Abstract:

University students demand many exercises for practicing during their undergraduate courses. Although there are many resources where they can find proposed exercises, specially for basic courses, these resources include a fixed and limited set of proposed exercises. The students usually want to repeat similar exercises till they are sure they have the skill to solve it. Additionally they demand fast feedback about their trials. With the development of the European Higher Education Area, the work of the students must be assessed and this could be seen as a higher workload for the instructors, so the development of tools that help in the assignment and assessment of students work is necessary. Here, a tool that automatically generates thousands of numerical and wording variations of the same exercise and automatically assesses the solution given by the student is presented. The selected exercise is the convolution of two signals, a basic exercise for Signals and Systems undergraduate course for Electrical Engineering and Electronics students. Wording variations of the exercise include discrete time and continuous time signals, to find the output of a linear and invariant system for a given input and different presentations of the signals (analytic expressions, graphical or tabulated representation for the time span where the signals have non zero values). Both wording and numerical variations are obtained from a single seed. The remainders of division of the seed by different divisors are calculated and used to obtain a large set of variations of the exercise. One of these remainders is used to group the variations of the exercise by difficulty grade. The teacher can use this tool to automatically assign personalized exercises for each student that attends his/her course. This personalized assignment makes the cheating among students more difficult than when the same exercise is assigned to all the students. The teacher can be sure that all the assignments are in the same difficulty group. Moreover, this tool automatically grades the solution given by the student, so can be used as an assessment tool by the teacher. The basic algorithm to generate the variations in this exercise could be extended to almost all typical exercises in Signal and Systems course.

Keywords:

Computer based learning, computer based assessment, automatic item generation, electrical engineering and electronics.