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Matches in ScholarlyData for { ?s <https://w3id.org/scholarlydata/ontology/conference-ontology.owl#abstract> ?o. }

• 77 abstract "This paper aims to show how language-related knowledge may serve as a fundamental building block for the Semantic Web. We present a system of URIs for terms, languages, scripts, and characters, which are not only highly interconnected but also linked to a great variety of resources on the Web. Additional mapping heuristics can then be used to derive new links.".
• 78 abstract "Since Wikipedia has become a huge scale database storing wide-range of human knowledge, it is a promising corpus for knowledge extraction. A considerable number of researches on Wikipedia mining have been conducted and the fact that Wikipedia is an invaluable corpus has been conrmed. Wikipedia's impressive characteristics are not limited to the scale, but also include the dense link structure, URI for word sense disambiguation, well structured Infoboxes, and the category tree. One of the popular approaches in Wikipedia Mining is to use Wikipedia's category tree as an ontology and a number of researchers proved that Wikipedia's categories are promising resources for ontology construction by showing significant results. In this work, we try to prove the capability of Wikipedia as a corpus for knowledge extraction and how it works in the Semantic Web environment. We show two achievements; Wikipedia Thesaurus, a huge scale association thesaurus by mining the Wikipedia's link structure, and Wikipedia Ontology, a Web ontology extracted by mining Wikipedia articles.".
• 8 abstract "In this paper we present our hypothesis that transition to semantic file system interfaces is possible by computing the organization of hierarchical file systems from semantic web data.".
• 80 abstract "In this poster, we describe the actual state of development of ontology learning/extraction, which is currently being designed and implemented in the context of a large European R&D project dealing with Business Intelligence applications. We propose an approach to the extension of existing domain ontologies or even to the semi-automatic ontology creation from scratch, on the base of a multi-layered processing of textual documents.".
• 81 abstract "We present LENA, a web-based RDF browser that supports the rendering of complex RDF data based on criteria expressed as SPARQL queries. The user interface of LENA enables to switch between different views onto the presented data enabling users to browse the data with respect to individual interests or expertise.".
• 82 abstract "The fast-growing Web 2.0 applications promote explicit so- cial structure and explosive data on the Web, and enable the realization of social webtops, where users use web ap- plications to collaboratively organize and share online data. In this work, we show that semantic wiki technologies are suitable for building a social webtop. We also identify two key issues in realizing social webtop applications on seman- tic wiki and present our initial investigation with live demos: (i) popular concept modeling mechanisms used by webtop applications can be supported by semantic wiki; and (ii) provenance-aware data personalization mechanisms can be added as semantic wiki extensions to better support collab- orative data management on a webtop.".
• 83 abstract "The vision of the Semantic Web is to make use of semantic representations on the largest possible scale - the Web. Large knowledge bases such as DBpedia, OpenCyc, GovTrack, and others are emerging and are freely available as Linked Data and SPARQL endpoints. Exploring and analysing such knowledge bases is a significant hurdle for Semantic Web research and practice. As one possible direction for tackling this problem, we present an approach for obtaining complex class descriptions from objects in knowledge bases by using Machine Learning techniques. We describe how we leverage existing techniques to achieve scalability on large knowledge bases available as SPARQL endpoints or Linked Data. Our algorithms are made available in the open source DL-Learner project and can be used in real-life scenarios by Semantic Web applications.".
• 84 abstract "We present ontologydesignpatterns.org (ODP), a semantic web portal about ontology design patterns based on wiki technology, which aims at supporting a community around best practices for ontology design. ODP offers services for evaluation and training about ontology patterns, and a repository of OWL ontologies. ODP fosters several kinds of participation, from anonymous, read-only access to open-rating and quality-committee membership. Based on semantic wiki components, we have developed EvalWF, an extension for supporting evaluation workflows able to manage the entire lifecycle of a pattern, from submission to certification.".
• 85 abstract "This paper presents TagCare as a tool which allows users to maintain their personal tagging vocabulary and to carry it along different platforms. TagCare collects the tags which a user has applied within several social software tools. These personal tags may be edited and structured, e.g. interrelated with hierarchical and other semantic relations.".
• 86 abstract "Many Semantic Wiki Engines have been developed in response to a semi-structured domain of application. Nevertheless these engines take very few advantages of the structured model on their viewing and editing interfaces. In this paper we present HyperDEWiki implementation where we combine Semantic Wiki and model-based Semantic Web Application allowing specialized interfaces and navigation. The tool is also intended to support domain ontology evolution.".
• 87 abstract "Recommender systems play an important role in support- ing people when choosing items from a overwhelming huge number of choices. So far, no recommender system makes use of domain knowledge. We are modeling user prefer- ences with a machine learning approach to recommend peo- ple items by predicting the item ratings. Specifically, we pro- pose SemTree, an ontology-based decision tree learner, that uses a reasoner and an ontology to semantically generalize item features to improve the effectiveness of the decision tree built. We show that SemTree outperforms comparable ap- proaches in recommending more accurate recommendations considering domain knowledge.".
• 88 abstract "This poster presents a programmatic interface (SKOS API) and plugin for Protege 4 for editing and working with the Simple Knowledge Organisation System (SKOS). The SKOS API has been designed to work with SKOS models at a high level of abstraction to aid developers of applications that use SKOS. We discuss SKOSEd, a tool for authoring and editing SKOS artefacts. A key aspect to the design of the API and editor is how SKOS relates to OWL and what existing OWL infrastructure can be exploited to work with SKOS.".
• 89 abstract "Knowledge sharing is vital in collaborative work environments, and sharing resources within a contextual knowledge structure constructed based on a collective intelligence of the people working in a same environment can aid better communication. In this paper, we discuss a semantic knowledge structure for effective knowledge shraing and communication, and present a Wiki-based knowledge sharing system for research projects with effective navigation means.".
• 9 abstract "Thinkbase is a visual navigation and exploration tool for Freebase, an open, shared database of the world’s knowledge. Thinkbase extracts the contents, including semantic relationships, from Freebase and visualizes them using an interactive visual representation. Providing a focus plus context view the visualization is displayed along with the Freebase article. Thinkbase provides a proof of concept of how visualizations can improve and support Semantic Web applications. The application is available via http://thinkbase.cs.auckland.ac.nz.".
• 90 abstract "Last summer, we represented the 1200 species observations of the First Annual Blogger Bioblitz in RDF. This allowed us to easily integrate the data with existing RDF data on natural history, taxonomy, food webs, conservation status, and invasive status. Using our Swoogle/Tripleshop approach to dataset construction, we were able to respond to a variety of ad-hoc queries Our efforts last year were external to the running of the bioblitz. For this year’s blogger bioblitz (late August), we have taken responsibility for data processing, and will encourage participants to make use of two tools we have developed that ease the process of user-generated RDF – the Spotter Firefox plug-in, and RDF123. We will encourage ISWC participants to photo-blog Karlsruhe wildlife during the conference, and to use Spotter to generate RDF of their posts. We will also attempt a full bioblitz of a suitable area near the Conference Centre. Our demo will allow users to browse the dataspace resulting from all observations, together with background data, and to issue SPARQL queries over the data.".
• 100 abstract "A number of ontology repositories provide access to the growing collection of ontologies on the Semantic Web. Some repositories collect ontologies automatically by crawling the Web; in other repositories, users submit ontologies themselves. In addition to providing search across multiple ontologies, the added value of ontology repositories lies in the metadata that they may contain. This metadata may include information provided by ontology authors, such as ontologies’ scope and intended use; feedback provided by users such as their experiences in using the ontologies or reviews of the content; and mapping metadata that relates concepts from different ontologies. In this paper, we focus on the ontology-mapping metadata and on community-based method to collect ontology mappings. More specifically, we develop a model for representing mappings collected from the user community and the metadata associated with the mapping. We use the model to bring together more than 30,000 mappings from 7 sources. We also validate the model by extending BioPortal—a repository of biomedical ontologies that we have developed—to enable users to create single concept-to-concept mappings in its graphical user interface, to upload and download mappings created with other tools, to comment on the mappings and to discuss them, and to visualize the mappings and the corresponding metadata.".
