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    AI system-on-chip runs on solar power

    AI is used in an array of extremely useful applications, such as predicting a machine’s lifetime through its vibrations, monitoring the cardiac activity of patients and incorporating facial recognition capabilities into video surveillance systems. The downside is that AI-based technology generally requires a lot of power and, in most cases, must be permanently connected to the cloud, raising issues related to data protection, IT security and energy use.
    CSEM engineers may have found a way to get around those issues, thanks to a new system-on-chip they have developed. It runs on a tiny battery or a small solar cell and executes AI operations at the edge — i.e., locally on the chip rather than in the cloud. What’s more, their system is fully modular and can be tailored to any application where real-time signal and image processing is required, especially when sensitive data are involved. The engineers will present their device at the prestigious 2021 VLSI Circuits Symposium in Kyoto this June.
    The CSEM system-on-chip works through an entirely new signal processing architecture that minimizes the amount of power needed. It consists of an ASIC chip with a RISC-V processor (also developed at CSEM) and two tightly coupled machine-learning accelerators: one for face detection, for example, and one for classification. The first is a binary decision tree (BDT) engine that can perform simple tasks but cannot carry out recognition operations.
    “When our system is used in facial recognition applications, for example, the first accelerator will answer preliminary questions like: Are there people in the images? And if so, are their faces visible?” says Stéphane Emery, head of system-on-chip research at CSEM. “If our system is used in voice recognition, the first accelerator will determine whether noise is present and if that noise corresponds to human voices. But it can’t make out specific voices or words — that’s where the second accelerator comes in.”
    The second accelerator is a convolutional neural network (CNN) engine that can perform these more complicated tasks — recognizing individual faces and detecting specific words — but it also consumes more energy. This two-tiered data processing approach drastically reduces the system’s power requirement, since most of the time only the first accelerator is running.
    As part of their research, the engineers enhanced the performance of the accelerators themselves, making them adaptable to any application where time-based signal and image processing is needed. “Our system works in basically the same way regardless of the application,” says Emery. “We just have to reconfigure the various layers of our CNN engine.”
    The CSEM innovation opens the door to an entirely new generation of devices with processors that can run independently for over a year. It also sharply reduces the installation and maintenance costs for such devices, and enables them to be used in places where it would be hard to change the battery.
    Video: https://www.youtube.com/watch?v=2wJi4BHdXGo&t=2s
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    Materials provided by Swiss Center for Electronics and Microtechnology – CSEM. Note: Content may be edited for style and length. More

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    New invention keeps qubits of light stable at room temperature

    As almost all our private information is digitalized, it is increasingly important that we find ways to protect our data and ourselves from being hacked.
    Quantum Cryptography is the researchers’ answer to this problem, and more specifically a certain kind of qubit — consisting of single photons: particles of light.
    Single photons or qubits of light, as they are also called, are extremely difficult to hack.
    However, in order for these qubits of light to be stable and work properly they need to be stored at temperatures close to absolute zero — that is minus 270 C — something that requires huge amounts of power and resources.
    Yet in a recently published study, researchers from University of Copenhagen, demonstrate a new way to store these qubits at room temperature for a hundred times longer than ever shown before.
    “We have developed a special coating for our memory chips that helps the quantum bits of light to be identical and stable while being in room temperature. In addition, our new method enables us to store the qubits for a much longer time, which is milliseconds instead of microseconds — something that has not been possible before. We are really excited about it,” says Eugene Simon Polzik, professor in quantum optics at the Niels Bohr Institute. More

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    A new book uses stories from tsunami survivors to decode deadly waves

    TsunamiJames Goff and Walter DudleyOxford Univ., $34.95

    On March 27, 1964, Ted Pederson was helping load oil onto a tanker in Seward, Alaska, when a magnitude 9.2 quake struck. Within seconds, the waterfront began sliding into the bay. As Pederson ran up the dock toward shore, a tsunami lifted the tanker and rafts of debris onto the dock, knocking him unconscious.

    Pederson survived, but more than 100 others in Alaska did not. His story is just one of more than 400 harrowing eyewitness accounts that bring such disasters to life in Tsunami. Written by geologist James Goff and oceanographer Walter Dudley, the book also weaves in accounts from researchers examining the geologic record to shed light on prehistoric tsunamis.

