Assessment methods of urban system resilience: From the perspective of complex adaptive system theory

With the continuous development of urbanization, and increasing uncertainties and risks, resilience has become an important criterion for urban safety. As a dynamic and open spatial system, the urban system presents typical complex features. Thus, the understanding of urban resilience from the perspective of complex systems theory is helpful to achieve a full understanding of the composition and functioning mechanism of urban systems, and to then improve the scientific nature of urban system cognition and research. In this article, the literature on urban resilience is first reviewed, and it is found that the related research on resilience assessment has yielded some assessment methods. Then, based on complex adaptive systems (CAS) theory and combined with its seven basic characteristics, the basic characteristics of complex urban systems are summarized from the perspective of the principle of the urban system action mechanism. On this basis, a framework of complex urban systems is constructed from three aspects, namely the system environment, system elements and system structure, and the assessment methods of the urban system resilience for each aspect are explored. This study not only expands the research on urban system resilience assessment, but also provides a reference for urban safety development and resilience improvement.