Machine Learning · Cross-listed from stat.ML
Distillation of Synthetic Data for Time Series Foundation Models
Niloy Biswas and Noureddine El Karoui
Time series foundation models (TSFMs) are increasingly pre-trained on synthetically generated time series trajectories, where the data generating process is known. Current pre-training recipes are based on loss objectives which compare TSFM outputs to realized future values of each trajectory. We instead propose loss objectives which compare TSFM outputs to the conditional forecast distribution of each trajectory, a procedure we call synthetic data
distillation (SDD). SDD corresponds to a Rao-Blackwellization of the training objective, in that it leaves the expectation of
stochastic gradients unchanged while provably reducing the covariance of the
stochastic gradient under the Loewner partial ordering. We empirically validate SDD on a TSFM model family of sizes from $4$M to $2.5$B parameters, and observe faster convergence of validation loss at every model size: on Gaussian Process data, SDD attains or improves upon the Status Quo loss whilst requiring $10\%-40\%$ less training iterations.
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Information Theory
Characterizing Multi-Cell Pinching-Antenna Transmission: Revealing the Other Side of the Coin
Zhiguo Ding
Using pinching
antennas to enhance a user's connection to its own base station (BS) is intuitive and has been well investigated in the literature. This letter focuses on a less intuitive advantage of pinching
antennas from the interference-suppression perspective. In particular, using pinching
antennas ensures that all BSs serve their users with low transmit power, i.e., BSs can “whisper", rather than “shout", to their users. As a result, by experiencing less interference, a user's data rate can still be improved with pinching
antennas, even if its link quality to its own BS remains unchanged. A
stochastic geometric study is carried out in the letter, where BSs employ fractional power control. Analytical and numerical results are presented to reveal the significant impact of this interference-suppression capability offered by pinching
antennas.
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Cryptography and Security · Cross-listed from quant-ph
ECDSA.Fail: Open Autoresearch for Optimizing Elliptic-Curve Point Addition in Shor's Algorithm
Jieyi Long, Theodore Pender, Zhao Huang et al. (+32 more)
We propose Open Autoresearch, a paradigm in which humans and AI
agents publish evaluator-verified improvements to a public leaderboard. We instantiate it in ECDSA.Fail, optimizing reversible secp256k1 point-addition
circuits, a bottleneck in Shor's
algorithm for
elliptic-curve cryptography. The
benchmark minimizes the spacetime-inspired score $S=Q\times T$, where $Q$ is peak logical
qubit width and $T$ is average executed Toffoli count. Participants reduced $S$ by 86.1%. At the data cutoff (26 July 2026), the best-scoring
circuit uses 1,151
qubits and 1,299,453 average executed Toffoli gates, giving $Q\times T\approx1.496$ billion. This is more than 50% below Google's published point-addition score thresholds (arXiv:2603.28846), under different accounting conventions. Because the
benchmark supplies one addend classically, we construct a coherent windowed-addition-compatible variant implementing the single-call interface required by windowed Shor. It uses 1,162
qubits and 1,684,161 average executed Toffoli gates. On 100,000 random inputs, its empirical success probability is $\hat{p}=0.99809$, giving $Q\times T/\hat{p}\approx1.961$ billion under an independently rerunnable per-call sensitivity model, not a full-Shor success estimate. Its
qubit and Toffoli counts lie below Google's published thresholds and Schrottenloher's reported operating points (arXiv:2606.02235), although differing interfaces, accounting conventions, and validation scope preclude formal dominance. After the cutoff, the score was further reduced to 1.259 billion, while a separate low-width
circuit reached 813
qubits. The public record shows AI
agents complementing human judgment, providing evidence for open autoresearch on efficiently evaluable, machine-checkable objectives.
