Theoretical Aspect—A Formal Definition

Abstract

Along with the continuous developments in hyper-heuristic (HH), various descriptive definitions for HH have emerged, leading to classifications of HH. Initially, hyper-heuristics have been defined as a search technique “to decide (select) at a higher abstraction level which low-level heuristics to apply” [51], “to combine simple heuristics” [162], or recently as a search method or learning mechanism for selecting or generating heuristics to solve computational search problems [30]. HH is thus categorized into four classifications, namely, selection perturbative / constructive, generation perturbative / constructive (see Chapters 3, 2, 5 and 4). Some attempts have also been made to generalize these classifications of HH, to allow both selection / generation and offline / online learning to interoperate within a repository [180]. It has also been proposed that the “domain barrier” in the HH definition should be moved so more knowledge can be easily incorporated in a more expressive HH for inexperienced practitioners [179].