基于双仿射模型与指针网络联合建模的知识图谱问答模型

A Knowledge Graph Question Answering Model Based on Joint Biaffine Model and Pointer Network Modeling

  • 摘要: 现阶段基于知识图谱的问答研究主要集中在英文领域,中文领域因起步较晚,且缺乏足够的问答语料数据,发展相对滞后。中文中大量实体存在别名,增加了问答的复杂性。为此,文章提出了一种基于双仿射模型与指针网络联合建模的知识图谱问答模型(Prompt-Biaf-JointPN, PBJ)。首先,在Prompt模块采用思维链方法将多跳问题拆分为多个单跳问题;然后,针对每个单跳问题,Biaf模块以双仿射模型为输出层进行实体提及识别,并在JointPN模块将实体消歧与关系匹配任务统一建模为选择形式的阅读理解任务,从而获得中间答案;接着,在Prompt模块通过循环迭代机制,将上一跳的答案作为下一跳问题的实体提及,直到最终生成完整答案。为验证模型性能,在3个数据集(NLPCC-ICCPOL、KgCLUE、NLPCC-MH)上,将PBJ模型与Pipeline1、Pipeline2、TransferNet等11个基线模型进行了对比实验。对比实验结果验证了PBJ模型在中文语境下处理复杂问答任务的准确率:在单跳任务上,将PBJ模型去掉Prompt模块后的BJ模型的Hits@1值比最优的基线模型Pipeline2 w/Biaf高2.15%;在多跳任务上,PBJ模型的Hits@1值比最优的基线模型ChineseBERT高1.26%。最后,为验证文章提出的Prompt、Biaf、JointPN模块的有效性,进行了消融实验。消融实验结果表明这3个模块对提升PBJ模型性能均有重要贡献:分别缺少Prompt、Biaf、JointPN模块的3个模型的Hits@1值,相较于PBJ模型分别下降了2.13%、2.84%、6.51%。综上可知,PBJ模型通过联合建模实体消歧与关系匹配,可有效缓解中文知识图谱问答中实体别名复杂、语料稀缺等瓶颈,为中文多跳问答提供了一种实用且可扩展的新思路。

     

    Abstract: At present, research on knowledge graph-based question answering is primarily focused on the English domain. In contrast, the development in the Chinese domain lags behind due to its late start and the lack of sufficient question and answering (Q&A) corpus. The existence of numerous aliases for entities in Chinese further increases the complexity of question answering. To address these challenges, a knowledge graph-based question answering model PBJ (Prompt-Biaf-JointPN) has been proposed, in which biaffine model and pointer networks are jointly integrated. First, the Prompt module adopts a chain-of-thought approach to decompose multi-hop questions into multiple single-hop questions. Then, for each single-hop question, the Biaf module employs a biaffine model as the output layer to perform entity mention recognition, while the JointPN module unifies entity disambiguation and relation matching as a multiple-choice reading-comprehension task to obtain intermediate answers. Next, through a recursive iterative mechanism orchestrated by the Prompt module, the answer from the previous hop is fed as the entity mention for the next-hop question until the final complete answer is generated. To evaluate the model's performance, experiments were conducted on three datasets (NLPCC-ICCPOL, KgCLUE, and NLPCC-MH) against eleven existing models. The results demonstrate the PBJ model's accuracy: its BJ variant (Prompt module removed) exceeds the top single-hop baseline Pipeline2 w/Biaf by 2.15% in Hits@1, while the full PBJ surpasses the leading multi-hop baseline ChineseBERT by 1.26%, confirming its capability for complex question answering in the Chinese context. Finally, ablation studies were conducted to assess the individual contributions of the proposed Prompt, Biaf, and JointPN components. The results reveal that each module is instrumental to PBJ's perfor-mance: removing Prompt, Biaf, or JointPN respectively degrades Hits@1 by 2.13%, 2.84%, and 6.51% relative to the full model. Consequently, by jointly modeling entity disambiguation and relation matching, the PBJ model effectively mitigates the bottlenecks of abundant entity aliases and scarce corpora in Chinese KGQA, offering a practical and scalable new avenue for Chinese multi-hop question answering.

     

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