Events
Past Event
WED@NICO SEMINAR: Richard Lueptow, McCormick School of Engineering "Mixing by Cutting and Shuffling: Remarkably Persistent Structures"
Northwestern Institute on Complex Systems (NICO)
12:00 PM
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Lower Level Chambers Hall
Details
Mixing by Cutting and Shuffling: Remarkably Persistent Structures
Speaker:
Richard Lueptow - Professor of Mechanical Engineering and Senior Associate Dean for Research, McCormick School of Engineering
Talk Abstract:
Engineers and scientists think of mixing in terms of diffusion, chaotic advection (stirring), or turbulence. However, mixing can also be accomplished by cutting and shuffling, like that used to mix a deck of cards or the colors of a Rubik's Cube. While other means of mixing have long been studied, mixing by cutting and shuffling is not well explored or understood. Unlike the stretching and folding characteristic of chaotic advection, cutting and shuffling maps do not stretch the material and exhibit no chaotic behavior in the usual sense—yet they can mix quite efficiently under certain conditions. In a 3D geometry, a physical model of cutting and shuffling is a spherical tumbler that is half-filled with a granular material undergoing a bi-axial rotation protocol—a rotation about one axis followed by a rotation about another axis for each iteration. X-ray visualization of the flowing granular material reveals non-mixing regions. Simulations of the granular system confirm the non-mixing regions. To further explore cutting and shuffling of a hemisphere, the problem can be mathematically formulated as a Piecewise Isometries (PWIs) transformation that cuts an object into a finite number of pieces and rearranges them into the object's original shape. Computationally recording the cut locations from the PWI on the hemispherical shell yields beautifully intricate complex patterns. However, the PWI transformation requires the assumption of a non-physical granular flow. Hence, it is remarkable that non-mixing regions identified using PWIs correspond to surprisingly persistent non-mixing regions and global barriers to mixing that occur in both experiments and continuum model simulations. This extraordinary merging of the mathematics of PWIs, traditional dynamical systems approaches, and physical applications is leading toward a novel paradigm for understanding and predicting mixing in physical systems based on cutting and shuffling. Funded by NSF Grant #CMMI-1435065.
Live Stream:
To join the Meeting: bluejeans.com/8474912527
To join via Browser: bluejeans.com/8474912527/browser
Time
Wednesday, January 18, 2017 at 12:00 PM - 1:00 PM
Location
Lower Level Chambers Hall Map
Contact
Calendar
Northwestern Institute on Complex Systems (NICO)
WED@NICO SEMINAR: Blaise Aguera y Arcas, Google "Symbiogenesis, Computational Parallelism, and Complexity in Evolution"
Northwestern Institute on Complex Systems (NICO)
12:00 PM
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Lower Level, Chambers Hall
Details
Speaker:
Blaise Agüera y Arcas, VP/Fellow, CTO of Technology & Society, Google
Title:
Symbiogenesis, Computational Parallelism, and Complexity in Evolution
Abstract:
Symbiogenesis-- the fusion of formerly independent self-replicating entities into a larger self-replicating entity-- is proposed as the driving force behind evolution's "arrow of time" toward ever-increasing complexity. We'll explore an Artificial Life system as a minimal motivating example, then discuss the implications for biological evolution beyond the "standard" accounts of Major Evolutionary Transitions and "intelligence explosions" in brainy species. Energetic and computational implications will also be addressed.
Speaker Bio:
Blaise Agüera y Arcas is a VP and Fellow at Google, where he is the CTO of Technology & Society and founder of Paradigms of Intelligence (Pi). Pi is an organization working on fundamental research in AI and related fields, especially the foundations of neural computing, active inference, sociality, evolution, and Artificial Life.
In 2008, Blaise was awarded MIT’s TR35 prize. During his tenure at Google, Blaise has innovated on-device machine learning for Android and Pixel; invented Federated Learning, an approach to decentralized model training that avoids sharing private data; and founded the Artists + Machine Intelligence program.
An External Professor at Santa Fe Institute and a frequent public speaker, Blaise has given multiple TED talks and keynoted NeurIPS. He has also authored numerous papers, essays, op-eds, and chapters, as well as two previous books, Who Are We Now? and Ubi Sunt. His most recent book, What Is Life?, is part 1 of the larger book What Is Intelligence?, forthcoming from Antikythera and MIT Press in September 2025.
Location:
In person: Chambers Hall, 600 Foster Street, Lower Level
Remote option: https://northwestern.zoom.us/j/98741396308
Passcode: NICO25
About the Speaker Series:
Wednesdays@NICO is a vibrant weekly seminar series focusing broadly on the topics of complex systems, data science and network science. It brings together attendees ranging from graduate students to senior faculty who span all of the schools across Northwestern, from applied math to sociology to biology and every discipline in-between. Please visit: https://bit.ly/WedatNICO for information on future speakers.
Time
Wednesday, November 12, 2025 at 12:00 PM - 1:00 PM
Location
Lower Level, Chambers Hall Map
Contact
Calendar
Northwestern Institute on Complex Systems (NICO)
Data Science Nights - November 2025 - Speaker: Feihong Xu, ESAM
Northwestern Institute on Complex Systems (NICO)
5:30 PM
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Lower Level, Chambers Hall
Details
NOVEMBER MEETING: Thursday, November 20, 2025 at 5:30pm (US Central)
LOCATION:
In person: Chambers Hall, Lower Level
600 Foster Steet, Evanston Campus
AGENDA:
5:30pm - Meet and greet with refreshments
6:00pm - Talk with Feihong Xu, Amaral Lab, ESAM
Talk title and abstract TBA.
DATA SCIENCE NIGHTS are monthly meetings featuring presentations and discussions about data-driven science and complex systems, organized by Northwestern University graduate students and scholars. Students and researchers of all levels are welcome! For more information: http://bit.ly/nico-dsn
Time
Thursday, November 20, 2025 at 5:30 PM - 7:30 PM
Location
Lower Level, Chambers Hall Map
Contact
Calendar
Northwestern Institute on Complex Systems (NICO)
Data Science Nights - December 2025 - Speaker: Yash Chainani, Chemical Engineering
Northwestern Institute on Complex Systems (NICO)
5:30 PM
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Lower Level, Chambers Hall
Details
DECEMBER MEETING: Thursday, December 18, 2025 at 5:30pm (US Central)
LOCATION:
In person: Chambers Hall, Lower Level
600 Foster Steet, Evanston Campus
AGENDA:
5:30pm - Meet and greet with refreshments
6:00pm - Talk with Yash Chainani, Broadbelt & Tyo Labs, Chemical Engineering
Talk title and abstract TBA.
DATA SCIENCE NIGHTS are monthly meetings featuring presentations and discussions about data-driven science and complex systems, organized by Northwestern University graduate students and scholars. Students and researchers of all levels are welcome! For more information: http://bit.ly/nico-dsn
Time
Thursday, December 18, 2025 at 5:30 PM - 7:30 PM
Location
Lower Level, Chambers Hall Map
Contact
Calendar
Northwestern Institute on Complex Systems (NICO)