HNHacker News
TopNewBestAskShowJobs

alepper

385 karma · joined February 28, 2013

submissionscomments
alepper··on KiCad: A commitment to freedom
Does this definitely extend to UK academics? They mention a .edu address is required, and I didn't hear back after applying with a .ac.uk address.
alepper··on The researcher programmer, a new species? (2012)
If you're based in the UK and interested in research software, you might want to look into 'The UK Community of Research Software Engineers'[1] and The Software Sustainability Institute[2]. From what I've seen, the latter in particular are exploring pragmatic ways to make software engineering more compatible with the expectations (e.g. citations) of academic employers.

[1] http://www.rse.ac.uk [2] http://www.software.ac.uk

alepper··on GaugeMap: Thousands of river gauges, each with a Twitter account
I'm looking at something similar at the moment, but in agricultural areas where line-of-sight is inhibited only by foliage and terrain. For my purpose, it's OK to collect an SD card every so often, but I've toyed with the idea of an ESP8266 and a directional antenna to e.g. a mobile broadband router, probably again with an antenna upgrade.

Earlier today, I found [1] which - amongst other things which you might be interested in - calls out a venture [2] to establish a network of 'citizen scientist' type flood sensors across the UK. Their scheme looks to be a network of radio-to-Internet gateways which support a number of independently-deployed sensor nodes.

[1] http://oomlout.co.uk/blogs/news/81763329-an-overview-of-ardu... [2] http://flood.network/

alepper··on On the orientation of Roman towns in Italy (2007) [pdf]
> I hope the published version in 2008 had it

The published version has headings: Latitude, Latin name, Modern name and date of Roman foundation, Axis, Amplitude at solstice, Published research. Still no map, though.

alepper··on C++ concepts support merged into GCC trunk
Constraints on template types are useful outside of metaprogramming proper. For example, the standard library already specifies classes of iterators dependent on e.g. the direction(s) in which they may be advanced.
alepper··on A deep look at BIND9 CVE-2015-5477
n.b. it's a double-pointer. The /called/ code probably allocates a dns_name_t itself, updating the /callee's/ pointer. If the callee's pointer isn't NULL, there's a chance overwriting it will cause a memory leak (as the caller may no longer have a reference to whatever it was pointing to). The comment acknowledges that it's perhaps unnecessarily strict.
alepper··on Intel 80386 Reference Programmer's Manual
I got a free copy of the lot back around 2003, but when I looked recently they've officially switched to printing on demand (priced at ~cost) via Lulu. I first got them for hobbyist operating system development - their residual utility there should remain high for a while. Plus, bookshelf cred!

http://www.intel.co.uk/content/www/uk/en/processors/architec...

alepper··on Computational Hydrographic Printing [video]
From the paper[1], it sounds like the same linear motion with the film wrapping around to the top:

    > The sphere is dipped with
    > its north pole pointing downward. The maximum error on the
    > northern hemisphere is within 2mm. However, near its south pole
    > the error is much larger (about 5mm). This is because after the
    > water surface passes the sphere’s equator, the film gets stretched
    > largely, and near the south pole the relative angle between the
    > water surface and the object surface approaches to 180◦, leading
    > to an ill-posed boundary condition for our simulation (recall
    > Equation (1), when θ ≈ 180◦).
You can see the potential for a similar wraparound even on e.g. the mask dips.

[1] http://www.kunzhou.net/2015/hydrographics.pdf

alepper··on Pure Python Vim clone
You might find (Typed) Racket interesting - it offers the features you mention, and is a delight to work with.
alepper··on New GPU Optimized EC2 G2 Instance, the G2.8xlarge
I have this kicking around from some experiments a month or two ago:

    sudo apt-get update
    sudo apt-get install build-essential linux-image-extra-virtual
    sudo reboot
    echo options nouveau modeset=0 | sudo tee -a /etc/modprobe.d/nouveau-kms.conf
    cat > /etc/modprobe.d/blacklist-nouveau.conf
    blacklist nouveau
    blacklist lbm-nouveau
    options nouveau modeset=0
    alias nouveau off
    alias lbm-nouveau off
    <Ctrl+D>
    sudo update-initramfs -u
    sudo reboot
    sudo apt-get install linux-headers-$(uname -r)
    wget http://uk.download.nvidia.com/XFree86/Linux-x86_64/346.35/NVIDIA-Linux-x86_64-346.35.run
    chmod +x NVIDIA-Linux-x86_64-346.35.run
    sudo ./NVIDIA-Linux-x86_64-346.35.run
    nvidia-smi -q | less
This is obviously not production-ready, and is heavily cribbed from online (I couldn't quickly re-find where) but is good enough if you just want to play.

