Graph convolutional networks (GCNs) -- which are effective in modeling graph structures -- have been increasingly popular in knowledge graph completion (KGC). GCN-based KGC models first use GCNs to generate expressive entity representations and then use knowledge graph embedding (KGE) models to capture the interactions among entities and relations. However, many GCN-based KGC models fail to outperform state-of-the-art KGE models though introducing additional computational complexity. This phenomenon motivates us to explore the real effect of GCNs in KGC. Therefore, in this paper, we build upon representative GCN-based KGC models and introduce variants to find which factor of GCNs is critical in KGC. Surprisingly, we observe from experiments that the graph structure modeling in GCNs does not have a significant impact on the performance of KGC models, which is in contrast to the common belief. Instead, the transformations for entity representations are responsible for the performance improvements. Based on the observation, we propose a simple yet effective framework named LTE-KGE, which equips existing KGE models with linearly transformed entity embeddings. Experiments demonstrate that LTE-KGE models lead to similar performance improvements with GCN-based KGC methods, while being more computationally efficient. These results suggest that existing GCNs are unnecessary for KGC, and novel GCN-based KGC models should count on more ablation studies to validate their effectiveness. The code of all the experiments is available on GitHub at https://github.com/MIRALab-USTC/GCN4KGC.

本文通过建立变体研究了基于 Graph Convolutional Networks 的知识图谱完成模型，在实验中发现了与预期相反的图结构建模并不对模型性能产生显著影响，而实体表示的转换是改善性能的关键因素。作者基于此提出了LTE-KGE框架，通过线性转换实体嵌入向现有的KGE模型中添加GCNs模块以达到类似的性能提升。实验结果表明，与GCN-based KGC方法相比，LTE-KGE模型在性能上有类似的提升，同时更具计算效率。因此，本文表明GCNs对于KGC并不必要，新型基于GCNs的KGC模型需要进行更多的消融研究来验证其有效性。

知识图谱补全中的图卷积网络再思考