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Computer Science

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Monday 24 August

Systems and Control · Cross-listed from math.DS

Identifying Probability Localization Dynamics via Structured Stochastic Liftings

This work develops a discrete-time framework for identifying probability localization dynamics through finite stochastic representations adapted in space, time, memory, and state information. A compact dynamically relevant set is localized by a finite measurable partition, producing an observable probability state and a relational graph of admissible transitions. Structured stochastic liftings derived from Stochastically Structured Reservoir Computing (SSRC) give lossless polynomial representations of the observable state, while stochastic delay liftings add finite observable memory. These are distinguished from dynamically informed state-space enrichment: refinement of observational fibers containing states with the same present observation but different observable futures, yielding an exact obstruction-to-closure criterion. A route-network toy problem gives a minimal obstruction example, while four numerical laboratories (rotational phase dynamics, the chaotic logistic map, the Van der Pol oscillator, and a synthetic cyclic inventory system) show how spatial scale, temporal scale, polynomial degree, and delay depth interact. The logistic map isolates representation-induced memory in an otherwise Markovian chaotic system, using its exact invariant law as an ergodic benchmark and its zero-mass pseudospectrum to separate relaxation from transient amplification. An exact rotational cycle calibrates pseudospectra as a robustness diagnostic rather than a closure certificate. The inventory example gives a closure-driven enrichment procedure: residence-age hazards trigger age-refined states that improve predictive scores. These results motivate a minimal adequate representation: the least complex representation meeting predictive, structural, and identifiability requirements.
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Information Theory

Soft GRAND under Channel Switching and Drift

Under channel switching or drift, the posterior used to order Guessing Random Additive Noise Decoding (GRAND) queries can differ from the matched correction posterior, increasing query rank and finite-budget error. We bound log query rank by matched posterior self-information plus positive log-posterior mismatch; exact random-subset collision probabilities bound GRAND with abandonment (GRANDAB) error. Under switching, a state-path mixture achieves vanishing error uniformly over admissible paths below the minimum constituent capacity when log path-class size is sublinear and uniform input is capacity achieving. Under drift, pilot refresh bounds mismatch and yields a continuous refresh-period minimizer. Generalized-Gaussian BPSK simulations evaluate both regimes.
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Cryptography and Security

The Colossus with Feet of Clay: Debunking Encrypted Traffic Classifiers under PQC Evolution

Encrypted traffic classifiers often achieve high accuracy under matched training and testing conditions, implicitly assuming that deployment traffic follows the training distribution. TLS migration toward post-quantum cryptography (PQC) challenges this assumption because hybrid key establishment can reshape observable traffic without changing application labels. We frame this change as PQC-induced protocol drift and study its effects through closed-world HTTPS website fingerprinting using the deployed TLS~1.3 Hybrid-PQC group \texttt{\detokenize{X25519MLKEM768}}. We build a controlled, PQC-aware benchmark pairing Traditional (Non-PQC) and Hybrid-PQC traffic, then evaluate five representative classifiers and side-channel representations under matched-domain, cross-domain, and deployment-ratio settings. Collectively, the experiments show that PQC evolution does not remove learnable website information. Instead, it changes how that information appears in traffic, causing classifiers and feature combinations that perform well in-domain to lose reliability across cryptographic domains. By exposing the fragility of matched-domain evaluation, we offer strategic guidance, identify cross-domain robustness as a research priority, and recommend protocol-aware practices for dependable real-world encrypted traffic classification. The code is available at http://anonymous.4open.science/r/PQ-WF-Eval.
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All authors Bingzhen Li, Lingjia Meng, Runhan Song, Chuanzhou Pan, Tongjun Pu, Ziqiang Ma, Yupeng Jiang, Lei Cui, Zhiyu Hao

Machine Learning

Maximum-distance nonnegative matrix factorization for unmixing highly mixed grain-size distribution data

Unmixing grain-size distribution data into several end-members can help reveal sediment provenance, transport, and sedimentation processes. Traditional end-member unmixing methods seek end-members closely to specimens, which is suitable when data is poorly mixed. However, these methods can be limited for highly mixed data when the observed specimens are not near to the underlying end-members. To overcome this limitation, we introduce a maximum-distance nonnegative matrix factorization model that encourages the estimated end-members to be as distinct as possible. We adopt a hierarchical alternating least squares algorithm for optimization and analyze the convergence properties. We evaluate its performance on simulated grain-size distribution data and compare it with existing method. The results illustrate the potential of the proposed approach for end-member unmixing in highly mixed data.
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Computer Vision

Contextrast++: Robust Multi-Scale Contextual Contrastive Learning for Semantic Segmentation

