Complexity & Systems
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Complexity & Systems
Complex systems present problems both in mathematical modelling and philosophical foundations. The study of complex systems represents a new approach to science that investigates how relationships between parts give rise to the collective behaviors of a system and how the system interacts and forms relationships with its environment. The equations from which models of complex systems are developed generally derive from statistical physics, information theory and non-linear dynamics, and represent organized but unpredictable behaviors of natural systems that are considered fundamentally complex.  wikipedia (en)
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A Network Characteristic That Correlates Environmental and Genetic Robustness

A Network Characteristic That Correlates Environmental and Genetic Robustness | Complexity & Systems | Scoop.it

As scientific advances in perturbing biological systems and technological advances in data acquisition allow the large-scale quantitative analysis of biological function, the robustness of organisms to both transient environmental stresses and inter-generational genetic changes is a fundamental impediment to the identifiability of mathematical models of these functions. An approach to overcoming this impediment is to reduce the space of possible models to take into account both types of robustness. However, the relationship between the two is still controversial. This work uncovers a network characteristic, transient responsiveness, for a specific function that correlates environmental imperturbability and genetic robustness. We test this characteristic extensively for dynamic networks of ordinary differential equations ranging up to 30 interacting nodes and find that there is a power-law relating environmental imperturbability and genetic robustness that tends to linearity as the number of nodes increases. Using our methods, we refine the classification of known 3-node motifs in terms of their environmental and genetic robustness. We demonstrate our approach by applying it to the chemotaxis signaling network. In particular, we investigate plausible models for the role of CheV protein in biochemical adaptation via a phosphorylation pathway, testing modifications that could improve the robustness of the system to environmental and/or genetic perturbation.

 

 

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▶ Chaos, Complexity, and Public Policy - YouTube

Irene Sanders Executive Director and Founder of the Washington Center for Complexity and Public Policy and author of "Strategic Thinking and the New Science:...
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Zipf's Law for All the Natural Cities around the World

Two fundamental issues surrounding research on Zipf's law regarding city sizes are whether and why Zipf's law holds. This paper does not deal with the latter issue with respect to why, and instead investigates whether Zipf's law holds in a global setting, thus involving all cities around the world. Unlike previous studies, which have mainly relied on conventional census data, and census- bureau-imposed definitions of cities, we adopt naturally and objectively delineated cities, or natural cities, to be more precise, in order to examine Zipf's law. We find that Zipf's law holds remarkably well for all natural cities at the global level, and remains almost valid at the continental level except for Africa at certain time instants. We further examine the law at the country level, and note that Zipf's law is violated from country to country or from time to time. This violation is mainly due to our limitations; we are limited to individual countries, and to a static view on city-size distributions. The central argument of this paper is that Zipf's law is universal, and we therefore must use the correct scope in order to observe it. We further find that this law is reflected in the distribution of cities: the number of cities in individual countries follows an inverse power relationship; the number of cities in the first largest country is twice as many as that in the second largest country, three times as many as that in the third largest country, and so on.
Keywords: Cities, night-time imagery, city-size distributions, head/tail breaks, big data

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▶ System of Systems - YouTube

Video featuring, from IBM: Mike Wing, Irving Wladawsky-Berger and Julia Grace. If you look at our planet from space, what you see is something like a neural ...
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▶ NOVA scienceNOW : 34 - Emergence - YouTube

The seemingly coordinated movement of a school of fish or a flock of birds is not controlled by any leader. Instead, it emerges naturally as each individual ...
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SIMSOC: Recommendations for ABM videos | MASS

SIMSOC: Recommendations for ABM videos | MASS | Complexity & Systems | Scoop.it

I asked participants of the SIMSOC email list for recommendations of videos to show in agent-based modelling and complexity lectures. Thank you to everyone who replied. Here is a list of some useful resources:

