Web: http://www.ima.umn.edu | Email: ima-staff@ima.umn.edu | Telephone: (612) 624-6066 | Fax: (612) 626-7370
This month's talks available at http://www.ima.umn.edu/newsletters

IMA Newsletter #342

April 2005

2004-2005 Program

Mathematics of Materials and Macromolecules

See http://www.ima.umn.edu/matter for a full description of the 2004-2005 program on
Mathematics of Materials and Macromolecules: Multiple Scales, Disorder, and Singularities
and http://www.ima.umn.edu/schedule for schedule updates.

News and Notes

2005-2007 IMA postdoctoral fellows

The IMA is pleased to introduce the 2005-2007 postdocs and industrial postdocs. The new postdocs, who will arrive in September, are Evgeniy Bart (Weizmann Institute), Song-Hwa Kwon (Seoul National University), Hstau Liao (City University of New York), Alison Malcolm (Colorado School of Mines), Gloria Haro Ortega (Universitat Pompeu Fabra), Winston Ou (Purdue University ), Tatiana Soleski (Univeristy of Wisconsin–Milwaukee), and Carl Toews (MIT). The new industrial postdocs are Jung-ha An (University of Florida), who will be the fourth IMA industrial postdoc to work with Siemens, Kai Medville (Rutgers University), who will work with the Air Force Research Laboratory, and Xiaoqiang Wang (Pennsylvania State University), who will be the the VA Medical Center's third IMA industrial postdoc. These outstanding young researchers were selected from pools of seventy-two applicants for the regular postdoc positions and fifty-nine industrial postdoc applicants.

Summer 2005 events

The IMA 2005 Summer Program Wireless Communications, June 22-July 1, is designed to meet the challenges posed by the rapid growth in the demand for multimedia wireless services such as voice, data, web-browsing, video, and e-commerce in mobile telephony. Mathematical methods, including stochastic calculus, stochastic approximation, and stochastic control theory, have had a major impact on hybrid communication network models, asynchronous communication networks, CDMA systems, heavy traffic formulation, fluid models, etc. The program, which consists of a three-day tutorial followed by a five-day workshop, will focus on the interplay of the physical, link, and network layers in wireless networks. The objective is to facilitate communication between academia and the industry, and to bridge the mathematical sciences, engineering, and operations research communities.

The Special Workshop Mixed-Integer Programming, July 25-29, will bring together many of the leading researchers in both the theoretical and computational aspects of mixed-integer programming (MIP) to highlight recent advances, foster interaction and collaboration, and to discuss the expansion of the role of MIP in several potential high-impact application areas, such as network design for the Power Grid, computational biology, medical treatment planning, and cryptography. MIP constitutes a unique computational science: it routinely attempts to solve fundamentally intractable problems arising from many applications, and it does so by blending mathematics, ever more sophisticated implementations, and innovative modeling. This workshop is supported in part by the Mathematical Sciences Department of IBM Research and SAS Operations Research & Management Science.

Mathematical Modeling in Industry—A Workshop for Graduate Students, August 1-10, will provide graduate students and qualified advanced undergraduates with first hand experience in industrial research. Students will work in six teams of up to seven students under the guidance of a mentor from industry. The mentor will help guide the students in the modeling process, analysis and computational work associated with a real-world industrial problem. Each team will make a mid-program progress report and an final presentation, and submit a written final report. The deadline for applications for the Mathematical Modeling in Industry workshop is April 15.

The meeting New Directions in Probability Theory, August 5-6, is co-sponsored by the Institute of Mathematical Statistics and the IMA. The meeting, which will be held at the IMA and immediately precedes the Joint Statistical Meetings, August 7-11, is intended for a general probability audience interested in recent developments in probability theory. The topics of the sessions are flows and random media; probability, combinatorics, and statistical mechanics; stochastic integration; stochastic partial differential equations; and random walk in random environments.

Riviére-Fabes Symposium

The School of Mathematics, University of Minnesota, will host the eighth Riviére-Fabes Symposium on Analysis and PDE April 8-10, 2005.

IMA Events

IMA Annual Program Year Workshop

Atomic Motion to Macroscopic Models

April 11-15, 2005

Organizers: Richard D. James (University of Minnesota), Mitchell Luskin (University of Minnesota), John H. Maddocks (Swiss Federal Institute of Technology Lausanne), Christof Schuette (Freie University Berlin)


This workshop will explore new advances and challenges in modeling and computing for materials and macromolecular systems with multiple time and length scales. Topics to be explored include nonequilibrium statistical mechanics, accelerated molecular dynamics, conformation dynamics, kinetic Monte Carlo, rare events, metastability, and spatial averaging.

IMA Workshop

Career Workshop on Minorities and Applied Mathematics

April 22-24, 2005

Organizers: Tepper Gill (Howard University), Ruth Gonzalez (ExxonMobil), Trachette Jackson (Duke University), Steven L. Lee (Lawrence Livermore National Laboratories), Richard Lehoucq (Sandia National Laboratories)


Today, there is a small, but growing, number of under-represented minority mathematicians in academia, government laboratories and industry. The third IMA Career Workshop on Minorities and Applied Mathematics will focus on the problems that confront researchers in the early to mid-career stages of their professional development. The workshop will offer tutorials with practical applications and provide opportunities for networking. A limited number of general interest technical talks will be presented. Senior professionals will provide insight on things they wish someone had told them before they left graduate school, some of the surprises they found upon entering the workplace, and how they managed to overcome the difficulties encountered. These talks are intended to provide an operational and constructive framework for direct interaction and discussion among workshop participants. Small breakout groups will allow for further exploration of ideas, which will then be shared with the entire group. In addition, poster sessions will showcase the work of selected attendees. The workshop will target mathematicians at various stages of their careers, including graduate students, recent PhDs, and early career folks, as well as senior scientists.

