Security requirements approached at the enterprise level initiate the need for models that capture the organisational and distributed aspects of information usage. Such models have to express organisation-specific security policies and internal controls aiming to protect information against unauthorised access and modification, and against usage of information for unintended purposes. This diss...

In view of the legislations on privacy, we address the issue of limiting non-technical responsibility of the administrators of a computer network. A primary concern regards the anonymity of channels within a local network. Solutions proposed in the literature increase significantly the traffic. In this paper we argue that it is possible to implement anonymous and private channels in a local net...

We introduce signatures where signers can only sign messages that conform to some policy, yet privacy of the policy is maintained. We provide definitions and show that policy-based signatures provide a framework which yields a unified view of many other existing types of signatures that now appear as special cases. We also show how still other primitives are easily realized using policy-based s...

with rapid development and increase in the amount of available resources in E-learning platforms, the need to design new architecture for such systems has become inevitable to improve the search quality and simplifying ways to take online courses. The integration of multi-agent systems has played a very important role in developing open, interactive and distributed learning systems. A lot of re...

Conventional means of selecting a service are predominantly based on the results returned from service discovery. Typically most approaches employ a matchmaker which works in tandem with a service registry and user preferences based on the functionality of services. Nonfunctional attributes of services, such as reliability, timeliness and other quality of service criteria are typically not addr...

We describe a point-based policy iteration (PBPI) algorithm for infinite-horizon POMDPs. PBPI replaces the exact policy improvement step of Hansen’s policy iteration with point-based value iteration (PBVI). Despite being an approximate algorithm, PBPI is monotonic: At each iteration before convergence, PBPI produces a policy for which the values increase for at least one of a finite set of init...

Quite often attacks are enabled by mis-configurations generated by human errors. Policy-based network management has been proposed to cope with this problem: goals are expressed as high-level rules that are then translated into low-level configurations for network devices. While the concept is clear, there is a lack of tools supporting this strategy. We propose an ontology-based policy translat...