Semantic segmentation has rapidly advanced with deep learning; however, challenges remain in effectively capturing local and global contexts as well as addressing the long-tailed distribution problem. To tackle these issues, we present Contextrast++, a robust contrastive learning method for semantic segmentation that improves multi-scale feature integration and mitigates class imbalance issues. Our method consists of two key components: 1) contextual contrastive learning (CCL) and 2) boundary-aware negative (BANE) sampling. CCL includes three subcomponents: adaptive fusion module, pixel-to-anchor (PA) loss, and anchor-to-anchor (AA) loss. The adaptive fusion module dynamically balances local and global feature integration, resulting in a more context-aware representation. While the PA loss leverages the fused multi-scale features to improve feature representation learning, the AA loss focuses on addressing the long-tailed distribution problem by utilizing a memory bank that stores a fixed number of class-balanced representative anchors. Meanwhile, BANE sampling enhances segmentation precision by selecting hard negatives from misclassified boundary regions, which refines fine-grained details during contrastive learning. As verified in extensive experiments using public datasets, we demonstrate that Contextrast++ substantially improves semantic segmentation performance over existing contrastive learning-based state-of-the-art approaches, while introducing no additional computational overhead during inference.
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All authors Changki Sung, Hyungtae Lim, Wanhee Kim, Youngwoo Seo, Hyun Myung

Robotics

RACO: Reliability-Aware Coarse-Goal Optimization for Inspection-Oriented UAV Vision-Language Navigation

UAV vision-language navigation (UAV-VLN) is commonly evaluated as goal reaching, but inspection-oriented deployment requires the agent to stop within a valid inspection region and avoid falsely confirming visually or semantically similar distractors. This requirement exposes a key weakness in existing coarse-to-fine UAV-VLN policies: the coarse goal predicted before local refinement is often treated as reliable, although it may drift toward plausible but incorrect object regions and limit the ability of the local stage to recover. To systematically evaluate this problem, we introduce LG-UVI, an object-centric inspection evaluation setting derived from CityNav/CityRefer. LG-UVI extends standard UAV-VLN episodes with target objects, hard distractors, type-aware inspection regions, and diagnostics for inspection-region arrival and object-level confirmation. To address this inspection-oriented setting, we further propose RACO, a reliability-aware adaptive coarse-to-fine navigation framework. Instead of treating the predicted coarse goal as a fixed waypoint, RACO views it as a runtime hypothesis and uses object-level candidate anchors to check and correct coarse localization before Stage 1 and at the Stage 1-to-Stage 2 boundary. RACO also applies scale-adaptive terminal refinement to handle terminal near-miss cases using runtime-observable geometric and anchor-based evidence. Under a unified online evaluation protocol, RACO improves SR over the reproduced HETT baseline by 9.53 and 7.98 percentage points on validation-unseen and test-unseen, respectively. It also improves inspection-region arrival and reduces false verification risk, showing that coarse-goal reliability optimization is an effective complement to existing coarse-to-fine UAV-VLN policies.
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All authors Sen Wang, Yiming Sun, Jiaxuan He, Pengfei Zhu

Artificial Intelligence

Robustness Analysis of Agentic AI to Inconsistent and Incomplete Tool Responses

Tool-using agents increasingly rely on external tools to complete multi-step tasks, but tool returns can fail in different ways and require different recovery actions. Existing robustness studies often use uncertainty-based measures to detect when an agent becomes unreliable. These measures can reveal that something has gone wrong, but they do not directly identify the type of tool failure or the appropriate response. We address this limitation by analyzing tool failures at the moment a return enters the agent context. Our approach combines two complementary signals. The first compares the likelihood of the returned content under the tool schema and under the full trajectory prefix. The second measures the agent's probability distribution over its legal next actions. We evaluate the approach by injecting incomplete and inconsistent returns into a retail customer-service benchmark. The results show that likelihood-based signals clearly capture incomplete returns and some direct inconsistencies, while action-based signals reveal how strongly a failure changes the next decision. Some failures that are weak under likelihood signals can still redirect the agent toward state-changing actions. These findings show that tool failures can be recognized at the return boundary, but reliable diagnosis requires combining multiple signals.
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All authors Jiachen Xu, Torben Bach Pedersen, Zhongming Yao, Xiaoyu Zhang, Yushuai Li

Robotics

VikPath: A Vision Kansformer Framework for Effective Obstacle Avoidance in Self-Supervised Pathfinding

Pathfinding is a fundamental problem in artificial intelligence and autonomous systems. Traditional heuristic-based algorithms, such as A*, rely on predefined heuristic functions to guide the search process. Although effective in structured environments, their search efficiency can degrade substantially in complex, obstacle-rich scenarios, where handcrafted heuristics may provide limited guidance. Recent studies have explored learning-based approaches to improve pathfinding efficiency; however, most existing methods rely on supervised learning and require labels generated by conventional planners or obtained through manual annotation. As a result, their performance is inherently influenced by the quality of the underlying supervision and may degrade when the labeling heuristics fail to capture complex environmental structures. Moreover, existing methods primarily optimize for path length while paying limited attention to obstacle clearance and trajectory smoothness, which can lead to paths that are difficult or unsafe to execute in real-world environments. To address these limitations, we propose $\Design$, a self-supervised pathfinding framework that jointly considers obstacle proximity and path smoothness. At its core, our novel Vision Kansformer module learns representations of obstacle distributions without relying on labeled trajectories, enabling the model to better adapt to complex environments. We further introduce a sharp-turn penalty to encourage smoother and more practically executable paths. Extensive experiments demonstrate that, compared with state-of-the-art (SOTA) approaches, $\Design$ achieves an average of 3.28% greater obstacle clearance and 87.07% lower inference latency while maintaining smooth path generation.
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Artificial Intelligence

