Seminar

Wednesday, August 29, 2018 1:30 pm - 1:30 pm EDT (GMT -04:00)

Seminar • Algorithms and Complexity — Counting Subwords and Regular Languages

Finn Lidbetter, Master’s candidate
David R. Cheriton School of Computer Science

Let x and y be words. We consider the languages whose words z are those for which the numbers of occurrences of x and y, as subwords of z, are the same (resp., the number of x's is less than the number of y's, resp., is less than or equal). In this talk we will give a necessary and sufficient condition on x and y for these languages to be regular, and we show how to check this condition efficiently. 

Irfan Ahmad, Founder and CEO
CachePhysics

Caches in modern distributed and storage systems must be manually tuned and sized in response to changing application’s workload. A balance must be achieved between cost, performance and revenue loss from cache sizing mis-matches. However, caches are inherently nonlinear systems making this exercise equivalent to solving a maze in the dark.

Kshitij Jain, Master’s candidate
David R. Cheriton School of Computer Science

We introduce a problem called the Minimum Shared-Power Edge Cut (MSPEC). The input to the problem is an undirected edge-weighted graph with distinguished vertices s and t, and the goal is to find an s-t cut by assigning "powers'' at the vertices and removing an edge if the sum of the powers at its endpoints is at least its weight. The objective is to minimize the sum of the assigned powers.

Philipp Kindermann, Postdoctoral Fellow
David R. Cheriton School of Computer Science

The visual complexity of a graph drawing is defined as the number of geometric objects needed to represent all its edges. In particular, one object may represent multiple edges, e.g., one needs only one line segment to draw two collinear incident edges.