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  • Michael Collins
    Please consider submitting a paper Current teaching Spring 2015 COMS W4705 Natural Language Processing Online teaching In Spring 2013 I taught an online course on Natural Language Processing on Coursera Notes for the Coursera class are posted here Publications on Google scholar Bio My research interests are in natural language processing and machine learning I completed a PhD in computer science from the University of Pennsylvania in December 1998 From January 1999 to November 2002 I was a researcher at AT T Labs Research and from January 2003 until December 2010 I was an assistant associate professor at MIT I joined Columbia University in January 2011 Students and Postdocs Awards NSF career award Alfred P Sloan research fellowship ACL fellow faculty finalist for the 2012 Blavatnik award Best paper awards at EMNLP 2002 EMNLP 2004 UAI 2004 UAI 2005 CoNLL 2008 EMNLP 2010 Recently I ve been trying to make an effort to write up fairly comprehensive notes for topics I teach in statistical NLP So far I ve covered Language models Hidden Markov models and tagging sequence labeling problems PCFGs Lexicalized PCFGs IBM Models 1 and 2 for machine translation Phrase based translation models Log linear models MEMMs Log

    Original URL path: http://www.cs.columbia.edu/~mcollins/ (2016-02-17)
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  • Prof. Stephen A. Edwards
    II on a FPGA Some press My Office Actual Wisdom Facebook Advice CUPLA Reviews Advice for 3 2 Combined Plan CS Students I often teach on CVN which can sometimes be confusing for new faculty Stephen A Edwards is a tenured associate professor in the Computer Science Department of Columbia University He obtained his Ph D from the University of California Berkeley in 1997 his MS from Berkeley in 1994 and his BS from the California Institute of Technology in 1992 all in Electrical Engineering Before pursuing his academic career in 2001 he worked for two Electronic Design Automation EDA companies Simplex Solutions now part of Cadence and Synopsys Professor Edwards and his group explore automating the creation of software for embedded systems application specific computers hiding in a growing number of industrial and consumer systems They have developed numerous compilation techniques for the Esterel synchronous language for real time control and are also developing domain specific languages for device drivers and communication protocols My group does not offer internships summer or otherwise Consulting Litigation Support Expert Witness Services I have been engaged as an expert witness in various patent litigation cases involving software and computer architecture including an ITC

    Original URL path: http://www.cs.columbia.edu/~sedwards/ (2016-02-17)
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  • Steven K. Feiner
    his students has won the ACM UIST 2010 Lasting Impact Award and best paper awards at ACM UIST ACM CHI ACM VRST and IEEE ISMAR His lab created the first outdoor mobile augmented reality system using a see through display in 1996 and pioneered experimental applications of augmented reality to fields such as tourism journalism maintenance and construction In recent years Prof Feiner has been program co chair for IEEE

    Original URL path: http://www.cs.columbia.edu/~feiner/ (2016-02-17)
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  • Luis Gravano
    TODS 04 paper over multimedia databases TKDE 04 paper Snowball and QXtract building blocks for efficient information extraction ICDE 03 paper errata WebDB 03 paper DL 00 paper SDARTS a protocol and toolkit for metasearching JCDL 02 paper JCDL 01 paper GeoSearch a geographically aware search engine CIKM 03 paper VLDB 00 paper Ph D Students Eugene Agichtein graduated 5 2005 first employment Postdoc Researcher Microsoft Research current employment Associate Professor Department of Mathematics and Computer Science Emory University Pablo Barrio graduated 10 2015 Hila Becker graduated 10 2011 current employment Software Engineer Google Nicolás Bruno graduated 5 2003 first employment Researcher Microsoft Research current employment Software Engineer Google Wisam Dakka graduated 11 2008 current employment Software Engineer Google Thomas Effland Panagiotis Ipeirotis graduated 9 2004 current employment Associate Professor Stern School of Business New York University Alpa Jain graduated 9 2008 first employment Scientist Yahoo Labs current employment Software Engineer Google Amélie Marian graduated 9 2005 current employment Associate Professor Department of Computer Science Rutgers University Ioannis Paparrizos Fotis Psallidas Gonçalo Simões co advised by Helena Galhardas Some Recent Professional Activities ACM Transactions on Database Systems associate editor 2004 2010 ACM Transactions on Information Systems associate editor 1997 2005 IEEE Data Engineering Bulletin associate editor 2000 2002 Editor Special Issue on Text and Databases December 2001 Editor Special Issue on Next Generation Web Search September 2000 SIGMOD 2012 program chair WWW 2015 Web Search Systems and Applications track program committee member VLDB 2015 Industrial Track program committee member WWW 2016 Search Systems and Applications track program committee member Teaching and Advising Office Hours for Spring 2016 Mondays 9 30 11 30 a m both for cs4111 Introduction to Databases and for Columbia College juniors majoring in Computer Science No office hours on Monday February 8 2016 Instead I will

