Harmony search for the layout design of an unequal area facility

An unequal area facility layout problem (UA-FLP) is a typical optimization problem that occurs when constructing an efficient layout within given areas. In this research, a harmony search (HS)-based heuristic algorithm is presented to solve UA-FLPs. In this study, the facility layout is represented as an allocation of blocks with restrictions in terms of an unequal area and rectangular shape. A more effective facility layout representation is proposed. This is done via a slicing tree representation as a form of layout structure, and via the HS-based algorithm, which generates a quality solution. Once the basic HS solution is generated, modifications are introduced to facilitate improvements. Specifically, the structure of the slicing tree representation is modified, and a re-adjustment operation is added to diversify the possible range of solutions. A penalty scheme is also proposed to improve the feasible region searching capabilities. The effects of the alterations are evaluated by testing well-known problems from previous studies. The proposed algorithm generates the solutions as proficiently as the best results provided by previous research. The proposed method is robust in terms of process, and it determines a favorable solution within a short amount of time.