arXiv subjects

Keisuke Matsuda

Publications and source records attributed to Keisuke Matsuda.

5 recordsLinked to original sources

arXiv2026

Taming Visual Neglect: A Variational Information Bottleneck Framework for Adaptive Attention in Multimodal In-Context Learning

Large vision-language models exhibit strong in-context learning (ICL) capabilities, yet when and why visual context helps multimodal ICL remains poorly understood. Empirical studies show a puzzling dichotomy: models sometimes effectively leverage visual demonstrations, yet often neglect them entirely. We propose VIB-ICL, an information-theoretic framework that resolves this dichotomy through the Information Bottleneck principle. We introduce the Cross-Modal Information Gain (CMIG), which quantifies the additional mutual information that visual context provides about the target beyond textual context. We derive a generalization bound showing that multimodal ICL's excess risk over text-only ICL is governed by the CMIG, proving that multimodal ICL provably outperforms text-only ICL when visual information is non-redundant. We further prove that visual context neglect, often viewed as a failure mode, is the Information Bottleneck-optimal solution when visual information is redundant, yielding a closed-form Attention Reallocation Principle that prescribes how visual attention weights should be adaptively adjusted. We instantiate this principle in the VIB-ICL algorithm, which estimates CMIG via variational bounds and dynamically reallocates attention. Experiments on five benchmarks demonstrate consistent improvements of up to 4.7\% accuracy gains and 35\% reduction in required demonstrations, validating our theoretical predictions.

cs.CL↗

arXiv2026

AE-LLM: Adaptive Efficiency Optimization for Large Language Models

Large Language Models (LLMs) have achieved remarkable success across diverse applications, yet their deployment remains challenging due to substantial computational costs, memory requirements, and energy consumption. Recent empirical studies have demonstrated that no single efficiency technique is universally optimal; instead, the effectiveness of methods such as efficient attention mechanisms, mixture-of-experts (MoE), parameter-efficient fine-tuning, and quantization varies significantly depending on task characteristics, resource constraints, and model scales. Building upon these insights, we propose AE-LLM, a unified framework that automatically selects and combines optimal efficiency techniques tailored to specific deployment scenarios. Our approach introduces a multi-objective optimization framework that jointly considers accuracy, latency, memory footprint, and energy consumption, while accounting for hardware constraints and task requirements. We develop an efficient search algorithm that explores the combinatorial space of efficiency techniques across architecture, fine-tuning, and inference stages, identifying Pareto-optimal configurations. Extensive experiments across 15 models (0.5B-70B parameters) and 10 diverse tasks demonstrate that AE-LLM achieves an average of $2.8\times$ improvement in efficiency metrics while maintaining competitive accuracy (within 1.2\% of baseline), compared to static efficiency configurations. Furthermore, our framework generalizes effectively to vision-language models, achieving similar efficiency gains. Our contributions provide practitioners with an automated tool for navigating the complex trade-off landscape of LLM efficiency optimization.

cs.LG↗

arXiv2026

Contextual Discrepancy-Aware Contrastive Learning for Robust Medical Time Series Diagnosis in Small-Sample Scenarios

Medical time series data, such as EEG and ECG, are vital for diagnosing neurological and cardiovascular diseases. However, their precise interpretation faces significant challenges due to high annotation costs, leading to data scarcity, and the limitations of traditional contrastive learning in capturing complex temporal patterns. To address these issues, we propose CoDAC (Contextual Discrepancy-Aware Contrastive learning), a novel framework that enhances diagnostic accuracy and generalization, particularly in small-sample settings. CoDAC leverages external healthy data and introduces a Contextual Discrepancy Estimator (CDE), built upon a Transformer-based Autoencoder, to precisely quantify abnormal signals through context-aware anomaly scores. These scores dynamically inform a Dynamic Multi-views Contrastive Framework (DMCF), which adaptively weights different temporal views to focus contrastive learning on diagnostically relevant, discrepant regions. Our encoder combines dilated convolutions with multi-head attention for robust feature extraction. Comprehensive experiments on Alzheimer's Disease EEG, Parkinson's Disease EEG, and Myocardial Infarction ECG datasets demonstrate CoDAC's superior performance across all metrics, consistently outperforming state-of-the-art baselines, especially under low label availability. Ablation studies further validate the critical contributions of CDE and DMCF. CoDAC offers a robust and interpretable solution for medical time series diagnosis, effectively mitigating data scarcity challenges.

cs.LG↗

arXiv2025

XDR-LVLM: An Explainable Vision-Language Large Model for Diabetic Retinopathy Diagnosis

Diabetic Retinopathy (DR) is a major cause of global blindness, necessitating early and accurate diagnosis. While deep learning models have shown promise in DR detection, their black-box nature often hinders clinical adoption due to a lack of transparency and interpretability. To address this, we propose XDR-LVLM (eXplainable Diabetic Retinopathy Diagnosis with LVLM), a novel framework that leverages Vision-Language Large Models (LVLMs) for high-precision DR diagnosis coupled with natural language-based explanations. XDR-LVLM integrates a specialized Medical Vision Encoder, an LVLM Core, and employs Multi-task Prompt Engineering and Multi-stage Fine-tuning to deeply understand pathological features within fundus images and generate comprehensive diagnostic reports. These reports explicitly include DR severity grading, identification of key pathological concepts (e.g., hemorrhages, exudates, microaneurysms), and detailed explanations linking observed features to the diagnosis. Extensive experiments on the Diabetic Retinopathy (DDR) dataset demonstrate that XDR-LVLM achieves state-of-the-art performance, with a Balanced Accuracy of 84.55% and an F1 Score of 79.92% for disease diagnosis, and superior results for concept detection (77.95% BACC, 66.88% F1). Furthermore, human evaluations confirm the high fluency, accuracy, and clinical utility of the generated explanations, showcasing XDR-LVLM's ability to bridge the gap between automated diagnosis and clinical needs by providing robust and interpretable insights.

cs.CV↗

arXiv2006

Spin Singlet State in Heptamers Emerging in Spinel Oxide AlV$_2$O$_4$

We present our theoretical results on the electronic state in vanadium spinel oxide AlV$_2$O$_4$. The material is a mixed-valent system with the average valence V$^{2.5+}$, and V cations constitute a frustrated pyrochlore structure. It shows a structural transition at $\sim 700$ K, leading to the formation of seven V-sites clusters -- heptamers. We study the electronic state of the heptamer by explicitly taking account of orbital degree of freedom as well as electron correlations. We show that the ground state of the heptamer for realistic parameters becomes spin-singlet because of strong $σ$-type bonding states of $t_{2g}$ orbitals. The temperature dependence of the magnetic susceptibility in experiments is naturally understood by this singlet formation in heptamers. Our results indicate that in AlV$_2$O$_4$ orbital physics is relevant to stabilize a cluster-type singlet state instead of a previously proposed charge-ordered state with valence skipping.

cond-mat.str-el↗