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Towards a rigorous framework for studying 2-player continuous games

Towards a rigorous framework for studying 2-player continuous games | Papers | Scoop.it

The use of 2-player strategic games is one of the most common frameworks for studying the evolution of economic and social behavior. Games are typically played between two players, each given two choices that lie at the extremes of possible behavior (e.g. completely cooperate or completely defect). Recently there has been much interest in studying the outcome of games in which players may choose a strategy from the continuous interval between extremes,... A case study is then presented demonstrating the misclassification that can result from the extension of discrete games into continuous space.

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Chaotic Ising-like dynamics in traffic signals

Chaotic Ising-like dynamics in traffic signals | Papers | Scoop.it

The green and red lights of a traffic signal can be viewed as the up and down states of an Ising spin. Moreover, traffic signals in a city interact with each other, if they are controlled in a decentralised way. In this paper, a simple model of such interacting signals on a finite-size two-dimensional lattice is shown to have Ising-like dynamics that undergoes a ferromagnetic phase transition. Probabilistic behaviour of the model is realised by chaotic billiard dynamics that arises from coupled non-chaotic elements. This purely deterministic model is expected to serve as a starting point for considering statistical mechanics of traffic signals.

 

Chaotic Ising-like dynamics in traffic signals

Hideyuki Suzuki, Jun-ichi Imura & Kazuyuki Aihara

Scientific Reports 3, Article number: 1127 http://dx.doi.org/10.1038/srep01127

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Perspectives on a Hyperconnected World: Insights from the Science of Complexity

by the World Economic Forum’s Global Agenda Council on Complex Systems

 

Every day our world becomes more complex and dynamic. The global population continues to rise with urbanization occurring at an exponential rate. Economic growth brings people from diverse cultures and regions into contact with one another through increased trade and travel. The Internet and social media now seem to connect each person to everyone else, and to make information available to all.

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Ellie Kesselman Wells's comment, January 27, 2013 1:43 PM
They were quite wise not to explicitly mention Davos. This is what should be discussed at Davos, not celebrity photos! Thank you for sharing with us, Dr. Nooo!
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Cytosystems dynamics in self-organization of tissue architecture

Cytosystems dynamics in self-organization of tissue architecture | Papers | Scoop.it

Our knowledge of the principles by which organ architecture develops through complex collective cell behaviours is still limited. Recent work has shown that the shape of such complex tissues as the optic cup forms by self-organization in vitro from a homogeneous population of stem cells. Multicellular self-organization involves three basic processes that are crucial for the emergence of latent intrinsic order. Based on lessons from recent studies, cytosystems dynamics is proposed as a strategy for understanding collective multicellular behaviours, incorporating four-dimensional measurement, theoretical modelling and experimental reconstitution.

 

Cytosystems dynamics in self-organization of tissue architecture

Yoshiki Sasai
Nature 493, 318–326 (17 January 2013)

http://dx.doi.org/10.1038/nature11859

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Video Article: Embracing Complexity

Video Article: Embracing Complexity | Papers | Scoop.it

Your grade ten math teacher probably wrote this several times on your tests: SIMPLIFY. And, for much of science, that’s part of the work: SIMPLIFY. The universe can be broken down into smaller and smaller chunks in an attempt to find its most basic level and functions. But what do you do when that doesn’t work? Complex systems that defy reduction are all around us, from the elaborate workings of an ant colony—which could never be predicted from the physiology of a single ant—to fluctuations in the financial system that can send ripples around the globe. When broken into their constituent pieces, examined and put back together, such systems do not behave as expected. The sum of the parts does not equal the whole

 

Interview to Raissa D’Souza by Graeme Stemp Morlock

http://www.fqxi.org/community/articles/display/174

 

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starwalker's curator insight, January 28, 2013 4:17 AM

"I firmly believe networks become more interdependent in time," says D’Souza. "We see the global economy becoming more interdependent. We see Facebook making everyone more interconnected. We’re relying increasingly on technologies like the Internet and communications networks, for instance, the smart-grid, a cyber-physical system. All these networks that used to operate more independently are now becoming more interconnected, and to me that is really a signature of time."

Simon Gifford's curator insight, January 31, 2013 3:37 AM

Lengthy but interesting

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Self-organization and entropy reduction in a living cell

In this paper we discuss the entropy and information aspects of a living cell. Particular attention is paid to the information gain on assembling and maintaining a living state.

