PICS Colloquium: “Finding sensitivity in the long-exposure of chaotic dynamical systems” with Qiqi Wang

Friday, November 8, 2018 Qiqi Wang, Associate Professor of Aeronautics and Astronautics at MIT will visit the University of Pennsylvania as a Penn Institute for Computational Science (PICS) colloquium speaker. Learn more about the title and topic of his talk below.

QiQi Wang

  • When: Friday, November 9th at 2:00 pm
  • Where: 4th Floor Active Learning classroom at 3401 Walnut Street, Wing A


Finding sensitivity in the long-exposure of chaotic dynamical systems


There are many scientific and engineering applications for the study of how a dynamical system respond to perturbations. When the dynamical system is a computational simulation, these perturbations can be design changes, environmental noise, numerical error, and modeling uncertainties. In this talk, we investigate how a chaotic dynamical system, whose snapshots are extremely sensitive to small perturbations, can have respond smoothly to perturbations in its time-exposure. By time-exposure, we mean long-time-averaged quantities or ensemble-averaged quantities, also known as statistics. We show that many classic concepts and methods for sensitivity and stability analysis do not apply in this study. We then introduce concepts and techniques applicable to chaotic flows, including Lyapunov spectrum analysis and least squares shadowing method. We demonstrate applications of these concepts and technology and illustrate remaining open questions.

Professor Qiqi Wang Bio:

Qiqi Wang got his BS in mathematics from University of Science and Technology at Hefei, China. He then got his Ph.D. in Computational and Mathematical Engineering at Stanford, under the supervision of Parviz Moin and Gianluca Iaccarino. From 2009 to 2015, Qiqi was an assistant professor of Aeronautics and Astronautics at MIT. Since 2015, he has been an associate professor in the same department.


Professor Qiqi Wang Academic Degrees
Ph.D., 2009, Stanford University (Computational and Mathematical Engineering, minor: Aero Astro) M.S., 2008, Stanford University (Computational and Mathematical Engineering) B.S. 2004, University of Science and Technology of China (Mathematics and Applied Mathematics)

Honors and Awards
Grand Prize, Stanford Computer Graphics Rendering Competition, 2007; SIAM Award for Academic Excellence, 2005; Meritorious Award for Mathematical Contest in Modeling, 2003

Society Memberships
American Institute of Aeronautics and Astronautics, Aircraft Owners and Pilots Association, Society for Industrial and Applied Mathematics.

Positions Held at MIT
Assistant Professor, 2009-present

Positions Held outside MIT
Quantitative Analyst, Two Sigma Investments, April 2009 – August 2009; Postdoctoral Scholar, Stanford University, January 2009 – April 2009

Specialization and Research Interests
Engineering design of chaotic dynamical systems, unsteady aerodynamics and turbulence, numerical methods for exascale computation, design optimization of uncertainty.

Teaching Interests
Fluid dynamics, numerical analysis, probabilistic methods

Learn more about PICS events here.