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Unit disk graphs are the intersection graphs of equal sized circles in the plane. In this paper, we consider the maximum independent set problems on unit disk graphs. When the given unit disk graph is dened on a slab whose width is k, we propose an algorithm for nding a maximum independent set in O(n 4d2k= p 3e) time where n denotes the number of vertices.(More)
In sports timetabling, finding feasible pattern sets for a round robin tournament is a significant problem. Although this problem has been tackled in several ways, good characterization of feasible pattern sets is not known yet. In this paper, we consider the feasibility of a pattern set, and propose a necessary condition for feasible pattern sets. In the(More)
The Traveling Tournament Problem is a complex combinatorial optimization problem in tournament timetabling, which asks a schedule of home/away games meeting specific feasibility requirements , while also minimizing the total distance traveled by all the n teams (n is even). Despite intensive algorithmic research on this problem over the last decade, most(More)
Consider two orthogonal closed chains on a cylinder. The chains are monotone with respect to the angle Θ. We wish to rigidly move one chain so that the total area between the two chains is minimized. This is a geometric measure of similarity between two repeating melodies proposed by´O Maidín. We present an O(n) time algorithm to compute this measure if Θ(More)
Consider two orthogonal closed chains on a cylinder. These chains are monotone with respect to the tangential Θ direction. We wish to rigidly move one chain so that the total area between the two is minimized. This minimization is a geometric measure of similarity between two melodies proposed by´O Maidín. The Θ direction represents time and the axial(More)
A 2.75-approximation algorithm is proposed for the unconstrained traveling tournament problem, which is a variant of the traveling tournament problem. For the unconstrained traveling tournament problem, this is the first proposal of an approximation algorithm with a constant approximation ratio. In addition, the proposed algorithm yields a solution that(More)