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Canalization and control in automata networks: body segmentation in Drosophila melanogaster

We present schema redescription as a methodology to characterize canalization in automata networks used to model biochemical regulation and signalling. In our formulation, canalization becomes synonymous with redundancy present in the logic of automata. This results in straightforward measures to quantify canalization in an automaton (micro-level), which is in turn integrated into a highly scalable framework to characterize the collective dynamics of large-scale automata networks (macro-level). This way, our approach provides a method to link micro- to macro-level dynamics -- a crux of complexity. Several new results ensue from this methodology: uncovering of dynamical modularity (modules in the dynamics rather than in the structure of networks), identification of minimal conditions and critical nodes to control the convergence to attractors, simulation of dynamical behaviour from incomplete information about initial conditions, and measures of macro-level canalization and robustness to perturbations. We exemplify our methodology with a well-known model of the intra- and inter cellular genetic regulation of body segmentation in Drosophila melanogaster.

 

Canalization and control in automata networks: body segmentation in Drosophila melanogaster

Manuel Marques-Pita, Luis M. Rocha

http://arxiv.org/abs/1301.5831

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The Evolutionary Ecology of Technological Innovations

Technological evolution has been compared to biological evolution by many authors over the last two centuries. As a parallel experiment of innovation involving economic, historical and social components, artifacts define a universe of evolving properties that displays episodes of diversification and extinction. Here we critically review previous work comparing the two types of evolution. Like biological evolution, technological evolution is driven by descent with variation and selection, and includes tinkering, convergence and contingency. At the same time there are essential differences that make the two types of evolution quite distinct. Major distinctions are illustrated by current specific examples, including the evolution of cornets and the historical dynamics of information technologies. Due to their fast and rich development, the later provide a unique opportunity to study technological evolution at all scales with unprecedented resolution. Despite the presence of patterns suggesting convergent trends between man-made systems end biological ones, they provide examples of planned design that have no equivalent with natural evolution.

 

The Evolutionary Ecology of Technological Innovations

Ricard V. Solé, Sergi Valverde, Marti Rosas Casals, Stuart Kauffman, Doyne Farmer, Niles Eldredge

SFI Working Paper 12-12-022

http://www.santafe.edu/research/working-papers/abstract/b1b04354b39d2aab7cbcc8a4ac97ef0e/

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Complejidady Economía's curator insight, January 25, 2013 11:00 AM

La Economía evolutiva de las innovaciones tecnológicas.

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Scaling behavior in probabilistic neuronal cellular automata

We study a neural network model of interacting stochastic discrete two-state cellular automata on a regular lattice. The system is externally tuned to a critical point which varies with the degree of stochasticity (or the effective temperature). There are avalanches of neuronal activity, namely, spatially and temporally contiguous sites of activity; a detailed numerical study of these activity avalanches is presented, and single, joint, and marginal probability distributions are computed. At the critical point, we find that the scaling exponents for the variables are in good agreement with a mean-field theory.

 

Kaustubh Manchanda, Avinash Chand Yadav, and Ramakrishna Ramaswamy

"Scaling behavior in probabilistic neuronal cellular automata"

Phys. Rev. E 87, 012704 (2013)

http://link.aps.org/doi/10.1103/PhysRevE.87.012704

 

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Social Dynamics of Science

Social Dynamics of Science | Papers | Scoop.it

The birth and decline of disciplines are critical to science and society. How do scientific disciplines emerge? No quantitative model to date allows us to validate competing theories on the different roles of endogenous processes, such as social collaborations, and exogenous events, such as scientific discoveries. Here we propose an agent-based model in which the evolution of disciplines is guided mainly by social interactions among agents representing scientists. Disciplines emerge from splitting and merging of social communities in a collaboration network. We find that this social model can account for a number of stylized facts about the relationships between disciplines, scholars, and publications. These results provide strong quantitative support for the key role of social interactions in shaping the dynamics of science. While several “science of science” theories exist, this is the first account for the emergence of disciplines that is validated on the basis of empirical data.

 

Social Dynamics of Science

Xiaoling Sun, Jasleen Kaur, Staša Milojević, Alessandro Flammini & Filippo Menczer

Scientific Reports 3, Article number: 1069 http://dx.doi.org/10.1038/srep01069

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Complex dynamics in learning complicated games

Writing in PNAS, a University of Manchester physicist has discovered that some games are simply impossible to fully learn, or too complex for the human mind to understand.