    Chapter by chapter, Goff and Dudley offer readers a primer on tsunamis: Most are caused by undersea earthquakes, but some are triggered by landslides, the sudden collapse of volcanic islands or meteorites hitting the ocean (SN: 3/6/04, p. 152). Readers may be surprised to learn that tsunamis need not occur on the coast: Lake Tahoe (SN: 6/10/00, p. 378) and New Zealand’s Lake Tarawera are just two of many inland locales mentioned that have experienced freshwater tsunamis.

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    Copiously illustrated and peppered with maps, the book takes readers on a world-spanning tour of ancient and recent tsunamis, from a deep-ocean impact off the coast of South America about 2.5 million years ago to numerous tsunamis of the 21st century. The authors’ somber treatment of the Indian Ocean tsunami of December 2004 stands out (SN: 1/8/05, p. 19). Triggered by a magnitude 9.1 earthquake, the megawave killed more than 130,000 people in Indonesia alone.

    The authors — Goff is a professor at the University of New South Wales in Sydney and Dudley is a researcher at the University of Hawaii at Hilo — help readers understand tsunamis’ power via descriptions of the damage they’ve wrought. For instance, the account of a huge wave in Alaska that scoured mature trees from steep slopes along fjords up to a height of 524 meters — about 100 meters taller than the Empire State Building — may leave readers stunned. But it’s the heart-thumping stories of survivors who ran to high ground, clambered up tall trees or clung to debris after washing out to sea that linger with the reader. They remind us of the human cost of living on the shore when great waves strike.

    Buy Tsunami from Bookshop.org. Science News is a Bookshop.org affiliate and will earn a commission on purchases made from links in this article. More

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    Researchers uncover unique properties of a promising new superconductor

    An international team of physicists led by the University of Minnesota has discovered that a unique superconducting metal is more resilient when used as a very thin layer. The research is the first step toward a larger goal of understanding unconventional superconducting states in materials, which could possibly be used in quantum computing in the future.
    The collaboration includes four faculty members in the University of Minnesota’s School of Physics and Astronomy — Associate Professor Vlad Pribiag, Professor Rafael Fernandes, and Assistant Professors Fiona Burnell and Ke Wang — along with physicists at Cornell University and several other institutions. The study is published in Nature Physics, a monthly, peer-reviewed scientific journal published by the Nature Research.
    Niobium diselenide (NbSe2) is a superconducting metal, meaning that it can conduct electricity, or transport electrons from one atom to another, with no resistance. It is not uncommon for materials to behave differently when they are at a very small size, but NbSe2 has potentially beneficial properties. The researchers found that the material in 2D form (a very thin substrate only a few atomic layers thick) is a more resilient superconductor because it has a two-fold symmetry, which is very different from thicker samples of the same material.
    Motivated by Fernandes and Burnell’s theoretical prediction of exotic superconductivity in this 2D material, Pribiag and Wang started to investigate atomically-thin 2D superconducting devices.
    “We expected it to have a six-fold rotational pattern, like a snowflake.” Wang said. “Despite the six-fold structure, it only showed two-fold behavior in the experiment.”
    “This was one of the first times [this phenomenon] was seen in a real material,” Pribiag said.
    The researchers attributed the newly-discovered two-fold rotational symmetry of the superconducting state in NbSe2 to the mixing between two closely competing types of superconductivity, namely the conventional s-wave type — typical of bulk NbSe2 — and an unconventional d- or p-type mechanism that emerges in few-layer NbSe2. The two types of superconductivity have very similar energies in this system. Because of this, they interact and compete with each other.
    Pribiag and Wang said they later became aware that physicists at Cornell University were reviewing the same physics using a different experimental technique, namely quantum tunneling measurements. They decided to combine their results with the Cornell research and publish a comprehensive study.
    Burnell, Pribiag, and Wang plan to build on these initial results to further investigate the properties of atomically thin NbSe2 in combination with other exotic 2D materials, which could ultimately lead to the use of unconventional superconducting states, such as topological superconductivity, to build quantum computers.
    “What we want is a completely flat interface on the atomic scale,” Pribiag said. “We believe this system will be able to give us a better platform to study materials to use them for quantum computing applications.”
    In addition to Pribiag, Fernandes, Burnell, Wang, the collaboration included University of Minnesota physics graduate students Alex Hamill, Brett Heischmidt, Daniel Shaffer, Kan-Ting Tsai, and Xi Zhang; Cornell University faculty members Jie Shan and Kin Fai Mak and graduate student Egon Sohn; Helmuth Berger and László Forró, researchers at Ecole Polytechnique Fédérale de Lausanne in Switzerland; Alexey Suslov, a researcher at the National High Magnetic Field Laboratory in Tallahassee, Fla.; and Xiaoxiang Xi, a professor at Nanjing University in China.
    The University of Minnesota research was supported primarily by the National Science Foundation (NSF) through the University of Minnesota Materials Research Science and Engineering Center (MRSEC). The research at Cornell was supported by the Office of Naval Research (ONR) and NSF. The work in Switzerland was supported by the Swiss National Science Foundation.
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    Computers predict people's tastes in art

