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1 Introduction to Complex Systems: How to think like nature Russ Abbott Sr. Engr. Spec. Rotn to CCAE 310-336-1398  1998-2007. The.

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Presentation on theme: "1 Introduction to Complex Systems: How to think like nature Russ Abbott Sr. Engr. Spec. Rotn to CCAE 310-336-1398  1998-2007. The."— Presentation transcript:

1 1 Introduction to Complex Systems: How to think like nature Russ Abbott Sr. Engr. Spec. Rotn to CCAE 310-336-1398 Russ.Abbott@Aero.org  1998-2007. The Aerospace Corporation. All Rights Reserved. Evolution: how nature thinks

2 2 Peppered moths: evolution in action The (very simple) model: at each time tick –A moth’s probability of survival—not being eaten by predators (not shown)— depends on: How close its color (1-9) is to the background color (0-8). The “Selection” slider, which controls the impact of the environment. -The higher the slider, the more important the environment. –Moths both reproduce and die (of old age). During reproduction, they may mutate—have offspring of a different color. Originally, the vast majority of peppered moths in Manchester, England had light coloration—which camouflaged them from predators since they blended into the light-colored trees. With the industrial revolution: –Pollution blackened the trees. –Light-colored moths died off. –Dark-colored moths flourished. With improved environmental standards, light-colored peppered moths have again become common.

3 3 Try it out File > Models Library > Biology > Evolution > Peppered Moths Click Open

4 4 The nature of evolution Moth (and their colors) are rivals, not adversaries. –It’s more like a race than a boxing match. They are rivals with respect to their ability –to survive and acquire resources from the environment. Moth coloring confers survival value (fitness)—which depends on the environment. Hence Darwin’s “natural selection,” i.e., environmental selection. The environment selects the winners. There may be multiple “winners.” All one needs is a niche, not domination. Nature is not “red in tooth and claw.” –The moths and their colors don’t compete with each other directly. There are no moth-on-moth battles. Nor do the dark moths attempt to convince the light moths that it’s better to be dark — or vice versa. –Coke and Pepsi are rivals for consumer dollars, not adversaries. They do not attempt to kill each other’s CEOs or to sabotage each other’s delivery trucks. Moth (and their colors) are rivals, not adversaries. –It’s more like a race than a boxing match. They are rivals with respect to their ability –to survive and acquire resources from the environment. Moth coloring confers survival value (fitness)—which depends on the environment. Hence Darwin’s “natural selection,” i.e., environmental selection. The environment selects the winners. There may be multiple “winners.” All one needs is a niche, not domination. Nature is not “red in tooth and claw.” –The moths and their colors don’t compete with each other directly. There are no moth-on-moth battles. Nor do the dark moths attempt to convince the light moths that it’s better to be dark — or vice versa. –Coke and Pepsi are rivals for consumer dollars, not adversaries. They do not attempt to kill each other’s CEOs or to sabotage each other’s delivery trucks.

5 5 The nature of evolution Biological evolution takes place among dynamic entities. Dynamic entities are “far from equilibrium.” That means they need energy from the environment to persist. Evolution is fundamentally about energy. The simple view is: more energy, the more successful in reproduction. It’s not a competition, but it is a necessity. More successful groups use more energy, possibly crowding out others. But it’s possible to have a stable ecosystem.

6 6 Application to engineering problems: The Traveling Salesman Problem (TSP) Connect the cities with a path that: Starts and ends at the same city. Includes all cities. Includes no city twice. In this case the problem is easy to solve by inspection. In general, it’s computationally explosive since there are (n-1)! possible tours. B B A A D D E E C C 20 13 12 14 12 7 9 4 24 The obvious tour will include the sequence: ACED-54 (or its reverse). The question is where to put B: ABCED- 55, ACBED-57, or ACEBD-56?

