Computers Math

A component of computer processors that connects different parts of the chip can be exploited by malicious agents who seek to steal secret information from programs running on the computer, MIT researchers have found.
Modern computer processors contain many computing units, called cores, which share the same hardware resources. The on-chip interconnect is the component that enables these cores to communicate with each other. But when programs on multiple cores run simultaneously, there is a chance they can delay one another when they use the interconnect to send data across the chip at the same time.
By monitoring and measuring these delays, a malicious agent could conduct what is known as a “side-channel attack” and reconstruct secret information that is stored in a program, such as a cryptographic key or password.
MIT researchers reverse-engineered the on-chip interconnect to study how this kind of attack would be possible. Drawing on their discoveries, they built an analytical model of how traffic flows between the cores on a processor, which they used to design and launch surprisingly effective side-channel attacks. Then they developed two mitigation strategies that enable a user to improve security without making any physical changes to the computer chip.
“A lot of current side-channel defenses are ad hoc — we see a little bit of leakage here and we patch it. We hope our approach with this analytical model pushes more systematic and robust defenses that eliminate whole classes of attacks at the same time,” says co-lead author Miles Dai, MEng ’21.
Dai wrote the paper with co-lead author Riccardo Paccagnella, a graduate student at the University of Illinois at Urbana-Champaign; Miguel Gomez-Garcia ’22; John McCalpin, a research scientist at Texas Advanced Computing Center; and senior author Mengjia Yan, the Homer A. Burnell Career Development Assistant Professor of Electrical Engineering and Computer Science (EECS) and a member of the Computer Science and Artificial Intelligence Laboratory (CSAIL). The research is being presented at the USENIX Security Conference. More

Researchers have created a mathematical model to predict genetic resistance to antimalarial drugs in Africa to manage one of the biggest threats to global malarial control.
Malaria is a life-threatening disease caused by parasites and spread to humans through infected mosquitos. It is preventable and curable, yet resistance to current antimalarial drugs is causing avoidable loss of life. The World Health Organisation estimated there were 241 million cases of malaria worldwide in 2020, with more than 600,000 deaths.
In research published today in PLOS Computational Biology, an international research team used data from the WorldWide Antimalarial Resistance Network (WWARN), a global, scientifically independent collaboration, to map the prevalence of genetic markers that indicate resistance to Plasmodium falciparum — the parasite that causes malaria.
Lead author Associate Professor Jennifer Flegg from the University of Melbourne said malaria has devastating impacts on lower-income countries and effective treatment is key to elimination.
“The antimalarial drug sulfadoxine-pyrimethamine (SP) is commonly used in various preventative malaria treatment programs in Africa, particularly for infants, young children and during pregnancy. But we know its efficacy as a treatment is threatened in areas where resistance to SP is high,” Associate Professor Flegg said.
“The statistical mapping tool we have developed is critical for health organisations to understand the spread of antimalarial resistance. The model takes in the data that is available and fills in the gaps by making continuous predictions in space and time. More

