Additionally, in the QFD literature, the Kano model is applied by assigning weights to different customer
attributes. Islam and Liu (1995) indicated that customer needs can be divided into three subgroups, i.e., basic,
one-dimensional and excitement. For each requirement, the raw importance is adjusted by multiplying a
weight that is calculated by an analytic hierarchy process. Similarly, using the dual importance grid, Robertshaw
(1995) classified the type of Kano element and suggested that customer needs should be re-prioritized:
the first priority is to deliver what is expected; the second is what is specified; the last is to provide the attractive
elements. Gerson (2003) showed a modified Kano method to determine the degree to which an attribute is
considered attractive or must-be by customers and how to integrate into the planning matrix of the QFD. Tan,
Tang, and Forrester (2004) analyzed customer satisfaction based on the Kano model and pointed out the
importance of product innovation in exceeding customer satisfaction