12295
Flowers for Julia | Fronkonstin
To color the points, I pick a random palette from the top list of COLOURLovers site using the colourlovers package. Since each flower involves a huge amount of calculations, I use Reduce to make this process efficiently. More examples:
fractals  visualization  color  details-of-note 
5 hours ago
Tanya Khovanova's Math Blog » Blog Archive » Another Cool Coin-Weighing Problem
My coauthor, Konstantin Knop, sent me a coin-weighing problem that is really good. Surprisingly, it is old: it first appeared in a Russian math journal, Kvant, in 1973.
mathematical-recreations  constraint-satisfaction  rather-interesting  nudge-targets  to-write-about  to-generalize 
5 hours ago
[1207.4497] Efficient Algorithms for Zeckendorf Arithmetic
We study the problem of addition and subtraction using the Zeckendorf representation of integers. We show that both operations can be performed in linear time; in fact they can be performed by combinational logic networks with linear size and logarithmic depth. The implications of these results for multiplication, division and square-root extraction are also discussed.
arithmetic  representation  rather-interesting  mathematical-recreations  nudge-targets  consider:rediscovery 
yesterday
3 tools from sociocracy to use right away (plus magic phrases!)
Of course I myself am ego-driven and I have a ton of good ideas! But I also know that it only takes one person in the circle engaging in cross-talk and the good effects of rounds are lost. What do I do with all my brilliant ideas? I write them on a piece of paper. When it is my turn, I will often look at my piece of paper and realize that, after a few minutes of listening to others, about 90% of my ideas have either been named or, on second thought, they don’t seem all that great or urgent anymore. Humbled, I am often grateful for having been forced to weed through what I say. And when people pass on their turn saying “All I wanted to say has been said” I feel the urge to get up and hug them in gratitude for not putting the group through endless repetitions. Which also answers the last reservation I hear very often: aren’t rounds lenghty? Maybe. But both inconsiderate decisions, repetitive statements and emotional “clean-up” after disregard of team members takes a lot of time too. Your choice!
social-dynamics  social-norms  collaboration  organizational-behavior  teams  rather-interesting  to-write-about 
3 days ago
[PDF] The Spread of Improvement: Why Innovation Accelerated in Britain 1547-1851
In the three centuries after the reign of Henry VIII, the British Isles emerged from civil wars, invasion threats, and religious strife to become the world's technological leader. Why did innovation accelerate? I studied the people responsible, the innovators themselves, using a sample of 1,452 people in Britain who innovated between 1547 and 1851.

The paper charts the emergence and spread of an improving mentality, tracing its transmission from person to person and across the country. The mentality was not a technique, skill, or special understanding, but a frame of mind: innovators saw room for improvement where others saw none. The mentality could be received by anyone, and it could be applied to any field – anything, after all, could be better.

But what led to innovation’s acceleration was not just that the mentality spread: over the course of the eighteenth century innovators became increasingly committed to spreading the mentality further – they became innovation’s evangelists. By creating new institutions and adopting social norms conducive to openness and active sharing, innovators ensured the continued dissemination of innovation, giving rise to modern economic growth in Britain and abroad.
epidemiology-of-ideas  symmathesy  rather-interesting  topical  history-of-ideas  collaboration  the-mangle-in-practice  sociotechnical-us 
3 days ago
[1810.07074] Why We Do Not Evolve Software? Analysis of Evolutionary Algorithms
In this paper, we review the state-of-the-art results in evolutionary computation and observe that we do not evolve non trivial software from scratch and with no human intervention. A number of possible explanations are considered, but we conclude that computational complexity of the problem prevents it from being solved as currently attempted. A detailed analysis of necessary and available computational resources is provided to support our findings.
via:lspector  yeah-no  nimby  system-of-professions  mistaking-the-publications-for-the-work  academic-culture 
3 days ago
Automating String Processing in Spreadsheets using Input-Output Examples - Microsoft Research
We describe the design of a string programming/expression language that supports restricted forms of regular expressions, conditionals and loops. The language is expressive enough to represent a wide variety of string manipulation tasks that end-users struggle with. We describe an algorithm based on several novel concepts for synthesizing a desired program in this language from input-output examples. The synthesis algorithm is very efficient taking fraction of a second for various benchmark examples. The synthesis algorithm is interactive and has several desirable features: it can rank multiple solutions and has fast convergence, it can detect noise in the user input, and it supports an active interaction model wherein the user is prompted to provide outputs on inputs that may have multiple computational interpretations.

The algorithm has been implemented as an interactive add-in for Microsoft Excel spreadsheet system. The prototype tool has met the golden test – it has synthesized part of itself, and has been used to solve problems beyond authors’ imagination.
learning-from-data  microsoft  software-synthesis  rather-interesting  pattern-discovery  to-write-about 
3 days ago
[PDF] MEXICA: a computer model of a cognitive account of creative writing.
MEXICA is a computer model that produces frameworks for short stories based on the engagement-reflection cognitive account of writing. During engagement MEXICA generates material guided by content and rhetorical constraints, avoiding the use of explicit goals or story- structure information. During reflection the system breaks impasses, evaluates the novelty and interestingness of the story in progress and verifies that coherence requirements are satisfied. In this way, MEXICA complements and extends those models of computerised story-telling based on traditional problem-solving techniques where explicit goals drive the generation of stories. This paper describes the engagement-reflection account of writing, the general characteristics of MEXICA and reports an evaluation of the program
generative-models  cognition  simulation  looking-to-see  cultural-engineering  rather-interesting  representation  to-write-about 
7 days ago
Domain hacks with unusual Unicode characters – Terence Eden's Blog
Unicode contains a range of symbols which don't get much use. For example, there are separate symbols for TradeMark - ™, Service Mark - ℠, and Prescriptions - ℞.
Nestling among the "Letterlike Symbols" are two curious entries. Both of these are single characters:
Telephone symbol - ℡
Numero Sign - №
What's interesting is both .tel and .no are Top-Level-Domains (TLD) on the Domain Name System (DNS).
typography  domains  DNS  rather-odd 
7 days ago
[1705.07386] DeepMasterPrints: Generating MasterPrints for Dictionary Attacks via Latent Variable Evolution
Recent research has demonstrated the vulnerability of fingerprint recognition systems to dictionary attacks based on MasterPrints. MasterPrints are real or synthetic fingerprints that can fortuitously match with a large number of fingerprints thereby undermining the security afforded by fingerprint systems. Previous work by Roy et al. generated synthetic MasterPrints at the feature-level. In this work we generate complete image-level MasterPrints known as DeepMasterPrints, whose attack accuracy is found to be much superior than that of previous methods. The proposed method, referred to as Latent Variable Evolution, is based on training a Generative Adversarial Network on a set of real fingerprint images. Stochastic search in the form of the Covariance Matrix Adaptation Evolution Strategy is then used to search for latent input variables to the generator network that can maximize the number of impostor matches as assessed by a fingerprint recognizer. Experiments convey the efficacy of the proposed method in generating DeepMasterPrints. The underlying method is likely to have broad applications in fingerprint security as well as fingerprint synthesis.
