The values of urban design - spatial models

Urban network morphometrics (UNeMos) is a research technique and a design decision aid in urban design. UNeMOS are network science-based configurational metrics of urban morphology that can inform urban designing decision-making, helping designers to discriminate between different 2D and 3D design options. However, some UNeMOS differ from the standard link/node network encoding by using a transport network’s specific encoding, thus lacking usability in mainstream transport and transport geography and analytical power in 3D. There is also a lack of comparison between these encodings and whether the transport geography combination of standard encoding/closeness centrality analysis using Euclidean, angular, or combination thereof are as discriminant or more of urban design network layout in 2D and 3D. The commentary addresses this research gap by reflecting on how the research original contributions reported in the collected publications have deployed diverse combinations of transport network encoding and spatial models of distance to evaluate the values of transport network configuration. The commentary critically contextualises the publications’ original contributions with reference to a leading research question and a sub-question: How well does UNeMOS, as a standard link/node spatial model and nonstandard spatial model, discriminate urban network configurations in 2D or 3D to capture urban design values? The publications cover urban morphology, form, property pricing, transport planning, spatial distribution, high-density city areas, urban design, and network analysis. The publications demonstrate a deep understanding of various aspects of intra-urban and urban studies, including historical morphological roots, challenges for future research, and their practical applications in urban design and planning. The methods employed in these studies involve a variety of quantitative and qualitative approaches. These include, among others, hedonic pricing modelling, multivariate models, road and metro network encoding, 2D and 3D spatial Design Network Analysis (sDNA) software, pedestrian standard path centre line network encoding, and value-based urban design. These methods have investigated the association between urban morphology, property prices, transport access, land-use resources, and pedestrian flows in contrasted urban contexts. The approaches in the publications demonstrate a comprehensive understanding of the complexities and interdependencies in intra-urban and urban studies. The research explores various spatial scales, from local urban design to macro-meso transport planning, and investigates the relationship between outdoor and indoor 3D pedestrian networks in high-density urban areas. Overall, the breadth and depth of the research in these publications and their original contributions showcase a strong foundation in intra-urban and urban studies, highlighting the importance of understanding urban environments’ spatial, socioeconomic, and morphological aspects for effective planning and design. Summary of the publications and contributions: Publication 1: Chiaradia, A., 2019. Urban Morphology/Urban Form. In: A. Orum, ed. The Wiley Blackwell Encyclopedia of Urban and Regional Studies. Hoboken, NJ: WileyBlackwell, pp. 1-6. The paper contextualises and traces succinctly, from 1830 to 2019, the historical roots of urban morphology, including street network focus. The article provides a general introduction to critical concepts. Space syntax is contextualised as performative urban morphology and referenced to the early work of Stübben (1911). The main contribution is the identification of three key challenges for future research: epistemological embedding, qualitative ontology, and a unified approach that bridges descriptive/explanatory and prescriptive/normative aspects. Publication 2: Chiaradia, A.*, Hillier, B., Schwander, C. and Barnes, Y., 2013. Compositional and urban form effects on residential property value patterns in Greater London. Proceedings of the Institution of Civil Engineers-Urban Design and Planning, 166(3), pp.176-199. This research used a hedonic pricing modelling framework. The road network encoding uses standard road centre line encoding transformed by space syntax software and centralities metrics quantitative spatial characterisation of road network shape/accessibility to investigate the association with property price of a large sample of adjacent properties (≈100,000). Findings are aligned with extant theory related to the hedonic modelling of the residential property price; dwelling size is the most important. The research reveals the importance of road network shape and accessibility characteristics in determining residential property prices in Greater London. The main contribution is the identification of two spatial scales associated with property prices: a local urban design scale (= 2,000 m). Publication 3: Chiaradia, A.*, Hillier, B., Schwander, C. and Wedderburn, M., 2012. Compositional and urban form effects on centres in Greater London. Proceedings of the Institution of Civil Engineers-Urban Design and Planning, 165(1), pp.21-42. This research used a multi-variate model, using standard road centre line encoding transformed by space syntax software and centralities metrics quantitative spatial characterisation of road network shape/accessibility and socio-economic variables to investigate the association with commercial rental values of a large sample of commercial property located in designated sub-centres. Findings show that a sub-centre can be spatially distinguished from its non-centre surroundings. A sub-centrality spatial signature: sub-centre spatial and socio-economic typology are identified. Of the two main space syntax spatial variables associated with the sub-centres signatures, one would be the remit or urban design (local spatial scale, walking scale <= 800 m) and the other (meso-scale, <= 2,000 m) would be the remit of transport planning. Publication 4: Zhang, L., Chiaradia, A.