- 914th Meeting of the American
Mathematical Society, Lawrenceville, New Jersey, USA, October 5-6, 1996,
"
*On Removing Degeneracies in Computational Geometry*." - Carleton Algorithmic Theory
Symposium, Ottawa, Canada, September 28, 1996, "
*On Removing Degeneracies in Computational Geometry*." - Conference on Facility Location,
University of Sevilla, Spain, April 22-23, 1996, "
*Computational Geometry and Facility Location*."

- Computational Geometry Day,
University of Newcastle, Australia, November 29, 1995, "
*Drawing Nice Projections of Objects in Space*." - 4th International Workshop
on Algorithms and Data Structures, Kingston, Canada, August 16-18, 1995,
"
*Quadrangulations of Planar Sets."* - VI Encuentro de Geometria
Computacional, Barcelona, Spain, July 5-7, 1995,
*"Quadrangulations."*

- Third Annual Symposium on
Document Analysis and Information Retrieval, Alexis Park Hotel, Las Vegas,
Nevada, April 12, 1994
*"Computational Geometry for Document Analysis."* - 892nd Meeting of the American
Mathematical Society, Polytechnic University, Brooklyn, New York, April
10, 1994,
*"Some Aperture-Angle Optimization Problems."* - Twenty Third Computational
Geometry Day, Courant Institute of Mathematical Sciences, New York University,
March 11, 1994,
*"Geometric and Computational Aspects of Manufacturing Processes."*

- National Science Foundation
Regional Geometry Institute, Smith College, Northampton, Massachussetts,
July 12, 1993,
*"Triangulations and Arrangements."* - National Science Foundation
Regional Geometry Institute, Smith College, Northampton, Massachussetts,
July 12, 1993,
*"Computational Geometric Topics Suitable for High School."* - National Science Foundation
Regional Geometry Institute, Smith College, Northampton, Massachussetts,
July 13, 1993,
*"Separating Objects with Translations."* - National Science Foundation
Regional Geometry Institute, Smith College, Northampton, Massachussetts,
July 14, 1993,
*"Triangulating a Set of Line Segments."* - National Science Foundation
Regional Geometry Institute, Smith College, Northampton, Massachussetts,
July 14, 1993,
*"Computing Geometric Properties of Arrangements of Lines and Line Segments."* - IV Encuentro de Geometria
Computacional, Granada, Spain, June 1, 1993,
*"Aproximación Poligonal de Curvas en dos y tres Dimensiones."*

- Canadian Conference on Electrical
and Computer Engineering, Toronto, Canada, September 14, 1992,
*"The Use of Proximity Graphs in Image Analysis and Computer Vision."* - Séptimo Coloquio de
Teoría de las Gráficas, Combinatoria y sus Aplicaciones,
Universidad Autónoma de Zacatecas, México, February 27, 1992,
*"Aplicación de la Teoría de Gráficas a la Aproximación Poligonal de Curvas.*

- 2nd Japan International Symposium
of the Society for the Advancement of Materials and Process Engineering,
Chiba, Japan, December 14, 1991,
*"Computing Morphological Properties of Arrangements of Lines."* - The Fifth Annual Computer
Science Days `91, Memorial University of Newfoundland, St. John's, Newfoundland,
October 17-18, 1991,
*"Computing Shortest Transversals of Sets."* - IEEE Computer Society Conference
on Computer Vision & Pattern Recognition, Lahaina, Maui, Hawaii, June
3-6, 1991,
*"Computational Geometry and Computer Vision."* - Sexto Coloquio de Teoría
de las Gráficas, Combinatoria y sus Aplicaciones, Guanajuato, México,
March 4-8, 1991,
*"Calculo de Propiedades Geometricas de Arreglos de Líneas."*

