Nothing computes more efficiently than a brain, which is why scientists are working hard to create artificial neural networks that mimic the organ as closely as possible. Conventional approaches use artificial neurons that work together to learn different tasks and analyze data; however, these artificial neurons do not have the ability to actually “fire” like real neurons, releasing bursts of electricity that connect them to other neurons in the network. The third generation of this computing tech aims to capture this real-life process more accurately – but achieving such a feat is hard to do efficiently.

In a study published 30 April in IEEE Transactions on Electron Devices, a group of researchers in India propose a novel approach that allows these artificial neurons to fire in a much more efficient manner, allowing more “neurons” to be packed onto a computer chip. The advancement takes us one step closer to achieving more practical spiking neural networks (SNNs). This type of network could help us better understand the very organ that it’s inspired by, and thus better understand human disease, thought processes, and other mysteries of the brain.

Neurons in the brain “communicate” with each other by transmitting electrical spikes between one another. Networks of artificial spiking neurons can imitate this phenomenon by using leaky capacitors. Once a capacitor reaches a given threshold of electric charge, the voltage or current shoots out and affects the neighboring capacitor (analogous to another neuron).

A group of researchers at the Indian Institute of Technology Bombay designed the new SNN hardware. The design includes silicon-based electrical switches, called Metal-Oxide Semiconductor Field-Effect Transistors (MOSFETs), which are built on an insulating substrate.

To help the “neuron” fire and activate the other capacitors, the team added positively charged holes to the MOSFETs. Based on the nature of the MOSFETs, these holes allow for the quantum mechanical tunneling of electrons out of the capacitor. “The use of quantum mechanical tunneling provides incredible control, which is a huge advantage,” says Tanmay Chavan, a member of the research team that developed the SNN.

What’s more, this design can work in an off-current mode, which allows the capacitors to be 10,000 times smaller than if they required the current to be on. “In fact, the body capacitance is used to integrate the current within the transistor, leading us to utilize such tiny currents accurately without external loss,” explains Udayan Ganguly, another researcher at IIT Bombay involved in the study. “This… leads to extreme energy efficiency that we refer to as ‘computing at the current floor.’ Thus, fantastic energy and density is achieved.”

The researchers are interested in commercializing this design and are currently looking into forming new partnerships. “Given the fantastic performance at a unit neuron level, we plan to demonstrate networks of such neurons to understand how models of networks of neurons behave on silicon. This will enable us to understand the robustness and systems-level efficiency of the technology,” Chavan says.

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The Spectacular Collapse of CryptoKitties, the First Big Blockchain Game

A cautionary tale of NFTs, Ethereum, and cryptocurrency security

8 min read
Mountains and cresting waves made of cartoon cats and large green coins.
Frank Stockton

On 4 September 2018, someone known only as Rabono bought an angry cartoon cat named Dragon for 600 ether—an amount of Ethereum cryptocurrency worth about US $170,000 at the time, or $745,000 at the cryptocurrency’s value in July 2022.

It was by far the highest transaction yet for a nonfungible token (NFT), the then-new concept of a unique digital asset. And it was a headline-grabbing opportunity for CryptoKitties, the world’s first blockchain gaming hit. But the sky-high transaction obscured a more difficult truth: CryptoKitties was dying, and it had been for some time.

The launch of CryptoKitties drove up the value of Ether and the number of transactions on its blockchain. Even as the game's transaction volume plummeted, the number of Ethereum transactions continued to rise, possibly because of the arrival of multiple copycat NFT games.

That perhaps unrealistic wish becomes impossible once the downward spiral begins. Players, feeling no other attachment to the game than growing an investment, quickly flee and don’t return.

Whereas some blockchain games have seemingly ignored the perils of CryptoKitties’ quick growth and long decline, others have learned from the strain it placed on the Ethereum network. Most blockchain games now use a sidechain, a blockchain that exists independently but connects to another, more prominent “parent” blockchain. The chains are connected by a bridge that facilitates the transfer of tokens between each chain. This prevents a rise in fees on the primary blockchain, as all game activity occurs on the sidechain.

Yet even this new strategy comes with problems, because sidechains are proving to be less secure than the parent blockchain. An attack on Ronin, the sidechain used by Axie Infinity, let the hackers get away with the equivalent of $600 million. Polygon, another sidechain often used by blockchain games, had to patch an exploit that put $850 million at risk and pay a bug bounty of $2 million to the hacker who spotted the issue. Players who own NFTs on a sidechain are now warily eyeing its security.

Remember Dragon

The cryptocurrency wallet that owns the near million dollar kitten Dragon now holds barely 30 dollars’ worth of ether and hasn’t traded in NFTs for years. Wallets are anonymous, so it’s possible the person behind the wallet moved on to another. Still, it’s hard not to see the wallet’s inactivity as a sign that, for Rabono, the fun didn’t last.

Whether blockchain games and NFTs shoot to the moon or fall to zero, Bladon remains proud of what CryptoKitties accomplished and hopeful it nudged the blockchain industry in a more approachable direction.

“Before CryptoKitties, if you were to say ‘blockchain,’ everyone would have assumed you’re talking about cryptocurrency,” says Bladon. “What I’m proudest of is that it was something genuinely novel. There was real technical innovation, and seemingly, a real culture impact.”

This article was corrected on 11 August 2022 to give the correct date of Bryce Bladon's departure from Dapper Labs.

This article appears in the September 2022 print issue as “The Spectacular Collapse of CryptoKitties.”

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