Computers Math

The emergence of distributed energy resources (DERs) — facilities owned by individuals or small companies that can generate, store and return power to energy grids — is transforming the way power is used across the world.
The technology is becoming more prevalent as society looks for alternative sources of energy, but its rapid growth brings with it a new field of vulnerabilities open to cyberattacks.
DERs like home-based solar panels or electric vehicle chargers rely on field devices known as smart inverters to interface with power grids. As a new study by Concordia researchers shows, these devices’ reliance on digital information and communication technology can be attacked in multiple ways by malicious actors, with serious repercussions for the public.
The paper, published in the IEEE: Transactions on Power Electronics journal, surveys the landscape of smart inverter cybersecurity and identifies attack strategies at the device and grid level. It also looks at ways to defend against, mitigate and prevent them.
“We are still in the first decade of trying to understand the problem and identifying the most prominent risks,” says the paper’s co-author Jun Yan, associate professor at the Concordia Institute for Information Systems Engineering.
“Threats are inevitable. We have so many homeowners and third parties using these devices that having a perfect line of defence is impossible. We must look at our strategic priorities to start.”
Yuanling Li, a Concordia PhD student and research intern at Ericsson’s Global Artificial Intelligence Accelerator (GAIA), is the paper’s lead author. More

Silicon carbide (SiC) is a semiconductor material that outperforms pure silicon-based semiconductors in several applications. Used mostly in power inverters, motor drives, and battery chargers, SiC devices offer benefits such as a high power density and reduced power losses at high frequencies even at high voltages. Although these properties and its relatively low cost make SiC a promising contender in various sectors of the semiconductor market, its poor long-term reliability has been an insurmountable barrier since the past two decades.
One of the most pressing issues with 4H-SiC -a SiC type with superior physical properties- is bipolar degradation. This phenomenon is caused by the expansion of stacking faults in 4H-SiC crystals. Put simply, small dislocations in the crystal structure grow over time into large defects called “single Shockley stacking faults” that progressively degrade performance and cause the device to fail. Although some methods to mitigate this problem exist, they make the device fabrication process more expensive.
Fortunately, a team of researchers from Japan led by Associate Professor Masashi Kato from the Nagoya Institute of Technology, have now found a feasible solution for this issue. In their study made available online on 5 November 2022 and published in the journal Scientific Reports on 5 November 2022, they present a fault suppression technique called “proton implantation” that can prevent bipolar degradation in 4H-SiC semiconductor wafers when applied prior to the device fabrication process. Explaining the motivation for this study, Dr. Kato says, “Even in the recently developed SiC epitaxial wafers, bipolar degradation persists in the substrate layers. We wanted to help the industry navigate this challenge and find a way for developing reliable SiC devices, and, therefore, decided to investigate this method for eliminating bipolar degradation.” Associate professor Shunta Harada from Nagoya University, and Hitoshi Sakane, an academic researcher from SHI-ATEX, both in Japan, were also part of this study.
Proton implantation involves “injecting” hydrogen ions into the substrate using a particle accelerator. The idea is to prevent the formation of single Shockley stacking faults by pinning down partial dislocations in the crystal, one of the effects of introducing proton impurities. However, proton implantation itself can damage the 4H-SiC substrate, due to which high-temperature annealing is used as an additional processing step to repair this damage.
The research team wanted to verify if proton implantation would be effective when applied before the device fabrication process, which typically includes a high-temperature annealing step. Accordingly, they applied proton implantation at different doses on 4H-SiC wafers and used them to fabricate PiN diodes. They then analyzed the current-voltage characteristics of these diodes and compared them to those of a regular diode without proton implantation. Finally, they captured electroluminescence images of the diodes to check whether stacking faults had formed or not.
Overall, the results were very promising as diodes that had undergone proton implantation performed just as well as regular ones but without signs of bipolar degradation. The deterioration of the current-voltage characteristics of the diodes caused by proton implantation at lower doses were not significant. However, the suppression of the expansion of single Shockley stacking faults was significant.