- Workshop on the Foundation
of Computer Graphics, Asian Institute of Technology, Bangkok, Thailand,
December 6-20, 1990,
*"Computational Geometric Aspects of Visibility."* - The 3rd Tokyo Algorithms Day,
University of Tokyo, December 3, 1990,
*"Computing Geometric Properties of Line Arrangements."* - Fifteenth Computational Geometry
Day, Courant Institute of Mathematical Sciences, New York University, New
York, November 9, 1990,
*"Computing Extremal Transversals of Sets."* - 2nd Canadian Conference on
Computational Geometry, University of Ottawa, August 6, 1990,
*"Computing Geometric Properties of Arrangements."* - Computer Graphics International'90,
Singapore, June 26, 1990,
*"Computational Geometric Aspects of Illumination and Visibility."* - Third Cumberland Conference
on Graph Theory and Applications to Computer Science, University of Louisville,
Kentucky, May 17-19, 1990,
*"Graph theory, Computational Geometry, & Morphology."* - V Coloquio de Teoría
de las Gráficas, Combinatoria y sus Aplicaciones, Universidad Michoacana
de San Nicolas de Hidalgo, Casa de la Cultura, Morelia, México,
March 2nd, 1990,
*"Gráficas de Proximidad en Problemas de Visión Computacional."* - V Coloquio de Teoría
de las Gráficas, Combinatoria y sus Aplicaciones, Universidad Michoacana
de San Nicolas de Hidalgo, Casa de la Cultura, Morelia, México,
February 27, 1990,
*"Triangulacion de Poligonos."*

- First Workshop on Proximity
Graphs, New Mexico State University, December 2, 1989,
*"Some unsolved problems on proximity graphs."* - First Workshop on Proximity
Graphs, New Mexico State University, Las Cruces, December 2, 1989,
*"Proximity graphs in computer vision."* - Meeting of the American Mathematical
Society, Stevens Institute of Technology, Hoboken, New Jersey, October
22, 1989,
*"Computational geometry and computer vision."*

- 13th IFIP Conference on System
Modelling and Optimization, Tokyo, Japan, Sept.1st., 1987,
*"Relative Convex Hulls of Sets and their Applications."* - Workshop on Computational
Geometry and Discrete Algorithms, Osaka Electro-Communication University,
Osaka, Japan, Sept. 5, 1987,
*"Relative Convex Hulls of Sets and their Applications."*

- Computer Science and Statistics:
16th Symposium on the Interface, Atlanta, U.S.A., March 1984, G.T. Toussaint,
B.K. Bhattacharya, and R.S. Poulsen,
*"The Application of Voronoi Diagrams to Nonparametric Decision Rules."*

- IEEE International Symposium
on Information Theory, St. Jovite, Canada, September, 1983,
*"The Complexity of Movement."* - IEEE International Symposium
on Information Theory, St. Jovite, Canada, September, 1983, G.T. Toussaint,
and B.K. Bhattacharya,
*"On Geometric Algorithms That use the Furthest Point Voronoi Diagram."*

- 86th Summer Meeting of the
American Mathematical Society, August 21-26, 1982, Toronto,
*"Distance and visibility problems in computational geometry."*

- NATO ASI on Pattern Recognition
Theory and Practice, Oxford University, April 1981,
*"Computational Geometric Problems in Pattern Recognition."*

- Fifth International Conference
on Pattern Recognition, Miami, December 1980,
*"Pattern Recognition and Geometrical Complexity."*

- IEEE Conference on Pattern
Recognition and Image Processing, June 1977, Troy, N.Y.,
*"The Use of Context in Pattern Recognition."*

- Conference on Measures of
Information and their Application, August 1974, Bombay, India,
*"On Some Measures of Information and their Application to Pattern Recognition."* - Second International Joint
Conference on Pattern Recognition, August 1974, Copenhagen, Denmark,
*"Recent Progress in Statistical Methods Applied to Pattern Recognition."*

- Computer Science Colloquium,
University of Minnesota, Minneapolis, Minnesota, U.S.A., March 3, 1997,
*"On Removing Non-Degeneracy Assumptions in Computational Geometry."*