Bernard Ryefield's insight:

lots of good links to videos on agent-based modelling

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How Santa Fe Ants Evolve

The Santa Fe Ant model problem has been extensively used to investigate, test and evaluate Evolutionary Computing systems and methods over the past two decades. There is however no literature on its program structures that are systematically used for fitness improvement, the geometries of those structures and their dynamics during optimization. This paper analyzes the Santa Fe Ant Problem using a new phenotypic schema and landscape analysis based on executed instruction sequences. For the first time we detail systematic structural features that give high fitness and the evolutionary dynamics of such structures. The new schema avoids variances due to introns. We develop a phenotypic variation method that tests the new understanding of the landscape. We also develop a modified function set that tests newly identified synchronization constraints. We obtain favorable computational efforts compared to those in the literature, on testing the new variation and function set on both the Santa Fe Trail, and the more computationally demanding Los Altos Trail. Our findings suggest that for the Santa Fe Ant problem, a perspective of program assembly from repetition of highly fit responses to trail conditions leads to better analysis and performance.

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How do life, economy and other complex systems escape the heat death?

The primordial confrontation underlying the existence of our universe can be conceived as the battle between entropy and complexity. The law of ever-increasing entropy (Boltzmann H-theorem) evokes an irreversible, one-directional evolution (or rather involution) going uniformly and monotonically from birth to death. Since the 19th century, this concept is one of the cornerstones and in the same time puzzles of statistical mechanics. On the other hand, there is the empirical experience where one witnesses the emergence, growth and diversification of new self-organized objects with ever-increasing complexity. When modeling them in terms of simple discrete elements one finds that the emergence of collective complex adaptive objects is a rather generic phenomenon governed by a new type of laws. These 'emergence' laws, not connected directly with the fundamental laws of the physical reality, nor acting 'in addition' to them but acting through them were called by Phil Anderson 'More is Different', 'das Maass' by Hegel etc. Even though the 'emergence laws' act through the intermediary of the fundamental laws that govern the individual elementary agents, it turns out that different systems apparently governed by very different fundamental laws: gravity, chemistry, biology, economics, social psychology, end up often with similar emergence laws and outcomes. In particular the emergence of adaptive collective objects endows the system with a granular structure which in turn causes specific macroscopic cycles of intermittent fluctuations.

 

How do life, economy and other complex systems escape the heat death?
Sorin Solomon, Natasa Golo

http://arxiv.org/abs/1402.0153


Via Complexity Digest
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A Game Theoretic Analysis of Collaboration in Wikipedia

Peer production projects such as Wikipedia or open-source software development allow volunteers to collectively create knowledge based products. The inclusive nature of such projects poses difficult challenges for ensuring trustworthiness and combating vandalism. Prior studies in the area deal with descriptive aspects of peer production, failing to capture the idea that while contributors collaborate, they also compete for status in the community and for imposing their views on the product. In this paper we investigate collaborative authoring in Wikipedia where contributors append and overwrite previous contributions to a page. We assume that a contributors goal is to maximize ownership of content sections such that content owned (or originated) by her survived the most recent revision of the page. We model contributors interactions to increase their content ownership as a noncooperative game where a players utility is associated with content owned and cost is a function of effort expended. Our results capture several real life aspects of contributors interactions within peer production projects. We show that at the Nash equilibrium there is an inverse relationship between the effort required to make a contribution and the survival of a contributors content. In other words majority of the content that survives is necessarily contributed by experts who expend relatively less effort than non experts. An empirical analysis of Wikipedia articles provides support for our models predictions. Implications for research and practice are discussed in the context of trustworthy collaboration as well as vandalism.
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▶ Seven Complex Lessons in Education - Edgar Morin - Interview - YouTube

Dr. Edgar Morin, an eminent sociologist and philosopher, discusses his work on Seven Complex Lessons in Education for the Future, addressing themes related to knowledge, identity and shared global challenges.


