In environments where it is vital for customers to be aware of service information, such as in restaurants, amusement parks or for transportation routes, accurate congestion information can provide real-time data about aspects like service availability and queue length.

Yet because congestion information can quickly become outdated, interruptions in queuing systems often cause users to seek other options. While such choices may serve them better individually, this behavior can make the entire system inefficient, said Ness Shroff, senior author of the study and a professor of computer science and engineering at The Ohio State University.

“If information is outdated and thus everybody’s joining what appears to be the shortest path, you’re going to create congestion over that path,” said Shroff. This bottleneck can lead to gaps in fresh information for future customers to access and use, and impede overall service progress over time.

To better regulate this information learning, researchers have developed a way to incentivize people to choose less popular service alternatives. The proposed method is a side-payment mechanism that would periodically charge customers who contribute to overcrowding by making “selfish” choices and reward others for exploring alternative avenues.

In experiments using real-world datasets, the team found that this system was adept at balancing congestion with addressing user needs via alternative routes, resulting in steady performance. According to Shroff, adding incentivized settings to mobile queuing platforms goes a long way to making these complex systems work more sensibly for everyone.

“We calculate when the public value of fresh information is worth the congestion it takes to get it, and then build incentives that steer individual choices towards that balance,” he said. “Giving incentives for people to try out different routes might in fact create better opportunities for all.”

The study was published in the journal IEEE/ACM Transactions on Networking.

According to the study, this team’s work is the first to examine how human choice can impact system outcomes. Hongbo Li, lead author of the study and a postdoctoral scholar at the AI-EDGE Institute at Ohio State, calls this phenomenon human-in-loop learning (HILL), noting that leveraging it can provide researchers with new insights into the growing class of service systems that rely on decentralized, customer-driven data.

“Designing a mechanism to change a user’s decision to be both consistent with social welfare and long-term utility can be difficult,” he said. “It has to be done in a way that doesn’t directly hurt their service benefit.”

A promising use-case scenario could look like this: A user visiting a car-charging station might be rewarded for choosing a less crowded location farther away, but penalized for visiting a closer station that is already at risk of becoming overloaded. Although both visits generate useful information for the operating system, the former is more valuable because curbing congestion helps reduce system inefficiencies, said Li.

“In testing, we saw that even average use saves costs and energy,” he said. “This means our approach is amazingly good for the social optimum.”

Besides keeping these systems more accurate, this team’s mechanism would also limit expenses by using the money earned from those penalized to pay out rewards. With millions of people relying on queuing systems to navigate their day-to-day lives, these meaningful findings could inform future network design for a wide number of technologies and industries, the researchers say.

To advance the work, the team next aims to test how well their system works when people make different, unexpected choices regarding prices, risks and personal convenience.

“Our next step may be to develop mechanisms that are more robust to heterogeneous users and to test them experimentally in different scenarios,” said Li. “It’s important to consider human behavior in engineering, and our goal was to show that.”

Other co-authors include Lingjie Duan from the Singapore University of Technology and Design.

Superconductivity, or the ability of certain materials to conduct electric currents without any energy loss when cooled below a critical temperature, is a property still not very well understood. While a major challenge, understanding more about its formation mechanisms could lead to better, more long-lasting materials as well as more powerful quantum devices. 

Led by Chun Ning (Jeanie) Lau, senior author of the study and a professor of physics at The Ohio State University, the research team constructed a special material called twisted bilayer graphene — a layer of carbon stacked onto another and rotated at a small angle. 

By attaching the material to a man-made synthetic diamond called strontium titanate, Lau and colleagues were able to see and control how strongly electrons — tiny subatomic particles — in the system interacted with each other. Electron interactions that control properties like magnetic states and chemical bonding come in pairs, and by adjusting the “settings” of these pairs, the team was able to switch the material’s superconductivity on and off. 

“Electrons normally repel each other, but in superconductors they form pairs; this pair formation is the key to a superconductor’s ability to conduct electricity without dissipation,” said Lau. “Our evidence suggests that electrons themselves, depending on their sensitivity to their nearby environment, are unexpectedly important for material changes.”

The researchers were surprised to find that when they increased their adjustments, superconductivity had decreased. This result is different from conventional superconductors, where, if repelling forces between electrons are suppressed, the pairing gets stronger, highlighting the unusual nature of new materials like twisted bilayer graphene to successfully direct electricity. 

“If you could transmit electricity without energy loss, that would be hugely important for technologies used in our everyday life,” said Lau. “Despite the fundamental questions that still need answers, this work basically provides a path toward a new type of physics mechanism.”

