Or, a stupidly designed cryptographic cipher combined with an error-correcting code where again carefully corrupted packets, and requests for retransmissions, reveal information about the secret payload.
Monday, October 27, 2008
Turbo code interleaver attack
I wonder if the deterministic nature of most turbo code interleavers may form the basis of an attack, for example, a Denial-of-service attack where carefully corrupted packets induce worst-case computational load (maximum number of iterations to achieve convergence) thereby causing your 3G cell phone to quickly run out of battery.
Monday, October 20, 2008
Chess armageddon
A match of an unlimited number of games, but with a time limit for the total time of all moves of the match for each player. For example, if a game ends with players having 2 minutes and 1 minute remaining on their clocks, the next game begins with the clocks set to that time remaining.
A match ends if one player leads by (say) two points, or if one player loses on time. There is guaranteed to eventually be a result.
This method seems superior to the current "white must win" Armageddon tiebreak method because it avoids the white-black asymmetry.
Another idea (by someone else) is to have geometrically decreasing amounts of time for successive games. This is elegant because the geometric series converges, so the match is guaranteed to take finite time.
Thursday, October 16, 2008
Image search
Quite obviously, the next big thing will be image and video search; in particular, given a sample image of a person, search the internet images or videos of that person, as well as the textual information about that person. The technology already exists for scanning the Super Bowl crowd for terrorists, but is not deployed yet for normal people to use.
It's a nice hard AI problem, because one can not only do straight face recognition, but also use textual context to figure out names of people, locations and events, and follow the thread of those names, to find more images.
And the world will become a creepier place.
Tuesday, October 14, 2008
Porn market
(or, "Capitalizing on your ASSets" ;-)
How much would you need to be paid in order to post naked pictures of yourself on the internet? How much would you be willing to pay to see naked pictures of someone on the internet? There is market opportunity there for a trusted third party broker.
A model posts censored photographs of him or herself and establishes a threshold amount of money at which the uncensored photos will be released. The uncensored photos are deposited with the broker, which also collects money from "donors" interested in viewing the photos, holding the funds until the threshold is reached, at which point the model is paid, and the uncensored photos are publicly posted.
The business model of the broker is to invest the "float" between when the money is collected from the donors to when it is finally released, to the model.
Photographic challenges can be used to establish that the model is in fact the person submitting the photographs.
Donors may withdraw if the model raises the threshold. The model may lower the threshold to immediately "cash in" on the donated funds thus far.
Monday, October 13, 2008
Donut-shaped raindrops
Are there donut-shaped raindrops? What shape can falling drops of liquid take?
Sunday, October 12, 2008
Saturday, October 11, 2008
2.7 Kelvin
Is the cosmic microwave background radiation warming the universe enough to keep certain phase transitions from happening? For example, is it why Pioneer isn't being constantly pelted by snowballs of solid hydrogen or helium, because 2.7 Kelvin is too warm for hydrogen or helium to freeze? Or why galaxies aren't all frozen into place in an infinite block of solid or liquid space?
Thursday, October 09, 2008
Turning off login drum sounds
Turning off the Ubuntu "drum" sounds at the login screen.
System | Administration | Login Window | Accessibility
or /usr/sbin/gdmsetup
or edit /etc/gdm/gdm.conf-custom to include
SoundOnLogin=false
in the [greeter] section
Wednesday, October 08, 2008
Black hole moon
A cosmic ray hits the dense surface of the atmosphere-less moon to form a mini black hole, which grows to gobble up the whole moon, a scenario that crackpot LHC opponents should examine.
If the moon were replaced by a black hole of identical mass (plus the mass-energy of the one cosmic ray that triggered the transition :-) what would it look like from earth? I predict a series of concentric rings as sunlight loops a quantized number of times around the moon, then finally "reflecting" back to earth. What colors would the rings be? How bright and how big? How does the angular momentum of the moon (one revolution per month), now compressed into a black hole, affect things? Will tides on earth be affected?
What will the tranformation from moon to black hole be like? I assume it will be asymmetric, starting from the point of impact of the cosmic ray on the surface of the moon. What kind of gravitational radiation, and will we be able to see or feel it on earth? What kind of radiation, and how much, from the heat of the collapse? How long will it take?
What do "solar eclipses" look like?
Naked Singularity?
Model the worst case scenario of a large number of electrons, all spin aligned, colliding at a single point to form a black hole.
On further consideration, this probably won't work. Electrostatic repulsion is stronger than gravity. Is there a maximum charge a black hole can have? What happens if you keep dumping electrons into an existing black hole? (Practically, of course, it gets harder and harder as the black hole gets charged, and you face the problem of keeping the positively charged plasma left over away from the black hole. Maybe shoot the plasma away at high speeds to become a cosmic ray.)
Angular momentum per unit mass
What is the angular momentum per unit mass for various objects, from electrons to millisecond pulsars?
Moon overhead
Assuming spherical bodies, how large is the patch on earth where the moon is directly overhead? The patch on the moon vice versa? The sun? Other planets?