Friday, April 1

11:15a-12:15pTelephone-cord instabilities in thin smectic capillariesPaolo Biscari
Politecnico di Milano
Lind Hall 305 MS
1:25p-2:25pIndustrial applications of scene change detection algorithmsMiroslav Trajkovic
Symbol Technologies
Vincent Hall 570 IPS

Monday, April 4

11:15a-12:15pAction minimization and sharp interface limits for the Allen-Cahn equationMaria Reznikoff
New York University
Lind Hall 305 MS

Thursday, April 7

12:20p-1:20pEstimation and Control in Adaptive Optics for Extremely Large TelescopesCurtis R. Vogel
Montana State University
Lind Hall 409 iPAWS

Friday, April 8

1:25p-2:25pA Model for the Oxidative Aging of TiresKevin Ellwood
Ford Motor Company
Vincent Hall 570 IPS
2:45p-3:25pRiviére-Fabes Symposium: Registration and refreshmentMath commons room RFS
3:30p-4:30pDyadic models for the equations of fluid motion Natasa Pavlovic
Princeton University
Vincent Hall 16 RFS
4:45p-5:45pGlobal solutions to special Lagrangian equations Yu Yuan
University of Washington
Vincent Hall 16 RFS

Saturday, April 9

9:00a-9:30aRiviére-Fabes Symposium: Light breakfastMath commons room RFS
9:30a-10:30aUnsolved mysteries of solutions to PDEs near the boundary Vladimir Maz'ya
Ohio State and Linkoeping Universities
Vincent Hall 16 RFS
11:00a-12:00pSome discrete operators arising in harmonic analysis Stephen Wainger
University of Wisconsin
Vincent Hall 16 RFS
1:30p-2:30pThe ten martini problem Svetlana Jitomirskaya
University of California, Irvine
Vincent Hall 16 RFS
3:00p-4:00pMean curvature flow and the isoperimetric problem in the Heisenberg group Luca Capogna
University of Arkansas
Vincent Hall 16 RFS
6:00p-8:00pRiviére-Fabes Symposium dinner RFS

Sunday, April 10

9:00a-9:30aRiviére-Fabes Symposium: Light breakfastMath commons room RFS
9:30a-10:30aSome discrete operators arising in harmonic analysis Stephen Wainger
University of Wisconsin
Vincent Hall 16 RFS
11:00a-12:00pUnsolved mysteries of solutions to PDEs near the boundary - part II Vladimir Maz'ya
Ohio State and Linkoeping Universities
Vincent Hall 16 RFS

Monday, April 11

8:30a-9:15aCoffee and Registration EE/CS 3-176 W4.11-15.05
9:15a-9:30aWelcome and introductionEE/CS 3-180 W4.11-15.05
9:30a-10:30aTransition pathways in complex systemsEric Vanden-Eijnden
New York University
EE/CS 3-180 W4.11-15.05
11:15a-12:15pCalculations of activated trajectories with boundary value formulationRon Elber
Cornell University
EE/CS 3-180 W4.11-15.05
12:15p-2:30pLunch W4.11-15.05
2:30p-3:30pAutomated model reduction for complex molecular systemsChristof Schuette
Freie University Berlin
EE/CS 3-180 W4.11-15.05
3:45p-4:00pGroup Photo W4.11-15.05
4:00p-5:00pIMA Tea and more (with POSTER SESSION)Lind Hall 400 W4.11-15.05
Computing timescales by milestoningRon Elber
Cornell University
Stability and bifurcation of multilattice crystals undergoing martensitic transformationRyan S. Elliott
University of Michigan
Atomistic and Continuum Modeling Strategies for Homoepitaxial Thin Film GrowthJim Evans
Iowa State University
Boundary vortices in thin magnetic filmsMatthias Kurzke
University of Minnesota

Tuesday, April 12

9:00a-9:30aCoffeeEE/CS 3-176 W4.11-15.05
9:30a-10:30aComputer prediction of protein docking and analysis of binding interfacesJulie C. Mitchell
University of Wisconsin
EE/CS 3-180 W4.11-15.05
10:30a-11:15aCoffee EE/CS 3-176 W4.11-15.05
11:15a-12:15pProtein folding: A problem in global optimization Ken A. Dill
University of California - San Francisco
EE/CS 3-180 W4.11-15.05
12:15p-2:30pLunch W4.11-15.05
2:30p-3:30pCauchy-Born rule, generalized Cauchy-Born rule and applications to nanomechanicsWeinan E
Princeton University
EE/CS 3-180 W4.11-15.05

Wednesday, April 13

9:00a-9:30aCoffeeEE/CS 3-176 W4.11-15.05
9:30a-10:30a Modeling fast Hamiltonian chaos by suitable stochastic processesAnja Riegert
Max Planck Institute for the Physics of Complex Sys
EE/CS 3-180 W4.11-15.05
10:30a-11:15aCoffee EE/CS 3-176 W4.11-15.05
11:15a-12:15pMulti-scale modelling of DNAJohn H. Maddocks
Swiss Federal Institute of Technology Lausanne
EE/CS 3-180 W4.11-15.05
12:15p-2:30pLunch W4.11-15.05
2:30p-3:30pMacroscopic equations for microscopic dynamics in periodic crystalsAlexander Mielke
WIAS - Berlin
EE/CS 3-180 W4.11-15.05