• 103 abstract "As with the decentralized nature of the Semantic Web, a lot of terms (classes and properties) have been published by various parties, to be shared for describing resources. Terms are usually defined based on other terms, and thus a directed dependence relation is formed. The study of term dependence is a foundation work and is important for many other tasks, such as ontology search, maintenance, and distributed reasoning on the Web scale. In this paper, we propose a notion of term dependence on the Semantic Web, and analyze the complex network characteristics of the term dependence graph and the vocabulary dependence graph. The graphs analyzed in our experiments are constructed from a data set that contains 1,278,233 terms in 3,039 vocabularies. The results characterize the current status of schemas on the Semantic Web in many aspects, including degree distributions, reachability, and connectivity.".
• 115 abstract "There are many reasons for measuring a distance between ontologies. In particular, it is useful to know quickly if two ontologies are close or remote before deciding to match them. To that extent, a distance between ontologies must be quickly computable. We present constraints applying to such measures and several possible ontology distances. Then we evaluate experimentaly some of them in order to assess their accuracy and speed.".
• 122 abstract "Integration of heterogeneous services is often hard-wired in service or workflow implementations. In this paper we define an execution model operating on semantic descriptions of services allowing flexible integration of services with solving data and process conflicts where necessary. We implement the model using our WSMO technology and a case scenario from the B2B domain and evaluate the model according to the SWS Challenge criteria.".
• 124 abstract "We analyze the datatype system of OWL and OWL 2, and discuss certain nontrivial consequences of its definition, such as the extensibility of the set of supported datatypes and complexity of reasoning. We also argue that certain datatypes from the list of normative datatypes in the current OWL 2 Working Draft are inappropriate and should be replaced with different ones. Finally, we present an algorithm for datatype reasoning. Our algorithm is modular in the sense that it can handle any datatype that supports certain basic operations. We show how to implement these operations for number and string datatypes.".
• 13 abstract "In this paper, we present a framework for developing ontologies in a modular manner, which is based on the notions of interfaces and knowledge encapsulation. Within the context of this framework, an ontology can be defined and developed as a set of ontology modules that can access the knowledge bases of the others through their well-defined interfaces. An important implication of the proposed framework is that ontology modules can be developed completely independent of each others’ signature and language. Such modules are free to only utilize the required knowledge segments of the others. We describe the interface-based modular ontology formalism, which theoretically supports this framework and present its valuable features compared to the exiting modular ontology formalisms. We also describe the real-world design and implementation of the framework for creating modular ontologies by extending OWL-DL, Swoop interfaces and reasoner.".
• 138 abstract "The emerging paradigm of service-oriented computing requires novel techniques for various service-related tasks. Along with automated support for service discovery, selection, negotiation, and composition, support for automated service contracting and enactment is crucial for any large scale service environment, where large numbers of clients and service providers interact. Many problems in this area involve reasoning, and a number of logic-based methods to handle these problems have emerged in the field of Semantic Web Services. In this paper, we build upon our previous work where we used Concurrent Transaction Logic (CTR) to model and reason about service contracts. We significantly extend the modeling power of the previous work by allowing iterative processes in the specification of service contracts, and we extend the proof theory of CTR to enable reasoning about such contracts. With this extension, our logic-based approach is capable of modeling general services represented using languages such as WS-BPEL.".
• 143 abstract "Correspondences in ontology alignments relate two ontology entities with a relation. Typical relations are equivalence or subsumption. However, different systems may need different kinds of relations. We propose to use the concepts of algebra of relations in order to express the relations between ontology entities in a general way. We show the benefits in doing so in expressing disjunctive relations, merging alignments in different ways, amalgamating alignments with relation sets of different granularity, and composing alignments.".
• 160 abstract "The growing popularity of social tagging systems promises to alleviate the knowledge bottleneck that slows the full materialization of the Semantic Web, as these systems are cheap, extendable, scalable and respond quickly to user needs. However, for the sake of knowledge workflow, one needs to find a compromise between the ungoverned nature of folksonomies and the controlled vocabulary of domain-experts. In this paper, we address this concern by first devising a method that automatically combines folksonomies with domain-expert ontologies resulting in an enriched folksonomy. We then introduce a new algorithm based on frequent itemsets mining that efficiently learns an ontology over the concepts present in the enriched folksonomy. Moreover, we propose a new benchmark for ontology evaluation, which is used in the context of information finding, since this is one of the leading motivations for using ontologies in social tagging systems, to quantitatively assess our method. We conduct experiments on real data and empirically show the effectiveness of our approach.".
• 172 abstract "The continued increase in Web usage, in particular participation in folksonomies, reveals a trend towards a more dynamic and interactive Web where individuals can organise and share resources. Tagging has emerged as the de-facto standard for the organisation of such resources, providing a versatile and reactive knowledge management mechanism that users find easy to use and understand. It is very common nowadays for users to have multiple profiles in various folksonomies, thus distributing their tagging activities. In this paper, we present a method for the automatic consolidation of user profiles accross two popular social networking sites, and subsequent semantic modelling of their interests utilising Wikipedia as a multi-domain model. We evaluate how much can be learned from such sites, and where the knowledge acquired is focussed. Results show that far richer interest profiles can be generated for users when their multiple tag clouds are combined.".
• 177 abstract "Collaborative tagging systems have nowadays become important data sources for populating semantic web applications. For tasks like synonym detection and discovery of concept hierarchies, many researchers introduced measures of tag similarity. Even though most of these measures appear very natural, their design often seems to be rather ad hoc, and the underlying assumptions on the notion of similarity are not made explicit. A more systematic characterization and validation of tag similarity in terms of formal representations of knowledge is still lacking. Here we address this issue and anayze several measures of tag similarity: Each measure is computed on data from the social bookmarking system del.icio.us and a semantic grounding is provided by mapping pairs of similar tags in the folksonomy to pairs of synsets in Wordnet, where we use validated measures of semantic distance to characterize the semantic relation between the mapped tags. This exposes important features of the investigated measures and indicates which measures are better suited in the context of a given semantic application.".
• 178 abstract "Efficient RDF data management is one of the cornerstones in realizing the Semantic Web vision. In the past, different RDF storage strategies have been proposed, ranging from simple triple stores to more advanced techniques like clustering or vertical partitioning on the predicates. We present an experimental comparison of existing storage strategies on top of the SP^2Bench SPARQL performance benchmark suite and put the results into context by comparing them to a purely relational model of the benchmark scenario. We observe that (1) in terms of performance and scalability, a simple triple store built on top of a column-store DBMS is competitive to the vertically partitioned approach when choosing a physical (predicate, subject, object) sort order, (2) in our scenario with real-world queries, none of the approaches scales to documents containing tens of millions of RDF triples, and (3) none of the approaches yet can compete with a purely relational model. We conclude that future research is necessary to further bring forward RDF data management.".
• 180 abstract "Various semantic web service discovery techniques have been proposed, many of which perform the profile based service signature (I/O) matching. However, the service I/O concepts are not sufficient to discover web service accurately. This paper suggests a new method to enhance the semantic description of semantic web service by using the semantic constraints of service I/O concepts in specific context. The semantic constraints described in a constraint graph are extracted automatically from the parsing results of the service description text by a set of heuristic rules. The corresponding semantic web service matchmaker performs not only the profile’s semantic matching but also the matching of their semantic constraints with the help of a constraint graph based matchmaking algorithm. The experiment results are encouraging when applying the semantic constraint to discover semantic web services on the service retrieval test collection OWLS-TC v2.".
• 19 abstract "We study the problem of distributed RDFS reasoning and query answering on top of distributed hash tables. Scalable, distributed RDFS reasoning is an essential functionality for providing the scalability and performance that large-scale Semantic Web applications require. Our goal in this paper is to compare and evaluate two well-known approaches to RDFS reasoning, namely backward and forward chaining, on top of distributed hash tables. We show how to implement both algorithms on top of the distributed hash table Bamboo and prove their correctness. We also study the time-space trade-off exhibited by the algorithms analytically, and experimentally by evaluating our algorithms on PlanetLab.".
• 192 abstract "The Semantic Desktop is a means to support users in Personal Information Management (PIM). Using the open source software prototype Gnowsis, we evaluated the approach in a two month case study in 2006 with eight participants. Two participants continued using the prototype and were interviewed after two years in 2008 to show their long-term usage patterns. This allows us to analyse how the system was used for PIM. Contextual interviews gave insights on behaviour, while questionnaires and event logging did not. We discovered that in the personal environment, simple has-part and is-related relations are sufficient for users to file and re-find information, and that the personal semantic wiki was used creatively to note information.".
