David J. Carmichael Judy Kay Bob Kummerfeld Consistent Modelling of Users, Devices and Sensors in a Ubiquitous Computing Environment. 197-234 2005 15 User Model. User-Adapt. Interact. 3-4 http://dx.doi.org/10.1007/s11257-005-0001-z db/journals/umuai/umuai15.html#CarmichaelKK05