REACTIVE FLOW and TRANSPORT PHENOMENA

Inpainting, the technique of modifying an image in an undetectable form, is as ancient as art itself. The goalsand applications of inpainting are numerous, from the restoration of damaged paintings and photographs to the deletionof selected objects. In this talk, we will introduce a novel algorithm for digital inpainting of still images that attempts2 to replicate the basic techniques used by professional restorators. After the user selects the regions to be restored, thealgorithm automatically fills-in these regions with information surrounding them. The fill-in is done in such a way thatisophote lines arriving at the regions boundaries are completed inside. In contrast with previous approaches, the techniquehere introduced does not require the user to specify where the novel information comes from: this is automatically done,thereby allowing to simultaneously fill-in numerous regions containing completely different structures. The algorithm isvery fast, and in general produces undetectable modifications in the image. Applications of this technique include therestoration of old photographs and damaged film; removal of superimposed text like dates, subtitles, or publicity; and theremoval of entire objects from the image like microphones or wires in special effects. Tuesday, November 2The 10:30 am IMA morning break will be in the IMA West Lounge, Vincent Hall 502IMA Postdoc Seminar:11:00 am Sean C. GarrickUniversity of MinnesotaStochastic Modeling and Simulation of Turbulent React-ing FlowsOrganizer: Javier Armendariz & Henning StruchtrupNOTE: The Postdoc Seminar will be held 15 minutes earlier than usual.The Postdoc Seminar is organized by the IMA postdoctoral members, but all interested IMA participants are encouragedto attend. The Seminar meets in Vincent Hall 570. McKnight Seminar in the Mathematical BiosciencesMeets in the IMA Lecture Hall EE/CS 3-18012:00 pm Tony DeanUniversity of MinnesotaDirty Sex and Single Cells The Case of Necrophilia (TheEvolution of Bacterial Transformation)Abstract: Bacteria are the only organisms known to actively take up DNA and recombine it into their genomes. Whilesuch natural transformation systems may provide many of the same benefits that sexual reproduction provides eukaryotes,there are important differences that critically alter the consequences, especially when recombination’s main benefit isreducing the mutation load. Analytical and numerical methods are used to study the selection of transformation genes inpopulations undergoing deleterious mutation. Selection for transformability depends on the shape of the fitness functionagainst mutation. If the fitness function is linear, then transformation would be selectively neutral were it not for thepossibility that transforming cells may take up DNA that converts them into non-transformable cells. If the selectionincludes strong positive (synergistic) epistasis, then transformation can be advantageous in spite of this risk. The effect oflow quality DNA (from selectively-killed cells) on selection is then studied analytically, and found to impose an additionalcost. The limited data available for real bacterial populations suggest that the conditions necessary for the evolution oftransformation are unlikely to be met, and thus that DNA uptake may have some function other than recombination ofdeleterious mutations.The McKnight Seminar is a joint project of the Graduate School, the Departments of Chemical Engineering & Materi-als Science, Mathematics, and Neuroscience, the Biological Process Technology Institute (BPTI), and the Institute forMathematics and its Applications (IMA). Dynamical Systems Seminar, Vincent Hall 5703:35 pmGeorge R. SellUniversity of MinnesotaInvariant Manifolds and Patterns in the Couette-TaylorFlowAbstract: The main object in this lecture is two-fold. First we will describe the proof of the persistence of normallyhyperbolic invariant manifolds in the finite dimensional setting. Secondly, we will indicate the changes required for proving3 the analogous result in the setting of the Navier-Stokes equations, with the objective of applying this theory to the stabilityof certain patterns which are seen in the Couette-Taylor flow. Wednesday, November 3The 10:30 am IMA morning break will be at the IMA East in Lind Hall 400 12:30–1:30 pmPostdoc Brown Bag SeminarLind Hall 401 An informal seminar run by and for IMA postdocs for the discussion of current research problems. Each week somebodywill give a brief presentation of their work, which will then be discussed by the group. School of Mathematics PDE Seminar in Vincent Hall 2063:35 pmGregory A. SerëginStekhlov Mathematical Institute, St. Pe-tersburgPartial regularity for suitable weak solutions to the Navier-Stokes equations. Thursday, November 4The 10:30 am IMA morning break will be at the IMA East in Lind Hall 400School of Math Applied Mathematics and Numerical Analysis SeminarIMA West Seminar Room, Vincent Hall 57011:15 am Anand GopinathUniversity of MinnesotaTBA See http://www/math.umn.edu/ c̃ockburn/seminar 99-00.html for further information. IMA Tutorial:High-speed CombustionNovember 5, 1999Speakers: John Dold (UMIST)Ashwani K. Kapila (Rensselaer Polytechnic Institute)Mark Short (University of Illinois at Urbana Champaign)D. Scott Stewart (University of Illinois at Urbana Champaign)See also http://www.ima.umn.edu/reactive/fall/t2.html This tutorial will provide an introduction to topics that will be covered in the IMA Workshop on High-speed Combustionin Gaseous and Condensed-phase Energetic Materials, November 8–12, 1999.