Computers Math

Imagine you can open your fridge, open an app on your phone and immediately know which items are expiring within a few days. This is one of the applications that a new technology developed by engineers at the University of California San Diego would enable.
The technology combines a chip integrated into product packaging and a software update on your phone. The phone becomes capable of identifying objects based on signals the chip emits from specific frequencies, in this case Bluetooth or WiFi. In an industrial setting, a smartphone equipped with the software update could be used as an RFID reader.
The work harnesses breakthroughs in backscatter communication, which uses signals already generated by your smartphone and re-directs them back in a format your phone can understand. Effectively, this technique uses 1000 less power than state of the art to generate WiFi signals These advances have enabled very low-power communication between components of the Internet of Things and hardware such as WiFi or Bluetooth transceivers, for applications such as on-body sensors or asset trackers.
The custom chip, which is roughly the size of a grain of sand and costs only a few pennies to manufacture, needs so little power that it can be entirely powered by LTE signals, a technique called RF energy harvesting. The chip turns Bluetooth transmissions into WiFi signals, which can in turn be detected by a smartphone with that specific software update.
The team will present their work at the IEEE International Solid-State Circuits Conference in San Francisco on Feb. 20, 2023.
Currently, state of the art backscatter modulation requires two external devices: one to transmit and one to receive and read the signals. This conference paper presents the first backscatter integrated circuit that can enable wireless communication and battery-less operation coming from a single mobile device.

“This approach enables a robust, low-cost and scalable way to provide power and enable communications in an RFID-like manner, while using smartphones as the devices that both read and power the signals,” said Patrick Mercier, one of the paper’s senior authors and a professor in the Department of Electrical and Computer Engineering at the University of California San Diego.
The technology’s broader promise is the development of devices that do not need batteries because they can harvest power from LTE signals instead. This in turn would lead to devices that are significantly less expensive, last longer, up to several decades, said Dinesh Bharadia, a professor in the UC San Diego Department of Electrical and Computer Engineering and one of the paper’s senior authors.
“E-waste, especially batteries, is one of the biggest problems the planet is facing, after climate change,” Bharadia said.
How it works
The researchers achieved this breakthrough by harvesting power from LTE smartphone signals and buffering this power onto an energy storage capacitor. This in turn activates a receiver that detects Bluetooth signals, which are then modified into reflected WiFi signals.

The software update is simply a bit sequence that turns the Bluetooth signal into something that can be more easily turned into a WiFi signal.
In addition, most lower power wireless communications require custom protocols, but the device the researchers developed relies on common communication protocols: Bluetooth, WiFi and LTE. That’s because smartphones are equipped with both a Bluetooth transmitter and a WiFi receiver.
The device has a range of one meter-about one yard. Adding a battery would boost the tag’s range to tens of meters, but also increase costs. The device, which is half a square inch in size, costs just a few cents to manufacture.
Next steps
Next steps include integrating the technology in other research projects to demonstrate its capabilities.
The team also hopes to commercialize the device, either through a startup or through an industry partner.
The work was supported by the National Science Foundation under Grant 1923902 and the UC San Diego Center for Wearable Sensors.
An LTE-harvesting BLE-to-WiFi Backscattering Chip for Single-Device RFID-like Interrogation
Shih-Jai Kuo*, Manideep Dunna*, Hongyu Lu, Akshit Agarwal, Dinesh Bharadia, Patrick Mercier, Department of Electrical and Computer Engineering, University of California San Diego
*co-primary authors More

