In my research, I study the problem of representating commonsense
knowledge: that is, the problem of taking the basic knowledge about
the real world that is common to all humans; expressing it in
a form that is systematic enough to be used by a computer program;
and providing the program with techniques for effectively using that
knowledge. My work has focussed primarily on spatial and physical reasoning,
but I have also looked at reasoning about knowledge, belief, plans, and goals,
and its interaction with physical reasoning.