• 194 abstract "The Semantic Web is a distributed environment for knowledge representation and reasoning. The distributed nature brings with it failing data sources and inconsistencies between autonomous knowledge bases. To reduce problems resulting from unavailable sources and to improve performance, caching can be used. Caches, however, raise new problems of imprecise or outdated information. We propose to distinguish between certain and cached information when reasoning on the semantic web, by extending the well known FOUR bilattice of truth and knowledge orders to FOUR-C, taking into account cached information. We discuss how users can be offered additional information about the reliability of inferred information, based on the availability of the corresponding information sources. We then extend the framework towards FOUR-T , allowing for multiple levels of trust on data sources. In this extended setting, knowledge about trust in information sources can be used to compute, how well an inferred statement can be trusted and to resolve inconsistencies arising from connecting multiple data sources. We redefine the stable model and well founded semantics on the basis of FOUR-T, and reformalize the Web Ontology Language OWL2 based on logical bilattices, to augment OWL knowledge bases with trust based reasoning.".
• 197 abstract "We introduce the notion of the mixed DL and entailment-based (DLE) OWL reasoning, defining a framework inspired from the hybrid and homogeneous paradigms for integration of rules and ontologies. The idea is to combine the TBox inferencing capabilities of the DL algorithms and the scalability of the rule paradigm over large ABoxes. Towards this end, we define a framework that uses a DL reasoner to reason over the TBox of the ontology (hybrid-like) and a rule engine to apply a domain-specific version of ABox-related entailments (homogeneous-like) that are generated by TBox queries to the DL reasoner. The DLE framework enhances the entailment-based OWL reasoning paradigm in two directions. Firstly, it disengages the manipulation of the TBox semantics from any incomplete entailment-based approach, using the efficient DL algorithms. Secondly, it achieves faster application of the ABox-related entailments and efficient memory usage, comparing it to the conventional entailment-based approaches, due to the low complexity and the domain-specific nature of the entailments.".
• 210 abstract "For easing the exchange of news, the International Press Telecommunication Council (IPTC) has developed the NewsML Architecture (NAR), an XML-based model that is specialized into a number of languages such as NewsML G2 and EventsML G2. As part of this architecture, specific controlled vocabularies, such as the IPTC News Codes, are used to categorize news items together with other industry-standard thesauri. While news is still mainly in the form of text-based stories, these are often illustrated with graphics, images and videos. Media-specific metadata formats, such as EXIF, DIG35 and XMP, are used to describe the media. The use of different metadata formats in a single production process leads to interoperability problems within the news production chain itself. It also excludes linking to existing web knowledge resources and impedes the construction of uniform end-user interfaces for searching and browsing news content. In order to allow these different metadata standards to interoperate within a single information environment, we design an OWL ontology for the IPTC News Architecture, linked with other multimedia metadata standards. We convert the IPTC NewsCodes into a SKOS thesaurus and we demonstrate how the news metadata can then be enriched using natural language processing and multimedia analysis and integrated with existing knowledge already formalized on the Semantic Web. We discuss the method we used for developing the ontology and give rationale for our design decisions. We provide guidelines for re-engineering schemas into ontologies and formalize their implicit semantics. In order to demonstrate the appropriateness of our ontology infrastructure, we present an exploratory environment for searching and browsing news items.".
• 216 abstract "This paper presents a new semantic relatedness measure on an ontology which consider especially the object properties between the concepts. Our approach relies on two hypotheses. Firstly, using only concept hierarchy and object properties, only a few numbers of paths can be considered as ``semantically correct'' and these paths obey to a given set of rules. Secondly, following a given edge in a path has a cost (represented as a weight), which depends on its type (is-a, part-of, etc.), its context in the ontology and its position in the path. We propose an evaluation of our measure on the lexical base WordNet using part-of relation with two different benchmarks. We show that, in this context, our measure outperforms the classical semantic measures.".
• 22 abstract "We describe RDF123, a highly flexible open-source tool for translating spreadsheet data to RDF. Existing spreadsheet-to-rdf tools typically map only to star-shaped RDF graphs, i.e. each spreadsheet row is an instance, with each column representing a property. RDF123, on the other hand, allows users to define mappings to arbitrary graphs, thus allowing much richer spreadsheet semantics to be expressed. Further, each row in the spreadsheet can be mapped with a fairly different RDF scheme. Two interfaces are available. The first is a graphical application that allows users to create their mapping in an intuitive manner. The second is a Web service that takes as input a URL to a Google spreadsheet or CSV file and an RDF123 map file, and provides RDF as output.".
• 224 abstract "The process of authoring ontologies requires the active involvement of domain experts who should lead the process, as well as providing the relevant conceptual knowledge. However, most domain experts lack knowledge modelling skills and find it hard to follow logical notations in OWL. This paper presents ROO, a tool that facilitates domain experts' definition of ontologies in OWL by allowing them to author the ontology in a controlled natural language called Rabbit. ROO guides users through the ontology construction process by following a methodology geared towards domain experts’ involvement in ontology authoring, and exploiting intelligent user interfaces techniques. An evaluation study has been conducted comparing ROO against another popular ontology authoring tool. Participants were asked to create ontologies based on hydrology and environment modelling scenarios related to real tasks at the mapping agency of Great Britain. The study is discussed, focusing on the usability and usefulness of the tool, and the quality of the resultant ontologies.".
• 229 abstract "Finding mappings between compatible ontologies is an important but difficult open problem. Instance-based methods for solving this problem have the advantage of focusing on the most active parts of the ontologies and reflect concept semantics as they are used in the real world. However such methods have not at present been widely investigated in ontology mapping, compared to linguistic and structural techniques. In this paper we approach the mapping problem as a classification problem based on the similarity between instances of concepts. We evaluate the resulting classifier on three different real-world data sets.".
• 232 abstract "The emergence of web based systems in which users can annotate items, raises the question of the semantic interoperability between vocabularies originating from collaborative annotation processes, often called folksonomies, and keywords assigned in a more traditional way. If collections are annotated according to two systems, e.g. with tags and keywords, the annotated data can be used for instanced based mapping between the vocabularies. The basis for this kind of matching is an appropriate similarity measure between concepts, based on their distribution as annotations. In this paper we propose a new similarity measure that can take advantage of some special properties of user generated metadata. We have evaluated this measure with a set of articles from Wikipedia which are classified according to the topic structure of Wikipedia and that are annotated by users of the bookmarking service del.icio.us as well. The results using the new measure are significantly better than those obtained using standard similarity measures proposed for this task in the literature. We argue that the measure also has benefits for instance based mapping of more traditionally developed vocabularies. Finally, this method opens possibilities for instance based mapping of annotation data in the absence of a collection described according to both systems.".
• 237 abstract "We present a technique for answering queries over RDF data through an evolutionary search algorithm, using fingerprinting and bloomfilters for rapid approximate evaluation of generated solutions. Our evolutionary approach has several advantages compared to traditional database-style query answering. First, the result quality increases monotonically and converges with each evolution, offering ``anytime'' behaviour with arbitrary trade-off between computation time and query results; in addition, the level of approximation can be tuned by varying the size of the bloomfilters. Secondly, through bloomfilter compression we can fit large graphs in main memory, reducing the need for disk I/O during query evaluation. Finally, since the individuals evolve independently, parallel execution is straightforward. We present an initial prototype that evaluates basic SPARQL queries over arbitrary RDF graphs and show initial results over large datasets.".
• 246 abstract "A justification for an entailment in an OWL ontology is a minimal subset of the ontology that is sufficient for that entailment to hold. Since justifications respect the syntactic form of axioms in an ontology, they are usually neither syntactically nor semantically minimal. This paper presents two new subclasses of justifications - laconic justications and precise justications. Laconic justications only consist of axioms that do not contain any redundant parts. Precise justications can be derived from laconic justications and are characterised by the fact that they consist of flat, small axioms, which facilitate the generation of semantically minimal repairs. Formal denitions for both types of justication are presented. In contrast to previous work in this area, these definitions make it clear as to what exactly parts of axioms are. In order to demonstrate the practicability of computing laconic, and hence precise justications, an algorithm is provided and results from an empirical evaluation carried out on several published ontologies are presented. The evaluation showed that laconic/precise justications can be computed in a reasonable time for entailments in a range of ontologies that vary in size and complexity. It was found that in half of the ontologies sampled there were entailments that had more laconic/precise justications than regular justications. More surprisingly it was observed that for some ontologies there were fewer laconic/precise justications than regular justications.".
