From rjl at amath.washington.edu Mon Oct 5 20:13:24 2009
From: rjl at amath.washington.edu (Randy LeVeque)
Date: Tue Jun 12 13:43:54 2018
Subject: [Amath-seminars] AMath Seminar by Manuel Torrilhon Thursday
Message-ID:
Professor Manuel Torrilhon from ETH-Zurich is visiting the Department of
Applied Mathematics through January, 2010. He will give the Applied Math
Seminar this Thursday at 4pm, details below. Please help welcome him to the
department and hear about his research....
--------------------------------------------------------------------------
Speaker: Manuel Torrilhon, ETH-Zurich (visiting Applied Mathematics)
Title: Modeling in Kinetic Gas Theory: PDE's Meet Statistics
Time: Thursday, October 8, 2009 at 4:00pm
Room: Guggenheim 218
Abstract: Kinetic gas theory describes the flow of gases on the
basis of the statistical distribution of particle velocities. The
governing equation is the Boltzmann equation, a high-dimensional
integro-differential equation. Approximative models for Boltzmann's
equation reduce the complexity of the statistic description by
considering partial differential equations for fluid variables like
density, velocity and temperature. The task is to find statistical
models that provide partial differential equations with desirable
mathematical and physical properties.
From rjl at amath.washington.edu Wed Oct 28 21:10:07 2009
From: rjl at amath.washington.edu (Randy LeVeque)
Date: Tue Jun 12 13:43:54 2018
Subject: [Amath-seminars] Fwd: Seminar of Rich Lehoucq (Thursday -- GUG 218)
In-Reply-To: <03AF09CE-32CF-4722-A3B6-76D38B501645@u.washington.edu>
References: <03AF09CE-32CF-4722-A3B6-76D38B501645@u.washington.edu>
Message-ID:
---------- Forwarded message ----------
From: Ulrich Hetmaniuk
Date: Wed, Oct 28, 2009 at 9:00 PM
Subject: Seminar of Rich Lehoucq (Thursday -- GUG 218)
Dear All,
Here is a friendly reminder that, on Thursday 10/29 at 4pm, Rich
Lehoucq from Sandia National Labs will give a seminar in GUG 218.
Please note the new room GUG 218.
Here are the title and abstract
A NONLOCAL VECTOR CALCULUS WITH APPLICATION TO NONLOCAL BOUNDARY VALUE PROBLEMS
We develop a calculus for nonlocal operators that mimics Gauss'
theorem and the Green's identities of the classical vector calculus.
The operators we treat do not involve the gradient of the scalar
function. We then apply the nonlocal calculus to define variational
formulations of nonlocal "boundary" value problems that mimic the
Dirichlet and Neumann problems for second-order scalar elliptic
partial differential equations. For the nonlocal variational problems,
we derive fundamental solutions, show how one can derive existence and
uniqueness results, and show how, under appropriate limits, they
reduce to their classical analogs.
Best regards,
Ulrich
===================================
Ulrich Hetmaniuk
Assistant Professor
Department of Applied Mathematics
University of Washington
Box 352420
Seattle, WA 98195 - 2420
Telephone: 206 685 9298
http://www.amath.washington.edu/~hetmaniu
===================================
From akb6 at washington.edu Wed Nov 4 10:57:38 2009
From: akb6 at washington.edu (Andrea Barreiro)
Date: Tue Jun 12 13:43:54 2018
Subject: [Amath-seminars] Boeing Seminar: Philip Holmes Nov. 5
Message-ID:
Our second Boeing Distinguished Lecture of the quarter will be
tomorrow, Thursday Nov. 5, at 4:00 pm in 220 Guggenheim.
Please also join us for a reception after the talk on the 4th floor of
Guggenheim.
--------------------------------------------------------------------------------------------------------------------
The neuromechanics of lamprey swimming or,
An elastic rod with a mind of its own
Philip Holmes,
Department of Mechanical and Aerospace Engineering,
Program in Applied Mathematics, and Neuroscience Institute,
Princeton University
Locomotion provides superb examples of cooperation among neuromuscular
systems, environmental reaction forces, and sensory feedback. As part
of a program to understand the neuromechanics of locomotion, here we
construct a model of anguilliform (eel-like) swimming in slender
fishes. Building on a continuum mechanical representation of the body
as an viscoelastic rod, actuated by a traveling wave of preferred
curvature and subject to simplified hydrodynamic reaction forces, we
incorporate a new version of a calcium release and muscle force model,
fitted to data from the lamprey Ichthyomyzon unicuspis, that
interactively generates the curvature wave. We use the model to
investigate the source of the difference in speeds observed between
electromyographic waves of muscle activation and mechanical waves of
body curvature, concluding that it is due to a combination of passive
viscoelastic and geometric properties of the body and active muscle
properties. Moreover, we find that nonlinear force dependence on
muscle length and shortening velocity may reduce the work done by the
swimming muscles in steady swimming.
