Transcript The Internet

The Internet and
the World Wide
Web
Slide 1
What is the Internet?
• It is a vast network of computers that connects millions of people
all over the world.
• It is a collection of hardware and software in the form of a
worldwide network.
• A network is simply a collection of computers that support the
sharing of information, software & hardware devices.
• An Internet service provider (ISP) is a company that provides
individuals, organisations, & businesses access to the Internet.
Slide 2
Computers on the Internet
• There are two basic types of computers on the Internet:
– Servers
– Clients
• An Internet server computer (also known as an Internet
host computer) is a computer that provides information &
services to other computers & Internet users.
• There are different types of severs such as mail servers,
FTP servers, etc.
• A web client is essentially the computer you use to access
information on the server.
Slide 3
Human communication
• When we talk to each
other we use a
language- for example
English, Kiswahili or
Arabic.
• We also follow certain ‘communication protocols’ or
rules- for example when someone is speaking to you,
you usually do not speak at the same time.
• Can you think of other rules for communication
between people?
Slide 4
How is information communicated
on the internet?
• The internet also has various languages and
‘communication protocols’
• A communication protocol is a set of rules that
computers follow to transfer information. These
protocols allow different computers to communicate
effectively.
• Web pages, are written in Hypertext Markup Language
(HTML)- this is the language
• They are communicated according to Hyper Text
Transfer Protocol (HTTP)- this is the communication
protocol
Slide 5
Types of protocols
• http-hypertext transfer protocol
– It supports the movement of information on the WWW
• TCP/IP-transport control protocol/Internet protocol
– A basic communication protocol that makes the Internet to
work.
– It defines the rules that allow various computers to
communicate across the Internet.
• ftp-file transfer protocol
– Allows you to transfer files of information from one
computer to another.
Slide 6
How do you get connected
to the internet?
Slide 7
You need 4 things to get connected
on the Internet
1. A computer
• May be a notebook, a desktop, etc.
2. An Internet service provider (ISP)
• Includes commercial ISPs, free ISPs, your institution, or your
place of work
3. A modem
• A telecommunication device that allows you to connect your
computer to another or to a network of other computers.
4. Communications software
• Web browsers and connectivity software. Web browsers
allow you to access information on the Web e.g. Internet
Explorer, Netscape, or Mozilla
Slide 8
Who uses the Internet?
The Internet has only been widely used since about 1995 with the
Fast factsof...the 'World Wide Web' but its use has been increasing
availability
– ever
By 1998
1.5 million Web pages born daily
rapidly
since:
– By 2001 there were over 500 million users of the Internet
– In 2003 Google performed 250 million searches per day!
– In 2005 Google claims to search over 8 million pages of the
Internet.
– In December 2009 a survey from Netcraft (a company who provide
Internet research data) had responses from 233,848,493 sites.
•
Slide 9
Slide 10
BUT…
• The Internet is completely uncontrolled. Anyone can
publish anything, letting you find ... well, almost
ANYTHING at all!
• The Internet is also completely DISORGANIZED just like a filing cabinet up-ended into a heap on the
floor.
•There is no structure, no
catalogue, no comprehensive
index, no guide to what
information might be there.
•Understand the Internet
better, and you will search
more successfully for useful
information every time!
Slide 11
Types of information found on the Internet
• There are many types of information on the Internet.
• Different Web sites have been created by different
people or organizations, with different objectives.
• Can you think of THREE
different types of information
that might be on the web?
• There are many different
TYPES of Web sites created
on the Internet for different
REASONS.
Slide 12
Websites
•
•
•
•
•
•
•
•
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News, weather and current affairs e.g. CNN, BBC, Aljazeera. These are profit making and
aim at spreading information.
Government Information- e.g. the Armed Forces, NASA, statistics e.g. Government, The
Whitehouse. These are non-Profit and they provide information to citizens.
Consumer Information- e.g health, cars, travel, new products... selling a product or service
for profit.
Religious- all denominations e.g. The Islamic religion,
Non-governmental organisations- could be big or small, could provide reliable information
or could be bias
Education- schools, universities and colleges. e.g. Kwame Nkrumah University of Science
and Technology. These are non-profit or profit making
Entertainment- e.g. music, movies, games and media personalities e.g. TV
Personal Information or viewpoints- from individuals or families, to large organizations
and groups e.g. Family histories, Associations, Clubs.
