ALBERT

Description: This paper describes the Ontologies of Linguistic Annotation (OLiA) as one of the data sets currently available as part of Linguistic Linked Open Data (LLOD) cloud. Within the LLOD cloud, the OLiA ontologies serve as a reference hub for annotation terminology for linguistic phenomena on a great band-width of languages, they have been used to facilitate interoperability and information integration of linguistic annotations in corpora, NLP pipelines, and lexical-semantic resources and mediate their linking with multiple community-maintained terminology repositories. Content Type Journal Article Pages - DOI 10.3233/SW-140167 Authors Christian Chiarcos, Applied Computational Linguistics (ACoLi), Department of Computer Science and Mathematics, Goethe-University Frankfurt am Main, Germany, http://acoli.cs.uni-frankfurt.de Maria Sukhareva, Applied Computational Linguistics (ACoLi), Department of Computer Science and Mathematics, Goethe-University Frankfurt am Main, Germany, http://acoli.cs.uni-frankfurt.de Journal Semantic Web Online ISSN 2210-4968 Print ISSN 1570-0844

Description: This paper describes the publication and linking of (parts of) PAROLE SIMPLE CLIPS (PSC), a large scale Italian lexicon, to the Semantic Web and the Linked Data cloud using the lemon model. The main challenge of the conversion is discussed, namely the reconciliation between the PSC semantic structure which contains richly encoded semantic information, following the qualia structure of the Generative Lexicon theory and the lemon view of lexical sense as a reified pairing of a lexical item and a concept in an ontology. The result is two datasets: one consists of a list of lemon lexical entries with their lexical properties, relations and senses; the other consists of a list of OWL individuals representing the referents for the lexical senses. These OWL individuals are linked to each other by a set of semantic relations and mapped onto the SIMPLE OWL ontology of higher level semantic types. Content Type Journal Article Pages - DOI 10.3233/SW-140168 Authors Riccardo Del Gratta, Istituto Di Linguistica Computazionale ‘A. Zampolli’, Consiglio Nazionale delle Ricerche, Via Moruzzi 1, Pisa, Italy. E-mail: first.last@ilc.cnr.it Francesca Frontini, Istituto Di Linguistica Computazionale ‘A. Zampolli’, Consiglio Nazionale delle Ricerche, Via Moruzzi 1, Pisa, Italy. E-mail: first.last@ilc.cnr.it Fahad Khan, Istituto Di Linguistica Computazionale ‘A. Zampolli’, Consiglio Nazionale delle Ricerche, Via Moruzzi 1, Pisa, Italy. E-mail: first.last@ilc.cnr.it Monica Monachini, Istituto Di Linguistica Computazionale ‘A. Zampolli’, Consiglio Nazionale delle Ricerche, Via Moruzzi 1, Pisa, Italy. E-mail: first.last@ilc.cnr.it Journal Semantic Web Online ISSN 2210-4968 Print ISSN 1570-0844

Description: The proliferation of contextualized knowledge in the Semantic Web (SW) has led to the popularity of knowledge formats such as quads in the SW community. A quad is an extension of RDF triple with the contextual information of the triple. We in this paper, study the problem of query answering over quads augmented with forall-existential bridge rules that enable interoperability of reasoning between the triples in various contexts. We call a set of quads together with such expressive bridge rules, a quad-system. Query answering over quad-systems is undecidable, in general. We derive decidable classes of quad-systems, for which query answering can be done using forward chaining. Sound, complete and terminating procedures, which are adaptations of the well known chase algorithm, are provided for these classes for deciding query entailment. Safe, msafe, and csafe class of quad-systems restrict the structure of blank nodes generated during the chase computation process to be directed acyclic graphs (DAGs) of bounded depth. RR and restricted RR classes do not allow the generation of blank nodes during the chase computation process. Both data and combined complexity of query entailment has been established for the classes derived. We further show that quad-systems are equivalent to forall-existential rules whose predicates are restricted to ternary arity, modulo polynomial time translations. We subsequently show that the technique of safety, strictly subsumes in expressivity, some of the well known and expressive techniques, such as joint acyclicity and model faithful acyclicity, used for decidability guarantees in the realm of forall-existential rules. Content Type Journal Article Pages - DOI 10.3233/SW-140169 Authors Mathew Joseph, FBK-IRST, Via Sommarive 18, 38050, Trento, Italy Gabriel Kuper, DISI, University of Trento, Via Sommarive 5, 38123, Trento, Italy Till Mossakowski, Faculty of Computer Science, Otto-von-Guericke University of Magdeburg, 39016, Magdeburg, Germany. E-mail: {joseph,kuper}@disi.unitn.it, serafini@fbk.eu, mossakow@iws.cs.uni-magdeburg.de Luciano Serafini, FBK-IRST, Via Sommarive 18, 38050, Trento, Italy Journal Semantic Web Online ISSN 2210-4968 Print ISSN 1570-0844

