Approximating interval scheduling problems with bounded profits

  • Authors:
  • Israel Beniaminy;Zeev Nutov;Meir Ovadia

  • Affiliations:
  • ClickSoftware Technologies;The Open University of Israel, Raanana, Israel;The Open University of Israel, Raanana, Israel

  • Venue:
  • ESA'07 Proceedings of the 15th annual European conference on Algorithms
  • Year:
  • 2007

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Abstract

We consider the Generalized Scheduling Within Intervals (GSWI) problem: given a set J of jobs and a set I of intervals, where each job j ∈ J has in interval I ∈ I length (processing time) lj,I and profit pj,I, find the highest-profit feasible schedule. The best approximation ratio known for GSWI is (1/2-Ɛ). We give a (1-1/e-Ɛ)-approximation scheme for GSWI with bounded profits, based on the work by Chuzhoy, Rabani, and Ostrovsky [4] for the {0, 1}-profit case. We also consider the Scheduling Within Intervals (SWI) problem, which is a particular case of GSWI where for every j ∈ J there is a unique interval I = Ij ∈ I with pj,I 0. We prove that SWI is (weakly) NP-hard even if the stretch factor (the maximum ratio of job's interval size to its processing time) is arbitrarily small, and give a polynomial-time algorithm for bounded profits and stretch factor