Thursday, April 14

9:00a-9:30aCoffeeEE/CS 3-176 W4.11-15.05
9:30a-10:30aTBAGero Friesecke
University of Warwick
EE/CS 3-180 W4.11-15.05
10:30a-11:15aCoffee EE/CS 3-176 W4.11-15.05
11:15a-12:15pAnalysis of a prototypical multiscale method coupling atomistic and continuum mechanicsFrederic Legoll
University of Minnesota
EE/CS 3-180 W4.11-15.05
12:15p-2:30pLunch W4.11-15.05
2:30p-3:30p From atomic scale ordering to mesoscale spatial patterns in surface reactions: Heterogeneous coupled Lattice-Gas (HCLG) simulation approach Jim Evans
Iowa State University
EE/CS 3-180 W4.11-15.05

Friday, April 15

9:00a-9:30aCoffeeEE/CS 3-176 W4.11-15.05
9:30a-10:30aStressed microstructures in M9R-M18R martensitesGiovanni Zanzotto
University of Padua
EE/CS 3-180 W4.11-15.05
10:30a-11:15aCoffee EE/CS 3-176 W4.11-15.05
11:15a-12:15pTBAClaude Le Bris
EE/CS 3-180 W4.11-15.05
12:15p-12:30pClosing remarks EE/CS 3-180 W4.11-15.05

Monday, April 18

11:15a-12:15pNumerical simulation of high dimensional Schroedinger equations and applications to molecular simulationEric Cances
Lind Hall 305 MS

Friday, April 22

1:25p-2:25pTBADavid Trebotich
Lawrence Livermore National Laboratories
Vincent Hall 570 IPS
5:00p-6:30pReception at the IMALind Hall 400 SW4.22-24.05
6:30p-9:00pDinnerMcNamara Alumni Center SW4.22-24.05
8:15p-8:25pWelcoming remarksDouglas N. Arnold
University of Minnesota
McNamara Alumni Center SW4.22-24.05
8:25p-8:55pDinner speakerEarl Barnes
Georgia Institute of Technology
McNamara Alumni Center SW4.22-24.05

Saturday, April 23

8:00a-8:15aCoffee and RegistrationEE/CS 3-176 SW4.22-24.05
8:20a-8:30aIntroductionArnd Scheel
University of Minnesota
EE/CS 3-180 SW4.22-24.05
8:30a-9:15aTBAWilliam A. Massey
Princeton University
EE/CS 3-180 SW4.22-24.05
9:15a-10:00aOptimization in the upstream oil and gas industryCassandra M. McZeal
EE/CS 3-180 SW4.22-24.05
10:00a-10:30aBreakEE/CS 3-176 SW4.22-24.05
10:30a-12:00pPanel discussionRuth Gonzalez   (moderator)
Robert E. Megginson
University of Michigan
Arlie O. Petters
Duke University
Juan Restrepo
University of Arizona
J. Ernest Wilkins Jr.
Clark Atlanta University
EE/CS 3-180 SW4.22-24.05
12:00p-1:30pLunch SW4.22-24.05
1:30p-2:30pBreak-out sessions facilitated by Trachette JacksonEE/CS 3-180 SW4.22-24.05
2:30p-3:00pBreakEE/CS 3-176 SW4.22-24.05
3:00p-4:00pBreak-out reports moderated by Trachette Jackson EE/CS 3-180 SW4.22-24.05
4:00p-5:30p Poster session (selected graduate students)Lind Hall 400 SW4.22-24.05
5:30p-6:30pFree time SW4.22-24.05
6:30p-9:00p DinnerRadisson Metrodome Hotel SW4.22-24.05
7:30p-8:30pA lifetime of diversity: Challenges, successes, and rewardsRichard Tapia
Rice University
Radisson Metrodome Hotel SW4.22-24.05

Sunday, April 24

8:45a-9:00aCoffeeEE/CS 3-176 SW4.22-24.05
9:00a-9:40aComputer productivity tips for your work and researchSteven L. Lee
Lawrence Livermore National Laboratories
EE/CS 3-180 SW4.22-24.05
9:40a-10:10aFunding and your research careerRichard Lehoucq
Sandia National Laboratories
EE/CS 3-180 SW4.22-24.05
10:10a-10:30a Break EE/CS 3-176 SW4.22-24.05
10:30a-11:30aWrap-up discussion - what worked well, what would make it better. Organizing committee, facilitated by Tepper GillEE/CS 3-180 SW4.22-24.05

