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Rescooped by Miguel_delF from Social Network Analysis - Critique
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FBI lobbying US government for 'back doors' into Facebook, Google and Skype

FBI lobbying US government for 'back doors' into Facebook, Google and Skype | SNA | Scoop.it

US spooks call for easier wiretapping of social media – and heavy punishments for companies that don't comply (FBI lobbying US government for 'back doors' into #Facebook, #Google and #Skype http://t.co/LGoRxgRZ8x...


Via Steven McDermott
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Rescooped by Miguel_delF from Social Network Analysis
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Modularity and community structure in networks


Via luiy, Pablo Torres
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luiy's curator insight, May 10, 2013 9:25 AM

Many networks of interest in the sciences, including a variety of social and biological networks, are found to divide naturally into communities or modules. The problem of detecting and characterizing this community structure has attracted considerable recent attention. One of the most sensitive detection methods is optimization of the quality function known as “modularity” over the possible divisions of a network, but direct application of this method using, for instance, simulated annealing is computationally costly. Here we show that the modularity can be reformulated in terms of the eigenvectors of a new characteristic matrix for the network, which we call the modularity matrix, and that this reformulation leads to a spectral algorithm for community detection that returns results of better quality than competing methods in noticeably shorter running times. We demonstrate the algorithm with applications to several network data sets.

 

 

Example applications


In practice, the algorithm developed here gives excellent results. For a quantitative comparison between our algorithm and others we follow Duch and Arenas [19] and compare values of the modularity for a variety of
networks drawn from the literature. Results are shown in Table I for six different networks—the exact same six as used by Duch and Arenas. We compare modularity figures against three previously published algorithms: the betweenness-based algorithm of Girvan and Newman [10], which is widely used and has been incorporated into some of the more popular network analysis programs (denoted GN in the table); the fast algorithm of Clauset et al. [26] (CNM), which optimizes modularity using a greedy algorithm; and the extremal optimization algorithm of Duch and Arenas [19] (DA), which is arguably the best previously existing method, by standard
measures, if one discounts methods impractical for large networks, such as exhaustive enumeration of all partitions or simulated annealing.

Rescooped by Miguel_delF from Comunicación 360º. Comunicating Today
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Análisis de redes sociales para comunicación, marketing y relaciones públicas

Análisis de redes sociales para comunicación, marketing y relaciones públicas | SNA | Scoop.it

"Los investigadores en Análisis de Redes Sociales (ARS) o Social Network Analysis (SNA) -desde las matemáticas, la física y las ciencias computacionales- han aportado conceptos y métricas para el estudio sistemático de procesos sociales impensables hace unos años para científicos sociales y, también en gran medida, es cuestión de que los responsables de departamentos de comunicación, marketing y relaciones públicas asuman estas líneas de trabajo como algo que hoy es posible y que sólo hace unos años podía ser considerado como ciencia ficción."


Via Grupo Comunicating
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Rescooped by Miguel_delF from Social Network Analysis - Critique
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Social Networks or Anti-Social Surveillance Networks? | Endless Innovation | Big Think

Social Networks or Anti-Social Surveillance Networks? | Endless Innovation | Big Think | SNA | Scoop.it

We typically focus on the positive aspects of online social networks - but what about their negative aspects?


Via Steven McDermott
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La Física de lo Social - Meditaciones Sociológicas

La Física de lo Social - Meditaciones Sociológicas | SNA | Scoop.it
Palabras claves. Número de papers para ese topic. Número de citas. Social. 590. 1.089. Social Networks. 406. 821. Social Dynamics. 325. 654. Social Analysis. 138. 218. Sociology. 10. 15 ...
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