@inproceedings{jaeschke06wege, abstract = {Ein wichtiger Baustein des neu entdeckten World Wide Web -- des "Web 2.0" -- stellen Folksonomies dar. In diesen Systemen können Benutzer gemeinsam Ressourcen verwalten und mit Schlagwörtern versehen. Die dadurch entstehenden begrifflichen Strukturen stellen ein interessantes Forschungsfeld dar. Dieser Artikel untersucht Ansätze und Wege zur Entdeckung und Strukturierung von Nutzergruppen ("Communities") in Folksonomies.}, address = {Halle-Wittenberg}, author = {Jäschke, Robert and Hotho, Andreas and Schmitz, Christoph and Stumme, Gerd}, booktitle = {Proc. 18. Workshop Grundlagen von Datenbanken}, editor = {Braß, Stefan and Hinneburg, Alexander}, interhash = {59224b5889a24108434a9b5ecc6b0887}, intrahash = {2b6be3bd5daee7119973fcf69909956f}, month = {June}, pages = {80-84}, publisher = {Martin-Luther-Universität }, title = {Wege zur Entdeckung von Communities in Folksonomies}, url = {http://www.kde.cs.uni-kassel.de/jaeschke/pub/jaeschke2006wege_gvd.pdf}, year = 2006 } @inproceedings{jaeschke2006trias, address = {Hong Kong}, author = {Jäschke, Robert and Hotho, Andreas and Schmitz, Christoph and Ganter, Bernhard and Stumme, Gerd}, booktitle = {Proceedings of the 6th IEEE International Conference on Data Mining (ICDM 06)}, doi = {http://doi.ieeecomputersociety.org/10.1109/ICDM.2006.162}, interhash = {b4964c3bdd2991a80873d7080ef6a73e}, intrahash = {e387c294129e11f4221514d5fa807e26}, isbn = {0-7695-2701-9}, issn = {1550-4786}, month = {December}, pages = {907-911}, publisher = {IEEE Computer Society}, title = {TRIAS - An Algorithm for Mining Iceberg Tri-Lattices}, url = {http://www.kde.cs.uni-kassel.de/pub/pdf/jaeschke2006trias.pdf}, vgwort = {19}, year = 2006 } @inproceedings{hotho2006trend, abstract = {As the number of resources on the web exceeds by far the number of documents one can track, it becomes increasingly difficult to remain up to date on ones own areas of interest. The problem becomes more severe with the increasing fraction of multimedia data, from which it is difficult to extract some conceptual description of their contents. One way to overcome this problem are social bookmark tools, which are rapidly emerging on the web. In such systems, users are setting up lightweight conceptual structures called folksonomies, and overcome thus the knowledge acquisition bottleneck. As more and more people participate in the effort, the use of a common vocabulary becomes more and more stable. We present an approach for discovering topic-specific trends within folksonomies. It is based on a differential adaptation of the PageRank algorithm to the triadic hypergraph structure of a folksonomy. The approach allows for any kind of data, as it does not rely on the internal structure of the documents. In particular, this allows to consider different data types in the same analysis step. We run experiments on a large-scale real-world snapshot of a social bookmarking system.}, address = {Heidelberg}, author = {Hotho, Andreas and Jäschke, Robert and Schmitz, Christoph and Stumme, Gerd}, booktitle = {Proc. First International Conference on Semantics And Digital Media Technology (SAMT) }, date = {2006-12-13}, editor = {Avrithis, Yannis S. and Kompatsiaris, Yiannis and Staab, Steffen and O'Connor, Noel E.}, ee = {http://dx.doi.org/10.1007/11930334_5}, interhash = {227be738c5cea57530d592463fd09abd}, intrahash = {42cda5911e901eadd0ac6a106a6aa1dc}, isbn = {3-540-49335-2}, month = dec, pages = {56-70}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, title = {Trend Detection in Folksonomies}, url = {http://www.kde.cs.uni-kassel.de/stumme/papers/2006/hotho2006trend.pdf}, vgwort = {27}, volume = 4306, year = 2006 } @inproceedings{jaeschke07tagKdml, abstract = {Collaborative tagging systems allow users to assign keywords—so called “tags”—to resources. Tags are used for navigation, finding resources and serendipitous browsing and thus provide an immediate benefit for users. These systems usually include tag recommendation mechanisms easing the process of finding good tags for a resource, but also consolidating the tag vocabulary across users. In practice, however, only very basic recommendation strategies are applied. In this paper we present two tag recommendation algorithms: an adaptation of user-based collaborative filtering and a graph-based recommender built on top of FolkRank, an adaptation of the well-known PageRank algorithm that can cope with undirected triadic hyperedges. We evaluate and compare both algorithms on large-scale real life datasets and show that both provide better results than non-personalized baseline methods. Especially the graph-based recommender outperforms existing methods considerably.