Abstract: Ambient assisted living (AAL) is a newly emerging term describing a research area with focus on services that support people in their daily life with particular focus on elderly people. This includes reminding and alerting the assisted person(s) and their environment, giving feedback, advice, and impulses for physical, or social activities, among others. All of these supportive actions need to be context-aware. Semantic technologies have been considered to be a perfect fit for context-awareness in pervasive computing and ambient intelligence. Mainstream semantic (web) technologies are nowadays largely based on description logics and the W3C standard OWLDL (c.f. [WZGP04], [DB08], [PVdBW+ 04], and [ESB07]), which are also used in the AAL domain (see [PG07] and [KC06]). The analysis of the scenarios and use cases, however, have yielded requirements and constraints, which have shown that these mainstream technologies are not well-suited for the AAL domain. In this paper we prese...