evolutionary-algorithms  neural-networks  generative-models  rather-interesting  biometrics  whoopsie-daisy  also:duh 
7 days ago
Pseudoarchaeology and the Racism Behind Ancient Aliens
If we look to von Däniken’s work, there can be little doubt that his racial beliefs influenced his extraterrestrial theories. After a short stint in jail for fraud and either writing or appropriating the material for a number of other books that developed his ancient astronauts theory, von Däniken published Signs of the Gods? in 1979. It is here that many of his racial views are most boldly stated. British archaeology officer Keith Fitzpatrick-Matthews points out on his Bad Archaeology blog just a few of the many racist questions and statements posed by the author: “Was the black race a failure and did the extraterrestrials change the genetic code by gene surgery and then programme a white or a yellow race?” He also printed beliefs about the innate talents of certain races: “Nearly all negroes are musical; they have rhythm in their blood.” Von Däniken also consistently uses the term “negroid race” in comparison with “Caucasians.”
racism  psychoceramics  imperialism  archaeology  have-read  spacemen-and-cavemen 
7 days ago
Quinn Slobodian – Globalists — Crooked Timber
Slobodian thinks that this is mistaken. In his account, markets have not become disembedded from national societies and states so much as they have become re-embedded in international institutions. Neo-liberalism as manifested in the thought of Hayek and his European followers is the political project of looking to recreate state structures outside the grasp of democratic and non-democratic states. Far from thinking that markets are natural, neo-liberals accept that they are “products of the political construction of institutions to encase them.” (p.7) Instead of a double movement, we have a ‘double world’ of imperium, political rule exercised through nation states, and dominium, the world of economics and business, and a deliberate political effort to insulate the latter inside its own steel-hard casing against the depredations of the former. Neo-liberals then, look to an `interdependent’ world and a single global economy as a realm that should be held inviolate from national states, and the demands their people put upon them. This, as they came to realize over time, requires them to build their own quasi-constitutional structures at the international level, in order to fend off the persistent efforts of national states to shape and control competitive forces and economic flows that are better left alone.

Under this account, the most crucial dynamics of neo-liberalism did not involve the glamorous public clash of ideas between intellectuals. Instead, they were duller, more relentless and in the end, more effective – the persistent efforts of neo-liberals to argue through new kinds of international institution and to push back against organized efforts to make global markets more accountable to national authorities. Mont Pelerin was important – but so too were the International Chamber of Commerce and a multitude of boring seeming meetings and negotiations.
neoliberalism  books  political-economy  define-your-terms  to-read  if-I-have-the-guts  fascism 
9 days ago
Making Sense of Bivector Addition, viXra.org e-Print archive, viXra:1807.0234
As a demonstration of the coherence of Geometric Algebra's (GA's) geometric and algebraic concepts of bivectors, we add three geometric bivectors according to the procedure described by Hestenes and Macdonald, then use bivector identities to determine, from the result, two bivectors whose outer product is equal to the initial sum. In this way, we show that the procedure that GA's inventors dened for adding geometric bivectors is precisely that which is needed to give results that coincide with those obtained by calculating outer products of vectors that are expressed in terms of a 3D basis. We explain that that accomplishment is no coincidence: it is a consequence of the attributes that GA's designers assigned (or didn't) to bivectors.
linear-algebra  algebra  define-your-terms  rather-interesting  to-write-about  nudge-targets  consider:representation  Grassmannian  wedge-product 
9 days ago
The Arbelos in Wasan Geometry, Problems of Izumiya and Nait=o, viXra.org e-Print archive, viXra:1811.0132
We generalize two sangaku problems involving an arbelos proposed by Izumiya and Nait\=o, and show the existence of six non-Archimedean congruent circles.
plane-geometry  nanohistory  to-write-about  nudge-targets  consider:rediscovery 
9 days ago
Robinson Tiles - Futility Closet
Berkeley mathematician Raphael Robinson discovered this remarkable set of aperiodic tiles in 1978. The six shapes will neatly tile a plane, as shown below, and though the pattern cannot be regular, it reliably produces a hierarchical design: Each small orange square sits at the corner of a larger orange square, which sits at the corner of a still larger one, and so on ad infinitum. This is because subgroups of tiles form “supertiles” with similar properties — see here.
tiling  mathematical-recreations  aperiodic-patterns  constraint-satisfaction 
9 days ago
Problem Solving with Trig | Continuous Everywhere but Differentiable Nowhere
I’m going to try to outline the messiness that was my thought process in this triangle problem, to show/archive the messiness that is problem solving.

...

The point of this post isn’t to teach someone the solution to the problem. I could have written something much easier. (See we can draw this auxiliary line to create similar triangles. We use proportions since we have similar triangles. Then exploit the new isosceles triangle by setting the leg lengths equal to each other.) But that’s whitewashing all that went into the problem. It’s like a math paper or a science paper. It is a distillation of so freaking much. It was to capture what it’s like to not know something, and how my brain worked in trying to get to figure something out. To show what’s behind a solution.
problem-solving  plane-geometry  learning-in-public  pedagogy  to-write-about 
9 days ago
NeuralFunk - Combining Deep Learning with Sound Design
NeuralFunk - Combining Deep Learning with Sound Design
Making a Track Entirely out of Samples Generated by Neural Networks
rather-interesting  neural-networks  generative-art  learning-in-public  the-mangle-in-practice  to-write-about  performance-measure 
9 days ago
PsyArXiv Preprints | The rich are different: Unraveling the perceived and self-reported personality profiles of high net-worth individuals
Beyond money and possessions, how are the rich different from the general population? Drawing on a unique sample of high net-worth individuals from Germany (≥1 million Euro in financial assets; N = 130), nationally representative data (N = 22,981), and an additional online panel (N = 690), we provide the first direct investigation of the stereotypically-perceived and self-reported personality profiles of high net-worth individuals. Investigating the broad personality traits of the Big Five and the more specific traits of narcissism and locus of control, we find that stereotypes about wealthy people’s personality are accurate albeit somewhat exaggerated and that wealthy people can be characterized as stable, flexible, and agentic individuals who are focused more on themselves than on others.
psychology  wealth  capitalism  social-norms  cultural-norms  social-psychology  stereotypes  yup 
9 days ago
Shtetl-Optimized » Blog Archive » Lecture notes! Intro to Quantum Information Science
In Spring 2017, I taught a new undergraduate course at UT Austin, entitled Introduction to Quantum Information Science.  There were about 60 students, mostly CS but also with strong representation from physics, math, and electrical engineering.  One student, Ewin Tang, made a previous appearance on this blog.  But today belongs to another student, Paulo Alves, who took it upon himself to make detailed notes of all of my lectures.  Using Paulo’s notes as a starting point, and after a full year of procrastination and delays, I’m now happy to release the full lecture notes for the course.  Among other things, I’ll be using these notes when I teach the course a second time, starting … holy smokes … this Wednesday.
syllabus  quantum-computing  computer-science  class  to-read 
16 days ago
Ecological theory provides insights about evolutionary computation [PeerJ Preprints]
Evolutionary algorithms often incorporate ecological concepts to help maintain diverse populations and drive continued innovation. However, while there is strong evidence for the value of ecological dynamics, a lack of overarching theoretical framework renders the precise mechanisms behind these results unclear. These gaps in our understanding make it challenging to predict which approaches will be most appropriate for a given problem. Biologists have been developing ecological theory for decades, but the resulting body of work has yet to be translated into an evolutionary computation context. This paper lays the groundwork for such a translation by applying ecological theory to three different selection mechanisms in evolutionary computation: fitness sharing, lexicase selection, and Eco-EA. First, we use ecological ideas to establish a framework that clarifies how these selection schemes are alike and how they differ. We then build upon this framework by using metrics from ecology to gather empirical data about the underlying differences in the population dynamics that these approaches produce. Specifically, we measure interaction networks and phylogenetic diversity within the population to explore long-term stable coexistence. Notably, we find that selection methods affect phylogenetic diversity differently than phenotypic diversity. These results can inform parameter selection, choice of selection scheme, and the development of new selection schemes.
