Bookmark | Chris Aldrich

🔖 Upcoming Special Issue “Information Theory in Neuroscience” | Entropy (MDPI)

Bookmarked Special Issue "Information Theory in Neuroscience" (Entropy | MDPI)

As the ultimate information processing device, the brain naturally lends itself to be studied with information theory. Application of information theory to neuroscience has spurred the development of principled theories of brain function, has led to advances in the study of consciousness, and to the development of analytical techniques to crack the neural code, that is to unveil the language used by neurons to encode and process information. In particular, advances in experimental techniques enabling precise recording and manipulation of neural activity on a large scale now enable for the first time the precise formulation and the quantitative test of hypotheses about how the brain encodes and transmits across areas the information used for specific functions. This Special Issue emphasizes contributions on novel approaches in neuroscience using information theory, and on the development of new information theoretic results inspired by problems in neuroscience. Research work at the interface of neuroscience, Information Theory and other disciplines is also welcome. A special issue of Entropy (ISSN 1099-4300). This special issue belongs to the section "Information Theory". Deadline for manuscript submissions: 1 December 2017

🔖 Back to the Future: The Decentralized Web, a report by Digital Currency Initiative & Center for Civic Media

Bookmarked Back to the Future: The Decentralized Web, A report by the Digital Currency Initiative and the Center for Civic Media (Digital Currency Initiative / MIT Media Lab)

The Web is a key space for civic debate and the current battleground for protecting freedom of expression. However, since its development, the Web has steadily evolved into an ecosystem of large, corporate-controlled mega-platforms which intermediate speech online. In many ways this has been a positive development; these platforms improved usability and enabled billions of people to publish and discover content without having to become experts on the Web’s intricate protocols. But in other ways this development is alarming. Just a few large platforms drive most traffic to online news sources in the U.S., and thus have enormous influence over what sources of information the public consumes on a daily basis. The existence of these consolidated points of control is troubling for many reasons. A small number of stakeholders end up having outsized influence over the content the public can create and consume. This leads to problems ranging from censorship at the behest of national governments to more subtle, perhaps even unintentional, bias in the curation of content users see based on opaque, unaudited curation algorithms. The platforms that host our networked public sphere and inform us about the world are unelected, unaccountable, and often impossible to audit or oversee. At the same time, there is growing excitement around the area of decentralized systems, which have grown in prominence over the past decade thanks to the popularity of the cryptocurrency Bitcoin. Bitcoin is a payment system that has no central points of control, and uses a novel peer-to-peer network protocol to agree on a distributed ledger of transactions, the blockchain. Bitcoin paints a picture of a world where untrusted networks of computers can coordinate to provide important infrastructure, like verifiable identity and distributed storage. Advocates of these decentralized systems propose related technology as the way forward to “re-decentralize” the Web, by shifting publishing and discovery out of the hands of a few corporations, and back into the hands of users. These types of code-based, structural interventions are appealing because in theory, they are less corruptible and resistant to corporate or political regulation. Surprisingly, low-level, decentralized systems don’t necessarily translate into decreased market consolidation around user-facing mega-platforms. In this report, we explore two important ways structurally decentralized systems could help address the risks of mega-platform consolidation: First, these systems can help users directly publish and discover content directly, without intermediaries, and thus without censorship. All of the systems we evaluate advertise censorship-resistance as a major benefit. Second, these systems could indirectly enable greater competition and user choice, by lowering the barrier to entry for new platforms. As it stands, it is difficult for users to switch between platforms (they must recreate all their data when moving to a new service) and most mega-platforms do not interoperate, so switching means leaving behind your social network. Some systems we evaluate directly address the issues of data portability and interoperability in an effort to support greater competition.

