TY - CONF AU - Cattuto, Ciro AU - Benz, Dominik AU - Hotho, Andreas AU - Stumme, Gerd A2 - T1 - Semantic Analysis of Tag Similarity Measures in Collaborative Tagging Systems T2 - Proceedings of the 3rd Workshop on Ontology Learning and Population (OLP3) PB - CY - Patras, Greece PY - 2008/07 M2 - VL - IS - SP - EP - UR - http://olp.dfki.de/olp3/ M3 - KW - 2.0 KW - 2008 KW - collaborative KW - folksonomies KW - folksonomy KW - itegpub KW - myown KW - semantic KW - systems KW - tagging KW - web KW - web2.0 L1 - SN - N1 - Publications of Gerd Stumme N1 - AB - Social bookmarking systems allow users to organise collections of resources on the Web in a collaborative fashion. The increasing popularity of these systems as well as first insights into their emergent semantics have made them relevant to disciplines like knowledge extraction and ontology learning. The problem of devising methods to measure the semantic relatedness between tags and characterizing it semantically is still largely open. Here we analyze three measures of tag relatedness: tag co-occurrence, cosine similarity of co-occurrence distributions, and FolkRank, an adaptation of the PageRank algorithm to folksonomies. Each measure is computed on tags from a large-scale dataset crawled from the social bookmarking system del.icio.us. To provide a semantic grounding of our findings, a connection to WordNet (a semantic lexicon for the English language) is established by mapping tags into synonym sets of WordNet, and applying there well-known metrics of semantic similarity. Our results clearly expose different characteristics of the selected measures of relatedness, making them applicable to different subtasks of knowledge extraction such as synonym detection or discovery of concept hierarchies. ER - TY - JOUR AU - Jäschke, Robert AU - Marinho, Leandro AU - Hotho, Andreas AU - Schmidt-Thieme, Lars AU - Stumme, Gerd T1 - Tag Recommendations in Social Bookmarking Systems JO - AI Communications PY - 2008/ VL - 21 IS - 4 SP - 231 EP - 247 UR - http://dx.doi.org/10.3233/AIC-2008-0438 M3 - 10.3233/AIC-2008-0438 KW - 2.0 KW - 2008 KW - Recommendations KW - bookmarking KW - itegpub KW - logsonomies KW - myown KW - recommendations KW - recommender KW - social KW - systems KW - tag KW - tagorapub KW - tags KW - web KW - web2.0 KW - web20 L1 - SN - N1 - N1 - AB - 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 several recommendation algorithms on large-scale real life datasets: an adaptation of

user-based collaborative filtering, a graph-based recommender built on top of the FolkRank algorithm, and simple methods based on counting tag occurences. We show that both FolkRank and Collaborative Filtering provide better results than non-personalized baseline methods. Moreover, since methods based on counting tag occurrences are computationally cheap, and thus usually preferable for real time scenarios, we discuss simple approaches for improving the performance of such methods. We show, how a simple recommender based on counting tags from users and resources can perform almost as good as the best recommender.

ER - TY - CONF AU - Krause, Beate AU - Schmitz, Christoph AU - Hotho, Andreas AU - Stumme, Gerd A2 - T1 - The Anti-Social Tagger - Detecting Spam in Social Bookmarking Systems T2 - Proc. of the Fourth International Workshop on Adversarial Information Retrieval on the Web PB - CY - PY - 2008/ M2 - VL - IS - SP - EP - UR - http://airweb.cse.lehigh.edu/2008/submissions/krause_2008_anti_social_tagger.pdf M3 - KW - 2.0 KW - 2008 KW - bookmarking KW - folksonomies KW - folksonomy KW - itegpub KW - myown KW - social KW - spam KW - systems KW - tagger KW - tagorapub KW - web KW - web2.0 L1 - SN - N1 - Publications of Gerd Stumme N1 - AB - ER - TY - CHAP AU - Alfi, V. AU - Parisi, G. AU - Pietronero, L. A2 - Pietronero, Luciano A2 - Loreto, Vittorio A2 - Zapperi, Stefano T1 - How People React to a Deadline: The Distribution of Registrations of Statphys 23 T2 - Abstract Book of the XXIII IUPAP International Conference on Statistical Physics PB - CY - Genova, Italy PY - 2007/9-13 july VL - IS - SP - EP - UR - http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=1122 M3 - KW - complex KW - deadline KW - distribution KW - dynamics KW - registration KW - social KW - statphys KW - systems L1 - SN - N1 - N1 - AB - In Fig. 1 we show the number of registrations to Statphys 23

(full dots).

