Embed Size (px)
Citation preview
EME Taster October 2007-- 1Department of Computer Science
EME: Emergence Module
Susan Stepney
Fiona Polack
EME Taster October 2006 -- 2Department of Computer Science
What is an emergent system?
• Many simple elements, no central control
• Overall behaviour that is not an obvious consequence of behaviour of elements– Construction by insects
– Crowd or flock behaviour by people, birds, insects
– Plants grown using simple growth algorithms
– Animals developed from simple cells
EME Taster October 2006 -- 3Department of Computer Science
Why study emergent systems?
• Emergent systems cannot be understood by direct extension of conventional systems ideas
• An emergent system is a system of systems– Emergent properties at system level
– Components at system level*
• Emergence requires a change in scale– Small systems combine to larger-scale effect
* This will not make sense if you are colour-blind or reading in b/w!
EME Taster October 2006 -- 4Department of Computer Science
How can an emergent system be engineered?
• Through studying lots of emergent systems– We’ll cover various sorts in EME
• By considering levels and the environment– Polack and Stepney work on architectural aspects
of emergent system development
• Through simulation and real-world observation– What needs to be modelled to faithfully simulate
emergence?
• Paying attention to dependability assurance…
EME Taster October 2006 -- 5Department of Computer Science
What will we look at?
L-systemsMeasures and uses of complexity
Cellular Automata & variants
Information theoretic views of emergence and self-organisation
Some definitions of emergence
Engineering emergent systems
Examples of emergence in natural systems
Nano-construction
EME Taster October 2006 -- 6Department of Computer Science
CA: demonstrate complex behaviour from simple rules
• CAs
2 1 0 0 0
0 1 0 2 1
0 0 1 2 1
0 0 2 3 2
2 0 1 3 2
Time 1Time 20 3 0 0 1
0 1 0 0 2
0 0 3 2 1
0 1 2 3 2
1 0 0 3 1
1 0 2
0 1 2
0 2 3
3
0 0 0
0 0 0
0 0 0
0 ...TransitionTable rules
...
• Game Of Life CAshttp://www.math.com/students/wonders/life/life.html
• Langton’s self-replicating loops
http://necsi.org/postdocs/sayama/sdsr/java/
EME Taster October 2006 -- 7Department of Computer Science
What will we look at?
• Demonstrations that complex behaviour emerges from multiple instances of simple systems:
• L-systems– Aristid Lindenmeyer & Przemyslaw Prusinkiewicz– biological metaphor: plant branching growth
• eg. a bud becomes a twig, a twig gains buds, …
EME Taster October 2006 -- 8Department of Computer Science
What will we look at?
• Demonstrations that complex behaviour emerges from multiple instances of simple systems:
• L-systems– Aristid Lindenmeyer & Przemyslaw Prusinkiewicz– biological metaphor: plant branching growth
• eg. a bud becomes a twig, a twig gains buds, …
– a production replaces a parent module with a child module
pn: symbol rewrite_string
“bud” “twig” p1 : B T
“twig” “twig” “bud” “bud” p2 : T TBB
EME Taster October 2006 -- 9Department of Computer Science
What will we look at?
• Demonstrations that complex behaviour emerges from multiple instances of simple systems:
• L-systems– Aristid Lindenmeyer & Przemyslaw Prusinkiewicz– biological metaphor: plant branching growth
• eg. a bud becomes a twig, a twig gains buds, …
[Prusinkiewicz & Lindenmeyer, fig 1.24a, c, d, 1.10, 1.24f, 1.8]
EME Taster October 2006 -- 10Department of Computer Science
What will we look at?
• Demonstrations that complex behaviour emerges from multiple instances of simple systems
• … and various other artificial complex systems
EME Taster October 2006 -- 11Department of Computer Science
What will we look at?
• Demonstrations that complex behaviour emerges from multiple instances of simple systems:
• Nanotechnology– “molecular” nanotech
• little things that make big things
– Nanobot constructors and replicatorsDesign for a fine-motion controller for molecular assembly - 3000 atoms, <1nmhttp://www.imm.org/
EME Taster October 2006 -- 12Department of Computer Science
Engineering
• Not much work has been done on engineering– Most artificial emergent systems are hacked
• Conway’s Game of Life CA was discovered by playing with patterns on a GO board
• Proposals for real-world nano-scale assemblers and disassemblers make engineering urgent
• We’ll look at – Identifying and measuring emergence– Layers in emergent systems– Towards assurance-directed development
frameworks
