A case for end system multicast (keynote address)
Proceedings of the 2000 ACM SIGMETRICS international conference on Measurement and modeling of computer systems
Design of a multi-sender 3D videoconferencing application over an end system multicast protocol
MULTIMEDIA '03 Proceedings of the eleventh ACM international conference on Multimedia
End system multicast protocol for collaborative virtual environments
Presence: Teleoperators and Virtual Environments - Special issue: Advances in collaborative virtual environments
Local heuristics and the emergence of spanning subgraphs in complex networks
Theoretical Computer Science - Complex networks
Playing push vs pull: models and algorithms for disseminating dynamic data in networks
Proceedings of the eighteenth annual ACM symposium on Parallelism in algorithms and architectures
Approximation algorithms for spanner problems and Directed Steiner Forest
Information and Computation
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A k-spanner of a connected (undirected unweighted) graph G=(V,E) is a subgraph G' consisting of all the vertices of V and a subset of the edges, with the additional property that the distance between any two vertices in G' is larger than that distance in G by no more than a factor of k. This paper is concerned with approximating the problem of finding a 2-spanner in a given graph, with minimum maximum degree. We first show that the problem is at least as hard to approximate as set cover. Then a randomized approximation algorithm is provided for this problem, with approximation ratio of $\tilde O(\Delta^{1/4})$. We then present a probabilistic algorithm that is more efficient for sparse graphs. Our algorithms are converted into deterministic ones using derandomization.