TY - JOUR AU - Zhou, Hao AB - 1. Introduction Eco-cities, which pour effort into eliminating the overall carbon footprint of the city whilst helping the humans and the nature to coexist aiming towards sustenance and sustainability [1]. Eco-cities have witnessed rapid growth in these years worldwide [2,3]. As the Eco-cities entering operation stage gradually, more and more researchers have found that users (who are living or working in the Eco-cities) satisfaction is one of the most important factors to determine the success or failure of Eco-cities. Kitakyushu eco-city is recognized the most mature model Eco-city project in Japan. The KPIs (key performance indicators) of this project are considered successful based on the quantified data of residents’ satisfaction degree, which indeed improved conditions for the aging population of this city [4]. Another well-known example of Eco-city is Sino-Singapore Tianjin Eco-city (SSTEC) of China, which generally accepted as the flagship project in China and one of the most successful Eco-cities in the world [5,6]. The construction and operation efforts of this Eco-city have been mainly put into aspects which residents able to truly experience, such as natural environment, man-made environment and life style [4,7]. By contrast, one of the key reasons why Masdar city (Abu Dhabi, UAE) and Dongtan city (Shanghai, China) considered as failure projects, is that both of them placed too much emphasis on realization of zero-carbon, and mandated the residents to adjust with lesser ‘comforts’ than they are used to [8,9]. Therefore, it is very important to investigate the user demands to attract more citizens willing to live or work in the Eco-cities, which will make the development of Eco-cities more sustainable and solid. Caprotti et al. [10] carried out fifteen interviews with the residents in Sino-Singapore Tianjin Eco-city of China in terms of the lived experiences, and found that social sustainability need to be paid more attention. Liu et al. [11] utilized Structural Equation Model (SEM) to investigate the residents’ repurchase intention of Green Residential Building (GRB) in Eco-city of China. Marciniak et al. [12] conducted structural interviews with the visitor perception of informal green spaces in Poland and concluded that informal green spaces are important complementary to formal green spaces in the city. To examine residents’ WTP (willingness to pay) for GRBs (green residential buildings) and its determinants, Liu et al. [13] conducted a survey among 511 current GRB occupants living in Sino-Singapore Tianjin Eco-city in China, and latent class regression was used to analyze the heterogeneity of their preferences. Sun et al. [14] collected the social media data, by applying the artificial intelligence technique to analyze the visitor responses to the green and open spaces in Shenzhen, China. Friederike et al. [15] conducted a quantitative questionnaire survey among people aged 50 years and older throughout the city of Berlin, to explore the older people’s urban green space visitation patterns. Erik et al. [16] used a discrete choice experiment to explore people’s preferences and willingness to pay for green features in an urban Neighborhood Management development zone in Berlin. Monteiro et al. [17] investigated the citizen demand of sustainability for urban forests based on i-Tree Eco surveys. The above recent researches on user demands investigation and analysis in the Eco-cities mainly focused on understanding the user need itself, yet lack of research on the relationship between the user demand and user satisfaction. Because improving the user (citizen who lives or works in the Eco-city) satisfaction will be the ultimate purpose of construction and operation of the Eco-city, yet user demands survey is just the process. Actually, the classification of user demands are various, same efforts to different classification of user demands may lead to different degree of satisfaction. In other words, different classification of user demands in Eco-city may need different strategies to satisfy. Therefore, an analysis method on revealing the relationship between user demands and user satisfaction was initially introduced to research field of Eco-city in this paper. The Kano model is a famous and important theoretical and quantitative model for the research of customer satisfaction towards product quality attribute [18] for different industries. Aliyu et al. [19] utilized integration method of Kano model and quality function deployment (QFD) to investigate the user demands for sport earphone. Wu et al. [20] conducted a study adopted Kano two-dimensional quality model to investigate the users’ needs on twenty service attributes of rehabilitation buses. Juan et al. [21] exploring sustainable planning strategies for public housing in Taiwan, the Kano model was adopted as a theoretical base. Ma et al. [22] used Kano model to differentiate between future vehicle-driving services demands. Xu et al. [23] presented a requirements analysis method based on Fuzzy Kano Model, which to improve the quality of virtual reality interior design software. Yao et al. [24] conducted the Kano model analysis of features for mobile security applications to gain more