The group Steiner tree problem is a generalization of the Steiner tree problem where we are given several subsets (groups) of vertices in a weighted graph, and the goal is to find a minimum-weight connected subgraph containing at least one vertex from each group. The problem was introduced by Reich and Widmayer and linds applications in VLSI design. The… (More)
Given a nite set of \red" elements R, a nite set of \blue" elements B and a family S 2 RB , the red-blue set cover problem is to nd a subfamily C S which covers all blue elements, but which covers the minimum possible number of red elements. We note that Red-Blue Set Cover is closely related to several combinatorial optimization problems studied earlier.… (More)
Network-on-chip (NoC) has been proposed as a solution for the communication challenges of System-on-chip (SoC) design in the nanoscale regime. SoC design offers the opportunity for incorporating custom NoC architectures that are more suitable for a particular application, and do not necessarily conform to regular topologies. This paper presents novel linear… (More)
We present simple semi-definite programming relaxations for the NP-hard minimum bandwidth and minimum length linear ordering problems. We then show how these relaxations can be rounded in a natural way (via random projection) to obtain new approximation guarantees for both of these vertex-ordering problems.
We describe and analyze empirically an implementation of some generalizations of Dijkstra's algorithm for shortest paths in graphs. The implementation formed a part of the TRANSIMS project at the Los Alamos National Laboratory. Besides offering the first implementation of the shortest path algorithm with regular language constraints, our code also solves… (More)
Network-on-chip (NoC) has been proposed as a solution to the communication challenges of system-on-chip (SoC) design in nanoscale technologies. Application specific SoC design offers the opportunity for incorporating custom NoC architectures that are more suitable for a particular application, and do not necessarily conform to regular topologies. Custom NoC… (More)
We study ways to restrict or prevent the damage that can be caused in a peer-to-peer network by corrupt entities creating multiple pseudonyms. We show that it is possible to <i>remotely</i> issue certificates that can be used to test the distinctness of identities. To our knowledge, this is the first work that shows that remote anonymous certification of… (More)