Machine Learning
Position: AI for Science Should Treat Measurement-to-Dataset Pipelines as Inference Components
Ling Zhan, Xiaoyao Yu and Tao Jia
AI for Science (AI4Science) workflows often treat the released
dataset as a fixed interface to the underlying system. However, in domains relying on indirect observation, the learner observes a derivative representation produced by multi-stage measurement, reconstruction, and preprocessing pipelines. We argue that these measurement-to-
dataset pipelines are inference components: treating their outputs as “given data” freezes an observation model and obscures uncertainty over feasible pipeline choices. We identify three failure modes arising from this “frozen lens”: (C1) hidden hypothesis space, where the released
dataset does not specify the pipeline configuration or its validity conditions; (C2) uncertified transportability, where a pipeline may be documented but its regime of validity is untested, so failures under distribution shift cannot be adjudicated; (C3) ungoverned multiplicity, where many defensible pipelines exist and dispersion is real but not propagated into uncertainty-aware evidence. We stress-test these claims with a large-scale neuroscience empirical audit, finding a survival rate of $\approx 0.0004\%$ under a cross-
dataset stability criterion. We call on the AI4Science community to make pipelines computable inference objects via domain-specific Computable Observation Frameworks. This shift enables quantifying pipeline adequacy and stability, converting implicit implementation choices into auditable, reproducible, and cumulative scientific evidence.
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Machine Learning · Cross-listed from cs.IR
The Multilingual Curse at the Retrieval Layer: Evidence from Amharic
Yosef Worku Alemneh, Kidist Amde Mekonnen and Maarten de Rijke
Multilingual retrieval increasingly underpins cross-lingual question answering and
retrieval-augmented generation. Strong zero-shot scores on
multilingual benchmarks are often taken as evidence that current encoders transfer reliably across many
languages. We argue that this assumption breaks down for underrepresented, morphologically rich
languages, and use Amharic as a diagnostic case. Under a shared passage
retrieval protocol covering dense, late-interaction, learned sparse, and cross-encoder paradigms, we compare zero-shot
multilingual retrievers, Amharic-fine-tuned
multilingual retrievers, and monolingual Amharic retrievers. The strongest zero-shot
multilingual retriever underperforms the strongest monolingual Amharic first-stage retriever by 23% relative MRR@10. Fine-tuning two recent
multilingual embedding models on the same Amharic supervision yields 32-60% relative MRR@10 gains over zero-shot, but the best Amharic-fine-tuned
multilingual model remains below the strongest monolingual Amharic retriever. These findings indicate that zero-shot
multilingual retrieval is not a sufficient proxy for equitable information access in the LLM era: for underrepresented
languages,
retrieval must be evaluated and adapted in-
language rather than inferred from aggregate
multilingual benchmarks. To foster future research, we publicly release the
dataset, codebase, and trained models at https://github.com/rasyosef/amharic-neural-ir.
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Machine Learning · Cross-listed from cs.AI
Jailbreak to Protect: Buffering and Reinforcing via Temporary Jailbreaking for Safe Fine-Tuning in Large Language Models
Seokil Ham, Jaehyuk Jang, Wonjun Lee et al. (+1 more)
Fine-tuning-as-a-Service (FaaS) enables personalization of large
language models (LLMs), but it can weaken safety-
alignment under harmful fine-tuning attacks. Recent work has shown that activating harmful-behavior modules during fine-tuning can prevent models from learning undesired behaviors, but its mechanism remains unclear. In this paper, we revisit temporary jailbreaking as a defense against harmful fine-tuning and provide a gradient-level analysis showing that it saturates safety-degrading gradients while preserving benign task-relevant gradients. Based on this insight, we propose a Buffer-and-Reinforce fine-tuning framework that buffers harmful updates during user fine-tuning and reinforces safety after adaptation. Specifically, BufferLoRA induces temporary jailbreaking as a removable adapter to reduce harmful updates during user fine-tuning. After adaptation, ReinforceLoRA, trained to recover refusal behavior under the temporarily jailbroken state, is integrated with UserLoRA via QR decomposition-based merging to reinforce safety while preserving user-task performance. Extensive experiments show that our framework achieves superior safety and utility with no additional safety data during user fine-tuning and minimal computational cost.
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All authors Seokil Ham, Jaehyuk Jang, Wonjun Lee, Changick Kim
Machine Learning
Deep ZakaiJ: Structured Filtering for Jump-Diffusion Time Series Forecasting
Yan Leng, Thibaut Mastrolia and Hao Wang
Time series driven by unobserved latent states frequently exhibit abrupt jump discontinuities whose timing and magnitude cannot be predicted from observed history alone. Classical jump-
diffusion models offer a principled mathematical framework but assume rigid parametric forms, while recent neural jump models operate on fully observed trajectories without inferring the hidden states that govern the dynamics. We propose Deep ZakaiJ, a latent-state model for partially observed jump-
diffusion systems that embeds the Zakai nonlinear filtering equation into a neural encoder–decoder architecture. The encoder recursively updates a belief over the latent state via Strang splitting into three interpretable substeps: prior propagation,
diffusion innovation, and jump innovation, yielding a differentiable, first-order-accurate approximation of the exact filtering
evolution. The decoder is a structured jump-
diffusion model explicitly conditioned on the filtered belief, preserving the separation between continuous dynamics and discontinuous shocks. On synthetic, financial, and oceanographic
datasets, Deep ZakaiJ improves distributional forecasts while remaining competitive in point accuracy, achieving calibrated predictive intervals and recovering interpretable latent structure in synthetic and qualitative case studies.
