Approximation algorithms for geometric median problems
Information Processing Letters
A primal-dual approximation algorithm for generalized Steiner network problems
STOC '93 Proceedings of the twenty-fifth annual ACM symposium on Theory of computing
Approximation algorithms for facility location problems (extended abstract)
STOC '97 Proceedings of the twenty-ninth annual ACM symposium on Theory of computing
Rounding via trees: deterministic approximation algorithms for group Steiner trees and k-median
STOC '98 Proceedings of the thirtieth annual ACM symposium on Theory of computing
Generating Low-Degree 2-Spanners
SIAM Journal on Computing
A constant-factor approximation algorithm for the k-median problem (extended abstract)
STOC '99 Proceedings of the thirty-first annual ACM symposium on Theory of computing
Design networks with bounded pairwise distance
STOC '99 Proceedings of the thirty-first annual ACM symposium on Theory of computing
Greedy strikes back: improved facility location algorithms
Journal of Algorithms
Cooperative facility location games
SODA '00 Proceedings of the eleventh annual ACM-SIAM symposium on Discrete algorithms
K-medians, facility location, and the Chernoff-Wald bound
SODA '00 Proceedings of the eleventh annual ACM-SIAM symposium on Discrete algorithms
Computers and Intractability: A Guide to the Theory of NP-Completeness
Computers and Intractability: A Guide to the Theory of NP-Completeness
An Improved Approximation Algorithm for the Metric Uncapacitated Facility Location Problem
Proceedings of the 9th International IPCO Conference on Integer Programming and Combinatorial Optimization
Approximation Hardness of the Steiner Tree Problem on Graphs
SWAT '02 Proceedings of the 8th Scandinavian Workshop on Algorithm Theory
Primal-Dual Algorithms for Connected Facility Location Problems
APPROX '02 Proceedings of the 5th International Workshop on Approximation Algorithms for Combinatorial Optimization
Beyond Steiner's Problem: A VLSI Oriented Generalization
WG '89 Proceedings of the 15th International Workshop on Graph-Theoretic Concepts in Computer Science
A tight bound on approximating arbitrary metrics by tree metrics
Proceedings of the thirty-fifth annual ACM symposium on Theory of computing
Primal-Dual Approximation Algorithms for Metric Facility Location and k-Median Problems
FOCS '99 Proceedings of the 40th Annual Symposium on Foundations of Computer Science
Probabilistic approximation of metric spaces and its algorithmic applications
FOCS '96 Proceedings of the 37th Annual Symposium on Foundations of Computer Science
Multicommodity facility location
SODA '04 Proceedings of the fifteenth annual ACM-SIAM symposium on Discrete algorithms
Combs, needles, haystacks: balancing push and pull for discovery in large-scale sensor networks
SenSys '04 Proceedings of the 2nd international conference on Embedded networked sensor systems
FeedTree: sharing web micronews with peer-to-peer event notification
IPTPS'05 Proceedings of the 4th international conference on Peer-to-Peer Systems
Multicommodity facility location under group Steiner access cost
Proceedings of the twenty-second annual ACM-SIAM symposium on Discrete Algorithms
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Consider a network in which a collection of source nodes maintain and periodically update data objects for a collection of sink nodes, each of which periodically accesses the data originating from some specified subset of the source nodes. We consider the task of efficiently relaying the dynamically changing data objects to the sinks from their sources of interest. Our focus is on the following "push-pull" approach for this data dissemination problem. Whenever a data object is updated, its source relays the update to a designated subset of nodes, its push set; similarly, whenever a sink requires an update, it propagates its query to a designated subset of nodes, its pull set. The push and pull sets need to be chosen such that every pull set of a sink intersects the push sets of all its sources of interest. We study the problem of choosing push sets and pull sets to minimize total global communication while satisfying all communication requirements.We formulate and study several variants of the above data dissemination problem, that take into account different paradigms for routing between sources (resp., sinks) and their push sets (resp., pull sets) -- multicast, unicast, and controlled broadcast -- as well as the aggregability of the data objects. Under the multicast model, we present an optimal polynomial time algorithm for tree networks, which yields a randomized O(log n)-approximation algorithm for n-node general networks, for which the problem is hard to approximate within a constant factor. Under the unicast model, we present a randomized O(log n)-approximation algorithm for non-metric costs and a matching hardness result. For metric costs, we present an O(1)-approximation and matching hardness result for the case where the interests of any two sinks are either disjoint or identical. Finally, under the controlled broadcast model, we present optimal polynomial-time algorithms.While our optimization problems have been formulated in the context of data communication in networks, our problems also have applications to network design and multicommodity facility location and are of independent interest.