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Thursday, August 13, 2026

 


New AI model predicts extreme temperature events with unprecedented accuracy



Science China Press





Extreme temperature events are becoming more frequent and intense as climate change accelerates. Yet predicting these abrupt, non-stationary phenomena remains a fundamental challenge for conventional time series models, which often fail to capture rapid transitions and anomalous patterns that deviate significantly from historical behaviors.

Now, researchers from the Hangzhou Institute for Advanced Study at the University of Chinese Academy of Sciences have developed Hankelformer, a novel deep learning architecture that dramatically improves the forecasting of extreme weather events. The findings are published in National Science Review.

Hankelformer introduces two key innovations. First, it employs a structured augmentation module that constructs Hankel matrices to capture local spatiotemporal dynamics without disrupting temporal coherence, generating delay-embedding-inspired views that are topologically equivalent to the original input sequences. Second, it uses a dual-stream contrastive learning framework in which both the original and augmented sequences are processed through shared-weight Transformer encoders, maximizing agreement between the two representations. This approach significantly enhances feature invariance and robustness against distribution shifts.

The team evaluated Hankelformer on nine benchmark datasets spanning energy, transportation, and extreme weather domains. On three custom datasets capturing real-world extreme events—the 2021 Texas winter storm (TexasFreeze), the 2021 Pacific Northwest heat dome (Heatwave), and the 2020 Antarctic Peninsula heat event (Antarctic Heat)—Hankelformer consistently achieved state-of-the-art performance. Compared to leading baselines, the model delivered up to 34% improvement in Mean Squared Error (MSE).

In validation tests on a 90-dimensional chaotic Lorenz system, Hankelformer demonstrated exceptional noise robustness, maintaining low prediction error even under strong Gaussian noise interference. Ablation studies confirmed that both the Hankel augmentation and the contrastive learning components are essential: using augmentation without the contrastive loss actually degraded performance, highlighting the critical role of contrastive learning in aligning heterogeneous representations and stabilizing optimization.

The success of Hankelformer provides a promising tool for reliable extreme temperature forecasting and underscores the value of constructing topologically equivalent sequences for spatiotemporal representation learning in handling real-world non-stationary time series. Beyond climate monitoring, the framework shows potential for applications in energy system management, traffic flow prediction, and other safety-critical domains where prediction failures can have severe consequences.

 

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Predicting the ocean with AI in the age of the climate crisis

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An evaluation of El Niño development responses based on KIST-Ocean simulations using initial conditions from May 3, 2015, when the past Super El Niño began to develop.

(Left) When wind stress from 2015 was input, the simulation successfully reproduced the development of the past Super El Ni?o, with rising sea surface temperatures in the central to eastern Pacific.

(Right) When prescribing normal-year wind stress unrelated to El Niño development, no El Niño development occurred; instead, a La Niña response was observed, characterized by a decline in sea surface temperatures.


The results of the KIST-Ocean experiments are consistent with previous studies indicating that wind stress in the tropical Pacific plays a major role in the development of a super El Niño, demonstrating that KIST-Ocean possesses excellent physical fidelity.

Credit

(Left) Phase speed of oceanic Rossby waves observed in KIST-Ocean when artificial wind stress is applied to the equatorial Pacific. The x-axis denotes the latitude at which the wind stress was imposed. The y-axis shows the phase speed predicted by KIST-Ocean together with the corresponding theoretical values (shown in red), which vary with latitude. Each data point represents the results of multiple predictions performed at that latitude to ensure statistical significance.

Credit

What do people really think about generative AI?

Longitudinal study of Reddit posts since 2022 shows persistent tension between trust and distrust in generative AI




Drexel University






Is generative artificial intelligence technology a helpful tool or a big problem? Nearly four years after ChatGPT became a household name, most people are either using AI applications or generally aware of what the technology can do. But understanding how much they actually trust the work it produces, and the answers it provides, remains an important question. New research from Drexel University, based on a longitudinal analysis of hundreds of thousands of Reddit posts since 2022, sheds light on the general perception of AI and suggests that the public remains largely divided on how much it can be trusted.

