The ageing coefficient is selected as the index to evaluate population ageing, and some methods are proposed for analyzing differences in regional population ageing from temporal and spatial perspectives. China is used as the case study over the period 1998–2014. The concentration degree of the elderly varies regionally, but fluctuations in regional population ageing remain relatively stable. The coefficient of variation of population ageing fluctuates with an overall decreasing tendency. Population ageing in China exhibits a ladder-like distribution different from the distribution corresponding to economic strength. Spatial autocorrelation in population ageing is observed, with a comparatively steady spatial pattern.

Big data with a large number of observations (samples) have posed genuine challenges for fuzzy clustering algorithms, and Fuzzy C-Means (FCM), in particular. In this study, we propose an original algorithm referred to as a hyperplane division method to split the entire data set into disjoint subsets. By disjoint subsets, we mean that the data subspaces (parts of the entire data space), each of which is supported or spanned by the data points in the corresponding subset, do not overlap each other. The disjoint subsets turned out to be beneficial to improving the quality of the clusters formed by the clustering algorithms. Moreover, considering that either a large number (say, thousands) or a small number (say, a few) of clusters may be pursued in the clustering task, we propose corresponding strategies (based on the hyperplane division method) to make clustering processes feasible, efficient, and effective. By validating the proposed strategies on both synthetic and publicly available data, we show their superiority (in terms of both efficiency and effectiveness) manifested in a visible way over the method of clustering the entire data and over some representative big data clustering methods.

In the construction of urban infrastructure projects, the ecology, economy, and society of surrounding areas will suffer from negative influences, which will eventually be transformed into economic loss, thus social costs are formed. The current bid evaluation mechanism has not yet taken social costs into account, while the present bid evaluation model for construction projects has ignored experts' group character and fuzziness. Based on the review of literature, this paper attempts to apply the intuitionistic fuzzy group decision model to urban infrastructure projects considering social costs, and to establish the bid evaluation indicator system for urban infrastructure projects considering social costs. This paper introduces the intuitionistic fuzzy entropy, the relative entropy, the intuitionistic fuzzy cross entropy, the intuitionistic fuzzy hybrid averaging operator, and the intuitionistic fuzzy weighted averaging operator to solve respectively attribute (indicator) weights, expert weights, and the information aggregation existing in the bid evaluation of projects, as well as the optimization of the bid evaluation model of construction projects. Finally, the validity and scientific character of this model is investigated through a numerical example.Department of Building and Real Estat

As governments promote greatly the Public Private Partnerships (PPPs) to develop the Public Rental Housing (PRH) projects, the effective and efficient operation performance measurement should be pivotal for ensuring the success and sustainable development of these projects. Thus, this paper investigated operation performance indicators (OPIs) and measured the performance level of PRH PPP projects by fuzzy-analytic hierarchy process (AHP) comprehensive evaluation (FACE) method. Four important aspects of PRH PPP projects related to the operation performance and an evaluation indicator system of 21 OPIs from these four aspects were developed, the weights of which were calculated by using the AHP method. Based on fuzzy mathematics and the expert evaluation method, all the OPIs were quantitatively graded according to five ranks of evaluation criteria. Membership functions, weights of OPIs, and maximum membership degree principle were utilized to establish a multi-level FACE model for operation performance measurement of PRH PPP projects. One PRH PPP project of Nanjing, Jiangsu Province in China was chosen as the case study. Evaluation results were derived from the proposed model, and they generally conform to the actual situation. This study provides an effective operation performance measurement framework for PRH PPPs projects.

When COVID-19 wreaked havoc around the world and caused widespread panic, Chinese government has taken pandemic information disclosure measures to fight the outbreak. However, there is a theoretical debate about whether information disclosure increases or decreases panic of residents during a pandemic. In response to this debate, the authors conduct a questionnaire survey with 1062 participants in the worst period of COVID-19 in China. The results reveal that both generic information and detailed information disclosure can alleviate panic by enhancing individuals’ perceived prevention effectiveness and increase panic by amplifying individuals’ risk perception. In addition, information disclosure is more effective in reducing panic in conditions with a higher level of trust in local government. These findings provide practical evidence for the role of information disclosure in alleviating panic in a pandemic, and suggest that pandemic information timely disclosed by the local government is feasible to ease the spread of panic.