1 Finding information through the Internet and the WWW: a tutorial Vrije Universiteit Brussel Information and Library Science,

1 Finding information through the Internet and the WWW: a tutorial Paul.Nieuwenhuysen@vub.ac.be Vrije Universiteit Brussel Information and Library Science, University of Antwerp Belgium Presented at ICDL 2004, the International Conference on Digital Libraries in New Delhi, India, February 2004

2 The slides are available from http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/ (note: BIBLIO and not biblio)

3 Fundamental difficulties in information retrieval, and how to take these into account. Thesaurus systems for better information retrieval. - contents - summary - structure - overview of this tutorial

4 Online access information sources and services (1) »types of information sources »a systematic overview of information sources and services that are accessible through the Internet: »dictionaries and encyclopedias »Internet subject directories for browsing »Internet indexes for text searching - contents - summary - structure - overview of this tutorial

5 Online access information sources and services (2) »making better search queries with general thesaurus systems that are available free of charge »meta-search systems »the invisible web and how to exploit its contents, even though it is hidden away from text search systems »finding images/pictures - contents - summary - structure - overview of this tutorial

6 Online access information sources and services (3) »using image retrieval systems on the WWW to find relevant texts »finding books »finding journal articles »fee-based databases »using fee-based electronic journals »open access electronic journals - contents - summary - structure - overview of this tutorial

7 Online access information sources and services (4) »analyzing and exploiting citations (hyperlinks) on WWW pages to particular other known WWW pages. »conclusion on Internet information retrieval - contents - summary - structure - overview of this tutorial

8 How to evaluate information retrieval systems and queries? How to evaluate the quality of information sources? - contents - summary - structure - overview of this tutorial

9 Is there a subject about which YOU personally would like to learn more?

10 -Interruptions -Questions -Remarks -Discussions are welcome

11 Databases and computerized information retrieval Introduction ****

12 Types of databases: examples Examples: The databases that form the basis for »catalogues of books or other types of documents »computerized bibliographies »address directories »a full text newspaper, newsletter, magazine, journal + collections of these »WWW and Internet search engines »intranet search engines »... ****

13 Information retrieval: the terminology Several words are used with similar or related meanings: »database / databank / corpus / collection / catalog / site / archive / file / web /... »contents of a database / records / documents / items / (web) pages /... »search / query / filter /... »thesaurus / controlled vocabulary / dictionary / lexicon / term bank / ontology /... »results / selection / retrieved documents / retrieved items /... ***-

14 Comparison Information retrieval: the basic processes in search systems Information problem Representation QueryIndexed documents Representation Retrieved, sorted documents Text documents Evaluation and feedback ****

15 Information retrieval systems: many components make up a system Any retrieval system is built up of many more or less independent components. These components can be modified to increase the quality of the results more or less independently. ***-

16 Information retrieval systems: important components ***- the information content system to describe formal aspects of information items system to describe the subjects of information items concrete descriptions of information items = application of the used information description systems information storage and retrieval computer program(s) computer system used for retrieval type of medium or information carrier used for distribution

17 What determines the results of a search in a retrieval system? the information retrieval system ( = contents + system) the user of the retrieval system and the search strategy applied to the system ***- Result of a search

18 Layered structure of a database Database (File) Records Fields Characters + in many systems: relations / links between records ***-

19 A simple database model: all records together form a database The salami model = sliced bread model »the salami or the bread is a “database” »each slice of salami or bread is a “database record” »there are no relations between slices / records »the retrieval system tries to offer the appropriate slices / records to the user ***-

20 Characteristics / definition of structured text-information The text information is structured. (files, records, fields, sub-fields, links/relations among records,...) The length of records and fields can be “long”. Some fields are multi-valued = they occur more than once = repeated or repeatable fields **--

21 Structure of a bibliographic file Record No. 1 Title Author 1: name + first name Author 2:... Source Descriptor 1 Descriptor 2... Record No. 2 Sub- fields Repeated fields **--

22 Databases and computerized information retrieval Text retrieval and language ****

23 Text retrieval and language: an overview Problems related to language / terminology occur 1. even when the same language is used in searching and in the searched databases 2. in the case of “multi-linguality”: “cross-language information retrieval” that is when more than 1 language is used »in the search terms »in the contents of the searched database(s) and/or in the subject descriptors of the searched database(s) ***- 

24 Text retrieval and language: enhancing retrieval Retrieval can be enhanced by coping with the problems caused by the use of natural language. Contributions to this enhancement of retrieval can be made by »the database producer »the computerized retrieval system »the searcher/user (The distinction between these is not very sharp and clear in all cases.) ***-

25 Text retrieval and language: a word is not a concept (a) Problem: A word or phrase or term is not the same as a concept or subject or topic. **** Word Concept 

26 Text retrieval and language: a word is not a concept (a’) So, to ‘cover’ a concept in a search, to increase the recall of a search, the user of a retrieval system should consider an expansion of the query; that is: the user should also include other words in the query to ‘cover’ the concept **** 

27 Text retrieval and language: a word is not a concept (a’’) »synonyms! (such as scientific names besides common names) »narrower terms, more specific terms (such as particular brand names); including terms with prefixes (for instance: not only viruses, but also retroviruses, rotaviruses...) »spelling variations (such as UK English versus US English); possible variations after transliteration **** 

28 Text retrieval and language: a word is not a concept (a’’’) »singular or plural forms of a noun (when this is used as a search term) »(relevant) related terms »various forms of a verb (when this is used in the query) »broader terms (perhaps) **** 

?? Question ?? Which problems in text retrieval are illustrated by the following sentences? **** 29 

30 Time flies like an arrow. Fruit flies like a banana. ? ****Examples

31 Time flies like an arrow. Fruit flies like a banana. ****Examples

32 Time flies like an arrow. Fruit flies like a banana. OK! ****Examples

33 Text retrieval and language: ambiguity of meaning (a) Problem: A word or phrase can have more than 1 meaning. Ambiguity of the meaning of a word is a problem for retrieval. This decreases the precision of many searches. The meaning can depend on the context. The meaning may depend on the region where the term is used. **** 

34 Text retrieval and language: ambiguity of meaning (a’) Example of a word: »Pascal the philosopher »Pascal the computer language ****Example 

35 Text retrieval and language: ambiguity of meaning (a’’’) Problem: Ambiguity of meaning may be the cause of low precision. **** Word Concept 

36 Text retrieval and language: relation with recall and precision Recapitulating the two problems discussed, we can say that Expansion of the query allows to increase the recall. Disambiguation of the query allows to increase the precision. **-- 

37 Text retrieval and language: phrases composed of words (a) Problem: Most retrieval systems can search for words, but they do not directly recognize or ‘know’ phrases / terms composed of more than 1 word. ***- 

38 Text retrieval and language: phrases composed of words (b) Methods to solve the problem, provided by the computerized retrieval system: »the user can and should indicate explicitly that a few words should be considered together by the retrieval system as forming a phrase/term (for instance in many Internet search engines by putting the phrase in quotes like “three word phrase”) ***-

39 Text retrieval and language: phrases composed of words (b’) »better: the retrieval system automatically recognizes a phrase/term relying on a term bank that has been created in advance; examples: the Internet search engines AltaVista and Scirus work in this way ***-

40 Natural language processing of the documents AND of the query Comparison and matching of both Enhanced text retrieval using natural language processing Information problem Representation QueryIndexed documents Representation Retrieved, sorted documents Text documents Evaluation and feedback **--

41 Text retrieval and language: conclusions The use of terms and language to retrieve information from databases/collections/corpora causes many problems. These problems are not recognized or underestimated by many users of search/retrieval systems = The power of retrieval systems is overestimated by many users. Much research and development is still needed to enhance text retrieval. ***-

42 Databases and computerized information retrieval Hints on how to use information sources ****

43 Hints on how to use information sources: overview (Part 1) Know the purpose and motivation for each search. Do not be lazy: search on your own, before bothering experts with requests for advice. Plan your search in advance. Choose the best source(s) for each search. Use the available tools for subject searching well. Try to cope with the language problems; avoid spelling errors in your search query; use spelling variations in your search query ****

44 Hints on how to use information sources: overview (Part 2) Match your search strategy with the type of source. Work cost-effectively. Use special care when searching for names. Be specific; avoid broad searches. Work iteratively. Keep a record of your work. Be critical: not all information is correct or useful. Do not only focus on a single source. ****

45 Hints on how to use information sources: overview (Part 3) Consider citation indexes besides subject-oriented databases, as useful secondary information sources. Stop searching when “enough is enough” Give up if necessary... (Not all questions have an answer.)... ****

46 Hints on how to use information sources: overview (Part 4) In computer-based retrieval systems, consider applying »truncation of search terms (*, ?...) »combine search terms, using —Boolean operators (OR; AND / +; NOT / AND NOT / -) —proximity operators (for instance “NEAR”,...) —phrase searching (“word1 word2”) »searching limited to a field (for instance URL, title…) ****

47 Hints on how to use information sources: subject searching When you search for information on a particular topic/subject: investigate if the database producer offers »a subject classification scheme and/or »a controlled/approved/accepted subject terms, and/or »a subject thesaurus Exploit these, if they are available. In most cases you should find and use synonyms and narrower terms Use broader and /or related terms, if appropriate. ****

48 Hints on how to use information sources: Boolean combinations (1) Most text search systems understand the basic Boolean operators: OR = obtain records that contain one or both search terms AND = obtain records that contain both search terms NOT = exclude records that contain a search term ****

49 Hints on how to use information sources: Boolean combinations (2) Most text search systems understand the basic Boolean operators typed in capital characters: OR AND ****

50 Hints on how to use information sources: Boolean combinations (3) In the case of computer-based information sources, use Boolean combinations of search terms when appropriate and when possible. **** term x1 OR term x2 OR term x3 term x1 OR term x2 OR term x3 term y1 OR term y2 OR term y3 term y1 OR term y2 OR term y3 term z1 OR term z2 OR term z3 term z1 OR term z2 OR term z3 AND AND...

