2 resultados para Ashby family (Thomas Ashby, d. 1752)

em Greenwich Academic Literature Archive - UK


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Book review of: Scarlett Thomas, PopCo, London and New York: Fourth Estate, 2004. 1-84115-763-5, £12.99.

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The paper considers an on-line single machine scheduling problem where the goal is to minimize the makespan. The jobs are partitioned into families and a setup is performed every time the machine starts processing a batch of jobs of the same family. The scheduler is aware of the number of families and knows the setup time of each family, although information about a job only becomes available when that job is released. We give a lower bound on the competitive ratio of any on-line algorithm. Moreover, for the case of two families, we provide an algorithm with a competitive ratio that achieves this lower bound. As the number of families increases, the lower bound approaches 2, and we give a simple algorithm with a competitive ratio of 2.