Research and publication- including research that may not yet be published elsewhere e.g.
Current Research.
Slide 13
Search Engines
• Search Engines provide us with the ability to
search the vast resources of the Internet
• But WHAT is a Search Engine, and are they
all the same?
– Search Engines are used to find all types of information and
media on the Internet.
– Search Engines provide lists of Web sites.
– Each Search Engine searches differently and finds different
information.
– NO single Search Engine will search the entire Internet.
Slide 14
Search Engines (cont)
– When you use a Search Engine it seems like you are directly
searching the entire Web, but that's not really what happens.
You are really searching a database or index of URL links.
– You can only find links to sites that are included in the
Search Engine's index.
– These links may have been collected by a program called a
"Web crawler", or by a human evaluator.
– Quite often links are displayed because someone paid a fee
to have their web site included.
– You may be surprised to read that there are hundreds of
Search Engines available to use on the Internet!
– How many Search Engines do YOU usually use?
Slide 15
Live search engines
• A LIVE Search Engine is fully automated. It carries out
your search by using 'bots' or 'spiders' (computer
programs) which automatically search the Web for the
search string (or words) you have typed in. There is NO
human indexing.
• It often returns you LARGE lists of results, but because it
uses keyword matching only, the RELEVANCE may be
lower, and the list of results includes very brief information
for each Web site listed (making it harder to sift through for
what you are after)
• It usually gives you up-to-date results, and many give you
the option (in 'Advanced Search' screens) to only search
for a particular date range.
• Examples include Google, Bing or AllTheWeb.
Slide 16
Directories or Subject Guides
• A DIRECTORY or Subject Guide organizes pre-selected
Web sites into subject areas. Directories are created by
human indexing.
• It allows you to search for 'search strings' or words, just
like a LIVE Search Engine, but will also let you click
through a menu (or a hierarchy) to find information on your
topic. For example, you could select more specific
subjects, like: Computers - - Internet - - Web development
- - Web graphics
• It usually gives you a SMALLER results list, but the
results will be much more SPECIFIC for your topic!
• It is compiled and indexed by humans (which takes time)
the information retrieved is often not up-to-date.
• Examples include Google Directory and Eldis.
Slide 17
Meta Search Engines
• A META Search Engine searches other Search Engines. It
will search several LIVE Search Engines (such as Google,
Yahoo and Ask Jeeves) at the same time.
• It gives you a small result - usually 5-10 results - from
each Search Engine looked at.
• It is fully automatic. There is NO human indexing or
involvement in a Meta tool.
• It allows you to do a QUICK and BROAD browse of what
information may be on the Internet for your topic. It is as
up-to-date as the LIVE Search Engines that it uses.
• Examples include Dogpile and Metacrawler.
Slide 18
What search tool should I use?
• Live search engine?
• Directory/Subject Gateway?
• Meta-search engine?
Slide 19
What search tool should I use?
Use a LIVE Search Engine when:
–
–
–
You need up-to-date information
There is not much information on your topic, and you need a comprehensive search to get a broad
picture
The Web sites found may not be as relevant or contain reliable formation, so sifting through long lists
and evaluating all information that you find is essential!
Use a DIRECTORY or Subject Guide when:
–
–
–
There is lots of information on your topic, and you would like to narrow down your search
You need more relevant and reliable information which has already been indexed and evaluated by
human indexers
The Web sites found may not be as up-to-date, but will be more selective and relevant to your
research topic. Evaluating the information you find is still necessary, but the information given to you
in the results list is longer and easier to select relevant information from.
Use a META Search Engine when:
–
–
–
Slide 20
You need a brief overview of your topic, and would like to browse what might be available on the
Internet
You would like to read generally about your topic
The Web sites found will be up-to-date, but will need careful evaluation of the information retrieved.
Many META tools seem to have a high number of ‘sponsored’ results in their lists too, so be wary of
these and don't waste your time!
Quiz!
• What is the internet?
• What is the world wide web?
• Name four things you need to access
the internet?
• Name three different types of search
engine?
Slide 21
Any Questions??
