Complexity & Systems
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Reaction-Diffusion Processes on Interconnected Scale-Free Networks

We study the two particle annihilation reaction A+B->Ø A+B→∅ on interconnected scale free networks. We show that the mixing of particles and the evolution of the process are influenced by the number of interconnecting links and by their functional properties, while surprisingly when the interconnecting links have the same function as the links within the networks, they are not affected by the interconnectivity strategies in use. Due to the better mixing, which suppresses the segregation effect, we show that the reaction rates are faster than what was observed in other topologies, in-line with previous studies performed on single scale free networks.

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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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The Hidden Power Laws of Ecosystems - Issue 29: Scaling - Nautilus

The Hidden Power Laws of Ecosystems - Issue 29: Scaling - Nautilus | Complexity & Systems | Scoop.it
Here’s how to cause a ruckus: Ask a bunch of naturalists to simplify the world. We usually think in terms of a web of complicated…
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Gary Bamford's curator insight, November 1, 2015 3:52 PM

The complexity of complexity!

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case-based modeling, case based modeling, sacs toolkit, brian castellani, rajeev rajaram, sociology and complexity, complexity map

case-based modeling, case based modeling, sacs toolkit, brian castellani, rajeev rajaram, sociology and complexity, complexity map | Complexity & Systems | Scoop.it
sociology and complexity science web
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Understanding the group dynamics and success of teams

Complex problems often require coordinated group effort and can consume significant resources, yet our understanding of how teams form and succeed has been limited by a lack of large-scale, quantitative data. We analyse activity traces and success levels for approximately 150 000 self-organized, online team projects. While larger teams tend to be more successful, workload is highly focused across the team, with only a few members performing most work. We find that highly successful teams are significantly more focused than average teams of the same size, that their members have worked on more diverse sets of projects, and the members of highly successful teams are more likely to be core members or ‘leads’ of other teams. The relations between team success and size, focus and especially team experience cannot be explained by confounding factors such as team age, external contributions from non-team members, nor by group mechanisms such as social loafing. Taken together, these features point to organizational principles that may maximize the success of collaborative endeavours.

 

Understanding the group dynamics and success of teams
Michael Klug, James P. Bagrow

Royal Society Open Science

http://dx.doi.org/10.1098/rsos.160007


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The systems approach: theory for practice

The systems approach: theory for practice | Complexity & Systems | Scoop.it
Over the past 4 years I have written a good number of posts on various aspects of the systems approach. In this post I will re-arrange more than 30 of them, to provide a more or less coherent body of theoretical insights underlying  Wicked Solutions. Along the way you will learn why “it is tempting, if the…
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The origins of the systems approach

The origins of the systems approach | Complexity & Systems | Scoop.it
Churchman's personal journey This post about the origins (and future!) of the systems approach is a bit complicated. You may prefer to get yourself intellectually geared up by first reading my previous post on the reasons why people don't apply the systems approach more often. Biography of the systems approach          In the first chapter of…
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Systems of Interaction between the First Sedentary Villages in the Near East Exposed Using Agent-Based Modelling of Obsidian Exchange

Systems of Interaction between the First Sedentary Villages in the Near East Exposed Using Agent-Based Modelling of Obsidian Exchange | Complexity & Systems | Scoop.it
In the Near East, nomadic hunter-gatherer societies became sedentary farmers for the first time during the transition into the Neolithic. Sedentary life presented a risk of isolation for Neolithic groups. As fluid intergroup interactions are crucial for the sharing of information, resources and genes, Neolithic villages developed a network of contacts. In this paper we study obsidian exchange between Neolithic villages in order to characterize this network of interaction. Using agent-based modelling and elements taken from complex network theory, we model obsidian exchange and compare results with archaeological data. We demonstrate that complex networks of interaction were established at the outset of the Neolithic and hypothesize that the existence of these complex networks was a necessary condition for the success and spread of a new way of living.
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[1406.5955] Simple universal models capture all spin physics

[1406.5955] Simple universal models capture all spin physics | Complexity & Systems | Scoop.it
Spin models are used in virtually every study of complex systems---be it condensed matter physics [1-4], neural networks [5] or economics [6,7]---as they exhibit very rich macroscopic behaviour despite their microscopic simplicity. It has long been known that by coarse-graining the system, the low energy physics of the models can be classified into different universality classes [8]. Here we establish a counterpart to this phenomenon: by "fine-graining" the system, we prove that all the physics of every classical spin model is exactly reproduced in the low energy sector of certain `universal models'. This means that (i) the low energy spectrum of the universal model is identical to the entire spectrum of the original model, (ii) the corresponding spin configurations are exactly reproduced, and (iii) the partition function is approximated to any desired precision. We prove necessary and sufficient conditions for a spin model to be universal, which show that complexity in the ground state alone is sufficient to reproduce full energy spectra. We use this to show that one of the simplest and most widely studied models, the 2D Ising model with fields, is universal.
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The essence of the systems approach