In recent years, wearable devices such as smartwatches and rings, as well as smart scales, have become ubiquitous — “must-haves” for the health conscious to self-monitor heart rate, blood pressure, and other vital signs. Despite the obvious benefits, certain fitness and wellness trackers could also pose serious risks for people with cardiac implantable electronic devices (CIEDs) such as pacemakers, implantable cardioverter defibrillators (ICDs), and cardiac resynchronization therapy (CRT) devices, reports a new study published in Heart Rhythm, the official journal of the Heart Rhythm Society, the Cardiac Electrophysiology Society, and the Pediatric & Congenital Electrophysiology Society, published by Elsevier.
Investigators evaluated the functioning of CRT devices from three leading manufacturers while applying electrical current used during bioimpedance sensing. Bioimpedance sensing is a technology that emits a very small, imperceptible current of electricity (measured in microamps) into the body. The electrical current flows through the body, and the response is measured by the sensor to determine the person’s body composition (i.e., skeletal muscle mass or fat mass), level of stress, or vital signs, such as breathing rate.
“Bioimpedance sensing generated an electrical interference that exceeded Food and Drug Administration-accepted guidelines and interfered with proper CIED functioning,” explained lead investigator Benjamin Sanchez Terrones, PhD, Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT, USA. He emphasized that the results, determined through careful simulations and benchtop testing, do not convey an immediate or clear risk to patients who wear the trackers, but noted that the different levels emitted could result in pacing interruptions or unnecessary shocks to the heart. Dr. Sanchez added, “our findings call for future clinical studies examining patients with CIEDs and wearables.”
The interaction between general electrical appliances, and more recently smart phones, with CIEDs has been subject to study within the scientific community over the past few years. Nearly all, if not all, implantable cardiac devices already warn patients about the potential for interference with a variety of electronics due to magnetic fields — for example, carrying a mobile phone in your breast pocket near a pacemaker. The rise of wearable health tech has grown rapidly in recent years, blurring the line between medical and consumer devices. Until this study, objective evaluation for ensuring safety has not kept pace with the exciting new gadgets.
“Our research is the first to study devices that employ bioimpedance-sensing technology as well as discover potential interference problems with CIEDs such as CRT devices. We need to test across a broader cohort of devices and in patients with these devices. Collaborative investigation between researchers and industry would be helpful for keeping patients safe,” noted Dr. Sanchez Terrones. More

A database updated in 2022 reported around 4,852 active satellites orbiting the earth. These satellites serve many different purposes in space, from GPS and weather tracking to military reconnaissance and early warning systems. Given the wide array of uses for satellites, especially in low Earth orbit (LEO), researchers are constantly trying to develop better ones. In this regard, small satellites have a lot of potential. They can reduce launch costs and increase the number of satellites in orbit, providing a better network with wider coverage. However, due to their smaller size, these satellites have lesser radiation shield. They also have a deployable membrane attached to the main body for a large phased-array transceiver, which causes non-uniform radiation degradation across the transceiver. This affects the performance of the satellite’s radio due to the variation in the strength of signal they can sense — also known as gain variation. Thus, there is a need to mitigate radiation degradation to make small satellites more viable.

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Engineering researchers at the University of Waterloo are successfully using a robot to help keep children with learning disabilities focused on their work.
This was one of the key results in a new study that also found both the youngsters and their instructors valued the positive classroom contributions made by the robot.
“There is definitely a great potential for using robots in the public education system,” said Dr. Kerstin Dautenhahn, a professor of electrical and computer engineering. “Overall, the findings imply that the robot has a positive effect on students.”
Dautenhahn has been working on robotics in the context of disability for many years and incorporates principles of equity, inclusion and diversity in research projects.
Students with learning disabilities may benefit from additional learning support, such as one-on-one instruction and the use of smartphones and tablets.
Educators have in recent years explored the use of social robots to help students learn, but most often, their research has focused on children with Autism Spectrum Disorder. As a result, little work has been done on the use of socially assistive robots for students with learning disabilities.

Along with two other Waterloo engineering researchers and three experts from the Learning Disabilities Society in Vancouver, Dautenhahn decided to change this, conducting a series of tests with a small humanoid robot called QT.
Dautenhahn, the Canada 150 Research Chair in Intelligent Robotics, said the robot’s ability to perform gestures using its head and hands, accompanied by its speech and facial features, makes it very suitable for use with children with learning disabilities.
Building on promising earlier research, the researchers divided 16 students with learning disabilities into two groups. In one group, students worked one-on-one with an instructor only. In the other group, the students worked one-on-one with an instructor and a QT robot. In the latter group, the instructor used a tablet to direct the robot, which then autonomously performed various activities using its speech and gestures.
While the instructor controlled the sessions, the robot took over at certain times, triggered by the instructor, to lead the student.
Besides introducing the session, the robot set goals and provided self-regulating strategies, if necessary. If the learning process was getting off-track, the robot used strategies such as games, riddles, jokes, breathing exercises and physical movements to redirect the student back to the task.
Students who worked with the robot, Dautenhahn said, “were generally more engaged with their tasks and could complete their tasks at a higher rate compared” to the students who weren’t assisted by a robot. Further studies using the robot are planned.
A paper on the study, User Evaluation of Social Robots as a Tool in One-to-one Instructional Settings for Students with Learning Disabilities, was recently presented at the International Conference on Social Robotics in Florence, Italy. More