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All authors Jieyi Long, Theodore Pender, Zhao Huang, Manuel B. Santos, Samrendra Kumar Singh, Bartosz Naskręcki, Bit Wonka, Pierre-Luc Dallaire-Demers, Francesco Giannicola, Ruben M. L. Paschoarelli, Oli Freuler, Jackie Chia-Hsun Lee, Vasily Gnuchev, Gopi Kannappan, John Boyer, Xavier Butler, Akash Balasubramani, Jordan Newman, Bereket Dereje, Alexander Hertlein, Robert Kodra, Lucas Levy, Shaan Patel, JT Rose, Matt Zweil, Okechukwu Wisdom, Tarek El-Eter, Edison Lee, Michael Dong, Alan Li, Anto Joseph, Gajesh Naik, Gautham Anant, Soubhik Deb, Justin Drake
Networking
Automated Mobile Video Objective Testing System
Eric Petajan, Jonathan Lynam, Morey Antebi et al. (+5 more)
Applying QoE analysis to optimize usage of cellular spectrum is of high interest to mobile network operators. A key challenge is to be able to perform QoE measurement across very different types of apps, from DASH VoD to interactive applications such as
Video Conferencing and Cloud Gaming. This paper presents AMVOTS, a QoE measurement system developed by AT&T, which is flexible enough to support a large range of application types and network conditions. We also discuss using AMVOTS as part of a closed loop to prototype QoE-aware
radio resource allocation.
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All authors Eric Petajan, Jonathan Lynam, Morey Antebi, Hessam Moeini, David Lindero, Lars Ernstrom, Gyanesh Patra, Szilveszter Nadas
Artificial Intelligence
CityPlanner: A Sandbox Agent for Executable Urban Planning
Wentao Zhang, Jingyuan Wang, Zetong Zhou et al. (+2 more)
Urban planning is a real-world spatial optimization problem that requires selecting feasible actions from large candidate spaces under practical objectives such as cost and service quality. Existing optimization and reinforcement learning methods are effective for fixed formulations, but often depend on task-specific representations and constraint handling. We propose CityPlanner, a sandbox-
agent framework for executable urban planning. CityPlanner introduces UrbanSandbox, a unified file-based environment where
agents inspect task files, generate plans, run evaluators, and revise decisions based on executable feedback. To make learning tractable, we further propose atomic-task reinforcement learning, which decomposes long sandbox trajectories into BuildPlan for initial construction and ImprovePlan for feedback-based refinement. Experiments on a real-world
benchmark show that CityPlanner consistently outperforms heuristic, task-specific RL, and general LLM-
agent baselines. Ablations verify the contributions of UrbanSandbox, atomic-task RL, and iterative deployment. We release the code and
dataset at https://anonymous.4open.science/r/co-
agent-C1C8
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All authors Wentao Zhang, Jingyuan Wang, Zetong Zhou, Yifan Yang, Wenrui Wang
Artificial Intelligence · Cross-listed from eess.IV
Myocardial Strain Drift Correction in Deep Learning Based Ultrasound Tracking
Thierry Judge, Nicolas Duchateau, Andreas Østvik et al. (+6 more)
Myocardial strain from echocardiography is a key biomarker for cardiac function. Recent deep learning methods show strong performance for myocardial motion tracking but often lack physiological constraints, leading to temporal drift across the cardiac cycle. Consequently, tracked points may not return to their relative initial positions at the end of each cardiac cycle, producing inaccurate strain estimates and even divergence in some cases. We propose a deep learning framework that compensates for drift during myocardial tracking. We extend a state-of-the-art echocardiographic tracking method (TAS-Net) with persistent
memory tokens that share information across sliding windows over full cardiac cycles. A teacher-student fine-tuning strategy on real echocardiographic data then enforces physiologically consistent cyclic motion while preserving tracking accuracy. Experiments show reduced global and regional strain drift, improved agreement with clinical references, and better test-retest reproducibility, supporting more reliable myocardial strain estimation in clinical practice.
