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Evidential Neural Networks for Uncertainty-Based Document Re-ranking in QA Systems

초록/요약

The effectiveness of the two-step Retrieval-Augmented Generation (RAG) process in question-answering (QA) depends significantly on the accuracy of the re-ranking step, which identifies the most relevant context for generating answers. Traditional text reranking methods often rely on classification models that interpret predicted probabilities as relevance scores. However, standard deep learning classification models, which are trained to minimize prediction loss for point estimates, often suffer from poor calibration. To address this, we introduce the Evidential Document Re-Ranking (EDRR) model, which leverages Evidential Deep Learning (EDL) to improve the calibration of predicted probabilities and to quantify uncertainty in model predictions. The EDRR framework employ these calibrated probabilities and uncertainty measures to establish more dependable relevance scores for the re-ranking phase. Additionally, the uncertainty estimates can serve as a criterion for active learning, enabling the selection of diverse and informative training samples. Evaluations conducted on the Wikipedia-NQ dataset demonstrate that EDRR surpasses the performance of standard cross-encoder models, achieving up to a 10% improvement in mean average precision (mAP@10) within the top 10 results.

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목차

Introduction 1
Method 4
Evidential Re-rank Model Framework 4
Evidential-Bert Model 5
Evidential Relevance Score 7
Active Learning with Uncertainty Sampling 8
Experiments 9
Datasets 9
Hyperparameter Optimization 10
Comparison with Cross-Encoder 10
Performance of Uncertainty Sampling in Active Learning 12
Ranking with Uncertainty Filters 14
Related Work 16
Discussion 18
Conclusion 20

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