LPT scheduling for fuzzy tasks

Scheduling mainly concerns allocating resources to tasks over time, under necessary constraints. In the past, the processing time for each task was usually assigned or estimated as a fixed value. In many real-world applications, however, the processing time for each job may vary dynamically with the situation. In this paper, fuzzy concepts are utilized in the LPT algorithm for managing uncertain scheduling. Given a set of tasks, each with its membership function for the processing time, the fuzzy LPT algorithm can get a scheduling result with a membership function for the final completion time. Also, the conventional LPT scheduling algorithm is shown as a special case of the fuzzy LPT scheduling algorithm with special membership functions being assigned. The fuzzy LPT scheduling algorithm is then a feasible solution for both deterministic and uncertain scheduling. (C) 1998 Elsevier Science B.V. All rights reserved.