April 2006 Archives

News to me: you can use The Internet from planes now; I knew that this was in the works, but I didn't think it had actually been implemented yet. Apparently Lufthansa (others?) has WiFi planes that communicate with the outside world via satellite links. As is thoroughly explained in this post, the plane connects to a geostationary satellite and has it's own /24 network. The planes intelligently decide which satellite to use based upon which will produce shorter routing at the ground station and are able to dynamically change this throughout the flight. As the Renesys blogger shows, the planes announce their route changes thus allowing graceful switches amongst the satellites. Cool.

This presentation explains the system that Boeing developed.

Ever drive behind an ambulance and notice the chains hanging from the rear axel? I've always wondered what those were for and today listening to CarTalk they suggested to a guy who was complaining about being shocked by his car to use a ground strap or chains that would drag on the ground to...ground the car. For ambulances, I would bet that being at ground potential is importand for their instruments (EKG?) or perhaps they just don't want to shock people. Interesting.

I drove a friends auto once and a cop pulled me over and gave me a ticket for improper equipment when he saw it was an auto. -Aldo

If I was going to start wearing skirts, I'd definitely get an auto. -Ron17

Bimmerforums

I've been using del.icio.us for some time now and I absolutely love it. Not only can I access my bookmarks from any machine, it's easy for me to point people to collections of information that I've made and the organization is far superior to any other mothodology. The public-ness of it brings up an interesting vulnerability, that of spying using del.icio.us. Say that you know I write code for some software company and you have been hired to do industrial espionage for a competing firm; you can probably get a good idea of what I'm working on by the links that I grab. Just a thought.

One of the most oft encountered logical fallacies, particularly when quoting the outcome of studies or statistics, is that of confusing correlation of variables with causation; cum hoc ergo propter hoc (latin, with this, therefore, because of this). This fallacy is the root of irrational beliefs, fears and biases in otherwise intelligent and informed people.

This came to light earlier this week in a forum where some people who would generally not be considered bigoted where having a "truthful" discussion about whay they thought of black people. Statistics, such as the rate of black men being incarcerated vs. that for white men, were quoted and the crowd all pointed saying, "See, they're more likely to go to jail; the stastics don't lie, they're just bad people." This was from a bunch of people who don't want to be racist, but they found it troubling to agree with the statistics, which are true, agree with their own experiences (bad neighborhoods == black neighborhoods) and yet not see blacks as being inherently predisposed to crime.

The root of their misunderstanding lies in the logical fallacy of assuming that correlation proves causation. The most important thing to realize when reading studies or statistics is that the correlation of two variables does not mean that they are anything but related. I recently read of a study done by the US Army which found that the best predictor of whether or not someone would ever be involved in a motorcycle accident was the number of tattoos they had. Does that mean that tatoos cause motorcycle accidents or cause poeple to be stupid? No. All it means is that people with lots of tattoos tend to have motorcycles and ride them more than those without. Perhaps the root cause is that they're more inclined to take risk, but quite obviously, tattoos don't cause motorcycle riders to crash.

To get a better understanding of how to interpret studies, I highly recommend reading Freakonomics by Steven Levitt. His book examines a number of different situations and a huge amount of data using techniques like regression analysis to find the root causes in otherwise random data. For the race problem, it basically boils down to the fact that criminal tendencies are not well correlated with race but rather with low education and low income. Drawing on that, it's quite easy to understand how blacks are still associated with being criminals and easy to see just how long it is going to take for the remanants of a racist society to be removed from our civilization.

I've been reading Big Bang: The Origin of the Universe by Simon Singh, an excellent history of all cosmology. The book starts with the very beginning of astronomical exploration, such as Eratosthenes who was the first to estimate the Earth's diameter. I'm nearing the end of the book (the mid 1900's, shortly after the Big Bang theory was created) and ran across this, George Gamow's version of the bible's Genesis:

In the beginning God created Radiation and Ylem. And the Ylem was without shape or number, and the nucleons were rushing madly upon the face of the deep.

And God said: "Let there be mass two." And there was mass two. And God saw deuterium, and it was good.

And God said: "Let there be mass three." And there was mass three. And God saw tritium, and it was good.

And God continued to call numbers until He came to the transuranium elements. But when He looked back on his work, He saw that it was not good. In the excitement of counting, He had missed calling for mass five, and so, naturally, no heavier elements could have been formed.

God was very disappointed by that slip and wanted to contract the universe again and start everything from the beginning. But that would be much too simple. Instead, being Almighty, God decided to make heavy elements in the most impossible way.

And so God said: "Let there be Hoyle." And there was Hoyle. And God saw Hoyle and told him to make heavy elements in any way he pleased.

And so Hoyle decided to make heavy elements in stars, and to spread them around by means of supernova explosions. But in doing so, Hoyle had to follow the blueprint of abundances which God prepared earlier when He had planned to make the elements from Ylem.

Thus, with the help of God, Hoyle made all heavy elements in stars, but it was so complicated that neither Hoyle, nor God, nor anybody else can now figure out exactly how it was done.

So, what causes weather radar to do this?

This is just part of a script that I wrote to...do something. The pertinent part here is using WWW::Mechanize to login to a vBulletin web forum. I figure Googlebot will guide someone trying to figure out how to use WWW::Mechanize this way.

use WWW::Mechanize;
my $username = "foo";
my $password = "bar";
my $forum = "http://www.foo.com/forum/";

my $mech = WWW::Mechanize->new  (
                                    autocheck   =>  1,
                                    agent       =>  'Perl WWW::Mechanize',
                                );

$mech->get( $forum );
$mech->submit_form(
                        form_number =>  1,
                        fields      =>  {
                                            vb_login_username => $username,
                                            vb_login_password => $password
                                        }
                    );
$mech->follow_link(
    text => "Click here if your browser does not automatically redirect you."
    );