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Andrew Reid
Works at NIST
Attended Queen's University
Lives in Washington DC
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Andrew Reid

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Debian announces LTS for Debian 6.0 "squeeze"!

For an enterprise sysadmin like me, this is a really nice option to have.  I'll be upgrading most of my systems anyways, to get at more recent functionality, but there are a few "back-end" systems that really just do very basic things. It's nice to have the option to defer their upgrade until it's needed for service or technical reasons, not for security policy reasons.

Thanks, guys!
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Nice new bit from +Scott Aaronson , most of which I at least feel like I should know.

It's a good rejoinder to those to would tell you that any given sequence of, say, coin flips, including all heads and "random" ones, occur with equal probability. While this is true, it's not relevant, and it doesn't help you distinguish fair coins from unfair ones.

My usual reply (when I reply) is to point out, rather imprecisely, that "random-looking" sequences quite obviously inhabit a large equivalence class, that there are lots of sequences that "look the same" as a generic sequence, but that the all-heads sequence is obviously special, relatively few sequences look like it.  This is the right idea, and the article makes it precise by introducing Kolmogorov complexity.

The discussion reminds me of a story I have heard about human perceptions of randomness -- some statistics instructor has his class create sequences of ones and zeros, and mixes them up with machine-generated pseudo-random sequenced. The story goes that the instructor can, with high reliability, distinguish human-generated sequences from machine-generated ones, because the human-generated ones tended not to have runs of ones or zeros -- they're "fair" on very short length scales -- whereas machine-generated ones often have quite long runs.

A cautionary tale about "looking random", and an endorsement of analytical tools, I think.
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Disaster averted, from 99percentinvisible.

The Citicorp Center, 601 Lexington Ave, New York, was built with a design flaw, leaving it vulnerable to collapse in high quartering winds. The flaw was discovered by an architecture student, Diane Hartley, who notified the building owners. They reinforced the building, and saved the day, but Diane Hartley didn't find out the impact she'd had until she saw a TV special about it.

Like a lot of disasters, averted and not, there's a chain of unusual circumstances and inappropriate decisions that added up to the risk.

Apparently their fix worked, the thing survived Sandy.
When it was built in 1977, Citicorp Center  (later renamed Citigroup Center, now called 601 Lexington) was, at 59 stories, the seventh-tallest building in the world. You can pick it out of the New ...
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The Computational Redshift, quantified.

The "computational redshift" was a metaphor used in a talk I saw several years ago by  Jack Dongarra (he of the Top500 project) to describe the increasing importance of memory localization and cache coherency in controlling performance.

In the old days, computers just had registers, memory, and maybe hard drives, and the ratio of the fastest data retrieval to the slowest was maybe two or three orders of magnitude.

As we can see in this chart, there's quite a span nowadays. Main memory access is already two orders of magnitude slower than a CPU cycle. The chart doesn't show timing for NFS file operations (probably the slowest data-retrieval operations that commonly occur on systems I'm familiar with), but they'd be on TCP time-scales of tens of milliseconds,  about seven orders of magnitude slower than a CPU cycle.

h/t +Aleatha Parker-Wood 
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1988: Page 125 and on in Danny Hillis' thesis: 
"New Computer Architectures and their Relation to Physics; or, Why Computer Science is No Good "
http://dspace.mit.edu/bitstream/handle/1721.1/14719/18524280.pdf?sequence=1
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Interesting take on what the fallout from Heartbleed should be, advocating a PGP-based peer-to-peer web of trust, instead of hierarchical chains of trust from an authority.
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Andrew Reid

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Well, this is very disappointing.

I guess we didn't make ourselves clear when we did this: https://petitions.whitehouse.gov/response/reaffirming-white-houses-commitment-net-neutrality
 
The worst possible news.
Everyone should fight this.
ISPs could charge for improved access as long as they don't block Web services.
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A nice reflection on US naturalization from one of the guys at CT.

My experiences with USCIS were better than his, although I did have my share of odd conversations with Customs and Border Protection, uncertain where it was going, confident I hadn't broken any rules, and keenly aware of their broad discretionary authority.

The most remarkable part of the ceremony, or rather the aftermath, for me was that there was a table right outside the courtroom where new citizens could register to vote, and have it take effect immediately. Replacing one's "green card" with a voter registration card was, for me, a distinctly pleasant experience.

My other noteworthy recollection was that, having the rest of the day free, I decided to head over to the Social Security office to get a new card, since I still had my old one from the J-visa days, with the "Valid for work only with INS approval" wording on it. Turned out the Social Security office didn't have my naturalization in their computer, and so could not issue me a new card yet, though they did admire my freshly-issued Certificate of Naturalization.
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Another fun map, the 4,871,270 census blocks with zero population in 2010. This doesn't mean nobody is there, but it does mean nobody lives there. The usual east-west divide of US population-density maps is evident.

Some additional context from GGW here: http://greatergreaterwashington.org/post/22533/another-way-to-see-the-us-map-of-where-nobody-lives/
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I wonder why North Dakota jumps out.  Some kind of state-specific systematic measuring error?  Or is there just something about it that creates lots of zero population pockets?  I can't imagine it is purely driven by geography.
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Today's bike route. This is one of the "normal" loops, it's long, and it has a couple of bail-out points, it comes close to the Grosvenor metro station around mile 13, and downtown Bethesda metro around mile 17. I didn't bail out today, though, I made it all the way around.

It's mostly multi-use paths, and the area around mile 17 requires careful attention to strollers, toddlers, and dogs, all of which have high interaction cross-sections. Everybody's pretty nice, so it generally works well.
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So here's an interesting cloud-storage hypothetical: Suppose you're a cloud storage service, and you do file deduplication, so that you only have to store one copy of each file, no matter how many of your users want a hosted copy. Suppose, further, that you allow users to publish links to content they have hosted with you.

You get a DMCA take-down request for some file shared by a user, which you honor. You know, because of your de-duplication scheme, and without necessarily knowing the contents of the file, that other users are also sharing the same file. Should you take down their public links also, and furthermore, prevent anyone with a copy of this file from publishing a link to it?

Numerous edge-case scenarios leap to mind:

Suppose I am a content owner, and have my content in the service, where I legally share it. I see an unauthorized share from the same service of my content, issue a DMCA take-down request, which legally applies to the pirate, but not to me. Does my legal sharing capability go away?

What about erroneous DMCA take-downs? Suppose Alice and I are both sharing content, but Alice gets an incorrect DMCA take-down request, which the service honors. Alice doesn't care, and does not contest the take-down. Meanwhile, my ability to legally share the file on the service is revoked. I am not the target of the take-down, but I've been hurt by it, can I contest it?

These questions are (rather obviously) motivated by the link below, which, I hasten to add, is a thread spun out from a single unconfirmed tweet.
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Have him in circles
70 people
Chris McClelland's profile photo
Dave Kary's profile photo
Nick Alcock's profile photo
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Work
Occupation
Scientific computing
Employment
  • NIST
    Scientific computing, present
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Currently
Washington DC
Previously
Canada - Calgary - Vancouver - Chicago
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Clever. Maybe clever enough.
Introduction
I studied computer science and physics at UBC, and have never really let go of either. I read a lot. Geeky, but not in a debilitating way.
Bragging rights
I know how much wood a woodchuck would chuck, but I'm not telling.
Education
  • Queen's University
    Physics, 1989 - 1994
  • University of British Columbia
    Physics, 1986 - 1989
  • University of British Columbia
    Physics and Computer Science, 1982 - 1986
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Male