Via jean lievens, Dina Gálvez
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Corina Ciechanow's curator insight, February 14, 2014 4:45 AM

'Il faut enseigner à la bienveillance' Teaching people how to show kindness, see all aspects of others to understand them. Great interview!

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Edgar Morin's Path of Complexity

Edgar Morin's Path of Complexity | Complexity & Systems | Scoop.it
An extensive bio-bibliographical overview of the work of Edgar Morin, followed by a discussion of his "complex thought" in the context of the history of ideas.

Via Dina Gálvez
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Puppies! Now that I’ve got your attention, complexity theory

Animal behavior isn't complicated, but it is complex. Nicolas Perony studies how individual animals -- be they Scottish Terriers, bats or meerkats -- follow simple rules that, collectively, create larger patterns of behavior. And how this complexity born of simplicity can help them adapt to new circumstances, as they arise.
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Dmitry Alexeev's curator insight, February 3, 2014 1:21 AM

gotta save for alter

 

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To react or not to react? Intrinsic stochasticity of human control in virtual stick balancing

Understanding how humans control unstable systems is central to many research problems, with applications ranging from quiet standing to aircraft landing. Much evidence appears in favor of event-driven control hypothesis: human operators are passive by default and only start actively controling the system when the discrepancy between the current and desired system states becomes in some sense large. The present paper argues that the control triggering mechanism in humans is intrinsically stochastic. We propose a model which captures the stochastic threshold mechanism and show that it matches the experimental data on human balancing of virtual overdamped stick. Our results suggest that the stochasticity of the threshold mechanism is a fundamental property and may play an important role in the dynamics of human-controlled systems.

 

Arkady Zgonnikov, Ihor Lubashevsky, Shigeru Kanemoto, Toru Miyazawa, Takashi Suzuki

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The Pre-History of Urban Scaling

The Pre-History of Urban Scaling | Complexity & Systems | Scoop.it

Cities are increasingly the fundamental socio-economic units of human societies worldwide, but we still lack a unified characterization of urbanization that captures the social processes realized by cities across time and space. This is especially important for understanding the role of cities in the history of human civilization and for determining whether studies of ancient cities are relevant for contemporary science and policy. As a step in this direction, we develop a theory of settlement scaling in archaeology, deriving the relationship between population and settled area from a consideration of the interplay between social and infrastructural networks. We then test these models on settlement data from the Pre-Hispanic Basin of Mexico to show that this ancient settlement system displays spatial scaling properties analogous to those observed in modern cities. Our data derive from over 1,500 settlements occupied over two millennia and spanning four major cultural periods characterized by different levels of agricultural productivity, political centralization and market development. We show that, in agreement with theory, total settlement area increases with population size, on average, according to a scale invariant relation with an exponent in the range . As a consequence, we are able to infer aggregate socio-economic properties of ancient societies from archaeological measures of settlement organization. Our findings, from an urban settlement system that evolved independently from its old-world counterparts, suggest that principles of settlement organization are very general and may apply to the entire range of human history.

 

 

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Agent-based modeling and simulation of emergent behavior in air transportation

Agent-based modeling and simulation of emergent behavior in air transportation | Complexity & Systems | Scoop.it

Commercial aviation is feasible thanks to the complex socio-technical air transportation system, which involves interactions between human operators, technical systems, and procedures. In view of the expected growth in commercial aviation, significant changes in this socio-technical system are in development both in the USA and Europe. Such a complex socio-technical system may generate various types of emergent behavior, which may range from simple emergence, through weak emergence, up to strong emergence. The purpose of this paper is to demonstrate that agent-based modeling and simulation allows identifying changed and novel rare emergent behavior in this complex socio-technical system.

