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Memristor Breakthrough: First Single Device To Act Like a Neuron

2020-09-01 Samuel K. Moore

It combines resistance, capacitance, and what’s called a Mott memristor all in the same device. Memristors are devices that hold a memory, in the form of resistance, of the current that has flowed through them. Mott memristors have an added ability in that they can also reflect a temperature-driven change in resistance. Materials in a Mott transition go between insulating and conducting according to their temperature. It’s a property seen since the 1960s, but only recently explored in nanoscale devices.

The transition happens in a nanoscale sliver of niobium oxide in the memristor. Here when a DC voltage is applied, the NbO2 heats up slightly, causing it to transition from insulating to conducting. Once that switch happens, the charge built up in the capacitance pours through. Then the device cools just enough to trigger the transition back to insulating. The result is a spike of current that resembles a neuron’s action potential.

https://spectrum.ieee.org/nanoclast/semiconductors/devices/memristor-first-single-device-to-act-like-a-neuron

Also: https://www.nature.com/articles/s41586-020-2735-5.epdf?sharing_token=B11PDbIH67ccrQscLpqM19RgN0jAjWel9jnR3ZoTv0OdeNphDinnZf2DfBr6sMtOQnlA9ClIX5PlqiQovl5PS67A1_SeUDz_GOTcpm9U8FJOwFmzPM8n_1wR_XcVzo9nasoynqgc04XmOkuXv1UxU95v5wjS-eNBbDS0aEI6zvz9aX0jlTRX9soTeiiWwoHX-JFpZUeYiamNdcA3x8Vr8eOQFWRjS7vQ0Ji-WYiQAvIhdiylBLMCTx5sY6HEBVNO2EAlUzWxg8JW4JFhkFf9Fd_P8V18BwKJ_k_eJ2TofXNsyjmPTa-r98OT104dU21Eev4zf-LFX6_7z34scRoUTA%3D%3D&tracking_referrer=spectrum.ieee.org

Artificial brains may need sleep too

2020-06-08 James Riordon

States that resemble sleep-like cycles in simulated neural networks quell the instability that comes with uninterrupted self-learning in artificial analogs of brains

Watkins and her research team found that the network simulations became unstable after continuous periods of unsupervised learning. When they exposed the networks to states that are analogous to the waves that living brains experience during sleep, stability was restored. “It was as though we were giving the neural networks the equivalent of a good night’s rest,” said Watkins.

https://www.lanl.gov/discover/news-release-archive/2020/June/0608-artificial-brains.php

Spiking Neural Networks

2020-02-17 Martijn van Wezel

The SNNs bio-inspired neural networks are different from conventional neural networks due that the conventional neural networks communicate with numbers. Instead, SNNs communicate through spikes. … Having multiple spikes in a short period can stimulate the neuron to fire. However, if the time periods are to big between spikes, the neuron lose interest, and goes to sleep again.

… one major benefit of a Spiking Neural Networks is the power consumption. A ‘normal’ neural network uses big GPUs or CPUs that draw hundreds of Watts of power. SNN only uses for the same network size just a few nano Watts.

https://martijnvwezel.com/blogs/spiking_neural_networks/

Machine Learning Takes On Antibiotic Resistance

2020-03-09 Katherine Harmon Courage

In the February 20 issue of Cell, one team of scientists announced that they — and a powerful deep learning algorithm — had found a totally new antibiotic, one with an unconventional mechanism of action that allows it to fight infections that are resistant to multiple drugs. The compound was hiding in plain sight (as a possible diabetes treatment) because humans didn’t know what to look for. …

Collins, Barzilay and their team trained their network to look for any compound that would inhibit the growth of the bacterium Escherichia coli. They did so by presenting the system with a database of more than 2,300 chemical compounds that had known molecular structures and were classified as “hits” or “non-hits” on tests of their ability to inhibit the growth of E. coli. From that data, the neural net learned what atom arrangements and bond structures were common to the molecules that counted as hits. …

The researchers … also trained the algorithm to predict the toxicity of compounds and to weed out candidate molecules on that basis. …

They then turned the trained network loose on the Drug Repurposing Hub, a library of more than 6,000 compounds that are already being vetted for use in humans for a wide variety of conditions.

https://www.quantamagazine.org/machine-learning-takes-on-antibiotic-resistance-20200309/

Sonic’s very fast redesign

When the redesign [of the Sonic the Hedgehog movie] was commissioned, Artist Tyson Hesse, who had worked on previous Sonic the Hedgehog media, was brought on to lead the redesign. “But a lot of the work that the team had already done as far as the look of Sonic’s fur, should he have eyelashes and what they look like…how we should handle the eyes…all that kind of stuff was actually directly translatable over to the new design,” comments Wright. “I think the redesign took only seven or eight weeks, which is a record at MPC for the design of a 3D character.”

The process was helped by Hesse having a strong relationship with Sega previously. The team flew to London, “where we all sat with the guy that was concept sculpting and literally just did it in real-time.” Wright felt that because there was a clear remit for Hesse to take the redesign lead, it allowed everything to fall into place very simply. “Actually, funnily enough, the redesign was pretty painless. In some respects, a more exaggerated character is a simpler thing for the team to execute,” he comments.

https://www.fxguide.com/fxfeatured/sonics-very-fast-redesign/