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PDF 1.78 MB
DOI: http://dx.doi.org/10.7551/978-0-262-33027-5-ch088
Pages 503–510
First published 20 July 2015

An Investigation of Square Waves for Evolution in Carbon Nanotubes Material

Odd Rune Lykkebø, Stefano Nichele, and Gunnar Tufte

Abstract

Materials suitable to perform computation make use of evolved configuration signals which specify how the mate-rial samples are to operate. The choice of which input and configuration parameters to manipulate obviously impacts the potential of the computational device that emerges. As such, a key challenge is to understand which parameters are better suited to exploit the underlying physical properties of the chosen material. In this paper we focus on the usage of square voltage waves as such manipulation parameters for carbon nanotubes/polymer nanocomposites. The choice of input parameters influence the reachable search space, which may be critical for any kind of evolved computational task. We provide common measurements such as power spectrum and phase plots, taken with the the Mecobo platform, a custom-built board for evolution-in-materio. In addition, an initial investigation is carried out, which links the frequency of square waves to comparability of the output from the material, while also showing differences in the material’s physical parameters. Observing the behaviour of materials under varying in-puts allows macroscopic modelling of pin-to-pin characteristics with simple RC circuits. Finally, SPICE is used to provide a rudamentary simulation of the observed properties of the material. This simulation models the per-pin behaviours, and also shows that an instance of the traveling-salesman problem can be solved with a simple randomly generated cloud of resistors.