* & Zhuang, Y. A., 2015. Configurational Accessibility Study of Road and Metro Network in Shanghai. In: Q. Pan & J. Cao, eds. Recent Developments in Chinese Urban Planning. Heidelberg: Springer, pp. 219-245. This research deployed standard road centre line encoding, metro network topological encoding and 2D spatial Design Network Analysis (sDNA) software quantitative spatial characterisation of road network and metro network shape/accessibility to investigate the probability density function of spatial distribution of metro system access points, bus access points and commercial land use in a Mega City. The research shows the uneven spatial distribution of metro access points, bus access points, and commercial land use in Shanghai, with 60-70% associated with the top three deciles of road and metro network shape/accessibility. The main contribution is the comprehensive analysis of the spatial distribution of transport and land-use resources in a mega-city context. Publication 5: Zhang, L. & Chiaradia, A.*, 2019. Three-dimensional Spatial Network Analysis and Its Application in a High Density City Area, Central Hong Kong (In Chinese). Urban Planning International, 33(1), pp. 46-53. This research used 3D pedestrian standard path centre line network encoding and 3D sDNA software quantitative spatial characterisation of outdoor and indoor multi-level pedestrian network shape/accessibility to investigate their association with pedestrian flow level in one of the most complex multi-level-built environments. The research reveals a high association between the standard spatial characterisation of outdoor and indoor multi-level pedestrian network shape/accessibility and pedestrian flow levels in a complex built environment. The main contribution is the demonstration of the interdependence between outdoor and indoor pedestrian networks in a high-density urban context. Publication 6: Chiaradia, A.*, Sieh, L. and Plimmer, F., 2017. Values in urban design: A design studio teaching approach. Design Studies, 49, pp. 66-100. The paper refers to physical configurations in general and the movement network that UNeMos are measuring. It articulates a theoretical bridge between the technicalities of measuring urban morphology and the creative application of resulting insights about the impact of any proposed, designed urban shape on the performance of the urban ‘place’ of which it is a part. The basis of the bridge is the concept of value. This is not simply ‘price’ but an interdisciplinary social scientific compound construct inspired by an extensive anthropological meta-review of value: “that which matters, and the extent to which that matters.” The research establishes a theoretical bridge between urban morphology measurement and urban design creativity through the concept of value, which is adapted from Graeber’s general conceptualisation. The main contribution is developing a value-based approach to urban design, as demonstrated through the analysis of student work in an urban design studio. Publication 7: Chiaradia, A., Cooper, C., Webster, C., 2011, spatial Design Network Analysis Software, & Cooper, C.H. and Chiaradia, A.J., 2020. sDNA: 3D spatial network analysis for GIS, CAD, Command Line & Python. SoftwareX, 12, p.100525. Spatial Design Network Analysis (sDNA) is a toolbox for 2D and 3D spatial network analysis, especially street/path/urban network analysis, motivated by a need to use standard network links/nodes as the principal unit of analysis to analyse existing and projected network data. sDNA is usable from QGIS & ArcGIS geographic information systems, AutoCAD, Rhino Gh, and the command line via its own Python API. It computes measures of accessibility (reach, mean distance/closeness centrality, gravity), flows (bidirectional betweenness centrality) and efficiency (circuity) as well as convex hull properties, localised within lower- and upper-bounded radial bands. Weighting is flexible and can use geometric properties, data attached to links, zones, matrices or combinations of the above. Motivated by a desire to base network analysis on route choice and spatial cognition, distance can be network-Euclidean, angular, a mixture of both, custom, or specific to cyclists (avoiding slope and motorised traffic). In addition to statistics on network links, the following outputs can be computed: geodesics, network buffers, accessibility maps, convex hulls, flow bundles and skim matrices. Further tools assist with network preparation and calibration of network models to observed data. To date, sDNA has been used mainly for urban network analysis by academics and city planners/engineers for tasks including predicting pedestrian, cyclist, vehicle and metro flows and mode choice and quantifying the built environment for epidemiology and urban planning & design. The main contribution is developing a user-friendly and flexible software tool that supports various types of 3D network analysis, including accessibility, flows, efficiency measures, and various output formats and tools. The commentary critically introduces, compares, and analyses various spatial models of distance using the closeness centrality of a network, combinations of transport network encoding and topological, Euclidean, angular and hybrid distances for their capacity and limitations to discriminate transport network layout. It contextualised the issues related to how and what could be “counted so as to reveal the differences between one settlement structure and another?” (Hillier & Hanson, 1984) in 2D or 3D to capture urban design values. The main findings are as follows: • Topologic distance is inferior at measuring and discriminating distinct layout configurations of the transport networks. • To a very good extent, Euclidean distance measures and discriminates distinct layout configurations of transport networks, yet mainly grid-like layout. • Angular distance remedies the issues of Euclidean distance related to a deformed grid yet introduces errors that can be resolved by Hybrid distance. The link/node model of encoding transport network combined with closeness centrality of the network using spatial models of distance seems valid in discriminating distinct layout configurations of 2D and 3D transport networks. The publications’ original contributions demonstrate that these techniques empirically capture 2D and 3D urban design values

