Ideas are simple but powerful !

Ideas are simple but they are powerful. Here is a story of a such idea, the idea of using "Captcha". If you don't know what a Captcha is, don't be worried. I'll explain it later in this article.
I'd heard this story from a radio about "WHAT IT DOES" but didn't know "HOW IT DOES". Today I read the HOW part and thus want to share to everyone.

What is a CAPTCHA ?
A CAPTCHA is a program that can tell whether its user is a human or a computer. You've probably seen them — colorful images with distorted text at the bottom of Web registration forms. CAPTCHAs are used by many websites to prevent abuse from "bots," or automated programs usually written to generate spam. No computer program can read distorted text as well as humans can, so bots cannot navigate sites protected by CAPTCHAs.

What is RECAPTA ?
It is a free CAPTCHA service used to digitize books, news paper etc.

How does RECAPTA help in digitizating documents ?
OCR is a device used to digitize a document. The problem is that the device cannot digitize all the words in the document correctly. It informs if it cannot digitize the words. A word which is not digitized by OCR is mixed with a known word and a new captcha is formed. The new captcha is challenged to human. Those who type the known word correctly are believed to type the word to be digitized correctly. To make it perfect, the new captcha is challenged against many people. By this way the confidence of the word to be digitized is improved.

Therefore, the idea is simple but powerful !

Reference:
Recapta

Writing LaTeX equations online

Recently I needed to write a lot of math equations for a homework of Inference Theory course. I could have used MSWord or OpenOffice to write the equations. However, I know LaTeX as well. The problem is that I don't want to install it. I found following website which can be used to edit equations using LaTeX command.

LaTeX Online Equation Editor:  codecogs.com
Equation Help: Wikipedia

Below is a sample equation I've written using this website.

Khan Academy: Random Variables and Probability Distribution

 People are so nice. They share their knowledge for free. Salman Khan is one such example which runs a organization called the Khan Academy. The Khan Academy is a not-for-profit educational organization created by Salman Khan. With the stated mission "of providing a high quality education to anyone, anywhere", the Academy supplies a free online collection of over 2,000 videos on mathematics, history, finance, physics, chemistry, astronomy, and economics (Source Wikipedia).

I knew this website after I watched the video on Random Variables and Probability Distribution which I'm learning now. Lectures are pretty good. I  love such people and such activities !

Demography of Facebook

Facebook demographics of 2011 has been revealed. The figures are interesting to look at :

Generate XSD from XML

Sometimes we need to generate XML-Schema (e.g. XSD) from a given XML document. There are many tools but the one I use is called trang. Here are simple steps to generate xsd of a xml file (input.xml):

1. Download and Unzip trang-20030619.zip
2. Go to trang-20030619 folder and use following command:
java -jar trang.jar -I xml -O xsd input.xml output.xsd

Searching Assertion using TextRunner

TextRunner searches hundreds of millions of assertions extracted from 500 million high-quality Web pages.
Links:
  1. Paper
  2. Demo

Creating a RSS Feed using ROME

Creating a RSS Feed using Java is straightforward. You just need to know how to use ROME API. The website presents some sample codes too. Following code, copied from Codeidol.com, will be useful.