Complexity Digest

Subscribe to Complexity Digest feed Complexity Digest
Networking the complexity community since 1999
Updated: 36 min 13 sec ago

Faculty Position in Statistical Physics of Complex Systems @EPFL

Tue, 10/22/2019 - 09:36

The School of Basic Sciences (Physics, Chemistry and Mathematics) at EPFL seeks to appoint a Professor in Statistical Physics of Complex Systems. This includes statistical physics of inference and learning, soft matter theory and theoretical biophysics. The appointment is offered at the Tenure Track Assistant Professor or tenured Associate Professor levels. We expect candidates to establish leadership and strengthen the EPFL endeavor in Statistical Physics of Complex Systems. Priority will be given to the overall originality and promise of the candidate’s work over any particular specialization area. Candidates should hold a PhD and have an excellent record of scientific accomplishments in the field. In addition, commitment to teaching at the undergraduate, master and doctoral levels is expected. Proficiency in French teaching is not required, but willingness to learn the language expected. EPFL, with its main campus located in Lausanne, Switzerland, on the shores of lake Geneva, is a dynamically growing and well-funded institution fostering excellence and diversity. It has a highly international campus with first-class infrastructure, including high performance computing As a technical university covering essentially the entire palette of engineering and science, EPFL offers a fertile environment for research cooperation between different disciplines. The EPFL environment is multi-lingual and multi-cultural, with English often serving as a common interface. Applications should include a cover letter, a CV with a list of publications, a concise statement of research (maximum 3 pages) and teaching interests (one page), and the names and addresses (including e-mail) of at least three references for a junior position or five references for a senior position. Applications should be uploaded (as PDFs) by November 15th, 2019 to https://facultyrecruiting.epfl.ch/position/18186240 Enquiries may be addressed to: Prof. Jan Hesthaven Dean of the School of Basic Sciences E-mail: fsbdean@epfl.ch Prof. Harald Brune Director of the Institute of Physics E-mail: IPHYSDirector@epfl.ch For additional information, please consult www.epfl.ch, sb.epfl.ch, iphys.epfl.ch EPFL is an equal opportunity employer and family friendly university. It is committed to increasing the diversity of its faculty. It strongly encourages women to Apply.

Source: www.epfl.ch

Melanie Mitchell’s ‘Artificial Intelligence’ exposes AI’s limits

Sun, 10/20/2019 - 15:53

Ever since its origin in post-war research, AI has been subject to profound hyperbole, rapturous prognostications, and projected nightmares. In 2019, things have once again reached fever pitch in what Science Board co-chair and External Professor Melanie Mitchell wryly notes is a hype cycle that routinely ripples through her fellow computer scientists and those who fund them. Her illuminating new book, Artificial Intelligence: A Guide for Thinking Humans, lays bare the inner workings of these potent tools, exposing their realistic limits and patiently detailing our deployment errors. It is a solid history of how we got from pocket calculators to facial recognition and self-driving cars, a lucid tour of how these systems operate, and a tempered read on just how far we have to go before we’re obsolete.

Source: www.santafe.edu

Pantheon

Fri, 10/18/2019 - 16:01

Pantheon is an observatory of human collective memory. With data on more than 70,000 biographies, Pantheon helps you explore the geography and dynamics of the most memorable people in our planet’s history.

Source: pantheon.world

Complex Networks: Theory, Methods, and Applications – Lake Como School of Advanced Studies – May 18-21, 2020

Wed, 10/16/2019 - 22:13

Many real systems can be modeled as networks, where the elements of the system are nodes and interactions between elements are edges. An even larger set of systems can be modeled using dynamical processes on networks, which are in turn affected by the dynamics. Networks thus represent the backbone of many complex systems, and their theoretical and computational analysis makes it possible to gain insights into numerous applications. Networks permeate almost every conceivable discipline—including sociology, transportation, economics and finance, biology, and myriad others—and the study of "network science" has thus become a crucial component of modern scientific education.

The school "Complex Networks: Theory, Methods, and Applications" offers a succinct education in network science. It is open to all aspiring scholars in any area of science or engineering who wish to study networks of any kind (whether theoretical or applied), and it is especially addressed to doctoral students and young postdoctoral scholars. The aim of the school is to deepen into both theoretical developments and applications in targeted fields.

