The outbreak of COVID-19 (coronavirus disease 2019) has become the focus of attention in the field of urban geography. Built environment, such as the layout of public spaces like transportation hubs and urban open spaces, is an important factor affecting the spread of the epidemic. However, due to the different behavior patterns of different age groups, the intensity and frequency of their use of various built environment spaces may vary. Based on this, we selected patients that were infected, with a non-manipulated time period, and the classification of human behavior patterns; we then conducted a regression analysis study on the spatial distribution and building environment of these COVID-19 patients. The results showed that the spatial distribution of young and middle-aged patients (18–59 years old) was more homogeneous, while the spatial distribution of elderly patients (60 years old and above) had a strong clustering characteristic. Moreover, the significant built environment factors exhibited in the two populations were extremely different. More diverse urban facilities and public spaces exhibited influential properties for older patients, while middle-aged and young adults were more influenced by commuting facilities. It can be said that the built environment shows different influences and mechanisms on the transmission of respiratory infectious diseases in different populations. Therefore, the results of this paper can inform decision makers who expect to reduce the occurrence of urban respiratory infectious diseases by improving the urban built environment.

No abstract

Based on the mode of manufacturers dominating in the forward supply chain and retailers dominating in the backward supply chain, a hybrid leading closed-loop supply chain structure with different two-way dominance is constructed to study the advantages and disadvantages of supply chain decision-making under logistics self-supporting and logistics outsourcing modes. Stackelberg game theory is used to solve the equilibrium solution and optimal profit of the forward and backward supply chains under different logistics modes. On this basis, the profits of manufacturers and retailers in the forward and backward closed-loop supply chains are compared, and finally, the conclusion is verified by numerical examples. The influence of different logistics modes on pricing decisions of manufacturers and retailers is studied based on the dual-agent hybrid dominant supply chain model, and then, the logistics mode selection of manufacturers and retailers under different conditions of forward dominant body and backward dominant body.