Construction And Application Of The Event Evolutionary Graph On Public Emergencies

In recent years,public emergencies occasionally occurred in China,such as natural disasters,major public health events,major social security events and so on.The serious consequences did a certain degree of harm to the economy,society and the safty of people’s life and property.Therefore,it is crucial to understand the causes and consequences of public emergencies,formulate targeted strategies and policies,and further predict the occurrence of the same or similar events in this field.However,with the acceleration of China’s internationalization,modernization and urbanization,public emergencies has shown new characteristics,such as high frequency,large scale,difficult coordination and complex nature,which result in the exponential growth of the scale of news,network public opinion and user UGC data with public emergencies as the main and the difficulty of understanding,mastering and dealing with them.Therefore,the key and difficult issues in this field are figuring out the evolution rules of different categories of public emergencies in different periods,stages and circumstances,understanding the key causes and important consequences of the events,and proposing early warning,defense programs and targeted response strageties according to the requirements of social development.Based on the above,this dissertation introduces the concept and method of event evolutionary graph.On the basis of systematically combing the existing theories and methods of event evolutionary graph,it divides the types of public emergencies from the domain content dimension and event theme dimension,and formally expresses the public emergencies in the form of six tuples.Futhermore,it constructs the event evolutionary graph for public emergencies from the two important links of event extraction and event fusion.Besides,it selects typical scenarios in the field of public emergencies,namely faceted retrieval and Intelligent Question Answering for application demonstration research.Finally,typhoon events in natural disaster events are illustrated as the specific application background to carry out empirical research of event evolutionary graph.Meanwhile,faceted retrieval system and intelligent question answering system of typhoon events based on event evolutionary graph are developed to verify the rationality,scientificity and usability of the event evolutionary graph.This dissertation consists of seven chapters.Chapter 1 is an introduction.Based on a comprehensive review of foreign research from the perspectives of event evolutionary graph and its application in public emergencies,it summarizes the existing problems in the management of public emergencies and the construction and application of event theory,then puts forward a technical scheme for the construction of event evolutionary graph in the field of public emergencies.Chapter 2 is the basis of theory and method.The theoretical and technical basis of this study mainly includes the theoretical basis of public emergency,the overview of event evolutionary graph,knowledge extraction,knowledge extraction theory and technology,and knowledge fusion theory and technology.Chapter 3 is the method of event extraction in the field of public emergency.Aiming at the domain particularity of public emergencies,this study constructs an event recognition method,including the classification and representation of public emergencies,the definition of event extraction task oriented to the field of emergencies,the extraction method of Public Emergencies Based on Bert and Bi LSTM CRF,and the extraction method of public emergencies relationship based on pattern matching and fault tree.Chapter 4 is the event fusion method in the field of public emergencies.It is an important part of the construction of event evolutionary graph to focus on the implementation of event extraction,eliminating the error,conflict and redundancy of multi-source information,so as to achieve event fusion.This chapter includes the analysis of the cause of event fusion,the solution of data standardization of public emergencies,the multidimensional measurement method of event similarity,and the event fusion scheme for public emergencies.Chapter 5 is about the application of the event evolutionary graph in public emergencies.Having constructed the event evolutionary graph of public emergencies,it is necessary to apply it in specific circumstances.This chapter contains the application scene analysis,faceted retrieval and Knowledge Q&A based on the event evolutionary graph of public emergencies.Chapter 6 is the empirical research and application of the construction of public emergency theory map.Taking examples of the typhoon event in natural disaster events,this study constructs the event evolutionary graph,and applies it to faceted retrieval and Knowledge Q&A in combination with the application scenarios in Chapter 5,to show its scientificity and rationality.This chapter mainly involves:the situation analysis of the construction and application of typhoon event theory atlas,the construction of typhoon event theory atlas,the implementation of typhoon event faceted retrieval system based on theory atlas,and the implementation of typhoon event Intelligent Question Answering System based on theory atlas.Chapter 7 is the summary and prospect.It summarizes the research work of the full text,sorts out the problems existing in the paper writing,and further puts forward the prospective research plan.This dissertation focuses on the whole process of the construction of the event evolutionary graph in the field of public emergencies,including both the event extraction stage and the event fusion stage.The event evolutionary graph of public emergencies in a specific field is displayed with the visualization effect of events and their relationships.Based on the constructed event evolutionary graph,research is demonstrated in faceted retrieval and intelligent Q&A,which are typical aplication scenarios.The aim of this research is to promote the intelligent transition of information management and the modernization of national prevention and control management.