System Bits: March 11

IoT and quantum computing; recycling EV batteries; drones over Texas.


Cryptography IC for the IoT
Massachusetts Institute of Technology researchers report their development of a cryptographic circuit that could be used to protect low-power Internet of Things devices when quantum computing takes hold.

Image Credit: MIT

The research team presented a paper at the 2019 International Solid-State Circuits Conference on how they employed a new circuit architecture and statistical optimization tricks to come up with lattice-based cryptography that could be easily integrated into IoT devices. Multiple lattice-based schemes are under study at present.

“That might be a few decades from now, but figuring out if these techniques are really secure takes a long time,” says first author Utsav Banerjee, a graduate student in electrical engineering and computer science at MIT. “It may seem early, but earlier is always better.”

Joining Banerjee on the paper are Anantha Chandrakasan, dean of MIT’s School of Engineering and the Vannevar Bush Professor of Electrical Engineering and Computer Science, and Abhishek Pathak of the Indian Institute of Technology.

The researchers say the circuit is the first of its kind to meet standards for lattice-based cryptography set by the National Institute of Standards and Technology (NIST), an agency of the U.S. Department of Commerce that finds and writes regulations for today’s encryption schemes.

The team modified the number theoretic transform (NTT) technique for the circuit design. NTT is similar to the Fourier transform mathematical technique, which decomposes a signal into the multiple frequencies that compose it.

“We basically modified how the vector is physically mapped in the memory and modified the data flow, so this new mapping can be incorporated into the sampling process. Using these architecture tricks, we reduced the energy consumption and occupied area, while maintaining the desired throughput,” Banerjee says.

The team’s work was supported by Texas Instruments and the TSMC University Shuttle Program.

Changing how lithium-ion batteries are recycled
Electric vehicles promise to reduce greenhouse gas emissions and make for greener personal transportation. In the near future at least, those EVs will be running on lithium-ion batteries. One issue that must be resolved: The recycling of EV batteries, which are larger than the AA and AAA batteries used in consumer electronics.

In a paper published in the Nature Sustainability journal, Jay Whitacre, director of Carnegie Mellon University’s Wilton E. Scott Institute for Energy Innovation and professor of Materials Science and Engineering and Engineering and Public Policy, and Rebecca Ciez have laid out a path forward for battery makers and policymakers alike to help ensure that this influx of lithium-ion batteries doesn’t undo the good work of electric vehicles.

“Automakers are also interested in recycling as a potential source of low-cost material that can be remanufactured into new battery packs,” said Ciez, a postdoctoral fellow at Princeton University and a former student of Whitacre.

The researchers examined how a direct cathode recycling process would compare to other recycling processes in terms of GHGs and energy consumption. This method of battery recycling is focused on keeping the cathode materials intact so they can be used in future batteries. While all lithium-ion batteries use lithium to carry the charge, their cathodes — which store the lithium ions when the battery is discharged — can be made out of a variety of materials, such as nickel, manganese, or cobalt.

“We focused our analysis on specific lithium-ion formulations that are most common in today’s electric vehicles,” Ciez said, “and found that for cathodes containing metals like nickel, manganese, and cobalt, direct cathode recycling can reduce the greenhouse gas emissions associated with manufacturing new batteries from the materials and has the potential to be economically competitive with traditional cathode manufacturing.”

The implementation of recycling processes is mandated by policy, and according to Whitacre and Ciez, policies for lithium-ion battery recycling must encourage collection of automotive lithium-ion batteries and mandate that recycling processes offer net reductions in greenhouse gas emissions, rather than focusing on the percentage of battery content that is recycled.

The use of drones in precision agriculture
Marwan Madi became interested in precision agriculture technology and how unmanned aerial vehicles could be used to detect the health or stress of vegetation while he was a high school senior in Sugar Land, Texas, near Houston. Marwan is now an engineering junior, in the 2020 class for the University of Texas at Austin.

He is also a co-founder of Maverick Labs, a drone services startup. UT is allowing Marwan and his business partner to try out their drone technology on the lawn in front of the LBJ Library, the thirstiest part of the Austin campus.

These drones use multispectral sensors that calculate the ratio of visible light to near-infrared light. This sophisticated sensor can even detect weeds and tell the farmer what kind of weeds they are. What Maverick Labs provides is the coordinated service and provisioning needed to operate the drones.

“Not only do you have to purchase the drone, you have to purchase the software and the sensor, and have an FAA certification,” Marwan notes. He adds, “What we’re predicting and what the data show so far is we are going to be able to save farmers a lot of money on chemicals and fertilizers as well as water. Margins are very small in farming. They need all the help they can get.” The margins are small, but the economic impact to Texas of the food and fiber sector totals more than $100 billion annually.

“It’s been a great experience so far, and I’m looking forward to what we can do with this new service,” Marwan concludes.

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