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Evolutionary Biology for the 21st Century

We live in an exciting time for biology. Technological advances have made data collection easier and cheaper than we could ever have imagined just 10 years ago. We can now synthesize and analyze large data sets containing genomes, transcriptomes, proteomes, and multivariate phenotypes. At the same time, society's need for the results of biological research has never been greater. Solutions to many of the world's most pressing problems—feeding a global population, coping with climate change, preserving ecosystems and biodiversity, curing and preventing genetically based diseases—will rely heavily on biologists, collaborating across disciplines.

 

Losos JB, Arnold SJ, Bejerano G, Brodie ED III, Hibbett D, et al. (2013) Evolutionary Biology for the 21st Century. PLoS Biol 11(1): e1001466. http://dx.doi.org/10.1371/journal.pbio.1001466

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Analytical investigation of self-organized criticality in neural networks

Dynamical criticality has been shown to enhance information processing in dynamical systems, and there is evidence for self-organized criticality in neural networks. A plausible mechanism for such self-organization is activity dependent synaptic plasticity. Here, we model neurons as discrete-state nodes on an adaptive network following stochastic dynamics. At a threshold connectivity, this system undergoes a dynamical phase transition at which persistent activity sets in. In a low dimensional representation of the macroscopic dynamics, this corresponds to a transcritical bifurcation. We show analytically that adding activity dependent rewiring rules, inspired by homeostatic plasticity, leads to the emergence of an attractive steady state at criticality and present numerical evidence for the system's evolution to such a state.

 

Analytical investigation of self-organized criticality in neural networks
Felix Droste, Anne-Ly Do, and Thilo Gross
Journal of the Royal Society Interface 78, 20120558, 2013.
arXiv:1203.4942

http://www.biond.org/node/327

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A Novel Analytical Method for Evolutionary Graph Theory Problems

Evolutionary graph theory studies the evolutionary dynamics of populations structured on graphs. A central problem is determining the probability that a small number of mutants overtake a population. Currently, Monte Carlo simulations are used for estimating such fixation probabilities on general directed graphs, since no good analytical methods exist. In this paper, we introduce a novel deterministic framework for computing fixation probabilities for strongly connected, directed, weighted evolutionary graphs under neutral drift.

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Evolution of fairness in the one-shot anonymous Ultimatum Game

Classical economic models assume that people are fully rational and selfish, while experiments often point to different conclusions. A canonical example is the Ultimatum Game: one player proposes a division of a sum of money between herself and a second player, who either accepts or rejects. Based on rational self-interest, responders should accept any nonzero offer and proposers should offer the smallest possible amount. Traditional, deterministic models of evolutionary game theory agree: in the one-shot anonymous Ultimatum Game, natural selection favors low offers and demands. Experiments instead show a preference for fairness: often responders reject low offers and proposers make higher offers than needed to avoid rejection. Here we show that using stochastic evolutionary game theory, where agents make mistakes when judging the payoffs and strategies of others, natural selection favors fairness. (...)

 

Evolution of fairness in the one-shot anonymous Ultimatum Game
David G. Rand, Corina E. Tarnita, Hisashi Ohtsuki and Martin A. Nowak

http://dx.doi.org/10.1073/pnas.1214167110
PNAS January 22, 2013

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Network Observability Transitions

In the modeling, monitoring, and control of complex networks, a fundamental problem concerns the comprehensive determination of the state of the system from limited measurements. Using power grids as example networks, we show that this problem leads to a new type of percolation transition, here termed a network observability transition, which we solve analytically for the configuration model. We also demonstrate a dual role of the network’s community structure, which both facilitates optimal measurement placement and renders the networks substantially more sensitive to ‘‘observability attacks.’’ Aside from their immediate implications for the development of smart grids, these results provide insights into decentralized biological, social, and technological networks.

 

Network Observability Transitions,
Y. Yang, J. Wang, and A. E. Motter,
Phys. Rev. Lett. 109, 258701 (2012).
http://prl.aps.org/abstract/PRL/v109/i25/e258701

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Time as a limited resource: Communication Strategy in Mobile Phone Networks

We used a large database of 9 billion calls from 20 million mobile users to examine the relationships between aggregated time spent on the phone, personal network size, tie strength and the way in which users distributed their limited time across their network (disparity). Compared to those with smaller networks, those with large networks did not devote proportionally more time to communication and had on average weaker ties (as measured by time spent communicating). Further, there were not substantially different levels of disparity between individuals, in that mobile users tend to distribute their time very unevenly across their network, with a large proportion of calls going to a small number of individuals. Together, these results suggest that there are time constraints which limit tie strength in large personal networks, and that even high levels of mobile communication do not fundamentally alter the disparity of time allocation across networks.

