Sunday, April 29, 2007

Sunrise

I came along a phrase on a blog of a friend:

For example, the linguistic, traditional truth of 'the sun rises' is in contradiction with the modern, contemporary notion of heliocentrism.

Although I understand what he means by this example, I think his conclusion is not entirely true.
The rising of the sun is an observation that is done by everyone on the surface of planet Earth. This observation does not contradict heliocentrism, because heliocentrism is a possible conclusion that can follow this observation. The real contradiction is between heliocentrism and another conclusion of the observer seeing the 'sun rise', known as geocentrism, the traditional view, ie. since the Middle Ages in our Western view of the world.

Traditionaly, the observation of the sun rising led to the conclusion that the sun must revolve around planet Earth.
Planet Earth was believed to be in the centre of the Universe, with the Sun, the Moon and all planets in our solar system revolving around it. Even the stars where placed in a circular band around planet Earth.
In the sixteenth century, Copernicus stated that this model was incorrect and should be replaced by a heliocentric model, where the Sun was placed in the centre of the solar system, with planet Earth and the planets revolving around the Sun. This theory was later refined by Johannes Kepler, who based his conclusions, known as the (3) laws of Kepler, on observations made by his tutor Tycho Brahe.
Copernicus and Kepler certainly came up with novell ideas, which contradicted the contemporary view (or even doctrine) of geocentrism. However, their views are certainly not new. In ancient times, long before any big civilisation was noted in the European parts of the world, Indian and Arab scientists were already familiar with a heliocentric model.

An observer, tied to the surface of planet Earth, seeing the sun rising in the morning, travelling through the sky all day, going down in the evening and disappear at dusk, until it rises again at dawn, could come to the conclusion that the sun revolves around planet Earth, if this observer believes that planet Earth is a fixed point in the Universe. With geocentric believes, this is a logical conclusion.
The same observer, also tied to the surface of planet Earth, sees the sun rising, but believes that it is planet Earth that revolves around the sun, as propagated in the heliocentric model, can explain this too. This observer might come to the conclusion that between moments he sees the sun rise, go down and rise again, planet Earth makes a complete revolution around the sun. We know this isn't true, as planet Earth revolves around its own axis, resulting in the day-night cycle of the sun rising. Actualy, the revolution of planet Earth around the sun defines a year, where different seasons (spring, summer, autumn and winter) cycle, instead of different parts of day (morning, afternoon, evening, night) caused by the axial revolution of planet Earth.

In both models, geocentric and heliocentric, an observer tied to the surface of planet Earth can see the sun rise, but depending on the applied model, he can explain it in another way.

The contradiction lies in the models being used and not between the observation and one of the derived models.

Thursday, April 26, 2007

Friends blogging

Last week some of my friends started a blog. They all blame peer-pressure to start a blog of their own.

Funny thing is, the style of their blogs resembles very much how I know them.

Tuesday, April 17, 2007

Nearly 25% uses Firefox in Europa

According to a survey of French webmonitor XiTi, nearly 25% of all visits to websites in Europe is done with Firefox.
For Belgium, it is 18,7%, a little less than the European average. But this is still an increase of +1,4 (+8%) compared to last year's figures.

Sunday, April 01, 2007

Google's April Fool : TiSP

Today I read a story on Slashdot about Google launching a free wireless broadband service, called TiSP. A link of how it works was provided, leading to a page on Google's website.

TiSP installation kitOn this page was a picture of an installation kit and instructions on how to get your wireless network to work. Going short : You have to flush a cable through the toilet, into the sewage system and connect one end to a wireless accesspoint. The other end is picked up by a Google engineer, located somewhere in the sewage system, connecting it to a large and fast fiber optics network.

It sounds all very promissing and it is presented very professionaly, so it seems almost believable, but it is somewhat unrealistic and inpractical to flush a cable to get wireless internet access. Combine this with the date the story was released (april, 1st) :
This must be Google's April Fool's day joke. Very funny!

Friday, March 30, 2007

Am I a nerd?

I came along a funny little quiz on Bruce's blog.

Your Result: Science/Math Nerd
 

(Absolute Insane Laughter as you pour toxic chemicals into a foaming tub of death!)

Well, maybe you aren't this extreme, but you're in league with the crazy scientists/mathmeticians of today. Very few people have the talent of math and science is something takes a lot of brains as well. Thank whosever God you worship, or don't worship, so thank no deity whatsoever in your case, for you people! Most of us would have died off without your help.

