complex systems: the intellectual landscapegeza.kzoo.edu/~erdi/compl/nlec1-19.pdftsunamies,...

COMPLEX SYSTEMS: THEINTELLECTUAL LANDSCAPE

Peter [email protected]

Henry R. Luce ProfessorCenter for Complex Systems Studies

Kalamazoo Collegehttp://people.kzoo.edu/ perdi/

andInstitue for Particle and Nuclear Physics, Wigner Research Centre, Hungarian Academy

of Sciences, Budapesthttp://cneuro.rmki.kfki.hu/

– Typeset by FoilTEX – 1

Why complexity science is the science of the 21st century?

I think the next century will be the century of complexity.”Stephen Hawking (Complexity Digest 2001.10 March-05-2001)

Complex world problems

• GLOBAL WARMING: MYTHS and REALITIES

• TSUNAMIES, EARTHQUAKES, WILDFIRES and other NATURAL disasters

• RIOTS, GENOCIDES, TERRORISM and other SOCIAL extreme events

• BIOLOGICAL and SOCIAL EPIDEMICS: PROPAGATION and CONTROL of INFEC-TIOUS DISEASES and IDEAS

• COMPUTATIONAL NEUROLOGY / PSYCHIATRY and COMPLEX SYSTEMSMODELING

• INTERNET and SOCIAL MEDIA: BLESSING or CURSE?

• DEMOCRACY vs AUTHORITARIANISM 2.0.

• FINANCIAl CRISIS, RISK MANAGEMENT


GLOBAL WARMING: MYTHS and REALITIES

’...96.2% of climatologists whoare active in climate research be-lieve that mean global temperatureshave risen compared to pre-1800slevels, and 97.4% believe that hu-man activity is a significant factorin changing mean global tempera-ture... ’ (Doran and Zimmerman,2009)

• The Question of Global Warm-ing

• Examining the Scientific Con-sensus on Climate Change

• Beyond the Ivory Tower: TheScientific Consensus on ClimateChange

• Financial Risks of ClimateChange

.

Figure 1: Atmospheric carbondiox-ide concentration


William Nordhaus: the science, economics

and politics of the central environmental

issue. Climate change is profoundly alter-

ing our world in ways that pose major risks

to human societies and natural systems.

Nobel prize winner (2018) William Nord-

haus provided tools to fight global warming

Washington Post 2018/10/12/

A far cleaner environment,

markedly less political polarization,

and an economy incentivized to

be clean: That’s what our world

would look like had we acted on

Nordhaus’s ideas when he pro-

posed them. That he was ignored

by market-minded conservatives

makes the awarding of the prize

this week especially poignant.

As the IPCC report shows, we now

need to take rapid, massive action

to limit climate change. The things

we’ve tried have helped on the mar-

gins, but it’s time to get serious.

Nordhaus still provides a good map

for what we could do.

.


TSUNAMIES, EARTHQUAKES, WILDFIRES and otherNATURAL disasters

The 20-foot high tsunami hit thePacific coastline of Japan, destroy-ing many lives and much property.A recent study by Mark Ablowitzand Douglas Baldwin, mathemati-cians at the University of Col-orado at Boulder, offers new in-sight into the causes of tsunamisbased on satellite images taken dur-ing the calamity. Tsunamis are se-ries of water waves that displacelarge volumes of water and oftenreach extraordinary heights, endan-gering coastal structures and peo-ple. Large disturbances, such asexplosions, volcanoes, and earth-quakes, are typically the causes ofa tsunami.

.



It is a little too optimistic

Customer ReviewsUselessIt only ”work” while the app is run-ning. Do you think I’ll spend myentire days and nights running thisapp ??? It’s a good idea but Ithought it would be connected to asource providing the measurementdepending of where you are. Likethe earthquake apps for example.



