2. 1 Course Medical Statistics with Informatics

3. Internet and computer networks

4. Lecture outline Searching Internet –Part 1 : Search engines - in general –Part 2: More about Google search engine –Part 3: Digital libraries Communication and computer networks –Part 4: Communication networks –Part 5:Internet and how it works

5. Searching Internet

6. Part 1: Search engines – in general Source: Tefko Saracevic, Principles of searching (http://comminfo.rutgers.edu/~tefko/Courses/e530/index.htm/)

7. 6 Dictionary definitions Dictionary definitions search COMPUTING (transitive verb) to examine a computer file, disk, database, or network for particular information engine something that supplies the driving force or energy to a movement, system, or trend search engine a computer program that searches for particular keywords and returns a list of documents in which they were found, especially a commercial service that scans documents on the Internet

8. 7 About definition of search engines oh well … search engines do not search only for keywords, some search for other stuff as well and they are really not “engines” in the classical sense –but then mouse is not a “mouse”

9. 8 Your Browser How Search Engines Work (Sherman 2003) The Web URL1 URL2 URL3 URL4 Crawler Indexer Search Engine Database Eggs? Eggs. Eggs - 90% Eggo - 81% Ego- 40% Huh? - 10% All About Eggs by S. I. Am

10. 9 How do search engines work? elaboration crawlers, spiders: go out to find content –in various ways go through the web looking for new & changed sites –periodic, not for each query no search engine works in real time –some search engines do it for themselves, others not buy content from companies such as Inktomi –for a number of reasons crawlers do not cover all of the web – just a fraction –what is not covered is “invisible web”

11. © Tefko Saracevic10 elaboration … organizing content: labeling, arranging –indexing for searching – automatic keywords and other fields arranging by URL popularity - PageRank as Google –classifying as directory mostly human handpicked & classified as a result of different organization we have basically two kinds of search engines: search – input is a query that is then searched & displayed directory – classified content – a class is displayed –and fused: directories have now also search capabilities & vice versa

12. 11 elaboration (cont.) databases, caches: storing content –humongous files usually distributed over many computers query processor: searching, retrieval, display –takes your query as input engines have differing rules how handled –displays ranked output some engines also cluster output and provide visualization at the other end is your browser

13. 12 elaboration… similarities, differences all search engines have these basic parts in common BUT the actual processes – methods how they do it – are based on various algorithms & they differ – most are proprietary with details kept mostly secret but based on well known principles from information retrieval or classification – to some extent Google is an exception – they published their method

14. 13 case of Google developed by Sergey Brin and Lawrence Page while students at Stanford –in the beginning run on Stanford computers basic approach has been described in their famous paper “The Anatomy of a Large-Scale Hypertextual Web Search Engine”“The Anatomy of a Large-Scale Hypertextual Web Search Engine” –well written, simple language, has their pictures –in acknowledgement they cite the support by NSF’s Digital Library Initiative i.e. initially, Google came out of government sponsored research –describe their method PageRank - based on ranking hyperlinks as in citation indexing –“We chose our system name, Google, because it is a common spelling of googol, or ten on hundredth power”

15. 14 coverage differences no engine covers more than a fraction of WWW –estimates: none more than 16% –hard (even impossible) to discern & compare coverage, but they differ substantially in what they cover in addition: –many national search engines own coverage, orientation, governance –many specialized or domain search engines own coverage geared to subject of interest –many comprehensive sources independent of search engines some have compilations of evaluated web sources

16. 15 searching differences substantial differences among search engines on searching, retrieval display –need to know how they work & differ in respect to defaults in searching a query searching of phrases, case sensitivity, categories searching of different fields, formats, types of resources advance search capabilities and features possibilities for refinement, using relevance feedback display options personalization options

17. 16 business model differences several business models public good - have independent budget –e.g. PubMed, Librarians’ Index to InternetPubMedLibrarians’ Index to Internet earn revenue from provision of information –all commercial search engines using search engines to promote their other activities –e.g. telephone directories

18. 17 sponsorship differences need to understand treatment of sponsorship – they influence what they search & how they display results –some list separately results from sponsored sites so you are reasonably clear what is there because it is sponsored & not –some have display-per-pay - showing first sites that paid most & do not even tell you that –some have pay per update of sites imperative to find sources that explain these models for different engines to know what is covered & what are you are getting

19. 18 limitations every search engine has limitation as to –coverage meta engines just follow coverage limitations & have more of their own –search capabilities –finding quality information some have compromised search with economics –becoming little more than advertisers but search engines are also many times victims of spamindexing –affecting what is included and how ranked

20. 19 spamming a search engine use of techniques that push rankings higher than they belong is also called spamdexing –methods typically include textual as well as link-based techniques –like e-mail spam, search engine spam is a form of adversarial information retrieval the conflicting goals of accurate results of search providers & high positioning by content page rank

21. 20 meta search engines meta engines search multiple engines –getting combined results from a variety of engines do not have their own databases –but have their own business models affecting results a number of techniques used –interesting ones: clustering, statistical analyses

22. 21 how to find a search engine? variety of resources that list or categorize engines SearchEngines.com search for engines by topic, geography, reference Search Engine Guide engines categorized by topic; other engine information Search Engine Colossus –international directory of search engines by country, topic from 198 countries and 61 territories; engines in choice of languages Phil Bradley’s country based search engines over 2000 search engines from countries all over the globe

23. 22 sample of meta engines - with organized results Dogpile results from a number of leading search engines; gives source, so overlap can be compared; (has also a (bad) joke of the day) Surfwax gives statistics and text sources & linking to sources; for some terms gives related terms to focus Teoma results with suggestions for narrowing; links resources derived; originated at Rutgers Turbo10 provides results in clusters; engines searched can be edited

24. 23 meta search engines (cont.) meta search engines (cont.) Large directory – Complete Planet Complete Planet directory of over 70,000 databases & specialty engines Results with graphical displays – Vivisimo Vivisimo clusters results; innovative – Webbrain Webbrain results in tree structure – fun to use Kartoo results in display by topics of query

25. 24 domain engines & catalogs cover specific subjects & topics important tool for subject searches –particularly for subject specialist –valued by professional searchers selection mostly hand-picked rather than by crawlers, following inclusion criteria –often not readily discernable –but content more trustworthy

26. 25 domain engines … sample domain engines … sample Open Directory Project large edited catalog of the web – global, run by volunteers BUBL LINK selected Internet resources covering all academic subject areas; organized by Dewey Decimal System – from UK Profusion search in categories for resources & search engines Resource Discovery Network Resource Discovery Network – UK “UK's free national gateway to Internet resources for the learning, teaching and research community”

