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IMA Newsletter #412

March 2011

2010-2011 Program

See http://www.ima.umn.edu/2010-2011/ for a full description of the 2010-2011 program on Simulating Our Complex World: Modeling, Computation and Analysis.

News and Notes

2010-2011 IMA Participating Institutions Conferences

IMA Events

IMA Tutorial

Computing and Image Processing with Data Related to Humans and Human Activities

March 5-6, 2011

Organizers: Stacey E. Levine (Duquesne University), Alfio Maria Quarteroni (École Polytechnique Fédérale de Lausanne (EPFL)), Joseph M. Teran (University of California)

IMA Annual Program Year Workshop

Computing in Image Processing, Computer Graphics, Virtual Surgery, and Sports

March 7-11, 2011

Organizers: Stacey E. Levine (Duquesne University), Alfio Maria Quarteroni (École Polytechnique Fédérale de Lausanne (EPFL)), Joseph M. Teran (University of California)

Public Lecture

Jill Pipher: Secrecy, Privacy, and Deception: the Mathematics of Cryptography

March 9, 2011

Speakers: Jill Pipher (Brown University)
Schedule

Tuesday, March 1

10:45am-11:15am Coffee breakLind Hall 400

Wednesday, March 2

10:45am-11:15am Coffee breakLind Hall 400
2:30pm-3:30pm Math 8994: Discontinuous Galerkin methods: An introduction - DG methods for diffusion problemsBernardo Cockburn (University of Minnesota)Lind Hall 305

Thursday, March 3

10:45am-11:15am Coffee breakLind Hall 400
3:30pm-5:30pm Celebration of Donald G. Aronson's retirement and his wide-ranging contributions to the IMA
(Invitation only)
Campus Club Lounge

Friday, March 4

10:45am-11:15am Coffee breakLind Hall 400
1:25pm-2:25pm Using LinkedIn to network your way to a jobDarren Kaltved (University of Minnesota)Keller Hall 3-180 IPS

Saturday, March 5

All Day Morning Chair: Susanne C. Brenner (Louisiana State University)
Afternoon Chair: Simon Masnou (Université Claude-Bernard (Lyon I))
T3.5-6.11
8:30am-9:00am Registration and coffeeLind Hall 400 T3.5-6.11
9:00am-9:15am Welcome to the IMAFadil Santosa (University of Minnesota)Lind Hall 305 T3.5-6.11
9:15am-10:45am Algorithms for variational models involving interfaces in image processing and vision.Selim Esedoglu (University of Michigan)Lind Hall 305 T3.5-6.11
10:45am-11:15am Coffee BreakLind Hall 400 T3.5-6.11
11:15am-12:15pm Algorithms for variational models involving interfaces in image processing and vision (continued)Selim Esedoglu (University of Michigan)Lind Hall 305 T3.5-6.11
12:15pm-2:00pm Lunch T3.5-6.11
2:00pm-3:30pm An introduction to simulation of fluid dynamics with an emphasis on sport applicationsLuca Formaggia (Politecnico di Milano)Lind Hall 305 T3.5-6.11
3:30pm-4:00pm Coffee BreakLind Hall 400 T3.5-6.11
4:00pm-5:00pm An introduction to simulation of fluid dynamics with an emphasis on sport applications (continued)Luca Formaggia (Politecnico di Milano)Lind Hall 305 T3.5-6.11

Sunday, March 6

All Day Chair: John Saunders Steinhoff (University of Tennessee) T3.5-6.11
10:00am-10:30am CoffeeLind Hall 400 T3.5-6.11
10:30am-12:00pm Virtual surgery: real-time simulation of elasticity in biomechanics Joseph M. Teran (University of California, Los Angeles)Lind Hall 305 T3.5-6.11
12:00pm-1:30pm Lunch T3.5-6.11
1:30pm-3:00pm Virtual surgery: real-time simulation of elasticity in biomechanics (continued)Joseph M. Teran (University of California, Los Angeles)Lind Hall 305 T3.5-6.11

Monday, March 7

All Day Morning Chair: Marcelo Bertalmío (Universitat Pompeu Fabra)
Afternoon Chair: Wotao Yin (Rice University)
W3.7-11.11
8:15am-9:15am Registration and coffee Keller Hall 3-176 W3.7-11.11
9:15am-9:30am Welcome to the IMAFadil Santosa (University of Minnesota)Keller Hall 3-180 W3.7-11.11
9:30am-10:30am Numerical models for America's Cup yacht designNicola Parolini (Politecnico di Milano)Keller Hall 3-180 W3.7-11.11
10:30am-11:00am Break Keller Hall 3-176 W3.7-11.11
11:00am-12:00pm Image and Signal Processing using Sparse Optimization, A Few Recent ResultsWotao Yin (Rice University)Keller Hall 3-180 W3.7-11.11
12:00pm-2:00pm Lunch W3.7-11.11
2:00pm-3:00pm Inpainting : a state-of the-artSimon Masnou (Université Claude-Bernard (Lyon I))Keller Hall 3-180 W3.7-11.11
3:00pm-4:00pm Group Discussion Keller Hall 3-180 W3.7-11.11
4:00pm-4:15pm Break Keller Hall 3-176 W3.7-11.11
4:15pm-6:00pm Reception and Poster Session
Poster submissions welcome from all participants
Instructions
Lind Hall 400 W3.7-11.11
An analysis of visual adaptation and contrast perception for Tone Mapping Marcelo Bertalmío (Universitat Pompeu Fabra)
Completely Automated Public Turing test to tell Computers and Humans Apart (CAPTCHA) for transcribing Unicode text from imagesRavi Chityala (University of Minnesota)
Sridevi Pudipeddi (Waldorf College)
Registration of DW-MR Images Using Angular InterpolationJulio Duarte (University of Minnesota)
Guillermo R. Sapiro (University of Minnesota)
Source Identification from Line Integral Measurements and Simple Atmospheric ModelsSelim Esedoglu (University of Michigan)
Brittan Farmer (University of Michigan)
Automatic detection of colon polyps in virtual colonoscopyMarcelo Fiori (University of the Republic)
Pablo Musé (University of the Republic)
Guillermo R. Sapiro (University of Minnesota)
Detecting Small Low Emission Radiating SourcesYulia Hristova (University of Minnesota)
Ramp-preserving Denoising for Conductivity Image Reconstruction in Magnetic Resonance Electrical Impedance Tomography (MREIT)Chang-Ock Lee (Korea Advanced Institute of Science and Technology (KAIST))
Numerical simulation of sailing boats: dynamics and wind-sail fluid-structure interactionMatteo Lombardi (École Polytechnique Fédérale de Lausanne (EPFL))
Nicola Parolini (Politecnico di Milano)
Alfio Maria Quarteroni (École Polytechnique Fédérale de Lausanne (EPFL))
A level set method for evolving spirals by the mean curvature flow with driving forceTakeshi Ohtsuka (Gunma University)
Enabling Surgeons to Create Simulation-Based Teaching ModulesJorg Peters (University of Florida)
Geometry Based Polyp Detection in Wireless Capsule Endoscopy Images Richard Tsai (University of Texas at Austin)
Shape design of facial bone implantsMartin Weiser (Konrad-Zuse-Zentrum für Informationstechnik (ZIB))