Each point corresponds to one day and the deadline $T^*$=March 31 was

the one corresponding to the early registration and abstract submission.

We also plot the data corresponding to the a different conference

(EP2DS 17)

for which we have rescaled the total number of registration at its

own $T^*$.

The data of the two conferences are remarkably similar

and are characterized by an initial linear behavior followed

by a strong increase near $T^*$.

This strong similarity suggests for a simple mechanism to describe

the response of the people to a deadline and we propose have a

simple model.

The basic idea is that the pressure you have to register is proportional

to the inverse of the remaining time to the deadline.

This gives a probability, $p(t)$, to register at time $t$ that is $p(t)p>frac 1(T^*-t)$.

From this the number of the registrations at time $t$ is:

$$

N(t)=C0^T^*p(t)dt=A(N_tot)T^*T^*-t).

p>$$

The logarithmic singularity at the end is regularized by discretizing the

integral with an interval of one day and the constant $A(N_tot)$

is fixed by the total number of final registration $N_tot$.

As one can see in Fig. 1 this simple model fits the

observed behavior extremely well.

This permits to predict the total number of registrations

already from the initial slope.

A result that could have some practical interest.

The model only assumes that the probability to register

is the same for the whole interval of the the remaining time.

In this respect there is no real tendency to shift the registration

towards the deadline.

The increase of pressure is just due to the approaching of the deadline.

This situation may appear curious because one could have expected

a stronger pressure to postpone the payment towards the deadline.

In this respect, however, one should notice that the data in Fig. 1

refer only to the registration and not to the payment of the fee which

could have been done also at a late time. ER - TY - CONF AU - Hereth, J. AU - Stumme, G. A2 - Delugach, H. A2 - Stumme, G. T1 - Reverse Pivoting in Conceptual Information Systems. T2 - Conceptual Structures: Broadening the Base. PB - Springer CY - Heidelberg PY - 2001/ M2 - VL - 2120 IS - SP - 202 EP - 215 UR - http://www.kde.cs.uni-kassel.de/stumme/papers/2001/ICCS01.pdf M3 - KW - 2001 KW - analysis KW - concept KW - conceptual KW - fca KW - formal KW - information KW - myown KW - pivoting KW - reverse KW - systems KW - toscana L1 - SN - N1 - Publications of Gerd Stumme N1 - AB - ER - TY - CONF AU - Becker, K. AU - Stumme, G. AU - Wille, R. AU - Wille, U. AU - Zickwolff, M. A2 - Dieng, R. A2 - Corby, O. T1 - Conceptual Information Systems Discussed Through an IT-Security Tool T2 - Knowledge Engineering and Knowledge Management. Methods, Models, and Tools. PB - Springer CY - Heidelberg PY - 2000/ M2 - VL - 1937 IS - SP - 352 EP - 365 UR - http://www.kde.cs.uni-kassel.de/stumme/papers/2000/EKAW00.pdf M3 - KW - 2000 KW - OntologyHandbook KW - analysis KW - concept KW - conceptual KW - fca KW - formal KW - information KW - it KW - lattices KW - myown KW - security KW - system KW - systems KW - triadic L1 - SN - N1 - alpha N1 - AB - ER - TY - CONF AU - Göbel, S. AU - Heidemann, M. AU - Jasnoch, U. AU - Stumme, G. A2 - Tochtermann, K. A2 - Riekert, W.-F. T1 - Einsatz von GIS und Formaler Begriffsanalyse in

