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You and AI Conversations About AI Technologies and Their Implications for Society
You and AI Conversations about AI technologies and their implications for society SUPPORTED BY CONVERSATIONS ABOUT AI TECHNOLOGIES AND THEIR IMPLICATIONS FOR SOCIETY DeepMind1 2 CONVERSATIONS ABOUT AI TECHNOLOGIES AND THEIR IMPLICATIONS FOR SOCIETY You and AI Conversations about AI technologies and their implications for society Artificial Intelligence (AI) is the science of making computer systems smart, and an umbrella term for a range of technologies that carry out functions that typically require intelligence in humans. AI technologies already support many everyday products and services, and the power and reach of these technologies are advancing at pace. The Royal Society is working to support an environment of careful stewardship of AI technologies, so that their benefits can be brought into being safely and rapidly, and shared across society. In support of this aim, the Society’s You and AI series brought together leading AI researchers to contribute to a public conversation about advances in AI and their implications for society. CONVERSATIONS ABOUT AI TECHNOLOGIES AND THEIR IMPLICATIONS FOR SOCIETY 3 What AI can, and cannot, do The last decade has seen exciting developments in AI – and AI researchers are tackling some fundamental challenges to develop it further AI research seeks to understand what happens or inputs do not follow a standard intelligence is, and then recreate this through pattern, these systems cannot adapt their computer systems that can automatically rules or adjust their approach. perform tasks that require some level of reasoning or intelligence in humans. In the last decade, new methods that use learning algorithms have helped create In the past, AI research has concentrated computer systems that are more flexible on creating detailed rules for how to carry and adaptive, and Demis Hassabis FRS out a task and then developing computer (co-founder, DeepMind) has been at the systems that could carry out these rules; forefront of many of these developments. -
Numerical Computation with Rational Functions
NUMERICAL COMPUTATION WITH RATIONAL FUNCTIONS (scalars only) Nick Trefethen, University of Oxford and ENS Lyon + thanks to Silviu Filip, Abi Gopal, Stefan Güttel, Yuji Nakatsukasa, and Olivier Sète 1/26 1. Polynomial vs. rational approximations 2. Four representations of rational functions 2a. Quotient of polynomials 2b. Partial fractions 2c. Quotient of partial fractions (= barycentric) 2d. Transfer function/matrix pencil 3. The AAA algorithm with Nakatsukasa and Sète, to appear in SISC 4. Application: conformal maps with Gopal, submitted to Numer. Math. 5. Application: minimax approximation with Filip, Nakatsukasa, and Beckermann, to appear in SISC 6. Accuracy and noise 2/26 1. Polynomial vs. rational approximation Newman, 1964: approximation of |x| on [−1,1] −휋 푛 퐸푛0 ~ 0.2801. ./푛 , 퐸푛푛 ~ 8푒 Poles and zeros of r: exponentially clustered near x=0, exponentially diminishing residues. Rational approximation is nonlinear, so algorithms are nontrivial. poles There may be nonuniqueness and local minima. type (20,20) 3/26 2. Four representations of rational functions Alpert, Carpenter, Coelho, Gonnet, Greengard, Hagstrom, Koerner, Levy, Quotient of polynomials 푝(푧)/푞(푧) SK, IRF, AGH, ratdisk Pachón, Phillips, Ruttan, Sanathanen, Silantyev, Silveira, Varga, White,… 푎푘 Beylkin, Deschrijver, Dhaene, Drmač, Partial fractions 푧 − 푧 VF, exponential sums Greengard, Gustavsen, Hochman, 푘 Mohlenkamp, Monzón, Semlyen,… Berrut, Filip, Floater, Gopal, Quotient of partial fractions 푛(푧)/푑(푧) Floater-Hormann, AAA Hochman, Hormann, Ionita, Klein, Mittelmann, Nakatsukasa, Salzer, (= barycentric) Schneider, Sète, Trefethen, Werner,… 푇 −1 Antoulas, Beattie, Beckermann, Berljafa, Transfer function/matrix pencil 푐 푧퐵 − 퐴 푏 IRKA, Loewner, RKFIT Druskin, Elsworth, Gugercin, Güttel, Knizhnerman, Meerbergen, Ruhe,… Sometimes the boundaries are blurry! 4/26 2a. -
2011 Mathematics Newsletter