Insolation Force
How much force does the earth (and other celestial bodies) feel from the momentum of the solar radiation it intercepts?
I love Paris in the the spring time.
Give me a paragraph layout engine that automatically replicates the last word in a line to the first word in the next line, for ease of eye flow on wide text.
Graph programming language
Most programming languages, not C, have decent syntactic ways of naturally manully specifying lists, trees, and two-dimensional arrays. But not so arbitrary graphs. We need a node place and edge draw syntactic primitives, and nodes encircle for non disjoint grouping. Maybe in 3D.
Tuesday, October 07, 2008
Disk contention
How do you "nice" a process using disk, possibly swap? Need preemptible seeks and intelligence for multiple disks.
Sunday, October 05, 2008
open-vm-tools on ubuntu hardy
This link: How to Install VMware Tools on Ubuntu Hardy 8.04 under VMware Fusion is a good start, but is out of date. Latest version is open-vm-tools-2008.09.03-114782.tar.gz . To compile it we need a newer version of uriparser than Ubuntu supplies. I downloaded uriparser-0.7.2 from sourceforge and installed it locally (NOT in /usr/bin!). Unfortunately, the configure script of open-vm-tools is screwed up such that making it see the locally installed uriparser using CUSTOM_URIPARSER_CPPFLAGS and CUSTOM_URIPARSER_LIBS did not work. When looking for the lib, it needed the -I which was not passed. Got some errors about uriFreeQueryListA. However, setting the environmental variables CFLAGS CPPFLAGS and LDFLAGS with the -I and -L paths did work.
Also, the command line you need for git is git clone git://git.opensource.vmware.com/opensource/open-vm-tools
Friday, October 03, 2008
md5 checksums of digits of pi
The digits following the decimal point, not including the "3.", with no end-of-line newline or linefeed.
| Digits | md5sum |
|---|---|
| 1 | c4ca4238a0b923820dcc509a6f75849b |
| 2 | aab3238922bcc25a6f606eb525ffdc56 |
| 5 | c92b32fbc94e2dff3e5516401d9bb463 |
| 10 | 0c70798ef9bd5bb878f53df3f85774de |
| 20 | 089b653970518aad3828d6e8630a1ae2 |
| 50 | d2ac6f2399ea4e94ec2cdfdb99c95ad9 |
| 100 | 954a383ec609b9126d4ba2ddf0bd1b37 |
| 200 | 59433bdec0a3a97f6d2785f855506ab7 |
| 500 | 5140171f33e9c149c97c8f3643f93f3e |
| 1000 | 5398eb229b2f9b4cdc42681c110707bb |
| 2000 | bb1fd8b5786fb4b3c91467e302631533 |
| 5000 | e1de0b54b87e3dcc846be7489edbdb8f |
| 10000 | 88d4eda38e94791ab2548d8463144a09 |
| 20000 | b660e34c926544e0ac174df38829ebd6 |
| 50000 | b2a057082a245a0a41817f614d95921e |
| 100000 | de18e0d8fef70b8f925cb2392c53f145 |
| 200000 | f22b756816f38eddf86ce210b3210841 |
| 500000 | 59de28f2ce1b2e4a95576e977da64c3e |
| 1000000 | e668904c195521a2a2dfef948ac54c8e |
| 2000000 | 12887cce18c4e1bffd9505c926230a90 |
| 5000000 | eb2774b75ab2f64f7d65b2d9436491d6 |
| 10000000 | 7f5f4ad06f084278f283a661ffafb379 |
| 20000000 | 13e07d09e200aa0837bf9b6c600b1818 |
| 50000000 | 8c50bb4458cbcc2c896ea50bd32da627 |
| 100000000 | dfc9f9b7080939885afb5f7bd2e04c4a |
| 200000000 | 496423ea6297b6455f7d076e2e4e2b56 |
| 500000000 | a3e9ad8d21dff2ccdc6bc96f369e3176 |
| 1000000000 | bff5d599c5aa342ab76086392cb73695 |
| 2000000000 | b2dae9b1569c3818b2ef78a0b6ad9502 |
| 5000000000 | 1d49002df7b62bc64241452d3bf75188 |
| 10000000000 | a3f0710c37a9e709edbd2de7a8925561 |
| 20000000000 | 240039d1a31f3caf6ec6cc3750b867c8 |
| 50000000000 | 67cb35130aac39f5cb8c79235b23a204 |
| 100000000000 | be5905dc2b9073a9f4c3635a1277b14a |
These checksums are in agreement with http://www.geocities.com/tsrmath/pi/picalcs.htm.
The last three entries, 20G, 50G, and 100G, were calculated from the value of pi from JA0HXV's site and not independently verified. The values less than that were verified using Ramanujan's method in Gourdon's PiFast program.
Some variations of a million digits of pi. Let DIGITS="14159...0577945815" (999,999 digits of pi after the decimal point).
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