Such a discovery could help scientists develop materials that superconduct at higher temperatures – even room temperature, a “holy grail” in the field that, if achieved, could transform their current understanding of electronics, power transmission, and communications.

The study was published April 7 in the journal Nature Physics.

Overall, these results reveal a simpler way to control the conditions needed to create and control the atomic power behind superconductivity. For instance, because many high-temperature superconductors have limitations that cap their productivity, using the environment to drive their abilities could boost their power as well as allow scientists to build more efficient electronics. 

These potential applications are not far off, according to Xueshi Gao, lead author of the study and a current PhD student in physics at Ohio State: He believes his team’s findings will soon be useful to many different types of systems and experiments across the field. 

“The mechanism of superconductivity in the twisted bilayer graphene system we used is still not well understood,” said Gao. “But our result can shed light on and help people to better understand the concept when applying it to future work.”

Still, the team emphasizes that the model is only an initial step toward understanding unexplored electronic interactions, and next steps will involve testing other types of interactions and investigating the various complex physics questions that their work opens up. 

“We’re showing capabilities that we haven’t shown before, so many people in the field are getting really excited about this result,” said Lau. 

Other Ohio State co-authors include Aatmaj Rajesh, Emilio Codecido, Daria Sharifi, Zheneng Zhang, Youwei Liu and Marc Bockrath, as well as Alejandro Jimeno-Pozo, Pierre Pantaleon and Paco Guinea from Imdea Nanoscience in Spain, and Kenji Watanabe and Takashi Taniguchi from the National Institute for Materials Science in Japan. This work was supported by the Department of Energy and the National Science Foundation. 

From transportation and telecommunications to finance and public infrastructure, nearly all sectors depend on Global Navigation Satellite Systems (GNSS) such as GPS for critical positioning, navigation and timing information. Yet as these signals are highly susceptible to interference like intentional jamming and spoofing, new technologies are needed to counter this dependence. 

Now, by exploiting signals from the Starlink and OneWeb constellations — satellites primarily used to deliver secure internet connectivity — researchers found they could be used to improve ship navigation accuracy in the Arctic, an area where GPS coverage and signals are typically degraded. Results showed that exploiting Starlink and OneWeb LEO signals with height data from a ship sailing off the west coast of Greenland significantly increased navigation accuracy, effectively reducing errors from more than a kilometer (without GPS) to 27 meters.

Being able to yield more precise navigation data in such a challenging region like the Arctic means that safe and effective satellite “eavesdropping” may be feasible from nearly anywhere on Earth, said Zak Kassas, co-author of the study and TRC Endowed Chair in Intelligent Transportation Systems and professor of electrical and computer engineering at The Ohio State University. 

“When you lose GPS on a plane or a ship there is no solution at the time being,” said Kassas, who is also director of Ohio State’s Department of Transportation Center for Automated Vehicles Research with Multimodal AssurEd Navigation (CARMEN). “What we showed is that there are solutions ready to be deployed in the field with existing systems.”

The study was recently presented at the 43rd IEEE Military Communications Conference in Los Angeles. It won the IEEE Frederick W. Ellersick Award for the Best Paper in the Unclassified Technical Program. 

This work builds off previous work from Kassas’ ASPIN lab that was the first to exploit Starlink for positioning. Efforts to scale up that research led the team to seek ways to improve their system using ground receivers that can passively listen to frequencies emitted from multiple LEO satellite constellations. Since then, Kassas’ team has demonstrated navigation with LEO satellites across the U.S., from St. Louis on a stationary receiver, to Pittsburgh on a ground vehicle, to Albuquerque on an extremely high-altitude balloon, to Columbus on a ground vehicle and a drone. In their latest experiment, they decided to leave the heartland.

In this experiment, they decided to test their work in the Arctic, as OneWeb’s 600 satellites are plentiful near the north and south poles, while Starlink’s more than 7,000 satellites are present across all other latitudes. 

“We can be smart about what we have already in the environment and use it to navigate,” said Kassas. “Ambient signals, whether they are terrestrial or non-terrestrial (such as LEO), are extremely useful for navigation if you know how to use them.”

According to Kassas, the researchers did not need assistance from the satellite operators (SpaceX and Eutelsat) to use the signals, and they emphasized that they had no access to the actual data being sent through the satellites – only to publicly available information related to the satellites’ downlink transmission frequency and a rough estimate of the satellites’ location.

