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- George Boucek, Jeff Erickson, Jon Jonsson, Vic Riley, Marianne Rudisill
- 1995

- JEFF ERICKSON
- 1996

We present a number of new results for the combinatorial game Toads and Frogs. We begin by presenting a set of simplification rules, which allow us to split positions into independent components or replace them with easily computable numerical values. Using these simplication rules, we prove that there are Toads and Frogs positions with arbitrary numerical… (More)

We construct, for any positive integer n, a family of n congruent convex polyhedra in IR 3 , such that every pair intersects in a common facet. Our polyhedra are Voronoi regions of evenly distributed points on the helix (t, cos t, sin t). The largest previously published example of such a family contains only eight polytopes. With a simple modification, we… (More)

We survey algorithms and hardness results for two important classes of topology optimization problems: computing minimum-weight cycles in a given homotopy or homology class, and computing minimum-weight cycle bases for the fundamental group or various homology groups.

The measure problem of Klee asks for the volume of the union of n axis-parallel boxes in a fixed dimension d. We give an O(n (d+2)/3) time algorithm for the special case of all boxes being cubes or, more generally, fat boxes. Previously, the fastest run-time was n d/2 2 O(log * n) , achieved by the general case algorithm of Chan [SoCG 2008]. For the general… (More)

- Jeff Erickson
- 2002

Let Σ be a fixed smooth surface in IR 3 , such that no medial ball touches Σ more than four times, counting with multiplicity, or more than three times at any single point. We show that the Delaunay triangulation of any uniform sample of Σ has complexity O(n log n) in the worst case. We also prove that the Delaunay triangulation of n random points on Σ has… (More)

The <i>spread</i> of a finite set of points is the ratio between the longest and shortest pairwise distances. We prove that the Delaunay triangulation of any set of n points in IR<sup>3</sup> with spread Δ has complexity O(Δ<sup>3</sup>). This bound is tight in the worst case for all Δ = O(√n). In particular, the Delaunay triangulation… (More)

Is it possible to have too much information? This is a question that organizations are trying to address. In today's information-driven world, organizations have more data than ever to store, access, and retrieve. But how do organizations transform this wealth of information it into a knowledge asset and a strategic advantage? Furthermore, these knowledge… (More)

Previous research on enterprise resource planning (ERP) systems has focused mainly on the initial implementations of the solution. However, many companies that installed ERP solutions in the late 1990's are at the point where they need to upgrade their solution to a current release. This paper provides a model that identifies the different types of… (More)

- Jeff Erickson, Carmen Best, David Sumi, Bryan Ward, Bryan Zent
- 2004

This report documents a revised model for estimating emissions savings for nitrogen oxides (NOx), sulfur oxides (SOx), carbon dioxide (CO 2), and mercury (Hg) from Focus on Energy efficiency efforts. The report covers four key areas: 1. Improved yearly emissions factors for calculating emission reduction as a result of Focus on Energy activity. 2. Emission… (More)