Tuesday, March 8

All Day Morning Chair: Luca Formaggia (Politecnico di Milano)
Afternoon Chair: Chiu-Yen Kao (Ohio State University)
W3.7-11.11
8:30am-9:00am Coffee Keller Hall 3-176 W3.7-11.11
9:00am-10:00am A Second Order Virtual Node Algorithm for Poisson Interface Problems on Irregular DomainsJoseph M. Teran (University of California, Los Angeles)Keller Hall 3-180 W3.7-11.11
10:00am-10:30am VirtuaOPs - the idea of web-based virtual surgery on a human 3D model in realtimeThomas Hesse (Orthopädie Solothurn)Keller Hall 3-180 W3.7-11.11
10:30am-11:00am Break Keller Hall 3-176 W3.7-11.11
11:00am-12:00pm New Algorithms in Information Science Stanley J. Osher (University of California, Los Angeles)Keller Hall 3-180 W3.7-11.11
12:00pm-2:00pm Lunch W3.7-11.11
2:00pm-3:00pm Interactive Visualization of Motion DatabasesDaniel F. Keefe (University of Minnesota)Keller Hall 3-180 W3.7-11.11
3:00pm-3:15pm Group photo W3.7-11.11
3:15pm-3:45pm Break Keller Hall 3-176 W3.7-11.11
3:45pm-4:45pm Modeling the cardiovascular system: from imaging clinical applicationsAlfio Maria Quarteroni (École Polytechnique Fédérale de Lausanne (EPFL))Keller Hall 3-180 W3.7-11.11
4:45pm-5:45pm Group DiscussionKeller Hall 3-180 W3.7-11.11

Wednesday, March 9

All Day Morning Chair: Edie Miglio (Politecnico di Milano)
Afternoon Chair: Nicola Parolini (Politecnico di Milano)
W3.7-11.11
8:30am-9:00am CoffeeKeller Hall 3-176 W3.7-11.11
9:00am-10:00am New algorithms for multi-phase flow.Selim Esedoglu (University of Michigan)Keller Hall 3-180 W3.7-11.11
10:00am-11:00am Numerical modelling of competition rowing boatsLuca Formaggia (Politecnico di Milano)Keller Hall 3-180 W3.7-11.11
11:00am-11:30am Break Keller Hall 3-176 W3.7-11.11
11:30am-12:30pm Pictures from piles of dataMichael Gleicher (University of Wisconsin-Madison)Keller Hall 3-180 W3.7-11.11
12:30pm-2:30pm Lunch W3.7-11.11
2:30pm-3:30pm Some advances in development and validation of virtual surgery systemsSuvranu De (Rensselaer Polytechnic Institute)Keller Hall 3-180 W3.7-11.11
3:30pm-3:45pm BreakKeller Hall 3-176 W3.7-11.11
3:45pm-4:45pm Simulating Flows with Strong VorticesJohn Steinhoff (University of Tennessee)Keller Hall 3-180 W3.7-11.11
4:45pm-5:45pm Group DiscussionKeller Hall 3-180 W3.7-11.11
7:00pm-8:00pm IMA Public Lecture: Jill Pipher (Brown University), Secrecy, Privacy, and Deception: The Mathematics of CryptographyWilley Hall 175 W3.7-11.11

Thursday, March 10

All Day Chair: Richard Tsai (University of Texas at Austin) W3.7-11.11
8:30am-9:00am Coffee Keller Hall 3-176 W3.7-11.11
9:00am-10:00am PCA meets GMM and then together meet (once again) sparsityGuillermo R. Sapiro (University of Minnesota)Keller Hall 3-180 W3.7-11.11
10:00am-11:00am Measurement, simulation and visualisation: mathematics and computing in sports engineeringSteve J. Haake (Sheffield Hallam University)Keller Hall 3-180 W3.7-11.11
11:00am-11:30am Break Keller Hall 3-176 W3.7-11.11
11:30am-12:30pm Split Bregman Method for Minimization of Region-Scalable Fitting Energy for Image SegmentationChiu-Yen Kao (Ohio State University)Keller Hall 3-180 W3.7-11.11
12:30pm-2:30pm Lunch W3.7-11.11
2:30pm-3:30pm Numerical assesment of swimsuit performanceEdie Miglio (Politecnico di Milano)Keller Hall 3-180 W3.7-11.11
3:30pm-4:30pm Group DiscussionKeller Hall 3-176 W3.7-11.11
6:00pm-8:30pm Social Event at Stub and HerbsStub and Herbs
227 Oak St Minneapolis, MN 55414
(612) 379-0555
W3.7-11.11

Friday, March 11

All Day Chair: Selim Esedoglu (University of Michigan) W3.7-11.11
8:30am-9:00am Coffee Keller Hall 3-176 W3.7-11.11
9:00am-10:00am Accumulation in photography and videoAntoni Buades (Université de Paris V (René Descartes))Keller Hall 3-180 W3.7-11.11
10:00am-11:00am An algorithm for deformations, collision detection and contact between complex deforming geometry running at hard real-time ratesJernej Barbič (University of Southern California)Keller Hall 3-180 W3.7-11.11
11:00am-11:10am Concluding remarksKeller Hall 3-180 W3.7-11.11

Monday, March 14

10:45am-11:15am Coffee breakLind Hall 400

Tuesday, March 15

10:45am-11:15am Coffee breakLind Hall 400

Wednesday, March 16

10:45am-11:15am Coffee breakLind Hall 400

Thursday, March 17

10:45am-11:15am Coffee breakLind Hall 400

Friday, March 18

All Day University of Minnesota Floating Holiday. The IMA is closed.