}, author = {Jäschke, Robert and Marinho, Leandro and Hotho, Andreas and Schmidt-Thieme, Lars and Stumme, Gerd}, booktitle = {Workshop Proceedings of Lernen - Wissensentdeckung - Adaptivität (LWA 2007)}, editor = {Hinneburg, Alexander}, interhash = {7e212e3bac146d406035adebff248371}, intrahash = {bfc43dfe59f9c0935ac3364b12e6d795}, isbn = {978-3-86010-907-6}, month = sep, pages = {13-20}, publisher = {Martin-Luther-Universität Halle-Wittenberg}, title = {Tag Recommendations in Folksonomies}, url = {http://www.kde.cs.uni-kassel.de/stumme/papers/2007/jaeschke07tagrecommendationsKDML.pdf}, vgwort = {20}, year = 2007 } @inproceedings{jaeschke2007tag, abstract = {Collaborative tagging systems allow users to assign keywords—so called “tags”—to resources. Tags are used for navigation, finding resources and serendipitous browsing and thus provide an immediate benefit for users. These systems usually include tag recommendation mechanisms easing the process of finding good tags for a resource, but also consolidating the tag vocabulary across users. In practice, however, only very basic recommendation strategies are applied. In this paper we evaluate and compare two recommendation algorithms on largescale real life datasets: an adaptation of user-based collaborative filtering and a graph-based recommender built on top of FolkRank. We show that both provide better results than non-personalized baseline methods. Especially the graph-based recommender outperforms existing methods considerably.}, address = {Berlin, Heidelberg}, author = {Jäschke, Robert and Balby Marinho, Leandro and Hotho, Andreas and Schmidt-Thieme, Lars and Stumme, Gerd}, booktitle = {Knowledge Discovery in Databases: PKDD 2007, 11th European Conference on Principles and Practice of Knowledge Discovery in Databases}, editor = {Kok, Joost N. and Koronacki, Jacek and de Mántaras, Ramon López and Matwin, Stan and Mladenic, Dunja and Skowron, Andrzej}, ee = {http://dx.doi.org/10.1007/978-3-540-74976-9_52}, interhash = {7e212e3bac146d406035adebff248371}, intrahash = {bb8ecec699a2f129322fe334747c6aef}, isbn = {978-3-540-74975-2}, pages = {506-514}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, title = {Tag Recommendations in Folksonomies}, url = {http://dx.doi.org/10.1007/978-3-540-74976-9_52}, vgwort = {14}, volume = 4702, year = 2007 } @incollection{hotho2008social, abstract = {BibSonomy ist ein kooperatives Verschlagwortungssystem (Social Bookmarking System), betrieben vom Fachgebiet Wissensverarbeitung der Universität Kassel. Es erlaubt das Speichern und Organisieren von Web-Lesezeichen und Metadaten für wissenschaftlichePublikationen. In diesem Beitrag beschreiben wir die von BibSonomy bereitgestellte Funktionalität, die dahinter stehende Architektursowie das zugrunde liegende Datenmodell. Ferner erläutern wir Anwendungsbeispiele und gehen auf Methoden zur Analyse der in BibSonomy und ähnlichen Systemen enthaltenen Daten ein.}, address = {Berlin, Heidelberg}, author = {Hotho, Andreas and Jäschke, Robert and Benz, Dominik and Grahl, Miranda and Krause, Beate and Schmitz, Christoph and Stumme, Gerd}, booktitle = {Social Semantic Web}, chapter = 18, doi = {10.1007/978-3-540-72216-8}, editor = {Blumauer, Andreas and Pellegrini, Tassilo}, interhash = {79dbca4289cfe913aa7f7eb7e0dccea7}, intrahash = {5ccf05a86e7f1a089ae83dd47568e6de}, isbn = {978-3-540-72215-1}, issn = {1439-3107}, pages = {363--391}, publisher = {Springer}, series = {X.media.press}, title = {Social Bookmarking am Beispiel BibSonomy}, url = {http://dx.doi.org/10.1007/978-3-540-72216-8_18}, vgwort = {49}, year = 2009 } @incollection{hoser2006semantic, abstract = { 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. }, address = {Berlin/Heidelberg}, author = {Hoser, Bettina and Hotho, Andreas and Jäschke, Robert and Schmitz, Christoph and Stumme, Gerd}, booktitle = {The Semantic Web: Research and Applications}, doi = {10.1007/11762256_38}, editor = {Sure, York and