BibSonomy publications for /user/jaeschke/semanticFri Jan 20 10:30:56 CET 2012New York, NY, USAProceedings of the sixth international conference on Knowledge capture121--128Extracting relevant questions to an RDF dataset using formal concept analysis2011analysis concept fca formal ontology rdf semantic web With the rise of linked data, more and more semantically described information is being published online according to the principles and technologies of the Semantic Web (especially, RDF and SPARQL). The use of such standard technologies means that this data should be exploitable, integrable and reusable straight away. However, once a potentially interesting dataset has been discovered, significant efforts are currently required in order to understand its schema, its content, the way to query it and what it can answer. In this paper, we propose a method and a tool to automatically discover questions that can be answered by an RDF dataset. We use formal concept analysis to build a hierarchy of meaningful sets of entities from a dataset. These sets of entities represent answers, which common characteristics represent the clauses of the corresponding questions. This hierarchy can then be used as a querying interface, proposing questions of varying levels of granularity and specificity to the user. A major issue is however that thousands of questions can be included in this hierarchy. Based on an empirical analysis and using metrics inspired both from formal concept analysis and from ontology summarization, we devise an approach for identifying relevant questions to act as a starting point to the navigation in the question hierarchy.Mon Aug 22 22:58:12 CEST 2011Berlin/HeidelbergThe Semantic Web: Research and Applications10.1007/11762256_38514--529Lecture Notes in Computer ScienceSemantic Network Analysis of Ontologies401120062006 iccs_example l3s myown ontology semantic trias_example sna analysis network social A key argument for modeling knowledge in ontologies is the easy reuse and re-engineering of the knowledge. However, current ontology engineering tools provide only basic functionalities for analyzing ontologies. Since ontologies can be considered as graphs, graph analysis techniques are a suitable answer for this need. Graph analysis has been performed by sociologists for over 60 years, and resulted in the vivid research area of Social Network Analysis (SNA).While social network structures currently receive high attention in the Semantic Web community, there are only very few SNA applications, and virtually none for analyzing the structure of ontologies. We illustrate the benefits of applying SNA to ontologies and the Semantic Web, and discuss which research topics arise on the edge between the two areas. In particular, we discuss how different notions of centrality describe the core content and structure of an ontology. From the rather simple notion of degree centrality over betweenness centrality to the more complex eigenvector centrality, we illustrate the insights these measures provide on two ontologies, which are different in purpose, scope, and size. Wed Oct 13 11:56:13 CEST 2010Berlin / HeidelbergProceedings of the EKAW 2010 - Knowledge Engineering and Knowledge Management by the Masses; 11th October-15th October 2010 - Lisbon, Portugaloct135--149Lecture Notes in Artificial IntelligenceWeaving a Social Data Web with Semantic Pingback63172010blogging data pingback semantic social web In this paper we tackle some of the most pressing obstacles of the emerging Linked Data Web, namely the quality, timeliness and coherence as well as direct end user benefits. We present an approach for complementing the Linked Data Web with a social dimension by extending the well-known Pingback mechanism, which is a technological cornerstone of the blogosphere, towards a Semantic Pingback. It is based on the advertising of an RPC service for propagating typed RDF links between Data Web resources. Semantic Pingback is downwards compatible with conventional Pingback implementations, thus allowing to connect and interlink resources on the Social Web with resources on the Data Web. We demonstrate its usefulness by showcasing use cases of the Semantic Pingback implementations in the semantic wiki OntoWiki and the Linked Data interface for database-backed Web applications Triplify. Thu Aug 12 09:24:32 CEST 2010DCMI '08: Proceedings of the 2008 International Conference on Dublin Core and Metadata Applications128--137The state of the art in tag ontologies: a semantic model for tagging and folksonomies2008folksonomy ontology semantic tagging web There is a growing interest into how we represent and share tagging data in collaborative tagging systems. Conventional tags, meaning freely created tags that are not associated with a structured ontology, are not naturally suited for collaborative processes, due to linguistic and grammatical variations, as well as human typing errors. Additionally, tags reflect personal views of the world by individual users, and