Monday, March 21

10:45am-11:15am Coffee breakLind Hall 400

Tuesday, March 22

10:45am-11:15am Coffee breakLind Hall 400
11:15am-12:15pm Reconstruction of binary functions and shapes from incomplete frequency informationYu (David) Mao (University of Minnesota)Lind Hall 305 PS

Wednesday, March 23

10:45am-11:15am Coffee breakLind Hall 400
2:30pm-3:30pm CANCELLED - Math 8994: Discontinuous Galerkin methods: An introduction - Hybridizablemethods: Static condensationBernardo Cockburn (University of Minnesota)Lind Hall 305

Thursday, March 24

10:45am-11:15am Coffee breakLind Hall 400

Friday, March 25

10:45am-11:15am Coffee breakLind Hall 400
1:25pm-2:25pm Design optimization in automotive industry Ren-Jye Yang (Ford)Lind Hall 305 IPS

Monday, March 28

10:45am-11:15am Coffee breakLind Hall 400

Tuesday, March 29

10:45am-11:15am Coffee breakLind Hall 400
11:15am-12:15pm On the use of the finite-fault solution for tsunami generation problemsDimitrios Mitsotakis (University of Minnesota)Lind Hall 305 PS

Wednesday, March 30

10:45am-11:15am Coffee breakLind Hall 400
2:30pm-3:30pm Math 8994: Discontinuous Galerkin methods: An introduction - Hybridizablemethods: Static condensation Bernardo Cockburn (University of Minnesota)Lind Hall 305

Thursday, March 31

10:45am-11:15am Coffee breakLind Hall 400
Abstracts
Jernej Barbič (University of Southern California) An algorithm for deformations, collision detection and contact between complex deforming geometry running at hard real-time rates
Abstract: Fast deformable objects are very useful in robotics applications such as haptic rendering, where high simulation update rates (e.g., 1000 simulation steps per second) are required to maintain device stability. However, in order to simulate two rigid or deformable objects in contact with 6-DoF haptic feedback, it is also necessary to resolve contact between the two objects at haptic rates. With complex **deforming** geometry, this problem is difficult due to very short computation times (e.g., 1 millisec) of each simulation cycle. I will present an algorithm which can perform deformable object simulation, deformable collision detection and contact force and torque computation between two objects, at millisecond simulation rates. The algorithm scales well to both objects having complex geometry, and produces stable contact forces and torques, even at stiffness levels close to haptic device hardware limits.
Marcelo Bertalmío (Universitat Pompeu Fabra) An analysis of visual adaptation and contrast perception for Tone Mapping
Abstract: Joint work with Sira Ferradans, Edoardo Provenzi, and Vicent Caselles.

Tone Mapping is the problem of compressing the range of a High Dynamic Range image so that it can be displayed in a Low Dynamic Range screen, without losing or introducing novel details: the final image should produce in the observer a sensation as close as possible to the perception produced by the real world scene. We propose a tone mapping operator with two stages. The first stage is a global method that implements visual adaptation, based on experiments on human perception, in particular we point out the importance of cone saturation. The second stage performs local contrast enhancement, based on a variational model inspired by color vision phenomenology. We evaluate this method with a metric validated by psychophysical experiments, and in terms of this metric our method compares very well with the state of the art.
Antoni Buades (Université de Paris V (René Descartes)) Accumulation in photography and video
Abstract: The accumulation of photon impacts on a surface is the essence of photography. We will investigate the use of acumulation for both image and video fusion/restoration. Registration and patch based methods will be compared for several applications.
Ravi Chityala (University of Minnesota), Sridevi Pudipeddi (Waldorf College) Completely Automated Public Turing test to tell Computers and Humans Apart (CAPTCHA) for transcribing Unicode text from images
Abstract: Existing image based CAPTCHAs can only transcribe words in an image that contains ASCII characters. In this poster, we are describing a system for transcribing words in an image that contains Unicode characters. Such a system will be useful in transcribing scanned documents from many European languages like Spanish, German, French etc. We will be demonstrating the methods for extracting the individual words from documents using adaptive thresholding, projection and morphological operations. We will also demonstrate a web site for solving the CAPTCHA.
Suvranu De (Rensselaer Polytechnic Institute) Some advances in development and validation of virtual surgery systems
Abstract: Practice is the single most important determinant of a surgeon’s skills. In an effort to significantly improve the trajectory of surgical training, virtual reality (VR) based systems (so-called “surgical simulators”) are being developed to select, train, credential, and retrain physicians, much like flight simulators are used today to train aviation pilots with great success. Such systems, equipped with visual as well as haptic (touch) interfaces, provide an immersive “virtual environment” that enables the trainee to touch, feel, and manipulate virtual tissues and organs through surgical tool handles used in actual surgery, while seeing high-quality images as in real surgery. In this talk we will present some of our recent work in the development and clinical validation of virual surgical systems.
Julio Duarte (University of Minnesota), Guillermo R. Sapiro (University of Minnesota) Registration of DW-MR Images Using Angular Interpolation
Abstract: Joint work with Dr. Christophe Leglent (Radiology Dept, UoM).