evolutionary-algorithms  selection  looking-to-see  rather-interesting  hey-I-know-these-folks  artificial-life  feature-construction  community-formation 
17 days ago
On exploring how to be online in radical ways
Web developer Tara Vancil discusses the peer-to-peer web, the current state of self-publishing, and the future of the internet.
peer-production  p2p  web  social-networks  social-affordances  to-write-about  to-understand 
17 days ago
[1805.03374] A Proposal for Loop-Transformation Pragmas
Pragmas for loop transformations, such as unrolling, are implemented in most mainstream compilers. They are used by application programmers because of their ease of use compared to directly modifying the source code of the relevant loops. We propose additional pragmas for common loop transformations that go far beyond the transformations today's compilers provide and should make most source rewriting for the sake of loop optimization unnecessary. To encourage compilers to implement these pragmas, and to avoid a diversity of incompatible syntaxes, we would like to spark a discussion about an inclusion to the OpenMP standard.
computer-science  compilers  rewriting-systems  refactoring  rather-interesting  to-understand  computational-complexity  optimization 
17 days ago
[1501.03043] Functionals and hardware
Functionals are an important research subject in Mathematics and Computer Science as well as a challenge in Information Technologies where the current programming paradigm states that only symbolic computations are possible on higher order objects, i.e. functionals are terms, and computation is term rewriting. The idea explored in the paper is that functionals correspond to generic mechanisms for management of connections in arrays consisting of first order functional units. Functionals are higher order abstractions that are useful for the management of such large arrays. Computations on higher order objects comprise dynamic configuration of connections between first order elementary functions in the arrays. Once the functionals are considered as the generic mechanisms, they have a grounding in hardware. A conceptual framework for constructing such mechanisms is presented, and their hardware realization is discussed.
representation  type-theory  define-your-terms  analogy  philosophy-of-engineering  mathematical-programming  to-write-about  to-understand  category-theory 
17 days ago
Quantum Epistemology for Business - Scientific American Blog Network
We are laboring under the illusion of “classical information” and “classical measurement” when we deal with human and organizational phenomena. Insights from quantum epistemology raise indelible doubts about the given-ness of data. But businesspeople need more than reasonable doubt: they need insights and action prompts. How can we leverage “quantum effects” in human organizations? The “quantum epistemology of social phenomena” is in its infancy, but already can provide a battery of new questions for those who want to understand and shape the process of measurement.
planning  define-your-terms  rather-interesting  models-and-modes  to-write-about  management 
17 days ago
[1807.10489] Randomized residual-based error estimators for parametrized equations
We propose a randomized a posteriori error estimator for reduced order approximations of parametrized (partial) differential equations. The error estimator has several important properties: the effectivity is close to unity with prescribed lower and upper bounds at specified high probability; the estimator does not require the calculation of stability (coercivity, or inf-sup) constants; the online cost to evaluate the a posteriori error estimator is commensurate with the cost to find the reduced order approximation; the probabilistic bounds extend to many queries with only modest increase in cost. To build this estimator, we first estimate the norm of the error with a Monte-Carlo estimator using Gaussian random vectors whose covariance is chosen according to the desired error measure, e.g. user-defined norms or quantity of interest. Then, we introduce a dual problem with random right-hand side the solution of which allows us to rewrite the error estimator in terms of the residual of the original equation. In order to have a fast-to-evaluate estimator, model order reduction methods can be used to approximate the random dual solutions. Here, we propose a greedy algorithm that is guided by a scalar quantity of interest depending on the error estimator. Numerical experiments on a multi-parametric Helmholtz problem demonstrate that this strategy yields rather low-dimensional reduced dual spaces.
numerical-methods  approximation  rather-interesting  to-understand  modeling  algorithms  to-write-about 
17 days ago
Quickly recognizing primes less than 1000: divisibility tests | The Math Less Traveled
In any case, today I want to return to the problem of quickly recognizing small primes. In my previous post we considered “small” to mean “less than 100”. Today we’ll kick it up a notch and consider recognizing primes less than 1000. I want to start by considering some simple approaches and see how far we can push them. In future posts we’ll consider some fancier things.
number-theory  heuristics  rather-interesting  algorithms  nudge-targets  consider:rediscovery 
17 days ago
[1810.10577] Cops and Robbers on Toroidal Chess Graphs
We investigate multiple variants of the game Cops and Robbers. Playing it on an n×n toroidal chess graph, the game is varied by defining moves for cops and robbers differently, always mimicking moves of certain chess pieces. In these cases, the cop number is completely determined.
graph-theory  games  rather-interesting  mathematical-recreations  feature-construction  to-write-about  to-simulate  nudge-targets  consider:classification 
18 days ago
[1302.1883] Mesh patterns with superfluous mesh
Mesh patterns are a generalization of classical permutation patterns that encompass classical, bivincular, Bruhat-restricted patterns, and some barred patterns. In this paper, we describe all mesh patterns whose avoidance is coincident with classical avoidance, in a sense declaring that the additional data of a mesh was unnecessary for these patterns. We also describe the permutations having the fewest superfluous meshes, and the permutations having the most, enumerating the superfluous meshes in each case.
permutations  combinatorics  representation  to-write-about  mathematical-recreations  pattern-discovery  feature-construction 
19 days ago
[1410.2353] Sorting Permutations: Games, Genomes, and Cycles
Permutation sorting, one of the fundamental steps in pre-processing data for the efficient application of other algorithms, has a long history in mathematical research literature and has numerous applications. Two special-purpose sorting operations are considered in this paper: context directed swap, abbreviated cds, and context directed reversal, abbreviated cdr. These are special cases of sorting operations that were studied in prior work on permutation sorting. Moreover, cds and cdr have been postulated to model molecular sorting events that occur in the genome maintenance program of certain species of single-celled organisms called ciliates.
This paper investigates mathematical aspects of these two sorting operations. The main result of this paper is a generalization of previously discovered characterizations of cds-sortability of a permutation. The combinatorial structure underlying this generalization suggests natural combinatorial two-player games. These games are the main mathematical innovation of this paper.
combinatorics  permutations  algorithms  game-theory  mathematical-recreations  to-write-about  consider:simulation  nudge-targets 
19 days ago
[1608.06931] Prolific permutations and permuted packings: downsets containing many large patterns
A permutation of n letters is k-prolific if each (n-k)-subset of the letters in its one-line notation forms a unique pattern. We present a complete characterization of k-prolific permutations for each k, proving that k-prolific permutations of m letters exist for every m \ge k^2/2+2k+1, and that none exist of smaller size. Key to these results is a natural bijection between k-prolific permutations and certain "permuted" packings of diamonds.
combinatorics  permutations  representation  tiling  to-understand  enumeration  optimization  packing  feature-construction 
19 days ago
[1704.05494] The pinnacle set of a permutation
Peak sets of a permutation record the indices of its peaks. These sets have been studied in a variety of contexts, including recent work by Billey, Burdzy, and Sagan, which enumerated permutations with prescribed peak sets. In this article, we look at a natural analogue of the peak set of a permutation, instead recording the values of the peaks. We define the "pinnacle set" of a permutation w to be the set {w(i) : i is a peak of w}. Although peak sets and pinnacle sets mark the same phenomenon, these objects differ in notable ways. In the work below, we characterize admissible pinnacle sets and study various enumerative questions related to these objects.