LECTURERS
— REKA ALBERT, Pennsylvania State University
— GUIDO CALDARELLI, IMT Lucca
— MARTON KARSAI, Central European University
— JOSE FERNANDO MENDES, University of Aveiro
— NATASA PRZULJ, Barcelona Supercomputing Center

 

Spring School
COMPLEX NETWORKS: THEORY, METHODS, AND APPLICATIONS
(6th edition)

Lake Como School of Advanced Studies
Villa del Grumello, Como, Italy, 18-21 May 2020

Source: ntmf.lakecomoschool.org

11th International Conference on Complex Networks

Tue, 10/15/2019 - 10:17

 The International Conference on Complex Networks (CompleNet) brings together researchers and practitioners from diverse disciplines working on areas related to complex networks. In its 11th year, we are delighted to have the next CompleNet in Exeter UK hosted by the University of Exeter.

​Over the past two decades we have witnessed an exponential increase in the number of publications and research centers dedicated to this field. From biological systems to computer science, from technical to informational networks, from economic to social systems, complex networks are becoming pervasive for dozens of applications. It is the interdisciplinary nature of complex networks that CompleNet aims to capture and celebrate.

 

11th International Conference on Complex Networks
COMPLENET 2020
​31 March-3 April 2020
EXETER, UK

Source: complenet.weebly.com

The Prize in Economic Sciences 2019

Mon, 10/14/2019 - 08:44

The research conducted by this year’s Laureates has considerably improved our ability to fight global poverty. In just two decades, their new experiment-based approach has transformed development economics, which is now a flourishing field of research.

Despite recent dramatic improvements, one of humanity’s most urgent issues is the reduction of global poverty, in all its forms. More than 700 million people still subsist on extremely low incomes. Every year, around five million children under the age of five still die of diseases that could often have been prevented or cured with inexpensive treatments. Half of the world’s children still leave school without basic literacy and numeracy skills.

This year’s Laureates have introduced a new approach to obtaining reliable answers about the best ways to fight global poverty. In brief, it involves dividing this issue into smaller, more manageable, questions – for example, the most effective interventions for improving educational outcomes or child health. They have shown that these smaller, more precise, questions are often best answered via carefully designed experiments among the people who are most affected.

Source: www.nobelprize.org

Irreversibility and emergent structure in active matter

Thu, 10/10/2019 - 09:30

Active matter is rapidly becoming a key paradigm of out-of-equilibrium soft matter exhibiting complex collective phenomena, yet the thermodynamics of such systems remain poorly understood. In this article we study the dynamical irreversibility of large scale active systems capable of motility-induced phase separation and polar alignment. We use a model with momenta in both translational and rotational degrees of freedom, revealing a hidden component not previously reported in the literature. Steady state irreversibility is quantified at each point in the phase diagram which exhibits sharp discontinuities at phase transitions. Identification of the irreversibility in individual particles lays the groundwork for discussion of the thermodynamics of micro-features, such as defects in the emergent structure. The interpretation of the time reversal symmetry in the dynamics of the particles is found to be crucial.

 

Irreversibility and emergent structure in active matter
Phys. Rev. E
Emanuele Crosato, Mikhail Prokopenko, and Richard E. Spinney

Source: journals.aps.org

Scalar model of flocking dynamics on complex social networks

Wed, 10/09/2019 - 17:43

We investigate the effects of long-range social interactions in flocking dynamics by studying the dynamics of a scalar model of collective motion embedded in a complex network representing a pattern of social interactions, as observed in several social species. In this scalar model we find a phenomenology analogous to that observed in the classic Vicsek model: In networks with low heterogeneity, a phase transition separates an ordered from a disordered phase. At high levels of heterogeneity, instead, the transition is suppressed and the system is always ordered. This observation is backed up analytically by the solution of a modified scalar model within an heterogeneous mean-field approximation. Our work extends the understanding of the effects of social interactions in flocking dynamics and opens the path to the analytical study of more complex topologies of social ties.

 

Scalar model of flocking dynamics on complex social networks
M. Carmen Miguel, Romualdo Pastor-Satorras

Source: arxiv.org

U.S. Social Fragmentation at Multiple Scales

Wed, 10/09/2019 - 15:41

Despite global connectivity, societies seem to be increasingly polarized and fragmented. This phenomenon is rooted in the underlying complex structure and dynamics of social systems. Far from homogeneously mixing or adopting conforming views, individuals self-organize into groups at multiple scales, ranging from families up to cities and cultures. In this paper, we study the fragmented structure of the American society using mobility and communication networks obtained from geo-located social media data. We find self-organized patches with clear geographical borders that are consistent between physical and virtual spaces. The patches have multi-scale structure ranging from parts of a city up to the entire nation. Their significance is reflected in distinct patterns of collective interests and conversations. Finally, we explain the patch emergence by a model of network growth that combines mechanisms of geographical distance gravity, preferential attachment, and spatial growth. Our observations are consistent with the emergence of social groups whose separated association and communication reinforce distinct identities. Rather than eliminating borders, the virtual space reproduces them as people mirror their offline lives online. Understanding the mechanisms driving the emergence of fragmentation in hyper-connected social systems is imperative in the age of the Internet and globalization.