7 7 An exchange (or reverse or mutation) solves this problem in one step. ACBED-57 → ABCED-55 Genetic algorithm approach Create a population of random tours. AEBCD-59, ACBED-57, ADCBE-59, ACDEB-71, … In this case there are only 4! = 24 possible tours. Could examine them all. Usually that’s not possible. Repeat until good enough or no improvement. But beware local optima. Select one or two tours as parents. −Ensure that better tours are more likely to be selected. Generate offspring using genetic operators to replace poorer elements. −Exchange two cities: ACDEB-71 → ACBED-57 −Reverse a subtour: ACBED-57 → AEBCD-59 −(Re)combine two tours: AEBCD-59 & ACBED-57 → AEDCB-71. Possibly mutate the result: ADCBE-59 → ACBDE-70 B B A A D D E E C C 20 13 12 14 12 7 9 4 24 Why not 5!

8 8 Try it out: TSP.jar After starting a run, double click in the display area to add a city or on a city to remove it. –New cities are added to the tour next to their nearest neighbor. Stop and restart for new random cities. –The number of new cities will be the same as the number of old cities. The differences between the current best and its predecessor are shown by link color. –New links are shown in green. –Removed links are in dashed magenta. No “geographical” heuristics are used. Just the structural ones shown on the previous slide.

9 9 The evolutionary process There is a population of elements. The elements are capable of making copies of themselves –perhaps with variants (mutations) and –perhaps by combining with other elements. The environment affects the likelihood of an element surviving and reproducing. This results in “evolution by natural (i.e., environmental) selection.” –Darwin likened it to breeding. The environment plays the rules of the breeder.

10 10 Evolution differs from most science The process described on the preceding page is tautologically true. –Darwin didn’t know about DNA. One doesn’t study evolution by taking something apart and seeing how it works. –There is no reductive explanation for it. There are no underlying mechanisms from which evolution can be derived or upon which it depends. –In that sense it is like a Game of Life Turing Machine. Evolution is an epiphenomenally emergent property of any level of abstraction that satisfies the conditions on the preceding slide. Those conditions can be implemented in many different ways.

11 11 Genetic algorithms: parameter setting/tuning The number of variables is constant. –Both the TSP and the peppered moths examples illustrate genetic algorithms. Peppered moths: one parameter (color) to set. TSP: N variables. As a parameter setting problem think of each tour as consisting of N variables, each of which may contain any city number. The additional constraint is that no city may repeat. Often there are hundreds of variables (or more) or the search space is large and difficult to search for some other reason. There is no algorithmic way to find values that optimize (maximize/minimize) an objective function. Terrile et. al. (JPL), “Evolutionary Computation applied to the Tuning of MEMS gyroscopes,” GECCO, 2005. Abstract: We propose a tuning method for MEMS gyroscopes based on evolutionary computation to efficiently increase the sensitivity of MEMS gyroscopes through tuning and, furthermore, to find the optimally tuned configuration for this state of increased sensitivity. The tuning method was tested for the second generation JPL/Boeing Post-resonator MEMS gyroscope using the measurement of the frequency response of the MEMS device in open-loop operation.

12 12 Genetic Programming: design and analysis The number of variables (and the structure of the possible solution) is not fixed. Originally attempted (not very successfully) to be applied to generating computer programs. But applied successfully to other design and analysis problems. –Circuit design –Lens design Bongard and Lipson (Cornel), “Automated reverse engineering of nonlinear dynamical systems,” PNAS, 2007. Abstract: Complex nonlinear dynamics arise in many fields of science and engineering, but uncovering the underlying differential equations directly from observations poses a challenging task. The ability to symbolically model complex networked systems is key to understanding them, an open problem in many disciplines. Here we introduce for the first time a method that can automatically generate symbolic equations for a nonlinear coupled dynamical system directly from time series data. This method is applicable to any system that can be described using sets of ordinary nonlinear differential equations, and assumes that the (possibly noisy) time series of all variables are observable. … “Symbolic regression”

13 13 The Human-competitive awards: “Humies” Each year at the Genetic and Evolutionary Computing Conference (GECCO), prizes are awarded to systems that perform at human-competitive levels—including the previous two slides. –See http://www.genetic-programming.org/hc2005/main.html An automatically created result is considered “human-competitive” if it satisfies at least one of the eight criteria below. A.The result was patented as an invention in the past, is an improvement over a patented invention, or would qualify today as a patentable new invention. B.The result is equal to or better than a result that was accepted as a new scientific result at the time when it was published in a peer-reviewed scientific journal. C.The result is equal to or better than a result that was placed into a database or archive of results maintained by an internationally recognized panel of scientific experts. D.The result is publishable in its own right as a new scientific result — independent of the fact that the result was mechanically created. E.The result is equal to or better than the most recent human-created solution to a long-standing problem for which there has been a succession of increasingly better human-created solutions. F.The result is equal to or better than a result that was considered an achievement in its field at the time it was first discovered. G.The result solves a problem of indisputable difficulty in its field. H.The result holds its own or wins a regulated competition involving human contestants (in the form of either live human players or human-written computer programs).