Recently published in the journal Transactions of the Association for Computational Linguistics, the study examined how trust and distrust toward generative AI were expressed over time, the dimensions and reasons underlying these attitudes and how these patterns differed across groups represented in the posts.

Its primary finding is that trust, which was expressed in about 31% of posts, modestly outpaced distrust (26%) in the technology, while 41% of posts expressed neither and 1% expressed both.

Across the study period from 2022 to 2025, trust generally maintained this modest lead, although the balance fluctuated and distrust briefly surpassed trust during some periods. Despite a steady flow of new models and applications, the overall pattern suggests that attitudes expressed in these Reddit communities toward generative AI have remained divided, rather than moving steadily toward either trust or distrust. The findings stand in contrast to recent reports that suggest that while more people are using the technology, they do not trust it and trust has been declining.

“These findings give us an important starting point and help to establish a baseline understanding which can help inform responsible AI design, governance and literacy efforts,” said Shadi Rezapour, PhD, an assistant professor in the Nick Howley College of Engineering and Computing, who led the research. “It will be important to see how these attitudes around trust and distrust evolve as the technology becomes more widely used.”

In what is believed to be the first large-scale, longitudinal study of how attitudes of trust and distrust in AI have evolved over the last four years, Rezapour’s research group in the School of Computer and Information Sciences, joined by researchers from Drexel’s College of Arts and Sciences and LeBow College of Business, gathered and analyzed more than 230,000 posts from 39 AI-related subreddits between November 2022 and June 2025. They looked at posts expressing views on systems such as ChatGPT, LLaMA, Claude and other widely discussed GenAI tools.

What does it mean to ‘trust’ AI?

“We defined trust as a belief that Generative AI is reliable, competent or acts with integrity, leading people to have positive expectations about its performance or behavior,” said Aria Pessianzadeh, a doctoral candidate in the School of Computer and Information Sciences, and lead author of the study. “Distrust is more than simply the absence of trust. It reflects active skepticism or concern about the technology’s reliability, competence or ethical implications, which can lead to negative expectations or more cautious behavior.”

In addition to trust and distrust, and their dimensions, to better understand how these attitudes vary between different groups of people, the team broke down the type of commenter, or “trustor,” represented in each post into 10 categories using self-identifying information from their posts: generative AI users, software developers, researchers or academics, tech industry professionals, general public, media and journalists, business leaders or executives, AI ethicists or advocacy groups, artists or creatives and educators or knowledge workers.

Using computational models, the researchers analyzed the large volume of Reddit posts and categorized them based on the trust or distrust expressed and the reasons behind those views.

Views of trust tended to outweigh distrust among business leaders, academics, software developers and tech professionals. Distrust was more frequently expressed among posts categorized as representing the general public, AI ethicists and media and journalists. Generative AI users, which were the largest group, along with educators and knowledge workers, showed a relatively balanced level of trust and distrust, the study reported.

How do people form opinions about AI?

One theme that persisted across user groups was that personal experience with AI was the most frequently expressed reason underlying both trust and distrust. People also tended to express their views in terms of technological efficacy and reliability of the output, rather than ethical or normative aspects of the technology, such as judgments associated with a program’s relative transparency or integrity.

“What stood out was how practical people’s judgments of AI tended to be,” Pessianzadeh said. “They were primarily asking: ‘Does it work? Is it accurate? Can I rely on it?’ Competence, reliability and familiarity were central to expressions of trust, while unreliability and incompetence were major sources of distrust. Ethical and value-oriented concerns were certainly present, but they were much less prominent in everyday discussions. For many users, trust in AI is expressed primarily in relation to their direct experience with what these systems can actually do, suggesting that people are more focused on whether AI programs ‘work’ than whether the technology is ‘good.’”

Some of the clearest fluctuations in trust and distrust occurred around periods when the researchers observed the public release of new AI products, such as GPT-4 and LLaMA 2, as well as major announcements, such as OpenAI’s Dev Day. Around several major releases in 2023, the monthly share of posts expressing trust increased modestly. By contrast, distrust increased around OpenAI’s Dev Day in late 2023.

