Near-Entropy Hotlink Assignments

  • Karim Douïeb
  • Stefan Langerman
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4168)


Consider a rooted tree T of arbitrary maximum degree d representing a collection of n web pages connected via a set of links, all reachable from a source home page represented by the root of T. Each web page i carries a weight w i representative of the frequency with which it is visited. By adding hotlinks — shortcuts from a node to one of its descendents — we wish to minimize the expected number of steps l needed to visit pages from the home page, expressed as a function of the entropy H(p) of the access probabilities p. This paper introduces several new strategies for effectively assigning hotlinks in a tree. For assigning exactly one hotlink per node, our method guarantees an upper bound on l of 1.141 H(p)+1 if d>2 and 1.08 H(p)+ 2/3 if d=2. We also present the first efficient general methods for assigning at most k hotlinks per node in trees of arbitrary maximum degree, achieving bounds on l of at most \(\frac{2H(p)}{\log (k+1)}\) and \(\frac{H(p)}{\log (k+d) -- \log d}\), respectively. Finally, we present an algorithm implementing these methods in O(n logn) time, an improvement over the previous O(n 2) time algorithms.


Maximum Degree Binary Tree Original Tree Candidate Node Access Frequency 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2006

Authors and Affiliations

  • Karim Douïeb
    • 1
  • Stefan Langerman
    • 1
  1. 1.Département d’InformatiqueUniversité Libre de BruxellesBelgique

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