Dr Joab Winkler

PGT Admissions Tutor

Telephone: +44 (0) 114 222 1834

Member of the Machine Learning research group
Personal website: staffwww.dcs.shef.ac.uk/people/J.Winkler/


Selected publications | All publications

Dr Joab Winkler



Joab Winkler is a Reader in The Department of Computer Science at The University of Sheffield. He obtained his undergraduate and PhD degrees at Imperial College London and University College London, respectively. He worked for a few years in industry, before returning to university to conduct research into algebraic and numerical properties of curves and surfaces in computer-aided design systems. He has maintained this research interest, but he has recently applied the methods used in this work to the computation of multiple roots of a polynomial and the deblurring of an image.

Other professional activities and achievements

  • Awarded an EPSRC Advanced Research Fellowship (1995)
  • Co-organiser of a workshop, supported by the EPSRC, on The Representation and Management of Uncertainty in Geometric Computations (2001)
  • Co-organiser of The Sheffield Machine Learning Workshop, supported by the EPSRC (2004)
  • Organised the Summer School, supported by the EPSRC, Solving Polynomial Equations and Structured Matrix Methods for Approximate GCD Computations (2007)
  • Awarded a Global Research Award by The Royal Academy of Engineering (2010-2011)
  • Co-organiser of a conference in Kalamata, Greece on structured methods in numerical linear and multilinear algebra (2014)


Joab Winkler’s main research interest is the algebraic and numerical properties of curves and surfaces in computer-aided design systems. Most of this work has been performed using resultant matrices, and this has led him to consider more general issues of robust computations on polynomials that are corrupted by added noise. Examples include the computation of a structured low rank approximation of the Sylvester resultant matrix, the deconvolution of two polynomials and the determination of an approximate greatest common divisor of two polynomials. He has developed a polynomial root solver for the determination of multiple roots of the theoretically exact form of a polynomial, when the coefficients of the given polynomial are corrupted by added noise. More recently, he has applied the methods used in this work on polynomials to the deblurring of an image.



  • Travel Grant, EPSRC, 07/2001 to 08/2001, £1,430, as PI
  • Tensor Tomography for the Three Dimensional Photoelasticity, EPSRC, 11/2002 to 04/2006, £38,818, as PI
  • Robust Computations in Geometric Modelling, EPSRC, 02/2005 to 01/2008, £71,785, as PI
  • Travel Grant, EPSRC, 10/2005 to 01/2006, £4,100, as PI
  • Polynomials and geometric modelling, ROYAL ACADEMY OF ENGINEERING (THE), 01/2010 to 12/2012, £23,613, as PI