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1 Finding scholarly information through the Internet and the WWW Vrije Universiteit Brussel Information and Library Science,

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Presentation on theme: "1 Finding scholarly information through the Internet and the WWW Vrije Universiteit Brussel Information and Library Science,"— Presentation transcript:

1 1 Finding scholarly information through the Internet and the WWW Vrije Universiteit Brussel Information and Library Science, University of Antwerp Belgium Presented at Indian Statistical Institute, Bangalore Centre, 8th Mile Mysore Road, India 28 February 2005

2 2 The slides should be available from (note: BIBLIO and not biblio)

3 3 Databases and computerized information retrieval (on fundamental difficulties in information retrieval, and how to take these into account.) Thesaurus systems for better information retrieval. Continued… - contents - summary - structure - overview of this tutorial

4 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 Continued… - contents - summary - structure - overview of this tutorial

5 5 Online access information sources and services (2) »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 Continued… - contents - summary - structure - overview of this tutorial

6 6 Online access information sources and services (3) »finding books »finding journal articles »fee-based databases »using fee-based electronic journals »open access electronic journals »using a link resolver to find appropriate documents End - contents - summary - structure - overview of this tutorial

7 7 -Interruptions -Questions -Remarks -Discussions are welcome

8 8 Databases and computerized information retrieval Introduction

9 9 Comparison Information retrieval: the basic processes in search systems Information problem Representation QueryIndexed documents Representation Retrieved, sorted documents Text documents Evaluation and feedback

10 10 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.

11 11 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

12 12 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

13 13 Layered structure of a database Database (File) Records Fields Characters + in many systems: relations / links between records

14 14 A simple database architecture: all records together form a database The ‘salami architecture’ = ‘sliced bread architecture’ »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

15 15 Databases and computerized information retrieval Text retrieval and language

16 16 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) 

17 17 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.)

18 18 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 

19 19 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. 

20 20 Text retrieval and language: a word is not a concept (a’’) »synonyms! (such as : Latin names of species in biology besides the common names, scientific names besides common names of substances in chemistry…) 

21 21 Text retrieval and language: a word is not a concept (a’’’) »narrower terms, more specific terms (such as particular brand names); including terms with prefixes (for instance: viruses, retroviruses, rotaviruses,...) »spelling variations (such as UK English versus US English); possible variations after transliteration 

22 22 Text retrieval and language: a word is not a concept (b) Method to solve the problem at the time of database production: »adding to each database record those codes from a classification system or terms from a thesaurus system that are relevant, and providing the user with knowledge about the system used; in some cases, this process is computerized (with intellectual intervention or completely automatic)

23 23 Text retrieval and language: a word is not a concept (b’) »However, this solution is not perfect: —Addition of terms by humans from a controlled vocabulary / from a thesaurus is not easy and time consuming. Consequences: –the added value lags behind the availability of the document –the process can delay access to the document –the process is expensive —Moreover, in practice, most users of the resulting database do not exploit this method offered.

24 24 Text retrieval and language: a word is not a concept (c) Method to solve the problem, provided by the computerized retrieval system: »offering to the user a partly computerized access to the particular subject description system used by the database producer, and then linking to the database for searching »computerized, automatic, analysis of the ‘free text’ search terms applied in a query by the user, for transparent ‘mapping’ to the corresponding particular classification codes, categories, or thesaurus terms used by the database producer

25 ?? Question ?? Which problems in text retrieval are illustrated by the following sentences? 25 

26 26 Time flies like an arrow. Fruit flies like a banana. ?

27 27 Time flies like an arrow. Fruit flies like a banana.

28 28 Time flies like an arrow. Fruit flies like a banana. OK!

29 29 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. 

30 30 Text retrieval and language: ambiguity of meaning (a’) Example of a word: »Pascal the philosopher »Pascal the computer language Example 

31 31 Text retrieval and language: ambiguity of meaning (a’’) Example of sentences: »The banks of New Zealand flooded our mailboxes with free account proposals. »The banks of New Zealand flooded with heavy rains account for the economic loss. Example 

32 32 Text retrieval and language: ambiguity of meaning (a’’’) Problem: Ambiguity of meaning may be the cause of low precision. Word Concept 

33 33 Text retrieval and language: ambiguity of meaning (b) Method to solve the problem at the time of database production: »adding to each database record codes from a classification system or terms from a thesaurus system, and providing the user with knowledge about the system used; in some cases, this process is computerized (completely automatic or with intellectual intervention);

