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Approximation Algorithms for Data Management in Networks
, 2001
"... This paper deals with static data management in computer systems connected by networks. A basic functionality in these systems is the interactive ..."
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Cited by 15 (0 self)
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This paper deals with static data management in computer systems connected by networks. A basic functionality in these systems is the interactive
Modular Competitiveness for Distributed Algorithms
 In Proc. 28th ACM Symp. on Theory of Computing (STOC
, 2000
"... We define a novel measure of competitive performance for distributed algorithms based on throughput, the number of tasks that an algorithm can carry out in a fixed amount of work. This new measure complements the latency measure of Ajtai et al. [3], which measures how quickly an algorithm can finish ..."
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Cited by 13 (2 self)
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We define a novel measure of competitive performance for distributed algorithms based on throughput, the number of tasks that an algorithm can carry out in a fixed amount of work. This new measure complements the latency measure of Ajtai et al. [3], which measures how quickly an algorithm can finish tasks that start at specified times. An important property of the throughput measure is that it is modular: we define a notion of relative competitiveness with the property that a krelatively competitive implementation of an object T using a subroutine U , combined with an lcompetitive implementation of U , gives a klcompetitive algorithm for ...
A Data Tracking Scheme for General Networks
, 2001
"... Consider an arbitrary distributed network in which large numbers of objects are continuously being created, replicated, and destroyed. A basic problem arising in such an environment is that of organizing a distributed directory service for locating object copies. In this paper, we present a new data ..."
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Consider an arbitrary distributed network in which large numbers of objects are continuously being created, replicated, and destroyed. A basic problem arising in such an environment is that of organizing a distributed directory service for locating object copies. In this paper, we present a new data tracking scheme for locating nearby copies of objects in arbitrary distributed environments. Our tracking scheme supports ecient accesses to data objects while keeping the local memory overhead low. In particular, our tracking scheme achieves an expected polylog(n) approximation in the cost of any access operation, for an arbitrary network. The memory overhead incurred by our scheme is O(polylog(n)) times the maximum number of objects stored at any node, with high probability. We also show that our tracking scheme adapts well to dynamic changes in the network.
New Results for Online Page Replication
, 2003
"... We study the online page replication problem. We present a new randomized online algorithm for rings which is 2.37297competitive, improving the best previous result of 3.16396. We also show that no randomized online algorithm is better than 1.75037competitive on the ring; previously, only a 1.5819 ..."
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Cited by 6 (0 self)
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We study the online page replication problem. We present a new randomized online algorithm for rings which is 2.37297competitive, improving the best previous result of 3.16396. We also show that no randomized online algorithm is better than 1.75037competitive on the ring; previously, only a 1.58198 bound for a single edge was known. We extend the problem in several new directions: continuous metrics, variable size requests, and replication before service. This yields simplified proofs of several known results.
Competitive Analysis of Oblivious Routing on Hypercubes
, 2000
"... We study the performance of oblivious routing algorithms using competitive analysis on a d dimensional, N = 2 d node hypercube. Packets are injected into the hypercube arbitrarily and continuously, without any (e.g., probabilistic) assumption on the arrival of packets. First we consider oblivious ..."
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We study the performance of oblivious routing algorithms using competitive analysis on a d dimensional, N = 2 d node hypercube. Packets are injected into the hypercube arbitrarily and continuously, without any (e.g., probabilistic) assumption on the arrival of packets. First we consider oblivious routing algorithms that follow minimal (shortest) paths. We show that the well known deterministic oblivious routing algorithm, i.e., the greedy routing algorithm, has competitive ratio N 1=2 ). However, a randomized variant of the greedy routing algorithm is shown to be only in a factor of O(log 3 N) to our supplied problem lower bound, which is of order N log 2 (5=4) = log 5 N ), for any minimal randomized oblivious routing algorithms. The lower bound we provide is strong in that the adversaries also follow minimal paths. We do not relay on the well known fact that any permutation can be routed with constant congestion, which in general needs nonminimal paths. Next we conside...