• 251 abstract "Ontologies are becoming so large in their coverage that no single person or a small group of people can develop them effectively and ontology development becomes a community-based enterprise. In this paper, we discuss requirements for supporting collaborative ontology development and present Collaborative Protege-—a tool that supports many of these requirements, such as discussions integrated with ontology-editing process, chats, and annotations of changes and ontology components. We have evaluated Collaborative Protege in the context of ontology development in an ongoing large-scale biomedical project that actively uses ontologies: the ATHENA-DSS project at the VA Palo Alto Healthcare System. Users have found the new tool effective as an environment for carrying out discussions and for recording references for the information sources and design rationale.".
• 259 abstract "It has been largely recognized that navigational capabilities are fundamental for graph databases query languages. However, although RDF is a directed labeled graph data format, the W3C Recommendation query language for RDF, SPARQL, only provides limited navigational functionalities. This has motivated several authors to propose extensions of SPARQL, or alternative query languages, that offer functionalities for navigating RDF data. In particular, we argued in [6] that nested regular expressions are appropriate to overcome this limitation, and we proposed a query language called nSPARQL that extends SPARQL with this type of expressions. In this paper, we continue with the investigation of nSPARQL. First, we show that nested regular expressions can be evaluated efficiently; if the appropriate data structure is used to store RDF graphs, then the evaluation of a nested regular expression E over an RDF graph G can be computed in time O(|G|*|E|). Second, as RDF graphs may contain RDFS vocabulary, we study how the navigational capabilities of nSPARQL can be used to evaluate queries according to the predefined semantics of RDFS. Evaluating queries which involve the RDFS vocabulary is challenging, and there is not yet consensus in the Semantic Web community on how to define a query language for RDFS. In this respect, we show that nSPARQL is expressive enough to answer SPARQL queries involving RDFS vocabulary by directly traversing the input RDF graphs. Moreover, we also prove that nesting is necessary to obtain this result. Namely, we show that, in general, regular expressions alone cannot be used to obtain the answer of a SPARQL query involving RDFS vocabulary.".
• 260 abstract "Conjunctive query answering over OWL-DL ontologies is intractable in the worst case, but we present novel techniques which allow for efficient querying of large expressive knowledge bases in secondary storage. In particular, we show that we can effectively answer conjunctive queries without building a complete completion forest for a large ABox (unlike state of the art tableau reasoners). Instead we rely on the completion forest of a dramatically reduced summary of the Abox. We demonstrate the effectiveness of this approach in Aboxes with up to 45 million assertions.".
• 262 abstract "This paper studies the expressive power of SPARQL. The main result is that SPARQL and non-recursive safe Datalog with negation have equivalent expressive power, and hence, by classical results, SPARQL is equivalent from an expressive point of view to relational Algebra. We present explicit generic rules of the transformations in both directions. Among other findings of the paper are the proof that negation can be simulated in SPARQL, that non-safe filters are superfluous, and that current SPARQL W3C semantics can be simplified to a standard compositional one.".
• 268 abstract "Efficient and scalable discovery mechanisms are critical for enabling service-oriented architectures on the Semantic Web. The majority of currently existing approaches focuses on centralized architectures, and deals with efficiency typically by pre-computing and storing the results of the semantic matcher for all possible query concepts. Such approaches, however, fail to scale with respect to the number of service advertisements and the size of the ontologies involved. On the other hand, this paper presents an efficient and scalable index-based method for Semantic Web service discovery that allows for fast selection of services at query time and is suitable for both centralized and P2P environments. We employ a novel encoding of the services descriptions, allowing the match between a request and an advertisement to be evaluated in constant time, and we index these representations to prune the search space, reducing the number of comparisons required. Given a desired ranking function, the search algorithm can retrieve the top-k matches progressively, i.e., better matches are computed and returned first, thereby further reducing the search engine's response time. We show also how this search can be performed efficiently in a suitable structured P2P overlay network. The benefits of the proposed method are demonstrated through experimental evaluation on both real and synthetic data.".
• 270 abstract "In this paper, we propose a general operator for revising terminologies in description logic-based ontologies. Our revision operator is based on a reformulation of the kernel contraction operator in belief revision. We first define our revision operator for terminologies in terms of MIPS (minimal incoherence-preserving sub-terminologies), and we show that it satisfies some desirable logical properties. Second, two algorithms are developed to instantiate the revision operator. Since these two algorithms are computationally too hard in general, we propose a third algorithm as a more efficient alternative. We implement the algorithms and provide evaluation results on their efficiency and effectiveness.".
• 273 abstract "We propose a novel method for reasoning in the description logic SHIQ. After a satisfiability preserving transformation from SHIQ to the description logic ALCIb, the obtained ALCIb Tbox T is converted into an ordered binary decision diagram (OBDD) which represents a canonical model for T. This OBDD is turned into a disjunctive datalog program that can be used for Abox reasoning. The algorithm is worst-case optimal w.r.t. data complexity, and admits easy extensions with DL-safe rules and ground conjunctive queries.".
• 322 abstract "The Web Ontology Language (OWL) provides a modelling paradigm that is especially well suited for developing models of large, structurally complex domains such as those found in Health Care and the Life Sciences. OWL's declarative nature combined with powerful reasoning tools has effectively supported the development of very large and complex anatomy, disease, and clinical ontologies. OWL, however, is not a programming language, so using these models in applications necessitates both a technical means of integrating OWL models with programs and considerable methodological sophistication in knowing how to integrate them. In this paper, we present an analytical framework for evaluating various OWL-Java combination approaches. We have developed a software framework for what we call hybrid modelling, that is, building models in which part of the model exists and is developed directly in Java and part of the model exists and is developed directly in OWL. We analyse the advantages and disadvantages of hybrid modelling both in comparison to other approaches and by means of a case study of a large medical records system.".
• 328 abstract "A family of parametric language-independent kernel functions defined for individuals in OWL ontologies is presented. These functions enable the exploitation of statistical learning for various ontology mining tasks. Namely, the novel kernel functions are integrated with a support vector machine for inducing simple mathematical models that can used for performing classification through an alternative mode w.r.t. logical reasoning. Besides we also present a method for adapting the kernel to the knowledge base through stochastic optimization. An inductive approach based on machine learning may be useful especially to cope with the inherent incompleteness of the knowledge bases. The system implementing the whole framework has been tested in some experiments on query answering with real ontologies drawn from standard repositories.".
• 334 abstract "Human-defined concepts are fundamental building-blocks in constructing knowledge bases such as ontologies. Statistical learning techniques provide an alternative automated approach to concept definition, driven by data rather than prior knowledge. In this paper we propose a probabilistic modeling framework that combines both human-defined concepts and data-driven topics in a principled manner. The methodology we propose uses statistical topic models (also known as latent Dirichlet allocation models). We demonstrate the utility of this general framework in two ways. We first illustrate how the methodology can be used to automatically tag Web pages with concepts from a known set of concepts without any need for labeled documents. We then perform a series of experiments that quantify how combining human-defined semantic knowledge with data-driven techniques leads to better language models than can be obtained with either alone.".
• 341 abstract "This paper describes the first steps towards developing a methodology for testing and evaluating the performance of reasoners for the probabilistic description logic P-SHIQ(D). Since P-SHIQ(D) is a relatively new formalism for handling uncertainty in DL knowledge bases, no such methodology has been proposed so far. Moreover there are no sufficiently large probabilistic ontologies to be used as test suites. In addition, since the reasoning services in P-SHIQ(D) are mostly query oriented, there is no single problem (like classification or realization in classical DL) that could be an obvious candidate for benchmarking. All these issues make it hard to evaluate the performance of reasoners, reveal the complexity bottlenecks and assess the effect of optimization strategies. This paper aims at alleviating these important problems by making the following contributions: First, it describes a probabilistic ontology that has been developed for the real-life domain of breast cancer and which poses significant challenges for the state-of-art P-SHIQ(D) reasoners. Second, it explains a systematic approach to generating a series of probabilistic reasoning problems that allow to evaluate the reasoning performance and shed light on what makes reasoning in P-SHIQ(D) hard in practice. Finally, the paper explains the optimization strategy that helps to overcome some of the difficulties of reasoning revealed during the experiments. The impact of the strategy is also demonstrated using the developed evaluation methodology.".