Friday, April 29

11:15a-12:15pTBAPeter Palffy-Muhoray
Kent State University
Lind Hall 305
1:25p-2:25pTBAHoward Karloff
AT&T Labs - Research
Vincent Hall 570 IPS
Paolo Biscari (Politecnico di Milano) Telephone-cord instabilities in thin smectic capillaries
Abstract: Telephone-cord patterns have been recently observed in smectic liquid crystal capillaries. In this talk we analyse the effects that may induce them. As long as the capillary keeps its linear shape, we show that a nonzero chiral cholesteric pitch favors the SmA*-SmC* transition. However, neither the cholesteric pitch nor the presence of an intrinsic bending stress are able to give rise to a curved capillary shape. The key ingredient for the telephone-cord instability is spontaneous polarization. The free energy minimizer of a spontaneously polarized SmA* is attained on a planar capillary, characterized by a nonzero curvature. More interestingly, in the SmC* phase the combined effect of the molecular tilt and the spontaneous polarization pushes towards a helicoidal capillary shape, with nonzero curvature and torsion.
Ken A. Dill (University of California - San Francisco) Protein folding: A problem in global optimization
Abstract: Joint work with Banu Ozkan, John Chodera, and Thomas Weikl. To compute the folded structure of a protein using a physical model and the monomer sequence has been regarded as a challenge because it involves multiple time and space scales. Our approach has been to understand how proteins physically fold and to try to apply that strategy to protein structure prediction. We believe that proteins break their large global optimization problem into smaller local optimizations. We have been exploring various methods for exploiting that idea for protein structure prediction.
Weinan E (Princeton University) Cauchy-Born rule, generalized Cauchy-Born rule and applications to nanomechanics
Abstract: The focus of this talk is to develop continuum mechanics type of models for studying the deformation of nano-scale objects such as nano-tubes, nano-rods and DNA. The basic tool we will use is various generalizations of the classical Cauchy-Born rule. For this purpose, we will first review the classical Cauchy-Born rule for bulk crystals. We will discuss the validity of the Cauchy-Born rule and give a precise characterization of its boundary of invalidity. We then discuss the generalization of the Cauchy-Born rule to curved low dimensional objects, including the local Cauchy-Born rule and the exponential Cauchy-Born rule. Finally we turn our attention to nano-tubes and nano-rods, and examine whether their deformation can be described by these continuum theories.
Ron Elber (Cornell University) Computing timescales by milestoning
Abstract: An algorithm is presented to compute time scales of complex processes following predetermined milestones along a reaction coordinate. A non-Markovian hopping mechanism is assumed and constructed from underlying microscopic dynamics. General analytical analysis, a pedagogical example, and numerical solutions of the non- Markovian model are presented. No assumption is made in the theoretical derivation on the type of microscopic dynamics along the reaction coordinate. However, the detailed calculations are for Brownian dynamics in which the velocities are uncorrelated in time (but spatial memory remains).
Ryan S. Elliott (University of Michigan) Stability and bifurcation of multilattice crystals undergoing martensitic transformation
Abstract: Understanding thermoelastic martensitic transformations is a fundamental component in the study of shape memory alloys. These transformations involve a hysteretic change in stability of the crystal lattice between an austenite (high symmetry) phase and a martensite (low symmetry) phase within a small temperature range. To study these transformations, a set of phenomenological temperature-dependent atomic pair-potentials is used to derive the crystal's energy density W(F,S_1,S_2,...;T) as a function of a uniform deformation F and a set of internal atomic shift degrees of freedom S_i. Special attention is paid to the evaluation of crystal structure stability. Using a specific set of temperature-dependent pair-potentials a stress-free bifurcation diagram is generated for the B2 binary crystal structure (with temperature serving as the loading parameter). A hysteretic transformation is suggested by the existence of certain stable equilibrium branches corresponding to B2 (CsCl) and B19 (orthorhombic) crystal structures. These results indicate the ability of temperature-dependent atomic potential models to provide valuable insight into the behavior of shape memory alloys such as NiTi, AuCd, and CuAlNi.
Kevin Ellwood (Ford Motor Company) A Model for the Oxidative Aging of Tires
Abstract: A simple kinetic model has been developed to interpret issues related to accelerated aging of tires. The finite-element model is based on the Basic Autoxidation Scheme and incorporates mass transport limitations related to diffusion of oxygen into the layered elastomer system. The effect of aging on transport properties, such as diffusivity, due to changes in cross-link density is also considered in the model. The extent of oxidation is calculated at different locations within the tire as functions of time, temperature, and inflation media. Approximate changes to physical properties were derived from oxidation histories predicted by the model and compared to experimentally measured data which includes crosslink density and elongation-to-break. Finally, we will examine the effect of temperature on accelerated ageing in the context of accelerated testing.
