anchor.diff:  number of total matching triples. By combining several tpfs, sparql queries are
   evaluated on the client-side, using the metadata for optimization. Hence, we can
   measure the query execution"
  -doctoralconsortium_terziev_7,7,Yordan Terziev,terziev,Feature Generation using Ontologies during Induction of Decision Trees on Linked Data,doctoralconsortium,Session 2,6,Yordan Terziev,DC_Terziev.pdf,,2016-10-18T09:00:00,2016-10-18T17:30:00,"Linked data has the potential of interconnecting data from different domains, bringing new potentials to machine agents to provide better services for web users. The ever increasing amount of linked data in government open data, social linked data, linked medical and patients’ data provides new opportuni-ties for data mining and machine learning. Both are however strongly de-pendent on the selection of high quality data features to achieve good results. In this work we present an approach that uses ontological knowledge to gen-erate features that are suitable for building a decision tree classifier address-ing the specific data set and classification problem. The approach that we present has two main characteristics - it generates new features on demand as required by the induction algorithm and uses ontological knowledge about linked data to restrict the set of possible options. These two characteristics enable the induction algorithm to look for features that might be connected through many entities in the linked data enabling the generation of cross-domain explanation models."
  -doctoralconsortium_ahn_9,9,Jinhyun Ahn,ahn,Optimization Techniques for 2-hop Labeling of Dynamic Directed Acyclic Graphs,doctoralconsortium,Session 2,7,Jinhyun Ahn,DC_Ahn.pdf,,2016-10-18T09:00:00,2016-10-18T17:30:00,"Directed Acyclic Graph(DAG) data is increasingly available on the Web, including Linked Open Data(LOD). Mining reachability relationships between entities is an important task for extracting knowledge from LOD. Diverse labeling schemes have been proposed to efficiently determine the reachability. We focus on a state-of-the-art 2-hop labeling scheme that is based on a permutation of vertices to achieve a linear index size and reduce on-line searches that are required when the reachability cannot be answered by 2-hop labels only. We observed that the approach can be improved in three different ways; 1) space-efficiency - guarantee the minimized index size without randomness 2) update-efficiency - update labels efficiently when graphs changes 3) parallelization - labeling should be cluster-based, and solved in a distributed fashion. In these regards, this PhD thesis proposes optimization techniques that address these issues. In this paper in particular, a way of reducing the 2-hop label size is proposed with preliminary results on real-world DAG datasets. In addition, we will discuss the feasibilities of the other issues based on our on-going works."
  -doctoralconsortium_ren_11,11,Xiangnan Ren,ren,"Towards a distributed, scalable and real-time RDF Stream Processing engine",doctoralconsortium,Session 2,8,Xiangnan Ren,DC_Ren.pdf,,2016-10-18T09:00:00,2016-10-18T17:30:00,"Due to the growing need to timely process and derive valuable information and knowledge from data produced in the Semantic Web, RDF stream processing (RSP) has emerged as an important research domain. Of course, modern RSP have to address the volume and velocity characteristics encountered in the Big Data era. This comes at the price of designing high throughput, low latency, fault tolerant, highly available and scalable engines. The cost of implementing such systems from scratch is very high and usually one prefers to program components on top of a framework that possesses these properties, e.g., Apache Hadoop or Apache Spark. The research conducting in this PhD adopts this approach and aims to create a production-ready RSP engine which will be based on domain standards, e.g., Apache Kafka and Spark Streaming. In a nutshell, the engine aims to i) address basic event modeling - to guarantee the completeness of input data in window operators, ii) process real-time RDF stream in a distributed manner - efficient RDF stream handling is required; iii) support and extend common continuous SPARQL syntax - easy-to-use, adapt to the industrial needs and iv) support reasoning services at both the data preparation and query processing levels."