They say timing is everything, and that couldn’t be more true for cell cycle progression and differentiation. Now, researchers from Japan have found that the circadian clock is crucial for proper plant development.
In a study published in Cell Reports, researchers at Nara Institute of Science and Technology (NAIST) have revealed that the circadian clock plays a guiding role in plant cell differentiation.
The circadian clock is involved in both cell-cycle progression and cell fate transitions. The involvement of circadian clocks in the process of differentiation has been shown in many multicellular organisms; however, how plant circadian clocks regulate cell differentiation remains unclear.
“Elucidating how the circadian clock is involved in cell differentiation is important to understand the basis of cell fate determination,” explains Motomu Endo, senior author of the study. “However, this has been difficult to investigate in plants because it is challenging to isolate single plants’ cells, and existing analytical methods rely on “pseudo-time” analysis that does not accurately reflect normal circadian rhythms.”
To address these challenges, the researchers used tiny glass tubes to isolate individual cells from developing plants and analyzed the expression of various genes related to circadian rhythms and cell differentiation in each cell. They then developed a new algorithm called PeakMatch to reconstruct actual-time gene expression patterns from the single-cell datasets.
“Using this powerful approach, we were able to show that the expression profile of clock genes is changed prior to cell differentiation,” states Endo. “Specifically, in early differentiating cells, the induction of the clock gene LUX ARRYTHMO directly targets genes involved in cell-cycle progression to regulate cell differentiation.”
Further investigation showed that large-scale changes in the circadian clock profile in undifferentiated cells induce the expression of the clock gene LUX, which directly triggers cell differentiation.
“Taken together, our results show that the plant circadian clock plays a guiding role in cell differentiation,” says Endo. “Importantly, our study also provides an approach for time-series analysis at single-cell resolution.”
Because the development of circadian rhythms during cell differentiation is observed in animals as well as in plants, the finding that clock genes directly regulate cell fate determination and cell division may help understand how cell differentiation is controlled in multicellular organisms. The newly developed PeakMatch algorithm can also be applied to all kinds of single-cell transcriptomes in other organisms.
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Shared micromobility programs for e-scooters and bike share are becoming more common each year. How can we make sure they aren’t just being used for fun, but they’re also being prioritized for those who need a quick, affordable and accessible way to get around? A team of researchers has collected documentation about equity requirements from 239 shared micromobility programs across the U.S. and compiled all the data into an online dashboard, which city officials can use to find what other similar-sized cities are doing. Equity efforts in one city may pave the way for expanded opportunities in another.
Keeping a focus on equity can make this new technology accessible and affordable, and could improve the lives of people with disabilities, people with low incomes, those who don’t have access to a smartphone, and those who live in neighborhoods without good transit access. Led by the University of Oregon’s Anne Brown and Amanda Howell, with Hana Creger of The Greenlining Institute, the latest report from the National Institute for Transportation and Communities (NITC) took steps toward operationalizing equity in these programs: In other words, making it simple for cities, agencies and mobility providers to ensure their e-scooter and bike share programs serve the communities who most need them.
“Our hope is, for companies or cities that are starting a new program, they can use the dashboard and find specific language for equity requirements in other comparable cities. Micromobility companies are now going to smaller communities, but their staff often don’t have the bandwidth to study in depth what other places are doing,” Brown said.
Filters in the dashboard let the user sort by mode, city population size, and specific program requirements. Rather than reinvent the wheel, cities looking to introduce a new program or rethink their existing micromobility service can quickly scan the dashboard and get detailed information about reduced fare programs, geographical distribution, adaptive vehicles, cash payment options, smartphone alternatives, targeted marketing and outreach, and multilingual services.
The researchers also created a Shared Micromobility Equity Evaluation Tool, which lets equity program managers see their equity “score” in three key areas: process, implementation, and evaluation.
So What Are Cities Doing for Equity, as of Now?
Researchers found that equity requirements were common, but far from universal. Of the 239 programs they studied, 149 of them (about 62%) had requirements related to equity. Other cities and agencies had language recommending, encouraging, or stating that equity-based program elements were desirable, but did not require that operators implement them. More

