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## How Vesicles Compute With Chemical Cocktails

If small pouches of chemical cocktails are allowed to interact, they can also compute

One of the more exciting developments in computer science is the increased focus on exotic forms of computing. On this blog we’ve looked at some of them including hot ice computers, slime mould computers, reversible computing, morphological computation and quantum computing, to name just a few.

One of the leaders in this field is Andrew Adamatzky at the University of the West of England in Bristol, who has fingers in a number of the aforementioned pies.

Today, he adds another to his formidable arsenal: vesicle computing.

The vision goes like this. Imagine a honeycomb of cells, each containing a chemical cocktail capable of supporting various reactions, such as the ability to form precipitates. Imagine also that these cells are permeable so that the state of one cell can ‘leak’ into its neighbours where it can trigger other reactions.

Its probably no surprise that such a system can support a rich and complex set of behaviours as the different chemical states sweep across the honeycomb in waves. These waves can even carry out certain types of computation, such as solving mazes.

The problem is that in real life, regular honeycombs are rather hard to come by. Instead, the chemical pouches or vesicles that hold interesting chemical cocktails tend to occur in all kinds of shapes and sizes and form hugely irregular patterns.

Today Adamatzky and a few buddies raise an interesting question. “What kind of computation can be done on an irregular arrangement of non-uniform vesicles?” they ask.

They tackle this question by creating a model of this kind of system using Voronoi diagrams, a way of dividing up a flat space into an irregular pattern with a well defined rule.

They go on to think of the resulting pattern as a cellular automaton and show that this ‘Voronoi automaton’ can solve certain problems of computational geometry, such as making skeleton patterns of arbitrary shapes.

That’s potentially useful because it removes a significant constraint on the manufacture of these kinds of computer. Instead of requiring highly regular cells of chemicals, as might be expected of a computing machine, vesicle computers ought to work just as well if they are thrown together, like ingredients in a cake.

Of course, it’s a big step from this theoretical work to actually baking a cake that computes. But thre are groups out there trying.

The dream is make vesicle computers that act like microfactories, where the results of their computations are chemicals that form into useful objects, a bit like 3D printers but more living cells and the molecular machines they contain that make the building blocks of life.

We know these machines compute–they work like tiny Turing machines. The possibility that vesicle computing raises is that computing may also be occurring on an entirely different level.

Ambitious stuff.

Ref: arxiv.org/abs/1104.1707: Vesicle Computers: Approximating Voronoi Diagram On Voronoi Automata

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