arXiv:2411.16122cs.IR2024-11

解决大模型集成中性能下降问题,提升点击率预测稳定性。

From Collapse to Stability: A Knowledge-Driven Ensemble Framework for Scaling Up Click-Through Rate Prediction Models

  • 用知识迁移缓解子模型维度坍塌,增强知识多样性。
  • 集成更多子模型后点击率提升1.8%,且方差显著降低。
  • 无需调参的通用框架,适合大规模推荐系统部署。

点击率(CTR)预测在现代推荐系统中至关重要。尽管现有方法多采用集成网络提升性能,但通常仅限于两到三个子网络。增加子网络数量是否能持续提升性能以符合缩放定律尚不明确。本文研究了更大规模的集成网络,发现常用集成方法存在三大缺陷:(1)子网络数量增加时性能下降;(2)子网络表现出现剧烈波动且方差高;(3)子网络与集成结果间差异显著。我们从维度坍塌角度分析其根源:随着子网络增多,子网络内部坍塌加剧,导致知识丰度降低。为此,我们引入知识蒸馏(KD)和深度互学习(DML)来应对上述问题。实验表明,KD使模型更符合缩放定律,而DML降低子网络间方差并缩小与集成预测的差距。进一步结合两者,提出一种无需调参、模型无关的知识驱动集成框架(KDEF),适用于CTR预测。

原文摘要 · Abstract (English)

Click-through rate (CTR) prediction plays a crucial role in modern recommender systems. While many existing methods utilize ensemble networks to improve CTR model performance, they typically restrict the ensemble to only two or three sub-networks. Whether increasing the number of sub-networks consistently enhances CTR model performance to align with scaling laws remains unclear. In this paper, we investigate larger ensemble networks and find three inherent limitations in commonly used ensemble methods: (1) performance degradation as the number of sub-networks increases; (2) sharp declines and high variance in sub-network performance; and (3) significant discrepancies between sub-network and ensemble predictions. Meanwhile, we analyze the underlying causes of these limitations from the perspective of dimensional collapse: the collapse within sub-networks becomes increasingly severe as the number of sub-networks grows, leading to a lower knowledge abundance. In this paper, we employ knowledge transfer methods, such as Knowledge Distillation (KD) and Deep Mutual Learning (DML), to address the aforementioned limitations. We find that KD enables CTR models to better follow scaling laws, while DML reduces variance among sub-networks and minimizes discrepancies with ensemble predictions. Furthermore, by combining KD and DML, we propose a model-agnostic and hyperparameter-free Knowledge-Driven Ensemble Framework (KDEF) for CTR Prediction.

CTR预测集成学习知识蒸馏推荐系统

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