- Computational Geometry Seminar,
Dept. of Applied Mathematics II, Universidad Politecnica de Catalunya,
Barcelona, Spain, July 10, 1996, "
*Removing Degeneracies in Computational Geometry*." - Computational Geometry Seminar,
Dept. of Applied Mathematics II, Universidad Politecnica de Catalunya,
Barcelona, Spain, July 3, 1996, "
*Facility Location*." - Computational Geometry Seminar,
Dept. of Applied Mathematics II, Universidad Politecnica de Catalunya,
Barcelona, Spain, June 18, 1996, "
*Mobility of Objects in Space - II*." - Computational Geometry Seminar,
Dept. of Applied Mathematics II, Universidad Politecnica de Catalunya,
Barcelona, Spain, June 12, 1996, "
*Mobility of Objects in Space - I*." - Computational Geometry Seminar,
Dept. of Applied Mathematics II, Universidad Politecnica de Catalunya,
Barcelona, Spain, June 5, 1996, "
*Computing Shortest Transversals of Planar Sets*." - Computational Geometry Seminar,
Dept. of Applied Mathematics II, Universidad Politecnica de Catalunya,
Barcelona, Spain, May 29, 1996, "
*Triangulating a Simple Polygon Efficiently in Practice*." - Computational Geometry Seminar,
Dept. of Applied Mathematics II, Universidad Politecnica de Catalunya,
Barcelona, Spain, May 22, 1996, "
*Proximity Graphs and Applications*." - Computational Geometry Seminar,
Dept. of Applied Mathematics, Universidad Politecnica de Madrid, Spain,
May 8, 1996, "
*Removing Degeneracies in Computational Geometry*." - Computational Geometry Seminar,
Dept. of Applied Mathematics, Universidad Politecnica de Madrid, Spain,
April 30, 1996, "
*Facility Location*." - Conference on Computational
Geometry and Facility Location, Universidad de Sevilla Spain, April 22,
1996, "
*Facility Location and Computational Geometry*." - Computational Geometry Seminar,
Dept. of Applied Mathematics, Universidad Politecnica de Madrid, Spain,
April 17, 1996, "
*Mobility of Objects in Space - II*." - Computational Geometry Seminar,
Dept. of Applied Mathematics, Universidad Politecnica de Madrid, Spain,
April 12, 1996, "
*Mobility of Objects in Space - I*." - Computational Geometry Seminar,
Dept. of Applied Mathematics, Universidad Politecnica de Madrid, Spain,
April 10, 1996, "
*Aperture-Angle Optimization in Two and Three Dimensions*." - Computational Geometry Seminar,
Dept. of Applied Mathematics, Universidad Politecnica de Madrid, Spain,
March 26, 1996, "
*Computing Shortest Transversals of Planar Sets."* - Computational Geometry Seminar,
Dept. of Applied Mathematics, Universidad Politecnica de Madrid, Spain,
March 22, 1996, "
*Quadrangulations of Planar Sets."* - Computational Geometry Seminar,
Dept. of Applied Mathematics, Universidad Politecnica de Madrid, Spain,
March 20, 1996, "
*Proximity**Graphs and Their Applications."* - Computational Geometry Seminar,
Dept. of Applied Mathematics, Universidad Politecnica de Madrid, Spain,
March 13, 1996, "
*Efficient**Triangulation of Planar Sets."*

- Computer Science Seminar,
University of New South Wales, Australia, December 18, 1995, "
*Computing**Quadrangulations of Sets."* - Electrical and Computer Engineering
Seminar, University of Newcastle, Australia, November 20, 1995, "
*Movable Separability of Objects in Space*." - Basser Department of Computer
Science Seminar, University of Sydney, Australia, November 2, 1995, "
*Computing**Quadrangulations of Sets."* - Computer Science Seminar,
University of Newcastle, Australia, October 18, 1995, "
*Computing**Quadrangulations of Sets."* - Computing Science Seminar,
Simon Fraser University, Burnaby, Canada, June 15, 1995,
*"Quadrangulations of Planar Sets."* - Geometry Seminar, Courant
Institute of Mathematical Sciences, New York University, New York, April
25, 1995,
*"Quadrangulations of Planar Point Sets"*