Registration of Diffusion-Weighted Magnetic Resonance Images (DW-MRI) is a key step in motion correction, intra and multi-group analysis of brain connectivity, or construction of white matter tracts atlases, among other important tasks. Given the high dimensionality of the data, the registration is usually performed using a single scalar 3D image, which does not optimally represent the full directional information available in the complete diffusion data. Alternatively, tensor-based registration algorithms have been proposed to account for the preferred orientation of diffusion at each voxel. However, tensor-based registration methods impose a diffusion model that might not completely capture the information contained in the raw image. They also depend on the accurate estimation of the tensors, which is known to be sensitive to the Riccian noise, always present in DW-MR images. A new algorithm, based on angular interpolation (AI) of the DW-MRI, has previously been proposed to perform affine registration using the raw DW-MR images, without estimating the diffusion tensors. In this work, we improve and extend this framework and extensively compare it with single volume (using the b0 image) and tensor-based registration techniques. The performance of AI is improved in terms of speed (using kd-trees and parallelism) and accuracy (using sinc interpolation). We show how our technique circumvents the need to re-align the diffusion gradients. We also propose a new algorithm for non-linear registration based on AI and provide a publicly available implementation of the algorithms presented here, extending the FMRIB Software Library (FSL), a well-known open source library for analysis of brain imaging data. Finally, we compare the proposed technique with well known tensor-based registration algorithms such as dti-tk and MedINRIA.
Selim Esedoglu (University of Michigan) New algorithms for multi-phase flow.
Abstract: I will describe joint work with Matt Elsey and Peter Smereka on large scale simulations of mean curvature and related geometric motions for networks of curves in 2D and surfaces in 3D. These motions arise as gradient flow for variational models encountered in image processing (Mumford-Shah model of image segmentation) and materials science (grain boundary motion in polycrystals). Our methods allow simulations with hundreds of thousands of regions, both in 2D and 3D, on uniform grids, achieve good accuracy, and require modest hardware.
Selim Esedoglu (University of Michigan) Algorithms for variational models involving interfaces in image processing and vision.
Abstract: Many of the variational models of image processing and computer vision involve optimizing an energy over interfaces. An important example is image segmentation, where the goal is to partition the image domain into regions containing distinct objects. Typically, the models include a geometric penalty term, such as perimeter or Euler's elastica energy. We will discuss some of the popular algorithms for computing these models, including level set, diffuse interface (phase field), and diffusion generated motion-based approaches. However, the emphasis will be on more recent algorithms that convert some of these notoriously hard, non-convex optimizations to equivalent convex optimization problems.
Selim Esedoglu (University of Michigan), Brittan Farmer (University of Michigan) Source Identification from Line Integral Measurements and Simple Atmospheric Models
Abstract: We consider the problem of estimating the sparse initial condition of a solution to the advection-diffusion equation based on line integrals of the solution at a later time. We propose models for locating single and multiple point sources. We also propose new algorithms for the efficient implementation of these models. In practice, the models are relevant also for reconstructing the solution of the PDE at the observation time from a very sparse Radon transform; in this case, our models improve on more standard Radon inversion techniques by utilizing the specialized information about how the observed function was generated.
Marcelo Fiori (University of the Republic), Pablo Musé (University of the Republic), Guillermo R. Sapiro (University of Minnesota) Automatic detection of colon polyps in virtual colonoscopy
Abstract: Joint work with Sergio Aguirre (Echopixel, USA).

We introduce a CAD algorithm for candidate polyp flagging based on new geometric and texture features. Both the segmentation and classification problems are addressed. The main novelties of this work are the smoothing scheme, which is a surface motion adapted to this application, the incorporation of Haralick texture features, the consideration of the surrounding area for each candidate polyp (we compute context-based features instead of absolute ones), and the strategy of testing regions of multiple sizes. Differential or context-based features are significantly more discriminative than absolute features, as they emphasize local deviations of the geometry and texture over the colon. Testing regions of different sizes allows to precisely delimitate polyps. The proposed algorithm was tested with ground truth data. Results are very promising, detecting 100% of the true-polyps, including flat and small ones, with an average of less than three false positive detections per study.
Luca Formaggia (Politecnico di Milano) An introduction to simulation of fluid dynamics with an emphasis on sport applications
Abstract: Mathematics in sports covers a wide range of aspects, from the study of dynamical systems (to assess biological response to fatigue, for instance), the mechanics of biological tissues (like in injury studies), game theory (for strategy planing), up to the dynamics of fluids and structures to optimise the performance of sport devices (ski, racing boats etc.). In this lectures we focus most on the last topic, giving an introduction to fluid and structural dynamics and fluid-structure interaction problems.
Luca Formaggia (Politecnico di Milano) Numerical modelling of competition rowing boats
Abstract: In this talk we will describe the derivation of mathematical and numerical models for the simulation of high performance rowing boats. Rowing boats are a complex dynamical system strongly affected by the rowers action and movements. Indeed a rowing boat hardly moves with constant speed, but it is instead subject to a complex system of secondary movements: horizontal and vertical accelerations as well as pitching are the main ones. These in turn generate gravity waves which dissipates part of the rowers power.

A numerical model may help a boat manufacturer to foresee the behaviour of new a boat design, and a trainer to better understand how crew composition and rowing style may affect performance. We present the results of several years of collaboration with an important rowing boat manufacturer for the development of a complete mathematical model of the boat dynamics and of its interaction with the free surface flow.
Michael Gleicher (University of Wisconsin-Madison) Pictures from piles of data
Abstract: Most of my work is focused around a single (broad) question: How can we use our understanding of human perception and artistic traditions to improve our tools for communicating and data understanding? In problems ranging from molecular biology to video editing, we are faced with a deluge of data. In this talk, I'll survey some of the ways we've tried to turn this problem into solutions. I'll discuss our efforts in data visualization and multimedia, showing how we can use an understanding of art and perception to create novel tools for a range of problems. I'll also speculate on some of new directions including the use of visual simulation for home healthcare development.
Steve J. Haake (Sheffield Hallam University) Measurement, simulation and visualisation: mathematics and computing in sports engineering
Abstract: The development of new sports equipment, the optimization of performance or the enjoyment of the spectator has been enhanced in recent years through the rapid in computing power. In general, the anlysis of sport requires three things; (1) the experimental measurement of athlete and equipment in 3 dimensions (the reality); (2) mathematical approximation of the motion in the form of analytical or numerical simulation (the analysis); and (3) the visualization of the results in a meaningful way (the virtual reality).

This presentation will describe how mathematics and computing has contributed to the work of sports engineers to allow them to measure the effects of new interventions designed to improve performance. Examples will be given of pragmatic systems to measure the athlete 'in the field' in professional sports such as soccer and tennis, and Olympic sports such as diving and swimming. The use of finite-element analysis and computation fluid dynamics of tennis and cycling will be described as will the integration of their results with analytical models to determine how to improve performance.