  -doctoralconsortium_georgala_2,2,Kleanthi Georgala,georgala,Scalable Link Discovery for Modern Data-Driven Applications,doctoralconsortium,Session 2,9,Kleanthi Georgala,DC_Georgaia.pdf,,2016-10-18T09:00:00,2016-10-18T17:30:00,"Modern data-driven applications often have to integrate and process large volumes of high-velocity data. To this end, they require fast and accurate Link Discovery solutions. Most Link Discovery frameworks rely on complex link specifications to determine candidates for links. Hence, the main focus of this work lies in the conception, development, implementation and evaluation of time-efficient and scalable Link Discovery approaches based on the link specification paradigm. We address the aforementioned challenges by presenting approaches for (1) time-constrained linking and (2) for the efficient computation and (3) scalable execution of link specifications with applications to periodically updated knowledge bases. The overall result of this thesis will be an open-source framework for link discovery on large volumes of RDF data streams."
  -doctoralconsortium_masuda_12,12,Takeshi Masuda,masuda,Ontology Refinement and Evaluation System based on Similarity of Is-a Hierarchies,doctoralconsortium,Session 3,10,Takeshi Masuda,DC_Masuda,,2016-10-18T09:00:00,2016-10-18T17:30:00,"Ontologies are constructed in various fields such as medical information, mechanical design, and etc. It is important to build high quality ontologies so that these ontologies are used as knowledge bases and knowledge models for application systems. However it is hard to build good quality ontologies because of the necessity of both knowledge of ontology and expertise in their target domain. For this background, ontology construction and refinement costs a lot of time and ef-fort. In order to reduce such costs, we develop an ontology refinement support system. This system have two main function. First, the system can detect points that should be refined and propose how to refine it. Second, the system can evaluate ontologies quantitatively. This system indicate how ontologies are consistent in a classificatory criterion. To develop the refinement support system, we focus on a guideline for building well-organized ontologies that “Each subclass of a super class is distinguished by the values of exactly one attribute of the super class”. When an ontology is built following this guideline, there is similarity among Is-a hierarchies. We use these similar Is-a hierarchies and develop an ontology refinement system."
  -doctoralconsortium_ivanova_4,4,Valentina Ivanova,ivanova,Applications of Large Displays: Advancing User Support in Large Scale Ontology Alignment,doctoralconsortium,Session 3,11,Valentina Ivanova,DC_Ivanova.pdf,,2016-10-18T09:00:00,2016-10-18T17:30:00,"Producing alignments of highest quality requires ‘humans in the loop’, however, user involvement is currently one of the challenges for the ontology alignment community. Ontology alignment is a cognitively intensive task and could be efficiently supported by user interfaces encompassing well-designed visualizations and interaction techniques. This work investigates the application of large, high-resolution displays to improve users’ cognitive support and identifies several promising directions for their application—improving ontologies’ and alignments’ navigation, supporting users’ thinking process and collaboration."
  -doctoralconsortium_neumaier_13,13,Sebastian Neumaier,neumaier,Improving Open Data Usability through Semantics,doctoralconsortium,Session 3,12,Sebastian Neumaier,DC_Neumaier.pdf,,2016-10-18T09:00:00,2016-10-18T17:30:00,"With the success of Open Data a huge amount of tabular data become available that could potentially be mapped and linked into the Web of (Linked) Data. The use of semantic web technologies would then allow to explore related content and enhanced search functionalities across data portals. However, existing linkage and labeling approaches mainly rely on mappings of textual information to classes or properties in knowledge bases. In this work we outline methods to recover the semantics of tabular Open Data and to identify related content which allows a mapping and automated integration/categorization of Open Data resources and improves the overall usability and quality of Open Data."
  -doctoralconsortium_van_herwegen_8,8,Joachim Van Herwegen,van herwegen,Querying Distributed Heterogeneous Linked Data Interfaces through Reasoning,doctoralconsortium,Session 3,13,Joachim Van Herwegen,DC_VanHerwegen.pdf,,2016-10-18T09:00:00,2016-10-18T17:30:00,"Linked Data can be distributed through multiple interfaces on the Web,
  +poster_76,76,Octavian Rinciog and Vlad Posea,Rinciog,GovLOD: Towards to a Linked Open Data Portal,poster,Poster and Demo session,97,Octavian Rinciog,poster_76.pdf,3rd Floor,2016-10-19T18:00:00,2016-10-19T21:00:00,"Nowadays, governments and public agencies publish open data at an exponentially growing rate on dedicated portals. These open data have a problem: they don’t have a well defined structure, because the focus is on publishing data and not on how they are used. GovLOD is a platform that aims to transform the information found in these heterogeneous files in Linked Open Data using RDF triples."