“Despite these fluctuations, trust maintained its modest lead over distrust. However, neither category dominated the discourse, underscoring a persistent tension in attitudes expressed in GenAI discourse,” the researchers reported in the study.

How to Move Forward

Acknowledging this co-existence of trust and distrust will be important, the researchers suggest, as regulators set up governance and design standards to ensure safe use of the technology.

“A persistent duality like this means that responsible governance of the technology should consider that users will include both those who are confident in AI as well as those who are skeptical,” said Rezapour. “Our findings also suggest that governance cannot focus only on whether people find AI useful. It should address questions of reliability, transparency, bias and accountability in ways that connect these concerns to people's everyday experiences with the technology.”

The researchers note that although this is a large-scale study, the fact that all of its data was drawn from Reddit posts could be a limiting factor. The relatively low prominence of ethical dimensions simply may be a reflection of how people communicate on social media – emphasizing immediate experiences of usefulness and performance, while broader ethical or normative concerns may be expressed less explicitly or require more contextual interpretation, according to the researchers.

They recommend that future research broaden the dataset to include languages other than English, additional social media platforms and populations beyond the online communities represented in the current study.

“These findings are a useful starting point, but trust in AI is not static and people’s attitudes change based on their experiences with these systems, new capabilities and major developments in the technology,” Rezapour said. “Therefore, researchers should continue to examine how attitudes about AI technology evolve in the coming years. With the rapidity of its adoption, it’s understandable that perceptions will be divided for some time. As these systems become increasingly embedded in everyday life, it will be important to understand whether trust and distrust continue to fluctuate, and what experiences, capabilities and broader developments drive those changes.”

 

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When AI enters the physical world, safety gets real

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Teaching AI the biology of antibodies speeds drug discovery




Boston University
Molecule 

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A 3D molecular view of an antibody, shown in cyan and green, binding to its target antigen, shown in magenta.

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Credit: Diane Joseph-McCarthy/Boston University





Designing an effective antibody drug is like searching for the right key in a warehouse of locks. Scientists may begin with millions—or even billions—of antibody candidates, but only a tiny fraction will recognize and bind tightly to the disease target. Identifying those rare candidates has long been one of the biggest challenges in developing antibody medicines. 

Boston University researchers have now developed an antibody-specific AI framework that dramatically narrows that search. Rather than building a larger AI model, the team redesigned how AI learns, focusing it on the small regions of antibodies that recognize disease targets. 

"Instead of treating antibodies like generic proteins, we designed an antibody-specific language model that learns the fundamental patterns in the regions responsible for antigen binding," says Diane Joseph-McCarthy, PhD, the study's principal investigator and executive director of Boston University’s Bioengineering Technology & Entrepreneurship Center. "That focused approach helps researchers identify the most promising therapeutic candidates before they ever enter the laboratory." 

The study was published today in the Nature Portfolio journal Communications AI & Computing. Researchers found that the approach improved predictions of antibody binding strength, known as binding affinity, by as much as 27 percent while requiring far fewer computational resources than many existing antibody AI models.

Why Antibodies Challenge AI 

Artificial intelligence has transformed biology by identifying patterns across millions of protein sequences. Like ChatGPT predicts missing words, protein language models predict masked amino acids to learn the "language" of proteins. 

For most proteins, randomly hiding amino acids throughout a sequence is an effective training strategy because biologically important information is distributed across the molecule. Reconstructing the missing pieces helps the model discover the patterns that determine protein structure and function. 

Antibodies, however, are different. 

The regions responsible for recognizing viruses, bacteria, and cancer cells continually evolve so the immune system can adapt to new threats. That diversity makes antibodies extraordinarily powerful—and more difficult for AI to model. 

Most of an antibody serves as a structural scaffold. The information that determines what an antibody recognizes and how tightly it binds is concentrated within six tiny loops called complementarity-determining regions, or CDRs. 

