An urban model using complex constrained cellular automata: long-term urban form prediction for Beijing

2011 ◽  
Vol 3 (1/2) ◽  
pp. 159 ◽  
Author(s):  
Ying Long ◽  
Zhenjiang Shen
2013 ◽  
Vol 43 (2) ◽  
pp. 282-295 ◽  
Author(s):  
Michel De Lara ◽  
André de Palma ◽  
Moez Kilani ◽  
Serge Piperno

2008 ◽  
Vol 12 (2) ◽  
pp. 691-702 ◽  
Author(s):  
T. Nehls ◽  
G. Jozefaciuk ◽  
Z. Sokolowska ◽  
M. Hajnos ◽  
G. Wessolek

Abstract. Depositions of all kinds of urban dirt and dust including anthropogenic organic substances like soot change the filter properties of the seam filling material of pervious pavements and lead to the formation of a new soil substrate called seam material. In this study, the impact of the particular urban form of organic matter (OM) on the seam materials CECpot, the specific surface area (As), the surface charge density (SCD), the adsorption energies (Ea) and the adsorption of Cd and Pb were assessed. The Cd and Pb displacement through the pavement system has been simulated in order to assess the risk of soil and groundwater contamination from infiltration of rainwater in paved urban soils. As, Ea and SCD derived from water vapor adsorption isotherms, CECpot, Pb and Cd adsorption isotherms where analyzed from adsorption experiments. The seam material is characterized by a darker munsell-color and a higher Corg (12 to 48g kg-1) compared to the original seam filling. Although, the increased Corg leads to higher As (16m2g-1) and higher CECpot (0.7 to 4.8cmolckg-1), with 78cmolckg-1C its specific CECpot is low compared to OM of non-urban soils. This can be explained by a low SCD of 1.2×10-6molc m-2 and a low fraction of high adsorption energy sites which is likely caused by the non-polar character of the accumulated urban OM in the seam material. The seam material shows stronger sorption of Pb and Cd compared to the original construction sand. The retardation capacity of seam material for Pb is similar, for Cd it is much smaller compared to natural sandy soils with similar Corg concentrations. The simulated long term displacement scenarios for a street in Berlin do not indicate an acute contamination risk for Pb . For Cd the infiltration from puddles can lead to a breakthrough of Cd through the pavement system during only one decade. Although they contain contaminations itself, the accumulated forms of urban OM lead to improved filter properties of the seam material and may retard contaminations more effectively than the originally used construction sand.


1993 ◽  
Vol 25 (8) ◽  
pp. 1175-1199 ◽  
Author(s):  
R White ◽  
G Engelen

Cellular automata belong to a family of discrete, connectionist techniques being used to investigate fundamental principles of dynamics, evolution, and self-organization. In this paper, a cellular automaton is developed to model the spatial structure of urban land use over time. For realistic parameter values, the model produces fractal or bifractal land-use structures for the urbanized area and for each individual land-use type. Data for a set of US cities show that they have very similar fractal dimensions. The cellular approach makes it possible to achieve a high level of spatial detail and realism and to link the results directly to general theories of structural evolution.


2018 ◽  
Vol 61 (4) ◽  
pp. 726-756
Author(s):  
Florian Riedler

AbstractThis article focuses on communal boundaries in nineteenth-century Ottoman Niš, a city located in what is today southern Serbia. In particular, it explores the implications of Robert Hayden’s model of “antagonistic tolerance” for Ottoman urban history. In a first step, by taking into consideration the urban form of Niš from a long-term historical perspective, we consider how urban space was divided between inhabitants with different religious backgrounds. The article then turns to consider the symbolic boundaries that existed between confessional groups in nineteenth-century Niš, which can be traced by looking at the construction of churches and mosques. By examining the ways in which communal boundaries were expressed, negotiated and changed through church and mosque buildings, we can begin to render the confessional policies of the Ottoman authorities more transparent.


