Dario Colazzo

Mohamed-Amine Baazizi, Nour El Houda Ben Ali, Dario Colazzo et al.

JSON Schema is the de facto standard for describing the structure of JSON documents. Reasoning about JSON Schema inclusion - whether every instance satisfying a schema S1 also satisfies a schema S2 -is a key building block for a variety of tasks, including version and API compatibility checks, schema refactoring tools, and large-scale schema corpus analysis. Existing approaches fall into two families: rule-based algorithms that are efficient but incomplete and witness generation-based algorithms that are complete but oftentimes extremely slow. This paper introduces a new approach that reconciles the efficiency of rule-based procedures with the completeness of the witness-generation technique, by enriching the latter with a specialized form of normalization. This refutational normalization paves the way for use-cases that are too hard for current tools. Our experiments with real-world and synthetic schemas show that the refutational normalization greatly advances the state-of-the-art in JSON Schema inclusion checking.

Zahra Vahidi Ferdousi, Dario Colazzo, Elsa Negre

Recommender systems help users to find their appropriate items among large volumes of information. Different types of recommender systems have been proposed. Among these, context-aware recommender systems aim at personalizing as much as possible the recommendations based on the context situation in which the user is. In this paper we present an approach integrating contextual information into the recommendation process by modeling either item-based or user-based influence of the context on ratings, using the Pearson Correlation Coefficient. The proposed solution aims at taking advantage of content and contextual information in the recommendation process. We evaluate and show effectiveness of our approach on three different contextual datasets and analyze the performances of the variants of our approach based on the characteristics of these datasets, especially the sparsity level of the input data and amount of available information.