RFID definition.
Radio Frequency Identification (RFID) is tags that can be attached in humans, animals or objects. It uses radio frequency waves in order to communicate with a reader for the purpose of uniquely identifying the object or transmitting data and/ or storing information about the object.

How RFID works?

1. RFID consists of a tiny silicon computer chip and an antenna that a remote reader can scan and send to a database.
2.  Each chips gives a unique serial number to every products.
3. RFID’s antenna helps remote scanners to read the RFID tags even through materials  like fabric and plastic.
4. RFID is used by Wal Mart which requires all suppliers to use to RFID to track all Wal Mart’s products.

Several elements to grade a complete RFID system :

1. Select tags and readers – It important to select as different products requires different kinds of tags or different kind of situation require differnt kind of tecnology.
2. Execute rules –  Need to have ways for rules to be executed.
3. System intergration – Now that you have auto identification technology, you need to decide how your operations going to change.
4. Dealing with change – Need to come out with plan for handling change and system to support RFID.

The video below is considered as an up to date video as it has was added to YouTube on 28th January 2008.
http://www.youtube.com/watch?v=fg0uQ2FAg-k