A-CPES: A Reference Framework for Agentic AI in Cyber-Physical Energy Systems

Energy system operation contains a loop of work that automation has never taken over: posing the optimization problem the current cycle should solve, disposing of infeasibility, sequencing a solution into interlocked switching orders, assembling evidence no single model holds, negotiating adjustable capacity with many parties, and settling experience into practice. Licensed dispatchers carry all of it in person, and the rising share of variable renewable generation is making that loop turn faster than their number can grow. Agentic AI supplies the abilities it requires, but enters as the outer loop of control: it calls SCED and the other decision models rather than being called by them. We propose A-CPES, three nested rings, an authorization and accountability frame around an agentic control outer loop around a six-layer CPES core. We argue the loop is indivisible, tune where and how tightly it may close, state eight structural failure modes as falsifiable predictions, and specify six governance modules that rebuild the authorization frame until it covers the loop, before the loop starts turning.
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All authors Xiaoyu Zhang, Qiuye Sun, Jiachen Xu, Zhongming Yao, Yushuai Li

Robotics

Exact Finite-Length Theory of Uniform Car Parking: Spatial Laws, Absorption, and Aggregation

The uniform car-parking process is the one-dimensional random sequential adsorption of unit cars on a segment of finite length $s$: cars arrive at uniformly random positions and park wherever they fit, until no gap admits another. This paper develops the exact finite-$s$ theory. The joint density of the parked positions is resolved into jamming cells, on each of which it is a rational function, and evaluated by a subset recursion in $O(2^n n)$ operations; the marginal and gap order statistics are obtained as hyperlogarithms whose weight is fixed by the number of coordinates integrated out; and the absorption count and the aggregate quantities are treated through the integral equation descending from Rényi.
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Computer Vision

Hyperbolic Hierarchical Clustering for Visual Representation Learning

We investigate the token mixer in vision backbones by revisiting clustering, one of the most classic approaches in machine learning. An effective token mixer is a fundamental component of modern vision backbones like vision Transformers, facilitating information exchange between image patches. Mainstream token mixers, which rely on convolution, attention, MLP, or their hybrids, primarily focus on navigating the trade-off between accuracy and computational cost. However, a significant drawback of these methods is their black-box nature; their encoding process is opaque and lacks interpretability. Diverging from these opaque designs, we introduce ClusterMixer, a transparent token mixer that is grounded in a clustering paradigm and interpretable by design. ClusterMixer explicitly formulates the token mixing process through a hierarchical clustering mechanism. To model the natural, tree-like relationships inherent in visual data, the clustering is performed in hyperbolic space, which is well-suited for embedding hierarchies with low distortion. Building on this innovation, we present HCFormer, a new backbone architecture that integrates ClusterMixer with a series of meticulously designed clustering strategies to ensure robust performance across tasks. Extensive experiments demonstrate that HCFormer consistently outperforms its counterparts across diverse tasks, including image classification, object detection, instance segmentation, and semantic segmentation. Considering its transparency and efficacy, we hope HCFormer can facilitate a paradigm shift toward interpretable backbones.
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All authors Jianan Wei, Guikun Chen, Zhiyuan Weng, Chunchao Guo, Yujia Wang, Wenguan Wang

Sunday 23 August

Human-Computer Interaction

Can You Spot the Virtual Patient (VP)? Expert Evaluation, Turing Test, Linguistic Analysis, and Semantic Similarity Analysis

Communication is a core clinical competency and essential for safe, effective patient care. Virtual patients (VPs) powered by large language models (LLMs) offer a promising alternative to traditional formats such as standardized patients (SPs). However, few studies have quantitatively as well as qualitatively evaluated their realism across diverse clinical scenarios using behavioral studies and linguistic dialog analyses. This study evaluated the realism of GPT-4o-generated VPs through expert review, Turing testing, linguistic analysis, and semantic analysis. We generated 44 VPs using structured illness scripts derived from doctor-simulated patient dialogues across 17 clinical categories. Experts annotated responses for hallucinations, omissions, and repetitions, with high interrater reliability (ICC > 0.77). A Turing test revealed that participants struggled to distinguish VP responses from those of real patients, with average classification accuracy for VP responses falling below chance level. Lexical and syntactic analyses of over 2,000 conversation turns showed that VP responses were generally realistic, more formal and lexically consistent, while human responses displayed greater emotional variation. Semantic similarity using BioClinicalBERT and cosine similarity averaged 0.871 at the response level and 0.842 at the transcript level. Our findings support the integration of LLM-based VPs in communication training while highlighting areas for trust, transparency, and refinement, contributing to both GenAI deployment in healthcare and its safety evaluation.
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All authors Reyhaneh Hosseinpourkhoshkbari, Wei-chen Huang, Suvel Muttreja, Richard M. Golden

