Search results for "Fractal"

Simulating and assessing prospective scenarios

2008

The first part of the paper is centered on the phenomena of urban growth, in order to set the rules for a sustainable scenario of urban development. Then we enter the core of the paper that is the comparison of models. For each of the three compared models, we describe its main theoretical characteristics, the chosen parameters, and the obtained results. In section 6, heterogeneity of the produced results is discussed, and we highlight the points of interest and the lacks of the three models. Here we show that results we obtained feed debates about urban growth management. Finally, concluding remarks at the end of the paper address the general topic of the evaluation of the quality of simul…

Fractal dynamics in chaotic quantum transport

2013

Despite several experiments on chaotic quantum transport in two-dimensional systems such as semiconductor quantum dots, corresponding quantum simulations within a real-space model have been out of reach so far. Here we carry out quantum transport calculations in real space and real time for a two-dimensional stadium cavity that shows chaotic dynamics. By applying a large set of magnetic fields we obtain a complete picture of magnetoconductance that indicates fractal scaling. In the calculations of the fractality we use detrended fluctuation analysis -- a widely used method in time series analysis -- and show its usefulness in the interpretation of the conductance curves. Comparison with a s…

An urban multi-­scale modeling using fuzzy evaluation of accessibility and morphological constraints

2008

International audience; Increasing mobility has contributed since a couple of years to favor urban sprawl. The negative impacts of urban sprawl are well known, in particular the increase of traffic flows and vulnerability of natural resources. Addressing those questions we propose a spatial decision support system based on a multi-scale approach. On the one hand, fractal geometry is used to determine where new urban developments are possible. Here, the central assumption is the fractal nature of urban growth allowing access to various types of amenities: central amenities (retailing, cultural offer...) and peripheral amenities (open landscape). On the other hand, the accessibility to retail…

Comparing the fractality of European urban districts: do national processes matter?

2007

International audience

Fractal structures and environmental regulations in urban growth

1993

Fractal urban growth

1993

International audience

La fractalité des structures urbaines

1994

Urban patterns show often an irregular morphology. The fact that this phenomenon appears often despite of the intensions of planers and that it is not related to a particular historical situation, incites to suppose the existence of self-organisation process, promoting such an evolution. To get more insight in these aspects of urban growth, it has been investigated, whether there exists appropriated quantitative measures to characterize the irregular structures. The analysis of the build-up area of a certain number of agglomerations of the scale of metropolitan areas has shown, that the urban patterns follow an interior order principle, and that they may be characterized by fractal dimensio…

Fractalité tridiastatique: propositions conceptuelles pour l'aménagement urbain

2015

National audience; Le contexte de cette communication est motivé par l’objectif de la ville durable (se¬lon la définition de l’ICLEI), et tente de contribuer aux solutions conceptuelles qui permettent d’y parvenir. Nous partons du principe que l’étalement urbain est certes identifié comme un processus néfaste a‘ la continuation de l’urbanisation (§ 1.1) , mais posons l’hypothèse qu’il nécessite un chan¬gement de paradigme (penser l’espace ur¬bain en 3D et non plus en 2D) pour être dépassé (§ 1.2).

Exploration trans-échelles d'une ville nouvelle à l'aide de l'analyse multiradiale

2017

National audience; L’analyse spatiale du bâti repose généralement sur des indicateurs de caractéristiques morphologiques absolues des bâtiments (taille, élongation, compacité, orientation) ou relatives (espacements, positions par rapport au voisinage, position par rapport au réseau), dont on calcule ensuite la distribution statistique, ou quelques résumés de cette distribution, comme la moyenne et l’écart-type. Ces mesures sont efficaces pour décrire l’aspect du tissu bâti (Regnault 2002, Sabo et al. 2005), mais souffrent d’une limitation importante : elles sont purement locales, et ne disent rien, ou presque, de l’organisation spatiale du bâti à d’autres échelles qui sont celles des quarti…