13th Reasoning Web Summer School (RW 2017)

The research areas of Semantic Web, Linked Data and Knowledge Graphs have received a lot of attention in academia and industry recently. Since its inception in 2001, the Semantic Web has aimed at enriching the existing Web with meta-data and processing methods, so as to provide Web-based systems with intelligent capabilities such as context-awareness and decision support. Over the years, the Semantic Web vision has been driving many community efforts which have invested a lot of resources in developing vocabularies and ontologies for annotating their resources semantically. Besides ontologies, rules have long been a central part of the Semantic Web framework and are available as one of its fundamental representation tools, with logic serving as a unifying foundation. Linked data is a related research area which studies how one can make RDF data available on the Web, and interconnect it with other data with the aim of increasing its value for everybody. Knowledge Graphs have been shown useful not only for Web search (as demonstrated by Google, Bing etc) but also in many application domains.

Many advanced capabilities required by Semantic Web, Linked Data and Knowledge Graph application scenarios call for reasoning. Thus, a perspective centered on the reasoning techniques complementing other research efforts in this area is desirable. The Reasoning Web series of annual Summer Schools is devoted to this perspective, and gives insight into the Semantic Web, Linked Data, Knowledge Graph, Ontologies, Rules, and Logic. It was started in 2005 on behalf of the work package “Education and Training (ET)” of the Network of Excellence REWERSE, and since then it has been established as a major annual event in the above mentioned research areas. It is primarily intended for postgraduate (Ph.D. or M.Sc.) students, postdoctoral researchers, young researchers, and senior researchers wishing to learn about Reasoning on the Semantic Web and related issues.The 13th Reasoning Web Summer School will take place in London, UK, hosted by Birkbeck, University of London, from July 7th to July 11th, 2017.


Lecture materials will be published in Lecture Notes in Computer Science (LNCS).


Tentative deadlines

ApplicationApril 30th, 2016
NotificationMay 15th, 2016
RegistrationMay 30th, 2016




Giovambattista Ianni, Università della Calabria

Domenico Lembo, Sapienza Università di Roma


Scientific Advisory Board

Leopoldo Bertossi, Carleton University

Wolfgang Faber, University of Huddersfield

Birte Glimm, Universität Ulm

Georg Gottlob, Oxford University

Steffen Staab, University of Koblenz-Landau



Challenges for Semantic Data Integration on the Web of Open Data
Axel Polleres, Sebastian Neumaier, Jürgen Umbrich

In this lecture we will discuss and introduce challenges of integrating openly available Web data and how to solve them. Firstly, while we will address this topic from the viewpoint of Semantic Web research, not all data is readily available as RDF or Linked Data, so we will give an introduction to different Data formats prevalent on the Web, namely, tabular, tree-shaped, and graph data. Secondly, not all open data is really completely open, so we will discuss and address issues around licences, terms of usage associated with Open data, and the documentation of data provenance. Thirdly, we will discuss issues associated with data quality in Open Data on the Web and how Semantic Web techniques and vocabularies can be used to describe and remedy them. Fourth, we will turn to issues around searchability and integration of Open Data (how to enable basic search, table search, finding related tables, up to building knowledge graphs) and discuss how/whether semantic search can help to overcome these. Lastly, we summarize further issues not covered in depth, such as multi-linguality, temporal aspects (archiving, evolution, temporal querying), as well as how/whether OWL and RDFS reasoning on top of integrated open data could be help.

Ontological query answering over semantic data
Giorgos Stamou

Modern information retrieval systems advance user experience on the basis of concept-based rather than keyword-based query answering. In particular, efficient user interfaces involve terminological descriptions of the domain of interest, expressed in formal knowledge representation formalisms. Ontological representation and reasoning based on description logics play an important role, providing expressive concept-level query languages with formal semantics and reasoning support. On the other hand, most real-life applications use huge amounts of data, consequently, efficient data storage and retrieval focuses on methodologies that take advantage of the physical storage using simple rather than sophisticated data models. Within this context, ontology-based query answering is one of the widely used approaches, especially for web applications, involving data from different sources, in different formats. Here, we present methods for data integration, query rewriting and query answering based on both tractable and expressive description logics. Specifically, we focus on semantic data representation based on relational schemas to ontology mappings, ontology-based query rewriting for tractable description logics and approximate query answering techniques for expressive description logics.

Integrating Relational Databases with the Semantic Web
Juan Sequeda

Answer Set Programming (ASP) has become an established paradigm for knowledge representation and reasoning, in particular, when it comes to solving knowledge-intense combinatorial (optimization) problems. ASP’s unique pairing of a simple yet rich modeling language with highly performant solving technology has led to an increasing interest in ASP in academia as well as industry. To further boost this development and make ASP fit for real world applications it is indispensable to equip it with means for an easy integration into complex software environments and of complementary forms of reasoning.

