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Chaos | The Great Courses

Complexity Digest - 11 hours 19 min ago

It has been called the third great revolution of 20th-century physics, after relativity and quantum theory. But how can something called chaos theory help you understand an orderly world? What practical things might it be good for? What, in fact, is chaos theory? "Chaos theory," according to Dr. Steven Strogatz, Director of the Center for Applied Mathematics at Cornell University, "is the science of how things change." It describes the behavior of any system whose state evolves over time and whose behavior is sensitive to small changes in its initial conditions.

Source: www.thegreatcourses.com

Metrics of Emergence, Self-Organization, and Complexity for EWOM Research

Complexity Digest - 12 hours 1 min ago

Juan C. Correa

Front. Phys., 21 February 2020


In a recent round table organized by the Santa Fe Institute, the complexity of commerce captured the attention of those interested in understanding how complex systems science can be applicable for settings where consumers and providers interact. Despite the usefulness of applied complexity for commerce-related phenomena, few works have attempted to provide insightful ideas. This mini-review aims at providing a succinct discussion of how the metrics of emergence, self-organization, and complexity might benefit the research agenda of applied complexity and commerce/consumer studies. In particular, the paper argues possible pragmatic ways to understanding the valuable information present in word-of-mouth data found on electronic commerce platforms.

Source: www.frontiersin.org

Tesco Grocery 1.0, a large-scale dataset of grocery purchases in London

Complexity Digest - Thu, 02/20/2020 - 14:11

Luca Maria Aiello, Daniele Quercia, Rossano Schifanella & Lucia Del Prete 
Scientific Data volume 7, Article number: 57 (2020)


We present the Tesco Grocery 1.0 dataset: a record of 420 M food items purchased by 1.6 M fidelity card owners who shopped at the 411 Tesco stores in Greater London over the course of the entire year of 2015, aggregated at the level of census areas to preserve anonymity. For each area, we report the number of transactions and nutritional properties of the typical food item bought including the average caloric intake and the composition of nutrients. The set of global trade international numbers (barcodes) for each food type is also included. To establish data validity we: i) compare food purchase volumes to population from census to assess representativeness, and ii) match nutrient and energy intake to official statistics of food-related illnesses to appraise the extent to which the dataset is ecologically valid. Given its unprecedented scale and geographic granularity, the data can be used to link food purchases to a number of geographically-salient indicators, which enables studies on health outcomes, cultural aspects, and economic factors.

Source: www.nature.com

The role of worldviews in the governance of sustainable mobility

Complexity Digest - Thu, 02/20/2020 - 09:39

Frank Chuang, Ed Manley, Arthur Petersen



In sustainability policy-making, a critical task is to value present and future needs in order to realize good quality of life. To analyze complex ideas of how people interpret reality, develop value orientations, and define needs and the good life, the notion of worldviews proved to be useful. We use worldviews to study how people of distinct ways of life perceive and assess sustainable mobility issues. Through exploring three worldviews (egalitarianism, hierarchy, and individualism), our results map across British people’s attitudes to mobility debates in terms of the economic, environmental, social, and political dimensions. In so doing, our study demonstrates a framework for identifying what behavioral and institutional barriers hinder the transformations needed to achieve better cities and societies.

Source: www.pnas.org

What Differs Us From Machines?

Complexity Digest - Thu, 02/20/2020 - 08:49

Carlos Gershenson


One of the most amazing things about reading R.U.R. a century after it was first published is noticing how many questions underlying the story are still current. It is worth noting that Čapek’s robots are not mechanical, but living. In this sense, they are closer to artificial life than to artificial intelligence. One has to consider that the play was staged before the first electronic computers were built and before DNA was discovered (no mobile phones, no commercial aviation, no Internet). We still do not have agreed definitions of life nor intelligence, imagine how ambiguous these should have been a century ago.

Source: papers.ssrn.com

From language shift to language revitalization and sustainability. Albert Bastardas-Boada.

Complexity Digest - Tue, 02/18/2020 - 14:58

This book aims to contribute to the overall, integrated understanding of the processes of language contact and their evolution, be they the result of political or economic (dis)integrations or migrations or for technological reasons. Via an interdisciplinary, holistic approach, it also aims to support the theoretical grounding of a unified, common sociolinguistic paradigm, based on an ecological and complexity perspective. This approach built on the fact that linguistic structures do not live in isolation from their social functions and must be situated in relation to the sub-and supra-systems that determine their existence if we are to understand their fortunes. It is a useful contribution to understanding and promoting the processes of linguistic revitalization in the world, combining at the same time the maintenance and development of diversity while ensuring the intercommunication of human species.