Jim Evans (Iowa State University) From atomic scale ordering to mesoscale spatial patterns in surface reactions: Heterogeneous coupled Lattice-Gas (HCLG) simulation approach
Abstract: Homoepitaxial thin film growth produces a rich variety of far-from-equilibrium morphologies. Atomistic lattice-gas models analyzed by KMC simulation have been most successful to date in predicting behavior observed in specific experiments. However, 2D continuum formulations (level-set, phase-field, geometry-based-simulation = GBS) retaining discrete layers have been explored as alternatives, especially for the regime of highly reversible island formation where KMC becomes inefficient. Exploiting GBS, we present the first precise results for the submonolayer island size distribution in this regime [1]. 3D continuum formulations have been applied to describe multilayer kinetic roughening where step edge barriers inhibit downward transport and produce unstable growth (mound formation). We analyze this phenomonon using realistic atomistic modeling to show that Ag/Ag(100) [regarded as the prototype for smooth growth] actually grows very rough [2]. Furthermore, mound dynamics is seen to be more complex than predicted by standard 3D continuum models. [1] PRB 68 (03) 121401; SIAM MMS 3 (05); [2] PRB 65 (02) 193407.
Matthias Kurzke (University of Minnesota) Boundary vortices in thin magnetic films
Abstract: We analyze a model for thin ferromagnetic films that leads to the formation of vortices at the boundary. The energy asymptotically splits into a singular part depending only on the number of vortices and a finite part depending on their position. This finite part, the renormalized energy, is shown to also control the gradient flow motion associated to the boundary vortex functional. The results and proofs are similar to the theory for Ginzburg-Landau vortices by Bethuel-Brezis-Helein for the static and Sandier-Serfaty for the dynamic case.
Frederic Legoll (University of Minnesota) Analysis of a prototypical multiscale method coupling atomistic and continuum mechanics
Abstract: In order to describe a solid which deforms smoothly in some region, but non smoothly in some other region, many multiscale methods have been recently proposed, that aim at coupling an atomistic model (discrete mechanics) with a macroscopic model (continuum mechanics). We present here a theoretical analysis for such a coupling in a one-dimensional setting. We study both the general case of a convex energy and a specific example of a nonconvex energy, the Lennard-Jones case. In the latter situation, we prove that the discretization needs to account in an adequate way for the coexistence of a discrete model and a continuous one. Otherwise, spurious discretization effects may appear. We also consider the effect of the finite element discretization of the continuum model on the behaviour of the coupled model. This work is joint with Xavier Blanc (Paris 6) and Claude Le Bris (CERMICS, ENPC).
Alexander Mielke (WIAS - Berlin) Macroscopic equations for microscopic dynamics in periodic crystals
Abstract: In infinite periodic lattices the solutions can be studied by Fourier analysis on the associated dual torus. However, in doing a limit procedure with vanishing atomic distance, one observes new phenoma which are usually studied by WKB mehtods. We show that similar results can be obtained under much weaker assumptions by using weak convergence methods. First we show that linearized elastodynamics can be obtained by a gamma limit procedure which automatically produces the effective elastic tensor. Second we study the transport of energy in the lattice which occurs on quite different wave speeds as the macroscopic elastic waves. It is possible to derive a energy transport equation for a Wigner measure which depends on time, space and the wave vector on the dual torus.
Julie C. Mitchell (University of Wisconsin) Computer Prediction of Protein Docking and Analysis of Binding Interfaces
Abstract: Recent work on the development of methods for protein docking and analysis of binding interfaces will be discussed. One of the methods presented is the Docking Mesh Evaluator that uses an implicit solvent model for electrostatics. The Docking Mesh Evaluator is capable of exhaustive search as well as of local and global optimization of binding energies, all of which can be performed using parallel computation. The Fast Atomic Density Evaluator is a method for analyzing protein shape, and shape complementarity within binding interfaces. The Fast Atomic Density Evaluator's complementarity "hot spots" correlate with residues in which mutation is known to impact binding. This has recently been used in the development of engineered ribonucleases able to kill cancer cells. Shape complementarity analysis can also aid docking prediction, either as a post-filter for exhaustive search results or as a means of dynamic parameterization for flexible docking calculations.
Anja Riegert (Max Planck Institute for the Physics of Complex Sys) Modeling fast Hamiltonian chaos by suitable stochastic processes
