Daniel Olmedilla

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We introduce the provisional trust negotiation framework PROTUNE, for combining distributed trust management policies with provisional-style business rules and access-control related actions. The framework features a powerful declarative metalanguage for driving some critical negotiation decisions, and integrity constraints for monitoring negotiations and(More)
Researchers have recently begun to develop and investigate policy languages to describe trust and security requirements on the Semantic Web [14, 24]. Such policies will be one component of a run-time system that can negotiate to establish trust on the Semantic Web. In this paper, we show how to express different kinds of access control policies and control(More)
Gaining access to sensitive resources on the Web usually involves an explicit registration step, where the client has to provide a predetermined set of information to the server. The registration process yields a login/password combination, a cookie, or something similar that can be used to access the sensitive resources. In this paper we show how an(More)
Privacy-preserving document exchange among collaboration groups in an enterprise as well as across enterprises requires techniques for sharing and search of access-controlled information through largely untrusted servers. In these settings search systems need to provide confidentiality guarantees for shared information while offering IR properties(More)
Semantic Web Services enable the dynamic discovery of services based on a formal, explicit specification of the requester needs. The actual Web Services that will be used to satisfy the requester’s goal are selected at run-time and, therefore, they are not known beforehand. As a consequence, determining whether the selected services can be trusted becomes(More)
In order to achieve interoperability among learning repositories, implementers require a common communication framework for querying. This paper proposes a set of methods referred to as Simple Query Interface (SQI) as a universal interoperability layer for educational networks. The methods proposed can be used by a source for configuring and submitting(More)
Semantic Web databases allow efficient storage and access to RDF statements. Applications are able to use expressive query languages in order to retrieve relevant metadata to perform different tasks. However, access to metadata may not be public to just any application or service. Instead, powerful and flexible mechanisms for protecting sets of RDF(More)
Modeling competences is an integral part of many Human Resource (HR) and e-Learning related activities. HR departments use competence descriptions to define requirements needed for performing specific tasks or jobs. The same competences are acquired by employees and applicants by e.g. experience or certifications. Typically, HR departments need to match(More)
The Semantic Web aims at enabling sophisticated and autonomic machine to machine interactions without human intervention, by providing machines not only with data but also with its meaning (semantics). In this setting, traditional security mechanisms are not suitable anymore. For example, identity-based access control assumes that parties are known in(More)