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Machine Learning
RL with Learnable Textual Feedback: A Bilevel Approach
Utsav Singh, Sidhaarth Sredharan, Souradip Chakraborty et al. (+1 more)
Reinforcement learning with verifiable rewards can improve LLM
reasoning, but learning remains sample-inefficient when terminal rewards are sparse. This has motivated a growing line of work on RL with textual feedback, where a critic model generates natural
language feedback to guide a
reasoning model (the actor), augmenting scalar rewards with richer learning signals. However, existing methods typically treat feedback as fixed or auxiliary, which misses a key property: feedback should not merely be correct, but should improve the policy (actor model) when provided in context. This motivates a paradigm of learnable textual feedback for RL. Yet the learnability and usefulness of feedback depend on the policy's ability to learn from it, making RL with learnable feedback an inherently bilevel problem. We formalize this coupling as a Stackelberg bilevel program and derive Bilevel Natural
Language Actor-Critic (Bi-NAC), which jointly trains a critic to generate reward-improving feedback and an actor to exploit it. Across MATH-500, MBPP, and GPQA, Bi-NAC improves sample and parameter efficiency over RL and fixed-critic baselines: our 2B model outperforms the 3B GRPO baseline, achieving 46.6% versus 41.4% on MATH-500, while our 6B model surpasses the 7B GRPO baseline, achieving 49.3% versus 43.6% on GPQA.
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All authors Utsav Singh, Sidhaarth Sredharan, Souradip Chakraborty, Amrit Singh Bedi
Machine Learning
Rethinking Federated Unlearning via the Lens of Memorization
Jiaheng Wei, Yanjun Zhang, He Zhang et al. (+5 more)
Federated learning (FL) increasingly needs machine unlearning to comply with
privacy regulations. However, existing
federated unlearning approaches may overlook the overlapping information between the unlearning and remaining data, leading to ineffective unlearning and unfairness between clients. In this work, we revisit
federated unlearning through the lens of memorization. We argue that unlearning should mainly remove the unique memorized information attributable to the data to be forgotten, while preserving overlapping patterns that are also supported by the remaining data. Specifically, we propose Grouped Memorization Evaluation, an example-level metric that separates memorized knowledge from overlapping knowledge. Building on this metric, we introduce
Federated Memorization
Pruning (FedMemPrune), a
pruning-based unlearning approach that resets redundant parameters responsible for memorization. Extensive experiments show that FedMemPrune closely matches retraining-based unlearning baselines while more effectively eliminating memorization than existing
federated unlearning
algorithms, yielding strong unlearning performance without sacrificing the utility of retained knowledge.
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All authors Jiaheng Wei, Yanjun Zhang, He Zhang, Leo Yu Zhang, Chao Chen, Kok-Leong Ong, Jun Zhang, Yang Xiang
Machine Learning · Cross-listed from cs.CR
AI-Driven Adaptive Adversaries and the Erosion of Cryptographic Trust in Public Key Systems
Petar Radanliev
This paper examines the erosion of Public Key Cryptography (PKC) security under adaptive
adversarial optimisation driven by artificial intelligence. The problem addressed is the growing mismatch between
algorithm-centric cryptographic security models and operational attack realities, where adversaries exploit implementation-level observability rather than breaking cryptographic primitives.
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Machine Learning
SemanticZip: A Pilot Framework for Lossy Text Compression with LLMs as Semantic Decompressors
Natalia Trukhina and Vadim Vashkelis
Text compression for large
language model (LLM) systems is usually framed as
token deletion,
retrieval, summarization, or exact reconstruction. We study a more aggressive but explicitly lossy setting: compress text into compact codes that an LLM can expand into task-relevant meaning. We call this setting SemanticZip. Unlike lossless compression, SemanticZip does not require byte-identical reconstruction; unlike ordinary summarization, it treats model-based decompression as part of the codec and evaluates whether task-relevant semantic commitments are recovered. This paper is a pilot framework, not a
benchmark claim. We formalize LLM-mediated decompression, define a protected/lossy packet architecture, and evaluate six representation regimes over five author-constructed diagnostic cases: structured prose, JSON, CCL-Core, CCL-Min, SemanticZip ASCII, and SemanticZip emoji. An independent decoder LLM reconstructs typed semantic atoms from each compressed representation, and we score Critical Atom Recall, Weighted Atom Recall, precision, and tokenizer gain. In this pilot, structured prose has the highest recoverability, with WAR = 0.956 and 19.1% o200k_base
token gain. CCL-Min is the strongest balanced point, with 39.4%
token gain and WAR = 0.874. SemanticZip ASCII provides the largest useful compression, with 46.5%
token gain and WAR = 0.802, while emoji-heavy SemanticZip performs worse on both compression and recovery. The main contribution is not the claim that these numbers establish a universal frontier. Rather, we introduce a reproducible experimental interface for studying lossy, LLM-decompressible text codes and a design principle: safety-critical and exact commitments should remain protected, while predictable low-risk context may be semantically zipped.
