Madison Chaos and Complex Systems Seminar

Spring 2020 Seminars

All seminars are Tuesday at 12:05 pm in 4274 Chamberlin Hall except as noted. Refreshments will be served.

Short List
Join us for lunch during the summer on the Memorial Union Terrace at noon each Tuesday, starting May 5th!


January 21, 2020

Color: Physics and perception

Pupa Gilbert, UW Department of Physics

Unless we are colorblind or are in the dark, as soon as we look at any object, we know what color the object is. Simple, isn’t it? No, not really. The color we see is rarely just determined by the physical color, that is, the wavelength of visible light associated with that color. Other factors, such as the illuminating light, or the brightness surrounding a certain color, affect our perception of that color. Most striking, and useful, is understanding how the retina and the brain work together to interpret the color we see, and how they can be fooled by additive color mixing, which makes it possible to have color screens and displays. I will show the physical origin of all these phenomena and give live demos as I explain how they work. Bring your own eyes!

For more information: (1) watch TED talk: “Color: Physics and Perception” and (2) read book: PUPA Gilbert and W Haeberli “Physics in the Arts”, ISBN 9780123918789.

January 28, 2020

A conditional Gaussian framework for assimilating and predicting complex nonlinear turbulent dynamical systems

Nan Chen, UW Department of Mathematics

A conditional Gaussian nonlinear and non-Gaussian framework is developed and is applied to study data assimilation, uncertainty quantification and prediction of complex nonlinear turbulent dynamical systems. The talk will contain the following topics: recovering turbulent ocean flows, predicting non-Gaussian atmosphere phenomena including extreme events, solving the time evolution of high-dimensional probability density function, parameter estimation and recovering the hidden states in complex systems.

February 4, 2020

Anesthesia in the Anthropocene: Environmental and economic considerations of modern anesthesia and surgery

Mike Ries, UW Department of Anesthesiology

Climate health and population health are undeniably and inextricably linked. As healthcare institutions maintain a moral obligation to the healing of all the world's citizens, and healthcare being a significant, environmentally burdensome business, there exists a large motive and opportunity for "greening" healthcare. Even further, the operating room has been singled out as the most polluting and most energy-intensive part of the modern healthcare ecosystem. As the perioperative expert, this places a moral and economic obligation on anesthesiologists to improve environmental standards in the operating room. During this talk we will discuss the complex environmental and economic problems facing the healthcare industry and more specifically how "greening" the OR is the right choice for checkbooks and our environment alike.

February 11, 2020

Learning with scarce data: The role of side information, simulators, and GANs

Kangwook Lee, UW Department of Electrical and Computer Engineering

In this talk, I will present the role of side information, simulators, and GANs for learning with scarce data.  In the first part, I will talk about the role of similarity graphs in recommendation systems.  In the second part, the role of simulators and GANs will be discussed.

February 18, 2020

Drivers of megadiversity in the orchids, the largest family of flowering plants

Tom Givnish, UW Department of Botany

Orchids are the most diverse family of angiosperms, with more species than mammals, birds, and reptiles combined. Many ideas have been advanced to account for their extraordinary diversity, but they have – until quite recently – been impossible to test because we lacked a good phylogeny (family tree) for the orchids. My colleagues and I have now developed a well-resolved phylogeny for the orchids, based on large numbers of chloroplast genes, and I will show how we can use this phylogeny to identify the age and place of origin of the orchids, assess the role of different orchid traits in driving high rates of speciation, and reconstruct the geographic spread of orchids across the planet. I will also describe some of the remarkable aspects of the ecology of this endlessly fascinating group that have recently come to light, mention some of the notable aspects of orchid diversity in Wisconsin, and sketch some interesting scientific and conservation issues that should be explored in the future.

February 25, 2020

The emergence of human emotions: Learning, development and biology

Seth Pollak, UW Department of Psychology

Theories about the emergence of human emotion have traditionally emphasized evolutionarily preserved, universal aspects of emotion or the functional and cultural adaptations of emotions. While these opposing views make different assumptions about the initial state of emotion in the brain, both theories devote little attention to or specification about potential processes for learning and developmental change. This colloquium will focus on the question of how brain and behavior are shaped and refined by children's early social and emotional experiences. To do so, I will describe recent research involving children who have experienced aberrant early life experiences. These include child abuse and neglect, children raised in extreme poverty, children raised in institutional settings, and children who have endured traumatic life experiences. Studies of these children provide new insights about the developmental processes underlying socio-emotional learning as well as shed light on the mechanisms through which children acquire emotions. In addition to these basic science questions, children raised in adverse environments are at increased risk for a variety of health, academic, and social problems. I will highlight ways in which research in this area can both address central issues in human development as well as hold tremendous promise for improving the health and well-being of children.

March 3, 2020

The complexities of conveying hurricane forecast uncertainty to the public

Derrick Herndon, Space Science and Engineering Center

Tropical Cyclones (Hurricanes) are one of the most violent and dynamic storms on our planet.  Each year an average of 80 tropical cyclones develop over the warm tropical oceans.  Most of these storms spin harmlessly at sea.   Others bring extreme winds, torrential rainfall and surges from the ocean ashore to devastating effect.  Significant progress has been made in our ability to forecast the development and track of these storms over the last few decades.  However, substantial challenges remain.  Our ability to forecast the internal dynamics that drive the changes in storm intensity have not quite kept pace with other aspects of the forecast problem.  Providing accurate and meaningful forecast information for an inherently chaotic system to the public is also a continuing challenge.  This talk will explore recent advances in our understanding of these storms along with some remaining challenges related to the complex interactions between people and hurricanes.

March 10, 2020

The role of turbulence in the universe

Siyao Xu, UW Department of Astronomy

Turbulence is everywhere in our daily life. The same turbulence in our blood vessels, coffee, rivers, etc. also exists in the universe over a vast range of length scales from planets to the large scale structure of the universe. The same physics of turbulence, including mixing, diffusion, dynamo amplification, applies to diverse astrophysical environments. This talk will introduce astrophysical turbulence and its power in connecting different astrophysical phenomena, from the most energetic explosions in the universe to our Sun.