    Original URL path: http://www.cs.columbia.edu/~gravano/ (2016-02-17)
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  • Eitan Grinspun's home page
    axis The theory and accompanying implementation do not distinguish between forms of different dimension solids shells rods nor between manifold regions and non manifold junctions Consequently a single code accurately models a diverse range of elastoplastic behaviors including buckling writhing cutting and merging Emphasis on convergence to the continuum sets us apart from early unification efforts PDF bib Video Synthesizing Structured Image Hybrids Eric Risser Charles Han Rozenn Dahyot Eitan Grinspun SIGGRAPH ACM Transactions on Graphics 2010 Abstract Example based texture synthesis algorithms generate novel texture images from example data A popular hierarchical pixel based approach uses spatial jitter to introduce diversity at the risk of breaking coarse structure beyond repair We propose a multiscale descriptor that enables appearance space jitter which retains structure This idea enables repurposing of existing texture synthesis implementations for a qualitatively different problem statement and class of inputs generating hybrids of structured images PDF bib Project Higher order extended finite elements with harmonic enrichment functions for complex crack problems S E Mousavi E Grinspun N Sukumar International Journal for Numerical Methods in Engineering pp 560 574 2010 Abstract We analyze complex crack problems in elastic media using harmonic enrichment functions in a higher order extended finite element implementation The numerically computed enrichment function of a crack is the solution of the Laplace equation with discontinuous Dirichlet boundary condition along the crack and its interaction with branches or other cracks is realized by imposing vanishing Neumann boundary conditions along those cracks The classical finite element displacement approximation is enriched by adding the enrichment function of a crack through the framework of partition of unity A nested subgrid mesh is used in the Laplace solve with a rasterized approximation of a crack which simplifies the numerical integration no partitioning of finite elements is required Harmonic enrichment functions readily permit the extension to handle multiple interacting and branched cracks without any special treatment around the junction points Several numerical examples are presented that affirm the accuracy and effectiveness of the method when applied to complex crack configurations under mixed mode loading conditions PDF bib Harmonic enrichment functions A unified treatment of multiple intersecting and branched cracks in the extended finite element method S E Mousavi E Grinspun N Sukumar International Journal for Numerical Methods in Engineering pp 1306 1322 2010 Abstract A unifying procedure to numerically compute enrichment functions for elastic fracture problems with the extended finite element method is presented Within each element that is intersected by a crack the enrichment function for the crack is obtained via the solution of the Laplace equation with Dirichlet and vanishing Neumann boundary conditions A single algorithm emanates for the enrichment field for multiple cracks as well as intersecting and branched cracks without recourse to special cases which provides flexibility over existing approaches in which each case is treated separately Numerical integration is rendered to be simple there is no need for partitioning of the finite elements into conforming subdivisions for the integration of discontinuous or weakly singular kernels Stress intensity factor computations for different crack configurations are presented to demonstrate the accuracy and versatility of the proposed technique PDF bib Asynchronous Contact Mechanics David Harmon Etienne Vouga Breannan Smith Rasmus Tamstorf Eitan Grinspun SIGGRAPH ACM Transactions on Graphics 2009 Abstract We develop a method for reliable simulation of elastica in complex contact scenarios Our focus is on firmly establishing three parameter independent guarantees that simulations of well posed problems a have no interpenetrations b obey causality momentum and energy conservation laws and c complete in finite time We achieve these guarantees through a novel synthesis of asynchronous variational integrators kinetic data structures and a discretization of the contact barrier potential by an infinite sum of nested quadratic potentials In a series of two and three dimensional examples we illustrate that this method more easily handles challenging problems involving complex contact geometries sharp features and sliding during extremely tight contact PDF bib Project Video Enrichment Textures for Detailed Cutting of Shells Peter Kaufmann Sebastian Martin Mario Botsch Eitan Grinspun Markus Gross SIGGRAPH ACM Transactions on Graphics 2009 Abstract We present a method for simulating highly detailed cutting and fracturing of thin shells using low resolution simulation meshes Instead of refining or remeshing the underlying simulation domain to resolve complex cut paths we adapt the extended finite element method XFEM and enrich our approximation by custom designed basis functions while keeping the simulation mesh unchanged The enrichment functions are stored in enrichment textures which allows for fracture and cutting discontinuities at a resolution much finer than the underlying mesh similar to image textures for increased visual resolution Furthermore we propose harmonic enrichment functions to handle multiple intersecting arbitrarily shaped