Week 12 how searchenginessearch
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Search engines use algorithms and spiders to search the web and structure results for users. Spiders crawl the web by following links to find new pages to add to their databases. All search engines use search algorithms to rank results by factors like popularity, link density, and keywords. Google's algorithm is called PageRank and ranks pages higher that are more popular and linked to. Search engines regularly update their algorithms to improve results quality. While databases use controlled vocabularies, web search has no standards, so we must use keywords, fields, and related terms.
![Search Algorithms are Proprietary
Most search engines keep their search algorithms
secret, or proprietary [that means it is a corporate
property, and they keep it partially secret.
All search engines feature different [or at least
slightly different] search algorithms
All search engines use some form of their own
search algorithm](https://image.slidesharecdn.com/week12howsearchenginessearch-161104010221/85/Week-12-how-searchenginessearch-6-320.jpg)
![Google Search Algorithm
Let's look at the most well know search
engine and how it searches
Google: their search algorithm operates according
to a basic principle of relevance ranking
results are ranked according to an algorithm they call
PageRank [name is patented by Google]
See link for basic explanation of origins of Google search
*http://en.wikipedia.org/wiki/Google](https://image.slidesharecdn.com/week12howsearchenginessearch-161104010221/85/Week-12-how-searchenginessearch-7-320.jpg)
![Algorithms in Simple Terms
However, the algorithm [as most search engine
algorithms] can be broken down into basic concepts of 1)
popularity, 2 ) density, and 3) keywords:
site popularity [how many other users search the site]
site density [how many other sites link to it]
Keywords
Keywords are still key [no pun intended] and how they intersect with
the first two
These are considered in:
ranking a site
including it in your search results.](https://image.slidesharecdn.com/week12howsearchenginessearch-161104010221/85/Week-12-how-searchenginessearch-10-320.jpg)
![Updating Search Algorithms
If that weren’t enough, search
engines regularly update their
search algorithms
http://www.webmarketingpros.com/blog/h
ow-to-recover-from-the-google-penguin-
update/
http://blog.junta42.com/2011/04/4-
steps-to-make-googles-panda-update-
work-for-you/
Google released two
updates in the past few
years, termed ‘Panda’
and ‘Penguin’
[similar to updates to
PC or MAC operating
system, down to the
catchy names]](https://image.slidesharecdn.com/week12howsearchenginessearch-161104010221/85/Week-12-how-searchenginessearch-11-320.jpg)
![Updating Search Algorithms
These updates were designed to catch and eliminate from
searches ‘low quality sites’ [those with little content, ad-heavy
or replicating other pages]
http://www.business2community.com/seo/animalistic-algorithms-googles-
panda-and-penguin-shakeups-0270910
http://googleblog.blogspot.com/2011/02/finding-more-high-quality-sites-
in.html](https://image.slidesharecdn.com/week12howsearchenginessearch-161104010221/85/Week-12-how-searchenginessearch-12-320.jpg)
![Technical Stuff
This is the ‘background’ information on how search
engines search
This ‘technical stuff’ is not information we need to
activate to use a search engine
[i.e. we don’t need to explicitly construct search
algorithms or know about spiders]](https://image.slidesharecdn.com/week12howsearchenginessearch-161104010221/85/Week-12-how-searchenginessearch-13-320.jpg)
![Web and Database Searching
Refer to p. 67, textbook, for discussion of controlled
vocabulary:
All databases [this includes online catalogues and
subscription databases like Ebsco] include
controlled vocabulary](https://image.slidesharecdn.com/week12howsearchenginessearch-161104010221/85/Week-12-how-searchenginessearch-15-320.jpg)
![Controlled
Vocabulary – LC
Subject
Headings
Databases and online
catalogues [Ebsco, our
RHC catalogue for
books as well as others]
• Use controlled
• vocabulary
• Allow us to
• narrow by
• subjects](https://image.slidesharecdn.com/week12howsearchenginessearch-161104010221/85/Week-12-how-searchenginessearch-16-320.jpg)
Week 12 how searchenginessearch
- 1. H O W S E A R C H E N G I N E S S E A R C H Week 12
- 2. Spiders and Algorithms Search engines perform two technical tasks: Search and Structure search for new sites and add them to their databases structure searches for users of the search engine
- 3. Searching for New Sites Search engines search somewhat like ‘spiders’ for new sites to add They crawl the web finding pages for inclusion by following links from pages already in their database: http://www.lib.berkeley.edu/TeachingLib/Guides/Internet /SearchEngines.html http://computer.howstuffworks.com/internet/basics/searc h-engine1.htm
- 4. See picture of how it works: http://computer.howstuffworks.com/internet/basics/search-engine1.htm
- 5. Structuring Searches for Users All search engines use a search algorithm to structure searches for users. In computer science, a search algorithm is an algorithm for “finding an item with specified properties among a collection of items”. *http://en.wikipedia.org/wiki/Search_algorithm
- 6. Search Algorithms are Proprietary Most search engines keep their search algorithms secret, or proprietary [that means it is a corporate property, and they keep it partially secret. All search engines feature different [or at least slightly different] search algorithms All search engines use some form of their own search algorithm
- 7. Google Search Algorithm Let's look at the most well know search engine and how it searches Google: their search algorithm operates according to a basic principle of relevance ranking results are ranked according to an algorithm they call PageRank [name is patented by Google] See link for basic explanation of origins of Google search *http://en.wikipedia.org/wiki/Google
- 8. A picture of Google’s Search Algorithm:
- 9. Google’s Search Algorithm See link for explanation: From http://en.wikipedia.org/wiki/PageRank Pretty Mathematical! We won’t go into all that.
- 10. Algorithms in Simple Terms However, the algorithm [as most search engine algorithms] can be broken down into basic concepts of 1) popularity, 2 ) density, and 3) keywords: site popularity [how many other users search the site] site density [how many other sites link to it] Keywords Keywords are still key [no pun intended] and how they intersect with the first two These are considered in: ranking a site including it in your search results.
- 11. Updating Search Algorithms If that weren’t enough, search engines regularly update their search algorithms http://www.webmarketingpros.com/blog/h ow-to-recover-from-the-google-penguin- update/ http://blog.junta42.com/2011/04/4- steps-to-make-googles-panda-update- work-for-you/ Google released two updates in the past few years, termed ‘Panda’ and ‘Penguin’ [similar to updates to PC or MAC operating system, down to the catchy names]
- 12. Updating Search Algorithms These updates were designed to catch and eliminate from searches ‘low quality sites’ [those with little content, ad-heavy or replicating other pages] http://www.business2community.com/seo/animalistic-algorithms-googles- panda-and-penguin-shakeups-0270910 http://googleblog.blogspot.com/2011/02/finding-more-high-quality-sites- in.html
- 13. Technical Stuff This is the ‘background’ information on how search engines search This ‘technical stuff’ is not information we need to activate to use a search engine [i.e. we don’t need to explicitly construct search algorithms or know about spiders]
- 14. However, it can help us in thinking of how to approach constructing searches
- 15. Web and Database Searching Refer to p. 67, textbook, for discussion of controlled vocabulary: All databases [this includes online catalogues and subscription databases like Ebsco] include controlled vocabulary
- 16. Controlled Vocabulary – LC Subject Headings Databases and online catalogues [Ebsco, our RHC catalogue for books as well as others] • Use controlled • vocabulary • Allow us to • narrow by • subjects
- 17. Web and Database Searching The Internet features no controlled vocabulary – i.e. no subject headings or agreed- upon subjects in databases We can, however: • Search specific • fields • Eliminate or • specify terms or • related terms