The results from experimentation and simulation have used more and more complex graphics as computing power has increased. A glimpse of the future can be had with the use of low-cost 3-dimensional cameras used in devices such as the Kinect controller. Such systems link together the possiblity of performing complex biomechanical on mobile devices with feedback in the virtual world.
Thomas Hesse (Orthopädie Solothurn) VirtuaOPs - the idea of web-based virtual surgery on a human 3D model in realtime
Abstract: No Abstract
Yulia Hristova (University of Minnesota) Detecting Small Low Emission Radiating Sources
Abstract: Joint work with Moritz Allmaras (Texas A&M University), David P. Darrow (University of Texas Medical Branch), Guido Kanschat (Texas A&M University), and Peter Kuchment (Texas A&M University).
Darren Kaltved (University of Minnesota) Using LinkedIn to network your way to a job
Abstract: What do Microsoft, Genentech, Google, Securian, Target, and Ernst & Young have in common? All these companies (and many more) have used LinkedIn to recruit candidates for employment. Kay Luo, Director of Corporate Communications at LinkedIn, explains why, "The main reason that companies are using LinkedIn is to find passive job candidates. Another reason why companies are using LinkedIn, is because referrals from their employees are highly valued because they typically have a higher success/retention rate (hence the popular "employee referral bonuses"). There are members from all 500 of the Fortune 500 companies, and over 83 million LinkedIn members comprise 130 different industries, and include 130,000 recruiters.Your professional network of trusted contacts gives you an advantage in your career, and is one of your most valuable assets. LinkedIn exists to help you make better use of your professional network and help the people you trust in return.This presentation will cover why and how to use LinkedIn to network and search for internships and jobs. Remember — it is more about who you know or need to get to know than what you know!
Chiu-Yen Kao (Ohio State University) Split Bregman Method for Minimization of Region-Scalable Fitting Energy for Image Segmentation
Abstract: In this talk, we introduce the segmentation method which incorporates the global convex segmentation method and the split Bregman technique into the region-scalable fitting energy model. The new proposed method based on the region-scalable model can draw upon intensity information in local regions at a controllable scale, so that it can segment images with intensity inhomogeneity. Furthermore, with the application of the global convex segmentation method and the split Bregman technique, the method is very robust and efficient. By using a non-negative edge detector function to the proposed method, the algorithm can detect the boundaries more easily and achieve results that are very similar to those obtained through the classical geodesic active contour model. Experimental results for synthetic and real images have shown the robustness and efficiency of our method and also demonstrated the desirable advantages of the proposed method.
Daniel F. Keefe (University of Minnesota) Interactive Visualization of Motion Databases
Abstract: Intuitively, one of the best ways to understand motion is to see it, but how can we picture the large multidimensional databases of motion collected today in surgical training or biomechanical studies? In this talk, I will present recent research that begins to address this question through developing novel methods for interactively querying and visualizing motion data. I will describe motivating problems and initial tools developed to support data analysis in two application areas: (1) surgical training, and (2) biomechanical experiments in humans and animals.
Chang-Ock Lee (Korea Advanced Institute of Science and Technology (KAIST)) Ramp-preserving Denoising for Conductivity Image Reconstruction in Magnetic Resonance Electrical Impedance Tomography (MREIT)
Abstract: In MREIT, the harmonic Bz algorithm has been successfully applied to Bz data from phantoms and animals. The algorithm is, however, sensitive to measurement noise in Bz data. In addition, MR signal void in outer l ayers of bones and gas-filled organs, for example, produces salt-pepper noise in MR phase and consequently Bz images. The Bz images typically present areas of sloped transitions, which can be assimilated to ramps. Conductivity contrasts change ramp slopes in Bz images and it is critical to preserve positions of those ramps to correctly recover edges in conductivity images. Here, we propose a ramp-preserving denoising method utilizing a structure tensor. Using an eigenvalue analysis, we identified local regions of salt-pepper noise. Outside the identified local regions, we applied an anisotropic smoothing to reduce noise while preserving their ramp structures. Inside the local regions of salt-pepper noise, we used an isotropic smoothing.
Matteo Lombardi (École Polytechnique Fédérale de Lausanne (EPFL)), Nicola Parolini (Politecnico di Milano), Alfio Maria Quarteroni (École Polytechnique Fédérale de Lausanne (EPFL)) Numerical simulation of sailing boats: dynamics and wind-sail fluid-structure interaction
Abstract: The numerical simulation of free-surface flows around sailing boats is a complex topic that addresses multiple mathematical tasks: the correct study of the flow field around a rigid hull, the numerical simulation of the hull dynamics, the deformation of the sails and appendages under transient external conditions like gusts of wind or wave patterns and, overall, the coupling among all these components. In this work, we present some recent advances that have been achieved in different research topics related to yacht design and performance prediction. In particular, we describe the numerical algorithms that have been developed in the framework of open-source libraries for the simulation of free-surface hydrodynamics and boat dynamics, as well as for the analysis of the fluid-structure interaction between wind and sails. Theoretical and methodological aspects are described and the first preliminary results are reported.
Yu (David) Mao (University of Minnesota) Reconstruction of binary functions and shapes from incomplete frequency information
Abstract: Binary functions are a class of important functions that appears in many applications, e.g. image segmentation, bar code recognition, shape detection and so on. In this research we proved that under certain conditions the binary function can be reconstructed from very limited frequency information by using only simple linear programming. Numerical results and applications will be discussed.
Simon Masnou (Université Claude-Bernard (Lyon I)) Inpainting : a state-of the-art
Abstract: I will survey what has been done in the last years on the inpainting problem, both for still images and video, and give an account of what remains to do.
Edie Miglio (Politecnico di Milano) Numerical assesment of swimsuit performance
Abstract: In this talk we will presents the results concerning different aspects of the performance optimization of a swimsuit. The influence of the sewing on the performance has been analyzed: the results have proved a relevant improvements (in term of drag reduction and course time gain) when sewings are not present on the surface of the swimsuit. We will also analyze the stroke: in order to be able to simulate such kind of phenomena the development of a new set of simulation tools able to treat moving domain problems has been developed. A complete reconstruction of the swimmer kinematics is an extremely complex problem. Even the motion of a single arm is hard to be reproduced accurately without considering complex kinematics: in this respect, we have considered and implemented different stroke kinematics with increasing level of complexity.
Dimitrios Mitsotakis (University of Minnesota) On the use of the finite-fault solution for tsunami generation problems
Abstract: We present a new approach to describe accurately the generation of a tsunami wave due to an underwater earthquake. The main goal of this work is two-fold. First of all, we propose a simple and computationally inexpensive model for the description of the sea bed displacement during an underwater earthquake, based on the finite fault solution for the slip distribution under some assumptions on the dynamics of the rupturing process. Once the bottom motion is reconstructed, we study waves induced on the free surface of the ocean. For this purpose we consider three different models approximating the Euler equations of the water wave theory. Namely, we use the linearized Euler equations (we are in fact solving the Cauchy-Poisson problem), a Boussinesq system and a novel weakly nonlinear model. An intercomparison of these approaches is performed. The developments of the present study are illustrated on the July 27, 2006 Java event, where an underwater earthquake of magnitude 7.7 generated a tsunami that inundated the southern coast of Java.
Takeshi Ohtsuka (Gunma University) A level set method for evolving spirals by the mean curvature flow with driving force
Abstract: This is the brief introduction to the level set formulation for spirals evolving by the geometric flow equation in the plane. Here we consider evolution of spirals with multiple centers and curves. The crucial difficulty is that a spiral does not divide a domain into interior and exterior, and thus the usual level set formulation does not work well. To overcome this difficulty, we consider a curve is on the covering space like as Riemannian surface. For our formulation and equation we obtain the existence and uniqueness of solutions in viscosity sense, and uniqueness of level sets.
Stanley J. Osher (University of California, Los Angeles) New Algorithms in Information Science
Abstract: The past few years have seen an incredible explosion of new (or revival of old) fast and effective algorithms for various imaging and information science applications. These include: nonloca; means, compressive sensing, Bregman iteration, as well as relatively old favorites such as the level set method and PDE based image restoration. I'll give my view of where we are and where we are going.
Nicola Parolini (Politecnico di Milano) Numerical models for America's Cup yacht design
Abstract: In this talk, I will present an overview of the numerical models that have been developed during the last few years for the performance prediction of America's Cup yachts. Different aspects which characterize the behaviour of racing boats will be discussed, such as the role of the yacht appendages, the dynamical response of the yacht in calm and wavy seas and the fluid-structure interaction between wind and sails. A selection of the large scale numerical simulations that were performed to support an America's Cup design team during the last three campaigns will be presented, highlighting the role played by the numerical simulations in the overall yacht design process.
Jorg Peters (University of Florida) Enabling Surgeons to Create Simulation-Based Teaching Modules
Abstract: To broaden the use of simulation for surgical training, in particular of new procedures and of low-volume procedures, we propose an environment and workflow that lets surgeon-educators create the teaching modules. Our challenge is to make the simulation tools accessible, modifiable and sharable by users with moderate computer and VR experience. Our contribution is a workflow that promotes consistency between instructional material and measured criteria; and that makes the authoring process efficient, both for the surgeon, and for computer scientists supporting the simulation environment.
Alfio Maria Quarteroni (École Polytechnique Fédérale de Lausanne (EPFL)) Modeling the cardiovascular system: from imaging clinical applications
Abstract: The role of mathematics in understanding and simulating fluid dynamics and biochemical processes in the physiological and pathological functioning of the human cardiovascular system is becoming more and more crucial. These phenomena are indeed correlated with the origin of some major cardiovascular pathologies, and influence the efficacy of the treatments to heal the arteries from their diseases.

