  We introduce and address the problem of ad hoc table retrieval: answering a
keyword query with a ranked list of tables. This task is not only interesting
on its own account, but is also being used as a core component in many other
table-based information access scenarios, such as table completion or table
mining. The main novel contribution of this work is a method for performing
semantic matching between queries and tables. Specifically, we (i) represent
queries and tables in multiple semantic spaces (both discrete sparse and
continuous dense vector representations) and (ii) introduce various similarity
measures for matching those semantic representations. We consider all possible
combinations of semantic representations and similarity measures and use these
as features in a supervised learning model. Using a purpose-built test
collection based on Wikipedia tables, we demonstrate significant and
substantial improvements over a state-of-the-art baseline.