    Do you like the thick brush strokes and soft color palettes of an impressionist painting such as those by Claude Monet? Or do you prefer the bold colors and abstract shapes of a Rothko? Individual art tastes have a certain mystique to them, but now a new Caltech study shows that a simple computer program can accurately predict which paintings a person will like.
    The new study, appearing in the journal Nature Human Behaviour, utilized Amazon’s crowdsourcing platform Mechanical Turk to enlist more than 1,500 volunteers to rate paintings in the genres of impressionism, cubism, abstract, and color field. The volunteers’ answers were fed into a computer program and then, after this training period, the computer could predict the volunteers’ art preferences much better than would happen by chance.
    “I used to think the evaluation of art was personal and subjective, so I was surprised by this result,” says lead author Kiyohito Iigaya, a postdoctoral scholar who works in the laboratory of Caltech professor of psychology John O’Doherty.
    The findings not only demonstrated that computers can make these predictions but also led to a new understanding about how people judge art.
    “The main point is that we are gaining an insight into the mechanism that people use to make aesthetic judgments,” says O’Doherty. “That is, that people appear to use elementary image features and combine over them. That’s a first step to understanding how the process works.”
    In the study, the team programmed the computer to break a painting’s visual attributes down into what they called low-level features — traits like contrast, saturation, and hue — as well as high-level features, which require human judgment and include traits such as whether the painting is dynamic or still. More

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    Inducing and tuning spin interactions in layered material

    Magnetic-spin interactions that allow spin-manipulation by electrical control allow potential applications in energy-efficient spintronic devices.
    An antisymmetric exchange known as Dzyaloshinskii-Moriya interactions (DMI) is vital to form various chiral spin textures, such as skyrmions, and permits their potential application in energy-efficient spintronic devices.
    Published this week, a Chinese-Australia collaboration has for the first time illustrated that DMI can be induced in a layered material tantalum-sulfide (TaS2) by intercalating iron atoms, and can further be tuned by gate-induced proton intercalation.
    REALIZING AND TUNING DMI IN VAN-DER-WAALS MATERIAL TaS2
    Searching for layered materials that harbour chiral spin textures, such as skyrmions, chiral domain Walls is vital for further low-energy nanodevices, as those chiral spin textures are building blocks for topological spintronic devices and can be driven by ultra-low current density.
    Generally, chiral spin textures are stabilized by DMI. Therefore, introducing and controlling DMI in materials is key in searching and manipulating the chiral spin textures. More

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    Electrohydraulic arachno-bot a fascinating lightweight