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Machine Learning · Cross-listed from cs.CR
Steering Beyond the Support: Adversarial Training on Unsupervised Jailbroken Activation Simulation
Luoyu Chen, Weiqi Wang, Zhiyi Tian et al. (+5 more)
Jailbreak
prompts can trigger harmful completions on aligned LLMs, In accordance, safety steering has been proposed: test-time activation interventions that steer jailbreak activations to trigger refusal while preserving benign utility. However, existing steering methods are fundamentally supervised and tied to a static, limited training set, whereas real jailbreaks evolve and are often out-of-distributed from the training set, leading to failures on unseen attacks. In this paper, we tackle the failure on unseen jailbreaks problem, base on unsupervised latent direction discovery. We propose a bi-level
adversarial training framework for zero-shot jailbreak defense. In the inner step, we simulate diverse jail-broken activations by extrapolating from refusal-state harmful-request activations via unsupervised latent direction discovery, which expands the coverage of real jailbreak activation subspaces. In the outer step, we train a potential-induced steering field to push these
adversarial jailbroken states into refusal regions while keeping benign unchanged. Across three LLMs and six classical jailbreak families, our method achieves strong defense with attack success rates mostly below 5%, and rising subspace coverage throughout training helps explain the improved generalization.
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All authors Luoyu Chen, Weiqi Wang, Zhiyi Tian, Chenhan Zhang, Feng Wu, Jianhuan Huang, Ahmed Asiri, Shui Yu
Machine Learning · Cross-listed from cs.AI
Learning Mental Models From Unreliable Evidence
Jeffrey Qin, Zhuangfei Gao, Wasu Top Piriyakulkij et al. (+4 more)
Children expertly construct mental models under uncertainty despite limited world knowledge. Which computational principles make this possible? We study this question in an interactive physical Box Task in which participants infer a latent cause through interaction with a
stochastic and partially observed environment. The Box Task was originally designed to study children's puzzle-solving qualitatively. We contribute a computational analysis of behavior that formalizes the cognitive process by which children generate new hypotheses and respond to environmental uncertainty as inference unfolds. Our modeling framework is based on
Bayesian particle-based inference, which maintains a small set of working hypotheses and continually generates new ones. We give two complementary implementations of hypothesis representations within this framework: (1) as constraints on evidence, and (2) as executable programs evaluated against evidence. Using the constraint-based formulation, we show that the model needs to account both for subjective reliability of evidence and online hypothesis generation to explain key signatures of children's behavior. Using the programmatic formulation, we show that hypotheses may take the form of partial compositional rules to guide information gathering when evidence interpretation is hard. The programmatic hypotheses are implemented using LLM-based program synthesis, evaluated across three
prompt variants and several LLM backends, demonstrating robustness of our approach. Together, these results extend current models of children's inference to account for subjective reliability of evidence and open-ended hypothesis spaces, and provide a computational analysis of the form generated hypotheses may take in practice.
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All authors Jeffrey Qin, Zhuangfei Gao, Wasu Top Piriyakulkij, Mia Radovanovic, Jessica Sommerville, Kevin Ellis, Marta Kryven
Machine Learning
What Are We Actually Decoding? Source Attribution for Non-Invasive Brain-to-Language Retrieval
Xinyu Zhang, Sichao Liu, Runhao Lu et al. (+2 more)
In non-invasive neural
language decoding, results can be inflated by sources that are not stimulus-evoked neural evidence: decoder priors,
embedding-based metrics, and non-neural structural nuisances such as signal duration. The methodological challenge is therefore attribution: a reported gain is more informative when it can be traced to a specific source. We recast stimulus-locked MEG-to-audio
retrieval as an
auditing framework that separates apparent performance into three sources - structural shortcuts, window-level stimulus-locked evidence, and cross-window contextual aggregation - and provides a diagnostic for each. Signal-blind Gaussian noise reaches 66.3% Rank@1 (R@1) under variable-length decoding but collapses to near chance once fixed-duration windows and stimulus-identity splits are enforced, isolating structural leakage. Under these controls, fixed-window
retrieval recovers measurable MEG-audio discriminability, while an oracle sentence-bucket diagnostic shows that 95.7% of Top-1 errors select the wrong sentence, localising the residual bottleneck to sentence-level competition. We audit this contextual source with Group Context Bias (GCB), an inference-time additive logit bias that pools sentence-consistent evidence across windows while leaving the base
retrieval scores and candidate pool fixed. Used as a score-space intervention, GCB makes the contextual source measurable: R@1 shifts from 44% to 52% on Gwilliams and from 22% to 29% on MOUS under the same fixed setting. GCB is auditable under this design: its effect collapses under random-grouping perturbations and vanishes when local evidence is attenuated in MEG or is near chance in
EEG, supporting its use as a controlled source-attribution intervention. These results suggest that
brain-to-
language performance should be source-attributed, not merely reported.
