Research On The Evolution Of Urban Renewal Policy And Evaluation Of Its Implementation Effect

China is advancing with the rapid de velopment of urbanization and cities have driven large-scale population rapid increase in mobility,which caused the prominent problem of old buildings.Urban renewal is currently widely promoted.In 2009,the "Shenzhen Urban Renewal Measures",which clarified the planning,classification,and specific regulations for urban renewal,is released.Other cities also issued a series of policies to promote and guide the urban renewal projects.Therefore,in order to verify the success of a series of urban renewal policies,this article believes that it is necessary to discuss the effects of urban renewal policies.Initially,through sorting out the urban renewal policy texts,this article strives to clarify the overall urban renewal policy stages in China,and identifies the relevance of high-frequency keywords in the policy in order to clarify the policy issues;Second,the implementation elements of the urban renewal policies and the relationship between them are regarded as a system,and a system dynamics model of the effect of urban renewal policies is established based on the principles of system dynamics :(1)analyze the impact mechanism of urban renewal policies and the influencing factors of urban renewal projects;(2)after analyzing the system goals and boundaries,draw the causal loops and system causality diagrams of the four subsystems of policy,architecture,industry,and environment;(3)clarify the names and definitions of variables in the system,draw an overall system flow diagram,and establish system dynamic equations.In the empirical study,this paper analyzes the current overview of Shenzhen's urban renewal projects,describes the table functions involved in the system,and bri ngs part of the Shenzhen urban renewal project data and assumptions or empirical data to the system of the established urban renewal policy implementation to simulate.Then,the validity of the model has been determined by visual inspect ation,operation inspectation and history inspection in order to test the validity of the model.Then,use the system dynamics software Vensim to conduct the sensitivity analysis on the urban renewal policies,analyze the operation trend after the change of policy factors and project subsidies and compare their differences of with initial value.Finally,on the basis of empirical research and sensitivity analysis,it provides policy recommendations for the government to formulate policies and de velopers to enter urban renewal projects.Empirical research results show that by increasing supportive policy factors,the cost of urban renewal projects can be significantly reduced;by increasing project subsidies,the cost of urban renewal projects can be partially reduced,and the activated land area is significantly increased.Finally,based on the simulation results,it provides relevant suggestions for the government to formulate urban renewal policies,with a view to assisting the development of urban renewal projects.