complex systems update

scientific

complex systems are composed of many interconnected parts and cannot be tackled analytically, i.e., by using closed-form mathematical expressions. complex systems come from many domains:

• socio-economic
  
• technological
  
• biological

Complex systems are often represented by networks; source.

they are typically characterized by non-linear behavior, display emergence ("the whole is greater than the sum of its parts") and are highly adaptive.

complex systems can be viewed as the current frontier in the understanding of the workings of nature, which started with the analysis of liner systems described by few variables:

(source: s. strogatz; "nonlinear dynamics and chaos"; 2001)

there are arguably two main strands in the study of complex systems:

1. complexity science or complex adaptive systems
   
2. multi-agent systems
   

the former fields find their moder incarnation mostly in the form of complex network theory, where the system's elements are represented by nodes in a graph, and their interactions are defined by the graphs edges. complex networks can have three levels of description:

1. direction of links
2. weights of links
3. variables assigned to nodes

the topology of the network often reflects its function.

multi-agent systems originate from the computational approach of agent-based modeling. agents interact with each other through local rules. often the evolution of these systems can only be known by letting the actual simulation evolve.


(source: wikipedia, complexity map overview)

slowly however, the focus has shifted on merging the two strands. in may 2010 there will be a workshop on "emergent intelligence on networked agents". from the description:

the intention of this workshop is to [bridge] the gap between the two research communities in complex networks and multi-agent systems.

currently, it seems that research on multi-agent systems is still mostly focused on agents themselves, whereas networks of agents have received relatively little attention.

a framework to model these multi-agent systems is provided by the complex networks approach [...]. thus, the underlying network structure of a multi-agent system plays a crucial role in explaining emergent properties. networked agents, on the other hand, may be able to actively change this structure by forming new links or cutting existing ones. consequently, there is not only a strong relation, but a coevolution in the dynamics of agents and their network of interactions.

how the brain works...

fascinated

"the brain creates a version of the universe and projects this like a bubble around us."

"99% of what you see is not what comes in through the eyes, it is what you infer."

"reality emerges out of the fabric of the brain."

"how could we possibly create a reality that we can even understand each other [as every brain has a different fabric]?" although the brain circuitry can change, the pattern of reality that emerges does not.

the first glimpse of simulated neuron activity in a supercomputer: the raw electrical activity creates "ghost like structures"

"the universe [possibly] has evolved the brain to see itself. which may be a first step of becoming aware of itself."

the idiosyncratic borders of knowledge

:-/

we spend billions of dollars trying to understand the origins of the universe, while we still don't understand the conditions for a stable society, a functioning economy, or peace.

Dirk Helbing, July 2009, Science special online collection: Complex Systems and Networks

[..] we have better maps of Mars than [the territory belonging to the US that lies beneath the sea, which is as big as the US itself].

Robert Ballard, December 2008, Exploring the Oceans (TED talk)

good and evil

enlightened
how to get people to do evil:

• mindlessly taking the first small step down the road to evil
  

• dehumanization of others

• de-individuation of self (anonymity)

• diffusion of personal responsibility

• blind obedience to authority

• uncritical conformity to group norms

• passive tolerance of evil (inaction, indifference)

watch philip zimbardo's (the stanford prison experiment guy) ted talk:

the cause of the financial crisis..

unimpressed
how did a housing crisis become a financial crisis, ending up as an economic crisis?

how come highly trained professionals didn't see it coming?

a nice simple summary visualizing all the subprime mortgage, CDO, CDS, leverage, tranching, rating, AAA, default, frozen credit market stuff:


at the barebones level, wired magazine gives insight into the core mechanism in their article Recipe for Disaster: The Formula That Killed Wall Street.

the culprit:

the gaussian copula function

basically a quantity measuring the correlation (preciser: the dependence structure) of two random variables.

"the corporate CDO world relied almost exclusively on this copula-based correlation model."
"everyone was pinning their hopes on house prices continuing to rise."

the idea, published in 2000, quickly became a metric quants ubiquitously used to evaluate risk and a cornerstone of financial engineering allowing simple modeling of vastly complex risks. particularly default risks of CDO tranches. until august 2007...

the ideas:

• tame the nasty nature of real-world dynamical, complex and latent variables by substituting them with a clean and simple number summing up everything
• convey an image of what is happening: correlation is more like a constant than a fluctuating variable and all you need to know and compute
  
• let the method be adopted by investors, banks, rating agencies and regulators
  
• ignore any warning signs (for instance d. sornette in 2006: "this recurrent use [of gaussian copulas] has been ratified by the recommendations of the BIS concerning credit risk modelling. however, there are many indicators suggesting that this [...] approach may be grossly inadequate to account for large credit risks [...]." pg. 138)
  
• let everyone make a lot of money
• let quants forget about the concrete reality behind the math and crank up the models
• let managers, lacking formal math skills, execute transactions worth trillions of dollars based on the models
  
• forget about the underlying magic that makes it all work: a decade of soaring housing prices
• lend money to people without jobs and income
  