The essence of the systems approach | Complexity & Systems | Scoop.it
Why 'Wicked Solutions' works? Wicked problems now recognized         There was a time when wicked problems did not seem to exist. No matter how complex the problem, there was a general belief that a solution could be found, more typically by so-called linear problem solving methods. This changed in the early 1960s when Horst Rittel found…
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Jean-Michel Coron - "La régulation des systèmes complexes depuis Maxwell"

BnF - 11 mai 2011 Conférence donnée dans le cadre du cycle "Un texte, un mathématicien", organisée par la Société…
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[1602.02540] Variations on chaos in physics: from unpredictability to universal laws

[1602.02540] Variations on chaos in physics: from unpredictability to universal laws | Complexity & Systems | Scoop.it

The tremendous popular success of Chaos Theory shares some common points with the not less fortunate Relativity: they both rely on a misunderstanding. Indeed, ironically , the scientific meaning of these terms for mathematicians and physicists is quite opposite to the one most people have in mind and are attracted by. One may suspect that part of the psychological roots of this seductive appeal relies in the fact that with these ambiguous names, together with some superficial clichés or slogans immediately related to them ("the butterfly effect" or "everything is relative"), some have the more or less secret hope to find matter that would undermine two pillars of science, namely its ability to predict and to bring out a universal objectivity. Here I propose to focus on Chaos Theory and illustrate on several examples how, very much like Relativity, it strengthens the position it seems to contend with at first sight: the failure of predictability can be overcome and leads to precise, stable and even more universal predictions.

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[1601.06176] What is Information?

[1601.06176] What is Information? | Complexity & Systems | Scoop.it

Information is a precise concept that can be defined mathematically, but its relationship to what we call "knowledge" is not always made clear. Furthermore, the concepts "entropy" and "information", while deeply related, are distinct and must be used with care, something that is not always achieved in the literature. In this elementary introduction, the concepts of entropy and information are laid out one by one, explained intuitively, but defined rigorously. I argue that a proper understanding of information in terms of prediction is key to a number of disciplines beyond engineering, such as physics and biology.

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SIR-Network Model and Its Application to Dengue Fever

SIR-Network Model and Its Application to Dengue Fever | Complexity & Systems | Scoop.it

The SIR-network model, introduced in [S. Boatto et al., SIR-Network Model for Epidemics Dynamics in a City, in preparation] and [L. Stolerman, Spreading of an Epidemic over a City: A Model on Networks, Master's thesis, 2012 (in Portuguese)], deals with the propagation of disease epidemics in highly populated cities. The nodes, or vertices, are the city's neighborhoods, in which the local populations are assumed to be well-mixed. The directed edges represent the fractions of people moving from their neighborhoods of residence to those of daily activities. First, we present some fundamental properties of the basic reproduction number ($R_o$) for this model. In particular, we focus on how $R_o$ depends upon the geometry and the heterogeneity (different infection rates in each vertex) of the network. This allows us to conclude whether an epidemic outbreak can be expected or not. Second, we submit the SIR-network model to data fitting, using data collected during the 2008 Rio de Janeiro dengue fever epidemic. Important conclusions are drawn from the fitted parameters, and we show that improved results are found when a time-dependent infection parameter is introduced.


Read More: http://epubs.siam.org/doi/10.1137/140996148

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Complex Adaptive Systems Modeling | Full text | In Memoriam: John Henry Holland—a pioneer of complex adaptive systems research (February 2, 1929–August 9, 2015)

“The study of cas is a difficult, exciting task. The returns are likely to be proportionate to the difficulty.” Holland ([2006])

On August 9, 2015, cancer took Prof. John Henry Holland away from us. Prof. Holland was a pioneer of Complex Adaptive Systems (CAS) research and a true inspiration. He is known not only for his work on CAS, Holland ([1962], [1992])—which he would fondly write as “cas”—but also for his seminal work on adaptation in natural and artificial systems leading to the creation of genetic algorithms and eventually the fields of evolutionary computation, Holland ([1995]) and Learning Classifier Systems, Holland and Holyoak ([1989]).

Holland was a truly interdisciplinary academic. He had an undergraduate degree in Physics from MIT (1950), an M.A. in Mathematics (1954) and possibly the first ever PhD in Computer Science (1959), both from the University of Michigan—a place where he also subsequently served as a Professor of Psychology, Electrical Engineering and Computer Science.

Holland leaves behind his legacy in the form of a large number of thought-provoking articles, video lectures, books, and inspired people—ranging from colleagues, fellows and students to budding complexity enthusiasts. Two of his recent books summarize his views on CAS in both a longer, Holland ([2012]) as well as a shorter form, Holland ([2014]). It is easy to foresee that these works will serve not only as a guide to CAS but also guidance for future generations. Holland will indeed be greatly missed.

