31,129 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
Location Prediction: Communities Speak Louder than Friends
Humans are social animals, they interact with different communities of
friends to conduct different activities. The literature shows that human
mobility is constrained by their social relations. In this paper, we
investigate the social impact of a person's communities on his mobility,
instead of all friends from his online social networks. This study can be
particularly useful, as certain social behaviors are influenced by specific
communities but not all friends. To achieve our goal, we first develop a
measure to characterize a person's social diversity, which we term `community
entropy'. Through analysis of two real-life datasets, we demonstrate that a
person's mobility is influenced only by a small fraction of his communities and
the influence depends on the social contexts of the communities. We then
exploit machine learning techniques to predict users' future movement based on
their communities' information. Extensive experiments demonstrate the
prediction's effectiveness.Comment: ACM Conference on Online Social Networks 2015, COSN 201
Housing Search in the Age of Big Data: Smarter Cities or the Same Old Blind Spots?
Housing scholars stress the importance of the information environment in shaping housing search behavior and outcomes. Rental listings have increasingly moved online over the past two decades and, in turn, online platforms like Craigslist are now central to the search process. Do these technology platforms serve as information equalizers or do they reflect traditional information inequalities that correlate with neighborhood sociodemographics? We synthesize and extend analyses of millions of US Craigslist rental listings and find they supply significantly different volumes, quality, and types of information in different communities. Technology platforms have the potential to broaden, diversify, and equalize housing search information, but they rely on landlord behavior and, in turn, likely will not reach this potential without a significant redesign or policy intervention. Smart cities advocates hoping to build better cities through technology must critically interrogate technology platforms and big data for systematic biases
Harmonising Databases for the Cross National Study of Internal Migration: Lessons from Australia and Britain
This project involves the development of a Web interface to origin-destination statistics from the 1991 Census (in a form that will be compatible with planned 2001 outputs). It provides the user with a set of screen-based tools for setting the parameters governing each data extraction (data set, areas, variables) in the form of a query. Traffic light icons are used to signal what the user has set so far and what remains to be done. There are options to extract different types of flow data and to generate output in different formats. The system can now be used to access the interaction flow data contained in the 1991 Special Migration Statistics Sets 1 and 2 and Special Workplace Statistics Set C. WICID has been demonstrated at the Origin-Destination Statistics Roadshows organised by GRO Scotland and held during May/June 2000 and the Census Offices have expressed interest in using the software in the Census Access Project
Comparing and modeling land use organization in cities
The advent of geolocated ICT technologies opens the possibility of exploring
how people use space in cities, bringing an important new tool for urban
scientists and planners, especially for regions where data is scarce or not
available. Here we apply a functional network approach to determine land use
patterns from mobile phone records. The versatility of the method allows us to
run a systematic comparison between Spanish cities of various sizes. The method
detects four major land use types that correspond to different temporal
patterns. The proportion of these types, their spatial organization and scaling
show a strong similarity between all cities that breaks down at a very local
scale, where land use mixing is specific to each urban area. Finally, we
introduce a model inspired by Schelling's segregation, able to explain and
reproduce these results with simple interaction rules between different land
uses.Comment: 9 pages, 6 figures + Supplementary informatio
Geometrical interpretation of fluctuating hydrodynamics in diffusive systems
We discuss geometric formulations of hydrodynamic limits in diffusive
systems. Specifically, we describe a geometrical construction in the space of
density profiles --- the Wasserstein geometry --- which allows the
deterministic hydrodynamic evolution of the systems to be related to steepest
descent of the free energy, and show how this formulation can be related to
most probable paths of mesoscopic dissipative systems. The geometric viewpoint
is also linked to fluctuating hydrodynamics of these systems via a saddle point
argument.Comment: 19 page
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