"Think of an antibody like a screwdriver," says John Misasi, MD, a study co-author and assistant professor of virology, immunology, and microbiology at Boston University’s Chobanian and Avedisian School of Medicine. "It doesn't matter whether it's long or short—the shape of the tip determines what kind of screw it fits. The CDRs are like that tip: they determine which target the antibody recognizes." 

Teaching AI the Biology That Matters 

Recognizing that antibodies break many of the assumptions behind general protein language models, the researchers redesigned the training process around antibody biology instead of treating every amino acid as equally important. 

The model focused its learning on the CDRs—the regions directly responsible for recognizing disease targets—and was trained using more than 1.6 million naturally paired antibody heavy and light chains that together form the binding site. During training, the researchers deliberately masked up to half of the amino acids within the CDRs while leaving most of the surrounding antibody structure intact, repeatedly challenging the AI to reconstruct the regions most critical for binding. 

"A lot of AI research has focused on building larger models," says Ioannis (Yannis) Paschalidis, PhD, a co-author of the study and director of Boston University’s Hariri Institute for Computing. "We asked a different question: How can we teach the model the biology that matters most? That turned out to be a much more effective strategy." 

The result was a smaller, more focused model containing about 600 million parameters that matched or outperformed much larger antibody language models on multiple benchmark tests. It improved binding affinity prediction by as much as 27 percent across datasets containing more than 90,000 engineered antibody variants targeting six different antigens. By training on millions rather than billions of antibody sequences, it required substantially less computational effort. 

"One of the exciting findings is that we didn't need a larger model or vastly more data,” says Paschalidis. "That’s similar to what's been observed with human-language AI models, where smaller domain-specific models trained on high-quality data can often outperform much larger, more general ones." 

The approach emerged from a convergent research effort that brought together expertise in artificial intelligence, immunology, structural biology, and experimental science—not simply to apply AI to biology, but to redesign how AI learns using biological knowledge. 

From Prediction to Prioritization 

The study addresses one of the biggest bottlenecks in antibody discovery: deciding which candidates to test. Even small changes to an antibody's sequence can create trillions of possible variants—far more than laboratories can realistically evaluate experimentally. The model helps narrow those possibilities before laboratory testing, reducing unnecessary experiments and accelerating antibody optimization. 

"Knowing not just whether an antibody binds, but how strongly it binds, gives researchers a much better starting point for deciding which candidates to move forward," says Misasi, core faculty at BU’s National Emerging Infectious Diseases Laboratories (NEIDL). "If a computer can narrow millions of possibilities down to the few hundred most promising candidates, that saves an enormous amount of time, labor, and cost in the laboratory." 

Beyond selecting antibody candidates for testing, the approach could improve antibody engineering. Researchers could use the model to predict which sequence changes are most likely to strengthen existing antibodies, helping optimize therapies against evolving viruses or other disease targets before moving those designs into experimental testing. 

"If another infectious disease outbreak occurs, we'd like to identify promising antibody candidates as quickly as possible," says Misasi. "Computational tools like this could help us find those candidates sooner and even suggest how existing antibodies might be adapted as viruses change over time." 

Looking Ahead 

The findings suggest that biologically informed AI may offer a more effective path for antibody discovery. Beyond this study, the researchers believe biologically informed AI could ultimately transform therapeutic antibody development by helping scientists better understand antibody-antigen recognition, prioritize candidates for laboratory testing, and design more effective therapies. 

"Understanding how antibodies recognize their targets is fundamental to developing better antibody therapies, diagnostic tests, and vaccines," says Joseph-McCarthy. "By teaching AI the biology that matters most, we hope to give researchers better tools to discover, optimize, and ultimately design the next generation of antibody therapies." 

  

Pipeline for predicting antibody–antigen binding affinity. A protein language model encodes the antibody sequence, and a downstream model uses this representation to predict binding affinity to the target antigen.


Antibody structure 

The Y-shaped antibody contains heavy (VH) and light (VL) chains that form an antigen-binding site, including six complementarity-determining regions (CDRs) that recognize and bind the antigen.

