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Individual mobility

This article is about demographic research term. For term used in social identity theory, see Social identity theory § Individual mobility.
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Individual human mobility is the study that describes how individual humans move within a network or system.[1] The concept has been studied in a number of fields originating in the study of demographics. Understanding human mobility has many applications in diverse areas, including spread of diseases,[2][3] mobile viruses,[4] city planning,[5][6][7] traffic engineering,[8][9] financial market forecasting,[10] and nowcasting of economic well-being.[11][12]

Data

In recent years, there has been a surge in large data sets available on human movements. These data sets are usually obtained from cell phone or GPS data, with varying degrees of accuracy. For example, cell phone data is usually recorded whenever a call or a text message has been made or received by the user, and contains the location of the tower that the phone has connected to as well as the time stamp.[13] In urban areas, user and the telecommunication tower might be only a few hundred meters away from each other, while in rural areas this distance might well be in region of a few kilometers. Therefore, there is varying degree of accuracy when it comes to locating a person using cell phone data. These datasets are anonymized by the phone companies so as to hide and protect the identity of actual users. As example of its usage, researchers [13] used the trajectory of 100,000 cell phone users within a period of six months, while in much larger scale [14] trajectories of three million cell phone users were analyzed. GPS data are usually much more accurate even though they usually are, because of privacy concerns, much harder to acquire. Massive amounts of GPS data describing human mobility are produced, for example, by on-board GPS devices on private vehicles.[15][16] The GPS device automatically turns on when the vehicle starts, and the sequence of GPS points the device produces every few seconds forms a detailed mobility trajectory of the vehicle. Some recent scientific studies compared the mobility patterns emerged from mobile phone data with those emerged from GPS data.[15][16][17]

Researchers have been able to extract very detailed information about the people whose data are made available to public. This has sparked a great amount of concern about privacy issues. As an example of liabilities that might happen, New York City released 173 million individual taxi trips. City officials used a very weak cryptography algorithm to anonymize the license number and medallion number, which is an alphanumeric code assigned to each taxi cab.[18] This made it possible for hackers to completely de-anonymize the dataset, and even some were able to extract detailed information about specific passengers and celebrities, including their origin and destination and how much they tipped.[18][19]

Characteristics

At the large scale, when the behaviour is modelled over a period of relatively long duration (e.g. more than one day), human mobility can be described by three major components:

  • trip distance distribution
  • radius of gyration
  • number of visited locations

Brockmann,[20] by analysing banknotes, found that the probability of travel distance follows a scale-free random walk known as Lévy flight of form where . This was later confirmed by two studies that used cell phone data[13] and GPS data to track users.[15] The implication of this model is that, as opposed to other more traditional forms of random walks such as brownian motion, human trips tend to be of mostly short distances with a few long distance ones. In brownian motion, the distribution of trip distances are govern by a bell-shaped curve, which means that the next trip is of a roughly predictable size, the average, where in Lévy flight it might be an order of magnitude larger than the average.

Some people are inherently inclined to travel longer distances than the average, and the same is true for people with lesser urge for movement. Radius of gyration is used to capture just that and it indicates the characteristic distance travelled by a person during a time period t.[13] Each user, within his radius of gyration , will choose his trip distance according to .

The third component models the fact that humans tend to visit some locations more often than what would have happened under a random scenario. For example, home or workplace or favorite restaurants are visited much more than many other places in a user's radius of gyration. It has been discovered that where , which indicates a sublinear growth in different number of places visited by an individual . These three measures capture the fact that most trips happen between a limited number of places, with less frequent travels to places outside of an individual's radius of gyration.

Predictability

Although the human mobility is modeled as a random process, it is surprisingly predictable. By measuring the entropy of each person's movement, it has been shown [14] that there is a 93% potential predictability. This means that although there is a great variance in type of users and the distances that each of them travel, the overall characteristic of them is highly predictable. Implication of it is that in principle, it is possible to accurately model the processes that are dependent on human mobility patterns, such as disease or mobile virus spreading patterns.[21][22][23]

On individual scale, daily human mobility can be explained by only 17 Network motifs. Each individual, shows one of these motifs characteristically, over a period of several months. This opens up the possibility to reproduce daily individual mobility using a tractable analytical model[24]

