Computers Math

“Image” is everything in the $20 billion market for AR/VR glasses. Consumers are looking for glasses that are compact and easy to wear, delivering high-quality imagery with socially acceptable optics that don’t look like “bug eyes.”
University of Rochester researchers at the Institute of Optics have come up with a novel technology to deliver those attributes with maximum effect. In a paper in Science Advances, they describe imprinting freeform optics with a nanophotonic optical element called “a metasurface.”
The metasurface is a veritable forest of tiny, silver, nanoscale structures on a thin metallic film that conforms, in this advance, to the freeform shape of the optics — realizing a new optical component the researchers call a metaform.
The metaform is able to defy the conventional laws of reflection, gathering the visible light rays entering an AR/VR eyepiece from all directions, and redirecting them directly into the human eye.
Nick Vamivakas, a professor of quantum optics and quantum physics, likened the nanoscale structures to small-scale radio antennas. “When we actuate the device and illuminate it with the right wavelength, all of these antennas start oscillating, radiating a new light that delivers the image we want downstream.”
“Metasurfaces are also called ‘flat optics’ so writing metasurfaces on freeform optics is creating an entirely new type of optical component,” says Jannick Rolland, the Brian J. Thompson Professor of Optical Engineering and director of the Center for Freeform Optics. More

According to Michael Twidale, professor in the School of Information Sciences at the University of Illinois Urbana-Champaign, bad usability can be an irritation for everyone but “especially awful” for the underprivileged. In “Everyone Everywhere: A Distributed and Embedded Paradigm for Usability,” which was recently published in the Journal of the Association for Information Science and Technology (JASIST), Twidale and coauthors David M. Nichols (University of Waikato, New Zealand) and Christopher P. Lueg (Bern University of Applied Sciences, Switzerland) present a new paradigm to address the persistence of difficulties that people have in accessing and using information.
Twidale points to the COVID vaccination rollout as one recent example of bad usability. In many places, people have to book their vaccine appointments online, which can be difficult for the especially vulnerable elderly population.
“When hard to use software means a vulnerable elderly person cannot book a vaccination, that’s a social justice issue,” he said. “If you can’t get things to work, it can further exclude you from the benefits that technology is bringing to everyone else. Making a computer system easier to use is a tiny fraction of the cost of making the computer system work at all. So why aren’t things fixed? Because people put up with bad interfaces and blame themselves. We want to say, ‘No, it’s not your fault! It is bad design.'”
Twidale and his coauthors propose expanding awareness of usability and distributing the topic across disciplines, beyond the “tiny elite” of usability professions. In turn, this increased emphasis on usability could lead to improvements in other disciplines such as politics (e.g., better ballot design) and medicine (e.g., user-friendly medical devices).
“A wider usability movement would remind members of any profession that regardless of their domain and efforts in making the world a better place, bad usability makes everything worse. In contrast, reducing bad usability is often a relatively low-cost way of contributing to improvements within these professions.”
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Materials provided by University of Illinois School of Information Sciences. Note: Content may be edited for style and length. More

In 2018, industry and academic researchers revealed a potentially devastating hardware flaw that made computers and other devices worldwide vulnerable to attack.
Researchers named the vulnerability Spectre because the flaw was built into modern computer processors that get their speed from a technique called “speculative execution,” in which the processor predicts instructions it might end up executing and preps by following the predicted path to pull the instructions from memory. A Spectre attack tricks the processor into executing instructions along the wrong path. Even though the processor recovers and correctly completes its task, hackers can access confidential data while the processor is heading the wrong way.
Since Spectre was discovered, the world’s most talented computer scientists from industry and academia have worked on software patches and hardware defenses, confident they’ve been able to protect the most vulnerable points in the speculative execution process without slowing down computing speeds too much.
They will have to go back to the drawing board.
A team of University of Virginia School of Engineering computer science researchers has uncovered a line of attack that breaks all Spectre defenses, meaning that billions of computers and other devices across the globe are just as vulnerable today as they were when Spectre was first announced. The team reported its discovery to international chip makers in April and will present the new challenge at a worldwide computing architecture conference in June.
The researchers, led by Ashish Venkat, William Wulf Career Enhancement Assistant Professor of Computer Science at UVA Engineering, found a whole new way for hackers to exploit something called a “micro-op cache,” which speeds up computing by storing simple commands and allowing the processor to fetch them quickly and early in the speculative execution process. Micro-op caches have been built into Intel computers manufactured since 2011. More

