240 research outputs found
New accessibility measures based on unconventional big data sources
In health econometric studies we are often interested in quantifying aspects
related to the accessibility to medical infrastructures. The increasing
availability of data automatically collected through unconventional sources
(such as webscraping, crowdsourcing or internet of things) recently opened
previously unconceivable opportunities to researchers interested in measuring
accessibility and to use it as a tool for real-time monitoring, surveillance
and health policies definition. This paper contributes to this strand of
literature proposing new accessibility measures that can be continuously feeded
by automatic data collection. We present new measures of accessibility and we
illustrate their use to study the territorial impact of supply-side shocks of
health facilities. We also illustrate the potential of our proposal with a case
study based on a huge set of data (related to the Emergency Departments in
Milan, Italy) that have been webscraped for the purpose of this paper every 5
minutes since November 2021 to March 2022, amounting to approximately 5 million
observations
Optimal two-stage spatial sampling design for estimating critical parameters of SARS-CoV-2 epidemic: Efficiency versus feasibility
The COVID-19 pandemic presents an unprecedented clinical and healthcare challenge for the many medical researchers who are attempting to prevent its worldwide
spread. It also presents a challenge for statisticians involved in designing appropriate
sampling plans to estimate the crucial parameters of the pandemic. These plans are
necessary for monitoring and surveillance of the phenomenon and evaluating health
policies. In this respect, we can use spatial information and aggregate data regarding
the number of verifed infections (either hospitalized or in compulsory quarantine)
to improve the standard two-stage sampling design broadly adopted for studying
human populations. We present an optimal spatial sampling design based on spatially balanced sampling techniques. We prove its relative performance analytically
in comparison to other competing sampling plans, and we also study its properties
through a series of Monte Carlo experiments. Considering the optimal theoretical
properties of the proposed sampling plan and its feasibility, we discuss suboptimal
designs that approximate well optimality and are more readily applicable
A spatial analysis of employment multipliers in the US
The actual effectiveness of employment promotion policies depends on the ability of the intervention at creating new jobs in the targeted sector, but also, to a large extent, on the impact they have on other parts of the local economy. Estimating the latter effect is therefore quite important for regional economic development policies. Along the lines of Moretti (Am Econ Rev Pap Proc 100: 373-377, 2010), we present an empirical analysis of local employment multipliers using data on 123 US Metropolitan Statistical Areas over the period 1980-2010. From the methodological point of view, in this work not only endogeneity (via instrumental variables estimates), but also spatial spillovers are taken into account. According to the results, the magnitude of the multiplier could be rather limited. On the other hand, there is clear indication that the impact of these interventions is not fully contained within the local economy and they have a positive effect on closely surrounding ones
The SAVEMEDCOASTS-2 webGIS: The Online Platform for Relative Sea Level Rise and Storm Surge Scenarios up to 2100 for the Mediterranean Coasts
Here we show the SAVEMEDCOASTS-2 web-based geographic information system (webGIS) that supports land planners and decision makers in considering the ongoing impacts of Relative Sea Level Rise (RSLR) when formulating and prioritizing climate-resilient adaptive pathways for the Mediterranean coasts. The webGIS was developed within the framework of the SAVEMEDCOASTS and SAVEMEDCOASTS-2 projects, funded by the European Union, which respond to the need to protect people and assets from natural disasters along the Mediterranean coasts that are vulnerable to the combined effects of Sea Level Rise (SLR) and Vertical Land Movements (VLM). The geospatial data include available or new high-resolution Digital Terrain Models (DTM), bathymetric data, rates of VLM, and multi-temporal coastal flooding scenarios for 2030, 2050, and 2100 with respect to 2021, as a consequence of RSLR. The scenarios are derived from the 5th Assessment Report (AR5) provided by the Intergovernmental Panel on Climate Change (IPCC) and encompass different Representative Concentration Pathways (RCP2.6 and RCP8.5) for climate projections. The webGIS reports RSLR scenarios that incorporate the temporary contribution of both the highest astronomical tides (HAT) and storm surges (SS), which intensify risks to the coastal infrastructure, local community, and environment
Soft Image Segmentation: On the Clustering of Irregular, Weighted, Multivariate Marked Networks
The contribution exposes and illustrates a general, flexible formalism, together with an associated iterative procedure, aimed at determining soft memberships of marked nodes in a weighted network. Gathering together spatial entities which are both spatially close and similar regarding their features is an issue relevant in image segmentation, spatial clustering, and data analysis in general. Unoriented weighted networks are specified by an ``exchange matrix", determining the probability to select a pair of neighbors. We present a family of membership-dependent free energies, whose local minimization specifies soft clusterings. The free energy additively combines a mutual information, as well as various energy terms, concave or convex in the memberships: within-group inertia, generalized cuts (extending weighted Ncut and modularity), and membership discontinuities (generalizing Dirichlet forms). The framework is closely related to discrete Markov models, random walks, label propagation and spatial autocorrelation (Moran's I), and can express the Mumford-Shah approach. Four small datasets illustrate the theory
Location patterns of urban industry in Shanghai and implications for sustainability
Chinaâs economy has undergone rapid transition and industrial restructuring. The term âurban industryâ describes a particular type of industry within Chinese cities experiencing restructuring. Given the high percentage of industrial firms that have either closed or relocated from city centres to the urban fringe and beyond, emergent global cities such as Shanghai, are implementing strategies for local economic and urban development, which involve urban industrial upgrading numerous firms in the city centre and urban fringe. This study aims to analyze the location patterns of seven urban industrial sectors within the Shanghai urban region using 2008 micro-geography data. To avoid Modifiable Areal Unit Problem (MAUP) issue, four distance-based measures including nearest neighbourhood analysis, Kernel density estimation, K-function and co-location quotient have been extensively applied to analyze and compare the concentration and co-location between the seven sectors. The results reveal disparate patterns varying with distance and interesting co-location as well. The results are as follows: the city centre and the urban fringe have the highest intensity of urban industrial firms, but the zones with 20â30 km from the city centre is a watershed for most categories; the degree of concentration varies with distance, weaker at shorter distance, increasing up to the maximum distance of 30 km and then decreasing until 50 km; for all urban industries, there are three types of patterns, mixture of clustered, random and dispersed distribution at a varied range of distances. Consequently, this paper argues that the location pattern of urban industry reflects the stage-specific industrial restructuring and spatial transformation, conditioned by sustainability objectives
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