- Title
- Hardware evolution of a digital circuit using a custom VLSI architecture
- Creator
- Van den Berg, Allan Edward
- Subject
- Digital electronics
- Subject
- Field programmable gate arrays
- Subject
- Sequential machine theory
- Date Issued
- 2013
- Date
- 2013
- Type
- Thesis
- Type
- Masters
- Type
- MEngineering (Mechatronics)
- Identifier
- vital:9661
- Identifier
- http://hdl.handle.net/10948/d1020984
- Description
- This research investigates three solutions to overcoming portability and scalability concerns in the Evolutionary Hardware (EHW) field. Firstly, the study explores if the V-FPGA—a new, portable Virtual-Reconfigurable-Circuit architecture—is a practical and viable evolution platform. Secondly, the research looks into two possible ways of making EHW systems more scalable: by optimising the system’s genetic algorithm; and by decomposing the solution circuit into smaller, evolvable sub-circuits or modules. GA optimisation is done is by: omitting a canonical GA’s crossover operator (i.e. by using an algorithm); applying evolution constraints; and optimising the fitness function. The circuit decomposition is done in order to demonstrate modular evolution. Three two-bit multiplier circuits and two sub-circuits of a simple, but real-world control circuit are evolved. The results show that the evolved multiplier circuits, when compared to a conventional multiplier, are either equal or more efficient. All the evolved circuits improve two of the four critical paths, and all are unique. Thus, it is experimentally shown that the V-FPGA is a viable hardware-platform on which hardware evolution can be implemented; and how hardware evolution is able to synthesise novel, optimised versions of conventional circuits. By comparing the and canonical GAs, the results verify that optimised GAs can find solutions quicker, and with fewer attempts. Part of the optimisation also includes a comprehensive critical-path analysis, where the findings show that the identification of dependent critical paths is vital in enhancing a GA’s efficiency. Finally, by demonstrating the modular evolution of a finite-state machine’s control circuit, it is found that although the control circuit as a whole makes use of more than double the available hardware resources on the V-FPGA and is therefore not evolvable, the evolution of each state’s sub-circuit is possible. Thus, modular evolution is shown to be a successful tool when dealing with scalability.
- Format
- 142 pages
- Format
- Publisher
- Nelson Mandela Metropolitan University
- Publisher
- Faculty of Engineering, the Built Environment and Information Technology
- Language
- English
- Rights
- Nelson Mandela Metropolitan University
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