This talk investigates the role of feedback in a network of amplifiers. We start by revisiting the theory of the individual feedback amplifier. Then, taking inspiration from neuronal behaviors, we present a simple architecture that makes the network amplification zoomable, allowing for a versatile modulation of the resolution of the network ampl...
Creator:
Sepulchre, Rodolphe (University of Cambridge)
Created:
2015-09-30
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
In this talk, I will discuss some issues and recent results related to the viscous boundary layer theory. In particular, I will present a global existence result on classical soluition to the 2-dimensional unsteady Prandtl's boundary system; some convergence results on viscous solutions when the viscosity becomes small. Both non-slip and Navier-...
Creator:
Xin, Zhouping (Chinese University of Hong Kong)
Created:
2010-02-24
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
For a zero-sum stochastic game which does not satisfy the Isaacs condition, we provide a value function representation for an Isaacs-type equation whose Hamiltonian lies in between the lower and upper Hamiltonians, as a convex combination of the two. For the general case (i.e. the convex combination is time and state dependent) our representatio...
Creator:
Hernandez-Hernandez, Daniel (Center of Investigations in Mathematics (CIMAT))
Created:
2018-05-07
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
In joint work with Carla Savage, we studied the inversion sequence representation of Eulerian polynomials and their generalizations. This led us to new recurrences for the generalized Eulerian polynomials and their refinements. These recurrences, combined with a relaxed notion of interlacing polynomials, called compatible polynomials, can be use...
Creator:
Visontai, Mirkà³ (Google Inc.)
Created:
2014-11-10
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
This lecture will focus on the situation when gradients of the objective function are not available to an optimization algorithm. We summarize algorithms for local optimization of a deterministic function, with particular attention directed to model-based trust-region methods. We provide foundations for the theory underlying these algorithms and...
Creator:
Wild, Stefan (Argonne National Laboratory)
Created:
2016-08-05
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
We discuss properties of distributions that are multivariate totally positive of order two (MTP2). Such distributions appear in the context of positive dependence, ferromagnetism in the Ising model, and various latent models. We show that maximum likelihood estimation for MPT2 exponential families is a convex problem. Hence, if the MLE exists, i...
Creator:
Uhler, Caroline (Massachusetts Institute of Technology)
Created:
2016-01-26
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
The property enhancements associated with dispersion of nanoparticles in polymers will depend not only on the state of dispersion achieved during the synthesis or formulation of the nanocomposite, but also on the degree and direction of particle alignment induced during subsequent processing. Here we present data on flow-induced orientation in t...
Creator:
Burghardt, Wesley R. (Northwestern University)
Created:
2009-09-16
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Ptychography comprises sampling and analyzing the object's spatial spectrogram by windowed (or "short-space") Fourier transforms. Its capability to reconstruct both image and illumination, as well as other experimental conditions including instabilities has proven promising for high-resolution X-ray microscopy. Practical implementation of X-ray ...
Creator:
Menzel, Andreas (Paul Scherrer Institute)
Created:
2017-08-14
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Recent experiments by Kantsler et al. [Phys. Rev. Lett. 99, 178102 (2007)] have shown that the relaxational dynamics of a vesicle in external elongation flow is accompanied by the formation of wrinkles on a membrane. Motivated by these experiments we present a theory describing the dynamics of a wrinkled membrane. The formation of wrinkles is re...
Creator:
Turitsyn, Konstantin (University of Chicago)
Created:
2008-07-23
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
The mechanics of a thin elastic sheet can be explored variationally, by minimizing the sum of 'membrane' and 'bending' energy. For some loading conditions, the minimizer develops increasingly fine-scale wrinkles as the sheet thickness tends to 0. While the optimal wrinkle pattern is probably available only numerically, the qualitative features o...
Creator:
Kohn, Robert V. (New York University)
Created:
2011-05-16
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
It is well known that elastic sheets loaded in tension will wrinkle, with the length scale of wrinkles tending to zero with vanishing thickness of the sheet [Cerda and Mahadevan, Phys. Rev. Lett. 90, 074302 (2003)]. We give the firstmathematically rigorous analysis of such a problem. Since our methods require an explicit understanding of the und...