  +poster_70,70,"Ran Yu, Besnik Fetahu, Ujwal Gadiraju and Stefan Dietze",Yu,A Survey on Challenges in Web Markup Data for Entity Retrieval,poster,Poster and Demo session,98,Ran Yu,poster_70.pdf,3rd Floor,2016-10-19T18:00:00,2016-10-19T21:00:00,"Embedded markup based on Microdata, RDFa, and Microformats have become prevalent on the Web and constitute an unprecedented data source. RDF statements from markup are highly redundant, co-references are very frequent yet explicit links are missing, and with numerous errors in such statements.
  +
  +We present a thorough analysis on the challenges associated with markup data in the context of entity retrieval. We analyze four main factors: (i) co-references, (ii) redundancy, (iii) inconsistencies, and (iv) accessibility of information in the case of URLs. We conclude with general guidelines on how to avoid such challenges when dealing with embedded markup data."
  +research_305,305,"Allan Third, George Gkotsis, Eleni Kaldoudi, George Drosatos, Nick Portokallidis, Stefanos Roumeliotis, Kalliopi Pafilis and John Domingue",Third,Integrating medical scientific knowledge with the semantically Quantified Self,research,Medical Applications,1,Allan Third,research_305.pdf,501,2016-10-21T13:30:00,2016-10-21T13:50:00,"The assessment of risk in medicine is a crucial task, depending on scientific knowledge derived by rigorous clinical studies regarding the (quantified) factors affecting biological changes, as well as on particular knowledge about the current status of a particular patient. Existing non-semantic risk prediction tools are typically based on hardcoded scientific knowledge, and only cover a very limited range of patient states. This makes them rapidly out of date, and limited in application, particularly for patients with co-morbidities (multiple co-occurring conditions). Semantic Web and Quantified Self technologies make it possible to address this task in a much more principled way, to maximise knowledge and data reuse and minimise maintenance requirements while enabling new and sophisticated applications involving widely-available biometric sensors. 
  +
  +We present a framework for calculating clinical risk predictions for patients based on automatically-gathered biometric data. This framework relies on generic, reusable ontologies for representing clinical risk, and sensor readings, and reasoning to support the integration of data represented according to these ontologies. This integration makes novel use of Semantic Web technologies, and supports straightforward extension and maintenance by medical professionals. The framework is evaluated in terms of its predictions, extensibility and ease of use for domain experts."
  +poster_72,72,David Martin and Peter Patel-Schneider,Martin,EXISTStential Aspects of SPARQL,poster,Poster and Demo session,99,David Martin,poster_72.pdf,3rd Floor,2016-10-19T18:00:00,2016-10-19T21:00:00,"The SPARQL 1.1 Query Language \cite{SPARQL} permits patterns inside {\sf FILTER}
  +expressions using the {\sf EXISTS} construct, specified by using substitution.
  +Substitution destroys some of the aspects of SPARQL that make
  +it suitable as a data access language. As well, substitution causes
  +problems in the SPARQL algebra and produces counterintuitive results.
  +Fixing the problems with {\sf EXISTS} is best done with a completely different
  +definition that does not use substitution at all."
  +research_210,210,"Steven de Rooij, Wouter Beek, Stefan Schlobach and Frank Van Harmelen",Rooij,Are Names Meaningful? Quantifying Social Meaning on the Semantic Web,research,Linked Data Measurement,1,Steven de Rooij,research_210.pdf,504+505,2016-10-20T13:30:00,2016-10-20T13:50:00,"According to Semantic Web standards, IRIs are individual
  +constants or predicate letters whose names are chosen arbitrarily
  +and carry no formal meaning. At the same time it is a well-known
  +aspect of Semantic Web pragmatics that IRIs are often constructed
  +mnemonically, in order to be meaningful to a human interpreter.
  +The latter has traditionally been termed 'Social Meaning', a
  +concept that has been discussed but not yet quantitatively
  +studied by the Semantic Web community.