customer satisfaction. Chen et al. [25] investigated pharmaceutical logistics service quality with refined Kano’s model involving 104 respondents from medical institutions. Zhang et al. [26] studied on enhancing readers’ satisfaction model of electronic service quality in library based on LibQUAL+ and Kano model, and result shows that the model they built is feasible through the empirical analysis. However, for the research field of Eco-city, existing studies do not involve the Kano model to explore user (citizen who lives or works in the Eco-city) demands and the affection for the user satisfaction to date. This paper aims to initially introduce the Kano model analysis method to the research field of user demands and satisfaction in terms of the Eco-city, intends to explore the relationship between the user demands and user satisfaction. Based on the Kano model, the user demands classification and importance for the Eco-city can be defined accordingly. The user demands analysis method of Eco-city proposed in this paper, can be used for other researchers worldwide to investigate and quantitively analyze user demands according to their local development situation and preference of Eco-city. The user demands analysis results obtained through this method, can benefit different stages of Eco-city. For the planning and design stage of Eco-city, user demands analysis can help avoid ‘empty city’ phenomenon after construction, so as to save huge amount of fund and time. Because the construction of Eco-cities is extremely complicated and time-consuming, the developing organization of Eco-city needs to allocate limited resources investing in facilities and services of more critical user demands. For the operation stage of Eco-city, user demands analysis can help conduct POE (Post Occupancy Evaluation) process, in order to reveal aspects that residents dissatisfied in terms of operation and management of Eco-city. The O&M organization of Eco-city will be able to undertake relevant renovations accordingly regarding facilities and services to maximize user satisfaction. 2. Materials Since the Chinese national standard "Assessment Standard for green eco-district" (GB/T 51255–2017) [27] has been promulgated and implemented, the standard has strong authority, a large number of credits, and rich evaluation content. Therefore, the user demands library had been proposed based on the national standard. Regarding the national standard "Assessment Standard for green eco-district", from the perspective of evaluation dimensions, it mainly includes government management dimension and user dimension. For example, the credit "4.1.1 urban planning should meet the urban and rural planning requirements of the region." It can be classified as the content of government management dimension. The credit "4.2.5 Public service facilities in residential areas has better convenience." can be classified as the content of user dimension, which reflects the actual needs and expectations of the people for an Eco-city. Therefore, this article had started from the user dimension, combed and categorized the content of the national standard "Assessment Standard for green eco-district" (GB/T 51255–2017), and initially summarized the user demands library including six major categories. The categories are land use, ecological environment, green building, energy utilization, green transportation and humanities, including 25 specific user demands, which are shown in Table 1. Download: PPT PowerPoint slide PNG larger image TIFF original image Table 1. User demands library in Eco-city (Source: Authors, 2020). https://doi.org/10.1371/journal.pone.0248187.t001 3. Methodology China’s new urbanization process and the implementation of green development policies have jointly promoted the development of the Eco-cities. With the construction and operation of the Eco-city, user demands are constantly changing. According to the actual needs of users and feedback of problems encountered in the operation process, the Eco-city shall be continually improved and updated, and the functions and services need to meet user demands accordingly. In order to specifically understand the real demands of users in the operation of the Eco-city, and to improve the service quality, thereby enhancing the happiness index of users. The research process undertaken in this paper was as follows. Firstly, the user demands classification analysis for Eco-city based on Kano model was researched, including the questionnaire method and computation formula. Secondly the user demands importance analysis for Eco-city was studied. AHP method was adopted to obtain the initial weights of user demand items. Then weight adjustment was conducted based on the Kano demand category. Consequently, the final ranking of user demands importance was determined accordingly. At last, two Eco-cities in Tianjin and Chongqing city of China were selected to apply the methodology as case study. See Fig 1 for an illustration of the research process undertaken in this article. Download: PPT PowerPoint slide PNG larger image TIFF original image Fig 1. Illustration of the research methodology undertaken in this article. (Source: Authors, 2020). https://doi.org/10.1371/journal.pone.0248187.g001 