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Social Networks. Obesity as a networked concept. The same goes for smoking …. www.tue-tm.org/INAM. All course info, literature, slides, and messages can be found here. Check regularly!. Today. Course design and content Introduction to network analysis and concepts. Lecturers.
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www.tue-tm.org/INAM • All course info, literature, slides, and messages can be found here. Check regularly!
Today • Course design and content • Introduction to network analysis and concepts
Lecturers Chris Snijders c.c.p.snijders@gmail.com Uwe Matzat u.matzat@tue.nl Rudi Bekkers r.n.a.bekkers@tue.nl Mila Davids m.davids@tue.nl Gerrit Rooks g.rooks@tue.nl
The course: organization • Three courses: 0ZM05 (5 ects) 0EM15 (6 ects) 0A150 (3 ects) • Lectures every week on Wednesdays, hours 7 and 8. Later in the program less lecture time, more "assignment time" (see the course website). • Different courses, so not everybody has to do the same ...
Rough outline for the different courses(see online for the details) + survey completion (so that you experience what a network survey feels like, and we can analyze the data during class and assignments)
Course requirements • 0em15/0zm05: Two (group of 2) assignments + written exam. Grade = 50% assignments + 50% exam. Both assignments and the exam should be at least a 4.0. Final grade should be at least 5.5. For 0a150 it’s the average of the two assignments, where both should be at least 4.0 and the average at least 5.5
Course aim knowledge about concepts in network theory, and being able to apply that knowledge (with an emphasis on innovation and alliances)
The setup in some more detail Network theory and background • Introduction: what are they, why important … • Four basic network arguments • Kinds of network data (collection) • Typical network concepts • Visualization and analysis
It’s about making our 'social space' visible "If we ever get to the point of charting a whole city or a whole nation, we would have … a picture of a vast solar system of intangible structures, powerfully influencing conduct, as gravitation does in space. Such an invisible structure underlies society and has its influence in determining the conduct of society as a whole." Jacob L. Moreno New York Times, April 13, 1933 Making the invisible visible
We live in a connected world “To speak of social life is to speak of the association between people – their associating in work and in play, in love and in war, to trade or to worship, to help or to hinder. It is in the social relations men establish that their interests find expression and their desires become realized.” Peter M. Blau Exchange and Power in Social Life, 1964 How?
Social Networks – a (cheesy) introduction http://www.youtube.com/watch?v=6a_KF7TYKVc
Social network analysis – it's core • An interdisciplinary perspective emphasizing structural relationships as key explanatory concepts and principles: • Structural propertiesof social formations are contexts that shape the perceptions, beliefs, attitudes, and actions of individuals and collectivities • Social influence and collective action may be facilitated and/or constrained by direct and indirect exchanges (transactions) among social actors possessing differential resources (e.g., information) • Actors and transactions/interactions between actors are embedded, i.e. located within actual situational contexts
A B The network perspective Two firms in the same market. Which firm performs better (say, is more innovative): A or B? • This depends on: • Cost effectiveness • Organizational structure • Corporate culture • Flexibility • Supply chain management • …
A B The network perspective Two firms in the same market. Which firm performs better (say, is more innovative): A or B? Note Networks are one way of dealing with “market imperfection” and ... on the structure of the network
Multi-level and interdisciplinary • Network applications appear in diverse substantive fields of mostly social sciences – anthropology, management, political science, public health, sociology (and recently also in economics) • Studies span micro- meso- & macro-levels of analysis: • personal social & health support systems • children’s play groups, high school cliques • employee performance • neighboring behavior, community participation • work teams, voluntary associations, social movements • military combat platoons, terrorist cells • corporate strategic alliances, board interlocks • international relations: trade, aid, war & peace • Internet relations: Twitter, LinkedIn, Facebook
Example: crime research • Example topics • "Cold case" research • forensic psychiatry • (youth) crime • ...
Network analysis: origins Started in 1920s, Jacob L. Moreno pioneered social network analysis for his “psychodrama” therapy. He usedsociomatricesand hand-drawnsociogramsto display children’s likes and dislikes of classmates asdirected graphs (digraphs).
Example: A targeted approach to HIV prevention • Think about similar examples for: • Introduction of new products into target groups • …
Modern computing makes a big difference “Visualizationhas been a key component of social network analyses from the beginning, proliferating into today’s dazzling computer-based multidimensional displays” (Freeman 2001)
Social network software • UCINet – Many things on network analysis Lin Freeman, Steve Borgatti, Martin Everett • MultiNet – Whole Network Analysis + Nodal Characteristics • P*Star – Dyadic Analysis – Stan Wasserman • NodeXL (an Excel plugin) – Marc Smith • Pajek – Network Visualization – Supersedes Krackplot • StocNet – Tom Snijders - collected programs for, e.g., analysis of dynamic networks • … and many others NB Even though computers are fast, really large networks can still be a real problem
A network (or graph) contains a set of actors (or nodes, objects, vertices), and a mapping of relations (or ties, or edges, connections) between the actors Social network basics 1 2 For instance: Actors: persons Relationships: “participates in the same course as” Or: Actors: organizations Relationships: have formed an alliance
Relationships can be directed: Symmetrical by choice: Symmetrical by definition: (usually depicted as) Social network concepts: ties 2 1 For instance: person 1 likes person 2 1 2 Person 1 likes 2, 2 likes 1 1 2 Person 1 is married to 2 1 2
Relationships can carry weights : Actors can have a variety of properties associated with them: Social network concepts: weights 2 1 4 3 Actors: persons Relationships: know each other 3 and 4 know each other better (stronger tie)
There is reciprocity: whenever there is a tie from a to b, there also is a tie from b back to a Actor A is powerful: many connections go through A Social networks: translating arguments 1 2 3
Quantifying matters through network concepts • Actor characteristics: • outdegree • indegree • betweenness • ... (and many more) • Network characteristics • density • segmentation • distribution of outdegrees • ... (and many more)
An example of a modern network:9-11 Hijackers Network SOURCE: Valdis Krebs http://www.orgnet.com/
OECD Trade Flows 1981-1992 Note: practical use of visualization diminishes as networks grow larger SOURCE: Lothar Krempel http://www.mpi-fg-koeln.mpg.de/~lk/netvis.html
… also for business purposes … http://www.youtube.com/watch?v=6SSR2tg5n_U
… or, if you want to create your own FaceBook-like site … http://www.vivalogo.com/vl-resources/open-source-social-networking-software.htm BTW Lots of businesses are willing to do the dirty work for you …
Organizations as networks:org-chart shows formal ties… SOURCE: Brandes, Raab and Wagner (2001) <http://www.inf.uni-konstanz.de/~brandes/publications/brw-envsd-01.pdf>
