defined as follows: We assume page A has pages T1...Tn which point to it (i.e.,
are citations). The parameter d is a damping factor which can be set between 0
and 1. We usually set d to 0.85. There are more details about d in the next section.
Also C(A) is defined as the number of links going out of page A. The PageRank
of a page A is given as follows:
= (1-d) + d (PR(T1)/C(T1) + ... + PR(Tn)/C(TN))
- Sergey Brin, Lawrence Page;
of a Large-Scale Hypertextual Web Search Engine; 1998.
one of the smartest search engines. Google was originally created by Stanford
Brin and Larry Page, and retains a well thought out structure and methodology.
The site actually runs on thousands of linked PC's distributed in centres located
in different places around
relevant results with very fast response times.
Google uses a page ranking system
sites are returned at the top in response
to a search query. In Google's words:
In essence, Google interprets a link from page A to page B as a vote,
by page A, for page B. But, Google looks at more than the sheer volume of votes,
or links a page receives; it also analyzes the page that casts the vote.
This method ensures that the pages most highly recommended by other pages are
returned closest to the top of a search listing. This technique is really a kind
of centralized analysis of peer-to-peer data, and works quite well.
For the alternatively inclined, a detailed description of how Google uses flocks of pigeons collected into dense, low-cost clusters to rank web pages can be found here.
The Google advanced
search page provides a menu driven way to search the Internet,
and text equivalents
of these features are listed below:
"space" and "mars" but not "venus"
space OR mars
Note the OR must be capitalized.
space and (mars OR venus)
and either "mars" or "venus"
Always put brackets around OR clauses connected
to an AND.
phrase "fastest car"
and "rose" in the URL
| ||gardens filetype:pdf||Searches only PDF format files.|
that link to "livinginternet.com"|
that are related to "livinginternet.com"|
the site domain name
Other Google search options are described below.
You can set your page display preferences to a wide range of languages,
and search in
international language sets
- SafeSearch. Provides a
safe search option where most adult content pages are filtered out and
in search results
- Wildcards. Google doesn't support
wildcards, so for example instead of searching for "comed*" you need to search for
Resources. Additional Google related resources are listed below:
in Googling - A good animated guide to advanced Google search