Complex Systems Studies – Telegram
Complex Systems Studies
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What's up in Complexity Science?!
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#complexity #complex_systems #networks #network_science

📨 Contact us: @carimi
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David Tong: Lectures on Statistical Field Theory

These lecture notes provide a detailed introduction to phase transitions and the renormalisation group, aimed at "Part III" (i.e. masters level) students. The lecture notes come in around 130 pages and can be downloaded below.

http://www.damtp.cam.ac.uk/user/tong/sft.html
Modeling cities
“short review with a discussion about the possibility of constructing a science of cities”

https://t.co/4M5Sga7q4s
🎞 Is Complexity a Science? Is it a possibly useful new way of engineering?

In this video narrated by Maxi San Miguel it will be argued that Complexity is a new way of thinking, necessary for a scientific renaissance that can transform society.

📺 https://t.co/OR41RZjRCd
geoplot looks like a nice tool for plotting geo data in Python. Seaborn but for spatial data ;) You can try there quick start tutorial here: https://t.co/2JjhfsvFBV
no install needed
🖤 Recollecting Mitchell Feigenbaum— a chaos pioneer

by SFI External Professor Fred Cooper

https://medium.com/@sfiscience/recollecting-mitchell-feigenbaum-a-chaos-pioneer-206a73a91a42

Feigenbaum’s constants are universal ratios … that relate to phenomena with oscillatory (cyclic) behavior, such as swinging pendulums or heart rhythms. The most well-known one, Feigenbaum’s Delta, refers to the spacing between parameter values required to double the cycle’s length, which decreases exponentially by a factor approaching approximately 4.669.

Among all my friends, Mitchell was the most unusual and brilliant. He viewed the world through the lens of a scientist. When he walked through the forest he wondered “at what distance do the trees merge and become inseparable?” When he looked at the moon he wondered “why does the moon appear larger when it is on the horizon?” He then needed to develop a theory to explain these phenomena “from scratch.” This led him to study how vision evolved from fish to humans and why optical illusions occur as a result of “mistakes” made by our sensory cognition. When he was asked by Pete Carruthers, “what is the origin of turbulence?” Mitchell looked at the simplest nonlinear system — the logistic map where bifurcations took place. This led to the famous Feigenbaum numbers, which were an essential part in understanding the onset of chaos.

Mitchell had a great love of music and again wondered how can one improve on digital technology so that the sound of the onset of a bow string could be captured. His interest in photography led him to write computer codes to undo the mistakes made by existing copying machines so that a perfect image could be printed. I found it fascinating that not only did he ask these questions, which were unusual to me, but then he dropped everything to figure out the answer. This also led to the production of maps with minimal distortion and computer codes for figuring out how to label maps in the clearest fashion.

Mitchell was a dear friend and he will be missed.
Spectral properties and the accuracy of mean-field approaches for epidemics on correlated networks
“comparison between stochastic simulations and mean-field theories of the susceptible-infected-susceptible (SIS) model on correlated networks”

https://t.co/h6h6o7KPqy
Calling all quantitative life scientists! Deadline to apply to this postdoc is July 10, 2019!

https://t.co/1utmJVxueR
terrific paper on causal emergence: https://t.co/ZNBVvq0dhy

Since then, we’ve been building a formalism to study causal emergence in networks. Today we posted our first paper on it https://t.co/Til7g7LCEk
Complex Systems Studies
terrific paper on causal emergence: https://t.co/ZNBVvq0dhy Since then, we’ve been building a formalism to study causal emergence in networks. Today we posted our first paper on it https://t.co/Til7g7LCEk
Networks are such powerful objects. They've changed how we study complex systems. But I’ve always been struck by how nontrivial the “what is a node?” question can be.

We provide a framework for identifying the most informative *scale* to describe interdependencies in a system...
Complex Systems Studies
Networks are such powerful objects. They've changed how we study complex systems. But I’ve always been struck by how nontrivial the “what is a node?” question can be. We provide a framework for identifying the most informative *scale* to describe interdependencies…
...which is to say, we find that compressed or coarse-grained or macroscale denoscriptions of networks often have more *effective information* than the original microscale network (e.g. your raw network data).

This noise-minimizing process is known as causal emergence.

So what?
Complex Systems Studies
...which is to say, we find that compressed or coarse-grained or macroscale denoscriptions of networks often have more *effective information* than the original microscale network (e.g. your raw network data). This noise-minimizing process is known as causal…
It's a question of zoom: what's the right scale to represent brain networks, given what we want from our model? What's the best scale to model economic systems? What counts as a "node" in a genome?

They're rich, tough, fun problems. And there's a long way to go.
What are the gender differences in scientific productivity and impact?

We reconstructed 1.5 million careers with fascinating findings at
https://t.co/5VuiWpxXxo.

1. Paradoxically, as the fraction of women has increased in academia, so did the productivity and impact gender gaps.

2. The good news: there are no systematic differences between the annual productivity of male and female scientists! Annual productivity is a key gender-invariant.

3. There is, however, a persistent higher dropout rate for women at all stages of their careers.

4. Once we correct for the different dropout rate, the productivity and the impact differences between female and male scientists are reduced by roughly two-thirds.

5. We also discover a second gender invariant quantity: men and women have equivalent career-wise impact for the same size body of work (total number of publications).

The bottom line:
https://twitter.com/barabasi/status/1149210323724984321?s=19
Forwarded from Complex Networks (SBU)
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‍~~~~~~~~~~~~~~~~
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In July’s issue of Nature Machine Intelligence, find out about machine intelligence in drug discovery, an approach for automatic classification of answers in free-form surveys and whether AI will soon surpass humans in playing Angry Birds!

https://go.nature.com/2S4N24P
💡 Statistical mechanics of time series.

https://arxiv.org/abs/1907.04925

Countless natural and social multivariate systems are studied through sets of simultaneous and time-spaced measurements of the observables that drive their dynamics, i.e., through sets of time series. Typically, this is done via hypothesis testing: the statistical properties of the empirical time series are tested against those expected under a suitable null hypothesis. This is a very challenging task in complex interacting systems, where statistical stability is often poor due to lack of stationarity and ergodicity. Here, we describe an unsupervised, data-driven framework to perform hypothesis testing in such situations. This consists of a statistical mechanical theory - derived from first principles - for ensembles of time series designed to preserve, on average, some of the statistical properties observed on an empirical set of time series. We showcase its possible applications on a set of stock market returns from the NYSE.