arXiv Machine Learning

Does Text Steer Neural PDE Surrogates? A Controlled Diagnostic with OperatorCLIP

The study investigates whether text conditioning improves neural partial differential equation (PDE) surrogates by using OperatorCLIP. Experiments compare an unconditioned Fourier Neural Operator (FNO), a constant-sentence FiLM control, and a task‑specific text description trained with contrastive alignment across Darcy2D, ShallowWater2D, and 3D compressible Navier‑Stokes. Results show that constant conditioning yields lower mean test error on 2D tasks, while task text plus alignment performs similarly or worse, with significant seed uncertainty and no clear semantic ordering from prompt interventions.

arXiv AI
Sep 17

From Alignment to Synthesis: Contrastive Volumetric Grounding for Text-to-CT Generation

The paper introduces a 3D-CLIP encoder trained with structured hard negatives to improve vision‑language alignment for text‑to‑CT generation. This encoder drives a latent diffusion model that operates directly in 3D latent space, eliminating spatial artifacts from super‑resolution pipelines. Experiments on the CT‑RATE dataset show state‑of‑the‑art image fidelity and factual correctness across 18 pathological conditions, with lower inference time and GPU memory usage than competing methods.

By Daniele Molino, Camillo Maria Caruso, Filippo Ruffini, Paolo Soda, Valerio Guarrasi
arXiv AI
Jun 24

When Language Overwrites Vision: Over-Alignment and Geometric Debiasing in Vision-Language Models

arXiv:2605. 08245v4 Announce Type: replace-cross Abstract: Vision-Language Models (VLMs) increasingly power high-stakes applications, from medical imaging to autonomous systems, yet they routinely hallucinate, confidently describing content not present in the input.

By Harshvardhan Saini, Samyak Jha, Yiming Tang, Dianbo Liu
arXiv AI
Oct 15

Visual Dependence Does Not Imply Answerability: A Systematic Analysis of Answerability Signals in Frozen InstructBLIP

The study evaluates whether signals from a frozen vision‑language model, InstructBLIP, can reliably indicate answerability in visual question answering. Using a 10K subset of UNK‑VQA, the authors test predictive uncertainty, cross‑modal alignment, visual grounding, visual dependence, internal representations, and learned probes, finding that all signals yield weak discrimination (AUROC 0.50‑0.54). Even interventions that remove question‑relevant visual evidence or increase probe capacity do not substantially improve answerability detection, underscoring that visual dependence and related metrics are not robust proxies for answerability.

By Minjun Kim, Hyunmin Song, Changwon Lim
arXiv AI
Oct 12

Teaching neural decoders with language

The paper introduces Language as Supervision (LaS), a method that aligns neural activity with natural‑language class descriptions via learned projections and uses candidate text prototypes for classification. Evaluated across seven encoder architectures on visual, motor, and speech decoding tasks from scalp and intracranial recordings, LaS boosts speech‑decoding accuracy by up to 17.15 percentage points compared to traditional class‑label supervision. The approach also enables reusable candidate sets, subject‑ and session‑adaptation, and conditional unseen‑frequency decoding in steady‑state visual evoked potentials, with dual‑sided attribution visualizations highlighting both neural and textual contributions to class matching.

By Xuan Wen, Yonghao Song, Yuhong Zhang, Guoliang Li, Tzyy-Ping Jung, Xiaorong Gao
arXiv AI
Aug 19

Where a New Concept Must Enter: Entry Point Gates Cross-Task Usability in Unified Multimodal Models

The paper investigates how new concepts can be integrated into unified multimodal models (UMMs) by separating generation and understanding objectives through a novel visual entity bound to a single task direction. Experiments show that the effectiveness of cross‑task usability depends on where the concept is injected into the shared computation, with a mid‑stack alignment objective achieving high concept acquisition with minimal loss to overall performance. The study highlights that unified weights alone are insufficient; the two directions must share a semantic format at the entry point for efficient concept integration.

By Zongyang Qiu, Yihan Wu, Kaixuan Fan, Bo Li, Hui Xiong
Hugging Face Trending Papers
Sep 24

Reasoning Instructions Can Break Answer Decoding in Vision--Language Models

The paper shows that chain‑of‑thought (CoT) instructions can distort multiple‑choice vision‑language model evaluation when a scorer appends a reasoning cue but reads answer‑label logits before the model generates any rationale. This CoT‑prefix scoring causes significant drops in accuracy (e.g., Qwen2.5‑VL‑7B falls from 80.76% to 45.48% on ScienceQA) and leads most predictions to choose the first option. Analysis reveals that while answer information remains linearly accessible in late layers, the immediate readout is misled by probability mass shifting toward continuation tokens, and the issue varies across datasets and models.

arXiv Computation and Language
Oct 1

MetaSteer: Context-Conditioned, nonlinear Steering via Attention-Projection Adaptation

MetaSteer is a new method for steering large language models that learns nonlinear, context-dependent interventions applied to attention projection matrices. Unlike traditional linear, context-independent techniques, MetaSteer adapts its effects based on the input, requiring no linear concept-geometry assumption. Trained once on a pooled preference corpus, it transfers zero‑shot to unseen concepts and out‑of‑distribution contexts, matching or surpassing strong task‑specific baselines on multiple benchmarks and model families.

By Mehdi Jafari, Hao Xue, Flora Salim
arXiv Machine Learning
Oct 16

Where to Steer: Input-Dependent Layer Selection for Steering Improves LLM Alignment

The paper introduces Where to Steer (W2S), a framework that adaptively selects which layer of a large language model to intervene on based on the input. It argues that optimal steering layers vary across inputs and demonstrates that W2S outperforms fixed-layer steering methods on several LLMs and alignment tasks, both in‑distribution and out‑of‑distribution. The study highlights input‑dependent layer selection as a complementary design dimension to steering vector extraction.

By Soham Gadgil, Chris Lin, Su-In Lee
arXiv Computation and Language
Oct 26

Semantically Rich, Metrically Affect-Blind: A Geometric Blind Spot in Modern Text Embedders

The paper uncovers a systematic mismatch in modern text embeddings: while sentiment can be extracted with high accuracy from frozen encoders, the embeddings’ cosine similarity metric barely reflects polarity differences. Across eleven models from 2021–2026, a linear probe achieves up to 91.3% accuracy, yet cosine similarity margins are only 0.003–0.064, leading to poor retrieval performance (e.g., Qwen3-Embedding-4B’s 64.3 MAP). Introducing a lightweight supervised‑contrastive head (Sentiment‑Injected Sentence Embeddings) dramatically improves probe accuracy, retrieval MAP, and polarity margins, but at the cost of downstream semantic similarity. "whyItMatters":"The findings reveal that widely used retrieval and clustering systems may ignore valuable sentiment information encoded in embeddings, impacting their effectiveness."

By Mahdi Naser Moghadasi