- Computing Science Seminar,
School of Computing Science, Simon Fraser University, Burnaby, Canada,
September 2, 1994,
*"Where Should You Sit in the Cinema so That Your Favorite Actor is as Tall as Possible?"* - GINTIC Institute of Manufacturing
Technology, Nanyang Technological University, Singapore, July 11, 1994,
*"Geometric and Computational Aspects of Manufacturing Processes."* - Seminar, Department of Computer
Science, National University of Singapore July 12, 1994,
*"Where Should You Sit in the Cinema so That Your Favorite Actor is as Tall as Possible?"* - Seminar, Department of Computer
Science, University of Newcastle Australia, July 14, 1994,
*"Geometric and Computational Aspects of Manufacturing Processes."* - Seminar, Department of Computer
Science, University of Newcastle Australia, July 15, 1994,
*"A New Look at Euclid's Second Proposition."* - Seminar, Department of Mathematics,
University of Nevada at Reno, April 15, 1994,
*"A New Look at Euclid's Second Proposition."* - Seminar, Department of Electrical
Engineering, University of Nevada at Reno, April 15, 1994,
*"Geometric and Computational Aspects of Manufacturing Processes."* - Seminar, Department of Computer
Science, Howard R. Hughes College of Engineering, University of Nevada
at Las Vegas, April 13, 1994,
*"Geometric and Computational Aspects of Manufacturing Processes."*

- Mechanical Engineering Department,
Ecole Politechnique, University of Montreal, November 15, 1993,
*"Computational Geometric Problems Related to Injection Molding."* - Mathematics & Computer
Science Colloquium, University of Vermont, Burlington, Vermont, November
12, 1993,
*"Movable Separability of Objects in Two and Three Dimensions."* - Mathematics & Computer
Science Seminar, Middlebury College, Vermont, October 12, 1993,
*"Movable Separability of Objects in Two and Three Dimensions."* - Geometry Seminar, Department
of Computer Science, Utrecht University, June 29, 1993,
*"Geometric and Computational Aspects of Injection Molding and Stereolithography."* - Pattern Recognition Colloquium,
Department of Physics, Delft University of Technology, June 28, 1993,
*"Geometric and Computational Aspects of Injection Molding and Stereolithography."* - Department of Applied Mathematics
II, Universidad Politecnica de Catalunya, Barcelona, Spain, June 17, 1993,
*"Aspectos Geometricos y Computacionales de la Inyección en Moldes y de la Estereolitografia."* - Department of Applied Mathematics,
Universidad Politecnica de Madrid, Spain, June 10, 1993,
*"Arreglos de Rectas."* - Seminar, Faculty of Mathematics
and Computer Science, University of Amsterdam, May 28, 1993,
*"Approximating Polygonal Curves in Two and Three Dimensions."*

- Seminar, Department of Mathematics,
City University of New York, York College, Jamaica, N.Y., September 25,
1992,
*"Separability of Sets of Objects in Two and Three Dimensions."* - Seminar, Department of Computer
Science, York University, North York, Ontario, September 15, 1992,
*"Separability of Sets of Objects in Two and Three Dimensions."* - Colloquium, Department of
Mathematics and Computer Science, University of Tulsa, Okla., July 14,
1992,
*"Separability of Sets of Objects in Two and Three Dimensions."* - The Guillermo Torres Seminar
on Topology and Geometry, Institute of Mathematics, Universidad Nacional
Autónoma de México, México City, June 25, 1992,
*"Separabilidad de Objetos Mediante Translaciones en dos y tres Dimensiones."* - Research Seminar, Department
of Applied Mathematics II, Universidad Politecnica de Catalunya, Barcelona,
June 8, 1992,
*"Open Problems in Computational Geometry."* - Seminar on Software Mathematics
and Computational Mathematics, Department of Applied Mathematics II, Universidad
Politecnica de Catalunya, Barcelona, June 5, 1992,
*"Separabilidad de Objetos Mediante Movimientos en el Plano y el Espacio Tridimensional."* - Colloquium, Department of
Mathematics, Universidad Politecnica de Madrid, June 4, 1992,
*"Separabilidad de Objetos Mediante Movimientos en el Plano y el Espacio Tridimensional."* - Research Seminar, Department
of Mathematics, Universidad Politecnica de Madrid, June 3, 1992,
*"Computational Geometry at McGill University."* - Colloquium, Department of
Mathematics and Computer Science, University of Quebec in Montreal, May
7, 1992,
*"Movable Separability of Sets in Two and Three Dimensions."* - Mathematics Colloquium, Departments
of Mathematics, Statistics, Computer Science and Electrical Engineering,
University of Vermont, Burlington, Vermont, USA, April 10, 1992,
*"A New Look at Euclid's Second Proposition."* - Seminar, McGill Research Center
for Intelligent Machines, McGill University, Montreal, Canada, January
29, 1992,
*"Movable Separability of Objects in Two and Three Dimensions."* - Seminar, McGill Research Center
for Intelligent Machines, McGill University, Montreal, Canada, January
22, 1992,
*"The Use of Proximity Graphs in Pattern Recognition."*

