LaBRI Mini-Workshop on Reasoning on Data - Monday December 9th 2019 - 9h Salle 178 LaBRI Bât A30

On Monday December 9th, at the occasion of her HDR defense in the afternoon, Meghyn Bienvenu is organizing à mini-workshop on the theme of "reasoning on data" with talks from her three thesis reviewers.

Here is the schedule (abstracts can be found below): 
9:00 - 9:45 Foundations of query answering on inconsistent databases, Jef Wijsen (Univ. Mons, Belgium)

10:00-10:45 Direct and reverse rewritings in data interoperability, Maurizio Lenzerini (Univ. Roma La Sapienza, Italy)

11:00-11:45 Modularity and automated reasoning in description logics, Ulrike Sattler (Univ. Manchester, UK) 

The event will take place in room 178 at LaBRI. A bit of time between the talks is purposely left to allow for discussion with the speakers. 
These talks are open to all and represent a great opportunity to hear from these eminent researchers. The three talks are independent, so feel free to attend any combination.

Contact: Meghyn Bienvenu

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SPEAKER: Jef Wijsen 
TITLE: Foundations of query answering on inconsistent databases

ABSTRACT:
Notwithstanding the traditional view that database instances must respect all integrity constraints imposed on them,it is relevant to develop theories about how to handle database instances that violate some integrity constraints, and more particularly, how to cope with query answering in the presence of inconsistency. Such a theory developed over the past twenty years is currently known as “consistent query answering” (CQA). The aim of this talk is to summarize and discuss some core concepts and theoretical developments in CQA.

SPEAKER: Maurizio Lenzerini
TITLE: Direct and reverse rewritings in data interoperability

ABSTRACT:
Data interoperability refers to the issue of accessing and processing data from multiple sources in order to create more holisticand contextual information for improving data analysis and decision-making. A fundamental component of all data interoperabilityframeworks is the mapping. Indeed, put in an abstract way, any interoperability scenario is characterized by an architecture constituted of various autonomous nodes which hold information, and which are linked to other nodes by means of mappings. A mapping is a statement specifying that some relationship exists between pieces of information held by one node and pieces of information held by another node. It turns out that there are two fundamental ways, called direct and reverse query rewriting,respectively, to make use of mappings when performing query-oriented data interoperability tasks. The goal of this talk is to provide an account of both direct and reverse rewritings, focusing in particular on Ontology-based Data Management, which is a data interoperability scenario aiming at exploiting Knowledge Representation and Reasoning techniques for Data Management.

SPEAKER: Ulrike Sattler
TITLE: Modularity and automated reasoning in description logics

ABSTRACT: 
Description Logics (DLs) are decidable fragments of first order logics closely related to modal logics and the guarded fragment. Through their use as logical underpinning of the Semantic Web Ontology language OWL, they are now widely used in a range of areas. As a further consequence, DL reasoners have to deal with logical theories—called ontologies—of increasing size and complexity, and domain experts using DLs ask for increasingly sophisticated tool support. One of the many areas that have been considered in this aspect is modularity, a concept that has successfully been used to tame complexity and enable separation of concerns in other areas, in particular Software Engineering.In this talk, I will try to give a general overview of modularity in description logics and its various applications in automated reasoning. 

Firstly, we consider the task of extracting, from one ontology, a small/suitable fragment that captures a given topic, usually describedin terms of its signature. The question of suitability versus size here is interesting, and has given rise to different notions of modulesand their properties and algorithms for their extraction. Secondly, it would be extremely useful if we could “modularise” a large ontology into suitable coherent fragments (OWL has an “imports” construct that supports some kind of modular working with/storage of an ontology)]. Thirdly, reasoning over ontologies is often a highly complex task, and a natural question arising is whether/which form of modularity can be used and how to optimise reasoning.