Domingue, John}, interhash = {344ec3b4ee8af1a2c6b86efc14917fa9}, intrahash = {2b720233e4493d4e0dee95be86dd07e8}, isbn = {978-3-540-34544-2}, note = {10.1007/11762256_38}, pages = {514--529}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, title = {Semantic Network Analysis of Ontologies}, url = {http://dx.doi.org/10.1007/11762256_38}, volume = 4011, year = 2006 } @inproceedings{jaeschke07organizing, address = {Banff, Canada}, author = {Jäschke, Robert and Grahl, Miranda and Hotho, Andreas and Krause, Beate and Schmitz, Christoph and Stumme, Gerd}, booktitle = {Workshop on Social and Collaborative Construction of Structured Knowledge (CKC 2007) at WWW 2007}, editor = {Alani, Harith and Noy, Natasha and Stumme, Gerd and Mika, Peter and Sure, York and Vrandecic, Denny}, interhash = {3fb8454b742da78867511789ff985719}, intrahash = {b3a5e9851647ca0a7dfb62f041872504}, month = may, title = {Organizing Publications and Bookmarks in BibSonomy}, url = {http://www2007.org/workshops/paper_25.pdf}, year = 2007 } @inproceedings{schmitz2006mining, address = {Berlin, Heidelberg}, annote = {Proc. of the 10th IFCS Conf.}, author = {Schmitz, Christoph and Hotho, Andreas and Jäschke, Robert and Stumme, Gerd}, booktitle = {Data Science and Classification}, editor = {Batagelj, V. and Bock, H.-H. and Ferligoj, A. and Žiberna, A.}, interhash = {20650d852ca3b82523fcd8b63e7c12d7}, intrahash = {7f502f47bd0e584190337e3e2d4eba9e}, isbn = {978-3-540-34415-5}, pages = {261--270}, publisher = {Springer}, series = {Studies in Classification, Data Analysis, and Knowledge Organization}, title = {Mining Association Rules in Folksonomies}, year = 2006 } @inproceedings{Jaeschke2008logsonomy, abstract = {In social bookmarking systems users describe bookmarks by keywords called tags. The structure behind these social systems, called folksonomies, can be viewed as a tripartite hypergraph of user, tag and resource nodes. This underlying network shows specific structural properties that explain its growth and the possibility of serendipitous exploration. Search engines filter the vast information of the web. Queries describe a user’s information need. In response to the displayed results of the search engine, users click on the links of the result page as they expect the answer to be of relevance. The clickdata can be represented as a folksonomy in which queries are descriptions of clicked URLs. This poster analyzes the topological characteristics of the resulting tripartite hypergraph of queries, users and bookmarks of two query logs and compares it two a snapshot of the folksonomy del.icio.us. }, address = {Menlo Park, CA, USA}, author = {Jäschke, Robert and Krause, Beate and Hotho, Andreas and Stumme, Gerd}, booktitle = {Proceedings of the Second International Conference on Weblogs and Social Media (ICWSM 2008)}, interhash = {13ec3f45fc7e0364cdc6b9a7c12c5c2c}, intrahash = {7eb26a177187ea8cf788cc897d66ee48}, isbn = {978-1-57735-355-3}, pages = {192--193}, publisher = {AAAI Press}, title = {Logsonomy -- A Search Engine Folksonomy}, url = {http://www.kde.cs.uni-kassel.de/hotho/pub/2008/Krause2008logsonomy_short.pdf}, vgwort = {7}, year = 2008 } @inproceedings{krause2008logsonomy, abstract = {Social bookmarking systems constitute an established part of the Web 2.0. In such systems users describe bookmarks by keywords called tags. The structure behind these social systems, called folksonomies, can be viewed as a tripartite hypergraph of user, tag and resource nodes. This underlying network shows specific structural properties that explain its growth and the possibility of serendipitous exploration. Today’s search engines represent the gateway to retrieve information from the World Wide Web. Short queries typically consisting of two to three words describe a user’s information need. In response to the displayed results of the search engine, users click on the links of the result page as they expect the answer to be of relevance. This clickdata can be represented as a folksonomy in which queries are descriptions of clicked URLs. The resulting network structure, which we will term logsonomy is very similar to the one of folksonomies. In order to find out about its properties, we analyze the topological characteristics of the tripartite hypergraph of queries, users and bookmarks on a large snapshot of del.icio.us and on query logs of two large search engines. All of the three datasets show small world properties. The tagging behavior of users, which is explained by preferential attachment of the tags in social bookmark systems, is reflected in the distribution of single query words in search engines. We can conclude that the clicking behaviour of search engine users based on the displayed search results and the tagging behaviour of social bookmarking users is driven by similar dynamics.