Abstract: Projection operator techniques known from nonequilibrium statistical mechanics are applied to eliminate fast chaotic degrees of freedom in a low-dimensional Hamiltonian system. A perturbative approach, involving a Markov approximation, yields a Fokker-Planck equation in the slow subspace which respects the conservation of energy. A numerical and analytical analysis of suitable model systems demonstrates the feasibility of obtaining the system specific drift and diffusion terms and the accuracy of the stochastic approximation on all time scales. Non-Markovian and non-Gaussian features of the fast variables are negligible.
Miroslav Trajkovic (Symbol Technologies) Industrial applications of scene change detection algorithms
Abstract: In this presentation I am going to discuss different approaches to scene change detection and its various industrial applications. I will give several examples of different scene change detection algorithms I developed including: motion detection from a moving camera, with application to video surveillance; building background model in the presence of moving objects; detection of the foreground objects with fixed background, and it’s application in automotive industry; and illumination invariant motion detection based on frame differencing; and its application in the bar code reading industry.
Curtis R. Vogel (Montana State University) Estimation and Control in Adaptive Optics for Extremely Large Telescopes
Abstract: Adaptive optics (AO) refers to the real-time correction of wavefront aberrations in an optical imaging system. AO has important applications which range from retinal imaging to high-speed laser communications to astronomy. In astronomical AO, wavefront aberrations are caused by density variations due to differential heating of the air, combined with turbulent mixing. These aberrations are indirectly measured with wavefront sensors and corrected with one or more deformable mirrors. Wavefront reconstruction refers to the control algorithms which map sensor measurements to actuator commands that shape the deformable mirror(s). In this talk we will present an overview of astronomical AO, with an emphasis on wavefront reconstruction. In particular, we will address an interesting limited angle tomography problem, known as atmospheric turbulence tomography, which arises in a particular flavor of AO called multi-conjugate adaptive optics.
Giovanni Zanzotto (University of Padua) Stressed microstructures in M9R-M18R martensites
Abstract: Joint work with Xavier Balandraud (Laboratoire de Mécanique et Ingénieries (LaMI), Institut Français de Mécanique Avancée (IFMA), Université Blaise Pascal (UBP). We revisit the phase transformation that produces monoclinic 'long-period stacking' M9R or M18R martensites in Cu-based shape-memory alloys, and analyze some associated microstructures, in particular a typical wedge-shaped configuration (Fig.). The basic premise is that the cubic-to-monoclinic martensitic phase change in such alloys is, geometrically, a slight modification of the well-known bcc-to-9R transformation occurring for instance in Li and Na, whose basic strain, at the micro level, is the same Bain strain as for the bcc-to-fcc transition. One then determines the 'near-Bain' microstrain variants pertaining to these elements and alloys, and analyze the long-period stacking martensite as a mesoscale 'adaptive phase.' Twins, habit planes, and also more complex microstructures, such as the CuZnAl wedge, can be analyzed in this way. Earlier conclusions that this microstructure is not kinematically compatible at zero stress are confirmed. However, one can check the wedge is `close enough' to compatibility and compute the corresponding stresses, which turn out to be low, causing only minimal plastification and damage in the crystal. This microstructure is therefore rationalized as a viable path for the transformation also in these alloys. One can moreover verify this to be true for all the known lattice parameters reported for materials exhibiting long-period M9R-M18R martensites. The general conclusion is that the observed martensitic microstructures can be stressed to various degrees also in good memory alloys; and that there seem to be no need for material tuning in order tgat such stresses be low. Indeed, the lattice-parameter relations, guaranteeing the zero-stress compatibility of special configurations, favoring the transformation and its reversibility, do not need to be strictly enforced because microstructural stresses are not very sensitive to lattice parameter values.
Visitors in Residence
Jose M. Alamo Iowa State University 4/22/2005 - 4/24/2005
Stuart Antman University of Maryland 3/20/2005 - 4/1/2005
Douglas N. Arnold University of Minnesota 7/15/2001 - 8/31/2006
Donald G. Aronson University of Minnesota 9/1/2002 - 8/31/2005
Marino Arroyo Polytechnic University of Catalunya 4/11/2005 - 5/20/2005
Gerard Awanou University of Minnesota 9/2/2003 - 8/31/2005
Xavier Balandraud Institut Français de Mécanique Avancée (IFMA) 4/22/2005 - 4/30/2005
Earl Barnes Georgia Institute of Technology 4/21/2005 - 4/24/2005
Peter W. Bates Michigan State University 4/24/2005 - 4/27/2005
Patricia Bauman Purdue University 4/10/2005 - 4/23/2005
Paolo Biscari Politecnico di Milano 3/16/2005 - 4/2/2005
Henry A. Boateng University of Michigan 4/22/2005 - 4/24/2005
