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Posted: Feb 10, 2014
Brain jelly - design and construction of an organic, brain-like computer
(Nanowerk Spotlight) In a previous Nanowerk Spotlight we reported on the concept of a full-fledged massively parallel organic computer at the nanoscale that uses extremely low power ("Will brain-like evolutionary circuit lead to intelligent computers?"). In this work, the researchers created a process of circuit evolution similar to the human brain in an organic molecular layer. This was the first time that such a brain-like 'evolutionary' circuit had been realized.
The research team, led by Dr. Anirban Bandyopadhyay, a senior researcher at the Advanced Nano Characterization Center at the National Institute of Materials Science (NIMS) in Tsukuba, Japan, has now finalized their human brain model and introduced the concept of a new class of computer which does not use any circuit or logic gate.
Over the past decades, digital computers have consistently increased in speed and complexity – China's Tianhe-2, currently the fastest supercomputer in the world, can execute a blistering 33.86 petaFLOPS, or 33.86 quadrillion floating point operations per second. Nevertheless, these machines are limited by their reliance on sequential processing of instructions; i.e. no matter how fast they are, they still process only one bit at a time.
By contrast, individual neurons in our brain are very slow: they fire at only about 1000 times per second; however, since they are operating in a massively parallel way, with millions of neurons working collectively, they are able to complete certain tasks more efficiently than even the fastest supercomputer. Another important distinction of our brain is that, during computing, information processing circuits evolve continuously to solve complex problems.
"Our artificial brain-building project differs from all others in the world for several reasons," Bandyopadhyay explains to Nanowerk. He lists the four major distinctions:
1) We do not use logic gate based computing within the framework of Turing, our decision-making protocol is not a logical reduction of decision rather projection of frequency fractal operations in a real space, it is an engineering perspective of Gödel’s incompleteness theorem.
2) We do not need to write any software, the argument and basic phase transition for decision-making, 'if-then' arguments and the transformation of one set of arguments into another self-assemble and expand spontaneously, the system holds an astronomically large number of 'if' arguments and its associative 'then' situations.
3) We use 'spontaneous reply back', via wireless communication using a unique resonance band coupling mode, not conventional antenna-receiver model, since fractal based non-radiative power management is used, the power expense is negligible.
4) We have carried out our own single DNA, single protein molecule and single brain microtubule neurophysiological study to develop our own Human brain model.
The kind of CMOS based integrated chip that forms the core of existing supercomputers will not be used in this kind of computer. Bandyopadhyay uses the term brain jelly to describe the purely organic computing architecture.
The first step of constructing the brain jelly is to construct a protein-like molecule which – if triggered by an electromagnetic signal – starts self-assembly.
(a) Every single seed of the brain architecture has a helical symmetry just like the human brain; (b) The complete design of the organic supramolecular architecture based human brain. The egg-shaped complete brain has two parts (left), the upper part holds 'brain jelly', the spinal cord and the mid brain is inside this egg, shown separately in the right. (c) The experimental set up where the researchers study the circuit evolution of a brain jelly; (d) The microscope image capture of a video when 7nm seed creates visible brain circuits. (click image to enlarge)
"Recently, we have succeeded in self-assembling such an architecture, where a 7 nm organic molecular seed expands to another seed of 20 nm, which then is automatically coupled with several others to trigger another self-assembly of helical nanowire," says Bandyopadhyay. –In this way, the self-assembly continues, this is one of the finest examples of multilayered hierarchical self-assembly."
Once the basic neuron structure is synthesized, different versions of synthetic neurons are also created. Modified versions of neurons are used only for self-assembling them in the form of a wire, spiral, glia like spherical, or semicircular assemblies.
The sensors for the artificial brain are also different from the existing world of sensors.
"We use a new kind of wireless sensor technology," notes Bandyopadhyay. "In this technique, we use resonant oscillations of the sensing molecules following mechanical, chemical or electromagnetic energy in creating pulses of different kinds and then convert all complex-shaped pulses in to a wave train of rectangular pulses but with different time gaps. Thus, all kinds of sensory data are converted in terms of one and only one parameter that is frequency. There exists a universal coding protocol for all sensors as far as the global time gaps are concerned, which isolates multiple distinct frequency signals."
