|   | CMU-CS-98-146 Computer Science Department
 School of Computer Science, Carnegie Mellon University
 
    
     
 CMU-CS-98-146
 
On Distributed Network Resource Allocation 
Andrea Werneck Richa 
August 1998  
Ph.D. Thesis 
CMU-CS-98-146.psCMU-CS-98-146.pdf
 Keywords: Distributed network, resource allocation, approximation
algorithm, randomized algorithm, shared object, wide-area network,
hierarchical model, expected cost, packet routing, scheduling, Lovasz 
Local Lemma, optimal schedule, network emulation, embedding, congestion, 
dilation, ordering, linear arrangement, linear array, combinatorial 
optimization, interval graph, storage-time product, spreading metric, planar graph
 This thesis addresses several resource allocation problems that arise in 
the context of distributed networks.  First, we present a scheme for
accessing shared copies of objects in a network that has asymptotically
optimal expected cost per access for a class of cost functions that
captures the hierarchical structure of most wide-area networks.  Second, we
present an off-line polynomial-time algorithm that finds an asymptotically
optimal schedule for the movement of packets whose paths through a network
have already been determined.  This is an improvement on a previous
result by Leighton, Maggs, and Rao, who proved the existance of such
schedules; their proof, however, was not constructive.  Finally we present
a polynomial-time O(log n)-approximation algorithm for finding an
embedding of a network with nprocessors into an n-node
linear array so as to minimize the weighted sum of the edge dilations --
i.e., for the minimum linear arrangement problem.  This problem is NP-hard,
and the previous best approximation bound known was O(log n log log n).
In the case of planar networks, we bring the approximation factor down to
O(log log n).  We also extend our approximation techniques to the
minimum storage-time product and the minimum containing interval graph 
problem.
 
122 pages 
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