Slide 22
Search
strategies
Slide 23
Search techniques
– Boolean operators are AND, OR, NOT and NEAR
– They are used to combine search terms when
doing research
– You can also use brackets to combine boolean
searches
– You can use inverted commas to find phrases
– Finally you can use truncation to find related words
Slide 24
And
• Would everybody wearing a tie, please stand up
# _____
• Would everybody wearing ‘black shoes’ please
stand up
# _____
• Would everybody wearing a tie and ‘black shoes’
please stand up
# _____
Slide 25
Venn Diagram of AND
Tie
Slide 26
‘Black
shoes’
AND Explained
• Using the operator AND between keywords will limit
the results of a search because all the keywords
have to be present in order for an item to be
retrieved.
• If you enter two words without a boolean operator,
most search engines assume you mean AND
• For example if you search for
– Cheese France
• The results you get will be the same as if you search
for
– Cheese AND France
Slide 27
Or
• Would everybody wearing a tie, please stand up
# _____
• Would everybody wearing ‘black shoes’ please
stand up
# _____
• Would everybody wearing a tie or ‘black shoes’
please stand up
# _____
Slide 28
Venn Diagram of OR
Tie
Slide 29
‘Black
shoes’
OR Explained
• Using the OR operator results in either or
both of your search terms appearing in your
results.
• Using the OR operator will result in a larger
number of retrieved items and therefore
expands the search.
Slide 30
NOT
• The NOT (or AND NOT) operator forbids the
word after it from appearing in the items
resulting from your search.
• Would everybody wearing a tie but NOT black
shoes, please stand up
Slide 31
Venn Diagram for NOT
Tie
Slide 32
‘Black
shoes
NOT Explained
• Not helps to limit your search because it
takes out a category of undesirable results.
• NOT thus narrows or limits a search by
excluding the keyword immediately following
it.
• In some search engines (including Google)
you use a minus sign before a word instead
of NOT
• For example to search for information on Iraq
NOT war in Google you would use Iraq -war
Slide 33
If you search for:
Cell phone
Without quotes around the two words, what kind of
search is that?
That kind of search might bring back a page that says
“James was on the phone when police arrested the
members of a terrorist cell.”
And that would not be what you wanted . . .
Slide 34
Phrases
• If you want to search for a specific phrase you
can use inverted commas: ‘’
• For example, to search for cell phone you can
use ‘cell phone’
• You may have also noticed that earlier I used
the phrase ‘black shoes’
• Can you give examples of other phrases that
you might want to search for?
Slide 35
Truncation
• Use * to ‘truncate’ or shorten a word so that
you find related words
• For example, hosp* would find hospital,
hospitals, hospitalisation, hospitality etc.
Slide 36
Synonyms
• Google has introduced a special "tilde"operator that lets you search for synonyms.
• If you place the tilde sign ("~") immediately in
front of a keyword, Google will replace that
keyword with a list of words with a similar
meaning, thus extending your search.
• For instance, if you search for ~football you
would also find entries which mention soccer
Slide 37
Be sure to use proper search structure
• What would the following search bring up?
Dogs AND ((rabies OR rabid) NOT (domestic OR Pet) )
– The search will look for the words rabies and rabid
– Then domestic and pet
– Then remove all results that contain the words domestic or pet
from the results
– Then remove anything that does not contain the word dog from
the results
Slide 38
Practice makes perfect
•Some search engines are cleverer than others!
•For example, if you search for contain on google, it will
automatically also search for contains, container, containment etc
• If you search for multiple words
on google, it may still give you a
result which is missing one word
if it seems to be relevant
• Other search engines and
databases will ONLY search for
exactly what you have entered
• You need to experiment with
each search engine to find out
how to use it best
Slide 39
Any questions?
Slide 40
Internet tips and
tricks!
Slide 41
Bookmarking
• Bookmark useful sites so that
you can go back to them easily
• Go to the Bookmark (or
Favourites menu) and click to
add
• Click Organise Bookmarks (or
Favourites) to sort them into
folders
Slide 42
Maps
• Map websites such as Google maps can be
used to view maps or satellite images
• You can use them to find out how to get to a
meeting, to see what countries border
another country, to find a hotel in a new city
etc.
Slide 43
Slide 44
Google translate
• You can use Google translate to search for
websites in other languages- even if you don’t
speak the language
Slide 45
Slide 46
Wikis
• Wikis are websites which a group of people
can edit
• The most famous is Wikipedia- an online
encyclopedia which anyone in the world can
add to
• It is a very useful starting point to find out
about a new topic
• BUT be careful to check facts- it is not always
accurate and may have been edited by
someone with a biased viewpoint
Slide 47
Any questions?
Slide 48
•
•
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Slide 49