In order to clarify the correlation of eVTOL risk factors，and explore their impact on risk prevention and control in the UAM ecosystem，complex network theory was used to establish a risk evolution model. Based on the UAV accident database at home and abroad and the statistics of general aviation accidents，combined with the operation characteristics of eVTOL in urban low-altitude scenes，35 types of risk factors and 10 types of dangerous events were identified from the perspective of human-machine-environment. Gephi software was used to construct the network model，and the key nodes were evaluated comprehensively by the node degree，proximity centrality，internode centrality and PageRank(PR) algorithm. The key edges were evaluated by the internode number，so as to determine the key risk propagation path. In order to reduce the system risk，the measures to reduce the chain breaking disaster were proposed，and the system safety after chain breaking control was measured by network efficiency index. The results show that there are strong correlations among the eVTOL risk factors in the UAM ecosystem，and there are eight key risk transmission chains. The system safety is improved by 4.74%，16.21% and 18.10% by blocking key human factors，key system technical failure factors and key intermediate dangerous events，respectively.

In order to improve the accuracy of fire water cannon jet trajectory prediction and overcome the difficulty of traditional parabolic theory to describe the phenomenon that "when the initial velocity is constant，the range increases with the increase of jet flow"，first of all，the Euler method was used to establish a one-dimensional mass conservation equation along the trajectory of the water jet in the air，axial momentum conservation equations and the radial momentum conservation equations. Then，assuming that the axial velocity distribution of the water column and air column was in the shape of "bowler hat"，the established conservation equations were derived and analyzed，and the fire water cannon water jet trajectory calculation model was established. Finally，based on three conservation equations，the numerical computation process of the jet trajectory model was given and verified with the collected experimental data. The results show that the error of this model is less than 10%.

To advance environmental risk prevention and control in the Yellow River basin and achieve high-quality development，this study utilized air pollution，water pollution and carbon emissions to characterize environmental risk factors in this region. Firstly，the kernel density estimation method was employed to construct a kernel function，perform density smoothing，and analyze the spatial agglomeration patterns and evolutionary characteristics of environmental risk factors. Secondly，a spatial autoregressive model that accounts for spatial dependence was adopted to dissect the influences of multidimensional factors on environmental risk factors. The results indicate that air pollution，water pollution，and carbon emissions are primarily concentrated in the middle and downstream cities of Yellow River basin，delineating distinct regions for environmental risk prevention and control. Optimizing industrial structures and promoting green technological innovation in enterprises can reduce environmental risk factors. However，unreasonable energy conservation and environmental protection expenditures may lead to an increase in environmental risk factors. Furthermore，an inverted U-shaped relationship was observed between economic levels and population density and risk factors. From a long-term strategic perspective，regional collaborative governance and synergistic pollution reduction and carbon mitigation should be the strategic priorities. Strengthening cooperation among middle and downstream cities，optimizing industrial structures and increasing investment in industrial technological innovation are crucial steps towards achieving an economic development model transformation.

In order to address the difficulty to quantifying the emergency coordination ability of related organizations during the formation of urban flood emergency plans，a method to evaluate the robustness of inter-organizational networks for urban flood emergency response considering cascading failure was proposed. First，the inter-organizational networks for flood control emergency plans in Beijing，Shanghai and Shenzhen were established，and attack strategies and evaluation indexes of network robustness were proposed. Secondly，network characteristic statistical parameters are computed，and the network topology properties were analyzed. Then，the natural connectivity was selected as the robustness indicator to evaluate the network robustness under node single-attack strategy and continuous attack strategy. Finally，the robustness of networks under different attacks was compared，and the key organizations that have a great influence on robustness were found. The results indicate that inter-organizational networks of urban flood control emergency plans in Beijing，Shanghai，and Shenzhen have small-world and scale-free characteristics. Under single attacks of nodes，compared with the case of non-cascading failures，the robustness of inter-organizational networks is weaker considering cascading failures. Organizations with a large number of failure nodes are key to making the networks robust. Under continuous attacks，networks are strongly robust to random attacks，but weakly robust to deliberate attacks，where organizations with high degree values are key to making networks robust.

To address the issues of allocation of emergency rescuers，emergency rescue equipment，and disaster locations in the early stage of emergency rescue under the background of large-scale geological disasters，as well as improve the efficiency and quality of emergency rescue，an emergency rescue allocation decision-making method was proposed based on the three-sided matching theory. Firstly，the selection process among the three parties of emergency rescue was presented as a three-sided matching issue. Then，the multi-attribute preference evaluation information of the matching three parties was standardized，and a multi-attribute comprehensive preference score matrix was proposed. Furthermore，a three-sided matching stable and satisfactory model in the early stage of emergency rescue was developed to maximize system stability and total preference utility. Finally，the performance and accuracy of the proposed model were validated against cases. The results indicated that the proposed model reached reasonable matching between rescuers，emergency rescue equipment，and disaster locations in emergency rescue scenarios due to considering the effects of various parties' preferences on resource allocation. Furthermore，it can contribute to reducing the deployment time of emergency rescue operations and improve emergency efficiency and quality.