 

Time as a limited resource: Communication Strategy in Mobile Phone Networks

Giovanna Miritello, Esteban Moro, Rubén Lara, Rocío Martínez-López, Sam G. B. Roberts, Robin I. M. Dunbar

http://arxiv.org/abs/1301.2464

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High-speed Trading: Is It Time to Apply the Brakes?

High-speed Trading: Is It Time to Apply the Brakes? | Papers | Scoop.it

How fast is high-frequency stock trading? In the time it takes to read this sentence, tens of thousands of high-speed, computer-automated transactions can occur. Winning traders edge out rivals by intervals measured in nanoseconds. Fans of the practice say that high-frequency traders add crucial liquidity to the stock market. Critics dispute that claim and highlight, instead, lurking perils for the global financial system.

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Ellie Kesselman Wells's comment, January 27, 2013 1:45 PM
Yes! ;o) It is time. Thank you!
Ellie Kesselman Wells's curator insight, January 27, 2013 1:48 PM

Yes! It IS time for some greater introspection about this, before there are even worse problems. Right now, there is very little understanding of risks to most people, including the voting public. European regulators seem to have a more realistic view and be willing to act upon it than in the U.S.A.

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Imitation dynamics in a game of traffic

We study a model of traffic where drivers adopt different behavioral strategies. These can be cooperative or defective according to a driver abiding or not by a traffic rule. Drivers can change their strategy by imitating the majority, with a rule that depends on the strategies with which they have interacted. These interactions occur at intersections, where vehicles pay a temporal cost according to their strategy. We analyze the conditions under which different strategy compositions represent an advantage in the system velocity. We found that the cooperators' mean speed is higher than the defectors' even when the vehicle density is large. However, defectors can obtain benefits in their mean speed when they are a minority in an essentially cooperative population. The presence of a core of educated drivers, who persist firmly in a cooperative behavior, optimizes the speed in the system, especially for intermediate values of vehicular density and higher temporal costs.

 

Imitation dynamics in a game of traffic

Gabriel H. Paissan, Guillermo Abramson

http://arxiv.org/abs/1301.4130

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Ecosystems perspective on financial networks: diagnostic tools

The economical world consists of a highly interconnected and interdependent network of firms. Here we develop temporal and structural network tools to analyze the state of the economy. Our analysis indicates that a strong clustering can be a warning sign. Reduction in diversity, which was an essential aspect of the dynamics surrounding the crash in 2008, is seen as a key emergent feature arising naturally from the evolutionary and adaptive dynamics inherent to the financial markets. Similarly, collusion amongst construction firms in a number of regions in Japan in the 2000s can be identified with the formation of clusters of anomalous highly connected companies.

 

Ecosystems perspective on financial networks: diagnostic tools

Eduardo Viegas, Misako Takayasu, Wataru Miura, Koutarou Tamura, Takaaki Ohnishi, Hideki Takayasu, Henrik Jeldtoft Jensen

http://arxiv.org/abs/1301.5821

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Urban Scaling in Prehispanic Central Mexico

Despite the fact that cities are increasingly the fundamental socioeconomic units of human societies worldwide, a unified quantitative framework concerning urban form and function has yet to be established. As a step in this direction, we analyze settlement data from the Prehispanic Basin of Mexico to show that this system displays spatial scaling properties analogous to those observed for modern cities. Our data derive from some 1400 settlements occupied over two millennia and spanning four major cultural periods characterized by different levels of political centralization and socioeconomic development. We show that, for each period, total settlement area increases with population size according to a scale invariant relation, with exponent α= 2/3-5/6, in agreement with expectations of emerging theory. These findings, from an urban system that evolved independently from old-world cities, suggest that principles of human settlement organization are very general and may apply to the entire range of human history.