14 14 Tom Lang and Laura Speckman: Genetic Algorithm for Constellation Optimization (GACO) Finds optimal constellation orbits using a genetic algorithm under multiple design constraints and with multiple sensor types. For low number of sats, GA arrangement is significantly better than Walker

15 15 Evolution and Innovation Innovation is always the result of an evolutionary process. Randomly generate new variants—by combining and modifying existing ones. Select the good ones. (Daniel Dennett, Darwin's Dangerous Idea) Requires mechanisms: For creating stable and persistent design instances so that they can serve as the basis for new possibilities. For combining and modifying designs. For selecting and establishing the better ones.

16 16 Designs in various environments Recorded asCreated by How instantiated Established InternetSoftware Programmers who know the techniques Self- instantiating By users Scientific knowledge A publication Scientists who know the literature The publication is the instantiation By peer review Market economy Trade secrets Product developers who know the tricks Entrepreneurial manufacturing Consumers Biological evolution DNAReproduction Whether it finds a niche Entities: nature’s memes An implicit design Fortunate combination Implementation of a level of abstraction Whether it finds a niche All bottom-up

17 17 How does this apply to organizations? To ensure innovation: Sounds simple doesn’t it? Creation and trial Encourage the prolific generation and trial of new ideas. Establishing successful variants Allow new ideas to flourish or wither based on how well they do.

18 18 Initial funding Prospect of failure ApprovalsEstablishment Biological evolution Capitalism in the small. Nature always experiments. Most are failures, which means death. (But no choice given.) None. Bottom-up resource allocation defines success. Entrepreneur Little needed for an Internet experiment. Perhaps some embarrassment, time, money; not much more. Few. Entrepreneur wants rewards. Bottom-up resource allocation. Bureaucracy Proposals, competition, forms, etc. Who wants a failure in his/her personnel file— when “mission success” is the corporate motto? Far too many. Managers have other priorities. Top-down resource allocation. New ideas aren’t the problem. Trying them out Innovation in various environments Getting good ideas established

19 19 Innovative environments The Internet The inspiration for net-centricity and the GIG Goal: to bring the creativity of the internet to the DoD What do innovative environments have in common? What do innovative environments have in common? Other innovative environments The scientific and technological research process The market economy Biological evolution

20 20 Innovative environments Innovation is always the result of an evolutionary process. Randomly generate new variants—by combining and modifying existing ones. Select the good ones. (Daniel Dennett, Darwin's Dangerous Idea) Requires mechanisms: For creating stable and persistent design representations so that they can serve as the basis for new possibilities. For combining and modifying designs. For selecting and establishing better ones.

21 21 Designs in various environments Recorded asCreated by How instantiated Established InternetSoftware Programmers who know the techniques Self-instantiatingBy users Scientific knowledge Publications Scientists who know the literature The publication is the instantiation By peer review Market economy Trade secrets Product developers who know the tricks Entrepreneurial manufacturing By consumers Biological evolution DNA Combination and mutation Reproduction Whether it finds a niche Entities: nature’s memes Implicit designs Construction, combination and mutation Implementation of a level of abstraction Whether it finds a niche All bottom-up

22 22 How does this apply to organizations? To ensure innovation: Sounds simple doesn’t it? Creation and trial Encourage the prolific generation and trial of new ideas. Establishing successful variants Allow new ideas to flourish or wither based on how well they do.