  +
  +In this paper we use statistical model learning as a method to
  +quantify the meaning that is (at least) encoded in Semantic Web
  +names, We implement the approach and evaluate it over hundreds of
  +thousands of data sets in order to illustrate its efficacy. Our
  +experiments confirm that many Semantic Web names are indeed
  +meaningful and, more interestingly, we provide a quantitative
  +lower bound on how much meaning is (at least) encoded in names on
  +a per-dataset basis.
  +
  +To our knowledge, this is the first paper about the interaction
  +between social and formal meaning, as well as the first paper
  +that uses statistical model learning as a method to quantify
  +meaning in the Semantic Web context.
  +"
  +resource_37,37,"Stefano Faralli, Alexander Panchenko, Chris Biemann and Simone Paolo Ponzetto",Faralli,Linked Disambiguated Distributional Semantic Networks,resource,Natural Language Processing,1,Stefano Faralli,resource_37.pdf,504+505,2016-10-21T10:30:00,2016-10-21T10:50:00,"We present a new hybrid knowledge base that combines the contextual information of distributional models with the conciseness and precision of manually constructed lexical networks. In contrast to dense vector representations, our resource is human readable and interpretable, and can be easily embedded within the Semantic Web ecosystem. Manual evaluation based on human judgments and an extrinsic evaluation on the task of Word Sense Disambiguation both indicate the high quality of the resource, as well as the benefits of enriching top-down lexical knowledge resources with bottom-up distributional information from text."
  +doctoralconsortium_12,12,Joachim Van Herwegen,Herwegen,Querying Distributed Heterogeneous Linked Data Interfaces through Reasoning,doctoralconsortium,Session 3,4,Joachim Van Herwegen,doctoralconsortium_12.pdf,,2016-10-18T16:45:00,2016-10-18T17:00:00,"Linked Data can be distributed through multiple interfaces on the Web,
   each of them with their own expressivity.
   However, there is no generic client available that can handle querying over multiple interfaces.
   This increases the complexity of combining datasets and designing new interfaces.
  
positive.code: system performance and device resources depending on their availability. The
  adaptation model is based on the resource cost model of the data management
  techniques."
  doctoralconsortium_vander_sande_6,6,Miel Vander Sande,vander sande,Studying Metadata for better client-server trade-offs in Linked Data publishing,doctoralconsortium,Session 2,5,Miel Vander Sande,DC_VanderSande.pdf,,2016-10-18T09:00:00,2016-10-18T17:30:00,"Client-server trade-offs can be analyzed using Linked Data Fragments,
  which proposes an uniform view on all interfaces to rdf. This reveals a complete
  spectrum between Linked Data documents and the sparql protocol, in which
  we can advance the state-of-the-art of Linked Data publishing. This axis can be
  
negative.code: study this issue for several classes of existential rules and derive more 
  general syntactic criteria to recognise well-behaved rule-based ontologies
  over knowledge graphs."
  demo_3,3,Ghislain Auguste Atemezing and Pierre-Yves Vandenbussche,Atemezing,QA4LOV: A Natural Language Interface to Linked Open Vocabulary,demo,Poster and Demo session,101,Ghislain Auguste Atemezing,demo_3.pdf,3rd Floor,2016-10-19T18:00:00,2016-10-19T21:00:00,"There is an increasing presence of structured data due to the adoption of Linked data principles on the web. At the same time, web users have different skills and want to be able to interact with Linked datasets in various manner, such as asking questions in natural language. Over the last years, the QALD challenges series are becoming the references for benchmarking question answering systems. However, QALD questions are targeted on datasets, not on vocabulary catalogues. This paper proposed a first implementation of Query Answering system (QA) applied to the Linked Open Vocabularies (LOV) catalogue, mainly focused on metadata information retrieval. The goal is to provide to end users yet another access to metadata information available in LOV using natural language questions."