• 342 abstract "An approach to improve an RCC-derived geospatial approximation is presented which makes use of OWL class inclusion axioms. The algorithm used to control the approximation combines hypothesis testing with consistency checking provided by a knowledge representation system based on description logics. Propositions about the consistency of the refined ABox w.r.t. the associated TBox when compared to baseline ABox and TBox are made. Formal proves of the divergent consistency results when checking either of both are provided. The application of the approach to a geospatial setting results in a roughly tenfold improved approximation when using the refined ABox and TBox. Ways to further improve the approximation and to automate the detection of falsely calculated relations are discussed.".
• 347 abstract "We introduce ELP as a decidable fragment of the Semantic Web Rule Language (SWRL) that admits reasoning in polynomial time. ELP is based on the tractable description logic EL++, and encompasses an extended notion of the recently proposed DL rules for that logic. Thus ELP extends EL++ with a number of features introduced by the forthcoming OWL 2, such as disjoint roles, local reflexivity, certain range restrictions, and the universal role. We present a reasoning algorithm based on a translation of ELP to Datalog, and this translation also enables the seamless integration of DL-safe rules into ELP. While reasoning with DL-safe rules as such is already highly intractable, we show that DL-safe rules based on the Description Logic Programming (DLP) fragment of OWL 2 can be admitted in ELP without losing tractability.".
• 360 abstract "We present Redgraph, a generic virtual reality visualization program for Semantic Web data capable of handling large data-sets, which we demonstrate on social network data from the U.S. Patent Trade Office. We develop a Semantic Web vocabulary of virtual reality terms compatible with GraphXML to map graph visualization into the Semantic Web itself. Our approach in visualizing Semantic Web data takes advantage of user-interaction in an immersive environment to bypass a number of difficult issues in the 3-dimensional graph visualization layout problem by relying on the user themselves to interactively extrude the nodes and links of a 2-dimensional network into the third dimension. When users touch nodes in the virtual reality environment, they retrieve data formatted according to the data's schema or ontology. We applied Redgraph to social network data constructed from patents, inventors, and institutions from the United States Patent and Trademark Office in order to explore networks of innovation in computing. Using this data-set, we present the results of a user study comparing extrusion (3-D) vs. no-extrusion (2-D). The use of a 3-D interface showed that subjects led to significant improvement on answering of fine-grained questions about the data-set, but no significant difference was found broad questions about the overall structure of the data were asked. Furthermore, inference can be used to improve the visualization, as demonstrated with a data-set of biotechnology patents and researchers.".
• 60 abstract "Currently proposed SemanticWeb Services technologies allow the semantic description of Web services so that software agents are able to discover, invoke, compose and monitor these services with a high degree of automation. This is achieved by marking up services with ontology-based semantic descriptions. The OWL Services (OWL-S) ontology is an upper ontology in OWL language, providing essential vocabularies to semantically describe Web services. Currently OWL-S services can only be developed independently, if one service is unavailable then finding a suitable alternative would require an expensive and difficult global search/match. It is desirable to have a new OWL-S construct that can systematically support substitution tracing as well as incremental development and reuse for services. Introducing inheritance relationship (IR) into OWLS is a natural solution. However, OWL-S, as well as most of the other currently discussed formalisms for Semantic Web Services such as WSMO or SAWSDL, has yet to define a concrete and self-contained mechanism of establishing inheritance relationships among services, which we believe is very important for the automated creation and discovery of Web services as well as human organization of services into a taxonomy-like structure. In this paper, we extend OWL-S with the possibility to define and maintain inheritance relationships between services. Through the definition of an additional “inheritance profile”, inheritance relationships can be stated and reasoned about. Two types of IRs are allowed to grant service developers the choice to respect the “contract” between services or not. The proposed inheritance framework has also been implemented and the prototype will be discussed as well.".
• 63 abstract "More and more ontologies have been published and used widely on the web such as FOAF, CYC and WordNet. In order to make good use of an ontology, especially a new and large scale ontology, we need methods to help under- stand it first. Identifying potentially important concepts and relations in an ontology is an intuitive but challeng- ing method. In this paper, inspired by the Stream of Con- sciousness theory, we first define six features for potential important concepts and relation from the ontological struc- tural point of view. Then a simple yet effective Concept- And-Relation-Ranking (CARRank) algorithm is proposed to simultaneously rank the importance of concepts and rela- tions. Different from the traditional ranking methods, the importance of concepts and the weights of relations reinforce one another in CARRank in an iterative manner. Such an iterative process is proved to be convergent both in princi- ple and by experiments. Our experimental results show that CARRank has a similar convergent speed as the PageRank- like algorithms, but a more reasonable ranking result.".
• 76 abstract "Re-using and combining multiple ontologies on the Web is bound to lead to inconsistencies between the combined vocabularies. Even many of the ontologies that are in use today turn out to be inconsistent once some of their implicit knowledge is made explicit. However, robust and efficient methods to deal with inconsistencies are lacking from current Semantic Web reasoning systems, which are typically based on classical logic. In earlier papers, we have proposed the use of syntactic relevance functions as a method for reasoning with inconsistent ontologies. In this paper, we extend that work to the use of semantic distances. We show how Google distances can be used to develop semantic relevance functions to reason with inconsistent ontologies. In essence we are using the implicit knowledge hidden in the Web for explicit reasoning purposes. We have implemented this approach as part of the PION reasoning system. We report on experiments with several realistic ontologies. The test results show that a mixed syntactic/semantic approach can significantly improve reasoning performance over the purely syntactic approach. Furthermore, our methods allow to trade-off computational cost for inferential completeness. Our experiment shows that we only have to give up a little quality to obtain a high performance gain.".
• 91 abstract "Controlled Language (CL) for Ontology Editing tools offer an attractive alternative for naive users wishing to create ontologies, but they are still required to spend time learning the correct syntactic structures and vocabulary in order to use the Controlled Language properly. This paper extends previous work (CLOnE) which uses standard NLP tools to process the language and manipulate an ontology. Here we also generate text in the CL from an existing ontology using template-based (or shallow) Natural Language Generation (NLG). The text generator and the CLOnE authoring process combine to form a RoundTrip Ontology Authoring environment: one can start with an existing imported ontology or one originally produced using CLOnE, (re)produce the Controlled Language, modify or edit the text as required and then turn the text back into the ontology in the CLOnE environment. Building on previous methodology we undertook an evaluation, comparing the RoundTrip Ontology Authoring process with a well-known ontology editor; where previous work required a CL reference manual with several examples in order to use the controlled language, the use of NLG reduces this learning curve for users and improves on existing results for basic ontology editing tasks.".
• 101 abstract "Currently a large number of Web sites are driven by Content Management Systems (CMS) which manage textual and multimedia content but also - inherently - carry valuable information about a site's structure and content model. Exposing this structured information to the Web of Data has so far required considerable expertise in RDF and OWL modelling and additional programming effort. In this paper we tackle one of the most popular CMS: Drupal. We enable site administrators to export their site content model and data to the Web of Data without requiring extensive knowledge on Semantic Web technologies. Our modules create RDFa annotations and -- optionally -- a SPARQL endpoint for any Drupal site out of the box. Likewise, we add the means to map the site data to existing ontologies on the Web with a search interface to find commonly used ontology terms. We also allow a Drupal site administrator to include existing RDF data from remote SPARQL endpoints on the Web in the site. When brought together, these features allow networked RDF Drupal sites that reuse and enrich Linked Data. We finally discuss the adoption of our modules and report on a use case in the biomedical field and the current status of its deployment.".
• 104 abstract "In this paper, we report on a technology-transfer effort on using the Semantic Web (SW) technologies, esp. ontology matching, for solving a real-life library problem: book subject indexing. Our purpose is to streamline one library's book description process by suggesting new subjects based on descriptions created by other institutions, even when the vocabularies used are different. The case at hand concerns the National Library of the Netherlands (KB) and the network of Dutch local public libraries. We present a prototype subject suggestion tool, which is directly connected to the KB production cataloguing environment. We also report on the results of a user study and evaluation to assess the feasibility of exploiting state-of-the art techniques in such a real-life application. Our prototype demonstrates that SW components can be seamlessly plugged into the KB production environment, which potentially brings a higher level of flexibility and openness to networked Cultural Heritage (CH) institutions. Technical hurdles can be tackled and the suggested subjects are often relevant, opening up exciting new perspectives on the daily work of the KB. However, the general performance level should be made higher to warrant seamless embedding in the production environment—notably by considering more contextual metadata for the suggestion process.".