combinatorics  permutations  representation  to-understand  feature-construction  to-write-about 
19 days ago
[1811.00082] Tiling-based models of perimeter and area
We consider polygonal tilings of certain regions and use these to give intuitive definitions of tiling-based perimeter and area. We apply these definitions to rhombic tilings of Elnitsky polygons, computing sharp bounds and average values for perimeter tiles in convex centrally symmetric 2n-gons. These bounds and values have Coxeter-theoretic implications for the commutation classes of the longest element in the symmetric group. We also classify the permutations whose polygons have minimal perimeter, defined in two different ways, and we conclude by looking at some of these questions in the context of domino tilings of rectangles, giving a recursive formula and generating function for one family. Throughout the work, we contrast the tiling-based results that we obtain with classical contour-based isoperimetric results.
combinatorics  permutations  rather-interesting  tiling  to-understand  representation 
19 days ago
[1802.06668] Sequentializing cellular automata
We study the problem of sequentializing a cellular automaton without introducing any intermediate states, and only performing reversible permutations on the tape. We give a decidable characterization of cellular automata which can be written as a single left-to-right sweep of a bijective rule from left to right over an infinite tape.
cellular-automata  representation  rather-interesting  a-bit-backwards-though  complexology  computational-complexity  to-write-about  consider:looking-to-see 
20 days ago
PsyArXiv Preprints | Cognitive attraction and online misinformation
The spread of online misinformation has gained mainstream attention in recent years. Here I approach this phenomenon from a cultural evolution and cognitive anthropology perspective, focusing on the idea that some cultural traits can be successful because their content taps into general cognitive preferences. I analyse 260 articles from media outlets included in two authoritative lists of websites known for publishing hoaxes and ‘fake news’, tracking the presence of negative content, threat-related information, presence of sexually related material, elements associated to disgust, minimally counterintuitive elements (and a particular category of them, i.e. violations of essentialist beliefs), and social information, intended as presence of salient social interactions (e.g. gossip, cheating, formation of alliances), and as news about celebrities. The analysis shows that these features are, to a different degree, present in most texts, and thus that general cognitive inclinations may contribute to explain the success of online misinformation. I conclude discussing how this account can elucidate questions such as whether and why misinformation online is thriving more than accurate information, or the role of ‘fake news’ as a weapon of political propaganda. Online misinformation, while being an umbrella term covering many different phenomena, can be characterised, in this perspective, not as low-quality information that spread because of the inefficiency of online communication, but as high-quality information that spread because of its efficiency. The difference is that ‘quality’ is not equated to truthfulness but to psychological appeal.
social-dynamics  critical-thinking  rather-interesting  anthropology  to-read  cultural-dynamics 
20 days ago
Semantic information, agency, & physics | Interface Focus
Shannon information theory provides various measures of so-called syntactic information, which reflect the amount of statistical correlation between systems. By contrast, the concept of ‘semantic information’ refers to those correlations which carry significance or ‘meaning’ for a given system. Semantic information plays an important role in many fields, including biology, cognitive science and philosophy, and there has been a long-standing interest in formulating a broadly applicable and formal theory of semantic information. In this paper, we introduce such a theory. We define semantic information as the syntactic information that a physical system has about its environment which is causally necessary for the system to maintain its own existence. ‘Causal necessity’ is defined in terms of counter-factual interventions which scramble correlations between the system and its environment, while ‘maintaining existence’ is defined in terms of the system's ability to keep itself in a low entropy state. We also use recent results in non-equilibrium statistical physics to analyse semantic information from a thermodynamic point of view. Our framework is grounded in the intrinsic dynamics of a system coupled to an environment, and is applicable to any physical system, living or otherwise. It leads to formal definitions of several concepts that have been intuitively understood to be related to semantic information, including ‘value of information’, ‘semantic content’ and ‘agency’.
complexity  philosophy-of-science  information-theory  define-your-terms  hey-I-know-this-guy  semantics  to-understand  cannot-read 
20 days ago
Welcome to Feiba Peveli – Aaron A. Reed – Medium
The algorithm can also be scaled up or down to talk about smaller or larger areas. At 40 degrees N or S, each minute of latitude is about a mile apart; we could talk about going over to Imree Vadeto (the west side of Santa Cruz), the Imie Vadet urban area or Im Vade county; or you could go over to a particular person’s house, Imreela Vadetido (and I hope they’ve inscribed that on the gate). It would be kind of cool to just write Imreela Vadetido on a postcard and have it get delivered to the right place. (OK, nine-digit zip codes basically do that already, but feel significantly less like casting a spell.) Heck, imagine a world where people’s proper names worked this way, so your name encoded the exact location of your birth!
nanohistory  schemes  utopianism  rather-interesting  to-write-about  representation 
20 days ago
Jupyter, Mathematica, and the Future of the Research Paper – Paul Romer
Jupyter rewards transparency; Mathematica rationalizes secrecy. Jupyter encourages individual integrity; Mathematica lets individuals hide behind corporate evasion. Jupyter exemplifies the social systems that emerged from the Scientific Revolution and the Enlightenment, systems that make it possible for people to cooperate by committing to objective truth; Mathematica exemplifies the horde of new Vandals whose pursuit of private gain threatens a far greater pubic loss–the collapse of social systems that took centuries to build.
data-analysis  user-experience  open-source  academic-culture  startup-culture-must-die  literate-programming  open-access  literary-criticism 
20 days ago
Image Composite Editor - Microsoft Research
Image Composite Editor (ICE) is an advanced panoramic image stitcher created by the Microsoft Research Computational Photography Group. Given a set of overlapping photographs of a scene shot from a single camera location, the app creates high-resolution panoramas that seamlessly combine original images. ICE can also create panoramas from a panning video, including stop-motion action overlaid on the background. Finished panoramas can be saved in a wide variety of image formats, including JPEG, TIFF, and Photoshop’s PSD/PSB format, as well as the multiresolution tiled format used by HD View and Deep Zoom.
photography  software  algorithms  to-do 
20 days ago
ChrisKnott/Algojammer: An experimental code editor for writing algorithms
Algojammer is an experimental, proof-of-concept code editor for writing algorithms in Python. It was mainly written to assist with solving the kind of algorithm problems that feature in competitions like Google Code Jam, Topcoder and HackerRank.
algorithms  python  visualization  rather-interesting  text-editor  simulation  to-write-about 
20 days ago
ChipChip: A new sort of sorting |
A uniquely French way to express contempt for someone is to call them an “espèce d’espèce” (see Endnote #1); literally, “a sort of a sort”.  This month I’m going to tell you about a sort of a sort (or rather, a sort of sorting) that, from a practical standpoint, merits this degree of contempt: the procedure is ambiguous, is annoyingly slow, and doesn’t always sort things correctly. Yet there’s an unresolved mathematical mystery arising from the way that the procedure works better than it has any right to.
algorithms  sorting  rather-interesting  to-write-about  exploding-dots  to-simulate  nudgelike 
20 days ago
[1810.04756] Stochastic Synthesis for Stochastic Computing
Stochastic computing (SC) is an emerging computing technique which offers higher computational density, and lower power over binary-encoded (BE) computation. Unlike BE computation, SC encodes values as probabilistic bitstreams which makes designing new circuits unintuitive. Existing techniques for synthesizing SC circuits are limited to specific classes of functions such as polynomial evaluation or constant scaling. In this paper, we propose using stochastic synthesis, which is originally a program synthesis technique, to automate the task of synthesizing new SC circuits. Our results show stochastic synthesis is more general than past techniques and can synthesize manually designed SC circuits as well as new ones such as an approximate square root unit.
via:jhmoore  representation  genetic-programming  circuits  rather-interesting  computational-methods  to-write-about  to-simulate 
24 days ago
Thinking Toys – Gary Basin's words
My mind seems to mostly act as an emotional problem-solving machine. It’s trying to find paths to get to pleasure and avoid pain. Of course, this often requires solving abstract problems, as well. Watching myself, and others, identify and solve problems suggests the existence of underlying patterns. There seem to be recurring strategies. Some simple and some compound. Some that an individual may use almost every time and others that rarely come up. There are strategies that seem obvious to one person and remain unheard of to others. Sometimes we deploy these strategies consciously but often they seem to run unconsciously.