51 ?? Question ?? How many (and which) concepts do you see in a search for “general reviews about monitoring seawater pollution that is due to effluents in Tanzania”? ****

52 Hints on how to use information sources: example of a search query Example: Searching for the concept “sea” can or should involve for instance the following words in a Boolean OR combination: baltic OR bay OR bays OR coast OR coastal OR coastline OR coasts OR cove OR coves OR gulf OR mangrove OR mangroves OR marine OR mediterranean OR noordzee OR noordzeekust OR noordzeekusten OR ocean OR oceanic OR oceans OR pacific OR reef OR reefs OR “saline-freshwater interface” OR sea OR seas OR seashore OR seawater OR seawaters OR shore OR shores ***-Example

53 ?? Question ?? What did you learn from the exercise on the formulation of a query? ****

54 Hints on how to use information sources: work iteratively Work iteratively = search, investigate your results, refine your search, search again, and so on; do not try to find everything in 1 step, with 1 search. **** Results Query Searching Feedback

55 Knowledge organisation: classifications, and thesaurus systems Introduction ****

56 To organise knowledge / documents / books / reports / information / data / records / things / items / materials for more efficient storage and retrieval, some related, similar tools / systems / methods /approaches are used. Often but not yet always, this process is assisted by a computer system. Good systems are expanded and updated when the need arises. The organization system applied should ideally be clearly and immediately visible or even searchable on computer, by the user of the materials. Knowledge organisation: introduction ****

57 Various tools / systems / methods / approaches are available: »Classification »Taxonomy »Thesaurus »Ontology »… Knowledge organisation: some tools ***-

58 Knowledge organisation: classifications, and thesaurus systems Classifications ****

59 Universal means here: covering all subjects Not just one but several competing systems exist. Examples »Universal Decimal Classification = UDC used mainly outside U.S.A. »Dewey Decimal Classification = DDC used mainly in U.S.A. »Library of Congress Classification used mainly in U.S.A. »... Classification systems: examples of universal systems ****Examples

60 Knowledge organisation: classifications, and thesaurus systems Thesaurus systems ****

61 Thesaurus: description Thesaurus (contents) = »system to control a vocabulary (= words and phrases + their relations) »the contents of this vocabulary Thesaurus program = program to create, manage, modify and/or search a thesaurus using a computer ****

62 Thesaurus relations Term(s) with broader meaning BT (= Broader Term) RT (= Related Term) UF (= Use(d) For) Other term(s) Term Synonym(s) NT (= Narrower Term) Term(s) with narrower meaning ****

63 Thesaurus applications related to information searching (1) For producers of a database: To find/choose index terms to add these to items in a database, when terms are taken from a controlled vocabulary to increase precision and recall in the searches by users of the database. ***-

64 Thesaurus applications related to information searching (2) For users of a database: When the database to be searched is produced with added descriptors (words and terms) that are taken from a controlled list of approved, selected words and terms, then the searcher can use some printed or computer- based system first, to find more and ‘correct’ suitable words and terms that belong to that controlled list of descriptors; then, the searcher can use these descriptors (and only these words or terms) in a database query. ***-

65 Thesaurus applications related to information searching (3) For users of a database: When the database to be searched is NOT produced with added descriptors (words and terms) that are taken from a controlled list of words and terms, then the searcher can use one or several thesaurus systems first, to find more words and terms and more suitable words and terms; then the searcher can use these found words and terms to formulate a query for that database (to increase recall and precision). ***-

66 Thesaurus systems that cover all subjects General systems Universal systems Covering all subjects Broad and shallow systems Horizontal systems ***-

67 Thesaurus systems that cover all subjects: examples (Part 1) Library of Congress Subject Headings (LCSH) thesaurus system built into word processing software thesaurus system that runs on a pc (independent of Internet) see for instance http://www.wordweb.co.uk/free/http://www.wordweb.co.uk/free/ ***-Examples

68 Thesaurus systems that cover all subjects: examples (Part 2) thesaurus systems that can be used free of charge through the WWW »http://education.yahoo.com/reference/thesaurus/index.htmlhttp://education.yahoo.com/reference/thesaurus/index.html »http://thesaurus.plumbdesign.com/ !http://thesaurus.plumbdesign.com/ ***-Examples

69 General thesaurus system through the WWW: screenshot sea **--Example

70 Thesaurus systems covering all subjects: comments An ideal, complete thesaurus that covers all subjects does not exist. ***-Examples

71 Thesaurus systems focused on a particular subject Focused on a particular subject domain = narrow and deep, vertical systems ***-

72 Thesaurus systems focused on a particular subject: examples ERIC: education, information science,... Psychological Abstracts / PsycInfo Sociological Abstracts / SocioFile INSPEC: physics, electronics, information technology the Aquatic Sciences and Fisheries Information System Medline (the Medical Subject Headings = MeSH) Various thesaurus systems for art and architecture can be found online: http://www.getty.edu/research/tools/vocabulary/ http://www.getty.edu/research/tools/vocabulary/ ***-Examples

73 Knowledge organisation: classifications, and thesaurus systems Classification systems versus thesaurus systems ****

74 Knowledge organization: classifications versus thesauri Classification »Good for placement of documents in a library (because documents on many related subjects can be kept together) »Not well suited for computer searching (too complicated) Thesaurus »Not suited for placement of documents in a library (because documents with related subjects would NOT be kept together) » Well suited for computer searching (relatively simple alphabetic listing of keywords) ****

75 Online access information sources and services Introduction ****

76 Internet based information sources: problems / difficulties (Part 1) Redundancy and overlap: On the one hand, there is too much information on some topics; in other words, the redundancy and overlap are high in many cases. Too few information sources: On the other hand, there are too few information sources on some topics. ****

77 Internet based information sources: problems / difficulties (Part 2) No order is imposed on most sources. Quality checks / quality controls are not performed. Related to this: it is not required to register new information offered. Is the information that you find real, honest, authentic? ****

78 Internet based information sources: problems / difficulties (Part 3) Change is the only constant: Information sources are constantly changing, growing, but sometimes disappearing. ****

79 Internet based information sources: problems / difficulties (Part 4) Scattering: There is no single simple but powerful system to find relevant information through the Internet. In other words: integration / aggregation is still far from perfect. ****

80 Internet based information sources: problems / difficulties (Part 5) Slow: The Internet is in many places and for many applications not yet fast enough. ****

81 Internet based information sources: problems / difficulties (Part 6) In conclusion: Surfing, using the Internet, the WWW, can be a time sink instead of a productive activity. ****

82 Internet based information sources: how many? how much information? More than 10 million WWW sites (in 2003) More than 2000 million (= 2 billion) unique URLs in the total Internet (in 2002) More than 10 terabyte (= 10 000 gigabyte) of text data (in 2001) ****

83 Increasing number of online public access databases Source: Gale Directory of Databases, 1997. ***-

84 Online access information sources and services Types of online access information systems ****

85 Types of online access information systems: “free” versus “fee” **** Public access information sources free of charge Fee-based online information services (NOT free of charge)

86 Online access information sources and services Dictionaries and encyclopedias accessible through the WWW ****

87 Dictionaries and encyclopedias through the WWW: introduction Dictionaries and encyclopedias are the first choice among many types of information sources, »when we do not need detailed information on a common topic »when we want to prepare a more detailed search on an unfamiliar topic, by searching for the right spelling, synonyms, context,… Some dictionaries and encyclopedias are available through the WWW free of charge. ****

88 Dictionaries accessible through Internet and the WWW: example The American Heritage® Dictionary of the English Language »Over 200,000 entries, 70,000 audio word pronunciations, 900 full-page color illustrations »Available free of charge from http://education.yahoo.com/reference/dictionary/ http://education.yahoo.com/reference/dictionary/ ****Example

89 Dictionaries accessible through Internet and the WWW: compilation A compilation/collection of dictionaries can be searched simultaneously and free of charge: http://www.onelook.com/ http://www.onelook.com/ ****Example

90 Encyclopedias accessible through Internet and the WWW: examples Encarta Concise Free Encyclopedia »http://encarta.msn.com/http://encarta.msn.com/ »Available in English and in some other languages ****Example

91 Encyclopedias accessible through Internet and the WWW: examples Encyclopædia Britannica only a small part is available free of charge + links to selected WWW sites »http://www.britannica.com/http://www.britannica.com/ Encyclopædia Britannica Concise »http://education.yahoo.com/reference/encyclopedia/http://education.yahoo.com/reference/encyclopedia/ ****Example

92 Encyclopedias accessible through Internet and the WWW: examples The Canadian Encyclopedia (in English and in French): »http://thecanadianencyclopedia.com/http://thecanadianencyclopedia.com/ ****Example

93 Encyclopedias accessible through Internet and the WWW: overviews A list / overview of encyclopedia on the Internet: http://www.internetoracle.com/encyclop.htm http://www.internetoracle.com/encyclop.htm Other lists of encyclopedia on Internet can be found as a part of more general directories of Internet-based information sources. ****Example

94 Online access information sources and services Internet directories and indexes ****

95 Internet: meta-information about Internet information sources in printed manuals and guides: - it is not always possible to get a copy fast - it costs money to get a copy - they are soon out of date offered on the WWW!: + directly available when we want to use the Internet + many systems are accessible free of charge + most systems are regularly updated (“intelligent agent” software on client PC) ****

96 Internet: subject-oriented meta- information offered via WWW Information about information sources: in the form of »subject guides = texts with references »subject hypertext directories = subject guides »key word indexes, generated automatically, for searching »collections of links or forms to the above »(multi-threaded search systems) ****

97 Internet global subject directories: introduction They are virtual libraries with open shelves, for browsing. They are manually generated, man-made by many people. They can be browsed following a tree structure or a more complicated variation. The most famous of these systems belong to the most popular and most visited sites on the WWW: e.g. Yahoo! ****

98 Internet global subject directories: structure The structure corresponds to a classification that is in most cases specific for the particular overview. In other words: the well-known and classical universal classification systems are not used in most Internet directories. ****

99 Internet global subject directories: pros and cons They cover a small number of selected WWW sites, in comparison with the total number of sites that are accessible.  + The selected, included sites should be better than average. - They are not suitable for deep, detailed, specific searches with a high coverage.

100 Internet global subject directories: why use one? They are suitable mainly for broad searches that can be difficult to formulate in words, but NOT for more specific searches that require combinations of several concepts.

