9 results on '"Zbigniew Smoreda"'
Search Results
2. A method to estimate population densities and electricity consumption from mobile phone data in developing countries.
- Author
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Hadrien Salat, Zbigniew Smoreda, and Markus Schläpfer
- Subjects
Medicine ,Science - Abstract
High quality census data are not always available in developing countries. Instead, mobile phone data are becoming a popular proxy to evaluate the density, activity and social characteristics of a population. They offer additional advantages: they are updated in real-time, include mobility information and record visitors' activity. However, we show with the example of Senegal that the direct correlation between the average phone activity and both the population density and the nighttime lights intensity may be insufficiently high to provide an accurate representation of the situation. There are reasons to expect this, such as the heterogeneity of the market share or the particular granularity of the distribution of cell towers. In contrast, we present a method based on the daily, weekly and yearly phone activity curves and on the network characteristics of the mobile phone data, that allows to estimate more accurately such information without compromising people's privacy. This information can be vital for development and infrastructure planning. In particular, this method could help to reduce significantly the logistic costs of data collection in the particularly budget-constrained context of developing countries.
- Published
- 2020
- Full Text
- View/download PDF
3. On the use of human mobility proxies for modeling epidemics.
- Author
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Michele Tizzoni, Paolo Bajardi, Adeline Decuyper, Guillaume Kon Kam King, Christian M Schneider, Vincent Blondel, Zbigniew Smoreda, Marta C González, and Vittoria Colizza
- Subjects
Biology (General) ,QH301-705.5 - Abstract
Human mobility is a key component of large-scale spatial-transmission models of infectious diseases. Correctly modeling and quantifying human mobility is critical for improving epidemic control, but may be hindered by data incompleteness or unavailability. Here we explore the opportunity of using proxies for individual mobility to describe commuting flows and predict the diffusion of an influenza-like-illness epidemic. We consider three European countries and the corresponding commuting networks at different resolution scales, obtained from (i) official census surveys, (ii) proxy mobility data extracted from mobile phone call records, and (iii) the radiation model calibrated with census data. Metapopulation models defined on these countries and integrating the different mobility layers are compared in terms of epidemic observables. We show that commuting networks from mobile phone data capture the empirical commuting patterns well, accounting for more than 87% of the total fluxes. The distributions of commuting fluxes per link from mobile phones and census sources are similar and highly correlated, however a systematic overestimation of commuting traffic in the mobile phone data is observed. This leads to epidemics that spread faster than on census commuting networks, once the mobile phone commuting network is considered in the epidemic model, however preserving to a high degree the order of infection of newly affected locations. Proxies' calibration affects the arrival times' agreement across different models, and the observed topological and traffic discrepancies among mobility sources alter the resulting epidemic invasion patterns. Results also suggest that proxies perform differently in approximating commuting patterns for disease spread at different resolution scales, with the radiation model showing higher accuracy than mobile phone data when the seed is central in the network, the opposite being observed for peripheral locations. Proxies should therefore be chosen in light of the desired accuracy for the epidemic situation under study.
- Published
- 2014
- Full Text
- View/download PDF
4. Delineating geographical regions with networks of human interactions in an extensive set of countries.
- Author
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Stanislav Sobolevsky, Michael Szell, Riccardo Campari, Thomas Couronné, Zbigniew Smoreda, and Carlo Ratti
- Subjects
Medicine ,Science - Abstract
Large-scale networks of human interaction, in particular country-wide telephone call networks, can be used to redraw geographical maps by applying algorithms of topological community detection. The geographic projections of the emerging areas in a few recent studies on single regions have been suggested to share two distinct properties: first, they are cohesive, and second, they tend to closely follow socio-economic boundaries and are similar to existing political regions in size and number. Here we use an extended set of countries and clustering indices to quantify overlaps, providing ample additional evidence for these observations using phone data from countries of various scales across Europe, Asia, and Africa: France, the UK, Italy, Belgium, Portugal, Saudi Arabia, and Ivory Coast. In our analysis we use the known approach of partitioning country-wide networks, and an additional iterative partitioning of each of the first level communities into sub-communities, revealing that cohesiveness and matching of official regions can also be observed on a second level if spatial resolution of the data is high enough. The method has possible policy implications on the definition of the borderlines and sizes of administrative regions.
