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Comment: Re:Are you new? (Score 1) 171

by Natural Join (#41604055) Attached to: Can Google Base Ads On E-mails Sent To Gmail Accounts?

As to the topic at hand, I find it interesting that the question isn't "Should google be targeting non-subscriber email ads", but whether or not they should be looking at ANY email content.

Email fundamentally requires computers to read your email. Your email client sends an RFC 2821 formatted message to an SMTP server, and that server reads your email content. If it didn't read the To: header, it wouldn't be able to send the message to the right destination. If it didn't read the body, it couldn't pipe the body out to file storage or out another SMTP/IMAP/whatever connection to the recipient. Being concerned about computers reading your email is like being concerned that your mailman is driving your paper mail around in a truck. It's fundamental to the process.

If you say, sure a computer can read it for one reason but not for another, then you're saying you think you ought to have the right to control what software consenting adults write for each other. I'm against you having that power over me.

Comment: Re:Wait for rap and hip-hop to fall out of favor (Score 2) 474

by Natural Join (#41500987) Attached to: Ask Slashdot: Hacking Urban Noise?

Lower sound frequencies penetrate more easily than higher frequencies.

I've done some studio tests. We built a sound chamber with two foot think CMU walls and ceiling. We embedded speakers with broad frequency response. We pumped 108 dB of pink noise out the speakers, and measured sound outside the chamber. You could just barely tell the sound was on. At higher frequencies, we saw 80 dB of reduction. At 16 Hz, there was *no reduction whatsoever.*

The good news is that 16 Hz is below what you can hear. But the basic principle is that the lower the frequency, the more sound energy will penetrate a barrier.

Comment: Re:There's a shock... (Score 1) 1025

by Natural Join (#41114133) Attached to: Study Finds Unvaccinated Students Putting Other Students At Risk

My son was born in 1999; my first daughter in 2000. My son got the MMR with thimerisol in it. My daughter got the MMR without thimerisol. My son gets straight As is school. My daughter has severe autism; at age 11 she's about as functional as a 3 year old.

This is just an anecdote; two data points aren't enough to say much. The important fact is that huge studies on thimerisol and the MMR have shown that thimerisol doesn't affect autism rates.

Comment: Re:Reducing CO2 (Score 3, Insightful) 545

by Natural Join (#40149323) Attached to: Scientific Literacy vs. Concern Over Climate Change

The only way it makes sense to make a major societal commitment like cutting CO2 emissions is through a cost-benefit analysis. In the interest of disclosure I am one of the tree-huggers who thinks CO2 emissions are a clear and urgent problem. I think you and I can none the less agree that a cost-benefit analysis is the rational way to make a decision on whether to shut down power plants (and switch to windmills or nuclear plants) or not.

The first sentence above is the best comment I've read. It is essentially the only fully rational viewpoint I've seen, because all the other viewpoints have been variations on assuming their conclusion. ("...our atmosphere is supposed to be ...") In the interest of disclosure I am one of the conservative skeptics who believes that AGW hysteria derives from the the same psychological dynamics as past hysterias about avian flu or swine flu or the world ending in the year 1000. This is not the same as saying that CO2 levels or temperature levels aren't rising.

Any effort to get us out of the political dilemma of this issue that doesn't involve cost/benefit analysis is just more politics.

Comment: Re:Pretty print it first (Score 2) 204

by Natural Join (#35423800) Attached to: Unmasking Anonymous Email Senders

This is called "stylometry": the algorithmic analysis of authorship based on the content of the work in question. There are many scholarly articles out there describing various algorithms out there you can find and read. Early efforts in this area involved testing the Shakespeare/Bacon hypothesis, who wrote which of the Federalist papers, and establishing the authorship of the 15th Oz novel.

The basic concept is pretty easy. I played a fair bit with the idea back a few years ago when I wanted to prove to myself that a certain usenet troll was actually the same person as another poster. I downloaded a bunch of 19th century novels from Project Gutenberg and tried various published algos until I could accurately cluster authorship. Telling husband and wife apart (Mary Shelley and Percy Shelley) was crazy-easy; the appallingly hard case was Charlotte and Emily Bronte. (They were sisters and grew up together, clearly having a lot of influence on each other's writing styles.)

Yes, one of the most basic issues of analysis of a stylometry algo is how well does it still work if the author is *trying* to obfuscate his style, or *trying* to imitate another author. There are algorithms that a quite insensitive to such efforts. However, they all seem to require a *lot* of text to work well. My best efforts (using other people's published algorithms) worked quite well on full novels but did not work so well given even as much as a few chapters.

