Location Techniques -- Audio Location: Accurate Low-Cost Location Sensing -- Using Sound Source Localization in a Home Environment -- Tracking Locations of Moving Hand-Held Displays Using Projected Light -- Activity and Context -- Bathroom Activity Monitoring Based on Sound -- Simultaneous Tracking and Activity Recognition (STAR) Using Many Anonymous, Binary Sensors -- Enhancing Semantic Spaces with Event-Driven Context Interpretation -- The Java Context Awareness Framework (JCAF) – A Service Infrastructure and Programming Framework for Context-Aware Applications -- Location and Privacy -- Place Lab: Device Positioning Using Radio Beacons in the Wild -- Social Disclosure of Place: From Location Technology to Communication Practices -- A Formal Model of Obfuscation and Negotiation for Location Privacy -- Handheld Devices -- A Conceptual Framework for Camera Phone-Based Interaction Techniques -- u-Photo: Interacting with Pervasive Services Using Digital Still Images -- Towards Massively Multi-user Augmented Reality on Handheld Devices -- Sensor Systems -- Design Methodology for Context-Aware Wearable Sensor Systems -- Collaborative Sensing in a Retail Store Using Synchronous Distributed Jam Signalling -- Parasitic Mobility for Pervasive Sensor Networks -- User Interaction -- Decision-Theoretic Planning Meets User Requirements: Enhancements and Studies of an Intelligent Shopping Guide -- Integrating Intra and Extra Gestures into a Mobile and Multimodal Shopping Assistant -- AwareMirror: A Personalized Display Using a Mirror -- Embedded Assessment: Overcoming Barriers to Early Detection with Pervasive Computing.WelcometotheproceedingsofPervasive2005,The3rdInternationalConference on Pervasive Computing. We were honored to serve as chairs in this conference series, which was founded in 2002 and is now emerging as one of the most respected venues for publication of research on pervasive and ubiquitous c- puting. The conference is attracting research submissions of very high quality from all over the world, and from researchers representing a variety of disciplines and perspectives. We thank everybody who submitted their papers to Pervasive, demonstrating the extensive work going on in this area; and the Program C- mittee and our external reviewers who spent countless hours providing feedback and guidance in order to create the ?nal program. This year we received 130 submissions. By the end of the review process, we had 566 reviews on ?le, as well as long email discussion threads for each paper. In an initial phase we had each paper reviewed by two members of the Program Committee and two external reviewers. In a second phase, each paper wasdiscussedbyitsfourreviewerstoreachconsensusastoitstechnicalmerit. At the end of this phase, the top-rated papers as well as those that were found to be most controversial were selected for discussion at the PC meeting and reviewed by an additional PC member. The result being that each paper discussed in the PC meeting had 5 reviews and was read by three people who participated in the meeting, leading to a very informed and lively discussion.