Computers Math

University of Queensland scientists have cracked a problem that’s frustrated chemists and physicists for years, potentially leading to a new age of powerful, efficient, and environmentally friendly technologies.
Using quantum mechanics, Professor Ben Powell from UQ’s School of Mathematics and Physics has discovered a ‘recipe’ which allows molecular switches to work at room temperature.
“Switches are materials that can shift between two or more states, such as on and off or 0 and 1, and are the basis of all digital technologies,” Professor Powell said.
“This discovery paves the way for smaller and more powerful and energy efficient technologies.
“You can expect batteries will last longer and computers to run faster.”
Until now, molecular switching has only been possible when the molecules are extremely cold — at temperatures below minus 250 degrees centigrade. More

As far as data security is concerned, there is an even greater danger than remote cyberattacks: namely tampering with hardware that can be used to read out information — such as credit card data from a card reader. Researchers in Bochum have developed a new method to detect such manipulations. They monitor the systems with radio waves that react to the slightest changes in the ambient conditions. Unlike conventional methods, they can thus protect entire systems, not just individual components — and they can do it at a lower cost. The RUB’s science magazine Rubin features a report by the team from Ruhr-Universität Bochum (RUB), the Max Planck Institute for Security and Privacy and the IT company PHYSEC.
Paul Staat and Johannes Tobisch presented their findings at the IEEE Symposium on Security and Privacy, which took place in the USA from 23 to 25 May 2022. Both researchers are doing their PhDs at RUB and conducting research at the Max Planck Institute for Security and Privacy in Bochum in Professor Christof Paar’s team. For their research, they are cooperating with Dr. Christian Zenger from the RUB spin-off company PHYSEC.
Protection through radio waves
Data is ultimately nothing more than electrical currents that travel between different computer components via conductive paths. A tiny metallic object, located in the right place on the hardware, can be enough to tap into the information streams. To date, only individual components of systems, such as a crucial memory element or a processor, can be protected from such manipulations. “Typically, this is done with a type of foil with thin wires in which the hardware component is wrapped,” explains Paul Staat. “If the foil is damaged, an alarm is triggered.”
The radio wave technology from Bochum, however, can be used to monitor an entire system. To this end, the researchers install two antennas in the system: a transmitter and a receiver. The transmitter sends out a special radio signal that spreads everywhere in the system and is reflected by the walls and computer components. All these reflections cause a signal to reach the receiver that is as characteristic of the system as a fingerprint.
Technology reacts to the slightest changes
Tiny changes to the system are enough to have a noticeable effect on the fingerprint, as the team demonstrated in experiments. The IT experts equipped a conventional computer with radio antennas and punctured its housing with holes at regular intervals. Through these holes, the researchers let a fine metal needle penetrate the inside of the system and checked whether they notice the change in the radio signal. In the process, they varied the thickness of the needle, the position and the depth of penetration.
With the computer running, they reliably detected the penetration of a needle 0.3 millimetres thick with their system from a penetration depth of one centimetre. The system still detected a needle that was only 0.1 millimetres thick — about as thick as a hair — but not in all positions. “The closer the needle is to the receiving antenna, the easier it is to detect, explains Staat. “Therefore, in practical applications, it makes sense to think carefully about where you place the antennas,” adds Tobisch. “They should be as close as possible to the components that require a high degree of protection.”
Basically, the technology is suitable for both high-security applications and everyday problem. The IT company PHYSEC already uses it to prevent unauthorised manipulation of critical infrastructure components.
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Materials provided by Ruhr-University Bochum. Original written by Julia Weiler. Note: Content may be edited for style and length. More

Researchers have pioneered a technique that can dramatically accelerate certain types of computer programs automatically, while ensuring program results remain accurate.
Their system boosts the speeds of programs that run in the Unix shell, a ubiquitous programming environment created 50 years ago that is still widely used today. Their method parallelizes these programs, which means that it splits program components into pieces that can be run simultaneously on multiple computer processors.
This enables programs to execute tasks like web indexing, natural language processing, or analyzing data in a fraction of their original runtime.
“There are so many people who use these types of programs, like data scientists, biologists, engineers, and economists. Now they can automatically accelerate their programs without fear that they will get incorrect results,” says Nikos Vasilakis, research scientist in the Computer Science and Artificial Intelligence Laboratory (CSAIL) at MIT.
The system also makes it easy for the programmers who develop tools that data scientists, biologists, engineers, and others use. They don’t need to make any special adjustments to their program commands to enable this automatic, error-free parallelization, adds Vasilakis, who chairs a committee of researchers from around the world who have been working on this system for nearly two years.
Vasilakis is senior author of the group’s latest research paper, which includes MIT co-author and CSAIL graduate student Tammam Mustafa and will be presented at the USENIX Symposium on Operating Systems Design and Implementation.Co-authors include lead author Konstantinos Kallas, a graduate student at the University of Pennsylvania; Jan Bielak, a student at Warsaw Staszic High School; Dimitris Karnikis, a software engineer at Aarno Labs; Thurston H.Y. Dang, a former MIT postdoc who is now a software engineer at Google; and Michael Greenberg, assistant professor of computer science at the Stevens Institute of Technology. More