progressive cuts per element in a simple and unified framework Our underlying shell simulation is based on discontinuous Galerkin DG FEM which relaxes the restrictive requirement of C 1 continuous basis functions and thus allows for simpler C 0 continuous XFEM enrichment functions PDF bib Video Semantic Deformation Transfer Ilya Baran Daniel Vlasic Eitan Grinspun Jovan Popovic SIGGRAPH ACM Transactions on Graphics 2009 Abstract Transferring existing mesh deformation from one character to another is a simple way to accelerate the laborious process of mesh animation In many cases it is useful to preserve the semantic characteristics of the motion instead of its literal deformation For example when applying the walking motion of a human to a flamingo the knees should bend in the opposite direction Semantic deformation transfer accomplishes this task with a shape space that enables interpolation and projection with standard linear algebra Given several example mesh pairs semantic deformation transfer infers a correspondence between the shape spaces of the two characters This enables automatic transfer of new poses and animations PDF bib Video Implicit Explicit Variational Integration of Highly Oscillatory Problems Ari Stern Eitan Grinspun SIAM Multiscale Modeling and Simulation pp 1779 1794 2009 Abstract We derive a variational integrator for certain highly oscillatory problems in mechanics To do this we take a new approach to the splitting of fast and slow potential forces rather than splitting these forces at the level of the differential equations or the Hamiltonian we split the two potentials with respect to the Lagrangian action integral By using a different quadrature rule to approximate the contribution of each potential to the action we arrive at a geometric integrator that is implicit in the fast force and explicit in the slow force This can allow for significantly longer time steps to be taken compared to standard explicit methods such as Störmer Verlet at the cost of only a linear solve rather than a full nonlinear solve We also analyze the stability of this method in particular proving that it eliminates the linear resonance instabilities that can arise with explicit multiple time stepping methods Next we perform some numerical experiments studying the behavior of this integrator for two test problems a system of coupled linear oscillators for which we compare against the resonance behavior of the r RESPA method and slow energy exchange in the Fermi Pasta Ulam problem which couples fast linear oscillators with slow nonlinear oscillators Finally we prove that this integrator accurately preserves the slow energy exchange between the fast oscillatory components which explains the numerical behavior observed for the Fermi Pasta Ulam problem PDF bib Discrete Elastic Rods Miklós Bergou Max Wardetzky Stephen Robinson Basile Audoly Eitan Grinspun SIGGRAPH ACM Transactions on Graphics pp 1 12 2008 Abstract We present a discrete treatment of adapted framed curves parallel transport and holonomy thus establishing the language for a discrete geometric model of thin flexible rods with arbitrary cross section and undeformed configuration Our approach differs from existing simulation techniques in the graphics and mechanics literature both in the kinematic description we represent the material frame by its angular deviation from the natural Bishop frame as well as in the dynamical treatment we treat the centerline as dynamic and the material frame as quasistatic Additionally we describe a manifold projection method for coupling rods to rigid bodies and simultaneously enforcing rod inextensibility The use of quasistatics and constraints provides an efficient treatment for stiff twisting and stretching modes at the same time we retain the dynamic bending of the centerline and accurately reproduce the coupling between bending and twisting modes We validate the discrete rod model via quantitative buckling stability and coupled mode experiments and via qualitative knot tying comparisons PDF bib Project Video Multiscale Texture Synthesis Charles Han Eric Risser Ravi Ramamoorthi Eitan Grinspun SIGGRAPH ACM Transactions on Graphics pp 51 2008 Abstract Example based texture synthesis algorithms have gained widespread popularity for their ability to take a single input image and create a perceptually similar non periodic texture However previous methods rely on single input exemplars that can capture only a limited band of spatial scales For example synthesizing a continent like appearance at a variety of zoom levels would require an impractically high input resolution In this paper we develop a multiscale texture synthesis algorithm We propose a novel example based representation which we call an exemplar graph that simply requires a few low resolution input exemplars at different scales Moreover by allowing loops in the graph we can create infinite zooms and infinitely detailed textures that are impossible with current example based methods We also introduce a technique that ameliorates inconsistencies in the user s input and show that the application of this method yields improved interscale coherence and higher visual quality We demonstrate optimizations for both CPU and GPU implementations of our method and use them to produce animations with zooming and panning at multiple scales as well as static gigapixel sized images with features spanning many spatial scales PDF bib Project Video Robust Treatment of Simultaneous Collisions David Harmon Etienne Vouga Rasmus Tamstorf and Eitan Grinspun SIGGRAPH