Yannis Georgalis Dimitris Grammenos Constantine Stephanidis Middleware for Ambient Intelligence Environments: Reviewing Requirements and Communication Technologies. 168-177 2009 HCI (6) http://dx.doi.org/10.1007/978-3-642-02710-9_20 conf/hci/2009-6 db/conf/hci/hci2009-6.html#GeorgalisGS09