This paper tackles the problem of intelligent connected vehicles platoon stability for the vehicle cooperative control system in the presence of communication interruption. Firstly, a vehicle platoon ...system is formulated into a third-order nonlinear dynamics model, in which the influence of the nonlinear terms is eliminated by using the feedback linearization method. Then, a novel cruise control strategy is developed by a minimum safe distance for switching from the Cooperative adaptive cruise control to Adaptive cruise control to deal with the communication interruption. Moreover, under the communication topology of a bi-directional leader following, an adaptive sliding mode controller is proposed in order to guarantee that 1) the spacing error of the vehicle platoon converges on a neighborhood of zero, whose fluctuation is also reduced, improving the traffic throughput; 2) A sufficient condition of the vehicle platoon stability is derived based on the frequency domain analysis method and the final value theorem. Finally, the numerical simulation of the proposed cruise control strategy and controller is conducted to validate the theoretical analysis.
This paper tackles the problem of connected vehicle platoon realistic control for the vehicle cooperative control system with the longitudinal nonlinear dynamics and parametric uncertainties subject ...to invalid communication. In the proposed cruise control strategy, a periodic event-triggered mechanism is designed to classify the invalid communication into packet losses and communication interruption so as to prevent frequently switching from cooperative adaptive cruise control mode to adaptive cruise control mode while also excluding Zeno behavior. The proposed adaptive robust control system guarantees that (i) the spacing errors of platoon vehicles rapidly converge to the neighborhood of zero, resulting in robust improvement of tracking performance; (ii) the closed-loop platoon control system is proved to be globally stable based on the Lyapunov stability theory by employing the eigenvalue decomposition method so that the synthesized distributed control law is low dimensional and independent of the length of vehicle platoon, avoiding extremely complex calculation. Additionally, the sufficient conditions for achieving string stability in a vehicle platoon are derived. Finally, numerical simulation results are given to demonstrate the effectiveness of proposed cruise control system subject to invalid communication.
At present, it is the most important period to achieve the dual carbon goal and China 's economic transformation. The Chengdu-Chongqing twin-city economic circle plan is an important national policy ...proposed to promote the high-quality economic development of western China. However, due to the influence of geographical location, the frequent natural disasters in the economic circle of Chengdu and Chongqing have become a problem that cannot be ignored in the process of economic development. Many studies have discussed the relationship between natural hazards and economic development or between resource utilization and economic development in megacities, but little attention has been paid to the relationship between the three in intra-city development. This paper takes three cities in Chengdu-Chongqing Economic Circle as examples. The environment-resource-economy related evaluation factors are selected from various aspects such as hazard, vulnerability, susceptibility and disaster prevention and mitigation capacity. And establish a suitable evaluation system for disaster risk assessment. At the same time, our study demonstrates the uniqueness of the study by taking different disasters in different regions as entry points. The results of the study show that, although the natural hazards that often occur in cities are not the same, there is a strong repetition of the characteristics that characterize the disaster (extreme) high risk areas. The occurrence of natural disasters has a significant impact on infrastructure, human safety and economic development and recovery in areas of high human activity. Moreover, the progress of energy conservation and emission reduction varies greatly among cities due to factors such as geographic location and natural resources, and there are still cases of uneven development, lagging industrial innovation and high dependence on energy for economic development. These results can help mega-city clusters to provide opinions on economic development, energy saving and emission reduction, disaster prevention and control, and other aspects. Provide reference for the government to rationally plan the economic and industrial layout in the future. Remind the relevant departments in high-risk areas that they should enrich emergency response measures and strengthen hazard screening. Improve disaster prevention and control capacity to reduce losses and promote the coordinated development of environment-resources-economy. This is of great significance and practical value for better understanding of the environment, utilizing natural resources, avoiding and mitigating losses from natural disasters, and realizing the dual-carbon goal.
•Analysis and research from different impact factors, evaluation of different types of disasters in different cities.•The high-risk areas of disasters in each city have the same characteristics.•The occurrence of natural disasters will inevitably have a great impact on economic development and recovery.•Small cities have limited resources and focus on the development of pillar industries, affecting planning and policies.•Cities still suffer from uneven development and lagging industrial innovation.