are not normalised for synonymy, morphology or any other mapping. Our view is that the conventional approach provides very limited semantic value for collaboration. Moreover, in cases where there is some semantic value, automatically sharing semantics via computer manipulations is extremely problematic. This paper explores these problems by discussing approaches for collaborative tagging activities at a semantic level, and presenting conceptual models for collaborative tagging activities and folksonomies. We present criteria for the comparison of existing tag ontologies and discuss their strengths and weaknesses in relation to these criteria.Thu Jan 14 18:31:02 CET 2010Dagstuhl, GermanySocial Web Communities08391Dagstuhl Seminar ProceedingsAnalyzing Tag Semantics Across Collaborative Tagging Systems20082008 collaborative dagstuhl myown semantic social tagging web The objective of our group was to exploit state-of-the-art Information Retrieval methods for finding associations and dependencies between tags, capturing and representing differences in tagging behavior and vocabulary of various folksonomies, with the overall aim to better understand the semantics of tags and the tagging process. Therefore we analyze the semantic content of tags in the Flickr and Delicious folksonomies. We find that: tag context similarity leads to meaningful results in Flickr, despite its narrow folksonomy character; the comparison of tags across Flickr and Delicious shows little semantic overlap, being tags in Flickr associated more to visual aspects rather than technological as it seems to be in Delicious; there are regions in the tag-tag space, provided with the cosine similarity metric, that are characterized by high density; the order of tags inside a post has a semantic relevance. Mon Nov 23 13:04:35 CET 2009BonnInformatik 2006 - Informatik für Menschenoct305--312Lecture Notes in InformaticsEmergent Semantics in BibSonomy9420062006 bibsonomy emergent folksonomy iccs_example l3s myown semantic trias_example Social bookmark tools are rapidly emerging on the Web. In such systems users are setting up lightweight conceptual structures called folksonomies. The reason for their immediate success is the fact that no specific skills are needed for participating. In this paper we specify a formal model for folksonomies, briefly describe our own system BibSonomy, which allows for sharing both bookmarks and publication references, and discuss first steps towards emergent semantics.Tue Nov 10 11:38:39 CET 2009Berlin/HeidelbergThe Semantic Web: Research and Applications486--499Lecture Notes in Computer ScienceCollaborative and Usage-Driven Evolution of Personal Ontologies.35322005ontology recommender semantic web Large information repositories as digital libraries, online shops, etc. rely on a taxonomy of the objects under consideration to structure the vast contents and facilitate browsing and searching (e.g., ACM topic classification for computer science literature, Amazon product taxonomy, etc.). As in heterogenous communities users typically will use different parts of such an ontology with varying intensity, customization and personalization of the ontologies is desirable. Of particular interest for supporting users during the personalization are collaborative filtering systems which can produce personal recommendations by computing the similarity between own preferences and the one of other people. In this paper we adapt a collaborative filtering recommender system to assist users in the management and evolution of their personal ontology by providing detailed suggestions of ontology changes. Such a system has been implemented in the context of Bibster, a peer-to-peer based personal bibliography management tool. Finally, we report on an experiment with the Bibster community that shows the performance improvements over non-personalized recommendations.Mon Nov 09 18:14:25 CET 2009New York, NY, USASIGIR '07: Proceedings of the 30th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval103--110Towards automatic extraction of event and place semantics from flickr tags2007emerging event extraction flickr folksonomy geo learning ol_tut2010 ontology place semantic web We describe an approach for extracting semantics of tags, unstructured text-labels assigned to resources on the Web, based on each tag's usage patterns. In particular, we focus on the problem of extracting place and event semantics for tags that are assigned to photos on Flickr, a popular photo sharing website that supports time and location (latitude/longitude) metadata. We analyze two methods inspired by well-known burst-analysis techniques and one novel method: Scale-structure Identification. We evaluate the methods on a subset of Flickr data, and show that our Scale-structure Identification method outperforms the existing techniques. The approach and methods described in this work can be used in other domains such as geo-annotated web pages, where text terms can be extracted and associated with usage