A persistent homology model of street network connectivity

AbstractWith the aim to enhance sustainability in general including walkability, the recent urban forms of the designs of the Emirati neighborhoods have been denser and more compact, if compared with the older design models. While there are various guidelines and regulations related to the microscale walkability measures for the urban design of neighborhoods in the Emirates but unfortunately the macroscale walkability measures have not received similar attention. So, to investigate how would these denser and more compact recent neighborhoods designs better perform regarding walkability macroscale measures, the research utilized the urban modelling interface (UMI) walkability simulation tool to calculate the UMI Walkscores of these designs because it considers almost all macroscale factors including both urban morphology and urban planning measures and it also allows for the customization of the types, required catchment distances, and weights of the significance of locally provided amenities. The UMI Walkscores were calculated for the six recent denser and more compact neighborhoods designs and were compared with the UMI Walkscore for a conventionally designed model of urban sprawling neighborhoods. Unexpectedly, it has been found out that urban compactness per se is not a sufficient design measure for enhancing walkability in local neighborhood designs, where much higher compactness and density have achieved disappointing UMI Walkscores. So, it seems that for the recent neighborhoods’ designs, little attention was paid to the impact of the street network connectivity measures of Intersection Density, Block Length and the link-to-nodes ratio, on UMI Walkscores, if compared with the main attention paid to increasing FAR through decreasing plot sizes. Meanwhile, the explicit macroscale urban planning measures including the land-use factors of the types, numbers, and the location of amenities, as well as the implicit factors of their destination and global weights seem to be more influential in enhancing the UMI Walkscores but have been less considered when planning these neighborhoods. So, besides considering well-known macroscale urban morphology aspects of street network connectivity and locational distribution of provided amenities, boosting walkability macroscale measures on the design level requires adopting a set of adequately customized measures including the appropriate values of their global and distribution weights. These walkability design weights should be also resilient and continuously reviewed to satisfy the changing needs of the local communities. Based on its findings, the research proposed a five-actions plan to help boost walkability macroscale measures in the design of local urban communities in the UAE.

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The Role of Street Network Connectivity and Access to Everyday Facilities in Shaping Everyday Walking and Cycling in English Cities

Strategies for Sustainable Mobilities ◽

10.4324/9781315610986-8 ◽

2016 ◽

pp. 33-56

Keyword(s):

Network Connectivity ◽

Street Network ◽

Street Network Connectivity

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Disrupted metabolic connectivity in dopaminergic and cholinergic networks at different stages of dementia from 18F-FDG PET brain persistent homology network

Scientific Reports ◽

10.1038/s41598-021-84722-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Tun-Wei Hsu ◽

Jong-Ling Fuh ◽

Da-Wei Wang ◽

Li-Fen Chen ◽

Chia-Jung Chang ◽

...

Keyword(s):

Algebraic Topology ◽

Fdg Pet ◽

Persistent Homology ◽

Network Connectivity ◽

Brain Regions ◽

Imaging Data ◽

Cholinergic Pathways ◽

Positron Emission ◽

Metabolic Connectivity ◽

Neurochemical Changes

AbstractDementia is related to the cellular accumulation of β-amyloid plaques, tau aggregates, or α-synuclein aggregates, or to neurotransmitter deficiencies in the dopaminergic and cholinergic pathways. Cellular and neurochemical changes are both involved in dementia pathology. However, the role of dopaminergic and cholinergic networks in metabolic connectivity at different stages of dementia remains unclear. The altered network organisation of the human brain characteristic of many neuropsychiatric and neurodegenerative disorders can be detected using persistent homology network (PHN) analysis and algebraic topology. We used 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) imaging data to construct dopaminergic and cholinergic metabolism networks, and used PHN analysis to track the evolution of these networks in patients with different stages of dementia. The sums of the network distances revealed significant differences between the network connectivity evident in the Alzheimer’s disease and mild cognitive impairment cohorts. A larger distance between brain regions can indicate poorer efficiency in the integration of information. PHN analysis revealed the structural properties of and changes in the dopaminergic and cholinergic metabolism networks in patients with different stages of dementia at a range of thresholds. This method was thus able to identify dysregulation of dopaminergic and cholinergic networks in the pathology of dementia.

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Children’s Active School Travel: Examining the Combined Perceived and Objective Built-Environment Factors from Space Syntax

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18010286 ◽

2021 ◽

Vol 18 (1) ◽

pp. 286

Author(s):

Ayse Ozbil ◽

Demet Yesiltepe ◽

Gorsev Argin ◽

Greg Rybarczyk

Keyword(s):

Urban Areas ◽

Space Syntax ◽

Network Connectivity ◽

Active Commuting ◽

Street Network ◽

School Travel ◽

Cross Sectional ◽

Active Commuting To School ◽

Active School Travel ◽

Using Data

Increasing active school travel (AST) among children may provide the required level of daily physical activity and reduce the prevalence of obesity. Despite efforts to promote this mode, recent evidence shows that AST rates continue to decrease in suburban and urban areas alike. The aim of this research study, therefore, is to facilitate our understanding of how objective and perceived factors near the home influence children’s AST in an understudied city, İstanbul, Turkey. Using data from a cross-sectional sample of students aged 12–14 from 20 elementary schools (n = 1802) and consenting parents (n = 843), we applied a nominal logistic regression model to highlight important predictors of AST. The findings showed that street network connectivity (as measured by two novel space syntax measures, metric reach and directional reach) was the main deciding factor for active commuting to school, while parents’ perceptions of condition of sidewalks and shade-casting street trees were moderately significant factors associated with AST. Overall, this study demonstrated the significance of spatial structure of street network around the homes in the potential for encouraging AST, and more importantly, the need to consider objective and perceived environmental attributes when strategizing means to increase this mode choice and reduce ill-health among children.

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TESTING THE EFFECTIVENESS OF THE STREET NETWORK OF CITIES (ON THE EXAMPLE OF PETROZAVODSK)

The economy of the North-West: problems and prospects of development ◽

10.52897/2411-4588-2021-2-145-150 ◽

2021 ◽

Vol 2 (65) ◽

pp. 145-150

Author(s):

Evgeny P. Dudkin ◽

◽

Abujwaid Husam Abbas Mohsin ◽

Leonid A. Losin ◽

◽

...

Keyword(s):

Graph Theory ◽

Public Transport ◽

Traffic Congestion ◽

Road Network ◽

Network Connectivity ◽

Transport Network ◽

Transport Infrastructure ◽

Street Network ◽

Real Network ◽

The City

The transport network of cities can be represented as a complex of streets and passages, as well as elements of public transport infrastructure unconnected with the street and road network. It is reasonable to represent the real network in the form of a simplified network based on graph theory to analyze the properties of the transport network. There are various methods of network connectivity assessment, including those based on various indices. According to all indicators in the street and road network of the city of Petrozavodsk it is necessary to increase the number of units. The implementation of recommendations for changes of the street and road network of the city of Petrozavodsk will reduce traffic congestion, the number of accidents and transport expenses. It is recommended to use the proposed method to assess and improve the street and road network of cities.

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