For the first time, an international team of researchers, including those from the University of Tokyo’s Institute for Solid State Physics, has demonstrated a switch, analogous to a transistor, made from a single molecule called fullerene. By using a carefully tuned laser pulse, the researchers are able to use fullerene to switch the path of an incoming electron in a predictable way. This switching process can be three to six orders of magnitude faster than switches in microchips, depending on the laser pulses used. Fullerene switches in a network could produce a computer beyond what is possible with electronic transistors, and they could also lead to unprecedented levels of resolution in microscopic imaging devices.
Over 70 years ago, physicists discovered that molecules emit electrons in the presence of electric fields, and later on, certain wavelengths of light. The electron emissions created patterns that enticed curiosity but eluded explanation. But this has changed thanks to a new theoretical analysis, the ramification of which could not only lead to new high-tech applications, but also improve our ability to scrutinize the physical world itself. Project Researcher Hirofumi Yanagisawa and his team theorized how the emission of electrons from excited molecules of fullerene should behave when exposed to specific kinds of laser light, and when testing their predictions, found they were correct.
“What we’ve managed to do here is control the way a molecule directs the path of an incoming electron using a very short pulse of red laser light,” said Yanagisawa. “Depending on the pulse of light, the electron can either remain on its default course or be redirected in a predictable way. So, it’s a little like the switching points on a train track, or an electronic transistor, only much faster. We think we can achieve a switching speed 1 million times faster than a classical transistor. And this could translate to real world performance in computing. But equally important is that if we can tune the laser to coax the fullerene molecule to switch in multiple ways at the same time, it could be like having multiple microscopic transistors in a single molecule. That could increase the complexity of a system without increasing its physical size.”
The fullerene molecule underlying the switch is related to the perhaps slightly more famous carbon nanotube, though instead of a tube, fullerene is a sphere of carbon atoms. When placed on a metal point — essentially the end of a pin — the fullerenes orientate a certain way so they will direct electrons predictably. Fast laser pulses on the scale of femtoseconds, quadrillionths of a second, or even attoseconds, quintillionths of a second, are focused on the fullerene molecules to trigger the emission of electrons. This is the first time laser light has been used to control the emission of electrons from a molecule in this way.
“This technique is similar to the way a photoelectron emission microscope produces images,” said Yanagisawa. “However, those can achieve resolutions at best around 10 nanometers, or ten-billionths of a meter. Our fullerene switch enhances this and allows for resolutions of around 300 picometers, or three-hundred-trillionths of a meter.”
In principle, as multiple ultrafast electron switches can be combined into a single molecule, it would only take a small network of fullerene switches to perform computational tasks potentially much faster than conventional microchips. But there are several hurdles to overcome, such as how to miniaturize the laser component, which would be essential to create this new kind of integrated circuit. So, it may still be many years before we see a fullerene switch-based smartphone. More

