'Mathwashing,' Facebook and the zeitgeist of data worship

maths
math
mathwashing
data
big-data
algorithms
machine-learning
bias
facebook
fred-benenson

5 weeks ago by jm

Fred Benenson: Mathwashing can be thought of using math terms (algorithm, model, etc.) to paper over a more subjective reality. For example, a lot of people believed Facebook was using an unbiased algorithm to determine its trending topics, even if Facebook had previously admitted that humans were involved in the process.

5 weeks ago by jm

_What We Know About Spreadsheet Errors_ [paper]

business
coding
maths
excel
spreadsheets
errors
formulas
error-rate

october 2015 by jm

As we will see below, there has long been ample evidence that errors in spreadsheets are pandemic. Spreadsheets, even after careful development, contain errors in one percent or more of all formula cells. In large spreadsheets with thousands of formulas, there will be dozens of undetected errors. Even significant errors may go undetected because formal testing in spreadsheet development is rare and because even serious errors may not be apparent.

october 2015 by jm

The Pixel Factory

september 2015 by jm

amazing slideshow/WebGL demo talking about graphics programming, its maths, and GPUs

maths
graphics
webgl
demos
coding
algorithms
slides
tflops
gpus
september 2015 by jm

A higher order estimate of the optimum checkpoint interval for restart dumps

june 2015 by jm

tl;dr:

dumping
periodic-tasks
scheduling
frequency
maths
optimal
interval
checkpointing
the bottom line is as follows:

If the time it takes to create a dump, δ < M/2 then use τopt = √(2δM) – δ

Otherwise (it takes longer than M/2 to create a dump), just use τopt = M.

june 2015 by jm

the "Unknown Pleasures" cover, emulated in Mathematica

The entire blog at http://intothecontinuum.tumblr.com/ is pretty great. Lots of nice mathematical animated GIFs, accompanied by Mathematica source and related ponderings.
maths
gifs
animation
art
unknown-pleasures
mathematica
cp-1919
pulsars
astronomy
joy-division
waterfall-plots
cambridge
blogs

december 2014 by jm

In July 1967, astronomers at the Cavendish Laboratory in Cambridge, observed an unidentified radio signal from interstellar space, which flashed periodically every 1.33730 seconds. This object flashed with such regularity that it was accurate enough to be used as a clock and only be off by one part in a hundred million.

It was eventually determined that this was the first discovery of a pulsar, CP-1919. This is an object that has about the same mass as the Sun, but is the size of the San Francisco Bay at its widest (~20 kilometers) that is rotating so fast that its emitting a beam of light towards Earth like a strobing light house! Pulsars are neutron stars that are formed from the remnants of a massive star when it experiences stellar death.

A hand drawn graph plotted in the style of a waterfall plot, in the Cambridge Encyclopedia of Astronomy, later became renown for its use on the cover of the album "Unknown Pleasures" by 1970s English band Joy Division.

The entire blog at http://intothecontinuum.tumblr.com/ is pretty great. Lots of nice mathematical animated GIFs, accompanied by Mathematica source and related ponderings.

december 2014 by jm

'Addressing the rebalancing problem in bike-sharing systems' [paper]

Timely -- here's what Dublin Bikes looked like this morning: https://twitter.com/jmason/status/503828246086295552

(via Andrew Caines)
cycling
bike-sharing
borisbikes
dublinbikes
rebalancing
fleet
availability
optimization
maths
papers
toread
algorithms

august 2014 by jm

Many of the bike-sharing systems introduced around the world in the past 15 years have the same problem: Riders tend to take some routes and not others. As a result, the bikes tend to collect in a few places, which is a drag for users and a costly problem for the operators, who "rebalance" the system using trucks that take bikes from full stations to empty ones. Now, scientists are coming up with special algorithms to improve this process. One of them, developed by scientists at the Vienna University of Technology and the Austrian Institute of Technology, is now being tested in Vienna's bike-sharing system; another, developed at Cornell University, is already in use in New York City.

Timely -- here's what Dublin Bikes looked like this morning: https://twitter.com/jmason/status/503828246086295552

(via Andrew Caines)

august 2014 by jm

Nassim Taleb: retire Standard Deviation

january 2014 by jm

Use the mean absolute deviation [...] it corresponds to "real life" much better than the first—and to reality. In fact, whenever people make decisions after being supplied with the standard deviation number, they act as if it were the expected mean deviation.'

Graydon Hoare in turn recommends the median absolute deviation. I prefer percentiles, anyway ;)

statistics
standard-deviation
stddev
maths
nassim-taleb
deviation
volatility
rmse
distributions
Graydon Hoare in turn recommends the median absolute deviation. I prefer percentiles, anyway ;)

january 2014 by jm

East Texas Judge Says Mathematical Algorithms Can’t Be Patented, Dismisses Uniloc Claim Against Rackspace

march 2013 by jm

This seems pretty significant. Is the tide turning in the Texas Eastern District against patent trolls, at last? And does it establish sufficient precedent?

See https://news.ycombinator.com/item?id=5455869 for more discussion.

east-texas
patents
swpats
maths
patenting
law
judges
rackspace
linux
red-hat
uniloc-usa
floating-point

A federal judge has thrown out a patent claim against Rackspace, ruling that mathematical algorithms can’t be patented. The ruling in the Eastern Disrict stemmed from a 2012 complaint filed by Uniloc USA asserting that processing of floating point numbers by the Linux operating system was a patent violation.

Chief Judge Leonard Davis based the ruling on U.S. Supreme Court case law that prohibits the patenting of mathematical algorithms. According to Rackspace, this is the first reported instance in which the Eastern District of Texas has granted an early motion to dismiss finding a patent invalid because it claimed unpatentable subject matter.

Red Hat, which supplies Linux to Rackspace, provided Rackspace’s defense. Red Hat has a policy of standing behind customers through its Open Source Assurance program.

See https://news.ycombinator.com/item?id=5455869 for more discussion.

march 2013 by jm

The Mathematical Hacker

december 2012 by jm

'The trouble with the Lisp-hacker tradition is that it is overly focused on the problem of programming -- compilers, abstraction, editors, and so forth -- rather than the problems outside the programmer's cubicle. I conjecture that the Lisp-school essayists -- Raymond, Graham, and Yegge -- have not “needed mathematics” because they spend their time worrying about how to make code more abstract. This kind of thinking may lead to compact, powerful code bases, but in the language of economics, there is an opportunity cost.'

mathematics
coding
maths
essay
hackers
lisp
fortran
december 2012 by jm

Bayes' theorem ruled inadmissible in UK law courts

october 2011 by jm

Bayes' theorem, and 'similar statistical analysis', ruled inadmissible in UK law courts (via Tony Finch)

uk
law
guardian
via:fanf
bayes
maths
statistics
legal
october 2011 by jm

Kaprekar's constant

august 2010 by jm

'6174 .. is notable for the following property: Take any four-digit number, using at least two different digits. (Leading zeros are allowed.); Arrange the digits in ascending and then in descending order to get two four-digit numbers, adding leading zeros if necessary; Subtract the smaller number from the bigger number; Go back to step 2. The process will reach 6174 in at most 7 iterations'

6174
constants
cool
maths
mathematics
numbers
kaprekar
wow
from delicious
august 2010 by jm

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