Scaling laws and the modern city

Isalgué, A.; Roura, Helena Coch; Serra, Rafael

doi:10.1016/j.physa.2007.04.019

Cited by 35 publications

(32 citation statements)

References 9 publications

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“…The trails in Atta colonies seem analogous to the transport and supply networks of cities [11,29,30]. Resources conveyed along these transport paths determine the economic activity and ultimate productivity (population growth or economic output) of the societies they serve.…”

Section: Discussionmentioning

confidence: 99%

Allometric scaling of foraging rate with trail dimensions in leaf-cutting ants

Bruce

Burd

2012

Proc. R. Soc. B.

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Leaf-cutting ants (Atta spp.) create physical pathways to support the transport of resources on which colony growth and reproduction depend. We determined the scaling relationship between the rate of resource acquisition and the size of the trail system and foraging workforce for 18 colonies of Atta colombica and Atta cephalotes. We examined conventional power-law scaling patterns, but did so in a multivariate analysis that reveals the simultaneous effects of forager number, trail length and trail width. Foraging rate (number of resource-laden ants returning to the nest per unit time) scaled at the 0.93 power of worker numbers, the -1.02 power of total trail length and the 0.65 power of trail width. These scaling exponents indicate that individual performance declines only slightly as more foragers are recruited to the workforce, but that trail length imposes a severe penalty on the foraging rate. A model of mass traffic flow predicts the allometric patterns for workforce and trail length, although the effect of trail width is unexpected and points to the importance of the little-known mechanisms that regulate a colony's investment in trail clearance. These results provide a point of comparison for the role that resource flows may play in allometric scaling patterns in other transport-dependent entities, such as human cities.

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Section: Discussionmentioning

confidence: 99%

Allometric scaling of foraging rate with trail dimensions in leaf-cutting ants

Bruce

Burd

2012

Proc. R. Soc. B.

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“…This may be one of the reasons that allowed the model algorithms to function in different cities regardless of their spatial profile. In fact, these general scaling laws have manifested in many western cities (Bettencourt, 2013;Cottineau et al, 2017;Isalgue et al, 2007;. Interestingly, despite the degree of informality that exists in Middle Eastern cities, it seems that they also tend to follow a similar behaviour of growth.…”

Section: Informality and Scaling Laws: Number Of Intersections Streementioning

confidence: 98%

predictSLUMS: A new model for identifying and predicting informal settlements and slums in cities from street intersections using machine learning

Ibrahim

Titheridge

Cheng

et al. 2019

Computers, Environment and Urban Systems

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Identifying current and future informal regions within cities remains a crucial issue for policymakers and governments in developing countries. The delineation process of identifying such regions in cities requires a lot of resources. While there are various studies that identify informal settlements based on satellite image classification, relying on both supervised or unsupervised machine learning approaches, these models either require multiple input data to function or need further development with regards to precision. In this paper, we introduce a novel method for identifying and predicting informal settlements using only street intersections data, regardless of the variation of urban form, number of floors, materials used for construction or street width. With such minimal input data, we attempt to provide planners and policy-makers with a pragmatic tool that can aid in identifying informal zones in cities. The algorithm of the model is based on spatial statistics and a machine learning approach, using Multinomial Logistic Regression (MNL) and Artificial Neural Networks (ANN). The proposed model relies on defining informal settlements based on two ubiquitous characteristics that these regions tend to be filled in with smaller subdivided lots of housing relative to the formal areas within the local context, and the paucity of services and infrastructure within the boundary of these settlements that require relatively bigger lots. We applied the model in five major cities in Egypt and India that have spatial structures in which informality is present. These cities are Greater Cairo, Alexandria, Hurghada and Minya in Egypt, and Mumbai in India. The predictSLUMS model shows high validity and accuracy for identifying and predicting informality within the same city the model was trained on or in different ones of a similar context.

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“…Firstly, an attempt was made to overcome the multi-sided nature of the concept of density, by giving it objectivity and capacity for morphological description (Rapaport, 1975;Alexander, 1993;Churchman, 1999;Berghauser and Haupt, 2010). Following this, attention was focussed on the different aspects that influence the metabolic efficiency of the built form typologies that make up urban systems and on the definition of the concept of sustainability in the presence of high density (Isalgue et al, 2007, Ratti et al, 2005, Cheng et al, 2006, Zhang et al, 2011, Strømann-Andersen and Sattrup, 2011). …”

Section: Built Form Typologies Solar Radiation and Energy Consumptiomentioning

confidence: 99%

The effects of urban obstructions in Mediterranean climates: built form typology, density and energy

Morganti

Roura²,

Cecere³

2012

ACE: Architecture, City and Environment

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In spite of the ever increasing unsustainable nature of the "conventional" city and its concurrent assertion as a human habitat par excellence, it is important to define intervention strategies that can improve the "metabolic" operation of built environments. If related to urban morphology, these take on more effective potentiality and are a guiding tool for more appropriate, more beneficial interventions. In the specific context of the Mediterranean compact city, the interaction between density, morphology and energy discussed here is one of the components required if not for the complex solution of the problem, then at least for reducing the environmental impact of urban models. The results here proposed of a comparative study carried out on various fabrics in the city of Barcelona, in search of parametric relations between density and energy-environmental behaviour. The said relations, we analyse the effects of urban obstructions: the basis of knowledge required for conscious built environment transformation, towards more efficient conditions.

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Scaling laws and the modern city

Cited by 35 publications

References 9 publications

Allometric scaling of foraging rate with trail dimensions in leaf-cutting ants

Allometric scaling of foraging rate with trail dimensions in leaf-cutting ants

predictSLUMS: A new model for identifying and predicting informal settlements and slums in cities from street intersections using machine learning

The effects of urban obstructions in Mediterranean climates: built form typology, density and energy

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