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All authors Thierry Judge, Nicolas Duchateau, Andreas Østvik, Havard Dalen, Bjørnar Grenne, Pierre-Yves Courand, Lasse Lovstakken, Pierre-Marc Jodoin, Olivier Bernard
Computation and Language
Beyond Top Words: MonoTM for Topic Modeling with Interpretable Monosemantic Features
Una Joh and Bei Yu
Topic models summarize large text corpora, but top-ranked words often provide only a limited representation of topic semantics. Sparse autoencoders (SAEs) offer a way to move beyond word-level descriptors by extracting interpretable features from dense representations, yet how feature interpretability relates to topic-inference quality remains unclear. We introduce MonoTM, an interpretable topic modeling framework that decouples these roles. Across three
benchmark corpora, we show that document–topic mixture estimation and semantic interpretation favor different SAE configurations and feature subsets. MonoTM estimates mixtures from the full SAE bag-of-features representation and, with them fixed, learns topic descriptors over a separate vocabulary of corpus-grounded semantic features. This design preserves global topic structure while representing topics with semantic units more meaningful than individual words, making them more useful for downstream corpus analysis.
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Cryptography and Security
When Ad Networks Misbehave: Understanding Risks of Semi-Drive-By Splash Ads
Song Wu, Bo Wang, Yifan Zhang et al. (+2 more)
We investigate the mobile splash ads ecosystem, i.e., full-screen advertisements shown at app launch, where monetization relies on interaction signals that are difficult to verify end-to-end. This setting is especially sensitive because incidental touches and sensor-driven callbacks are common yet easy to misattribute as engagement. Prior work has largely framed mobile ad fraud as a publisher-side problem, while some studies attribute fraudulent operations to embedded ad libraries. Yet an important risk remains underexplored: ad SDKs control how interaction signals are interpreted, measured, and reported, creating an opportunity to reinterpret ambiguous user or device signals as valid advertising interactions. We uncover a previously less-known form of fraud at the ad-network layer in which splash ads are triggered not by intentional user actions but by incidental or indirect interactions, which we term semi-drive-by splash ads. By translating non-ad interactions into billable engagement events, ad networks can inflate performance metrics, overcharge advertisers, and erode user trust. To expose this behavior in the wild, we design AdHive, an automated honeypot-like analysis framework that induces evasive splash-ad delivery and landing behaviors under realistic device conditions. AdHive reproduces human-like activity through LLM-generated usage traces and sensor dynamics, enabling execution paths that remain hidden in conventional analysis environments. Our large-scale measurement across thousands of popular Android applications shows that semi-drive-by splash ads are widespread and are often triggered by subtle signals such as minor sensor variations. We further confirm real-world impact by working with one of China's largest advertisers, identifying multiple ad networks engaging in this fraud and leading to enforced repayments of about 4 million Yuan (approximately US$600,000).
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All authors Song Wu, Bo Wang, Yifan Zhang, Yinfeng Cao, Xueqiang Wang
Computational Engineering
Geometric organization of olfactory descriptor data in the Poincaré disk
Aniss Aiman Medbouhi, Farzaneh Taleb, Giovanni Luca Marchetti et al. (+1 more)
Odor quality is commonly represented using high dimensional descriptor profiles, yet their low dimensional organization remains unclear. We investigated whether a two-dimensional
hyperbolic embedding can provide an interpretable representation of this structure. We applied
hyperbolic metric multidimensional scaling to two complementary
datasets: 480 Sagar rating profiles from three participants rating 160 odorants on 15 continuous descriptors, and 4983 GoodScents–Leffingwell molecules annotated with 138 binary descriptors. The
embeddings substantially preserved pairwise descriptor distances, supporting subsequent analyses of radial and angular organization. In Sagar, rating profile
entropy was strongly and negatively associated with
hyperbolic radius, with diffuse profiles closer to the center and concentrated profiles closer to the boundary. This radial organization emerged primarily at the level of the full descriptor profile, rather than any individual descriptor, and remained robust across alternative descriptor representations, participant specific analyses, and averaged ratings. Sweet, musky, fruity, pleasantness showed the strongest directional trends. In GoodScents–Leffingwell, active label
entropy, reflecting descriptor multiplicity, increased with radius, whereas orthogonalized descriptor
entropy, reflecting spread across orthogonal modes, decreased with radius. Related binary descriptors occupied coherent localized high-density regions. These findings reveal complementary radial and angular organization in the
hyperbolic representation of olfactory descriptor data. They support
hyperbolic mapping as an interpretable descriptive framework in which radius summarizes global profile properties, while the angular component captures continuous descriptor gradients and categorical organization.
