Chapter 5 Searching the web

Search engine

A computer program that gathers and indexes documents, and then searches the database and retrieves documents based on a match with the query.

search engine generally has four main parts (or components) that work together

1. Web Crawler (Spider/Robot)

• An automated program that browses the internet systematically.

• Collects web pages, follows links, and brings data back to the search engine.

• Example: Googlebot is Google’s crawler.

2. Indexing System

• Organizes and stores the information collected by the crawler.

• Builds a massive database (index) so pages can be found quickly.

• Works like the index at the back of a textbook, but for the whole web.

3. Query Processor (Search Algorithm)

• The part that interprets your search (keywords, phrases, questions).

• Matches your query with the best results in the index using ranking algorithms.

• Example: Google’s PageRank helps decide which pages appear first.

4. User Interface (Results Display)

• What you see when you interact with the search engine.

• Provides the search box, suggestions, filters, and the results list.

• Example: The Google search bar and results page.

News search engine

A search engine with a fast rate of update, specifically suited to news items.

Google Scholar

A search engine that specialises in scholarly literature.

Current awareness – alerts

Google Alerts Many search engines allow you to set up an alert service. This means that as soon as new documents on your chosen topic are added to the database, you will be informed.

Ubiquitous computing

means computing everywhere. Other common names for this phenomenon are pervasive computing and the Internet of Things

Directory

Lists of names of people living in a particular area, organisations operating in a particular field or individuals in a particular profession.

Filtering

Narrowing your search by specifying fields in which the search term should appear.

Internet of Things

A network of physical devices with sensors and software that are connected to each other via the internet and exchange data.

Metasite

Sites about sites. Metasites build databases of search engines and databases of databases.

World Wide Web

The world wide web (www) is the part of the internet that is accessible through a browser.