19 research outputs found
Geo-located Twitter as the proxy for global mobility patterns
In the advent of a pervasive presence of location sharing services
researchers gained an unprecedented access to the direct records of human
activity in space and time. This paper analyses geo-located Twitter messages in
order to uncover global patterns of human mobility. Based on a dataset of
almost a billion tweets recorded in 2012 we estimate volumes of international
travelers in respect to their country of residence. We examine mobility
profiles of different nations looking at the characteristics such as mobility
rate, radius of gyration, diversity of destinations and a balance of the
inflows and outflows. The temporal patterns disclose the universal seasons of
increased international mobility and the peculiar national nature of overseen
travels. Our analysis of the community structure of the Twitter mobility
network, obtained with the iterative network partitioning, reveals spatially
cohesive regions that follow the regional division of the world. Finally, we
validate our result with the global tourism statistics and mobility models
provided by other authors, and argue that Twitter is a viable source to
understand and quantify global mobility patterns.Comment: 17 pages, 13 figure
Geotagging One Hundred Million Twitter Accounts with Total Variation Minimization
Geographically annotated social media is extremely valuable for modern
information retrieval. However, when researchers can only access
publicly-visible data, one quickly finds that social media users rarely publish
location information. In this work, we provide a method which can geolocate the
overwhelming majority of active Twitter users, independent of their location
sharing preferences, using only publicly-visible Twitter data.
Our method infers an unknown user's location by examining their friend's
locations. We frame the geotagging problem as an optimization over a social
network with a total variation-based objective and provide a scalable and
distributed algorithm for its solution. Furthermore, we show how a robust
estimate of the geographic dispersion of each user's ego network can be used as
a per-user accuracy measure which is effective at removing outlying errors.
Leave-many-out evaluation shows that our method is able to infer location for
101,846,236 Twitter users at a median error of 6.38 km, allowing us to geotag
over 80\% of public tweets.Comment: 9 pages, 8 figures, accepted to IEEE BigData 2014, Compton, Ryan,
David Jurgens, and David Allen. "Geotagging one hundred million twitter
accounts with total variation minimization." Big Data (Big Data), 2014 IEEE
International Conference on. IEEE, 201
Nuevas fuentes de información geográfica en turismo: las oportunidades de sightsmap.com
La producción de información geográfica ha cobrado un ritmo antes insospechado, gracias a instituciones y empresas, pero especialmente a las acciones voluntarias (Web 2.0). Uno de los campos en los que se abren mayores posibilidades para el uso de la nueva información geolocalizada es el turismo, ya que sus actividades son fácilmente monitorizables. Una de las fuentes más conocidas, Panoramio exhibe fotografÃas de lugares tomadas y georreferenciadas por usuarios. Esta comunicación presenta las oportunidades que tienen, para el análisis del turismo, la información de Panoramio y la explotación que hace de ella la herramienta Sightsmaps, a diferentes escalas
Large-Scale Mapping of Human Activity using Geo-Tagged Videos
This paper is the first work to perform spatio-temporal mapping of human
activity using the visual content of geo-tagged videos. We utilize a recent
deep-learning based video analysis framework, termed hidden two-stream
networks, to recognize a range of activities in YouTube videos. This framework
is efficient and can run in real time or faster which is important for
recognizing events as they occur in streaming video or for reducing latency in
analyzing already captured video. This is, in turn, important for using video
in smart-city applications. We perform a series of experiments to show our
approach is able to accurately map activities both spatially and temporally. We
also demonstrate the advantages of using the visual content over the
tags/titles.Comment: Accepted at ACM SIGSPATIAL 201
Mining Urban Performance: Scale-Independent Classification of Cities Based on Individual Economic Transactions
Intensive development of urban systems creates a number of challenges for
urban planners and policy makers in order to maintain sustainable growth.
Running efficient urban policies requires meaningful urban metrics, which could
quantify important urban characteristics including various aspects of an actual
human behavior. Since a city size is known to have a major, yet often
nonlinear, impact on the human activity, it also becomes important to develop
scale-free metrics that capture qualitative city properties, beyond the effects
of scale. Recent availability of extensive datasets created by human activity
involving digital technologies creates new opportunities in this area. In this
paper we propose a novel approach of city scoring and classification based on
quantitative scale-free metrics related to economic activity of city residents,
as well as domestic and foreign visitors. It is demonstrated on the example of
Spain, but the proposed methodology is of a general character. We employ a new
source of large-scale ubiquitous data, which consists of anonymized countrywide
records of bank card transactions collected by one of the largest Spanish
banks. Different aspects of the classification reveal important properties of
Spanish cities, which significantly complement the pattern that might be
discovered with the official socioeconomic statistics.Comment: 10 pages, 7 figures, to be published in the proceedings of ASE
BigDataScience 2014 conferenc
Quantifying, Comparing Human Mobility Perturbation during Hurricane Sandy, Typhoon Wipha, Typhoon Haiyan
AbstractClimate change has intensified tropical cyclones, resulting in several recent catastrophic hurricanes and typhoons. Such disasters impose threats on populous coastal urban areas, and therefore, understanding and predicting human movements plays a critical role in disaster evacuation, response and relief. Despite its critical roles, limited research has focused on tropical cyclones and their influence on human mobility. Here, we studied how severe tropical storms could influence human mobility patterns in coastal urban populations using individuals’ movement data collected from Twitter. We selected three significant tropical storms, including Hurricane Sandy, Typhoon Wipha, and Typhoon Haiyan. We analyzed the human movement data before, during, and after each event, comparing the perturbed movement data to movement data from steady states. We also used different statistical analysis approaches to quantify the strength and duration of human mobility perturbation. The results suggest that tropical cyclones can significantly perturb human movements by changing travel frequencies and displacement probability distributions; however, the nature-derived Lévy Walk model still predominantly governs human mobility. Also, human mobility exhibits a surprisingly mild and brief perturbation for Hurricane Sandy and Typhoon Wipha, while the duration of disturbance was much longer for Typhoon Haiyan. Our finding that the Lévy Walk model can still predict human mobility suggests that bio-inspired examinations of human mobility patterns may uncover solutions to improve disaster evacuation, response and relief plans
From mobile phone data to the spatial structure of cities
Pervasive infrastructures, such as cell phone networks, enable to capture
large amounts of human behavioral data but also provide information about the
structure of cities and their dynamical properties. In this article, we focus
on these last aspects by studying phone data recorded during 55 days in 31
Spanish metropolitan areas. We first define an urban dilatation index which
measures how the average distance between individuals evolves during the day,
allowing us to highlight different types of city structure. We then focus on
hotspots, the most crowded places in the city. We propose a parameter free
method to detect them and to test the robustness of our results. The number of
these hotspots scales sublinearly with the population size, a result in
agreement with previous theoretical arguments and measures on employment
datasets. We study the lifetime of these hotspots and show in particular that
the hierarchy of permanent ones, which constitute the "heart" of the city, is
very stable whatever the size of the city. The spatial structure of these
hotspots is also of interest and allows us to distinguish different categories
of cities, from monocentric and "segregated" where the spatial distribution is
very dependent on land use, to polycentric where the spatial mixing between
land uses is much more important. These results point towards the possibility
of a new, quantitative classification of cities using high resolution
spatio-temporal data.Comment: 14 pages, 15 figure