Download .pdf

h/t Ethan Zuckerman
Related to http://boffosocko.com/2017/08/19/mastodon-is-big-in-japan-the-reason-why-is-uncomfortable-by-ethan-zuckerman/

🔖 Elementary Algebraic Geometry by Klaus Hulek

Bookmarked Elementary Algebraic Geometry (Student Mathematical Library, Vol. 20) (American Mathematical Society)

This is a genuine introduction to algebraic geometry. The author makes no assumption that readers know more than can be expected of a good undergraduate. He introduces fundamental concepts in a way that enables students to move on to a more advanced book or course that relies more heavily on commutative algebra. The language is purposefully kept on an elementary level, avoiding sheaf theory and cohomology theory. The introduction of new algebraic concepts is always motivated by a discussion of the corresponding geometric ideas. The main point of the book is to illustrate the interplay between abstract theory and specific examples. The book contains numerous problems that illustrate the general theory. The text is suitable for advanced undergraduates and beginning graduate students. It contains sufficient material for a one-semester course. The reader should be familiar with the basic concepts of modern algebra. A course in one complex variable would be helpful, but is not necessary. It is also an excellent text for those working in neighboring fields (algebraic topology, algebra, Lie groups, etc.) who need to know the basics of algebraic geometry.

Dr. Miller emailed me yesterday to confirm that the textbook for his Fall UCLA Extension ‏course Introduction to Algebraic Geometry will be Elementary Algebraic Geometry by Klaus Hulek (AMS, 2003) ISBN: 0-8218-2952-1.

Sadly, I totally blew the prediction of which text he’d use. I was so far off that this book wasn’t even on my list to review! I must be slipping…

🔖 Universal Sign-In Button

Bookmarked Universal Sign-In Button by Malcolm Blaney (unicyclic.com)

The Universal Sign-In Button is a customisable bookmarklet that will auto-fill a sign-in form on the page you are currently visiting and submit it for you. It's a one-click way to tell the current page who you are.

This is simply awesome! I’m such a fan of bookmarklets I actually feel sad I hadn’t thought of doing this before. This simple Universal Sign-in Button tool now greatly reduces the amount of time it takes me to log into IndieWeb and other related sites that offer this functionality.

Signing into websites using my own domain name was an awesome concept, but this greatly speeds up the process and makes it an order of magnitude faster.

Thanks Malcolm!

🔖 Self-Organized Resonance during Search of a Diverse Chemical Space

Bookmarked Self-Organized Resonance during Search of a Diverse Chemical Space (Physical Review Letters)

ABSTRACT Recent studies of active matter have stimulated interest in the driven self-assembly of complex structures. Phenomenological modeling of particular examples has yielded insight, but general thermodynamic principles unifying the rich diversity of behaviors observed have been elusive. Here, we study the stochastic search of a toy chemical space by a collection of reacting Brownian particles subject to periodic forcing. We observe the emergence of an adaptive resonance in the system matched to the drive frequency, and show that the increased work absorption by these resonant structures is key to their stabilization. Our findings are consistent with a recently proposed thermodynamic mechanism for far-from-equilibrium self-organization.

Suggested by First Support for a Physics Theory of Life in Quanta Magazine.

🔖 Spontaneous fine-tuning to environment in many-species chemical reaction networks | PNAS

Bookmarked Spontaneous fine-tuning to environment in many-species chemical reaction networks (Proceedings of the National Academy of Sciences)

Significance A qualitatively more diverse range of possible behaviors emerge in many-particle systems once external drives are allowed to push the system far from equilibrium; nonetheless, general thermodynamic principles governing nonequilibrium pattern formation and self-assembly have remained elusive, despite intense interest from researchers across disciplines. Here, we use the example of a randomly wired driven chemical reaction network to identify a key thermodynamic feature of a complex, driven system that characterizes the “specialness” of its dynamical attractor behavior. We show that the network’s fixed points are biased toward the extremization of external forcing, causing them to become kinetically stabilized in rare corners of chemical space that are either atypically weakly or strongly coupled to external environmental drives. Abstract A chemical mixture that continually absorbs work from its environment may exhibit steady-state chemical concentrations that deviate from their equilibrium values. Such behavior is particularly interesting in a scenario where the environmental work sources are relatively difficult to access, so that only the proper orchestration of many distinct catalytic actors can power the dissipative flux required to maintain a stable, far-from-equilibrium steady state. In this article, we study the dynamics of an in silico chemical network with random connectivity in an environment that makes strong thermodynamic forcing available only to rare combinations of chemical concentrations. We find that the long-time dynamics of such systems are biased toward states that exhibit a fine-tuned extremization of environmental forcing.