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All authors Xinyu Zhang, Sichao Liu, Runhao Lu, Alexandra Woolgar, Lihui Wang
Machine Learning
MindAlign: Bridging EEG, Vision, and Language for Zero-Shot Visual Decoding
Zexuan Chen, Sichao Liu, Runhao Lu et al. (+4 more)
Visual decoding from
brain signals is a key challenge at the intersection of computer
vision and neuroscience, requiring methods that bridge neural representations and computational models of
vision. We introduce a tri-modal contrastive framework for
EEG-based visual decoding that aligns
EEG, visual, and textual representations within a unified latent space. Our approach follows a two-stage design. First, we pre-train an
EEG encoder via masked reconstruction on unlabeled trials, learning spatio-temporal regularities that transfer robustly to downstream tasks. Second, we jointly align
EEG, image, and LLM-generated textual descriptions through contrastive learning, where text supervision acts as a semantic regularizer that injects linguistic structure into the shared space without overwhelming the primary
EEG-image signal. The encoder integrates subject-specific adaptation, graph-
attention over channels, and temporal-spatial convolutional
embeddings. On the Things-
EEG2 200-way zero-shot
benchmark, our framework achieves 54.1% Top-1 and 83.4% Top-5 accuracy, substantially exceeding the strongest prior baseline (32.4% / 64.0%), with paired Wilcoxon tests confirming significance (p < 0.01) over all in-subject baselines. We validate generalization on Things-MEG. Analysis reveals that compact
embedding geometries (CN-CLIP) outperform much larger backbones, and that decoding aligns with established neurophysiology of visual processing. This work is a critical step towards robust, semantically-grounded visual decoding from non-invasive temporal neural signals. The source code is publicly available in https://github.com/anon-
eeg/
eeg_image_decoding.
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All authors Zexuan Chen, Sichao Liu, Runhao Lu, Huichao Qi, Alexandra Woolgar, Xi Vincent Wang, Lihui Wang
Machine Learning · Cross-listed from q-bio.GN
AnnotateMissense: a genome-wide annotation and benchmarking framework for missense pathogenicity prediction
Muhammad Muneeb and David B. Ascher
Missense variant interpretation remains challenging because pathogenicity depends on heterogeneous evidence from population frequency, evolutionary conservation, transcript context, amino acid substitution severity, prior pathogenicity predictors and
protein-
language-model-derived features. We present AnnotateMissense, a scalable annotation, benchmarking and genome-wide prediction framework for missense variant interpretation. AnnotateMissense integrates hg38 missense variants derived from dbNSFP v5.1 with ANNOVAR annotations, dbNSFP transcript/
protein descriptors, AlphaMissense scores, ESM-derived features, conservation metrics, population-frequency variables, established pathogenicity predictors and engineered amino acid/codon-context features. Using 132,714 ClinVar-labelled missense variants, we benchmarked machine-learning and deep-learning models under controlled feature configurations. The full 303-feature
benchmark set achieved the strongest performance with XGBoost, reaching mean MCC = 0.9411 and ROC-AUC = 0.9950 across stratified five-fold cross-validation. Restricted naive and location-oriented feature sets achieved lower best MCC values of 0.4989 and 0.5113, respectively. Circularity-controlled ablations showed that removing prior-predictor, population-frequency and clinically overlapping evidence reduced performance, whereas excluding AlphaMissense and ESM-derived features alone had minimal effect. Temporal ClinVar validation on newly observed pathogenic/benign variants achieved MCC = 0.7613, accuracy = 0.8798 and F1-score = 0.8750. The final model was applied to 90,643,830 hg38 missense variants to generate AnnotateMissense pathogenicity scores and binary prediction labels. Code and outputs are available at https://github.com/MuhammadMuneeb007/CAGI7_Annotate_All_Missense and https://doi.org/10.5281/zenodo.19981867.
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Machine Learning
ECHO: Terminal Agents Learn World Models for Free
Vaishnavi Shrivastava, Piero Kauffmann, Ahmed Awadallah et al. (+1 more)
CLI
agents are the closest thing
language models have to an
embodied setting: the model emits commands, the terminal executes them, and the returned stream – stdout, errors, files, logs, and traces – records the consequences. We argue that this stream is a supervision signal, but standard
agent RL discards it: GRPO-style training updates action
tokens with sparse outcome-level rewards while ignoring environment responses already in the rollout. Failed rollouts provide little policy-gradient signal despite containing rich evidence about how the environment responds. We introduce ECHO (Environment Cross-
entropy Hybrid Objective), a hybrid objective that combines the standard policy-gradient loss on action
tokens with an auxiliary loss that trains the policy to predict environment observation
tokens resulting from its own actions. ECHO reuses the same forward pass as GRPO, requires no additional rollouts, and turns terminal feedback into dense supervision for all rollouts. ECHO doubles GRPO pass@1 on TerminalBench-2.0: Qwen3-8B improves from 2.70% to 5.17%, and Qwen3-14B from 5.17% to 10.79%. ECHO also produces policies that better predict terminal dynamics, even on trajectories they did not generate: across held-out rollouts, it sharply reduces environment-
token cross-
entropy while GRPO alone barely changes it. From base Qwen3-8B, ECHO matches expert-SFT-then-GRPO performance on held-out terminal tasks without expert demonstrations, and recovers roughly half of the expert-SFT initialization benefit on TerminalBench-2.0. In some settings, the environment prediction loss alone enables verifier-free self-improvement, allowing policies to improve on unseen OOD tasks by learning only from environment interactions. Together, these results suggest that environment observations are not merely context for future actions, but a dense, on-policy supervision signal already present in every rollout.