Researchers have developed a brain-like computing device that is capable of learning by association.
Similar to how famed physiologist Ivan Pavlov conditioned dogs to associate a bell with food, researchers at Northwestern University and the University of Hong Kong successfully conditioned their circuit to associate light with pressure.
The research will be published April 30 in the journal Nature Communications.
The device’s secret lies within its novel organic, electrochemical “synaptic transistors,” which simultaneously process and store information just like the human brain. The researchers demonstrated that the transistor can mimic the short-term and long-term plasticity of synapses in the human brain, building on memories to learn over time.
With its brain-like ability, the novel transistor and circuit could potentially overcome the limitations of traditional computing, including their energy-sapping hardware and limited ability to perform multiple tasks at the same time. The brain-like device also has higher fault tolerance, continuing to operate smoothly even when some components fail.
“Although the modern computer is outstanding, the human brain can easily outperform it in some complex and unstructured tasks, such as pattern recognition, motor control and multisensory integration,” said Northwestern’s Jonathan Rivnay, a senior author of the study. “This is thanks to the plasticity of the synapse, which is the basic building block of the brain’s computational power. These synapses enable the brain to work in a highly parallel, fault tolerant and energy-efficient manner. In our work, we demonstrate an organic, plastic transistor that mimics key functions of a biological synapse.”
Rivnay is an assistant professor of biomedical engineering at Northwestern’s McCormick School of Engineering. He co-led the study with Paddy Chan, an associate professor of mechanical engineering at the University of Hong Kong. Xudong Ji, a postdoctoral researcher in Rivnay’s group, is the paper’s first author. More

Tomorrow’s cutting-edge technology will need electronics that can tolerate extreme conditions. That’s why a group of researchers led by Michigan State University’s Jason Nicholas is building stronger circuits today.
Nicholas and his team have developed more heat resilient silver circuitry with an assist from nickel. The team described the work, which was funded by the U.S. Department of Energy Solid Oxide Fuel Cell Program, on April 15 in the journal Scripta Materialia.
The types of devices that the MSU team is working to benefit — next-generation fuel cells, high-temperature semiconductors and solid oxide electrolysis cells — could have applications in the auto, energy and aerospace industries.
Although you can’t buy these devices off the shelf now, researchers are currently building them in labs to test in the real world, and even on other planets.
For example, NASA developed a solid oxide electrolysis cell that enabled the Mars 2020 Perseverance Rover to make oxygen from gas in the Martian atmosphere on April 22. NASA hopes this prototype will one day lead to equipment that allows astronauts to create rocket fuel and breathable air while on Mars.
To help such prototypes become commercial products, though, they’ll need to maintain their performance at high temperatures over long periods of time, said Nicholas, an associate professor in the College of Engineering. More

The field of soft robotics has exploded in the past decade, as ever more researchers seek to make real the potential of these pliant, flexible automata in a variety of realms, including search and rescue, exploration and medicine.
For all the excitement surrounding these new machines, however, UC Santa Barbara mechanical engineering professor Elliot Hawkes wants to ensure that soft robotics research is more than just a flash in the pan. “Some new, rapidly growing fields never take root, while others become thriving disciplines,” Hawkes said.
To help guarantee the longevity of soft robotics research, Hawkes, whose own robots have garnered interest for their bioinspired and novel locomotion and for the new possibilities they present, offers an approach that moves the field forward. His viewpoint, written with colleagues Carmel Majidi from Carnegie Mellon University and Michael T. Tolley of UC San Diego, is published in the journal Science Robotics.
“We were looking at publication data for soft robotics and noticed a phase of explosive growth over the last decade,” Hawkes said. “We became curious about trends like this in new fields, and how new fields take root.”
The first decade of widespread soft robotics research, according to the group, “was characterized by defining, inspiring and exploring,” as roboticists took to heart what it meant to create a soft robot, from materials systems to novel ways of navigating through and interacting with the environment.
However, the researchers argue, “for soft robotics to become a thriving, impactful field in the next decade, every study must make a meaningful contribution.” According to Hawkes, the long-term duration of a rapidly growing field is often a matter of whether the initial exploratory research matures. More