I call these strategies Thinking Toys. Little tricks we can pick up, play with for a moment, and then throw aside as we move on. Using a toy more often seems to make it more accessible. We also learn more of its nuances — we improve at using it. I’m trying to explicate as many of these as I can. Eventually, I want to categorize them and try to understand how they relate to each other.

See if any of these are interesting to you. Some will be familiar and obvious, whereas others may feel strange and alien.
introspection  mental-health  exercises  kata  rather-interesting 
25 days ago
Object-oriented Computation of Sandwich Estimators | Zeileis | Journal of Statistical Software
Sandwich covariance matrix estimators are a popular tool in applied regression modeling for performing inference that is robust to certain types of model misspecification. Suitable implementations are available in the R system for statistical computing for certain model fitting functions only (in particular lm()), but not for other standard regression functions, such as glm(), nls(), or survreg(). Therefore, conceptual tools and their translation to computational tools in the package sandwich are discussed, enabling the computation of sandwich estimators in general parametric models. Object orientation can be achieved by providing a few extractor functions' most importantly for the empirical estimating functions' from which various types of sandwich estimators can be computed.
via:cshalizi  to-understand  statistics  estimation  algorithms  programming  regression  error-measures  modeling 
25 days ago
God Help Us, Let’s Try To Understand Friston On Free Energy | Slate Star Codex
Normally this is the point at which I say “screw it” and give up. But almost all the most interesting neuroscience of the past decade involves this guy in one way or another. He’s the most-cited living neuroscientist, invented large parts of modern brain imaging, and received the prestigious Golden Brain Award (which is somehow a real thing). His Am I Autistic – An Intellectual Autobiography short essay, written in a weirdly lucid style and describing hijinks like deriving the Schrodinger equation for fun in school, is as consistent with genius as anything I’ve ever read.
define-your-terms  understanding-oversmart-people  cognition  simple-models-of-simple-models  Bayesian-all-the-things  to-watch  academic-culture  oh-look-Schmidhuber-too 
25 days ago
Privacy, Security, & Ethics – Computer Science’s “Jüdische Physik” – Terence Eden's Blog
I'm going to tell you an anecdote which is a gross oversimplification, and is an unfair comparison.
In the early part of the twenty-first century, many people working in the fledgeling Internet industry started making noise about privacy, security, and ethics. The mainstream technologists called them fearmongers, idealists, and anti-business. Their ideas were unwelcome and they were thrown out of both the cathedral and the bazaar.
Many retreated to academia, some stayed and tried to cultivate a sense of responsibility in the industry, a few started lobbying governments around the world. By the time trust in the existing structures had begun to collapse, there were too few privacy-focused employees left to reverse the damage.
By expelling the boring and pessimistic doomsayers, the Internet behemoths had sowed the seeds of their own destruction.
security  professionalism  online-culture  privacy  startup-culture-must-die  cultural-assumptions 
26 days ago
The nxnxn Dots Problem Optimal Solution, viXra.org e-Print archive, viXra:1707.0298
We provide an optimal strategy to solve the n X n X n points problem inside the box, considering only 90° turns, and at the same time a pattern able to drastically lower down the known upper bound. We use a very simple spiral frame, especially if compared to the previous plane by plane approach, that significantly reduces the number of straight lines connected at their end-points necessary to join all the n^3 dots. In the end, we combine the square spiral frame with the rectangular spiral pattern in the most profitable way, in order to minimize the difference between the upper and the lower bound, proving that it is ≤ 0.5 ∙ n ∙ (n + 3), for any n > 1.
mathematical-recreations  problem-solving  optimization  nudge-targets  consider:looking-to-see  to-write-about 
28 days ago
The n X n X n Dots Problem: An Improved “Outside the Box” Upper Bound, viXra.org e-Print archive, viXra:1807.0384
In this paper we describe two new patterns, in order to improve the upper bound for the Ripà’s n X n X n points problem, saving a few lines for many values of n. The new upper bound, for any n≥6, becomes h_u(n)=int((3/2*n^2)+int(n/4)-int((n-1)/4)+int((n+1)/4)-int((n+2)/4)+n-2, where int(x)≔floor(x).
mathematical-recreations  cannot-read  to-translate  out-of-the-box  to-write-about 
28 days ago
Meet the Endoterrestrials - The Atlantic
Even as Onstott awaits those results, he is starting to consider an even more radical possibility: that deep-dwelling microbes don’t just feed off of earthquakes, but might also trigger them. He believes that as microbes attack the iron, manganese, and other elements in the minerals that line the fault, they could weaken the rock—and prime the fault for its next big slip. Exploring that possibility would mean doing laboratory experiments to find out whether microbes in a fault can actually break down minerals quickly enough to affect seismic activity. With a scientist’s characteristic understatement, he contemplates the work ahead: “It’s a reasonable hypothesis to test.”
astrobiology  microbiology  told-em-so  it's-a-microbial-world 
28 days ago
the perpetual beta coffee club
This year I started the coffee club as a way to focus on people who were willing to take a very small leap across the financial chasm. Since January I have offered a private community space to anyone willing to pay $5 per month. Of the tens of thousands of people who read my work, I now have about 30 40 paid members of the Perpetual Beta Coffee Club (trademark nonexistent). As it grows — which is my hope — I will focus more of my energy there. So far we have a discussion forum and I host live web video chats monthly. These are recorded and available for 30 days. We try to ensure that what is discussed inside the coffee club stays there. I want to keep it as a trusted space. If the club grows, I intend to grow the services and offer a more robust community technology platform.

We are now six months in and there are people from Australia, Brazil, Canada, Denmark, Finland, France, Germany, New Zealand, Norway, South Africa, Spain, Sweden, UK, & USA. It’s a pretty eclectic group and while the main focus is workplace learning, we talk about whatever interests our members. The surveillance economy, and how to deal with it, was a recent topic.

