in crypto class today, prof. Rabin mentioned that in world war II, the government decided that they had to test all the soldiers for syphilis and a few other diseases. the problem was that blood tests were extremely expensive and they couldn’t afford to pay for blood tests for all N thousand soldiers knowing that probably less than 1% or so would actually be infected. they had to find the few soldiers who were infected but they didn’t want to spend all the money on expensive tests for soldiers who weren’t infected.
<p>the novel solution they came up with was to take groups of the blood samples, maybe 100 per group, mix them together and test the mixture. if it came back negative, they knew that all 100 of those soldiers were healthy; if it came back positive, they’d break it up into smaller and smaller groups until they’d isolated which soldier was infected. by picking the sizes of the groups intelligently, they could effectively test large numbers of soldiers quite cheaply.</p>
<p>Rabin then went on to explain an algorithm for doing mass verifications of digital signatures using a similar strategy.</p>
<p>i think the whole syphilis testing example is a wonderful example of how a good understanding of the problem and a little cleverness can really pay off. it’s probably also a good explanation/example for the layperson of what computer science is really about and why algorithms are important.</p>
<p>the actual algorithm used interests me as well. the trick to applying it would be to find a situation with something analogous to the mixing of the blood; you need a large scale boolean operation:(A or B or C or …) that will let you combine tests over large groups. then you also need the probabilities involved in the problem to be small enough that combining the tests will help you. eg, if 99% of the soldiers could be expected to be infected, the divide and conquer strategy would end up being more expensive than just testing each soldier individually.</p>
lani came up to visit and prasanth came down from maine for the weekend.
<p>we were standing outside Tom’s waiting for a table to open up so we could get breakfast and milkshakes when someone rode by on a Segway. there were some people on a golf cart with a videocamera following and filming.</p>
<p>after breakfast we went down to the <span class="caps">MOMA</span> but the line was massive so we went to the natural history museum instead and looked at various dead animals stuffed and behind glass.</p>
<p>then we watched Blade 2. it was cheesy, not terribly creative and the special effects were overdone. still, it was entertaining and there’s something about that whole cyber-vampire aesthetic that i find innately appealing even if the plot doesn’t really make sense and the acting is uninspired. </p>
<p>we spent the rest of the night at Decibel, a sake bar down on east 9th st, having sake and japanese snacks.</p>
after reading a few intriguingreviews last week, i decided to give Sorcerer Linux a try. the thought of a distribution that was completely compiled from source on my own machine and had the ability to automatically keep all the software installed completely up-to-date was more than enough to make me drool.
so last friday night, i backed up all my data and made careful notes of my hardware configuration. on saturday i went to download the ISO image for the install cd from what was the current site at the time, sorcerer.wox.org. instead of the page i’d seen before, i was redirected to the lunar penguin site. there had been mention in a few of the reviews that Kyle Sallee, the main developer of Sorcerer was getting a job and wouldn’t be able to continue working on it. from what i could glean from a quick look at the lunar penguin site, it looked like kyle had finally given up and abandoned sorcerer and lunar penguin had taken its place. i decided to hold off on installing just to let things settle down a bit.
so i installed Debian instead, spent a few days trying unsuccessfully to get networking working, gave up on debian and reinstalled mandrake. all the while i read through the Sorcerer mail archives trying to figure out what had happened and what direction things were moving in.
what i found was absolutely fascinating. it was a little more complex than just being kyle running out of time and energy to work on the project. while none deny that kyle is a fantastically talented coder who did some great work, there were apparently some personality conflicts. he would consistently reject patches that others contributed. in general it looked like he only wanted contributors who would do exactly what he told them and who would do all the grunt work for him. but he would refuse any contributions that came with input on the direction of the project. all this time, he was loudly complaining that if people didn’t start helping him (on his terms only) SGL development would have to stop.
naturally, flame-wars ensued on the mailing list, egos were damaged, tempers flared, and kyle became less and less coherent. some of the other developers, who were largely interested in having periodic “stable” releases forked the code and created the lunar penguin distro. around saturday, something in kyle snapped and he took down the sorcerer web site, replacing it with a redirect to the lunar penguin site. from this and some comments he made to other people, it appeared that he was stepping down from SGL and was endorsing LP.
