Introduction Course and Overview
Networked Life CSE 112 Spring 2006 Prof. Michael Kearns
A purely technological network? Points are physical machines Links are physical wires Interaction is electronic What more is there to say?
Internet, Router Level
Points: power stations Operated by companies Connections embody business relationships Food for thought:
2003 Northeast blackout
North American Power Grid
Points are still machines but are associated with people Links are still physical but may depend on preferences Interaction: content exchange Food for thought: free riding
Gnutella Peers
Points: sovereign nations Links: exchange volume A purely virtual network
Foreign Exchange
Purely biological network Links are physical Interaction is electrical Food for thought:
Do neurons cooperate or compete?
The Human Brain
The Premise of Networked Life
It makes sense to study these diverse networks together. The Commonalities:
Formation (distributed, bottom-up, organic,) Structure (individuals, groups, overall connectivity, robustness) Decentralization (control, administration, protection,) Strategic Behavior (economic, free riding, Tragedies of the Common)
An Emerging Science:
Examining apparent similarities between many human and technological systems & organizations Importance of network effects in such systems
How things are connected matters greatly Details of interaction matter greatly The metaphor of viral spread Dynamics of economic and strategic interaction
Qualitative and quantitative; can be very subtle A revolution of measurement, theory, and breadth of vision
Whos Doing All This?
Computer Scientists
Understand and design complex, distributed networks View competitive decentralized systems as economies
Social Scientists, Behavioral Psychologists, Economists
Understand human behavior in simple settings Revised views of economic rationality in humans Theories and measurement of social networks
Physicists and Mathematicians
Interest and methods in complex systems Theories of macroscopic behavior (phase transitions)
All parties are interacting and collaborating
Course Mission
A network-centric examination of a wide range of social, technological, biological, financial and political systems Examined via the tools and metaphors of:
computer science economics psychology and sociology mathematics physics
Emphasize the common themes Develop a new way of examining the world
A Communal Experiment
No similar undergraduate course No formal technical prerequisites
greatly aided by recent books publications in Science, Nature, etc. preliminary class demographics:
~37% freshmen/sophomore ~52% College/Wharton
Extensive web visualizations and demos Extensive participatory in-class and out-of-class social experiments Exercises in data analysis Note: Networked Life is now approved to fulfill the Colleges Quantitative Data Analysis Requirement Also counts as an SEAS engineering elective course
Course Outline
The Networked Nature of Society
(~2 lectures)
Networks as a collection of pairwise relations Examples of (un)familiar and important networks
social networks content networks technological networks biological networks economic networks
The distinction between structure and dynamics
A network-centric overview of modern society.
Contagion, Tipping and Networks
(~2 lectures)
Epidemic as metaphor The three laws of Gladwell:
The importance of psychology Perceptions of others Interdependence and tipping Paul Revere, Sesame Street, Broken Windows, the Appeal of Smoking, and Suicide Epidemics
Law of the Few (connectors in a network) Stickiness (power of the message) Power of Context
Informal case studies from social behavior and pop culture.
Introduction to Graph Theory
(~1 lecture)
Networks of vertices and edges Graph properties:
Special graphs:
cliques, independent sets, connected components, cuts, spanning trees, social interpretations and significance bipartite, planar, weighted, directed, regular,
Computational issues at a high level
Beginning to quantify our ideas about networks.
Social Network Theory
(~3 lectures)
Metrics of social in importance a network: Local and long-distance connections SNT universals
small diameter clustering heavy-tailed distributions random graph models preferential attachment affiliation networks degree, closeness, between-ness, clustering
Models of network formation
Examples from society, technology and fantasy
A statistical application of graph theory to human organization.
The Web as Network
(~2 lectures) Empirical web structure and components Web and blog communities Web search: The Main Streets and dark alleys of the web
hubs and authorities the PageRank algorithm
The algorithmic implications of network structure.
Towards Rationality: Emergence of Global from Local
(~1 lecture)
Beyond the dynamics of transmission Context, motivation and influence The madness/wisdom of crowds:
thresholds and cascades mathematical models of tipping the market for lemons private preferences and global segregation
Begin to connect to classical issues of human and societal behavior.
An Introduction to Game Theory
(~2 lectures) Models of economic and strategic interaction Notions of equilibrium Multi-player games Evolutionary game theory Network effects Social choice theory
mimicking vs. optimizing
Nash, correlated, cooperative, market, bargaining
Powerful mathematical models of what happens over links in competitive and cooperative settings.
Interdependent Security and Networks
(~1 lecture)
Security investment and Tragedies of the Commons Catastrophic events: you can only die once Fire detectors, airline security, Arthur Anderson,
Blending network, behavior and dynamics.
Network Economics
(~2 lectures) Buying and selling on a network Modeling constraints on trading partners Local imbalances of supply and demand Preferential attachment, price variation, and the distribution of wealth
The effects of network structure on economic outcomes.
Behavioral Economics
(~1 lectures)
Whats broken with economics and game theory? How should you split 20 dollars? Beauty contests and ultimatums Cultural and sociological effects The return of context Guilt, envy and altruism: improving the theory
Controlled social psychology experiments examining how rational we really are(nt).
Internet Basics
(~1 lecture) IP addresses Routers Domain Name Servers ISPs Congestion control, load balancing The Web and URLs Security issues, network vulnerability
Under the hood of the quintessential modern technological network.
Internet Economics
(~2 lectures)
Selfish routing The Price of Anarchy Peer-to-peer as competitive economy Paris Metro Pricing for QoS Economic views of network security
The collision of network, economics, algorithms, content, and society.
Modern Financial Markets
(~2 lectures) Stock market networks Market microstructure
correlation of returns limit and market orders order books and electronic crossing networks network, connectivity and data issues VWAP trading, market making limit order power laws
Quantitative trading
Herd behavior in trading Economic theory and financial markets Behavioral economics and finance Impacts of the Internet on financial markets
A study of the network that runs the world.
Course Mechanics
Will make heavy use of course web page:
No technical prerequisites!!! Lectures:
www.cis.upenn.edu/~mkearns/teaching/NetworkedLife You will need good Internet access!
No recitations Readings: mixture of general audience writings and articles from the scientific literature Three required texts:
The Tipping Point, Gladwell Six Degrees, Watts Micromotives and Macrobehavior, Schelling
slides provided; emphasis on concepts frequent demos, visualizations, and in-class experiments please be on time to lectures! (12PM)
Assignments (~1/4 of grade)
Participatory social experiments (~1/4 of grade) Midterm (~1/4 of grade) Final exam (~1/4 of grade)
behavioral economics experiments analysis of experimental results
data analysis: network construction project computer/web exercises, short essays, quantitative problems collaboration is not permitted
First Assignment
Due next lecture (Th 1/12)
Simple background questionnaire Last-names exercise