ACM Transactions on Graphics pp 1 4 2008 Abstract Robust treatment of complex collisions is a challenging problem in cloth simulation Some state of the art methods resolve collisions iteratively invoking a fail safe when a bound on iteration count is exceeded The best known fail safe rigidifies the contact region causing simulation artifacts We present a fail safe that cancels impact but not sliding motion considerably reducing artificial dissipation We equip the proposed fail safe with an approximation of Coulomb friction allowing finer control of sliding dissipation PDF bib Project Video Discrete Laplace operators No free lunch Max Wardetzky Saurabh Mathur Felix Kälberer and Eitan Grinspun Symposium on Geometry Processing pp 33 37 2007 Abstract Discrete Laplace operators are ubiquitous in applications spanning geometric modeling to simulation For robustness and efficiency many applications require discrete operators that retain key structural properties inherent to the continuous setting Building on the smooth setting we present a set of natural properties for discrete Laplace operators for triangular surface meshes We prove an important theoretical limitation discrete Laplacians cannot satisfy all natural properties retroactively this explains the diversity of existing discrete Laplace operators Finally we present a family of operators that includes and extends well known and widely used operators PDF bib Compressive Structured Light for Recovering Inhomogeneous Participating Media Jinwei Gu Shree Nayar Eitan Grinspun Peter Belhumeur Ravi Ramamoorthi Europian Conference on Computer Vision ECCV 2008 Abstract We propose a new method named compressive structured light for recovering inhomogeneous participating media Whereas conventional structured light methods emit coded light patterns onto the surface of an opaque object to establish correspondence for triangulation compressive structured light projects patterns into a volume of participating medium to produce images which are integral measurements of the volume density along the line of sight For a typical participating medium encountered in the real world the integral nature of the acquired images enables the use of compressive sensing techniques that can recover the entire volume density from only a few measurements This makes the acquisition process more efficient and enables reconstruction of dynamic volumetric phenomena Moreover our method requires the projection of multiplexed coded illumination which has the added advantage of increasing the signal to noise ratio of the acquisition Finally we propose an iterative algorithm to correct for the attenuation of the participating medium during the reconstruction process We show the effectiveness of our method with simulations as well as experiments on the volumetric recovery of multiple translucent layers 3D point clouds etched in glass and the dynamic process of milk drops dissolving in water PDF bib Project TRACKS Toward Directable Thin Shells Miklós Bergou Saurabh Mathur Max Wardetzky and Eitan Grinspun SIGGRAPH ACM Transactions on Graphics pp 50 2007 Abstract We combine the often opposing forces of artistic freedom and mathematical determinism to enrich a given animation or simulation of a surface with physically based detail We present a process called tracking which takes as input a rough animation or simulation and enhances it with physically simulated detail Building on the foundation of constrained Lagrangian mechanics we propose weak form constraints for tracking the input motion This method allows the artist to choose where to add details such as characteristic wrinkles and folds of various thin shell materials and dynamical effects of physical forces We demonstrate multiple applications ranging from enhancing an artist s animated character to guiding a simulated inanimate object PDF bib Project Video Efficient Simulation of Inextensible Cloth Rony Goldenthal David Harmon Raanan Fattal Michel Bercovier Eitan Grinspun SIGGRAPH ACM Transactions on Graphics 2007 Abstract Many textiles do not noticeably stretch under their own weight Unfortunately for better performance many cloth solvers disregard this fact We propose a method to obtain very low strain along the warp and weft direction using Constrained Lagrangian Mechanics and a novel fast projection method The resulting algorithm acts as a velocity filter that easily integrates into existing simulation code PDF bib Project Video Frequency Domain Normal Map Filtering Charles Han Bo Sun Ravi Ramamoorthi and Eitan Grinspun SIGGRAPH ACM Transactions on Graphics pp 28 2007 Abstract Filtering is critical for representing image based detail such as textures or normal maps across a variety of scales While mipmapping textures is commonplace accurate normal map filtering remains a challenging problem because of nonlinearities in shading ªwe cannot simply average nearby surface normals In this paper we show analytically that normal map filtering can be formalized as a spherical convolution of the normal distribution function NDF and the BRDF for a large class of common BRDFs such as Lambertian microfacet and factored measurements This theoretical result explains many previous filtering techniques as special cases and leads to a generalization to a broader class of measured and analytic BRDFs Our practical algorithms leverage a significant body of previous work that has studied lighting BRDF convolution We show how spherical harmonics can be used to filter the NDF for Lambertian and low frequency specular BRDFs while spherical