Dynamic Royal Road Function
Used in: [FMRR08][PCR08][YWW+08][YT08]
Royal road functions (Mitchell, Forrest, and Holland, 1992) constitute a class of fitness landscapes. A royal road function is defined in terms of various landscape features; for this purpose, a schema tree is typically used, where a block size and a block length must be defined. The difficulty of these functions rely on the formation of plateaus in the fitness landscape.
The fitness of a binary string x is defined as:
ƒ(x) = ∑s ∈ S csσs(x)
where cs is the value assigned to schema s and σs(x) is 1 if x is an instance of schema s, 0 otherwise.
The dynamic problem can be defined as a generalization of the static one, where the schemas change over time.
ƒ(x, t) = ∑s ∈ S csσs(x, t)
The severity can be controlled with the degree of changed bits in each schema.