- Computer Science Seminar,
Division of Computer Science, Asian Institute of Technology, Bangkok, Thailand,
January 8, 1991,
*"Polygonal Approximation of Curves and Applications."* - Information Science Seminar,
Institute of Information Science, Academia Sinica, Taipei, Taiwan, Republic
of China, December 19, 1991,
*"Computing Shortest Transversals of Sets."* - Seminar, Ottawa-Carleton Institute
for Computer Science, Carleton University, November 7, 1991,
*"Computing Geometrical Properties of Arrangements of Lines."* - Séminaire en Informatique,
Département d'Informatique, Université du Québec at
Hull, November 6, 1991,
*"Computing Geometrical Properties of Arrangements of Lines."* - Seminar on the History and
Philosophy of Science, Department of Psychology, McGill University, September
30, 1991,
*"The Role of Visual and Kinesthetic Thinking in Geometry."* - Distinguished Seminar Series,
Sesquicentennial Anniversary of Queens University, Department of Computing
and Information Science, Kingston, Ontario, April 18, 1991,
*"A New Look at Euclid's Second Proposition."* - Distinguished Lecture Series,
225th Anniversary of Rutgers University, Computer Science Department Colloquium,
New Brunswick, New Jersey, April 1st, 1991,
*"Computing Shortest Transversals of Sets."* - Colloquium, University of
Waterloo, Department of Computer Science, Waterloo, March 22, 1991,
*"Computing Shortest Transversals of Sets."* - C & O Seminar, University
of Waterloo, Department of Combinatorics and Optimization, Waterloo, March
21, 1991,
*"A New Look at Euclid's Second Proposition."* - Colloquium, University of
Nevada at Las Vegas, Department of Computer Science, January 28, 1991,
*"Computing Shortest Transversals of Sets."*

- Colloquium, Simon Fraser University,
Department of Computer Science, Burnaby, November 30, 1990,
*"A New Look at Euclid's Second Proposition."* - Colloquium, Simon Fraser University,
Department of Computer Science, Burnaby, June 1, 1990,
*"Computing Geometric Properties of Arrangements.*