meanwhile, the rest of the sorcerer developers, free from kyle’s restraints got busy picking up the pieces, reorganizing and getting things going again. they put together a new website and got back to work on the code.
but things got weirder. the original SGL website changed from redirecting to LP to an almost surreal manifesto. unsigned and written in the third person, attacking the LP team and the SGL developers alike and making vague, questionable legal threats. no one seems to have heard directly from kyle since it appeared. he hasn’t come forward to either confirm or deny that he wrote and posted the diatribe or to answer any of the many rebuttals to it.
after following this whole saga i figured that at the very least i should install sorcerer just to make sure it was worth the time and energy i was putting into researching it. the amount of activity and the speed with which the SGL developers recovered the project after kyle pretty much deliberately tried to kill it assures me that SGL isn’t going to be abandoned anytime soon. technically, i have yet to hear any criticisms of it beyond bug reports on some weird configurations.
so i downloaded and installed. i started wednesday night and, because i hadn’t RTFM’d carefully enough, i screwed some stuff up and couldn’t get it to boot without a rescue disk. it took about 5 minutes on irc yesterday to find someone who knew how to fix it to help me out. when i went home last night i made the change and everything started working flawlessly again. i got networking up without a hitch, updated the system, rebuilt it so the binaries of the minimal system that came on the install CD were replaced with freshly compiled and optimized ones. compiling is slow so that took pretty much all night. i started xfree86 compiling before i left for work this morning; i expect that it’s still going as i write this. i’ll still have to compile gnome and kde before i have a whole desktop machine again but already i’m impressed with how smoothly things have gone.
when you go to compile an app, sorcery automatically figures out all of its dependencies, downloads those and compiles them. i’m not really done yet but so far i’m definately impressed with sorcerer. with some UI work on the installer and better documentation i think sorcerer has what it takes to be a major distribution. being highly optimized, configurable and constantly updated should make it the distro that all the “cool” geeks are running within a year or two. of course, since the install takes so long and you need to know a lot about linux just to get it working, we’ll probably still be handing out redhat or mandrake CDs to newbies.
since digitally i sign every email i send, and i have to type in my GPG passphrase every time, i’ve typed that passphrase many, many times over the last couple years.
<p>nevertheless, i still have the occasional day like today when, for some reason, the connection from my brain to my hands is scrambled and for the life of me, i can’t type it in correctly. </p>
<p>it mystifies me. i’m sure i’ve gone for weeks at a time without mistyping it a single time but some days i screw it up every time i type it unless i consciously slow way down and enter it very carefully and deliberately.</p>
<p>the odd thing is that i can still type other stuff normally. it’s just that one passphrase that’s been hardcoded into my neural pathways that gets screwed up.</p>
as much as i like to slag on the big media conglomerates like aol/time/warner, i have to hand it to mtv: the osbournes is one of the funniest shows on tv. i really watch very little tv, so that’s probably not saying much coming from me.
<p>omar and allison (my roommates from the summer) came over tonight and we had 40’s and watched the Osbournes. it’s only the second show of the season but i find myself really enjoying it. honestly, i feel a little guilty that i actually like something mtv has produced. i feel dirty.</p>
<p>i think what i find most amusing is that of the entire family, ozzy is really just an innocent bystander. compared to the rest of them, he’s the sane one. </p>
<p>the only *bleep*ing problem i have with the *bleep*ing show is that *bleep*ing everyone in the *bleep*ing family *bleep*ing swears so *bleep*ing much that you *bleep*ing can’t *bleep*ing make a *bleep*ing word out. but it’s still *bleep*ing funny.</p>
hanging out at the bar tonight with obert, julintip and her friends i had an interesting little idea.