101 Internet global subject directories: Yahoo! A hypertext global subject directory can be found at http://www.yahoo.com/http://www.yahoo.com/ and at many other sites, including http://www.yahoo.co.uk/ http://www.yahoo.co.uk/ Entries are NOT rated. Accessible free of charge. ****Example

102 Internet global subject directories: Yahoo! links in pediatrics Health > Medicine > Pediatrics: International Pediatric Chat - for professionals to share information and education regarding children's health care.International Pediatric Chat National Med/Peds Residents' Association - organization for residents, practioners and medical students interested in combined internal medicine and pediatrics.National Med/Peds Residents' Association Neonatology Network - information and communication platform for neonatologists and pediatricians.Neonatology Network Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.Pediatria OnLine Pediatric Critical Care Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood illnesses.Pediatric Database (PEDBASE) Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10 2001.Pediatric Endocrinology Conference Pediatric Endoscopic Photos - illustrating intestinal problems in children.Pediatric Endoscopic Photos ***-Example

103 Internet global subject directories: Yahoo! for pediatrics Health > Medicine > Pediatrics: link to a digital library (health sciences) for young patients ***-Example

104 Internet global subject directories: Yahoo! to pediatrics organisations Health > Medicine > Pediatrics > Organizations: link to the American Academy of Pediatrics ***-Example

105 Internet global subject directories: Yahoo! links to pediatrics schools Health > Medicine > Pediatrics >Schools, Departments, and Programs University of Rochester - partnership between pediatric residents and community-based agencies that serve children and their families.University of Rochester Michigan State University@ Royal College of Paediatrics and Child Health - responsible for training, examinations, professional standards, and organisation of child health services for the UK.Royal College of Paediatrics and Child Health Tohoku University University of Alabama at Biringham - programs and training opportunities in pediatrics. Also contains faculy information and sub-speciatlty descriptions.University of Alabama at Biringham … ***-Example

106 Internet global subject directories: Yahoo! Example: link to an e-journal Health > Medicine > Pediatrics >Journals: link to an electronic journal **--Example

107 Internet global subject directories: Yahoo! Example: link to a directory Health > Medicine > Pediatrics >Web directories: link to a directory of sites on the WWW related to pediatrics **--Example

108 Internet global subject directories: Yahoo! Example: link to a directory Health > Medicine > Pediatrics >Web directories: link to a directory of sites on the WWW related to pediatrics **--Example

109 Internet global subject directories: searching with a query in Yahoo! (1) The directory of Yahoo! can not only be browsed, but can also be searched with a query. However, in this way the hierarchical structure is not well exploited. For the formulation of a search query, Yahoo! can provide automatic assistance related to spelling and word variations. For instance: After searching for “Capetown”, Yahoo! Answers: Other Spellings: Try searching for cape town instead.cape town ***-Example

110 Internet global subject directories: searching with a query in Yahoo! (2) When such a query does not provide results, then Yahoo! uses a much larger external Internet index to execute a query based on textual search statements. The chosen Internet index has varied over time. This mechanism is not made very clear and may confuse the user. ***-Example

111 Internet global subject directories: Yahoo! and full-text search engines The company Yahoo! started and became famous by offering a WWW global subject directory. Afterwards it has offered many other services and has become one of the mostly used WWW portals. In 2003, Yahoo! also owns 3(!) big Internet search engines: All the Web, AltaVista, Inktomi ***-Example

112 Internet global subject directories: Britannica A hypertext global subject directory can be found at http://britannica.com/ http://britannica.com/ Entries are rated. Accessible free of charge. Combined and integrated with a great encyclopedia. **--Example

113 Internet global subject directories: BUBL link A hypertext global subject directory to more than 10 000 WWW sites for the higher education community can be found at http://bubl.ac.uk/link/ http://bubl.ac.uk/link/ Accessible free of charge. **--Example

114 Internet global subject directories: Google directory A hypertext global subject directory can be found at http://directory.google.com/ http://directory.google.com/ Accessible free of charge. Based on the Netscape DMOZ Open Directory Project. Do not confuse this with the famous Google WWW search engine. ***-Example

115 Internet global subject directories: LookSmart A hypertext global subject directory can be found at http://www.looksmart.com/ http://www.looksmart.com/ Accessible free of charge. **--Example

116 Internet global subject directories: Open Directory Project A hypertext global subject directory can be found at http://www.dmoz.org/ http://www.dmoz.org/ The contents is also used in other systems, such as Google Directory and Webbrain. Accessible free of charge. ***-Example

117 Internet global subject directories: Resource Discovery Network A collection of hypertext subject directories that focus on academic information sources can be found at http://www.rdn.ac.uk/ http://www.rdn.ac.uk Together these lead to more than 30 000 selected WWW sites. Accessible free of charge. ***-Example

118 Internet global subject directories: Webbrain A hypertext subject directory can be found at http://www.webbrain.com/ http://www.webbrain.com/ Based on the Netscape DMOZ Open Directory Project. Uses more advanced techniques for the visualisation of the directory contents than DMOZ or Google. Accessible free of charge. **--Example

119 Internet global subject directories: Webbrain: screenshot **--Example

120 Internet global subject directories: evaluation criteria - desiderata (1) Usage free of charge? Wide coverage? Up to date? Frequent updates? Only few dead / broken links? Good coverage of the sources in that part of the world in which you are interested? ***-

121 Internet global subject directories: evaluation criteria - desiderata (2) Does the manager of the directory refuse to give priority to sites that want to pay to get a prominent place in the directory? Easy user interface? Short response times? Are mirror sites available closer to you for faster response? Good presentation, description of each site? ***-

122 Internet global subject directories: evaluation criteria - desiderata (3) Is a rating, appreciation, review offered for each listed site? Is translation of documents offered free of charge? Good documentation and online help? Good help desk available? High stability and reliability? ***-

123 Internet global subject directories: evaluation criteria - desiderata (4) Are other services offered from the same site or with the same interface? Is the subject directory integrated with other services? Additional services can be »an Internet index or a WWW index or a gateway to such an index for searching with a query »weather, travel guides, flight and hotel reservations, maps,... »WWW-based e-mail and e-mail address directories »auctions through WWW ***-

124 ***- Internet subject directories: non-global, more specific systems a directory limited to sources in/of a country or region a directory restricted to a specific subject domain (“portal”) a global subject directory the complete WWW can lead to

125 Internet subject directories focusing on a specific subject domain: example A directory of sites on the WWW related to pediatrics **--Example

126 Internet subject directories focusing on a specific subject domain (Part 1) Marine science and oceanography: »http://oceanportal.org/ = http://ioc.unesco.org/oceanportal/http://oceanportal.org/http://ioc.unesco.org/oceanportal/ Engineering, mathematics, computing: »http://www.eevl.ac.uk/http://www.eevl.ac.uk/ »http://www.ub.lu.se/eel/http://www.ub.lu.se/eel/ Civil engineering: »http://www.icivilengineer.com/http://www.icivilengineer.com/ Fishing: »http://www.onefish.org/http://www.onefish.org/ ***- Examples

127 Internet subject directories focusing on a specific subject domain (Part 2) Medicine and healthcare: general: http://www.achoo.com/ http://www.medmatrix.org/ http://www.medscape.com/ http://www.omni.ac.uk Medicine and healthcare: General pediatrics: http://GeneralPediatrics.com http://www.medscape.com/pediatricshome http://www.pedinfo.com/ ***- Examples

128 Internet indexes: automated search tools Several systems allow to search for and to locate many items (addressable resources) in the Internet in a more systematic, direct way than by only browsing/navigating. These systems do NOT search the contents of computers through the real Internet in real time and completely when a user makes a query. Searching in that way would be much too slow due to limitations in the technology. ****

129 Internet indexes: scheme of the mechanism **** User searching for Internet based information Internet client hardware and software user interface to a search engine Internet information source Internet index search engine Internet crawler and indexing system database of Internet files, including an index

130 Internet indexes: description of the mechanism Each of these search systems is based on: a database of links to pages / URLs that can be retrieved by searching with queries through a big index that is built machine-made on the basis of the contents, the texts, of these pages (to build this database and to keep it up to date, pages are continuously collected from the Internet by a “robot” computer software system) a search system with a user interface in a WWW form, to allow the user to search through that database ****

131 Internet indexes: building their database ***- Inverted file, full text index, register of the database User Records derived from the input and stored in the database Internet documents fed into the database management system Indexing Retrieval

132 Internet indexes: AltaVista ***- The primary search interface can be found in the US. The following addresses all lead to the same information: »http://www.altavista.com/http://www.altavista.com/ »http://www.av.com/http://www.av.com/ »http://av.com/http://av.com/ Mirror site in UK: »http://uk.altavista.com/http://uk.altavista.com/ »http://www.altavista.co.uk/http://www.altavista.co.uk/

133 Internet indexes: AltaVista: features Allows full text searching of the WWW Offers relevance ranking of search results Allows also advanced Boolean searching (in “Advanced” mode) Offers a link to an Internet subject directory Offers links to systems to find images, sounds… (multimedia) in the Internet ***-

134 Internet indexes: All the Web ***- The search interface can be found at: http://www.alltheweb.com/ http://alltheweb.com/ http://www.alltheweb.com/ http://alltheweb.com/ You can search the WWW and ftp servers. The database is one of the biggest. Not only HTML and plain text files, but also the full text of many Adobe PDF files is indexed. Offers also a module to search for pictures/images. Offers spelling suggestions in the search interface.