34 34 Text retrieval and language: ambiguity of meaning (b’) Method to solve the problem, provided by the computerized retrieval system: »offering to the user a partly computerized access to the subject description system and then linking to the database for searching

35 35 Text retrieval and language: ambiguity of meaning (b’’) »searching normally (without added value), but adding value by categorizing the retrieved items in the presentation phase to assist in the ‘disambiguation’; this feature is offered for instance by —the public access module of the book catalogue of the library automation system VUBIS at VUB, Belgium, when a searching items that were assigned a particular keyword

36 36 Text retrieval and language: ambiguity of meaning (b’’’) »Natural language processing of the queries: linguistic analysis to determine possible meanings of the query, which includes disambiguation of words in their context: “lexical” analysis = at the level of the word “semantic” analysis = at the level of the sentence However, most queries are short and therefore it is difficult to apply semantic analysis for disambiguation.

37 37 Text retrieval and language: ambiguity of meaning (b’’’’) »Natural language processing of the documents: linguistic analysis to determine possible meanings of a sentence, which includes disambiguation of words in their context: “lexical” analysis = at the level of the word “semantic” analysis = at the level of the sentence However, most retrieval systems do not apply this complicated method.

38 38 A word is not a concept A concept is not a word Word1 Word2 Word3 Concept1 Concept2 Concept3 A concept cannot be “covered” by only 1 word or term; this may be the cause of low recall of a search. The meaning of many words is ambiguous; this may be the cause of low precision of a search.

39 39 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.

40 40 Databases and computerized information retrieval Hints on how to use information sources

41 41 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

42 42 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. Limit your search to a specific country or region if required. Work iteratively. Keep a record of your work.

43 43 Hints on how to use information sources: overview (Part 3) Do not only focus on a single source. 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.) Be critical: not all information is correct or useful.

44 44 Hints on how to use information sources: overview (Part 4) In computer-based retrieval systems, consider applying »truncation of search terms (using a symbol like * or ?) »combine search terms, using —Boolean operators: ORAND / +NOT / AND NOT / - —proximity operators (for instance “NEAR”) —phrase searching (“word1 word2”) »searching limited to a field (for instance URL, title…)

45 45 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.

46 46 Hints on how to use information sources: Boolean combinations 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

47 47 Hints on how to use information sources: Boolean combinations 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...

48 48 Hints on how to use information sources: Boolean queries Most text search systems understand the basic Boolean operators typed in capital characters: OR AND

49 49 Hints on how to use information sources: default Boolean operator Find out if there is a default implicit Boolean operator working in the search system that you use. This works even when no operator is used explicitly among words. This can be OR, AND, NEAR...

50 50 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

51 51 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

52 52 Hints on how to use information sources: when to stop searching? Develop a feel for the “curve of diminishing returns”: If you spend too much time, effort, and/or money with too few benefits, you should stop. time / effort / money payoff Time to stop?

53 53 Knowledge organisation: classifications, and thesaurus systems Introduction

54 54 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

55 55 Various related tools / systems / methods / approaches are available: »Classification »Taxonomy »Controlled list of selected keywords »Thesaurus »Ontology »Subject-related metadata »… Knowledge organisation: some tools

56 56 Knowledge organisation: classifications, and thesaurus systems Classifications

57 57 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

58 58 Knowledge organisation: classifications, and thesaurus systems Thesaurus systems

59 59 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

60 60 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

61 61 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.

62 62 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.

63 63 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).

64 64 Thesaurus systems that cover all subjects General systems Universal systems Covering all subjects Broad and shallow systems Horizontal systems

65 65 Thesaurus systems that cover all subjects: examples (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 Examples

66 66 Thesaurus systems that cover all subjects: examples (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

67 67 General thesaurus system through the WWW: screenshot sea Example

68 68 Thesaurus systems covering all subjects: comments An ideal, complete thesaurus that covers all subjects does not exist.

69 69 Thesaurus systems focused on a particular subject Focused on a particular subject domain = narrow and deep, vertical systems

70 70 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: Examples

71 71 Knowledge organisation: classifications, and thesaurus systems Classification systems versus thesaurus systems

72 72 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)

73 73 Online access information sources and services Introduction

74 74 Online information sources: summary The following gives a general overview of online accessible information sources. This overview is not limited to or focusing on a particular concrete subject domain/area.

75 75 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.

76 76 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?

77 77 Internet based information sources: problems / difficulties (Part 3) Change is the only constant: Information sources are constantly changing, growing, but sometimes disappearing.

78 78 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.