Creator:
Bella, Peter (New York University)
Created:
2011-05-16
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
This lecture provides an introduction to the IMA Workshop onLarge-scale Inverse Problems and Quantification of Uncertainty. Wepresent context and motivation for the workshop topic along with adiscussion of open research challenges. We will discuss workshop goalsand provide a brief overview of the workshop schedule.
Creator:
Ghattas, Omar (The University of Texas at Austin)
Created:
2011-06-06
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
I'll discuss a method for approximating the super-level set persistent homology of a Gaussian kernel density estimator for a point cloud data set, which is related to the witness complex. Instead of selecting elements of the data set, the witnesses are generated using quadratic programming, and the shifted Voronoi diagram (aka the power diagram)...
Creator:
Carlsson, Erik (University of California, Davis)
Created:
2022-08-02
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Optimization of energy by large aquatic animals (e.g., dolphins, whales, manta) requires adaptations that control hydrodynamic flow to reduce drag, and improve thrust production and efficiency. Although streamlining of the body and appendages minimizes drag, highly derived aquatic animals utilize mechanisms of propulsion and control based on lif...
Creator:
Fish, Frank E. (West Chester University)
Created:
2010-06-05
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
In contrast to the positive definite Helmholtz equation, thedeceivingly similar looking indefinite Helmholtz equation is difficultto solve using classical iterative methods. Applying directly a Krylovmethod to the discretized equations without preconditioning leads ingeneral to stagnation and very large iteration counts. Using classicalincomplet...
Creator:
Gander, Martin J. (Universite de Geneve)
Created:
2010-11-29
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Vacant taxi drivers’ cruising behavior to seek the next potential passenger in a road network generates additional vehicle traveled miles, adding congestion and pollution into the road network and the environment. This study aims to employ reinforcement learning to model idle e-hailing drivers’ optimal sequential decisions in passenger-seeki...
Creator:
Di, Sharon (Columbia University)
Created:
2018-10-05
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
It is now well understood that there is a minimal requirement on the channelquality in feedback stabilization via a communication channel. In the case of SISO plant and SISO channel. This minimal channel quality is given in terms of the degree of instability of the plant to be stabilized. For a MIMO system controlled via a MIMO communication cha...
Creator:
Qiu, Li (Hong Kong University of Science and Technology)
Created:
2015-10-08
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
We develop computational and experimental methods to gain insights into visual functions and psychiatric disorders. We also build deep learning models that predict human behaviors and identify people with disorders. In this talk, I will share our recent innovations on data and models, aiming at understanding and predicting visual attention in na...
Creator:
Zhao, Catherine Qi (University of Minnesota, Twin Cities)
Created:
2017-02-03
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
We explore a geometric and topological approach to understanding the structural significance of edges in a complex network. To do so, we embed the complex network (or the graph $G(V, E)$ representing it) into a Euclidean space determined by the eigen-space of the Moore-Penrose pseudo-inverse of the combinatorial laplacian (denoted by $\bb L^+(G)...
Creator:
Ranjan, Gyan (University of Minnesota, Twin Cities)
Created:
2012-09-07
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Sequential quadratic programming (SQP)methods a powerful and effective class of methods for awide range of nonlinearly constrained optimizationproblems. Given the scope and utility of nonlinearoptimization, it is not surprising that SQP methods arestill a subject of active research. Recentdevelopments in methods for mixed integer nonlinearprogra...
Creator:
Gill, Philip E. (University of California, San Diego)
Created:
2008-11-19
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Cellular structures coarsen according to a local evolution law,a gradient flow or curvature driven growth, for example,limited by space filling constraints, which give rise to randomchanges in configuration. Composed of volumes, facets, theirboundaries, and so forth, they are ensembles of singlularstructures. Among the most challenging and ancie...
Creator:
Kinderlehrer, David (Carnegie Mellon University)
Created:
2008-07-21
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
It has been approximately twenty years since the initial germination ofnumerical continuation as an approach to finding solution points of systemsof polynomial equations and ten years since its flowering into numericalalgebraic geometry, which facilitates description of solution sets of anydimension and operations on these, such as intersection ...
