Keynote speakers

Invited Keynote Speakers

Ian Horrocks

University of Oxford, UK

Title: 

Abstract:

Logic based "Semantic Technologies" are maturing rapidly, with RDF and OWL now being deployed in diverse application domains, and with major technology vendors starting to augment their existing systems accordingly. For example, the Optique project has successfully piloted Ontology Based Data Access in the energy domain, and Oracle Inc. has enhanced its well-known database management system with modules that use RDF/OWL ontologies to support "semantic data management". Such applications increasingly focus on data, and critically depend on efficient query answering services; this in turn depends on the provision of robustly scalable reasoning systems. In this talk I will review the evolution of Semantic Technologies to date, and show how research ideas from logic based knowledge representation developed into a mainstream technology. I will then go on to examine the scalability challenges arising from deployment in large scale applications, particularly those that primarily focus on query answering over large datasets, compare various different approaches and present some results from ongoing research in the area.

Short Bio:

Ian Horrocks is a full professor in the Oxford University Department of Computer Science and a visiting professor in the Department of Informatics at the University of Oslo. His research interests include logic-based knowledge representation and reasoning and semantic technologies, with a particular focus on ontology languages and applications. He was an author of the OIL, DAML+OIL, and OWL ontology language standards, chaired the W3C working group that standardised OWL 2, and developed many of the algorithms, optimisation techniques and reasoning systems that underpin OWL applications. He has participated in numerous national and international research projects, and is currently Scientific Director of the EU funded Optique project, which is deploying semantic technologies in the Oil & Gas and Power Generation industries. He is a Fellow of the Royal Society, a member of Academia Europaea, an ECCAI Fellow and a Fellow of the British Computer Society.

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Leonid Libkin

University of Edinburgh, UK

Title:  Efficient Computation of Certain Answers: Breaking the CQ Barrier

Abstract:

Computing certain answers is the standard way of answering queries over incomplete data; it is also used in many applications such as data integration, data exchange, consistent query answering, ontology-based data access, etc. Unfortunately certain answers are often computationally expensive, and in most applications their complexity is intolerable if one goes beyond the class of conjunctive queries (CQs), or a slight extension thereof.

However, high computational complexity does not yet mean one cannot approximate certain answers efficiently. In this talk we survey several recent results on finding such efficient and correct approximations, going significantly beyond CQs. We do so in a setting of databases with missing values, and first-order (relational calculus/algebra) queries. Even the class of queries where the standard database evaluation produces correct answers is larger than previously thought. When it comes to approximations, we present two schemes with good theoretical complexity. One of them also performs very well in practice, and restores correctness of SQL query evaluation on databases with nulls.

Short Bio:

Leonid Libkin is Professor of Foundations of Data Management in the School of Informatics at the University of Edinburgh. He was previously a Professor at the University of Toronto and a member of research staff at Bell Laboratories in Murray Hill. He received his PhD from the University of Pennsylvania in 1994.  His main research interests are in the areas of data management and applications of logic in computer science. He has written five books and over 200 technical papers. His awards include a Marie Curie Chair Award and five Best Paper Awards. He has chaired programme committees of major database conferences (ACM PODS, ICDT) and was the conference chair of the 2010 Federated Logic Conference. He is a fellow of the ACM, a fellow of the Royal Society of Edinburgh, and a member of Academia Europaea.

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Meghyn Bienvenu

CNRS & University of Montpellier, France

Title: On the Limits and Possibilities of Query Rewriting

Abstract: 

Recent years have seen an increasing interest in ontology-mediated query answering (OMQA), in which the semantic knowledge provided by an ontology is exploited when querying data. Adding an ontology has several advantages (e.g. simplifying query formulation, integrating data from different sources, providing more complete answers to queries), but it also makes the query answering task more difficult. Query rewriting, which reduces OMQA to the evaluation of database queries, allows OMQA to be implemented on top of existing database systems, thereby benefitting from the maturity and performance of such systems.

In this talk, I will give an overview of two recent lines of work aimed at understanding the limits and possibilities of query rewriting in OMQA. The first line of work arose out of the observation that while first-order rewritings always exist for ontologies formulated in DL-Lite, the rewritings generated by implemented rewriting engines were often prohibitively large. This motivated the study of the following succinctness problem:  under what circumstances can polynomial-size rewritings be achieved? If we move to richer ontology languages, it is no longer guaranteed that all ontology-query pairs possess a first-order rewriting, but it may nonetheless be the case that rewritings exist for many of the ontologies and queries encountered in practice. Thus, the second topic that I will discuss is how to devise methods for identifying those ontology-query pairs which admit rewritings.

Short Bio:

Meghyn Bienvenu is a full-time researcher at CNRS (Centre National de la Recherche Scientifique) and is affiliated with the LIRMM lab at the University of Montpellier. She obtained her PhD in 2009 from the University of Toulouse and was awarded the AFIA Prize for best French dissertation in artificial intelligence. Prior to joining the CNRS, she held a postdoctoral position at the University of Bremen. Her main topic of interest is knowledge representation and reasoning (KR), with a focus on description logic (DL) ontologies and their use in querying data. She is an active member of the DL and KR research communities and regularly serves on the program committees of major international conferences (like IJCAI, AAAI, KR, PODS). In recognition of her research achievements, she was awarded the 2016 CNRS Bronze Medal in the field of computer science, and she has been invited to give an Early Career Spotlight talk at this year's IJCAI conference. 

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 Abraham Bernstein

University of Zurich, Switzerland

Title: Society Rules

Abstract:

Our society is full of rules: rules authorize us to achieve our goals by endowing us with legitimation, they provide the necessary structure to understand the chaos of conflicting indications or tell-tales of a situation, and oftentimes they legitimate our actions. But rules in society are different than logical rules suggest to be: they are not as unshakeable, continuously renegotiated, often even accepted to be wrong but still used, and used as inspiration in the situated context rather than universal truth. Based on theories about the role of technology in society, this talk will first try to convey the role of rules in social science theory. Extending these insights, it will draw on examples to illustrate how they might be transferred to computer science or artificial intelligence to derive systems that are attuned to the role of rules in social environments and adhere to social rules in the environment in which they are used.

Short Bio:

Abraham Bernstein is a Full Professor of Informatics and Chair of the Department of Informatics at the University of Zurich (UZH), Switzerland. Before joining UZH, Abraham Bernstein was an Assistant Professor of Information Systems at NYU and gained practical experience in the financial industry. Basing his research on both social science (organizational psychology/sociology) and technical foundations (computer science, artificial intelligence) he is interested in combining both technical and social science insights to coordinate and cultivate dynamic human-machine systems. Recently, he has conducted research in diverse topics such as the Semantic Web, Human-Computer Interaction, CSCW, Crowdsourcing, or graph-oriented middleware and middle-ware.

Abraham Bernstein has repeatedly been on the program committee International Semantic Web Conference (ISWC), the World Wide Web Conference (WWW), and the IEEE International Conference on Data Mining (ICDM) as well as various workshops on the Semantic Web and machine learning. He was program chair (2009) and general chair (2012) of ISWC and is a member of the editorial board of the ACM Transactions on Intelligent Interactive Systems, the ACM Transactions on Internet Technology, and the Informatik Spektrum by Springer. Also, he is the co-Editor in Chief of the Journal of Web Semantics.