A script-based approach to distributed presence aggregation

Personal presence systems are widely used to get aware of other users' availability and willingness to communicate before actually contacting them. After early systems focused on ad-hoc text messaging only and relied on manual updates of status descriptions, modern applications not only integrate multimedia communication but also facilitate automatic detection of status changes. The status of devices owned by a particular user then can be used to infer the user's presence status automatically, i.e. without explicit user-interaction. To achieve this, unstructured data provided from various sources is aggregated and set into relation with user-specific context information. The aggregation service presented here eliminates the need for extensive information acquisition that is necessary for most learning algorithms. Users instead have full control over the aggregation process, including the distribution of their presence status information to interested watchers.