EDIT: I think this was the original: http://ubuntuhandbook.org/index.php/2015/01/install-nvidia-3...

alepper··on How to generate a double-precision floating-point number in [0, 1] uniformly
You're right, sorry. I responded to 'why round?' but missed that comment.
alepper··on How to generate a double-precision floating-point number in [0, 1] uniformly
The clue's here:

> What is the `uniform' distribution we want, anyway? It is obviously not the uniform discrete distribution on the finite set of floating-point numbers in [0, 1] -- that would be silly. For our `uniform' distribution, we would like to imagine[*] drawing a real number in [0, 1] uniformly at random, and then choosing the nearest floating-point number to it.

Because of the logarithmic representation, there are as many floating point numbers between .25 and .5 as there are between .5 and 1. If you uniformly sample numbers with an exact, finite floating point representation then you don't get something that 'looks like' a uniform distribution of real numbers in [0, 1] -- which is more likely what was wanted.

alepper··on The Lost Art of C Structure Packing
No, the standard requires they appear in their order of declaration.
alepper··on How Your Camera Works
Correct link: http://graphics.stanford.edu/projects/camera-2.0/
alepper··on Triple-E Ship Leaves Port With World Record Load
Relatedly, 'The Box: How the Shipping Container Made the World Smaller and the World Economy Bigger' is a great little book. I don't see sense in retreading existing reviews, but I think it would offer something of interest for many in this crowd.
alepper··on Fail2ban security update
http://www.routeviews.org provides access to live and snapshot BGP data.
alepper··on Euclid: The Game
From the icons, it looks like this may be using Geogebra[1] under the hood. It's a really polished little tool for exploring geometry.

[1] http://www.geogebra.org/cms/en/

alepper··on Corecursion
Try sketching the call graph of e.g. fibonacci 5.
alepper··on Parallax effect using motion detection
I'm curious - it seems a little around-the-houses to have to use an approximation to erf when it's not obviously relevant. Why not just use an alternative sigmoid (e.g. the logistic function) or whatever the trigonometric solution falls out to be if you model it as a 'real' slewing or rotation motion around the scene?
alepper··on Understanding IP, TCP, and HTTP
Julia Evans at http://jvns.ca has a distinctive style that I enjoy.
alepper··on Why I'm Done With Social Media Buttons
> Does anyone remember what it was called?

Accelerators? http://ie.microsoft.com/activities/en-en/Default.aspx

alepper··on IPv6 domain readiness tester
Looks like: IPv6 addresses for NS (nameserver) and MX (mail exchange) records, and root and www subdomain. Looks to check DNS responds to queries over IPv6, too. Easy mode to get at least four stars: enable IPv6 with a free Cloudflare account.
alepper··on Show HN: Ridiculously cheap bulk geocoding
I used it to take a contact database for a series of seminars around the country and allocate participants to the geographically-appropriate venue.
alepper··on I worked on the US drone program. The public should know what really goes on
300,000,000 / 7,000,000,000 = 3 / 70, or a little less than half (3.5 / 70) of 10% (7 / 70). About 4%.
alepper··on PS4's LLVM-based Developer Toolchain [pdf]
Slide 13. TL;DR: From Sony, yes - as well as an independent third party toolchain.
alepper··on P = NP [pdf]
Presumably it was done this way to avoid the duplicate filter spotting that the same article was submitted under the other URL 11 hours ago: https://news.ycombinator.com/item?id=6846228
alepper··on Ansible 1.4 released
I don't want to hijack this thread, but I've found parameterized roles fit my use case perfectly. However, a couple related things caught me out earlier tonight: both the apt_key 'file' parameter, and 'with_file' seem to ignore the roles search paths. I have an apt role which handles installing the package keys, adding and updating repositories, and installing a list of packages. Passing e.g. 'nginx.key' from the nginx role wouldn't work, as they looked only in roles/apt/tasks rather than roles/*/files as I expected. Passing a full path worked. (If I remember correctly! I'm a little hazy on the exact details now, although if this isn't as expected I can do some legwork tomorrow and raise a bug.)

Thanks very much!

alepper··on Empty F-16 jet tested by Boeing and US Air Force
Peculiar - an earlier revision of the article did mention this. Then again, it also lacked the Campaign's comment at that time.
alepper··on LinkedIn sued by users who say it hacked their e-mail accounts
If I click 'see more' under the 'people you may know' list on the homepage, fully half of the eight people above the fold are without LinkedIn accounts. These include family members who I can be certain don't have accounts. I assume clicking 'add to network' (rather than the 'connect' for those who do have accounts) would generate an invitation to join LinkedIn.
alepper··on Temperature chart for the last 11,000 years
> Another is that those error bars are probably 95% confidence

The legend claims one-sigma (68% confidence assuming normality)

Page 1 of 2Next →