Welcome to the proceedings of UbiComp 2004. In recent years the ubiquitous computing community has witnessed a sign- cant growth in the number of conferences in the area, each with its own disti- tive characteristics. For UbiComp these characteristics have always included a high-quality technical program and associated demonstrations and posters that cover the full range of research being carried out under the umbrella of ubiq- tous computing. Ours is a broaddiscipline andUbiComp aims to be aninclusive forum that welcomes submissions from researchers with many di?erent ba- grounds. This year we received 145 submissions. Of these we accepted 26, an acceptance rate of just under 18%. Of course acceptance rate is simply a m- sure of selectivity rather than quality and we were particularly pleased this year to note that we had a large number of high-quality submissions from which to assemble the program for 2004. The broad nature of ubiquitous computing research makes reviewing Ubi- Comp submissions a particular challenge.
This year we adopted a new process for review and selection that has, we hope, resulted in all authors obtaining - tremely detailed feedback on their submission whether or not it was accepted for publication. We believe the process enabled us to assemble the best pos- ble program for delegates at the conference. If you submitted a paper, we hope that you bene?ted from the feedback that your peers have provided, and if you attended UbiComp 2004 we hope that you enjoyed the technical program.