Creator:
Wampler, Charles W. (General Motors Company)
Created:
2006-10-23
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
We study the influence of individual neuronal dynamics and network topology on synchronization of bursting neurons. We demonstrate that the type and duration of bursting are the critical characteristics that determine the synchronization properties of the network. We show that the onset of synchrony in an excitatory-inhibitory network with any c...
Creator:
Belykh, Igor (Georgia State University)
Created:
2012-09-06
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Consider the Vietoris-Rips complex for n evenly-spaced points around a circle. For small choices of the connectivity parameter, this complex is homotopy equivalent to a circle. For n even and for a connectivity parameter slightly less than the diameter of the circle, this complex is the boundary of a cross-polytope and is homeomorphic to the (n/...
Creator:
Adams, Henry (University of Minnesota, Twin Cities)
Created:
2013-10-01
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
The importance of spatial and spatio-temporal data mining is growing with the increasing incidence and importance of large datasets such as trajectories, maps, remote-sensing images, census and geo-social media. Applications include Public Health (e.g. monitoring spread of disease, spatial disparity, food deserts), Public Safety (e.g. crime hot ...
Creator:
Shekhar, Shashi (University of Minnesota, Twin Cities)
Created:
2017-01-24
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
A National Research Council report has called attention tomathematicians the problem of protein folding. Here we will give a settingfor the problem by putting a geometrical structure on the space of proteins.A significant question in the understanding of the folding process is this.Which pairs of positions in a linear string representing the pro...
Creator:
Smale, Stephen (City University of Hong Kong)
Created:
2013-10-09
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
There are many different queueing policies, and they tend to be defined inmodel-specific ways that differ in form from policy to policy. While eachform is suitable for the task at hand (e.g. steady-state derivation,scaling-limit theorem, or proof of some other property), the specificity ofthe policy definition can sometimes limit the scope of wh...
Creator:
Gromoll, Christian (University of Virginia)
Created:
2015-06-26
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Economists have traditionally viewed futures prices as fully informative about future economic activity and asset prices. We argue that open interest could be more informative than futures prices in the presence of hedging demand and limited risk absorption capacity in futures markets. We find that movements in open interest are highly pro-cycli...
Creator:
Yogo, Motohiro (Federal Reserve Bank of Minneapolis)
Created:
2012-05-17
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Microseismic imaging is an important technology for tracking fracture creation and reactivation of pre-existing fractures occurring during various industrial operations, particularly hydraulic fracture treatments of unconventional reservoirs. Often microseismic locations are used to interpret the fracture geometry, although additional insights i...
Creator:
Maxwell, Shawn (Itasca Image)
Created:
2015-05-11
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Two types of wetting phenomena will be discussed: (i) Morphological wettingtransitions at chemically patterned or topographically structured substrates; and(ii) Wetting of flexible membranes such as lipid bilayers by aqueous phases.Morphological wetting transitions between different droplet shapes occur, e.g., as onevaries the amount of liquid d...
Creator:
Lipowsky, Reinhard (Max Planck Institute for Colloids and Interfaces)
Created:
2009-12-07
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
The talk will be based on a joint work with L. Ambrosio, G. Crippa and A.Figalli. First, some new well-posedness results for continuity andtransport equations with weakly differentiable velocity fields will bediscussed. These results can be applied to the analysis of a 2 x 2 systemof conservation laws in one space dimension known as the chromato...
Creator:
Spinolo, Laura Valentina (Scuola Normale Superiore)
Created:
2009-07-25
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
We consider the question of global in time existence and uniqueness of solutions of the infinite depth full water wave problem. We show that the nature of the nonlinearity of the water wave equation is essentially of cubic and higher orders. For any initial data that is small in its kinetic energy and height, we show that the 2-D full water wave...
Creator:
Wu, Sijue (University of Michigan)
Created:
2010-02-23
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Given a model based on a conservation law, we study how the solutiondepends from the initial/boundary datum, from the flow and fromvarious constraints. With this tool, several control problems can beaddressed and the existence of an optimal control can beproved. Models describing escape dynamics of pedestrians, traffic attoll gates, open canals ...
