Case-Based Advice System for Novice Programs Written in Assembly Language

我们提出了一种在程序设计教育中使用基于案例的推理方法来为新手程序提供建议的方法。我们提供建议的目标项目被称为千载难逢项目。险些错过的程序是指不能正常运行的程序，但非常接近正确的程序。我们提出了一个循序渐进的建议模型。也就是说，建议系统首先给出小提示，然后根据需要提供更多提示或详细建议。与获得详细建议的案例相比，学生在解决小提示问题时会获得更多的信心。第一种方法是基于与建议案例的相似度来生成建议句子，其中包括一个险些未命中的程序作为问题描述和关于该程序的建议句子作为解决方案描述。第二种方法是基于目标险些命中方案和正确方案之间的差异来生成建议。基于这些思想，我们实现了一个基于简单汇编语言CASL II的基于案例的咨询系统，该系统已经在实际的课堂上得到了应用，结果表明案例咨询系统是可行的。特别是，我们发现基于差异的方法非常有用。由于基于差异的方法在教师评价学生提交的程序时使用自动添加到案例库的评估案例，因此即使案例库一开始是空的，也使用基于差异的方法来呈现建议句子。

We worked out a method of giving advice for novice programs using a case-based reasoning approach in programming education. Our target programs for the advice are called near-miss programs. A near-miss program is a program that does not run properly but is rather close to correct programs.We proposed a model of giving step-by-step advice. That is, the advice system gives small hints at first and then gives more hints or detailed advice later as needed. Students will gain more confidence when they solve problems with small hints than in cases where they got detailed advice.We also proposed two case-based methods of generating advice sentences. The first method is to generate advice sentences based on the similarity to advice cases, which include a near-miss program as a problem description and advice sentences on the program as a solution description. The second method is advice generation based on the difference between the target near-miss program and a correct program. There are many correct programs in evaluation case-bases of the evaluation assistant system we already implemented.Based on these ideas, we implemented a case-based advice system for a simple assembly language CASL II. The system had been utilized in actual classes and the results suggested that the case-based advice system was useful. In particular, we found that the difference-based method was very useful. Advice sentences were presented by the difference-based method even if case-bases were empty at first, because the difference-based method uses evaluation cases which are added to the case-base automatically when teachers evaluate students' submitted programs.