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From rjl at uw.edu Fri Nov 6 14:58:49 2009
From: rjl at uw.edu (Randy LeVeque)
Date: Tue Jun 12 13:43:54 2018
Subject: [Amath-seminars] AMath Seminar Thursday 11/12
Message-ID:
Contact rjl if you are interested in meeting with the speaker,
he will be here next Thursday and Friday morning...
--------------------------------------------------------------------------
Speaker: Andrew Christlieb, Michigan State University
Title: Parallel Time Integration Based On Integral Deferred Correction.
Time: Thursday, November 12, 2009
Room: Guggenheim 218
Abstract:
In this talk we discuss a class of defect correction methods which
is easily adapted to create parallel time integrators for multi-core
architectures and is ideally suited for developing methods which can
be order adaptive in time. The method is based on Integral Deferred
Correction (IDC), which was itself motivated by Spectral Deferred
Correction by Dutt, Greengard and Rokhlin (BIT-2000).
The method presented here is a revised formulation of explicit IDC, dubbed
Revisionist IDC, which can achieve p^th-order accuracy in '''wall-clock
time'' comparable to a single forward Euler simulation on problems where
the time to evaluate the right-hand side of a system of di erential
equations is greater than latency costs of inter-processor communication,
such as in the case of the N-body problem. The key idea is to re-write
the defect correction framework so that, after initial startup costs,
each correction loop can be lagged behind the previous correction loop in
a manner that facilitates running the predictor and M = p-1 correctors
in parallel on an interval which has K steps, where K>>p. We prove
that given an rth-order Runge-Kutta method in both the prediction and
M correction loops of RIDC, then the method is order rX(M + 1).
The parallelization in Revisionist IDC uses a small number of cores
(the number of processors used is limited by the order one wants to
achieve). Using a four-core CPU, it is natural to think about fourth-order
RIDC built with forward Euler, or eighth-order RIDC constructed with
second order Runge-Kutta. Numerical tests on an N-body simulation show
that RIDC methods can be significantly faster than popular Runge-Kutta
methods such as the classical fourth-order Runge- Kutta scheme.
This is joint work with: Colin Macdonald (Oxford) and Benjamin Ong (MSU)
From rjl at uw.edu Tue Nov 10 09:12:41 2009
From: rjl at uw.edu (Randy LeVeque)
Date: Tue Jun 12 13:43:54 2018
Subject: [Amath-seminars] Re: AMath Seminar Thursday 11/12
In-Reply-To:
References:
Message-ID:
It was just pointed out to me that the seminar announcement below
lacked a time.
It is at 4pm this Thursday.
- rjl
>
> --------------------------------------------------------------------------
>
> Speaker: Andrew Christlieb, Michigan State University
>
> Title: Parallel Time Integration Based On Integral Deferred Correction.
>
> Time: 4pm on Thursday, November 12, 2009
>
> Room: Guggenheim 218
>
> Abstract:
>
> In this talk we discuss a class of defect correction methods which
> is easily adapted to create parallel time integrators for multi-core
> architectures and is ideally suited for developing methods which can
> be order adaptive in time. The method is based on Integral Deferred
> Correction (IDC), which was itself motivated by Spectral Deferred
> Correction by Dutt, Greengard and Rokhlin (BIT-2000).
>
> The method presented here is a revised formulation of explicit IDC, dubbed
> Revisionist IDC, which can achieve p^th-order accuracy in '''wall-clock
> time'' comparable to a single forward Euler simulation on problems where
> the time to evaluate the right-hand side of a system of di erential
> equations is greater than latency costs of inter-processor communication,
> such as in the case of the N-body problem. The key idea is to re-write
> the defect correction framework so that, after initial startup costs,
> each correction loop can be lagged behind the previous correction loop in
> a manner that facilitates running the predictor and M = p-1 correctors
> in parallel on an interval which has K steps, where K>>p. We prove
> that given an rth-order Runge-Kutta method in both the prediction and
> M correction loops of RIDC, then the method is order rX(M + 1).
>
> The parallelization in Revisionist IDC uses a small number of cores
> (the number of processors used is limited by the order one wants to
> achieve). Using a four-core CPU, it is natural to think about fourth-order
> RIDC built with forward Euler, or eighth-order RIDC constructed with
> second order Runge-Kutta. Numerical tests on an N-body simulation show
> that RIDC methods can be significantly faster than popular Runge-Kutta
> methods such as the classical fourth-order Runge- Kutta scheme.
