Government subsidy and benefit distribution mechanisms for transportation PPP projects: An evolutionary game perspective.

Public-private partnerships (PPP), as an important model for collaboration between the public and private sectors, is an urgent and critical topic due to the serious financial losses of governments involved in transportation PPP projects in recent years. Current research focuses on the government subsidy model, in which the effective implementation of government subsidies relies on the design of incentives for stakeholder behavior. Although the positive externalities are strong, they are prone to the problem of "free riding," which leads to low project performance and challenges in compensating for the government's financial losses. Therefore, this study proposes a novel dynamic subsidy mechanism that can be adjusted based on actual changes in transportation demand and that is linked to project performance. We use evolutionary game theory to construct a two-party evolutionary game model of the government and social capital, focusing on the stability and influencing factors of these interactions. Our research unveils that reaching specific thresholds in both the incentive coefficient and benefit distribution ratio induces an "positive management-negative management" shift in the behavior of involved parties, leading to enhanced project outcomes. Notably, fluctuations in operational quality substantially enhance the efficiency of the active management of private sector, with no discernible impact on the subsidy efficiency of the government. Therefore, our study provides a theoretical framework for improving the revenue allocation and government subsidy mechanism, which has theoretical and practical implications for enhancing the effect of government incentives and improving the quality of operational social capital.

Municipal household solid waste collection strategies in an African megacity: analysis of public private partnership performance in Lagos.

Managing municipal solid waste is a pervasive urban problem globally. While several strategies have been applied for efficient municipal solid waste management in developing economies, their performance level has not been critically investigated. Among these strategies, the public private partnership has widest appeal. This study examines the performance of public private partnership in household solid waste collection in Lagos, Nigeria. We collected primary data using a municipal solid waste survey in three residential density areas of Lagos megacity. Descriptive and inferential statistics were used to analyse the data. Two indexes of service performance, namely the service reliability index and operational quality index, were created to produce evidence on public private partnership performance in municipal solid waste collection in Lagos. Results show that the average amount of household solid waste generation per week ranges between 22.75 kg in the medium residential density area and 30.39 kg in the high residential density region of the city. The estimated per capita waste generated in Lagos Megacity is 0.95 kg day(-1). Regression models indicate that the public private partnership performance is significantly influenced by economic status, affordability, flexibility, consistency, cleanliness, coverage and accessibility, as well as number of waste collection vehicles, vehicle maintenance, capacity, trip rate, frequency, number of personnel and quality of personnel. Findings from this study reveal that Lagos residents have strong positive perception of public private partnership as a waste collection policy framework. The study has important policy and practical implications for urban waste management, public health and sustainability in developing economies.

Design of a trichogramma balls UAV delivery system and quality analysis of delivery operation.

The field boundaries in our country are complex. In attempts to control pests via trichogramma-dominated biological control, the long-term practice of manual trichogramma release has resulted in low control efficiency, thereby impeding sustainable agricultural development. Currently, the novel approach involves utilizing Unmanned Aerial Vehicles (UAVs) for trichogramma balls delivery; however, the system is still in its nascent stages, presenting opportunities for enhancement in terms of stability and accuracy. Furthermore, there is a notable absence of comprehensive operational quality assessment standards. In this study, we establish a stable and accurate trichogramma balls delivery system using a four-axis plant protection UAV and introduce a comprehensive evaluation method for trichogramma balls delivery system. When dealing with fields with complex boundaries, it is beneficial to divide them into rectangular, trapezoidal, and stepped small fields at the boundary and perform operations within these small fields. According to our proposed evaluation method, when only considering the effect of field operations, the most effective boundary division shape is trapezoidal, followed by rectangular. and the worst is stepped. If both field operation effectiveness and the utilization effect of placed trichogramma balls are considered, the optimal shape is trapezoidal, then stepped, with rectangular being the least effective. Consequently, for UAV sub-area operations in complex boundary fields, it is advisable to divide the boundaries into trapezoids wherever possible. Field experiment results indicate that the system's delivery area can reach up to 4158 m²/min and the coverage rate of released trichogramma balls can exceed 97%. The system design methodology and comprehensive operational quality evaluation method proposed in this article provide technical support and scientific basis for the application and promotion of UAV delivery trichogramma balls system. This is conducive to the high-quality development of agriculture.