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All authors Aniss Aiman Medbouhi, Farzaneh Taleb, Giovanni Luca Marchetti, Danica Kragic
Artificial Intelligence · Cross-listed from stat.ML
Learning with Synthetic Data via SGD in High-Dimensional Linear Regression
Jichu li and Difan Zou
Synthetic data has become a promising way to scale model training beyond limited human-generated data but it may also induce strong model collapse (Dohmatob et al., 2024), where any fixed fraction of synthetic data prevents model performance from improving under data scaling, leaving a non-vanishing excess risk floor. In this paper, we study how synthetic data affects the generalization of one-pass SGD in high-dimensional linear regression with model shift. We establish finite-sample risk bounds for mixed and two-stage training, separating standard bias and variance from source-mismatch effects, namely fluctuation and persistent drift under mixing and filtered initialization bias under two-stage. These bounds reveal a sharp contrast: mixed training induces strong model collapse, while two-stage training avoids the floor by using synthetic data only in the first stage, showing that collapse is not inevitable under a simple data curriculum. Under a random sketch model, we further obtain scaling laws for both protocols, with tight results for mixed training in the optimization-saturated regime. These laws show that larger models may amplify synthetic-induced degradation under mixing, and quantify how high-quality synthetic pretraining may reduce bias in two-stage training. Finally, we establish an exact finite-sample necessary-and-sufficient condition for two-stage training to strictly outperform real-only training under the same real-data budget and identical real-stage updates. Overall, our results highlight that synthetic data is neither inherently harmful nor beneficial; its effect depends critically on both its quality and the training protocol used to incorporate it.
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Computation and Language
Reproducing Omitted Temporal Expressions in Japanese News for Retrieval-Augmented Applications
Tomoaki Yasuda and Shotaro Ishihara
News articles often contain omitted temporal expressions, such as day-only or month-only mentions, which must be interpreted with reference to the publication date. When such articles are indexed or processed as standalone text in search and
retrieval-augmented generation (RAG) systems, these omissions can cause temporal mismatches and unstable interpretation by large
language models. We focus on reproducing omitted temporal expressions as concrete dates or intervals using the publication date as external context before the articles are indexed for search and RAG applications. Specifically, building on established temporal-expression extraction and normalization techniques and informed by a manual analysis of Japanese news articles, we propose jaROTE, a rule-based pipeline for Japanese news. Experiments on two news corpora demonstrate that jaROTE achieves high performance, and remains competitive with LLMs while providing a fast, low-cost pipeline. We further show that temporal reproduction improves time-constrained lexical
retrieval, demonstrating the practical value of publication-date-grounded normalization for Japanese news
retrieval.
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Machine Learning
Positional task conditioning for scalable defect detection across product families in large product catalogs
Soham Satyadharma, Gabriel Roccabruna and Suleiman A. Khan
Product families in large product catalogs suffer from inconsistencies such as duplicates and unit mismatches that degrade customer experience. Detecting these requires
reasoning over multiple error types across lengthy product listings, where LLM classification quality degrades due to long-context limitations. We address this by decomposing detection into focused sub-tasks that reduce context and isolate error types, improving F1 from 52% to 87%. For scalable deployment, we introduce Positional Task Conditioning (PTC), which distills this capability into a single smaller model by reinforcing task identity at structural
prompt boundaries. PTC outperforms rationale-based
distillation across five models and two architecture families, achieving within 1.79% F1 of the frontier at upto 98% lower cost. Our system is deployed across multiple countries processing 10+ million product families.
