🚗🚌 http://nautil.us/issue/71/flow/why-a-traffic-flow-suddenly-turns-into-a-traffic-jam

🎞 State-Space Compression, Coarse-Graining, and the Averaging of Life and Mind

Simon DeDeo

Abstract
Renormalization is a principled coarse-graining of space-time. It shows us how the small-scale details of a system may become irrelevant when looking at larger scales and lower energies. Coarse-graining is also crucial, however, for biological and cultural systems that lack a natural spatial arrangement. I introduce the notion of coarse-graining and equivalence classes, and give a brief history of attempts to tame the problem of simplifying and "averaging" things as various as algorithms and languages. I then present state-space compression, a new framework for understanding the general problem. At the end, I present recent empirical results, in an animal social system, that show evidence for the coupling of scales: the reaction of coarse-grained facts about a system "downwards" to influence the microphysics.


🔗 http://www.perimeterinstitute.ca/videos/state-space-compression-coarse-graining-and-averaging-life-and-mind

💡 Coarse-Graining

In physics a fine-grained description of a system is a detailed description of its microscopic behavior. A coarse-grained description is one in which some of this fine detail has been smoothed over.

Coarse-graining is at the core of the second law of thermodynamics, which states that the entropy of the universe is increasing. As entropy, or randomness, increases there is a loss of structure. This simply means that some of the information we originally had about the system has become no longer useful for making predictions about the behavior of a system as a whole. To make this more concrete, think about temperature.

Temperature is the average speed of particles in a system. Temperature is a coarse-grained representation of all of the particles’ behavior–the particles in aggregate. When we know the temperature we can use it to predict the system’s future state better than we could if we actually measured the speed of individual particles. This is why coarse-graining is so important–it is incredibly useful. It gives us what is called an effective theory. An effective theory allows us to model the behavior of a system without specifying all of the underlying causes that lead to system state changes.

It is important to recognize that a critical property of a coarse-grained description is that it is “true” to the system, meaning that it is a reduction or simplification of the actual microscopic details. When we give a coarse-grained description we do not introduce any outside information. We do not add anything that isn’t already in the details. This “lossy but true” property is one factor that distinguishes coarse-graining from other types of abstraction.

A second property of coarse-graining is that it involves integrating over component behavior. An average is a simple example but more complicated computations are also possible.

Normally when we talk of coarse-graining, we mean coarse-grainings that we as scientists impose on the system to find compact descriptions of system behavior sufficient for good prediction. In other words, coarse-graining helps the scientist identify the relevant regularities for explaining system behavior.

However, we can also ask how adaptive systems identify (in evolutionary, developmental, or learning time) regularities and build effective theories to guide decision making and behavior. Coarse-graining is one kind of inference mechanism that adaptive systems can use to build effective theories. To distinguish coarse-graining in nature from coarse-graining by scientists, we refer to coarse-graining in nature as endogenous coarse-graining.

Because adaptive systems are imperfect information processors, coarse-graining in nature is unlikely to be a perfect or “true” simplification of the microscopic details as it is the physics sense. It is also worth noting that coarse-graining in nature is complicated by the fact that in adaptive systems it is often a collective process performed by a large number of semi-independent components. One of many interesting questions is whether the subjectivity and error inherent in biological information processing can be overcome through collective coarse-graining. 

In my view two key questions for 21st-century biology are how nature coarse-grains and how the capacity for coarse-graining influences the quality of the effective theories that adaptive systems build to make predictions. Answering these questions might help us gain traction on some traditionally quite slippery philosophical questions. Among these, is downward causation “real” and are biological systems law-like?