Description: Traditional approaches for querying the Web of Data often involve centralised warehouses that replicate remote data. Conversely, Linked Data principles allow for answering queries live over the Web by dereferencing URIs to traverse remote data sources at runtime. A number of authors have looked at answering SPARQL queries in such a manner; these link-traversal based query execution (LTBQE) approaches for Linked Data offer up-to-date results and decentralised (i.e., client-side) execution, but must operate over incomplete dereferenceable knowledge available in remote documents, thus affecting response times and “recall” for query answers. In this paper, we study the recall and effectiveness of LTBQE, in practice, for the Web of Data. Furthermore, to integrate data from diverse sources, we propose lightweight reasoning extensions to help find additional answers. From the state-of-the-art which (1) considers only dereferenceable information and (2) follows rdfs:seeAlso links, we propose extensions to consider (3) owl:sameAs links and reasoning, and (4) lightweight RDFS reasoning. We then estimate the recall of link-traversal query techniques in practice: we analyse a large crawl of the Web of Data (the BTC'11 dataset), looking at the ratio of raw data contained in dereferenceable documents vs. the corpus as a whole and determining how much more raw data our extensions make available for query answering. We then stress-test LTBQE (and our extensions) in real-world settings using the FedBench and DBpedia SPARQL Benchmark frameworks, and propose a novel benchmark called QWalk based on random walks through diverse data. We show that link-traversal query approaches often work well in uncontrolled environments for simple queries, but need to retrieve an unfeasible number of sources for more complex queries. We also show that our reasoning extensions increase recall at the cost of slower execution, often increasing the rate at which results return; conversely, we show that reasoning aggravates performance issues for complex queries. Content Type Journal Article Pages - DOI 10.3233/SW-140164 Authors Jürgen Umbrich, Vienna University of Economics and Business, Welthandelsplatz 1, 1020 Vienna, Austria. E-mail: jueumb@gmail.com, axel.polleres@wu.ac.at Aidan Hogan, Dept. of Computer Science, Universidad de Chile, Blanco Encalada 2120, Santiago, Chile. E-mail: ahogan@dcc.uchile.com Axel Polleres, Vienna University of Economics and Business, Welthandelsplatz 1, 1020 Vienna, Austria. E-mail: jueumb@gmail.com, axel.polleres@wu.ac.at Stefan Decker, INSIGHT @ NUI Galway, National University of Ireland, Galway, Ireland. E-mail: stefan.decker@deri.org Journal Semantic Web Online ISSN 2210-4968 Print ISSN 1570-0844

Description: Late Papers: RR2010 Special Issue Content Type Journal Article Pages 61-61 Journal Semantic Web Online ISSN 2210-4968 Print ISSN 1570-0844 Journal Volume Volume 6 Journal Issue Volume 6, Number 1 / 2015

Description: Special Issue: The Semantic Web for all Content Type Journal Article Pages 1-1 Journal Semantic Web Online ISSN 2210-4968 Print ISSN 1570-0844 Journal Volume Volume 6 Journal Issue Volume 6, Number 1 / 2015

Description: Various ontology visualization techniques have been developed over the years, offering essential interfaces to users for browsing and interacting with ontologies, in an effort to assist with ontology understanding. Yet few studies have focused on evaluating the usability of existing ontology visualization techniques. This paper presents an eye-tracking user study that evaluates two commonly used ontology visualization techniques, namely, indented list and graph. The eye-tracking experiment and analysis presented in this paper complements the set of existing evaluation protocols for ontology visualization. In addition, the results found from this study contribute to a greater understanding of the strengths and weaknesses of the two visualization techniques, and in particular, how and why one is more effective than the other. Based on approximately 500 MB of eye movement data containing around 30 million rows of gaze data generated by a Tobii eye tracker, we found evidence suggesting indented lists are more efficient at supporting information searches and graphs are more efficient at supporting information processing. Content Type Journal Article Pages - DOI 10.3233/SW-140163 Authors Bo Fu, Department of Computer Science, University of Victoria, Canada Natalya F. Noy, Stanford Center for Biomedical Informatics Research, Stanford University, US Margaret-Anne Storey, Department of Computer Science, University of Victoria, Canada Journal Semantic Web Online ISSN 2210-4968 Print ISSN 1570-0844

Description: The Spatial Information Services Stack Vocabulary Service (SISSVoc) is a Linked Data API for accessing published vocabularies. SISSVoc provides a RESTful interface via a set of URI patterns that are aligned with SKOS. These provide a standard web interface for any vocabulary which uses SKOS classes and properties. The SISSVoc implementation provides web pages for human users, and machine-readable resources for client applications (in RDF, JSON, and XML). SISSVoc is implemented using a Linked Data API façade over a SPARQL endpoint. This approach streamlines the configuration of content negotiation, styling, query construction and dispatching. SISSVoc is being used in a number of projects, mainly in the environmental sciences, where controlled vocabularies are used to support cross-domain and interdisciplinary interoperability. SISSVoc simplifies access to vocabularies for end users, and provides a web API to support vocabulary applications. Content Type Journal Article Pages - DOI 10.3233/SW-140166 Authors Simon J.D. Cox, CSIRO Land and Water, PO Box 56, Highett, Vic. 3190, Australia Jonathan Yu, CSIRO Land and Water, PO Box 56, Highett, Vic. 3190, Australia Terry Rankine, CSIRO Mineral Resources, PO Box 1130, Bentley WA, 6102, Australia. E-mail: {simon.cox,jonathan.yu,terry.rankine}@csiro.au Journal Semantic Web Online ISSN 2210-4968 Print ISSN 1570-0844