Search Results for author: Ian Horrocks

Found 29 papers, 7 papers with code

On Event-Driven Knowledge Graph Completion in Digital Factories

no code implementations8 Sep 2021 Martin Ringsquandl, Evgeny Kharlamov, Daria Stepanova, Steffen Lamparter, Raffaello Lepratti, Ian Horrocks, Peer Kröger

Smooth operation of such factories requires that the machines and engineering personnel that conduct their monitoring and diagnostics share a detailed common industrial knowledge about the factory, e. g., in the form of knowledge graphs.

Knowledge Graph Completion

Computing CQ lower-bounds over OWL 2 through approximation to RSA

no code implementations1 Jul 2021 Federico Igne, Stefano Germano, Ian Horrocks

We present a novel approximation of OWL 2 ontologies into RSA, and an algorithm to compute a closer (than PAGOdA) lower bound approximation using the RSA combined approach.

Knowledge-aware Zero-Shot Learning: Survey and Perspective

1 code implementation26 Feb 2021 Jiaoyan Chen, Yuxia Geng, Zhuo Chen, Ian Horrocks, Jeff Z. Pan, Huajun Chen

Zero-shot learning (ZSL) which aims at predicting classes that have never appeared during the training using external knowledge (a. k. a.

Zero-Shot Learning

OWL2Vec*: Embedding of OWL Ontologies

1 code implementation30 Sep 2020 Jiaoyan Chen, Pan Hu, Ernesto Jimenez-Ruiz, Ole Magnus Holter, Denvar Antonyrajah, Ian Horrocks

Semantic embedding of knowledge graphs has been widely studied and used for prediction and statistical analysis tasks across various domains such as Natural Language Processing and the Semantic Web.

Knowledge Graphs Language Modelling

Correcting Knowledge Base Assertions

1 code implementation19 Jan 2020 Jiaoyan Chen, Xi Chen, Ian Horrocks, Ernesto Jimenez-Ruiz, Erik B. Myklebus

The usefulness and usability of knowledge bases (KBs) is often limited by quality issues.

Datalog Reasoning over Compressed RDF Knowledge Bases

no code implementations27 Aug 2019 Pan Hu, Jacopo Urbani, Boris Motik, Ian Horrocks

Materialisation is often used in RDF systems as a preprocessing step to derive all facts implied by given RDF triples and rules.

Canonicalizing Knowledge Base Literals

2 code implementations26 Jun 2019 Jiaoyan Chen, Ernesto Jimenez-Ruiz, Ian Horrocks

Ontology-based knowledge bases (KBs) like DBpedia are very valuable resources, but their usefulness and usability is limited by various quality issues.

Learning Semantic Annotations for Tabular Data

1 code implementation30 May 2019 Jiaoyan Chen, Ernesto Jimenez-Ruiz, Ian Horrocks, Charles Sutton

The usefulness of tabular data such as web tables critically depends on understanding their semantics.

Type prediction

Modular Materialisation of Datalog Programs

no code implementations6 Nov 2018 Pan Hu, Boris Motik, Ian Horrocks

The semina\"ive algorithm can materialise all consequences of arbitrary datalog rules, and it also forms the basis for incremental algorithms that update a materialisation as the input facts change.

ColNet: Embedding the Semantics of Web Tables for Column Type Prediction

1 code implementation4 Nov 2018 Jiaoyan Chen, Ernesto Jimenez-Ruiz, Ian Horrocks, Charles Sutton

Automatically annotating column types with knowledge base (KB) concepts is a critical task to gain a basic understanding of web tables.

Type prediction

The Window Validity Problem in Rule-Based Stream Reasoning

no code implementations7 Aug 2018 Alessandro Ronca, Mark Kaminski, Bernardo Cuenca Grau, Ian Horrocks

Rule-based temporal query languages provide the expressive power and flexibility required to capture in a natural way complex analysis tasks over streaming data.

Knowledge-based Transfer Learning Explanation

1 code implementation22 Jul 2018 Jiaoyan Chen, Freddy Lecue, Jeff Z. Pan, Ian Horrocks, Huajun Chen

Machine learning explanation can significantly boost machine learning's application in decision making, but the usability of current methods is limited in human-centric explanation, especially for transfer learning, an important machine learning branch that aims at utilizing knowledge from one learning domain (i. e., a pair of dataset and prediction task) to enhance prediction model training in another learning domain.

Decision Making Transfer Learning

Consequence-based Reasoning for Description Logics with Disjunction, Inverse Roles, Number Restrictions, and Nominals

no code implementations3 May 2018 David Tena Cucala, Bernardo Cuenca Grau, Ian Horrocks

We present a consequence-based calculus for concept subsumption and classification in the description logic ALCHOIQ, which extends ALC with role hierarchies, inverse roles, number restrictions, and nominals.

General Classification

Stratified Negation in Limit Datalog Programs

no code implementations25 Apr 2018 Mark Kaminski, Bernardo Cuenca Grau, Egor V. Kostylev, Boris Motik, Ian Horrocks

There has recently been an increasing interest in declarative data analysis, where analytic tasks are specified using a logical language, and their implementation and optimisation are delegated to a general-purpose query engine.