• 141 abstract "Military training and testing events are highly complex affairs, potentially involving dozens of legacy systems that need to interoperate in a meaningful way. There are superficial interoperability concerns (such as two systems not sharing the same messaging formats), but also substantive problems such as different systems not sharing the same understanding of the terrain, positions of entities, and so forth. We describe our approach to facilitating such events: describe the systems and requirements in great detail using ontologies, and use automated reasoning to automatically find and help resolve problems. The complexity of our problem took us to the limits of what one can do with OWL, and we needed to introduce some innovative techniques of using and extending it. We describe our novel ways of using SWRL and discuss its limitations as well as extensions to it that we found necessary or desirable. Another innovation is our representation of hierarchical tasks in OWL, and an engine that reasons about them. Our task ontology has proved to be a very flexible and expressive framework to describe requirements on resources and their capabilities in order to achieve some purpose.".
• 143 abstract "A common vocabulary is vital to smooth business operation, yet codifying and maintaining an enterprise vocabulary is an arduous, manual task. We describe a process to automatically extract a domain specific vocabulary (terms and types) from unstructured data in the enterprise guided by term definitions in Linked Open Data (LOD). We validate our techniques by applying them to the IT (Information Technology) domain, taking 58 Gartner analyst reports and using two specific LOD sources -- DBpedia and Freebase.".
• 156 abstract "The objective of the Market Blended Insight (MBI) project is to develop web based techniques to improve the performance of UK Business to Business (B2B) marketing activities. The analysis of company value chains is a fundamental task within MBI because it is an important model for understanding the market place and the company interactions within it. The project has aggregated rich data profiles of 3.7 million companies that form the active UK business community. The profiles are augmented by Web extractions from heterogeneous sources to provide unparalleled business insight. Advances by the Semantic Web in knowledge representation and logic reasoning allow flexible integration of data from heterogeneous sources, transformation between different representations and reasoning about their meaning. The MBI project has identified that the market insight and analysis interests of different types of users are difficult to maintain using a single domain ontology. Therefore, the project has developed a technique to undertake a plurality of analyses of value chains by deploying a distributed multi-view ontology to capture different user views over the classification of companies and their various relationships.".
• 157 abstract "Taking customer data as an example, the paper presents an approach to enhance the management of enterprise data by using Semantic Web technologies. Customer data is the most important kind of core business entity a company uses repeatedly across many business processes and systems, and customer data management (CDM) is becoming critical for enterprises because it keeps a single, complete and accurate record of customers across the enterprise. Existing CDM systems focus on integrating customer data from all customer-facing channels and front and back office systems through multiple interfaces, as well as publishing customer data to different applications. To make the effective use of the CDM system, this paper investigates semantic query and analysis over the integrated and centralized customer data, enabling automatic classification and relationship discovery. We have implemented these features over IBM Websphere Customer Center, and shown the prototype to our clients. We believe that our study and experiences are valuable for both Semantic Web community and data management community.".
• 170 abstract "One of the main software engineers’ competencies, solving software problems, is most effectively acquired through an active examination of learning resources and work on real-world examples in small development teams. This obviously indicates a need for an integration of several existing learning tools and systems in a common collaborative learning environment, as well as advanced educational services that provide students with right in time advice about learning resources and possible collaboration partners. In this paper, we present how we developed and applied a common ontological foundation for the integration of different existing learning tools and systems in a common learning environment called DEPTHS (Design Patterns Teaching Help System). In addition, we present a set of educational services that leverages semantic rich representation of learning resources and students’ interaction data to recom-mend resource relevant for students’ current learning context.".
• 171 abstract "The increase of personal digital cameras with video functionality and video-enabled camera phones has increased the amount of user-generated videos on the Web. People are spending more and more time viewing online videos as a major source of entertainment and “infotainment”. Social websites allow users to assign shared free-form tags to user-generated multimedia resources, thus generating annotations for objects with a minimum amount of effort. Tagging allows communities to organize their multimedia items into browseable sets, but these tags may be poorly chosen and related tags may be omitted. Current techniques to retrieve, integrate and present this media to users are deficient and could do with improvement. In this paper we describe a framework for semantic enrichment, ranking and integration of web video tags using Semantic Web technologies. Semantic enrichment of folksonomies can bridge the gap between the uncontrolled and flat structures typically found in user-generated content and structures provided by the Semantic Web. The enhancement of tag spaces with semantics has been accomplished through two major tasks: (1) a tag space expansion and ranking step; and (2) through concept matching and integration with the Linked Data cloud. We have explored social, temporal and spatial contexts to enrich and extend the existing tag space. The resulting semantic tag space is modelled via a local graph based on co-occurrence distances for ranking. A ranked tag list is mapped and integrated with the Linked Data cloud through the DBpedia resource repository. Multi-dimensional context filtering for tag expansion means that tag ranking is much easier and it provides less ambiguous tag to concept matching.".
• 183 abstract "Internet business-to-business transactions present great challenges in merging information from different sources. In this paper we describe a project to integrate four representative commercial classification systems with the Federal Cataloging System (FCS). The FCS is used by the US Defense Logistics Agency to name, describe and classify all items under inventory control by the DoD. Our approach uses the ECCMA Open Technical Dictionary (eOTD) as a common vocabulary to accommodate all different classifications. We create a semantic bridging ontology between each classification and the eOTD to describe their logical relationships in OWL DL. The essential idea is that since each classification has formal definitions in a common vocabulary, we can use subsumption to automatically integrate them, thus mitigating the need for pairwise mappings. Furthermore our system provides an interactive interface to let users choose and browse the results and more importantly it can translate catalogs that commit to these classifications using compiled mapping results.".
• 200 abstract "We investigated the use of a hybrid search and query for locating enterprise data relevant to a requesting party’s legal case (e-discovery identification). We extended the query capabilities of SPARQL with search capabilities to provide integrated access to structured, semi-structured and unstructured data sources. Every data source in the enterprise is potentially within the scope of e-discovery identification. So we use some common enterprise structured data sources that provide product and organizational information to guide the search and restrict it to a manageable scale. We use hybrid search and query to conduct a rich high-level search, which identifies the key people and products to coarsely locate relevant data-sources. Furthermore the product and organizational data sources are also used to increase recall which is a key requirement for e-discovery Identification.".
• 203 abstract "In this paper we present a method and an implementation for creating and processing semantic events from interaction with Web pages which opens possibilities to build event-driven applications for the (Semantic) Web. Events, simple or complex, are models for things that happen e.g., when a user interacts with a Web page. Events are consumed in some meaningful way e.g., for monitoring reasons or to trigger actions such as responses. In order for receiving parties to understand events e.g., comprehend what has led to an event, we propose a general event schema using RDFS. In this schema we cover the composition of complex events and event-to-event relationships. These events can then be used to route semantic information about an occurrence to different recipients helping in making the Semantic Web active. Additionally, we present an architecture for detecting and composing events in Web clients. For the contents of events we show a way of how they are enriched with semantic information about the context in which they occurred. The paper is presented in conjunction with the use case of Semantic Advertising, which extends traditional clickstream analysis by introducing semantic short-term profiling, enabling discovery of the current interest of a Web user and therefore supporting advertisement providers in responding with more relevant advertisements.".
• 206 abstract "The exponential growth of the World Wide Web in the last decade brought an explosion in the information space, which has important consequences also in the area of scientific research. Finding relevant work in a particular field and exploring the links between publications is currently a cumbersome task. Similarly, on the desktop, managing the publications acquired over time can represent a real challenge. Extracting semantic metadata, exploring the linked data cloud and using the semantic desktop for managing personal information represent, in part, solutions for different aspects of the above mentioned issues. In this paper, we propose an innovative approach for bridging these three directions with the overall goal of alleviating the information overload problem burdening early stage researchers. Our application combines harmoniously document engineering-oriented automatic metadata extraction with information expansion and visualization based on linked data, while the resulting documents can be seamlessly integrated into the semantic desktop.".
