# Smart Product Design Process through the Implementation of a Fuzzy Kano-AHP-DEMATEL-QFD Approach
## 3 Proposed methodology
### Kano Model  
The approach used by Kano to address the non-linear relationship between the fulfillment of customer needs (Figure 3) and overall customer satisfaction consists of three steps as follows: Kano questionnaire, Kano evaluation table, and Kano category result [24]. \(\bullet\) Kano questionnaire:  
The Kano questionnaire contains a set of question pairs for each product attribute. The question set includes a functional (product or service having a particular feature) and a dysfunctional (product or service not having a particular feature) form, capturing customers' responses in both scenarios of a particular feature. The questionnaire is deployed to several customers, and each answer pair is aligned with the Kano evaluation table, highlighting the individual customer's perception of a product attribute. There are five possible responses for each question, whether it is in the functional or dysfunctional form [24]. Kano evaluation table consists basically of a template where each pair of answers for the functional and dysfunctional question for certain customer need is allocated. The location of the customer  
Figure 3: Kano model. Figure 2: Proposed approach. response, in a particular cell of this template (Table 2), allows the surveyor to place that customer need in one of the five requirement categories Kano has established [24]. * I like it this way
* Must be this way
* Indifferent
* Live with it this way
* I dislike it this way  
* Kano category result:  
This step consists of the allocation of each of the customer needs (product/service feature) in one of the categories of the Kano evaluation table, after obtaining the Kano questionnaire from the different customers. The allocation usually is made considering the most frequent pair of answers. Indifference and reverse factors are quality attributes that have not much relevance to fulfill the improvement of overall satisfaction. Nevertheless, the Kano diagram provides a rough understanding of the customer's satisfaction, and it only allows a qualitative assessment of product attributes [24]. To translate this qualitative understanding into a more convenient and objective way, quantitative measures are incorporated by assigning some scales in terms of customer satisfaction/dissatisfaction level [24]. However, the resulting Kano category is still qualitative and cannot precisely reflect the extent to which customers are satisfied [24]. Even if the Kano categories can enhance designers' understanding of customer needs, they are short as concrete decision criteria. So, considering resource limitations, managers are called to understand the priorities of improving the performance of these quality attributes. The described Kano model is useful to place the customer needs in each one of these categories and has been proven to be very important for a better understanding the customer needs. Nevertheless, it still isn't able to determine how much the partial or complete absence or fulfillment of a customer need impacts its overall satisfaction [24]. To deal with this situation, [PERSON] and [PERSON] [24] proposed a modified Kano model. Their model works, in general terms, the same as the original model, except for two aspects:  
* _Inclusion of an influence table:_ The inclusion of this table is directly linked with the Kano evaluation table (Table 3). The objective of this table is to determine the influence of each one of the Kano table cells on customer satisfaction. It is important to point out that though cells ((2.5--expect, dislike), (3.5--neutral, dislike), (4.5--live with, dislike)) are in the must-be category, their influence on customer satisfaction is different, considering that cell ((3.5--neutral, dislike)) is the pure state of a must-be feature. On the other hand, it can be said that cells ((2.5--expect, dislike) and (4.5--live with, dislike)) as not being the pure state of the must-be feature, their influence on their satisfaction will not be the same as the cell ((3.5--neutral, dislike)).