To investigate the development trend of occupational health of coal miners and promote the implementation of occupational health protection in coal mines. Based on the knowledge graph analysis method，CiteSpace software was used to conduct the keyword clustering and emergence of coal miners' occupational health literature included in the core databases of China National Knowledge Infrastructure(CNKI) and Web of Science(WoS) in the past 20 years. The results indicated that coal miners' occupational health research topics were divided into occupational health，occupational hazard factors，and career-related diseases. Occupational-related diseases focused on behavioral and physical diseases，cardiovascular and cerebrovascular diseases metabolic diseases，and chronic non-specific respiratory diseases. Compared with occupational diseases，occupational-related diseases had the characteristics of 'multiple causes and one effect'，causing much more difficulty in diagnosis. Pneumoconiosis，hearing loss，psychological stress，and hypertension were the main factors threatening coal miners' health. Moreover，such health issues were associated with occupational exposure，and risk analysis and control were important strategies to deal with hazard factors. The emerging research hotspots were the cause and prevention of occupational-related diseases，and the multi-discipline research of occupational health，brain science，and intelligence.

To improve the accuracy of miners' helmet-wearing recognition in coal mine underground operations，a helmet-wearing recognition algorithm was proposed based on human posture analysis and machine vision system optimization methods. First，Single Shot MultiBox Detector (SSD) was used as the basic model of multi-target identification. The squeezed neural network (SqueezeNet) was used to reduce the model parameters to develop an efficient recognition model，which improved the recognition accuracy of the miners' helmet and maintained the balance between the recognition accuracy and the calculation speed. Then，a multi-person posture estimation algorithm was used to locate the joint points of each miner and determine the miners' complex behavioral status. Finally，the upper limb nodes of the target were extracted based on fusion model of multi-target recognition and multi-person posture estimation，and then the helmet-wearing condition was determined by the spatial topological relationship between the upper limb nodes and the helmet frame. Moreover，3 000 pieces of image data were selected to validate the proposed method's performance. The results indicated that the machine vision system can optimize the hardware and software configuration to improve the system's performance. Furthermore，the identification accuracy reached up to 91.1%，which was much better than that of the latest helmet-wearing recognition algorithm. Therefore，the proposed system in this study can meet the requirements of helmet-wearing recognition accuracy for underground coal miners.

In order to clarify the connotation and governance path of metaverse safety & security and further enrich the theory of metaverse safety & security，the concept of metaverse safety & security was put forward based on a large safety & security pattern，and the basic features of metaverse safety & security were analyzed. Moreover，the governance path of metaverse safety & security was proposed. The results show that metaverse safety & security refers to the state or ability of the metaverse to reshape spatial and temporal stability，social civilization advancement and human well-being enhancement from the influence of unfavorable factors，and it has eight basic characteristics，namely，relativity，complexity，vibration，extensiveness，immediacy，relevance，publicity，and multidimensionality. Metaverse safety & security governance should integrate the development and safety & security of the metaverse，adhere to the principle of joint consultation and sharing，build a "technology-rule-society" trinity of governance models，and strive to enhance the digital safety & security capacity of the metaverse.

In order to improve the construction of undergraduate curriculum settings in the field of safety engineering，a total of 68 outstanding undergraduate theses (designs) from 38 universities in 2021 were collected and organized in this study. CiteSpace software was used to perform cluster analysis on the keywords of the theses，and the current research topics of undergraduate theses (designs) were clarified. Subsequently，the industry background of safety engineering in the 38 universities was investigated，and the differences of curriculums between representative Chinese and foreign universities in safety-related disciplines were statistically analyzed. The results show that the high-frequency keywords in the 68 theses are mainly related to the following aspects: "numerical simulation"，"disaster warning"，"safety management system" and "resilience". Based on the investigation results of the industry background of universities，among the 68 theses(designs)，the number of theses in the direction of public safety accounts for 45.6%，and the number of papers on mine safety accounts for 8.82%，but nearly 40% of the 38 universities take mine safety as a key service area，which showed that the research directions of safety disciplines theses has shifted from focus on industry safety to "general safety science". However，the characteristic curriculums still primarily focus on industry safety，with some repetition in the content of basic curriculums. Furthermore，there is a lack of numerical simulation curriculums. These factors make it difficult for the currently offered curriculums to support students in conducting their graduation projects. Additionally，compared with safety-related disciplines in foreign universities，it was found that the number of basic curriculums in safety engineering in China is relatively high，whereas the practical curriculums show the opposite condition.

In order to clarify the mechanism of safety and security incident causation from a safety and security intelligence perspective，and to consolidate the theoretical foundation for the investigation，analysis and prevention，and control of safety and security incidents from a safety and security intelligence perspective，research on safety and security incident causation model from a safety and security intelligence perspective was conducted. Firstly，according to the model for safety and security intelligence-safety and security behavior double loops，this paper analyzed the causes of safety and security incidents from a safety and security intelligence perspective. Secondly，the safety and security incident causation model from a safety and security intelligence perspective was constructed and explained. Finally，this paper analyzed the application of the safety and security incident causation model from a safety and security intelligence perspective with a safety and security incident on Line X of a city metro. The research shows that the safety and security incident causation model from a safety and security intelligence perspective is a safety and security incident causation system consisting of a safety and security intelligence loop and a safety and security behavior loop. According to this model，safety and security intelligence failures in the safety and security intelligence loop can lead to the disruption and collapse of the safety and security behavior loop of the system，resulting in a safety and security incident in the system.