融合学习者知识吸收能力的深度知识追踪模型

Deep Knowledge Tracking Model Integrating Learners' Knowledge Absorptive Capacity

  • 摘要: 知识追踪旨在根据学习者历史答题记录预测其未来的答题情况,并对知识掌握程度加以评估。现有的大多深度知识追踪方法未能有效利用数据集中多样的行为信息,且在区分不同学习者的作答收益方面存在困难。针对这些问题,文章提出了一个融合学习者知识吸收能力的深度知识追踪模型(Knowledge Absorptive Capacity Deep Knowledge Tracing,KADKT):首先,为了解决行为信息利用不充分的问题,将提取到的行为信息分为显性行为和隐性行为,利用显性行为计算题目的难度信息和学习者的作答水平(平均作答时间和平均尝试次数),隐性行为表示学习者历史学习某一知识的情况;然后,为了个性化计算学习者的作答收益,提出了一种融合难度和平均作答情况的知识吸收能力建模方法;其次,从知识点层面和交互层面分别计算学习者的作答收益,以捕捉知识点对作答收益的独立贡献;最后,设计了一个遗忘模块来模拟学习者的知识遗忘,全面地更新学习者知识状态的变化。在3个公开数据集(ASSISTments2009、ASSISTments2017和Junyi Academy)上,将KADKT模型与6个基准模型(DKT、DKVMN、SAKT、AKT、LPKT、LBKT)开展对比实验。对比实验结果表明:KADKT模型在3个数据集上的曲线下面积(AUC)、准确率(ACC)和均方根误差(RMSE)均优于所有基准模型,其中,与所有基准模型相比,KADKT模型在ASSISTments2009数据集上的AUC、ACC值分别提高了2.6%~10.61%、3.28%~7.93%,RMSE值下降了2.24%~6.52%。此外,消融实验验证了KADKT模型中各模块的有效性,可视化分析证明KADKT模型可以有效地追踪学习者知识状态的变化。

     

    Abstract: The purpose of knowledge tracking is to predict learners' future answers and evaluate their knowledge mastery based on their historical answer records. Most existing deep knowledge tracking methods fail to effectively utilize the diverse behavioral information in datasets, and have difficulties in distinguishing the response benefits of different learners. To address these problems, a deep knowledge tracing model that integrates learners' knowledge absorption capacity (Knowledge Absorptive Capacity Deep Knowledge Tracing, KADKT) is proposed. Firstly, in order to solve the problem of insufficient utilization of behavioral information, the extracted behavioral information is divided into explicit behavior and implicit behavior, and the difficulty information and learners' answer level (ave-rage answer time and average number of attempts) of the question are calculated by explicit behavior. The implicit behavior represents the situation that the learner has learned a certain knowledge in history; secondly, in order to calculate the learner's answer return individually, a knowledge absorptive capacity modeling method that integrates the difficulty and the average answer situation is proposed; thirdly, the learner's answer return is calculated from the knowledge point level and the interaction level respectively to capture the independent contribution of the know-ledge point to the answer return; finally, a forgetting module is designed to simulate the learner's knowledge forgetting and comprehensively update the change of the learner's knowledge state. Comparative experiments are conducted between the KADKT model and six benchmark models DKT, DKVMN, SAKT, AKT, LPKT, and LBKT on three public datasets(ASSISTments2009, ASSISTments2017, and Junyi Academy). The results of the comparative experiments showed that the KADKT model outperformed other benchmark models in terms of area under the curve (AUC), accuracy (ACC), and root mean square error (RMSE) across the three datasets. Specifically, on the ASSISTments2009 dataset, compared with the benchmark models, the KADKT model achieved an increase of 2.6% to 10.61% in AUC, 3.28% to 7.93% in ACC, and a decrease of 2.24% to 6.52% in RMSE. In addition, the ablation experiment verified the validity of each module of the KADKT model, and the visual analysis proved that the KADKT model could effectively track the changes of learners' knowledge status.

     

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