TY - CONF AU - Doerfel, Stephan AU - Jäschke, Robert A2 - T1 - An analysis of tag-recommender evaluation procedures T2 - Proceedings of the 7th ACM conference on Recommender systems PB - ACM C1 - New York, NY, USA PY - 2013/ CY - VL - IS - SP - 343 EP - 346 UR - https://www.kde.cs.uni-kassel.de/pub/pdf/doerfel2013analysis.pdf DO - 10.1145/2507157.2507222 KW - 2013 KW - bibsonomy KW - bookmarking KW - collaborative KW - core KW - evaluation KW - folkrank KW - folksonomy KW - graph KW - iteg KW - itegpub KW - l3s KW - recommender KW - social KW - tagging L1 - SN - 978-1-4503-2409-0 N1 - N1 - AB - Since the rise of collaborative tagging systems on the web, the tag recommendation task -- suggesting suitable tags to users of such systems while they add resources to their collection -- has been tackled. However, the (offline) evaluation of tag recommendation algorithms usually suffers from difficulties like the sparseness of the data or the cold start problem for new resources or users. Previous studies therefore often used so-called post-cores (specific subsets of the original datasets) for their experiments. In this paper, we conduct a large-scale experiment in which we analyze different tag recommendation algorithms on different cores of three real-world datasets. We show, that a recommender's performance depends on the particular core and explore correlations between performances on different cores. ER - TY - JOUR AU - Heidtmann, Klaus T1 - Internet-Graphen JO - Informatik-Spektrum PY - 2013/ VL - 36 IS - 5 SP - 440 EP - 448 UR - http://dx.doi.org/10.1007/s00287-012-0654-z DO - 10.1007/s00287-012-0654-z KW - Graph KW - Graphen KW - Informatik KW - Informatik-Spektrum KW - Internet KW - Spektrum KW - graphs L1 - SN - N1 - Internet-Graphen - Springer N1 - AB - Bildeten die Keimzellen des Internet noch kleine und einfach strukturierte Netze, so vergrößerten sich sowohl seine physikalischen als auch seine logischen Topologien später rasant. Wuchs einerseits das Netz aus Rechnern als Knoten und Verbindungsleitungen als Kanten immer weiter, so bedienten sich andererseits gleichzeitig immer mehr Anwendungen dieser Infrastruktur, um darüber ihrerseits immer größere und komplexere virtuelle Netze zu weben, z. B. das WWW oder soziale Online-Netze. Auf jeder Ebene dieser Hierarchie lassen sich die jeweiligen Netztopologien mithilfe von Graphen beschreiben und so mathematisch untersuchen. So ergeben sich interessante Einblicke in die Struktureigenschaften unterschiedlicher Graphentypen, die großen Einfluss auf die Leistungsfähigkeit des Internet haben. Hierzu werden charakteristische Eigenschaften und entsprechende Kenngrößen verschiedener Graphentypen betrachtet wie der Knotengrad, die Durchschnittsdistanz, die Variation der Kantendichte in unterschiedlichen Netzteilen und die topologische Robustheit als Widerstandsfähigkeit gegenüber Ausfällen und Angriffen. Es wird dabei Bezug genommen auf analytische, simulative und zahlreiche empirische Untersuchungen des Internets und hingewiesen auf Simulationsprogramme sowie Abbildungen von Internetgraphen im Internet. ER - TY - JOUR AU - Landia, Nikolas AU - Doerfel, Stephan AU - Jäschke, Robert AU - Anand, Sarabjot Singh AU - Hotho, Andreas AU - Griffiths, Nathan T1 - Deeper Into the Folksonomy Graph: FolkRank Adaptations and Extensions for Improved Tag Recommendations JO - cs.IR PY - 2013/ VL - 1310.1498 IS - SP - EP - UR - http://arxiv.org/abs/1310.1498 DO - KW - 2013 KW - bookmarking KW - collaborative KW - folkrank KW - folksonomy KW - graph KW - iteg KW - itegpub KW - l3s KW - recommender KW - social KW - tagging L1 - SN - N1 - N1 - AB - The information contained in social tagging systems is often modelled as a graph of connections between users, items and tags. Recommendation algorithms such as FolkRank, have the potential to leverage complex relationships in the data, corresponding to multiple hops in the graph. We present an in-depth analysis and evaluation of graph models for social tagging data and propose novel adaptations and extensions of FolkRank to improve tag recommendations. We highlight implicit assumptions made by the widely used folksonomy model, and propose an alternative and more accurate graph-representation of the data. Our extensions of FolkRank address the new item problem by incorporating content data into the algorithm, and significantly improve prediction results on unpruned datasets. Our adaptations address issues in the iterative weight spreading calculation that potentially hinder FolkRank's ability to leverage the deep graph as an information source. Moreover, we evaluate the benefit of considering each deeper level of the graph, and present important insights regarding the characteristics of social tagging data in general. Our results suggest that the base assumption made by conventional weight propagation methods, that closeness in the graph always implies a positive relationship, does not hold for the social tagging domain. ER - TY - GEN AU - Ghosh, Rumi AU - Lerman, Kristina A2 - T1 - Structure of Heterogeneous Networks JO - PB - C1 - PY - 2009/ VL - IS - SP - EP - UR - http://arxiv.org/abs/0906.2212 DO - KW - graph KW - graphs KW - heterogenous KW - measures KW - multi-mode KW - networks KW - sna L1 - N1 - [0906.2212] Structure of Heterogeneous Networks N1 - AB - Heterogeneous networks play a key role in the evolution of communities and

