[Forum SIS] Seminario: Samuele Stivanello, Ecology of human activities

[Antonio Pievatolo]

Lunedi' 17 giugno alle 14:45, presso il CNR-IMATI, in via A. Corti, 12, 
Milano, Aula Pentagonale edificio Bassini II piano, si terrà il seguente 
seminario:

Samuele Stivanello, Dipartimento di Matematica, Universita' di Padova

Title: Ecology of human activities

Abstract: One of the most studied macro-ecological pattern is the 
Relative Species Abundance (RSA), describing the distribution of the 
population among species. Various natural ecosystems share a common 
shape of the empirical RSA and through years ecologists have used 
several recipes - some of them are rule of thumb prescriptions - to 
determine global RSA features from local information. Recently our group 
has developed a rigorous statistical framework able to predict global 
scale biodiversity from scattered local plots ([2], [3]). Such a 
framework is derived from a simple mathematical model informed by basic 
biological assumptions. In this talk we illustrate how to 
adapt/generalize such an approach to human activities. In particular we 
consider four datasets of man-made systems and/or network mediated human 
activities: e-mail communication, Twitter posts, Wikipedia articles and 
Gutenberg books. Once we set the proper correspondence to what we 
consider species and individuals of a species, our approach reveals RSA 
is scale-free in each mentioned dataset with a power law form maintained 
- with roughly the same exponent - through the different human 
activities considered. In turn, RSA scale-invariance allows us to use 
activity information on local scale to predict hidden features of the 
human dynamics at the global scale. E-mail communication is particular 
relevant to illustrate our method as well as our results and possible 
applications. We consider the senders’ activity network where each node 
is a sender and a directed link from node A to node B represents an 
email issued from user A to user B. We set the identity of a sender to 
identify the species and the number of sent emails to be the individuals 
pertaining to a species. Thus, for instance, if user A has sent n emails 
we say that the species A has n individuals. Now, suppose an observer 
has access to a small sample of sent emails, or equivalently to partial 
information on links and nodes of the email communication network. Our 
method is capable to infer the number of nodes (i.e. the number of 
users) and the degree distribution (i.e. the topology) of the whole 
network, thus revealing features of the dynamics unknown to the 
observer. Moreover, our framework predicts how the number of users grows 
with the number of links recorded, which represents another well known 
pattern in ecology called the Species-Accumulation Curve (SAC). These 
findings may have applications in resource management, optimal network 
design and information diffusion on graphs. This is a work in 
collaboration with M. Formentin, A. Tovo and S. Favaro [1].

[1] M. Formentin, A. Tovo, S. Stivanello, S. Favaro. Ecology of human 
activities. In preparation, 2019+.
[2] A. Tovo, S. Suweis, M. Formentin, M. Favretti, I. Volkov, J. R. 
Banavar, S. Azaele, A. Maritan. Upscaling species richness and 
abundances in tropical forests. Science Advances 3 (10) (2017) e1701438.
[3] A. Tovo, M. Formentin, S. Suweis, S. Stivanello, S. Azaele. A. 
Maritan. Inferring macro-ecological patterns from local species’ 
occurrences. Methods in Ecology and Evolution, submitted, 2019.

-- 
Dr Antonio Pievatolo
IMATI-CNR
http://www.imati.cnr.it/joomla/index.php/people?layout=edit&id=101
ph. +39 02 23699 520

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.stat.unipg.it/pipermail/sis/attachments/20190611/3d26a2df/attachment-0001.html>