Widescreen Test Pattern (16:9)

Aspect Ratio TestTest

(Should appear circular)

16x9

4x3

Powered by

COMPLEX NETWORKSCOMPLEX NETWORKS: FROM DATA TOFROM DATA TO MODELS by Arturo Araujo

Data of people’s activitiesData of people s activities Is becoming ever more detailedIs becoming ever more detailed

In industrial countries, there is almost 100% ,mobile-phone penetration

If you have a mobile phone:If you have a mobile phone:Your carrier knows your whereaboutsHas a list of your friendsKnows how often you’ve kept in touch

ImportanceImportance

H t it t iHuge opportunity to scienceAccess to patterns of human behavior

Quantifying and understanding such patternp

Help design better public transportSafer public spaces,Control a disease outbreakControl a disease outbreak

Picture : http://chronicle.augusta.com/stories/110697/fea_cellphonemyths.html

ProblemProblemLack of robust Models

l i i th ttexplaining the patterns

Quantify Social GroupQuantify Social Group Evolution?

Describe the Movement of People?

Picture : http://www.flickr.com/photos/livingjuicy/258830130/

Group EvolutionGroup Evolution

SocialSocialCollaboration between scientists

CommunicationC ll b t M bil h UCalls between Mobile-phone Users

Community StructureCommunity Structure

What can Happen?What can Happen?

Community StructureCommunity Structure

Correlation Between StatesCorrelation Between States

Co-authorshipCo authorshipAverage Life time

CorrelationPopulation Size

Mobile-Phone UsersMobile Phone Users

Features of Community EvolutionFeatures of Community EvolutionSmall CommunitiesSmall Communities

Optimal to have static, time-independent membershipmembership

L C itiLarge CommunitiesOptimal to be dynamic, continually changing

b himembership

ThoughtsThoughtsApply it to Communities you are familiar withApply it to Communities you are familiar with

F lFor exampleMembers of a school or a company changeThe school /company will be detectable as a community at any time!

What’s Next?What s Next?

Movement of individuals

Good luck!

SourcesSourcesComplex networks: From data to models

Nature Physics 3, 224 - 225 (April 2007)Marta C. González and Albert-László Barabási

Q tif i i l l tiQuantifying social group evolutionNature 446, 664-667 (April 2007)G. Palla, A.-L. Barabási and T. Vicsek

Center for Complex Network Research http://www.nd.edu/~networks/

Wikipedia Article: Complex Networkshttp://en.wikipedia.org/wiki/Complex_network

Scale-free networkScale free network

some nodes act as “highlysome nodes act as highly connected hubs”

most nodes are of low degree

the degree distribution of these networks has no characteristic scalecharacteristic scale