Aaron Blankstein will present his Pre FPO on Tuesday, February 7, 2017 at 10am in CS 302. The members of his committee are as follows: Readers: Michael Freedman (adviser), Jennifer Rexford, and Nick Feamster; Non-Readers: Robert Tarjan and Kyle Jamieson Everyone is invited to attend his talk. The talk abstract follows below. Abstract: In my thesis, I will show how, in many respects, modern web applications are built with implicit structure, such that several classic problems in computer systems can be tackled in new ways allowing applications to reap security and performance benefits. I will apply this thesis in two separate contexts. In the first, I will look at the problems of providing some automatic security to web applications by partitioning the server-side code of the application, isolating those partitions, learning access control policies for those partitions, and extending this isolation to front-end code with javascript sandboxing. In the second, I will look at how modern web applications interact with application caches, and develop a family of cache eviction policies tailored to these needs by focusing on prioritizing individual items to capture how item request frequencies, associated costs, and expiration times affect cache performance.