Creator:
Colombo, Rinaldo Mario (Università di Brescia)
Created:
2009-07-31
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
The form of accurate semiclassical surface hopping propagators and wave functions for processes involving more than one electronic quantum state is discussed. It is shown that conditions, which define the required non-classical events along trajectories, can be derived from the Schrödinger equation. These conditions also uniquely specify the dir...
Creator:
Herman, Michael F. (Tulane University)
Created:
2009-01-16
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Despite the rapid decrease in sequencing costs, sequencing a large group of individuals is still prohibitively expensive. Recently, several sophisticated pooling designs were suggested that can identify carriers of rare alleles in large cohorts with a significantly smaller number of lanes, thus dramatically reducing the cost of such large scale ...
Creator:
Golan, David (Tel Aviv University)
Created:
2012-02-15
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Allen Tannenbaum will be speaking on the theme of Optimal Mass Transport for Problems in Systems, Control, and Signal Processing. The lectures will be based on a number of published papers as well as lecture notes. He will lead participants through basic methods in the calculus of variations for the classical solution of the Monge-Kantorovich pr...
Creator:
Rachev, Svetlozar (Zari) (State University of New York, Stony Brook (SUNY)); Tannenbaum, Allen (State University of New York, Stony Brook (SUNY))
Created:
2014-06-09
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Humans have been using weaving to construct baskets, mats, and other two and three-dimensional aspects of the built environment for at least 10,000 years; weaving remains attractive today as a fabrication technique thanks to its cost-effectiveness and the increasing capability of automated looms, with applications in architecture, art, chemical ...
Creator:
Vouga, Etienne (The University of Texas at Austin)
Created:
2019-06-26
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Recently, there has been a rapid rise of on-demand ride-hailing platforms, such as Uber and Didi, which allow passengers with smartphones to submit trip requests and match them to drivers based on their locations and drivers' availability. This increased demand has raised questions about how such a new matching mechanism will affect the efficien...
Creator:
Kong, Guangwen (University of Minnesota, Twin Cities)
Created:
2018-05-16
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
I will talk about a work in collaboration with G. During and C. Josserand on the long-time evolution of waves of a thin elastic plate in the limit of smalldeformation so that modes of oscillations interact weakly. According to thetheory of weak turbulence (successfully applied in the past to plasma, optics, and hydrodynamic waves), this nonlinea...
Creator:
Rica, Sergio (Centre National de la Recherche Scientifique (CNRS))
Created:
2008-07-24
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Joint work with Gil Katz, David Gelman, Mark Ratner and Ronnie Kosloff.Simulation of many body quantum dynamics scales exponentiallybad with the number ofdegrees of freedom. Many methods are devoted to obtain arestricted many body wavefunctionwhich still are able to approximate the quantum dynamics. Inthe context of systembath dynamics the surro...
Creator:
Kosloff, Ronnie (Hebrew University)
Created:
2009-03-03
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
I will present a method to prove weak convergence of numerical methods for dynamical systems, using dual solutions. This general method is applied to optimal control problems, and is used to prove convergence of approximate value functions. The theory of large deviations will also be mentioned. It makes it possible to represent rare event soluti...
Creator:
Sandberg, Mattias (Royal Institute of Technology (KTH))
Created:
2010-10-21
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
The fundamental result of Paouris gives the large deviation estimate for Euclidean norms of log-concave vectors. We extend it to the case of l_r-normsand show that for r>=2, p>=1 the p-th moment of the l_r-norm of a log-concave random vector is comparable to the sum of the first moment and the weak p-th moment up to a constant proportional to r....
Creator:
Latala, Rafal (University of Warsaw)
Created:
2015-04-14
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
In 1993 V. Scheffer produced a nontrivial weak solution of the 2D incompressible Euler equationswith compact support in space-time. Subsequently A.Shnirelman gave different constructionsfor solutions with (i) compact support in time and (ii) strictly decreasing energy. Such 'wild' solutionsseemingly contradict the idea of an evolution equation. ...
