THE "DATABASE-NETWORK-FLOW-SPECTRUM-LAW" THEORETICAL FRAMEWORK FOR URBAN SAFETY CHARACTERIZATION BASED ON "RISK SOURCE" + "RISK EXPOSURE" + "MITIGATION FACTOR"

The urban safety in China is faced with many major challenges such as natural disasters and incidents. To meet the practical needs and to solve the important issues in urban safety at the current stage, the theoretical framework for characterization of urban safety is proposed. First, the concepts of "mitigation factor" and "mitigation capacity" are introduced into the framework. Then, taking the so-called "risk source", "risk exposure" and "mitigation factor" as the fundamental components, the Database-Network-Flow-Spectrum-Law theoretical framework is proposed, in which the advantages of new technologies (e.g., digital twin, knowledge graph and machine learning) are considered. The concept and key issues of the five stages of the framework are elaborated. The proposed theory is expected to characterize the capability of city managers in urban safety more reasonably, to help realizing the dynamic characterization of urban safety performance, and to provide an intelligent learning approach and an optimization method for management decisions.