Collecting fuzzy perceptions from non-expert users

Since the concept of fuzzy set was defined in 1965 by Zadeh, numerous papers on fuzzy topics have been published and many of his seminal ideas have evolved in different directions. However, there is lack of natural and intuitive procedures to capture fuzzy perceptions from non-expert users. In this paper, we propose an innovative approach to solve this problem with a straightforward and repeatable mechanism based on a web gadget. The key benefit of this approach is that users obtain an immediate feedback thanks to the use of a visual spray pen metaphor. We also propose several algorithms to model these fuzzy perceptions with trapezoidal fuzzy set approximations. These algorithms are then evaluated though a real case study in order to test the usability and usefulness of the proposed gadget. One of the main conclusions extracted from this work suggests that the evaluation of the fitness of these approximations is intrinsically subjective, requiring further development and research.