Human-Computer Interaction

Human-Likeness is Multi-Dimensional: Evaluating LLM Generated Virtual Patients Against Simulated Patient Dialogue

Large language models (LLMs) are increasingly used to generate virtual patients (VPs) for medical training. As these systems move toward broader deployment in medical education, reliable evaluation is needed to identify potential failure modes and ensure that generated patient responses remain consistent with human simulated patient (SP) behavior. Inaccurate, unrealistic, or inconsistent responses may introduce educational risks by exposing learners to misleading patient interactions. However, current evaluation approaches rely heavily on human judgment, making large-scale evaluation difficult. In this work, we present a controlled generation pipeline for systematically comparing VP responses generated by 10 LLMs across multiple decoding temperatures with human respiratory SP responses. To support scalable evaluation, we introduce a multi-dimensional framework for measuring similarity between LLM-generated and human SP dialogue across semantic, conversational grounding, linguistic, and emotional dimensions. Across semantic, conversational, linguistic, and emotional dimensions, no single model consistently produced the most human-like responses. From a practical perspective, Gemini 2.5 Flash demonstrated the most consistently human-like performance across semantic, linguistic, grammatical, and emotional dimensions, while Claude Sonnet 4.6 achieved the strongest semantic fidelity. These findings highlight the importance of multi-dimensional evaluation and demonstrate how automated metrics can provide a scalable approach for assessing virtual patient systems before broader deployment in medical education.
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All authors Reyhaneh Hosseinpourkhoshkbari, Wei-Chen Huang, Yile Wang, Alireza Irani Helabad, Zhiyu Chen, Richard M. Golden

Human-Computer Interaction

Cross-Modal Associations in Creativity: Evaluating Word-Image Pairing in Humans and Large Language Models

Given differences in the associative memory architectures of humans and AI, it is not clear whether AI generates and interprets visual-linguistic associations the way humans do. To investigate this, human participants and two large language models (LLMs), ChatGPT and Gemini, were asked to generate novel words and corresponding images that form meaningfully linked dyads. The LLMs and a second group of human participants were presented with shuffled sets of these words and images and asked to rematch them in ways they felt were most meaningful. Humans performed similarly regardless of whether the pairs were human or LLM-generated, while LLMs were better at matching LLM-generated pairs. Overall, LLMs outperformed humans at recovering the intended pairings. These findings suggest that despite architectural differences, the way in which AI generates and detects associations between language and visual stimuli is not only like that of hu-mans, but they may be superior at recognizing cross-domain associations that humans find meaningful.
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Machine Learning

Adaptive Depth Aggregation in Graph Transformers for Long-Range Graph Reasoning

Graph Transformers improve long-range node-to-node communication through global or structure-aware interactions. However, improving cross-node communication does not determine how computations produced at different depths should be combined. Standard residual streams accumulate successive computations with fixed unit coefficients shared across nodes. This fixed aggregation is a residual-interface constraint: once intermediate contributions have been produced, the interface cannot explicitly reweight them by node. We hypothesize that this constraint can create a depth-wise aggregation mismatch when the relative utility of these intermediate contributions varies across nodes and structural contexts. To study this hypothesis, we formalize Graph Transformer residual computation as a causal node-wise history of graph-propagation and feed-forward network (FFN) contributions, making depth aggregation an explicit interface choice. We realize node-adaptive aggregation over this history with Attention Residuals (AttnRes) while preserving the backbone's graph-propagation and auxiliary-state machinery. Block AttnRes reduces the routing cost of long histories relative to Full AttnRes by pooling consecutive contributions. We instantiate the interface in GPS and GRIT and evaluate it on all five ECHO tasks. Both variants achieve lower mean absolute error (MAE) than their independently tuned backbones on every task, and at least one obtains the lowest mean among all compared methods in each task. Routing-only donor-swap interventions support the mismatch hypothesis, while additional ablations examine the key design choices. Together, these results support node-adaptive depth aggregation as a useful complement to cross-node communication in long-range graph reasoning.
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Computation and Language

baseVultra: Compact Nonlinear Recurrence with Reallocated Capacity

Nonlinear recurrent networks remain useful for streaming sequence modeling, yet gated cell design is still dominated by LSTM and GRU. We study whether recurrent computation can be reallocated away from gate transforms and toward candidate generation. We propose baseVultra, a compact recurrent cell that concentrates the dense recurrent budget on a single H x H candidate-generation matrix, while replacing recurrent gate matrices with O(H) diagonal interactions. The candidate update combines this dense branch with two low-rank auxiliary branches, an EMA cache, and learnable output blending; the gates additionally receive lightweight second-order access to h_{t-2} through diagonal terms. On TinyShakespeare character-level language modeling, baseVultra achieves a validation loss of 1.594 in the compact one-layer 200K setting, compared with 1.604 for a parameter-matched LSTM and 1.616 for a parameter-matched GRU, while its dense recurrent matrix-vector computation is about 54% of GRU under matched hidden size for this configuration. On text8, a roughly 45x larger benchmark, baseVultra is competitive with full-gate cells (1.854 bpc vs. 1.849 for GRU and 1.837 for LSTM). On formal-language probes, the largest gains appear under constrained hidden-state capacity (0.991 vs. 0.761 GRU and 0.691 LSTM OOD2 accuracy on Counter at H=16) and vanish as hidden size grows. These results characterize where and when candidate-focused recurrent capacity allocation helps: the benefit is concentrated in compact regimes, while full-gate cells remain competitive at scale.
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Machine Learning