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All authors Vaishnavi Shrivastava, Piero Kauffmann, Ahmed Awadallah, Dimitris Papailiopoulos
Machine Learning
Lake Detection and Water Quality Estimation in Sentinel-2 Data
Iulia Pleşu, Alexandra Băicoianu and Ioana Cristina Plajer
With
climate change and increasing human pressure on natural landscapes, inland water resources are becoming progressively scarcer, more vulnerable, and more difficult to manage sustainably. Reliable and automated methods for detecting, monitoring, and assessing surface water bodies are therefore of growing scientific and practical importance. In this paper, we investigate and compare three distinct machine learning architectures for water body identification and monitoring. Their performance is evaluated through quantitative metrics and real-world examples. Furthermore, a direct comparison with classical NDWI thresholding is conducted on a representative test image to highlight differences between data-driven and index-based approaches. This analysis allows us to identify the best-performing model in terms of accuracy, robustness, and practical applicability. Beyond detection, a major challenge for meaningful water quality assessment lies in the consistent and interpretable visualization of spectral water indices. Standard color mapping techniques are often inadequate or potentially misleading for environmental applications. To address this gap, we propose a suite of meaningful color schemes adapted for water quality indices, facilitating clearer interpretation, comparison, and decision-making for human users.
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Machine Learning
Zeroth-Order Nonconvex Nonsmooth Optimization with Heavy-Tailed Noise
Zhuanghua Liu and Luo Luo
This paper considers the nonconvex nonsmooth problem in which the objective function is Lipschitz continuous. We focus on the
stochastic setting where the
algorithm can access
stochastic function value evaluations with heavy-tailed noise, which is prevalent in many popular machine learning applications. We propose a
stochastic zeroth-order
algorithm that refines the framework of online-to-nonconvex conversion by clipping the two-point gradient
estimator. The theoretical analysis shows that our
algorithm can find a $(\delta, \epsilon)$-Goldstein stationary point with zeroth-order oracle complexity of ${\mathcal O}(d^{\frac{p}{2(p-1)}}\delta^{-1}\epsilon^{-\frac{2p-1}{p-1}})$, where $d$ is the problem dimension and $p\in(1,2]$ is the order of bounded moments. Note that our dependence on dimension $d$ matches the best-known results of
stochastic zeroth-order optimization for finding the sub-optimal solution of a
stochastic convex nonsmooth problem. In addition, our dependence on accuracy parameters $\delta$ and $\epsilon$ is consistent with that of the best-known
stochastic first-order
algorithms for
stochastic nonconvex nonsmooth problems. Finally, we conduct numerical experiments to demonstrate the effectiveness of the proposed method.
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Machine Learning · Cross-listed from cs.CV
{\Phi}-Noise: Training-Free Temporal Video Conditioning via Phase-Based Noise Manipulation
Ofir Abramovich, Nadav Z. Cohen, Adi Rosenthal et al. (+1 more)
Latent
video diffusion models generate
videos by progressively transforming Gaussian noise into realistic samples conditioned on text or visual inputs. However, existing conditioning methods often require additional training and computational overhead. Motivated by recent findings on the importance of frequency components in generative models, we propose a simple, training-free approach for motion-conditioned
video generation by injecting low-frequency phase information from a reference
video directly into the
diffusion noise latents. Our method transfers motion cues without modifying the model architecture or inference pipeline. Using several applications, we demonstrate effective control over both appearance and dynamics in generated
videos, while achieving competitive or superior results compared to more complex conditioning approaches.
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All authors Ofir Abramovich, Nadav Z. Cohen, Adi Rosenthal, Ariel Shamir
Machine Learning · Cross-listed from cond-mat.stat-mech
Implicit Binarization via Complex Phase Dynamics in Combinatorial Optimization
Khen Cohen, Mark Glass, Meir Feder et al. (+1 more)
We introduce a physics-inspired continuous relaxation framework that yields substantially improved solutions for NP-hard combinatorial optimization problems, including Quadratic Unconstrained Binary Optimization (QUBO), binary sparse coding, and planted-solution Ising models. By parameterizing discrete binary variables as continuous wave-like states on the complex unit circle, we inherently smooth highly non-convex energy landscapes. We show that representing binary variables as complex phases reveals an implicit regularization mechanism that promotes convergence toward discrete states. Extracting this mechanism yields significant improvements even within standard real-valued optimization frameworks, using this regularizer explicitly. Empirically, this regularization yields vastly higher ground-state convergence rates than standard real-valued alternatives. Our models achieved zero error in large-scale 160x160 QUBO tasks under severe noise (sigma=0.25), and outperformed traditional
algorithms (OMP and LASSO) in underdefined sparse coding with perfect recovery at sigma=0.15. The solver's robustness was further validated by recovering exact ground-state configurations in 8 out of 11 rigorously engineered planted-solution
benchmarks.