• 207 abstract "In order to employ the Web as a medium for data and information integration, comprehensive datasets and vocabularies are required as they enable the disambiguation and alignment of other data and information. Many real-life information integration and aggregation tasks are impossible without comprehensive background knowledge related to spatial features of the ways, structures and landscapes surrounding us. In this paper we contribute to the generation of a spatial dimension for the Data Web by elaborating on how the collaboratively collected OpenStreetMap data can be transformed and represented adhering to the RDF data model. We describe how this data can be interlinked with other spatial data sets, how it can be made accessible for machines according to the linked data paradigm and for humans by means of a faceted geo-data browser.".
• 208 abstract "As the amount of available RDF data continues to increase steadily, there is growing interest in developing efficient methods for analyzing such data. While recent efforts have focused on developing efficient methods for traditional data processing, analytical processing which typically involves more complex queries has received much less attention. The use of cost effective parallelization techniques such as Google’s Map-Reduce offer significant promise for achieving Web scale analytics. However, currently available implementations are designed for simple data processing on structured data. In this paper, we present a language, RAPID, for scalable ad-hoc analytical processing of RDF data on Map-Reduce frameworks. It builds on Yahoo’s Pig Latin by introducing primitives based on a specialized join operator, the MD-join, for expressing analytical tasks in a manner that is more amenable to parallel processing, as well as primitives for coping with semi-structured nature of RDF data. Experimental evaluation results demonstrate significant performance improvements for analytical processing of RDF data over existing Map-Reduce based techniques".
• 213 abstract "Social interactions are one of the key factors to the success of conferences and similar community gatherings. This paper describes a novel application that integrates data from the semantic web, online social networks, and a real-world contact sensing platform. This application was successfully deployed at ESWC09, and actively used by 139 people. Personal profiles of the participants were automatically generated using several Web~2.0 systems and semantic academic data sources, and integrated in real-time with face-to-face contact networks derived from wearable sensors. Integration of all these heterogeneous data layers made it possible to offer various services to conference attendees to enhance their social experience such as visualisation of contact data, and a site to explore and connect with other participants. This paper describes the architecture of the application, the services we provided, and the results we achieved in this deployment.".
• 101 abstract "Application integration can be carried out on three different levels: the data source level, the business logic level, and the user interface level. With ontologies-based integration on the data source level dating back to the 1990s and semantic web services for integrating on the business logic level coming of age, it is time for the next logical step: employing ontologies for integration on the user interface level. Such an approach will improve both the development times and the usability of integrated applications. In this poster, we present an approach employing ontologies for integrating applications on the user interface level.".
• 107 abstract "In this paper, we present an approach that exploits semantic web technologies to categorize specialized text and to create hierarchical facets representing the document content. For this purpose, domain knowledge represented by a thesaurus with relevant, domain-specific terms is used to identify relevant terms. Based on dependency information between single terms provided by the thesaurus (hypernomy, hyponymy), we create hierarchical facets representing the content of the text. The algorithm is applied to a collection of service messages and shows promising results in text categorization.".
• 108 abstract "Publishing and consuming content on the Web of Data often requires considerable expertise in the underlying technologies, as the expected services to achieve this are either not packaged in a simple and accessible manner, or are simply lacking. In this poster, we address selected issues by briefly introducing the following essential Web of Data services designed to lower the entry-barrier for Web developers: (i) a multi-ping service, (ii) a meta search service, and (iii) a universal discovery service.".
• 109 abstract "LMI is a not-for-profit research organization committed to helping government leaders and managers reach decisions that make a difference on issues of national importance. Climate change will be one of the defining issues of this century. It has moved from the province of specialists in environmental issues to one of concern for all government leaders. The International Panel on Climate Change (IPCC), the U.S. Global Change Research Program, and individual U.S. agencies have produced important studies of climate change. However, the IPCC Fourth Assessment Report (AR4) alone is over 2600 pages. Within these pages, LMI identified 2693 findings that include specific defined levels of uncertainty. The findings from the IPCC have been so thoroughly demonstrated by the scientific method that it would be a failure of responsibility to ignore them. They form the basis for the LMI Climate Change Knowledge Engine (LMI-CliCKE™) and A Federal Leader’s Guide to Climate Change – a LMI published book written to assist leaders of federal agencies in addressing the challenges associated with climate change. Thorough analysis of the 2693 findings led LMI to develop a semantically driven, wiki-based web site that allows users to explore, analyze, evaluate, and compare scientific findings related to climate change. The LMI Climate Change Knowledge Engine (LMI-CliCKE™) gives full text and categorical details of the findings and relationships among them. As an initial prototype the LMI climate team has selected and categorized all findings from the AR4.".
• 113 abstract "All About That (AAT) is a URI Profiling tool which allows users to monitor and preserve Linked Data in which they are interested. Its design is based upon the principle of adapting ideas from hypermedia link integrity in order to apply them to the Semantic Web. As the Linked Data Web expands it will become increasingly important to maintain links such that the data remains useful and therefore this tool is presented as a step towards providing this maintenance capability.".
• 117 abstract "As the Linked Data initiatives and Web of Data become more widespread, sites that process and re-present the published data are growing in size and number. One challenge is to ensure that such sites do not themselves fall into the trap of failing to publish their new knowledge in a readily available manner. Not only should the work of such sites be re-published for Linked Data users, but it should also be accessible to site builders who have not yet embraced the Semantic Web. This paper presents the work that has been done with the RKBExplorer system to support this task, and describes examples of how it is used.".
• 118 abstract "We present iSMART, a system for intelligent Semantic MedicAl Record reTrival. Health Level 7 Clinical Document Architecture (CDA)[4], a standard based on XML, is well recognized for the representation and exchange of medical records. In CDAs, medical ontologies/terminologies, e.g. SNOMED CT[2], are used to specify the semantic meaning of clinical statements. To better use the structure and semantic information in CDAs for a more effective search, we propose and implement the iSMART system. Firstly, we design and implement an XML-to-RDF convertor to extract RDF statements from medical records using declarative mapping. Then, we design a reasoner to infer additional information by integrating the knowledge from the domain ontologies based on the extracted RDF statements. Finally, we index the inferred set of RDF statements and provide the semantic search on them. A demonstration video is available online[1].".
• 119 abstract "LifeLogOn is a system that enables users to easily and rapidly convert heterogeneous relational log data into instance-level integrated log ontology without requiring understanding any ontology languages. It also enables visualizing the created log ontology and allows users to navigate entities and events in the ontology by following their semantic relationships. This demo shows that integration of logs from many different sources can be practical starting point of realizing life logging which can support users’ memory and future intelligent services.".
• 120 abstract "The AgreementMaker system for ontology matching includes an extensible architecture, which facilitates the integration and performance tuning of a variety of matching methods, an evaluation mechanism, which can make use of a reference matching or rely solely on quality measures, and a multi-purpose user interface, which drives both the matching methods and the evaluation strategies. Our demo focuses on the tight integration of matching methods and evaluation strategies, a unique feature of our system.".
• 121 abstract "The advent of technologies in information retrieval driven by users’ requests calls for an effort to conceive and develop semantic-based applications. In recent years the semantic web gave place for a new generation of search query engines that rely on the semantic of the documents expressed by metadata. In this paper we present a knowledge-based approach to visualizing and navigating through conference video-recordings. This approach is based on a conference ontology that models the information conveyed within a conference life cycle.".
• 122 abstract "Like web services, semantically-operated services can be assembled to construct a new composite service. For this, we designed the semantic broker that searches semantic services matched with given conditions, assembles them to dynamically generate pipelines of semantic services, and execute the pipelines. By executing the resulting pipelines, the user can select one which he/she really intended. In this way, our system can help the user who wants to design new semantically-operated services by mashing up the existing semantically-operated services.".
• 124 abstract "In this work, we describe our approach on how to deal with tag ambiguity in tagging systems and how to enable a sense aware or semantic search. The sense aware search is realized by means of a Sense Repository which returns for given terms a list of potential senses. This list is then presented to the user of the cross-folksonomy search engine MyTag so that he can explicitly select the sense he wants to search for. The search results are then ranked according to this sense so that relevant resources appear higher in the result list.".
• 125 abstract "Ontologies play a central role for the formal representation of knowledge on the Semantic Web. A major challenge in collaborative ontology construction is to handle inconsistencies caused by changes to the ontology. In this paper, we present our CoDR system which helps to diagnose and repair collaboratively constructed ontologies. CoDR integrates RaDON, an ontology diagnosis and repair tool, and Cicero, which provides discussion functionality for the ontology developers. CoDR is realized as a plugin for the NeOn Toolkit. It helps to use discussions held in Cicero as context information during repairing an ontology with RaDON. But it is also possible to use the diagnoses from RaDON during the discussions in Cicero.".