Linear RNN Scaling Laws: When Longer Sequences Beat More Sequences

Empirical scaling laws for autoregressive language models relate prediction loss to model size, data size, and optimization compute, but their theoretical origin is still poorly understood in sequential pretraining settings. We study this question in a tractable teacher–student model where a stable latent linear RNN generates trajectories and a sketched linear recurrent student is trained by safeguarded full-batch WSD gradient descent on next-token prediction. The sketch dimension $M$ plays the role of model size, while $N$ independent trajectories of length $P$ provide the training tokens. We allow the innovation and initialization covariances to have different power-law exponents $\alpha$ and $\theta$. The induced design spectrum produces explicit approximation, optimization, and statistical scaling laws separated by spectral crossovers. When $\theta\ge\alpha$, the original one-scale rates $M^{1-\beta_\alpha}$, $R^{(1-\beta_\alpha)/\alpha}$, and $(NP)^{-1}\min\{M,R^{1/\alpha}\}$ are recovered. When $\alpha-2r\le\theta<\alpha$, the heavier initialization tail changes the rates beyond $P$-dependent model and optimization crossovers. The proof uses a covariance event only internally and a globally safeguarded step size on its complement. The variance retains the factor $(NP)^{-1}$, while sequence length also suppresses the initialization transient, so $N$ and $P$ cease to be fully interchangeable in the two-scale regime.
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All authors Ziyan Chen, Zhongzhu Zhou, Linhe Zheng, Peilin Liu, Ding-Xuan Zhou

Machine Learning

I-SplineFlow: Learning Monotone Spline Stochastic Interpolant Schedulers for Few-Step Generation

Few-step generation with pretrained diffusion and flow models can be accelerated by lightweight training that optimizes the sampling trajectory rather than the network. A recent approach parameterizes the stochastic interpolant (SI) scheduler as a smooth curve whose control points enforce the three properties an SI scheduler must satisfy: fixed boundary conditions, a monotone signal-to-noise ratio (SNR), and differentiability. Existing parameterizations use globally supported polynomial bases, where every control point moves the whole curve and higher expressiveness needs a higher degree, which couples distant regions of the schedule during optimization. We introduce I-SplineFlow, which parameterizes the scheduler with integrated monotone splines (I-splines). I-splines decouple the polynomial degree from the number of mixture weights, so support width and smoothness can be chosen per model at a fixed weight count, and the compactly supported derivative basis makes the scheduler Jacobian orders of magnitude better conditioned than a Bézier basis. Boundary conditions and a strictly monotone SNR hold by construction, with no ordering constraint on the parameters and closed-form velocity derivatives. Across diffusion (EDM) and flow (ReFlow, Simple ReFlow) models, I-SplineFlow improves few-step FID over Bézier scheduling in most settings, most clearly at the lowest NFEs, and trains in minutes. Ablations show that both the degree freedom and the monotonicity constraint are needed. The code will be released upon acceptance.
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All authors Md Sakib Hossain Shovon, Md Rifat Ur Rahman, Md Abtahi Majeed Chowdhury, Yunhong Min, Jaesik Choi, Minhyuk Sung

Computer Vision · Cross-listed from eess.IV

Local SVD-Entropy Maps as a Complementary Structural Representation for Full-Reference and No-Reference Image Quality Assessment

We investigate a local spectral-complexity representation for perceptual image quality assessment (IQA) based on Shannon entropy of singular values computed directly from two-dimensional image patches. For each $3\times3$-pixel grayscale patch, SVD is applied directly and the normalized singular-value entropy defines one HSVD-map value. The construction requires neither flattening nor delay embedding, uses no boundary padding, and is invariant to $90^{\circ}$ rotations and mirror reflections at the local-descriptor level. A nested salt-and-pepper experiment on Lena separates absolute similarity to a clean reference from sensitivity to an additional degradation step. HSVD-SSIM responds more strongly to local corruption and retains a larger neighboring-state response at severe noise levels. Validation on all 10,125 distorted KADID-10k images shows that HSVD-SSIM is weaker than conventional SSIM as a standalone full-reference metric (SRCC $0.450$ vs. $0.619$), but complementary when combined with it: grouped cross-validation increases SRCC from $0.618$ to $0.659$, with a bootstrap 95% confidence interval of $[0.036,0.046]$ for the gain. In a no-reference experiment, adding HSVD-derived single-image descriptors improves the best nonlinear model from SRCC $0.528$ to $0.575$ (95% CI $[0.033,0.061]$) and also improves prediction of quality changes between neighboring distortion states. These results support direct local SVD entropy as an interpretable structural channel that complements conventional image-domain similarity and remains informative without a pristine reference.
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Machine Learning

