Generative representations for evolutionary design automation.

摘要

In this thesis the class of generative representations is defined and it is shown that this class of representations improves the scalability of evolutionary design systems by automatically learning inductive bias of the design problem thereby capturing design dependencies and better enabling search of large design spaces. First, properties of representations are identified are classified as non-generative, or generative. Whereas non-generative representations use elements of encoded artifacts at most once in translation from encoding to actual artifact; generative representations have the ability to reuse parts of the data structure for encoding artifacts Unlike non-generative representations, which do not scale with design complexity because they cannot capture design dependencies in their structure, it is argued that evolution with generative representations can better scale with design complexity because of their ability to hierarchically create assemblies of modules for reuse, thereby enabling better search of large design spaces. Second, GENRE, an evolutionary design system using a generative representation, is described. Using this system, a non-generative and a generative representation are compared on four classes of designs: three-dimensional static structures constructed from voxels; neural networks; actuated robots controlled by oscillator networks; and neural network controlled robots. Results from evolving designs in these substrates show that the evolutionary design system is capable of finding solutions of higher fitness with the generative representation than with the non-generative representation. This improved performance is shown to be a result of the generative representation's ability to capture intrinsic properties of the search space and its ability to reuse parts of the encoding in constructing designs. By capturing design dependencies in its structure, variation operators are more likely to be successful with a generative representation than with a non-generative representation. Second, reuse of data elements in encoded designs improves the ability of an evolutionary algorithm to search large design spaces.*; *This dissertation is a multimedia document (contains text and other applications not available in printed format). The CD requires the following system requirements: Adobe Acrobat.