Albert Boggess Texas A & M University 4/25/2005 - 4/27/2005
Viveka Borum Wayne State University 4/22/2005 - 4/24/2005
LaKeisha Brown East Tennessee State University 4/21/2005 - 4/24/2005
Ron Buckmire Occidental College 4/21/2005 - 4/24/2005
Jean Cadet Stony Brook University 4/22/2005 - 4/24/2005
Maria-Carme Calderer University of Minnesota 9/1/2004 - 6/30/2005
Eric Cances CERMICS 4/6/2005 - 4/26/2005
Tamra Carpenter Telcordia Technologies 4/24/2005 - 4/27/2005
Qianyong Chen University of Minnesota 9/1/2004 - 8/31/2006
Rustum Choksi Simon Fraser University 4/30/2005 - 5/6/2005
Fabrizio Cleri Universita di Perugia 3/20/2005 - 5/23/2005
Carlos Corrales Northern Illinois University 4/21/2005 - 4/24/2005
Ludovica Cecilia Cotta-Ramusino Swiss Federal Institute of Technology at Lausanne (EPFL) 4/10/2005 - 5/10/2005
Antonio DeSimone SISSA-Italy 3/10/2005 - 7/15/2005
Michael Dellnitz University of Paderborn 4/8/2005 - 4/18/2005
Antonio Di Carlo Universita` degli Studi Roma Tre 4/10/2005 - 6/12/2005
Brian DiDonna University of Minnesota 9/1/2004 - 8/31/2006
Brenda Dietrich IBM Corporation 4/25/2005 - 4/27/2005
Ken A. Dill University of California - San Francisco 4/10/2005 - 4/13/2005
Qiang Du Pennsylvania State University 3/26/2005 - 4/1/2005
Qiang Du Pennsylvania State University 4/9/2005 - 4/19/2005
Todd F. Dupont University of Chicago 4/26/2005 - 4/26/2005
Witold Dzwinel AGH University of Mining & Metallurgy 4/1/2005 - 4/30/2005
Weinan E Princeton University 4/10/2005 - 4/15/2005
Kossi Delali Edoh North Carolina A&T State University 4/21/2005 - 4/24/2005
Yalchin Efendiev Texas A & M University 4/10/2005 - 4/17/2005
Ron Elber Cornell University 4/10/2005 - 4/15/2005
Charles M. Elliott University of Sussex 3/20/2005 - 4/8/2005
Ryan S. Elliott University of Michigan 1/1/2005 - 6/30/2005
Kevin Ellwood Ford Motor Company 4/7/2005 - 4/8/2005
Maria Emelianenko Pennsylvania State University 4/11/2005 - 4/15/2005
Bjorn Engquist University of Texas - Austin 4/1/2005 - 4/30/2005
Jim Evans Iowa State University 4/10/2005 - 4/15/2005
Alexander Fischer New York University 4/10/2005 - 4/16/2005
Jose D. Flores University of South Dakota 4/22/2005 - 4/24/2005
Gero Friesecke University of Warwick 4/13/2005 - 4/26/2005
Tim Garoni University of Minnesota 8/25/2003 - 8/31/2005
Eugene C. Gartland Jr. Kent State University 1/10/2005 - 6/30/2005
Tepper Gill Howard University 4/21/2005 - 4/24/2005
Ruth Gonzalez ExxonMobil 4/21/2005 - 4/24/2005
Daniel R. Grayson University of Illinois - Urbana-Champaign 4/25/2005 - 4/27/2005
Robert Gulliver University of Minnesota 9/1/2004 - 6/30/2005
Abba Gumel University of Manitoba 4/22/2005 - 4/24/2005
Amitava Gupta Johnson & Johnson 4/25/2005 - 4/27/2005
Robert C. Hampshire Princeton University 4/21/2005 - 4/24/2005
Chuan-Hsiang Han University of Minnesota 9/1/2004 - 8/31/2005
Lowell Hansen Wayne State University 4/25/2005 - 4/27/2005
Wytrice Harris Wayne State University 4/22/2005 - 4/24/2005
Leesa Maree Heffler Swiss Federal Institute of Technology Lausanne 4/30/2005 - 5/11/2005
Viet Ha Hoang Cambridge University 3/5/2005 - 4/16/2005
David Hoff Indiana University 4/25/2005 - 4/27/2005
Wilhelm Huisinga Free Institute (FU) Berlin 4/7/2005 - 4/15/2005
Monica Jackson Emory University 4/22/2005 - 4/24/2005
Trachette Jackson Duke University 4/22/2005 - 4/24/2005
Richard D. James University of Minnesota 9/1/2004 - 6/30/2005
Robert L. Jerrard University of Toronto 4/25/2005 - 5/25/2005
Shi Jin University of Wisconsin 1/4/2005 - 6/30/2005
Sookyung Joo University of Minnesota 9/1/2004 - 8/31/2006
Chiu Yen Kao University of Minnesota 9/1/2004 - 8/31/2006
Howard Karloff AT&T Labs - Research 4/28/2005 - 4/29/2005
David Kinderlehrer Carnegie Mellon University 4/1/2005 - 6/30/2005
Erica Zimmer Klampfl Ford Motor Company 4/25/2005 - 4/27/2005
Richard Kollar University of Minnesota 9/1/2004 - 8/31/2005
Matthias Kurzke University of Minnesota 9/1/2004 - 8/31/2006
Filip Lankas Swiss Federal Institute of Technology (EPFL) 4/30/2005 - 5/11/2005
Claude Le Bris CERMICS 4/4/2005 - 5/20/2005
Steven L. Lee Lawrence Livermore National Laboratories 4/21/2005 - 4/24/2005
Frederic Legoll University of Minnesota 9/3/2004 - 8/31/2006
Richard Lehoucq Sandia National Laboratories 4/21/2005 - 4/24/2005
Richard Lehoucq Sandia National Laboratories 4/10/2005 - 4/15/2005
Benedict Leimkuhler University of Leicester 2/1/2005 - 6/2/2005
Tony Lelievre University of Montreal 4/10/2005 - 4/16/2005
Stephen Levene University of Texas - Dallas 4/30/2005 - 5/6/2005
Debra Lewis University of Minnesota 7/15/2004 - 8/31/2006
Ren-Cang Li University of Kentucky 4/25/2005 - 4/27/2005
Xiantao Li University of Minnesota 8/3/2004 - 8/31/2006
Chun Liu Pennsylvania State University 9/1/2004 - 6/30/2005
Hailiang Liu Iowa State University 1/1/2005 - 6/30/2005
Roxana Lopez-Cruz Arizona State University 4/22/2005 - 4/25/2005
Mitchell Luskin University of Minnesota 9/1/2004 - 6/30/2005
John H. Maddocks Swiss Federal Institute of Technology Lausanne 4/9/2005 - 5/11/2005
Oluwole Daniel Makinde University of Limpopo 4/21/2005 - 4/27/2005
Juan J. Manfredi University of Pittsburgh 4/25/2005 - 4/27/2005
Samuel P. Marin General Motors 4/26/2005 - 4/27/2005
William A. Massey Princeton University 4/21/2005 - 4/24/2005
Cassandra M. McZeal ExxonMobil 4/22/2005 - 4/24/2005
Robert E. Megginson University of Michigan 4/22/2005 - 4/24/2005
