Sources of Information PT2

1. Sources of Information PT2 Electronic sources

2. Electronic resources Learning Objectives • Internet • Definitions and history of internet • Types of internet protocols • Browsers and navigation • Internet search services • Online databases • Types of databases

3. The Internet • A global network connecting millions of computers. • A collection of vast information sources of interlinked computer networks • Network of Networks • numerous networked computers connected together. • No one in charge of Internet; organizations develop technical aspects of network and set standards

4. History of the Internet (1) • Began September 1 1969 under auspices of Advanced Research projects Agency (ARPA). • Dubbed ARPANET began with connection of one computer at UCLA college campus to an AT&T carrier service network. • By end of year, ARPANET connected computers at four locations • end of 1970, 13 sites ; end of 1973 ARPANET grown to forty sites and international in scope. • In 1973, Vinton Cerf and Robert Kahn and supported by ARPA, established specification of transmission control protocol. (TCP)

5. History of the Internet (2) • 1970s universities began using Internet Protocol to connect local networks to the ARPANET. • Access to Pentagon’s computers on ARPANET tightly controlled, but university computers were permitted to communicate freely with one another. • January 1978, TCP re-engineered into two parts : TCP and IP • By January 1983, all networks required to utilize the TCP and IP protocols for data transmission.

6. History of the Internet (3) • diversity of use posed security risks and in 1983, the military segment of ARPANET broke off and became MILNET • In 1986, National Science Foundation (NSF) began NSFNET, a backbone that connected nation’s five supercomputer centers at high speed. • In 1995, NSFNET reverted to a research network and officially decommissioned. • The Internet now private commercial enterprise, consisting of network of high-speed backbones maintained by carriers and Internet service providers. • Currently, consortium of research universities working in partnership with industry and government to create even faster network named Internet2.

7. Types of Internet Protocols Internet consists of protocols which allow users to search for and retrieve information Protocols - formal agreements on form and style of communication • assure reliable information transfers • ensure clear and unambiguous communications. • Transmission Control Protocol/Internet Protocol (TCP/IP). • Defines rules and procedures for transmitting information • Information transmitted in packets • Each packet contains addressing that identifies which computer sent packet and which computer will receive it

8. Protocols (2) • packets also contain sequencing information that specifies order for reassembling when packets arrive at destination • Message too long to fit in one packet, data gets divided into more than one packet. • IP stands for Internet Protocol • IP governs addressing • Every computer on Internet has unique IP address. • IP address consists of four numbers separated by periods. For example: 140.147.249.7

9. Protocols (3) File retrieval protocols • earliest ways of retrieving information • View names of files stored on serving computer, but no graphics and sometimes no description of a file's content • Need advanced knowledge of files sought.

10. Protocols (4) • FTP (File Transfer Protocol)one of first Internet services developed • allows users to move files from one computer to another • Using FTP program, user can logon to remote computer, browse through its files, download or upload files • can be any type of file, user allowed to see file name • no description of file content • Encounter FTP protocol if you download any software applications from World Wide Web • Many sites that offer downloadable applications use FTP protocol.

11. Protocols (5) • Communications Protocols email, newsgroups and chat • messaging protocols allow users to communicate both asynchronously and synchronously (as with chatting in "real time"). • Emailmain computer acts as a "post office" by sending and receiving mail for those who have accounts eg. email software applications (MS Outlook, Eudora, etc.) or from Web based email accounts (Yahoo, Hotmail). • Email - example of asynchronous Internet communication. • Email - provides the ability to access email lists

12. Protocols (6) • Listervs • Listserv -“list server” built on top of email protocol • work like electronic mailing lists, sending email messages to people whose names are on list. • join by emailing message to it saying you want to subscribe. • subscribe by filling out Web form at listserv’sWebs site • after subscription, whenever someone sends email to listserv, receive copy in your email. • Likewise, when you send email to listserv, everyone on listserv receives copy of your message. Eg. Information literacy listserv

13. Protocols (6) • Usenet bulletin board or an email list without subscription. Anyone can post message to or browse through Usenet newsgroup • Usenet messages are retained on serving computer only for a predetermined length of time and automatically deleted • email list messages are retained on serving computer until account holder downloads them • NewsgroupsYahoo newsgroupsGoogle newsgroupsInterbulletin newsgroups

14. Protocols (7) • IRC (Internet Relay Chat)allows for synchronous communication: users communicate in "real time" or simultaneously • See response to typed message by several people at same time • requires a special software application that can be downloaded from the Web, generally for free. • ChatInternet Relay Chat (IRC) Help pageAIMGoogle TalkMeebo