27. 26 domain engines … sample Think Quest Think Quest – Oracle Education Foundation education resources, programs; web sites created by students All Music Guide resource about musicians, albums, and songs Internet Movie Database treasure trove of American and British movies Genealogy links and surname search engines well.. that is getting really specialized (and popular) Daypop searches the “living web” “The living web is composed of sites that update on a daily basis: newspapers, online magazines, and weblogs”

28. 27 science, scholarship engines …sample free access Psychcrawler - Amer Psychological Association Psychcrawler –web index for psychology Entrez PubMed – Nat Library of Medicine Entrez PubMed biomedical literature from MEDLINE & health journals CiteSeer - NEC Research Center CiteSeer –scientific literature, citations index; strong in computer science Scholar GoogleScholar Google - searches for scholarly articles & resources InfomineInfomine - scholarly internet research collections ScirusScirus - scientific information in journals & on the web KOBSONKOBSON –National Library of Serbia access to scientific journals

29. science, scholarship engines …sample free access, but is it legal? Library.nu –previously called ebooksclub.org and gigapedia.com, was a popular linking website. It was accused of copyright infringement and it was shut down by court order on February 15, 2012. According to the takedown notice, it hosted some 400,000 ebooks and allegedly had a revenue of over $10 million. Library Genesis –Considered an alternative to Library.nu –Based in Russia, the site features 800000+ ebook files, in total amounting to over 12 TB -- easily the Library of Congress of the digital world. –And by the way, the website is blocking all US IP addresses, so if that’s the case, use a proxy.

30. 29 science, scholarship engines …sample commercial access an addition to freely accessible engines many provide search free but access to full text paid –by subscription or per item –RUL provides access to these & many more: ScienceDirect Elsevier: “world's largest electronic collection of science, technology and medicine full text and bibliographic information” ACM Portal Asoc. for Computing Machinery: access to ACM Digital Library & Guide to Computing

31. 30 where to find out? information about search engines in sources that have updates, news, tips for searching and more – a MUST for searchers : – Search Engine Watch Search Engine Watch ratings, news, statistics, charts, explanations, tutorials – Search Engine Showdown Search Engine Showdown “The users’ guide to web searching” - run by a librarian, news links, ratings Virtual Chase a site about “Teaching Legal Professionals How To Do Research;,” this section has very good tips and links for consideration of quality on the web

32. 31 where? …. ResourceShelf “Resources and News for Information Professionals,” edited by Gary Price, a librarian & author of Invisible Web – has extensive archive WebsearchAbout not evaluative, but provides news, capabilities, sources, articles about web searching

33. Part 2: More about Google engine Google 201: Advanced Googology a presentation by Patrick Douglas Crispen, Ed.D. NetSquirrel.com http://netsquirrel.com/powerpoint/powerpoint/google_201_20110303.ppt.zip

34. Google 201: Advanced Googology a presentation by Patrick Douglas Crispen, Ed.D. NetSquirrel.com

35. Our Goals Learn how Google really works. Discover some Google secrets no one ever tells you. Play around with some of Google’s advanced search operators. Find out where to get more Google-related help and information. DO ALL OF THIS IN ENGLISH!

36. Part One: How Google REALLY Works Or, at least, how I think Google really works.

37. One Word of Warning For obvious reasons, the folks at Google would rather the Wizard of Oz stay behind the curtain, so to speak. So, what you are about to see on the next few slides are just plain guesses on my part. And, my guesses are probably completely wrong! But they’re pretty. And that’s all that matters.

38. Another Word of Warning I also need to warn you that my guesses use a little bit of algebra, but I promise it is simple algebra. –Well, there is one intimidating-looking equation, but we’ll get to that in a bit. Just remember that, in this case, X > Y > Z, and there can be different values for each variable (X 1 > X 2 … > X n.) I’ve lost you already, haven’t I?

39. How Google Works - Phrases When you search for multiple keywords, Google first searches for all of your keywords as a phrase. I think. So, if your keywords are disney fantasyland pirates, any pages on which those words appear as a phrase receive a score of X. Image source: Google Source: Google Hacks, p. 21

40. How Google Works - Adjacency Google then measures the adjacency between your keywords and gives those pages a score of Y. What does this mean in English? Well … Image source: Google Source: Google Hacks, p. 21

41. How Adjacency Works A page that says “My favorite Disney attraction, outside of Fantasyland, is Pirates of the Caribbean” will receive a higher adjacency score than a page that says “Walt Disney was a both a genius and a taskmaster. The team at WDI spent many sleepless nights designing Fantasyland. But nothing could compare to the amount of Imagineering work required to create Pirates of the Caribbean.”

42. How Google Works - Weights Then, Google measures the number of times your keywords appear on the page (the keywords’ “weights”) and gives those pages a score of Z. A page that has the word disney four times, fantasyland three times, and pirates seven times would receive a higher weights score than a page that only has those words once. Source: Google Hacks, p. 21

43. You Still With Me?

44. Putting it All Together Google takes –The phrase hits (the Xs), –The adjacency hits (the Ys), –The weights hits (the Zs), and –About 100 other secret variables Throws out everything but the top 2,000 Multiplies each remaining page’s individual score by it’s “PageRank” And, finally, displays the top 1,000 in order.

45. PageRank? There is a premise in higher education that the importance of a research paper can be judged by the number of citations the paper has from other research papers. Google simply applies this premise to the Web: the importance of a Web page can be judged by the number of hyperlinks pointing to it from other pages. Or, to put it mathematically [brace yourself – the next slide contains the intimidating-looking equation I warned you about] … Source: Google Hacks, p. 294

46. The PageRank Algorithm Where PR(A) is the PageRank of Page A PR(T1) is the PageRank of page T1 C(T1) is the number of outgoing links from the page T1 d is a damping factor in the range of 0 < d < 1, usually set to 0.85 Source: Google Hacks, p. 295

47. You Can Start Breathing Again I promise there are no more equations in this presentation. I just wanted to show you that the PageRank of a Web page is the sum of the PageRanks of all the pages linking to it divided by the number of links on each of those pages. –A page with a lot of (incoming) links to it is deemed to be more important than a page with only a few links to it. –A page with few (outgoing) links to other pages is deemed to be more important than a page with links to lots of other pages. Source: Google Hacks, p. 295

48. Part One: In Summary Google first searches for your keywords as a phrase and gives those hits a score of X. Google then searches for keyword adjacency and gives those hits a score of Y. Google then looks for keyword weights and gives those hits a score of Z. Google combines the Xs, the Ys, the Zs, and a whole bunch of unknown variables, and then weeds out all but the top 2,000 scores. Finally, Google takes the top 2,000 scores, multiplies each by their respective PageRank, and displays the top 1,000. I think.