Source: www.publicacions.ub.edu

Evolution in the Debian GNU/Linux software network: analogies and differences with gene regulatory networks

Complexity Digest - Mon, 02/17/2020 - 17:04

Pablo Villegas, Miguel A. Muñoz and Juan A. Bonachela

Journal of The Royal Society Interface Volume 17 Issue 163


Biological networks exhibit intricate architectures deemed to be crucial for their functionality. In particular, gene regulatory networks, which play a key role in information processing in the cell, display non-trivial architectural features such as scale-free degree distributions, high modularity and low average distance between connected genes. Such networks result from complex evolutionary and adaptive processes difficult to track down empirically. On the other hand, there exists detailed information on the developmental (or evolutionary) stages of open-software networks that result from self-organized growth across versions. Here, we study the evolution of the Debian GNU/Linux software network, focusing on the changes of key structural and statistical features over time. Our results show that evolution has led to a network structure in which the out-degree distribution is scale-free and the in-degree distribution is a stretched exponential. In addition, while modularity, directionality of information flow, and average distance between elements grew, vulnerability decreased over time. These features resemble closely those currently shown by gene regulatory networks, suggesting the existence of common adaptive pathways for the architectural design of information-processing networks. Differences in other hierarchical aspects point to system-specific solutions to similar evolutionary challenges.

Source: royalsocietypublishing.org

The effect of travel restrictions on the spread of the 2019 novel coronavirus (2019-nCoV) outbreak

Complexity Digest - Sun, 02/16/2020 - 10:14

Matteo Chinazzi, Jessica T. Davis, Marco Ajelli, Corrado Gioannini, Maria Litvinova, Stefano Merler, View ORCID ProfileAna Pastore y Piontti, Luca Rossi, Kaiyuan Sun, Cécile Viboud, Xinyue Xiong, Hongjie Yu, M. Elizabeth Halloran, Ira M. Longini Jr., Alessandro Vespignani


Motivated by the rapid spread of a novel coronavirus (2019-nCoV) in Mainland China, we use a global metapopulation disease transmission model to project the impact of both domestic and international travel limitations on the national and international spread of the epidemic. The model is calibrated on the evidence of internationally imported cases before the implementation of the travel quarantine of Wuhan. By assuming a generation time of 7.5 days, the reproduction number is estimated to be 2.4 [90% CI 2.2-2.6]. The median estimate for number of cases before the travel ban implementation on January 23, 2020 is 58,956 [90% CI 40,759 – 87,471] in Wuhan and 3,491 [90% CI 1,924 – 7,360] in other locations in Mainland China. The model shows that as of January 23, most Chinese cities had already received a considerable number of infected cases, and the travel quarantine delays the overall epidemic progression by only 3 to 5 days. The travel quarantine has a more marked effect at the international scale, where we estimate the number of case importations to be reduced by 80% until the end of February. Modeling results also indicate that sustained 90% travel restrictions to and from Mainland China only modestly affect the epidemic trajectory unless combined with a 50% or higher reduction of transmission in the community.

Source: www.medrxiv.org

How social and physical technologies collaborate to create

Complexity Digest - Sun, 02/16/2020 - 09:47

Doyne Farmer, Fotini Markopoulou, Eric Beinhocker & Steen Rasmussen


Our world is a system, in which physical and social technologies co-evolve. How can we shape a process we don’t control?

Source: aeon.co

Global ecosystem thresholds driven by aridity

Complexity Digest - Sat, 02/15/2020 - 10:26

Aridity, which is increasing worldwide because of climate change, affects the structure and functioning of dryland ecosystems. Whether aridification leads to gradual (versus abrupt) and systemic (versus specific) ecosystem changes is largely unknown. We investigated how 20 structural and functional ecosystem attributes respond to aridity in global drylands. Aridification led to systemic and abrupt changes in multiple ecosystem attributes. These changes occurred sequentially in three phases characterized by abrupt decays in plant productivity, soil fertility, and plant cover and richness at aridity values of 0.54, 0.7, and 0.8, respectively. More than 20% of the terrestrial surface will cross one or several of these thresholds by 2100, which calls for immediate actions to minimize the negative impacts of aridification on essential ecosystem services for the more than 2 billion people living in drylands.

