An overview of some of the workings of the google search engine

1. Assignment :
Features of the Google Search Engine
Subject:
CS-100 ICT
Prepared By:
Waleed Liaqat
CE-2011/ Sec- C/116955
Submitted to:
Lec. Bilal
Date Submitted:
03-10-2011

2. What is the Google search engine?
Let’s start by defining what a search engine is. A search engine is a program that
searches and fetches documents that contain certain keywords or the search
criteria which you communicate to the engine through its interface.
The Google search engine is a creation of the multinational corporation Google.
Google search engine started out as a research project. Today, however, it has
become the most widely used search engine on the planet. This is due to its
simple design and ease of use, but more importantly it is because of the search
engine’s capabilities and unique algorithm that gives efficient results, that it is the
choice of billions across the planet.
How it works?
Once you specify the search criteria or keywords, this information is sent to the
Google web server which uses it to search its index of webpages and collects
webpages that match the given criteria. These webpages or websites are then
arranged in order of their relevance by a program called PageRank. This is the
very programme that gives Google an edge over other search engines. The results
once sorted are displayed with the relevancy information as well as information
such as total results and time taken to search and display.
Google’s index server contains billions of webpages. The index is updated
regularly through programs called crawlers.
Although Google search engine provides fast results, the results may contain the
search criteria but the webpage in its entirety may not be relevant to us. In such a
case, to narrow down our searches we use certain symbols such as the hyphen,
each of which serve a certain purpose.

3. We can further understand some of the features of Google search engine and
how it works through examples on the next few pages.
Problem 1: Searching for a webpage that contains one or the other element of
the search criteria.
Solution : Use of the pipe symbol (|)
Queries : Peter Pan [fig. 1(a)], Peter|Pan [fig. 1(b)]
Fig . 1(a) Entering ‘Peter Pan’ gives
the following results. The listed
webpages contain both search
terms.

4. What’s happening:
When we use ‘ peter pan’ as our search terms, webpages displayed as search
results contain both the search terms, however when we use the pipe symbol (|)
to separate ‘peter’ and ‘pan’ and search, the results are different and it is evident
that the pipe symbol works as an ‘OR’ operator. Use of this operator allows us to
expand our search results pool.
Fig. 1 (b) shows the result when
we include the pipe symbol
between peter and pan.

5. Problem 2: Searching with terms which can have different interpretations in
different scenarios e.g. ‘virus’ has a different meaning when we relate it to
computers but a whole other meaning when we relate it to medical science.
Another example is that of searching for Sagittarius which is the name of a
constellation and a horoscope which are completely different concepts.
Solution: Use of Hyphen symbol (-)
Queries: Sagittarius [fig. 2(a)], -Constellation Sagittarius [fig. 2(b)].
Fig. 2(a) Search results for Sagittarius.

6. What’s happening:
When we search for ‘Sagittarius’, the results returned contain webpages where it
is present in relation to constellation or horoscope or both. To narrow our search
results or to look for webpages where it is only explained as one of the twelve
horoscopes we use the hyphen symbol (-) before constellation, which leads to
exclusion of any webpage from the results pool that contains a reference to the
collection of stars given the name Sagittarius.
Fig. 2(b) Search results for Sagittarius
when we use the hyphen symbol to
eliminate the term constellation
from our results pool.

7. Problem 3: Searching for news or information from a particular period of time.
Query: PIA crash incidents between August 1979 and December 1984. (news)
Solution: Using timeline feature. (fig. 3)
Enter the period of time for
which the information of
PIA crash incidents is
required to get results.
Entering the given Query in
the search engine
(ordinarily) gives results
regarding various crashes
of the PIA including those
which do not fall into the
period of time specified.
Fig. 3

8. What’s Happening:
Normally when we enter ‘ PIA crash incidents between August 1979 and
December 1984’ in the search engine, we get news articles on incidents that
belong as well as incidents that don’t belong to the specified time period. Also,
use of ‘between’ doesn’t ensure that the results pool will contain news reports
from within the specified time period. In such cases, we use Google search tools,
specifically, the timeline feature which will ensure that only news from the
specified period is shown as a result.
Problem 4: Searching for webpages containing exactly all of the search terms
Solution: Use of Quotation marks (“”)
Queries: Everything is fair in love and war [fig. 4(a)], “Everything is fair in love
and war” *fig. 4(b)].
Fig . 4(a) Search results for
first query.

9. What’s happening :
When we search for ‘Everything is fair in love and war’, we get results like ‘All’s
fair in love and war’. Both of these have essentially the same meaning. The
replacement of ‘Everything’ with ‘All’ is known as stemming, a default process
performed by the Google search engine in which it displays results which contain
synonyms or variants of certain search terms. This process is stopped by use of
quotation marks on our query. The use of the quotation marks allows only those
results to be shown which contain the phrase ‘Everything is fair in love and war’
exactly but not necessarily as a complete phrase.
Fig. 4(b) shows the results when
quotation marks are added to the
first query.

