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The classical Steiner tree problem in weighted graphs seeks a minimum weight connected subgraph containing a given subset of the vertices (terminals). We present a new polynomial-time heuristic that achieves a best-known approximation ratio of 1 + ln 3 2 ≈ 1.55 for general graphs, and best-known approximation ratios of ≈ 1.28 for quasi-bipartite graphs(More)
We propose a provably good performance-driven global routing algorithm for both cell-based and building-block design. The approach is based on a new bounded-radius minimum routing tree formulation. We first present several heuris-tics with good performance, based on an analog of Prim's minimum spanning tree construction. Next, we give an algorithm which(More)
We present critical-sink routing tree (CSRT) constructions which exploit available critical-path information to yield high-performance routing trees. Our CS-Steiner and "global slack removal" algorithms together modify traditional Steiner tree constructions to optimize signal delay at identified critical sinks. We further propose an iterative Elmore routing(More)
Previous literature on the Traveling Salesman Problem (TSP) assumed that the sites to be visited are stationary. Motivated by practical applications, we introduce a time-dependent generalization of TSP which we call Moving-Target TSP, where a pursuer must intercept in minimum time a set of targets which move with constant velocities. We propose approximate(More)
The minimum rectilinear Steiner tree (MRST) problem is very important for such aspects of physical layout as global routing and wiring estimation. Virtually all previous heuristics for computing rectilinear Steiner trees begin with a minimum spanning tree (MST) topology and rearrange edges to induce Steiner points. This paper gives a more direct approach(More)
Motivated by the goal of increasing the performance of FPGA-based designs, we propose effective Steiner and arborescence FPGA routing algorithms. Our graph-based Steiner tree constructions have provably-good performance bounds and outperform the best known ones in practice, while our arborescence heuristics produce routing solutions with optimal source-sink(More)
In this paper we address the problem of primer selection in polymerase chain reaction (PCR) experiments. We prove that the problem of minimizing the number of primers required to amplify a set of DNA sequences is NP-complete. Moreover, we show that it is also intractable to approximate solutions to this problem to within a constant times optimal. On the(More)