- Colloquium, Ohio State University,
Department of Computer and Information Science, Columbus, November 2, 1989,
*"Computing Minimal Spanning Covers of Sets.*" - Colloquium, University of
Amsterdam, Department of Computer Science, Amsterdam, July 6, 1989,
*"Determining Weak External Visibility of a Polygon."* - Colloquium, University of
Amsterdam, Department of Computer Science, Amsterdam, July 6, 1989,
*"Computing Geodesic Properties of Polygons."* - Colloquium, University of
Amsterdam, Department of Computer Science, Amsterdam, June 22, 1989,
*"A Hierarchy of Polygons That Admit Linear-Time Triangulation."* - Colloquium, University of
Amsterdam, Department of Computer Science, Amsterdam, June 22, 1989,
*"An Output-Complexity-Sensitive Polygon Triangulation Algorithm."* - Colloquium, University of
Amsterdam, Department of Computer Science, Amsterdam, June 15, 1989,
*"Separating Two Simple Polygons by a Single Translation."* - Colloquium, University of
Amsterdam, Department of Computer Science, Amsterdam, June 1, 1989,
*"Determining Edge-to-Edge Visibility in a Polygon."* - Colloquium, University of
Amsterdam, Department of Computer Science, Amsterdam, June 1, 1989,
*"Computing Distances Between Sets."* - Colloquium, University of
Amsterdam, Department of Computer Science, Amsterdam, May 25, 1989,
*"Computing the Convex Hull of a Set."* - Colloquium, University of
Amsterdam, Department of Computer Science, Amsterdam, May 25, 1989,
*"Computing the Diameter of a Set."* - Colloquium, University of
West Indies, Department of Mathematics, Cave Hill, Barbados, February 22,
1989,
*"A Hierarchy of Polygons That can be Triangulated in Linear Time"* - Colloquium, University of
West Indies, Department of Mathematics, Cave Hill, Barbados, February 15,
1989,
*"An Output-Complexity Sensitive Polygon Triangulation Algorithm."*

- Colloquium, Algorithms Group
Seminar, Simon Fraser University, School of Computing Science, Burnaby,
November 25, 1988,
*"On Determining the Weak Visibility of a Polyhedral Terrain From a Line."* - Colloquium, University of
Washington, Department of Computer Science, Seattle, October 19, 1988,
*"On Triangulating Simple Polygons."* - Colloquium, University of
British Columbia, Department of Computer Science, Vancouver, September
29, 1988,
*"On Triangulating Simple Polygons."* - Colloquium, University of
Victoria, Computer Science Department, Victoria, September 16, 1988,
*"On Triangulating Simple Polygons."* - DARTS Lecture (Distinguished
Advanced Research and Technology Seminar) Simon Fraser University, School
of Engineering Science, Burnaby, September 15, 1988,
*"Computational Geometry and Robotics."* - Colloquium, Simon Fraser University,
School of Computing Science, Burnaby, August 10, 1988,
*"On Triangulating Simple Polygons."*

- University of Tokyo, Computer
Science Department (c/o Prof. Kunii), Sept. 3, 1987,
*"Relative Convex Hulls of Sets and their Applications."* - Simon Fraser University, Computer
Science Department, Vancouver, August 28, 1987,
*"Relative Convex Hulls of Sets and their Applications."* - Carleton University, School
of Computer Science, Ottawa, October 30, 1987,
*"Relative Convex Hulls of Sets and their Applications."*

- Computer Science Seminar,
Carleton University, Ottawa, Canada, February 28, 1985,
*"Some Collision Avoidance Problems in the Plane."*

- Computer Science Colloquium,
University of Maryland, College Park, U.S.A., April 26, 1984,
*"Some Collision Avoidance Problems in the Plane."*

- Computer Science Colloquium,
Kyoto University, Kyoto, Japan, December 26, 1983,
*"Some Collision Avoidance Problems in the Plane."* - Electrical, Engineering Colloquium,
University of Nagoya, Japan, December 29, 1983,
*"Some Collision Avoidance Problems in the Plane."* - Mathematical Engineering Colloquium,
University of Tokyo, Japan, December 16, 1983,
*"Some Collision Avoidance Problems in the Plane."* - Computer Science Colloquium,
Concordia University, Montreal November 1983,
*"Some Collision Avoidance Problems in the Plane."* - Systems Science Colloquium,
University of Toronto, February 1983,
*"Recent Results in Computational Geometry."*

- Psychology Colloquium, Carleton
University, Ottawa, October 18, 1982,
*"The Computation and Perception of Shapes."* - Mathematics Colloquium, University
of Genova, Italy, June 1982,
*"Efficient Algorithms for Computing Distances Between Sets."* - Computer Science Colloquium,
University of Torino, Italy, June 1982,
*"Efficient Algorithms for Computing Distances Between Sets."*

