AI Seminar Series 2021: Levi Lelis

The AI Seminar is a weekly meeting at the University of Alberta where researchers interested in artificial intelligence (AI) can share their research. Presenters include both local speakers from the University of Alberta and visitors from other institutions. Topics can be related in any way to artificial intelligence, from foundational theoretical work to innovative applications of AI techniques to new fields and problems.

On July 23, Amii Fellow and Canada CIFAR AI Chair Levi Lelis, presented “Policy and Heuristic-Guided Tree Search Algorithms" at the AI Seminar.

Heuristic search algorithms such as A* use a heuristic function to guide its search by focusing on states that are estimated to be closer to a goal state. In this talk, Levi explores the use of a policy, i.e., a probability distribution over actions, for solving single-agent deterministic problems by:

• described Levin tree search, an algorithm that uses a policy and offers guarantees on the number of nodes it needs to expand to solve state-space search problems.
• discussed Policy-Guided Heuristic Search (PHS), a search algorithm that uses both a policy and a heuristic function to guide its search.
• presented empirical results showing the advantages of policy-guided tree search algorithms, especially when it is difficult to learn effective heuristic functions to guide the search.

Watch the full presentation below:

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