15. Protocols (8) Multimedia Information Protocol • Hypertext transfer protocol — a.k.a. "The Web“ • most popular way to provide and obtain information from Internet • Web offers not only access to files to download, but offers a series of connecting hyperlinks. • most distinguishing feature of Web is series of "tags“ used to encode and format text, graphics, animation, sound, and other types of files • Tags called HTML (HyperTextMarkup Language) • HTML files can see the "source" HTML coding for any Web page by choosing to "View Source" from your browser's menu bar. • Most browsers allow for access through FTP, Gopher, telnet, and email as well as through the hypertext transfer protocol,

16. Browsers and Navigation • Browser – application to view files on World Wide Web. • text or terminal-based browsers (such as Lynx) that allow you to view only text of file on Web. • Most browsers now graphical browsers to view text, graphics, other multimedia information. • most widely used MS Internet Explorer , Netscape, Firefox. • some Web pages created for specific browsers, Web pages may look different when accessed by different browsers.

17. Navigation • Uniform Resource Locator (URL) • "address" of computer connected to Internet. • address or location box at top of browser. • general format of Web address: • http://www.whitehouse.gov/ • http - "hypertext transfer protocol", protocol for World Wide Web • Other eg. ftp://12.456.789 OR gopher://gopher.uzxy.edu • first part of URL before colon tells browser what type of protocol to use.

18. Navigation (2) • After first dot in URL, is name of particular computer followed by another dot known as domain (.com, .edu, .gov, etc.) • domain indicates type of group or organization using address. • .comCommercial site. information provided by commercial interests is generally going to shed positive light on product it promotes. • eduEducational institution. Information from sites within this domain must be examined very carefully. Could be students’ personal web sites • .govGovernment. information is considered to be from credible source.

19. Navigation (3) • .orga non-profit organization. information in these types of sites is credible and unbiased, but there are examples of organizations that strongly advocate specific points of view over others • .milMilitary. used by various branches of Armed Forces of the United States. • .netNetwork. acts as a catch-all for sites that don't fit into any of preceding domain suffixes. Information from these sites should be given careful scrutiny.

20. Internet Search Services • vast amount of information available on Internet can be overwhelming. • tools available : search engines or search directories. • Search engines collect information from Web sites and then information into a database. • more information to choose from in search engine, but more difficult to retrieve relevant information. • information in databases collected using computer program (called a "spider" or a "robot") that scans Internet and gathers information about individual documents

21. Internet Search Services (2) • special programs work automatically to find documents • When searching, results listed using relevance ranking. Factors influencing search: • how often your search terms are on the Web page; • where they are located on the page; and, • how many other Web pages link to the page • Many search engines allow Web sites to pay to have their pages listed higher in the results. • Eg. Google, alta vista, Excite

22. Internet Search Services (3) • Use search engines : • finding unique keywords, phrases, quotes, and information buried in the full-text of web pages • want a wide range of responses to specific queries • Note: UNevaluated -- contain the good, the bad, and the ugly -- YOU must evaluate everything you find.)

23. Internet Search Services (4) • Meta search engines • Offer "one-stop shopping" to Internet. Searches several other search engines and directories simultaneously so that you get results from all of them in one place. • Used • when conducting a relatively simple search • when you are not having any luck pulling up documents in your search. • when you are in a hurry • useful in obtaining a quick overview on a subject and/or unique term

24. Internet Search Services (5) Metasearch engines…. • you have an obscure topic • you are not having luck finding anything when you search you want to retrieve a relatively small number of relevant results • Eg. Metacrawler, Ixquick; dogpile

25. Internet Search Services (6) • Search directories - sense of order on information collected; find information relevant to your research topic, but don't offer massive amounts of information that you would find with a search engine. • sites collected are viewed by humans who make decisions about what subject categories the sites might fit into. • Used - best for browsing and searches of a more general nature • good sources for information on popular topics, organizations, commercial sites and products • often carefully evaluated and annotated (but not always!!)

26. Internet Search Services (7) • To see kind of information available on the web in a particular field or area of interest, go to a directory and browse through subject categories. Advantages • organized hierarchically into browsable subject categories and sub-categories • Because of human oversight maintained in subject directories, usually deliver higher quality of content and fewer results out of context than search engines. Limitation – • Unlike search engines, most directories do not compile own databases • Instead of storing pages, they point to them • As a result directorymight continue to point to page that has been moved or that no longer exists • Dead links are a real problem for subject directories.

27. Internet Search Services (8) • Types of Subject Directories • General directories, The Librarians’ Index to the Internetwww.lii.com • Aacademic directories, (infominewww.infomine.com) WWW Virtual Libraryhttp://vlib.org/ • Commercial directories, Yahoo /About.com ; Open Directory http://www.dmoz.org/ • NOTE: Today, line between subject directories and search engines blurring. • Most subject directories partner withsearch engines to query their databases and search web for additional sources, while search engines are acquiring subject directories or creating their own.

