Toward turing’s A-type unorganised machines in an unconventional substrate: A dynamic representation in compartmentalised excitable chemical media (2013)
Book Chapter
Bull, L., Holley, J., De Lacy Costello, B., & Adamatzky, A. (2013). Toward turing’s A-type unorganised machines in an unconventional substrate: A dynamic representation in compartmentalised excitable chemical media. . Springer. https://doi.org/10.1007/978-3-642-37225-4_11

© Springer-Verlag Berlin Heidelberg 2013. Turing presented a general representation scheme by which to achieve artificial intelligence – unorganised machines. Significantly, these were a form of discrete dynamical system and yet such representations... Read More about Toward turing’s A-type unorganised machines in an unconventional substrate: A dynamic representation in compartmentalised excitable chemical media.

Evolution of plastic learning in spiking networks via memristive connections (2012)
Journal Article
Howard, G., Howard, D., Gale, E., Bull, L., De Lacy Costello, B., & Adamatzky, A. (2012). Evolution of plastic learning in spiking networks via memristive connections. IEEE Transactions on Evolutionary Computation, 16(5), 711-729. https://doi.org/10.1109/TEVC.2011.2170199

This paper presents a spiking neuroevolutionary system which implements memristors as plastic connections, i.e., whose weights can vary during a trial. The evolutionary design process exploits parameter self-adaptation and variable topologies, allowi... Read More about Evolution of plastic learning in spiking networks via memristive connections.

Creating unorganised machines from memristors (2012)
Presentation / Conference
Howard, G. D., Bull, L., Costello, B. D. L., & Adamatzky, A. (2012, September). Creating unorganised machines from memristors. Paper presented at ICNAAM 2012: International Conference of Numerical Analysis and Applied Mathematics, Kos, Greece

On architectures of circuits implemented in simulated Belousov-Zhabotinsky droplets (2012)
Journal Article
Adamatzky, A., Holley, J., Dittrich, P., Gorecki, J., De Lacy Costello, B., Zauner, K. P., & Bull, L. (2012). On architectures of circuits implemented in simulated Belousov-Zhabotinsky droplets. BioSystems, 109(1), 72-77. https://doi.org/10.1016/j.biosystems.2011.12.007

When lipid vesicles filled with Belousov-Zhabotinsky (BZ) excitable chemical medium are packed in tight assembles, waves of excitation may travel between the vesicles. When several waves meet in a vesicle some fragments may deflect, others can annihi... Read More about On architectures of circuits implemented in simulated Belousov-Zhabotinsky droplets.

Logical and arithmetic circuits in Belousov-Zhabotinsky encapsulated disks (2011)
Journal Article
Holley, J., Jahan, I., De Lacy Costello, B., Bull, L., & Adamatzky, A. (2011). Logical and arithmetic circuits in Belousov-Zhabotinsky encapsulated disks. Physical Review E, 84(5), 056110. https://doi.org/10.1103/PhysRevE.84.056110

Excitation waves on a subexcitable Belousov-Zhabotinsky (BZ) substrate can be manipulated by chemical variations in the substrate and by interactions with other waves. Symbolic assignment and interpretation of wave dynamics can be used to perform log... Read More about Logical and arithmetic circuits in Belousov-Zhabotinsky encapsulated disks.

On computing in fine-grained compartmentalised Belousov-Zhabotinsky medium (2011)
Journal Article
Adamatzky, A., Holley, J., Bull, L., & De Lacy Costello, B. (2011). On computing in fine-grained compartmentalised Belousov-Zhabotinsky medium. Chaos, Solitons and Fractals, 44(10), 779-790. https://doi.org/10.1016/j.chaos.2011.03.010

We introduce results of computer experiments on information processing in a hexagonal array of vesicles filled with Belousov-Zhabotinsky (BZ) solution in a sub-excitable mode. We represent values of Boolean variables by excitation wave-fragments and... Read More about On computing in fine-grained compartmentalised Belousov-Zhabotinsky medium.