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Artificial Intelligence
Multi-Agent Agentic Graph Learning via Structural Signatures
Liang Qu, Jianxin Li and Hua Wang
Agentic graph learning (AGL) has recently achieved promising results on graph
reasoning tasks, where an
agent powered by a large
language model (LLM) sequentially samples the graph as evidence to support its final prediction. Existing methods either employ a single
agent or orchestrate multiple role-based
agents to reason and learn over the entire graph, but both essentially rely on a shared
reasoning policy across different graph regions, which can be suboptimal for graphs with heterogeneous structural and semantic patterns. Inspired by the progress of multi-
agent collaboration on complex
reasoning tasks, a natural remedy is to let multiple
agents own different
memory and collaborate; however, applying this paradigm to graphs directly faces two challenges. First, existing AGL methods typically verbalize graph structures into natural-
language descriptions for LLM
agents, making the
reasoning process sensitive to the ordering of structural information and thereby breaking the permutation-invariant nature of graphs. Second, incorporating increasingly large sampled neighborhoods leads to rapidly growing contexts. To address these challenges, this paper introduces a multi-
agent agentic graph learning (i.e., MAAGL) framework. MAAGL partitions the graph into communities and assigns an independent
agent to each community for region-specific specialization. MAAGL represents structural and semantic evidence separately. Structural evidence is summarized by a dynamically updated structural signature that is permutation-invariant and fixed in size, while semantic evidence is filtered to the top-k nodes ranked by relevance. Based on historical trajectories with similar signatures,
agents estimate their confidence and trigger debate-style collaboration when needed. Extensive experiments on four
benchmark datasets show that MAAGL outperforms SOTA AGL methods.
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Machine Learning
Robust Industrial Cyber Physical Classification Using Neuromorphic Temporal Embeddings and Hybrid SNN XGBoost Under Machine Unlearning Attacks
Ammar Kamoona, Sajad Koushkbaghi, Mahdi Jalili et al. (+2 more)
The digitalisation of electrical distribution networks has increased the exposure of power-grid infrastructure to cyber attacks. Existing intrusion detection systems (IDSs), however, often rely on computationally expensive deep learning models that are difficult to deploy at the edge. Periodic retraining also exposes these systems to machine unlearning attacks, where selective data removal can degrade detection performance. We propose a hybrid Spiking Neural Network (SNN) and XGBoost architecture that combines efficient temporal encoding with a lightweight classifier and provides structural resilience to such attacks. The SNN is trained once on clean data and used as a fixed feature extractor, while only the XGBoost classifier is retrained during model updates. Evaluated on two real-world public power-system
datasets, the proposed method achieves 99.9% accuracy (F1-macro 0.999) on the Synchrophasor
dataset and 95.0% accuracy (F1-macro 0.943) on the MSU/ORNL
dataset, outperforming standalone baselines. Under selective label-flipping attacks, the hybrid model loses only 0.9% F1-macro at 10% poisoning and delays target-class collapse from 60% to 70% poisoning compared with raw models. These results demonstrate that neuromorphic temporal encoding can provide both accurate cyber-attack detection and improved resilience to data poisoning in cyber-physical systems.
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All authors Ammar Kamoona, Sajad Koushkbaghi, Mahdi Jalili, Peter McTaggart, Xinghuo Yu
Computation and Language
Towards Automatic Evolution Tree Generation from Citation Graphs
Zexing Zhao, Yuntong Hu and Liang Zhao
Surveys remain the primary way researchers grasp the lineage of methods within an AI subfield, but they scale poorly against the current rate of publication. Existing taxonomy-induction methods are largely leaf-bound and time-agnostic; they tend to force transitional papers into mature leaves and can create topological inversions between ancestors and descendants. We propose EvoTree, a staged framework that decouples conceptual backbone learning from temporal refinement: a graph-aware encoder with distribution-based hierarchical clustering yields a stable taxonomy backbone; temporal fine-tuning then re-attaches marginal papers to internal nodes under monotonic-path constraints; a final LLM pass labels concepts without altering the
topology. We release the first annotated
benchmark for this task across 11 AI subfields. EvoTree attains the highest NMI and citation-direction accuracy among all baselines and the best concept purity on the annotated
benchmark, and is the only method with non-trivial marginal-paper detection on the annotated set.
