CGL Meeting Agenda - 2000.01.12

January 19th, 2000

Location:
DC 1304
Time:
11:30 a.m.
Chair:
Bill Cowan 
Member List

1. Adoption of the Agenda - additions or deletions

2. Coffee Hour

Coffee hour this week:
Blair
Coffee hour next week:
None.

3. Next meeting

Date:
Wednesday, January 19th, 2000
Location:
DC1304
Time:
11:30 a.m.
Chair:
Rojia Dadashzadeh (January 26th) 
Technical presentation:
Blair Conrad (January 26th) 

4. Forthcoming

Chair:
  1. Margaret Dulat (February 2nd) 
  2. Eric Demaine (February 9th) :-)
  3. Roger Fernandes (February 16th) 
Tech Presenters:
  1. Bill Cowan  (February 2nd)
  2. Eric Demaine (February 9th) :-)
  3. Rojia Dadashzadeh (February 16th) 

5. Technical Presentation

Presenter: Shalini Aggarwal (January 19th) 
Shalini Aggarwal (January 19th) 
Title:
Two-Handed Input in a Compound Task
Abstract:

Kabbash, Buxton, and Sellen contend that a certain class of two-handed techniques can result in significantly improved performance without imposing drawbacks such as additional cognitive load. To examine this, we look at four interaction techniques that have been studied in the context of a compound drawing/color-selection task --- a unimanual technique, a bimanual technique where each hand controls independent subtasks, and two asymmetrically dependent bimanual techniques. As predicted, one of the techniques, Toolglass, which conforms most closely to everyday bimanual tasks as described by Guiard's principles, does give rise to significantly improved performance over one-handed techniques. In other cases, two hands prove to be worse than one.

6. General Discussion Items

7. Action List

8. Director's Meeting (last week's)

  1. Blair's Replacement
  2. Surplus Ultrixes
  3. Winzip for PCs

9. Seminars

Wednesday, 19 January 2000, 3:30PM -- DC1304
Algorithms and Complexity Group Seminar -- Computer Science
Speaker: Erik D. Demaine, Dept. of Computer Science, University of Waterloo
Title: "Convexifying Polygons and Straightening Polygonal Arcs"
Abstract: We prove, together with Robert Connelly and Guenter Rote, that any simple polygon in the plane can be continously moved, while preserving the length of each edge and keeping the polygon simple, to bring it to a convex polygon. In particular, this settles the carpenter's ruler problem posed by several researchers including Joseph Mitchell, Bill Lenhart and Sue Whitesides: every polygonal arc (simple open chain) can be straightened while preserving the edge lengths and maintaining simplicity. More generally, we prove that a simple planar linkage consisting of arcs and cycles of rigid bars joined at incident endpoints can be continuously reconfigured so that the arcs exterior to all cycles become straight, the cycles exterior to all cycles become convex, and no bars cross while preserving the bar lengths. Furthermore, our motion does not decrease the distance between any pair of vertices.

Friday, 21 January 2000, 1:00PM -- Math & Computer, Room 5136
Seminar -- Combinatorics and Optimization
Speaker: Kenneth J. Giuliani, Dept. of Combinatorics & Optimization, University of Waterloo
Title: "Graduate Student Seminar - A Brief History of Cryptography"
Abstract: Although cryptography is regarded as a modern discipline, it can be argued that, in some forms, it dates as far back as classical antiquity. It became an essential tool to the Allied effort during World War II, before really evolving in the mid-1970's.

In this talk, I intend to introduce the basic concept of cryptography and go through some of the highlights of its history. The talk will not be overly technical, instead focussing on the history.

10. Lab Cleanup