Oh, and that trolled turned out NOT to be the guy I thought it was.

Comment: Re:Call me skeptical (Score 5, Interesting) 222

by Natural Join (#34275540) Attached to: Horizontal Scaling of SQL Databases?

The small startups are using NoSQL because there is, more and more, a push in the web app market to store data which does not fit into any schema.

There is no such thing as "data which does not fit into any schema", just like there is no such thing as data which cannot be encoded into binary. All data necessarily has a schema. However much or little of the schema you may choose to model in your (SQL or other type of) schema is, like the rest of software engineering, a design tradeoff.

The various NoSQL approaches do not solve the full generality of data management problems the way SQL databases do. They are narrower in scope, and as is generally the case, they can achieve better performance by virtue of doing less. They can be much faster with certain data access paths, but at a cost of the fact that other data access paths become prohibitive.

The frustrating thing for many of us is that the NoSQL spin on data management is about where mainstream data management was in the 1960s. As the field matured, it learned many important lessons, all of which are now being tossed out the window by people saying "oh we don't need that" but of course, they just haven't needed it yet. As these problems become apparent to them, they will spend the next decades of their lives reinventing what the data management field figured out in the 80s and 90s. Until then, they'll be making beginner mistakes, like thinking that their data somehow doesn't fit into any schema.

Comment: Re:If you want accuracy... (Score 1) 359

Exact computable real arithmetic? So what is pi+e? An exact irrational number requires infinitely many integers to represent it.

And yet you were able to represent this value with only 4 characters.

Read up on continued fractions and computer algebra systems and get back to us. There are more ways to do things than just those in the C library.

Comment: Re:Not fair to run down the black/grey hat hackers (Score 1) 149

by Natural Join (#31928288) Attached to: 25th Anniversary of <em>Hackers</em>

I think his point is that they weren't scamming people for millions of dollars, it's more like they were commiting petty theft. Yeah, it's wrong, and probably illegal (although there may not have been many laws about this stuff back then). But it's not 'nazi-wrong'.

I completely agree. Why anyone thinks I might not is beyond me.

Comment: Re:Not fair to run down the black/grey hat hackers (Score 1) 149

by Natural Join (#31928172) Attached to: 25th Anniversary of <em>Hackers</em>

Clearly you're one of the "new generation of hackers" (read: Hopped on teh intarwebs bandwagon in 1999 and now consider yourself an authority on geek culture).

Not exactly. I hoped on the timeshare BASIC bandwagon in 1972. My idea of geek culture is mostly outdated. To me, a "newb" is someone unfamiliar with the conventions of usenet, rather than someone you don't like on an online FPS. I guess the youngsters spell it "noob" now.

Comment: Re:Not fair to run down the black/grey hat hackers (Score -1, Troll) 149

by Natural Join (#31914124) Attached to: 25th Anniversary of <em>Hackers</em>

"most of the hackers ... weren't doing it to "steal and destroy" ... phreakers stealing phone service were often only motivated by the desire to be able to dial long distance BBS's ... they too were motivated by ... the thrill of accomplishment (over defeating a security system, finding a way to make a system behave in a way it wasn't intended, etc.).

Stealing phone service, for whatever reason, is stealing. Defeating someone else's security system, or making someone else's systems behave in a way they don't want them to is a kind of destruction. Those sorts of people belong in jail.

Comment: Re:Interesting Article But... (Score 2, Interesting) 176

by Natural Join (#31219060) Attached to: Stone Tools Found On Crete Push Back Humans' Maritime History

Despite this, they never really say why this changes their view on sea-faring of ancient times. Currently the north shore of Africa is about 200 miles from crete, but what they seem to have failed to take into account (or at least mention in the article) is that in ancient times sea levels were much much lower. This is estimated to be due to deglacification around 7k years ago. The National Institute of Oceanography states that in studies the sea level of India's coast were about 100m lower about 14k years ago, so extrapolating (a dangerous game I know =) we could say it may be possible that at some point the voyage to Crete was either walkable, or a very short sea voyage.

Not if the sea floor was anything like it is today. A drop of 100m/328 ft would get you about 7 miles further off the coast of Africa than with today's sea levels. On the Crete side, the sea floor drops precipitously off the southern coast, and 100m gets you only about 1 mile. So the lower sea level you cite would shave less than 10 miles off the 200 mile journey.

You can verify the sea floor elevation with Google Earth.

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