The “metaverse” has captured the public imagination as a world of limitless possibilities that can influence all aspects of life. Discussions about the utility of completely immersible virtual environments were initially limited to a small number of tech and Sci-Fi circles until the rebranding of Facebook as “Meta” in 2021. The concept of the metaverse has gained a lot of attention since then, and researchers are now starting to explore ways in which virtual environments can be used to improve scientific and health research.
What are the key opportunities and uncertainties in the metaverse that can help us better manage non-communicable diseases? This is the subject of a paper recently published in the Journal of Medical Internet Research, authored by Associate Professor Javad Koohsari from the School of Knowledge Science at Japan Advanced Institute of Science and Technology (JAIST), who is also an adjunct researcher at the Faculty of Sport Sciences at Waseda University, along with Professor Yukari Nagai from JAIST; Professor Tomoki Nakaya from Tohoku University; Professor Akitomo Yasunaga from Bunka Gakuen University; Associate Professor Gavin R. McCormack from University of Calgary; Associate Professor Daniel Fuller from University of Saskatchewan; and Professor Koichiro Oka from Waseda University. The team lists three ways in which the metaverse might potentially be used for large-scale health interventions targeting non-communicable diseases.
Non-communicable diseases like diabetes, heart disease, strokes, chronic respiratory disease, cancers, and mental illness are greatly influenced by the “built environment,” i.e., the human-made surroundings we constantly interact with. Built environments can affect health directly through acute effects like pollution or indirectly, by influencing physical activity, sedentary behaviour, diet and sleep. Therefore, health interventions that modify built environments can be used to reduce the health burden of non-communicable diseases.
This is where the metaverse can be of assistance. Experiments conducted in virtual settings within the metaverse can be used to investigate the effectiveness of large-scale interventions before they are implemented, saving time and money. “Within a metaverse, study participants could be randomised to experience different built environment exposures such as high and low density, high and low walkability, or different levels of nature or urban environments,”explains Prof. Koohsari, the lead author of the paper, who is among the top 2% of most influential researchers worldwide across all scientific disciplines in 2021. He further adds, “This article will be of particular interest to experts in public health, urban design, epidemiology, medicine, and environmental sciences, especially those considering using the metaverse for research and intervention purposes.”
Secondly, the article notes that the metaverse itself can be used to implement health interventions. For instance, the metaverse can give people exposure to natural “green” environments even when they have little or no access to these environments in the real world. In this way, the metaverse may reduce the negative mental health effects associated with crowded, stress-inducing environments.
Virtual living spaces and offices within the metaverse can be endlessly customised. Moreover, changes to environments within the metaverse can be implemented with the click of a button. Hence, thirdly, the metaverse may also offer a virtual space to test new office and built environment designs in real-time. Prof. Koohsari adds, “A metaverse could allow stakeholders to experience, build, and collaboratively modify the proposed changes to the built environment before these interventions are implemented in the physical world.”
Although it lists several ways in which the metaverse can transform public health interventions by modifying built environments, the article notes key limitations of the metaverse in simulating the real world. In particular, the current state of the metaverse does now allow for the testing of many human behaviours or their interaction with built environments. In addition, the population of the metaverse may not be representative, as people from economically lower strata have limited access to virtual reality technology.
The article also explores ways in which the metaverse can negatively affect population health. For example, excessive immersion in virtual environments may lead to social isolation, anti-social behaviours, and negative health effects associated with physical inactivity or increased screen time. Finally, the article notes that excess reliance on artificial intelligence may lead to the replication of real-world biases and social inequalities in the virtual world. In conclusion, Prof. Koohsari remarks, “It is best, sooner rather than later, to face the prospects and challenges that the metaverse can offer to different scientific fields, and in our case, to public health.” More

