Pages

19.8.11

4.2.3 Using a search engine more effectively

The search shown in Figure 9(b) is an example of how to use a search engine in a simple way. However, one of the problems with finding information on the web is that there is so much! And not all of it is relevant to what you want. My search for ‘rugby’ and ‘wales’ using the Google search engine yielded about 420,000 results or ‘hits’ (see the information contained in the blue strip on Figure 9(b)). The first few sites listed will probably tell me what I want to know. But what about all the others? Are they all about the game of rugby in Wales?
The answer is ‘no’. A website about rugby in New South Wales, Australia also appeared as a result of this search. Google didn't make a mistake since the site contains the chosen keywords. However, it wasn't smart enough to distinguish between Wales and New South Wales.
If you are just looking (‘surfing’) for information in a general way, too much information isn't always a problem. Where it becomes irritating and counterproductive is when you are looking for some quite specific information.

Example 4

Suppose you're interested in genealogy, and your surname is Bird. If you search on the web by typing in the keywords ‘bird’ and ‘family’, the web server will return every website it finds with those two words in it, so you'll probably find scientific and hobby sites on bird ‘families’ such as the passerines! It's clearly not what you want, but do you need to examine all the websites returned (which could run into hundreds) to find the one you're looking for?
The answer is that there are ‘tricks’ that you can use to narrow down your search to eliminate at least some of the things you aren't looking for. Each search engine has its own ‘tricks’, though the concepts of making more targeted searches are common to most search engines. Search engine screens will generally have a selectable topic called something like ‘Advanced Search’ or ‘Search Tips’.
One obvious trick is to choose your keywords carefully. The more specific the keywords you choose, the more likely you are to get what you want. For example, if you want to find information on antique chairs, typing in just the keyword ‘antique’ will return all websites that use the word antique, and typing in the keyword ‘chair’ by itself will return all websites that use the word chair. But typing in both keywords will only return websites that use both words. The more keywords you add, the more targeted will be the websites returned to you. So adding ‘British’ to ‘antique’ and ‘chair’ will only return websites that have all three words in them.

Exercise 10

How could you adapt this trick of using more keywords to help you look for the Bird family?

Discussion

You could choose to enter the keywords ‘bird’ and ‘genealogy’ (the study of family lineages). This will almost certainly eliminate websites about storks and flamingos, or you could add an additional term to ‘bird’ and ‘family’ by specifying ‘bird family history’.

Interestingly, if you have misspelled the keyword ‘genealogy’ as ‘geneology’ some search engines will not match it to websites containing the term ‘genealogy’. Others will respond with the closest word possible. Google, for example, will respond to ‘geneology’ with the message ‘Did you mean genealogy’ together with some websites related to genealogy. Some search engines can't match ‘family’, say, with its plural ‘families’. So if, in a particular search you don't get any matches (called hits), one strategy is to try making plural keywords singular and vice versa. Also remember to check your spelling carefully.
Another useful strategy is to look for phrases rather than individual words. In Exercise 10, I mentioned that you might use ‘bird family history’ to look for information on the Bird family. This might yield a response that includes anything about the animal ‘bird’ using the scientific term ‘family’ and any use in any context of the word ‘history’. However, if you were to enclose the words ‘family’ and ‘history’ in quotation marks (as ‘family history’), the web server will only return websites that contain the word ‘bird’ and the phrase ‘family history’.

SAQ 5

  1. What is a search engine? How does it differ from a browser?

  2. In carrying out a web search, how many computers (at least) are involved?

  3. What makes a computer actually do work?

  4. In what way is a gateway useful?

    Answer

    1. A search engine is a computer program that uses keywords to help users locate websites containing information they want.

    2. At least two are involved: the user's computer (the client) and the web server.

    3. A program of instructions, stored in the computer, called a computer program.

    4. A gateway provides a pre-chosen set of links on the web for a particular topic. Instead of searching the whole of the web for information, a gateway provides a very focused means of getting information that usually has been compiled by an expert.





No comments:

Post a Comment