    It is not the first time that spiders have served as biological models in the research field of soft robotics. The hydraulic actuation mechanisms they apply to move their limbs when weaving their web or hunting for prey give them powers many roboticists and engineers have drawn inspiration from.
    A team of researchers at the Max Planck Institute for Intelligent Systems in Germany and at the University of Boulder in Colorado in the US has now found a new way to exploit the principles of spiders’ joints to drive articulated robots without any bulky components and connectors, which weigh down the robot and reduce portability and speed. Their slender and lightweight simple structures impress by enabling a robot to jump 10 times its height. At the end of May, the team’s work titled “Spider-inspired electrohydraulic actuators for fast, soft-actuated joints” was published in Advanced Science.
    The high performance is enabled by Spider-inspired Electrohydraulic Soft-actuated joints — SES joints in short. The joints can be used in many different configurations — not just when creating an arachno-bot. In their paper, the scientists demonstrate a bidirectional joint, a multi-segmented artificial limb, and a three-fingered gripper, which can easily pick up delicate objects. All creations are lightweight, simple in their design, and exhibit high performance making them ideal for robotic systems that need to move rapidly and interact with many different environments.
    The researchers developed their SES joints based on the HASEL technology which had previously been invented by the team to build artificial muscles. SES joints mimic a spider-inspired exoskeletal mechanism comprised of both rigid and softer elements, which function similarly to the animal’s leg extension through the use of hydraulic forces.
    They built a flexible pouch made of thin plastic films (either polyester or polypropylene will do) which they filled with a liquid dielectric — a vegetable-based oil. They then placed electrodes on each side of the pouch. These liquid-filled pockets serve as actuators, in which the hydraulic power is generated through electrostatic forces. The pouch is attached to a rotary joint. When a high voltage is applied between the electrodes, the electrostatic forces cause the liquid dielectric to shift inside the pouch and the joint to flex. SES joints are capable of rotating up to 70 degrees, causing high torques, and can easily restore back to the starting position.
    “The SES joints are very simple and light, as there are no peripheral components which weigh down the robot,” says Christoph Keplinger, Director of the Robotic Materials Department at the Max Planck Institute for Intelligence Systems. “Many applications for soft robots require versatile actuators. These spider-inspired joints allow for high functionality and consume only little power, they are easy and cheap to make — the plastics we are using are for food packaging — and their production is easily scalable. These are all qualities that are critical for the design of robots, which can move in many different ways and manipulate a variety of objects without breaking them.”
    A three-fingered gripper was one application for which the team used SES joints to showcase their versatility. If the team had equipped the gripper with a muscle-like structure, it would have been in the way of the object that the gripper is grabbing. Using SES joints as the hinges of the gripper required much less space.
    “The research stands out because we can use a wide variety of materials, even the plastic used to make chips bags to create the pouches,” the first author of the publication Nicholas Kellaris says. “That way we can implement SES in a wide variety of geometries with specifically tuned actuation characteristics.”
    “The ultimate goal of our research was not to make a spider robot,” Philipp Rothemund, the second author of the publication, adds. “We wanted to develop a state-of-the-art, active joint that you can put in any type of robot.”
    Especially for small-scale robotic systems of only a few centimeters in size, where the limited space severely restricts the choice of actuator technologies, the SES-joints will come in very useful. For the soft robotics community, this invention is truly a leap forward.
    Video: https://www.youtube.com/watch?v=XtZSv7ZcoxY More

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    Bruisable artificial skin could help prosthetics, robots sense injuries

    When someone bumps their elbow against a wall, they not only feel pain but also might experience bruising. Robots and prosthetic limbs don’t have these warning signs, which could lead to further injury. Now, researchers reporting in ACS Applied Materials & Interfaces have developed an artificial skin that senses force through ionic signals and also changes color from yellow to a bruise-like purple, providing a visual cue that damage has occurred.
    Scientists have developed many different types of electronic skins, or e-skins, that can sense stimuli through electron transmission. However, these electrical conductors are not always biocompatible, which could limit their use in some types of prosthetics. In contrast, ionic skins, or I-skins, use ions as charge carriers, similar to human skin. These ionically conductive hydrogels have superior transparency, stretchability and biocompatibility compared with e-skins. Qi Zhang, Shiping Zhu and colleagues wanted to develop an I-skin that, in addition to registering changes in electrical signal with an applied force, could also change color to mimic human bruising.
    The researchers made an ionic organohydrogel that contained a molecule, called spiropyran, that changes color from pale yellow to bluish-purple under mechanical stress. In testing, the gel showed changes in color and electrical conductivity when stretched or compressed, and the purple color remained for 2-5 hours before fading back to yellow. Then, the team taped the I-skin to different body parts of volunteers, such as the finger, hand and knee. Bending or stretching caused a change in the electrical signal but not bruising, just like human skin. However, forceful and repeated pressing, hitting and pinching produced a color change. The I-skin, which responds like human skin in terms of electrical and optical signaling, opens up new opportunities for detecting damage in prosthetic devices and robotics, the researchers say.
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