49. Part Two: Search engine math I said “no more equations.” I didn’t say “no more MATH!”

50. Google rule #1 Be specific... because if you aren’t specific, you’ll end up with a bunch of garbage!

51. Google rule #2 Use quotes to search for phrases. [Well, not really.] “patrick crispen”

52. Google rule #3 Use the + sign to require an exact match. [Well, not really.] “patrick crispen” +tourbus

53. Google rule #4 Use the - sign to exclude. “patrick crispen” -tourbus

54. Google rule #5 Combine symbols as often as possible (see rule #1). ”patrick crispen” –tourbus +usc

55. Part Two: In Summary 1.Be specific... because if you aren’t specific, you’ll end up with a bunch of garbage! 2.Use quotes to search for phrases. [Well, not really.] 3.Use the + sign to require. [Well, not really.] 4.Use the - sign to exclude. 5.Combine symbols as often as possible (see rule #1).

56. Part Three: More Stuff No One Tells You Google’s shocking secrets revealed!

57. Google’s Boolean Default is AND But there are ways to get around that.

58. Boolean Default is AND If you search for more than one keyword at a time, Google will automatically search for pages that contain ALL of your keywords. A search for disney fantasyland pirates is the same as searching for disney AND fantasyland AND pirates Source: http://www.google.com/help/basics.html

59. Phrases To search for phrases, just put your phrase in quotes. For example, disney fantasyland “pirates of the caribbean” –This would show you all the pages in Google’s index that contain the word disney AND the word fantasyland AND the phrase pirates of the caribbean (without the quotes) By the way, while this search is technically perfect, my choice of keywords contains a (deliberate) factual mistake. Can you spot it? Source: http://www.google.com/help/refinesearch.html

60. Arr, She Blows! Pirates of the Caribbean isn’t in Fantasyland, it’s in Adventureland in Orlando and New Orleans Square in Anaheim. So searching for disney AND fantasyland AND “pirates of the caribbean” probably isn’t a good idea. Image source: http://www.balgavy.at/

61. Boolean OR Sometimes the default AND gets in the way. That’s where OR comes in. The Boolean operator OR is always in all caps and goes between keywords. For example, an improvement over our earlier search would be disney fantasyland OR “pirates of the caribbean” –This would show you all the pages in Google’s index that contain the word disney AND the word fantasyland OR the phrase pirates of the caribbean (without the quotes) Source: http://www.google.com/help/refinesearch.html

62. Three Ways to OR at Google Just type OR between keywords –disney fantasyland OR “pirates of the caribbean” Put your OR statement in parentheses –disney (fantasyland OR “pirates of the caribbean”) Use the | (“pipe”) character in place of the word OR –disney (fantasyland | “pirates of the caribbean”) All three methods yield the exact same results. Source: Google Hacks, p. 3

63. OR, She Blows! Just remember, Google’s Boolean default is AND Sometimes the default AND gets in the way. That’s where OR comes in. Image source: http://www.phil-sears.com/

64. Capitalization Does NOT Matter The old AltaVista trick of typing your keywords in lower case is no longer necessary.

65. How Insensitive! Google is not case sensitive. So, the following searches all yield exactly the same results: disney fantasyland pirates Disney Fantasyland Pirates DISNEY FANTASYLAND PIRATES DiSnEy FaNtAsYlAnD pIrAtEs Source: http://www.google.com/help/basics.html

66. Google Supports Stemming and Wildcard Searches! When you wish upon a *.

67. Stemming and Wildcards Wildcards are characters, usually asterisks (*), that represent other characters. For example, some search engines support a technique called “stemming.” –With stemming, you search for something like pirate* and the search engine shows you all the pages in its database that contain variants of the word pirate – pirates, pirated, etc. But, did you notice I said “some search engines?”

68. Google and Stemming Google doesn’t require a wildcard to stem. When appropriate, Google automatically searches not only for your search terms but also for words that are similar to some or all of those terms. A search for pirate life for me will also automatically include hits for –pirate’s life for me –pirates life for me –Pirated life for me You can turn off stemming with a + or quotes, but not always. Source: http://www.google.com/help/basics.html

69. Google and Wildcards As for wildcards, Google doesn’t offer stemming wildcards but rather offers “full-word” wildcards. For example, if you search Google for it’s a * world, Google shows you all of the pages in its database that contain the phrase “it’s a small world” … and “it’s a nano world” … and “it’s a Linux world” … and so on. Source: Google Hacks, p. 37

70. it’s a * world Most of the hits are phrases because that’s what Google looks for first. Oh, and I defy you to get that song out of your head! Image source: http://themeparksource.com/

71. Wildcards and the Word Limit Google doesn’t count wildcards toward the 32 word limit. For example, Google thinks that though * mountains divide * * oceans * wide it's * small world after all is exactly 10 words long. Source: Google Hacks, p. 19

72. The Order of Your Keywords Matters A me life for pirate’s?

73. How Google Works When you conduct a search at Google, it searches for –Phrases, then –Adjacency, then –Weights. Because Google searches for phrases first, the order of your keywords matters. Image source: Google Source: Google Hacks, p. 20-22

74. For Example A search for disney fantasyland pirates yields almost the same number of hits as a search for fantasyland disney pirates, but the order of those hits – especially the first 10 – is noticeably different.

75. Part Three: In Summary Google’s Boolean default is AND. Capitalization does not matter. Google has a hard limit of 32 keywords. Google supports stemming and wildcard searches. The order of your keywords matters.

76. Part Four: Advanced Search Operators Beyond plusses, minuses, ANDs, ORs, quotes, and *s

77. How Google Finds New Pages Google has special programs called spiders (a.k.a. “Google bots”) that constantly search the Internet looking for new or updated Web pages. When a spider finds a new or updated page, it reads that entire page, reports back to Google, and then visits all of the other pages to which that new page links. Image source: http://www.disobey.com/

78. How Google Finds New Pages When the spider reports back to Google, it doesn’t just tell Google the new or updated page’s URL. The spider also sends Google a complete copy of the entire Web page – HTML, text, images, etc. Google then adds that page and all of its content to Google’s cache.