• be surprised when everything blows up in your face
  

cartoon from cagle.com

--
update 28th of june 2010:

who cares?

mood: more bewilderment and head-shaking
is the human brain big enough to save one of the most intelligent creatures? greenpeace asks cynically in an add, aiming at banning whaling amongst other ocean related concerns.

when i mention i'm vegetarian in restaurants, a frequent response is to point me in the direction of the fish...


greenpeace campaign

fact i: the ocean is humanities last frontier of ignorance

• 72% of earth's surface covered by sea
• 97% of the ocean is unexplored
• with one yearly NASA budget, the exploration program of NOAA (the National Oceanic and Atmospheric Administration) could be funded for 1600 years
• largest mountain range covering 23% of earth's surface area underwater (visited for the 1st time after the moon in 1973)
• coral reefs still unexplored between 60 and 150 meters
• there are better maps of mars than the 50% of total US territory which lies under the sea
• most of the southern hemisphere's underwater terrain is unexplored (more exploration ships in that region during captain cook's times than today)
• the seabed is harboring countless well preserved archaeological artifacts
• underwater hot springs are basically commercial grade heavy metals deposits
• underwater volcanoes are emitting methane

fact ii: the oceans are teeming with life

• although most of the ocean does not get exposed to photons from the sun, and hence there is no photosynthesis, it is completely erroneous to not expect life
• the antarctic sea is, unexpectedly and only recently discovered, teeming with marine life
• hydrothermal vent systems are islands of life
• bacteria replicating photosynthesis in the dark by chemosynthesis where accidental discovery as no one ever predicted their existence
• resilient bacteria living in ph 11 environments
• 7 new species found per hour of deep reef exploration
• 2000 to 2500 estimated new species in the indo-pacific ocean alone (vs. 5000-6000 known species)
  
• not only new species are still being discovered, but also new behavior and new ecology
• amazing variety of bioluminescent animals
  

fact iii: the seas are being destroyed at breakneck speed

• 90% of all big fish have disappeared in the last 100 years
• 50% of all coral reefs are destroyed
• for 1kg of fish ending up in a market, at least 10kg of bycatch was killed and thrown away
• 1.7% of the blue whale population is remaining
• 10% of the tuna fish population is remaining
• commercial trawlers are forced to access ever deeper seabed due to the depletion of fisheries; this completely destroys potential habitats which are totally unexplored and eradicates possibly unknown species
• throwaway plastic accumulating in the sea (half of the 100 billion pounds of plastic pellets a year are made into throwaway plastic produces of which a large fraction ends up in the sea)
• 100000 albatross chicks in remote habitats dying from stomachs filled with plastic trash
• some ocean water samples contain more plastic than plankton
• plastic debris concentrate pollutants and become "poison pills"
• these are been eaten by many fish at the bottom of the food chain
• gigantic garbage patches in the pacific and atlantic
  

Sylvia Earle's moving (and prizewinning) TED talk:


Robert Ballard: Exploring the ocean's hidden worlds


Captain Charles Moore on the seas of plastic


Richard Pyle: Exploring the reef's Twilight Zone


David Gallo fascinating TED talk:


update 20.04.2010:
Edith Widder: Glowing life in an underwater world


update 05.05.2010:


update 02.06.2010:
Brian Skerry reveals ocean's glory -- and horror


update june 30th 2010:


update july 12 2010:


update july 27 2010:

messages from banksy

mood: respectful
"people who get up early in the morning cause war, death and famine"

"sometimes i feel so sick at the state of the world i can't even finish my second apple pie"

"the greatest crimes in the world are not committed by people breaking the rules but by people following the rules.
it's people who follow orders who drop bombs and massacre villages.
as a precaution to ever committing major acts of evil it is our solemn duty never to do what we're told. this is the only way we can be sure"

"it takes a lot of guts to stand up anonymously in a western democracy and call for things no-one else believes in - like peace and justice and freedom"

"we can't do anything to change the world until capitalism crumbles; in the meantime we should all go shopping to console ourselves"

"people who enjoy waving flags don't deserve to have one"

"a lot of people never use their initiative because no-one told them to"


banksy is a british graffiti artist. he has reached international fame notably for stunts like:

• hanging a picture he painted (depicting mona lisa with a yellow smiley face) in the louvre
• or painting images on the israeli west bank wall showing, for instance, a girl being blown away by holding on to flying balloons
• or spraying "this is not a photo opportunity" on certain well-known photograph spots around the world
  
• or painting official looking signs on white walls reading "this wall is a designated graffiti area" and documenting the progress of tags and graffitis being created there by other street artists.

hollywood celebrities have purchased his art and one piece was auctioned for over half a million usd in 2007. he responded to a sotheby’s sale of his work by posting a painting on his website featuring people bidding for a picture, with the caption "i can't believe you morons actually buy this shit."

his view of life is anti-authoritarian, anti-war, anti-consumerist and anti-establishment, using very strong imagery for his pictures. his messages are often ironic, cynical, very to the point and critical comments on the current zeitgeist.

his true identity is unknown...

sources: webpage, wikipedia, wall and piece.