3.1. User demands classification analysis of Eco-city based on Kano model 3.1.1. Introduction of the Kano model. The Kano model was an important theoretical model which was initially proposed by Japanese quality management professor—Noriaki Kano in 1984 aiming to illustrate and identify quality attributes for the research of customer satisfaction [18]. Kano model provides a framework which could enable the elicitation of product requirements. It helps increase customer satisfaction if the elicited requirements are met [23]. Kano model not only could be used for requirement clarification in the early stage, but also for different stages in the service delivery lifecycle. Kano survey helps to add value by focusing efforts in service design, development and verification stages to encompass features on use case level, supported by early prototypes and conducted with real customers [24]. Compared with other models, the Kano Model does not assume the existence of a linear relationship between product/service performance and customer satisfaction. Kano noticed that customers’ requirements are not equivalent and that some requirements, in fact, are capable of generating more satisfaction than others. Moreover, customer satisfaction is not always proportional to the functionality of the good, which implies that higher quality does not necessarily lead to higher satisfaction for all product attributes or services requirements [28]. The customer satisfaction over specific quality of a product or service may vary with customer’s preference over the quality attribute as shown in Fig 2 [18]. The X -axis stands for the level of quality performance (from Insufficient to Sufficient) and the Y -axis represents the customer satisfaction level (from Dissatisfaction to Satisfaction). There are 5 quality attributes in Kano Model as follows [29]: One-dimensional quality (O): Customer is satisfied when this quality attribute is sufficient and vice versa. Customer satisfaction level is in liner relation with quality attribute adequacy. Attractive quality (A): Sufficiency of this quality attribute will lead to more satisfaction of customer, yet not cause dissatisfaction with the absence of this attribute. Must-be quality (M): Customers tend to consider this quality attribute for granted. Which means improving this attribute will not result in more satisfaction, but the customer will become very dissatisfied if this quality attribute not provided. Indifferent quality (I): Whether this quality attribute sufficient or not, will not affect customer satisfaction. The customer is not interested with the product or service quality. Reverse quality (R): Customer does not desire this product attribute and also expects the reverse. Download: PPT PowerPoint slide PNG larger image TIFF original image Fig 2. Relationship between product quality and user satisfaction of Kano model (Kano et al., 1984 [18]). https://doi.org/10.1371/journal.pone.0248187.g002 3.1.2. The questionnaire of Kano model. A questionnaire can be constructed according to Kano model [30]. The questionnaire consists of questions about the functional requirements of a product. Each functional requirement consists of two inverse questions, one functional and one dysfunctional. For example, for the functional question, the customer (user) might be asked “If there are sufficient service facilities around the residential area, which are very convenient and accessible, how do you feel?”. For the dysfunctional question, the customer (user) might be asked “If there are insufficient service facilities around the residential area, which are not convenient and accessible, how do you feel?”. Each functional and dysfunctional question has five possible answers, (1) I like it that way; (2) It must be that way; (3) I am neutral; (4) I can live with it that way; (5) I dislike it that way. 3.1.3. User demand category analysis of Kano model. The form shown in Table 2 can be utilized to evaluate the quality attribute category of demand by each customer (user), including One-dimensional (O), Attractive (A), Must-be (M), Indifferent (I), and Reverse (R). “Q” represents unusable response which will be eliminated. Then all the Kano categories for each demand item of all customers (users) are summarized to determine the final Kano category for each demand item, with adopting the principle of relatively majority [31]. Download: PPT PowerPoint slide PNG larger image TIFF original image Table 2. Kano evaluation form for quality attribute category (Source: Authors, 2020). https://doi.org/10.1371/journal.pone.0248187.t002 3.1.4. Computation of CS and DS of Kano model. After collecting all the responses from customers (users) towards each demand item in terms of the Kano category (One-dimensional, Attractive, Must-be, etc.), it is possible to calculate two coefficients, namely customer satisfaction (CS) and customer dissatisfaction (DS) [30]. The customer satisfaction coefficient has a value between 0 and 1 (values close to 1 represent great satisfaction while values close to 0 indicate low satisfaction). The customer dissatisfaction coefficient has a value between -1 and 0 (values close to -1 represent great dissatisfaction while values close to 0 indicate low dissatisfaction). The