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Software Engineering
The Vibe Shift in Software Engineering: Evaluating AI-Led Conversational Programming for Performance, Cognition, and Responsible Adoption
Sales G. Aribe Jr. and Louie Jay S. Labastida
This study evaluates Vibe Coding, an emerging AI-led conversational programming paradigm that enables developers to generate software through natural-
language interaction with large
language models. Using a mixed-methods design, the study assessed performance efficiency, cognitive implications, and responsible adoption in comparison with traditional and AI-assisted coding environments. Thirty participants, including professional developers and advanced computing students, completed equivalent programming tasks under three experimental conditions. Quantitative data were analyzed using descriptive statistics and repeated-measures ANOVA, while qualitative data were examined through thematic analysis. Results show that vibe coding significantly improved development efficiency, reducing task completion time by 27% compared with traditional coding and 12% compared with AI-assisted coding. However, these gains were accompanied by lower maintainability indices and higher security vulnerabilities, indicating trade-offs in software quality. Usability results yielded a good rating (SUS = 71.4), while cognitive workload remained moderate (NASA-TLX = 55.5), reflecting reduced syntactic effort but increased linguistic
reasoning. Thematic analysis identified trust calibration, loss of control, cognitive adaptation, and
prompt-engineering strategy as key constructs. Notably, perceived loss of control was associated with increased security risks due to reduced transparency and validation of AI-generated outputs. Based on these findings, the study proposes a three-pillar framework for responsible adoption: hybrid integration of human and AI capabilities, human oversight and transparent accountability, and context-aware deployment. Overall, vibe coding enhances productivity but requires critical oversight, reinforcing its role as a transformative yet transitional paradigm in software development.
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Hardware Architecture
Differential Stochastic Simulated Annealing Processor for Fully Connected 2048-Spin Optimization
Naoya Onizawa, Md Mohaimenul Alam, Sean Smithson et al. (+2 more)
A 2,048-
spin fully connected annealing processor based on differential
stochastic simulated annealing (DSSA) is presented as an architectural design in TSMC 28 nm CMOS with a 3 mm x 4 mm post-layout area. The processor closes timing at 500 MHz, integrates a 16 Mb SRAM weight
memory, and amortizes
stochastic noise across 16
spins with area-efficient random number generators. DSSA keeps a serialized datapath for density but recomputes interactions only for
spins that flip, shrinking the effective workload to the active frontier during each annealing run.
Spin-select scheduling, priority-based weight reads, and a temperature controller that skips idle steps accelerate sparse updates without sacrificing full connectivity. Post-layout simulation results show 2.7 ms time-to-solution (TTS) and 0.86 mJ energy-to- solution on 2,000-
spin problems at 316 mW (0.15 mW/
spin), achieving 1.5x lower power and 3.5x lower TTS energy than projected prior fully connected annealers. These results demonstrate the potential of the proposed DSSA architecture for large-scale combinatorial optimization hardware under post-layout evaluation.
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All authors Naoya Onizawa, Md Mohaimenul Alam, Sean Smithson, Duckgyu Shin, Takahiro Hanyu
Artificial Intelligence · Cross-listed from stat.ML
High-probability guarantees for linear accessibility in feature superposition
Enrico Vompa
Neural networks can leverage feature superposition to encode more concepts than dimensions, but cross-feature interference constrains the linear accessibility of simultaneously active features. By framing linear accessibility as a compressed sensing problem, we derive high-probability bounds for fixed supports under subgaussian noise, proving the sufficient dimension scales linearly ($d=O_{\varepsilon}(k \log m)$) rather than prior worst-case quadratic limits. We characterize the asymmetry between active and inactive interference and the trade-off between interference and observation-noise budgets. We then validate these bounds across system parameters through Gaussian-tail approximations. We also introduce IHT-SAE, which uses learned iterative refinement to improve feature recovery beyond the limits of linear availability. These results quantify the
geometric constraints of the linear representation hypothesis, providing a framework for evaluating sparse autoencoders, compositional generalization, and neural interpretability.