The researchers hope that these findings will help realize more reliable and cost-effective SiC devices that can reduce power consumption in trains and vehicles. “Although the additional fabrication costs of proton implantation should be considered, they would be similar to those incurred in aluminum-ion implantation, currently an essential step in the fabrication of 4H-SiC power devices.” speculates Dr. Kato. “Moreover, with further optimization of implantation conditions, there is a possibility of applying this method for the fabrication of other kinds of devices based on 4H-SiC.”
Hopefully, these findings will help unlock the full potential of SiC as a semiconductor material for powering next-generation electronics.
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Walking can boost not only your own energy but also, potentially, the energy of your wearable electronic devices. Osaka Metropolitan University scientists made a significant advance toward self-charging wearable devices with their invention of a dynamic magnifier-enhanced piezoelectric vibration energy harvester that can amplify power generated from impulsive vibrations, such as from human walking, by about 90 times, while remaining as small as currently developed energy harvesters. The results were published in Applied Physics Letters.
These days, people carry multiple electronic devices such as smartphones, and wearable devices are expected to become increasingly widespread in the near future. The resulting demand for more efficient recharging of these devices has increased the attention paid to energy harvesting, a technology that converts energy such as heat and light into electricity that can power small devices. One form of energy harvesting called vibration energy harvesting is deemed highly practical given that it can transform the kinetic energy from vibration into electricity and is not affected by weather or climate.
A research team led by Associate Professor Takeshi Yoshimura from the Graduate School of Engineering at Osaka Metropolitan University has developed a microelectromechanical system (MEMS) piezoelectric vibration energy harvester that is only approximately 2 cm in diameter with a U-shaped metal component called a dynamic magnifier. Compared with conventional harvesters, the new harvester allows for an increase of about 90 times in the power converted from impulsive vibrations, which can be generated by human walking motion.
The team has been working on developing vibration energy harvesters that utilize the piezoelectric effect, a phenomenon in which specific types of materials produce an electric charge or voltage in response to applied pressure. So far, they have succeeded in generating microwatt-level electricity from mechanical vibrations with a constant frequency, such as those generated by motors and washing machines. However, the power generation of these harvesters drops drastically when the applied vibrations are nonstationary and impulsive, such as those generated by human walking.
Responding to this challenge, the team developed and incorporated the U-shaped vibration amplification component under the harvester. The component allowed for improvement in power generation without increasing the device size. The technology is expected to generate electric power from non-steady vibrations, including walking motion, in order to power small wearable devices such as smartphones and wireless earphones.
Professor Yoshimura concluded, “Since electronic devices are expected to become more energy-efficient, we hope that this invention will contribute to the realization of self-charging wearable devices.”
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Researchers at LMU and Charité hospital in Berlin have developed a method for classifying difficult-to-diagnose nasal cavity tumors.
Although tumors in the nasal cavity and the paranasal sinus are confined to a small space, they encompass a very broad spectrum with many tumor types. As they often do not exhibit any specific pattern or appearance, they are difficult to diagnose. This applies especially to so-called sinonasal undifferentiated carcinomas (SNUCs).
Now a team led by Dr. Philipp Jurmeister and Prof. Frederick Klauschen from the Institute of Pathology at LMU and Prof. David Capper from Charité University Hospital as well as the German Cancer Consortium (DKTK) ), partner sites Munich and Berlin, has achieved a decisive improvement in diagnostics. The team developed an AI tool that reliably distinguishes tumors on the basis of chemical DNA modifications and assigns the SNUCs, which the methods available before now have been unable to distinguish, to four clearly distinct groups. This breakthrough could open up new opportunities for targeted therapies.