Power supply for this brain-like computer comes from a chemical nano-battery.
The researchers emphasize that their organic molecular systems are not alive. For computation, they do not even require to switch on and off the conducting states just like conventional computer; they simply need power to maintain a potential difference between the protein molecule and every single oscillator.
"This is a simple condition, however, it is a critical challenge," says Bandyopadhyay. "In the biological brain, we have neurons firing and the membrane potential helps all oscillators in the layers below and above the neuron scale, at every layer. Attaching a small battery to individual oscillators is an impossible task. Instead, we follow the same trick developed by nature for our artificial brain, too. Inside the spherical cavity of the neuroglia and in the neuron we implant the nano-batteries, alternately, ionic conduction protocols could also be implemented just like the real biological brain."
The brain jelly architecture has negligible power consumption. While existing supercomputers have enormous power requirements, a brain jelly computer works on a few watts only. The reason for the extremely low power consumption is the use of resonant coupling and decoupling of electrical pulses as the basic event of computation. There is no electrical wiring, no logic operation, hence no power loss.
There is no need to write any software.
This is very much like our human brain. In a normal computer a software engineer types instructions, and the computer follows these instructions. The hardware has no intelligence to cook logic and combine multiple different logic to generate something new, that never existed before.
"In our system, the sensors capture the 'if-then' arguments and self-assemble the arguments," Bandyopadhyay explains. "This is new – 'self-assembly' replaces software engineers. Thus, for every new input, the computer itself creates unforeseen sets of arguments and projects the solution considering every single parameter."
A beyond Turing path of computation.
"The problem with the Turing tape based computing is that all possible arguments should be known beforehand and the entire processing scheme should be defined strictly, as an output of step-by-step logical reduction process," says Bandyopadhyay. "But all traditional computers work within the domain of Turing."
"However, in our case this is an adventure to the higher order logic that could not be converted in terms of set theory," he continues. "We find our computer a perfect example of Russel's paradox, which proved that higher order logic could reach a situation when set theory would collapse."
"Note that existing world of technologies follow only first-order logic, which follows only sets of 'if-then' statements. Therefore we do not have a truth table like a conventional computer, rather a infinitely tall columns of arguments connected by their properties."
Spontaneous reply-back – performing a search without searching.
The biggest problem of the existing world is the data deluge, when we do not have time and the computing power to analyze a large amount of data due to quantity and complexity of the situation. To address this issue, the research team introduced the concept of spontaneous reply-back which supersedes even the exponential speedup promised by a quantum computer.
"This is like the 'needle in a hay-stack' problem" says Bandyopadhyay. "If you search, you'll never find it. But if you take a strong enough magnet, then the needle will come out of the haystack. In a way, the needle spontaneously replies back to the magnet. In a huge data situation, where searching becomes impossible, then, if we could use this technique – spontaneous reply back – then we can solve the problem."
"In our case, we are making a pattern-based computer, which means all kinds of information are stored in the computer like a complex 3D pattern (the 'hay')," he elaborates. "Now, every problem is just like a small 3D pattern (the 'needle') and we need to find a match for it in the large pattern."
The team's brain jelly – which basically is an organic jelly of oscillators – stores 3D patterns by learning. Now, when you 'ask' these oscillators a question – by sending another small 3D pattern – only those oscillators which are holding the same or a similar pattern respond.
Though the researchers are using an organic supramolecular system for brain-like computing, their brain-building task has been largely simplified because they are not using chemicals. The brain jelly does not require the massive complexity of hormones, enzymes, and vital tasks that the human brain employs to safeguard the living body.
"Our exploration would deliver a human-like brain for robots or sophisticated industrial machines," concludes Bandyopadhyay. "At the same time, it would open up a new physical world of biology squarely parallel to the chemical-only genetic and molecular biology that exists today."