patterns.Fri Oct 30 15:03:49 CET 2009submitted for publicationRecommending Semantic Annotations for Geographic Information2009annotation geo gis recommender semantic Tue Sep 15 09:54:26 CEST 2009Berlin/HeidelbergThe Semantic Web -- ISWC 2008615--631Lecture Notes in Computer ScienceSemantic Grounding of Tag Relatedness in Social Bookmarking Systems53182008folksonomy grounding semantic tagging 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. Eventhough most of these measures appear very natural, their design often seems to be rather ad hoc, and the underlying assumptionson the notion of similarity are not made explicit. A more systematic characterization and validation of tag similarity interms of formal representations of knowledge is still lacking. Here we address this issue and analyze several measures oftag similarity: Each measure is computed on data from the social bookmarking system del.icio.us and a semantic grounding isprovided by mapping pairs of similar tags in the folksonomy to pairs of synsets in Wordnet, where we use validated measuresof semantic distance to characterize the semantic relation between the mapped tags. This exposes important features of theinvestigated similarity measures and indicates which ones are better suited in the context of a given semantic application.Mon Aug 17 13:10:32 CEST 2009The Gnowsis -- Using Semantic Web Technologies to build a Semantic DesktopDiploma thesis2003desktop gnowsis semantic Wed Jun 17 15:45:23 CEST 2009Proceedings of I-Semantics' 07sep201--211The NEPOMUK Project - On the way to the Social Semantic Desktop20072007 desktop nepomuk semantic social This paper introduces the NEPOMUK project which aims to create a standard and reference implementation for the Social Semantic Desktop. We outline the requirements and functionalities that were identified for a useful Semantic Desktop system and present an architecture that fulfills these requirements which was acquired by incremental refinement of the architecture of existing Semantic Desktop prototypes. The NEPOMUK project is primarily motivated by three real-life industrial use-cases, we briefly outline these and the processes used to extract required functionalities from the people working in these areas today, and we present a selection of typical tasks where the Semantic Desktop could be of benefit.Wed Jun 17 11:39:11 CEST 2009Berlin/HeidelbergThe SemanticWeb - ISWC 2003sep738--753Lecture Notes in Computer ScienceHaystack: A Platform for Authoring End User Semantic Web Applications28702003desktop haystack semantic seminar2006 The Semantic Web promises to open innumerable opportunities for automation and information retrieval by standardizing the protocols for metadata exchange. However, just as the success of the World Wide Web can be attributed to the ease of use and ubiquity of Web browsers, we believe that the unfolding of the Semantic Web vision depends on users getting powerful but easy-to-use tools for managing their information. But unlike HTML, which can be easily edited in any text editor, RDF is more complicated to author and does not have an obvious presentation mechanism. Previous work has concentrated on the ideas of generic RDF graph visualization and RDF Schema-based form generation. In this paper, we present a comprehensive platform for constructing end user applications that create, manipulate, and visualize arbitrary RDF-encoded information, adding another layer to the abstraction cake. We discuss a programming environment specifically designed for manipulating RDF and introduce user interface concepts on top that allow the developer to quickly assemble applications that are based on RDF data models. Also, because user interface specifications and program logic are themselves describable in RDF, applications built upon our framework enjoy properties such as network updatability, extensibility, and end user customizability – all desirable characteristics in the spirit of the Semantic Web.Wed Jun 17 10:33:20 CEST 2009Scientific Americanmay534--43The Semantic Web2842001semantic web A new form of Web content that is meaningful to computers will unleash a revolution of new possibilitiesWed Jun 17 10:02:21 CEST 2009Galway, IrelandmayDERI-TR-2004-05-02The Social Semantic Desktop2004desktop semantic social This whitepaper we vision of a new group collaboration infrastructure, the Social Semantic Desktop, drawing from co-evolving research in the Semantic Web, Peer-to-Peer (P2P) Networks, and Online Social Networking. The Social Semantic Desktop is a novel collaboration environment, enabling the creation, sharing and deployment of data and metadata.Wed Jun 17 09:55:26 CEST 2009Proceedings of the 1st Workshop on The Semantic Desktop at the ISWC 2005 Conferencenov1 -- 18CEUR-WS.orgOverview and Outlook on the Semantic Desktop1752005desktop semantic seminar2006 In this paper we will give an overview of the Semantic Desktop paradigm, beginning with the history of the term, a definition, current work and its relevance to knowledge