    @inproceedings {Agudo2007a,
	title = {Attribute delegation in ubiquitous environments},
	booktitle = {3rd international conference on Mobile multimedia communications (MobiMedia {\textquoteright}07)},
	year = {2007},
	pages = {43:1{\textendash}43:6},
	publisher = {ICST},
	organization = {ICST},
	address = {Nafpaktos, Greece},
	abstract = {<p>When delegation is implemented using the attribute certificates in a Privilege Management Infrastructure (PMI), this one reaches a considerable level of distributed functionality. However, the approach is not flexible enough for the requirements of ubiquitous environments. Additionally, the PMI can become a too complex solution for devices such as smartphones and PDAs, where resources are limited. In this work, we solve the previous limitations by defining a second class of attributes, called domain attributes, which are managed directly by users and are not right under the scope of the PMI, thus providing a light solution for constrained devices. The two classes of attributes are related by defining a simple ontology. We also introduce in the paper the concept of Attribute Federation which is responsible for supporting domain attributes and the corresponding ontology.</p>},
	isbn = {978-963-06-2670-5},
	author = {Isaac Agudo and Javier Lopez and Jose A. Montenegro}
}