79. So What? When you search Google, you’re actually searching Google’s cache of Web pages. And because of this, you can search for more than text or phrases in the body of a Web page. Google has some secret, advanced search operators that let you search specific parts of Web pages or specific types of information. Source: Google Hacks, p. 5

80. Advanced Operators Query modifiers filetype: intitle: inurl: site: ~ AROUND(n) Alternative query types cache: link: related: info: Other information needs stocks: define: Google Calculator weather movie

81. Query Modifiers Stuff you can add to your regular searches

82. filetype: filetype: restricts your results to files ending in ".doc" (or.xls,.ppt. etc.), and shows you only files created with the corresponding program. There can be no space between filetype: and the file extension The “dot” in the file extension –.doc – is optional. Source: http://www.google.com/help/faq_filetypes.html

83. Google’s Most Common Filetypes Adobe Flash (.swf) Adobe Portable Document Format (.pdf) Adobe PostScript (.ps) Autodesk Design Web Format (.dwf) Google Earth (.kml,.kmz) GPS eXchange Format (.gpx) Hancom Hanword (.hwp) HTML (.htm,.html, other file extensions) Microsoft Excel (.xls,.xlsx) Microsoft PowerPoint (.ppt,.pptx) Microsoft Word (.doc,.docx) Microsoft Works (wks, wps, wdb) OpenOffice presentation (.odp) OpenOffice spreadsheet (.ods) OpenOffice text (.odt) Rich Text Format (.rtf,.wri) Scalable Vector Graphics (.svg) Text (.txt,.text, other file extensions), including source code Wireless Markup Language (.wml,.wap) XML (.xml) Source: http://www.google.com/help/faq_filetypes.html

84. filetype:extension pirates filetype:pdf pirates -filetype:pdf

85. intitle: Using intitle: restricts the results to documents containing a particular word in its title. There can be no space between intitle: and the following word. You can also search for phrases. Just put your phrase in quotes. Source: http://www.google.com/help/operators.html

86. Title? Pirates of the Caribbean...

87. intitle:terms intitle:pirates pirates -intitle:”walt disney”

88. A Quick Question What would happen if I searched for intitle:walt disney (without the quotes?) Google would look for every page with the world walt in its title AND the word disney somewhere in its body. Remember, the quotes are kind of important if you want to search for phrases using intitle:

89. inurl: Using inurl: restricts the results to documents containing a particular word in its URL. There can be no space between inurl: and the following word. Source: http://www.google.com/help/operators.html

90. URL? A URL is a uniform resource locator, a string that uses a standard syntax to identify an access protocol, location, and identifier for a file or other Internet resource. –http://www.disney.com/http://www.disney.com/ –http://www.google.com/http://www.google.com/ –ftp://wuarchive.wustl.edu/ftp://wuarchive.wustl.edu/ –news:google.public.support.generalnews:google.public.support.general Source: http://search400.techtarget.com/newsItem/0,289139,sid3_gci850,00.html

91. inurl:term inurl:disney pirates –inurl:disney

92. site: Using site: restricts the results to those websites in a domain. There can be no space between site: and the domain. Source: http://www.google.com/help/operators.html

93. site:domain pirates site:disney.com

94. Using site: You use site: in conjunction with another search term or phrase. pirates site:disney.com You can also use site: to exclude sites. pirates –site:disney.com You can use site: to exclude or include entire domains (and, like with filetype, the dot is optional). pirates –site:com pirates site:edu

95. The Curse of the Boolean Default What would happen if you searched for pirates site:edu site:com Remember: Use an OR search to include or exclude hits from multiple sites or domains.

96. Synonyms Using ~ before a keyword tells Google to search for both that keyword and its synonyms. There can be no space between ~ and the keyword. Source: http://www.google.com/help/operators.html

97. ~keyword pirate ~treasure

98. AROUND(n) Using AROUND(n) between two keywords or phrases keyword tells Google to search for pages where those words are no more than n number of words apart. The word AROUND has to be in all caps.

99. term1 AROUND(n) term2 ”johnnie depp” AROUND(5) pirates sheen AROUND(3) sanity

100. Alternative Query Types Stuff you can use if you want to search without using any keywords

101. cache: Using cache: shows the version of a web page that Google has in its cache. There can be no space between cache: and the URL. You can use cache: in conjunction with a keyword or phrase, but few do. Source: http://www.google.com/help/operators.html

102. cache:URL cache:disney.com

103. link: Using link: restricts the results to those web pages that have links to the specified URL. There can be no space between link: and the URL. Source: http://www.google.com/help/operators.html

104. link:URL link:disney.com

105. related: Using related: lists web pages that are "similar" to a specified web page. There can be no space between related: and the URL. Source: http://www.google.com/help/operators.html

106. related:URL related:disney.com

107. info: Using info: presents some information that Google has about a particular web page. There can be no space between info: and the URL. Source: http://www.google.com/help/operators.html

108. info:URL info:disney.com

109. Other Information Needs Did you know that Google can look up stock quotes, dictionary definitions, and even the answer to math problems?

110. stocks: If you begin a query with stocks: Google will treat the rest of the query terms as stock ticker symbols, and will link to a Yahoo finance page showing stock information for those symbols. There can be no space between stocks: and the URL Source: http://www.google.com/help/operators.html

111. stocks:Symbol1 Symbol2 … stocks:dis

112. define: If you begin a query with define: Google will display definitions for the word or phrase that follows, if definitions are available. You don’t need quotes around your phrases. Source: http://www.google.com/help/features.html#definitions

113. define:term define:pirate define:barbary coast

114. Google Calculator Simply key in what you'd like Google to compute (like 2+2 ) and then hit enter. Google’s Calculator can solve math problems involving basic arithmetic, more complicated math, units of measure and conversions, and physical constants. Source: http://www.google.com/help/features.html#calculator

115. 3+44 56*78 1.21 GW / 88 mph 100 miles in kilometers sine(30 degrees) G*(6e24 kg)/(4000 miles)^2 0x7d3 in roman numerals

116. weather Using weather presents the three to four day weather forecast for a particular US city. You don’t need a colon in weather. Use weather by itself for local weather or add the location for other cities. Source: http://www.google.com/help/operators.html

117. weather city weather city state weather zip code weather los angeles weather pasadena, ca weather 91101

118. movie Using movie presents movie show times for your location. You don’t need a colon in movie. Use movie by itself for local weather or add the location for other cities. Click the Showtimes link for details. Source: http://www.google.com/help/operators.html

119. movie city and state [or zip] movie keyword[s] movie pasadena,ca movie pirates

120. Advanced Operators Query modifiers filetype: intitle: inurl: site: ~ AROUND(n) Alternative query types cache: link: related: info: Other information needs stocks: define: Google Calculator weather movie

121. The Last Part: Google Resources Where to get more information

122. http://www.google.com/support Google Help Central Free guides and FAQs that tell you about Web searching in general and Google’s features in specific.

