CS 346U!

Exploring Complexity in Science and Technology !

Instructor: Melanie Mitchell!

Textbook: !"M. Mitchell, Complexity: A Guided Tour !

(Oxford University Press)!

•  Note: All slides for a lecture will be available on the class webpage before each lecture:!

http://www.cs.pdx.edu/~mm/ExploringComplexityFall2011!

What are Complex Systems?!

Large networks of simple interacting elements, "

which, following simple rules, produce emergent, "

collective, complex behavior."

What are Complex Systems?!

Insect colonies!

video1!

video2!

Brains!

video!

Immune system!video (+47sec.)

Economies!

Schweitzer  et  al.,  Science,  325,  422-­‐425,  2009  h7p://www.sciencemag.org/cgi/content/full/325/5939/422  

Food webs

Genetic Regulatory Networks

http://www.ibiblio.org/hhalpin/homepage/presentations/de2007/webearth.jpg

World-Wide Web

Social Networks

http://www.facebook.com/notes/facebook-engineering/visualizing-friendships/469716398919

h7p://cogniAveciAes.com/  

h7p://www.nature.com/nature/journal/v467/n7318/full/467912a.html  

Cities

Do these systems have anything in common? "

Central question for the !sciences of complexity"

!How do large networks with !

! !— simple components!! !— limited communication among components !! !— no central control!! !— simple rules of operation!

give rise to complex (“adaptive”, “living”, “intelligent”) behavior, involving!

! !— information processing and computation!! !— complex pattern dynamics!! !— evolution and learning?!

Core disciplines of !the science of complexity"

Dynamics: The study of continually changing structure

and behavior of systems"

Information: The study of representation, symbols, and

communication"

Computation: The study of how systems process

information and act on the results"

Evolution: The study of how systems adapt to constantly

changing environments"

Goals of the Science of Complexity"

•  Cross-disciplinary insights into complex systems"

•  General theory"

Methodologies

Methodologies

€

∇⋅ E = 4πρ

∇ × E = −1c∂B∂t

∇⋅ B = 0

∇ × B =4πcJ +

1c∂E∂t

Methodologies

Methodologies

Course Details"

•  Course web page:"http://www.cs.pdx.edu/~mm/ExploringComplexityFall2011/!

•  Textbook: Mitchell, Complexity: A Guided Tour!

•  My office hours: T, Th 3-4pm!

Netlogo"

•  We will use Netlogo to illustrate / experiment with complex systems ideas. Part of first assignment is to download Netlogo. !

http://ccl.northwestern.edu/netlogo/!

•  Bring laptop to class if possible. !

Assignments " ""

•  Weekly homework assignments: reading, writing, Netlogo!

•  Term project: "–  Build simulation in Netlogo!

–  Experiments using simulation!

–  Read 2 (or more) published paper related to topic of simulation!

–  Write term paper on simulation, results, related papers !•  10-20 pages, double-spaced, including figures and references!

We will spend time in class learning Netlogo and formulating/working on final projects.!

Grading " ""

•  Homework: 60%!

•  Term project and writeup: 40%!

Class Rules"

•  Turn off cell phone!

•  During class, laptops are for taking notes, not for reading mail, chatting, web surfing, etc. !

•  While you’re here, make it worth your while. Pay attention. !

•  In return, class will be interesting enough to hold your attention! (I hope…) !

26  

Introduction to Netlogo"

“Pre-homework” assignment:"

–  Download Netlogo and Users Manual!(You don’t have to print the manual)!

–  Try out some of the models in the Models Library!

–  Try to modify programs we wrote today (file will be on the class web page)!

You don’t need to turn in anything for this. !

!Homework 1 assignment will be handed out on Wednesday. !