- Published
- 2013
- Full Text
- View/download PDF
5. Weather effects on mobile social interactions: a case study of mobile phone users in Lisbon, Portugal.
- Author
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Santi Phithakkitnukoon, Tuck W Leong, Zbigniew Smoreda, and Patrick Olivier
- Subjects
Medicine ,Science - Abstract
The effect of weather on social interactions has been explored through the analysis of a large mobile phone use dataset. Time spent on phone calls, numbers of connected social ties, and tie strength were used as proxies for social interactions; while weather conditions were characterized in terms of temperature, relative humidity, air pressure, and wind speed. Our results are based on the analysis of a full calendar year of data for 22,696 mobile phone users (53.2 million call logs) in Lisbon, Portugal. The results suggest that different weather parameters have correlations to the level and character of social interactions. We found that although weather did not show much influence upon people's average call duration, the likelihood of longer calls was found to increase during periods of colder weather. During periods of weather that were generally considered to be uncomfortable (i.e., very cold/warm, very low/high air pressure, and windy), people were found to be more likely to communicate with fewer social ties. Despite this tendency, we found that people are more likely to maintain their connections with those they have strong ties with much more than those of weak ties. This study sheds new light on the influence of weather conditions on social relationships and how mobile phone data can be used to investigate the influence of environmental factors on social dynamics.
- Published
- 2012
- Full Text
- View/download PDF
6. Socio-geography of human mobility: a study using longitudinal mobile phone data.
- Author
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Santi Phithakkitnukoon, Zbigniew Smoreda, and Patrick Olivier
- Subjects
Medicine ,Science - Abstract
A relationship between people's mobility and their social networks is presented based on an analysis of calling and mobility traces for one year of anonymized call detail records of over one million mobile phone users in Portugal. We find that about 80% of places visited are within just 20 km of their nearest (geographical) social ties' locations. This figure rises to 90% at a 'geo-social radius' of 45 km. In terms of their travel scope, people are geographically closer to their weak ties than strong ties. Specifically, they are 15% more likely to be at some distance away from their weak ties than strong ties. The likelihood of being at some distance from social ties increases with the population density, and the rates of increase are higher for shorter geo-social radii. In addition, we find that area population density is indicative of geo-social radius where denser areas imply shorter radii. For example, in urban areas such as Lisbon and Porto, the geo-social radius is approximately 7 km and this increases to approximately 15 km for less densely populated areas such as Parades and Santa Maria da Feira.
- Published
- 2012
- Full Text
- View/download PDF
7. Interplay between telecommunications and face-to-face interactions: a study using mobile phone data.
- Author
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Francesco Calabrese, Zbigniew Smoreda, Vincent D Blondel, and Carlo Ratti
- Subjects
Medicine ,Science - Abstract
In this study we analyze one year of anonymized telecommunications data for over one million customers from a large European cellphone operator, and we investigate the relationship between people's calls and their physical location. We discover that more than 90% of users who have called each other have also shared the same space (cell tower), even if they live far apart. Moreover, we find that close to 70% of users who call each other frequently (at least once per month on average) have shared the same space at the same time--an instance that we call co-location. Co-locations appear indicative of coordination calls, which occur just before face-to-face meetings. Their number is highly predictable based on the amount of calls between two users and the distance between their home locations--suggesting a new way to quantify the interplay between telecommunications and face-to-face interactions.