Tumor-specific DNA modifications
Chemical modifications in DNA play a vital role in the regulation of gene activity. This includes DNA methylation, whereby an extra methyl group is added to the DNA building blocks. In earlier studies, the scientists had already demonstrated that the methylation pattern of the genome is specific for different tumor types, because it can be traced back to the tumor’s cell of origin.
“On this basis, we’ve now recorded the DNA methylation patterns of almost 400 tumors in the nasal cavity and paranasal sinus,” says Capper. Thanks to an extensive international collaboration, the researchers managed to compile such a large number of samples even though these tumors are rare and comprise only about four percent of all malignant tumors in the nose and throat area.
Four tumor groups with different prognoses
For the analysis of the DNA methylation data, the researchers have developed an AI model that assigns the tumors to different classes. “Due to the large volumes of data involved, machine learning methods are indispensable,” says Jurmeister. “To actually recognize patterns, we had to evaluate several thousand methylation positions in our study.” This revealed that SNUCs can be classified into four groups, which also differ in terms of further molecular characteristics.
Furthermore, these results are clinically relevant, as the various groups have different prognoses. “One group takes a surprisingly good course, for example, even though the tumors look very aggressive under the microscope,” says Klauschen. “Whereas another group has a poor prognosis.” On the basis of the molecular characteristics of the groups, researchers may also be able to develop targeted new therapy approaches in the future.
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Materials provided by Ludwig-Maximilians-Universität München. Note: Content may be edited for style and length. More

As machine-learning models become larger and more complex, they require faster and more energy-efficient hardware to perform computations. Conventional digital computers are struggling to keep up.
An analog optical neural network could perform the same tasks as a digital one, such as image classification or speech recognition, but because computations are performed using light instead of electrical signals, optical neural networks can run many times faster while consuming less energy.
However, these analog devices are prone to hardware errors that can make computations less precise. Microscopic imperfections in hardware components are one cause of these errors. In an optical neural network that has many connected components, errors can quickly accumulate.
Even with error-correction techniques, due to fundamental properties of the devices that make up an optical neural network, some amount of error is unavoidable. A network that is large enough to be implemented in the real world would be far too imprecise to be effective.
MIT researchers have overcome this hurdle and found a way to effectively scale an optical neural network. By adding a tiny hardware component to the optical switches that form the network’s architecture, they can reduce even the uncorrectable errors that would otherwise accumulate in the device.
Their work could enable a super-fast, energy-efficient, analog neural network that can function with the same accuracy as a digital one. With this technique, as an optical circuit becomes larger, the amount of error in its computations actually decreases. More

Previously, very little was known about online gaming behaviour based on the actual games played and how career interests are reflected in what people play. To examine this correlation, in collaboration with Game Academy Ltd, Surrey researchers investigated the gaming behaviour of 16,033 participants to explore how the hobby could support video game players’ future career planning and professional training.
The participants played a different number of games on Steam — a video game digital distribution service and storefront. Researchers studied the 800 most-played games and only included participants for whom they had access to gender and job details.
Researchers discovered that IT professionals and engineers played puzzle-platform games, which possibly enhance their spatial skills. People in managerial roles showed an interest in action roleplay games where organisational and planning skills are involved and engineering professionals were associated with strategy games which often require problem-solving and spatial skills. There were apparent gender differences too — females preferred playing single-player games, whereas males preferred playing shooting games.
Dr Anna-Stiina Wallinheimo, lead author of the study, Cognitive Psychologist, and Postdoctoral Research Fellow at the University of Surrey’s Centre for Translation Studies (CTS) said:
“In recruitment processes, the best candidates may be missed because organisations do not consider the soft skills that have been gained through non-work activities (for example, online gaming). As a result of our research, we believe applicants’ online gaming experiences should be highlighted because these acquired soft skills can really help to develop their all-round strengths for the job at hand.”