A team of engineers at the University of California San Diego has demonstrated for the first time that the Bluetooth signals emitted constantly by our mobile phones have a unique fingerprint that can be used to track individuals’ movements.
Mobile devices, including phones, smartwatches and fitness trackers, constantly transmit signals, known as Bluetooth beacons, at the rate of roughly 500 beacons per minute.These beacons enable features like Apple’s “Find My” lost device tracking service; COVID-19 tracing apps; and connect smartphones to other devices such as wireless earphones.
Prior research has shown that wireless fingerprinting exists in WiFi and other wireless technologies. The critical insight of the UC San Diego team was that this form of tracking can also be done with Bluetooth, in a highly accurate way.
“This is important because in today’s world Bluetooth poses a more significant threat as it is a frequent and constant wireless signal emitted from all our personal mobile devices,” said Nishant Bhaskar, a Ph.D. student in the UC San Diego Department of Computer Science and Engineering and one of the paper’s lead authors.
The team, which includes researchers from the Departments of Computer Science and Engineering and Electrical and Computer Engineering, presented its findings at the IEEE Security & Privacy conference in Oakland, Calif., on May 24, 2022.
All wireless devices have small manufacturing imperfections in the hardware that are unique to each device. These fingerprints are an accidental byproduct of the manufacturing process. These imperfections in Bluetooth hardware result in unique distortions, which can be used as a fingerprint to track a specific device. For Bluetooth, this would allow an attacker to circumvent anti-tracking techniques such as constantly changing the address a mobile device uses to connect to Internet networks. More

As electronic, thermoelectric and computer technologies have been miniaturized to nanometer scale, engineers have faced a challenge studying fundamental properties of the materials involved; in many cases, targets are too small to be observed with optical instruments.
Using cutting-edge electron microscopes and novel techniques, a team of researchers at the University of California, Irvine, the Massachusetts Institute of Technology and other institutions has found a way to map phonons — vibrations in crystal lattices — in atomic resolution, enabling deeper understanding of the way heat travels through quantum dots, engineered nanostructures in electronic components.
To investigate how phonons are scattered by flaws and interfaces in crystals, the researchers probed the dynamic behavior of phonons near a single quantum dot of silicon-germanium using vibrational electron energy loss spectroscopy in a transmission electron microscope, equipment housed in the Irvine Materials Research Institute on the UCI campus. The results of the project are the subject of a paper published today in Nature.
“We developed a novel technique to differentially map phonon momenta with atomic resolution, which enables us to observe nonequilibrium phonons that only exist near the interface,” said co-author Xiaoqing Pan, UCI professor of materials science and engineering and physics, Henry Samueli Endowed Chair in Engineering, and IMRI director. “This work marks a major advance in the field because it’s the first time we have been able to provide direct evidence that the interplay between diffusive and specular reflection largely depends on the detailed atomistic structure.”
According to Pan, at the atomic scale, heat is transported in solid materials as a wave of atoms displaced from their equilibrium position as heat moves away from the thermal source. In crystals, which possess an ordered atomic structure, these waves are called phonons: wave packets of atomic displacements that carry thermal energy equal to their frequency of vibration.
Using an alloy of silicon and germanium, the team was able to study how phonons behave in the disordered environment of the quantum dot, in the interface between the quantum dot and the surrounding silicon, and around the dome-shaped surface of the quantum dot nanostructure itself. More

What’s the relationship between people’s perception of beauty and animals’ conservation needs? According to a machine-learning study by Nicolas Mouquet at the University of Montpellier, France, and colleagues, publishing June 7thin the open-access journal PLOS Biology, the reef fishes that people find most beautiful tend to be the lowest priority for conservation support.
The researchers asked 13,000 members of the public to rate the aesthetic attractiveness of 481 photographs of ray-finned reef fishes in an online survey and used this data to train a convolutional neural network. They then used the trained neural network to generate predictions for additional 4,400 photographs featuring 2,417 of the most encountered reef fish species.
Combining the public’s ratings with the neural network’s predictions, they found that bright, colorful fish species with rounder bodies tended to be rated as the most beautiful. However, the species that were ranked as more attractive tended to be less distinctive in terms of their ecological traits and evolutionary history. Furthermore, species listed on the IUCN Red List as “Threatened” or whose conservation status has not yet been evaluated had lower aesthetic value on average than species categorized as “Least Concern.” Unattractive species were also of greater commercial interest, whereas aesthetic value was not correlated with a species’ importance for subsistence fisheries.
Our innate preferences for shape and color are probably a consequence of the way the human brain processes colors and patterns, the authors say, but mismatches between aesthetic value, ecological function, and extinction vulnerability may mean that the species most in need of public support are the least likely to receive it. The ecological and evolutionary distinctiveness of unattractive fishes makes them important for the functioning of the whole reef, and their loss could have a disproportionate impact on these high-biodiversity ecosystems.
Mouquet adds, “Our study provides, for the first time, the aesthetic value of 2,417 reef fish species. We found that less beautiful fishes are the most ecologically and evolutionary distinct species and those recognized as threatened. Our study highlights likely important mismatches between potential public support for conservation and the species most in need of this support.”
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Materials provided by PLOS. Note: Content may be edited for style and length. More