- Published
- 2011
- Full Text
- View/download PDF
8. Delineating geographical regions with networks of human interactions in an extensive set of countries
- Author
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Carlo Ratti, Thomas Couronné, Stanislav Sobolevsky, Zbigniew Smoreda, Michael Szell, Riccardo Campari, Massachusetts Institute of Technology. Department of Urban Studies and Planning, Massachusetts Institute of Technology. SENSEable City Laboratory, Sobolevsky, Stanislav, Szell, Michael, Campari, Riccardo, and Ratti, Carlo
- Subjects
FOS: Computer and information sciences ,Matching (statistics) ,Physics - Physics and Society ,Asia ,FOS: Physical sciences ,lcsh:Medicine ,Cote d ivoire ,Physics and Society (physics.soc-ph) ,Group cohesiveness ,Human interaction ,Environmental protection ,Phone ,Residence Characteristics ,Regional science ,Humans ,Cluster analysis ,Set (psychology) ,lcsh:Science ,Social and Information Networks (cs.SI) ,Multidisciplinary ,Geography ,lcsh:R ,Social Support ,Computer Science - Social and Information Networks ,Europe ,Africa ,lcsh:Q ,Geographical maps ,Algorithms ,Research Article - Abstract
Large-scale networks of human interaction, in particular country-wide telephone call networks, can be used to redraw geographical maps by applying algorithms of topological community detection. The geographic projections of the emerging areas in a few recent studies on single regions have been suggested to share two distinct properties: first, they are cohesive, and second, they tend to closely follow socio-economic boundaries and are similar to existing political regions in size and number. Here we use an extended set of countries and clustering indices to quantify overlaps, providing ample additional evidence for these observations using phone data from countries of various scales across Europe, Asia, and Africa: France, the UK, Italy, Belgium, Portugal, Saudi Arabia, and Ivory Coast. In our analysis we use the known approach of partitioning country-wide networks, and an additional iterative partitioning of each of the first level communities into sub-communities, revealing that cohesiveness and matching of official regions can also be observed on a second level if spatial resolution of the data is high enough. The method has possible policy implications on the definition of the borderlines and sizes of administrative regions., National Science Foundation (U.S.), Singapore-MIT Alliance for Research and Technology
- Published
- 2013
9. Weather effects on mobile social interactions: a case study of mobile phone users in Lisbon, Portugal
- Author
-
Zbigniew Smoreda, Patrick Olivier, Santi Phithakkitnukoon, and Tuck Wah Leong
- Subjects
General Science & Technology ,lcsh:Medicine ,Wind ,Biology ,Social and Behavioral Sciences ,Wind speed ,Behavioral Ecology ,Interpersonal relationship ,Sociology ,Phone ,Psychology ,Humans ,Interpersonal Relations ,lcsh:Science ,Weather ,Call duration ,Behavior ,Social Research ,Multidisciplinary ,Ecology ,Portugal ,Verbal Behavior ,lcsh:R ,Temperature ,Humidity ,Advertising ,Strong ties ,Sociometry ,Communications ,Interpersonal ties ,Social dynamics ,Social Networks ,Computational Sociology ,Mobile phone ,Cellular Phone ,Social Systems ,lcsh:Q ,Cell Phone ,Research Article - Abstract
The effect of weather on social interactions has been explored through the analysis of a large mobile phone use dataset. Time spent on phone calls, numbers of connected social ties, and tie strength were used as proxies for social interactions; while weather conditions were characterized in terms of temperature, relative humidity, air pressure, and wind speed. Our results are based on the analysis of a full calendar year of data for 22,696 mobile phone users (53.2 million call logs) in Lisbon, Portugal. The results suggest that different weather parameters have correlations to the level and character of social interactions. We found that although weather did not show much influence upon people's average call duration, the likelihood of longer calls was found to increase during periods of colder weather. During periods of weather that were generally considered to be uncomfortable (i.e., very cold/warm, very low/high air pressure, and windy), people were found to be more likely to communicate with fewer social ties. Despite this tendency, we found that people are more likely to maintain their connections with those they have strong ties with much more than those of weak ties. This study sheds new light on the influence of weather conditions on social relationships and how mobile phone data can be used to investigate the influence of environmental factors on social dynamics. © 2012 Phithakkitnukoon et al.
- Published
- 2012
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