AUTUMN 2011 NEWSLETTER OF THE DEPARTMENT OF MATHEMATICS AT THE UNIVERSITY OF WASHINGTON Mathematics NEWS 1 DEPARTMENT OF MATHEMATICS NEWS MESSAGE FROM THE CHAIR It has been another exciting year The positive developments reported in this newsletter stand for our department. The work of in contrast to a backdrop of (global) financial and politi- the faculty has been recognized cal uncertainty. In the fourth year of the financial crisis, in a number of ways, includ- the end is not yet in sight. Repeated cuts in state support, ing the AMS Bôcher Prize and coupled with tuition increases, spell a fundamental shift the SIAM Kleinman Prize pre- in the funding of state universities. At the same time, the sented to Gunther Uhlmann, need to re-tool to pursue new career paths in a changing and the NSF CAREER award to economy, the return of soldiers from overseas deployments, Max Lieblich. As you will see on and the coming of age of the baby-boom echo generation page 15, the numbers of majors bring increasing numbers of students to our campus and to in the Mathematics program and the joint ACMS (Applied our department. and Computational Mathematical Sciences) program have Until the situation settles, new resources are generally made continued to rise, as have the numbers of degrees awarded. available to us in the form of temporary allocations instead In addition, these programs attract outstanding students of tenure-track faculty positions, which would require long- who continue to make us proud. For example, Math majors term financial commitments. This policy is understandable. -
An Extension of Matlab to Continuous Functions and Operators∗
SIAM J. SCI. COMPUT. c 2004 Society for Industrial and Applied Mathematics Vol. 25, No. 5, pp. 1743–1770 AN EXTENSION OF MATLAB TO CONTINUOUS FUNCTIONS AND OPERATORS∗ † † ZACHARY BATTLES AND LLOYD N. TREFETHEN Abstract. An object-oriented MATLAB system is described for performing numerical linear algebra on continuous functions and operators rather than the usual discrete vectors and matrices. About eighty MATLAB functions from plot and sum to svd and cond have been overloaded so that one can work with our “chebfun” objects using almost exactly the usual MATLAB syntax. All functions live on [−1, 1] and are represented by values at sufficiently many Chebyshev points for the polynomial interpolant to be accurate to close to machine precision. Each of our overloaded operations raises questions about the proper generalization of familiar notions to the continuous context and about appropriate methods of interpolation, differentiation, integration, zerofinding, or transforms. Applications in approximation theory and numerical analysis are explored, and possible extensions for more substantial problems of scientific computing are mentioned. Key words. MATLAB, Chebyshev points, interpolation, barycentric formula, spectral methods, FFT AMS subject classifications. 41-04, 65D05 DOI. 10.1137/S1064827503430126 1. Introduction. Numerical linear algebra and functional analysis are two faces of the same subject, the study of linear mappings from one vector space to another. But it could not be said that mathematicians have settled on a language and notation that blend the discrete and continuous worlds gracefully. Numerical analysts favor a concrete, basis-dependent matrix-vector notation that may be quite foreign to the functional analysts. Sometimes the difference may seem very minor between, say, ex- pressing an inner product as (u, v)orasuTv. -
Householder Triangularization of a Quasimatrix
IMA Journal of Numerical Analysis (2010) 30, 887–897 doi:10.1093/imanum/drp018 Advance Access publication on August 21, 2009 Householder triangularization of a quasimatrix LLOYD N.TREFETHEN† Oxford University Computing Laboratory, Wolfson Building, Parks Road, Downloaded from Oxford OX1 3QD, UK [Received on 4 July 2008] A standard algorithm for computing the QR factorization of a matrix A is Householder triangulariza- tion. Here this idea is generalized to the situation in which A is a quasimatrix, that is, a ‘matrix’ whose http://imajna.oxfordjournals.org/ ‘columns’ are functions defined on an intervala [ , b]. Applications are mentioned to quasimatrix least squares fitting, singular value decomposition and determination of ranks, norms and condition numbers, and numerical illustrations are presented using the chebfun system. Keywords: Householder triangularization; QR factorization; chebfun; quasimatrix; singular value decom- position. 1. QR factorization and Householder triangularization at Radcliffe Science Library, Bodleian Library on April 18, 2012 Let A be an m n matrix, where m n. A (reduced) QR factorization of A is a factorization × > x x x x q q q q r r r r x x x x q q q q r r r A QR, x x x x q q q q r r , (1.1) = x x x x q q q q r x x x x q q q q x x x x q q q q where Q is m n with orthonormal columns and R is upper triangular. Here and in subsequent equations we illustrate our× matrix operations by schematic pictures in which x denotes an arbitrary entry, r denotes an entry of an upper triangular matrix, q denotes an entry of an orthonormal column and a blank denotes a zero. -
