jm + via:hn   23

Placebo effects are weak: regression to the mean is the main reason ineffective treatments appear to work
“Statistical regression to the mean predicts that patients selected for abnormalcy will, on the average, tend to improve. We argue that most improvements attributed to the placebo effect are actually instances of statistical regression.”
medicine  science  statistics  placebo  evidence  via:hn  regression-to-the-mean 
december 2015 by jm
Scaling Analytics at Amplitude
Good blog post on Amplitude's lambda architecture setup, based on S3 and a custom "real-time set database" they wrote themselves.

antirez' comment from a Redis angle on the set database: http://antirez.com/news/92

HN thread: https://news.ycombinator.com/item?id=10118413
lambda-architecture  analytics  via:hn  redis  set-storage  storage  databases  architecture  s3  realtime 
august 2015 by jm
Javascript Acid Machine
a 303 and an 808 (correction: apparently more like a 909) in your browser. this is deadly
acid  303  music  javascript  hacks  via:hn  techno 
march 2015 by jm
Why we run an open source program - Walmart Labs
This is a great exposition of why it's in a company's interest to engage with open source. Not sure I agree with 'engineers are the artists of our generation' but the rest are spot on
development  open-source  walmart  node  coding  via:hn  hiring 
february 2015 by jm
Warning: Do NOT use my mirrors services until I have reviewed the situation
Things hotting up in TOR-land.
Until I have had the time and information available to review the
situation, I am strongly recommending my mirrors are not used under
any circumstances. If they come back online without a PGP signed
message from myself to further explain the situation, exercise extreme
caution and treat even any items delivered over TLS to be potentially
hostile.
tor  privacy  crackdown  anonymity  seizures  crypto  via:hn 
december 2014 by jm
Stupid Projects From The Stupid Hackathon
Amazing.
iPad On A Face by Cheryl Wu is a telepresence robot, except it’s a human with an iPad on his or her face.
funny  hacking  stupid  hackathons  ipad-on-a-face  telepresence  hacks  via:hn 
november 2014 by jm
How I created two images with the same MD5 hash
I found that I was able to run the algorithm in about 10 hours on an AWS large GPU instance bringing it in at about $0.65 plus tax.


Bottom line: MD5 is feasibly attackable by pretty much anyone now.
crypto  images  md5  security  hashing  collisions  ec2  via:hn 
november 2014 by jm
Breaking Spotify DRM with PANDA
Reverse engineering a DRM implementation, by instrumenting a VM and performing entropy/compressability analysis on function call inputs and outputs. Impressive
reversing  spotify  drm  panda  vm  compression  entropy  compressability  qemu  via:hn 
july 2014 by jm
SSD shadiness: Kingston and PNY caught bait-and-switching cheaper components after good reviews | ExtremeTech
Imagine buying a high-end Core i7 or AMD CPU, opening the box, and finding a midrange part sitting there with an asterisk and the label “Performs Just Like Our High End CPU In Single-Threaded SuperPi!”
ssd  storage  hardware  sketchy  kingston  pny  bait-and-switch  components  vendors  via:hn 
june 2014 by jm
Rope-core memory
as used in the Apollo guidance computer systems -- hand-woven by "little old ladies". Amazing
core-memory  memory  rope-core  guidance  apollo  space  nasa  history  1960s  via:hn 
april 2014 by jm
Why Mt. Gox is full of shit
leading Bitcoin exchange "Magic The Gatherine Online Exchange" turns out to suffer from crappy code, surprise:
why does Mt. Gox experience this issue? They run a custom Bitcoin daemon, with a custom implementation of the Bitcoin protocol. Their implementation, against all advice, does rely on the transaction ID, which makes this attack possible. They have actually been warned about it months ago by gmaxwell, and have apparently decided to ignore this warning. In other words, this is not a vulnerability in the Bitcoin protocol, but an implementation error in Mt. Gox' custom Bitcoin software.


The rest of the article is eyeopening, including the MySQL injection vulnerabilities and failure to correctly secure a Prolexic-defended server.