10. Problem 5: Searching for complete information when we are only given part of
the information to use as a search term.
Solution: Use of asterisk (*)
Queries: Fear of a itself [fig. 5(a)], Fear of a * itself [fig. 5 (b)].
(Quote of J.K. Rowling, author of Harry Potter: ‘Fear of a name increases fear of
the thing itself.’)
Fig. 5 (a) Search for first query does not generate
results relevant to you.
Fig. 5 (b) Search for first
query with the use of
asterisk gives webpages
that contain the quote
required.

11. What’s happening:
When we search for the required quotation using the search terms ‘fear of a
itself’ , we get webpages that give information on movies. By combining the
asterisk with the initial query, we specify that we are searching for a sentence or a
phrase rather than individual terms. It also shows that we are missing a portion of
the quote or dialogue required. This should be used when you can only recall a
portion of the information required.
Problem 6: Expanding your search results pool without using synonyms or
variants of the search terms.
Solution: Use of the Tilde symbol (~)
Query: Biology is ~tough [fig. 6]
Fig. 6 shows results when
we search for ‘ Biology is ~
tough’.

12. What’s Happening:
When we perform the search with the words ‘Biology is tough’, we mostly get
webpages that contain all three words. In order to expand our results pool and to
select the information we need from a larger variety of webpages, we would
usually type in synonyms for particular search terms (in this case the word
‘tough’). This can be time consuming as individual searches have to be performed.
To prevent this, we use the tilde symbol (~). Placing this symbol before a
particular search term allows the Google search engine to give us a variety of
results. As seen in figure 6, searching for ‘Biology is ~tough’ gives results which
contain the sentences ‘Biology is hard’ and ‘Biology is difficult’, that essentially
have the same meaning as our query.
Problem 7: Searching for a particular file type.
Solution: Using the Google ‘filetype:’ feature.
Query: ‘Earthquake facts filetype:xls’ [fig.7]
Fig. 7 shows search results for
query no. 7, the user requires
facts organized in the form of
a table.

13. What’s happening:
When we search simply for earthquake facts, we get our results in various
formats such as .pdf, .doc, .html etc. However, a .pdf format may not display the
facts as clearly as, e.g. , a spreadsheet document. In order to get results that
specifically show the spreadsheet format, we add ‘filetype: xls ‘ to our query.
Problem 8: Converting units or currencies without physical use of a calculator or
physical calculation.
Solution: Use of Conversion feature from Google search engine.
Query: 1 GBP(British Pound) in USD (US Dollars), 24 in (inches) in ft (feet) both [
fig. 8].
Fig. 8 (above) conversion of pounds to
dollars; (below) conversion of inches to
feet.

14. What’s happening:
Conversion is made easy by using the names of units and currencies along with
numbers and entering them as search terms into the search box. Google search
engine immediately identifies the given format and displays conversion as shown
in figure 8. This is done when conversion through lengthy physical calculation is
not required.
Problem 9: Searching for similar webpages without searching for each site
individually
Solution: Using the ‘related:’ feature
Query: related: www.facebook.com [fig. 9].
Fig. 9 shows results that have are
similar to each other in function.

15. What’s happening:
When we use the ‘Related:’ function, we get webpages or websites that
essentially have a similar built or purpose. As shown in figure 9, websites related
to Facebook, a social networking site, include myspace, twitter, youtube and hi5.
All of these sites fulfill the purpose of social networking and thus are related to
each other in that respect. We can use the ‘related:’ function to verify and
validate same information from various sites.
Problem 10: Finding a site when you remember its URL address only partially
Solution: using ‘ inurl: ’ function
Query: ‘inurl:Android4.0’ [fig. 10 ].
Fig. 10 shows results for
‘inurl:android4.0’. Android 4.0 appears
in all the URL addresses listed.

16. What’s happening:
Using the ‘inurl:’ function, we limit the search results to only those webpages that
contain our keywords in their URL addresses. Such webpages according to
statistics contain more relevant information on our search terms when compared
to webpages that contain our search terms in their contents only.
As these 10 examples show, the Google search engine is more powerful than the
average search engine. Among other features of the Google search engine are:
1. ‘define: …’: definition of a search term is generated instead of using an
online or paperback dictionary for the purpose.
2. ‘+’: Used to perform a force search on all the search terms instead of
focusing on certain keywords.
3. ‘Weather’ : Entering this along with the name of a city and a country, gives
a weather forecast of that location.
4. ‘Time’ : using this along with the name of a city or country gives the local
time of that area.