Study On Spatial Complexity Evolution Mechanism Of Coastal Informal Settlements Based On Fractal Theory

Recently,the development of coastal cities has entered a turning period,and inventory planning has become transformational goal of the spatial development of coastal cities.With the rapid development of the marine economy,coastal informal settlement spaces in coastal zones have become the concentrated embodiment of coastal transformation issues.Therefore,the sustainable development of informal settlements in the coastal zone has always been a hot research topic for developing countries.The joint development of the coastal zone and informal settlements has focused on coastal inventory planning.In recent years,due to the Silk Road Economic Belt,the geographical advantages and human resources advantages of the Maritime Silk Road have attracted many attentions.As a cultural concentration along the Maritime Silk Road,the study of informal settlement space in the coastal areas has also attracted extensive attentions from academic circles.Study on the evolution mechanism of coastal informal settlement space has become a significant issue during the construction of China’s Maritime Silk Road.At the same time,the complexity of informal settlements under the fractal theory has become a vital frontier issue of "planning rationalization." However,existing studies lack the analysis of the spatial complexity evolution of coastal settlements and focus on the description of urban complexity.In particular,the relationship between the complexity of settlement space and human settlements has not been analyzed yet.This paper lays its foundation on fractal theory by giving the research background and scientific study from the perspective of complexity science.The optimization of fractal dimension calculation method is suitable for the coastal spatial characteristics of informal settlements.The rational recognition of informal settlement fractal characteristic analyzes the complex evolution of social and economic influence factors.The internal and external aspects systematically reveal the mechanism of the complex evolution of coastal informal settlement space.It aims to provide technical support and decision-making basis for the spatial renewal of Xiamen’s coastal informal space and a reference for the "planning rationalization" research of other coastal informal settlement spaces in China to promote the sustainable development of informal coastal settlements and to promote the coordinated development of coastal belt and coastal informal settlements.Under the technical route of "optimizing technical means--judging laws and existing problems--exploring dynamic mechanicsm and solutions," the subsequent studies are carried out in this paper:First,optimization technology is investigated.Based on fractal theory and coastal informal settlement space characteristics,the study of image edge detection technology based on sea-land interface,dynamic box cover technology,scale-free area,and the ideal interval of fractal dimension and the critical value are investigated to optimize the traditional fractal dimension analysis method for coastal informal settlements space.Nonlinear analysis models for the time evolution of the complex system of coastal space and the influences of internal and external dynamics are constructed.Secondly,the evolution law,development direction,and existing problems of the fractal characteristics of the complexity of informal settlement space in Xiamen are analyzed.The fractal characteristics of informal settlement spaces in Xiamen are studied from three aspects: time effect,hierarchy effect,and equilibrium.The results show that informal settlements’ spatial boundary dimension evolution inside and outside of Xiamen Island is allometric convergence.The spatial texture presents a diversified growth trend.In the whole period,the correlation between different levels is weak,and the development of different regions is unbalanced.The study reveals that the spatial boundary formed by the informal settlements in the island has reached a highly ordered state,and completely lost complexity.Some informal settlements in the island have lost the complex characteristics of traditional coastal informal settlements.However,the informal coastal settlement space outside the island may reach the critical value of fractal characteristics at the end of the 14 th Five-Year Plan.Therefore,the coordinated development of the coastal zone and informal settlements of Xiamen is highly urgent.Finally,the influencing factors and mechanism are investigated.The evolution mechanism of coastal informal settlement space in Xiamen is expounded from internal and external aspects to guide the coordinated development of the coastal zone and informal settlement space from the perspective of land-sea coordination.On the one hand,the external driving force of the complexity evolution of coastal informal settlement space is revealed from coastline constraint force,industrial economic engine force,and population structure driving force.An analysis model is established to analyze the impacts of coastal boundary dimension,population structure,and industrial economy on the fractal evolution of informal coastal settlements in Xiamen.Based on the coastal boundary dimension of informal coastal settlement space,the threshold interval of an industrial economy and population structure is proposed.On the other hand,for coastal informal settlements space,nonlinear relationship between the internal economic structure,population structure,land use structure and the fractal dimension show that the informal coastal settlements update the path of the space.The dimension threshold value updates strategy and improves the understanding of the self-adjusting mechanism of elastic coastal informal settlements.This study,at the technical level,lays its basis upon the fractal theory,from the sea-land interface detection technique of image extraction,dynamic box cover technology,scale-free area expansion,and the ideal interval and the critical value of fractal dimension and so on.The fractal dimension calculation method is optimized to provide the valuable coastal informal settlements morphological markers and dynamic mechanism analysis tools.It provides innovative technical means for the spatial complexity analysis of informal coastal settlements under "planning rationalization." At the theoretical level,under the perspective of coastal informal settlements space,fractal dimension calculation and its time evolution establish the fractal characteristics of Xiamen coastal informal settlements space,quantitatively reveal the complexity of the coastal informal settlements,and predict the spatial development trends.It provides a theoretical basis for the quantitative analysis of the coordinated development of space and people in coastal zones and informal settlements.Furthermore,the selection of Xiamen city as a demonstration embarks from the social-space in informal settlements.It reveals the internal and external influencing factors and dynamic mechanism the coastal informal settlements,and establishs fractal dimension as a key parameter of social and economic indicators.This study not only provides a scientific basis for formulating the fine renewal strategy of settlement space,but also provides a reference for the study of "planning rationalization" of coastal informal settlement space in China.