Lecture 2Accessibility of Information on the Web

Lecture 2: Accessibility of Information on the Web Genetic Data and the Internet Searching for a Web Page Accessibility of the Information on the Web 1 Internet?  a world-system that links millions of individulal computers local networks •university •research lab. •commercial organization •governmental o instant communication between computers 2 World Wide Web (WWW)  a way of using the Internet through a web browser program.  easy reach to desired information (sound, video, text, sequence of a gene, literature, etc)  like a library and public notice board of unlimited size with unlimited access. 3 Publicly indexable WWW contains  1.2 billion pages (2001)  9 terabytes (1012) of text  5 million servers %6 scientific • university, project and scientists homepages •reprints, technical reports • lournal papers •teaching resources •databases (gene sequences, molecular structures and image libraries) 4 •conferences Search in the Internet  Handicaps  its living; growing, reproducing, changing 5 6 Search Services (Tools) on the Web Search directories  Search engines      Normal Search Engines Meta search engines Image search engines Meta image search engines Most search services are a hybrid of two oe more of them, but more dominant in one area. Yahoo: portal, directory, search engine Portals  Others     Dictionaries Thesauri Encyclopaedias Close familiarity with each of these facilities will greatly assist you when searching for scientific resources on the Web 7 Directories  Directories are organized indexes that allow you to browse through lists of Web sites by subject or topic.  Directories are created by people. 8 Directories  Excellent for browsing  Like visiting a library  Clearly defined subjects 9 How a website is included in a Search Directory?  Hierarchical directory of websites compiled by humans: categories > sub-categories etc. 1. 2. 3. 4. Website owners typically submit a 50-word description of their website for inclusion Volunteer editors approve the website and and post the description under the most appropriate subject category in the directory The ‘human element’ naturally discriminates, therefore weeding out useless websites Many websites are rejected for inclusion 10 Who Creates Directories?     Libraries Nonprofit organizations Universities Dot-Com businesses  but they are probably portals too 11 A Sampling of Directories  Librarians’ Index to the Internet www.lii.org/  Open Directory Project www.dmoz.org  Looksmart www.looksmart.com  Yahoo www.yahoo.com 12 13 14 15 16 Portals  Portals offer a one-stop shopping look.  Portals include e-mail, chat, auctions, news, weather, horoscopes, stock info, and more.  Portals want to be YOUR starting point. 17