Application of Test Method Using Multimedia

Ro Yong Sim, a researcher at the Faculty of Electrical Engineering, has applied, in her subject Servo Motor Design, a new examination method in which students are given questions in multimedia and allowed to consult references, in contrast with traditional examination methods in which only theoretical problems and complicated design calculations were given, in order to evaluate correctly their theoretical and practical abilities to design different servo motors.

Primarily, in order to evaluate students’ design ability she gives questions for the characteristic parameters of servo motors whose dimensional structures difficult to be expressed in words are shown in movies and images and allows them to consult all available references to calculate them.

The questions are made to be solved only when they have gone through several steps of calculation while grasping the correct meaning of all the variables in complicated design equations.

Then the students, on the basis of the decision of what kind of servo motor it is from the images and movies, calculate the characteristic parameters such as time constant or inertia, which makes it possible to evaluate their design ability for a particular object.

Secondly, she presents questions in images to evaluate the practical ability to understand design plans.

In other words, she blanks or makes errors in some parts of the plan of a servo motor shown in image to make the students correct them.

The students are supposed to write on their exam paper which parts contain errors and how the errors should be corrected.

Thirdly, she uses questions to estimate the computer aided design ability of the students.

For example, to test the analysis ability of the students by Ansoft Maxwell software, she distributes to students’ computers a program file which has analysis conditions beforehand and encounters an error because of some mistakes made during modeling and analyzing. The students come to use some software tools to correct the errors. She makes them write or draw on the paper the cause of errors, the resultant parameter values and graphs.

Fourthly, she uses multimedia for questions to estimate their theoretical knowledge, too.

For example, while showing a movie in which a three-phase hybrid-type stepper motor is rotating, she pauses the movie at any moment and asks students to draw an equivalent magnetic circuit at that point. This enables her to evaluate if they have a correct understanding in detail of the operating principle of the stepper motor.

Finally, she uses multimedia to evaluate the creative ability of the students.

For example, in the past she used to ask, “What methods to decrease the cogging torque of a permanent magnet electric machine are there?”, but now she first shows the parts and assemblies of a permanent magnet synchronous motor in multimedia and then gives questions like how this motor could decrease cogging torque and what else could be done for that.

So she can evaluate on the basis of a particular object if the students grasp the theory and know how to apply it to the practice.

Besides, by giving a task to design permanent magnet about that object, she could test the creative design ability of the students in a comprehensive way such as if they select the optimal pole embrace to minimize the cogging torque, if they set reasonable air gap, if they choose proper material for permanent magnet or if they rationally design dimensions like the width and the thickness of the poles.

She makes such questions with PowerPoint software, sends them to every computer of the students, and allows them to use all the materials such as computers, textbooks and reference books during the test while she prevents them from exchanging information through the network.

Applying this testing method she has been able to correctly evaluate the practical ability as well as the theoretical knowledge of the students and fully stimulate the interest in their study.