Design of experiment on electrical engineering design representations

Abstract

Over the decades humans' need and desire for artifacts has increased in quantity, variety, and complexity. Consequently, quality and first to market have become the goals of many engineering firms. This in turn has put pressure on engineering education programs to produce professionals proficient and able to design quality products fast. Researchers have studied design from many different perspectives. One of the perspectives is the role of representations in design. Internal representations belong in our mental world while external representations are in our physical world. This thesis provides experimental evidence on the role of electrical engineering external representations on three design outcomes. The basis of this thesis is a framework developed by Goel (1995). Goel's framework of notationality classifies external representations into three categories: notational, discursive, and non-notational systems. Non-notational systems are essential for creativity because they encourage lateral transformations and discourage vertical transformations during design. Consequently, this improves design outcome because it encourages divergence and prevents premature convergence. Lateral and vertical transformations are cognitive movements between and within ideas respectively. This thesis attempts to test Goel's theory by performing a 23 factorial design experiment in the electrical engineering domain. The three factors are the three categories of external representations and the response variables are solution quality, productivity of design, and the number of ideas generated. This thesis also briefly explores transformations relation to outcome variables and representations. Analysis of variance technique with the data reveals that the use of non-notational and discursive systems increases solution quality and productivity of design. Use of notational systems increases the number of ideas generated, which contradicts Goel's (1995) theory. Lateral transformations are better correlated to quality than are vertical transformations. The experimental results indicate that use of a variety of external representations leads to better design outcomes, specifically representations of non-notational and discursive systems. Electrical engineering instructors may want to formally teach students to design by using non-notational and discursive systems and also re-consider their textbook selection criteria.