COMBINATORIAL ALGORITHMS GROUP Schedule of Talks: Summer 2011 |
If you would like to give a talk in our seminar series, please contact Wendy Myrvold (wendym@cs.uvic.ca). To get e-mail notification of our seminars and other events, you can subscribe to the CAG e-mail list at http://mailman.csc.uvic.ca/mailman/listinfo/cag
Date | Place | Time | Speaker | Abbreviated Title |
---|---|---|---|---|
Fri. May 6 | ECS 660 | 2:30pm | Dimitri Marinakis | Stochastic Scheduling for Underwater Sensor Networks |
Fri. May 6 | ECS 660 | 3:00pm | Wendy Myrvold | Searching for three MOLS of order 10 |
Fri. May 28 | _ | _ | No CAG. | CanaDAM Conference, May 31-June 3 |
Fri. June 24 | _ | _ | No CAG. | IWOCA Conference, June 20-June 22 |
Tues. Aug. 23 | SSM A102 | 3:30pm | Andreas Brandstädt | On Variants of Matchings |
For our first week, we have a 1.5 hour double feature which includes two talks.
The context of underwater sensor networks (UWSNs) presents special challenges for data transmission. For that context, we examine the merit of using a simple, stochastic transmission strategy based on the ALOHA protocol. The strategy uses a stochastic scheduling approach in which time is slotted, and each network node broadcasts according to some probability during each time slot. We present a closed-form solution to an objective function that guides the assignment of the broadcast probabilities with respect to overall network reliability. We propose an easily distributed heuristic based on local network density and evaluate our approach using numerical simulations. The evaluation results show that even without using explicit control signalling, our simple stochastic scheduling method performs well for data transmission in UWSNs.
A Latin square of order n is a n \times n array of n symbols such that each symbol appears exactly once in each row and exactly once in each column. Two Latin squares of order n are orthogonal if when superimposed, each ordered pair of symbols occurs exactly once. One of the big unsolved problems in design theory is to determine if it is possible to find three or more pairwise orthogonal Latin squares of order 10. This talk describes both theoretical and computational attempts at resolving this question. The talk will conclude with some suggestions for promising areas for continued search.
The research presented in this talk was done in collaboration with Erin Delisle, Mark Ellingham, Leah Howard, Nikolay Korovaiko, Brendan McKay, Alison Meynert, and Ian Wanless.