>
> This is joint work with: ?Colin Macdonald (Oxford) and Benjamin Ong (MSU)
>
From akb6 at washington.edu Wed Nov 18 10:02:26 2009
From: akb6 at washington.edu (Andrea Barreiro)
Date: Tue Jun 12 13:43:54 2018
Subject: [Amath-seminars] Boeing Seminar: Jason Fleischer, Nov 19
Message-ID: <5BAEBC4F-E834-483B-B87C-6048710D328B@washington.edu>
Our final Boeing Distinguished Lecture of the quarter will be
tomorrow, Thursday Nov. 19, at 4:00 pm in 220 Guggenheim.
Please also join us for a reception after the talk on the 4th floor of
Guggenheim.
--------------------------------------------------------------------------------------------------------------------
Title: Optical hydrodynamics
Speaker:
Jason Fleischer
Department of Electrical Engineering
Princeton University
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From akb6 at washington.edu Thu Nov 19 08:00:29 2009
From: akb6 at washington.edu (Andrea Barreiro)
Date: Tue Jun 12 13:43:54 2018
Subject: [Amath-seminars] REMINDER: Boeing Seminar: Jason Fleischer, Nov 19
Message-ID:
Our final Boeing Distinguished Lecture of the quarter will be
tomorrow, Thursday Nov. 19, at 4:00 pm in 220 Guggenheim.
Please also join us for a reception after the talk on the 4th floor of
Guggenheim.
--------------------------------------------------------------------------------------------------------------------
Optical hydrodynamics
Jason Fleischer
Department of Electrical Engineering
Princeton University
It is well-known that the basic equations of nonlinear optics can be
mapped to equations from condensed matter physics. For example, the
nonlinear Schr?dinger description of paraxial beam propagation is
identical to the Gross-Pitaevskii treatment of coherent matter waves,
e.g. for Bose-Einstein Condensates. In turn, these equations can be
mapped to Euler-like fluid dynamics using a polar (Madelung)
transformation. Here, we exploit these relations to develop an
optical hydrodynamics. For coherent waves, we examine dispersive
shock wave formation, hydrodynamic instabilities, and vortex flow.
For incoherent waves, we demonstrate all-optical plasma dynamics,
including Landau damping, bump-on-tail instabilities, and weak and
strong regimes of spatial turbulence. Optical experiments are
performed and shown to match very well with theory. The results
establish optical systems as an analog simulator for fluid behavior
and suggest a variety of fluid solutions to photonic problems,
including those of imaging.
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From kutz at amath.washington.edu Thu Dec 3 08:23:46 2009
From: kutz at amath.washington.edu (Nathan Kutz)
Date: Tue Jun 12 13:43:54 2018
Subject: [Amath-seminars] Math Across Campus today
Message-ID:
MathAcrossCampus Lecture: December 3, 4:00-5:00pm in Kane Hall 210
Reception to follow
Title: Estimation and Prediction of Complex Systems:
Progress in Weather and Climate
Speaker: Greg Hakim, University of Washington
Department of Atmospheric Sciences
Abstract:
The use of observations and models to predict the future state of a
system is a hallmark of the scientific method that often has practical
application. As a result, estimation and prediction are central
pursuits across a vast range of disciplines, including the physical,
biological, and social sciences; engineering; and finance. In many
cases the system of interest is composed of a large number of
interacting components that render estimation and prediction
difficult. This challenge motivates this talk in which I will review
essential aspects of, and the basic theory for, estimating and
predicting complex systems. One such system, Earth's atmosphere, will
be used to illustrate techniques that deal with complexity. The
success of these methods for reducing uncertainty in weather forecasts
will be contrasted against a failure to reduce uncertainty in climate-
change forecasts. This contrast motivates a mathematically based
reconsideration of model formulation and calibration for complex
systems.
==============================================================
About the speaker:
Greg Hakim is a leading scientist in the areas of predictability and
atmospheric dynamics. His research interests include hurricanes, past
climates, and polar circulation patterns. Greg is a member of the
American Meteorological Society and the America Geophysical Union. He
serves as Associate Editor for the Journal of the Atmospheric
Sciences, and on the University Corporation for Atmospheric Research's
President's Advisory Committee on University Relations, the American
Meteorological Society's Committee on Atmosphere-Ocean Fluid Dynamics,
and an international expert panel on atmospheric regional modeling and
state estimation (TIGGE-LAM). He has undergraduate degrees in Math and
Atmospheric Sciences, and a PhD in Atmospheric Science from the
University at Albany, State University of NY. After a postdoctoral
fellowship in the Advanced Study Program at the National Center for
Atmospheric Research, Greg joined the Department of Atmospheric
Sciences at the University of Washington in 1999 where he is now
Associate Professor.
===============================================================
http://www.math.washington.edu/mac
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