Design And Implementation Of Dispatch And Distribution System Of Municipal Emergency Broadcasting

The frequent occurrence of natural disasters and emergencies not only brings enormous economic losses,but also threatens the safety of people's lives and property.Establishing an emergency broadcasting system with wide coverage,fast response speed,flexible dispatch and safety and reliability has become an important technical means for government departments to deal with natural disasters and emergencies.Dispatch and distribution system is an important part of emergency broadcasting system.It shoulders the responsibility of unified dispatch and command of emergency broadcasting resources.At present,only real-time voice function and single broadcasting form can not meet the actual requirements.Aiming at the functional requirements of the municipal emergency broadcasting system,this thesis designs and implements a dispatch and distribution system which can provide multiple broadcasting modes.The main work of this paper is as follows:(1)This thesis analyses the background and significance of emergency broadcasting,and studies the construction experience of emergency broadcasting in developed countries,so as to provide reference for the construction of emergency broadcasting in China.The key technologies of dispatch and distribution system are analyzed,including AJAX technology for asynchronous communication between browser and server,JSON protocol for data transmission,DFA(Deterministic Finite Automaton)algorithm for filtering sensitive words,etc.(2)According to the requirement analysis and design principle of the dispatch and distribution system,each functional module is designed and implemented in detail.The functions of timing task,real-time task,text broadcasting and sensitive word filtering are realized respectively.(3)Aiming at the problem of low efficiency of dispatching and distributing in server,multithreading is adopted to improve the efficiency of dispatching and distributing to a great extent.To solve the problem of low performance of sensitive words filtering,DFA algorithm is used to optimize and Map set is used to store sensitive words,which greatly improves the efficiency of sensitive words filtering.When the number of text words reaches 5000 words,the filtering efficiency of sensitive words is increased by more than two times.(4)It has been proved that each function module runs steadily,CPU occupancy rate and concurrent access basically meet the design requirements,and can meet the needs of dispatching and distribution of emergency broadcasting system at the municipal level.