired by the adaptive process of evolution and has computational
crudely equivalent to ``survival of the fittest'', reproduction and
I shall introduce GP and compare it to two well understood
search algorithms: Iterated Hill Climbing and Simulated Annealing.
three algorithms are used to solve the same suite of program
problems, posed in exactly the same style. The comparison
evaluates the optimization power of the evolution-based GP
I also uncouple the ``genetic crossover'' operator of GP and use
as the search operator in Hill Climbing and Simulated Annealing.
are two reasons for this: to understand whether the resulting
induced ``fitness landscapes'' [Sewall Wright] are amenable to
search and to evaluate the role of recombination when the
is used in GP.
November 1. No seminar.
However, there is a talk of possible interest: Ivar Ekeland,
of Mathematics at the University of Paris-Dauphine, and author of
the best popular books on chaos and nonlinear dynamics (Mathematica
the Unexpected) will be giving a Hilldale Lecture on
Principles and Symplectic Geometry: From Galileo's Pendulum to
Geometry''. (Place: room B130, Van Vleck Hall;
Nov. 1, 4:00 pm.)
November 8. Ron Burnette, UW Pharmacology.
of the Influence of Aging on Human Hemodynamics and Its Impact on
Abstract: Biological systems are extremely complex and one
argue that human beings represent the most complex of the biological
Assuming this to be true, one wonders how it is posssible for
to have any hope of treating patients in an optimal fashion? What
this question of even more concern is that a clinician functions in
extremely data poor environment.
The purpose of this seminar is to try to partially answer this
in a restricted sense, by using the techniques of principal
constrained Monte Carlo simulation, sensitivity analysis and graph
Every attempt will be made convey this material from a qualitative
viewpoint along with providing needed biological background
November 15. Paul Plummer, UW Geography.
Dynamics in Spatially Interdependent Markets.''
Abstract: Typically, attempts to explain spatial variations
profits, and outputs have concentrated on developing models of
price equilibria. However, such equilibria are only of interest if
be shown that they are stable in the sense that firms pursuing a
adjustment strategies tend to drive the market towards an
of prices, profits and outputs in a sufficiently short time period.
this presentation, I examine the disequilibrium dynamics of a model
intra-urban spatial competition in which oligopolistically
firms sell a relatively homogenous commodity directly to consumers.
on three questions: the conditions under which the model converges
spatial price equilibrium; the nature of the space-time dynamics of
price and profit differentials during the period of disequilibrium
to spatial price equilibrium; the diffusion of price changes
the configuration of the urban market.
November 29. Scott Page, Dept. of Economics,
Institute of Technology. `Problem Solving by Teams of
(Co-author, Lu Hong, Dept. of Economics, Syracuse University.)
Abstract: We construct a model of problem solving by teams of
agents with limited ability which elucidates differences between
solving firms and manufacturing firms. The heterogeneity refers to
in how individual problem solvers perceive problems and in how they
to solve them. These differences enable teams of problem solvers to
individuals. In applying this model of heterogeneous problem solvers
production theory, we arrive at some uncomfortable conclusions:
that arbitrary returns to additional problem solvers are possible
a team of people of ``equal ability'' applied to a single problem
exhibit increasing returns or decreasing returns depending upon the
they are hired. We can formulate assumptions which generate
returns, but they rely on such pessimistic assessments of the
of problem solvers so as to be unrealistic.
December 13. George Sugihara, Scripps
Oceanography, UC San Diego. ``Extracting Nonlinearity from Natural
Series.'' --- CANCELLED
Abstract: Although identifying chaos in real data sets is a
subject, there is much to be gained by focusing on the nonlinearity
may be found in certain time series data. Here I review some of the
concerning the detection of nonlinearities and possible chaos in
particularly with regard to stochastic chaos. I will also discuss
examples, where characterizing and exploiting nonlinearity can
some fundamental insights about nature. Among these, is a
using atmospheric data that shows how one can extract the functional
of the dominant nonlinear signal. This signal, in turn, is used to
insight into the underlying mechanisms involved and can lead to
CANCELLED! Dr. Sugihara has unfortunately come down with
December 20. Organizational meeting.
Usual time and place; to decide on time and place for next
possible speakers, and other administrivia.
Up to the Chaos and Complex Systems Seminar
(Tue Dec 12 15:30:26 CST 1995)