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▶ Richard Feynman - The Distinction of Past and Future. Part 6 - YouTube

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Model Thinking

Model Thinking | Complexity & Systems | Scoop.it
Model Thinking is a free online class taught by Scott E. Page of University of Michigan
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▶ TEDxRotterdam - Igor Nikolic - Complex adaptive systems - YouTube

Igor Nikolic graduated in 2009 on his dissertation: co-evolutionary process for modelling large scale socio-technical systems evolution. He received his MSc ...
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Exploring Chaos, Fractals and Bifurcation

Exploring Chaos, Fractals and Bifurcation | Complexity & Systems | Scoop.it
As you may have seen, I am currently really enjoying a course on Dynamic Systems and Chaos run by Santa Fe Institute (see Thoughts on Santa Fe’s new MOOC – Introduction to Dynamical Systems and Cha...
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Mikko Hakala's curator insight, February 10, 2014 4:07 PM

Fascinating. "...we begin to really grasp the extraordinary complex and chaotic behaviour of what we thought may be an innocuous looking equation. As well as the fractal like patterns, we also notice structure within the chaos..."

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Case Based Method and Complexity Science, Part II (The SACS Toolkit)

Case Based Method and Complexity Science, Part II (The SACS Toolkit) | Complexity & Systems | Scoop.it

My goal here is to introduce the case-based complexity science method my colleagues and I have developed for modeling complex systems. Our case-based modeling technique is called the SACS Toolkit--which stands for the Sociology and Complexity Science Toolkit.


Via Dr. Susan Bainbridge
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E. Morin’s Complexity Paradigm in the Context of Informational Challenges to Education

E. Morin’s Complexity Paradigm in the Context of Informational Challenges to Education | Complexity & Systems | Scoop.it

The network nature of informational society is analyzed for understanding the challenges to contemporary education. Becoming of this society actualizes the need for lifelong learning, self-study, the reorientation of thinking style. The author attempts to explicate the methodological potential of E.Morin’s complexity paradigm for comprehension of informational challenges to education. Morin’s anthropo-ethics is investigated as a conceptual demonstration of the new paradigm in humanities. From the complexity paradigm perspective the education is viewed as transphenomenal by its nature with the transdisciplinary character of cognition, and the transdiscursive essence of educational thoughts. The education has to redefine its main didactic principles from a controlled and controlling discipline-based education, predicted targets towards a discovered, transdisciplinary, developing curriculum. The author underlines that the complexity-based curriculum should be oriented to multidimensional nature of a human being, because education is declared to stimulate the inner potential of a human and create the educational conditions for complexity thinking becoming.

 

 

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Science in a Complex World: Declassification of data important to future science

Science in a Complex World: Declassification of data important to future science | Complexity & Systems | Scoop.it
Did you know top-secret intelligence by the U.S. government has played a key role in helping scientists understand how human societies and ecosystems have evolved over the last 10,000 years?
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Double percolation phase transition in clustered complex networks

We perform an extensive numerical study of the effects of clustering on the structural properties of complex networks. We observe that strong clustering in heterogeneous networks induces the emergence of a core-periphery organization that has a critical effect on their percolation properties. In such situation, we observe a novel double phase transition, with an intermediate phase where only the core of the network is percolated, and a final phase where the periphery percolates regardless of the core. Interestingly, strong clustering makes simultaneously the core more robust and the periphery more fragile. These phenomena are also found in real complex networks.

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Introduction to Complex Systems: Patterns in Nature

This video provides a basic introduction to the science of complex systems, focusing on patterns in nature. (For more information on agent-based modeling, vi...

Via Lorien Pratt
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António F Fonseca's curator insight, February 1, 2014 4:50 AM

Agent based modeling still is the best tool to understand complex systems when mathematical modeling gets very complicated.

Liz Rykert's curator insight, February 10, 2014 7:25 PM

Always looking for good resources to introduce complexity science to others. This looks great. 

Ian Biggs, FAIPM, CPPE's curator insight, April 16, 2014 8:08 PM

I recently conducted a series of workshops on the subject of 'Complex Project Management - Navigating through the unknown'. This clip provides a great introduction to complex systems and for those interested in Complexity Science, this clip is worth 7:52 of your time.