123. Google Announcements For more information about what’s new and what’s next at Google, I recommend visiting the following sites: –Google Labs http://labs.google.com/ –Google Blog http://googleblog.blogspot.com/ –Google Blogoscoped http://blogoscoped.com/ –Google Operating System http://googlesystem.blogspot.com/

124. Part 3: digital libraries Source: Tefko Saracevic, Principles of searching (http://comminfo.rutgers.edu/~tefko/Courses/e530/index.htm/) 123

125. 124 definition digital libraries are viewed from several perspectives –technical: “Digital library is a managed collection of information, with associated services, where information is stored in digital format and accessible over a network.” (Arms, 2000) –institutional: “Digital libraries are organizations that provide the resources, including the specialized staff, to select, structure, offer intellectual access to, interpret, distribute, preserve the integrity of, and ensure the persistence over time of collections of digital works so that they are readily and economically available for use by a defined community or set of communities.” (Waters, 1998)

126. 125 a bit of context short but volatile history –research & development took of by start/mid 1990’s –in the next decade phenomenal growth worldwide –large investment in research & building number of communities involved –computer science, primarily in research –many subjects: digital libraries in their domain –library & information science: operations, studies of users, use, usability number of types emerged

127. 126 libraries & digital resources libraries (particularly research, academic & special) directed massive funding toward such resources –electronic journals –databases –catalogs –digitization of parts of collection thus becoming in effect digital libraries – or more accurately hybrid libraries –with graphic and digital versions or types of resources

128. 127 emphasis here on large academic or research digital libraries that also are related to searching –provide search capabilities or access to search engines –provide electronic journals that provide full text of articles after a search such libraries have become also search portals of sort, essential for their users –in education, research & related activities

129. 128 sample New York Public Library Digital “NYPL Digital is your gateway to The New York Public Library’s rare and unique collections in digitized form.” Includes access to searchable databases U California Berkeley Digital Library SUNsite “builds digital collections and services while providing information and support to digital library developers worldwide. The British Library “The world’s knowledge.” Includes “Services fro library and information Professionals.”

130. 129 sample … National Library of New Zealand includes searching of their digital collections Research Library Group “ RLG is a not-for-profit organization of over 150 research libraries, archives, museums, and other cultural memory institutions.” Includes links to a number of searchable collections Public Library of Science “PLoS is a nonprofit organization of scientists and physicians committed to making the world's scientific and medical literature a public resource.” Publishes open access journals

131. 130 some critical issues for searching no way yet to do federated searching in digital libraries –to search several indexes at the same time –each source has to be searched separately most have very different search features, capabilities finding items in indexes does not mean that always able to get full text thus, searching time-consuming, chaotic

132. 131 where to find out? information about digital libraries LibWebLibWeb U California, Berkeley “lists currently over 8000 pages from libraries in 146 countries” Digital Library Federation “a consortium of libraries and related agencies that are pioneering the use of electronic-information technologies to extend their collections and services” D-Lib Magazine “a solely electronic publication with a primary focus on digital library research and development, including but not limited to new technologies, applications, and contextual social and economic issues”

133. 132 where? … Ariadne Ariadne (UK) “to report on information service developments and information networking issues worldwide, keeping the busy practitioner abreast of current digital library initiatives”

134. 133 University of Novi Sad libraries – digital components Work in progress in developing digital access Some resources –Internal (mostly metadata search, no systematic access to primary digital content available yet) Central University Library Repository of PHD theses Faculties/Department libraries –Faculty of Sciences – Department of Mathematics and InformaticsFaculty of Sciences – Department of Mathematics and Informatics –Faculty of Technical SciencesFaculty of Technical Sciences –……. –External (simple search providing access to international and domestic scientific journals) KOBSON provided by National Library of SerbiaKOBSON Situation affecting teaching, learning, research by the whole University

135. Part 4: Communication and Computer networks

136. Learning Objectives Identify the basic components, functions, and types of telecommunications networks used in business. Explain the functions of major types of telecommunications network hardware, software, media, and services.

137. Telecommunications Networks Communication is one of the most important of all human needs. A business is a complex organization that relies on communication among its employees to organize its internal activities and communicate with its customers and suppliers to generate and sell its products and services. Communication becomes even more important in a global environment. Telecommunications is the communication of information by electronic means. It requires the following five steps: -Sender initiates message communication -Device puts sender’s message onto a telecommunications medium. -Telecommunications medium transfers message to receiver’s location -Device takes message off the communication medium -Recipient receives the message

138. Telecommunications capacity The capacity for information flow over a telecommunications channel is called bandwidth. It is usually measured in bits/second. Face-to-face bandwidth is simply limited by how fast we can talk. Communication among computer devices usually occurs with much greater bandwidth.

139. Types of telecommunications networks We distinguish among different network types based on the dimensions of communication: –organizational context, and –distance. On the organizational context dimension networks are called –intranets if they serve a company’s employees, –extranets if they serve employees and partner organizations.

140. Types of telecommunications networks On the distance dimension –Wide area networks (WAN) is a broad-band computer network that spans a large geographical area (they serve greater distance). Used by multinational companies. WANs transmit and receive information across cities and countries. Some WANs are commercial, regulated networks while others are privately owned (Ex: AT&T or Sprint). Some others are public in terms of their management, resources and access. One such public WAN is the Internet.

141. Types of telecommunications networks On the distance dimension –Local Area Networks (LANs)- A LAN connects two or more communicating devices within a short distance (One building or several buildings in close proximity). It allows all computer users to connect with each other to share information and devices, such as printers. In an office a LAN can give users fast and efficient access to a common collection of information while also allowing the office to pool resources, such as printers. –Metropolitan Area Networks (MANs)- They serve a large city.

142. Types of telecommunications networks On the distance dimension –Virtual Private Networks (VPN): VPN is a private wide- area network that connects an organization's LAN and users to another through a public network, usually the Internet. A VPN provides long-distance connections virtually free of direct charges. A VPN handles the security and it uses the Internet as its main network, but relies on firewalls and other security features of its Internet and Intranet connections. VNP is a means for allowing access to a private network’s e- mail, shared files or intranet via an Internet connection.

143. Essential components of Telecommunications Networks Network nodes –Computers –Terminals or any input/output devices Telecommunications network software Telecommunications processors (devices) Telecommunications channels/media

144. Computers Telecommunications networks interconnect computers of all sizes and types. They include (by size): 1.Host computers (mainframes) 2.Front-end Processors (minicomputers) 3.Microcomputers Computers connected to the network are classified (by type) into two broad categories: 1.Servers 2.Clients

145. Terminals Terminals are any input/output devices that use telecommunications networks to transmit or receive data. They include: 1.Telephones 2.Personal computers 3.Network computers 4.Office equipment 5.Video terminals

146. Telecommunications network software Consists of programs that control telecommunications activities and manage the functions of telecommunications networks. They include network operating systems, Web browsers, and programs. –Ex: Many operating systems such as Windows 2000/Server provide a number of key network services. Allows network managers to add or delete users and to specify their permission to access to files, devices and services. –Ex: HP’s OpenView is a network management software. A network analyst can perform many network management functions.