the decisions individuals make. These networks link different types of

entities, for example, people and the events they attend. Network analysis

algorithms usually project such networks unto simple graphs composed of

entities of a single type. In the process, they conflate relations between

entities of different types and loose important structural information. We

develop a mathematical framework that can be used to compactly represent and

analyze heterogeneous networks that combine multiple entity and link types. We

generalize Bonacich centrality, which measures connectivity between nodes by

the number of paths between them, to heterogeneous networks and use this

measure to study network structure. Specifically, we extend the popular

modularity-maximization method for community detection to use this centrality

metric. We also rank nodes based on their connectivity to other nodes. One

advantage of this centrality metric is that it has a tunable parameter we can

use to set the length scale of interactions. By studying how rankings change

with this parameter allows us to identify important nodes in the network. We

apply the proposed method to analyze the structure of several heterogeneous

networks. We show that exploiting additional sources of evidence corresponding

to links between, as well as among, different entity types yields new insights

into network structure.

ER - TY - GEN AU - Noack, Andreas A2 - T1 - Modularity clustering is force-directed layout JO - PB - C1 - PY - 2008/ VL - IS - SP - EP - UR - http://www.citebase.org/abstract?id=oai:arXiv.org:0807.4052 DO - KW - clustering KW - communities KW - community KW - graph KW - layout KW - modularity KW - network KW - sna L1 - N1 - [0807.4052] Modularity clustering is force-directed layout N1 - AB - Two natural and widely used representations for the community structure of networks are clusterings, which partition the vertex set into disjoint subsets, and layouts, which assign the vertices to positions in a metric space. This paper unifies prominent characterizations of layout quality and clustering quality, by showing that energy models of pairwise attraction and repulsion subsume Newman and Girvan's modularity measure. Layouts with optimal energy are relaxations of, and are thus consistent with, clusterings with optimal modularity, which is of practical relevance because both representations are complementary and often used together. ER - TY - CONF AU - Zhu, Feida AU - Chen, Chen AU - Yan, Xifeng AU - Han, Jiawei AU - Yu, Philip S A2 - T1 - Graph OLAP: Towards Online Analytical Processing on Graphs T2 - Proc. 2008 Int. Conf. on Data Mining (ICDM'08), Pisa, Italy, Dec. 2008. PB - C1 - PY - 2008/12 CY - VL - IS - SP - EP - UR - DO - KW - graph KW - graphs KW - olap KW - sna L1 - SN - N1 - Resource: Graph OLAP: Towards Online Analytical Processing on Graphs N1 - AB - ER - TY - CONF AU - Hotho, Andreas AU - Jäschke, Robert AU - Schmitz, Christoph AU - Stumme, Gerd A2 - T1 - Information Retrieval in Folksonomies: Search and Ranking T2 - Proceedings of the 3rd European Semantic Web Conference PB - Springer C1 - PY - 2006/ CY - VL - IS - SP - 411 EP - 426 UR - DO - KW - FCA KW - OntologyHandbook KW - folkrank KW - folksonomy KW - graph KW - information KW - mining KW - pagerank KW - rank KW - ranking KW - retrieval KW - search KW - seminar2006 L1 - SN - N1 - N1 - AB - ER - TY - CONF AU - Schmitz, Christoph AU - Hotho, Andreas AU - Jäschke, Robert AU - Stumme, Gerd A2 - Sure, York A2 - Domingue, John T1 - Content Aggregation on Knowledge Bases using Graph Clustering T2 - The Semantic Web: