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The field of urban analytics and city science has seen significant growth and development in the past 20 years. The rise of data science, both in industry and academia, has put new pressures on urban research, but has also allowed for new analytical possibilities. Because of the rapid growth and change in the field, terminology in urban analytics can be vague and unclear. This paper, an abridged synthesis of a panel discussion among scholars in Urban Data Science held at the 2019 American Association of Geographers Conference in Washington, D.C., outlines one discussion seeking a better sense of the conceptual, terminological, social, and ethical challenges faced by researchers in this emergent field. The panel outlines the difficulties of defining what is or is not urban data science, finding that good urban data science must have an expansive role in a successful discipline of “city science.” It suggests that “data science” has value as a “signaling” term in industrial or popular science applications, but which may not necessarily be well-understood within purely academic circles. The panel also discusses the normative value of doing urban data science, linking successful practice back to urban life. Overall, this panel report contributes to the wider discussion around urban analytics and city science and about the role of data science in this domain.

This article investigates the relationship between income and the diversity of sociospatial networks as described by high-density mobile phone application (MPA) Global Positioning System data. Looking at the counties that contain the Atlanta, Boston, Chicago, and Los Angeles metropolitan regions in August and September 2022, this study asks the following questions: How does the racial-ethnic diversity and spatial extent of network of activity space-times—the place and time of daily activities—vary across different income levels? Given the existing literature, are more diverse networks composed of higher income classes? Are there key types of activity space-times that are more likely to be in these networks? Given that the overlap of activity spaces might lead to the formation of stronger social ties, this study aims to provide new evidence of the role of activity spaces in determining the diversity of social exposures with high-resolution spatiotemporal MPA activity. Results suggest that income is an important determinant of diversity in networks, with the highest and lowest income groups both exhibiting the least diversity in networks, whereas institutional spaces like church or school and other surprising places such as the dentist's office are the most likely activity space-times in these networks. [ABSTRACT FROM AUTHOR]

Finding an attractive or best-fit neighborhood for a new resident of any city is not only important from the perspective of the resident him or herself, but has larger implications for developers and city planners. The environment or mood of the right neighborhood is not simply created through traditional characteristics such as income, crime, or zoning regulations - more ephemeral traits related to user-perception also have significant weight. Using datasets and tools previously unassociated with real-estate decision-making and neighborhood planning, such as social media and machine learning, we create a non-deterministic and customized way of discovering and understanding neighborhoods. Our project creates a customizable ranking system for the 195 neighborhoods in New York City that helps users find the one that best matches their preferences. Our team has developed a composite weighted score with urban spatial data and social media data to rank all NYC neighborhoods based on a series of questions asked to the user. The project's contribution is to provide a scientific and calibrated understanding of the impact that socially oriented activities and preferences have towards the uses of space.

This article analyzes the regional variation in outcomes of a seemingly standardized federal neighborhood valuation principle used in home mortgage insurance grading. The objective is to highlight the contingent discriminatory and economic conditions that mediated heterogeneous housing outcomes across different parts of the United States. How did city and regional economic and demographic growth patterns vary before and during the mortgage insurance program implemented through the Federal Housing Administration (FHA)? How might this have shaped loan guarantee patterns? How does preexisting racial housing discrimination relate to outcomes? Adopting an orientation that centers on Whiteness and the benefits of mortgage finance for certain groups and neighborhoods, this analysis uses a Bayesian hierarchical framework to investigate the degree of the FHA's influence between 1940 and 1970, here proxied by the Home Owners' Loan Corporation maps, on A or B ("AB") graded neighborhoods versus C graded neighborhoods in different cities. This article studies how home values and homeownership change over time and whether there are regional variations in the influence of these grades. It also studies what longitudinal socioeconomic patterns might explain the persistence or decline of the AB effect over time. Findings show cities in the West Coast, Southwest, and northern central United States that saw the most housing construction also had the highest proportions of FHA loans to overall dwelling units. There is also a distinctive consistency and persistence of benefit on home value and homeownership to AB graded neighborhoods in these cities, possibly owing to regional shifts in the industrial landscape. [ABSTRACT FROM AUTHOR]

