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Title: Dynamical logical circuits in excitable chemical systems
Author: Zhang, Liang
ISNI:       0000 0004 2734 0187
Awarding Body: University of the West of England, Bristol
Current Institution: University of the West of England, Bristol
Date of Award: 2012
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This project aims to construct logical circuits in models of chemical media, including two cellular automata models: the 2+ -medium and the spiral rule, as well as a numerical simulation model of the light-sensitive Belousov-Zhabotinsky (BZ) medium. The 2+ -medium is a two-dimensional three-state cellular automaton model of the excitable medium. Each cell takes one of the three possible states: excited, refractory and resting. All cells update their states simultaneously in discrete time depending on the states of its eight neighbours. A resting cell becomes excited if it has exactly two excited neighbours, and the transitions from excited state to refractory state, and from refractory state to resting state are unconditional. Binary adders and multipliers are implemented in the 2+ -medium . The spiral rule is a three-state k-totalistic cellular automaton on a two-dimensional lattice with hexagonal tiling. Each cell has three possible states: 0, 1 and 2, and a 7- cell neighbourhood consisting of the cell itself as well as its six closest neighbours. The spiral rule can also be interpreted as a model of reaction-diffusion chemical system. Many structures emerge while evolving the spiral rule, including gliders, stationary eaters and glider guns. Binary counters and adders are implemented in the spiral rule. The light-sensitive ruthenium-catalysed BZ medium has a feature that its excitability can be controlled by adjusting the light intensity. While the excitability is in the sub-excitable state, wave-fragments can be initiated, providing a means to perform collision-based computing in real chemical media. In this project, a two-variable Oregonator model is used to simulate such a medium. A 1-bit half adder is implemented in the simulated medium with wave-fragments constrained by channels.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available