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Low-altitude airspace is developing rapidly, but the utilization rate of airspace resources is low. Therefore, in order to solve the problem of the safe operation of the fusion of large UAVs and manned aircraft in the same airspace, this paper analyzes the theoretical calculation of the collision risk of the fusion operation of manned aircraft and UAVs at Feng Ming Airport in Zigong, verifying that while assessing the safety spacing of 10 km in the lateral direction, it further simulates the possibility of calculating the theoretical smaller safety spacing. The study will propose a new theory of error spacing safety margin and improve it according to the traditional Event collision risk model, combining the error spacing safety margin to establish an improved collision model more suitable for the fusion operation of manned and unmanned aircraft and reduce the redundancy of calculation. The error factors affecting manned and unmanned aircraft at Zigong Airport are analyzed, and theoretical calculations are analyzed by combining the actual data of Zigong Airport. Finally, the Monte Carlo simulation method is used to solve the error, substitute the calculation results, and simulate a section of the trajectory of the fusion operation for the reverse argument. The theoretical calculation results show that the collision risk from 10 km to 8 km satisfies the lateral target safety level (TSL) specified by ICAO under both traditional and improved models. The collision risk calculated by the improved model incorporating the error spacing safety margin is smaller, which enhances the safety of the model calculations. The results of the study can provide theoretical references for the fusion operation of manned and unmanned aircraft. [ABSTRACT FROM AUTHOR]

Ecological infrastructure plays a crucial role in strengthening the relationship between humans and the environment by optimizing ecological space and resource allocation in urban environments. However, there are few studies on the functional assessment and spatial and temporal evolution of ecological infrastructure and its layout optimization. In this study, we developed an ecological infrastructure optimization method based on ecosystem service supply, demand, and flow in Yantai City as the study area; identified the spatial extent of urban ecological infrastructure and its spatial and temporal changes based on the spatial quantification of multiple ecosystem services; assessed whether the existing ecological infrastructure could satisfy the needs of the urban residents by calculating the ecosystem service supply and demand indexes; and used the spatial quantification of ecosystem service flows to optimize the spatial layout of urban ecological infrastructure. This study shows that, from 2010 to 2018, ecological infrastructure in Longkou, Zhaoyuan, and Laiyang decreased, contrasting with the growth in the existing peripheral areas. The study found a clear spatial mismatch between the supply and demand of ecosystem services, especially in the central urban areas, suggesting that the existing infrastructure was unable to satisfy the needs of high-demand areas. This study assessed the peripheral areas of the city using comparative ecological radiation force (CERF), including 314.64 km2 of environmentally beautiful village units as key components of ecological infrastructure in Yantai City. These findings are crucial for sustainable environmental management and urban development strategies. [ABSTRACT FROM AUTHOR]

It is vital to conduct urban ecosystem service evaluations and demarcate ecological management zoning to preserve regional ecological security and the spatial optimization of urban functions. This study assessed and examined the spatial distribution characteristics of the supply and demand of five typical ecosystem services in Zhengzhou and their matching pattern. Based on Maslow's hierarchy of needs, urban ecological management zoning was demarcated to guide the spatial optimization of urban functions. The results showed that most of the ecological goods and services in Zhengzhou were generally provided in the west and south of the city. High-value areas of ecosystem service demand were mainly found in the urban center. There was a definite circle structure of total ecosystem service demand. Carbon sequestration, grain production, water yield, and habitat maintenance in the urban center area indicated an ecological deficit. Soil conservation in most regions was a surplus trend. Zhengzhou was demarcated into five groups of ecological management zoning. Different preferences had an impact on the ecosystem service supply and demand. The rise in living conditions led to an increase in the demand for high-level ecological services. This study can provide an essential theoretical basis and practical assistance for urban space optimization and ecosystem service management. [ABSTRACT FROM AUTHOR]

The rapid urbanization and population growth in China have brought the issues of social equity and justice to the forefront. The supply and layout of public service facilities play a crucial role in determining the residents' quality of life and have become a significant factor triggering social equity and justice concerns. This study took Zhengzhou's urban core as an example. From the perspectives of regional equality, spatial equity, and social justice, the service area analysis and Gaussian two-step floating catchment area method were used to analyze the public service facilities' layout situation and the equity and justice issue and to discuss the causes of the current situation. The study found that the social equity and justice of public facilities in Zhengzhou's urban core were more prominent. The accessibility of public facilities inside and outside the 3rd ring road of the urban core exhibited marked differences, indicating a need for improvement in regional equality and spatial equity. Vulnerable groups lacked special care and public facilities lacked justice. Combined with the development process of urbanization in Zhengzhou, this paper argued that this was closely related to the government's public policies. [ABSTRACT FROM AUTHOR]