Credit

Diane Joseph-McCarthy/Boston University



Physics-guided AI designs low-noise amplifiers that use 62% less power than expert designs




ELSP

Physics-guided, validity-gated multi-objective Bayesian optimization for CMOS LNA design. The method improves valid simulation yield from 47.5% to 95.7% and achieves 62% lower power and 10.7 dB better linearity than manual design within 190 simulations. 

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Physics-guided, validity-gated multi-objective Bayesian optimization for CMOS LNA design. The method improves valid simulation yield from 47.5% to 95.7% and achieves 62% lower power and 10.7 dB better linearity than manual design within 190 simulations.

view more 

Credit: Jithish Jayarajan/Singapore University of Technology and Design; Kiat Seng Yeo/Singapore University of Technology and Design, Tianjin University; Shuoyu Ji, Bharatha Kumar Thangarasu, Nagarajan Mahalingam/Tianjin University; Baoji Miao/Henan University of Technology






A physics-guided AI framework automatically optimizes 2.4 GHz CMOS low-noise amplifiers, reducing power consumption by 62% and improving linearity by 10.7 dB compared with an expert-designed baseline, while nearly doubling the rate of successful circuit simulations under foundry design constraints.

Every smartphone, Wi-Fi router and wearable device relies on a tiny circuit called a low-noise amplifier (LNA) to extract faint radio signals out of the air without drowning them in noise. Designing one is a delicate balancing act: power consumption, noise and signal fidelity pull against each other, and a skilled engineer typically spends days of iterative simulation and hand-tuning to get it right.

Automating that job has proven surprisingly hard for artificial intelligence. Chip designs must obey the strict rules of a foundry's process design kit (PDK). For example, on-chip inductors can only be chosen from a fixed library of pre-characterized components and most randomly generated candidate circuits simply fail. In the team's preliminary experiments, more than half of the simulated designs were invalid, violating transistor operating regions or impedance-matching requirements before the optimization could even get started.

Researchers from the Singapore University of Technology and Design, Tianjin University and Henan University of Technology now report a way around this bottleneck: teach the algorithm some physics before letting it search. Much like handing a student the textbook before the exam, their framework first uses simple resonance and impedance-matching relationships to generate “warm-start” designs that are physically sensible and buildable from the foundry's component library. A validity gate then screens every simulated candidate, so that only physically meaningful results are used to train the artificial intelligence (AI) model that steers optimization toward the best power–noise–linearity trade-offs.

The payoff is striking. Optimizing a 2.4 GHz LNA in a commercial 40 nm CMOS process with a budget of just 190 circuit simulations, roughly 16–19 hours of computing, versus days of manual iteration. The framework cut power consumption from 14.1 mW to 5.4 mW, a 62% reduction, while improving linearity (IIP3) by 10.7 dB compared with a handcrafted expert design, at the cost of a modest 0.21 dB noise-figure penalty. The share of valid simulations jumped from 47.5% during unguided sampling to 95.7% under guided optimization, roughly twice the rate achieved by popular open-source optimizers under the same budget.

To show the recipe is not a one-off, the team applied the identical pipeline to a structurally different amplifier. Without retuning the algorithm, it again outperformed the expert baseline, reducing power by 25%, lowering the noise figure by 0.36 dB and improving linearity by 2.59 dB.

The authors note that the study is a schematic-level proof of concept; future work will extend the framework to layout-extracted designs, process–voltage–temperature corners and other RF blocks such as power amplifiers, mixers and oscillators. Ultimately, the approach points toward practical, physics-aware AI design assistants for the analog circuits that connect our devices to the world.

This paper “Physics-guided multi-objective Bayesian optimization for process-aware CMOS LNA design” was published in Interdiscipline.
Jayarajan J, Ji S, Thangarasu B, Mahalingam N, Miao B, et al. Physics-guided multi-objective Bayesian optimization for process-aware CMOS LNA design. Interdiscipline 2026(1):0002, https://doi.org/10.55092/interdiscipline20260002.