135 Internet indexes: Google (Part 1) http://www.google.com/ Full-text searching is possible of many files that are available through the WWW. Not only HTML and plain text pages are covered, but also the first part is indexed of many files in other file formats, such as »Adobe PDF, »Microsoft Word, Microsoft Excel, Microsoft PowerPoint »Rich Text Format… ****

136 Internet indexes: Google (Part 2) One of the most popular systems in 2001, 2002, 2003… For retrieval an algorithm is used that takes into account the links between WWW pages. A retrieved page is ranked higher when »many sites/pages point to it »“important” sites/pages point to it Another famous search system Netscape Search is based on Google (at least in 2003) http://search.netscape.comhttp://search.netscape.com ****

137 Internet indexes: Google refers to a dictionary In Google, the words used in a search query are returned to the user with hyperlinks to a dictionary and to a thesaurus on the WWW, that can be used partly free of charge. The dictionary can learn the user more about the meaning of the words used in the query. **--

138 Internet indexes: Google refers to a dictionary: display **--Example

139 Internet indexes: from Google into a dictionary **--Example

140 Internet indexes: Google refers to a thesaurus In Google, the words used in a search query are returned to the user with hyperlinks to a dictionary and to a thesaurus on the WWW, that can be used partly free of charge. The thesaurus can of course show the user synonyms, narrower terms, related terms for the word. In this way, this system can be used to expand a search query, so that the query better covers the search concept. ***-

141 Internet indexes: from Google into a thesaurus ***-Example

142 Internet indexes: Google can expand a query: how? ***- If you want to retrieve more documents, then you can request Google to include synonyms of one or several of the words in your query in an automatic way. This works since 2003. You can do this by putting a tilde ~ in front the selected word. Example of a query: word1 ~word2 word3 word4

143 Internet indexes: Google can expand a query: comment ***- Of course, this is only a “quick and dirty” method. The system does not really understand your information need. Manual, intellectual expansion of a query should yield better results.

144 Internet indexes: Google additional features Besides a system to search for WWW pages, Google offers also »a subject directory »searching for images/pictures on the WWW »searching an archive of Usenet messages + posting to Usenet groups »searching for news Thus Google has become a great integrator / aggregator. ****

145 Internet indexes: Google as a company The important competitors of Google are »The Yahoo! subject directory system »All the Web and AltaVista Internet search engines These are all owned by the same U.S. company, Yahoo!, since 2003. **--

146 Internet indexes: MSN Web Search Offered free of charge by Microsoft. You can search for WWW content. Since 1998. Famous system, because the search interface can be found with the search functions that have been built into one of the most widespread Internet browser, Microsoft Internet Explorer, and because it is offered by http://search.msn.com/ http://search.msn.com/ ***-Example

147 Internet indexes: MSN Web Search Is based on an Internet index created by another company. But in 2003, Microsoft has started building its own WWW crawler. **--Example

148 Internet indexes: Scirus Allows you to search for manually selected scientific information (only) on the WWW. This includes »the peer-reviewed articles in the journals that are published in ScienceDirect by Elsevier, that can be downloaded in full-text format only when a fee has been paid to the publisher »scientific open archives files, that contain scientific research articles that can be downloaded free of charge. The search interface: http://www.scirus.comhttp://www.scirus.com ***-Example

149 Internet indexes: Scirus features Offered free of charge by Elsevier. Is partly based on the Fast WWW search system that is also used by Alltheweb. Offers access to information ordered according to some classification system / taxonomy. Offers not only access to files in html format, but also to files in PDF, PostScript and other formats. ***-Example

150 Internet indexes: Teoma Allows you to search for information on the WWW. Offers a feature that is not offered by most other search systems: categorization = classification = refinement = categorization = clustering of search results, to help the user coping with the problem of ambiguity of meaning of the search query that was made The search interface: http://www.teoma.com/http://www.teoma.com/ **--Example

151 Internet indexes: Teoma example Example of coping with ambiguity: searching for pascal gives results related to the philosopher and to the computer programming language: **--Example

152 Internet indexes: coverage Internet indexes do not cover all static documents on the WWW. Most indexes grow and their “size ranking” is variable. If exhaustive results are desired, then more than one Internet index search system should be used. ****

153 Internet indexes: coverage and size of each index Most indexes grow and their “size ranking” is variable. The biggest systems in 2003: »Google ! »AltaVista »All the Web (serving also Lycos) »Systems based on the INKTOMI database of WWW pages. ****

154 **-- Internet indexes: delay in indexing new pages The great, well known, international Internet indexes have a delay of more than 1 month in indexing new pages. (according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.) So they are not suitable to search for rapidly changing recent information (such as “news”) (unless they index a small selection of important news sites more frequently.)

155 **-- Internet indexes: specialised systems More specialised search engines / systems can yield better result sets: »higher recall »higher precision Specialised Internet indexes / search engines can be found for instance in the directory http: //directory.google.com /Top /Computers /Internet /Searching /Search_Engines /Specialized/

156 the complete WWW covered by a global / international Internet index covered by an index limited to sources in/of a country or region Internet indexes: non-global, regional systems **--

157 the complete WWW Internet indexes: subject-specific, specialised systems covered by a global / international Internet index covered by an Internet index limited to sources related to a specific subject **--

158 Internet indexes: variations among various systems Besides their common aims and characteristics, we can nevertheless see differences, variations among the searchable Internet index systems. To illustrate these variations and to assist Internet users to make a decision on which search system to use, the following list of some features and evaluation criteria can be useful. ***-

159 Internet indexes: general evaluation criteria - desiderata Is usage free of charge? How complete is the coverage? Is the coverage good (or poor) for a particular geographic region? Is the coverage good (or poor) for a particular type of documents? Is the searchable database up to date? Is the database updated frequently? Do the search results contain only few dead (broken) links? ***-

160 Internet indexes: indexing + searching evaluation criteria - desiderata (1) Does the database system work with full text indexing of each document that has a place in the database, so that full text searching is possible? Is the complete text indexed and searchable, even for very long documents? ***-

161 Internet indexes: indexing + searching evaluation criteria - desiderata (2) Are the contents of meta-fields also indexed to make them searchable? ***-

162 Internet indexes: indexing + searching evaluation criteria - desiderata (3) Does the system index also the text in files on the web that consist of non-ASCII codes to make these also searchable and retrievable? For instance files in the format of the various versions of »Microsoft Word (DOC), Microsoft PowerPoint (PPT, PPS), Microsoft Excel »Adobe Acrobat Portable Document Format (PDF) ***-

163 Internet indexes: indexing + searching evaluation criteria - desiderata (4) Field indexing, so that searching limited to the contents of a particular field is possible? for instance: HTML title,HTML keywords, URL, date, link,Java applet, text, image file, sound file,video file... ***-

164 Internet indexes: indexing + searching evaluation criteria - desiderata (5) Does the system offer powerful search options like »searching for terms composed of several words, in queries like “word1 word2” with the words enclosed in double quote characters »truncation of words in a query? »Boolean search combinations? »an unlimited number of search terms in a query? »proximity/nearby/adjacency searching, with operators like “word1 NEAR word2” or “word1 ADJ word2” ***-

165 Internet indexes: indexing + searching evaluation criteria - desiderata (6) »spelling check of search terms in the query, and suggesting spelling variations? »automatic expansion of the search terms in the initial user’s query, to achieve a higher recall, for instance by —automatic stemming of words in a query —including synonyms —including narrower terms —including translations into several other languages ***-

166 Internet indexes: indexing + searching evaluation criteria - desiderata (7) Can the results be limited to a certain time period? For instance based on the date »of the file as noted by the server computer, or »of the most recent indexing of the file Is the user interface easy to understand and efficient to use? Is a user interface offered in your own language? ***-

167 Internet indexes: indexing + searching evaluation criteria - desiderata (8) Is the search/query also submitted to another database to obtain more results? for instance: to a book database to obtain book descriptions besides WWW documents ***-

168 Internet indexes: indexing + searching evaluation criteria - desiderata (9) Is spamming filtered out, to give other pages a better chance of turning up in the result set? Can the system cluster presumed duplicate documents in the results? Or does the system simply eliminate presumed duplicate documents from its database? ***-

169 Internet indexes: output evaluation criteria - desiderata (1) Short response times? Are mirror sites available closer to you for faster response? Does the system rank the items in the result set according to their presumed relevance? Possibility to combine Boolean retrieval with relevance ranking of results? ***-

170 Internet indexes: output evaluation criteria - desiderata (2) Can the results be ordered according to date »of the file as noted by the server computer, or »of the most recent indexing of the file Can the results be ordered according to size? Can the system rank the results (documents) on the basis of the number of WWW hyperlinks to that document? The system does NOT place/rank some results (documents) higher in the results list, on the basis of payments by the producer of those documents to the search system company. ***-

171 Internet indexes: output evaluation criteria - desiderata (3) Are advertisements / sponsored links / sponsored results clearly distinguished from normal (not sponsored) search results? Good and detailed summary of each result available? Does the system offer a good presentation format of each result (document/page/item)? For instance: are search terms indicated / highlighted in the results? ***-

172 Internet indexes: output evaluation criteria - desiderata (4) Is any evaluation offered (automatic?) of the quality of each result, besides ranking in an order related to probable relevance and importance of the results? Can all the results (documents) from the same site be grouped together (clustered)? ***-

173 Internet indexes: output evaluation criteria - desiderata (5) Are results (retrieved documents) grouped / classified / categorized / clustered by the search system, on the basis of the subjects of the documents and are these presented as groups / clusters / classes / categories to the user of the search system, to assist the user in coping with the problems that can be caused for instance by multiple meanings of words used in a search query. Is translation of documents offered free of charge? ***-

174 Internet indexes: output evaluation criteria - desiderata (6) Is any fact extraction from the information sources offered, in an attempt to answer the query more directly than by offering only links to documents? Term suggestion: Does the system analyse the search results of the first query, to find frequently occurring terms and to suggest these to the user as new and potentially interesting additional query terms? ***-

175 Internet indexes: output evaluation criteria - desiderata (7) High stability and reliability? No large variations/fluctuations in the results from identical searches at different times. Relevance feedback: Can the user indicate among the search results of a first query the “good, relevant” and the “bad, irrelevant” results, so that the system can use this information to offer better results in a second query? ***-

176 Internet indexes: output evaluation criteria - desiderata (8) Relevance feedback 2: even better: Can the user indicate among the search results of a first query + “good, relevant” results, - as well as the “bad, irrelevant” results, so that the system can use this information to suggest + additional, new interesting query terms that can be included in a second query, - as well as query terms that should be excluded in a second query? ***-

177 Internet indexes: help evaluation criteria - desiderata Good documentation and online help? Good help desk available? ***-

178 Internet indexes: current awareness evaluation criteria - desiderata Can the search system provide updated results, through electronic mail for instance, as a current awareness tool? ***-