 

Leila Hedayatifar, Rachel A. Rigg, Yaneer Bar-Yam, and Alfredo J. Morales, U.S. social fragmentation at multiple scales, Journal of the Royal Society Interface (October 8, 2019).

Source: necsi.edu

The Nobel Prize in Chemistry 2019

Wed, 10/09/2019 - 08:36

The Nobel Prize in Chemistry 2019 rewards the development of the lithium-ion battery. This lightweight, rechargeable and powerful battery is now used in everything from mobile phones to laptops and electric vehicles. It can also store significant amounts of energy from solar and wind power, making possible a fossil fuel-free society.

Source: www.nobelprize.org

Anger while driving in Mexico City

Tue, 10/08/2019 - 11:42

This study aims to analyze the level of anger developed by drivers in Mexico City and also understand the behavior that those drivers use to express that anger, using four different survey methods. The first focuses on personal information, the second Driving Anger Expression Inventory (DAX), the third refers to a shorten version of Driving Anger Scale (DAS) and the fourth being the Dula Dangerous Driving Index (DDDI). These have previously been applied and validated in several different countries. The questionnaires were filled out online by 626 drivers. Using the data collected through the online platform, it was possible to identify the kind of reactions volunteers displayed while driving. Also, it was possible to identify that people in Mexico City developed anger depending on their driving area. Our analyses shows that in the Adaptive/Constructive Expression subscale, males and females show a significant difference in their mean score, with women express their anger in a more constructive way than males.

 

Hernández-Hernández AM, Siqueiros-García JM, Robles-Belmont E, Gershenson C (2019) Anger while driving in Mexico City. PLoS ONE 14(9): e0223048. https://doi.org/10.1371/journal.pone.0223048

Source: journals.plos.org

The Nobel Prize in Physics 2019

Tue, 10/08/2019 - 11:25

The Nobel Prize in Physics 2019 was awarded "for contributions to our understanding of the evolution of the universe and Earth’s place in the cosmos" with one half to James Peebles "for theoretical discoveries in physical cosmology", the other half jointly to Michel Mayor and Didier Queloz "for the discovery of an exoplanet orbiting a solar-type star."

Source: www.nobelprize.org

Chaos Scientist Finds Hidden Financial Risks That Regulators Miss

Tue, 10/08/2019 - 09:19

Today, in a more bucolic setting—the Institute for New Economic Thinking at the Oxford Martin School—Farmer is drawing on decades of complexity research that began with roulette. After winning acclaim as a pioneer of chaos theory, which helps explain the unpredictability of complex systems such as the weather, he jumped into markets, co-founding one of the early quantitative investment firms in the 1990s. Now, Farmer and a band of central bank researchers are focusing on the tangled web of global finance, using a tool of the natural sciences called agent-based models to find dangers lurking in the system and uncover ways to avoid them.

Source: www.bloomberg.com

Self-domesticated by violence to be peaceful. And violent

Mon, 10/07/2019 - 11:14

R Wrangham. The goodness paradox: How evolution made us both more and less violent. London, England: Profile Books, 2019, 400 pp., ISBN: 9781781255834 (hbk), £25.

In comparison to other species, humans are both surprisingly peaceful in their day-to-day interactions with unrelated conspecifics and unprecedently violent toward them when the situation requires it. A goodness paradox, as Wrangham (2019) dubs this strange relationship of humankind to violence, is the theme of his latest book attempting to comprise decades of research into a coherent theory of aggressive behavior focused on humans. Drawing on his expertise in primatology, Wrangham presents an evolutionary theory that not only expands contemporary thinking about human behavior but also challenges and refines several crucial notions of human evolution.

 

Self-domesticated by violence to be peaceful. And violent
Dan Řezníček

Adaptive Behavior

Source: journals.sagepub.com

The 2019 Nobel Prize in Physiology or Medicine 

Mon, 10/07/2019 - 08:59

Animals need oxygen for the conversion of food into useful energy. The fundamental importance of oxygen has been understood for centuries, but how cells adapt to changes in levels of oxygen has long been unknown.

