Colloquium

TBA

03/28/2018 - 4:15pm
03/28/2018 - 5:15pm
Speaker: 
Steven Lion (Emeritus from UMass Dartmouth)
Abstract: 

TBA

Where: 
Freeberg Forum, LC 62, Kravis Center, CMC

TBA

04/04/2018 - 4:15pm
04/04/2018 - 5:15pm
Speaker: 
Matthew Papanikolas (Texas A&M University)
Abstract: 

TBA

Where: 
Freeberg Forum, LC 62, Kravis Center, CMC

TBA

03/21/2018 - 4:15pm
03/21/2018 - 5:15pm
Speaker: 
Thomas Banchoff (Brown University)
Abstract: 

TBA

Where: 
Freeberg Forum, LC 62, Kravis Center, CMC

Unexpected Particle Motions in Viscous Fluids Undergoing Oscillatory Rotation

01/24/2018 - 4:15pm
01/24/2018 - 5:15pm
Speaker: 
Ali Nadim (CGU)
Abstract: 

In this joint work with former doctoral student Shujing "Flora" Xu, we investigate theoretically the effect of the Coriolis force on the motion of a suspended particle in a viscous fluid undergoing rotation. In normal centrifugation, a particle which is denser than the surrounding fluid is "thrown" away from the rotation axis. However, we find that when the rotation is oscillatory, through a combination of viscous drag and the Coriolis force, dense particles may actually migrate toward the rotation axis for certain parameter regimes. We analyze the nonlinear dynamical system describing the particle trajectories using the method of averaging and derive the criterion for such "counter-centrifugation." We also use numerical simulations to verify our predictions. For details, see Xu and Nadim, Physics of Fluids, 28, 021302 (2016).

 

Where: 
Freeberg Forum, LC 62, Kravis Center, CMC

TBA

04/11/2018 - 4:15pm
04/11/2018 - 5:15pm
Speaker: 
Berit N. Givens (Cal State Polytechnic University, Pomona)
Abstract: 

TBA

Where: 
Freeberg Forum, LC 62, Kravis Center, CMC

TBA

02/28/2018 - 4:15pm
02/28/2018 - 5:15pm
Speaker: 
Rochelle Gutierrez (College of Education at Illinois)
Abstract: 

TBA

Where: 
Freeberg Forum, LC 62, Kravis Center, CMC

Irrationality measure functions

01/31/2018 - 4:15pm
01/31/2018 - 5:15pm
Speaker: 
Nikolay Moshchevitin
Abstract: 

We will discuss various problems dealing with approximation of real numbers by rationals.Let $\alpha$ be a real number. A rational fraction  $p/q$ is defined to be a best approximation to $\alpha$ if $ |\alpha q'-p'|> |\alpha q -p|$ for all fractions $p'/q'$ with $ q'<q$. The sequence of the best approximations to $\alpha$  determine the irrationality measure function $\psi_\alpha (t)$ which has nice properties. 

Where: 
Freeberg Forum, LC 62, Kravis Center, CMC

An introduction to image processing, its applications, and the problem of imaging through optical turbulence

11/29/2017 - 4:15pm
11/29/2017 - 5:15pm
Speaker: 
Mario Micheli (HMC)
Abstract: 

In this talk I will give an overview of the exciting and growing field of image processing, by introducing how images and video can be modeled and manipulated mathematically. I will provide examples of the typical problems that are studied in this discipline, and present an array of applications in medicine, astronomy, atmospheric science, security, navigation systems, and others in data science and information technology. Also, I shall present the research problem of image reconstruction under "optical turbulence", i.e. the optical phenomenon caused by light rays being refracted to form distorted images at the observer's location: this typically occurs when looking at objects at a distance in hot climates, or underwater in the presence of temperature gradients (i.e., when the water temperature is not the same at different locations). The results of an imaging recovery algorithm will also be illustrated.

Where: 
Argue Auditorium, Millikan, Pomona College

Exploiting Symmetries in Computations with Lattice Polytopes

12/06/2017 - 4:15pm
12/06/2017 - 5:15pm
Speaker: 
Achill Schürmann(University of Rostock)
Abstract: 
Exploiting symmetry in integer linear programming and lattice
point counting are two difficult problems for which no good general
approach exists. In fact, standard techniques work particularly poor
on symmetric problems. In this talk we give an overview about ongoing
work on new symmetry exploiting techniques for these two fundamental 
problem classes involving lattice polytopes. We in particular present 
some new ideas of decomposing lattice polytopes and give some initial 
proof-of-concept results applying these new techniques.
Where: 
Argue Auditorium, Millikan, Pomona College

Bingo Paradoxes

11/15/2017 - 4:15pm
11/15/2017 - 5:15pm
Speaker: 
Art Benjamin (HMC)
Abstract: 

Imagine you are walking past a crowded Bingo parlor with hundreds of people playing. Suddenly you hear one person excitedly call out "Bingo!". Is it more likely that they have 5 in a row or 5 in a column (or are they the same)? Or is the most probable outcome diagonal? The answers may surprise you.
This is joint work with HMC alums Joseph Kisenwether and Ben Weiss, and Pomona alum Jay Cordes.

Where: 
Argue Auditorium, Millikan, Pomona College
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