Comparing node degrees in probabilistic networks
Abstract Degree is a fundamental property of nodes in networks. However, computing the degree distribution of nodes in probabilistic networks is an expensive task for large networks. To overcome this difficulty, expected degree is commonly utilized in the literature. However, in this article, we show that in some cases expected degree does not allow us to evaluate the probability of two nodes having the same degree or one node having higher degree than another. This suggests that expected degree in probabilistic networks does not completely play the same role as degree in deterministic networks. For each node, we define a reference node with the same expected degree but the least possible variance, corresponding to the least uncertain degree distribution. Then, we show how the probability of a node’s degree being higher or equal to the degree of its reference node can be approximated by using variance and skewness of the degree distribution in addition to expected degree. Experimental results on a real dataset show that our approximation functions produce accurate probability estimations in linear computational complexity, while computing exact probabilities is polynomial with order of 3.