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When Linear RUL Labels Disagree with Vibration Degradation: A Stage-Aware Target and Dual-Scale Predictor Evaluated on XJTU-SY and IMS

Why bearing failure timelines don't match what vibration sensors actually show

Machines fail in predictable stages—but the standard way of labeling remaining lifespan (as a straight line over time) doesn't match what vibration sensors actually measure. Researchers built a new prediction system that accounts for three distinct failure phases, fitting a curve that bends to match real vibration behavior. On test bearings, this stage-aware approach cut prediction error by 10–15% compared to the traditional linear method.

Industrial bearing failures cause unplanned downtime and expensive repairs. Better predictions of when a bearing will actually fail—rather than guesses based on calendar time—let maintenance teams act at the right moment: not so early that they waste money on premature replacement, not so late that the machine breaks down. This method shows that off-the-shelf sensors can be more useful if the software interpreting them accounts for how machines truly degrade.

Lifting Lifted Product Codes

Building better quantum error-correcting codes by expanding their mathematical structure

Physicists have developed a systematic method to create larger and more efficient quantum error-correcting codes by mathematically "lifting" existing ones while keeping their core structure intact. The approach yields codes with better performance than previously available versions and makes it cheaper in terms of physical resources to perform reliable quantum operations on these codes.

Quantum computers need error correction to function reliably, and the overhead required—extra qubits and operations needed to protect against mistakes—is a major barrier to building practical machines. This work produces codes that require less overhead while maintaining error protection, directly reducing the resource demands of near-term quantum computers. The systematic construction framework also opens a path toward understanding whether quantum error correction can scale efficiently without relying on physical space and geometry, a theoretical question that matters for long-term quantum computing architecture.

Algorithms for Structured Elections under Thiele Voting Rules

Making it faster to count votes when approval patterns follow a simple structure

Researchers found that a common voting method becomes much faster to compute when voters' approval choices follow a specific structure—where each candidate is approved by voters in a consecutive block. The team designed new algorithms that can solve what would otherwise be computationally intractable problems, and also cracked two long-standing open questions about how to quickly count votes under approval-based rules.

As organizations and governments adopt approval voting for committee selection, the ability to actually compute winners becomes essential. These algorithms make it practical to run Proportional Approval Voting on real-world elections where the approval patterns naturally cluster—a common scenario in actual voting data. This bridges the gap between voting theory and implementation by proving that structured real-world elections don't have the computational barriers that have limited these fairer voting systems' adoption.

Secure Aggregation for Privacy-Preserving Federated Learning on Clinical EEG Data

Letting hospitals train AI together without exposing patient brain data

Researchers created a system that lets multiple hospitals train a shared machine-learning model on EEG brain scans without sending anyone's actual patient data to a central server. The method uses mathematical masking and secret-sharing to hide individual hospital updates even from the aggregation server, and works whether you trust that server or assume it might cheat.

Hospitals can now collaborate on better AI models for brain disorders while keeping sensitive neurological data private and on-site. The tradeoff is real—adding strong privacy protections slows things down and requires more computation—but the semi-honest version adds only modest overhead, making it practical for real healthcare networks.

Eventually greedy best Egyptian underapproximations of rational numbers via optimal control

A 75-year-old puzzle about breaking fractions into simpler pieces

Mathematicians have solved a problem posed by Erdős and Graham in the 1970s about ancient Egyptian fractions—a method of writing rational numbers as sums of unit fractions (fractions with numerator 1). The researchers proved that every positive rational number can be built using a 'greedy' approach that always picks the largest possible unit fraction at each step, whether or not you're allowed to repeat the same denominator.

Egyptian fractions aren't just historical curiosities—they appear in computer algorithms, cryptography, and number theory. This proof settles a foundational question about whether the simplest approximation method always works, which establishes new bounds on how large denominators can grow when repeatedly breaking down fractions. The work also introduces an optimal control framework that other researchers can now apply to similar problems in discrete mathematics.

Hierarchical Spatio-Temporal Transformer for Coherent Emergency Department Forecasting

Making emergency room forecasts that add up across hospitals, regions, and nations

A new AI system called HierSTT predicts patient demand at emergency departments across three interconnected levels—individual hospitals, regional networks, and entire countries—in a single model. Unlike existing forecasting tools that predict at only one level and often produce contradictory numbers, HierSTT ensures that hospital predictions logically add up to regional forecasts, which add up to national totals, while improving accuracy by 32% over current best methods.

Hospital administrators, regional planners, and health officials currently work with forecasts that don't align, making it impossible to staff and resource hospitals efficiently. HierSTT's coherent predictions mean hospitals get reliable staffing numbers while regional and national planners can trust that totals match up, reducing wasted resources and improving patient care during predictable demand surges. The researchers also released data from 81 Portuguese hospitals, giving other healthcare systems a foundation for building similar tools.

