or physically invisible to the users. They will alsobe deployedin a muchhigher quantity andpenetrate many moreapplicationareasthan traditional notionsof computer systems. This requirescomputersystemstobeadaptablewithinamuchwiderrangeofpossible tasks, subjected to much harsher conditions. To provide such features and functionality, computer devices will become tinieryetstillincreaseinsystemcomplexity;theymustconsumelesspower,while still supporting advanced computation and communications, such that they are highlyconnectedyetstilloperateasautonomousunits. Pervasiveandubiquitous computing researchaddressessuchissues by developingconcepts and technology for interweaving computers into our everyday life. The principal approach is to enhance system functionality and adaptability by recognizing context and situations in the environment.