A Bayes Net Toolkit for Student Modeling in Intelligent Tutoring Systems

  • Kai-min Chang
  • Joseph Beck
  • Jack Mostow
  • Albert Corbett
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4053)

Abstract

This paper describes an effort to model a student’s changing knowledge state during skill acquisition. Dynamic Bayes Nets (DBNs) provide a powerful way to represent and reason about uncertainty in time series data, and are therefore well-suited to model student knowledge. Many general-purpose Bayes net packages have been implemented and distributed; however, constructing DBNs often involves complicated coding effort. To address this problem, we introduce a tool called BNT-SM. BNT-SM inputs a data set and a compact XML specification of a Bayes net model hypothesized by a researcher to describe causal relationships among student knowledge and observed behavior. BNT-SM generates and executes the code to train and test the model using the Bayes Net Toolbox [1]. Compared to the BNT code it outputs, BNT-SM reduces the number of lines of code required to use a DBN by a factor of 5. In addition to supporting more flexible models, we illustrate how to use BNT-SM to simulate Knowledge Tracing (KT) [2], an established technique for student modeling. The trained DBN does a better job of modeling and predicting student performance than the original KT code (Area Under Curve = 0.610 > 0.568), due to differences in how it estimates parameters.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2006

Authors and Affiliations

  • Kai-min Chang
    • 1
  • Joseph Beck
    • 1
  • Jack Mostow
    • 1
  • Albert Corbett
    • 1
  1. 1.Project LISTEN, School of Computer ScienceCarnegie Mellon UniversityPittsburghUSA

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