Mathematical models allow the description of the complex fluid-structure interaction which govern the artery wall deformation under the pressure pulse. Moreover, appropriate reduction strategies can be devised to allow for an effective description of the interaction between large, 3D components, and small 1D branches of the circulatory system, as well as the transfer of drugs and chemicals between the arterial lumen and the vessel wall.

This presentation will address some of these issues, the role of medical imaging and their integration in the numerical process as well as in the validation step.
Guillermo R. Sapiro (University of Minnesota) PCA meets GMM and then together meet (once again) sparsity
Abstract: In this talk I will describe recent work with Guoshen Yu and Stephane Mallat on PCA/GMM/structured-sparsity. I will introduce the framework, show state-of-the-art results for image restoration and matrix completion, and present theoretical results regarding compressed sensing of GMM.
John Steinhoff (University of Tennessee) Simulating Flows with Strong Vortices
Abstract: There are many cases where strong vortices shed by parts of a moving body impinge on or come close to other parts of the body that are downwind. These include diverse bodies ranging from aircraft, to race cars to golf balls.

Traditional computation fluid dynamic (CFD) methods solve discretized versions of the governing partial differential equations. In these methods much effort is applied in reducing the local numerical discretization error, such as use of high order discretization schemes or dense computational grids. For thin features, such as shed vortices that propagate over long distances in high Reynolds number flows, this is usually not feasible. Current computers are still not capable of accurately solving the flow equations in these cases.

A relatively new method that is efficient and practical for these problems and that largely overcomes the deficiencies of conventional methods—Vorticity Confinement (VC) —will be described. VC is designed to efficiently capture and convect the important features of flows with thin vortical features without spreading due to numerical diffusion. Effectively, the vortices are treated as multi-dimensional nonlinear discrete solitary waves that “live” on the computational lattice. The basic idea behind VC is similar to shock capturing, where the feature is treated as a weak solution; However, this feature has a structure, which is captured over 2-3 cells on a computational grid with a well defined internal structure, which conserves important quantities such as vorticity and momentum.

Since attached boundary layers are typically also thin vortical regions, Vorticity Confinement can also be used as an implicit no-slip boundary layer model. This implicit boundary layer model thus allows complex bodies to be treated in a simple manner by immersing them in a coarse uniform, Cartesian grid.

