Scatter Search based algorithms for min-max regret task scheduling problems with interval uncertainty

Uncertain versions of three task scheduling problems: P║C_max, F2║C_max, R║Σ C_j are investigated. Parametric uncertainty is only considered which is represented by intervals. It is assumed that values of execution times of tasks are not a priori given, and they belong to the intervals of known bounds. No distributions additionally characterizing the uncertain parameters are assumed. The regret is used as the basis for a criterion evaluating the uncertainty. In a consequence, min-max regret combinatorial problems are solved. Heuristic algorithms based on Scatter Search are proposed. They are evaluated via computational experiments and compared to a simple middle intervals heuristics and to exact solutions for small instances of the problems considered.