Creator:
Székelyhidi, Là¡szlà³ Jr. (Rheinische Friedrich-Wilhelms-Universität Bonn)
Created:
2010-02-26
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Phytoplankton floating in the ocean, sperm moving through the reproductive tract, and fish swimming in the sea all rely on an intricate interplay of forces. These are examples of how flexible structures interact with a surrounding fluid €“ a common theme in biological fluid dynamics. This lecture will explore how mathematical models and computat...
Creator:
Fauci, Lisa J. (Tulane University)
Created:
2015-03-11
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
In this lecture we shall present a survey of recent work on several topics related with numerical approximation of waves.Control Theory is by now and old subject, ubiquitous in many areas of Science and Technology. There is a quite well-established finite-dimensional theory and many progresses have been done also in the context of PDE (Partial D...
Creator:
Zuazua, Enrique (Basque Center for Applied Mathematics)
Created:
2009-03-04
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
We study wave motion in a lattice differential equation, specifically, in a spatially discrete Allen-Cahn equation with a bistable nonlinearity. The system may, but need not, be near the continuum limit. Superimposed on the regular (periodic) lattice is a spatial variation which varies in an arbitrary (generally non-periodic) fashion; it can eit...
Creator:
Mallet-Paret, John (Brown University)
Created:
2012-10-22
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
In this talk, we shall survey some recent results on the wave propagation inthe two species competition systems with Lotka-Volterra type nonlinearity. This includes systems with continuous and discrete diffusion.Both monostable and bistable cases shall be discussed.Questions on minimal wave speed for the monostable case,propagation failure in th...
Creator:
Guo, Jong-Sheng (Tamkang University)
Created:
2012-12-03
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Wave propagation in optical lattices with honeycomb background, termed Photonic Graphene, is investigated. A tight binding approximation leads to a coupled mode system. In bulk media a nonlinear Dirac type system is obtained which describes conical, elliptical and straight-line diffraction. With rapidly varying helical waveguides linear and nonl...
Creator:
Ablowitz, Mark J. (University of Colorado)
Created:
2016-10-31
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
We analyze long range wave propagation in three-dimensional randomwaveguides. The waves are trapped by top and bottom boundaries, butthe medium is unbounded in the two remaining directions. We considerscalar waves, and motivated by applications in underwater acoustics,we take a pressure release boundary condition at the top surface anda rigid bo...
Creator:
Borcea, Liliana (Rice University)
Created:
2013-01-16
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Measured bioresponses are often characterized byan intrinsic high frequency and strong persistent correlationsinhibiting statistical modeling by the traditional techniques.The talk overviews two novel wavelet-based techniquesfor modeling such challenging data.Wavelet domains provide natural modelingenvironments for data that scale, as well as fo...
Creator:
Vidakovic, Brani (Georgia Institute of Technology)
Created:
2005-12-08
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
After separating the electronic end nuclear coordinates through the Born-Oppenheimer approximation, one may attempt to solve the electronic Schrodinger equation by a hierarchy of wave function techniques. The lowest level in this hierarchy and the core method of the wave function quantum chemistry is the Hartree-Fock (HF) model, in which each el...
Creator:
Slipchenko, Lyudmila V. (Iowa State University)
Created:
2008-09-26
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Photonic crystals and Metamaterials are made from assemblies of multiple elements usually arranged in repeating patterns at scales of the order or smaller than the wavelengths of the phenomena they influence. Because time and space play a similar role in wave propagation, wave propagation is affected by spatial modulation or by time modulation o...
Creator:
Fink, Mathias (École Supérieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI))
Created:
2017-03-13
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
A new form of coherent optical microscopy is described thatgenerates images (reconstructions) of two and three-dimensional,penetrable scatteringobjects computationally from sets of measured digital hologramsof scattered field data collected in a suite of scatteringexperiments. Themicroscope uses the technique of 'phase shifting holography'(expla...
Creator:
Devaney, Anthony J. (Northeastern University)
Created:
2005-10-21
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Day 4: Transport theory leads to a natural metric of the space of probability densities that in turn leads to a natural Riemannian structure. We will describe some of the basic geometric concepts such as Ricci curvature, and see how this methodology allows one to define a notion of curvature on rather general metric spaces. We will describe appl...