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Collapse des systèmes complexes

Collapse des systèmes complexes | Complexity & Systems | Scoop.it

Pourquoi parler d’effondrement et de collapse de notre civilisation ? Parce que le faisceau d’informations factuelles est très convergent, parce que cela a à voir avec les systèmes complexes, et parce que la résilience, individuelle et collective, commence par l’acceptation de la réalité telle qu’elle est.


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Pierre Mongin 's curator insight, April 28, 4:14 AM
juin excellente synthése du film Demain 
Jürgen Kanz's curator insight, May 1, 11:57 AM
The authors are referring to the paper of Graham M. Turner "On the cusp of global collapse?". This document is available here: https://www.ethz.ch/content/dam/ethz/special-interest/usys/ites/ecosystem-management-dam/documents/EducationDOC/Readings_DOC/Turner_2012_GAIA_LimitsToGrowth.pdf
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Hybrid Societies: Challenges and Perspectives in the Design of Collective Behavior in Self-organizing Systems

Hybrid societies are self-organizing, collective systems, which are composed of different components, for example, natural and artificial parts (bio-hybrid) or human beings interacting with and through technical systems (socio-technical). Many different disciplines investigate methods and systems closely related to the design of hybrid societies. A stronger collaboration between these disciplines could allow for re-use of methods and create significant synergies. We identify three main areas of challenges in the design of self-organizing hybrid societies. First, we identify the formalization challenge. There is an urgent need for a generic model that allows a description and comparison of collective hybrid societies. Second, we identify the system design challenge. Starting from the formal specification of the system, we need to develop an integrated design process. Third, we identify the challenge of interdisciplinarity. Current research on self-organizing hybrid societies stretches over many different fields and hence requires the re-use and synthesis of methods at intersections between disciplines. We then conclude by presenting our perspective for future approaches with high potential in this area.

 

Hybrid Societies: Challenges and Perspectives in the Design of Collective Behavior in Self-organizing Systems

Heiko Hamann, Yara Khaluf, Jean Botev, Mohammad Divband Soorati, Eliseo Ferrante, Oliver Kosak, Jean-Marc Montanier, Sanaz Mostaghim, Richard Redpath, Jonathan Timmis, Frank Veenstra, Mostafa Wahby, Aleš Zamuda
Front. Robot. AI, 11 April 2016 | http://dx.doi.org/10.3389/frobt.2016.00014


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Systems tinkering versus systems thinking - All Things ITSM

Systems tinkering versus systems thinking - All Things ITSM | Complexity & Systems | Scoop.it
Systems Thinking, is well suited to mass customization and knowledge work.Dealing with complex systems requires an experimental ‘systems tinkering’ approach
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How Diversity Makes Us Smarter

How Diversity Makes Us Smarter | Complexity & Systems | Scoop.it
Being around people who are different from us makes us more creative, more diligent and harder-working

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Marcelo Errera's curator insight, March 23, 1:33 PM
Indeed, as new ideas flow across groups of people, new degrees of freedom become available in the design evolution process.

It's a physics phenomenon.

Lexie stroud's curator insight, April 4, 9:54 AM
Although many people, specifically from homogenous groups, might argue this, I think it is an interesting concept. I think that it is a good thing for people of different backgrounds to come together and find ways to effectively solve problems. It seems obvious that they might be better at it. L.S.
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Some problems with the systems approach

Some problems with the systems approach | Complexity & Systems | Scoop.it
Some problems with the systems approach Why isn't it applied more often? Simple explanations        I am convinced that the systems approach is a very good thing. Like many 'believers' it is hard for me to understand why so many people think otherwise. In other words, how non-systems practitioners can think that they can and must address…
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The systems approach according to Churchman

The systems approach according to Churchman | Complexity & Systems | Scoop.it
The environmental fallacy and other notions The systems approach and its enemies      Too often human realities are ignored, with the result that planning efforts are sterile, unsatisfying, and irrelevant. In 'The systems approach and its enemies' (1979), Churchman draws on his wide and deep experience as a both a thinker and planner to show that…
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[1602.09054] Lyapunov Indices and the Poincaré Mapping in a Study of the Stability of the Krebs Cycle

[1602.09054] Lyapunov Indices and the Poincaré Mapping in a Study of the Stability of the Krebs Cycle | Complexity & Systems | Scoop.it
On the basis of a mathematical model, we continue the study of the metabolic Krebs cycle (or the tricarboxilic acid cycle). For the first time, we consider its consistency and stability, which depend on the dissipation of a transmembrane potential formed by the respiratory chain in the plasmatic membrane of a cell. The phase-parametric characteristic of the dynamics of the ATP level depending on a given parameter is constructed. The scenario of formation of multiple autoperiodic and chaotic modes is presented. Poincar\'{e} sections and mappings are constructed. The stability of modes and the fractality of the obtained bifurcations are studied. The full spectra of Lyapunov indices, divergences, KS-entropies, horizons of predictability, and Lyapunov dimensionalities of strange attractors are calculated. Some conclusions about the structural-functional connections determining the dependence of the cell respiration cyclicity on the synchronization of the functioning of the tricarboxilic acid cycle and the electron transport chain are presented.
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Measuring the Complexity of Continuous Distributions