Publications by Lloyd N. Trefethen
Publications by Lloyd N. Trefethen I. Books I.1. Numerical Conformal Mapping, editor, 269 pages. Elsevier, 1986. I.2. Finite Difference and Spectral Methods for Ordinary and Partial Differential Equations, x+315 pages. Graduate textbook, privately published at http://comlab.ox.ac.uk/nick.trefethen/, 1996. I.3. Numerical Linear Algebra, with David Bau III, xii+361 pages. SIAM, 1997. I.4. Spectral Methods in MATLAB, xviii+165 pages. SIAM, 2000. I.5. Schwarz-Christoffel Mapping, with Tobin A. Driscoll, xvi+132 pages. Cambridge U. Press, 2002. I.6. Spectra and Pseudospectra: The Behavior of Nonnormal Matrices and Operators, with Mark Embree, xviii+606 pages. Princeton U. Press, 2005. I.7. Trefethen’s Index Cards: Forty years of Notes about People, Words, and Mathematics, xv + 368 pages. World Scientific Publishing, 2011. I.8. Approximation Theory and Approximation Practice. SIAM, to appear in 2013. In addition to these a book has been published by other authors about the international problem solving challenge I organised in 2002 (item VIII.8 below): F. Bornemann, D. Laurie, S. Wagon and D. Waldvogel, The SIAM 100-Digit Challenge, SIAM, 2004, to appear in German translation as Abenteuer Numerik: Eine Führung entlang der Herausforderung von Trefethen, Springer, 2006. II. Finite difference and spectral methods for partial differential equations II.1. Group velocity in finite difference schemes. SIAM Review 24 (1982), 113-136. II.2. Group velocity interpretation of the stability theory of Gustafsson, Kreiss, and Sundström. J. Comp. Phys. 49 (1983), 199-217. II.3. On Lp-instability and dispersion at discontinuities in finite difference schemes. -
Career Pathway Tracker 35 Years of Supporting Early Career Research Fellows Contents
Career pathway tracker 35 years of supporting early career research fellows Contents President’s foreword 4 Introduction 6 Scientific achievements 8 Career achievements 14 Leadership 20 Commercialisation 24 Public engagement 28 Policy contribution 32 How have the fellowships supported our alumni? 36 Who have we supported? 40 Where are they now? 44 Research Fellowship to Fellow 48 Cover image: Graphene © Vertigo3d CAREER PATHWAY TRACKER 3 President’s foreword The Royal Society exists to encourage the development and use of Very strong themes emerge from the survey About this report science for the benefit of humanity. One of the main ways we do that about why alumni felt they benefited. The freedom they had to pursue the research they This report is based on the first is by investing in outstanding scientists, people who are pushing the wanted to do because of the independence Career Pathway Tracker of the alumni of University Research Fellowships boundaries of our understanding of ourselves and the world around the schemes afford is foremost in the minds of respondents. The stability of funding and and Dorothy Hodgkin Fellowships. This us and applying that understanding to improve lives. flexibility are also highly valued. study was commissioned by the Royal Society in 2017 and delivered by the Above Thirty-five years ago, the Royal Society The vast majority of alumni who responded The Royal Society has long believed in the Careers Research & Advisory Centre Venki Ramakrishnan, (CRAC), supported by the Institute for President of the introduced our University Research Fellowships to the survey – 95% of University Research importance of identifying and nurturing the Royal Society. -
Mathematics People
