Monthly Archives: September 2015

“Maintaining the Duality of Closeness and Betweenness Centrality”

Ulrik Brandes, Stephen Borgatti, and Linton Freeman have an interesting paper in the latest volume of Social Networks: “Maintaining the Duality of Closeness and Betweenness Centrality.” Here’s the abstract:

Betweenness centrality is generally regarded as a measure of others’ dependence on a given node, and therefore as a measure of potential control. Closeness centrality is usually interpreted either as a measure of access efficiency or of independence from potential control by intermediaries. Betweenness and closeness are commonly assumed to be related for two reasons: first, because of their conceptual duality with respect to dependency, and second, because both are defined in terms of shortest paths. We show that the first of these ideas – the duality – is not only true in a general conceptual sense but also in precise mathematical terms. This becomes apparent when the two indices are expressed in terms of a shared dyadic dependency relation. We also show that the second idea – the shortest paths – is false because it is not preserved when the indices are generalized using the standard definition of shortest paths in valued graphs. This unveils that closeness-as-independence is in fact different from closeness-as-efficiency, and we propose a variant notion of distance that maintains the duality of closeness-as-independence with betweenness also on valued relations.

Ulrik Brandes, Stephen P. Borgatti, and Linton C. Freeman, “Maintaining the Duality of Closeness and Betweenness Centrality,” Social Networks 44 (2016): 153-159.

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New: List of English Personal Nouns

I’ve put together a list of English nouns that refer to people (or, less clunkily, “personal nouns”). I plan to use it alongside existing text analysis tools (like David Bamman’s excellent BookNLP) to detect unnamed characters in the Gospels and other ancient biography. It should also, hopefully, make automatic social network extraction easier and more accurate.

The list, along with the code and sources I used to generate it, is available on my GitHub.

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