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NatWest Bank

Industry researcheurope · gb
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Research library14linked papers
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Selected work

Representative Papers

GNN-based Multi-Agent Control of Traffic Shockwaves in Sparse Vehicular Ad-hoc Networks

Jul 26, 2026

This study addresses the challenges posed by traffic shockwaves, which exacerbate congestion, reduce fuel efficiency, and elevate accident risks. Existing control strategies often rely on global traffic information, limiting their applicability in sparse vehicular ad hoc networks (VANETs). To overcome this limitation, this work proposes a decentralized cooperative control framework that integrates graph neural networks (GNNs) with multi-agent reinforcement learning (MARL), enabling connected automated vehicles to effectively suppress shockwave propagation using only local observations and interactions with neighboring vehicles. Notably, this approach is the first to incorporate GNNs into MARL under sparse VANET conditions, substantially enhancing practicality for early-stage deployment. Simulation results on a highway scenario with only 10% market penetration demonstrate up to an 80% reduction in shockwave propagation, confirming the method’s efficacy and scalability.

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Dr. SHAP-AV: Decoding Relative Modality Contributions via Shapley Attribution in Audio-Visual Speech Recognition

Mar 12, 2026

This work addresses the unclear dynamics of how audio-visual speech recognition (AVSR) systems weigh contributions from audio and visual modalities under noisy conditions. The authors propose Dr. SHAP-AV, a novel framework that introduces Shapley values into AVSR for the first time, quantifying modality contributions across three dimensions: global importance, generation process, and temporal alignment. Their analysis reveals that AVSR models remain significantly reliant on audio even at low signal-to-noise ratios (SNR), that modality weights are primarily governed by SNR and evolve dynamically during decoding, and that temporal alignment mechanisms exhibit robustness in noisy environments. Extensive experiments across two benchmarks and six state-of-the-art models validate the effectiveness of Dr. SHAP-AV, offering a new tool for interpretability and diagnostic analysis in AVSR research.

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Evaluating Performance Drift from Model Switching in Multi-Turn LLM Systems

Mar 03, 2026

This study addresses the performance degradation caused by context mismatch when switching large language models (LLMs) in multi-turn dialogues—a phenomenon termed "silent drift." The work presents the first systematic characterization of this issue and introduces a benchmark evaluation framework based on a switching matrix. By employing pairwise turn-level bootstrap confidence intervals, the authors quantify the impact of model switching on dialogue performance across datasets such as CoQA and Multi-IF. A key innovation lies in decomposing the drift into prefix influence and suffix sensitivity, revealing systematic robustness or vulnerability of models to non-self-generated context. Experiments demonstrate that a single switch can alter Multi-IF’s strict success rate by −8 to +13 percentage points and induce CoQA F1 fluctuations of up to ±4 points, offering both theoretical insights and practical tools for effective risk monitoring.

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Recent publications

Latest Papers

GNN-based Multi-Agent Control of Traffic Shockwaves in Sparse Vehicular Ad-hoc Networks

Jul 26, 2026

This study addresses the challenges posed by traffic shockwaves, which exacerbate congestion, reduce fuel efficiency, and elevate accident risks. Existing control strategies often rely on global traffic information, limiting their applicability in sparse vehicular ad hoc networks (VANETs). To overcome this limitation, this work proposes a decentralized cooperative control framework that integrates graph neural networks (GNNs) with multi-agent reinforcement learning (MARL), enabling connected automated vehicles to effectively suppress shockwave propagation using only local observations and interactions with neighboring vehicles. Notably, this approach is the first to incorporate GNNs into MARL under sparse VANET conditions, substantially enhancing practicality for early-stage deployment. Simulation results on a highway scenario with only 10% market penetration demonstrate up to an 80% reduction in shockwave propagation, confirming the method’s efficacy and scalability.

0 citationsRead paper

Dr. SHAP-AV: Decoding Relative Modality Contributions via Shapley Attribution in Audio-Visual Speech Recognition

Mar 12, 2026

This work addresses the unclear dynamics of how audio-visual speech recognition (AVSR) systems weigh contributions from audio and visual modalities under noisy conditions. The authors propose Dr. SHAP-AV, a novel framework that introduces Shapley values into AVSR for the first time, quantifying modality contributions across three dimensions: global importance, generation process, and temporal alignment. Their analysis reveals that AVSR models remain significantly reliant on audio even at low signal-to-noise ratios (SNR), that modality weights are primarily governed by SNR and evolve dynamically during decoding, and that temporal alignment mechanisms exhibit robustness in noisy environments. Extensive experiments across two benchmarks and six state-of-the-art models validate the effectiveness of Dr. SHAP-AV, offering a new tool for interpretability and diagnostic analysis in AVSR research.

0 citationsRead paper

Evaluating Performance Drift from Model Switching in Multi-Turn LLM Systems

Mar 03, 2026

This study addresses the performance degradation caused by context mismatch when switching large language models (LLMs) in multi-turn dialogues—a phenomenon termed "silent drift." The work presents the first systematic characterization of this issue and introduces a benchmark evaluation framework based on a switching matrix. By employing pairwise turn-level bootstrap confidence intervals, the authors quantify the impact of model switching on dialogue performance across datasets such as CoQA and Multi-IF. A key innovation lies in decomposing the drift into prefix influence and suffix sensitivity, revealing systematic robustness or vulnerability of models to non-self-generated context. Experiments demonstrate that a single switch can alter Multi-IF’s strict success rate by −8 to +13 percentage points and induce CoQA F1 fluctuations of up to ±4 points, offering both theoretical insights and practical tools for effective risk monitoring.

0 citationsRead paper