CS-WCP: Robust Conformal Sets for LLM-Judge Traffic Shifts with Uncertain Group Proportions

Prediction sets built from an LLM judge can undercover when deployment traffic changes the prevalence of task or policy groups. Weighted conformal prediction is exact under covariate shift when the density ratio is known, but group proportions must usually be estimated from finite unlabeled samples. We introduce confidence-set weighted conformal prediction (CS-WCP), which constructs simultaneous exact intervals for source and target group masses and returns the union of weighted conformal sets over every compatible ratio vector. For a fixed or independently learned finite partition, CS-WCP attains coverage at least 1-alpha-delta_w-tau_A-kappa, where tau_A measures within-cell covariate mismatch and kappa measures conditional shift. A linear endpoint rule computes the robust union in O(G|Y|) time. Across 336 constructed shared-support traffic shifts, CS-WCP reaches 0.973 mean coverage with 13 point failures, compared with 0.954 and 44 failures for source conformal prediction, at mean binary set sizes 1.74 and 1.65. On 336 natural cross-task transfers, coverage rises from 0.882 to 0.962, but mean set size reaches 1.87 and a size-matched group plug-in baseline is competitive. The method therefore supplies an auditable coverage safeguard under uncertain mixture weights; its value is conservative tail protection, not scalar probability calibration or uniformly smaller sets.
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Machine Learning

When Accuracy Gaps Fail to Certify: Auditing Cross-Domain Recalibration of LLM Judges

A scalar recalibration map fitted for an LLM judge on one task can fail when the task distribution changes, but the source-target accuracy gap is often treated as a proxy for that failure. We test what this gap can predict and what it can certify across thirteen judges, two generators, eight domains, and 1,176 predeclared transfers. After accounting for mean score shift, the gap yields a population lower bound on target calibration error, yet identical gaps can induce opposite transfer outcomes. Exact importance weighting recovers target proper loss under covariate shift, so failure of an estimated weighting pipeline does not by itself establish conditional shift. A finite-sample simultaneous lower certificate converts the population bound into a one-sided rejection rule using audit labels disjoint from evaluation outcomes. The leak-free gap correlation is 0.25 (95% CI [-0.09, 0.55]), falls to 0.09 on the second generator, and does not support a generator-invariant association. The certificate retains nominal coverage but has power 0.13 even at m=1024, whereas target-domain temperature scaling with 16 labels reaches harm rate 0.09, compared with 0.34 for source-fitted Platt scaling. Accuracy gaps are therefore weak warning signals for scalar probability transfer, not deployment certificates.
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Computational Complexity · Cross-listed from math.CO

Blocky Matrices and Group Idempotents

We prove a common generalization of two structure theorems: the dimension-free decomposition theorem for idempotent Schur multipliers and the idempotent theorem in harmonic analysis. Roughly speaking, our result shows that an invariant integer-valued kernel with Hilbert-space factorization norm $\gamma$ admits a signed decomposition into at most $2^{O(\gamma^4)}$ elementary pieces. In the matrix setting these pieces are blocky matrices, while in the group setting they are indicators of cosets. In the locally compact abelian setting this quantitatively strengthens the theorem of Green and Sanders, while in the non-abelian setting it gives a quantitative strengthening of Host's idempotent theorem and, for finite groups, of Sanders's quantitative result. It also improves the exponent in the dimension-free matrix decomposition from $\gamma^6$ to $\gamma^4$.
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Cryptography and Security

Enhancing Multiclass Malware Classification in Resource-Constrained Environments

The emergence of multi-class malware attacks such as ransomware, spyware, trojans, etc., presents an increasing and serious threat to cybersecurity, particularly in resourceconstrained environments like IoT devices. Existing machine learning models have achieved nearly perfect accuracy in binary malware classification but fall short in terms of classifying malware families and individual malware. Additionally, the complexity of these multi-class malware attacks presents a significant challenge of detection in resource-constrained environments, as multi-class detection usually requires high computational capability. This research bridges the gap by enhancing the detection accuracy of multi-class malware classification as well as developing a lightweight model that can run efficiently on resource-constrained devices. In this paper, we propose a robust, lightweight machine learning model featuring LightGBM classifier with SMOTE oversampling and SOM-US undersampling techniques for data balancing, as well as well-engineered feature selection through Genetic Algorithm. The model performed better than the current state-of-the-art models developed on the same dataset in both malware family classification (4 classes) and individual malware type classification (16 classes) with accuracy of 89.1% and 76% respectively. Thus, maintaining a balance between classification accuracy and computational efficiency in resource-constrained environments. Furthermore, we propose another model using Random Forest classifier with an accuracy of 91.2% in malware family classification and 78.7% in individual malware classification. Demonstrating a significant enhancement in terms of accuracy from the current state-of-the-art models.
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All authors Abdul Khalek Alve, Alif Rahman, Saadman Zaman, Sazzad Hossen Himel, Muhammad Iqbal Hossain

