Domenico Rosaci

Learn More
Histograms are used to summarize the contents of relations for the estimation of query result sizes into a number of buckets. Several techniques (e.g., MaxDiff and VOptimal) have been proposed in the past for determining bucket boundaries which provide better estimations. This paper proposes to use a 32-bit information (4-level tree index) for each bucket(More)
In the last years, the Web community has shown a broad interest in Web services that handle multimedia contents. To improve the usability of these services different tools have been proposed in the literature, and in this context agent-based recommender systems appear to be a promising solution. However, the recommender systems presented in the past do not(More)
Several models have been proposed in the past for representing both reliability and reputation. However, we remark that a crucial point in the practical use of these two measures is represented by the possibility of suitably combining them to support the agent’s decision. In the past, we proposed a reliability-reputation model, called RRAF, that allows the(More)
In Multi-Agent Systems the main goal is providing fruitful cooperation among agents in order to enrich the support given to user activities. Cooperation can be implemented in many ways, depending on how local knowledge of agents is represented and consists, in general, in providing the user with an integrated view of individual knowledge bases. But the main(More)
The role of trust measures is particularly relevant in competitive multi-agent systems. Recent studies highlight the importance of correctly balancing direct measures, as the reliability, and indirect measures, as the reputation. The key problem is that an agent may have an insufficient direct knowledge of another agent, showing the necessity of using a(More)
A user that navigates on the Web using different devices should be characterized by a global profile, which represents his behaviour when using all these devices. Then, the user’s profile could be usefully exploited when interacting with a site agent that is able to provide useful recommendations on the basis of the user’s interests, on one hand, and to(More)
Social internetworking systems are a significantly emerging new reality; they group together a set of social networks and allow their users to share resources, to acquire opinions and, more in general, to interact, even if these users belong to different social networks and, therefore, did not previously know each other. In this context the notions of trust(More)
Peer-to-Peer (P2P) e-Learning systems have been designed to support people, providing them with the advantages brought by the Internet technology.They can be be effectively used to implement cooperative e-Learning systems, where the available knowledge for a student is not only from teachers, but also from other students having similar interests and(More)
Histograms are used to summarize the contents of relations into a number of buckets for the estimation of query result sizes. Several techniques have been proposed in the past for determining bucket boundaries which provide accurate estimations. However, while search strategies for optimal bucket boundaries are rather sophisticated, no much attention has(More)