Investigating Mixture of Experts in Dense Retrieval

Fuente: arXiv
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Autores principales: Sokli, Effrosyni, Kasela, Pranav, Peikos, Georgios, Pasi, Gabriella
Formato: Preprint
Publicado: 2024
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author Sokli, Effrosyni
Kasela, Pranav
Peikos, Georgios
Pasi, Gabriella
author_facet Sokli, Effrosyni
Kasela, Pranav
Peikos, Georgios
Pasi, Gabriella
contents While Dense Retrieval Models (DRMs) have advanced Information Retrieval (IR), one limitation of these neural models is their narrow generalizability and robustness. To cope with this issue, one can leverage the Mixture-of-Experts (MoE) architecture. While previous IR studies have incorporated MoE architectures within the Transformer layers of DRMs, our work investigates an architecture that integrates a single MoE block (SB-MoE) after the output of the final Transformer layer. Our empirical evaluation investigates how SB-MoE compares, in terms of retrieval effectiveness, to standard fine-tuning. In detail, we fine-tune three DRMs (TinyBERT, BERT, and Contriever) across four benchmark collections with and without adding the MoE block. Moreover, since MoE showcases performance variations with respect to its parameters (i.e., the number of experts), we conduct additional experiments to investigate this aspect further. The findings show the effectiveness of SB-MoE especially for DRMs with a low number of parameters (i.e., TinyBERT), as it consistently outperforms the fine-tuned underlying model on all four benchmarks. For DRMs with a higher number of parameters (i.e., BERT and Contriever), SB-MoE requires larger numbers of training samples to yield better retrieval performance.
format Preprint
id arxiv_https___arxiv_org_abs_2412_11864
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Investigating Mixture of Experts in Dense Retrieval
Sokli, Effrosyni
Kasela, Pranav
Peikos, Georgios
Pasi, Gabriella
Information Retrieval
Artificial Intelligence
While Dense Retrieval Models (DRMs) have advanced Information Retrieval (IR), one limitation of these neural models is their narrow generalizability and robustness. To cope with this issue, one can leverage the Mixture-of-Experts (MoE) architecture. While previous IR studies have incorporated MoE architectures within the Transformer layers of DRMs, our work investigates an architecture that integrates a single MoE block (SB-MoE) after the output of the final Transformer layer. Our empirical evaluation investigates how SB-MoE compares, in terms of retrieval effectiveness, to standard fine-tuning. In detail, we fine-tune three DRMs (TinyBERT, BERT, and Contriever) across four benchmark collections with and without adding the MoE block. Moreover, since MoE showcases performance variations with respect to its parameters (i.e., the number of experts), we conduct additional experiments to investigate this aspect further. The findings show the effectiveness of SB-MoE especially for DRMs with a low number of parameters (i.e., TinyBERT), as it consistently outperforms the fine-tuned underlying model on all four benchmarks. For DRMs with a higher number of parameters (i.e., BERT and Contriever), SB-MoE requires larger numbers of training samples to yield better retrieval performance.
title Investigating Mixture of Experts in Dense Retrieval
topic Information Retrieval
Artificial Intelligence
url https://arxiv.org/abs/2412.11864