William G. Kaelin Jr., Sir Peter J. Ratcliffe and Gregg L. Semenza discovered how cells can sense and adapt to changing oxygen availability. They identified molecular machinery that regulates the activity of genes in response to varying levels of oxygen.

The seminal discoveries by this year’s Nobel Laureates revealed the mechanism for one of life’s most essential adaptive processes. They established the basis for our understanding of how oxygen levels affect cellular metabolism and physiological function. Their discoveries have also paved the way for promising new strategies to fight anemia, cancer and many other diseases.

Source: www.nobelprize.org

Novelist Cormac McCarthy’s tips on how to write a great science paper

Sat, 10/05/2019 - 04:47

The Pulitzer prizewinner shares his advice for pleasing readers, editors and yourself.

Source: www.nature.com

Social Network Analysis for Social Neuroscientists

Fri, 10/04/2019 - 04:34

Although social neuroscience is concerned with understanding how the brain interacts with its social environment, prevailing research in the field has primarily considered the human brain in isolation, deprived of its rich social context. Emerging work in social neuroscience that leverages tools from network analysis has begun to pursue this issue, advancing knowledge of how the human brain influences and is influenced by the structures of its social environment. In this paper, we provide an overview of key theory and methods in network analysis (especially for social systems) as an introduction for social neuroscientists who are interested in relating individual cognition to the structures of an individual’s social environments. We also highlight some exciting new work as examples of how to productively use these tools to investigate questions of relevance to social neuroscientists. We include tutorials to help with practical implementation of the concepts that we discuss. We conclude by highlighting the broad range of exciting research opportunities for social neuroscientists who are interested in using network analysis to study social systems.

 

Baek, Elisa, Mason A. Porter, and Carolyn Parkinson. 2019. “Social Network Analysis for Social Neuroscientists.” PsyArXiv. September 26. doi:10.31234/osf.io/kgc2h.

Source: psyarxiv.com

To find the best parking spot, do the math

Thu, 10/03/2019 - 04:19

The next time you’re hunting for a parking spot, mathematics could help you identify the most efficient strategy, according to a recent paper in the Journal of Statistical Mechanics. It’s basically an optimization problem: weighing different variables and crunching the numbers to find the optimal combination of those factors. In the case of where to put your car, the goal is to strike the optimal balance of parking close to the target—a building entrance, for example—without having to waste too much time circling the lot hunting for the closest space.

Source: arstechnica.com

Measuring complexity

Wed, 10/02/2019 - 22:37

Complexity is heterogenous, involving nonlinearity, self-organisation, diversity, adaptive behaviour, among other things. It is therefore obviously worth asking whether purported measures of complexity measure aggregate phenomena, or individual aspects of complexity and if so which. This paper uses a recently developed rigorous framework for understanding complexity to answer this question about measurement. The approach is two-fold: find measures of individual aspects of complexity on the one hand, and explain measures of complexity on the other. We illustrate the conceptual framework of complexity science and how it links the foundations to the practised science with examples from different scientific fields and of various aspects of complexity. Furthermore, we analyse a selection of purported measures of complexity that have found wide application and explain why and how they measure aspects of complexity. This work gives the reader a tool to take any existing measure of complexity and analyse it, and to take any feature of complexity and find the right measure for it.

 

Measuring complexity

Karoline Wiesner, James Ladyman

Source: arxiv.org

Collective Irrationality and Positive Feedback

Wed, 10/02/2019 - 16:32

Recent experiments on ants and slime moulds have assessed the degree to which they make rational decisions when presented with a number of alternative food sources or shelter. Ants and slime moulds are just two examples of a wide range of species and biological processes that use positive feedback mechanisms to reach decisions. Here we use a generic, experimentally validated model of positive feedback between group members to show that the probability of taking the best of options depends crucially on the strength of feedback. We show how the probability of choosing the best option can be maximized by applying an optimal feedback strength. Importantly, this optimal value depends on the number of options, so that when we change the number of options the preference of the group changes, producing apparent “irrationalities”. We thus reinterpret the idea that collectives show "rational" or "irrational" preferences as being a necessary consequence of the use of positive feedback. We argue that positive feedback is a heuristic which often produces fast and accurate group decision-making, but is always susceptible to apparent irrationality when studied under particular experimental conditions.

 

Nicolis SC, Zabzina N, Latty T, Sumpter DJT (2011) Collective Irrationality and Positive Feedback. PLoS ONE 6(4): e18901. https://doi.org/10.1371/journal.pone.0018901

Source: journals.plos.org

Pages