In order to deliver relevant information at the right time to its mobile users, systems such as event notification systems need to be aware of the users’ context, which includes the current time, their location, or the devices they use. Many context frameworks have been introduced in the past few years. However, they usually do not consider the notion of characteristic features of contexts that are invariant during certain time intervals. Knowing the current situation of a user allows the system to better target the information to be delivered. This paper presents a model to handle various contexts and situations in information logistics. A context is defined as a collection of values usually observed by sensors, eg., location or temperature. A situation builds on this concept by introducing semantical aspects defined in an ontology. Our
proposal has been tested in two projects.