David C. Littman

Designing documentation to compensate for delocalized plans

Conceptual representation methods play a significant role in facilitating the software process. Recent studies explore and clarify the use of these representations and their impact on progress.

Mental models and software maintenance

Abstract Understanding how a program is constructed and how it functions are significant components of the task of maintaining or enhancing a computer program. We have analyzed vidoetaped protocols of experienced programmers as they enhanced a personnel data base program. Our analysis suggests that there are two strategies for program understanding, the systematic strategy and the as-needed strategy. The programmer using the systematic strategy traces data flow through the program in order to understand global program behavior. The programmer using the as-needed strategy focuses on local program behavior in order to localize study of the program. Our empirical data show that there is a strong relationship between using a systematic approach to acquire knowledge about the program and modifying the program successfully. Programmers who used the systematic approach to study the program constructed successful modifications; programmers who used the as-needed approach failed to construct successful modifications. Programmers who used the systematic strategy gathered knowledge about the causal interactions of the programs functional components . Programmers who used the as-needed strategy did not gather such causal knowledge and therefore failed to detect interactions among components of the program.

The Knowledge Required for Tutorial Planning: An Empirical Analysis

Abstract A significant portion of tutorial interactions revolve around the bugs a student makes. When a tutor performs an intervention to help a student fix a programming bug, the problem of deciding how to help the student appears to require extensive planning. In this article, we identify five considerations tutors appear to take into account when they plan tutorial interventions for students’ bugs. Using data collected from human tutors working in the domain of introductory computer programming, we (1) identify the knowledge tutors use when they reason about the five planning considerations, and (2) show that tutors are consistent in the ways that they use the kinds of knowledge to reason about students’ bugs.

Intelligent control of action: a brief case for cases

It is suggested that developing systems that exhibit intelligent, adaptive control of action can be usefully approached from the perspective of symbolic case-based problem solving supported by a distributed memory representation for the cases. It is also suggested that (1) attempting to prewire solutions to a wide range of potential planning failures is not feasible, either practically or theoretically, and (2) general planning approaches to failure recovery may not be an attractive solution. A possible strategy for manipulating stored cases to make them useful in contexts from which they did not originally result is briefly described.<<ETX>>