TriNetre - Archive for July 30, 2003
(no longer updated)
July 30, 2003
Relativity sinks the submarine
[Technology]
@ 05:10 PM
According to Nature, a Brazilian physicist has resolved a paradox caused by Einstein's theory of relativity. Called the"submarine paradox", the paradox goes:
According to the theory, objects traveling at close to the speed of light appear to get shorter when viewed by stationary observers. But from the viewpoint of those on the moving object, the observers - who are receding at close to the speed of light - appear shortened instead. Other dimensions remain the same.
When these notions are applied to a submarine just below the water's surface, an inconsistency seems to arise. Spectators on an anchored ship would see the submarine shrink as it moves parallel to the surface at near-light speed. The resulting density increase would sink the vessel. The submarine crew would see the opposite: water rushing past them would contract and get denser, making the submarine more buoyant and causing it to rise.
Relativity insists that both viewpoints are equally valid - so does the sub sink or swim?
When these notions are applied to a submarine just below the water's surface, an inconsistency seems to arise. Spectators on an anchored ship would see the submarine shrink as it moves parallel to the surface at near-light speed. The resulting density increase would sink the vessel. The submarine crew would see the opposite: water rushing past them would contract and get denser, making the submarine more buoyant and causing it to rise.
Relativity insists that both viewpoints are equally valid - so does the sub sink or swim?
The result of the solution - the submarine sinks.
Intelli-Aggie source released
[Software]
@ 01:11 PM
I think I have tested this enough and it seems to be working. So, here it is, the pre-alpha source code for Intelli-Aggie.
Intelli-Aggie is a proof-of-concept RSS feed aggregator and sorter that does the following:
- Fetches user defined RSS feeds.
- Categorises news items in the feeds into user defined categories based on user defined keywords.
- Generates list of these news items grouped in various views. For an example output, check this earlier post of mine.
- The most novel thing about Intelli-Aggie is that the system tries to adapt according to the reader's reading preference, trying to show him/her more interesting and relevant news items first.
- MySQL database (latest 3.x or 4.x stable release)
- Perl (*nix Perl or Windows Active Perl)
- Perl modules- DBI, Date::Calc, Config::Simple, LWP
- Apache web server or any other webserver that can server Perl based CGI files.
- User ability to create database and tables and to insert,update and delete data in these tables.
- User ability to run CGI scripts.
- Knowledge of Perl and MySQL.
- It would be good if you can run crontab (*nix) or schedule tasks (Windows).
As of now, I do not have any separate management interface for the addition of feeds and categories. So, you should either use phpMyAdmin (PHP) or Mysqlman (Perl) MySQL management systems for this, or of course you can go the command line way too.
Please note that this is still very raw system. Do not use it if you are not prepared to get your hands dirty, a bit. If you have decided to to take the plunge, do read the "readme.txt" to understand how much flexibility is inbuilt into the system and how you can tweak things around.Free Software vs. Open Source
[Philosophy]
@ 11:00 AM
Tim O'Reilly tries his hand at clarifying some differences between Free Software and Open Source philosophies.
On Laughter
[Quotes]
@ 09:45 AM
Laughter is the shortest distance between two people.
-- Victor Borge
In a related news "Happiness helps fight off colds".
-- Victor Borge