147. Network Topologies Arrangement of computers, transmission media, and other network components Physical topology –Layout of “real” components of network Logical topology –Virtual connections among network nodes Protocol is set of rules for exchanging communication

148. Bus Topology All computers are connected in sequence on a single cable Used in peer-to-peer networks

149. Bus Topology Comparison Advantages It uses a minimal amount of cable Installation is easy, reliable, and inexpensive Disadvantages Breaks in the cable can disable the network Large numbers of users will greatly decrease performance because of high volume of data traffic

150. Network Topologies Arrangement of computers, transmission media, and other network components Physical topology –Layout of “real” components of network Logical topology –Virtual connections among network nodes Protocol is set of rules for exchanging communication

151. Bus Topology All computers are connected in sequence on a single cable Used in peer-to-peer networks

152. Bus Topology Comparison Advantages It uses a minimal amount of cable Installation is easy, reliable, and inexpensive Disadvantages Breaks in the cable can disable the network Large numbers of users will greatly decrease performance because of high volume of data traffic

153. Ring Topology Nodes are laid out in a ring A token (data packet) flows in one direction from device to device Recent versions have data transfer rates of up to 100 Mbps

154. Ring Topology Comparison Advantages Allocates access to the network fairly Performance remains acceptable even with large numbers of users Disadvantages Adding or removing nodes disables network Failure of one computer can bring down the entire network Problems in the ring can sometimes be difficult to find

155. Star Topology Most widely deployed client/server network layout Nodes connect to a central communications device (switch) Switch receives a signal and retransmits it A node accepts only signals addressed to it

156. Star Topology Comparison Advantages Failure of one computer does not affect other computers on the network Centralized design simplifies troubleshooting and repairs Adding computers or groups of computers is easy. Performance remains acceptable even with large numbers of users Disadvantages Requires more cable (and possibly higher installation costs) than a bus or ring topology The switch is a single point of failure If it fails, all computers connected to that switch are affected

157. Client/Server Networks Client/server networks contain servers as well as client computers Server is computer that stores and shares resources on a network Client is computer that requests those resources Servers respond to requests from large number of clients

158. Servers Workhorses of the client/server network Interface with many network users Assist with a variety of task Small networks have just one server Large networks use dedicated servers –Fulfill one specific functions –Reduce load on main server

159. Print Servers Manage client-requested printing jobs for all printers on a network Helps client computers complete more productive work Frees the CPU to do other jobs Organize print jobs into orderly sequence Can prioritize print jobs

160. Application Servers Act as a repository for application software Avoids installing software on thousands of personal computers Eases task of installation and upgrading Application is installed and upgraded only on the application server

161. Database Servers Provides client computers with access to database information Many people can access a database at the same time through the network

162. E-Mail Servers Volume of e-mail on large network could overwhelm a server Sole function of an e-mail server is to process and deliver e-mail –Incoming –Outgoing

163. Communications Servers Handles all communications between the network and other networks, including managing Internet connectivity Often the only device on the network directly connected to the Internet E-mail servers, Web servers, and other devices route traffic through the communications server

164. Web Servers & Cloud Servers Web servers –Host a Web site that will be available on the Internet –Many colleges and businesses use a third-party Web hosting company Cloud servers –Servers that are maintained by hosting companies, and are connected to networks via the Internet

165. Telecommunications processors Support data transmission and reception between terminals and computers. They include modems, switches, routers. A modem provides an interface between a computer (or network) and the phone line, cable line (or cellular connection). Switches control traffic within a single local network Routers interconnect different local networks

166. Network Adapters Devices that perform tasks to enable computers to communicate on a network Network interface cards (NICs) are installed inside computers and peripherals Network adapters perform three critical functions: –Generate network transmission signals –Create data packets –Act as information gatekeepers

167. Network Navigation Devices Data flows through network in packets Each network adapter has physical address called a media access control (MAC) address –Six two-position characters (such as 01:40:87:44:79:A5) First three sets specify manufacturer Second set makes up unique address

168. Switches and Bridges Used to send data on a specific route through network Switch makes decisions based on MAC address as to where data is sent Bridge is a device used to send data between different collision domains

169. Routers Router is designed to send information between two networks Must look at higher-level network addresses such as IP addresses

170. Telecommunications channels Telecommunications channels connect the message source with the message receiver. A channel can use different kinds of telecommunications transmission media. Telecommunications media physically link the devices in a network. They include twisted wire, coaxial cable, fiber optics, terrestrial microwave, satellite and other wireless transmission.

171. Types of Signals: Analog and Digital Information travels through a telecommunications system in the form of electromagnetic signals. Signals are represented in two ways: analog and digital signals. An analog signal is a continuous waveform that passes through a communications medium; used for voice communications. A digital signal is a discrete rather than continuous, waveform. Most computers communicate with digital signals. All digital signals must be translated into analog signals before they can be transmitted in an analog system. The device that performs this translation is called a modem (Modem is an abbreviation for MOdulation/DEModulation). A modem translates a computer’s digital signals into analog form for transmission over ordinary telephone lines, or it translates analog signals back into digital form for reception by a computer.

172. Transmission Media Network engineers can use different type of media Transmission media comprise the physical system that data takes to flow between devices on a network –Wired connections –Wireless connections

173. Wired Transmission Media Popular in business networks Generally provide higher throughput than wireless connections Types of wired connections –Twisted-pair cable –Coaxial cable –Fiber-optic cable

174. Choosing a Cable Maximum run length Bandwidth Bend radius (flexibility) Cable and installation costs Susceptibility to interference Signal transmission methods

175. Twisted-Pair Cable Pairs of copper wire twisted around each other Twists make the wires less susceptible to outside interference Two types Shielded twisted- pair (STP) Unshielded twisted- pair (UTP

176. Coaxial Cable Four main components –Copper core –Nonconductive insulating material –Braided metal shielding –Plastic cover

177. Fiber-Optic Cable Components include –Glass or plastic fibers –Cladding –Outer jacket Transmission in only one direction Signals converted to light pulses Immune to interference

178. Wireless Media Options Usually add-ons that extend access to wired network Often provided to give employees a wider working area Corporate networks are often a combination of wired and wireless media

179. Wireless Media Wireless transmission sends signals through air or space without being tied to a physical line. Common technologies for wireless data transmission include: 1.Microwave: Used for long-distance transmission. uses the atmosphere as the medium through which to transmit signals. Can carry high-volume data. Expensive. Requires no cabling.

180. Wireless Media 2.Communication satellites: The transmission of data using orbiting satellites. Cost effective for transmitting large quantities of data over very long distances. Typically used for communications in large, geographically dispersed organizations that would be difficult to tie together through cabling media. Very expensive. Signals weaken over long distances. It is useful for only 7-10 years.