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All authors Khen Cohen, Mark Glass, Meir Feder, Yaron Oz
Machine Learning · Cross-listed from cs.AI
Market Regime Council for Dynamic Credit Assignment in Multi-Agent LLM Decision Systems
Yunhua Pei, Zerui Ge, Jin Zheng et al. (+1 more)
Multi-
agent LLM decision systems for portfolio management still lack a principled way to assign credit across specialist
agents, remain vulnerable to cold-start dominance under regime shifts, and offer limited transparency into how final allocations are formed. We propose
Market Regime Council (MRC), a cooperative multi-
agent decision system that computes exact Shapley credits across all single, pairwise, and Grand-coalition outputs for online
agent weighting. Instantiated with N=3 specialist
agents, at each trading period, MRC recomputes coalition-based Shapley weights from exponentially weighted performance histories, uses a
Bayesian adaptive mixture to stabilize early periods, applies regime-dependent multipliers to adjust
agent authority, and records each rebalance through a five-layer causal trace. Over 1,037 trading days across 13 crypto assets and five seeds, MRC achieves a Sharpe ratio of 1.51 and a cumulative return of 440.1%, ranking first on CR, SR, and IR among active baselines and attaining the lowest MDD among active methods. Ablation results show that the gains come from Shapley-weighted integration across coalition outputs rather than from any single stage in isolation. Code and demo data are included in the supplementary material.
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All authors Yunhua Pei, Zerui Ge, Jin Zheng, John Cartlidge
Machine Learning · Cross-listed from cs.AI
SPACE: Unifying Symmetric and Asymmetric Routing Problems for Generalist Neural Solver
Rongsheng Chen, Changliang Zhou, Canhong Yu et al. (+4 more)
Generalist neural routing solvers have shown great potential in solving diverse vehicle routing problems (VRPs) with a unified model. However, existing solvers are typically limited to symmetric settings or degrade in performance when switching to asymmetric settings due to input inconsistencies or inherent structural differences, substantially limiting their practicality in real-world scenarios that encompass both scenarios. To address this limitation, we define the spatial position of each node based on the relative distances to a specific set of pivots and further propose a Spatial Pivot-Aligned Coordinate-free
Embedding (SPACE) framework that unifies node representation and solution generation across symmetric and asymmetric VRPs. Specifically, we construct a bidirectional Frechet representation using a novel furthest pivot sampling strategy to enable invariant node representations across distinct problem settings. Furthermore, we introduce a weight-decomposed adaptive decoding mechanism that decouples
geometric perception from problem representations, mitigating the overfitting of constraint decisions to a specific geometry setting. Extensive experiments on 110 VRP variants, comprising 55 symmetric problems and their asymmetric counterparts, demonstrate that SPACE achieves promising zero-shot generalization in both symmetric and asymmetric VRPs.
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All authors Rongsheng Chen, Changliang Zhou, Canhong Yu, Yuanyao Chen, Yu Zhou, Zhuo Chen, Zhenkun Wang
Machine Learning
The Normalized Maximum Likelihood for Regular Non-Smooth Models: Measure-Theoretic Foundations and Geometric Sampling
Trenton Lau and Gary P. T. Choi
The Normalized Maximum Likelihood (NML) codelength, or
stochastic complexity, represents a principled criterion for universal coding. While recent coarea-based formulations provided a calculation method for smooth models, this framework collapses for the non-smooth
estimators ubiquitous in modern machine learning (e.g., Lasso, Sparse SVMs). In this work, we provide a rigorous framework for computing the NML for regular path-differentiable Lipschitz (PDL)
estimators. By applying classical
geometric measure theory and bridging the coarea formula with conservative Jacobians, we prove that the
stochastic complexity for non-smooth models is well-posed and theoretically consistent with the outputs of modern Automatic Differentiation. To compute this quantity exactly, we introduce the Propose-and-Project Metropolis-Hastings (PDL-PPMH) sampler, a
geometric MCMC
algorithm capable of traversing the non-differentiable level sets of the maximum likelihood
estimator. We theoretically justify its components, including a
stochastic tangent space proposal and a provably convergent non-smooth projection solver. We demonstrate the method's robustness by sampling from a high-dimensional Lasso posterior ($P=2000$), while simultaneously quantifying the computational scaling that governs the trade-off between exactness and mixing time. Crucially, we empirically demonstrate that our exact NML criterion provides a highly data-efficient alternative to cross-validation, achieving statistically indistinguishable predictive optima without requiring data splitting. Altogether, our work paves the way for the theoretical analysis of the NML codelength for regular non-smooth models.
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Machine Learning
Balancing Fairness, Privacy, and Accuracy: A Multitask Adversarial Framework for Centralized Data-Driven Systems
Imesh Ekanayake, Elham Naghizade and Jeffrey Chan
The integration of
fairness and
privacy in centralized data-driven applications is critical, especially as these systems increasingly influence sectors with significant societal impact. Current methods rarely address
privacy,
fairness, and accuracy together, which can potentially compromise ethical standards and
privacy regulations. However, balancing these three objectives is quite challenging since each of objective often imposes conflicting requirements on the design and training of models, making it difficult to optimize one without compromising the others. This paper introduces a novel multitask
adversarial model that treats
fairness and
privacy as integral objectives rather than afterthoughts, and learns a latent representation that hides sensitive attributes while preserving essential task-related information. Our approach dynamically balances
fairness with accuracy and
privacy through an optimized cost function with minimal performance loss even under strict conditions. Extensive testing on diverse
datasets shows the ability of our model to achieve high standards of
fairness and
privacy without significant sacrifice to accuracy. Benchmarking against state-of-the-art
privacy and
fairness standards shows that our method enhances the robustness of
privacy,
fairness, and accuracy optimization, proving its adaptability across various
datasets.