Mathematics People Ooguri Receives Chunichi Turaev and Virelizier Awarded Cultural Award Balaguer Prize Hirosi Ooguri of the California Vladimir Turaev of Indiana Uni- Institute of Technology has been versity and Alexis Virelizier of honored with the 2016 Chunichi Université Lille 1 have been awarded Cultural Award. The award carries the 2016 Ferran Sunyer i Balaguer a cash prize of 2 million yen (ap- Prize for their monograph Monoidal proximately US$20,000). Categories and Topological Field According to the prize citation, Theory. The monograph introduces Ooguri was honored for the “devel- monoidal categories and Penrose’s opment of innovative methods of graphical calculus; gives an alge- modern mathematics in high energy braic description of the center of Hirosi Ooguri theory.” His work involves “creating monoidal categories based on the Vladimir Turaev new theoretical tools in quantum theory of Hopf monads as devel- field theory and superstring theory.” He is especially oped by Virelizier and coauthors; known for his work on topological string theory, “which explains topological quantum field has had broad applications ranging from black hole phys- theories, including fundamental ics to algebraic geometry and knot theory in mathematics.” earlier work of Reshetihkin-Turaev Ooguri is a past recipient of the AMS Eisenbud Prize and Turaev-Viro; and shows how to (2008), a Humboldt Research Award (2008), the Nishina present ribbon graphs by diagrams Memorial Prize (2009), a Simons Investigator Award on skeletons of 3-manifolds and (2012), and the Kodansha Prize for Science Books of define graph topological quantum Japan (2014) for his popular science book, Introduction to field theories by means of state Superstring Theory. -
Reference and Book List
Reference and Book List The Reference section of the Notices Upcoming Deadlines and for AMS scholarships. See http:// is intended to provide the reader with October 10, 2003: Applications for www.mccme.ru/mathinmoscow or frequently sought information in AWM Collaborative Research Grants contact Math in Moscow, P.O. Box 524, an easily accessible manner. New for Women. See the AWM website, Wynnewood, PA 19096; fax: +7095- information is printed as it becomes http://www.awm-math.org/news/ 291-65-01; email: [email protected]. For available and is referenced after the collab.html. information about and application first printing. As soon as information October 15, 2003: Proposals for NSA forms for the AMS scholarships, see is updated or otherwise changed, it Grant and Sabbatical Programs. See http://www.ams.org/careers-edu/ will be noted in this section. http://www.nsa.gov/programs/ mimoscow.html or contact Math in msp/grants.html. Moscow Program, Membership and Contacting the Notices October 15, 2003: Applications for Programs Department, American The preferred method for contacting spring semester of Math in Moscow Mathematical Society, 201 Charles the Notices is electronic mail. The editor is the person to whom to send Where to Find It articles and letters for consideration. A brief index to information that appears in this and previous issues. Articles include feature articles, AMS Bylaws—November 2003 p. 1283 memorial articles, communications, AMS Email Addresses—November 2003, p. 1266 opinion pieces, and book reviews. The AMS Ethical Guidelines—June/July 2002, p. 706 editor is also the person to whom to AMS Officers 2002 and 2003 (Council, Executive Committee, send news of unusual interest about Publications Committees, Board of Trustees)—May 2003, p. -
Marcus Du Sautoy Cutting an Impressive Figure
MARCUS DU SAUTOY CUTTING AN IMPRESSIVE FIGURE Mathematician Marcus du Sautoy is Science, for The Times. His books include The Music using his passion for the subject to of the Primes and Finding Moonshine. inspire a new generation of genius. And his own inspiration? “One of my heroes is Sir Christopher Zeeman. He’s a first rate mathematician He is an EPSRC senior media fellow and was but also a great communicator. I went to see the appointed University of Oxford’s Simonyi Professor Christmas Lecture he gave when I was 13 years for the Public Understanding of Science in 2008 – old and I came away saying ‘I want to be him when succeeding Professor Richard Dawkins. I grow up’.” “Maths is a way of understanding the way the world Thirty years later, du Sautoy is at the top of his field. works,” says du Sautoy. “It’s about seeing where you His career accolades range from the Berwick Prize are coming from and, more excitingly, predicting of the London Mathematical Society to being listed what happens next. It is the language of nature and as one of Esquire Magazine’s 100 most influential it is a way of unlocking the secrets of the universe.” men under 40. He recently wrote and presented BBC4’s The Story “Without EPSRC’s support there is no way I could of Maths, and has presented a number of Horizon have made the same impact,” he says. “The senior programmes. He is a regular contributor to media fellows scheme is so inspired that I am newspapers, including a weekly column, Sexy pushing for more positions to be created.” “IT IS ESSENTIAL THAT SCIENCE HAS AMBASSADORS TO COMMUNICATE THE EXCITEMENT AND IMPORTANCE OF SCIENCE IN SOCIETY.”. -
