Course Overview
and Introduction
Networked Life
CSE 112
Spring 2004
Prof. Michael Kearns
What do the following questions…
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How does Google find what you want?
How do tolerant populations become segregated?
How did Hush Puppies make a comeback?
How many friends between you and Kevin Bacon?
How should you split $10 with a stranger?
What can the Internet learn from Paris subway?
How is file downloading like a competition?
…have in 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
• Structure, asymmetry and heterogeneity
• Details of interaction matter greatly
• The metaphor of viral spread
• Qualitative and quantitative; can be very subtle
• A revolution of
– measurement
– theory
– breadth of vision
Who’s Doing All This?
• Computer Scientists
– Understand and design complex, distributed networks
– View “competitive” decentralized systems as economies
• Social Scientists, 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 Vision and Mission
• A network-centric examination of a wide range of social,
technological, financial and political systems
• Examined via the tools and metaphors of:
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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.
– extensive web visualizations and demos
• A mix of humanities and science
Course Outline
The Networked Nature of Society
(~1 lecture)
• Networks as a collection of pairwise relations
• Examples of familiar and important networks
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Social networks
Content networks
Technological networks
Economic networks
• The distinction between structure and dynamics
• Network formation
A network-centric overview of modern society.
Contagion, Tipping and Networks
(~2 lectures)
• Epidemic as metaphor
• The three laws of Gladwell:
– Law of the Few (connectors in a network)
– Stickiness (power of the message)
– Power of Context
• The importance of psychology
• Perceptions of others; interdependence and tipping
• Paul Revere, Sesame Street, Broken Windows, the Appeal
of Smoking, and Suicide Epidemics
Informal case studies from social behavior and pop culture.
Introduction to Graph Theory
(~1 lecture)
• Networks of vertices and edges
• Graph properties:
– cliques, independent sets, connected components,
cuts, spanning trees,…
– social interpretations and significance
• Special graphs:
– bipartite, planar, weighted, directed, regular,…
• Computational issues at a high level
Beginning to quantify our ideas about networks.
Social Network Theory
(~4 lectures)
• Metrics of social importance in a network:
– degrees, closeness, between-ness,…
• Local and long-distance connections
• SNT “universals”
– small diameter
– clustering
– heavy-tailed distributions
• Network formation
– random graph models
– preferential attachment
– affiliation networks
• Examples from society, technology and fantasy
A statistical application of graph theory to human organization.
The Web as Network
(~2 lectures)
• Web structure and components
• Web communities
• Web search:
– hubs and authorities
– the PageRank algorithm
– redundancy and co-training
The algorithmic implications of network structure.
Emergence of Global from Local
(~2 lectures)
• Context, motivation and influence
• The madness of crowds:
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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
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Nash
correlated
cooperative
market
bargaining
• Multi-player games
• Social choice theory
A powerful mathematical model of what happens
over links in competitive and cooperative settings.
Social Games on Networks:
Interdependent Security
and Market Economies
(~2 lectures)
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Tragedies of the commons
Catastrophic events: you can only die once
Fire detectors, airline security, Arthur Anderson,…
Buying and selling on a network
Preferential attachment, price variation, and the
distribution of wealth
Blending network, behavior and dynamics.
Behavioral Economics
(~2 lectures)
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What’s broken with game theory?
How should you split 10 dollars?
The return of context
Guilt and envy: fixing the theory
Controlled social psychology experiments
examining how “rational” we really are(n’t).
Evolutionary Game Theory
(~2 lectures)
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Fitness and evolutionary dynamics
Mimicking and replicating vs. optimizing
Evolutionary stable strategies
The evolution of cooperation
Replication and viral spread
From economics to biology, and back again
Internet Basics
(~2 lectures)
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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)
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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)
• Market microstructure
– limit and market orders
– order books and electronic crossing networks
– network and connectivity issues
• Quantitative trading
– VWAP trading, market making
– limit order power laws
• Herd behavior and power law returns
• Economic theory and financial markets
• Behavioral economics and finance
A study of the network that runs the world.
Course Mechanics
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Will make heavy use of course web page:
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No technical prerequisites
Lectures:
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Readings: mixture of general audience writings and articles
from the literature
Three required texts:
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Problem sets (approximately 6); about 25% of grade
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Midterm; about 25% of grade
Final exam; about 50% of grade
Recitations: optional but highly recommended
– www.cis.upenn.edu/~mkearns/teaching/NetworkedLife
– You will need good Internet access!
– slides provided; emphasis on concepts
– frequent demos, visualizations, and in-class experiments
– “The Tipping Point”, Gladwell
– “Six Degrees”, Watts
– “Micromotives and Macrobehavior”, Schelling
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computer/web exercises
short essays
quantitative problems
collaboration is not permitted
– Tuesday 5-6 in Towne 311
– Wednesday 5-6 in Towne 313
First Assignment
• Due next lecture (Th 1/15)
• Simple background questionnaire
• Last-names exercise