The Mayo Clinic data scientists who developed highly accurate computer modeling to predict trends for COVID-19 cases nationwide have new research that shows how important a high rate of vaccination is to reducing case numbers and controlling the pandemic.
Vaccination is making a striking difference in Minnesota and keeping the current level of positive cases from becoming an emergency that overwhelms ICUs and leads to more illness and death, according to a study published in Mayo Clinic Proceedings. The study, entitled “Quantifying the Importance of COVID-19 Vaccination to Our Future Outlook,” outlines how Mayo’s COVID-19 predictive modeling can assess future trends based on the pace of vaccination, and how vaccination trends are crucial to the future course of the pandemic.
The Mayo researchers estimate that a peak of more than 800 patients would be in hospital ICUs in Minnesota this spring if no vaccines had been developed. The projections take into account new variants of the SARS-CoV-2 virus as well as current public health measures and masking standards.
The predicted ICU census levels would be more than double the number of Minnesota COVID-19 patients who were hospitalized in ICUs on Dec. 1, at the height of the most recent surge last year.
“It is difficult to untangle how much of this elevated rate of spread right now is due to new variants as opposed to changes in social behavior,” the authors say, but “regardless of the reason, the absence of vaccinations in the current environment would have been likely to result in by far the largest surge to date.”
If Minnesota had achieved vaccination of 75% of the population by early April, the study estimates that the 7-day average of cases per 100,000 residents, the number of COVID-19 patients hospitalized and the number in ICUs would plummet by early July. “According to the model, this level of vaccination would completely suppress the growth (even in the face of the recent elevated spread rate) and immediately drive cases and hospitalizations down to very low levels,” the authors say.
The Mayo Clinic study was led by Curtis Storlie, Ph.D., and Sean Dowdy, M.D., whose team developed the computer model for forecasting COVID-19’s impact on hospital usage that has helped guide Mayo’s response to the pandemic. Mayo Clinic’s predictive modeling also has been shared with Minnesota public health leadership to help inform critical decisions over the past year.
Mayo Clinic’s forecasting of COVID-19 trends nationally is available online at the Mayo Clinic COVID-19 Resource Center (https://www.mayoclinic.org/coronavirus-covid-19). The Coronavirus Map tracking tool has county-by-county information on COVID-19 cases and trends nationwide.
When the pandemic emerged last year, Mayo Clinic data scientists developed predictive modeling to assess when and where COVID-19 hot spots would occur. The model accurately predicted the timing and magnitude of COVID-19 case and hospitalization surges, which enabled Mayo Clinic to prepare and assure it could provide the best care while keeping patients and staff safe.
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Materials provided by Mayo Clinic. Original written by Jay Furst. Note: Content may be edited for style and length. More

Although robotic devices are used in everything from assembly lines to medicine, engineers have a hard time accounting for the friction that occurs when those robots grip objects — particularly in wet environments. Researchers have now discovered a new law of physics that accounts for this type of friction, which should advance a wide range of robotic technologies.
“Our work here opens the door to creating more reliable and functional haptic and robotic devices in applications such as telesurgery and manufacturing,” says Lilian Hsiao, an assistant professor of chemical and biomolecular engineering at North Carolina State University and corresponding author of a paper on the work.
At issue is something called elastohydrodynamic lubrication (EHL) friction, which is the friction that occurs when two solid surfaces come into contact with a thin layer of fluid between them. This would include the friction that occurs when you rub your fingertips together, with the fluid being the thin layer of naturally occurring oil on your skin. But it could also apply to a robotic claw lifting an object that has been coated with oil, or to a surgical device that is being used inside the human body.
One reason friction is important is because it helps us hold things without dropping them.
“Understanding friction is intuitive for humans — even when we’re handling soapy dishes,” Hsiao says. “But it is extremely difficult to account for EHL friction when developing materials that controls grasping capabilities in robots.”
To develop materials that help control EHL friction, engineers would need a framework that can be applied uniformly to a wide variety of patterns, materials and dynamic operating conditions. And that is exactly what the researchers have discovered.
“This law can be used to account for EHL friction, and can be applied to many different soft systems — as long as the surfaces of the objects are patterned,” Hsiao says.
In this context, surface patterns could be anything from the slightly raised surfaces on the tips of our fingers to grooves in the surface of a robotic tool.
The new physical principle, developed jointly by Hsiao and her graduate student Yunhu Peng, makes use of four equations to account for all of the physical forces at play in understanding EHL friction. In the paper, the research team demonstrated the law in three systems: human fingers; a bio-inspired robotic fingertip; and a tool called a tribo-rheometer, which is used to measure frictional forces. Peng is first author of the paper.
“These results are very useful in robotic hands that have more nuanced controls for reliably handling manufacturing processes,” Hsiao says. “And it has obvious applications in the realm of telesurgery, in which surgeons remotely control robotic devices to perform surgical procedures. We view this as a fundamental advancement for understanding touch and for controlling touch in synthetic systems.”
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Materials provided by North Carolina State University. Note: Content may be edited for style and length. More