management of the future. Existing applications and research results are listed and their role as building blocks of the future Semantic Desktop described. Based on the analysis of existing systems we propose two software architecture paradigms, one for the Semantic Desktop at large and an other for applications running on a Semantic Desktop. A view on the context aspect of the Semantic Desktop and the Knowledge Management aspect is given. Based on the current events and projects, we give an outlook on the next steps. Wed Jun 10 14:32:27 CEST 2009Proceedings of the Semantic Desktop and Social Semantic Collaboration Workshop (SemDesk 2006) at the 5th International Semantic Web Conference ISWC 2006novCEUR-WS.orgThe Beagle++ Toolbox: Towards an Extendable Desktop Search Architecture2022006beagle++ desktop search semantic The rapidly increasing quantity and diversity of data stored on our PCs made locating information in this environment very difficult. Consequently, recent research has focussed on building semantically enhanced systems for either organizing or searching data on the desktop. Building on previous work, in this paper we present the Beagle++ toolbox, a set of extendable building blocks for implementing such a system. The corresponding modular desktop search architecture integrates our previously developed metadata generators and ranking components, uses an RDF database to share data between components, and can easily integrate other external components to improve desktop search quality. Additionally, we provide implementation details about all our current components, how they interact with each other, and how to install the complete system on top of a Linux distribution.Mon May 25 17:12:10 CEST 2009Graz, AustriaProceedings of the 6th International Conference on Knowledge Management (I-KNOW 06)sepTagFS - Tag Semantics for Hierarchical File Systems2006file semantic semfs system tagfs tagging Today, most computer users work with traditional hierarchical file systems for organizing large amounts of personal files. Recently, tagging has grown popular as an alternative means of organizing information resources. We argue that tagging is a powerful paradigm for efficient information access which overcomes many deficiencies of hierarchical file systems, especially in the context of the organization of large quantities of personal files. In this paper we present TagFS, a filesystem with tagging support which aims at a seamless integration of the tagging paradigm with local applications. While retaining the notions of directories and files and providing all standard filesystem operations, the semantics of these primitives are changed to modifications of the tag annotations.Wed May 13 15:09:47 CEST 2009Amsterdam, The NetherlandsWeb Semantics: Science, Services and Agents on the World Wide Web4283--290Recommendations based on semantically enriched museum collections62008content recommender semantic web This article presents the CHIP demonstrator for providing personalized access to digital museum collections. It consists of three main components: Art Recommender, Tour Wizard, and Mobile Tour Guide. Based on the semantically enriched Rijksmuseum Amsterdam collection, we show how Semantic Web technologies can be deployed to (partially) solve three important challenges for recommender systems applied in an open Web context: (1) to deal with the complexity of various types of relationships for recommendation inferencing, where we take a content-based approach to recommend both artworks and art-history topics; (2) to cope with the typical user modeling problems, such as cold-start for first-time users, sparsity in terms of user ratings, and the efficiency of user feedback collection; and (3) to support the presentation of recommendations by combining different views like a historical timeline, museum map and faceted browser. Following a user-centered design cycle, we have performed two evaluations with users to test the effectiveness of the recommendation strategy and to compare the different ways for building an optimal user profile for efficient recommendations. The CHIP demonstrator received the Semantic Web Challenge Award (third prize) in 2007, Busan, Korea.Wed May 13 13:55:27 CEST 2009Proceedings of I-Semantics' 07297-304ConTag: A semantic tag recommendation system2007contag recommender semantic tag web ConTag is an approach to generate semantic tag recommendations for documents based on Semantic Web ontologies and Web 2.0 services. We designed and implemented a process to normalize documents to RDF format, extract document topics using Web 2.0 services and finally match extracted topics to a Semantic web ontology. Due to ConTag we are able to show that the information provided by Web 2.0 services in combination with a Semantic Web ontology enables the generation of relevant semantic tag recommendations for documents. The main contribution of this work is a semantic tag recommendation process based on a choreography of Web 2.0 services.