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Machine Learning · Cross-listed from eess.SY
Asymmetric Adaptation-based Real-time Fault Diagnosis Under Transitional Operating Conditions
Hongshuo Zhao, Zeyi Liu and Xiao He
Data streams in real-world industrial scenarios often contain transitional operating conditions that are uncovered during offline training, leading to significant distribution shifts. To bridge the gap between static offline models and dynamic online data, a novel asymmetric adaptation-based fault diagnosis method is proposed in this paper. Specifically, in the offline stage, we employ domain generalization techniques to extract domain-invariant features from multiple stable conditions and construct robust normalized fault prototypes as reference anchors. Subsequently, during online inference, we design an online test-time adaptation method based on a periodic prototype re-projection mechanism to dynamically update prototype positions. Furthermore, we utilize the
geometric distribution derived from anchors to guide the updates of classifiers and adopt an asymmetric learning rate strategy for the feature extractor and classifier. The proposed approach ensures rapid adaptation to new transitional conditions while preserving the discriminative power inherited from the offline domain generalization initialization. Experimental results demonstrate that this mechanism effectively leverages offline generalized knowledge to guide online inference, significantly improving robustness in non-stationary environments.
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Machine Learning · Cross-listed from cs.CL
Temporal Concept Drift in Legal Judgment Prediction: Neural Baselines Across Three Epochs of Ukrainian Court Decisions
Volodymyr Ovcharov
Legal NLP
benchmarks evaluate models on randomly split data, implicitly assuming that legal
language is stationary. We test this assumption by fine-tuning four
transformer encoders – XLM-RoBERTa (base and large) and their legal-domain variants – on Ukrainian court decisions from three temporal epochs defined by geopolitical disruptions: pre-war (2008-2013), hybrid war (2014-2021), and full-scale invasion (2022-2026). Each model is trained on one epoch and evaluated on all three, producing a 3x3 cross-temporal generalization
matrix. Four findings emerge. (1) Forward degradation is severe: models trained on pre-war data lose up to 27.2 percentage points of macro-F1 when applied to full-scale invasion era decisions. (2) The degradation is asymmetric: backward transfer (full-scale to pre-war) is substantially more robust than forward transfer, consistent with the hypothesis that legal
language is additive. (3) Legal-domain pretraining (Legal-XLM-R) does not improve absolute performance but reduces forward degradation magnitude and asymmetry. (4) Chronological continual learning eliminates catastrophic forgetting for general XLM-R: pre-war knowledge is fully retained (+1.8 to +6.2 pp) while full-scale performance gains +16.5 to +19.0 pp; reverse-chronological training causes severe forgetting. Cross-jurisdictional pretraining on Swiss Judgment Prediction data improves absolute performance but does not reduce temporal degradation magnitude, confirming that temporal drift is an intrinsic property of legal
language evolution. The
dataset (428K decisions across three epochs) is publicly available as a LEXTREME contribution.
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Machine Learning · Cross-listed from cs.RO
Vision-Guided Outdoor Flight and Obstacle Evasion via Reinforcement Learning
Shiladitya Dutta, Aayush Gupta, Varun Saran et al. (+1 more)
Although quadcopters boast impressive traversal capabilities enabled by their omnidirectional maneuverability, the need for continuous pilot control in complex environments impedes their application in GNSS and telemetry-denied scenarios. To this end, we propose a novel sensorimotor policy that uses stereo-
vision depth and visual-inertial odometry (VIO) to autonomously navigate through obstacles in an unknown environment to reach a goal point. The policy is comprised of a pre-trained autoencoder as the perception head followed by a planning and control LSTM network which outputs velocity commands that can be followed by an off-the-shelf commercial drone. We leverage reinforcement and privileged learning paradigms to train the policy in simulation through a two-stage process: 1) initial training with optimal trajectories generated by a global motion planner acting as a supervisory backbone, 2) further fine-tuning in a curriculum environment. To bridge the sim-to-real gap, we employ domain randomization and reward shaping to create a policy that is both robust to noise and domain shift. In outdoor experiments, our approach achieves successful zero-shot transfer to both obstacle environments and a drone platform that were never encountered during training.
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All authors Shiladitya Dutta, Aayush Gupta, Varun Saran, Avideh Zakhor
Machine Learning
CAffNet: Hard Constraint-Affine Neural Networks
Yang Zhao, Jungeun Lee, Jeong hwan Jeon et al. (+1 more)
We present a novel framework for
embedding hard constraint satisfaction into neural network (NN) architectures, specifically feedforward neural networks and
transformers, with input-dependent affine constraints of arbitrary cardinality. Traditional constraint enforcement approaches either rely on penalty-based soft constraints, which offer no guarantee of satisfaction, or on post-processing methods that enforce constraints after the NN is trained, which may lead to suboptimality. We introduce a trainable constraint-affine (CAffine) layer into NNs, yielding CAffNet, which goes beyond enforcing affine constraints via fixed orthogonal or parallel projections and enables joint optimization with network parameters. Moreover, we impose no restrictions on the constraint space dimensions and establish that our construction preserves the universal approximation properties of NNs, while providing provable guarantees on constraint adherence for all inputs. Experimental validation demonstrates robust performance across diverse domains requiring guaranteed constraint satisfaction. The code is available at https://github.com/ice-t-lab/CAffNet.git.