Efficient Shadowing of High Dimensional Chaotic Systems With
Efficient Shadowing of High Dimensional Chaotic Systems with the Large Astrophysical N-body Problem as an Example by Wayne Hayes A thesis submitted in conformity with the requirements for the degree of Master of Science Graduate Department of Computer Science University of Toronto c Copyright by Wayne Hayes 1995 Efficient Shadowing of High Dimensional Chaotic Systems with the Large Astrophysical N-body Problem as an Example Wayne Hayes Master of Science Department of Computer Science University of Toronto January 1995 Abstract N-body systems are chaotic. This means that numerical errors in their solution are magnified exponentially with time, perhaps making the solutions useless. Shadowing tries to show that numerical solutions of chaotic systems still have some validity. A previously published shadowing refinement algorithm is optimized to give speedups of order 60 for small problems and asymptotic speedups of O(N) on large problems. This optimized algorithm is used to shadow N-body systems with up to 25 moving particles. Preliminary results suggest that average shadow length scales roughly as 1=N, i.e., shadow lengths decrease rapidly as the number of phase-space dimensions of the system is increased. Some measures of simulation error for N-body systems are discussed that are less stringent than shadowing. Many areas of further research are discussed both for high-dimensional shadowing, and for N-body measures of error. -5 Acknowledgements I thank my supervisor, Prof. Ken Jackson, for many insightful conversations during the devel- opment of the ideas in this thesis, and for helpful comments on the text. My second reader, Dr. -
Chebfun Guide 1St Edition for Chebfun Version 5 ! ! ! ! ! ! ! ! ! ! ! ! ! ! Edited By: Tobin A
! ! ! Chebfun Guide 1st Edition For Chebfun version 5 ! ! ! ! ! ! ! ! ! ! ! ! ! ! Edited by: Tobin A. Driscoll, Nicholas Hale, and Lloyd N. Trefethen ! ! ! Copyright 2014 by Tobin A. Driscoll, Nicholas Hale, and Lloyd N. Trefethen. All rights reserved. !For information, write to [email protected].! ! ! MATLAB is a registered trademark of The MathWorks, Inc. For MATLAB product information, please write to [email protected]. ! ! ! ! ! ! ! ! Dedicated to the Chebfun developers of the past, present, and future. ! Table of Contents! ! !Preface! !Part I: Functions of one variable! 1. Getting started with Chebfun Lloyd N. Trefethen! 2. Integration and differentiation Lloyd N. Trefethen! 3. Rootfinding and minima and maxima Lloyd N. Trefethen! 4. Chebfun and approximation theory Lloyd N. Trefethen! 5. Complex Chebfuns Lloyd N. Trefethen! 6. Quasimatrices and least squares Lloyd N. Trefethen! 7. Linear differential operators and equations Tobin A. Driscoll! 8. Chebfun preferences Lloyd N. Trefethen! 9. Infinite intervals, infinite function values, and singularities Lloyd N. Trefethen! 10. Nonlinear ODEs and chebgui Lloyd N. Trefethen Part II: Functions of two variables (Chebfun2) ! 11. Chebfun2: Getting started Alex Townsend! 12. Integration and differentiation Alex Townsend! 13. Rootfinding and optimisation Alex Townsend! 14. Vector calculus Alex Townsend! 15. 2D surfaces in 3D space Alex Townsend ! ! Preface! ! This guide is an introduction to the use of Chebfun, an open source software package that aims to provide “numerical computing with functions.” Chebfun extends MATLAB’s inherent facilities with vectors and matrices to functions and operators. For those already familiar with MATLAB, much of what Chebfun does will hopefully feel natural and intuitive. Conversely, for those new to !MATLAB, much of what you learn about Chebfun can be applied within native MATLAB too.