Source: science.sciencemag.org

Language Evolution in Swarm Robotics: A Perspective

Complexity Digest - Fri, 02/14/2020 - 13:12

Nicolas Cambier, Roman Miletitch, Vincent Frémont, Marco Dorigo, Eliseo Ferrante and Vito Trianni


While direct local communication is very important for the organization of robot swarms, so far it has mostly been used for relatively simple tasks such as signaling robots preferences or states. Inspired by the emergence of meaning found in natural languages, more complex communication skills could allow robot swarms to tackle novel situations in ways that may not be a priori obvious to the experimenter. This would pave the way for the design of robot swarms with higher autonomy and adaptivity. The state of the art regarding the emergence of communication for robot swarms has mostly focused on offline evolutionary approaches, which showed that signaling and communication can emerge spontaneously even when not explicitly promoted. However, these approaches do not lead to complex, language-like communication skills, and signals are tightly linked to environmental and/or sensory-motor states that are specific to the task for which communication was evolved. To move beyond current practice, we advocate an approach to emergent communication in robot swarms based on language games. Thanks to language games, previous studies showed that cultural self-organization—rather than biological evolution—can be responsible for the complexity and expressive power of language. We suggest that swarm robotics can be an ideal test-bed to advance research on the emergence of language-like communication. The latter can be key to provide robot swarms with additional skills to support self-organization and adaptivity, enabling the design of more complex collective behaviors.

Source: www.frontiersin.org

CCS2020: Conference on Complex Systems. Palma de Mallorca, Oct 19-23

Complexity Digest - Fri, 02/14/2020 - 10:22

Complexity, understood as the emergence of new macro properties from the interactions of basic components, is a pervasive characteristic in natural, artificial and social systems. The Conference on Complex Systems (CCS) is the biggest and most important annual meeting of the international complex systems community. It comes under the auspices of the Complex Systems Society. This edition, after successful events in Singapore , Thessaloniki (Greece) , Cancun (Mexico) and Amsterdam (Netherlands), will take place in the Mediterranean island of Mallorca, Spain, organized by IFISC (CSIC-UIB).

Source: ccs2020.org

Self-reported willingness to share political news articles in online surveys correlates with actual sharing on Twitter

Complexity Digest - Thu, 02/13/2020 - 09:26

Mohsen Mosleh, Gordon Pennycook, David G. Rand 


There is an increasing imperative for psychologists and other behavioral scientists to understand how people behave on social media. However, it is often very difficult to execute experimental research on actual social media platforms, or to link survey responses to online behavior in order to perform correlational analyses. Thus, there is a natural desire to use self-reported behavioral intentions in standard survey studies to gain insight into online behavior. But are such hypothetical responses hopelessly disconnected from actual sharing decisions? Or are online survey samples via sources such as Amazon Mechanical Turk (MTurk) so different from the average social media user that the survey responses of one group give little insight into the on-platform behavior of the other? Here we investigate these issues by examining 67 pieces of political news content. We evaluate whether there is a meaningful relationship between (i) the level of sharing (tweets and retweets) of a given piece of content on Twitter, and (ii) the extent to which individuals (total N = 993) in online surveys on MTurk reported being willing to share that same piece of content. We found that the same news headlines that were more likely to be hypothetically shared on MTurk were also shared more frequently by Twitter users, r = .44. For example, across the observed range of MTurk sharing fractions, a 20 percentage point increase in the fraction of MTurk participants who reported being willing to share a news headline on social media was associated with 10x as many actual shares on Twitter. We also found that the correlation between sharing and various features of the headline was similar using both MTurk and Twitter data. These findings suggest that self-reported sharing intentions collected in online surveys are likely to provide some meaningful insight into what content would actually be shared on social media.

Source: journals.plos.org

Adoption Dynamics and Societal Impact of AI Systems in Complex Networks 

Complexity Digest - Wed, 02/12/2020 - 15:03

Pedro M. Fernandes, Francisco C. Santos, Manuel Lopes

AIES ’20: Proceedings of the AAAI/ACM Conference on AI, Ethics, and SocietyFebruary 2020 Pages 258–264


We propose a game-theoretical model to simulate the dynamics of AI adoption in adaptive networks. This formalism allows us to understand the impact of the adoption of AI systems for society as a whole, addressing some of the concerns on the need for regulation. Using this model we study the adoption of AI systems, the distribution of the different types of AI (from selfish to utilitarian), the appearance of clusters of specific AI types, and the impact on the fitness of each individual. We suggest that the entangled evolution of individual strategy and network structure constitutes a key mechanism for the sustainability of utilitarian and human-conscious AI. Differently, in the absence of rewiring, a minority of the population can easily foster the adoption of selfish AI and gains a benefit at the expense of the remaining majority.