79 79 Internet based information sources: problems / difficulties (Part 5) Slow: The Internet is in many places and for many applications not yet fast enough.

80 80 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.

81 81 Internet based information sources: how many? how much information? More than 10 terabyte (= gigabyte) of text data (in 2001) More than 10 million WWW sites (in 2003) More than million (= 4 billion) unique URLs in the total Internet (in 2004)

82 82 Increasing number of online public access databases Source: Gale Directory of Databases, 1997.

83 83 Online access information sources and services Types of online access information systems

84 84 Primary versus secondary computer sources / systems / services Primary sources /systems /services directly useful Secondary sources /systems /services »helping to access / use the primary services »“travel agencies”, “navigation services”,...

85 85 Types of online access information systems by contents Documents (with or without hyperlinks) Catalogues of editors and bookshops Online public access library catalogues (OPACs) Community/Campus-Wide Information Systems (CWIS) Online access databases about journal articles Electronic newsletters and journals Computer file archives (documents, programs) Interest groups (for instance Usenet Newsgroups)...

86 86 Types of online access information systems by access method Remote login information systems and bulletin board systems (BBS) (telnet in the Internet) Anonymous ftp servers, in the Internet Usenet News servers (nntp in the Internet) Gopher servers, in the Internet Wide Area Information Servers (WAIS), in the Internet World Wide Web servers = http servers (WWW), in the Internet...

87 87 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)

88 88 Types of online access information sources by file format For instance: »TXT (ASCII) »DOC »HTM, HTML, SHTML,… »PDF »PCX »TIF, TIFF »GIF »JPG »PNG »AVI »MPG »ASF »…

89 89 Commercial information provided through the Internet Most of the information that is freely available on the WWW is provided by commercially oriented organisations. Thus that information is not objective or scientific in most cases, but subjective or perhaps even misleading, and certainly attracting more attention than more scientific information. (Of course many information sources are also provided by commercial organisations that belong to the so-called information industry, but these are bound to supply more objective information of high quality, as this is their way to survive commercially.)

90 90 Online access information sources and services Dictionaries and encyclopaedias accessible through the WWW

91 91 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.

92 92 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 Example

93 93 Dictionaries accessible through Internet and the WWW: compilation A compilation/collection of dictionaries can be searched simultaneously and free of charge: Example

94 94 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

95 95 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

96 96 Encyclopedias accessible through Internet and the WWW: examples The Canadian Encyclopedia (in English and in French): »http://thecanadianencyclopedia.com/http://thecanadianencyclopedia.com/ Example

97 97 Encyclopedias accessible through Internet and the WWW: overviews A list / overview of encyclopedia on the Internet: Other lists of encyclopedia on Internet can be found as a part of more general directories of Internet-based information sources. Example

98 98 Online access information sources and services Internet search functions built in browser software

99 99 The Internet search functions built into browsers Some Internet search functions are built into common leading browsers like »Microsoft Internet Explorer »Netscape When connected to the Internet, you can use »The functions behind the “Search button” »Searching through the “Address” form

100 100 The Internet search button of browsers: introduction Common graphical browsers provide a search function and a search button. Examples: Netscape, Microsoft Internet Explorer

101 101 The Internet search button of browsers: comments (Part 1) Such a search function offers in fact no searching, but (only) a link to a WWW site, often in the USA, which offers links or gateways to search tools on other servers. It is faster in many cases to contact search tools directly.

102 102 The Internet search button of browsers: comments (Part 2) The gateways may offer only a limited view on the properties of the real search tool used. Such a search function can confuse users who may think that the searching capability is built more or less into the browser software, while searching relies on external servers.

103 103 Searching with browsers using the address form: introduction A search for particular Internet documents can be performed by typing in keywords in the address form, when you are connected to the Internet, for instance with »Microsoft Internet Explorer »Netscape This is based on transmitting the keywords to some Internet index through the Internet.

104 104 Searching with browsers using the address form: comments + An advantage is the ease of use. - A disadvantage is that it is less clear what really happens, than when you access a well chosen and well known Internet directory or Internet index directly.

105 105 Online access information sources and services Internet directories and indexes

106 106 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)

107 107 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)

108 108 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!

109 109 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.

110 110 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.

111 111 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.

112 112 Internet global subject directories: searching directories with a query Many of the Internet directories include an index to search their contents with a query. However, then the assisting classification structure is not well exploited and the user should be aware of the problems and difficulties of information retrieval with natural language queries. Furthermore, the possibility to use the system in this way may be confusing, as these directories are not real full- text Internet indexes, like those provided by other search tools.