Measuring the Complexity of Continuous Distributions | Complexity & Systems | Scoop.it

We extend previously proposed measures of complexity, emergence, and self-organization to continuous distributions using differential entropy. Given that the measures were based on Shannon’s information, the novel continuous complexity measures describe how a system’s predictability changes in terms of the probability distribution parameters. This allows us to calculate the complexity of phenomena for which distributions are known. We find that a broad range of common parameters found in Gaussian and scale-free distributions present high complexity values. We also explore the relationship between our measure of complexity and information adaptation.

 

Measuring the Complexity of Continuous Distributions
Guillermo Santamaría-Bonfil, Nelson Fernández,  and Carlos Gershenson

Entropy 2016, 18(3), 72

http://www.mdpi.com/1099-4300/18/3/72


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Gérard Ben Arous - "Paul Lévy et les cygnes noirs"

BnF - 30 avril 2014 Conférence donnée dans le cadre du cycle "Un texte, un mathématicien", organisée par la Société…
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The Many Careers of Jay Forrester - MIT Technology Review

The Many Careers of Jay Forrester - MIT Technology Review | Complexity & Systems | Scoop.it
Computing pioneer Jay Forrester, SM ’45, developed magnetic-core memory. Then he founded the field of system dynamics. Those are just two of his varied pursuits.

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The physics of life

The physics of life | Complexity & Systems | Scoop.it
From flocking birds to swarming molecules, physicists are seeking to understand 'active matter' — and looking for a fundamental theory of the living world.

 

http://www.nature.com/news/the-physics-of-life-1.19105


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Marcelo Errera's curator insight, January 13, 1:09 PM

Organization emerges naturally. One more manifestation of the constructal law.

 

By the way, soon to appear:

The Physics of Life: The Evolution of Everything 
by Adrian Bejan 
Link: http://amzn.com/1250078822

Francisco Restivo's curator insight, January 14, 6:29 PM

Living world is the real laboratory.

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Fast and slow thinking -- of networks: The complementary 'elite' and 'wisdom of crowds' of amino acid, neuronal and social networks

Fast and slow thinking -- of networks: The complementary 'elite' and 'wisdom of crowds' of amino acid, neuronal and social networks | Complexity & Systems | Scoop.it

Complex systems may have billion components making consensus formation slow and difficult. Recently several overlapping stories emerged from various disciplines, including protein structures, neuroscience and social networks, showing that fast responses to known stimuli involve a network core of few, strongly connected nodes. In unexpected situations the core may fail to provide a coherent response, thus the stimulus propagates to the periphery of the network. Here the final response is determined by a large number of weakly connected nodes mobilizing the collective memory and opinion, i.e. the slow democracy exercising the 'wisdom of crowds'. This mechanism resembles to Kahneman's "Thinking, Fast and Slow" discriminating fast, pattern-based and slow, contemplative decision making. The generality of the response also shows that democracy is neither only a moral stance nor only a decision making technique, but a very efficient general learning strategy developed by complex systems during evolution. The duality of fast core and slow majority may increase our understanding of metabolic, signaling, ecosystem, swarming or market processes, as well as may help to construct novel methods to explore unusual network responses, deep-learning neural network structures and core-periphery targeting drug design strategies.

 (Illustrative videos can be downloaded from here:this http URL)


Fast and slow thinking -- of networks: The complementary 'elite' and 'wisdom of crowds' of amino acid, neuronal and social networks
Peter Csermely

http://arxiv.org/abs/1511.01238 ;


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Complexity Digest's curator insight, November 18, 2015 6:13 PM

See Also: http://networkdecisions.linkgroup.hu 

António F Fonseca's curator insight, November 23, 2015 3:30 AM

Interesting  paper about fast cores and slow periphery,  conflict in the elite vs democratic consensus.

Marcelo Errera's curator insight, November 24, 2015 11:32 AM

Yes, there must be few fasts and many slows.  It's been predicted by CL in many instances.

 

http://www.researchgate.net/publication/273527384_Constructal_Law_Optimization_as_Design_Evolution

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Nature’s Critical Warning System | Quanta Magazine

Nature’s Critical Warning System |  Quanta Magazine | Complexity & Systems | Scoop.it

Scientists are homing in on a warning signal that arises in complex systems like ecological food webs, the brain and the Earth’s climate. Could it help prevent future catastrophes?

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