Measuring the impact of spatial network layout on community social cohesion: a cross-sectional study

Background There is now a substantial body of research suggesting that social cohesion, a collective characteristic measured by the levels of trust, reciprocity and formation of strong social bonds within communities, is an important factor in determining health. Of particular interest is the extent to which factors in the built environment facilitate, or impede, the development of social bonds. Severance is a characteristic of physical environments which is hypothesized to inhibit cohesion. In the current study we test a number of characteristics of spatial networks which could be hypothesized to relate either to severance, or directly to community cohesion. Particular focus is given to our most promising variable for further analysis (Convex Hull Maximum Radius 600 m). Methods In the current study we analysed social cohesion as measured at Enumeration District level, aggregated from a survey of 10,892 individuals aged 18 to 74 years in the Caerphilly Health and Social Needs Cohort Study, 2001. In a data mining process we test 16 network variables on multiple scales. The variable showing the most promise is validated in a test on an independent data set. We then conduct a multivariate regression also including Townsend deprivation scores and urban/rural status as predictor variables for social cohesion. Results We find convex hull maximum radius at a 600 m scale to have a small but highly significant correlation with social cohesion on both data sets. Deprivation has a stronger effect. Splitting the analysis by tertile of deprivation, we find that the effect of severance as measured by this variable is strongest in the most deprived areas. A range of spatial scales are tested, with the strongest effects being observed at scales that match typical walking distances. Conclusion We conclude that physical connectivity as measured in this paper has a significant effect on social cohesion, and that our measure is unlikely to proxy either deprivation or the urban/rural status of communities. Possible mechanisms for the effect include intrinsic navigability of areas, and the existence of a focal route on which people can meet on foot. Further investigation may lead to much stronger predictive models of social cohesion

Changes in diet and trophic position of a top predator 10 years after a mass mortality of a key prey