The mountainous areas in the western part of Sichuan Province are mostly Alpine Gorge regions with high mountains, steep slopes, complex topography and geomorphology, special climatic conditions, ...infertile soils, and fragile ecological environments. In this study, a geohazard risk assessment was carried out in the Alpine Gorge region to prevent geohazards from hindering socio-economic development, affecting the lives and safety of residents, and undermining sustainable development in the region. With the help of a geographic information system (GIS), the analysis of geohazard influence factors was carried out; eight indicators, such as elevation and slope aspect, were selected to construct the evaluation index system. Additionally, the time and space distribution pattern of each influence factor and geohazard was analyzed. Geologic hazards in the region are influenced mainly by precipitation and human engineering activities. The prediction and evaluation of geohazard risk in Jiulong County are based on the Information Value model (IV), the Logistic Regression model (LR), and the Random Forest model (RF). Comparing the Receiver operating characteristic (ROC) curves of the three models for the accuracy test, the results show that all three models are suitable for the Alpine Gorge region, and the Logistic Regression model has the highest accuracy. Based on the evaluation results, measures and countermeasures for geologic disaster prevention and mitigation are proposed in light of the reality of geologic disaster prevention and mitigation work in Jiulong County. The research results can guide the government’s disaster prevention and mitigation work, provide a scientific basis for formulating regional geologic disaster prevention and control strategies, and ultimately promote the region’s sustainable development.
This study presents a performance evaluation method of gas-fired heating and hot water combi-boilers. Seven factors related to the operation performance are selected. Twenty combi-boilers of ...different brands and heat input are selected randomly and tested according to GB25034-2010. The factor analysis and cluster analysis method are selected to evaluate the performance of combi-boilers. Analysis results show that, the evaluation model
F
= 0.652
F
1
+ 0.190
F
2
+ 0.158
F
3
is achieved, and the combi-boilers can be ranked with the evaluation model. The gas-fired combi-boilers selected can be copolymerized into 3 classes. The thermal efficiency at rated input in heating mode, thermal efficiency at 50% of the nominal input in hot water mode, concentration of O
2
and CO
2
of dry combustion products have the greatest impact on the operation performance of combi-boilers. This study provides a method for quantitative evaluation of the operation performance of combi-boilers and a clear direction for product optimization.
Two novel naphtho1,2-c：5,6-cbis（1,2,5-thiadiazole） and alkoxylphenyl substituted benzodithiophene based copolymers were developed as the donor materials for polymer solar cells. The resulting ...copolymers exhibit broad absorption bands in the range of 500--800 nm in thin films and deep highest occupied molecular orbital energy levels of-5.39 eV and -5.36 eV, respectively. The best device performance was achieved by PI, with an open-circuit voltage of 0.85 V, a short-circuit current density of 8.65 mA·cm^-2, a fill factor of 37.8%, and a power conversion efficiency of 2.78%.
With the implementation of the policy of expanding domestic demand, farmers have become the main body of rural economy and rural industrialization. Development of rural industrialization promotes the ...development of rural economy in China, effectively transfers the surplus labor force in rural areas, continuously optimizes the rural economic structure, improves the living standard of farmers, and has made important contributions to the stability and development of economy and society in China. This paper introduces the connotation of rural industrialization, classifies it into three modes according to the farmer’s investment and economic development, such as exogenous model of rural industrialization, endogenous model of rural industrialization and integrated model of rural industrialization. Though rural industrialization has obtained great achievements, there are still some problems restricting the development of rural economy in China. For instance, cognitive bias leads to the slow pace of rural industrialization; rural industry develops rapidly but its efficiency is low; intensive degree of economic growth is still very low; ability of independent innovation is weak; there are obvious contradiction between the constraints of resource and environment and the acceleration of industrialization; and development gap between regions has further widened. Therefore, policy suggestions are put forward. Firstly, continue to strengthen policy support. Secondly, take a new road of rural industrialization. Thirdly, strengthen the construction of human resources in rural areas. Fourthly, actively guide the investment behavior of farmers. And finally, support the specialty cooperative of farmers and the leading enterprises, which has certain reference significance to enhance agricultural benefit, farmers’ income, rural development and modern agriculture.
With the implementation of the policy of expanding domestic demand, farmers have become the main body of rural economy and rural industrialization. Development of rural industrialization promotes the ...development of rural economy in China, effectively transfers the surplus labor force in rural areas, continuously optimizes the rural economic structure, improves the living standard of farmers, and has made important contributions to the stability and development of economy and society in China. This paper introduces the connotation of rural industrialization, classifies it into three modes according to the farmer’s investment and economic development, such as exogenous model of rural industrialization, endogenous model of rural industrialization and integrated model of rural industrialization. Though rural industrialization has obtained great achievements, there are still some problems restricting the development of rural economy in China. For instance, cognitive bias leads to the slow pace of rural industrialization; rural industry develops rapidly but its efficiency is low; intensive degree of economic growth is still very low; ability of independent innovation is weak; there are obvious contradiction between the constraints of resource and environment and the acceleration of industrialization; and development gap between regions has further widened. Therefore, policy suggestions are put forward. Firstly, continue to strengthen policy support. Secondly, take a new road of rural industrialization. Thirdly, strengthen the construction of human resources in rural areas. Fourthly, actively guide the investment behavior of farmers. And finally, support the specialty cooperative of farmers and the leading enterprises, which has certain reference significance to enhance agricultural benefit, farmers’ income, rural development and modern agriculture.
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