23 23 Initial funding Prospect of failure ApprovalsEstablishment Biological evolution Capitalism in the small. Nature always experiments. Most are failures, which means death. (But no choice given.) None. Bottom-up resource allocation defines success. Entrepreneur Little needed for an Internet experiment. Perhaps some embarrassment, time, money; not much more. Few. Entrepreneur wants rewards. Bottom-up resource allocation. Bureaucracy Proposals, competition, forms, etc. When 100% Mission Success is the group goal who wants a failure in his/her personnel file? Far too many. Managers have other priorities. Top-down resource allocation. New ideas aren’t the problem. Trying them out Innovation in various environments Getting good ideas established We save ourselves by spin-doctoring and benign neglect

24 24 Evolution and exploratory behavior Exploratory behavior typically requires autonomous individuals. But much exploratory behavior is wasted effort. Success generally depends on more than a single lone inventor. –Successful exploratory behavior typically requires multiple, loosely coordinated, i.e., autonomous, individuals. One may hit the jackpot while the others drill dry holes. For a group to benefit from the discoveries of individuals, there must be mechanisms that bring those discoveries back into the group and allow them to take root. –Establishment is often built into a group’s process. –At the evolutionary level—including our hyper-evolutionary global society—this frequently requires “creative destruction,” which is often far more difficult to accept. Exploratory behavior typically requires autonomous individuals. But much exploratory behavior is wasted effort. Success generally depends on more than a single lone inventor. –Successful exploratory behavior typically requires multiple, loosely coordinated, i.e., autonomous, individuals. One may hit the jackpot while the others drill dry holes. For a group to benefit from the discoveries of individuals, there must be mechanisms that bring those discoveries back into the group and allow them to take root. –Establishment is often built into a group’s process. –At the evolutionary level—including our hyper-evolutionary global society—this frequently requires “creative destruction,” which is often far more difficult to accept. Markets are how we integrate creative destruction into society. Ant foraging; building out the circulatory system. Schumpeter

25 25 Implications for C2 There is no “commander’s intent” in nature or in the market. But there is something like (commander’s) intent in organisms. How do successful organisms work? A simplified model. –Lower levels discover opportunities through exploratory behavior. Constrained by “rules of engagement,” which protect them from harm. Initiatives often grow from the “edges,” where perception occurs. –Higher levels provide perspective and impose constraints. They do not primarily issue commands. Additional resources recruited as success builds—if it does. But lots of opportunities to withhold support or shape direction. This is a bottom-up model of resource allocation. Decisions about increasingly significant commitments made at increasingly higher levels. If entire organism commits, becomes “commanders intent.” To implement this model one should stay healthy and build skills and capabilities, which can be recruited/applied/committed when relevant. Different from starting with limited and narrowly focused top-level missions, goals, and objectives. Top-level mission is to survive, to build skills, and to ensure an environment within which this process can proceed and the organism can thrive. There is no “commander’s intent” in nature or in the market. But there is something like (commander’s) intent in organisms. How do successful organisms work? A simplified model. –Lower levels discover opportunities through exploratory behavior. Constrained by “rules of engagement,” which protect them from harm. Initiatives often grow from the “edges,” where perception occurs. –Higher levels provide perspective and impose constraints. They do not primarily issue commands. Additional resources recruited as success builds—if it does. But lots of opportunities to withhold support or shape direction. This is a bottom-up model of resource allocation. Decisions about increasingly significant commitments made at increasingly higher levels. If entire organism commits, becomes “commanders intent.” To implement this model one should stay healthy and build skills and capabilities, which can be recruited/applied/committed when relevant. Different from starting with limited and narrowly focused top-level missions, goals, and objectives. Top-level mission is to survive, to build skills, and to ensure an environment within which this process can proceed and the organism can thrive.

26 26 Evolution and quality Markets ensure a reasonably high level of quality by letting many variants appear and selecting the good ones. –To do this requires the ability to recognize quality when one sees it means to generate lots of variants the luxury of allowing low quality items come into being and then be rejected. –If these pertain, quality is (relatively) easy. Centralized control ensures quality by rigid oversight. –To do this requires that one know in advance how to produce quality and the means to ensure the knowledge is applied. –This is much harder.

27 27 Evolution and Markets All the mechanism we have seen are controlled evolution. They enable creative destruction without violence. For the most part, competition is for resources and not head-to-head conquest –Rivals rather than adversaries. Cannot attack the other directly. The bottom line is competition for resources. But advertizing and other forms of marketing and mass influence attempts to get around this. So do attempts to shape the environment which are carried out by entrenched interests.


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