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Computation and Language
BuzzASR: A Swarm of 100+ Monolingual Speech Recognition Models
Shivam Singh, Aditya Yadavalli, Catherine Arnett et al. (+1 more)
We introduce BuzzASR, a collection of
language-specialized fine-tuned Whisper models adapted for automatic
speech recognition (ASR) in 102
languages. Large end-to-end
Transformer-based ASR models such as Whisper have revolutionized ASR, but most prominent models are highly
multilingual. As a result, these models often perform poorly on
languages less well-represented in their training set. While it has long been known that effective
language adaptation can be achieved through simple fine-tuning on monolingual data, this strategy has only been applied to a small number of
languages. We massively scale up this simple approach to 102
languages covered in the FLEURS
dataset, while also implementing a more complex
language adaptation strategy that integrates monolingual tokenizer replacement and data augmentation using text-only fine-tuning. BuzzASR models outperform Whisper-large-v3 on 77 out of 102
languages, reducing character error rates (CER) by a factor of over 2.8 on average. Our models achieve state-of-the-art CER among open-source systems on 27 of 102
languages on the combined FLEURS and Common Voice test set. Our tokenizer replacement strategy yields an average 3.3x improvement in compression rate (characters per
token) over Whisper's
multilingual BPE, with gains of up to 21.7x. We release all models, code, and detailed results: https://lemn-lab.github.io/buzz-asr
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All authors Shivam Singh, Aditya Yadavalli, Catherine Arnett, Alex Warstadt
Cryptography and Security
Arbitrary Cipher Attacks Against Large Language Models Do Not Require Fine-Tuning
Thomas Rivasseau
Large
language model safety and security research is preoccupied with, among other things, detecting and preventing jailbreak attacks:
alignment bypasses that allow an
adversarial user to elicit unwanted or harmful outputs from models. Arbitrary cipher, or covert communication, attacks are one such type of jailbreak and have previously been demonstrated against the fine-tuning APIs of commercial models. In these attacks, target models are trained on a corpus of encrypted harmful questions and responses and subsequently respond to harmful requests through the learned encryption scheme. In this paper, we show that newer frontier models do not require fine-tuning to acquire cipher-based communication skills. Instead, they can learn these skills through prompting and, when necessary, through in-context learning. Furthermore, model
alignment is significantly weakened or entirely bypassed when communication occurs through the learned cipher. To the best of our knowledge, this constitutes a novel attack vector against commercial black-box large
language models. We demonstrate successful jailbreaks against frontier models developed by Anthropic, Google, and OpenAI. Our attack bypasses commercial harmfulness classifiers because harmful content is encrypted and therefore appears as nonsensical text or gibberish.
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Computation and Language
TEFM: Token-Efficient Faithful Modeling for Structured Data
Zhichao Hou, Lingdao Sha, Xueyu Mao et al. (+3 more)
In this paper, we solve two fundamental obstacles in applying LLMs to critical domains:
token efficiency and faithfulness. To address both constraints jointly, we present TEFM (
Token-Efficient Faithful Modeling), a framework designed for structured data analysis in critical domains. TEFM achieves
token efficiency by compressing lengthy structured observations into compact Behavioral Code
tokens, dramatically reducing
token consumption with minimal information loss. Moreover, TEFM enables faithful rationalization through a dual-fidelity objective that jointly optimizes code-level reconstruction and prediction-level fidelity, identifying minimal sufficient feature subsets grounded in input data. Comprehensive experiments across various domain
datasets and model backbones (Qwen3, Gemma-2, Phi-4) show that TEFM achieves competitive classification accuracy with dramatic
token reduction (approximately 1%
token retention in clinical and 2% in security domains) while producing faithful rationales.
