With the increasing frequency of emergencies in recent years, the emergency response capacity of the emergency management system needs to be improved. Based on safety stock strategy, this paper proposes a multilevel siting model on the topic of mobile emergency response. We modeled the emergency response needs during emergencies by incorporating the population distribution of each region. The uncertainty of emergencies is modeled by aggregating the frequency of crises in each region over the past 20 years. The site selection model minimizes contingency logistics costs that include transshipment, deployment, inventory, and safety stock costs. In this paper, the IA (Immune Algorithm) is optimized to solve the constructed emergency site selection model. The experiments on the model were carried out with data from the area of Chongqing, Sichuan Province. The number of logistics centers and distribution storage warehouses was tested. The influence of safety stock strategy on the total cost of emergency logistics was analyzed. The research results found that the cost of safety stock is negatively related to the cost of transshipment. In addition, the total cost of emergency logistics has a lower bound. Adding distribution and storage warehouses does not further reduce the total emergency logistics cost.

Existing research has neglected to explain why freemium business models lead to differentiated performance or what accounts for the difference in their revenue models. This study investigates how the configuration effect of freemium business models promotes performance and explores the different ways through which freemium business models, their dynamic capabilities, and environmental uncertainty interact to achieve high performance. The fuzzy set qualitative comparative analysis (fsQCA) approach was used to test the conceptual model with data from 45 freemium business model apps. From empirical evidence on the relationship between freemium business models, dynamic capabilities, and environmental uncertainty, the study finds that (1) bundled and fragmented freemium business models are fundamental performance drivers. However, they work only in combination with dynamic capabilities and environmental uncertainty. Moreover, the bundled and fragmented freemium business models have complementary rather than substitution relationships. (2) For companies with bundled and fragmented freemium business models, high sensing and seizing capabilities are critical to achieving high performance. A high bundled freemium business model, high sensing capability, and a lack of fragmented freemium business models and seizing capability can lead to high performance, regardless of reconfiguration capabilities and environmental uncertainty. (3) Under high environmental uncertainty, offering fragmented freemium business models with or without a bundled freemium business model will lead to high performance if they have high sensing, seizing, and reconfiguring capabilities. This study can provide systematic decision support for achieving high performance through freemium business models and the configuration of dynamic capabilities under environmental uncertainty.

Compared with the traditional operation mode of emergency vehicles, the mobile emergency vehicle is regarded as a new type of emergency facility carrier with the features of variable locations, flexible mobility, and intelligent decision-making. It can provide an effective solution to reasonably respond to the uncertain risks of sudden disasters. Focusing on meeting the maximum demand for materials and services in disaster areas, this paper proposes a scheduling model of mobile emergency vehicles with dual uncertainty of path and demand. The model, solved by an integer-coding hybrid genetic algorithm, aims to obtain minimum mobile emergency scheduling cost and time by transforming the multi-objective problem into a single-objective problem. The “5.12” Wenchuan earthquake is used as an example to validate the model and solving method. The results show that the model can reduce the impact of uncertain risks and improve the scientific logic of emergency strategies and deployments based on the actual crisis scenario. It benefits from introducing mobile emergency vehicles and optimizing their scheduling process.