179 Internet indexes: other services evaluation criteria - desiderata Other services available besides the normal WWW index: »index to news resources, that is more frequently updated?! »Internet subject directory?! »anonymous ftp file index? »gopher index? »searchable Usenet newsgroups archive? »white pages = people finder = addresses =... »WWW-based e-mail and e-mail address directories »auctions through WWW ***-

180 ?? Question ?? Why do different Internet search engines (in most cases) give different results for an identical search, even though they have access to the same (all) documents on the Internet? ***-

181 Internet indexes for citation searching: introduction Some Internet indexes / search engines allow you to search for documents / pages / URLs that link to a particular page, to some URL that you already know (such as one of the web pages that you have developed or that you have made available yourself). Linking to a URL is similar to citing an information source. Such search systems can be used to analyse web citations. Web citations are sometimes named “sitations”, referring to the term “web site”. **--

182 Internet indexes for citation searching: query syntax For details about the required query syntax, query formulation, see the online manual or help pages of the search system that you want to use. Take care to search for all variants such as »//web-server-computer.country/website/index.html »//web-server-computer.country/website/ »//web-server-computer.country/website **--

183 Internet indexes for citation searching: link versus linkdomain Do not confuse links to a particular web page, using for instance a query like “link:this_page.html” with links to a whole web domain, using for instance a query like “linkdomain: this_site” **--

184 Internet indexes for citation searching: examples of systems AltaVista! - Note that “Simple search” and “Advanced search” may give different results!? + Allows truncation, which can be used to search not only citations of a WWW page, but also of a whole WWW site. + Allows Boolean searching, which can be used to exclude self-citations. Google Lycos **--Examples

185 Internet indexes for citation searching: applications Citation searching on the WWW or on an intranet can be used »to get an idea of the importance, the fame, the impact of a particular web document, as measured by the number of links/citations to that page »to find out who has considered a particular page as interesting enough to make a link to »to find comments/criticisms on a particular web document **--

186 ?? Question ?? In spite of the high popularity and the quality of the Google Internet index search system, there are still limitations in the search features. Which limitations? In spite of the high popularity and the quality of the Google Internet index search system, there are still limitations in the search features. Which limitations? ***-

187 Internet indexes: Google limitations Google does NOT offer/allow »an unlimited number of search terms in a search query »manual or automatic truncation of words in a query »manual or automatic stemming of words in a query »full Boolean search formulations (OR, AND, brackets…) like in (sea OR ocean) AND (pollution OR contamination) ***-

188 Internet indexes: Google limitations Google does NOT offer/allow »a proximity/nearby operator in the queries (such as NEAR) »full-text searching of complete text in the case of very long documents »a relevance feedback mechanism ***-

189 Internet indexes: Google limitations Google does NOT offer/allow »automatic classification/clustering/categorization of retrieved WWW pages, to cope with the problem of the natural ambiguity of meaning of the terms that were used in the search query »any evaluation of documents retrieved and offered as results ***-

190 Internet indexes: Google limitations Google does NOT offer/allow »fact extraction from the information sources, in an attempt to answer the query more directly than by offering only links to documents »a current awareness service, by email for instance (Googlealert exists however, a service independent of Google, but based on Google) ***-

191 Meta- search systems: scheme 1 User Client computer + WWW client program WWW server computer Internet WWW WWW server computers with Internet search systems In Out **--

192 Meta- search systems: scheme 2 User Client computer + Multi-threaded Internet search client program Internet WWW WWW server computers with Internet search systems In Out **--

193 **-- Meta- search systems: vocabulary “multi-threaded Internet search systems” “multiple search systems” “multi-search systems” “meta-search systems” “intelligent Internet search agents” “Internet meta-search tools”...

194 **-- Meta- search systems: relations User an Internet meta-search system Internet search system 1 Internet search system collected database 1 WWW pages Internet search system 2 Internet search system collected database 2

195 **-- Meta-search systems: server-based or client-based Online accessible on a server in the Internet. On the client, “meta-search software”.

196 **--Examples Meta-search systems: server-based systems http://www.all4one.com http://www.bytesearch.com http://www.cyber411.com http://www.dogpile.com = http://dogpile.com/http://www.dogpile.comhttp://dogpile.com/ http://www.go2net.com = http://www.metacrawler.comhttp://www.go2net.comhttp://www.metacrawler.com http://www.kartoo.com http://www.mamma.com http://www.profusion.com http://www.search.com http://www.vivisimo.com = http://vivisimo.com/http://www.vivisimo.comhttp://vivisimo.com/

197 **--Example Meta-search systems: server-based: example: Vivisimo

198 **--Example Meta-search systems: server-based: example: Vivisimo

199 **--Example Meta-search systems: server-based: example: Vivisimo Vivisimo adds value by analysing the retrieved results / hits / links / WWW documents, in order to cluster / group / categorize / classify / map these under headings / classes / categories, to make further selections by the user / searcher easier and faster. Vivisimo can accomplish this on the fly, that is WITHOUT pre-processing the documents before the search.

200 **--Example Meta-search systems: server-based: example: Vivisimo In the test search for a family name, Vivisimo succeeded in clustering documents related to different persons with the same family name. For comparison: the clustering search engine Teoma did not accomplish this.

201 **--Example Meta-search systems: server-based: example: Dogpile The clustering software of Vivisimo is also used on other systems. Example: http://dogpile.com/http://dogpile.com/

202 **--Example Meta-search systems: server-based: example: Kartoo

203 **--Example Meta-search systems: server-based: example: Kartoo Kartoo offers an advanced graphical user interface. Before you can exploit the system, reading the manual is recommended.

204 **--Examples Meta-search systems: client-based: example Example: Copernic http://www.copernic.comhttp://www.copernic.com

205 **-- Meta-search systems: advantages (Part 1) + Saves time when otherwise more than only 1 Internet index would have to be used one after the other; for instance when searching for specific information that is hard to find in any single Internet index. + Some meta-search systems provide a useful integration of the results they get from the various primary search systems, with a removal of repeated results.

206 **-- Meta-search systems: advantages (Part 2) + Some server-based and client-based meta-search systems show links among retrieved pages. + Some client-based meta-search systems allow storage on the client computer of a search query for later, repeated usage/application; application of such a system even allows excluding resulting documents that were already retrieved in an earlier search.

207 **-- Meta-search systems: advantages (Part 3) + Can add value, for instance by analysing the results / hits so that they can be clustered / grouped / categorized / classified, to make further selections by the user / searcher easier and faster. Example: http://www.vivisimo.comhttp://www.vivisimo.com

208 **-- Meta-search systems: disadvantages (Part 1) - It is not always clear through which Internet indexes the meta-search system will search. - Not all meta-search systems can search all the major primary search systems; for instance Google is normally NOT included. -The systems are often slower than a direct, primary search system. - Only a limited number of the results that can be obtained from the various Internet indexes are shown.

209 **-- Meta-search systems: disadvantages (Part 2) - Some specific or advanced features of the individual search systems cannot be used through all the meta- search systems, such as: »Boolean searching, »proximity searching, »field searching, »categorization / clustering of search results, »...

210 Internet information sources Coverage of Internet directories and Internet indexes **** A global Internet index A global Internet directory

211 Internet indexes cover only a part of the Internet: introduction (1) ***- The “visible” part of Internet The “hidden, invisible” part of Internet and the WWW, (that is not searchable using a global index like Alltheweb, AltaVista, Google...)

212 ?? Question ?? Which information on the Internet is not covered by many searchable Internet indexes? ***-

213 Internet indexes cover only a part of the Internet: introduction (2) ***- Why can Internet indexes find only a part of what is in fact available through the Internet? 1.Quantitative technical limitations: Each Internet search system has indexed only a part of the static WWW pages that are available for indexing. 2.Qualitative technical limitations: Besides the static WWW pages that Internet search engines try to cover, many other, quite different sources exist, that are also available through the Internet, but that are not incorporated in those search engines.

214 Internet Internet indexes cover only a part of the Internet: scheme ***- WWW Databases and file archives accessible through the Internet telnet ftp... telnet ftp... CGI, ASP,... Rapidly changing information, such as news Information accessible only when passwords are used Static indexable texts in the WWW ( = on HTTP server computers) covered partly by Internet indexes Word files PDF files

215 Database accessible over the Internet: a famous example: Medline/PubMed ***- Example

216 Internet indexes cover only a part of the Internet: conclusion for users When you want to retrieve information about a particular subject from the Internet, use not only WWW indexes, but use also other sources accessible through the Internet »databases! (book and journal bibliographies, library catalogues, archives of group messages, directories, atlases,…) »rapidly changing information, such as news »information accessible only when passwords are used »anonymous ftp file archives »e-mail based interest groups; Usenet newsgroups ***-

217 Internet indexes cover only a part of the Internet: conclusion for producers When you want to distribute information on a global scale, through the Internet, realize that many potential users will not search your database(s), but only one of the global Internet indexes. **--

218 ***- Gateways to Internet databases accessible free of charge Most Internet search engines search classical, static WWW pages and not databases accessible through the WWW. However, some systems offer a gateway to search databases on the Internet. Examples: »http://www.completeplanet.com/http://www.completeplanet.com/ »http://www.invisible-web.net/http://www.invisible-web.net/ (See also other more general directories/overviews/lists of Internet information sources.)

