Brain

Sunday , 3rd August 2008

Chip gives brain a link to world

A clinical trial was under way for the system that lets paralyzed or speechless people communicate and even move about in a wheelchair by means of a chip implanted on the brain's surface.

For use by people with:

• Spinal chord injury
• Paralysis due to stroke
• Muscular dystrophy
• Amyotrophic lateral sclerosis(ALS, or Lou Gehrig's disease)

1. Person thinks about an activity,such as moving a computer cursor or turning on a television.
2. Sensor chip detects faint electric impulses from nerve cells in brain.
3. Wires transmit impulses to connector on skull
4. Electronic amplifier strengthens signals
5. Cable sends signals to personal computer, which carries out orders

• Sends email or computer-generated voice messages
• Controls telephone,television,lights
• Controls medical device,drug delivery
• Moves limbs, controls bowel or bladder(with mechanical assistance)

This article was published in 2006.

Google 2

Searching and Ranking

When people search Google, they are asking the company to find every instance of the term in its index and rank the corresponding documents by their relevance.

1. The user types a search query; the typical query is two or three words, which can make finding the most relevant results challenging; roughly one in 10 queries is misspelled.


2. Before Google provides any information, it indentifies the searcher's location through his or her Internet Protocol(IP) address. The IP helps speed up the search by sending the request to the nearest data center and allows Google to indentify geographically appropriate ads.


3. The query is sent to central network, then redirected the nearest data center.
   
4. At the data center, the search term is run through the index; matching terms are sent back to the central network, then to the user with a summary of the Web page, called a "snippet"

THE "SECRET SAUCE"

Google determines which Web sites are most relevant to a search term by using its "secret sauce", formula that weighs more than 200 measurements, such as the number of times the search term appears on a Web page, the number of visitors to the page and the Page Rank- the number of sites linking to the page and the popurality of those sites.

google 1

This is very interesting information for those who want to know how google works

How Google Works
Google seraches harness one of the world's most powerful supercomputers. A search,which typically takes less than half a second, is the result of a complex journey that typically makes at least two stops, often thousands of miles apart.

1. Google creates its own version of the internet, using automated programmes called Googlebots, which crawl the web in search of new information. Web sites known to be important and frequently modified are scanned every few minutes; sites less frequently updated may be scanned every few weeks.
2. Googlebots feed key information from a web page to google's central network; URL, full text of the page,references to images and other embedded files and specific information the site owner creates about the page, called metadata.
3. At the central network, the information is indexed; every word that could be used in a search query is listed along with information referencing Web sites where the word can be found.
4. The index is broken into "shards" and sent to data centers - facillites made up to thousands of servers wired together around the world; because centers may have slightly different versions of the index, depending on when they received the last update, users in different places may get slightly different results for the same search