Ubiquitous computing, with a dramatic increase in the event monitoring capabilities of wireless devices and sensors, requires more complex temporal and spatial resolution in event correlation. In this chapter, we describe two aspects of event correlation to support such environments: event modelling including spatio-temporal information, and composite event semantics with interval-based semantics for efficient indexing, filtering, and matching. It includes a comparative study of existing event correlation work. The described durative event model, combined with interval-semantics, provides a new vision for data processing in ubiquitous computing. This makes it possible to extend the functionality of simple publish/subscribe filters to stateful subscriptions, parametrisation, and computation of aggregates, while maintaining high scalability.