Spatiotemporal knowledge graph completion via diachronic and transregional word embedding

Knowledge Graph Completion (KGC) is an essential application in the field of knowledge graphs (KGs) that attempts to fill in the missing information in the process of KG modelling. With the popularity of temporal knowledge graphs (TKGs), a wide range of techniques based on temporal knowledge graph completion (TKGC) have appeared, solving the issue of real-world knowledge with temporal properties. However, there is little study on KGC with spatiotemporal attributes, some real-world data include both spatial and temporal attributes. Effectively handling the completion of missing entities or predicates in spatiotemporal knowledge graphs (STKGs) is an important challenge. Our study fills the gap in knowledge completion techniques in the field of STKG. We present a model for completion based on the well-known tensor factorization canonical polyadic (CP) decomposition. It introduces temporal and spatial attributes into the decomposition vector to achieve entity and link predictions. We name it diachronic and transregional word embedding (DT-WE), which includes two different modules: the embedding framework and the scoring module. Firstly, send the vectors to the embedding framework to get the new vector representation, then, we send it to the scoring module to compute, and finally, the resulting values are added together to compute the prediction probability. We conducted extensive experiments on three real-world STKGs: YAGO10K, Wikidata40K and Opensky. The results indicate that the newly introduced spatiotemporal attributes not only improve accuracy in predicting entities and predicates compared to temporal models but also achieve state-of-the-art performance with lower spatial complexity.