In this tutorial, we describe how both issues are addressed in the ASP system clingo. At first, we outline features of clingo’s application programming interface (API) that are essential for multi-shot ASP solving that allows for dealing with continuously changing logic programs. We then switch to the API’s design for integrating complementary forms of reasoning and detail this in an extensive case study dealing with the integration of difference logic. We show how the syntax of the respective constraints is added to the modeling language and seamlessly merged into grounding process. And then develop in detail two theory propagators for difference logic and present how they are integrated in to clingo’s solving process.

Reasoning on data-aware business processes
Marco Montali
Datalog revisited for reasoning in Linked Data
Marie-Christine Rousset



Challenges for Semantic Data Integration on the Web of Open Data
Axel Polleres, Vienna University of Economics and Business (WU Wien)

Alex Polleres joined the Institute of Information Business of Vienna University of Economics and Business (WU Wien) in Sept 2013 as a full professor in the area of “Data and Knowledge Engineering”. He obtained his Ph.D. and habilitation from Vienna University of Technology and worked at University of Innsbruck, Austria, Universidad Rey Juan Carlos, Madrid, Spain, the Digital Enterprise Research Institute (DERI) at the National University of Ireland, Galway, and for Siemens AG’s Corporate Technology Research division before joining WU Wien. His research focuses on querying and reasoning about ontologies, rules languages, logic programming, Semantic Web technologies, Web services, knowledge management, Linked Open Data, configuration technologies and their applications. He has worked in several European and national research projects in these areas. Axel has published more than 100 articles in journals, books, and conference and workshop contributions and co-organised several international conferences and workshops in the areas of logic programming, Semantic Web, data management, Web services and related topics and acts/acted as editorial board member for JWS, SWJ and IJSWIS. Moreover, he actively contributed to international standardisation efforts within the World Wide Web Consortium (W3C) where he co-chaired the W3C SPARQL working group.

Ontological query answering over semantic data
Giorgos Stamou, School of Electrical and Computer Engineering, National Technical University of Athens

Dr Giorgos Stamou is currently an Associate Professor in the School of Electrical and Computer Engineering, National Technical University of Athens. His research interests include ontological knowledge representation and reasoning, uncertainty handling and machine learning, and applications to semantic annotation, data access and data analytics. He has published more than 150 papers in scientific Journals and Conference Proceedings, co-edited a book and two conference proceedings, served as member of the organisation committees of several conferences (co-chair of DL Workshop 2015, local co-organiser of RR and RW 2014), participated in W3C and RuleML standardisation activities and has worked in more than 50 research projects.

Integrating Relational Databases with the Semantic Web
Juan Sequeda, Capsenta

Juan F. Sequeda is the co-founder of Capsenta, a spin-off from his research, and the Senior Director of Capsenta Labs. He holds a PhD in Computer Science from the University of Texas at Austin. His research interests are on the intersection of Logic and Data and in particular between the Semantic Web and Relational Databases for data integration, ontology based data access and semantic/graph data management. Juan is the recipient of the NSF Graduate Research Fellowship, received 2nd Place in the 2013 Semantic Web Challenge for his work on ConstituteProject.org, Best Student Research Paper at the 2014 International Semantic Web Conference and the 2015 Best Transfer and Innovation Project awarded by Institute for Applied Informatics. Juan is the PC chair of the ISWC 2017 In-Use track, is on the Editorial Board of the Journal of Web Semantics, member of multiple program committees (ISWC, ESWC, WWW, AAAI, IJCAI), organizer of the AMW Summer School and co-creator of the Consuming Linked Data Workshop series. Juan is a member of the Graph Query Languages task force of the Linked Data Benchmark Council (LDBC) and has also been an invited expert member and standards editor at the World Wide Web Consortium (W3C).

A Tutorial on Hybrid Answer Set Solving
Torsten Schaub, University of Potsdam, Germany and Inria, Bretagne Atlantique, Rennes

Torsten Schaub is university professor at the University of Potsdam, Germany, and holds an international chair at Inria Rennes, France. He is a fellow of ECCAI and the current president of the Association of Logic Programming. His current research focus lies on Answer set programming (ASP) and its applications, which materializes at potassco.org, the home of the open source project Potassco bundling software for ASP developed at Potsdam.

Reasoning on data-aware business
Marco Montali, Free University of Bozen-Bolzano – TBA Axel Polleres, Vienna University of Economics and Business (WU Wien)
Datalog revisited for reasoning in Linked Data
Marie-Christine Rousset, University Grenoble-Alpes