论文标题
通过基于密度间隙的正则化改善变异自动编码器
Improving Variational Autoencoders with Density Gap-based Regularization
论文作者
论文摘要
变异自动编码器(VAE)是NLP中强大的无监督学习框架之一,用于潜在表示学习和潜在的导向生成。 VAE的经典优化目标是最大化证据下限(ELBO),该界限包括产生的有条件可能性和负kullback-leibler(KL)差异的正规化差异。实际上,优化ELBO通常会导致所有样品的后验分布收敛到相同的退化局部最佳最佳,即后置崩溃或KL消失。提出了有效的方法来防止VAE的后置崩溃,但我们观察到它们本质上是在后塌陷和孔问题之间进行权衡的,即,汇总的后验分布与先前的分布之间的不匹配。为此,我们介绍了新的训练目标,通过基于概率的密度密度差距,通过新颖的正则化解决两个问题,从而解决两个问题。通过对语言建模,潜在空间可视化和插值的实验,我们表明我们提出的方法可以有效地解决这两个问题,从而超过了潜在导向生成中现有的方法。据我们所知,我们是第一个共同解决孔问题和后部崩溃的人。
Variational autoencoders (VAEs) are one of the powerful unsupervised learning frameworks in NLP for latent representation learning and latent-directed generation. The classic optimization goal of VAEs is to maximize the Evidence Lower Bound (ELBo), which consists of a conditional likelihood for generation and a negative Kullback-Leibler (KL) divergence for regularization. In practice, optimizing ELBo often leads the posterior distribution of all samples converge to the same degenerated local optimum, namely posterior collapse or KL vanishing. There are effective ways proposed to prevent posterior collapse in VAEs, but we observe that they in essence make trade-offs between posterior collapse and hole problem, i.e., mismatch between the aggregated posterior distribution and the prior distribution. To this end, we introduce new training objectives to tackle both two problems through a novel regularization based on the probabilistic density gap between the aggregated posterior distribution and the prior distribution. Through experiments on language modeling, latent space visualization and interpolation, we show that our proposed method can solve both problems effectively and thus outperforms the existing methods in latent-directed generation. To the best of our knowledge, we are the first to jointly solve the hole problem and the posterior collapse.