论文标题

模型感的对比学习:逃避困境

Model-Aware Contrastive Learning: Towards Escaping the Dilemmas

论文作者

Huang, Zizheng, Chen, Haoxing, Wen, Ziqi, Zhang, Chao, Li, Huaxiong, Wang, Bo, Chen, Chunlin

论文摘要

对比度学习(CL)连续地取得了多个领域的显着突破。但是,最常见的基于Infonce的方法遭受了一些困境,例如\ textIt {均匀性 - 耐受性困境}(UTD)和\ textit {渐变{渐变减少},这两种}与$ \ nathcal {p} _ {ij} $ term term ter。已经确定UTD会导致意外的性能下降。我们认为温度的固定性应归咎于UTD。为了应对这一挑战,我们通过提出一种模型吸引的对比度学习(MACL)策略来丰富CL损失家族,该策略的温度适应了反映实例歧视任务的基本信心的对齐程度,然后使CL损失能够调整惩罚性的惩罚强度,以适应艰苦的负面影响。关于另一个难题,降低了梯度问题,我们得出了涉及梯度缩放因子的限制,这使我们可以从统一的角度解释为什么最近的某些方法有效地使用较少的负面样本有效,并立即呈现梯度重新加权以避免这种困境。在视觉,句子和图形模态中广泛的杰出经验结果验证了我们方法在表示和下游任务方面的一般改进。

Contrastive learning (CL) continuously achieves significant breakthroughs across multiple domains. However, the most common InfoNCE-based methods suffer from some dilemmas, such as \textit{uniformity-tolerance dilemma} (UTD) and \textit{gradient reduction}, both of which are related to a $\mathcal{P}_{ij}$ term. It has been identified that UTD can lead to unexpected performance degradation. We argue that the fixity of temperature is to blame for UTD. To tackle this challenge, we enrich the CL loss family by presenting a Model-Aware Contrastive Learning (MACL) strategy, whose temperature is adaptive to the magnitude of alignment that reflects the basic confidence of the instance discrimination task, then enables CL loss to adjust the penalty strength for hard negatives adaptively. Regarding another dilemma, the gradient reduction issue, we derive the limits of an involved gradient scaling factor, which allows us to explain from a unified perspective why some recent approaches are effective with fewer negative samples, and summarily present a gradient reweighting to escape this dilemma. Extensive remarkable empirical results in vision, sentence, and graph modality validate our approach's general improvement for representation learning and downstream tasks.

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