 

Urban Scaling in Prehispanic Central Mexico

Scott G. Ortman, Andrew Cabaniss, Luís M. A. Bettencourt

SFI Working Paper 13-01-001

http://www.santafe.edu/research/working-papers/abstract/00ab6dfb47d2e87e8b0455db4d5a49cb/

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Complexity, the science of cities and long-range futures

The emergence of a ‘science of cities’ provides the foundations for long-range futures research that may be applied to models of climate change, with a time horizon in excess of 150 years. The features of a complexity theory of cities have been developed at multiple levels with scientific analogies such as ecology, biology and physics. The following principles apply: 1. Complexity science unifies a wide variety of urban phenomena including emergence, technological evolution, civil phase transitions, macrolaws, and resilience to system failures and extreme events. 2. World urbanisation raises the number of levels in the urban hierarchy, with an increasing number of megacities with over 10 m inhabitants. 3. Urban development involves the institutional coordination of technological development with engineered transformations. 4. Civil and societal transitions arise with increasing per capita investment, such that some social norms and planning standards have consistent scaling factors across a range of city sizes for countries at similar stages of development. 5. The trajectory of the urban system depends upon the allometric pattern of growth for cities, and human settlements in 2150 will occupy less than 10% of the world's land area.

 

Complexity, the science of cities and long-range futures
Robert Hugh Samet

Futures

http://dx.doi.org/10.1016/j.futures.2013.01.006

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ComplexInsight's curator insight, January 22, 2013 6:29 PM

Not sure I agree with the suggestions made but an interesting read to ponder on.

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Ant foraging and geodesic paths in labyrinths: Analytical and computational results

Ant foraging and geodesic paths in labyrinths: Analytical and computational results | Papers | Scoop.it

In this paper we propose a mechanism for the formation of paths of minimal length between two points (trails) by a collection of individuals undergoing reinforced random walks. This is the case, for instance, of ant colonies in search for food and the development of ant trails connecting nest and food source.

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Collaboration is the New Competition

Five ways to drive large-scale social change by working cooperatively.

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ddrrnt's curator insight, January 12, 2013 2:19 AM

Leaders and organizations are acknowledging that even their best individual efforts can't stack up against today's complex and interconnected problems. They are putting aside self-interests and collaborating to build a new civic infrastructure to advance their shared objectives. It's called collective impact and it's a growing trend across the country. (...)

While collaboration is certainly not a foreign concept, what we're seeing around the country is the coming together of non-traditional partners, and a willingness to embrace new ways of working together. And, this movement is yielding promising results.

... five lessons for driving large-scale social change through collaboration:


  1. Clearly define what you can do together: As Dana O'Donovan of the Monitor Institute has noted, many organizations find collaboration to be messy and time consuming. From the very beginning, you must develop clarity of purpose and articulate, "What can we do together that we could not do alone?" (...)
  2. Transcend parochialism: Even the most well intended collaboration is often crippled by parochialism. Individual organizations earmark their participation and resources for activities that perfectly align with their own work or they use the collaboration platform as a way to get other participants to fund their own priorities. (...)
  3. Adapt to data: The complex, multidisciplinary problems that many collaborative projects tackle do not have easy fixes. These challenges require continuous learning and innovation and the use of real-time data to help participants understand what is and isn't working. Adjustments must be made on the fly. (...)
  4. Feed the field: You have an obligation to share what you learn — both the results and the methods for achieving them. Living Cities has long understood the value that our member institutions get by learning and working together. (...)
  5. Support the backbone: In our experience, progress is best achieved when a "backbone organization," keeps the group's work moving forward. Staff at these organizations ensure that work is completed between meetings, track data, enable adaptation, disseminate knowledge, and build buy-in and ownership from all participants.(...)

Ben Hecht

Ben Hecht is President & CEO of Living Cities, an organization that harnesses the collective knowledge of its 22 member foundations and financial institutions to benefit low income people and the cities where they live.



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Tipping points: From patterns to predictions

There has been much talk about tipping points over the past few years, and about the warning signals that may precede them. You could be forgiven for thinking that the forecasting of epidemics and stock-market crashes is just around the corner. But no one has yet managed to use the theory on early warning signals to predict a natural catastrophe.

The rewards of bridging the gap between the real world and mathematical conceptualizations of catastrophic shifts would be vast. Climate scientists might be able to foresee major shifts in the ocean currents with a rise in global temperatures; ecologists could potentially stave off pest outbreaks; and policies might be implemented to avert the collapse of fisheries1. (A report out this week from the World Economic Forum outlines other risks facing the world2). But for such applications to emerge, researchers should resist the lure of general rules. We must instead use all the available data to develop tools to study the specific properties of real systems.

 

Tipping points: From patterns to predictions

Carl Boettiger & Alan Hastings

Nature 493, 157–158 (10 January 2013) http://dx.doi.org/10.1038/493157a

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