Dr Anesa Hosein, co-author of the study and Associate Professor in Higher Education at the University of Surrey said:
“By understanding to what extent career interests are reflected in game playing, we may be able to demonstrate more clearly how these align with career interests and encourage employers to understand the value of the soft skills associated with gaming. Our research could also inspire game developers to work on honing these soft skills more closely in their design. Furthermore, places of learning, such as universities, could allow students to reflect and incorporate gaming as part of their career development and consider how gaming can be included in the curriculum to enhance alignment between students’ learning, career aspirations and extra-curricular gaming interests.”
This research was published in SAGE Journals.
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In recent years, research and development on quantum computers has made considerable progress. Quantum chemical calculations for electronic structures of atoms and molecules are attracting great attention as one of the most promising applications of quantum computers. In order to utilize quantum chemical calculations for chemistry and related fields, it is essential to develop geometry optimization methods for finding the most stable structure of molecules. The geometry optimization requires calculations of energy derivatives with respect to nuclear coordinates of molecules.
The finite difference method is one approach for energy derivative calculations. On a classical computer, calculations based on this method for one-dimensional systems require at least two evaluations of the energy. Previous research has shown that a quantum computer, in contrast, requires only a single query to calculate the energy derivatives based on the finite difference method, regardless of the number of degrees of freedom. However, quantum circuits relevant to quantum algorithms capable of performing energy derivative calculations have not been implemented.
A research group including Dr. Kenji Sugisaki, Professor Kazunobu Sato, and Professor Emeritus Takeji Takui from the Graduate School of Science at Osaka Metropolitan University has successfully extended the quantum phase difference estimation algorithm, a general quantum algorithm for the direct calculations of energy gaps, to enable the direct calculation of energy differences between two different molecular geometries. This allows for the computation, based on the finite difference method, of energy derivatives with respect to nuclear coordinates in a single calculation.
Furthermore, the research group has applied the developed energy derivative calculations to execute geometry optimizations of H2, LiH, BeH2, and N2 molecules without calculating the total energies, demonstrating the usefulness of the developed method. The group also discussed how quantum circuits can be assembled according to different degrees of freedom of the molecules.
This research is the latest in a series of the researchers’ articles on quantum chemical calculations on quantum computers. “Our latest findings bring us one step closer to applying quantum chemical calculations on a quantum computer to real-world problems,” said Dr. Sugisaki. “Since energy derivative calculations are used for not only molecular geometry optimizations but also various calculations for molecular properties, the application of our method is expected to play a very important role in a wide range of related fields, such as in silico drug discovery/design and materials development.”
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Imagine walking into an ice cream shop and scanning your options. A sugar cone with one scoop is $3. A second scoop comes out to $4, but for just 50 cents more, you can get a large waffle cone with three scoops. Some people may not want that much ice cream. But for many, it’s hard to pass up a good deal.
Adding a third option to make something else (usually the higher priced item) more attractive is a common marketing strategy. But since the 1980s, scholars have been debating whether this attraction effect via a “decoy option” actually works in real-life settings.
Findings from a new, in-depth study bolster the argument that decoy options can shift consumer preferences. It’s also the first to test this approach in digital markets where billions of people make choices every day.
The researchers randomly assigned 4,000 participants to eight experiments based on reward-based crowdfunding campaigns, including one on Kickstarter with a real Swiss watchmaking company. Their findings, published in Information Systems Research, show the attraction effect shifted preferences from a low-priced to a high-priced reward by as much as 28%.
“That’s a significant jump that can turn an entrepreneur’s project into a reality,” said Abhay Mishra, associate professor of information systems and business analytics at Iowa State University and co-author of the study. “Our findings can help inform artists, innovators and creatives to make smarter, more effective reward menus to reach their fundraising goals.”
In reward-based crowdfunding markets, entrepreneurs set a fundraising target with a deadline for their project. Backers choose from several reward menu options, pledging a certain amount of money to receive a product or sample of the to-be-funded project. Whether the entrepreneur gets any of the funding and the backers receive their rewards depends on the project successfully reaching the fundraising goal by the set date. More