181. Wireless Media: Wireless Media: ORBITING SATELLITES UPLINK MICROWAVE TRANSMISSION DOWNLINK

182.  3. Cellular phones: Work by using radio waves to communicate with radio antennas placed within adjacent geographic area called cells. It transmits voice or data. It is for mobile voice and data communications.  4. Pagers: An wireless transmission technology in which the pager beeps when the user receives a message. Used (long time ago) to transmit short alphanumeric messages. Wireless Media

183. Comparing Transmission Media Cable Characteristics Twisted Pair (Cat 6) Twisted Pair (Cat 6a) Fiber-Optic Maximum run length 328 feet (100 m) Up to 62 miles (100 km) BandwidthUp to 1 GbpsUp to 10 Gbps10 to 40 Gbps Bend radius (flexibility) No limit 30 degrees/foot Cable costExtremely lowLowHigh Installation costExtremely low Most expensive because of installation training required Susceptibility to interference High None (not susceptible to EMI or RFI)

184. Network Security for Client/Server Networks Offer higher level of security than peer-to-peer networks Security can be centrally administered by network administrators Frees individual users of responsibility of maintaining own data security

185. Sources of Security Threats Human errors and mistakes –Incorrect posting Malicious human activity –Perpetrated by current/former employees or third parties Natural events and disasters –Hurricanes and other acts of nature

186. Network Security for Client/Server Networks Offer higher level of security that can be centrally administered Threats can be classified into three groups: –Human errors and mistakes –Malicious human activity –Natural events and disasters

187. Authentication Process where users prove they have authorization to use computer network –Provide a user ID and password –Biometric devices –Possessed objects Identification badges Magnetic key cards Smart keys

188. Access Privileges When account is set up, certain access privileges are granted to indicate which systems you are allowed to use On a college network you might: –Have ability to access the Internet –View grades and transcripts Would not have ability to change grades

189. Physical Protection Measures Restricting physical access to servers and other equipment is critical Devices are secured in ceilings, walls, or closets Only authorized personnel have access

190. Firewalls Firewalls for business networks work on same principles as personal firewall Work as packet screeners with external screening router examining incoming data packets Unauthorized or suspect packets are discarded

191. Network Firewall Layout

192. Telecommunications Technology Organizations use diverse network technologies that may or may not be compatible with the technologies of other organizations. So many different networks are interconnected nowadays, they must have a common language or protocol to communicate. The protocol of the Internet is called Transmission Control Protocol/Internet Protocol (TCP/IP). Two computers using TCP/IP would be able to communicate even if they were based on different hardware and software platforms.

193. Part 5: Internet and how it works Sources:

194. Topics What is Internet Management of the Internet Internet networking Data transmission and protocols Internet identity HTTP, HTML, and other Web building blocks Communications over the Internet

195. What is Internet Internet is the most influential development over the past two decades. It is derived from the concept of Internetworking, linking hundreds of individual networks all over the world. Frequently referred to as the “Net”. The Internet is a global network of computer networks linked together so that its users can share data resources.  The Internet provides instant and local access to an amazing number of organizations, individuals, and information resources.  No one owns the Internet and it has no formal management organizations. Originally the Internet was an initiative sponsored by the Department of Defense to link its labs with American universities. The Internet does not have a central computer system. The Internet does not have a governing body.

196. Management of the Internet No single entity is in charge of Internet Local networks are owned by: –Individuals –Universities –Government agencies –Private companies Managed by nonprofit organizations and user groups

197. Internet Networking Much information is now stored out in the “cloud” You can summon up information stored on servers around the world –Enter a URL in your browser –Enter a search topic in a search engine Series of communication transactions enable Internet to function as global network

198. Connecting to the Internet

199. How can we connect to the Internet? Even today individuals cannot connect directly to the Net. Anyone with a computer, a modem and a willingness to pay a small monthly usage fee can access Internet through an Internet Service Provider (ISP). ISPs will provide you a username, password and access phone number. ISP is a commercial organization that offers Internet access (AT&T) or online service (MSN, AOL).

200. Connecting to the Internet Internet backbone –Collection of large national and international networks –T lines: Initially used for backbone ISP connections Carried digital data over twisted-pair wires –Optical carrier line (OC): Today’s most common backbone ISP connection High-speed, fiber-optic lines designed to provide high throughput

201. OC line speeds

202. Internet connection There are a number of ways that people can connect to the Internet. In addition to traditional connections through plain old telephones and modems, there are a number of high-speed alternatives. 1.Plain old telephone service: using phone line to connect the Internet. 2.Integrated Services Digital Network (ISDN): using existing twisted-pair phone wires to provide high speed service. 3.Digital Subscriber Line (DSL): provides high speed over regular copper telephone lines. 4.Cable Modems (TV lines): In some areas the company that provides cable TV service also provides Internet service. 5.Satellite connections: In many regions of the world people can now access the Internet via Satellite. 6.Cellular phones: There are Internet-enabled cellular phones from Sprint and others, and small palm-top computers from Palm and others, that give you Internet access nearly anywhere.

203. Network Model of the Internet Internet communications follow the client/server network model of network communications –Clients request services –Servers provide services to clients

204. Types of Servers Web servers –Host Web pages Commerce servers –Enable the purchase of goods and services over the Web File servers –Provide remote storage space for files that users can download

205. Peer-to-Peer File Sharing

206. Data Transmission and Protocols Computer protocol is a set of rules for exchanging electronic information Internet protocols had to be an open system design Networks can communicate even if they have different topologies, transmission media, or operating systems

207. Circuit Switching Technology available in 1960s Dedicated connection is formed between two points Remains active for duration of transmission Used since early days of the telephone communications Inefficient for computers

208. Packet Switching Makes computer communication efficient Data is broken into small units (packets) Packets are sent over various routes to their destination Packets are reassembled by the receiving computer

209. Packet Contents Contents vary depending on protocol At a minimum, all packets must contain: 1.Address to which packet is being sent 2.Address from where packet originates 3.Reassembling instructions, if original data was split 4.Data that is being transferred

210. Packet Switching

211. TCP/IP Main suite of protocols used on Internet Transmission Control Protocol (TCP) –Prepares data for transmission –Provides error checking –Enables resending lost data Internet Protocol (IP) –Responsible for sending information from one computer to another

212. Internet Identity Each computer, server, or device connected to the Internet is required to have unique identification number Numeric IP addresses were given more “human” word-based addressed Domain names were born

213. IP Address Unique number that identifies each device connected to the Internet Typical IP address – 197.24.72.157 Static addressing –IP Address never changes Dynamic addressing –Temporary address from available pool

214. Domain Names Domain name takes place of an IP address Easier to remember Organized by level –Top-level domain (TLD) Portion of the domain name that follows the dot Includes.com,.org,.gov,.edu, and.net –Second-level domain Unique name within a top-level domain Yahoo.com, Whitehouse.gov, Unesco.org

215. Internet Agencies

216. Domain Name System Servers Internet servers that translate domain names into IP addresses ISPs go first to a default DNS to resolve a name Name queries work up the hierarchy to the root DNS servers if required

