January 23, 2001
Math and physics in 3D computer graphics
David Camp, UW Memorial Library
I've been creating 3D computer graphics on my home PCs and posting them to the web for about four years. Advances in hardware and software are making it possible for people working in a home or office environment to produce imagery that approaches what could only be done in Hollywood a few years ago. There are now dozens of 3D art programs, but they all make use of 3D coordinate systems and the optical properties of surfaces such as diffuse light and reflection. This form of computer graphics is done by creating objects within a coordinate system, applying surface parameters, setting up lights and a camera, and then telling the computer to take a picture of the simulated scene. I will discuss this process focusing on Bryce and Ray Dream Studio, the two programs I'm most familiar with.
Ref: Sample gallery
January 30, 2001
Can a monkey with a computer create art?
Clint Sprott, UW Department of Physics
While studying chaotic dynamical systems, I inadvertently generated a few million fractal images, called Strange Attractors. These images were selected by the computer from among a few billion cases that were analyzed. I showed a few thousand of these to about a dozen artists and scientists who evaluated them aesthetically. From that I discovered a strong correlation between their aesthetic quality and mathematical properties such as fractal dimension and Lyapunov exponent. Then I was able to train the computer to be even more selective and to produce thousands of images, all different, and most which are aesthetically appealing. I will describe the process and show examples of the images produced in this way. I will even produce some new ones during the talk and will offer large original prints to anyone who will frame and display them.
Ref: Sprott's Fractal Gallery
Fractal Images Reveal Complex Dynamics
This talk is available as a PowerPoint Presentation and in HTML format.
February 6, 2001
Mathematical models of love and happiness
Clint Sprott, UW Department of Physics
Steve Strogatz has proposed a two-dimensional linear continuous-time dynamical model of the love/hate relationship between two individuals. I will describe the rich dynamics of this simple model and suggest some nonlinear extensions and models of love triangles with chaotic solutions. I will also describe a related linear model for the time evolution of one's happiness in response to external stimuli (hedonics). I will show how the models are related and will discuss some implications for psychotherapy and for a personal philosophy of life. An important implication of the happiness model is that one cannot expect to be either exclusively happy or exclusively unhappy over long periods. A similar response can occur with love/hate. Also, one's subjective feelings are more volatile and often opposite to those perceived by others.
This talk is available as a PowerPoint Presentation and in HTML format.
February 13, 2001
Why isn't growth making us happier? Utility on the hedonic treadmill
Louise Keely, UW Department of Economics
This paper constructs a preference structure grounded in psychological evidence on how one's own well-being is evaluated. Such a preference structure is analyzed in the context of an endogenous variety growth model. This model's results are consistent with, and provide a possible explanation for, the increase in income in developed economics in the post-war period that has not been accompanied by an increase in reported well-being.
February 20, 2001
Thoughts on the nature and origins of time series analysis
George Box, UW Departments of Industrial Engineering and Statistics
Frequently data occur as a sequence in time, for example measurements taken every minute, hour, day, week or month. Methods for time domain modeling of such series are briefly considered and how such models have been used, for example, in short term forecasting and quality control. The subject is introduced by considering some major advances made over the last 70 years by Beveridge, Yule, Wald, Holt and others.
February 27, 2001
Is the biomedical model of stress an example of order or disorder?
Chris Coe, UW Department of Psychology
The "stress response" has been discussed in physiology, psychology, and medicine for nearly 100 years, but which aspects are organized and adaptive, versus chaotic and maladaptive still remains unclear. Recent findings on stress-induces changes in immunity challenge us to ask why do they occur?
March 6, 2001
Economics, population biology, and statistical physics: The sciences of many-body systems
Abdol S. Soofi, Professor of Economics, UW-Platteville and Visiting Scholar, School of Business Administration, UW-Milwaukee
In this talk, first, I will present two opposing methodological views in study of economics: The mechanistic view of the early-19th-century physics and the evolutionary view of biological sciences. Next, I suggest that the traditional approaches to study of economics suffer from a fundamental misunderstanding of the exact nature of economies as many-body systems, i.e. systems made up of many parts that are classified into a few types and interconnected with a few kinds of relationships.
This suggestion is based on the idea that economies, like population biology, and statistical physics, consist of large numbers of individuals which are organized into dynamic, volatile, complex, and adaptive systems that are sensitive to environmental constraints, and that evolve according to their internal structures generated by the relationships among the individual members of the systems.
In studies of the complex systems, the use of dynamical systems theories, calculus of probability and stochastic processes, and ergodic theory which connects the first two, become imperative. Some of these theories have originated in statistical physics and are increasingly used as tools of analysis in cutting-edge, frontier research in economics and finance.
Recently, many researchers in financial economics have relied on dynamical systems theory as a powerful tool in finding answers to many lingering problems in economics for which traditional approaches were ineffective in giving solutions. Dynamical systems theory, particularly the theory of time-delay embedding and phase space reconstruction, treats a deterministic dynamic process as a one-dimensional composite system. In such a system, successive stages follow each other based on iteration of a certain rule, and which all stages are interacting with each other according to a certain law. Accordingly, deterministic dynamics studies the general features of the entire process.
Finally, as an example of dynamical systems approach to studies in economics and finance, I will present the results of some of my recent research in exchange rate modeling which are based on phase space reconstructions of exchange rates dynamics.
March 20, 2001
Out of silence: From language disorders to poetry
Robin Chapman, UW Department of Communicative Disorders & Waisman Center
The differing ways in which small differences in early experience can contribute to accelerated language learning or delay are discussed, including the roles of affective and social interaction, moderate novelty in events, and talk addressed to children (its amount, rate, content, and prosody); these same small differences contribute to the effects achieved by poems, which at their best evoke emotional content with fresh imagery, metaphor, and music.
