Community question answering (CQA) websites have grown rapidly, but they face a gap between questions and answerers. This gap causes delays in getting answers and overwhelms potential answerers. Expert recommendation (ER) can bridge this gap by providing suitable answerers for the newly posted questions in time. However, most ER methods have some limitations. First, they focus on the representation of a user’s interest, but they ignore their ability to give high-quality answers (user expertise). Second, they do not consider that the answerers’ interests and expertise may change over time. Third, they only use the accepted answer as a good example, but they ignore other good answers that are not accepted. To address these issues, we propose MATER, a Bi-level Matching-Aggregation Model for Time-Aware Expert Recommendation to address these issues. MATER utilizes a matching-aggregation framework at two levels of sentence and question. MATER first matches the target question with each question in the user’s profile by a sentence-level matching-aggregation model. Next, the question matching results are aggregated by a proposed multi-perspective time-aware aggregation layer that considers both time-aware interest and expertise of a user. We propose to employ a listwise loss function to train our model, which takes into consideration all potential experts in the ranking strategy. Experimental results on six real-world CQA datasets from different domains demonstrate that MATER significantly outperforms state-of-the-art ER methods.
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