Department Colloquium - Adam McCloskey

Jan. 18, 2019

Inference on Winners Many empirical questions can be cast as inference on a parameter selected through optimization. For example, researchers may be interested in the effectiveness of the best policy found in a randomized trial, or the best-performing investment strategy based on historical data. Such settings give rise to a...

APPM Colloquium - Fioralba Cakoni

Dec. 7, 2018

Spectral Problems in Inverse Scattering for Inhomogeneous Media The inverse scattering problem for inhomogeneous (possibly anisotropic) media amounts to solving a nonlinear ill-posed equation, thus presenting difficulties in arriving at a solution. Furthermore, in the case of anisotropic media, the matrix value refractive index may not be uniquely determined from...

APPM Colloquium - MIchael Shearer

Nov. 30, 2018

Granular flow: Particle Size Segregation and New Constitutive Laws The segregation of particles of different sizes can be achieved by vibration or by shear flow. I describe a nonlinear conservation law that captures the main features of segregation under shear flow, such as occurs in an avalanche. Predictions of the...

APPM Colloquium - Fatemeh Pourahmadian

Nov. 16, 2018

Differential imaging of evolution in elastic backgrounds with unknown microstructure Major components of nuclear power plants e.g., reactors, fuel cells and containment vessels are comprised of highly heterogeneous composites that (a) their topology and properties at micro- and meso- scales are uncertain or in most cases unknown, and (b) their...

APPM Colloquium - Nathan Albin

Nov. 9, 2018

Fairest edge usage in spanning trees This talk will explore several interesting and interrelated optimization problems involving the spanning trees of a graph. Each problem will be connected to a single fundamental question: How should we choose a probability distribution on the spanning trees of a graph that treats the...

APPM Colloquium - Shelby Wilson

Nov. 2, 2018

On the dynamics of coupled Morris-Lecar Neurons In recent years, the study of computational neuronal dynamics has made remarkable progress has been made by on the nonlinear study of artificial neural networks. This approach relies on using models of single neurons as building blocks of a much larger network ensemble...

APPM Colloquium - Cristiano Nisoli

Oct. 26, 2018

Designing frustration and topologically constrained disorder in artificial spin ice We are all familiar with classical states of matter as ordered or disordered; and yet some of the most relevant phenomena in nature, from the nano-machinery of life in DNA, to the behavior of animal or human colonies, to the...

APPM Colloquium - Max Gunzburger

Oct. 19, 2018

A Localized Reduced-Order Modeling Approach for PDEs with Bifurcating Solutions Reduced-order modeling (ROM) commonly refers to the construction, based on a few solutions (referred to as snapshots) of an expensive discretized partial differential equation (PDE), and the subsequent application of low-dimensional discretizations of partial differential equations (PDEs) that can be...

APPM Colloquium - Bengt Fornberg

Oct. 12, 2018

Improving the accuracy of the trapezoidal rule The trapezoidal rule uses function values at equispaced nodes. It is very accurate for integrals over periodic intervals, but is usually quite inaccurate in non-periodic cases. Commonly used improvements, such as Simpson’s rule and the Newton-Cotes formulas, are not much (if at all)...

APPM Colloquium - Dan Massey

Oct. 5, 2018

Dan Massey, Interdisciplinary Telecom Program, University of Colorado Boulder Cybersecurity Rule 6: Use Cryptography Correctly This talk explores some of the key mathematical concepts used in cybersecurity. Cryptography is one obvious example where mathematics plays a critical role in cybersecurity. However, this talk is not centered around developing new cryptographic...

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