https://news.ycombinator.com/item?id=7211286 has some other shocking reports of Bitcoin operators being incompetent, including 'Bitomat, the incompetent exchange that deleted their own [sole] amazon instance accidentally which contained all their keys, and thus customer funds'. wtfbbq
mtgox  security  bitcoin  standards  omgwtfbbq  via:hn  bitomat 
february 2014 by jm
Fat Tails
Nice d3.js demo of the fat-tailed distribution:
A fat-tailed distribution looks normal but the parts far away from the average are thicker, meaning a higher chance of huge deviations. [...] Fat tails don't mean more variance; just different variance. For a given variance, a higher chance of extreme deviations implies a lower chance of medium ones.
dataviz  via:hn  statistics  visualization  distributions  fat-tailed  kurtosis  d3.js  javascript  variance  deviation 
july 2013 by jm
21 graphs that show America’s health-care prices are ludicrous
Excellent data, this. I'd heard a few of these prices, but these graphs really hit home. $26k for a caesarean section at the 95th percentile!? talk about out of control price gouging.
healthcare  costs  economics  us-politics  world  comparison  graphs  charts  data  via:hn  america 
march 2013 by jm
Timelike 2: everything fails all the time
Fantastic post on large-scale distributed load balancing strategies from @aphyr. Random and least-conns routing comes out on top in his simulation (although he hasn't yet tried Marc Brooker's two-randoms routing strategy)
via:hn  routing  distributed  least-conns  load-balancing  round-robin  distcomp  networking  scaling 
february 2013 by jm
Heroku finds out that distributed queueing is hard
Stage 3 of the Rap Genius/Heroku blog drama. Summary (as far as I can tell): Heroku gave up on a fully-synchronised load-balancing setup ("intelligent routing"), since it didn't scale, in favour of randomised queue selection; they didn't sufficiently inform their customers, and metrics and docs were not updated to make this change public; the pessimal case became pretty damn pessimal; a customer eventually noticed and complained publicly, creating a public shit-storm.

Comments: 1. this is why you monitor real HTTP request latency (scroll down for crazy graphs!). 2. include 90/99 percentiles to catch the "tail" of poorly-performing requests. 3. Load balancers are hard.

http://aphyr.com/posts/277-timelike-a-network-simulator has more info on the intricacies of distributed load balancing -- worth a read.
heroku  rap-genius  via:hn  networking  distcomp  distributed  load-balancing  ip  queueing  percentiles  monitoring 
february 2013 by jm
Why did infinite scroll fail at Etsy?
'A/B testing must be done in a modularized fashion. The “fail” case he gave was when Etsy spent months developing and testing infinite scroll to their search listings, only to find that it had a negative impact on engagement.' [...] 'instead of having the goal of “test infinite scroll,” Etsy realized it needed to test each assumption separately, and this going forward is their game plan.'
usability  testing  design  etsy  ab-testing  test  modularization  via:hn 
january 2013 by jm
What Happens to Stolen Bicycles?
'Bike thievery is essentially a risk-free crime. If you were a criminal, that might just strike your fancy. If Goldman Sachs didn’t have more profitable market inefficencies to exploit, they might be out there arbitraging stolen bikes.'

Good summary, and I suspect a lot applies in Dublin too -- flea markets and vanloads of stolen bikes being sent to other cities for reselling.
via:hn  economics  crime  bikes  theft  goldman-sachs 
august 2012 by jm
satellite rescue abandoned due to patents
'SES and Lockheed Martin explored ways to attempt to bring the functioning [AMC-14] satellite into its correct orbital position, and subsequently began attempting to move the satellite into geosynchronous orbit by means of a lunar flyby (as done a decade earlier with HGS-1). In April 2008, it was announced that this had been abandoned after it was discovered that Boeing held a patent on the trajectory that would be required. At the time, a lawsuit was ongoing between SES and Boeing, and Boeing refused to allow the trajectory to be used unless SES dropped its case.' In. credible. http://www.spacedaily.com/reports/Boeing_Patent_Shuts_Down_AMC_14_Lunar_Flyby_Salvage_Attempt_999.html notes 'Industry sources have told SpaceDaily that the patent is regarded as legal "trite", as basic physics has been rebranded as a "process", and that the patent wouldn't stand up to any significant level of court scrutiny and was only registered at the time as "the patent office was incompetent when it came to space matters"', but still -- who'd want to go up in court against Boeing?
boeing  space  patenting  via:hn  funny  sad  lockheed-martin  ses  amc-14  business-process  patents 
may 2012 by jm
Hacker News | Ooops.
brilliant thread of epic "OMG WHAT HAVE I DONE" stories
fail  ouch  oops  via:hn  via:waxy  computers  software  rm-rf 
june 2011 by jm
Python Idioms and Efficiency Suggestions
will have to run this by our resident Pythonistas in work as a good set of guidelines
idioms  programming  python  reference  tips  via:hn 
june 2011 by jm
Dr. Neal Krawetz explains perceptual hashing
ie. TinEye and other "images like this one" search engines. nice explanation
algorithm  images  analysis  programming  dct  hashing  perceptual-hash  tineye  via:hn  image 
june 2011 by jm
gist: 782263 - How to redirect a running process' output to a file and logout
a nifty gdb hack; essentially dup()s a couple of files in /tmp in place of fd 1 and 2, then uses the bashism "detach" to nohup the running process
gdb  hacks  linux  process  shell  unix  via:hn  nifty  dup  detach  bash  from delicious
january 2011 by jm

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