Posts

Showing posts from June, 2011

New Paper: Self-Organization Leads to Supraoptimal Performance in Public Transportation Systems

Gershenson C (2011) Self-Organization Leads to Supraoptimal Performance in Public Transportation Systems. PLoS ONE6(6): e21469. http://dx.doi.org/10.1371/journal.pone.0021469


Abstract:
The performance of public transportation systems affects a large part of the population. Current theory assumes that passengers are served optimally when vehicles arrive at stations with regular intervals. In this paper, it is shown that self-organization can improve the performance of public transportation systems beyond the theoretical optimum by responding adaptively to local conditions. This is possible because of a “slower-is-faster” effect, where passengers wait more time at stations but total travel times are reduced. The proposed self-organizing method uses “antipheromones” to regulate headways, which are inspired by the stigmergy (communication via environment) of some ant colonies.

Epidemiology and social networks

Excerpt: By definition, noncommunicable diseases cannot be transmitted. However, there is recent evidence of the op- posite, involving a change of scientific paradigm. We have a notion that cardiovascular diseases, cancer and diabetes are noncontagious. Actually, there are no physical mechanisms that help spread these diseases. Nevertheless, risk factors of several noncommunicable diseases—such as obesity, al- coholism and smoking—are spread across populations.


Epidemiology and social networks, Carlos Gershenson, Cir Cir 2011;79:199-200
Full Text: In English: [pdf] [html] En EspaƱol: [pdf] [html]