Degree Distribution - Observed Degree Distributions

Observed Degree Distributions

The degree distribution is very important in studying both real networks, such as the Internet and social networks, and theoretical networks. The simplest network model, for example, the (Bernoulli) random graph, in which each of n nodes is connected (or not) with independent probability p (or 1 − p), has a binomial distribution of degrees:


P(k) = {n-1\choose k} p^k (1 - p)^{n-1-k},

(or Poisson in the limit of large n). Most networks in the real world, however, have degree distributions very different from this. Most are highly right-skewed, meaning that a large majority of nodes have low degree but a small number, known as "hubs", have high degree. Some networks, notably the Internet, the world wide web, and some social networks are found to have degree distributions that approximately follow a power law: P(k) ~ kγ, where γ is a constant. Such networks are called scale-free networks and have attracted particular attention for their structural and dynamical properties.

Read more about this topic:  Degree Distribution

Famous quotes containing the words observed and/or degree:

    ... the only way in which Mr. Brooke could be coerced into thinking of the right arguments at the right time was to be well plied with them till they took up all the room in his brain. But here there was the difficulty of finding room, so many things having been taken in beforehand. Mr. Brooke himself observed that his ideas stood rather in his way when he was speaking.
    George Eliot [Mary Ann (or Marian)

    Crude men who feel themselves insulted tend to assess the degree of insult as high as possible, and talk about the offense in greatly exaggerated language, only so they can revel to their heart’s content in the aroused feelings of hatred and revenge.
    Friedrich Nietzsche (1844–1900)