This research uses high-density anonymised mobile phone application (MPA) global-positioning system (GPS) data to describe exposure to racial diversity in different social contexts with an aim to clarify the mechanism linking residential diversity to opportunities for diverse social interactions. In particular, it explores the hypothesis that a diverse residential context does not lead to diverse social contact by comparing three exposure measures – residential, observed and interaction – on the census block group level in Chicago. In doing so, it also explores the contribution of activity spaces to opportunities for diverse social contact. The findings show that the exposure to opportunities for diverse social contact measured by MPA data is generally higher than what is implied by residential census data, especially in areas of high residential segregation in the city. Further, measures using MPA data reveal more spatiotemporal heterogeneity of exposure than that implied by the residential context. [ABSTRACT FROM AUTHOR]

How did institutionalized discriminatory lending policies implemented under the guidance of the Federal Housing Administration (FHA)'s mortgage risk maps impact neighborhood trajectories? Have these spatially restrictive credit designations influenced home value, homeownership, and racial segregation? Using the FHA mortgage risk map of Chicago, Illinois, for new loan guarantees as a case study, I measure outcomes between credit zones and compare these risk regions with the Home Owners' Loan Corporation (HOLC) Residential Security Maps, which represent post hoc measures of mortgage risk and were likely not directly used in loan activities. For areas excluded from FHA loan guarantees, the results suggest a negative impact on home values and homeownership rates and weakly decreased segregation between 1940 and 1980. They also suggest an overcorrection of home values, an undercorrection of homeownership, and an increase in racial segregation in excluded neighborhoods between 1980 and 2010 when these areas may have experienced capital reinvestment. In comparison with the HOLC map, the effects on tracts in Chicago rated worst by the FHA are clearer and suggest a more significant impact during the period of discriminatory mortgage lending. [ABSTRACT FROM AUTHOR]

Aurivillius Bi5Ti3FeO15 (BTFO) multiferroic ceramics with different Cr-doped concentrations have been synthesized by the conventional solid state reaction method. The influences of Cr-doping concentrations on the structural, magnetic, dielectric, and ferroelectric properties of BTFO ceramics are investigated in detail. All these sintered Cr-substituted BTFO ceramics are determined to be layered perovskite Aurivillius structure by X-ray diffraction, as well as the lattice parameters a, b, and c are in good accordance with Vegard's law along with the Cr-doping concentration. The lattice distortion a/b for Aurivillius family decreases with increasing Cr-doping concentration. Moreover, Cr-doping can promote greatly the grain growth of BTFO samples confirmed from field emission scanning electron microscopy characterization. However, no obvious signs of the improvement in ferroelectric properties are found in Cr-doped BTFO ceramics, and abnormal ferroelectric polarization versus electric field (P-E) loops are observed as Cr-doping content is beyond 0.1. Similar [variant_greek_epsilon] (tanδ) versus frequency plots to those of the BTFO sample are exhibited when Cr-doping concentration is less than 0.1. Nevertheless, obvious dielectric dispersion phenomena are shown as the Cr-doping concentration is beyond 0.1, and this dispersion behavior becomes strong with further increasing Cr-doping concentration, which are clearly indicated by the appearance of dielectric loss relaxation peaks in the measurement frequency from 102 Hz to 106 Hz. In addition, the corresponding frequency to relaxation peak shifts towards high frequencies with the Cr-doping concentration. Finally, the same magnetic orderings for all these Cr-doped BTFO ceramics as those of the BTFO one, i.e., superparamagnetic state dominated with antiferromagnetic interaction, are unambiguously found, signifying that the predicted Fe3+-O-Cr3+ 180° ferromagnetic superexchange interaction based on the Goodenough-Kanamori (G-K) rule might not be achieved in BTFO ceramics through Cr substitution by the conventional solid state reaction. [ABSTRACT FROM AUTHOR]

SrTiO3 thin films were epitaxially grown on (100) SrTiO3 substrates using molecular beam epitaxy. The temperature for growth of the films was optimized, which was indicated by x-ray diffraction and further confirmed by microstructural characterization. Photoluminescence spectra show that oxygen-vacancy contributes to red and blue luminescence of oxygen-deficient post-annealed films, and a red shift was observed in blue region. On the other hand, ferromagnetism in film form SrTiO3 was observed from 5 K to 400 K and could be further enhanced with decreasing oxygen plasma partial pressure in annealing processes, which might be explained by the theory involving d0 magnetism related to oxygen-vacancy. From the cooperative investigations of optical and magnetic properties, we conclude that intrinsic defects, especially oxygen-vacancy, can induce and enhance luminescence and magnetism in SrTiO3 films. [ABSTRACT FROM AUTHOR]