217. DNS Servers in Action

218. HTTP, HTML, and Other Web Building Blocks World Wide Web is grouping of protocols and software that resides on Internet Web uses special languages and protocols to facilitate communication between computers

219. Web Browser Security Protocols HyperText Transfer Protocol (HTTP) –For transfer of hypertext documents HyperText Transfer Protocol Secure (HTTPS ) –Combination of HTTP and network security protocol Transport Layer Security (TLS) and Secure Sockets Layer (SSL) –Protect data integrity of data and security of transmissions over the Internet

220. HTML/XHTML Web page is a text document formatted using Web languages –HyperText Markup Language (HTML) –eXtensible HyperText Markup Language (XHTML) Sets of rules for marking up blocks of text so browser know how to display them

221. HTML

222. XML eXtensible Markup Language (XML) –Designed for exchanging information Can be used to create your own markup language Used in e-commerce transactions Custom packages for specific communities –MathML, Wireless Markup Language (WML)

223. Common Gateway Interface Provides methodology so browsers can request that a program file be executed CGI files are often called CGI scripts Adds Web page interaction –Adding names to guest books/mailing lists –Completing forms 222

224. CGI Example

225. Dynamic HTML A combination of technologies used to create interactive Web sites –HTML/XHTML –Cascading style sheets –JavaScript

226. AJAX and JavaScript Asynchronous JavaScript and XML (AJAX) –Newer group of technologies that facilitates creation of Web applications –Does not actually require JavaScript or XML JavaScript –Most commonly used scripting language for creating DHTML effects

227. Cascading Style Sheets List of statements that defines in a single location how to display HTML/XHTML elements Enable a Web developer to define a style for each HTML/XHTML element and apply it to multiple elements on many Web pages Allows for creation of formatting templates

228. Client Side Applications Programs that run on client computer with no interaction with a Web server Two main types: –Embedding programming language code directly within HTML or XHTML code of a Web page –Applet is a small application that resides on a server and when requested, compiled version is downloaded to client computer

229. Client Side App Example

230. Communications over the Internet Communications revolution began to explode in the mid 1990s Internet e-mail –Growing exponentially each month –97 percent is spam Texting and instant messaging Voice over Internet protocol

231. E-Mail Simple Mail Transfer Protocol (SMTP) is used for sending e-mail along Internet Popular client-based e-mail software: –Microsoft Outlook –Mozilla Thunderbird Web-based e-mail software –Gmail –Yahoo! –Hotmail

232. Sending Email

233. E-Mail (cont.) Multipurpose Internet Mail Extensions (MIME) simplifies attachments to e-mail messages Handles encoding and decoding

234. E-Mail Security: Encryption and Specialized Software Encryption is process of coding e-mail so only person with key to code can read the message Two basic types of encryption –Private-key encryption Only two parties involved have code –Public-key encryption Two keys (key pair) are created One key used for coding, other for decoding

235. Encryption Example

236. Instant Messaging Act of communicating with one or more people in real time Top IM programs –AOL Instant Messenger (AIM) –GoogleTalk –Yahoo! Messenger –Jabber –Windows Live Messenger

237. How Instant Messaging Works

238. Voice over Internet Protocol (VoIP) Turns standard Internet connection into way to make free long-distance phone calls Collection of communication and transmission protocols Uses TCT/IP protocols to route phone calls across the Internet

239. World Wide Web Web is the Internet systems for hypertext linking, allowing users to move from one Internet site to another. It is a system with universally accepted standards for storing, retrieving, formatting and displaying information. Web pages are online documents that feature clickable hypertext links that transport you to documents, graphics or other Web pages. Internet browser softwares such as Netscape Navigator or Internet Explorer enable end users to surf the Web. Anyone using a Web browser can access any of millions of Websites. To access a Web site the user must specify Uniform Resource Locator (URL) which is the address of a specific resource on the Internet. The URL for our university is http://www.uns.ac.rs.http://www.uns.ac.rs http stands for hypertext transport protocol, which is the communications standard to transfer pages on the Web. Web sites are created by Web masters.

240. What are people doing on the Internet? E-mail: You can use e-mail to communicate with your friends, to exchange messages. Surf: You can browse websites and resources for information, entertainment and e-commerce. Chatting: Allows two or more people who are simultaneously connected to the Internet to hold live, interactive conversations. (Ex: Yahoo! Messenger)

241. What are the people doing on the Internet? Discussion: Participating in discussions on thousands of topics. Download: Allows to transfer data files, software, articles, picture, music, video to your computer system. Buy and sell: Buying and selling via e-commerce retailers, wholesalers (Ex: E-bay). Search for information: Several companies have created directories of Web sites and their addresses, providing search tools for finding information. Another tools, called search engines can find Web sites. (Ex: Yahoo!, Google, Alta Vista). Play games, watch TV, conduct free phone calls, listen to radio, etc.

242. The business value of the Internet  E-commerce is the major business use of the Internet.  For marketing, sales and customer relationship management applications, applications in engineering and human resources.  Enterprise communication and collaboration  Forming new business partnerships  Providing customer and vendor support Business use of the Internet

243. INTRANET An Intranet is a private and internal network using Web technologies inside an organization. It can be considered a private internal Web, which limits viewing access to authorized users within the organization. It enables employees to communicate, share information and work together on common projects regardless of their physical location. Employees access information on the Intranet through a Web browser. This information cannot be viewed by users outside the organization. Thus it is separated from the visible, publicly accessible Web. It is protected by security measures such as passwords, firewalls.

244. INTRANET Intranets require no special hardware. Intranet software technologies is the same as that of the Web. The Web browsers and Web server software for intranets are the same as those on the Web. Ex: Hewlett Packard (HP) uses an intranet for many human resource functions. The company’s 88,000 employees in 150 countries can access HP’s intranet to fill out forms about beneficiaries, address changes, tax withholdings, etc. Ex: Boeing offers over 200,000 employees training via the Center of Leadership and Training (CLT) intranet sites. It opens up the courses and training opportunities for employees worldwide. By using the CLT intranet, employees can choose from a wide range of course offerings.

245. EXTRANET Extranets are private intranets extended to authorized users outside the company. It is accessible to authorized outsiders. Firms use such networks to coordinate their activities with business partners, suppliers, customers for making purchases, collaborating on design and other interorganizational work. An extranet connects the intranets of two or more business partners. Extranets are useful for linking organizations with suppliers, customers or business partners. Extranets make customer and supplier access of intranet resources a lot easier and faster than previous business methods.

246. FOCUSTYPE OF INFORMATION USERSACCESS The InternetExternal communications General publicAny user with an Internet connection/public and not restricted The IntranetInternalEmployeesAuthorized employees/private and restriction The ExtranetExternalBusiness partners, customers, suppliers Authorized business partners/private and restriction Characteristics of The Internet, Intranet, and Extranet