Altlasten-Informationssystemen T2 - Hypermedia im Umweltschutz. 3. Workshop in Ulm 2000 PB - CY - Marburg PY - 2000/ M2 - VL - Umwelt-Informatik aktuell, Bd. 24 IS - SP - 169 EP - 179 UR - http://www.kde.cs.uni-kassel.de/stumme/papers/2000/AKHU00.pdf M3 - KW - 2000 KW - altlasten KW - analysis KW - concept KW - fca KW - formal KW - geo KW - geographical KW - gis KW - informations KW - lattices KW - myown KW - systems L1 - SN - N1 - Publications of Gerd Stumme N1 - AB - ER - TY - CONF AU - Stumme, G. AU - Wolff, K. E. A2 - Kambayashi, Y. A2 - Lee, Dik Kun A2 - Lim, Ee-Peng A2 - Mohania, M. K. A2 - Masunaga, Y. T1 - Numerical Aspects in the Data Model of Conceptual Information Systems T2 - Advances in Database Technologies. Proc. Intl. Workshop on Data Warehousing and PB - Springer CY - Heidelberg PY - 1999/ M2 - VL - 1552 IS - SP - 117 EP - 128 UR - http://www.kde.cs.uni-kassel.de/stumme/papers/1998/ER98.pdf M3 - KW - 1999 KW - analysis KW - concept KW - conceptual KW - fca KW - formal KW - information KW - myown KW - numerical KW - scaling KW - systems KW - toscana L1 - SN - N1 - Publications of Gerd Stumme N1 - AB - ER - TY - CONF AU - Stumme, Gerd A2 - Fensel, D. A2 - Studer, R. T1 - Acquiring Expert Knowledge for the Design of Conceptual Information Systems T2 - Knowledge Acquisition, Modeling, and Management. Proc. 11th European PB - Springer CY - Heidelberg PY - 1999/ M2 - VL - 1621 IS - SP - 275 EP - 290 UR - http://www.kde.cs.uni-kassel.de/stumme/papers/1999/P1997-EKAW99.pdf M3 - KW - 1999 KW - acquisition KW - analysis KW - attribute KW - concept KW - conceptual KW - exploration KW - fca KW - formal KW - information KW - knowledge KW - lattices KW - myown KW - systems L1 - SN - N1 - Publications of Gerd Stumme N1 - AB - ER - TY - CONF AU - Stumme, Gerd A2 - Buchmann, A. T1 - Dual Retrieval in Conceptual Information Systems T2 - Datenbanksysteme in Büro, Technik und Wissenschaft. Proc. BTW'99 PB - CY - Heidelberg PY - 1999/ M2 - VL - IS - SP - 328 EP - 342 UR - http://www.kde.cs.uni-kassel.de/stumme/papers/1999/P2021-BTW99.pdf M3 - KW - 1999 KW - analysis KW - concept KW - conceptual KW - fca KW - formal KW - information KW - myown KW - retrieval KW - systems KW - toscana L1 - SN - N1 - Publications of Gerd Stumme N1 - AB - ER - TY - CONF AU - Stumme, Gerd AU - Wolff, Karl Erich A2 - T1 - Computing in Conceptual Data systems with relational structures T2 - Proc. Intl. Symposium on Knowledge Retrieval, Use, and Storage for Efficiency PB - CY - Vancouver, Canada PY - 1997/aug 11-13 M2 - VL - IS - SP - 206 EP - 219 UR - http://www.kde.cs.uni-kassel.de/stumme/papers/1997/KRUSE97.pdf M3 - KW - 1997 KW - ag1 KW - analysis KW - begriffsanalyse KW - concept KW - conceptual KW - darmstadt KW - data KW - databases KW - fba KW - fca KW - formal KW - formale KW - forschungsgruppe KW - information KW - lattices KW - myown KW - relational KW - scaling KW - systems KW - tu L1 - SN - N1 - Publications of Gerd Stumme N1 - AB - ER - TY - BOOK AU - Stumme, Gerd A2 - T1 - Concept Exploration -- Knowledge Acquisition in Knowledge Systems. PB - Shaker AD - Aachen PY - 1997/ VL - IS - SP - EP - UR - http://www.shaker.de/Online-Gesamtkatalog/details.asp?ISBN=3-8265-2930-8 M3 - KW - 1997 KW - acquisition KW - analysis KW - attribute KW - concept KW - conceptual KW - exploration KW - fca KW - formal KW - knowledge KW - myown KW - systems L1 - SN - N1 - Publications of Gerd Stumme N1 - AB - ER -