🎞 Fields Medal winner (2010) Cédric Villani gives a talk devoted to the presentation of some of the most important concepts in statistical mechanics, including Boltzmann's statistical entropy, the notion of macroscopic irreversibility and molecular chaos, and the Boltzmann equation.

https://www.youtube.com/watch?v=u3zU3HLQWf8

🎞 https://www.youtube.com/watch?v=lwW-5fIKaxg

#سمینارهای_هفتگی
مرکز شبکه‌های پیچیده و علم‌داده اجتماعی دانشگاه شهید بهشتی (CCNSD)

🗣 محمد شرافتی - دانشگاه شهیدبهشتی

⏰ دوشنبه، ۹ اردیبهشت ساعت ۱۶:۰۰
🏛 محل برگزاری: سالن ابن‌هیثم


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⭕️ مشتاق دیدار همه اقشار جامعه در مرکز هستیم. برای هماهنگی‌ با مسئول جلسه‌ می‌توانید با آقای محمد شرافتی ‌تماس بگیرید:‍‍‍‍
📞 @herman1

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🕸 مرکز شبکه‌های پیچیده و علم داده اجتماعی دانشگاه شهید بهشتی

🕸 @CCNSD 🔗 ccnsd.ir
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💠 آغاز ثبت‌نام در سمینار مغز و علوم شناختی

🕰 سه‌شنبه ۱۰ اردیبهشت
ساعت ۱۳:۳۰ الی ۱۸
چهارشنبه ۱۱ اردیبهشت
ساعت ۱۰ الی ۱۸
🏛 سالن آمفی‌تئاتر دانشکده مهندسی انرژی دانشگاه شریف

🌐 ثبت‌نام در evnd.co/jCktA


#BrainAwarenessWeek
@Shenasa_Sharif
@anjoman_elmi_phys_sut

✅ In this paper "Testing statistical laws in complex systems" they have revisitef the controversy #power_laws, showing that correlations are responsible for many of the recent (false) rejections.

PRL version: https://t.co/DmdzPycEFi arXiv version: https://t.co/6227uYYBpt

🚨 https://comdig.unam.mx/2019/04/27/the-stochastic-thermodynamics-of-computation/

https://t.co/PwiBHp5SxW via #IOPscience

🎞 Paul Andersen explains the concepts of genetics. He starts with a brief discussion of the nature vs. nurture debate and shows how epigenetics blurs this distinction. He explains how differentiation of cell types results from the inactivation of certain genes. He describes the three processes of epigenetics: DNA methylation, Histone acteylation and microRNA.

https://www.youtube.com/watch?v=i9a-ru2ES6Y

#سمینار_عمومی این هفته
Some idea from social science to study Gene-Gene Interactions of the Cancerous Cells

- سه‌شنبه ۱۰ اردیبهشت؛ ساعت ۱۵:۳۰ الی ۱۶:۳۰
- تالار ابن هیثم، دانشکده‌ فیزیک

کانال انجمن علمی فیزیک بهشتی
@sbu_physics

🧠 https://www.nature.com/articles/d41586-019-00687-9

Geometric renormalization unravels self-similarity of the multiscale human connectome
“structure of the human brain remains self-similar when the resolution length is progressively decreased by hierarchical coarse-graining of the anatomical regions”

https://t.co/YEIjyWNoYd

⏰ برنامه زمان‌بندی و عناوین ارائه‌ها
🔺سمینار “مغز و علوم شناختی”
🏛سالن آمفی‌تئاتر دانشکده انرژی


🌟همراه با پنل فلسفه، هوش مصنوعی و علوم شناختی
دانشجویان فلسفه علم و مهندسی کامپیوتر
⭐ابوطالب صفدری و امیرحسین حاجی شمسایی

🔗لینک ثبت‌نام:
evnd.co/jCktA

#BrainAwarenessWeek
@Shenasa_Sharif

📢 Joint European Thermodynamics Conference (JETC2019)
⏰ 21–24 May 2019
📍 Barcelona, Spain
https://t.co/fBg0o4medy

Welcome to submit to joint #SpecialIssue with JETC2019.

https://t.co/PIS9TXhP8D

🌍 https://www.futurity.org/power-law-exponent-2049012-2/

“For 100 years, people have been talking about one kind of #powerlaw distribution...now, we’re documenting these discrete scales. Instead of a smooth curve, our power law looks like an infinite staircase.”

New research
https://t.co/H9hQ4pXr4G