219 ***-Example Gateways to Internet databases accessible free of charge: invisibleweb

220 ***- Hybrid systems to find information on the Internet Some systems require a search in words from the searcher, but they do not rely on classical Internet indexes. Example: Ask Jeeves

221 ***-Example Hybrid systems to find information on the Internet: Ask Jeeves Ask Jeeves tries to “answer questions” of searchers, by analysing the natural language queries and by referring to selected sources on the Internet. http://www.askjeeves.com/ http://www.ask.com/ http://www.aj.com/

222 Internet: who owns the search tools? In 2003: The company Yahoo! owns »the most famous global Internet subject directory »3 (!) Internet full-text search engines: All the Web, AltaVista, Inktomi The company Google owns »the most famous Internet full-text search engine »one of the best Internet image search engines »a gateway to old and new Usenet news messages ****

223 ?? Question ?? How can you easily find new pages that become accessible on the WWW about a particular topic that is interesting for you? ***-

224 Current awareness services focusing on WWW pages: introduction Tracking changes in one or more public access pages on the WWW or finding new pages, is possible in an automated way, »by using one of the available, suitable, programs loaded on your client workstation! example: the advanced version of Copernic that is not available free of charge »through “alert” services based on a server on the WWW —that track updates for the user/subscriber —and send alerts by email to the user/subscriber ***-

225 Current awareness services focusing on WWW pages: modified versus new Several systems exist that can track changes / modifications / updates in a particular existing WWW page for you, even free of charge. Some systems can find new pages on the WWW for you. ***-

226 Current awareness services focusing on WWW pages: Google Alert Can discover relevant changed or new WWW pages for you in the future. Is based on the external Internet index Google. Works with search queries given by you that are stored on their server computer. Free of charge, at least up to 2003. http://www.googlealert.com/ ***-Example

227 Current awareness services focusing on WWW pages: Google Alert ***-Example

228 Online access information sources and services Public access book databases ****

229 Public access book databases: introduction Even in this age of Internet-based information sources, a lot of information is still distributed in the form of printed books. The contents of most books is (still) not available on the Internet. Most general Internet search tools do NOT allow you to find out about the existence of books that may be interesting for you. So, specific search tools to find books can be useful. ****

230 Public access book databases: an overview (Databases by publishers.) Fee-based databases by commercial providers Databases by book distributors / bookshops! Online public access catalogues of »local libraries, »national libraries (which produce and offer normally their national bibliography)! »big, famous libraries!! (Databases of computer-based versions of books.) ****

231 Public access book databases: which one to use? For years, the market of bibliographic information on books was limited to the services and databases of subscription-based bibliographic providers. Nowadays, the WWW provides a key to unlock many possibilities to find bibliographic information. Which book database should be preferred for particular applications is not clear for most librarians or end-users. ****

232 Suitable book databases? AIMRECOMMENDED SYSTEMS To find book titles about a specific subject / topic ? To find book titles published before 1990 ? To find a book title through a title search ? To find the price of a book ? To be informed regularly about new books ? ***-

233 Public access book databases by commercial producers To find currently available books, some databases assembled by commercial producers can be interesting. Example: Global Books in Print These databases offer formal descriptions of books, prices of the books, short descriptions of the contents with subject terms… However, access to such a database is not free of charge and can be expensive (in comparison with alternatives). ****

234 Public access book databases provided by bookshops To find currently available books, the bibliographic databases assembled by big bookshops are interesting. Several offer a good coverage and are accessible free of charge. The added price information can be useful for the acquisition and accounting department of a library or if an individual user wants to buy a book. Some provide a current awareness service, also free of charge. ****

235 Book databases accessible free of charge: examples in U.S.A. Amazon.com (US): http://www.amazon.com/ http://www.amazon.co.uk/ note: amazon, NOT amazone Subject description is poor. http://www.amazon.com/http://www.amazon.co.uk/ Barnes and Noble (US): http://www.bn.com/ http://www.bn.com/ ****Examples

236 Book databases accessible free of charge: examples in Europe Blackwell’s on the Internet (International, academic books): http://www.blackwell.co.uk/ http://www.blackwell.co.uk/ VLB for books in German http://www.buchhandel.de/ http://www.buchhandel.de/ For books in French http://www.chapitre.com http://www.chapitre.com Boeknet - De Nederlandse Internet Boekhandel (Dutch) http://www.boeknet.nl/ http://www.boeknet.nl/ ***-Examples

237 Book databases accessible free of charge: for old books To find used, secondhand, rare, hard-to-find, and out-of-print books around the world: abebooks http://www.abebooks.com/ http://www.abebooks.com/ ***-Examples

238 Free public access bibliographic book database + price comparisons Even comparisons of the catalogues of shops of books (as well as of music, movies and many other goods) are available free of charge. See for instance »http://www.bookfinder.com/http://www.bookfinder.com/ »http://www.dealtime.com/http://www.dealtime.com/ ****

239 Example of an international public access dissertation database The dissertation database of UMI is available from: http://wwwlib.umi.com/dissertations/ http://wwwlib.umi.com/dissertations/ The most current two years are available without charge. ***-Examples

240 Database of links to the full text of many books A database (accessible free of charge ) of links to the full text of many books: http://digital.library.upenn.edu/books/ http://digital.library.upenn.edu/books/ **--Examples

241 Online Public Access Catalogues of libraries **** Mainly to find older books, the catalogues of libraries can be useful. Most are accessible online and free of charge.

242 Online Public Access Catalogues = OPACs: definition ***- Online Public Access Catalogue: a term used to describe any type of computerized library catalog offered to the public by online login

243 Online Public Access Catalogues of the big famous libraries For instance: Library of Congress (USA) Their coverage is good. They offer the best subject descriptions. Access is free of charge. So they form excellent sources to find books about a particular subject/topic. ***-

244 Online Public Access Catalogues: The British Library Accessible online via WWW: Since 2000: http://blpc.bl.uk/http://blpc.bl.uk/ Access free of charge ***-Example

245 Online Public Access Catalogues: catalogues of national libraries National libraries are first of all an outstanding source for the local publications. The national libraries are the most reliable source for bibliographic searching and verification. ***-

246 Online Public Access Catalogues: union catalogues of libraries Some systems offer access to the merged catalogues of several libraries, so-called ‘union catalogues’. Example: Copac http://www.copac.ac.uk/ is accessible free of charge. http://www.copac.ac.uk/ ***-

247 Online Public Access Catalogues: simultaneous searching Some meta-search services allow simultaneous, parallel searching in one search action over several databases of libraries and bookdealers. The result depends on the availability and functionality of the target systems. + The coverage is very good. - Search options are rather limited. **--

248 Online Public Access Catalogues: simultaneous searching: examples Infoball http://www.infoball.de http://www.infoball.de Karlsruher Virtueller Katalog http://www.ubka.uni-karlsruhe.de/kvk.html http://www.ubka.uni-karlsruhe.de/kvk.html **--Examples

249 Public access book databases: evaluation criteria - desiderata (1) Is usage free of charge? Wide coverage? Specialized coverage of books »in your preferred language? »on particular subjects / topics? »published in a specific country? »published in a particular time period? »of particular types (such as conference proceedings)? Up to date? Frequent updates? ***-

250 Public access book databases: evaluation criteria - desiderata (2) Does the database offer besides each formal book descriptions also »an abstract / summary / description of the contents? »a table of contents? »the price? »information about the publisher? »titles of related books? »reviews by readers? ***-

251 Public access book databases: evaluation criteria - desiderata (3) Full text indexing of each item (book description) in the database, so that full text searching is possible? Field indexing, so that searching limited to the contents of a particular field is possible? for instance »the title »the date of publication »the author »the publisher »the language ***-

252 Public access book databases: evaluation criteria - desiderata (4) Does the database producer improve retrieval by »adding subject terms, or »by classifying the books in categories ***-

253 Public access book databases: evaluation criteria - desiderata (5) Powerful search options: »truncation of words in a query? »stemming of words in a query? »Boolean search combinations? combined field searching? »proximity searching? »spelling check of your search terms? »suggestions by the system of spelling variations of the words in the query »translation of your search terms in several other languages? ***-

254 Public access book databases: evaluation criteria - desiderata (6) Can the user browse through subject categories that are used in the book database? Is a user interface offered in your own language? Easy user interface? Relevance ranking of results? Possibility to combine Boolean retrieval with relevance ranking of results? Can results be limited to a certain time period? Short response times? ***-

255 Public access book databases: evaluation criteria - desiderata (7) Can the results be ordered according to date, size, origin...? Good presentation of each result? For instance: Are search terms highlighted? Can search results be downloaded, well structured with field tags? (For instance to allow incorporation of the data in another database.) ***-

256 Public access book databases: evaluation criteria - desiderata (8) Does the system offer a current awareness service, sending information on new titles that may be of interest to you? ***-

257 Public access book databases: evaluation criteria - desiderata (9) Are other services offered from the same site or with the same interface? Is the system integrated with other services? Additional services can be »searchable databases of videos, of music CD’s, CD-ROMs, DVDs, all for sale also »WWW-based e-mail and e-mail address directories »auctions through WWW **--

258 Public access book databases: evaluation criteria - desiderata (10) Is the database system accessible through the Z39.50 Internet database search and retrieve protocol? In other words, is the database Z39.50 compliant? This would offer the following advantages: »The system can then be searched starting from one of the available Z39.50 client software packages. »The database can be then searched simultaneously with other Z39.50 compliant databases and the results from the various databases can be merged. This is useful for rare, uncommon, special items that are difficult to find. **--

259 Recommended book databases AIMRECOMMENDED SYSTEMS To find book titles about a specific subject / topic Library of Congress, British Library, (Amazon) To search for book titles published before 1990 national libraries, Barnes&Noble, Infoball, Alapage, Abebooks Book title search in general Library of Congress, British Library, Infoball To find the price of a book Global Books in Print, Infoball, online bookshops To be informed regularly about new books Amazon, Alapage, Bol ***-

260 General conclusion concerning book databases The one and only, international, complete, ideal, bibliographic database does NOT exist, but the united forces of the different available book databases should be satisfying. ***-

261 Online access information sources and services Fee-based online public access information services ****

262 Types of online access information systems: “free” versus “fee” A lot of the information on the Internet is available free of charge, but another part is only accessible when a fee is paid to the producer and / or the distributor. The first commercial computer systems that make information available online were born around 1975. Most of them are now also available through the Internet. Some organisations pay these fees for some sources and then organise access, so that the members of the organisation can retrieve and exploit the information as if it is free of charge. ****

263 Types of online access information systems: “free” versus “fee” **** Public access information sources free of charge Fee-based online information services (NOT free of charge)

264 Types of online access information systems: “free” for members only **** Public access information sources free of charge Fee-based online information services (NOT free of charge) Fee-based online information services, made accessible “free of charge” by an institute to its members

265 Fee-based online access services: examples (Part 1) Location of the computer(s)U.S.A. U.S.A. U.S.A. U.S.A., Taiwan, UK Switzerland U.S.A. Name America On Line OCLC Ovid Technologies CompuServe Cambridge Data-Star Dialog EBSCO ***-Examples