- Colloquia Estria, Département
de Mathématiques et d'informatique, Université de Sherbrooke,
26 mars, 1981,
*"Problèmes en Géométrie Algorithmique,"*

- Computer Science Seminar,
University of British Columbia, Vancouver, Feb. 6, 1981,
*"Pattern Recognition and Geometrical Complexity."*

- Computing and Information
Science Seminar, Queen's University, Kingston, Ontario, November 5, 1980,
*"Pattern Recognition and Geometrical Complexity."* - Computing and Information
Science Seminar, Queen's University, Kingston, Ontario, March 26, 1980,
*"The Relative Neighborhood Graph of a Finite Planar Set."*

- Séminaire d'Informatique
Heuristique, Université de Paris, (Pierre et Marie Curie), June
11, 1979,
*"Pattern Recognition and Geometrical Complexity: Placing an Elastic Band Around a Group of Pegs."* - Systems Theory Seminar, University of Louvain (La Neuve),
Belgium, June 8, 1979,
*"Pattern Recognition and Geometrical Complexity: Placing an Elastic Band Around a Group of Pegs."* - Electrical Engineering Seminar, Delft University of Technology,
The Netherlands, June 5, 1979,
*"Using Contextual Information to Improve the Performance of Character Recognition Machines."* - Department of Applied Physics Seminar, Delft University
of Technology, The Netherlands, June 1, 1979,
*"Pattern Recognition and Geometrical Complexity: Placing an Elastic Band Around a Group of Pegs."*

- Computer Science Colloquium,
University of Connecticut, October 13, 1978,
*"The Convex Hull as a Tool in Pattern Recognition."* - Computing Center and Computer
Science Colloquium, State University of New York at Buffalo, October 6,
1978,
*"The Convex Hull as a Tool in Pattern Recognition."*

- University of Montreal, April
1st, 1976,
*"Using Contextual Information to Improve the Performance of Character Recognition Machines."*

- Clarkson College of Technology,
December 4, 1975,
*"Using Contextual Information to Improve the Performance of Character Recognition Machines."* - Department of Electrical Engineering,
McGill University, March 13, 1975,
*"The Use of Statistical Language Constraints in Machine Recognition of Hand Printed English Text."*

- Computer Science Department, Simon Fraser University, Spring, 1974, "The Use of Statistical Language Constraints to Improve the Performance of Character Recognition Machines."

- Département d'Informatique, Université de Montreal, Spring, 1973, "Distance Measures as Measures of Certainty and Their Application to Pattern Recognition."

- INRIA, Sophia-Antipolis, France,
July 26, 1996,
*"Removing Degeneracies in Computational Geometry."* - IBM Software Solutions Toronto
Laboratory, The Centre for Advanced Studies, North York, Ontario, December
10, 1993,
*"Geometric and Computational Aspects of Manufacturing Processes."* - Bell Northern Research, Nun's
Island, Montreal, May 12, 1993,
*"The Application of Proximity Graphs to Edited Nearest Neighbor Decision Rules."* - I.B.M. Thomas J. Watson Research
Center, Yorktown Heights, N.Y., May 29, 1992,
*"Computing Geometric Properties of Arrangements of Lines and Line Segments."* - Nippon Telegraph and Telephone
Corporation, Autonomous Robot Systems Laboratory, Tokyo, December 5, 1990,
*"Computational Geometric Aspects of Visibility."* - MacDonald, Dettwiler &
Associates, Richmond, B.C., November 9, 1988,
*"Computational Geometry and Geographic Information Systems."* - Hitachi Central Research Laboratory,
Tokyo, Japan, December 22, 1983,
*"Some Collision Avoidance Problems in the Plane."* - Bell Northern Research, Nun's
Island, Verdun, October 29, 1982,
*"Graph-theoretic Methods for Edited Nearest Neighbor Decision Rules,"*

- Herzliah High School, invited
speaker at the awards-ceremonies of the First Montreal High-School Computer
Programming Competition, May 3, 1981,
*"Computer Applications in Artificial Intelligence."*