Popular Search Engines
Popular Search Engines
A search engine is a software system that is designed to search for information on the World Wide Web. The search results are generally presented in a line of results often referred to as search engine results pages (SERPs). The information may be a mix of web pages, images, and other types of files. Some search engines also mine data available in databases or open directories. Unlike web directories, which are maintained only by human editors, search engines also maintain real-time information by running an algorithm on a web crawler.
1) Web Crawling
Matthew Gray’s World Wide Web Wanderer (1993) was one of the first efforts to automate the discovery of web pages Gray’s web crawler would download a web page, examine it for links to other pages, and continue downloading links it discovered until there were no more links left to be discovered. This is how web crawlers, also called spiders, generally operate today.
2)Indexing and Ranking
When a web crawler has downloaded a web page, the search engine will index its content. Often the stop words, words that occur very frequently like a, and, the, and to, are ignored. Other words might be stemmed. Stemming is a technique that removes suffixes from a word to improve the content of the index. For example, eating, eats, and eaten may all be stemmed to eat so that a search for eat will match all its variants.
3) Rank Optimization
Search engines guard their weighting formulas as a trade secret since it differentiates their service from other search engines, and they do not want content-producers (the public who produces web pages) to “unfairly” manipulate their rankings. However, many companies rely heavily on search engines for recommendations and customers, and their ranking on a search engine results page (SERP) is very important. Most search engine users only examine the first screen of results, and they view the first few results more often than the results at the bottom of the page. This naturally pits content-producers in an adversarial role against search engines since the producers have an economic incentive to rank highly in SERPs. Competition for certain terms (e.g., Hawaii vacation and flight to New York) is particularly fierce. Because of this, most search engines provide paid-inclusion or sponsored results along with regular (organic) results. This allows companies to purchase space on a SERP for certain terms.
- The Internet is a net consisting of complex network of computers connected by high speed communication technologies.
- The Internet has penetrated and benefited every field – be it education, sports, news, business, etc.
- A web page can be designed using HTML.
- The Internet has converted the world into a global village.
- The Internet has led to faster globalisation. A web page is an electronic document that we can see on the Internet.
- Web browser is software required to view web pages.
- Mosaic was the first web browser.
- www is stand for World Wide Web.
- Electronic mail can be sent and received through any e-mail account.
- Downloading is saving of files from the Internet to our computer.
- Attachments are the extra files that we can send with our email.
- E-commerce stands for electronic-commerce which means buying and selling over the Internet.
- M-commerce is an emerging field which stands for mobile commerce.
- Teleconferencing is having online conference with the facility of exchanging thoughts using an audio.
- Videoconferencing means having online conference with the facility of seeing and listening to other participants.
- Telecommunication is the use of electronic system to send and receive voice, data and video messages.
- Broadly there are five components of communication system, namely information/ message, device, application, protocol and network.
- Voice communication requires telephone instruments like telephone, mobile or VoIP phones for PSTN, wireless or data network.
- Data communication allows transfer of information and remote management of devices.
- Data communication is undertaken by directly connected computers, printers, etc. in a Local Area Network.
- Long distance data communication is done through point to point connections using PSTN or wireless networks.
- Broadcasting of audio and telecasting of video service such as radio and television is done through wireless links.
- Ethernet is the most popular LAN technology for data communication which provides communication speed up to 10Gbps.
- Internet Protocol (IP) connects the computer across similar or diverse networks.
- In IP, data packets are transmitted in packets containing unique IP addresses for the source and the destination.
- IP automatically routes the packet to its destination through any available path.
- Convergence of technologies is required to meet the next generation unified applications where all the three forms of data are required to be transmitted simultaneously.
- IP is internationally accepted protocol through which all different forms of data can be communicated.
- The approach to convergence is to make all components of communication systems IP enabled.
- While trying to achieve convergence, effort is on to use existing infrastructure with partial upgradation.
- Broadband and IPTV are two next generation technologies which use PSTN to provide unified services for voice, data and video.
- VoIP is a data communication technology which allows IP phones and computers to connect to telephones through PSTN and mobile networks.
- Unified messaging system is provided by web service providers which can be used to access multiple services like e-mail, chat, call and entertainment from a single computer system with Internet connection.
- Standardisation is very important for interoperability of various components in any system,
- There are organisations which develop standards, rules and specification for a product that the manufacturers have to meet.