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…
Nofar Carmeli, Technion, Israel Institute of Technology 28 February 2020, 10:30-11:30 ENS, S16 The Complexity of Answering Unions of Conjunctive Queries We discuss the complexity of enumerating (listing) the answers to a query over a relational database. In particular, we consider three variants: arbitrary order, uniformly random order, and random…
Evgenia (Eugenia) Ternovska Associate Professor | School of Computing Science Simon Fraser University 8888 University Dr., Burnaby, B.C. V5A 1S6 13 February 2020, 10:30-11:30 ENS, S16 Logic of Information Flows: Expressing Reachability and Cardinality Properties A challenge in descriptive complexity is to identify logics with low complexity that simultaneously express…
Silviu Maniu, Université Paris-Sud 7 February 2020, 10:30-11:30 ENS, S16 An Experimental Study of the Treewidth of Real-World Data Treewidth is a parameter that measures how tree-like a data instance is, and whether it can reasonably be decomposed into a data structure resembling a tree. Many computation tasks are known…
Juan Sequeda 29 November 2019, 10:30-11:30 ENS, S16 A Brief History of Knowledge Graph’s Main Ideas Knowledge Graphs can be considered to be fulfilling an early vision in Computer Science of creating intelligent systems that integrate knowledge and data at large scale. The term “Knowledge Graph” has rapidly gained popularity…
6 December 2019, 10:30-11:30 ENS, S16 Order-invariant first-order logic over hollow trees. Order-invariant first-order logic is the extension of first-order logic in which the usage of an additional ordering relation on the structure’s universe is allowed, provided that the evaluation of sentences is independent of the choice of a particular…
8 November 2019, 10:30-11:30 ENS, S16 Weighted Linear Bandits for Non-stationary environments. We consider a stochastic linear bandit model in which the available actions correspond to arbitrary context vectors whose associated rewards follow a non-stationary linear regression model. In this setting, the unknown regression parameter is allowed to vary in…
