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    Uni-LSDPM:基于预训练的统一在线学习会话退出预测模型

    Uni-LSDPM: A Unified Online Learning Session Dropout Prediction Model Based on Pre-Training

    • 摘要: 为了辅助学习者维持在线学习的连贯性以引导最优学习路径的执行,智能辅导系统(intelligent tutoring system,ITS)需要及时发现学习者退出学习的倾向,在合适的时间采取相应的干预措施,因此,在线学习会话退出预测研究十分必要. 然而,与传统的课程辍学相比,会话退出发生的频率更高,单次学习时长更短,故需要在有限的行为数据中对学习会话退出状态进行准确预测. 因此,学习行为的碎片性和预测结果的即时性、准确性是学习会话退出预测任务的挑战和难点. 针对会话退出预测任务,提出了一种基于预训练-微调的统一在线学习会话退出预测模型 (unified online learning session dropout prediction model,Uni-LSDPM). 该模型采用多层Transformer结构,分为预训练阶段和微调阶段. 在预训练阶段,使用双向注意机制对学习者连续行为交互特征序列的特征表示进行学习. 在微调阶段,应用序列到序列(sequence-to-sequence,Seq2Seq)的注意力机制对学习者连续行为交互特征序列与退出状态联合序列进行学习. 基于EdNet公共数据集对模型进行预训练和微调,通过消融实验以获得最佳预测效果,并基于多个数据集进行了对比测试实验. 实验结果表明,Uni-LSDPM在AUC和ACC方面优于现有的模型,并证明该模型具有一定的鲁棒性和扩展性.

       

      Abstract: To assist learners in maintaining the continuity of online learning and guiding the implementation of the optimal learning path, the intelligent tutoring system (ITS) needs to detect the tendency of learners to withdraw from learning in time and take corresponding intervention measures at the right time. Therefore, online learning session dropout prediction research is necessary. However, compared with traditional course dropouts, session dropouts occur more frequently and with shorter single study sessions. Session dropout requires the accurate prediction of learning session dropout state based on limited learning behavior feature data. Therefore, the fragmentation of learning behavior and the immediacy and accuracy of prediction results are the challenges and difficulties of learning session dropout prediction tasks. For the session dropout prediction task, we propose a unified online learning session dropout prediction model (Uni-LSDPM). Based on the pre-training and fine-tuning paradigm, Uni-LSDPM uses a multi-layer Transformer structure. In the pre-training stage, a bidirectional attention mechanism is used to learn the representation of sequence of learners’ continuous behavioral interaction features. In the fine-tuning stage, a sequence-to-sequence (Seq2Seq) attentional mechanism is used to learn the sequence combination of the learner’s continuous behavioral interaction features and dropout state. The proposed model is pre-trained and fine-tuned based on the EdNet public dataset, and the best prediction effect is obtained through ablation experiment. Comparative experiments are conducted based on multiple datasets. Experimental results show that Uni-LSDPM outperforms existing models in terms of AUC and ACC, and prove that the model has certain robustness and scalability.

       

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