Computed shed vortices will be shown for a number of cases, including aircraft, as well as results from blunt body computations ranging from motorcycles to rotorcraft.
Joseph M. Teran (University of California, Los Angeles) Virtual surgery: real-time simulation of elasticity in biomechanics
Abstract: Elasticity plays a fundamental role in many biomechanics and computer graphics related problems. I will talk about numerical methods used for simulating elastic phenomena in soft tissues, skeletal muscles as well as techniques inspired by imaging for determining elastic constitutive models. Specifically, I will discuss common difficulties encountered and my recent algorithm developments to address them. I will put specific emphasis on applications in computer graphics based special effects for virtual characters. Topics include robust resolution of: severe nonlinearity, near incompressibility, extremely large deformation, collision/contact and solid/fluid coupling. I will also discuss the impact of multi-core accelerated computation for such problems and the potentially revolutionary applications it will admit.
Joseph M. Teran (University of California, Los Angeles) A Second Order Virtual Node Algorithm for Poisson Interface Problems on Irregular Domains
Abstract: I will present a second order accurate, geometrically flexible and easy to implement method for solving the variable coefficient Poisson equation with interfacial discontinuities on an irregular domain. We discretize the equations using an embedded approach on a uniform Cartesian grid employing virtual nodes at interfaces and boundaries. A variational method is used to define numerical stencils near these special virtual nodes and a Lagrange multiplier approach is used to enforce jump conditions and Dirichlet boundary conditions. Our combination of these two aspects yields a symmetric positive definite discretization. In the general case, we obtain the standard 5-point stencil away from the interface. For the specific case of interface problems with continuous coefficients, we present a discontinuity removal technique that admits use of the standard 5-point finite difference stencil everywhere in the domain. Numerical experiments indicate second order accuracy in L-infinty.
Richard Tsai (University of Texas at Austin) Geometry Based Polyp Detection in Wireless Capsule Endoscopy Images
Abstract: The problem of detection of colonic polyps in endoscopic images, obtained by a capsule device, is addressed. A procedure, based on geometric features of the input medical image, is proposed and analyzed. It relies on the assumption that the polyps show up as protrusions, and has proven to efficiently detect and single out the colonic polyps. It essentially uses the curvature information of the images, which are interpreted as the graphs of functions defined over the pixel domain. The procedure involves a curvature based identification (using both the Gaussian and mean curvatures) to the graph of the original input image, and subsequently utilizes a predefined threshold to classify the frames with polyps in videos. Numerical experiments on a data-set of wireless capsule endoscopic images and videos are undertaken for evaluation and validation of the proposed approach.
Martin Weiser (Konrad-Zuse-Zentrum für Informationstechnik (ZIB)) Shape design of facial bone implants
Abstract: Joint work with Anton Schiela (Konrad-Zuse-Zentrum für Informationstechnik (ZIB)).

After accidents or inflammations with severe bone traumata, implants are used to restore both functionality and facial appearance of the patients. We consider computing the implant's shape required to match a desired facial shape by optimal control methods. Somewhat surprisingly, the shape optimization problem can be formulated as a quite standard boundary control problem. Function space nonlinear programming algorithms are developed and preliminary numerical results are presented.
Ren-Jye Yang (Ford) Design optimization in automotive industry
Abstract: Automotive industry today is challenged by numerous complex and often conflicting constraints and requirements such as compress vehicle design cycle time, lower the weight and cost of vehicles, and improve product performances, e.g., durability, NVH, safety, quality, reliability, etc. To satisfy these stringent requirements, automobile manufacturers are increasingly relying on Computer-Aided Engineering (CAE) and the use of more formal and structured approaches for product development. Numerical optimization is a systematic tool for considering all disciplines and finds a compromise solution. In addition, as most CAE simulations are computation intensive, special optimization methods and processes are often required. This presentation will focus on historical developments and applications of numerical optimization and robustness methods for vehicle designs. It will address significant technologies, such as Topology Optimization, Multi-disciplinary Design Optimization, Robust, Reliability-Based Design Optimization, and Process Integration and Design Optimization.
Wotao Yin (Rice University) Image and Signal Processing using Sparse Optimization, A Few Recent Results
Abstract: This talk overviews a few viable sparse optimization algorithms such as variable splitting L1/TV minimization, compressive sensing edge detection, nonnegative matrix factorization, and Beta-process based Bayesian learning. They allow us to take advantages of structures in both the model and the data to produce state-of-the-art results.

