The outbreak of COVID-19 has rapidly become a global pandemic. It seriously challenges each country and government for its capacity and management of public health systems facing emergency. No single country can be an island that is immune to this pandemic, regardless of its geographic location, population profile, or status of economic development. What matters most to a country is the actions taken by the government to minimize the negative impacts of the whole society. Countries with different social structures, lifestyles and culture backgrounds tend to adopt different policies to contain the spread of COVID-19. Taking active control strategies to halt the spread of this pandemic at an affordable cost becomes imperative to every society and country. In this issue, our Managing Editor, Professor Baoding Liu of Tsinghua University, kindly assembles five novel studies on modeling COVID-19 from the perspective of uncertainty theory for our readers and the research community. FODM certainly appreciates Professor Liu’s special efforts.

中文翻译：

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编者寄语

COVID-19 的爆发已迅速成为全球流行病。它严重挑战每个国家和政府对面临紧急情况的公共卫生系统的能力和管理。无论其地理位置、人口状况或经济发展状况如何，任何一个国家都无法成为不受这一流行病影响的岛屿。对一个国家来说，最重要的是政府采取的行动，以尽量减少整个社会的负面影响。具有不同社会结构、生活方式和文化背景的国家倾向于采取不同的政策来遏制 COVID-19 的传播。每个社会和国家都必须采取积极的控制策略，以可承受的成本阻止这种流行病的传播。本期，我们的执行主编，清华大学刘保定教授，请从不确定性理论的角度为我们的读者和研究界收集五项关于建模 COVID-19 的新研究。FODM 当然感谢刘教授的特别努力。