Applications

Infectious diseases spread across the globe usually because of long-distance travels of carriers of the disease. These long-distance travels are made using air transportation systems and it has been shown that "network topology, traffic structure, and individual mobility patterns are all essential for accurate predictions of disease spreading".[21] On a smaller spatial scale the regularity of human movement patterns and its temporal structure should be taken into account in models of infectious disease spread.[25] Cellphone viruses that are transmitted via bluetooth are greatly dependent on the human interaction and movements. With more people using similar operating systems for their cellphones, it's becoming much easier to have a virus epidemic.[22]

In Transportation Planning, leveraging the characteristics of human movement, such as tendency to travel short distances with few but regular bursts of long-distance trips, novel improvements have been made to Trip distribution models, specifically to Gravity model of migration[26]

See also

References

  1. ^ Keyfitz, Nathan (1973). "Individual Mobility in a Stationary Population". Population Studies. 27 (July 1, 1973): 335–352. doi:10.2307/2173401. JSTOR 2173401. PMID 22085100.
  2. ^ Colizza, V.; Barrat, A.; Barthélémy, M.; Valleron, A.-J.; Vespignani, A. (2007). "Modeling the worldwide spread of pandemic influenza: baseline case and containment interventions". PLOS Medicine. 4 (1): 95–110. arXiv:q-bio/0701038. Bibcode:2007q.bio.....1038C. doi:10.1371/journal.pmed.0040013. PMC 1779816. PMID 17253899.
  3. ^ Hufnagel, L.; Brockmann, D.; Geisel, T. (2004). "Forecast and control of epidemics in a globalized world". Proc. Natl. Acad. Sci. USA. 101 (42): 15124–15129. arXiv:cond-mat/0410766. Bibcode:2004PNAS..10115124H. doi:10.1073/pnas.0308344101. PMC 524041. PMID 15477600.
  4. ^ Pastor-Satorras, Romualdo; Vespignani, Alessandro (2001-04-02). "Epidemic Spreading in Scale-Free Networks". Physical Review Letters. 86 (14): 3200–3203. arXiv:cond-mat/0010317. Bibcode:2001PhRvL..86.3200P. doi:10.1103/physrevlett.86.3200. ISSN 0031-9007. PMID 11290142. S2CID 16298768.
  5. ^ Horner, M. W.; O'Kelly, M. E. S (2001). "Embedding economies of scale concepts for hub networks design". J. Transp. Geogr. 9 (4): 255–265. doi:10.1016/s0966-6923(01)00019-9.
  6. ^ Inferring land use from mobile phone activity JL Toole, M Ulm, MC González, D Bauer - Proceedings of the ACM SIGKDD international …, 2012
  7. ^ Rozenfeld, H. D.; et al. (2008). "Laws of population growth". Proc. Natl. Acad. Sci. USA. 105 (48): 18702–18707. arXiv:0808.2202. Bibcode:2008PNAS..10518702R. doi:10.1073/pnas.0807435105. PMC 2596244. PMID 19033186.
  8. ^ Wang, Pu; Hunter, Timothy; Bayen, Alexandre M.; Schechtner, Katja; González, Marta C. (2012). "Understanding Road Usage Patterns in Urban Areas". Scientific Reports. 2 (1). Springer Science and Business Media LLC: 1001. arXiv:1212.5327. Bibcode:2012NatSR...2E1001W. doi:10.1038/srep01001. ISSN 2045-2322. PMC 3526957. PMID 23259045.
  9. ^ Krings, Gautier; Calabrese, Francesco; Ratti, Carlo; Blondel, Vincent D (2009-07-14). "Urban gravity: a model for inter-city telecommunication flows". Journal of Statistical Mechanics: Theory and Experiment. 2009 (7). IOP Publishing: L07003. arXiv:0905.0692. doi:10.1088/1742-5468/2009/07/l07003. ISSN 1742-5468. S2CID 1445486.
  10. ^ Gabaix, X.; Gopikrishnan, P.; Plerou, V.; Stanley, H. E. (2003). "A theory of power-law distributions in financial market fluctuations". Nature. 423 (6937): 267–270. Bibcode:2003Natur.423..267G. doi:10.1038/nature01624. PMID 12748636. S2CID 1263236.
  11. ^ Stefano Marchetti; et al. (Jun 2015). "Small Area Model-Based Estimators Using Big Data Sources". Journal of Official Statistics. 31 (2): 263–281. doi:10.1515/jos-2015-0017. hdl:11568/754495.