Suggested by First Support for a Physics Theory of Life in Quanta Magazine.

Introduction to Algebraic Geometry | UCLA Extension in Fall 2017

Bookmarked MATH X 451.42 Introduction to Algebraic Geometry (UCLA Extension)

Algebraic geometry is the study, using algebraic tools, of geometric objects defined as the solution sets to systems of polynomial equations in several variables. This introductory course, the first in a two-quarter sequence, develops the basic theory of the subject, beginning with seminal theorems—the Hilbert Basis Theorem and Hilbert’s Nullstellensatz—that establish the dual relationship between so-called varieties—both affine and projective—and certain ideals of the polynomial ring in some number of variables. Topics covered in this first quarter include: algebraic sets, projective spaces, Zariski topology, coordinate rings, the Grassmannian, irreducibility and dimension, morphisms, sheaves, and prevarieties. The theoretical discussion will be supported by a large number of examples and exercises. The course should appeal to those with an interest in gaining a deeper understanding of the mathematical interplay among algebra, geometry, and topology. Prerequisites: Some exposure to advanced mathematical methods, particularly those pertaining to ring theory, fields extensions, and point-set topology.

Dr. Michael Miller has announced the topic for his Fall math class at UCLA Extension: Algebraic Geometry!!

Yes math fans, as previously hinted at in prior conversations, we’ll be taking a deep dive into the overlap of algebra and geometry. Be sure to line up expeditiously as registration for the class won’t happen until July 31, 2017.

While it’s not yet confirmed, some sources have indicated that this may be the first part of a two quarter sequence on the topic. As soon as we have more details, we’ll post them here first. As of this writing, there is no officially announced textbook for the course, but we’ve got some initial guesses and the best are as follows (roughly in decreasing order):

Ideals, Varieties, and Algorithms: An Introduction to Computational Algebraic Geometry and Commutative Algebra (Undergraduate Texts in Mathematics) 4th ed. by David A. Cox, John Little, and Donal O’Shea
Algebraic Geometry: An Introduction (Universitext) by Daniel Perrin
An Invitation to Algebraic Geometry (Universitext) by Karen E. Smith, Lauri Kahanpää, Pekka Kekäläinen, William Traves
Algebraic Geometry (Dover Books on Mathematics) by Solomon Lefschetz (Less likely based on level and age, but Dr. Miller does love inexpensive Dover editions)

For those who are new to Dr. Miller’s awesome lectures, I’ve written some hints and tips on what to expect.

Most of his classes range from about 20-30 people, many of them lifelong regulars. (Yes, there are dozens of people like me who will take almost everything he teaches–he’s that good. This class, my 22nd, will be the start of my second decade of math with him.)

🔖 Communication complexity of approximate Nash equilibria | arXiv

Bookmarked Communication complexity of approximate Nash equilibria (arXiv)

For a constant ϵ, we prove a poly(N) lower bound on the (randomized) communication complexity of ϵ-Nash equilibrium in two-player NxN games. For n-player binary-action games we prove an exp(n) lower bound for the (randomized) communication complexity of (ϵ,ϵ)-weak approximate Nash equilibrium, which is a profile of mixed actions such that at least (1−ϵ)-fraction of the players are ϵ-best replying.

Suggested by In Game Theory, No Clear Path to Equilibrium by Erica Klarreich (Quanta Magazine)