March 27, 2001
Spatial pattern and critical thresholds in landscape dynamics
Monica G. Turner, UW Department of Zoology
Landscape ecology emphasizes the interaction between spatial pattern and ecological process--that is, the causes and consequences of spatial heterogeneity across a range of scales. Landscape ecology offers new concepts, theory and methods that are revealing the importance of spatial patterning on the dynamics of interacting ecosystems.
In this talk, I will highlight some insights about landscape pattern and ecological processes that have been derived from simple quantitative models, focusing largely on percolation theory and models derived from cellular automata that simulate dynamics on a gridded landscape. Percolation theory deals with spatial patterns in randomly assembled systems. The application of percolation theory to landscape studies has addressed a series of questions dealing with the size, shape and connectivity of habitats as a function of the percentage of a landscape occupied by that habitat type. Because percolation theory generates pattern in the absence of specific processes, the comparison of random maps with actual landscapes provides a neutral model capable of defining the significant departures from randomness of patterned landscapes. This theory has suggested the importance of critical thresholds in connectivity of habitat that, in turn, may influence a variety of ecological processes.
April 3, 2001
Mind-blowing similarities in the way that information is stored, transferred, and used in the respective worlds of silicon and carbon.
Bernard Weisblum, UW Department of Pharmacology
Abstract available in pdf format at http://sprott.physics.wisc.edu/Chaos-Complexity/Weisblum.pdf
April 10, 2001
The cool early Earth: Evidence for liquid water on Earth 4.4 billion years ago
John W. Valley, UW Deparrment of Geology and Geophysics
The mineral zircon preserves the best record of U-Pb age and
isotope composition of magmatic events. A systematic study
zircons from all ages of rock shows more primitive oxygen isotope
(5-7.5) in the Archean (older than 2.6 Ga), and has led to the
of the oldest recognized piece of the Earth, a 4.404 Ga detrital
from the Jack Hills, Western Australia. The high oxygen
of the core of this crystal (7.4), the presence of inclusions of
and the rare earth element compositions suggest
that it came from continental crust that was enriched in the heavy isotopes of oxygen by interaction of liquid water with the magma protolith at the surface of the Earth. Thus, low temperature conditions prevailed approximately 150 m.y after the formation of the Earth, and 50-100 m.y. after the formation of the Earth's core and the Moon. These conclusions contrast with widely accepted ideas about an Early Hot Earth and lead to speculation about the timing and frequency of the origin of life.
April 17, 2001
Finding patterns in gene expression profiles
Michael Newton, UW Department of Statistics
April 24, 2001
The deep illness of the modern mind: Linear modern mind ill-prepared for a huge set of non-linear bifurcations.
Jim Gustafson, UW Department of Psychiatry
The epidemic illness of our time is our subject: its structure, variations, and treatment. Essentially, the aboriginal mind was and is an integrative mind, transitional between all the great opposites of nature, like hot and cold, dry and rainy, light and dark, fresh and rotting, and so forth. Put such a mind into the modern world of linear programs (schooling, assembly lines, consumer purchasing, entertainment, etc), and you have got an isolated linear will disconnected from all its opposites and alarmed by all of them. We will consider as many of these bifurcations as we have time for in an hour: starting with the bifurcation of the head (the leading part of the personality, or mask) from the body (in shadow), the abstract from details, scientific will from romantic will, reason from unreason, vast scale from small scale, etcetera.
May 1, 2001
Experience-dependent processes in the organization of affect
Seth Pollak, UW Departments of Psychology, Psychiatry, and Pediatrics and Waisman Center
Beginning with Darwin (1872), there have been opposing hypotheses regarding the initial state of the complex systems that children use to recognize what others are feeling. The nativist position is supported by evidence such as the production of facial expressions very early in post-natal life and cross-cultural similarities in emotion recognition. The contrasting empiricist argument, that recognition of emotion is learned through experience, is based upon the gradual refinement with age of children's production and recognition of emotional signals. Parsing the relative contributions of experience and learning versus internal predispositions for emotion remains complicated, however, because children are virtually always exposed to rich, complex, and perhaps even cross-culturally similar emotional experiences from birth. This talk will focus on the influences of learning in the ontogenesis of emotional processing by employing "natural experiments" involving children who have had atypical emotional experiences.
May 8, 2001
Smiles at the interface of physics and biology in the genomic revolution
Mike Sussman, UW Biotechnology Center
There is a revolution going on in the field of biology. The elucidation of the complete DNA sequence for the human and plant genomes represents a landmark that some have likened to the birth of the periodic table in chemistry 150 years ago. The genome sequences represent the book of instructions for building these living organisms. We are now in the midst of what insiders call 'functional genomics', i.e., study of the function for the ca. 35,000 genes in the human genome and the ca. 25,000 genes in the plant genome. We only have hints on the functions for half of these-these unknown genes are perhaps like the missing mass of the universe-we suspect they are important and they exist, but we have no clues on what they do or why they are there. A key part of the biological revolution is the development of new technologies for the high throughput analysis of genes and proteins. Up to the last couple of years, biologists spent their PhD's (and their careers) studying only a handful of genes. Now we study 25,000 genes in one afternoon! There are huge opportunities for engineers and physicists to develop new technologies for miniaturizing genomic analyses. In addition, since cellular structures operate in the nanometer and micrometer region, biology and physics is meeting in an area called nanotechnology. Life spent three billion years evolving fantastic machines that solve problems of moving mass and energy. For example, diatoms build little glass houses, and their golgi apparatus acts as a living lithography machine. The fun and excitement is at the interface of biology and physics these days. This interface is chaotic.