| The Urban Growth Boundary is an important policy tool to control urban land expansion and curb disorderly urban sprawl.As cities continue to expand and develop,their complexity also increases.This study aims to establish a model for the expansion mechanism of UGB based on inventory control,which can guide UGB control in complex external environments and provide a new perspective for the dynamic regulation of UGB.Firstly,this paper elaborates on the principles and related framework of the urban growth boundary(UGB)extension model based on cellular automata and inventory control.Two-dimensional event-driven and time-driven urban growth boundary extension mechanism model are constructed,and the parameter design of various cost related to inventory,including holding costs,ordering costs,and shortage costs.ordering costs,and shortage costs.By comparing the different types of costs and considering the control objectives of the model,this study aims to provide a useful reference for the practical application of the UGB expansion mechanism.The probability distribution function is an essential and important tool in inventory control models.In order to address the uncertainty problem of external land demand in the urban growth boundary expansion mechanism model,this study introduces a probability distribution model.The aim is to explore the optimal probability distribution of land demand in various municipal administrative districts in China over the years.This provides a reference and basis for the selection of model parameters in the next chapter.Based on the hypothetical parameters set by the model,this study analyzes the impact of the probability distribution model,order quantity,safety stock level,and other parameters of urban random land demand on various types of costs in the urban growth boundary expansion mechanism model.The study concludes that(1)the normal distribution,lognormal distribution,and Pareto distribution are better suited to describe the probability distribution of land demand in various cities in China.The event-driven scaling mechanism has more stability advantages when managing random demand that obeys the Pareto distribution assumption,while the time-driven scaling method has more stability advantages when managing random demand that follows the normal distribution and the lognormal distribution assumptions.(2)When the subscription volume increases,the total cost of land deficiency decreases for both types of expansion mechanisms,while the holding and subscription costs increase,with the total cost showing a trend of first decreasing and then increasing,and the minimum value of the total cost always appears at the inflection point where the deficiency costs level off.When the subscription volume of the land reserve is large enough,the event-driven expansion mechanism has more advantages of management and flexibility.(3)An increase in the safety stock level will cause the total inventory cost to rise.It is advisable to formulate a reasonable level of safety stock to avoid the risk of land supply.In the time-driven expansion mechanism,the 3-5 years subscription time point can better control the cost changes and maximize the time-driven advantage. |