I will keep on supporting our club and may some day turn it into my main professional focus. It’s much more fun to work with people who appreciate what you do and are willing to show it, not just use your work.
conversation  play-your-ukulele  revenue  to-emulate 
28 days ago
Laudator Temporis Acti: Invisibility
All people who work with their hands are partly invisible, and the more important the work they do, the less visible they are.
bullshit-jobs  worklife  public-policy  cultural-norms  quotes 
29 days ago
The Primordial Gound – The Public Domain Review
The piece that follows displays a number of the signature characteristics of the classic nineteenth-century genre known as mystification. We have an author who takes us winningly into his confidence as he discusses an intricate tale of old texts lost and recovered, all the while tipping his hand concerning the ambiguous status of the source material at issue. Kant in Sumatra? The Third Critique and the cosmologies of Melanesia? What is going on? Read on, and make of all of this what you will (or can!). But a quick thought: much philosophy (Justin E. H. Smith’s stock-in-trade), like most argumentative writing in history and every other branch of learned endeavor, seeks to compel assent — to leave the reader as little room as possible for thought-escape. To think well in such a textual ecology demands the cultivation of a capacity to find what we might think of as “worm holes” in the world of learned scholarship: loci that drop open into the infinite space of other possibilities. Sometimes such trapdoors can be opened in a footnote or paratext, or, as here, in a tiny textual emendation, through which we are encouraged to glimpse a thoroughly different fundamental ground for all experience. I am not a Geisterseher, Professor Skrastiņš assures Professor Smith — not a ghost-seer. But is that what we need to be if we are to see clearly through the heavy curtains of erudition?
history  explorations  amusing  to-do  to-write-about  to-follow  paratext 
4 weeks ago
viXra.org open e-Print archive
An alternative archive of 26146 e-prints in Science and Mathematics serving the whole scientific community
preprints  archive  discovered-in-passing 
4 weeks ago
An Upper Bound for Lebesgue’s Universal Covering Problem, viXra.org e-Print archive, viXra:1801.0292
The universal covering problem as posed by Henri Lebesgue in 1914 seeks to find the convex planar shape of smallest area that contains a subset congruent to any point set of unit diameter in the Euclidean plane. Methods used previously to construct such a cover can be refined and extended to provide an improved upper bound for the optimal area. An upper bound of 0.8440935944 is found.
plane-geometry  proof  rather-interesting  to-write-about  consider:representation 
4 weeks ago
Kelsey Brookes at the Jacob Lewis Gallery | fibonaccisusan
Kelsey Brookes current solo exhibition at the Jacob Lewis gallery is titled ” The Mathematics Underlying Art”. I was so happy to see that the Fibonacci Sequence is a major theme for these large scale paintings. Each square canvas is divided into thirteen (13 is a Fibonacci Number) wedges radiating from the center point. Then dots are made along each dividing line at intervals that correspond to the Fibonacci Sequence.
generative-art  rather-interesting  to-follow 
4 weeks ago
Evolution of metazoan morphological disparity | PNAS
We attempt to quantify animal “bodyplans” and their variation within Metazoa. Our results challenge the view that maximum variation was achieved early in animal evolutionary history by nonuniformitarian mechanisms. Rather, they are compatible with the view that the capacity for fundamental innovation is not limited to the early evolutionary history of clades. We perform quantitative tests of the principal hypotheses of the molecular mechanisms underpinning the establishment of animal bodyplans and corroborate the hypothesis that animal evolution has been permitted or driven by gene regulatory evolution.
developmental-biology  biology  rather-interesting  clustering  looking-to-see  to-write-about  consider:feature-discovery 
4 weeks ago
net.wars: We know where you should live
John Hancock doesn't mention it, but there are some obvious caveats about these figures. First of all, the program began in 2015. How does the company have data showing its users live so much longer? Doesn't that suggest that these users were living longer *before* they adopted the program? Which leads to the second point: the segment of the population that has wearable fitness trackers and smartphones tends to be more affluent (which tends to favor better health already) and more focused on their health to begin with (ditto). I can see why an insurance company would like me to "engage with" its program twice a day, but I can't see why I would want to. Insurance companies are not my *friends*.
corporatism  privacy  science-fiction  dystopia-is-you-know-just-normal  actuarial-statistics 
4 weeks ago
Evil Online and the Moral Fog | Practical Ethics
I see Evil Online as in the same tradition as Hannah Arendt’s crucially important book The Banality of Evil, which attempted to explain and characterize the behaviour of apparently ‘ordinary’ people – rather than probable psychopaths like Himmler – in the Holocaust. As Cocking and van den Hoven note, whether their idea of a moral fog is a development of the banality thesis or something entirely new doesn’t matter much, since even if it is a development they are taking it further and using the idea of a moral fog to elucidate the way that the online environment we are in can make us insensitive to moral facts we’re otherwise perfectly capable of recognizing. Certainly the particular mechanisms of totalitarianism identified by Arendt aren’t straightforwardly going to explain evil online, but the general issues at stake do have similarities. How is it that Eichmann and the non-psychopathic perpetrators of evil online come to ignore their duty, or arrive at such a distorted view of what duty requires?

The book is also in some ways analogous to Thomas Hobbes’s Leviathan, first published in 1651, in which Hobbes tries to explain how the natural state of human beings is amoral – a war of all against all – and how morality can be seen as a human creation enabling us to escape that state and build a civilization. The online world is something like a state of nature, but the difference between the Hobbesian situation and our own is that we already have a morality. The puzzle is how to disperse the fog, and it is a puzzle we need urgently to think about before it is too late and the fog begins to thicken and drift even further than it is already doing from the online into the real world.
cultural-dynamics  ethics  internet  politics  to-read 
4 weeks ago
[1802.06764] Stability of items: an experimental test
The words of a language are randomly replaced in time by new ones, but long since it was observed that words corresponding to some items (meanings) are less frequently replaced then others. Usually, the rate of replacement for a given item is not directly observable, but it is inferred by the estimated stability which, on the contrary, is observable. This idea goes back a long way in the lexicostatistical literature, nevertheless nothing ensures that it gives the correct answer. The family of Romance languages allows for a direct test of the estimated stabilities against the replacement rates since the protolanguage (Latin) is known and the replacement rates can be explicitly computed. The output of the test is threefold: first, we prove that the standard approach which tries to infer the replacement rates trough the estimated stabilities is sound; second, we are able to rewrite the fundamental formula of Glottochronology for a non universal replacement rate (a rate which depends on the item), third, we give indisputable evidence that the stability ranking is far to be the same for different families of languages. This last result is also supported by comparison with the Malagasy family of dialects. As a side result we also provide some evidence that Vulgar Latin and not Late Classical Latin is at the root of modern Romance languages.
linguistics  chronology  rather-interesting  simulation  statistics  heterogeneity  it's-more-complicated-than-you-think  to-write-about  cladistics 
4 weeks ago
9 Collections
The collection classes form a loosely-defined group of general-purpose subclasses of Collection and Stream. The group of classes that appears in the “Blue Book” 1 contains 17 subclasses of Collection and 9 subclasses of Stream, for a total of 28 classes, and had already been redesigned several times before the Smalltalk-80 system was released. This group of classes is often considered to be a paradigmatic example of object-oriented design.
languages  Smalltalk  classes  computer-science  nudge  consider:robustness  to-write-about 
4 weeks ago
On civil war – An und für sich
The last time our country was on the brink of civil war, the slavers had a stranglehold on institutional power and the terms of debate and yet continually viewed themselves as oppressed victims — and as soon as an opposition president took office, they decided to blow up the country rather than accept his victory. Like contemporary Democrats, Lincoln was conciliatory to a fault, but the slavers would not take yes for an answer. Lincoln was, of course, actually able to become president in the first place despite the slavers’ opposition. If a Democrat won the 2020 election, would they even be able to take office? Would Republicans control enough state-level governments to steal the Electoral College outright? And then what?
politics  Civil-War 
4 weeks ago
[1512.04722] Visible lattice points in random walks
We consider the possible visits to visible points of a random walker moving up and right in the integer lattice (with probability α and 1−α, respectively) and starting from the origin.