Source: dl.acm.org

Artificial Life—Next Generation Perspectives: Echoes from the 2018 Conference in Tokyo

Complexity Digest - Wed, 02/12/2020 - 12:57

Olaf Witkowski, Takashi Ikegami, Nathaniel Virgo, Mizuki Oka and Hiroyuki Iizuka


Artificial life is a research field devoted to the theoretical study of features of living systems, such as evolution and the brain. The field has developed philosophical concepts such as autopoiesis and emergence, alongside a large range of computational and experimental setups, from evolutionary simulations to robotics and chemical experiments.

The complexity and diversity of the artificial life field is crucial to its community. Many researchers consider the community as a real source of creativity and free-minded exchange of ideas on important questions. For ideas that donʼt fit neatly into a single “mainstream” field of science, there is value in examining and discussing them in a context free from departmental or disciplinary constraints, with the purpose of reaching a better knowledge of the fundamental mechanisms that govern living systems.

Source: www.mitpressjournals.org

Ecosystem antifragility: beyond integrity and resilience

Complexity Digest - Tue, 02/11/2020 - 06:34

We review the concept of ecosystem resilience in its relation to ecosystem integrity from an information theory approach. We summarize the literature on the subject identifying three main narratives: ecosystem properties that enable them to be more resilient; ecosystem response to perturbations; and complexity. We also include original ideas with theoretical and quantitative developments with application examples. The main contribution is a new way to rethink resilience, that is mathematically formal and easy to evaluate heuristically in real-world applications: ecosystem antifragility. An ecosystem is antifragile if it benefits from environmental variability. Antifragility therefore goes beyond robustness or resilience because while resilient/robust systems are merely perturbation-resistant, antifragile structures


Equihua M, Espinosa Aldama M, Gershenson C, López-Corona O, Munguía M, Pérez-Maqueo O, Ramírez-Carrillo E. 2020. Ecosystem antifragility: beyond integrity and resilience. PeerJ 8:e8533 https://doi.org/10.7717/peerj.8533

Source: peerj.com

Dynamics of a birth–death process based on combinatorial innovation

Complexity Digest - Mon, 02/10/2020 - 15:20

Mike Steel, Wim Hordijk, Stuart A. Kauffman

Journal of Theoretical Biology


A feature of human creativity is the ability to take a subset of existing items (e.g. objects, ideas, or techniques) and combine them in various ways to give rise to new items, which, in turn, fuel further growth. Occasionally, some of these items may also disappear (extinction). We model this process by a simple stochastic birth–death model, with non-linear combinatorial terms in the growth coefficients to capture the propensity of subsets of items to give rise to new items. In its simplest form, this model involves just two parameters (P, α). This process exhibits a characteristic ‘hockey-stick’ behaviour: a long period of relatively little growth followed by a relatively sudden ‘explosive’ increase. We provide exact expressions for the mean and variance of this time to explosion and compare the results with simulations. We then generalise our results to allow for more general parameter assignments, and consider possible applications to data involving human productivity and creativity.


Source: www.sciencedirect.com

Climate risk and response

Complexity Digest - Mon, 02/10/2020 - 11:19

How could Earth’s changing climate impact socioeconomic systems across the world in the next three decades? A yearlong, cross-disciplinary research effort at McKinsey & Company provides some answers.

Source: www.mckinsey.com

Science of Stories

Complexity Digest - Sun, 02/09/2020 - 15:30

Stories have the power to shape our identities and worldviews. They can be factual or fictional, text-based or visual and can take many forms—from novels and non-fiction to conspiracy theories, rumors and disinformation. This Collection includes primary research papers that propose innovative, data-driven approaches to understanding stories and their impact, on such topics as the nature of narrative and narrative thinking, methods to extract stories from datasets and datasets from stories, the role of narrative in science communication, and the transformative power of stories.

Source: collections.plos.org

Friendship paradox biases perceptions in directed networks

Complexity Digest - Fri, 02/07/2020 - 14:35

Nazanin Alipourfard, Buddhika Nettasinghe, Andrés Abeliuk, Vikram Krishnamurthy & Kristina Lerman 
Nature Communications volume 11, Article number: 707 (2020)


Social networks shape perceptions by exposing people to the actions and opinions of their peers. However, the perceived popularity of a trait or an opinion may be very different from its actual popularity. We attribute this perception bias to friendship paradox and identify conditions under which it appears. We validate the findings empirically using Twitter data. Within posts made by users in our sample, we identify topics that appear more often within users’ social feeds than they do globally among all posts. We also present a polling algorithm that leverages the friendship paradox to obtain a statistically efficient estimate of a topic’s global prevalence from biased individual perceptions. We characterize the polling estimate and validate it through synthetic polling experiments on Twitter data. Our paper elucidates the non-intuitive ways in which the structure of directed networks can distort perceptions and presents approaches to mitigate this bias.

Source: www.nature.com


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