  12. ^ L. Pappalardo et al., Using Big Data to study the link between human mobility and socio-economic development, Proceedings of the 2015 IEEE International conference on Big Data, Santa Clara, CA, USA, 2015.
  13. ^ a b c d González, Marta C.; Hidalgo, César A.; Barabási, Albert-László (2008). "Understanding individual human mobility patterns". Nature. 453 (7196): 779–782. arXiv:0806.1256. Bibcode:2008Natur.453..779G. doi:10.1038/nature06958. ISSN 0028-0836. PMID 18528393. S2CID 4419468.
  14. ^ a b Limits of predictability in human mobility. C Song, Z Qu, N Blumm, AL Barabási - Science, 2010
  15. ^ a b c Luca Pappalardo; et al. (29 January 2013). "Understanding the patterns of car travel". European Physical Journal ST. 215 (1): 61–73. Bibcode:2013EPJST.215...61P. doi:10.1140/epjst/e2013-01715-5. S2CID 120805149.
  16. ^ a b Luca Pappalardo; et al. (8 September 2015). "Returners and Explorers dichotomy in Human Mobility". Nature Communications. 6: 8166. Bibcode:2015NatCo...6.8166P. doi:10.1038/ncomms9166. PMC 4569739. PMID 26349016.
  17. ^ L. Pappalardo et al., Comparing general mobility and mobility by car, BRICS Countries Congress (BRICS-CCI) and 11th Brazilian Congress (CBIC) on Computational Intelligence, 2013.
  18. ^ a b "Public NYC Taxicab Database Lets You See How Celebrities Tip". Archived from the original on 2014-11-18. Retrieved 2014-11-15.
  19. ^ Hern, Alex (2014-06-27). "New York taxi details can be extracted from anonymised data, researchers say". The Guardian.
  20. ^ Brockmann, D.; Hufnagel, L.; Geisel, T. (2006). "The scaling laws of human travel". Nature. 439 (7075): 462–465. arXiv:cond-mat/0605511. Bibcode:2006Natur.439..462B. doi:10.1038/nature04292. ISSN 0028-0836. PMID 16437114. S2CID 4330122.
  21. ^ a b Nicolaides, Christos; Cueto-Felgueroso, Luis; González, Marta C.; Juanes, Ruben (2012-07-19). Vespignani, Alessandro (ed.). "A Metric of Influential Spreading during Contagion Dynamics through the Air Transportation Network". PLOS ONE. 7 (7). Public Library of Science (PLoS): e40961. Bibcode:2012PLoSO...740961N. doi:10.1371/journal.pone.0040961. ISSN 1932-6203. PMC 3400590. PMID 22829902.
  22. ^ a b Wang, P.; Gonzalez, M. C.; Hidalgo, C. A.; Barabasi, A.-L. (2009-04-01). "Understanding the Spreading Patterns of Mobile Phone Viruses". Science. 324 (5930): 1071–1076. arXiv:0906.4567. Bibcode:2009Sci...324.1071W. doi:10.1126/science.1167053. ISSN 0036-8075. PMID 19342553. S2CID 11081201.
  23. ^ Colizza, Vittoria; Barrat, Alain; Barthélemy, Marc; Vespignani, Alessandro (2007-11-21). "Predictability and epidemic pathways in global outbreaks of infectious diseases: the SARS case study". BMC Medicine. 5 (1): 34. arXiv:0801.2261. doi:10.1186/1741-7015-5-34. ISSN 1741-7015. PMC 2213648. PMID 18031574.
  24. ^ Schneider, Christian M.; Belik, Vitaly; Couronné, Thomas; Smoreda, Zbigniew; González, Marta C. (2013-07-06). "Unravelling daily human mobility motifs". Journal of the Royal Society Interface. 10 (84). The Royal Society: 20130246. doi:10.1098/rsif.2013.0246. ISSN 1742-5689. PMC 3673164. PMID 23658117.
  25. ^ Belik, Vitaly; Geisel, Theo; Brockmann, Dirk (2011-08-08). "Natural Human Mobility Patterns and Spatial Spread of Infectious Diseases". Physical Review X. 1 (1): 011001. arXiv:1103.6224. Bibcode:2011PhRvX...1a1001B. doi:10.1103/physrevx.1.011001. ISSN 2160-3308.
  26. ^ Simini, Filippo; González, Marta C.; Maritan, Amos; Barabási, Albert-László (2012-02-26). "A universal model for mobility and migration patterns". Nature. 484 (7392): 96–100. arXiv:1111.0586. Bibcode:2012Natur.484...96S. doi:10.1038/nature10856. ISSN 0028-0836. PMID 22367540. S2CID 4431030.
Quelle: http://en.wikipedia.org/wiki/Individual_mobility