Kenneth D. Boese

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We analyze relationships among local minima for the traveling salesman and graph bisection problems under standard neighborhood structures. Our work reveals surprising correlations that suggest a globally convex, or \big valley" structure in these optimization cost surfaces. In conjunction with combinatorial results that sharpen previous analyses, our(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)
This paper studies the distribution of good solutions for the traveling salesman problem (TSP) on a well-known 532-city instance that has been solved optimally by Padberg and Rinaldi 16]. For each of ve local search heuristics, solutions are obtained from 2,500 diierent random starting points. Comparisons of these solutions show that lower-cost solutions(More)
We address the eecient construction of interconnection trees with near-optimal delay properties. Our study begins from rst principles: we consider the accuracy and delity of easily-computed delay models (speciically, Elmore delay) with respect to the delay values computed from detailed simulation of underlying physical phenomena (e.g., SPICE simulator(More)
We provide a new theoretical framework for constructing Steiner routing trees with minimum Elmore delay. Earlier work [3, 13] has established Elmore delay as a high fidelity estimate of "physical", i.e., SPICE-computed, signal delay. Previously, however, it was not known how to construct an Elmore delay-optimal Steiner tree. Our main theoretical result is a(More)
We present two critical-sink routing tree (CSRT) constructions which exploit critical-path information that becomes available during timing-driven layout. Our CS-Steiner heuristics with "Global Slack Removal" modify traditional Steiner constructions and produce routing trees with significantly lower critical-sink delays compared with existing(More)
We present new methods for scan chain ordering under the minimum wirelength objective. We have adapted the standard 2-opt and 3-opt heuristics for the symmetric traveling salesman problem (TSP) to scan chain ordering, which can be formulated as an asymmetric TSP. We show that our method is superior to a previous approach, which transformed the scan chain(More)