- 页码：第106页 2013-01-06 11:15:41
As long as we thought of networks as random, we modeled them as static graphs. The scale-free model reflects our awakening to the reality that networks are dynamic systems that change constantly through the addition of new nodes and links. The fitness model allows us to describe networks as competitive systems in which nodes fight fiercely for links. Now Bose-Einstein condensation explains how some winner get the chance to take it all. Do the advances obtained by acknowledeing fitness toss out the scale-free model? By no means. In networks that display fit-get-richh behavior, competition leads to a scale-free topology. Most networks we have studies so far -- the Web, the Internet, the cell, Holloywood, and many other real networks -- belong to this category. The winner shares the spotlight with a continuous hierarchy of hubs. Yet Bose-Einstein condensation offers the theoretical possibility that in some systems the winner can grab all the links. When that happens, the scale-free topology vanishes. So far among real systems, only the operations system market, with Microsoft as its dominating hub, appears to fit the bill. Are there other systems out there displaying a similar behavior? Very likely. It will take some time, however, to recognize them all.
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