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From: mwang@watmath.UUCP (mwang)
Newsgroups: ont.events
Subject: UW Essay Presentation, Miss Mao on ``Reorganization Heuristics for Search Trees  with Uniform Access Frequencies''.
Message-ID: <15752@watmath.UUCP>
Date: Mon, 15-Jul-85 14:59:44 EDT
Article-I.D.: watmath.15752
Posted: Mon Jul 15 14:59:44 1985
Date-Received: Wed, 17-Jul-85 03:13:38 EDT
Expires: Thu, 18-Jul-85 00:00:00 EDT
Organization: U of Waterloo, Ontario
Lines: 38








         DEPARTMENT OF COMPUTER SCIENCE
         UNIVERSITY OF WATERLOO
         SEMINAR ACTIVITIES

         ESSAY PRESENTATION

                             - Wednesday, July 17, 1985.

         Miss  Shya-yun  Mao of the Computer Science Department,
         will  speak  on  ``Reorganization Heuristics for Search
         Trees with Uniform Access Frequencies.''

         TIME:                2:30 PM

         ROOM:              MC 6091A

         ABSTRACT

         This talk explores the performance of different heuris-
         tic  rules  for  dynamically reorganizing binary search
         trees under the assumption that every node has the same
         access  probability, Three algorithms are presented and
         analyzed.   Two of these shift the accessed node to the
         root;  the  third  one  shifts  it  up  one level.  The
         results  show  that  moving the node to the root is the
         best  heuristic rule.  The ``simple'' move-to-root rule
         does  not affect the probability distribution of trees,
         but the other two result in a worse probability distri-
         bution.   The  effect of partial shifts between the ac-
         cessed  node and the root is also discussed; the ``sim-
         ple'' move-to-root rule is still the best heuristic.