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All authors Yang Zhao, Jungeun Lee, Jeong hwan Jeon, Sze Zheng Yong
Machine Learning · Cross-listed from cs.MA
A Reinforcement Learning Inspired Latent Yield Based Adaptive Algorithm Switching Mechanism
Jayprakash S. Nair, Jimson Mathew and Shivashankar B. Nair
Selecting the most suitable
algorithm for a given problem instance remains a challenging task, particularly in online or dynamic environments where problem characteristics evolve over time. Relying solely on instantaneous performance metrics can result in a reactive and unstable behaviour, often leading to suboptimal
algorithm switching. This paper introduces a computationally efficient approach for aggregating an
algorithm's performance across multiple problem instances that is fairly immune to erratic variations in instance features. Inspired by features inherent to Reinforcement Learning (RL), this technique encapsulates rewards and penalties into a latent yield that, in turn, triggers exploitation and exploration, consequently resulting in adaptive
algorithm switching. The proposed technique employs island models, inspired by Genetic
Algorithms, to facilitate parallel exploration and performance exchanges among
algorithm populations inhabiting local repertoires. Experimental evaluations on sorting
algorithms and robotic obstacle avoidance tasks demonstrate the feasibility and effectiveness of the approach, highlighting its potential in domains where adaptive
algorithm selection is critical.
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Machine Learning · Cross-listed from cs.RO
Smoother Action Chunking Flow Policy via Prior-Corrected Orthogonal Trust-Region Guidance
Kai Fang, Hailong Pei and Xuemin Chi
Flow-matching
robot policies commonly use action-chunking inference for efficient closed-loop control, but chunk boundaries can introduce discontinuous action transitions. Existing RTC guidance improves continuity by injecting correction signals during denoising, yet its weight schedule is weak at intermediate timesteps and its unconstrained correction direction may introduce transverse perturbations. We propose POTR, a **p**rior-corrected **o**rthogonal **t**rust-**r**egion guidance method. First, we incorporate a data-prior scale $\sigma_d$ into the RTC guidance weight, yielding stronger intermediate-time correction. Second, we decompose the guidance vector into components parallel and perpendicular to the denoising velocity, and constrain the perpendicular component within a trust region. On LIBERO with $\pi_{0.5}$, POTR improves success rate and consistently reduces chunk-boundary discontinuity, acceleration, and jerk compared with RTC. Ablations show that the prior-corrected weight provides the main correction gain, while the orthogonal trust region further improves stability.
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Machine Learning
Representation-Guided Discrete Molecular Graph Retrosynthesis
Jiahai Huang, Anjie Qiao, Zhen Wang et al. (+2 more)
Stochastic process-based molecular graph generators have become the state of the art for template-free single-step retrosynthesis. However, these models are typically trained only on product-reactant pairs, thereby acquiring chemistry-relevant representations in an indirect and implicit manner. Meanwhile, recent advances in computer
vision demonstrate that offering representation guidance to a generator can effectively distill semantics from pretrained encoders into DiTs, substantially improving both convergence and generation quality. Whether similar gains extend to the retrosynthesis task, and what graph-specific design choices can make them work, remains an open question. To address these questions, we conduct a systematic empirical study over a unified design space spanning teacher molecular representations, endpoint and granularity choices, injection depths in the denoiser, correspondence strategies and guidance scheme. Guided by these considerations, we develop Graph-oriented Representation Guidance (GRG), which achieves 58.6 / 77.2 / 83.4 / 87.1 top-1 / 3 / 5 / 10 accuracy on USPTO-50k, while increasing diversity to 15.5, both substantially outperforming the adopted base generator. Notably, GRG consistently improves all top-k metrics in out-of-distribution settings, suggesting that representation guidance facilitates the acquisition of intrinsic chemical semantics. Meanwhile, the introduced representation guidance reduces the number of epochs by 35% and the wall-clock time by 30% to reach comparable performance. In addition, we introduce a simple yet effective representation-similarity-based reranking mechanism, which further improves the top of the ranked list without training an additional verifier.
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All authors Jiahai Huang, Anjie Qiao, Zhen Wang, Defu Lian, Yutong Lu
Machine Learning
Momentum Streams for Optimizer-Inspired Transformers
Jingchu Gai, Nai-Chieh Huang and Jiayun Wu
The residual update of a pre-norm
Transformer layer admits an interpretation as one step of a first-order optimizer acting on a surrogate
token energy, wherein the
attention and MLP sublayers function as gradient oracles. Based on this observation, we build a family of optimizer-inspired
Transformers (triple-momentum, Adam/AdamW,
Muon, SOAP) and compare them under matched compute. In our main pretraining experiment, the triple-momentum TMMFormer achieves the lowest validation loss, outperforming the vanilla
Transformer and prior architectural variants. A controlled ablation and supporting theory show that momentum, not preconditioning, is the main source of the gain. We further show that TMMFormer and other momentum-based designs reach flatter minima than the vanilla
Transformer, which leads to less forgetting and better generalization.
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