• Indonesia tsunami (2018 De-cember) caused by collapse ofvolcano

• Expert confirmation comes asofficials say country needs newtsunami early warning system

• ”In fact, of the 170 earthquakesensors we have, we only have amaintenance budget for 70 sen-sors”

• Warning system might havesaved lives in Indonesiantsunami


Predicting disasters thankless jobOctober24th, 2012 Six years in jail and an average fine of over a million dollars: that was the punishment given six Italian

scientists Monday for getting their earthquake advice wrong. So what will the expert geologists in Italy say the next time they are asked about the

likelihood of an earthquake? They will refuse to say anything, of course.

More than 5, 000 scientists have signed a letter supporting their colleagues who found themselves standing trial for manslaughter in the medieval

city of L’Aquila, where 309 people died in an earthquake in 2009. But the case is a bit more complex than it first appears.

There were hundreds of small shocks around L’Aquila in the weeks before the big one struck, and the six scientists were sent to the city to assess

the level of danger. They judged the risk as minor, and one, foolishly, said there was ”no danger”. ...



.

Figure 2: Paradise, Calif.,Destroyed By Wildfire

..

Forest fire modeling: prediction and controlhttps://patternandprocess.org/5-3-a-simple-percolation-based-forest-fire-model/


https://patternandprocess.org/5-3-a-simple-percolation-based-forest-fire-model/

VIOLENCE, RIOTS, GENOCIDES, TERRORISM and otherSOCIAL extreme events

• Terrorist strikes have happenedover many decades

• This history creates a richdatabase

• Data analysis shows that theyfollow maths laws

• Using these laws, one can calcu-late the probability of a terroriststrike of specific magnitudes

• These forecasts, when fully de-veloped, can be useful forpreparing responses


BIOLOGICAL and SOCIAL EPIDEMICS: PROPAGATION andCONTROL of INFECTIOUS DISEASES AND IDEAS



Ebola 2014



Control strategies:to decrease infection probabilityto remove and cure infected (and infectious) subpopulation


COMPUTATIONAL NEUROLOGY / PSYCHIATRY andCOMPLEX SYSTEMS MODELING

• Computational Systems Biol-ogy: against the reductionisttyranny

• Hierarchical (multilevel):molecule, cell, tissue, organ,organism, community

• Neural Disorders as DynamicalDiseases

• Biology - Computer Science -Engineering

• Model Integration


INTERNET and SOCIAL MEDIA: BLESSING or CURSE?

What media do you use?

WHY?

https://www.youtube.com/

watch?v=DhQAsW___C0


https://www.youtube.com/watch?v=DhQAsW___C0

https://www.youtube.com/watch?v=DhQAsW___C0

INTERNET and SOCIAL MEDIA: BLESSING or CURSE?

Analysis of Social Media Data


DEMOCRACY vs AUTHORITARIANISM 2.0.

According to the overused quote ofChurchill, “Democracy is the worstform of government, except for allthe others.” The early Americandemocracy was based on the com-bination of hierarchical and networkstructures and proved to be very ef-ficient. While most governmentsoperate on the rule of law, whichprescribes that everybody—yes, ev-erybody, “believe me,” everybody,even the president—is equally sub-ject to law, democratic societies arebased on the key principle of freeand fair elections.


FINANCIAL CRISIS, RISK MANAGEMENT

Market crash


From Complex World Problems to the Theory of Complex Systems andBack

• Critical Thinking: Analysis and Actions

• Dynamics: Understanding Changes

• Thinking with Models

• Bioloigical and Social Dynamics

• Predictability: Scope and Limits

• Complex Organizations: Biological and Social Networks

• Complexity of the Brain

• Computational Social Science


How to characterize simple and complex systems?

• all systems interact with their environ-

ment

• How can we then identify what a sys-

tem is?

• Aren’t we always making an artificial

boundary?

• once a system is identified (the bound-

ary described) then one describes:

– the properties of the system, (how

to characterize the state of the sys-

tem)

– the properties of the universe ex-

cluding the system which affect the

system

– the interactions / relationships be-

tween them.