  demo_6,6,"Ruben Taelman, Pieter Heyvaert, Ruben Verborgh, Erik Mannens and Rik Van de Walle",Taelman,Querying Dynamic Datasources with Continuously Mapped Sensor Data,demo,Poster and Demo session,102,Ruben Taelman,demo_6.pdf,3rd Floor,2016-10-19T18:00:00,2016-10-19T21:00:00,"The world contains a large amount of sensors that produce new data at a high frequency. It is currently very hard to find public services that expose these measurements as dynamic Linked Data, We investigate how sensor data can be published continuously on the Web at a low cost. This paper describes how the publication of various sensor data sources can be done by continuously mapping raw sensor data to RDF and inserting it into a live, low-cost server. This makes it possible for clients to continuously evaluate dynamic queries using public sensor data. For our demonstration, we will illustrate how this pipeline works for the publication of temperature and humidity data originating from a microcontroller, and how it can be queried."
  research_110,110,"Chetana Gavankar, Yuan-Fang Li and Ganesh Ramakrishnan",Gavankar,Explicit Query Interpretation and Diversification for Context-driven Concept Search across Ontologies,research,Search (I),1,Chetana Gavankar,research_110.pdf,502,2016-10-20T13:30:00,2016-10-20T13:50:00,"Finding relevant concepts from a corpus of ontologies is useful in many scenarios, including document classification, web page annotation, and automatic ontology population. Millions of concepts are contained in a large number of ontologies across diverse domains. SPARQL-based query demands knowledge of the structure of ontologies and the query language, whereas more user-friendly, simple keyword-based approaches suffer from false positives as concept descriptions in ontologies may be ambiguous and overlapping. In this paper, we propose a keyword-based concept search framework that (1) exploits the structure and semantics in ontologies, by constructing contexts for each concept; (2) generates the interpretations of a query; and (3) balances relevance and diversity of search results. A comprehensive evaluation against both the domain-specific BioPortal and the general-purpose Falcons on widely-used performance metrics demonstrates that our system outperforms both."
  research_115,115,Melisachew Wudage Chekol and Giuseppe Pirrò,Chekol,Containment of Expressive SPARQL Navigational Queries,research,Querying,2,Melisachew Wudage Chekol,research_115.pdf,502,2016-10-19T14:20:00,2016-10-19T14:40:00,"Query containment is one of the building block of query optimization techniques. In the relational world, query containment is a well-studied problem. At the same time it is well-understood that relational queries are not enough to cope with graph-structured data, where one is interested in expressing queries that capture navigation in the graph. This paper contributes a study on the problem of query containment for an expressive class of navigational queries called Extended Property Paths (EPPs). EPPs are more expressive than previous navigational extensions of SPARQL like property paths and nested regular expressions, for which containment has already been studied. We attack the problem of EPPs (and SPARQL with EPPs) containment and provide complexity bounds.
  "
  research_119,119,"Shen Gao, Daniele Dell'Aglio, Soheila Dehghanzadeh, Abraham Bernstein, Emanuele Della Valle and Alessandra Mileo",Gao,Planning Ahead: Stream-Driven Linked-Data Access under Update-Budget Constraints,research,Streams,1,Shen Gao,research_119.pdf,501,2016-10-20T13:30:00,2016-10-20T13:50:00,"Data stream applications are becoming increasingly popular on the web. In these applications, one query pattern is especially prominent: a join between a continuous data stream and some background data (BGD). Oftentimes, the target BGD is large, maintained externally, changing slowly, and costly to query (both in terms of time and money). Hence, practical applications usually maintain a local (cached) view of the relevant BGD. Given that these caches are not updated as part of the transaction modifying the original BGD, they should be maintained under realistic budget constraints (in terms of latency, computation time, and possibly financial cost) to avoid stale data leading to wrong answers. 
  
  This paper proposes to model the join between streams and the BGD as a bipartite graph. By exploiting the graph structure, we keep the quality of results good enough without refreshing the entire cache for each evaluation. We also introduce two extensions to this method: first, we consider both the sliding window (specifying the currently relevant section of the data stream) and the change rate of the BGD to focus on updates that have the longest effect. Second, by considering the future impact of a query to the BGD we propose to sometimes delay updates to provide more fresher answers in future.
  
  Using an implemented system we empirically show that we can improve result freshness by 93% over baseline algorithms such as Random Selection or Least Recently Updated."
  