BibSonomy publications for /user/stummeWed Mar 03 10:59:40 CET 2010NETWORKING 2005768--779Measuring Round Trip Times to Determine the Distance Between WLAN Nodes2005distance measure rfid sensor venus wlan This publication explores the degree of accuracy to which the propagation delay of WLAN packets can be measured using today’s commercial, inexpensive equipment. The aim is to determine the distance between two wireless nodes for location sensing applications. We conducted experiments in which we measured the time difference between sending a data packet and receiving the corresponding immediate acknowledgement. We found the propagation delays correlate closely with distance, having only a measurement error of a few meters. Furthermore, they are more precise than received signal strength indications. To overcome the low time resolution of the given hardware timers, various statistical methods are applied, developed and analyzed. For example, we take advantage of drifting clocks to determine propagation delays that are forty times smaller than the clocks’ quantization resolution. Our approach also determines the frequency offset between remote and local crystal clocks. ER -Mon Mar 01 23:04:36 CET 2010Washington, DC, USAIV '07: Proceedings of the 11th International Conference Information Visualization453--458Mapping Modern Science Using Co-citation Analysis2007citation cocitation kosynus research science zitationsanalyse Bibliometric analysis is used as a measuring activity technique for basic research. There are many country level analyses of trends in scientific publications. These analyses give us an understanding of the macro-scale character of scientific activities. However, it is difficult to capture the qualitative evolution of scientific activities through them. In this regard, a meso-scale analysis of science activities, i.e., analysis of "research areas", is suitable for grasping qualitative changes in scientific activities. In this study, we develop a new method for mapping science at the research area level. Our method consists of two parts: constructing research areas from scientific publications and content analysis by experts. Research areas are explored through a co-citation analysis, and a map of science was generated to analyze how research areas relate to each other. This method contributes to endeavours to understand and track the changing nature of science.Fri Feb 26 09:46:54 CET 2010Science59681018--1021Limits of Predictability in Human Mobility3272010control everyaware human mobile networking prediction privacy social venus A range of applications, from predicting the spread of human and electronic viruses to city planning and resource management in mobile communications, depend on our ability to foresee the whereabouts and mobility of individuals, raising a fundamental question: To what degree is human behavior predictable? Here we explore the limits of predictability in human dynamics by studying the mobility patterns of anonymized mobile phone users. By measuring the entropy of each individual's trajectory, we find a 93% potential predictability in user mobility across the whole user base. Despite the significant differences in the travel patterns, we find a remarkable lack of variability in predictability, which is largely independent of the distance users cover on a regular basis. Fri Feb 19 11:47:03 CET 2010Proc. 8th International Semantic Web Conference(ISWC)Live Social Semantics2009live semantics social sociopatterns venus Mon Feb 01 14:19:53 CET 2010Formal Concept Analysis22--37Concept Lattice Orbifolds – First Steps2009folding lattice orbifold sna Concept lattices with symmetries may be simplified by “folding” them along the orbits of their automorphism group. The resulting diagram is often more intuitive than the full lattice diagram, but well defined annotations are required to make the foldeddiagram as informative as the original one. The folding procedure can be extended to formal contexts.Fri Nov 27 21:23:21 CET 2009HeidelbergKI 2001: Advances in Artificial Intelligence. KI 2001335-350LNAIIntelligent Structuring and Reducing of Association Rules and with Formal Concept Analysis217420012001 FCA OntologyHandbook analysis association bases closed concept condensed discovery fca formal itemsets kdd knowledge mining myown representations rule rules Wed Nov 25 09:34:38 CET 2009cite arxiv:0811.4170 High resolution dynamical mapping of social interactions with active RFID2008rfid sociopatterns In this paper we present an experimental framework to gather data on face-to-face social interactions between individuals, with a high spatial and temporal resolution. We use active Radio Frequency Identification (RFID) devices that assess contacts with one another by exchanging low-power radio packets. When individuals wear the beacons as a badge, a persistent radio contact between the RFID devices can be used as a proxy for a social interaction between individuals. We present the results of a pilot study recently performed during a conference, and a subsequent preliminary data analysis, that provides an assessment of our method and highlights its versatility and applicability in many areas concerned with human dynamics. Mon Nov 16 10:44:04 CET 2009AachenCEUR-WSCEUR Workshop ProceedingsInformation Integration and Mining in Databases and on the Web. Proceedings of the 2nd International Workshop on Databases, Documents, and Information Fusion (DBFusion 2002)12420042004 databases dbfusion fusion information integration itegpub l3s myown proceedings web workshop Fri Nov 13 14:51:05 CET 2009New York, NY, USASSM '08: Proceeding of the 2008 ACM workshop on Search in social media67--74Efficient sampling of information in social networks2008analysis network networks sampling sna social As online social networking emerges, there has been increased interest to utilize the underlying social structure as well as the available social information to improve search. In this paper, we focus on improving the performance of information collection from the neighborhood of a user in a dynamic social network. To this end, we introduce sampling based algorithms to quickly approximate quantities of interest from the vicinity of a user's social graph. We then introduce and analyze variants of this basic scheme exploring correlations across our samples. Models of centralized and distributed social networks are considered. We show that our algorithms can be utilized to rank items in the neighborhood of a user, assuming that information for each user in the network is available. Using real and synthetic data sets, we validate the results of our analysis