calculated equations are as follows: When Ai, Oi, Mi, Ii stands for the number of Attractive, One-dimensional, Must-be, and Indifferent attribute respectively of demand item i. 3.2. User demands importance analysis of Eco-city based on Kano model 3.2.1. The questionnaire of user demands importance. The user demands survey questionnaire of Kano model can carry out qualitative analysis of classification for each demand. However, to understand the comprehensive importance of each user demand in detail, further user surveys are needed. Therefore, Likert five-point scale method was used for the importance survey questionnaires, setting "very unimportant", "relatively unimportant", "generally important", “relatively important” and "very important" for each user demand item [32]. These five levels correspond to scores of 1, 2, 3, 4, and 5 respectively. The importance questionnaire sample form of user demand in Eco-city indicates as follows in Table 3. Download: PPT PowerPoint slide PNG larger image TIFF original image Table 3. The importance questionnaire sample form of user demand in Eco-city (Source: Authors, 2020). https://doi.org/10.1371/journal.pone.0248187.t003 3.2.2. Determination of initial weight. The most mature AHP (Analytic Hierarchy Process) method [33,34] in the industry was used to determine the initial weights of the importance of 25 user demands in the Eco-city. This method can summarize different factors related to decision-making, and perform qualitative and quantitative evaluation [35,36]. When using this method for calculation, the judgment matrix needs to be constructed firstly. The way to construct the judgment matrix is: calculate the average score of each analysis item, and then divide the average score for two items successively to form judgment matrix. For the user demands importance analysis of eco-city, 25-order judgment matrix was constructed (because 25 user demand items in the survey). After summarizing the results of importance questionnaire for eco-city, the average score for each demand item was calculated, and the judgment matrix was shown in Table 4 (as the whole matrix was too large, only 10-order matrix shown for demonstration). Download: PPT PowerPoint slide PNG larger image TIFF original image Table 4. Judgment matrix for user demand items of Eco-city (Source: Authors, 2020). https://doi.org/10.1371/journal.pone.0248187.t004 The judgment matrix analysis used to get the eigenvector and initial weight of each user demand item. Then a consistency test should be conducted. The maximum eigenvalue according to the vectors of matrix needs to be calculated, and the maximum eigenvalue utilized to get the CI (consistency index = (maximum eigenvalue–n)/(n-1)). RI (Random Consistency Index) can be referred to Table 5 according to the order of matrix (For example, the RI of 25-order matrix is 1.6556). Download: PPT PowerPoint slide PNG larger image TIFF original image Table 5. Random consistency index (Source: Saaty, 2008). https://doi.org/10.1371/journal.pone.0248187.t005 Finally, a consistency test is needed to calculate the CR (consistency ratio = CI/RI). Under normal circumstances, the smaller the value obtained by CR, the better, because this represents better consistency of the key calculation matrix and the normalization. Generally speaking, the value of the calculated correlation matrix should not be greater than 0.1 [34]. 3.2.3. Weight adjustment of user demand items based on Kano model. Initially, the user’s awareness is the only way to determine the initial importance, and it is difficult for users to notice the impact of their own needs on satisfaction, which leads to the great limitations of this evaluation method. Through the analysis of user feedback after the return visit, it is found that most users will emphasize their essential functions when using them, or hope that the product can increase the actual functions they need, but almost no users express their needs for attractive attributes. Attractive attributes can bring unimaginable parts to users in the subconscious to increase their satisfaction, which is an aspect that users often overlook when using products [37]. Therefore, in the final weight analysis, the initial weight of the user demand item cannot be directly used to analyze the importance of the user demand item. It is also necessary to consider whether the demand item is helpful for improving user satisfaction. This paper adjusted the initial weight of each demand item based on the theory of the Kano model, so as to obtain the final weight of user demand in the Eco-city [38]. The adjustment formula is as follows: Where wi—Initial weight of user demand item i; —Final weight of user demand item i; mi—Kano classification adjustment coefficient of user demand item i; When the user demand item classified to Attractive attribute, m>1; When the user demand item classified to One-dimensional attribute, m = 1; When the user demand item classified to Must-be attribute, 01; When the user demand item classified to One-dimensional attribute, m = 1; When the user demand item classified to Must-be attribute, 01; When the user demand item classified to One-dimensional attribute, m = 1; When the user demand item classified to Must-be attribute, 0