3 June 2022, 10:30-11:30. ENS, Hauts du DI. Querying inconsistent prioritized data with ORBITS: Algorithms, implementation, and experiments We investigate practical algorithms for inconsistency-tolerant query answering over prioritized knowledge bases, which consist of a logical theory, a set of facts, and a priority relation between conflicting facts. We consider three…
20 May 2022, 10:30-11:30. ENS S16. Algorithm for consistent query answering under primary key constraints Databases often have constraints. One of the basic constraints is the “primary key constraint” which states there can be at most one tuple for every primary key. However, these days it is common to have…
12 April 2022, 10:30-11:30. ENS, S16 The Semiring-Based Provenance Framework for Graph Databases The growing amount of data collected by sensors or generated by human interaction has led to an increasing use of graph databases, an efficient model for representing intricate data. Techniques to keep track of the history of…
8 April 2022, 10:30-11:30. ENS, S16 Capturing Homomorphism-Closed Decidable Queries with Existential Rules Existential rules are a well studied ontology-mediated query language for which the chase represents a generic computational approach for query answering. It is straightforward that existential rule queries exhibiting chase termination are decidable and can only recognize…
Debabrota Basu, Inria Lille. 11 March 2022, 10:30-11:30. ENS S16. Verifying and Explaining Unfairness of Machine Learning Algorithms In recent years, machine learning (ML) algorithms have been deployed in safety-critical and high-stake decision-making, where the fairness or unbiasedness of algorithms bears significant importance. Fairness in ML centres on detecting bias…
Mikaël Monet, Inria Lille. 25 February 2022, 10:30-11:30. ENS, S16. Shapley Values for Relational Databases and Machine Learning The Shapley value is a game-theoretic function that can be used to distribute the wealth of a team in a cooperative game. This function has strong theoretical justifications has been applied across…
12 March 2021, 10:30-11:30 Online seminar: https://bbb.di.ens.fr/b/cam-pz6-kdj Traversal algorithms and heuristics for reasoning over logic based knowledge graphs (Davide Benedetto) Knowledge Graphs (KGs) provide a concise and intuitive abstraction for a variety of domains where edges capture the (potentially recursive) relationships between the entities. This is leading to the rise…
5 March 2021, 10:30-11:30 Online seminar: https://bbb.di.ens.fr/b/cam-pz6-kdj Grammars for Document Spanners (Liat Peterfreund) We propose a new grammar-based language for defining information-extractors from documents (text) that is built upon the well-studied framework of Document Spanners for extracting structured data from text. While previously studied formalisms for document spanners are mainly…
Meghyn Bienvenu, CNRS, University of Bordeaux 18 December 2020, 10:30-11:30 Online seminar: https://bbb.di.ens.fr/b/cam-pz6-kdj Preferred repairs over inconsistent knowledge bases and connections to argumentation A fundamental notion when reasoning over inconsistent knowledge bases is that of a repair, defined as a maximal subset of the data that is consistent w.r.t. the…
Val Tannen, University of Pennsylvania 21 February 2020, 10:00-11:00 ENS, S16 Provenance Analysis for First-order Model Checking Is a given finite structure a model of a given first-order sentence? The provenance analysis of this question determines how its answer depends on the atomic facts that determine the structure. Provenance questions…
