“…Viewing conceptual design as a process of coevolution of both function structures and means combinations across different levels of an abstraction hierarchy, Jin and Li [33] proposed a grammar-based hierarchical coevolutionary approach to support designers generating design concepts. Three genetic operations, namely, reproduction, crossover, and mutation of the genetic algorithm [34,35], are utilized to evaluate function structures, and their corresponding solution means. Evaluating the fitness of a given function structure is a major challenge because little quantitative information is available, although two subjective terms, feasibility, and desirability, were introduced to scale the fitness in their research.…”