For instance, researchers used the algorithm to sort books sold on Amazon.com into left- and right-wing groups, and they found the book most appealing to conservatives was actually written by Democrat Zell Miller.
Miller, the former governor of Georgia and U.S. senator, angered Democrats by endorsing George Bush during the last presidential election. Miller's book, "A National Party No More, The Conscience of a Conservative Democrat," was the book most central to the community of conservative book buyers, according to researchers.
A network is a system of nodes connected by links and the nodes sometimes divide into groups or communities, said U-M physics associate professor Mark Newman, who developed the technique. By analyzing these groups, scientists better understand the structure and function of the network. Although methods for detecting groupings in networks have been proposed before, the U-M technique performs it faster and more accurate than other methods, Newman said. It also adds a new element to the analysis: it weighs how tightly members are bound to their groups, which can affect their functions or the roles that they play.
In the example of political books, Newman looked at 105 political titles recently sold on Amazon.com. The network was compiled by Valdis Krebs, a management consultant friend of Newman's, who looked up each book and noted which books were commonly purchased by the same buyers---information that Amazon includes on its website. The links in the network represent purchasing connections between books.
When analyzed using Newman's method, the network of books separated into four communities, with dense connections within communities and looser connections betw
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Contact: Laura Bailey
baileylm@umich.edu
734-647-7087
University of Michigan
24-May-2006