We show that, almost surely, the asymptotic proportion of strings of k consecutive visible lattice points visited by such an α-random walk is a certain constant ck(α), which is actually an (explicitly calculable) polynomial in α of degree 2⌊(k−1)/2⌋. For k=1, this gives that, almost surely, the asymptotic proportion of time the random walker is visible from the origin is c1(α)=6/π2, independently of α.
random-walks  rather-interesting  combinatorics  probability-theory  simulation  nudge-targets  number-theory  representation  to-simulate  consider:feature-discovery 
4 weeks ago
[1711.05793] On the proximity of large primes
By a sphere-packing argument, we show that there are infinitely many pairs of primes that are close to each other for some metrics on the integers. In particular, for any numeration basis q, we show that there are infinitely many pairs of primes the base q expansion of which differ in at most two digits. Likewise, for any fixed integer t, there are infinitely many pairs of primes, the first t digits of which are the same. In another direction, we show that, there is a constant c depending on q such that for infinitely many integers m there are at least cloglogm primes which differ from m by at most one base q digit.
number-theory  Hamming-distance  proof  consider:looking-to-see  consider:generative-algorithm  nudge-targets 
4 weeks ago
[1710.08403] Constrained ternary integers
An integer n is said to be ternary if it is composed of three distinct odd primes. In this paper, we asymptotically count the number of ternary integers n≤x with the constituent primes satisfying various constraints. We apply our results to the study of the simplest class of (inverse) cyclotomic polynomials that can have coefficients that are greater than 1 in absolute value, namely to the nth (inverse) cyclotomic polynomials with ternary n. We show, for example, that the corrected Sister Beiter conjecture is true for a fraction ≥0.925 of ternary integers.
number-theory  cryptography  prime-numbers  elliptic-curves  nudge-targets  to-understand 
4 weeks ago
[1708.03563] On the discriminator of Lucas sequences
"Thus the situation is more weird than Shallit expected and this is confirmed by Theorem 1."


We consider the family of Lucas sequences uniquely determined by Un+2(k)=(4k+2)Un+1(k)−Un(k), with initial values U0(k)=0 and U1(k)=1 and k≥1 an arbitrary integer. For any integer n≥1 the discriminator function k(n) of Un(k) is defined as the smallest integer m such that U0(k),U1(k),…,Un−1(k) are pairwise incongruent modulo m. Numerical work of Shallit on k(n) suggests that it has a relatively simple characterization. In this paper we will prove that this is indeed the case by showing that for every k≥1 there is a constant nk such that k(n) has a simple characterization for every n≥nk. The case k=1 turns out to be fundamentally different from the case k>1.
number-theory  sequences  conjecture  rather-interesting  nudge-targets  pattern-discovery  to-write-about  consider:looking-to-see 
4 weeks ago
Slippery Characters | Laura Browder | University of North Carolina Press
In the 1920s, black janitor Sylvester Long reinvented himself as Chief Buffalo Child Long Lance, and Elizabeth Stern, the native-born daughter of a German Lutheran and a Welsh Baptist, authored the immigrant's narrative I Am a Woman--and a Jew; in the 1990s, Asa Carter, George Wallace's former speechwriter, produced the fake Cherokee autobiography, The Education of Little Tree. While striking, these examples of what Laura Browder calls ethnic impersonator autobiographies are by no means singular. Over the past 150 years, a number of American authors have left behind unwanted identities by writing themselves into new ethnicities.
Significantly, notes Browder, these ersatz autobiographies have tended to appear at flashpoints in American history: in the decades before the Civil War, when immigration laws and laws regarding Native Americans were changing in the 1920s, and during the civil rights era, for example. Examining the creation and reception of such works from the 1830s through the 1990s--against a background ranging from the abolition movement and Wild West shows to more recent controversies surrounding blackface performance and jazz music--Browder uncovers their surprising influence in shaping American notions of identity.
forgery  autobiographical  history  rather-interesting  literary-criticism  speaking-as  to-write-about 
4 weeks ago
CABINET // Deception as a Way of Knowing: A Conversation with Anthony Grafton
Anxiety about deception runs deep in the philosophical and religious traditions of Europe, and new techniques for mastering this fear mark episodes in the history of the modern world. Over the course of the nineteenth century, both the playfulness and the peril of deceit came to be distanced from the sphere of rational inquiry: the sciences ceased to have much use for legerdemain; metaphysicians lost interest in the theater. But it was not always so, as the conversation below with Anthony Grafton suggests. Grafton is the Henry Putnam University Professor of History at Princeton University and the author of a shelf of major works on the­ Renaissance, classical scholarship, ­and the history of science, including Forgers and Critics: Creativity and Duplicity in Western Scholarship (Princeton University Press, 1990).­ ­D. Graham Burnett, editor at Cabinet and also professor of history at Princeton, sat down with Grafton to discuss his work on deception and forgery­.
humanities  history  deception  forgery  rather-interesting  to-think-on  the-mangle-in-practice  mastery  mystery  reconfiguration 
4 weeks ago
Progressive Labels for Regressive Practices - Alfie Kohn
You see the pattern here. We need to ask what kids are being given to do, and to what end, and within what broader model of learning, and as decided by whom. If we allow ourselves to be distracted from those questions, then even labels with a proud progressive history can be co-opted to the point that they no longer provide reassurance about the practice to which the label refers.
pedagogy  corporatism  normalization  coopting  progressivism  rather-interesting 
4 weeks ago
[math/0408099] Tropical Mathematics
These are the notes for the Clay Mathematics Institute Senior Scholar Lecture which was delivered by Bernd Sturmfels in Park City, Utah, on July 22, 2004. The topic of this lecture is the ``tropical approach'' in mathematics, which has gotten a lot of attention recently in combinatorics, algebraic geometry and related fields. It offers an an elementary introduction to this subject, touching upon Arithmetic, Polynomials, Curves, Phylogenetics and Linear Spaces. Each section ends with a suggestion for further research. The bibliography contains numerousreferences for further reading in this field.
group-theory  mathematics  representation  combinatorics  rather-interesting  to-write-about 
5 weeks ago
TimeMachineEditor
TimeMachineEditor is a software for macOS that lets you change the default one-hour backup interval of Time Machine. You can change the interval or create a more sophisticated scheduling (see screenshots below).

This is useful if you don’t need to backup every hour and don’t want the performance penalty. This is also especially useful if you manipulate lots of data within one hour as you would spend the whole day backing up.
MacOS  utility  backup  to-do  dammit 
5 weeks ago
Quickly recognizing primes less than 100 | The Math Less Traveled
Recently, Mark Dominus wrote about trying to memorize all the prime numbers under . This is a cool idea, but it made me start thinking about alternative: instead of memorizing primes, could we memorize a procedure for determining whether a number under is prime or composite? And can we make it clever enough to be done relatively quickly? This does tie into my other recent posts about primality testing, but to be clear, it’s also quite different: I am not talking about a general method for determining primality, but the fastest method we can devise for mentally determining, by hook or by crook, whether a given number under is prime. Hopefully there are rules we can come up with which are valid for numbers less than —and thus make them easier to test—even though they aren’t valid for bigger numbers in general.
mathematical-recreations  number-theory  heuristics  nudge-targets  consider:looking-to-see  to-write-about 
5 weeks ago
The Policeman’s Beard is Algorithmically Constructed - 3:AM Magazine
The Policeman’s Beard is an aggressively egotistical book. Measuring 22.6 x 20.3 x 1.5 centimetres, it dwarfs many of its neighbours on the shelf. Its paper cover is bright red, with a doctored photograph of a man who occupies a sturdy frame as he glares at prospective readers. The book begs to be handled, while at the same time warning readers to approach with caution.