This discovery, that even satellites that were not intended for navigation can be repurposed and tailored for location services, means that substantially advancing next-gen GNSS systems may be closer and more affordable than researchers thought. According to the study, these results have vital implications for aerospace and defense, and more importantly, because signals from LEO satellites are thousands of times more powerful than GNSS, they would be more secure and much harder to interrupt by bad actors. 

“If someone wants to interfere with LEO signals, they would have to put more effort into it,” said Kassas. The study also suggests that better navigation signal security might lower the risk of international incidents, as many officials suspect escalating cyberattacks caused both the Strait of Hormuz ship collision and the downing of the Azerbaijan Airlines Flight 8243. 

“Those cyberattacks on GPS are becoming the bread and butter of electronic warfare, and it’s spilling over to civilian systems,” said Kassas. Unsurprisingly, these issues mean that scientists and policymakers can’t afford to wait years to engineer new GNSS workarounds. Instead, the team feels that implementing the systems they’ve presented may be where optimization lies. 

“Our approach is economical, alleviating the need to build and operate new dedicated navigation systems, and sustainable, preserving the scarce spectrum and our space environment, so we believe it will be integrated into future navigation systems,” said Kassas. “We are showing that this dream can be a reality.”

Other co-authors include Will Barrett and Sharbel Kozhaya from Ohio State and David Marsh from The Wilson Center. 

Mushrooms have long been recognized for their extreme resilience and unique properties. Their innate abilities make them perfect specimens for bioelectronics, an emerging field that, for next-gen computing, could help develop exciting new materials. 

As one example, researchers from The Ohio State University recently discovered that common edible fungi, such as shiitake mushrooms, can be grown and trained to act as organic memristors, a type of data processor that can remember past electrical states. 

Their findings showed that these shiitake-based devices not only demonstrated similar reproducible memory effects to semiconductor-based chips but could also be used to create other types of low-cost, environmentally friendly, brain-inspired computing components.

“Being able to develop microchips that mimic actual neural activity means you don't need a lot of power for standby or when the machine isn't being used,” said John LaRocco, lead author of the study and a research scientist in psychiatry at Ohio State’s College of Medicine. “That's something that can be a huge potential computational and economic advantage.”

Fungal electronics aren’t a new concept, but they have become ideal candidates for developing sustainable computing systems, said LaRocco. This is because they minimize electrical waste by being biodegradable and cheaper to fabricate than conventional memristors and semiconductors, which often require costly rare-earth minerals and high amounts of energy from data centers. 

“Mycelium as a computing substrate has been explored before in less intuitive setups, but our work tries to push one of these memristive systems to its limits,” he said. 

The study was recently published in the journal PLOS ONE.

To explore the new memristors' capabilities, researchers cultured samples of shiitake and button mushrooms. Once mature, they were dehydrated to ensure long-term viability, connected to special electronic circuits, and then electrocuted at various voltages and frequencies. 

“We would connect electrical wires and probes at different points on the mushrooms because distinct parts of it have different electrical properties,” said LaRocco. “Depending on the voltage and connectivity, we were seeing different performances.”

After two months, the team discovered that when used as RAM – the computer memory that stores data – their mushroom memristor was able to switch between electrical states at up to 5,850 signals per second, with about 90% accuracy. However, performance dropped as the frequency of the electrical voltages increased, but much like an actual brain, it could be fixed by connecting more mushrooms to the circuit.  

Overall, their research details how surprisingly easy it is to program and preserve mushrooms to behave in unexpected and useful ways, said Qudsia Tahmina, co-author of the study and an associate professor in electrical and computer engineering at Ohio State. Moreover, it’s an example of how technology can advance when it relies on the natural world.

“Society has become increasingly aware of the need to protect our environment and ensure that we preserve it for future generations,” said Tahmina. “So that could be one of the driving factors behind new bio-friendly ideas like these.”

Building on the flexibility mushrooms offer also suggests there are possibilities for scaling up fungal computing, said Tahmina. For instance, larger mushroom systems may be useful in edge computing and aerospace exploration; smaller ones in enhancing the performance of autonomous systems and wearable devices. 

Organic memristors are still in early development, but future work could optimize the production process by improving cultivation techniques and miniaturizing the devices, as viable fungal memristors would need to be far smaller than what researchers achieved in this work. 

“Everything you'd need to start exploring fungi and computing could be as small as a compost heap and some homemade electronics, or as big as a culturing factory with pre-made templates,” said LaRocco. “All of them are viable with the resources we have in front of us now.” 

Other Ohio State co-authors include Ruben Petreaca, John Simonis and Justin Hill. This study was supported by the Honda Research Institute.