*2.1. The Kano Model*

The Kano model divides demand attributes into 5 types, as shown in Table 2 and Figure 2 [31,32]. The *X*-axis represents the level of quality performance (from insufficient to sufficient) and the *Y*-axis represents the level of user satisfaction (from dissatisfaction to satisfaction), which can be divided into five categories. The must-be quality (M) means that when this factor is applied or improved, the user's satisfaction with the product will not be improved. If this factor is not considered or is weakened, the user's satisfaction with the product will drop significantly. This factor must be considered in product design. The indifferent quality (I) means that regardless of whether this factor is applied or not, the user's satisfaction with the product does not fluctuate, and this factor does not need to be considered in product design. The one-dimensional quality (O) means that when the factor is applied or improved, the user's satisfaction with the product is greatly improved. If the factor is not considered or is weakened, the user's satisfaction with the product will decrease accordingly. This factor is a competitive attribute and is an important factor in product design. The considered part is different from other conventional products and reflects unique, special, and high-quality characteristics. The attractive quality (A) means that when the factor is applied or improved, the user's satisfaction with the product is greatly improved. If the factor is not considered or is weakened, the user's satisfaction with the product does not change, and the factor can be developed within the scope of the cost. The reversal quality (R) means that when the factor is applied or improved, the user's satisfaction with the product does not rise but falls, and the user has no demand for the factor, which should be eliminated in the design.




**Figure 2.** Relationship between quality performance and user satisfaction of Kano types [31,32].

#### *2.2. Questionnaire Design Based on Kano Model*

The premise of the Kano model is questionnaire research. Functional questions and dysfunctional questions were set in the questionnaire. Functional questions aim to ask whether the user is satisfied if this demand is considered in the product design. The purpose of the dysfunctional question is to ask if the user would be satisfied if the product design left this demand out. Therefore, in the questionnaire design, a maximum of five demand/function questions should be set in the same questionnaire, and the keywords of the functional question and dysfunctional question should be bolded in different colors to prevent the questionnaire results from being affected by unclear questions. In addition, multiple-choice questions were utilized when setting the question type, avoiding using an array of questions and preventing the respondents from answering questions in confusion due to the small degree of distinction.

Therefore, the questionnaire developed in this study adopted the form of "Single choice + Multiple choice", combined with the interviews of pedestrians in shopping malls, to obtain three elements, including user's basic information, objective data, and subjective data about users related to indoor navigation in shopping malls. The questionnaire included the following three main parts, and the specific item settings are shown in Figure 3.

Part1: User's personal basic information, including gender, age, and occupation.

Part2: Objective data of users related to the indoor navigation of shopping malls, including the frequency of visiting shopping malls, the purpose of visiting shopping malls, the types of shopping malls visited, whether users are familiar with shopping mall maps, the types of shops they often visit, whether they can accurately find the shortest path, etc.

Part3: Subjective data of users related to the indoor navigation of shopping malls, including opinions and demands on indoor navigation in shopping malls, and satisfaction with existing indoor navigation signs/systems. Among them, the functional and dysfunctional questions for indoor navigation in shopping malls were combined with 5 general demands, including "Avoid crowded/emergency roads", "Passing by specific types of shops", "Bypass specific types of shops", "Vertical elevator first", and "Escalator first".

The sources references of the 5 general demands are shown in Table 3, which prove that the investigated functions cover most shopping mall users. The setting of functional and dysfunctional questions is shown in Table 4. The questionnaire respondents are allowed to fill in personalized needs in addition to the 5 general demands. Among them, because "Avoid congestion/emergency roads" involves quantitative analysis, the choice of indicators for the congestion environment was added to the questionnaire. We adopted results from Zhou et al. [29], which divided the congestion index into the traffic density index and the traffic speed index. The traffic density index (person/m2) was divided into four grades ([0, 0.75], (0.75, 2.00), (2.00, 3.50), and (3.5, +∞]). The traffic speed index (m/s) was divided into four levels ((1.40, +∞], (1.08, 1.40], (0.30, 1.08], and [0, 0.30]). Based on this, the questionnaire for this study was divided into multiple levels, and the traffic density index was divided into six grades (0.25 people/m2, 0.5 people/m2, 0.75 people/m2, 1.25 people/m2, 2 people/m2, and ≥2 people/m2). The traffic speed index was divided into four grades (1.5 m/s, 0.75 m/s, 0.3 m/s, and ≤ 0.3 m/s). In order to improve people's engagement with the questionnaire, pictures of the scene under different traffic densities were simulated (shown in Figure 4), which is analogous to the normal walking speed.

**Figure 3.** Main parts and specific items of questionnaire.




**Table 4.** Sample functional and dysfunctional questions of Kano questionnaire.

**Figure 4.** Pictures with the scene under different crowd densities.