von Mises Fisher distributions can be used for high frequency materials PDF bib Project Video Cubic Shells Akash Garg Eitan Grinspun Max Wardetzky Denis Zorin Symposium on Computer Animation pp 91 98 2007 Abstract Hinge based bending models are widely used in the physically based animation of cloth thin plates and shells We propose a hinge based model that is simpler to implement more efficient to compute and offers a greater number of effective material parameters than existing models Our formulation builds on two mathematical observations a the bending energy of curved flexible surfaces can be expressed as a cubic polynomial if the surface does not stretch b a general class of anisotropic materials those that are orthotropic is captured by appropriate choice of a single stiffness per hinge Our contribution impacts a general range of surface animation applications from isotropic cloth and thin plates to orthotropic fracturing thin shells PDF bib Video Discrete Quadratic Curvature Energies CAGD Most Cited Paper Award for 2010 Max Wardetzky Miklós Bergou David Harmon Denis Zorin and Eitan Grinspun Computer Aided Geometric Design pp 499 518 2007 Abstract This is preprint not a final copy We present a family of discrete isometric bending models IBMs for triangulated surfaces in 3 space These models are derived from an axiomatic treatment of discrete Laplace operators using these operators to obtain linear models for discrete mean curvature from which bending energies are assembled Under the assumption of isometric surface deformations we show that these energies are quadratic in surface positions The corresponding linear energy gradients and constant energy Hessians constitute an efficient model for computing bending forces and their derivatives enabling fast time integration of cloth dynamics with a two to three fold net speedup over existing nonlinear methods and near interactive rates for Willmore smoothing of large meshes PDF bib Project Video Computing discrete shape operators on general meshes Eurographics 2006 Best Paper 3rd Place Eitan Grinspun Yotam Gingold Jason Reisman Denis Zorin Eurographics Computer Graphics Forum pp 547 556 2006 Abstract Discrete curvature and shape operators which capture complete information about directional curvatures at a point are essential in a variety of applications simulation of deformable two dimensional objects variational modeling and geometric data processing In many of these applications objects are represented by meshes Currently a spectrum of approaches for formulating curvature operators for meshes exists ranging from highly accurate but computationally expensive methods used in engineering applications to efficient but less accurate techniques popular in simulation for computer graphics We propose a simple and efficient formulation for the shape operator for variational problems on general meshes using degrees of freedom associated with normals On the one hand it is similar in its simplicity to some of the discrete curvature operators commonly used in graphics on the other hand it passes a number of important convergence tests and produces consistent results for different types of meshes and mesh refinement PDF bib Addendum The associated addendum below describes a shape operator discretization based on triangle centered quadratic interpolation A note on the triangle centered quadratic interpolation discretization of the shape operator Jason Reisman Eitan Grinspun Denis Zorin Technical Report Department of Computer Science Columbia University and New York University 2007 Abstract In this note we consider a simple shape operator discretization for

    Original URL path: http://www.cs.columbia.edu/~eitan/ (2016-02-17)
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  • Julia Hirschberg
    Slides from a tutorial with a bibliography are also available for download Also I have written several general surveys of work on intonational meaning and text to speech synthesis including Communication and Prosody in Speech Communication 36 2002 an article in the Handbook of Pragmatics Pragmatics and Intonation 2003 and a section of the second edition of the Encyclopedia of Language and Linguistics on Speech Synthesis Prosody final draft See

    Original URL path: http://www.cs.columbia.edu/~julia/research_summary.htm (2016-02-17)
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  • Julia Hirschberg
    07 23 1999 with J Choi S Whittaker C Nakatani System And Method For Gisting Browsing and Searching Voicemail Using Automatic Speech Recognition filed 12 08 1999 with S Whittaker Method And Apparatus For Voice Mail Notes filed 12 16 1999 With S Greenspan and S Whittaker System And Method For Indexing Voice Mail Messages by Speaker filed 04 17 2000 with A Rosenberg S Parthasarathy and S Whittaker System

    Original URL path: http://www.cs.columbia.edu/~julia/publications_patents.htm (2016-02-17)
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  • Julia Hirschberg
    Recent Courses EECS 6898 From Data to Solutions Fall 2012 CS 4706 Spoken Language Processing Spring 2012 CS 4995 6998 Computational Approaches to Emotional Speech Fall 2011 CS 4705 Natural Language Processing Fall 2010 Office Hours Fall 2012 TBD Julia Hirschberg Professor Computer Science Columbia University Department of Computer Science 1214 Amsterdam Avenue M C 0401 450 CS Building New York NY 10027 email julia cs columbia edu phone 212

    Original URL path: http://www.cs.columbia.edu/~julia/teaching.htm (2016-02-17)
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