i-Align: an interpretable knowledge graph alignment model

Knowledge graphs (KGs) are becoming essential resources for many downstream applications. However, their incompleteness may limit their potential. Thus, continuous curation is needed to mitigate this problem. One of the strategies to address this problem is KG alignment, i.e., forming a more complete KG by merging two or more KGs. This paper proposes i-Align, an interpretable KG alignment model. Unlike the existing KG alignment models, i-Align provides an explanation for each alignment prediction while maintaining high alignment performance. Experts can use the explanation to check the correctness of the alignment prediction. Thus, the high quality of a KG can be maintained during the curation process (e.g., the merging process of two KGs). To this end, a novel Transformer-based Graph Encoder (Trans-GE) is proposed as a key component of i-Align for aggregating information from entities' neighbors (structures). Trans-GE uses Edge-gated Attention that combines the adjacency matrix and the self-attention matrix to learn a gating mechanism to control the information aggregation from the neighboring entities. It also uses historical embeddings, allowing Trans-GE to be trained over mini-batches, or smaller sub-graphs, to address the scalability issue when encoding a large KG. Another component of i-Align is a Transformer encoder for aggregating entities' attributes. This way, i-Align can generate explanations in the form of a set of the most influential attributes/neighbors based on attention weights. Extensive experiments are conducted to show the power of i-Align. The experiments include several aspects, such as the model's effectiveness for aligning KGs, the quality of the generated explanations, and its practicality for aligning large KGs. The results show the effectiveness of i-Align in these aspects.

TRAILER: Transformer-based Time-wise Long Term Relation Modeling for Citywide Traffic Flow Prediction

Traffic flow prediction is a crucial task in enabling efficient intelligent transportation systems and smart cities. Although there has been rapid progress in this area in the last few years, given the major advances of deep learning techniques, it remains a challenging task because of the inherent periodic characteristics of traffic flow sequence. To incorporate the periodicity in the prediction process, existing methods have observed three components separately as the input of prediction models, i.e., the closeness, period, and trend components. The long term relation of these components has not been fully addressed. In this paper, we present a novel architecture, TRAILER (TRAnsformer-based tIme-wise Long tErm Relation modeling), to predict traffic flows more effectively. First, we explicitly design a Transformer based long term relation prediction module to model the long term relation and predict the periodic relation to be used for the downstream task. Second, we propose a consistency module at the target time interval, in order to model the consistency of the predicted periodic relation and the relation inferred from the predicted traffic flow tensor. Finally, based on the consistency module, we introduce a consistency loss to stabilize the training process and further improve the prediction performance. Through extensive experiments, we show the superiority of the proposed method on three real-world datasets and the effectiveness of each module in TRAILER.