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Abstract

A Pen-Based Statics Tutoring SystemWe present an intelligent pen-based tutoring system for Engineering Statics. The systemscaffolds students in the construction of free-body diagrams and equilibrium equations for planardevices comprised of multiple bodies (frames and machines). Tutoring systems have been widelystudied and applied to a variety of subjects, but most systems are based on GUI interfaces.Research shows that transfer from training to testing is greater when training and testingenvironments are similar, suggesting benefits from tutoring systems with interfaces that matchreal-world problem-solving environments. Thus, our aim is the creation of a pen-based tutoringsystem that scaffolds students in the same way they ordinarily solve problems with paper andpencil. To use our system, a student uses a stylus to sketch free body diagrams and equilibriumequations on a tablet computer. Recognition algorithms interpret the handwritten input, and atutoring engine provides tutorial feedback. With our system, students construct solutions fromscratch, rather then selecting from among predefined choices, as is often the case with GUI-based systems.Free body diagrams are a fundamental tool for solving Statics problems, yet many studentsstruggle with how to create and use them. Our system scaffolds students through use of a“system boundary” metaphor. To construct a free body diagram, the student first sketches aboundary around the system of interest. This boundary helps make explicit the distinctionbetween external forces, which are included on the free body diagram, and internal forces, whichare not. To complete a free body diagram, the student augments the boundary with the forces thatact on it.Our tutoring engine, which is based on a “buggy-rules” approach, provides tutorial feedback onsystem boundaries, free body diagrams, and equilibrium equations. To promote problem-solvingskills, feedback is provided hierarchically: general suggestions are given first, and specificguidance is provided only when that is inadequate. The buggy-rules are based on a detailedanalysis of a corpus of student work.We will present results of an initial study aimed at evaluating the usability and educationalefficacy of the system. In this study, which focused only on free body diagrams and notequilibrium equations, learning gains were measured with pre- and posttests. After only a briefexposure to the system, we found significant improvements in students’ ability to constructcorrect free body diagrams and a marked reduction in solution time. An attitudinal surveyrevealed that students found the system to be an effective learning tool and that they preferredthe pen-based user interface to traditional GUI interfaces.