After the disappearance of primary prey, seabirds exhibit gradually decreased breeding performance, and eventually the population size drops. Results are presented of an investigation into the diet of little penguins (Eudyptula minor) at Phillip Island, Australia, during a period when their key prey, pilchard (Sardinops sagax), declined dramatically. Data from stomach flushing (1982-2006) were used, supported by stable isotope (δ 15N, δ13C) analyses of blood samples (2003, 2004, and 2006). The effect of the pilchard mortality on penguin diet was immediate, the birds shifting to a diet almost devoid of pilchard, and this was followed by 2 years of low breeding success, with considerably fewer penguins coming ashore. During periods when pilchard was not part of the diet, penguins consumed prey of a higher trophic level, e.g. higher values of δ15N. Variability in penguin blood δ15N coincided with years of low prey diversity. The disappearance of pilchard resulted in a decrease in prey diversity and led penguins to >fish up> the foodweb, possibly because of the simplified trophic structure. After 1998, however, breeding success re-attained average levels and the numbers of penguins coming ashore increased, probably because of increased abundance of prey other than pilchard after a 3-year period of food scarcity. Although little penguins apparently compensated over time, a less-flexible diet could make them ultimately vulnerable to further changes in their foodweb. © 2010 International Council for the Exploration of the Sea.Peer Reviewe

Introducing wearable haptics for rendering velocity feedback in VR serious games for neuro-rehabilitation of children

Rehabilitation in virtual reality offers advantages in terms of flexibility and parametrization of exercises, repeatability, and continuous data recording and analysis of the progress of the patient, also promoting high engagement and cognitive challenges. Still, most of the proposed virtual settings provide a high quality, immersive visual and audio feedback, without involving the sense of touch. In this paper, we show the design, implementation, and first evaluation of a gaming scenario for upper limb rehabilitation of children with cerebral palsy. In particular, we took care to introduce haptic feedback as a useful source of sensory information for the proposed task, considering—at the same time—the strict constraints for haptic wearable devices to comply with patient’s comfort, residual motor abilities, and with the embedded tracking features of the latest VR technologies. To show the potential of haptics in a rehabilitation setup, the proposed device and rendering method have been used to improve the velocity control of upper limb movements during the VR exercise, given its importance as a motor recovery metric. Eight healthy participants were enrolled, and results showed that haptic feedback can lead to lower speed tracking errors and higher movement smoothness, making the proposed setup suitable to be used in a rehabilitation context as a way to promote movement fluidity during exercises

GaAs(111)A and B in hydrazine sulfide solutions : extreme polarity dependence of surface adsorption processes

Chemical bonds formed by hydrazine-sulfide treatment of GaAs(111) were studied by synchrotron photoemission spectroscopy. At the B surface, the top arsenic atoms are replaced by nitrogen atoms, while GaAs(111)A is covered by sulfur, also bonded to underlying gallium, despite the sulfide molar concentration being 103 times smaller than that of the hydrazine. This extreme dependence on surface polarity is explained by competitive adsorption processes of HS- and OH- anions and of hydrazine molecules, on Ga- adsorption sites, which have distinct configurations on the A and B surfaces

A soft, synergy-based robotic glove for grasping assistance

This paper presents a soft, tendon-driven, robotic glove designed to augment grasp capability and provide rehabilitation assistance for postspinal cord injury patients. The basis of the design is an underactuation approach utilizing postural synergies of the hand to support a large variety of grasps with a single actuator. The glove is lightweight, easy to don, and generates sufficient hand closing force to assist with activities of daily living. Device efficiency was examined through a characterization of the power transmission elements, and output force production was observed to be linear in both cylindrical and pinch grasp configurations. We further show that, as a result of the synergy-inspired actuation strategy, the glove only slightly alters the distribution of forces across the fingers, compared to a natural, unassisted grasping pattern. Finally, a preliminary case study was conducted using a participant suffering from an incomplete spinal cord injury (C7). It was found that through the use of the glove, the participant was able to achieve a 50% performance improvement (from four to six blocks) in a standard Box and Block test

Cs-induced charge transfer on (2x4)-GaAs(001) studied by photoemission

Cesium adsorption on 2x4 GaAs (001) was studied by photoemission and low energy electron diffraction. The different Cs induced changes of the As 3d and Ga 3d core level spectra show that charge transfer is almost complete for Ga surface sites, but is negligible to surface As at a coverage smaller than 0.3 ML. The situation is opposite for a coverage larger than 0.3ML, at which transfer occurs to As but no longer to Ga. Charge transfer to As atoms leads to disordering and destabilization and induces surface conversion from the As-rich surface to the Ga-rich 4x2 one after annealing at a reduced temperature of 450 C