Imaging examples such as edge detection, image deblurring and denoising, MRI reconstruction, background subtraction, as well as hyperspectral image processing will be given.
Visitors in Residence
Douglas N. Arnold University of Minnesota 9/1/2010 - 6/30/2011
Gerard Michel Awanou Northern Illinois University 9/1/2010 - 6/10/2011
Nusret Balci University of Minnesota 9/1/2009 - 8/31/2011
Jernej Barbič University of Southern California 3/11/2011 - 3/11/2011
Mahdi Bayat University of Minnesota 3/7/2011 - 3/11/2011
Marcelo Bertalmío Universitat Pompeu Fabra 3/6/2011 - 3/12/2011
Susanne C. Brenner Louisiana State University 9/1/2010 - 6/10/2011
Antoni Buades Université de Paris V (René Descartes) 3/5/2011 - 3/11/2011
Pablo Cancela University of the Republic 3/7/2011 - 3/11/2011
Aycil Cesmelioglu University of Minnesota 9/30/2010 - 8/30/2011
Chi Hin Chan University of Minnesota 9/1/2009 - 8/31/2011
Ravi Chityala University of Minnesota 3/7/2011 - 3/11/2011
Bernardo Cockburn University of Minnesota 9/1/2010 - 6/30/2011
Dane Coffey University of Minnesota 3/7/2011 - 3/11/2011
Jintao Cui University of Minnesota 8/31/2010 - 8/30/2011
Vaishali Damle Springer 3/7/2011 - 3/8/2011
Suvranu De Rensselaer Polytechnic Institute 3/8/2011 - 3/10/2011
Laurie Derechin University of Minnesota 3/4/2011 - 3/4/2011
Julio Duarte University of Minnesota 3/7/2011 - 3/11/2011
Selim Esedoglu University of Michigan 1/20/2011 - 6/10/2011
Randy H. Ewoldt University of Minnesota 9/1/2009 - 8/31/2011
Brittan Farmer University of Michigan 3/6/2011 - 3/11/2011
Oscar E. Fernandez University of Minnesota 8/31/2010 - 8/30/2011
Marcelo Fiori University of the Republic 3/7/2011 - 3/11/2011
Luca Formaggia Politecnico di Milano 3/4/2011 - 3/11/2011
Michael Gleicher University of Wisconsin-Madison 3/6/2011 - 3/9/2011
Alvaro Gomez University of the Republic 3/7/2011 - 3/11/2011
Jay Gopalakrishnan University of Florida 9/1/2010 - 6/30/2011
Shiyuan Gu Louisiana State University 9/1/2010 - 6/30/2011
Ren Guo University of Minnesota 3/5/2011 - 3/11/2011
Steve J. Haake Sheffield Hallam University 3/6/2011 - 3/11/2011
Thomas Hesse Orthopädie Solothurn 3/5/2011 - 3/12/2011
Yulia Hristova University of Minnesota 9/1/2010 - 8/31/2011
Christopher Huff University of Central Florida 3/6/2011 - 3/11/2011
Victoria Interrante University of Minnesota 3/7/2011 - 3/11/2011
Darren Kaltved University of Minnesota 3/4/2011 - 3/4/2011
Myungjoo Kang Seoul National University 3/6/2011 - 3/11/2011
Chiu-Yen Kao Ohio State University 3/6/2011 - 3/11/2011
Daniel F. Keefe University of Minnesota 3/7/2011 - 3/11/2011
Markus Keel University of Minnesota 7/21/2008 - 6/30/2011
Sangun Kim Korea Advanced Institute of Science and Technology (KAIST) 3/6/2011 - 3/12/2011
Zhaodan Kong University of Minnesota 3/7/2011 - 3/11/2011
Pawel Konieczny University of Minnesota 9/1/2009 - 8/31/2011
Fedor Korsakov University of Minnesota 3/7/2011 - 3/11/2011
Chang-Ock Lee Korea Advanced Institute of Science and Technology (KAIST) 3/6/2011 - 3/12/2011
Gilad Lerman University of Minnesota 9/1/2010 - 6/30/2011
Stacey E. Levine Duquesne University 3/6/2011 - 3/9/2011
Chaodi Li 3M 3/7/2011 - 3/11/2011
Hengguang Li University of Minnesota 8/16/2010 - 8/15/2011
Zhi (George) Lin University of Minnesota 9/1/2009 - 8/31/2011
Matteo Lombardi École Polytechnique Fédérale de Lausanne (EPFL) 3/6/2011 - 3/11/2011
Mitchell Luskin University of Minnesota 9/1/2010 - 6/30/2011
Kara Lee Maki University of Minnesota 9/1/2009 - 8/31/2011
Yu (David) Mao University of Minnesota 8/31/2010 - 8/30/2011
Simon Masnou Université Claude-Bernard (Lyon I) 3/4/2011 - 3/12/2011
Edie Miglio Politecnico di Milano 3/6/2011 - 3/12/2011
Irina Mitrea University of Minnesota 8/16/2010 - 6/14/2011
Dimitrios Mitsotakis University of Minnesota 10/27/2010 - 8/31/2011
Pablo Musé University of the Republic 3/6/2011 - 3/11/2011
Qihong Nie 3M 3/7/2011 - 3/11/2011
Takeshi Ohtsuka Gunma University 3/5/2011 - 3/18/2011
Alexandra Ortan University of Minnesota 9/16/2010 - 6/15/2011
Cecilia Ortiz-Duenas University of Minnesota 9/1/2009 - 8/31/2011
Stanley J. Osher University of California, Los Angeles 3/8/2011 - 3/10/2011
Katharine Ott University of Kentucky 2/20/2011 - 4/7/2011
Eun-Hee Park Louisiana State University 3/6/2011 - 3/11/2011
Nicola Parolini Politecnico di Milano 3/5/2011 - 3/12/2011
Jorg Peters University of Florida 3/6/2011 - 3/11/2011
Jill Pipher Brown University 3/9/2011 - 3/10/2011
Sridevi Pudipeddi Waldorf College 3/6/2011 - 3/8/2011
Weifeng (Frederick) Qiu University of Minnesota 8/31/2010 - 8/30/2011
Alfio Maria Quarteroni École Polytechnique Fédérale de Lausanne (EPFL) 3/5/2011 - 3/11/2011
Vincent Quenneville-Belair University of Minnesota 9/16/2010 - 6/15/2011
Gregory Jason Randall University of the Republic 3/7/2011 - 3/11/2011
Fernando Reitich University of Minnesota 9/1/2010 - 6/30/2011
Fadil Santosa University of Minnesota 7/1/2008 - 6/30/2011
Guillermo R. Sapiro University of Minnesota 3/7/2011 - 3/11/2011
Shuanglin Shao University of Minnesota 9/1/2009 - 8/31/2011
Eftychios Sifakis University of Wisconsin-Madison 3/6/2011 - 3/9/2011
Pablo Guillermo Sprechmann University of Minnesota 3/7/2011 - 3/11/2011
John Steinhoff University of Tennessee 3/5/2011 - 3/18/2011
Panagiotis Stinis University of Minnesota 9/1/2010 - 6/30/2011
Li-yeng Sung Louisiana State University 9/1/2010 - 6/15/2011
Nicolae Tarfulea Purdue University, Calumet 9/1/2010 - 6/15/2011
Luis Tenorio Colorado School of Mines 3/27/2011 - 6/10/2011
Joseph M. Teran University of California, Los Angeles 3/5/2011 - 3/10/2011
Dimitar Trenev University of Minnesota 9/1/2009 - 8/31/2011
Richard Tsai University of Texas at Austin 3/3/2011 - 5/1/2011
Shawn W Walker Louisiana State University 3/6/2011 - 3/10/2011
Yi Wang University of Minnesota 3/7/2011 - 3/11/2011
Martin Weiser Konrad-Zuse-Zentrum für Informationstechnik (ZIB) 3/6/2011 - 3/11/2011
Lingzhou Xue University of Minnesota 3/5/2011 - 3/11/2011
Ren-Jye Yang Ford 3/24/2011 - 3/25/2011
Wotao Yin Rice University 3/6/2011 - 3/9/2011
Teng Zhang University of Minnesota 3/7/2011 - 3/11/2011
Legend: Postdoc or Industrial Postdoc Long-term Visitor

IMA Affiliates:
Arizona State University, Boeing, Corning Incorporated, ExxonMobil, Ford, General Motors, Georgia Institute of Technology, Honeywell, IBM, Indiana University, Iowa State University, Korea Advanced Institute of Science and Technology (KAIST), Lawrence Livermore National Laboratory, Lockheed Martin, Los Alamos National Laboratory, Medtronic, Michigan State University, Michigan Technological University, Mississippi State University, Northern Illinois University, Ohio State University, Pennsylvania State University, Portland State University, Purdue University, Rice University, Rutgers University, Sandia National Laboratories, Schlumberger Cambridge Research, Schlumberger-Doll, Seoul National University, Siemens, Telcordia, Texas A & M University, University of Central Florida, University of Chicago, University of Delaware, University of Houston, University of Illinois at Urbana-Champaign, University of Iowa, University of Kentucky, University of Maryland, University of Michigan, University of Minnesota, University of Notre Dame, University of Pennsylvania, University of Pittsburgh, University of Tennessee, University of Wisconsin-Madison, University of Wyoming, US Air Force Research Laboratory, Wayne State University, Worcester Polytechnic Institute