Godfried Toussaint
Godfried Theodore Patrick Toussaint (1944 – July 2019) was a Canadian computer scientist, a professor of computer science, and the head of the Computer Science Program at
He was a co-founder of the Annual ACM Symposium on Computational Geometry, and the annual Canadian Conference on Computational Geometry.
Along with Selim Akl, he was an author and namesake of the efficient "Akl–Toussaint algorithm" for the construction of the convex hull of a planar point set. This algorithm exhibits a computational complexity with expected value linear in the size of the input.[3] In 1980 he introduced the relative neighborhood graph (RNG) to the fields of pattern recognition and machine learning, and showed that it contained the minimum spanning tree, and was a subgraph of the Delaunay triangulation. Three other well known proximity graphs are the nearest neighbor graph, the Urquhart graph, and the Gabriel graph. The first is contained in the minimum spanning tree, and the Urquhart graph contains the RNG, and is contained in the Delaunay triangulation. Since all these graphs are nested together they are referred to as the Toussaint hierarchy.[4]
Biography
Toussaint was born in 1944[5] in Belgium.[6] After graduating in 1968 from the University of Tulsa,[7] he went to the University of British Columbia for graduate study, completing his Ph.D. there in 1972. His dissertation, Feature Evaluation Criteria and Contextual Decoding Algorithms in Statistical Pattern Recognition, was supervised by Robert W. Donaldson.[8]
He joined the
He died in July 2019[9] in Tokyo, Japan.[10] He was in Tokyo to present his work on "The Levenshtein distance as a measure of mirror symmetry and homogeneity for binary digital patterns" in a special session titled "Design & Computation in Geovisualization" convened by the International Cartographic Association Commission on Visual Analytics at the 2019 International Cartographic Conference.[11]
Mathematical research in music
He spent a year in the Music Department at
Awards
In 2018 he was awarded a Lifetime Achievement Award by the Canadian Association of Computer Science. In 1978 he was the recipient of the
Books and book chapters
- G. T. Toussaint, The Geometry of Musical Rhythm, Chapman and Hall/CRC, January 2013.
- G. T. Toussaint, Computational Geometry, Editor, North-Holland Publishing Company, Amsterdam, 1985.
- G. T. Toussaint, Computational Morphology, Editor, North-Holland Publishing Company, Amsterdam, 1988.
- E. D. Demaine, B. Gassend, J. O'Rourke, and G. T. Toussaint, "All polygons flip finitely... right?" Surveys on Discrete and Computational Geometry: Twenty Years Later, J. E. Goodman, J. Pach, and R. Pollack, Editors, in Contemporary Mathematics, Vol. 453, 2008, pp. 231–255.
- J. O'Rourke and G. T. Toussaint, "Pattern recognition", Chapter 51 in the Handbook of Discrete and Computational Geometry, Eds. J. E. Goodman and J. O'Rourke, Chapman & Hall/CRC, New York, 2004, pp. 1135–1162.
- M. Soss and G. T. Toussaint, "Convexifying polygons in 3D: a survey", in Physical Knots: Knotting, Linking, and Folding Geometric Objects in R3, AMS Special Session on Physical Knotting, Linking, and Unknotting, Eds. J. A. Calvo, K. Millett, and E. Rawdon, American Mathematical Society, Contemporary Mathematics, Vol. 304, 2002, pp. 269–285.
- G. T. Toussaint, "Applications of the Erdős–Nagy theorem to robotics, polymer physics and molecular biology", Año Mundial de la Matematica, Sección de Publicaciones de la Escuela Tecnica Superior de Ingenieros Industriales, Universidad Politecnica de Madrid, 2002, pp. 195–198.
- J. O'Rourke and G. T. Toussaint, "Pattern recognition", Chapter 43 in the Handbook of Discrete and Computational Geometry, Eds. J. E. Goodman and J. O'Rourke, CRC Press, New York, 1997, pp. 797–813.
- G. T. Toussaint, "Computational geometry and computer vision", in Vision Geometry, Contemporary Mathematics, Volume 119, R. A. Melter, A. Rozenfeld and P. Bhattacharya (editors), American Mathematical Society, 1991, pp. 213–224.
- G. T. Toussaint, "A graph-theoretical primal sketch", in Computational Morphology, G. T. Toussaint (ed.), North-Holland, 1988, pp. 229–260.
- G. T. Toussaint, "Movable separability of sets", in Computational Geometry, G. T. Toussaint (ed.), North-Holland Publishing Co., 1985, pp. 335–375.
References
- ^ New York University Abu Dhabi
- ^ G. Toussaint profile Archived 2011-05-23 at the Wayback Machine at McGill University
- ^ Selim G. Akl and Godfried T. Toussaint, "A fast convex hull algorithm," Information Processing Letters, Vol. 7, August 1978, pp. 219-222.
- ^ A. Adamatzky, "Developing proximity graphs by physarum polycephalum : Does the plasmodium follow the Toussaint hierarchy," Parallel Processing Letters, Vol. 19, No. 1, 2009, pp. 105-127.
- ^ Birth date from Library of Congress catalog entry, retrieved 2019-03-27
- ^ "Godfried Toussaint", Featured Authors, CRC Press, retrieved 2019-03-27
- ^ a b Biography, McGill university, retrieved 2019-03-27
- ^ Godfried Toussaint at the Mathematics Genealogy Project
- ^ Bose, Jit (July 19, 2019), "Godfried Toussaint", compgeom-announce mailing list
- ^ Mourning the Passing of Godfried Toussaint, July 22, 2019, retrieved 2019-07-30
- ^ Commission on Visual Analytics Activities at the 2019 ICC in Tokyo, June 13, 2019, retrieved 2019-07-30
- ^ G. T. Toussaint, "The Euclidean algorithm generates traditional musical rhythms", Proceedings of BRIDGES: Mathematical Connections in Art, Music, and Science, Banff, Alberta, Canada, July 31 to August 3, 2005, pp. 47–56.
- ^ "Flamenco Forensics", McGill Reporter, January 26, 2006.
- ^ G. Toussaint home page
- ^ The Harvard Gazette