And caution is indeed warranted, for The Policeman’s Beard and Racter are puzzling. In some ways, Racter does adhere to the modern conception of authorship. As with any human writer, Racter’s code interacts with a world—albeit a limited world that has been consciously created by its programmers—as a source of information, and remixes content to create unique texts. Yet Racter is rigid, using fixed functions to complete a particular task. The program cannot interpret that which it produces and, indeed, not until a human interprets Racter’s output can it be assigned any cultural value.
generative-art  nanohistory  natural-language-processing  I-remember-it-well  the-mangle-in-practice  to-write-about  literary-criticism  computational-criticism  performative-writing 
5 weeks ago
[1804.03032] k-NN Graph Construction: a Generic Online Approach
Nearest neighbor search and k-nearest neighbor graph construction are two fundamental issues arise from many disciplines such as information retrieval, data-mining, machine learning and computer vision. Despite continuous efforts have been taken in the last several decades, these two issues remain challenging. They become more and more imminent given the big data emerges in various fields and has been expanded significantly over the years. In this paper, a simple but effective solution both for k-nearest neighbor search and k-nearest neighbor graph construction is presented. Namely, these two issues are addressed jointly. On one hand, the k-nearest neighbor graph construction is treated as a nearest neighbor search task. Each data sample along with its k-nearest neighbors are joined into the k-nearest neighbor graph by sequentially performing the nearest neighbor search on the graph under construction. On the other hand, the built k-nearest neighbor graph is used to support k-nearest neighbor search. Since the graph is built online, dynamic updating of the graph, which is not desirable from most of the existing solutions, is supported. Moreover, this solution is feasible for various distance measures. Its effectiveness both as a k-nearest neighbor construction and k-nearest neighbor search approach is verified across various datasets in different scales, various dimensions and under different metrics.
graph-theory  algorithms  to-understand  rather-interesting  computational-complexity  data-structures 
5 weeks ago
[1804.10962] Stress anisotropy in shear-jammed packings of frictionless disks
We perform computational studies of repulsive, frictionless disks to investigate the development of stress anisotropy in mechanically stable (MS) packings. We focus on two protocols for generating MS packings: 1) isotropic compression and 2) applied simple or pure shear strain γ at fixed packing fraction ϕ. MS packings of frictionless disks occur as geometric families (i.e. parabolic segments with positive curvature) in the ϕ-γ plane. MS packings from protocol 1 populate parabolic segments with both signs of the slope, dϕ/dγ>0 and dϕ/dγ<0. In contrast, MS packings from protocol 2 populate segments with dϕ/dγ<0 only. For both simple and pure shear, we derive a relationship between the stress anisotropy and dilatancy dϕ/dγ obeyed by MS packings along geometrical families. We show that for MS packings prepared using isotropic compression, the stress anisotropy distribution is Gaussian centered at zero with a standard deviation that decreases with increasing system size. For shear jammed MS packings, the stress anisotropy distribution is a convolution of Weibull distributions that depend on strain, which has a nonzero average and standard deviation in the large-system limit. We also develop a framework to calculate the stress anisotropy distribution for packings generated via protocol 2 in terms of the stress anisotropy distribution for packings generated via protocol 1. These results emphasize that for repulsive frictionless disks, different packing-generation protocols give rise to different MS packing probabilities, which lead to differences in macroscopic properties of MS packings.
physics!  sandpiles  materials-science  simulation  rather-interesting  condensed-matter  phase-transitions  looking-to-see 
5 weeks ago
Tales from Underwater | Status 451
“If you’re wondering whether it feels a little weird to have had someone you don’t clearly remember being make potentially life-altering decisions about you, the answer is yes.”
essay  depression  cognition  the-mangle-is-coming-from-inside-the-house  philosophy  introspection  resonant  identifiable-in-the-extreme 
5 weeks ago
[1803.10908] Matrix Product Operators for Sequence to Sequence Learning
The method of choice to study one-dimensional strongly interacting many body quantum systems is based on matrix product states and operators. Such method allows to explore the most relevant, and numerically manageable, portion of an exponentially large space. It also allows to describe accurately correlations between distant parts of a system, an important ingredient to account for the context in machine learning tasks. Here we introduce a machine learning model in which matrix product operators are trained to implement sequence to sequence prediction, i.e. given a sequence at a time step, it allows one to predict the next sequence. We then apply our algorithm to cellular automata (for which we show exact analytical solutions in terms of matrix product operators), and to nonlinear coupled maps. We show advantages of the proposed algorithm when compared to conditional random fields and bidirectional long short-term memory neural network. To highlight the flexibility of the algorithm, we also show that it can readily perform classification tasks.
representation  machine-learning  to-understand  matrices  quantum-computing  classification  algorithms 
5 weeks ago
Coder-Physicists Are Simulating the Universe to Unlock Its Secrets | Quanta Magazine
These small, faint galaxies have always presented problems. The “missing satellite problem,” for instance, is the expectation, based on standard cold dark matter models, that hundreds of satellite galaxies should orbit every spiral galaxy. But the Milky Way has just dozens. This has caused some physicists to contemplate more complicated models of dark matter. However, when Hopkins and colleagues incorporated realistic superbubbles into their simulations, they saw many of those excess satellite galaxies go away. Hopkins has also found potential resolutions to two other problems, called “cusp-core” and “too-big-to-fail,” that have troubled the cold dark matter paradigm.
simulation  looking-to-see  astronomy  rather-interesting  to-write-about  the-mangle-in-practice  (totally) 
5 weeks ago
In Defense of Hoaxes - Justin Erik Halldór Smith
Whatever. Everyone's playing their assigned roles. But what I wanted to speak to here is the question of hoaxes in general. Quite apart from whether I think “Sokal Squared” has accomplished what its authors claim, I confess I am astounded, though I really should not be by now, by the moralism and the piety about rules and procedures that so many academics are expressing, as if hoaxing were always unethical and lacking in any potential salutary effects. These academics seem entirely unaware of the distinguished history of hoaxing, and to assume that it dates back no earlier than Sokal. They seem never to have read, e.g., Anthony Grafton on the importance of playful deception in the learned culture of Italian humanism. They seem unaware of the rich and fascinating 19th-century genre of the “mystification.” They seem unaware of the often high-minded theoretical ambitions of documentary metafiction and of the vague gradations between this broad genre of writing and outright fraud. They do not know about the French fraudster Denis Vrain-Lucas, who was eventually arrested, in 1869, for having passed off numerous falsified letters as authentic documents. Vrain-Lucas continued to defend himself, from prison, on the grounds that he had breathed new life into the carcass of history by making past characters, including Newton, Galileo, Vercingétorix, and Jesus Christ, more interesting than they actually were. They do not know about Ken Alder's ingenious piece in Critical Inquiry in 2004, which was a purported translation from the French of a prison letter by Vrain-Lucas. I learned more about the history and historiography of science from Alder's piece than from any other single text I could cite. 
hoaxes  academic-culture  politics  history-is-a-feature-not-a-bug  to-write-about  metafiction  paratexts 
6 weeks ago
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