• 126 abstract "The exponential growth of the World Wide Web in the last decade, brought an explosion in the information space, which has important consequences also in the area of scientific research. Thus, finding relevant work in a particular field and exploring the links between publications is quite a cumbersome task. Similarly, on the desktop, managing the publications acquired over time can represent a real challenge. Extracting semantic metadata, exploring the linked data cloud and using the semantic desktop for managing personal information represent, in part, solutions for different aspects of the above mentioned issues. In this poster/demo, we show an innovative approach for bridging these three directions with the overall goal of alleviating the information overload problem burdening early stage researchers.".
• 129 abstract "STARS is an open source e-research tool that enables screen arts researchers to browse, annotate and replay moving image content in order to better understand its thematic links to those people and communities involved in all aspects of its creation. The STARS software was built using Semantic Web technologies to address the technical challenges of integrated searching, browsing and visualisation across curated core data and user-contributed annotations.".
• 130 abstract "We propose a new utility for Semantic Web called as Analogy Engine. Analogy engine employs an example based search approach for retrieving the most similar URIs for the given URI by comparing number of shared links. The Analogy engine is based on Analogy Space, which uses Singular Value Decomposition on matrix representation of a Semantic Network. However Analogy Space faces difficulty with networks having more than a few thousand nodes. We present our preliminary work on scaling Analogy Space by dividing the network into multiple communities, and creating separate Analogy Space for each community. We show that this procedure results in significant improvements and can be used for a large scale network such as the Semantic Web.".
• 133 abstract "WikiEarth (http://www.wikiearth.net) is a website designed for encouraging collaboration between researchers across the academic spectrum, and also serves as a test case to determine the limitations and benefits of using an ontological data structure to manage the input of natural science based data from around the world. Drawing upon Wikipedia's model of massive user collaboration, WikiEarth's motivation is to extend beyond this by formalizing the relationships between the data being entered. A semantic ontology is a natural candidate for data representation for three reasons: first, the hierarchical class structure of an OWL-Ontology helps avoid redundancy when developing simulations, as an operation can be applied to a class and all its subclasses; secondly, a framework like Jena helps eliminate human error and reduce the amount of data entry that needs to be performed; and finally, important restrictions regarding data entry are imposed by the ontological structure and Jena, as opposed to by a proprietary system developed for one specific application. Utilizing this infrastructure, a WikiEarth Climate Demonstration was successfully conceptualized, constructed, deployed and subsequently unveiled at the 2009 World Student Environmental Summit. The success of this application demonstrates that ontologies could be effectively purposed for a high-traffic production system.".
• 135 abstract "The diversity and heterogeneity of ocean observing systems obstructs the information flow needed to fully realise the benefits. SIOOS is a prototype for semantically-driven integration of ocean observation systems. SIOOS is built upon our Semantic Service Architecture platform, making rich use of complex ontologies and ontology-to-resource mappings to offer a flexible, semantically-driven integration environment. The SIOOS prototype draws on a federation of autonomous web and sensor observation services from the Integrated Ocean Observing System (IOOS). In this demonstration, we will use typical information management scenarios drawn from the ocean observation community to highlight major features of the SIOOS and show how these features address some of the challenges faced by the IOOS community.".
• 136 abstract "In this demo paper we describe SPoX, a tool that allows to define the behaviour of Skype based on reactive Semantic Web policies. SPoX (Skype Policy Extension) enables users to define policies stating, for example, who is allowed to call and whose chat messages show up. Moreover, SPoX reacts to arbitrary events in Skype's Social Network as well, such as on-line status changes of users or the birthday of a friend. The decisions about how SPoX reacts are defined by means of Semantic Web policies that do not only consider the context of the user (such as time or on-line status) but include Social Semantic Web data into the policy reasoning process. By this means, users can state that, for instance, only people defined as friends in their FOAF profile, only friends on Twitter, or even only people they wrote a paper with are allowed to call. Further, SPoX exploits Semantic Web techniques for advanced negotiations by means of exchanging policies over the Skype application channel. This procedure allows two clients to negotiate trust based on their SPoX policies before a connection - for example a Skype call - is established.".
• 137 abstract "We propose a diagrammatic logic that is suitable for specifying ontologies. We provide a specification of a simple ontology and include examples to show how to place constraints on ontology specifications and define queries. The framework also allows the depiction of instances, multiple ontologies to be related, and reasoning about ontologies.".
• 138 abstract "Recent work in explanation of entailments in ontologies has focused on justifications and their variants. While in many cases, just presenting the justification is sufficient for user understanding, and in all cases justifications are much better than nothing, we have empirically identified cases where understanding how a justification supports an entailment is inordinately difficult. Indeed there are naturally occurring justifications that people, with varying expertise in OWL, cannot understand. To address this problem, we have developed a novel conceptual framework for justification oriented proofs. Given a justification for an entailment in an ontology, intermediate inference steps, called lemmas, are automatically derived, that bridge the gap between the axioms in the justification and the entailment. The proof shows in a stepwise way how the lemmas and ultimately the entailment follow from the justification. At the heart of the framework is the notion of a ``complexity model'', which predicts how easy or difficult it is for a user to understand a justification, and is used for selecting the lemmas to insert into a proof. This poster and demo presents this framework backed by a prototype implementation.".
• 139 abstract "This paper describes the alpha Urban LarKC, one of the first Urban Computing applications built with Semantic Web technologies. It is based on the LarKC platform and makes use of the publicly available data sources on the Web which refer to interesting information about a urban environment (the city of Milano in Italy).".
• 140 abstract "Research profiling is a widely-adopted method to monitor research development and rank research performance. This paper describes a novel infrastructure to generate semantic-powered research profiling for research fields, organizations and individuals. It crawls related websites and news feeds, extracts research terms, research objects and relations from them and uses the proposed Research Ontology to model them into RDF triples to facilitate semantic queries and semantic mining on burst detection, hot topic detection, dynamics of research, and relation mining. The authors implement a research profiling experiment in Artificial Intelligence area to show the effectiveness of the research profiling based on semantic mining.".
• 143 abstract "Leadsto is a prototypical Semantic Portal for collaboratively describing statements of the form “x leads to y” (e.g. “accident leads to traffic jam”). Existing elements of statements (precedents, antecedents) can be linked with each other, and completely new elements can be created. Individual statements can be created and the set of stored statements further extended and developed collaboratively on the Web by humans; in addition, automated approaches for extracting further statements from any web page are employed. The constantly growing net-like structure can be searched and navigated. The major benefit of the system is to automatically discover and make available causal chains of the form “x leads to y “,” y leads to z “, etc. (as well as the reverse direction). In this way, not yet known facts as well as their provenance can be collaboratively discovered by the wisdom of a crowd.".
• 144 abstract "Mobile applications are of increasing interest for research and industry. The widespread use and improved capabilities of portable devices enable the deployment of sophisticated and powerful applications that provide the user with services at any time and location. When such applications are built on top of Linked Data, permanent network connectivity is required, which is often not available or expensive to establish. Hence we propose a framework that uses RDF-based context descriptions to selectively and proactively replicate data to mobile devices. These replicas can be used when no network connection can be established, thus making mobile applications and users more autonomous and stable.".
• 145 abstract "In this demo we show the current state of our client-side rule engine for the Web. The engine is an implementation for creating and processing semantic events from interaction with Web pages which opens possibilities to build event-driven applications for the (Semantic) Web. Events, simple or complex, are models for things that happen e.g., when a user interacts with a Web page. Events are consumed in some meaningful way e.g., for monitoring reasons or to trigger actions such as responses. In order for receiving parties to understand events, i.e. comprehend what has led to an event, we demonstrate a general event schema using RDFS.".
• 146 abstract "Spreadsheet tools are often used in business and private scenarios in order to collect and store data, and to explore and analyze these data by executing functions and aggregations. They allow users to incrementally compose calculations by filling cells with formulas that are evaluated against data in the sheet, whereas expressions can be nested via cell references. In this paper we present Tripcel, a tool that applies the spreadsheet concept to RDF. It allows users to formulate expressions over the contents of an RDF graph, to arrange these expressions in a grid, and to interactively inspect their evaluation results. Thus it can be used to perform analysis tasks over large data sets within an understandable and familiar interface.".

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