The following is the schedule of upcoming department seminars. Seminars will be added to the schedule throughout the year. All seminars are free of charge and are open to all members, affiliates, and colleagues of the university community. Seminars are typically held on Tuesday or Thursday at 1:00 pm. If you would like additional information or if you might be interested in presenting a seminar, please contact Avery Miller or the Department of Computer Science.

David Kirkpatrick
When: November 23, 2017 @ 1:00pm
Where: EITC E2304Title: Minimizing uncertainty in the proximity of moving agents
Speaker: Dr. David Kirkpatrick, Department of Computer Science, University of British Columbia
Abstract:
Search problems are conventionally understood in terms of minimizing uncertainty in the location of one or more agents (perhaps moving in an adversarial fashion), using some form of spatial queries. We consider, and encourage further consideration of, a natural modification in which the goal is to reduce uncertainty, attributable to unmonitored motion, concerning the proximity, rather than absolute location, of a collection of moving agents.
For example, imagine a collection of point agents moving in a graph (or some subset of one, or higher,dimensional Euclidean space) each with some (known, but possibly different) upper bound on their speed. If we know, by means of an individual location query, the precise location of an individual agent at a particular time, then its location, until the time that it is next queried, lies in a steadilyexpanding region of uncertainty. Motivated by the fact that resource demands are often commensurate with congestion (e.g. bandwidth allocation), we consider the problem of minimizing measures of potential congestion—maximum local congestion, over all agent configurations consistent with the current uncertainty of the collection—using individual queries that are restricted to one query per unit of time.
Our focus to date has been on the degree of the uncertainty regions (defined as the maximum, over all agents a, of the number of uncertainty regions that intersect the uncertainty region of a), a natural measure of worstcase congestion, for point agents moving continuously in one, or higher,dimensional Euclidean space. The goal is to minimize this degree continuously. Competitive query strategies are described in terms of a notion of intrinsic degree (the minimum degree achievable by any query strategy, even one that knows the trajectories of all agents). Only partially studied to date are analogous questions for agents moving in a graph.
(Based on joint work with Daniel Busto, and Will Evans)

Erin Chambers
When: November 28, 2017 @ 1:00pm
Where: EITC E2304Title: Burning the Medial Axis
Speaker: Dr. Erin Chambers, Department of Computer Science, Saint Louis University
Abstract:The medial axis plays a fundamental role in many shape matching and analysis, but is widely known to be unstable to even small boundary perturbations. Methods for pruning the medial axis are usually guided by some measure of significance, with considerable work done for both 2 and 3 dimensional shapes. However, the majority of significance measures over the medial axis are locally defined, and hence are unable to recognize more global topological features, or are difficult to compute and sensitive to perturbations on the boundary. In this talk, I will present recent work done in 2d and 3d to compute a new significance measure on the medial axis, which we call the burn time function. Using this function, we are able to generalize the classical notion of erosion thickness measure over the medial axes of 2D shapes. We demonstrate the utility of these shape significance measures in extracting clean, shaperevealing and topologypreserving skeletons in 2 and 3D which are robust to noise on the boundary. To conclude, I will also discuss future directions and applications of this work.(This talk is based on prior joint work with Tao Ju, David Letscher, Lu Liu, Kyle Sykes, and Yajie Yan.)