Overcoming Representation Issues when Including Aesthetic Criteria in Evolutionary Design

Abstract

It is well known that for any sort of evolutionary search we must represent the problem solution in a suitable manner since the choice of representation has a large impact on the type and efficiency of the evolutionary search procedure applied. Usually in evolutionary design applications either bit strings or real number parameters are used to encode the problem. However, during the initial design phase a 'design' may not be decomposable into real number parameters since the nature of the search space is not well understood and / or the designer wishes to maintain a highly flexible approach whilst establishing an initial configuration. The paper introduces the overall objectives of the project and discusses representation issues before presenting an object-based representation which tries to incorporate the ambiguity present during the initial design phase by working with design elements and objects as members of the chromosome. Ambiguity is particularly acute in this case as the overall project objective is the development of a user-centric evolutionary design system that includes aesthetic criteria evaluation.

Multi-objective analysis of a component-based representation within an interactive evolutionary design system

“…keeping a check on potentially disruptive processes and repairing the structure, where necessary, to ensure feasibility. For further details of the representation, evolutionary processes and C.A.R.A., the reader is referred to works by Machwe et al (2005aMachwe et al ( , 2005b and Machwe and Parmee (2006).…”

“…The inclusion of all the above features within an interactive evolutionary framework makes the IEDS for bridge design unique. For further details of the Bridge Design system the reader is directed to Machwe et al (2005aMachwe et al ( , 2005b.…”

“…Aesthetic fitness is assessed via the subjective judgment of the user combined with a simple machine-based aesthetic rule set, whereas structural aspects are evaluated using machine-based analysis. Previous articles (Machwe et al 2005a, 2005b, Machwe and Parmee 2006 have described, in detail, the development of the main system components and the utilization of two test application areas. Although these areas are relatively simple in representation terms, they possess the required characteristics to support our primary objective, i.e.…”

“…Figure 1 describes the interactive Bridge Design system (hereafter referred to as the Bridge Design system) used in this study. The novel aspects of the Bridge Design system (Machwe et al 2005a(Machwe et al , 2005b include a component-based representation, the inclusion of both rule-based and user-based aesthetic criteria, the associated inclusion of 'hard' criteria regarding stability and materials usage, and agent-based assembly of the initial population. The explicitly defined aesthetics are included through rules derived from studies on bridge design whereas subjective aesthetic evaluation is provided by the user.…”

Integrating aesthetic criteria with evolutionary processes in complex, free-form design – an initial investigation

“…A detailed discussion of factors which make such a system difficult to implement within a real world context can be found in Machwe et al [7]. Such factors have led to an approach commencing with a relatively simple system before slowly increasing the complexity of the problem.…”