266 Fee-based online access services: examples (Part 2) Location of the computer(s) U.S.A. U.S.A. U.S.A., The Netherlands,... Germany - U.S.A. - Japan The Netherlands... Name Elsevier ScienceDirect Factiva ISI (Web of Knowledge, JCR,…) LexisNexis MSN (Microsoft) Prodigy Silver Platter STN Swets-Blackwell (e-journals)... ***-Examples

267 Online information services: various names for similar systems (fee-based) online (access) information service (fee-based) online (access) computer service databank database vendor host computer aggregator... ***-

268 Database hosts / distributors: evaluation criteria - desiderata (1) Contract not required? A priori payment not required? Satisfactory stability / history / evolution / future of host? Low costs of data communication? Many databases available? Whole records available (or only parts)? Frequent updates? Whole database available? As one file or fragmented? ***-

269 Database hosts / distributors: evaluation criteria - desiderata (2) Low price of access? Low price of information? Good searching facilities? (cfr. desiderata for Internet indexes) Can the indexes of more than one database be searched simultaneously? ***-

270 Database hosts / distributors: evaluation criteria - desiderata (3) Online indication of costs? Practice free of charge? Good manuals, documentation and online help? Training courses available? Quality? Good help desk available? Gateway service offered?... ***-

271 Databases of online public access databases Example »Gale directory of databases ! Their coverage: »online access databases »(databases accessible on CD-ROM) »... ***-

272 Databases of databases: Gale Produced in U.S.A. Not free of charge Available in various formats: »printed »on CD-ROM »online via the host systems Data-Star, Dialog, with a payment required for each use »online through the Internet through various hosts, for a fixed price per year to be paid in advance ***-

273 Online use of external databanks: how to learn working with a host? Ideally, combine all of the following: »Using computer-assisted learning offered by the host organisation »Attending demonstrations and courses offered by the host organisation »Studying manuals offered by the host organisation »Watching a video about online information searching »Studying handbooks »Online practicing! **--

274 Online access information sources and services Online access databases about journal articles ****

275 Online access databases about journal articles: overview Thousands of fee-based online access databases offer bibliographies or full-texts of journal articles in particular subject domains and published by many publishers. Many publishers offer searchable bibliographies, but only of their own publications. (for instance Emerald, Elsevier) Only few large databases offer access to bibliographies of articles published in journals from many publishers, free of charge. ****

276 Online access databases about journal articles: Ingenta (1) Ingenta Journals allows you to search a bibliographic database of millions of journal articles, including titles, authors, in many cases abstracts. Searching is free of charge. ***-Example

277 Online access databases about journal articles: Ingenta (2) Payment is required to receive the full text of an article. Ingenta has acquired Uncover in 2000. Available from »http://www.ingenta.co.uk/http://www.ingenta.co.uk/ »http://www.ingenta.com/http://www.ingenta.com ***-Example

278 Online access databases about journal articles: Article@INIST Article@INIST allows you to search in a bibliographic database, NOT full-text, (Journal articles, journal issues, books, reports, conferences, doctoral dissertations) at the Institut de l'Information Scientifique et Technique, France. Does not offer usage of classification or thesaurus. Searching is free of charge. Available from http://form.inist.fr/public/eng/conslt.htmhttp://form.inist.fr/public/eng/conslt.htm Payment is required to receive the full text of an article. ****Example

279 Online access databases about journal articles: Infotrieve Infotrieve allows you to search free of charge in a bibliographic database of the articles of more than 20 000 journal titles and conference proceedings, NOT full-text. Available from http://www3.infotrieve.com/http://www3.infotrieve.com/ Payment is required to receive the full text of a document. Current awareness services are also offered free of charge: the table of contents of new issues of the journals that you have selected are sent to you by email. ***-Example

280 Online access databases about journal articles: Scirus This is a specialised Internet index that allows you to search for selected scientific information (only) on the WWW. This includes the peer-reviewed articles in the journals that are published in ScienceDirect by Elsevier. An article can be downloaded in full-text format only when a fee has been paid to the publisher The search interface: http://www.scirus.comhttp://www.scirus.com ***-Example

281 Online access databases about journal articles: Scirus features Offered free of charge by Elsevier. Is partly based on the Fast WWW search system that is also used by Alltheweb. Offers access to information ordered according to some classification system / taxonomy. ***-Example

282 Online access databases about journal articles: Eric Eric allows searching a bibliographic database of articles and other documents in the fields of information science and education Searching is free of charge Available from http://ericir.syr.edu/Eric/ http://ericir.syr.edu/Eric/ Payment is required to receive the full text of a document. **--Example

283 Online access databases about journal articles: Medline Medline produced by the National Library of Medicine (USA) allows searching a bibliographic database of articles in the field of medicine. free of charge available from many sites, including »PubMed of the National Library of Medicine (USA) and »Ingenta **--Example

284 Online access databases: Web of Science The Web of Science (or more recently the Web of Knowledge) offers access through the WWW to a database of bibliographic descriptions of scientific journal articles in all subject domains. This database is (only) available to members of organisations / institutes / companies / consortia that pay a yearly, high fee to the producer/publisher of the database. This database is not only suitable for subject searching, but also for citation searching. ***-

285 Online access information sources and services Online information sources about journal titles ***-

286 ***- Online information sources about journal titles: introduction Besides directories / catalogs / overviews /databases / lists of electronic, computer-based, online accessible newsletters, newspapers, journals, and besides databases about published articles in journals (bibliographic databases), information is also available through the WWW about journal titles in general: their exact names, name changes, editors, prices, formats (printed or electronic online), full text availability online, …

287 ***-Example Online information sources about journal titles: example Available free of charge: http://www.publist.com/ about classical journalshttp://www.publist.com/

288 Online access information sources and services Electronic newsletters and journals ***-

289 Electronic newsletters and journals: introduction ***- Since the end of the 1990s, electronic journals have become a new communication medium that cannot be neglected. Author / Sender Editor Reader / Receiver

290 **-- Electronic newsletters and journals: variations on a theme We can distinguish several methods »of distribution and access »of formatting the information (PDF, HTML,…) »of pricing and licensing »of restricting access (authentication and authorization of legitimate users) »to integrate access to e-journals with access to other information sources

291 Electronic newsletters and journals: various types and the price of access ***- We can distinguish various types: »equivalents of a version printed on paper —published almost simultaneously —print version published long time before electronic version = deliberate long delay for the electronic version »purely electronic publications Price of access: from free of charge to very expensive

292 Electronic newsletters and journals: access and distribution methods ***- Many different methods are used: »anonymous ftp »gopher »WAIS / Z39.50 »electronic mail, listserv,... »Usenet News »loaded on local systems in universities or institutes »http, WWW ! »Open Archives Harvesting Protocol + http, WWW

293 Electronic newsletters and journals through the WWW ***- The WWW has become the most important platform for access to electronic newsletters and journals.

294 Electronic newsletters and journals: example ***-Example

295 **-- Electronic newsletters and journals: authentication To control access to fee based electronic journals some method for authentication and authorization is used by publishers or distributors: »On the basis of the range of IP-addresses of the computer workstations used by the organisation »On the basis of a username and password couple —that are constant, permanent —or that are changed often by the information provider »Or based on a combination of those methods

296 **-- Electronic newsletters and journals: authentication problems Up to now, the authentication methods are far from perfect: »Authentication by IP-address gives problems with users on “external”, “unknown” workstations outside the simple IP- address range. »Authentication by passwords is complicated and passwords cannot be kept secret.

297 **-- Electronic newsletters and journals: the flow of information is hindered The free flow of scientific information is hindered by several related phenomena in traditional publishing: »copyright of the publishers, so that copying and further distribution is forbidden, »high prices to be paid to commercial publishers to access information, »need to implement authentication + authorisation technology, as required by commercial publishers.

298 **-- Electronic newsletters and journals: Open Archives Initiative OAI The free flow of scientific information is hindered by traditional distribution methods. As a reaction and as a partial solution, the Open Archives Initiative movement tries to develop and to implement alternative publishing methods that are based on publishing through computers and the Internet.

299 ***- Electronic newsletters and journals: problems and challenges There is no central database with all article titles, summaries, and full contents. There is not even a central, complete and up to date directory of journal titles. There is no standard licensing/pricing method. Not all electronic journals are accessible through 1 user interface. Many passwords must be used. Archiving (By whom? Forever?)

300 **-- Electronic newsletters and journals: integration with other sources It is not (yet) clear and straightforward how electronic journals should be integrated »in a library collection »in a library web site »in the catalogue database »in interlibrary lending (depends on licensing agreement for each individual journal)

301 **-- Electronic newsletters and journals: integration and access methods Access can be possible through »A gateway offered by a subscription agent or the publisher »A commercial bibliographical database »A web-based static listing of journal titles »A web-based OPAC (for instance in the MARC 856 field) »A local searchable database for e-journals »linking mechanisms based on Open URL, such as SFX (commercialised by Ex Libris) and Vlink COMPLEXITYCOMPLEXITY

302 Directory of Open Access Journals The Directory of Open Access Journals is a directory of electronic journals that can be accessed free of charge. Available since May 2003. http://www.doaj.org/ ***-

303 ***- Directory of Open Access Journals: screenshot

304 **-- Online access to electronic journals in developing countries The costs of access to scientific journals is high, while developing countries have few funds available. Therefore several initiatives have been taken to provide access at a lower price or free of charge to users in developing countries. An overview of such initiatives/projects/plans is available online through http://www.library.yale.edu/~llicense/develop.shtml http://www.library.yale.edu/~llicense/develop.shtml

305 Online access information sources and services Finding multimedia files on the Internet ****

306 **** Finding multimedia files on the Internet: introduction Several public access search systems are available free of charge, to search the Internet for multimedia files: »images / pictures (either artwork, either photos, or both) »sound / audio files (music, speeches...); video

307 **** Finding images on the Internet: introduction Several public access search systems are available free of charge to search for images / pictures (either artwork, either photos, or both) on the Internet. When searching for images, the search results from such a system offer not only links to the image files on the Internet, but also directly small versions of the images (so-called “thumbnails”).

