XtreemOS is a Linux-based operating system with native support for virtual organizations (VO’s), for building large-scale resource federations. XtreemOS has been designed as a grid operating system, supporting the model of resource sharing among independent administrative domains. We argue, however, that the VO concept can be used to establish either resource sharing or resource isolation, or e...

Ever since computer networks have become popular libraries tend to join into federations. Each federated digital library, apart from delivering discovery and navigation features within their own database allows users to search among other digital library systems. However the variety of users introduces various types of libraries and eventually types of federations of libraries. We present the c...

We present the design and implementation of a protocol for supporting Wireless LAN (WLAN) roaming federations. Unlike existing approaches, which incur significant management overhead, our protocol is designed specifically with reducing management complexity in mind. More specifically, the next generation operators that oversee our WLAN federations are not involved in WLAN provisioning decisions...

In this paper we present our authorization framework that supports the dynamic set-up of Web service federations for sharing data within virtual federations. Building on previous work, where we showed how the access control of Web services can be consolidated with the access control of the underlying database systems, we focus on the delegation of trust across administrative boundaries, thus en...

Providing integrated access to data distributed over Linked Data Federations has become a major research challenge, mainly due to heterogeneity problems. In such context, this work proposes a solution for query decomposition over Linked Data Federations, i.e., sets of RDF data sources published according to the principles of Linked Data. Our main contribution lies in the definition and implemen...