Social and Information Networks

The Emergence of Causal Curiosity from Prior Causal Belief Networks

Causal curiosity is foundational to human cognition. It is the desire to understand why events happen, what mechanisms underlie them, and how outcomes can be explained or anticipated. It motivates exploration, sustains attention, and fuels the search for new knowledge. However, despite consensus on the importance of causal curiosity, little is known about how causal curiosity arises from existing belief systems. In our work, we examine how causal curiosity emerges from prior knowledge structures. With Reddit data from 2020 to 2023, and leveraging language models to extract cause-and-effect relationship pairs and identify causal curiosity-driven questions, our findings reveal that causal curiosity is not random or independent, but largely rooted in prior knowledge structure. Particularly, positive nouns are more likely to be the object of causal curiosity. Moreover, our findings indicate that concepts that serve more as causes are more likely to appear in causal curiosity than those that serve more as effects. Lastly, our results also suggest that causal curiosity emerges from the central of the prior belief network. These novel insights reveal that causal curiosity is not random but systematically grounded in prior knowledge structures, and suggest their implication to facilitate the human learning process by motivating people to actively explore and construct deeper understandings rather than passively receiving information.
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All authors Zhuoyu Shi, Xintong Jiang, Bohan Jiang, Fred Morstatter

Computation and Language

From Sentiment Classification to Actionable and Responsible Feedback: A Scoping Review and Evidence Map of NLP in Student Evaluation of Teaching, 2015-2026

Natural language processing (NLP) applied to open-ended teaching-evaluation comments (Student Evaluation of Teaching, SET) has tracked the field's technical evolution–from lexicons and conventional classifiers to transformers and large language models (LLMs)–but it is not evident that this technical diversification has been accompanied by corresponding gains in educational value and robustness of the evidence. This scoping review (PRISMA-ScR) maps 421 studies (2015-2026, 2026 partial) along a technical axis (RQ1) and four value dimensions (RQ2-RQ5). Dual mutually blinded LLM screening with sampled human adjudication coded seven extraction domains, with targeted codebook-boundary review at synthesis. The joint map's sharpest quantified gap is the actionability discontinuity: demonstrated output or stronger (A2+: 258/421; 61.3%) versus intended-user evaluation or stronger (A3+: 49/421; 11.6%), a 49.7 percentage-point drop. Sentiment analysis remains the modal task (300/421); diagnostic and generative depth is a substantial minority (D4-D5: 28.2% of resolved cases); a formal fairness metric is rare (1.9%). The findings are descriptive and do not support causal claims of progress: technological coexistence and uneven reporting are part of the map, but the A2+ to A3+ cliff is the contribution, not a quality ladder.
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Performance

The Joule Point: an Energy-Optimal Operating Point for AI Inference

Data centers serving AI inference strive to maximize GPU utilization, running their cards at full power by default: this maximizes throughput and holds latencies down, but it is energy-inefficient, spending more energy per inference than the same work needs at a better operating point. That inefficiency is a scheduling choice, not a hardware limit. The cause is physical: for a given workload, a GPU's board power rises superlinearly along its power-performance curve, on top of a fixed power floor that is paid for as long as the job runs, so energy per inference is U-shaped in the operating point (GPU, power cap). The minimum, which we name the Joule Point, is a cap at 43 to 46 per cent of a large GPU's rated power; capping to it cuts energy per inference by roughly a quarter to a third at a modest cost in capital and latency: each request runs about 1.2 times slower, and holding aggregate throughput takes that same factor more cards. Under load, the Joule Point is nearly a per-card-type constant, so a single static cap per card type captures nearly all the saving (mean penalty under one per cent), turning the online per-job search that prior systems run into a one-time characterization. We ground this in ELF, a dense power-cap dataset that sweeps 20 inference models across four GPUs; replaying it in a fleet simulation under a power budget, capping each job to the least power meeting its deadline spends 18 to 45 per cent less energy per served job. These results recast data-center energy as a schedulable resource an operator can adapt to a budget, an electricity price, or a carbon signal while meeting its service targets.
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Machine Learning

Block-Level Weight-Space Structure Persists Under Post-Training: An Empirical Study Across LLM Families

Modern LLMs are deployed as families of post-trained variants (base, instruct, chat, code) derived from a shared set of pre-trained weights. We present an empirical study of how post-training transforms weight-space geometry, covering eight configurations across four architecture families (Qwen2.5, Llama-3.1/3.2, Mistral, Gemma-2). We identify a granularity gap: post-training modifies every tensor (zero of 291-339 tensors remain byte-identical, so hash-based deduplication achieves 0% savings), yet preserves block-level structure (mean cosine similarity exceeds 0.99 and relative Frobenius distance stays below 0.13). Post-training therefore acts as a structured perturbation that shifts every parameter while leaving block-level geometry intact. The property is not universal: independently trained specializations (for example, Qwen2.5-Coder) attain cosine similarity around 0.64 with the general base, indicating a disconnected region of weight space. Perturbation magnitude varies systematically with model scale, architecture family, and post-training recipe. As a practical application, we build LinkerLLM, a lazy loader that aliases shareable blocks across co-resident variants, achieving 18-48% GPU memory savings and enabling up to five 7B-parameter variants on a single 24 GB consumer GPU. Five of eight configurations retain at least 94% of the unshared variant's quality on MMLU, ARC-Challenge, HellaSwag, and WinoGrande; the remaining three (Mistral-7B, Gemma-2-2B, Llama-3.2-1B) have one below-threshold benchmark each (87-91%), which we report transparently rather than gate the block-sharing decision on a single threshold.
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Computation and Language

