The Vadalog System: Datalog-based Reasoning for Knowledge Graphs

Over the past years, there has been a resurgence of Datalog-based systems in the database community as well as in industry. In this context, it has been recognized that to handle the complex knowl\-edge-based scenarios encountered today, such as reasoning over large knowledge graphs, Datalog has to be extended with features such as existential quantification. Yet, Datalog-based reasoning in the presence of existential quantification is in general undecidable. Many efforts have been made to define decidable fragments. Warded Datalog+/- is a very promising one, as it captures PTIME complexity while allowing ontological reasoning. Yet so far, no implementation of Warded Datalog+/- was available. In this paper we present the Vadalog system, a Datalog-based system for performing complex logic reasoning tasks, such as those required in advanced knowledge graphs. The Vadalog system is Oxford's contribution to the VADA research programme, a joint effort of the universities of Oxford, Manchester and Edinburgh and around 20 industrial partners. As the main contribution of this paper, we illustrate the first implementation of Warded Datalog+/-, a high-performance Datalog+/- system utilizing an aggressive termination control strategy. We also provide a comprehensive experimental evaluation.Comment: Extended version of VLDB paper <https://doi.org/10.14778/3213880.3213888

Expressing Biological Problems with Logical Reasoning Languages

Biology represents a very challenging domain that is typically tackled by experts in the field, with few or no interactions with the Web knowledge and rules interoperation community. However, there has been a considerable growth of data regarding biological aspects in the last decades. Moreover, the COVID-19 pandemic has traced an unprecedented point in history, where tons of information have been collected in laboratories worldwide and deposited into open data banks. Inspired by the current needs and backed by a solid knowledge base (our extensional knowledge source) called CoV2K, we propose to express and resolve a series of problems related to the SARS-CoV-2 virus and its interpretation. We formulate our queries as rules in Vadalog (our knowledge representation and reasoning language) and input them to its related logic-based reasoning system. Four cases are presented that allow to explore 1) variants effects and how they are explained in scientific literature; 2) the most typical mutations of a variant; 3) the most likely acquisition of a new mutation by a given variant and the associated reported effects; 4) the most relevant mutations of the virus according to the community. Expressing biological problems using a logic formalism is a major challenge, due to the intrinsic complexity of the domain. The four use cases show that a logical formalism is effective in expressing relevant problems for understanding the current evolution of SARS-CoV-2 variants, an essential aspect of the COVID-19 pandemic

Swift Logic for Big Data and Knowledge Graphs

Many modern companies wish to maintain knowledge in the form of a corporate knowledge graph and to use and manage this knowledge via a knowledge graph management system (KGMS). We formulate various requirements for a fully-fledged KGMS. In particular, such a system must be capable of performing complex reasoning tasks but, at the same time, achieve efficient and scalable reasoning over Big Data with an acceptable computational complexity. Moreover, a KGMS needs interfaces to corporate databases, the web, and machinelearning and analytics packages. We present KRR formalisms and a system achieving these goals

Preface of the 31st Italian Symposium on Advanced Database Systems

This volume contains the proceedings of the 31st Italian Symposium on Advanced Database Systems (SEBD - Sistemi Evoluti per Basi di Dati), held in Galzinagno Terme (Padua, Italy) from 2 to 5 July 2023.</p

Preface of the 31st Italian Symposium on Advanced Database Systems

This volume contains the proceedings of the 31st Italian Symposium on Advanced Database Systems (SEBD - Sistemi Evoluti per Basi di Dati), held in Galzinagno Terme (Padua, Italy) from 2 to 5 July 2023.</p