Creator:
Tannenbaum, Allen (State University of New York, Stony Brook (SUNY))
Created:
2014-06-12
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Discretized Langevin diffusions are efficient Monte Carlo methods for sampling from high dimensional target densities that are log-Lipschitz-smooth and (strongly) log-concave. In particular, the Euclidean Langevin Monte Carlo sampling algorithm has received much attention lately, leading to a detailed understanding of its non-asymptotic converge...
One of the most characteristic features of turbulence in three-dimensional incompressible fluids is enhanced energy dissipation.Most attempts to explain this phenomenon appeal to the remarkable Lagrangian properties of vorticity for inviscid flows. I review some of the ideas that have been proposed, including vortex stretching, vortexreconnectio...
Creator:
Eyink, Gregory L. (Johns Hopkins University)
Created:
2010-02-21
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Abstract: Over the past period of a decade and more, mathematicians in the PDE community have developed techniques for the phase space analysis of the dynamics of many model nonlinear Hamiltonian PDEs. These results include constructions of KAM invariant tori, Birkhoff normal forms and Nekhoroshev stability theorems, and constructions of cascade...
Creator:
Craig, Walter (McMaster University)
Created:
2012-09-24
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Action potentials are the packets of communication in the nervous system. The voltage dependent sodium and potassium channels are the crucial players in the initiation and propagation of the action potential. Voltage sensing in these channels is mediated by the movement of intrinsic charges of the channel proteins in response to changes in the e...
Creator:
Bezanilla, Francisco (University of Chicago)
Created:
2015-07-21
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
To understand the interactions between entities (for example, people, objects or groups) systems of interactions can be modeled as graphs linking nodes (entities) with edges that represent various types of connections between the entities. After data collection there are many statistical approaches to analyzing the data, but our approach is to m...
Creator:
Dean, Nathaniel (Texas State University-San Marcos)
Created:
2010-03-27
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
This talk will introduce the Rank Invariant Visualization and Exploration Tool (RIVET). The first available software for two-parameter persistent homology, RIVET allows for the computation and visualization of both the bigraded Betti numbers and the rank invariant of two-dimensional persistence modules. The talk will demonstrate RIVET and explai...
Creator:
Wright, Matthew (St. Olaf College)
Created:
2018-08-14
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
The rapid improvements in computational power have enabled researchers to produce large amounts of molecular simulation data. Hence there is a pressing need to be able to analyze such data to enhance our understanding of molecular dynamics. However, given their massive size and typically high-dimensionality, it is hard to directly traverse and e...
Creator:
Wang, Yusu (The Ohio State University)
Created:
2013-12-09
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Given a graph between N high-dimensional nodes, can we faithfully visualize it in just a few dimensions? We present an algorithm that improves the state-of-the art in dimensionality reduction by extending the Maximum Variance Unfolding method. Visualizations are shown for social networks, species trees, image datasets and human activity.If we ar...
Creator:
Jebara, Tony (Columbia University)
Created:
2008-10-29
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Joint work with H. Kim and T. Funada.The problem of radial fingering in two phase gas/liquid flow ina Hele-Shaw cell under injection or withdrawal is studied here.The problem is analyzed as a viscous potential flow VPF inwhich the potential flow analysis of Paterson 1981 and othersis augmented to account for the effects of viscosity on thenormal...
Creator:
Joseph, Daniel D. (University of Minnesota, Twin Cities)
Created:
2008-07-14
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
I will present an hydrodynamic model for the motility of keratocytes orfibroblasts on substrates in vitro. Cells or fragment of cells have beenobserved to switch from a stationary round state to a motile andanisotropic crescent-shaped state. Experimentally, a polarization of theactin network occurs in a preferred direction prior to motility andd...
Creator:
Ben Amar, Martine (École Normale Supérieure)
Created:
2009-03-23
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Master equation is a powerful tool for studying McKean-Vlasov dynamics where the distribution of the state process enters the coefficients directly, with particular applications including mean field games and stochastic control problems with partial information. In this talk we propose an intrinsic notion of viscosity solution for parabolic mast...
Creator:
Zhang, Jianfeng (University of Southern California)
Created:
2018-06-13
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
We discuss bacterial biofilms and the scope for describing their viscoelastic mechanical properties as a consequence of their underlying polymeric and multiphase morphology. Biofilms are the most prevalent phenotype of bacteria in nature. Biofilms form under conditions common in industry and in the body. They are structurally heterogeneous on mu...
