Online sales prediction via trend alignment-based multitask recurrent neural networks

While business trends are constantly evolving, the timely prediction of sales volume offers precious information for companies to achieve a healthy balance between supply and demand. In practice, sales prediction is formulated as a time series prediction problem which aims to predict the future sales volume for different products with the observation of various influential factors (e.g. brand, season, discount, etc.) and corresponding historical sales records. To perform accurate sales prediction under the offline setting, we gain insights from the encoder-decoder recurrent neural network (RNN) structure and have proposed a novel framework named TADA (Chen et al., in: ICDM, 2018) to carry out trend alignment with dual-attention, multitask RNNs for sales prediction. However, the sales data accumulates at a fast rate and is updated on a regular basis, rendering it difficult for the trained model to maintain the prediction accuracy with new data. In this light, we further extend the model into TADA(+), which is enhanced by an online learning module based on our innovative similarity-based reservoir. To construct the data reservoir for model retraining, different from most existing random sampling-based reservoir, our similarity-based reservoir selects data samples that are "hard" for the model to mine apparent dynamic patterns. The experimental results on two real-world datasets comprehensively show the superiority of TADA and TADA(+) in both online and offline sales prediction tasks against other state-of-the-art competitors.