Vesicle computers: Approximating a Voronoi diagram using Voronoi automata (2011)
Journal Article
Adamatzky, A., De Lacy Costello, B., Holley, J., Gorecki, J., & Bull, L. (2011). Vesicle computers: Approximating a Voronoi diagram using Voronoi automata. Chaos, Solitons and Fractals, 44(7), 480-489. https://doi.org/10.1016/j.chaos.2011.01.016

Irregular arrangements of vesicles filled with excitable and precipitating chemical systems are imitated by Voronoi automata - finite-state machines defined on a planar Voronoi diagram. Every Voronoi cell takes four states: resting, excited, refracto... Read More about Vesicle computers: Approximating a Voronoi diagram using Voronoi automata.

Evolving spiking networks with variable memristors (2011)
Presentation / Conference
Howard, G. D., Gale, E., Bull, L., de Lacy Costello, B., & Adamatzky, A. (2011, June). Evolving spiking networks with variable memristors. Paper presented at 13th annual conference on Genetic and evolutionary computation

Towards evolving spiking networks with memristive synapses (2011)
Presentation / Conference
Howard, G. D., Gale, E., Bull, L., de Lacy Costello, B., & Adamatzky, A. (2011, April). Towards evolving spiking networks with memristive synapses. Paper presented at IEEE Symposium on Artificial Life (ALIFE), 2011, Paris, France

This paper presents a spiking neuro-evolutionary system which implements memristors as neuromodulatory connections, ie whose weights can vary during a trial. The evolutionary design process exploits parameter self-adaptation and a constructionist app... Read More about Towards evolving spiking networks with memristive synapses.

Computational modalities of Belousov-Zhabotinsky encapsulated vesicles (2011)
Journal Article
Holley, J., Adamatzky, A., Bull, L., De Lacy Costello, B., & Jahan, I. (2011). Computational modalities of Belousov-Zhabotinsky encapsulated vesicles. Nano Communication Networks, 2(1), 50-61. https://doi.org/10.1016/j.nancom.2011.02.002

We present both simulated and partial empirical evidences for the computational utility of many connected vesicle analogues of an encapsulated nonlinear chemical processing medium. By connecting small vesicles containing a solution of sub-excitable B... Read More about Computational modalities of Belousov-Zhabotinsky encapsulated vesicles.

On polymorphic logical gates in subexcitable chemical medium (2011)
Journal Article
Adamatzky, A., De Lacy Costello, B., & Bull, L. (2011). On polymorphic logical gates in subexcitable chemical medium. International Journal of Bifurcation and Chaos, 21(07), 1977-1986. https://doi.org/10.1142/S0218127411029574

In a subexcitable light-sensitive Belousov-Zhabotinsky (BZ) chemical medium an asymmetric disturbance causes the formation of localized traveling wave-fragments. Under the right conditions these wave-fragments can conserve their shape and velocity ve... Read More about On polymorphic logical gates in subexcitable chemical medium.

Towards arithmetic circuits in sub-excitable chemical media (2011)
Journal Article
Adamatzky, A., De Lacy Costello, B., Bull, L., & Holley, J. (2011). Towards arithmetic circuits in sub-excitable chemical media. Israel Journal of Chemistry, 51(1), 56-66. https://doi.org/10.1002/ijch.201000046

A sub-excitable Belousov-Zhabotinsky medium exhibits localized travelling excitations (in contrast to an excitable medium exhibiting target or spiral waves). Initially assymetric perturbations give birth to excitation wave-fragments. The shape and ve... Read More about Towards arithmetic circuits in sub-excitable chemical media.

Experimental validation of binary collisions between wave fragments in the photosensitive Belousov-Zhabotinsky reaction (2009)
Journal Article
Toth, R., Stone, C., Adamatzky, A., de Lacy Costello, B., & Bull, L. (2009). Experimental validation of binary collisions between wave fragments in the photosensitive Belousov-Zhabotinsky reaction. Chaos, Solitons and Fractals, 41(4), 1605-1615. https://doi.org/10.1016/j.chaos.2008.07.001

We present experimental verification of wave fragment collisions in the sub-excitable Belousov-Zhabotinsky medium observed previously in simulation [Adamatzky A, De Lacy Costello B. Binary collisions between wave fragments in a sub-excitable Belousov... Read More about Experimental validation of binary collisions between wave fragments in the photosensitive Belousov-Zhabotinsky reaction.

