In a task-oriented dialog system, the goal of dialog state tracking (DST) is to monitor the state of the conversation from the dialog history. Recently, many deep learning based methods have been proposed for the task. Despite their impressive performance, current neural architectures for DST are typically heavily-engineered and conceptually complex, making it difficult to implement, debug, and maintain them in a production setting. In this work, we propose a simple but effective DST model based on BERT. In addition to its simplicity, our approach also has a number of other advantages: (a) the number of parameters does not grow with the ontology size (b) the model can operate in situations where the domain ontology may change dynamically. Experimental results demonstrate that our BERT-based model outperforms previous methods by a large margin, achieving new state-of-the-art results on the standard WoZ 2.0 dataset. Finally, to make the model small and fast enough for resource-restricted systems, we apply the knowledge distillation method to compress our model. The final compressed model achieves comparable results with the original model while being 8x smaller and 7x faster.

本文提出一种基于BERT的简单而有效的对话状态跟踪模型，避免了当前神经架构通常存在的繁琐和复杂，具有不随本体论规模增长和适用于领域本体动态变化的优点。经实验验证，该模型在标准WoZ 2.0数据集上显著优于以往方法，经知识蒸馏压缩后性能依旧可与原模型相媲美，在资源受限的系统中表现出出色的效果。

面向资源受限系统的简单而有效的BERT模型用于对话状态跟踪