Hard or False: Keep the Balance for Negative Sampling in Knowledge Graphs

Negative sampling is an essential part in knowledge graph embedding, which offers significant advantages to numerous downstream related tasks. There are two kinds of important negatives: hard and false negatives. Hard negatives are the negatives which are difficult to distinguish from positive samples, while false negatives are positive samples which are mistakenly identified as negatives. Harnessing hard negatives effectively can make the model more discriminative, and reducing false negatives can avoid misleading the model during training. Therefore, the two kinds of negatives are essential in high-quality negative sampling. However, the present negative sampling methods face two shortcomings: 1.judging one negative is hard or false mainly relies on score functions; 2. difficulty in balancing the impact of hard and false negatives. In this paper, we absorb bigram language model and propose a novel criterion to help verify the negatives are hard or false, and discuss how to keep the balance between hard and false negatives. Experiments on four representative score functions and two public datasets demonstrate the effects of the proposed negative sampling method.