and demonstrate the efficiency of our algorithms in approximating quantities of interest. The methods we describe are general and can probably be easily adopted in a variety of strategies aiming to efficiently collect information from a social graph.Thu Nov 12 10:32:36 CET 2009Proc. 2008 Int. Conf. on Data Mining (ICDM'08), Pisa, Italy, Dec. 2008.December{Graph OLAP: Towards Online Analytical Processing on Graphs}2008graph graphs olap sna Tue Oct 27 16:54:56 CET 2009In Proceedings of the 23rd Annual Conference of the Cognitive Science Society611--6Testing the distributional hypothesis: The influence of context on judgements of semantic similarity2001distance distributional hypothesis measure semantic similarity tagging Distributional information has recently been implicated as playing an important role in several aspects of language ability. Learning the meaning of a word is thought to be dependent, at least in part, on exposure to the word in its linguistic contexts of use. In two experiments, we manipulated subjects ’ contextual experience with marginally familiar and nonce words. Results showed that similarity judgements involving these words were affected by the distributional properties of the contexts in which they were read. The accrual of contextual experience was simulated in a semantic space model, by successively adding larger amounts of experience in the form of item-in-context exemplars sampled from the British National Corpus. The experiments and the simulationTue Oct 27 15:12:40 CET 2009Artificial Life X480-485Strategies for fast convergence in semiotic dynamics2006agents dynamics heads semiotic semiotics talking Tue Oct 20 16:59:11 CEST 2009Enschede, The NetherlandsWorking Apart Together - Foundations For Components Groupware1998apart groupware together venus wat working Mon Oct 19 16:52:47 CEST 2009New York, NY, USAWWW '09: Proceedings of the 18th international conference on World wide web731--740Network analysis of collaboration structure in Wikipedia2009analysis collaboration network seminar2009 sna social wikipedia In this paper we give models and algorithms to describe and analyze the collaboration among authors of Wikipedia from a network analytical perspective. The edit network encodes who interacts how with whom when editing an article; it significantly extends previous network models that code author communities in Wikipedia. Several characteristics summarizing some aspects of the organization process and allowing the analyst to identify certain types of authors can be obtained from the edit network. Moreover, we propose several indicators characterizing the global network structure and methods to visualize edit networks. It is shown that the structural network indicators are correlated with quality labels of the associated Wikipedia articles.Fri Oct 16 12:37:56 CEST 2009New York, NY, USAWWW '08: Proceeding of the 17th international conference on World Wide Web915--924Planetary-scale views on a large instant-messaging network2008analysis messenger msn network seminar2009 sna social We present a study of anonymized data capturing a month of high-level communication activities within the whole of the Microsoft Messenger instant-messaging system. We examine characteristics and patterns that emerge from the collective dynamics of large numbers of people, rather than the actions and characteristics of individuals. The dataset contains summary properties of 30 billion conversations among 240 million people. From the data, we construct a communication graph with 180 million nodes and 1.3 billion undirected edges, creating the largest social network constructed and analyzed to date. We report on multiple aspects of the dataset and synthesized graph. We find that the graph is well-connected and robust to node removal. We investigate on a planetary-scale the oft-cited report that people are separated by "six degrees of separation" and find that the average path length among Messenger users is 6.6. We find that people tend to communicate more with each other when they have similar age, language, and location, and that cross-gender conversations are both more frequent and of longer duration than conversations with the same gender.Wed Oct 14 15:20:54 CEST 2009WSDM (Late Breaking-Results)conf/wsdm/2009Tagging with Queries: How and Why?2009folksonomies folksonomy logsonomies queries social tagging Fri Sep 25 22:04:14 CEST 2009Berlin, HeidelbergSocial Semantic Web18363--391X.media.pressSocial Bookmarking am Beispiel BibSonomy20092009 itegpub l3s myown tagorapub BibSonomy ist ein kooperatives Verschlagwortungssystem (Social Bookmarking System), betrieben vom Fachgebiet Wissensverarbeitung der Universit{\"a}t Kassel. Es erlaubt das Speichern und Organisieren von Web-Lesezeichen und Metadaten für wissenschaftlichePublikationen. In diesem Beitrag beschreiben wir die von BibSonomy bereitgestellte Funktionalit{\"a}t, 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.Fri Sep 25 22:01:05 CEST 2009Bled, SloveniaProceedings of the 1st Workshop on Explorative Analytics of Information Networks (EIN2009)SeptemberCharacterizing Semantic Relatedness of Search Query Terms20092009 ecml l3s logsonomies measures myown pkdd relatedness semantic similarity Fri Sep 25 21:59:24 CEST 2009Workshop on Knowledge Discovery, Data Mining, and Machine Learningsep44 --51Testing and Evaluating Tag Recommenders in a Live System20092009 bibsonomy ecml l3s myown pkdd recommender tagging The challenge to provide tag recommendations for collaborative tagging systems has attracted quite some attention of researchers lately. However, most research focused on evaluation and development of appropriate methods rather than tackling the practical challenges of how to integrate recommendation methods into real tagging systems, record and evaluate their performance. In this paper we describe the tag recommendation framework we developed for our social bookmark and publication sharing system BibSonomy. With the intention to develop, test, and evaluate recommendation algorithms and supporting cooperation with researchers, we designed the framework to be easily extensible, open for a variety of methods, and usable independent from BibSonomy. Furthermore, this paper presents an evaluation of two exemplarily deployed recommendation methods, demonstrating the power of the framework.Fri Sep 25 21:58:12 CEST 2009New York, NY, USAHT '09: Proceedings of the 20th ACM Conference on Hypertext and Hypermediajun323--324Managing publications and bookmarks with BibSonomy20092009 bibsonomy ht09 l3s myown In this demo we present BibSonomy, a social bookmark and publication sharing system.