Talks and presentations

Learning near-optimal robust solutions in pricing and beyond

October 18, 2022

Conference Presentation, 2022 INFORMS Annual Meeting, Indianapolis, IN

We develop a method for producing robust decisions in predict-optimize tasks. In particular, we introduce two notions of robustness: (1) decisions which minimize maximum cost with respect to noise/uncertainty in the objective, (2) producing stable decisions which do not change significantly under perturbation to the training data.

Online semigroup queries on arrays and paths on trees

September 30, 2022

Seminar, MIT Operations Research Center Student Seminar, Cambridge, MA

We consider a common class of database range queries which consists of evaluating a given function on contiguous subranges of arrays. For instance, this may be the average or minimum of a range. Such queries are also common subroutines in various algorithms. A common approach to tackling the range query problem for semigroup operators is to precompute the answer for a small subset of ranges, and combine these solutions when answering any given query. For instance, the sum of the elements from index i to index j can be computed as the answers to the ranges from i to k and k+1 to j for i <= k < j. This introduces an inherent tradeoff between the precomputation complexity and the query complexity - the more precomputation, the less query time required. Moreover, we consider a data-driven case and design a method to make better precompuation decisions than traditional methods.