308 **-- Finding images on the Internet: function The systems to find images on the WWW function by searching for your search terms, for instance in the name of the file or in the path on the disk to the file that contains the image in the link leading to the image in the text nearby the image on a web page in the title of the web page that contains the image in the alternate HTML ALT tag text for the image (that may be present for users that apply a program for browsing that does not display graphics)

309 ****Examples Finding images on the Internet: examples of search engines http://alltheweb.com/ !!http://alltheweb.com/ http://gallery.yahoo.com/ !http://gallery.yahoo.com/ http://images.google.com/ !!! or through http://www.google.com/ The largest database in this category (at least in 2002, 2003). For each result, not only a thumbnail is offered, but also directly the readable URL; this makes it easy to guess the relevance of the document.http://images.google.com/http://www.google.com/

310 ****Examples Finding images on the Internet: examples of search engines http://multimedia.lycos.com/ http://www.altavista.com/ !! (also audio and video, choose not the normal text search, but IMAGES in the user interface.)http://www.altavista.com/

311 ****Examples Finding images on the Internet: examples of search engines http://www.ask.com/ or http://www.aj.com/ or http://aj.com/ Ask Jeeves. Offers no indication of the number of images retrieved, which is a disadvantage when many pictures are found, but only a few can be seen at the time.http://www.ask.com/ http://www.aj.com/ http://aj.com/ http://www.ditto.com/ !http://www.ditto.com/

312 **** Examples Finding images on the Internet: screen shot of a Google image search

313 Online access information sources and services Future trends ****

314 Online access information: future trends An increasing amount of information becomes available online. A growing amount of this online information becomes available free of charge. The quality of server and client software is growing.  A consequence is: An increasing number of end-users searching for information online. ****

315 Online access information: conclusion In the case of simple information needs, the WWW and the search tools can work like “magic”. However, in the case of more complicated information needs, there is still is no “magic button” that brings you immediately to all the required information. ****

316 Evaluations in information retrieval ****

317 Evaluations in information retrieval: summary The following gives an overview of approaches that are applied to assess the quality of »information retrieval systems, and more concretely of search systems »the resulting set of records obtained after performing a query in an information retrieval system Note: This should not be confused with assessing the quality and value of the content of an information source. ****

318 Evaluations in information retrieval: introduction The quality of the results, the outcome of any search using any retrieval system depends on many components / factors. These components can be evaluated and modified to increase the quality of the results more or less independently. ****

319 Evaluations in information retrieval: important factors The information retrieval system ( = contents + system) The user of the retrieval system and the search strategy applied to the system **** Result of a search

320 Evaluations in information retrieval: why? (Part 1) To study the differences in outcome/results when a component of a retrieval system is changed, such as »the user interface »the retrieval algorithm »addition by the database of uncontrolled, natural language keywords versus keywords selected from a more rigid, controlled vocabulary ****

321 Evaluations in information retrieval: why? (Part 2) To study the differences in outcome/results when a search strategy is changed. To study the differences in outcome/results when searches are performed by different groups of users, such as »children versus adults »inexperienced users versus more experienced, professional information intermediaries/professionals ****

322 Evaluations in information retrieval: the simple Boolean model Boolean model: # items in database = # items selected + # items not selected # Items selected = # relevant items + # irrelevant items Relevant Yes 1 In Irrelevant No 0 Out ****

323 Relevant items in a database: scheme **** Dependent on the aims, independent of the search strategy Relevant items! (In most cases the small subset) Irrelevant / NOT relevant items (In most cases the large subset)

324 Selecting relevant items by searching a database: scheme **** Dependent on the aims, independent of the search strategy Selected and relevant! Selected but not relevant Not selected but relevant Not selected and not relevant Dependent on the aims and dependent on the search strategy

325 Recall: definition and meaning **** Definition: # of selected relevant items “Recall” = ------------------------------------------------- * 100% Total # of relevant items in database Aim: high recall Difficulty: in most practical cases, the total # of relevant items in a database cannot be measured.

326 Selecting relevant items: recall **** Selected and relevant! Selected but not relevant Not selected but relevant Not selected and not relevant

327 Recall: how to use the concept of recall **-- Using the same database, variations in recall express the effect of search variations »Variations in search terms »Use of a classification scheme »Use of a thesaurus »...

328 ?? Question ?? How can you change your search strategy to increase the recall? ***-

329 Precision: definition and meaning **** Definition: # Of selected relevant items “Precision” = --------------------------------------- * 100% Total # of selected items Aim: high precision

330 Selecting relevant items: precision **** Selected and relevant! Selected but not relevant Not selected but relevant Not selected and not relevant

331 ?? Question ?? How can you change your search strategy to increase the precision? ***-

332 ?? Question ?? When you change your search strategy to increase the precision, which consequence do you expect for the recall, in most cases? ***-

333 Relation between recall and precision of searches 100% Recall 0 0 Precision 100% Ideal = Impossible to reach in most systems Ideal = Impossible to reach in most systems Search (results) ****

334 Recall and precision should be considered together Examples: Increase in retrieved number of relevant items may be accompanied by an impractical decrease in precision. Precision of a search close to 100% may NOT be ideal, because the recall of the search may be too low. Make search / query broader to increase recall ! Poor (low) precision is more noticeable than bad (low) recall. ****

335 Evaluation in the case of systems offering relevance ranking Many modern information retrieval systems offer output with relevance ranking. This is more complicated than simple Boolean retrieval, and the simple concepts of recall and precision cannot be applied. To compare retrieval systems or search strategies, decide to consider for comparison a particular number of items ranked highest in each output. This brings us to for instance: “first-20 precision”. ****

336 Evaluating the quality of information Documentary information sources: evaluating their quality ****

337 Documentary information sources: evaluating their quality We should always be critical when using information sources, in view of »the widely varying degrees of quality of information sources, and of »the costs associated with searching, finding, using information. ****

338 Documentary information sources: evaluation criteria (1) Is the information valid, reliable, trustworthy, genuine, authentic? Is the author honest? Is the source objective, not subjective, without cultural or political or ideological or commercial bias? Is the origin an individual or a company or an organisation? Is the publication sponsored by some company or organisation? ***-

339 Documentary information sources: evaluation criteria (2) Is the information accurate, correct? Who is the author or producer? Has the source an author or a producer with a high expertise, a good reputation, good qualifications? Can the author be contacted for clarification or discussion? Was the information reviewed, edited, improved, corrected, censored, approved, verified, before publication? Do experts agree on the information provided? ***-

340 Documentary information sources: evaluation criteria (3) Is the information source unique? Does it offer a great amount of primary information, which is not obtainable from other sources? Is the information complete? Is the work available in its entirety? Does the source offer a wide coverage? Is the source comprehensive, substantive? Is the information current enough, up to date? Is a publication date provided? Is an expiration date provided? ***-

341 Documentary information sources: evaluation criteria (4) Does the document provide suitable references, so that you can verify statements and find older suitable information sources? Good clear format and lay-out of the information / User-friendly information system / Easy for users to orientate themselves within the resource and to find their way around it? Good user support / Good customer support? Is the type of distribution medium appropriate? (print, e-mail, online,...) ***-

342 Documentary information sources: evaluation criteria (5) Is the information what you want? If not, then reassess your needs and consider other types of information as well. ***-

343 Documentary information sources: evaluation criteria (6) Is the information suitable for your level of understanding of the subject? Is the document popular, suitable for the general public, for students, for professionals, for scholarly/academic use…? Does it report new, primary research (survey, experiment, observation, measurement, invention) or is it a review of sources published earlier? Does the information repeat or confirm what you already know, or is it complementary, contradictory, new? ***-

344 Evaluating the quality of information Computer-based information sources: evaluating their quality ***-

345 Computer-based information sources: evaluation criteria (Part 1) ***- Besides more general criteria applicable to all information sources, for those sources that are based on computers and networks we see the following criteria: Easy to navigate? »User-friendly information system? »Easy for users to orientate themselves within the resource and to find their way around it? »Is the resource organised into manageable chunks of information that can be browsed easily?

346 Computer-based information sources: evaluation criteria (Part 2) ***- »Is a contents page or index offered that describes what is contained within the site? »Are there good navigational links within the pages (e.g. 'back', 'forward', 'home') »Are the links clearly labeled? »Is the navigation process supported by images? »Is there a single downloadable file for documents that exist as a series of separate pages? »Is there a search facility within the resource?

347 Computer-based information sources: evaluation criteria (Part 3) ***- Good user support? »Good support that is offered to users to help them answer queries and problems that arise whilst using the resource? »Good computer-based, contextual help, documentation, training materials or tutorials? »E-mail contact(s) and telephone number(s) available?

348 Computer-based information sources: evaluation criteria (Part 4) ***- Based on appropriate technologies? »Are technologies and standards used that will enable users to access and utilize all aspects of the resource? »Does the resource avoid that proprietary software should be used? »Does the resource avoid the use of proprietary extensions to HTML, which some browsers will not be able to recognize?

349 Computer-based information sources: evaluation criteria (Part 5) ***- »Does the format allow access to the resource for all users, even for instance sight impaired and those who can only navigate by using the keyboard? Information integrity / High stability of the contents / Low volatility of the contents? »Is there adequate maintenance of the information content?

350 Computer-based information sources: evaluation criteria (Part 6) ***- System integrity? »Site integrity relates to the stability of the site over time. This usually relates to the work of the site manager or web master. »Realise that individual sites can be moved or withdrawn at any time by those responsible for publishing information on the Internet, and that addresses, file structures, formats and interfaces can be altered without warning. »Is the site current and up to date?

351 Computer-based information sources: evaluation criteria (Part 7) ***- »Is the site proven to be or expected to be durable in nature? »Is the site adequately administered and maintained?

352 Computer-based information sources: The Internet Detective A tutorial in English about how to assess the quality of WWW-based information resources can be accessed online free of charge through the WWW: http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective **--

353 These slides will be available through the WWW from http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/ http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/ References to publications about this subject and more slides are available through the WWW from http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/ http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/ (note: BIBLIO and not biblio)

354 Questions? Suggestions? Topics for further discussion?

1 Finding information through the Internet and the WWW: a tutorial Vrije Universiteit Brussel Information and Library Science,

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