Breaking the Curse with BAND: Nonparametric Distribution Estimation in High Dimensions

Estimating probability patterns in high-dimensional data without exponential slowdowns

A new method called BAND uses sparse networks to estimate what patterns exist in complex, high-dimensional datasets—breaking through a long-standing mathematical barrier that makes traditional approaches exponentially slower as data dimensions increase. The approach works on mixed data types (numbers, categories, time series) and achieves estimation speeds that scale polynomially rather than exponentially with dimension.

Many real-world problems—genomics, climate modeling, financial forecasting—involve hundreds or thousands of variables, making traditional statistical methods impractical. BAND makes these high-dimensional estimation problems computationally feasible, enabling faster and more reliable probability forecasts in domains where previous methods would simply take too long to produce usable results.

A behavior-environment information loop drives sensory navigation

How animals use sensing and movement as a two-way feedback loop to find food

Organisms navigate by constantly looping information between what they sense and how they move — and these two directions of information flow predict how well they navigate. Researchers measured this two-way coupling in bacteria, worms, flies, and AI agents, finding that the same principle explains navigation success across all of them, even though each creature uses completely different strategies.

Understanding how organisms actually navigate could improve robot design, from search-and-rescue drones to autonomous vehicles that need to find targets in unfamiliar environments. The framework also reveals what makes each creature's strategy work — why a bacterium tumbles the way it does, or how a fruit fly learned to track smells — which could lead to better biological pest control or faster algorithms for AI agents learning to explore.

SciFigQual-Bench: A Benchmark for Scientific Figure Quality Assessment with Full-Manuscript Context

Teaching AI to judge whether scientific figures actually support their claims

Researchers created a benchmark of over 6,300 scientific figures from top computer-science papers, each scored by experts on five qualities: clarity, layout, how well captions match images, relevance to the text, and whether the figure misleads. They then built an AI system that learned to evaluate figures the same way humans do, achieving 93% consistency with expert judgment—significantly better than existing image-quality tools, which weren't designed for scientific content.

Scientific papers rely on figures to communicate results, but no automated system has existed to catch figures that are unclear, mislabeled, or misleading. This benchmark and AI tool could help journal editors and researchers spot problematic figures before publication, reducing the spread of poorly presented—or even deceptive—research findings.

Dead Reckoning: Counting Your Customers Who Never Say Goodbye

Why companies can't really know how many customers they still have

When customers stop buying without announcement, companies use statistical models to guess who's still active. But the paper shows these models are fundamentally unreliable: different reasonable assumptions produce customer counts that vary by a factor of 7.6 on the same dataset, even when predictions about near-term purchases match closely. The problem isn't bad math—it's that the models extrapolate infinitely far into the future, where verification is impossible.

Companies use these customer counts for valuation, marketing budgets, and strategic decisions worth millions of dollars. When the same data can justify counts ranging from 3,654 to 27,734 active customers, leadership is making bets on a number with almost no reliable foundation. The paper shows the honest fix: report concrete, verifiable predictions over a fixed time horizon (like "18-month repeat purchase rate") instead of an extrapolated infinity, and if a total count must be given, present it as a wide range rather than false precision.

Where does the criticality live? Early-warning signals are event-heterogeneous across seven crypto-perpetual liquidation cascades

Why crypto crash warnings work differently depending on what triggers them

A study of seven major Bitcoin liquidation crashes found no single early-warning signal that works across all events. Price showed telltale signs of instability before five crashes but completely failed to warn of two sudden news-driven collapses; only a compression in trading order-flow emerged as a consistent (though imperfect) precursor across all events. This suggests crypto crashes fall into at least two different types—those that build up gradually and those triggered suddenly by external shocks—each with its own fingerprint.

Regulators and traders looking for a universal early-warning system for crypto derivatives crashes won't find one. The October 2025 crash, which wiped out 19 billion dollars, defied the most commonly cited warning signal. Understanding that different crashes have different signatures means any real-world alarm system would need to watch multiple indicators simultaneously and adapt its logic based on market conditions—a harder engineering problem than existing proposals assume.

π\mathbf{R}^2: Reactive Real-time Flow Policies

Making robot control policies react fast enough to handle the unexpected

Current AI-powered robot controllers plan their moves in chunks and can't adjust mid-action, making them clumsy when things change unexpectedly. Researchers created πR², a new approach that lets robots react to what they sense right now while keeping powerful AI models and planning for multiple actions at once. On real robots, it replans about 4 times faster than existing methods and improves success rates by up to 30%.

Robots trained with large AI models are increasingly useful, but they've been slow to react to surprises—a dropped object, a shifting surface, an unexpected obstacle. πR² lets them adjust course in real-time without slowing down, using the same powerful models. This means robots could handle messier, less predictable real-world tasks like assembly lines or warehouse work where conditions constantly shift.