Literature Nerd
 
Gamer/Computer Nerd
 
Social Nerd
 
Anime Nerd
 
Drama Nerd
 
Artistic Nerd
 
Musician
 
What Be Your Nerd Type?

Sunday, March 18, 2007

Computers need help

Computers are good at calculating, searching through data and doing other automated tasks. And they're fast doing so. They're much faster than any human doing these tasks.
That's why computers are used for assisting human beings performing certain tasks or, in some cases even replace the human being.

But don't despair. There are some tasks a computer can't do. And that's when a human being is needed to help the computer.
A computer can't easily recognise objects shown in a picture, something a human being does without any problems or hesitation. If you show a picture of 'a car by a lake on a sunny day' to a human, he or she will tell you it's a picture of a car with a lake in the background. It seems to be nice that day, because of the blue sky and the small clouds.
If you present the same picture to a computer, depending on the complexity of the algorithm being used, you well get an answer like : large blue surface with green and red area's, or maybe (if it's a very strong or specialised algorithm) red car on blue background. The algorithm probably won't be able to tell the difference between the blue of the sky and the blue of the lake.
The same is true for recognising text. A human viewer will recognise a word or some characters without difficulty, even if the characters are deformed, written through and over each other or when the colour of the letters and the background change. Computers can detect characters and words, but only if it knows the used font, if the contrast between the characters and the background is big enough (and constant) and if the characters are nicely aligned. And even then it makes mistakes. When the conditions are a bit less ideal, a computer has a very hard time recognising characters or words. Most likely it will fail to recognise anything at all.
That's the reason why so called CAPTCHA's are used to make sure a human is performing a task on a website, like registering on a forum, leaving a message on a blog or logging into a bank-account : a computer can't read the word in the image.
This way, automated algorithms that are used to flood forums with spam, are stopped (or delayed, as the algorithms to read captcha's are getting better).

But most of the time, computers (algorithms) are unable to recognise things a human does without effort. And that's were the human can help the computer. Computers are good at looking up information that's stored in a database. So if a database would be constructed linking the picture of the car with some keywords like 'car, blye sky, sunny day, lake, ...' the computer would 'know' what is on the picture. If the computer was asked to present a picture of a 'car' or even of 'car by a lake' it would filter through the database and come up with the picture of 'the car by the lake on a sunny day'.
A computer couldn't fill the database with keyword matching data, because it is unable to recognise what's on the picture, but a human could. Of course, it would be a very tedious task for a human being to look at every existing picture and tagging it with keywords. That's why a scientists came up with the idea to turn it into some sort of a game.
The concept is easy : two randomly picked people are paired and they are presented some pictures. They have to describe what's on the picture, using keywords or tags. If both people come up with the same keyword, they are granted some points and the next image is presented. The goal is to earn as much points, i.e. get as many matching keywords as possible, in a defined timeframe. The best scores are added to a highscore list.
The concept is simple, but effective. Google is using this 'game' to tag pictures found on the web, in order to return the best matching search results for images.

So, for now computers still need human assistance to perform certain tasks, like recognising characters, text, images or every day objects or understanding what a text or conversation is about. But maybe some day, computers could pass the Turing Test, and they would be able to 'recognise', 'understand' and maybe 'think' like humans do. But it seems that computing and Artificial Intelligence have a long way to go to be able to do that. Until then, computers still need help.

Monday, March 12, 2007

Old love rediscovered

This weekend I rediscovered something I haven't felt for quite some time now : I was very excited solving a mathematical problem. I was so excited, I lost track of time. It was after a few hours I realized I had been busy looking into the problem and looking up some stuff, without taking a break.
Last few years, most of the time when I'm studying or getting some work done, I get distracted after a time and I take a break or do something relaxing. Most difficult part is to stop taking a break and start studying again. And sometimes I'm taking more and longer breaks than that I spent time studying.

I haven't solved the particular problem yet, I have to look into it some more, but I'm eager to continue working on the problem and finding a solution.
I'm very glad I found this drive to solve problems again. I thought that I lost it, but now that I got it back again, I'm looking forward on digging into some more mathematical and physics problems.
I can't realy describe what it feels like to have found that drive again, but it feels very good. And I like it a lot!