Print

Print


*****  To join INSNA, visit http://www.insna.org  *****

Thank you, Barry, for writing about our work--this is flattering.

Since the article has not appeared in PNAS yet (although it should have)
I am posting the link to a preprint, so that whatever discussion ensues
in the list is based on the science and not on the press release:

http://amaral.chem-eng.northwestern.edu/publications/missing-and-spurious-interactions-and-reconstruction-complex-networks/

Elisa: You are absolutely right--what we discuss (and, more importantly,
test) in the article is unbiased errors. We explicitly note this fact
and, in the final discussion, briefly touch on how we think our approach
should be extended to correlated errors.

Roger

Bienenstock, Elisa wrote:
> *****  To join INSNA, visit http://www.insna.org  *****
> 
> Thank you! 
> 
> Very interesting, but I am confused about how to apply this type of approach when the data available is not only missing, but may be missing due to some systematic collection bias.  
> 
> -----Original Message-----
> From: Social Networks Discussion Forum [mailto:[log in to unmask]] On Behalf Of Barry Wellman
> Sent: Friday, December 11, 2009 6:27 PM
> To: [log in to unmask]
> Subject: [SOCNET] getting the "true" network
> 
> *****  To join INSNA, visit http://www.insna.org  *****
> 
> no theory needed
> 
> 
>  Barry Wellman
>  _______________________________________________________________________
> 
>   S.D. Clark Professor of Sociology, FRSC               NetLab Director
>   Department of Sociology                  725 Spadina Avenue, Room 388
>   University of Toronto   Toronto Canada M5S 2J4   twitter:barrywellman
>   http://www.chass.utoronto.ca/~wellman             fax:+1-416-978-3963
>   Updating history:      http://chass.utoronto.ca/oldnew/cybertimes.php
>  _______________________________________________________________________
> 
> Facebook (and Systems Biologists) Take Note: Network Analysis Reveals True
> Connections
> Northwestern University News Center (IL) (12/07/09) Fellman, Megan
> 
> Northwestern University researchers Roger Guimera and Marta Sales-Pardo
> have developed a universal method that can correctly analyze a variety of
> complex networks.  The researchers tested their method on a range of five
> networks: a karate club, a social network of dolphins, the neural network
> of a worm, the air transportation network of Eastern Europe, and the
> metabolic network of Escherichia coli.  For each of the five networks, the
> researchers introduced errors and applied an algorithm to the distorted
> network.  Each time, the algorithm created a new network with the errors
> separated out, and each new network construction was closer to the
> original true network.  "The flexibility of our approach, along with its
> generality and its performance, will make it applicable to many areas
> where network data reliability is a source of concern," say Guimera and
> Sales-Pardo. The central idea to the new method is that, even though every
> network has unique characteristics, they all have nodes that can be put
> into specific groups, with the nodes connecting to each other based on
> group membership.  The method averages all possible groupings of the nodes
> and gives each group a weight that reflects its explanatory power.
> "There are many ways to map nodes in a network, not just one," says
> Sales-Pardo.  "We consider all the possible ways.  By taking the sum of
> them all, we can identify both missing and spurious connections."
> 
> http://www.northwestern.edu/newscenter/stories/2009/12/networks.html
> 
> _____________________________________________________________________
> SOCNET is a service of INSNA, the professional association for social
> network researchers (http://www.insna.org). To unsubscribe, send
> an email message to [log in to unmask] containing the line
> UNSUBSCRIBE SOCNET in the body of the message.
> 
> _____________________________________________________________________
> SOCNET is a service of INSNA, the professional association for social
> network researchers (http://www.insna.org). To unsubscribe, send
> an email message to [log in to unmask] containing the line
> UNSUBSCRIBE SOCNET in the body of the message.

-- 
Roger Guimera
Chemical & Biological Engineering   Phone: +1-847-491-2778
Northwestern University                    +1-847-467-1386
2145 Sheridan Road, Room E-136      Fax:   +1-847-491-3728
Evanston, IL 60208, USA             http://amaral.northwestern.edu/roger

_____________________________________________________________________
SOCNET is a service of INSNA, the professional association for social
network researchers (http://www.insna.org). To unsubscribe, send
an email message to [log in to unmask] containing the line
UNSUBSCRIBE SOCNET in the body of the message.