• it is simply a task of the describer to

identify the way in which the system is

interdependent with the environment.


How to characterize simple and complex systems?

Simple systems

What are simple systems?

• Single cause and single effect (common sense thinking and problemsolving, classical engineer’s and the medical doctor’s fundamental approach)

• A small change in the cause implies a small change in the effects [does notliterally mean that there is a linear relationship between the cause and the effect...

• Predictability example for simple pattern: 01010101... but it means that the system’s behavior will not be surprising, its behavior ispredictable].


Be cautious!!!predictable?!

may happen !!

From regular to volatile dynamics


Complex systems

There is a feedbackfrom the ”effect” to the ”cause”

+ circular causality: in essenceis a sequence of cause and effectwhereby the explanation for a pat-tern leads back to the first causeand either confirms or changes thatfirst cause; Example: A causes Bcauses C that causes or modifies A.

+ logical paradox: a person fromthe island of Crete asserts, ”AllCretans are liars.”We can concludethat if he is telling the truth, thenhe is lying. But if he is lying, thenhe is telling the truth.

+ small change in the cause impliesdramatic effect (”butterfly effect”)

+ emergence


Emergence of complexity

Emergence is:1. What parts of a system do together that they would not do by themselves: collectivebehavior.

HOW collective properties arise from the properties of parts.

HOW behavior at a larger scale of the system arises from the detailed structure,behavior and relationships on a finer scale.

In the extremeHOW MAcroscopic behavior arises from MIcroscopic behavior.

2. What a system does by virtue of its relationship to its Environment that it wouldnot do by itself: e.g. its FUNCTION .

Complex Dynamic Behaviour: CHAOS and related areas


Interaction with the environment

Feedback: is a process wherebysome proportion of the output sig-nal of a system is passed (fed back)to the input.


Feedback everywhere


positive and negative feedback —> nontrivial dynamic behavior

Ecosystem and human social system: has numerous positive and negative feedbackloops.Both kinds of feedback are essential for survival.Negative feedback -> stability; it keeps important parts of the system within the limitsrequired for proper functioning.Positive feedback -> the capacity to change drastically when necessary (economics: ”in-creasing return”; sociology: ”Matthew effect”- the rich get richer and the poor get poorer. . .


The development and growth of all biological systems - from cells and individualorganisms to ecosystems and social systems - is based on the interplay of positive andnegative feedback.

Balance between the forces thatpromote change and the forces thatprovide stability. (There is a MATHbehind SUSTAINABILITY!)


Logical paradoxes. Self-referential systems

This sentence is false.

The next sentence is false.The preceding sentence is true.

Russel’s Barber Paradox:

In a small town, a barber cuts the hair of all people who do not cut their ownhair, and does not cut the hair of people who cut their own hair. Does the barbercut his own hair? Suppose he does cut his own hair. But by the second halfof the first sentence, he does not cut the hair of people who cut their own hair,including the barber himself. Contradiction. Suppose he does not cut his ownhair. Then by the first half of the first sentence he does cut the hair of peoplewho don’t cut their own, including the barber himself. Contradiction.


Strange loops

Douglas Hofstadter: Godel, Escher,Bach: An Eternal Golden Braid.”whenever, by moving upwards (ordownwards) through the levels ofsome hierarchical system, we unex-pectedly find ourselves right backwhere we started”


Strange loops

Maurits Cornelis Escher (1899-1972)


Small changes imply dramatic effects

• Sensitive dependency on initialconditions

• Nonlinear Dynamic Systems

• Chaos, Strange Attractors, Frac-tals

• Deterministic, but irregular

• Limits to Predictability ??

LOOKING INTO THE PAST -PREDICTING THE FUTURE


complex systems: the intellectual landscapegeza.kzoo.edu/~erdi/compl/nlec1-19.pdftsunamies,...

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