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					IEEE Intelligent Systems, Special Issue on Social Learning, 2010   1
 Goal: analyzing how the networks evolve
                over time
• Models of social networks
  – networks follow power-law degree distribution,
  – have a small diameter
  – exhibit small-world structure and community structure
• Social networks is a function of time
  – The Obama network
• Various Models have been studied
  – many tools have been built (example)



                                                            2
           Dynamic Models
• The preferential attachment model:
  – assumes that new network nodes have a
    higher probability of forming links with high-
    degree nodes
  – creating a “rich-get-richer” effect


                       Network diameter
                       shrinks over time
                         From: Leskovec et al. KDD’05
                                                        3
  Questions raised in this paper
• Studying network formation strategies
  – Microscopic level
• Graph Evolution Rules
  – Association rules
  – From current network configurations
     • Predict future edges and nodes
• Rules
  – Old-old
  – Old-new
  – New-new

                                          4
      Co-authorship Network
• http://www.arnetminer.org/viewperson.do?i
  d=486660&name=Qiang%20Yang
• http://academic.research.microsoft.com/Vi
  sualExplorer#435931




                                          5
     Basic Concepts: Frequent Patterns
     and Association Rules (from J. Han)

Transaction-id           Items bought      • Itemset X={x1, …, xk}
     10                     A, B, C        • Find all the rules XY with min
     20                      A, C            confidence and support
     30                      A, D             – support, s, probability Pr(X,Y)
     40                     B, E, F           – confidence, c, conditional
                                                probability Pr(Y|X).
             Customer        Customer
             buys both       buys diaper
                                               Let min_support = 50%,
                                               min_conf = 50%:
                                                  A  C (50%, 66.7%)
                                                  C  A (50%, 100%)
 Customer
 buys beer
                                                                            6
  Association Rules on Graphs
• First, we need to record
  time stamps on graphs
  – Nodes
  – Edges
     • A large-degree node (label 3),
       which at time t is connected to
       four medium-degree nodes
       (label 2), at time t +1 will be
       connected to a fifth node.
  – The collaboration-rich
    researcher gets richer.

                                         7
G-span based GER Algorithm




                             8
Example GER Rules




                    9
Too many rules? Ranking




                          10
Datasets




           11
Precision-Recall Curve




                         12
Dataset Statistics




                     13
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posted:8/18/2011
language:English
pages:15