Electro-optic modulators, which control aspects of light in response to electrical signals, are essential for everything from sensing to metrology and telecommunications. Today, most research into these modulators is focused on applications that take place on chips or within fiber optic systems. But what about optical applications outside the wire and off the chip, like distance sensing in vehicles?
Current technologies to modulate light in free space are bulky, slow, static, or inefficient. Now, researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS), in collaboration with researchers at the department of Chemistry at the University of Washington, have developed a compact and tunable electro-optic modulator for free space applications that can modulate light at gigahertz speed.
“Our work is the first step toward a class of free-space electro-optic modulators that provide compact and efficient intensity modulation at gigahertz speed of free-space beams at telecom wavelengths,” said Federico Capasso, Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering, senior author of the paper.
The research is published in Nature Communications.
Flat, compact metasurfaces are ideal platforms for controlling light in free space but most are static, meaning they can’t switch on and off — a key functionality for modulators. Some active metasurfaces can effectively modulate light, but only at low speeds, just a few megahertz.
For applications such as sensing or free-space communications, you need short, fast bursts of light, on the scale of gigahertz.
The high-speed modulator developed by Capasso and his team brings together metasurface resonators with high-performance organic electro-optical materials and high-frequency electronic design to efficiently modulate the intensity of light in free space.
The modulator consists of a thin layer of an organic electro-optic material deposited on top of a metasurface etched with sub-wavelength resonators integrated with microwave electronics. When a microwave field is applied to the electro-optical material, its refractive index changes, changing the intensity of light that is being transmitted by the metasurface in mere nanoseconds.
“With this design, we now can modulate light 100 to 1,000 times faster than previously,” said Ileana-Cristina Benea-Chelmus, a research associate in the Capasso Lab and first author of the paper. “This speed advance opens new possibilities in computing or communications and the tunability of the metasurface opens up a vast application space for custom-tailored, ultracompact photonics that may in the future be deposited onto any nanoscale free-space optical product.”
Next, the researchers aim to see if they can modulate light even faster and, by changing the design of the metasurface, modulate other aspects of light such as phase or polarization.
The Harvard Office of Technology Development has protected the intellectual property associated with this project.
The research was co-authored by Sydney Mason, Maryna L. Meretska, Dmitry Kazakov, Amirhassan Shams-Ansari from SEAS, and Larry R. Dalton and Delwin Elder of the University of Washington. It was supported in part by the Air Force Office of Scientific Research under award numbers FA9550-19-1-0352 and FA9550-19-1-0069 and the Office of Naval Research (ONR) MURI program, under grant number N00014-20-1-2450. This work was performed in part at the Harvard University Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Coordinated Infrastructure Network (NNCI), which is supported by the National Science Foundation under NSF award no. ECCS-2025158. More

A new theory of economic decision-making from Mina Mahmoudi, a lecturer in the Department of Economics at Rensselaer Polytechnic Institute, offers an explanation as to why humans, in general, make decisions that are simply adequate, not optimal.
In research published today in the Review of Behavioral Economics, Dr. Mahmoudi theorizes an aspect of relative thinking explaining people may use ratios in their decision-making when they should only use absolute differences. The inverse is also possible.
To explain this behavioral anomaly, Dr. Mahmoudi has developed a ratio-difference theory that gives weight to both ratio and difference comparisons. This theory seeks to more accurately capture the manner by which a boundedly rational decision-maker might operationally distinguish whether one alternative is better than another.
“Effectively solving some economic problems requires one to think in terms of differences while others require one to think in terms of ratios,” Dr. Mahmoudi said. “Because both types of thinking are necessary, it is reasonable to think people develop and apply both types. However, it is also reasonable to expect that people misapply the two types of thinking, especially when less experienced with the context.”
Past studies have shown that when given the opportunity to save, for example, $5 on a $25 item or a $500 item, people in general would put in more effort to save the money on the lower-cost product than the more expensive item. They believe they are getting a better deal because the ratio of cost to savings is higher. In fact, the $5 saved is the same for both items and the perfect, or optimal choice, would be to look at the absolute savings and work equally hard to save each $5. People should use differences to solve this problem, but many seem to make unreasonable decisions because they apply ratio thinking.
“Understanding how the cognitive and motivational characteristics of human beings and the operating procedures of organizations influence the working of economic systems is of critical importance,” Dr. Mahmoudi said. “Many economic behaviors such as imitation occur and many economic institutions like inventories exist because people cannot maximize or because markets are not in equilibrium. Our model provides an example of a behavior that occurs because people cannot maximize.”
This model can be applied to a variety of behavioral economic experiments in the gambling industry and financial markets among others.
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Materials provided by Rensselaer Polytechnic Institute. Original written by Jeanne Hedden Gallagher. Note: Content may be edited for style and length. More