2021 ◽  
pp. 662
Author(s):  
Julia Salom Carrasco

Resumen: Con ocasión de la crisis del COVID-19 se han publicado distintos análisis y reflexiones sobre el impacto que ésta puede tener sobre sobre la forma y la dinámica territorial a medio y largo plazo, así como sobre las posibilidades de desarrollo de los distintos territorios. Muchos de ellos subrayan la oportunidad que la crisis puede representar para reconsiderar drásticamente, desde cero, el paradigma actual de producción y consumo, así como el modelo territorial predominante. Aunque la duración temporal de la crisis sanitaria es un factor fundamental en la consolidación de estas nuevas tendencias, la situación actual y evolución probable de la pandemia a escala global nos lleva a afirmar que, hasta cierto punto “la vida después del COVID-19” será “la vida con COVID-19” (OCDE, 2020), de ahí la necesidad de reflexionar sobre las consecuencias a largo plazo, y de proponer un nuevo enfoque de desarrollo territorial que tenga en cuenta las diferentes necesidades y los cambios planteados por el nuevo contexto. En las páginas siguientes recogemos algunas de las ideas principales de estas aportaciones, centrando el análisis en algunos de los temas más estrechamente relacionados con el paradigma del desarrollo local: las economías locales, la sostenibilidad ambiental y social, el modelo territorial y la formación del capital social.   Palabras clave: COVID-19, desarrollo local,” Economía Fundamental”, cambio productivo, forma urbana, capital social.   Abstract: With the COVID-19 crisis, various analyses and reflections have been published on the impact it may have on the shape and dynamics of the territory in the medium and long term, as well as on the development possibilities of the different territories. Many of them underline the opportunity that the crisis may represent to drastically reconsider, from scratch, the current paradigm of production and consumption, as well as the predominant territorial model. Although the temporal duration of the health crisis is a fundamental factor in the consolidation of these new trends, the current situation and probable evolution of the pandemic on a global scale leads us to affirm that, to a certain extent, "life after COVID-19" will be "life with COVID-19" (OECD, 2020), hence the need to reflect on the long-term consequences, and to propose a new territorial development approach that takes into account the different needs and changes posed by the new context. In the following pages we gather some of the main ideas of these contributions, focusing the analysis on some of the issues most closely related to the local development paradigm: local economies, environmental and social sustainability, the territorial model and the formation of social capital.   Keywords: COVID-19, local development, “Basic Economy”, productive change, urban form, social capital.


10.1068/b1288 ◽  
2002 ◽  
Vol 29 (3) ◽  
pp. 431-450 ◽  
Author(s):  
Anthony Gar-On Yeh ◽  
Xia Li

Most cellular automata (CA) urban models assume densities to be uniform for all cells. This is not true in real cities because densities vary substantially from city to city and from urban center to periphery areas. Development density, which affects urban form, is an important factor in urban planning. The authors present a CA model that incorporates density gradient in the simulation of urban development for different urban forms. Development density is obtained from density-decay functions and assigned to the cells when they are converted into developed cells according to CA transition rules. The model, which is based on the concept of ‘grey cells’, can be used as a planning model to explore various combinations of urban forms and development densities. The authors also evaluate and compare the development patterns generated by different density gradients. It is found that development scenarios with high-density development can significantly reduce encroachment on agricultural land and other important environmentally sensitive areas.


2017 ◽  
Vol 2 (1) ◽  
pp. 88-99 ◽  
Author(s):  
Paola Viganò ◽  
Christian Arnsperger ◽  
Elena Cogato Lanza ◽  
Martina Barcelloni Corte ◽  
Chiara Cavalieri

In light of the rapid population growth forecast for the coming years and the powerful transformations already occurring throughout its whole territory, today’s Switzerland stands in urgent need of critical reflection on its urban future. A novel set of concepts and actions is needed in order to produce new visions and operational tools capable of critically reconsidering mainstream debates about Switzerland’s future urban growth. On the one hand, national policies and narratives tend de facto towards lending increasing support to a dynamic of “metropolization,” which usually leads to stronger territorial hierarchization strategies and processes aiming at a spatial condensation of urban services and functions in specific, selected locations. On the other hand, however, the Swiss territory—with its deep rootedness in federalism and its unique aggregative structure—still embodies key features of what, at different times, has been named a single “Grande Ville,” a “dezentralisierte Großstadt,” a “Ville-Territoire” or, more recently, “Stadtland Schweiz.” The country as a whole is still characterized by extended and layered conditions of inhabitability, where the dispersion of the urban fabric, enmeshed within the agricultural and forested landscape, is articulated through horizontal rather that vertical relationships. This paper offers a novel reflection on how the ongoing metropolization process could be seen as a positive force if a markedly different idea of metropolitan space is introduced—the “Horizontal Metropolis.” Its key idea is to distribute and enlarge the benefits which metropolization, if conducted in line with the tradition of decentralization and horizontality, could bring to the Swiss territory and its population. The “Horizontal Metropolis” concept recovers and leverages the various forms of inhabitability and their relation with the infrastructural support. It considers the long-term construction of the Swiss “City-Territory” as a renewable resource, which means reflecting on new life cycles, capitalizing on the urban and territorial embodied energy, and therefore rethinking, without denying it, Switzerland’s extensive and diffused fixed capital. This could be a precious resource to accommodate future urban growth and reorient the form it takes, keeping at bay indiscriminate sprawl as well as its currently predominant ideological counterpart, indiscriminate densification and polarization.


2018 ◽  
Vol 4 (1) ◽  
Author(s):  
Nicolai Lang ◽  
Hans Peter Büchler

Active quantum error correction on topological codes is one of the most promising routes to long-term qubit storage. In view of future applications, the scalability of the used decoding algorithms in physical implementations is crucial. In this work, we focus on the one-dimensional Majorana chain and construct a strictly local decoder based on a self-dual cellular automaton. We study numerically and analytically its performance and exploit these results to contrive a scalable decoder with exponentially growing decoherence times in the presence of noise. Our results pave the way for scalable and modular designs of actively corrected one-dimensional topological quantum memories.


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