Experimental validation of binary collisions between wave fragments in the photosensitive Belousov–Zhabotinsky reaction (2009)
Journal Article
Toth, R., Stone, C., Adamatzky, A., de Lacy Costello, B., & Bull, L. (2009). Experimental validation of binary collisions between wave fragments in the photosensitive Belousov–Zhabotinsky reaction. Chaos, Solitons and Fractals, 41(4), 1605-1615. https://doi.org/10.1016/j.chaos.2008.07.001

Using the examples of an excitable chemical system (the Belousov–Zhabotinsky medium) and plasmodium of Physarum polycephalum we show that universal computation in a geometrically unconstrained medium is only possible when resources (excitability or c... Read More about Experimental validation of binary collisions between wave fragments in the photosensitive Belousov–Zhabotinsky reaction.

Spiral formation and degeneration in heterogeneous excitable media (2009)
Journal Article
Toth, R., De Lacy Costello, B., Stone, C., Masere, J., Adamatzky, A., & Bull, L. (2009). Spiral formation and degeneration in heterogeneous excitable media. Physical Review E, 79(3), 035101(R) (4 pages). https://doi.org/10.1103/PhysRevE.79.035101

Spontaneous spiral formation occurs when an excitation wave is input to a heterogeneous network of low- and high-light-intensity cells projected onto a light-sensitive Belousov-Zhabotinsky reaction. The range of network conditions where spirals form... Read More about Spiral formation and degeneration in heterogeneous excitable media.

Implementation of glider guns in the light-sensitive Belousov-Zhabotinsky medium (2009)
Journal Article
De Lacy Costello, B., Toth, R., Stone, C., Adamatzky, A., & Bull, L. (2009). Implementation of glider guns in the light-sensitive Belousov-Zhabotinsky medium. Physical Review E, 79(2), 026114. https://doi.org/10.1103/PhysRevE.79.026114

In cellular automata models a glider gun is an oscillating pattern of nonquiescent states that periodically emits traveling localizations (gliders). The glider streams can be combined to construct functionally complete systems of logical gates and th... Read More about Implementation of glider guns in the light-sensitive Belousov-Zhabotinsky medium.

Simple collision-based chemical logic gates with adaptive computing (2009)
Journal Article
Toth, R., Stone, C., de Lacy Costello, B., Adamatzky, A., & Bull, L. (2009). Simple collision-based chemical logic gates with adaptive computing. International Journal of Nanotechnology and Molecular Computation, 1(3), 1-16. https://doi.org/10.4018/jnmc.2009070101

Dynamic control and information processing in the Belousov-Zhabotinsky reaction using a coevolutionary algorithm (2008)
Journal Article
Toth, R., Stone, C., Adamatzky, A., De Lacy Costello, B., & Bull, L. (2008). Dynamic control and information processing in the Belousov-Zhabotinsky reaction using a coevolutionary algorithm. Journal of Chemical Physics, 129(18), 184708. https://doi.org/10.1063/1.2932252

We propose that the behavior of nonlinear media can be controlled dynamically through coevolutionary systems. In this study, a light-sensitive subexcitable Belousov-Zhabotinsky reaction is controlled using a heterogeneous cellular automaton. A checke... Read More about Dynamic control and information processing in the Belousov-Zhabotinsky reaction using a coevolutionary algorithm.

Co-evolving cellular automatat with memory for chemical computing: Boolean logic gates in the BZ reaction (2008)
Presentation / Conference
Stone, C., Toth, R., de Lacy Costello, B., Adamatzky, A., & Bull, L. (2008, September). Co-evolving cellular automatat with memory for chemical computing: Boolean logic gates in the BZ reaction. Paper presented at 10th International Conference Parallel problem solving from Nature- PPSN X, Dortmund, Germany

Coevolving cellular automata with memory for chemical computing: Boolean logic gates in the BZ reaction (2008)
Book Chapter
Stone, C., Toth, R., de Lacy Costello, B., Bull, L., & Adamatzky, A. (2008). Coevolving cellular automata with memory for chemical computing: Boolean logic gates in the BZ reaction. In G. Rudolph, T. Jansen, S. M. Lucas, C. Poloni, & N. Beume (Eds.), Parallel Problem Solving from Nature - PPSN X: 10th International Conference Dortmund, Germany, September 13-17, 2008 (579-588). Berlin/Heidelberg: Springer