Context awareness is one of the important fields in ubiquitous computing.
Smart Home, a specific instance of ubiquitous computing, provides every family
with opportunities to enjoy the power of hi-tech home living. Discovering that
relationship among user, activity and context data in home environment is
semantic, therefore, we apply ontology to model these relationships and then
reason them as the semantic information. In this paper, we present the
realization of smart home's context-aware system based on ontology. We discuss
the current challenges in realizing the ontology context base.