Research and Applications PB - Springer C1 - Heidelberg PY - 2006/ CY - VL - 4011 IS - SP - 530 EP - 544 UR - http://www.kde.cs.uni-kassel.de/stumme/papers/2006/schmitz2006content.pdf DO - KW - 2006 KW - aggregation KW - clustering KW - content KW - graph KW - itegpub KW - l3s KW - myown KW - nepomuk KW - ontologies KW - ontology KW - seminar2006 KW - theory L1 - SN - N1 - N1 - AB - 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. ER - TY - CONF AU - Brandes, U. AU - Willhalm, T. A2 - T1 - Visualization of bibliographic networks with a reshaped landscape metaphor T2 - Proceedings of the symposium on Data Visualisation 2002 PB - Eurographics Association C1 - Aire-la-Ville, Switzerland, Switzerland PY - 2002/ CY - VL - IS - SP - 159 EP - ff UR - http://portal.acm.org/citation.cfm?id=509740.509765 DO - KW - bibliographic KW - bibliography KW - citation KW - graph KW - networks KW - sna L1 - SN - 1-58113-536-X N1 - Visualization of bibliographic networks with a reshaped landscape metaphor N1 - AB - We describe a novel approach to visualize bibliographic networks that facilitates the simultaneous identification of clusters (e.g., topic areas) and prominent entities (e.g., surveys or landmark papers). While employing the landscape metaphor proposed in several earlier works, we introduce new means to determine relevant parameters of the landscape. Moreover, we are able to compute prominent entities, clustering of entities, and the landscape's surface in a surprisingly simple and uniform way. The effectiveness of our network visualizations is illustrated on data from the graph drawing literature. ER - TY - CONF AU - Eklund, P. AU - Groh, B. AU - Stumme, G. AU - Wille, R. A2 - Ganter, B. A2 - Mineau, G. W. T1 - Contextual-Logic Extension of TOSCANA. T2 - Conceptual Structures: Logical, Linguistic, and Computational PB - Springer C1 - Heidelberg PY - 2000/ CY - VL - 1867 IS - SP - 453 EP - 467 UR - http://www.kde.cs.uni-kassel.de/stumme/papers/2000/ICCS_toscanaextension.pdf DO - KW - 2000 KW - analysis KW - cg KW - cgs KW - concept KW - conceptual KW - fca KW - formal KW - graph KW - graphs KW - iccs KW - myown KW - toscana L1 - SN - N1 - Publications of Gerd Stumme N1 - AB - ER - TY - CONF AU - Prediger, Susanne AU - Wille, Rudolf A2 - Tepfenhart, William M. A2 - Cyre, Walling R. T1 - The Lattice of Concept Graphs of a Relationally Scaled Context T2 - ICCS PB - Springer C1 - PY - 1999/ CY - VL - 1640 IS - SP - 401 EP - 414 UR - http://dblp.uni-trier.de/db/conf/iccs/iccs99.html#PredigerW99 DO - KW - analysis KW - cg KW - concept KW - fca KW - formal KW - graph KW - graphs L1 - SN - 3-540-66223-5 N1 - N1 - AB - ER - TY - CONF AU - Wille, Rudolf A2 - Lukose, D. A2 - Delugach, H. A2 - Keeler, M. A2 - Searle, L. A2 - Sowa, J. F. T1 - Conceptual Graphs and Formal Concept Analysis T2 - Conceptual Structures: Fulfilling Peirce's Dream PB - Springer C1 - Heidelberg PY - 1997/ CY - VL - 1257 IS - SP - 290 EP - 303 UR - DO - KW - ag1 KW - analysis KW - begriffsanalyse KW - cg KW - concept KW - conceptual KW - darmstadt KW - fba KW - fca KW - formal KW - graph KW - graphs L1 - SN - N1 - N1 - AB - ER - TY - CONF AU - Stumme, Gerd AU - Wille, Rudolf A2 - Tamassia, R. A2 - Tollis, I.G. T1 - A Geometrical Heuristic for Drawing Concept Lattices T2 - Graph Drawing PB - Springer C1 - Heidelberg PY - 1995/ CY - VL - 894 IS - SP - 452 EP - 459 UR - http://www.kde.cs.uni-kassel.de/stumme/papers/1994/P1677-GD94.pdf DO - KW - 1995 KW - analysis KW - concept KW - drawing KW - fca KW - formal KW - graph KW - lattices KW - myown L1 - SN - N1 - Publications of Gerd Stumme N1 - AB - ER -