Rare earth metals, when linked, can act as a conduit for energy flow, and show promise for the development of novel materials.
Scientists have connected two soft crystals and observed energy transfer between them — a finding that could lead to the development of sophisticated, responsive materials. The study, by scientists at Hokkaido University in Japan, was published in the journal Nature Communications.
Soft crystals are flexible molecular solids with highly ordered structures. When they are subjected to external stimuli, such as vapour or rubbing, their molecular structures get reordered and they respond by changing shape, colour or luminescence.
“We wanted to know what would happen if we merged soft crystals at the molecular level to connect them,” says Yasuchika Hasegawa, a materials chemist at Hokkaido University and lead author of the study. Hasegawa and his team used rare earth metals called lanthanides, whose ions have similarly large radii and therefore form similar structures. Lanthanide compounds, of which there are 15, are interesting because they can luminesce.
The team studied the structures of crystals made from the lanthanides terbium (Tb), which luminesces green, and dysprosium (Dy), which luminesces yellow. The team first linked the crystals of each lanthanide separately and observed the structures and energy transfer within the compounds. They then used this information to merge Tb(III) and Dy(III) crystals together through a pyridine bond and examined the molecular structure of an energy transfer within the merged ‘molecular train’.
When they excited the dysprosium end of the train using blue light, they observed green luminescence at the opposite terbium end. Their calculations revealed energy was transferred from one crystal to the other over a distance of 150 micrometres. “This energy migration distance is the longest reported for lanthanide coordination polymers or complex systems,” says Hasegawa. The terbium end continued to luminescence for 0.60 milliseconds.
Connecting soft crystals could lead to the formation of novel crystal structures that could have applications in semiconductors, lasers, optical fibres and printing.
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In the American action movie “Pacific Rim,” giant robots called “Jaegers” fight against unknown monsters to save humankind. These robots are equipped with artificial muscles that mimic real living bodies and defeat monsters with power and speed. Recently research is being conducted on equipping real robots with artificial muscles like the ones shows in the movie. However, the powerful strength and high speed in artificial muscles cannot be actualized since the mechanical strength (force) and conductivity (speed) of polymer electrolyte — the key materials driving the actuator — have conflicting characteristics.
A POSTECH research team led by Professor Moon Jeong Park, Professor Chang Yun Son, and Research Professor Rui-Yang Wang from the Department of Chemistry has developed a new concept of polymer electrolyte with different functional groups located at a distance of 2Å. This polymer electrolyte is capable of both ionic and hydrogen bonding interactions, thereby opening the possibility of resolving these contradictions. The findings from this study have been recently published in the international academic journal Advanced Materials.
Artificial muscles are used to make robots move their limbs naturally as humans can. To drive these artificial muscles, an actuator that exhibits mechanical transformation under low voltage conditions is required. However, due to the nature of the polymer electrolyte used in the actuator, strength and speed could not be achieved simultaneously because increasing muscle strength slows down the switching speed and increasing speed reduces the strength.
To overcome the limitations presented so far, the research introduced the innovative concept of bifunctional polymer. By forming a one-dimensional ion channel several nanometers wide inside the polymer matrix, which is hard as glass, a superionic polymer electrolyte with both high ionic conductivity and mechanical strength was achieved.
The findings from this study have the potential to create innovations in soft robotics and wearable technology as they can be applied to development of an unprecedented artificial muscle that connects a portable battery (1.5 V), produces fast switching of several milliseconds (thousandths of a second), and great strength. Furthermore, these results are expected to be applied in next-generation all-solid-state electrochemical devices and highly stable lithium metal batteries.
This study was conducted with the support from the Samsung Science and Technology Foundation.
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A research team led by Professor Seo Dae-ha of the Department of Physics and Chemistry at DGIST (President Kuk Yang) developed an optical microscopy that can control and observe electron transfer and transfer in complex chemical reactions occurring in nano-catalysts. This technology is expected to provide an experiment strategy based on system chemistry, a new experiment strategy for precisely studying photocatalysts at the single particle level.
Plasmonic metals at the nanometer level, such as gold, exhibit high light absorption rate in a wide place within the range of visible light. They are combined with semiconductor photocatalysts to act as a medium to increase light absorption. Excitation occurs in which electrons gain energy and move as a reaction to light absorption, and it appears through various paths depending on the size of the metal and the wavelength of the light. There are various hypotheses on the effect of this electron movement as a catalyst. The research team was able to test the hypotheses and reveal how electrons transfer by developing a new microscope that is experimentally simpler and more sophisticated than the conventional method of observing chemical reactions.
Professor Seo Dae-ha’s research team developed hybrid nanoparticles (for example, ‘gold/copper oxides’, a combination of gold and copper oxides), and lasers of different wavelengths (colors) (i.e., lasers A, B, and C are A+B, A+C … A+B+C) were combined into a new form, respectively, to investigate the reaction between them to test various hypotheses on the electron excitation phenomenon through experiments and verify them one by one. Through this process, the team was able to selectively induce electron excitation in gold nanoparticles, and quantitatively analyze their contributions by evaluating the increase in the reactivity of the catalyst. In addition, the team confirmed that these excited electrons were transferred to the semiconductor to increase stability and reactivity at the same time.
“The observational technology reported here is a technology that observes chemical reactions with high precision, efficiency, and low cost,” said Professor Seo Dae-ha of the Department of Physics and Chemistry at DGIST, while adding, “It is expected that it will contribute to the sophisticated design of catalysts and will be applied as a sophisticated evaluation and control technology using nanoparticles for pharmaceuticals.”
Meanwhile, this research was carried out with support of the National Research Foundation’s Leading Researcher Support Project, Leading Research Center, Biomedical Technology Development Project, and DGIST’s Grand Challenge Research Innovation Project.
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Materials provided by DGIST (Daegu Gyeongbuk Institute of Science and Technology). Note: Content may be edited for style and length. More

Topology and entanglement are two powerful principles for characterizing the structure of complex quantum states. In a new paper in the journal Physical Review X, researchers from the University of Pennsylvania establish a relationship between the two.
“Our work ties two big ideas together,” says Charles Kane, the Christopher H. Browne Distinguished Professor of Physics in Penn’s School of Arts & Sciences. “It’s a conceptual link between topology, which is a way of characterizing the universal features that quantum states have, and entanglement, which is a way in which quantum states can exhibit non-local correlations, where something that happens in one point in space is correlated with something that happens in another part in space. What we’ve found is a situation where those concepts are tightly intertwined.”
The seed for exploring this connection came during the long hours Kane spent in his home office during the pandemic, pondering new ideas. One train of thought had him envisioning the classic textbook image of the Fermi surface of copper, which represents the metal’s potential electron energies. It’s a picture every physics student sees, and one with which Kane was highly familiar.
“Of course, I learned about that picture back in the 1980s but had never thought about it as describing a topological surface,” Kane says.
A classic way of thinking about topological surfaces, says Kane, is to consider the difference between a donut and a sphere. What’s the difference? A single hole. Topology considers these generalizable properties of a surface, which are not changed by deformation. Under this principle, a coffee cup and a donut would have the same topological property.
Considering the Fermi surface of copper as a topological object, then, the associated number of holes it possesses is four, a figure also known as a genus. Once Kane began thinking of the Fermi surface in this way, he wondered whether a relationship could exist between the genus and quantum entanglement. More