Dr. Wei Wei teaches in the computer science dept. He has significant experience in the telecom world as an architect. He will be giving a talk on an interesting unsolved problem in telecommunications. It deals with the simplest technology: ethernet. This is a crude-but-cheap small network where everyone shares a physical wire. Any time someone wants to send a message to another station on the network, they first have to acquire the line. Unfortunately, sometimes (often if it's busy) more than one sender tries to grab the wire at the same time. ("Same" is reasonably well defined, as they all share a basic clock rhythm, so the times are effectively discrete.)

When that happens, they each have to decide how long to wait before trying again. It's no good trying right away - or at least, not always right away - or they will clash forever. Like people on the sidewalk, who keep moving aside for the other, so they never get past each other (or at least it takes a while to sort it out). So they pick a time at random for how long to wait. The classical algorithm has a fairly crude way to pick this time, and it gets exponentially longer for each failure in a row. The unsolved problem is how each sender can pick a time to wait so that they don't wait too long, and clashes are avoided as much as possible. Should be interesting - a nice discrete unsolved and useful problem.

Special further attraction: Free Pizza! (We may ask for small voluntary donations .)

When: Wednesday March 3rd, at 3:30. (We will probably start a few minutes late, which will make it 3/3 3:33...)

Where: Student Union SU 2.502 (Pegasus) Map