Igor Mezic University of California - Santa Barbara 4/10/2005 - 4/16/2005
Alexander Mielke WIAS - Berlin 4/10/2005 - 4/22/2005
Rick Mifflin ExxonMobil 4/25/2005 - 4/27/2005
Julie C. Mitchell University of Wisconsin 4/1/2005 - 5/31/2005
Jeff Morgan University of Houston 4/25/2005 - 4/27/2005
Roy Nicolaides Carnegie Mellon University 4/25/2005 - 4/27/2005
Norma L. Ortiz Louisiana State University 4/22/2005 - 4/24/2005
Peter Palffy-Muhoray Kent State University 3/27/2005 - 5/25/2005
Jinhae Park University of Minnesota 4/10/2005 - 4/15/2005
Sarah K. Patch General Electric 4/26/2005 - 4/26/2005
Arlie O. Petters Duke University 4/21/2005 - 4/24/2005
Peter Philip University of Minnesota 8/22/2004 - 8/31/2006
Petr Plechac University of Warwick 3/21/2005 - 4/22/2005
Lea Popovic University of Minnesota 9/2/2003 - 8/31/2005
Safraz Rampersaud Wayne State University 4/22/2005 - 4/24/2005
J. Tilak Ratnanather Johns Hopkins University 4/22/2005 - 4/25/2005
Klaus Regenauer-Lieb ETH Hoenggerberg 4/10/2005 - 4/16/2005
Weiqing Ren Princeton University 4/10/2005 - 4/15/2005
Juan Restrepo University of Arizona 4/21/2005 - 4/24/2005
Maria Reznikoff University of Bonn 3/27/2005 - 4/17/2005
Anja Riegert Max Planck Institute for the Physics of Complex Systems 4/4/2005 - 4/28/2005
Joaquin Rivera University of Iowa 4/22/2005 - 4/24/2005
Rolf Ryham Pennsylvania State University 9/1/2004 - 6/30/2005
Tariq Samad Honeywell 4/26/2005 - 4/26/2005
Arnd Scheel University of Minnesota 7/15/2004 - 8/31/2006
Christof Schuette Freie University Berlin 4/10/2005 - 4/16/2005
George R Sell University of Minnesota 9/1/2004 - 6/30/2005
David H. Sharp Los Alamos National Laboratory 4/25/2005 - 4/27/2005
Jie Shen Purdue University 3/22/2005 - 4/2/2005
Tien-Tsan Shieh Indiana University 9/1/2004 - 6/30/2005
Ratnasingham Shivaji Mississippi State University 4/25/2005 - 4/27/2005
Devashish Shrivastava University of Minnesota 4/11/2005 - 4/15/2005
Valery P. Smyshlyaev University of Bath-UK 4/10/2005 - 6/14/2005
Daniel Spirn University of Minnesota 9/1/2004 - 6/30/2005
Andreas Stein University of Wyoming 4/25/2005 - 4/27/2005
Peter J. Sternberg Indiana University 8/15/2004 - 6/15/2005
Vladimir Sverak University of Minnesota 9/1/2004 - 6/30/2005
Richard Tapia Rice University 4/21/2005 - 4/24/2005
Miranda Ijang Teboh-Ewungkem Lafayette College 4/22/2005 - 4/24/2005
David Tello Arizona State University 4/22/2005 - 4/24/2005
Eugene Terentjev Cambridge University 3/13/2005 - 4/30/2005
Luciano Teresi Universita` degli Studi Roma Tre 4/10/2005 - 6/15/2005
Florian Theil University of Warwick 4/4/2005 - 6/11/2005
Miroslav Trajkovic Symbol Technologies 3/31/2005 - 4/3/2005
David Trebotich Lawrence Livermore National Laboratories 4/21/2005 - 4/22/2005
William Tom Trotter Georgia Institute of Technology 4/25/2005 - 4/27/2005
Lev Truskinovsky Ecole Polytechnique, Palaiseau 4/5/2005 - 4/14/2005
Keita Turner Wayne State University 4/22/2005 - 4/24/2005
Anna Vainchtein University of Pittsburgh 4/10/2005 - 4/15/2005
Eric Vanden-Eijnden New York University 4/3/2005 - 4/16/2005
Leticia Velazquez University of Texas - El Paso 4/22/2005 - 4/24/2005
Curtis R. Vogel Montana State University 4/6/2005 - 4/7/2005
Qi Wang Florida State University 1/31/2005 - 5/15/2005
Henry A. Warchall National Science Foundation 4/25/2005 - 4/27/2005
Stephen J. Watson Northwestern University 9/1/2004 - 6/30/2005
Guowei Wei University of Michigan 4/10/2005 - 4/15/2005
Michael Westdickenberg University of Bonn 4/10/2005 - 4/16/2005
Johnson Wetiba Prairie View A&M University 4/22/2005 - 4/24/2005
J. Ernest Wilkins Jr. Clark Atlanta University 4/21/2005 - 4/24/2005
Doug Wright University of Minnesota 2/15/2005 - 8/31/2005
Baisheng Yan Michigan State University 9/1/2004 - 6/30/2005
Aaron Nung Kwan Yip Purdue University 1/16/2005 - 6/30/2005
Aaron Nung Kwan Yip Purdue University 4/25/2005 - 4/26/2005
Emmanuel Yomba University of Ngaoundéré 10/6/2004 - 8/31/2005
Giovanni Zanzotto University of Padua 4/10/2005 - 5/8/2005
Wen Zhang Oak Ridge National Laboratory 4/10/2005 - 4/16/2005
Legend: Postdoc or Industrial Postdoc Long-term Visitor

Participating Institutions: Carnegie Mellon University, Consiglio Nazionale delle Ricerche (CNR), Georgia Institute of Technology, Indiana University, Iowa State University, Kent State University, Lawrence Livermore National Laboratories, Los Alamos National Laboratory, Michigan State University, Minnesota State University Mankato, Mississippi State University, Northern Illinois University, Ohio State University, Pennsylvania State University, Purdue University, Rice University, Sandia National Laboratories, Seoul National University (BK21), Seoul National University (SRCCS), Texas A & M University, University of Chicago, University of Cincinnati, University of Delaware, University of Houston, University of Illinois - Urbana-Champaign, University of Iowa, University of Kentucky, University of Maryland, University of Michigan, University of Minnesota, University of Notre Dame, University of Pittsburgh, University of Texas - Austin, University of Wisconsin, University of Wyoming, Wayne State University
Participating Corporations: 3M, Boeing, Corning, ExxonMobil, Ford Motor Company, General Electric, General Motors, Honeywell, IBM Corporation, Johnson & Johnson, Lockheed Martin, Lucent Technologies, Motorola, Schlumberger-Doll Research, Siemens, Telcordia Technologies