Birkholz, J. M.; Bakhshi, R.; Harige, R.; van Steen, M. & Groenewegen, P.: Scalable Analysis of Socially Informed Network Models: the data-aware mean-field approach . In: CoRR abs/1209.6615 (2012),
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Studies on social networks have proved that endogenous and exogenous factors influence dynamics. Two streams of modeling exist on explaining the dynamics of social networks: 1) models predicting links through network properties, and 2) models considering the effects of social attributes. In this interdisciplinary study we work to overcome a number of computational limitations within these current models. We employ a mean-field model which allows for the construction of a population-specific socially informed model for predicting links from both network and social properties in large social networks. The model is tested on a population of conference coauthorship behavior, considering a number of parameters from available Web data. We address how large social networks can be modeled preserving both network and social parameters. We prove that the mean-field model, using a data-aware approach, allows us to overcome computational burdens and thus scalability issues in modeling large social networks in terms of both network and social parameters. Additionally, we confirm that large social networks evolve through both network and social-selection decisions; asserting that the dynamics of networks cannot singly be studied from a single perspective but must consider effects of social parameters.

Leydesdorff, L.: Alternatives to the Journal Impact Factor: I3 and the Top-10% (or Top-25%?) of the Most-Highly Cited Papers. In: Digital Libraries 1201.4638 (2012),
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Journal Impact Factors (IFs) can be considered historically as the first attempt to normalize citation distributions by using averages over two years. However, it has been recognized that citation distributions vary among fields of science and that one needs to normalize for this. Furthermore, the mean-or any central-tendency statistics-is not a good representation of the citation distribution because these distributions are skewed. Important steps have been taken to solve these two problems during the last few years. First, one can normalize at the article level using the citing audience as the reference set. Second, one can use non-parametric statistics for testing the significance of differences among ratings. A proportion of most-highly cited papers (the top-10% or top-quartile) on the basis of fractional counting of the citations may provide an alternative to the current IF. This indicator is intuitively simple, allows for statistical testing, and accords with the state of the art.

Pfaltz, J. L.: Entropy in Social Networks. Proceedings of the SOCINFO. 2012

We introduce the concepts of closed sets and closure operators as mathematical tools for the study of social networks. Dynamic networks are represented by transformations. It is shown that under continuous change/transformation, all networks tend to "break down" and become less complex. It is a kind of entropy. The product of this theoretical decomposition is an abundance of triadically closed clusters which sociologists have observed in practice. This gives credence to the relevance of this kind of mathematical analysis in the sociological context.

Evans, B. M.; Kairam, S. & Pirolli, P.: Do your friends make you smarter?: An analysis of social strategies in online information seeking. In: Information Processing & Management 46 (2010), Nr. 6, S. 679-692
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Prior research in the social search space has focused on the informational benefits of collaborating with others during web and workplace information seeking. However, social interactions, especially during complex tasks, can have cognitive benefits as well. Our goal in this paper is to document the methods and outcomes of using social resources to help with exploratory search tasks. We used a talk-aloud protocol and video capture to explore the actions of eight subjects as they completed two ''Google-hard'' search tasks. Task questions were alternated between a Social and Non-Social Condition. The Social Condition restricted participants to use only social resources-search engines were not allowed. The Non-Social Condition permitted normal web-based information sources, but restricted the use of social tools. We describe the social tactics our participants used in their search process. Asking questions on social networking sites and targeting friends one-on-one both resulted in increased information processing but during different phases of the question-answering process. Participants received more responses via social networking sites but more thorough answers in private channels (one-on-one). We discuss the possibility that the technological and cultural affordances of different social-informational media may provide complementary cognitive benefits to searchers. Our work suggests that online social tools could be better integrated with each other and with existing search facilities. We conclude with a discussion of our findings and implications for the design of social search tools.

Bollen, J.; van de Sompel, H.; Hagberg, A.; Bettencourt, L.; Chute, R.; Rodriguez, M. A. & Balakireva, L.: Clickstream Data Yields High-Resolution Maps of Science. In: PLoS ONE 4 (2009), Nr. 3, S. e4803
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Background Intricate maps of science have been created from citation data to visualize the structure of scientific activity. However, most scientific publications are now accessed online. Scholarly web portals record detailed log data at a scale that exceeds the number of all existing citations combined. Such log data is recorded immediately upon publication and keeps track of the sequences of user requests (clickstreams) that are issued by a variety of users across many different domains. Given these advantages of log datasets over citation data, we investigate whether they can produce high-resolution, more current maps of science. Methodology Over the course of 2007 and 2008, we collected nearly 1 billion user interactions recorded by the scholarly web portals of some of the most significant publishers, aggregators and institutional consortia. The resulting reference data set covers a significant part of world-wide use of scholarly web portals in 2006, and provides a balanced coverage of the humanities, social sciences, and natural sciences. A journal clickstream model, i.e. a first-order Markov chain, was extracted from the sequences of user interactions in the logs. The clickstream model was validated by comparing it to the Getty Research Institute's Architecture and Art Thesaurus. The resulting model was visualized as a journal network that outlines the relationships between various scientific domains and clarifies the connection of the social sciences and humanities to the natural sciences. Conclusions Maps of science resulting from large-scale clickstream data provide a detailed, contemporary view of scientific activity and correct the underrepresentation of the social sciences and humanities that is commonly found in citation data.

Desikan, P. K.; Pathak, N.; Srivastava, J. & Kumar, V.: Divide and conquer approach for efficient pagerank computation. ICWE '06: Proceedings of the 6th international conference on Web engineering. New York, NY, USA: ACM Press, 2006, S. 233-240
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Alvarez-Hamelin, J. I.; Dall'Asta, L.; Barrat, A. & Vespignani, A.: k-core decomposition: a tool for the analysis of large scale Internet graphs. , 2005
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Koch, J. H.: Unterstützung der Formierung und Analyse von virtuellen Communities. Frankfurt am Main: Peter Lang Publishing Group, 2003 (Europäische Hochschulschriften 41)

Systeme, die den Informationsaustausch in Communities unterstützen, sind heute allgegenwärtig. Eine zielgerichtete Analyse solcher Communities ist allerdings nur schwer möglich, denn es gibt bislang kein Verfahren zur formalen Beschreibung virtueller Communities, auf dem aufbauend eine Analyse stattfinden könnte. Es wird ein Konzept vorgestellt, das die Brücke schlägt zwischen den natürlichsprachlichen Beschreibungen von virtuellen Communities in der Soziologie und der Psychologie, und einer formalen Beschreibung, wie sie für die zielgerichtete Software-Entwicklung nötig ist. Neben einem formalen Modell von virtuellen Communities wird ein komponentenbasierter Ansatz vorgestellt, der beschreibt, wie mit diesem Modell gezielt Unterstützungs- und Analysesysteme entwickelt werden können.