Correlation-Aware Structured Pruning for Large Language Models

Structured pruning is a promising approach for reducing the substantial inference costs of Large Language Models (LLMs) while maintaining hardware efficiency. Many existing methods assess the importance of prunable units (e.g., channels or heads) in isolation, implicitly assuming that pruning errors are additive. This independence assumption is often invalidated by the non-orthogonality of model weights and strong correlations between unit activations, potentially leading to performance degradation. To address this, we propose a Correlation-Aware Structured Pruning method. We formulate the pruning objective as a cardinality-constrained binary quadratic program that explicitly models cross-unit dependencies in the reconstruction error. Since this binary quadratic program is NP-hard and difficult to solve exactly, we develop a greedy interaction algorithm based on dependency-aware marginal costs to optimize unit selection. Furthermore, we incorporate a gradient-based strategy to achieve adaptive layer-wise sparsity allocation across the entire model. Extensive experiments on mainstream LLMs demonstrate that incorporating correlation information yields competitive accuracy-efficiency trade-offs compared to representative structured pruning baselines.
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All authors Sicheng Xu, Hao Shi, Wei Zhang, Haoran Pang, Zhenyu Ming, Hao Wu, Zhongyi Huang, Xin Yao, Gong Zhang

Machine Learning

Hierarchical Bayesian optimization of an aircraft-based multi-agent system-of-systems

Developing innovative system architectures increasingly relies on advanced modeling and optimization techniques to frame the architecting process and define the corresponding computational problems. For complex System-of-Systems (SoS), high-fidelity multiphysics and multidisciplinary simulations are essential for capturing detailed behaviors. However, their computational expense and the risk of evaluation failures make direct optimization challenging. To overcome these limitations, surrogate-based approaches, like Bayesian optimization, have emerged as effective tools for managing expensive, black-box simulation tasks. This work introduces a hierarchical Bayesian optimization framework that leverages Gaussian process meta-modeling to handle discrete architectural choices, conditional dependencies, and heterogeneous design variables inherent to SoS problems. Results show that the hierarchical formulation improves search efficiency and robustness compared to conventional surrogate-based methods, enabling the exploration of large and structurally diverse design spaces with limited simulation budgets. We apply the approach to an aircraft-based multi-agent system for wildfire suppression, a use case developed within the EU-funded COLOSSUS project that illustrates how SoS principles can coordinate heterogeneous aerial platforms with complementary roles, supporting both sustainable mobility and emergency response missions. Our framework provides a scalable methodology for SoS architecting and model exploration, offering transferable insights for applications in aviation, sustainable mobility, and resilience-oriented system design. By combining hierarchical representations with surrogate-based optimization, this work is among the first practical demonstrations of hierarchical Bayesian optimization applied to real-world SoS problems, advancing both methodology and practice.
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All authors Paul Saves, Thierry Lefebvre, Nathalie Bartoli, Jasper Bussemaker, Nikolaos Kalliatakis, Nabih Naeem, Prajwal Prakasha

Machine Learning

Helix-FNO: Spectral-Domain Operator Learning Coupled with a High-Fidelity Mechanistic Model for Fast Surrogate Simulation

Mechanistic simulation models of full-scale treatment processes remain the only trustworthy, extrapolative description of the underlying physico-chemical dynamics, yet their runtime is far too slow to support the thousands of forward evaluations that a modern decision engine requires at a 5-minute decision cadence. The standard remedy-surrogate modelling-often produces a network that learns a single solution for a single configuration, so it generalises poorly to new influent profiles, control settings or plant layouts. This paper presents Helix-FNO, a teacher-student architecture that couples a thirty-two-state mechanistic teacher with a Fourier neural operator (FNO) student. The teacher supplies a high-fidelity dataset of input-field-to-solution pairs, curated by Latin-hypercube and uncertainty-based active learning to cover the boundary and overload regimes that matter in practice; the student learns, in the spectral domain, the solution operator itself rather than any single solution, thereby moving from learning one instance to learning an entire family of equations. We give the operator formulation, the spectral convolution definition, the weighted distillation loss and the active-learning criterion, and we analyse the approximation error of a truncated Fourier expansion with respect to the smoothness of the parametric solution manifold. An illustrative study compares Helix-FNO against a physics-informed network and a data-driven recurrent surrogate on accuracy, dataset efficiency and inference latency, and places the methods on a speed-accuracy Pareto front. The resulting operator is three orders of magnitude faster than the mechanistic teacher at millisecond inference, which is precisely the capability required for massive candidate screening and online decision support.
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