Creator:
Solomon, Michael J. (University of Michigan)
Created:
2009-09-15
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
In an effort to efficiently manufacture quality products, numerical models and empirical measurements are used to predict (virtually) the performance of a hearing aid. Finite element analysis is used to study multi-physics processes such as thermo-mechanically induced stress due to heat flow from soldering, acoustic and structural interactions d...
Creator:
Burns, Thomas H. (Starkey Laboratories)
Created:
2008-10-17
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
A major transition in the operation of electric power grids is the replacement of bulk generation based on synchronous machines by distributed generation based on low-inertia power electronic sources. The accompanying "loss of rotational inertia" and the fluctuations by renewable sources jeopardize the system stability, as testified by the ever-...
Creator:
Dorfler, Florian (ETH Zürich)
Created:
2016-05-12
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
The talk will review the Virtual Element spaces, recently introduced by the speaker and co-authors in order to approximate spaces of the type H(div) or H(curl) on polygonal and polyhedral decompositions. As is well known, these spaces are needed in the approximation of boundary value problems for (systems of) Partial Differential Equations in mi...
Creator:
Brezzi, Franco (Istituto Universitario di Studi Superiori)
Created:
2014-10-24
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
We present and analyse a family of approximations of magneto-static problems based on the Virtual Element approach in two and three dimensions. The magnetic field H is discretized as an edge Virtual Element, and the (given) current density is interpolated as a face Virtual Element. The constitutive equation is imposed strongly, and the condition...
Creator:
Marini, Donatella (Università di Pavia)
Created:
2017-07-01
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
We apply the Virtual Element approach for the discretization of advection-diffusion-reaction problems with variable coefficients on polygonal grids. We analyze both the primal and the mixed formulation, and prove optimal convergence results in H1 and in L2. We provide numerical tests confirming the theoretical results.
Creator:
Marini, Donatella (Università di Pavia)
Created:
2014-10-24
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
The virial theorem is a nice property for the linear Schrödinger equation in atomic and molecular physics as it gives an elegant ratio between the kinetic and potential energies and is useful in assessing the quality of numerically computed eigenvalues. If the governing equation is a nonlinear Schr\"{o}dinger equation with power-law nonlinearity...
Creator:
Lin, Tai-Chia (National Taiwan University)
Created:
2016-11-07
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Image-based rendering has been one of the hottest areas in computergraphics in recent years. Instead of using CAD and painting tools toconstruct graphics models by hand, IBR uses real-world imagery torapidly create extremely photorealistic shape and appearancemodels. However, IBR results to date have mostly been restricted tostatic objects and s...
Creator:
Szeliski, Richard (Microsoft Research)
Created:
2006-02-07
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Various rich dynamics of vesicles under linear and nonlinearflows will be discussed. We present analytical and numericalresults on tank-treading motion, tumbling andvacillating-breathing (aka swinging, trembling). We thendiscuss the notion of transverse migration due to a wall and toa nonlinear flow. We show theoretical and exeprimental resultso...
Creator:
Misbah, Chaouqi (Université de Grenoble I (Joseph Fourier))
Created:
2009-12-10
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
Given a pair of graphs G1 and G2 and a vertex set of interest in G1, the vertex nomination (VN) problem seeks to find the corresponding vertices of interest in G2 (if they exist) and produce a rank list of the vertices in G2, with the corresponding vertices of interest in G2 concentrating, ideally, at the top of the rank list. In the setting of ...
Creator:
Lyzinski, Vince (University of Maryland)
Created:
2020-09-17
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
With the advent of high-resolution forecasts came new challenges for analyzing their performance. It is no longer satisfactory to report only the root mean square error or similar grid-point-by-grid-point accumulative summaries. Often such scores give misleading information caused by either double penalties (when a small error in timing or spati...
Creator:
Gilleland, Eric (National Center for Atmospheric Research)
Created:
2018-04-25
Contributed By:
University of Minnesota, Institute for Mathematics and its Applications.
