New Computer will Mimic Human Brain -- And I'm Kinda Scared (Patreon)

[This is a transcript with links to references.]

A lab in Australia is building a new supercomputer that will for the first time both physically resemble a human brain, and perform as many operations as possible, about 228 trillion per second.The scary bit is how few operations this are. Yes, how few. Let me explain.

The new supercomputer will be built at the at Western Sydney University. It’s part of a new paradigm called “neuromorphic” computing, that’s computers modelled after the so far best processing apparatuses that nature has given us. BRAINS.

Neuromorphic computing isn’t the same as artificial intelligence. These are two different research areas with different goals. What they have in common are neural networks.

You may know neural networks as the most important software behind artificial intelligence. But while these neural networks do in some sense resemble the neural networks in the human brain, they’re different from the real thing in one very important way. It’s that for AIs, the structure of the neural network is represented in the software, but the physical basis is still transistors lined up on microchips. In the human brain, in contrast, the network is a physical thing. It’s one with the algorithm that runs on it.

This difference is what scientists and engineers want to remove with the neuromorphic computers. These are built to resemble a human brain in terms of hardware, not just in terms of the algorithm that runs on it. This doesn’t mean that they’re built from biological tissue, it just means that the connectivity and functionality of the biological tissue is reflected in the structure of the neuromorphic processor. So the thing doesn’t actually look like a brain, it’s still a box with wires in it, but it works differently than your phone.

The term “neuromorphic” is somewhat vague and encompasses a lot of different things. In some research settings, for example, they basically throw a bunch of wires atop each other to create a network and call that neuromorphic. Some researchers have succeeded with teaching these wires to recognize hand-drawn numbers by adjusting how well the junctions conduct electricity and from there it’s just a small step until they run for president.

Somewhat more sophisticated than a handful of wires is IBM’s “TrueNorth” processor that they first put forward in 2014. It had 1 million cores, each designed to resemble the way neurons fire in the brain, and specifically designed to map the “virtual” neurons of a neural net on the physical ones. IBM has since updated and improved its neuromorphic processors, but they’re still far smaller than the human brain.

The new computer to be built in Sydney is named “DeepSouth” not just to acknowledge its location, but it’s also a nod to Google’s Deepmind and IBM’s TrueNorth. The new computer will however work completely different than either.

The researchers in Sydney want to use what’s called Field Programmable Gate Arrays, that are basically small circuits whose function, in contrast to normal microprocessors, can still be electronically changed. These programmable arrays will take on the function of neurons and simulate in particular the “spiking”, that is the rather sudden threshold at which neurons pass on information. In addition, they’ll be building in some randomness into the behaviour of these artificial neurons because that seems to be playing an important, if not well understood, role in the human brain.

The point of this research project is not to build a super powerful computer. That’d be more difficult because then you’d have to figure out how to train this neural network. For the moment, they just want to find out how the human brain manages to run on so little power. It barely needs 20 Watts to operate, whereas training the currently existing artificial intelligences consumes huge amounts of energy, and running them isn’t cheap either. Sooner or later, this is about to become a problem. Mapping the neural networks from the software to the hardware could dramatically decrease the energy requirement.  

Another reason that they use these FPGAs is that they are slow. You see, neurons in the human brain need a few milliseconds or so to update their state because it’s all chemical reactions. You might find that fast, but remember that modern computer processors update billions of times a second. So they’re easily a million times faster than the neurons in our brains. If you want to build something that physically resembles a human brain, therefore, you need slow electronics, so this is what they’ll be doing. The researchers plan to complete the Deep South computer by April this year. It will be remotely accessible for research purposes though I suppose the waiting list will be quite long.

Of course this opens the possibility that once they’ve managed to get this done, they might be able to build a device that works like a human brain but a million times faster which, erm, isn’t scary at all.