In this paper, we propose to formulate the task-oriented dialogue system as the purely natural language generation task, so as to fully leverage the large-scale pre-trained models like GPT-2 and simplify complicated delexicalization prepossessing. However, directly applying this method heavily suffers from the dialogue entity inconsistency caused by the removal of delexicalized tokens, as well as the catastrophic forgetting problem of the pre-trained model during fine-tuning, leading to unsatisfactory performance. To alleviate these problems, we design a novel GPT-Adapter-CopyNet network, which incorporates the lightweight adapter and CopyNet modules into GPT-2 to achieve better performance on transfer learning and dialogue entity generation. Experimental results conducted on the DSTC8 Track 1 benchmark and MultiWOZ dataset demonstrate that our proposed approach significantly outperforms baseline models with a remarkable performance on automatic and human evaluations.

本文提出了一种基于大规模预训练模型（如GPT-2）的任务驱动对话系统纯自然语言生成任务，以简化复杂的词语替换处理，但是直接使用会遇到对话实体不一致性和预训练模型精调时的灾难性遗忘问题，因此我们设计了一种新的GPT-Adapter-CopyNet网络，它将轻量级adapter和CopyNet模块融入GPT-2，以实现更好的迁移学习和对话实体生成，而且实验结果表明，我们的方法在自动和人类评估方面的性能显著优于基线模型。

以任务为导向的对话系统作为自然语言生成