Presentation on theme: "New Mexico Computer Science for All"— Presentation transcript:
1New Mexico Computer Science for All Exploring Complex Systems through Computer ModelsBy Irene LeeDecember 27, 2012Hi, my name is Irene Lee. I am the principal investigator on NM CSforAll, In this video I’m going to introduce the program.
2OutlineIntroduction to complex systems What are they Why do we study them How do we study them
3What is a complex system? Complex (adj.)difficult-to-understand or difficult to predictSystem (noun)A group of interacting, interrelated, or interdependent parts forming a whole.A “Complex System”is collections of simple units or agents interacting in a system. Large- scale behaviors of the system are difficult to understand or difficult to predict and may change, evolve, or adapt.There’s a joke here… a complex system is greater than the sum of its parts.As we will see, a complex system, like its definition, is greater than the sum of its parts.
7A classic example flocking - Craig Reynolds Separation: steer to avoid crowding local flockmatesAlignment: steer towards the average heading of local flockmatesCohesion: steer to move toward the average position of local flockmates
11A classic example Mound building in StarLogo TNG
12Characteristics of Complex Adaptive Systems Non-linear The sum of the parts is not equal to the whole.
13Non-linear means: f(a+b) f(a) + f(b) In MathematicsNon-linear means: f(a+b) f(a) + f(b)Ex.) the exponential function is non-linear.f(2 + 3) f(2) + f(3)f(5) f(2) + f(3)*Non-linear systems are systems that cannot be mathematically described as the sum of their components.
14Characteristics of Complex Adaptive Systems Self-organization The system organizes itself.
15A classic example Schelling Segregation Model Developed by Thomas C. Schelling(Micromotives and Macrobehavior, 1978).
174 Characteristics of Complex Adaptive Systems 1. Leaderless there is no leader (boids)2. Emergent patterns develop from the simple interactions of agents. (termites)3. Non-linear The sum of the parts does not equal the whole.4. Self-organization The system organizes itself
18Why is it important to learn about complex systems and approaches to understanding complex systems?
19Many of the daunting problems of the 21st Century can be studied as complex systems problems. Climate change Loss of biodiversity Pollution Civil violence Spread of disease Emergency Egress Traffic jams Forest fire
21Epidemics NATURE|Vol 460|6 August 2009 Science in the 21st Century Computer models are used by scientists to understand complex systems and possibly prevent (or study interventions for) daunting problems. Such as epidemics.Josh Epstein in a recent issue of Nature states: “As the world braces for an autumn wave of swine flu (H1N1), the relatively newtechnique of agent-based computational modelling is playing a central part in mapping the disease’s possible spread, and designing policies for its mitigation.… Classical epidemic modelling, which began in the 1920s, was built on differential equations. These models assume that the population is perfectly mixed, with people moving from the susceptible pool, to the infected one, to the recovered (or dead) one.Within these pools, everyone is identical, and no one adapts their behaviour. But such models are ill-suited to capturing complex social networks and the direct contacts between individuals, who adapt their behaviours — perhaps irrationally — based on disease prevalence.Agent-based models (ABMs) embrace this complexity. ABMs are artificial societies: every single person (or ‘agent’) is represented as a distinct software individual., “Deputy LANL director, MacBranch, said models were useful to gain an “intuition” about large complex systemsNATURE|Vol 460|6 August 2009
22Networks upload.wikimedia.org/.../Internet_map_4096.png Visualization of the various routes through a portion of the InternetThe internet,Non-linear growthAdaptiveLocal interactions / global structureFeedback, the more get more, distribution of a few very big sites and lots of smaller sites,Self-organizedleaderlessupload.wikimedia.org/.../Internet_map_4096.png