Applications -- FireGuide: A Context-Aware Fire Response Guide for the Building Occupants -- How to Log Sleeping Trends? A Case Study on the Long-Term Capturing of User Data -- Utilizing Social Context for Providing Personalized Services to Mobile Users -- Sensing -- Activity Recognition Using Biomechanical Model Based Pose Estimation -- Energy Efficient Cooperative Multimodal Ambient Monitoring -- On the Use of Magnetic Field Disturbances as Features for Activity Recognition with on Body Sensors -- Systems Support -- Feature Weighting for CPM-Based Context Validation -- A Formal Model of Reliable Sensor Perception -- Effect of Caching in a Broker Based Context Provisioning System -- A Logic Based Context Query Language -- Higher Level Modeling -- Sensor Abstractions for Opportunistic Activity and Context Recognition Systems -- Identifying Important Action Primitives for High Level Activity Recognition -- A Resource Model for the Real World Internet -- Report on the Workshop on ICT and Ageing: Announcing the European Initiative for an Ambient Assitant Living (AAL) Platform -- Platforms for AAL Applications.