Optimised Maintenance of Datalog Materialisations

no code implementations10 Nov 2017 Pan Hu, Boris Motik, Ian Horrocks

The Delete/Rederive (DRed) and the Backward/Forward (B/F) algorithms solve this problem for general datalog, but both contain steps that evaluate rules 'backwards' by matching their heads to a fact and evaluating the partially instantiated rule bodies as queries.

Stream Reasoning in Temporal Datalog

no code implementations10 Nov 2017 Alessandro Ronca, Mark Kaminski, Bernardo Cuenca Grau, Boris Motik, Ian Horrocks

In recent years, there has been an increasing interest in extending traditional stream processing engines with logical, rule-based, reasoning capabilities.

Foundations of Declarative Data Analysis Using Limit Datalog Programs

no code implementations19 May 2017 Mark Kaminski, Bernardo Cuenca Grau, Egor V. Kostylev, Boris Motik, Ian Horrocks

Motivated by applications in declarative data analysis, we study $\mathit{Datalog}_{\mathbb{Z}}$---an extension of positive Datalog with arithmetic functions over integers.

The Bag Semantics of Ontology-Based Data Access

no code implementations19 May 2017 Charalampos Nikolaou, Egor V. Kostylev, George Konstantinidis, Mark Kaminski, Bernardo Cuenca Grau, Ian Horrocks

The ontology is linked to the sources using mappings, which assign views over the data to ontology predicates.

Towards Analytics Aware Ontology Based Access to Static and Streaming Data (Extended Version)

no code implementations18 Jul 2016 Evgeny Kharlamov, Yannis Kotidis, Theofilos Mailis, Christian Neuenstadt, Charalampos Nikolaou, Özgür Özcep, Christoforos Svingos, Dmitriy Zheleznyakov, Sebastian Brandt, Ian Horrocks, Yannis Ioannidis, Steffen Lamparter, Ralf Möller

Real-time analytics that requires integration and aggregation of heterogeneous and distributed streaming and static data is a typical task in many industrial scenarios such as diagnostics of turbines in Siemens.

Extending Consequence-Based Reasoning to SRIQ

no code implementations14 Feb 2016 Andrew Bate, Boris Motik, Bernardo Cuenca Grau, František Simančík, Ian Horrocks

Consequence-based calculi are a family of reasoning algorithms for description logics (DLs), and they combine hypertableau and resolution in a way that often achieves excellent performance in practice.

Ontology Module Extraction via Datalog Reasoning

no code implementations19 Nov 2014 Ana Armas Romero, Mark Kaminski, Bernardo Cuenca Grau, Ian Horrocks

Module extraction - the task of computing a (preferably small) fragment M of an ontology T that preserves entailments over a signature S - has found many applications in recent years.

Handling owl:sameAs via Rewriting

no code implementations13 Nov 2014 Boris Motik, Yavor Nenov, Robert Piro, Ian Horrocks

Rewriting is widely used to optimise owl:sameAs reasoning in materialisation based OWL 2 RL systems.

Acyclicity Notions for Existential Rules and Their Application to Query Answering in Ontologies

no code implementations4 Feb 2014 Bernardo Cuenca Grau, Ian Horrocks, Markus Krötzsch, Clemens Kupke, Despoina Magka, Boris Motik, Zhe Wang

Existential rules are closely related to the Horn fragments of the OWL 2 ontology language; furthermore, several prominent OWL 2 reasoners implement CQ answering by using the chase to materialise all relevant facts.

Completeness Guarantees for Incomplete Ontology Reasoners: Theory and Practice

no code implementations18 Jan 2014 Bernardo Cuenca Grau, Boris Motik, Giorgos Stoilos, Ian Horrocks

Since ontologies and typical queries are often fixed at application design time, our approach allows application developers to check whether a reasoner known to be incomplete in general is actually complete for the kinds of input relevant for the application.

Hypertableau Reasoning for Description Logics

no code implementations15 Jan 2014 Boris Motik, Rob Shearer, Ian Horrocks

We present a novel reasoning calculus for the description logic SHOIQ^+---a knowledge representation formalism with applications in areas such as the Semantic Web.

Computing Datalog Rewritings beyond Horn Ontologies

no code implementations4 Apr 2013 Bernardo Cuenca Grau, Boris Motik, Giorgos Stoilos, Ian Horrocks

Rewriting-based approaches for answering queries over an OWL 2 DL ontology have so far been developed mainly for Horn fragments of OWL 2 DL.

Introducing Nominals to the Combined Query Answering Approaches for EL

no code implementations29 Mar 2013 Giorgio Stefanoni, Boris Motik, Ian Horrocks

So-called combined approaches answer a conjunctive query over a description logic ontology in three steps: first, they materialise certain consequences of the ontology and the data; second, they evaluate the query over the data; and third, they filter the result of the second phase to eliminate unsound answers.

A Description Logic Primer

no code implementations19 Jan 2012 Markus Krötzsch, Frantisek Simancik, Ian Horrocks

This paper provides a self-contained first introduction to description logics (DLs).

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