Community Evolution

Evolution of a particular social community can be represented as a sequence of events (changes) following each other in the successive timeframes within the temporal social network. In other words, the evolution is described by identified group transformations from time Ti to Ti+1 (i is the period index). There are several approaches to definition of possible events in the social group evolution  Asur at al. distinguish 5 possible events that may happen to groups, i.e. they may dissolve, form, continue, merge and split [Asur 07];  Pala et al. identify 6 distinct transformations: growth, contraction, merging, splitting, birth and death [Palla, 07];  Bródka at al., in turn, describe 7 noticeable event types: continuing, shrinking, growing, splitting, merging, dissolving and forming [Bródka, 12]. Some other different taxonomies can be found in [Spiliopoulou, 06], [Oliveira, 10], [Takaffoli, 11] but all of them are very similar and actually complete each other. The short description of the most common changes can be found below. Continue [Asur, 07], continuing [Bródka, 12] – the community continues its existence when two groups in the consecutive time windows are identical or when two groups differ by only few nodes but their sizes remain the same. Intuitively, continuation happens when two communities are so much similar that it is hard to see any significant differences. Community Evolution