<p>suppose everyone had a tiny portable electronic device on them that stored their musical preferences and had short range wireless capabilities. then, if you had a jukebox that could detect and talk to those devices, it could tailor its playlist to roughly match the musical tastes of the people in the immediate vicinity.</p>
<p>i think it would be really nice. sort of an automated, telepathic dj. you could extend the idea to other places that play music: bars, clubs, even replace the muzak in elevators. i think it would be great if i stepped into an elevator alone and the barry manilow that was playing was quickly replaced with some good, heavy industrial or something.</p>
<p>of course, the main problem with this idea is the chicken and egg problem. if no one has the devices, it wouldn’t make sense to have the jukeboxes around and vice versa. so i’d suggest initially putting the technology into cellphones. enough people have cellphones already and always carry them with them that it would help bootstrap the system.</p>
<p>sprint (i think it’s sprint) has a service where you can hold your phone up to some music playing, dial the right number and it will tell you the artist and song that you’re listening to. if you combined this idea with a “i really like this song” and “i really don’t like this song” buttons on the phone, people could easily train it to their musical tastes. add in some data-mining like amazon uses to tell you that people who bought book X also frequently bought book Y and the system could train itself even better <em>and</em> alert you to new stuff that you might like by talking to the other devices it comes in contact with. if you’re in a room with someone who likes a lot of the same music as you, it could automatically add some of their preferences to your system.</p>
<p>you could also get CD players and various home stereo equipment that talk to your device and tell it that since you listen to a particular CD a lot, you probably like that album.</p>
<p>since i’m really into wearables and ubiquitous computing, i also think it would be need to add some contextual awareness. maybe if the device had a way to read your pulse/blood pressure/skin conductance/etc, it could tell what kind of mood you’re in and learn to associate particular groups of songs with particular moods. if you’re driving in your car, it could play good driving music for you; if you’re working on the computer, it could play whatever you like to listen to while you work; if you’re just chilling out and reading a book, it could play more mellow background sort of music.</p>
<p>probably not feasible at the moment but as cellphones and <span class="caps">PDA</span>s get smaller, more powerful, more widespread, and with more wireless capabilities, i think it could work quite nicely.</p>
<p>so if you like the idea, please desseminate it so that if in ten years, some company tries to patent the technology, there will be a lot of prior art to fight them with.</p>
<p>i’d set aside the weekend to install <a href="http://www.distrowatch.com/sorcerer.php">Sorcerer <span class="caps">GNU</span>/Linux</a> on my computer. the combination of having a highly optimized distro custom compiled for my machine and the claims of seamless upgrades had me drooling. i’d wanted to do a <a href="http://www.linuxfromscratch.org/">linux from scratch</a> install for quite a while but i know how tedious the endless “./configure; make; make install” process can get. <span class="caps">SGL</span> seems to offer all the benefits but with a more streamlined process.</p>
<p>so last night i printed out and read all the documentation, made careful notes about all my hardware and configuration stuff and backed everything up. this morning i go to download the latest iso images for the install cd and find that the sorcerer website was now redirecting to <a href="http://www.lunar-penguin.com/">lunar-penguin</a>. upon further investigation, it appears that <span class="caps">SGL</span>’s man developer has run out of time and energy and given up on the project. lunar penguin is one of several parallel projects by some of the other developers trying to reorganize and continue with the project.</p>
<p>at any rate, <span class="caps">SGL</span>/lunar-penguin is in a state of flux at the moment so i think i’ll hold off on installing. i plan on watching the mailing list and websites for the next couple weeks and trying again when it stabilizes (or at least when lunar penguin gets a better name).</p>
<p>but i got myself all worked up to spend the weekend playing with a totally new installation so i’ve got to do <em>something</em>. i’m thinking maybe i’ll check out the newest debian release and then maybe play with some of the dangerous low-latency kernel patches…</p>
lani was up for the weekend. we intended to hang out with mimi while she was back visiting new york but managed to miss her at every turn.
<p>on friday night we went down to some club called the ‘slipper room’ in soho to see Avenue D (daphne and debbie’s dirty rap group) perform. everyone there was young and annoyingly trendy. there was excitement in the air because a rumor was floating around that Daft Punk was hanging out in the club that night. but no one knows what they look like so it turned into a game of ‘spot the french guys’. they probably look just like any of the other young trendy people though so i don’t think anyone was successful.</p>
<p>Avenue D was good though. they had 6 or 7 songs this time; much more than the 1 and a half songs they had last time we saw them. while it doesn’t seem possible, they’ve gotten even raunchier. apparently they’re even starting to build a small following.</p>
<p>on saturday caron came over and we went out for mexican food (living in a latino neighborhood means that i have to deal with a near constant assault of loud salsa and spanish dance music but redeems itself with the high availability of quality burritos) and watched Ghost World.</p>