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All authors Zhichao Hou, Lingdao Sha, Xueyu Mao, Yang Liu, Peijie Qiu, Rui Song
Cryptography and Security
An Efficient and Effective Agentic Group Shilling Attack on Recommender Systems
Quoc Viet Nguyen, Trinh Pham, Viet Huynh et al. (+4 more)
Recommender systems have become core infrastructure for modern online platforms, personalizing content at scale and strongly influencing what users see, click on, and purchase. However, this dependence on user interaction also exposes them to shilling attacks, where malicious actors can inject fake profiles to distort item rankings and control visibility. Existing attacks often rely on target-specific fine-tuning or fixed profile templates, making them either difficult to adapt to different victims or easier to detect. To overcome these limitations, we propose the Agentic Group Attack System (AGAS), a coordinated shilling framework where a central Coordinator directs a group of role-switching worker
agents to adaptively promote a target item across different victim families. The Coordinator dynamically adjusts the strategy when progress stalls or suppression signals increase, while workers pursue a shared objective and switch between active and inactive roles to avoid repetitive patterns. Under the same attack budgets and evaluation protocols, AGAS consistently surpasses strong baselines in target promotion while better preserving benign recommendation quality, weakening representative detectors, and achieving higher efficiency than prior attacks. These findings also emphasize that defending recommender systems may require mechanisms that can handle adaptive shilling campaigns, not just isolated fake-profile injections. Our code is available at https://github.com/phkhanhtrinh23/AGAS.
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All authors Quoc Viet Nguyen, Trinh Pham, Viet Huynh, Hongzhi Yin, Quoc Viet Hung Nguyen, Bay Vo, Thanh Tam Nguyen
Computational Geometry
The Hyperbolic Surface Distance, Diameter, and Dirichlet Problems
Vincent Despre, Auguste Gezalyan and Marc Pouget
Despite the prominence of
hyperbolic surfaces in mathematics, basic algorithmic questions about them, even computing the distance between two points, have remained open, leaving many features of these surfaces inaccessible. The classical machinery assumes a polyhedral structure absent on a smooth surface. We remove these obstacles. We begin with an efficient $O(g^2)$
algorithm for the distance between two points, where $g$ is the genus of the surface. Building on it, we obtain an $O(g^2 \log g)$ method for answering distance queries from a fixed source and, as a consequence, for recentering a Dirichlet domain around an arbitrary point. This understanding of distances on the surface then lets us approximate the diameter to within any $\eps$ in time $O(g^3 \log g / \eps^2)$. We further show that the diameter, a single real number encoding a great deal about the surface, is exactly computable. Its
hyperbolic cosine is an algebraic number over the field encoding the coefficients of the
hyperbolic isometries defining the surface.
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Machine Learning
A Statistical Approach to Estimating Sample Size of Machine Learning Models
Dat Phan-Trong, Sunil Gupta and Svetha Venkatesh
Sample size determination for machine learning (ML) prediction models is challenging because conventional power analysis typically requires the predictor-outcome relationship and effect structure to be specified a priori. Nonlinear ML models learn complex prediction surfaces that do not admit straightforward analytical power calculations. We propose a framework that approximates nonlinear ML models with localized linear representations and estimates sample size requirements by evaluating statistical power across these local regions.
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Numerical Analysis
A Convergent Reaction-Drift-Diffusion Master Equation with Interaction Potentials
Max Heldman and Samuel A. Isaacson
We extend the convergent reaction-
diffusion master equation (CRDME) framework on unstructured grids to include two-body interaction potentials between particles. Such interactions are essential for modeling systems in which particles experience electrostatic repulsion, volume exclusion, or van der Waals attraction. Our approach discretizes the weak form of the forward equation for a particle-based
stochastic reaction- drift-
diffusion model to obtain a new CRDME by combining two complementary techniques: an edge- averaged finite element method with mass-lumping quadrature for spatial transport terms that include potential interactions, and a mix of finite volume and mass-lumping quadrature approximations for reaction terms. This yields transition rates for a spatial jump process of particles hopping between dual mesh voxels and undergoing reactions. The resulting spatially discrete CRDME retains key physical properties of the continuum system in closed domains. It preserves the Gibbs-Boltzmann
equilibrium distribution in the absence of reactions, and satisfies detailed balance of both drift-
diffusion and reactive fluxes for systems with reversible reactions. Numerical comparisons with Brownian dynamics simulations validate our method, and we demonstrate empirical second-order convergence as the mesh is refined.
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