Infants outperform artificial intelligence in detecting what motivates other people’s actions, finds a new study by a team of psychology and data science researchers. Its results, which highlight fundamental differences between cognition and computation, point to shortcomings in today’s technologies and where improvements are needed for AI to more fully replicate human behavior.
“Adults and even infants can easily make reliable inferences about what drives other people’s actions,” explains Moira Dillon, an assistant professor in New York University’s Department of Psychology and the senior author of the paper, which appears in the journal Cognition. “Current AI finds these inferences challenging to make.”
“The novel idea of putting infants and AI head-to-head on the same tasks is allowing researchers to better describe infants’ intuitive knowledge about other people and suggest ways of integrating that knowledge into AI,” she adds.
“If AI aims to build flexible, commonsense thinkers like human adults become, then machines should draw upon the same core abilities infants possess in detecting goals and preferences,” says Brenden Lake, an assistant professor in NYU’s Center for Data Science and Department of Psychology and one of the paper’s authors.
It’s been well-established that infants are fascinated by other people — as evidenced by how long they look at others to observe their actions and to engage with them socially. In addition, previous studies focused on infants’ “commonsense psychology” — their understanding of the intentions, goals, preferences, and rationality underlying others’ actions — have indicated that infants are able to attribute goals to others and expect others to pursue goals rationally and efficiently. The ability to make these predictions is foundational to human social intelligence.
Conversely, “commonsense AI” — driven by machine-learning algorithms — predicts actions directly. This is why, for example, an ad touting San Francisco as a travel destination pops up on your computer screen after you read a news story on a newly elected city official. However, what AI lacks is flexibility in recognizing different contexts and situations that guide human behavior.
To develop a foundational understanding of the differences between humans’ and AI’s abilities, the researchers conducted a series of experiments with 11-month-old infants and compared their responses to those yielded by state-of-the-art learning-driven neural-network models.
To do so, they deployed the previously established “Baby Intuitions Benchmark” (BIB) — six tasks probing commonsense psychology. BIB was designed to allow for testing both infant and machine intelligence, allowing for a comparison of performance between infants and machines and, significantly, providing an empirical foundation for building human-like AI.
Specifically, infants on Zoom watched a series of videos of simple animated shapes moving around the screen — similar to a video game. The shapes’ actions simulated human behavior and decision-making through the retrieval of objects on the screen and other movements. Similarly, the researchers built and trained learning-driven neural-network models — AI tools that help computers recognize patterns and simulate human intelligence — and tested the models’ responses to the exact same videos.
Their results showed that infants recognize human-like motivations even in the simplified actions of animated shapes. Infants predict that these actions are driven by hidden but consistent goals — for example, the on-screen retrieval of the same object no matter what location it’s in and the movement of that shape efficiently even when the surrounding environment changes. Infants demonstrate such predictions through their longer looking to such events that violate their predictions — a common and decades-old measurement for gauging the nature of infants’ knowledge. Adopting this “surprise paradigm” to study machine intelligence allows for direct comparisons between an algorithm’s quantitative measure of surprise and a well-established human psychological measure of surprise — infants’ looking time. The models showed no such evidence of understanding the motivations underlying such actions, revealing that they are missing key foundational principles of commonsense psychology that infants possess.
“A human infant’s foundational knowledge is limited, abstract, and reflects our evolutionary inheritance, yet it can accommodate any context or culture in which that infant might live and learn,” observes Dillon.
The research was supported by grants from the National Science Foundation (DRL1845924) and the Defense Advanced Projects Research Agency (HR001119S0005). More

An effective, stable solid-state electrochemical transistor has been developed, heralding a new era in thermal management technology.
In modern electronics, a large amount of heat is produced as waste during usage — this is why devices such as laptops and mobile phones become warm during use, and require cooling solutions. In the last decade, the concept of managing this heat using electricity has been tested, leading to the development of electrochemical thermal transistors — devices that can be used to control heat flow with electrical signals. Currently, liquid-state thermal transistors are in use, but have critical limitations: chiefly, any leakage causes the device to stop working.
A research team at Hokkaido University lead by Professor Hiromichi Ohta at the Research Institute for Electronic science has developed the first solid-state electrochemical thermal transistor. Their invention, described in the journal Advanced Functional Materials, is much more stable than and just as effective as current liquid-state thermal transistors.
“A thermal transistor consists broadly of two materials, the active material and the switching material,” explains Ohta. “The active material has changeable thermal conductivity, and the switching material is used to control the thermal conductivity of the active material.”
The team constructed their thermal transistor on a yttrium oxide-stabilized zirconium oxide base, which also functioned as the switching material, and used strontium cobalt oxide as the active material. Platinum electrodes were used to supply the power required to control the transistor.
The thermal conductivity of the active material in the “on” state was comparable to some liquid-state thermal transistors. In general, thermal conductivity of the active material was four times higher in the “on” state compared to the “off” state. Further, the transistor was stable over 10 use cycles, better than some current liquid-state thermal transistors. This behavior was tested across more than 20 separately fabricated thermal transistors, ensuring the results were reproducible. The only drawback was the operating temperature of around 300°C.
“Our findings show that solid-state electrochemical thermal transistors have the potential to be just as effective as liquid-state electrochemical thermal transistors, with none of their limitations,” concludes Ohta. “The main hurdle to developing practical thermal transistors is the high resistance of the switching material, and hence a high operating temperature. This will be the focus of our future research.” More