28. Internet Search Services (9) • Gateways and Subject-Specific databases • Two kinds of gateways: library gateways and portals • Library gateways: collections of databases and informational sites, arranged by subject, that have been assembled, reviewed and recommended by specialists, usually librarians. • gateway collections support research and reference needs by identifying and pointing to recommended, academically-oriented pages on the Web.

29. Internet Search Services (10) • Use library gateways when looking for high quality information sites on Web. • Eg. • Academic Information • Digital Librarian • Infomine • Internet Public Library • Librarians' Index to the Internet • PINAKES • WWW Virtual Library

30. Internet Search Services (11) • Portals- directories that have been created or taken over by commercial interests and then reconfigured to act as gateways to the web • portal sites not only link to popular subject categories, they also offer additional services such as email, current news, stock quotes, travel information and maps. • Portals (subject directories serving as home pages) • Excite • MSN directory • Netscape • Yahoo! directory

31. Internet Search Services (11) • Subject-Specific Databases (sometimes called "Vortals") databases devoted to single subject, created by professors, researchers, experts, governmental agencies, business interests, and other subject specialists and/or individuals. • Use subject-specific databases when looking for information on a specific topic, e.g., news links, multimedia files, archives, mailing lists, people, job finders, and thousands of databases devoted to specific topics of interest

32. Internet Search Services (12) • Eg. • WebMD (health information) • Educator's Reference Desk (educational information) • Expedia (travel) • Internet Movie Database (movies) • Jumbo Software (computer software) • Voice of the Shuttle (humanities research)

33. Internet Search Services (13) • THE "INVISIBLE WEB" or "DEEP WEB" • large portion of Web that search engine spiders cannot, or may not, index • Includes pass-protected sites, documents behind firewalls, archived material, the contents of certain databases, and information that isn't static but assembled dynamically in response to specific queries. • resources may or may not be visible to search engine spiders, although today's search engines are getting better and better at finding and indexing the contents of "Invisible Web" pages. • To access need to point browser directly at them. That's what many library gateways and subject-specific databases do.

34. ONLINE DATABASES

35. Databases • a collection of information organized to provide efficient retrieval • information could be in any number of formats (electronic, printed, graphic, audio, statistical, combinations) • There are physical (paper/print) and electronic databases. • simple as alphabetical arrangement of names in an address book or as complex as database that provides information in a combination of formats. • Examples: • phone book • address book • Census Bureau data

36. Databases (2) Types of Databases • Bibliographic databases – • Provide descriptive record of item, but item itself is not provided in database • Include such things as author, title, subject, publisher, etc. Information provided called citation. • Sometimes, short summary or abstract also provided. • Eg. Ulrich’s International Periodical Directory, Library of Congress Machine Readable Catalog (LCMARC)

37. Databases (3) • Non bibliographic • distinguished from bibliographic databases by content, style or format. • contain information other than citations to books, journal articles or other publications. • two broad groups: textual databases and numeric databases • A full-text database provides full-text of a publication. • Emerald Database provides not only citation to journal article, but often entire text of article as well • Virtually all databases subscribed by CARLIGH are full-text.

38. Databases (4) • Numeric databases -provide numeric information, eg statistics or demographic information, EIU Country Risks and Forecasts database produced by Economist Intelligence Unit. • Advantages and disadvantages • When librarian is seeking information on a subject that is well covered in one database • negative aspect is when topic is partially covered by several databases, each with its own subject heading, structure, dates of coverage, rules for inclusion • Implies that user or librarian has to search several databases before coming up with answers.

39. Databases subscribed by UG • Agora • American Institute of Physics • American Physical Society • Annual Reviews • BioOne • Cambridge Journals • Chicago Journals • Cochrane Medical Library • EBSCOhost • Emerald • Faculty of 1000 Medicine • Geological Society • HINARI • Institute of Electronic and Electrical Engineers

40. Databases subscribed by UG • Institute of Physics • JSTOR • Mary Ann Liebert Inc • Nature Publishing • Optical Society of America • Oxford English Dictionary • Oxford Journals • Royal College of Physicians • Royal Society • Royal Society Journals online • Royal Society of Chemistry : RSC journals archives • Sage Journals Online • ScienceDirect • Wiley - Blackwell (formerly Blackwell Publishing)

41. Free resources on the Internet • African Journals Online (AJOL)http://www.ajol.info/ • BioMed Centralhttp://www.biomedcentral.com • Database of African Theses and Dissertations (DATAD)Directory of Open Access Journals (DOAJ)http://www.doaj.org ( • Directory of Open Access Repositories (OpenDOAR)http://www.opendoar.org • Google Scholar • Highwire Press • Popline1

42. Activity 2 • Using any four online databases, list five journals (from each of the databases) that are relevant to your course of study.