}, address = {New York, NY, USA}, author = {Krause, Beate and Jäschke, Robert and Hotho, Andreas and Stumme, Gerd}, booktitle = {HT '08: Proceedings of the Nineteenth ACM Conference on Hypertext and Hypermedia}, doi = {10.1145/1379092.1379123}, interhash = {6d34ea1823d95b9dbf37d4db4d125d2a}, intrahash = {e64d14f3207766f4afc65983fa759ffe}, isbn = {978-1-59593-985-2}, location = {Pittsburgh, PA, USA}, pages = {157--166}, publisher = {ACM}, title = {Logsonomy - Social Information Retrieval with Logdata}, url = {http://www.kde.cs.uni-kassel.de/pub/pdf/krause2008logsonomy.pdf}, vgwort = {17}, year = 2008 } @inbook{schmitz2006kollaboratives, abstract = {Wissensmanagement in zentralisierten Wissensbasen erfordert einen hohen Aufwand für Erstellung und Wartung, und es entspricht nicht immer den Anforderungen der Benutzer. Wir geben in diesem Kapitel einen Überblick über zwei aktuelle Ansätze, die durch kollaboratives Wissensmanagement diese Probleme lösen können. Im Peer-to-Peer-Wissensmanagement unterhalten Benutzer dezentrale Wissensbasen, die dann vernetzt werden können, um andere Benutzer eigene Inhalte nutzen zu lassen. Folksonomies versprechen, die Wissensakquisition so einfach wie möglich zu gestalten und so viele Benutzer in den Aufbau und die Pflege einer gemeinsamen Wissensbasis einzubeziehen.}, author = {Schmitz, Christoph and Hotho, Andreas and Jäschke, Robert and Stumme, Gerd}, booktitle = {Semantic Web - Wege zur vernetzten Wissensgesellschaft}, editor = {Pellegrini, Tassilo and Blumauer, Andreas}, interhash = {cc0f3d4fa8f36968f02837e3f9f5c57b}, intrahash = {53e13744981f2c04d9239e0cf9b4e689}, isbn = {3-540-29324-8}, pages = {273-290}, publisher = {Springer}, title = {Kollaboratives Wissensmanagement}, url = {http://www.kde.cs.uni-kassel.de/stumme/papers/2006/hotho2006kollaboratives.pdf}, year = 2006 } @inproceedings{hotho2006information, abstract = {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. At the moment, however, the information retrieval support is limited. We present a formal model and a new search algorithm for folksonomies, called FolkRank, that exploits the structure of the folksonomy. The proposed algorithm is also applied to find communities within the folksonomy and is used to structure search results. All findings are demonstrated on a large scale dataset.}, address = {Heidelberg}, author = {Hotho, Andreas and Jäschke, Robert and Schmitz, Christoph and Stumme, Gerd}, booktitle = {The Semantic Web: Research and Applications}, editor = {Sure, York and Domingue, John}, interhash = {10ec64d80b0ac085328a953bb494fb89}, intrahash = {3c301945817681d637ee43901c016939}, month = {June}, pages = {411-426}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, title = {Information Retrieval in Folksonomies: Search and Ranking}, volume = 4011, year = 2006 } @inproceedings{hotho2006emergent, abstract = {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.}, address = {Bonn}, author = {Hotho, Andreas and Jäschke, Robert and Schmitz, Christoph and Stumme, Gerd}, booktitle = {Informatik 2006 - Informatik für Menschen}, editor = {Hochberger, Christian and Liskowsky, Rüdiger}, interhash = {53e5677ab0bf1a8f5a635cc32c9082ba}, intrahash = {7a05c4bf8b724bc02841bd58c7eea90d}, isbn = {978-3-88579-188-1}, issn = {1617-5468}, month = oct, pages = {305--312}, publisher = {Gesellschaft für Informatik}, series = {Lecture Notes in Informatics}, title = {Emergent Semantics in BibSonomy}, url = {http://www.kde.cs.uni-kassel.de/stumme/papers/2006/hotho2006emergent.pdf}, vgwort = {14}, volume = 94, year = 2006 } @article{jaeschke2008discovering, abstract = {Social bookmarking tools are rapidly emerging on the Web. In such systems users are setting up lightweight conceptual structures called folksonomies. Unlike ontologies, shared conceptualizations are not formalized, but rather implicit. We present a new data mining task, the mining of all frequent tri-concepts, together with an efficient algorithm, for discovering these implicit shared conceptualizations. Our approach extends the data mining task of discovering all closed itemsets to three-dimensional data structures to allow for mining folksonomies. We provide a formal definition of the problem, and present an efficient algorithm for its solution. Finally, we show the applicability of our approach on three large real-world examples.}, address = {New York}, author = {Jäschke, Robert and Hotho, Andreas and Schmitz, Christoph and Ganter, Bernhard and Stumme, Gerd}, booktitle = {Semantic Web and Web 2.0}, doi = {10.1016/j.websem.2007.11.004}, editor = {Finin, T. and Mizoguchi, R. and Staab, S.}, interhash = {cfca594f9dbe30694bfbcdeb40dc4e88}, intrahash = {18e8babe208fae2c0342438617b0ec31}, issn = {1570-8268}, journal = {Web Semantics: Science, Services and Agents on the World Wide Web}, month = feb, number = 1, pages = {38--53}, publisher = {Elsevier}, title = {Discovering Shared Conceptualizations in Folksonomies}, url = {http://www.kde.cs.uni-kassel.de/pub/pdf/jaeschke2008discovering.pdf}, vgwort = {59}, volume = 6, year = 2008 } @inproceedings{schmitz2006content, abstract = {Recently, research projects such as PADLR and SWAP have developed tools like Edutella or Bibster, which are targeted at establishing peer-to-peer knowledge management (P2PKM) systems. In such a system, it is necessary to obtain provide brief semantic descriptions of peers, so that routing algorithms or matchmaking processes can make decisions about which communities peers should belong to, or to which peers a given query should be forwarded. This paper provides a graph clustering technique on knowledge bases for that purpose. Using this clustering, we can show that our strategy requires up to 58% fewer queries than the baselines to yield full recall in a bibliographic P2PKM scenario.}, address = {Berlin/Heidelberg}, author = {Schmitz, Christoph and Hotho, Andreas and Jäschke, Robert and Stumme, Gerd}, booktitle = {The Semantic Web: Research and Applications}, doi = {10.1007/11762256_39}, editor = {Sure, York and Domingue, John}, interhash = {d2ddbb8f90cd271dc18670e4c940ccfb}, intrahash = {1788c88e04112a4491f19dfffb8dc39e}, isbn = {978-3-540-34544-2}, issn = {0302-9743}, month = jun, pages = {530--544}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, title = {Content Aggregation on Knowledge Bases using Graph Clustering}, url = {http://www.springerlink.com/content/u121v1827v286398/}, volume = 4011, year = 2006 } @inproceedings{hjss06bibsonomy, address = {Aalborg, Denmark}, author = {Hotho, Andreas and Jäschke, Robert and Schmitz, Christoph and Stumme, Gerd}, booktitle = {Proceedings of the Conceptual Structures Tool Interoperability Workshop at the 14th International Conference on Conceptual Structures}, editor = {de Moor, Aldo and Polovina, Simon and Delugach, Harry}, interhash = {d28c9f535d0f24eadb9d342168836199}, intrahash = {2cbd8e3236adea7c54779605a5aa4fd6}, isbn = {87-7307-769-0}, month = jul, publisher = {Aalborg University Press}, title = {{BibSonomy}: A Social Bookmark and Publication Sharing System}, url = {http://www.kde.cs.uni-kassel.de/pub/pdf/hotho06bibsonomy.pdf}, vgwort = {27}, year = 2006 } @inproceedings{jaeschke2007analysis, abstract = {BibSonomy is a web-based social resource sharing system which allows users to organise and share bookmarks and publications in a collaborative manner. In this paper we present the system, followed by a description of the insights in the structure of its bibliographic data that we gained by applying techniques we developed in the area of Formal Concept Analysis.}, address = {Berlin, Heidelberg}, author = {Jäschke, Robert and Hotho, Andreas and Schmitz, Christoph and Stumme, Gerd}, booktitle = {Proceedings of the 15th International Conference on Conceptual Structures (ICCS 2007)}, editor = {Priss, U. and Polovina, S. and Hill, R.}, interhash = {4352d1142afa561460511b22d4ce5103}, intrahash = {0c2b212b9ea3d822bf4729fd5fe6b6e1}, isbn = {3-540-73680-8}, month = {July}, pages = {283--295}, publisher = {Springer-Verlag}, series = {Lecture Notes in Artificial Intelligence}, title = {Analysis of the Publication Sharing Behaviour in {BibSonomy}}, vgwort = {22}, volume = 4604, year = 2007 }