113 113 Internet global subject directories: Yahoo! A hypertext global subject directory can be found at and at many other sites, including Entries are NOT rated. Accessible free of charge. Example

114 114 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 Pediatric Endocrinology Conference Pediatric Endoscopic Photos - illustrating intestinal problems in children.Pediatric Endoscopic Photos Example

115 115 Internet global subject directories: Yahoo! for pediatrics Health > Medicine > Pediatrics: link to a digital library (health sciences) for young patients Example

116 116 Internet global subject directories: Yahoo! to pediatrics organisations Health > Medicine > Pediatrics > Organizations: link to the American Academy of Pediatrics Example

117 117 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 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

118 118 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

119 119 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

120 120 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

121 121 Internet global subject directories: Britannica A hypertext global subject directory can be found at Entries are rated. Accessible free of charge. Combined and integrated with a great encyclopedia. Example

122 122 Internet global subject directories: BUBL link A hypertext global subject directory to more than WWW sites for the higher education community can be found at Accessible free of charge. Example

123 123 Internet global subject directories: Google directory A hypertext global subject directory can be found at Accessible free of charge. Based on the Netscape DMOZ Open Directory Project. Do not confuse this with the famous Google WWW search engine. Example

124 124 Internet global subject directories: Librarians' Index to the Internet A hypertext global subject directory can be found at Accessible free of charge. Example

125 125 Internet global subject directories: Open Directory Project A hypertext global subject directory can be found at The contents is also used in other systems, such as Google Directory and Webbrain. Accessible free of charge. Example

126 126 Internet global subject directories: Resource Discovery Network A collection of hypertext subject directories that focus on academic information sources can be found at Together these lead to more than selected WWW sites. Accessible free of charge. Example

127 127 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?

128 128 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?

129 129 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?

130 130 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 and address directories »auctions through WWW

131 131 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

132 132 Internet subject directories focusing on a specific subject domain (Part 1) “Specialised subject directories” or “gateways” Examples: Educational materials in the USA: »http://www.thegateway.org/http://www.thegateway.org/ Marine science and oceanography: »http://oceanportal.org/ = Examples

133 133 Internet subject directories focusing on a specific subject domain (Part 2) 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

134 134 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.

135 135 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

136 136 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

137 137 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

138 138 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/

139 139 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 (Looksmart) Offers links to systems to find images, sounds… (multimedia) in the Internet

140 140 Internet indexes: AltaVista as a company AltaVista and the other leading Internet search engines Alltheweb and Inktomi are owned by the same U.S. company Yahoo! since Their most important competitor is Google.

141 141 Internet indexes: All the Web The search interface can be found at: 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.

142 142 Internet indexes: All the Web as a company All the Web and the other leading Internet search engines AltaVista and Inktomi are owned by the same U.S. company, Yahoo!, since Their most important competitor is Google.

143 143 Internet indexes: Google (Part 1) One of the most popular systems in 2001, 2002, 2003, 2004… 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

144 144 Internet indexes: Google (Part 2) 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…

145 145 Internet indexes: Google (Part 3) Also the contents of some databases can be searched. In other words, not only static WWW pages are harvested and made searchable. Many other search systems on all kinds of WWW sites are based on Google.

146 146 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.

147 147 Internet indexes: Google refers to a dictionary: display Example

148 148 Internet indexes: from Google into a dictionary Example

149 149 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.

150 150 Internet indexes: from Google into a thesaurus Example

151 151 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 You can do this by putting a tilde ~ in front the selected word. Example of a query: word1 ~word2 word3 word4

152 152 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.

153 153 Internet indexes: Google Scholar Google Scholar allows us to search for more scholarly information sources, including journal articles. A beta (test) version was available since November The system is accessible starting from the home page of Google as one of the additional services. The online manual explains the system: The information is harvested in a more or less automatic way from the public WWW and from databases of some scholarly publishers.

154 154 Internet indexes: Google additional features Besides a system to search for WWW pages, Google offers also »a subject directory »its own big database to search for images/pictures »searching an archive of Usenet messages + posting to Usenet groups »searching for news »Google Scholar to search for more scholarly information sources »Google Print to search in the contents of books

155 155 Internet indexes: Google as aggregator Google has become a great integrator / aggregator of systems to access information.

156 156 Internet indexes: Google as a company The important competitors of Google are »The well-established, classical Yahoo! subject directory system »The Yahoo! search engine, new since 2004 »All the Web and AltaVista well-established Internet search engines These are all owned by the same U.S. company, Yahoo!, since 2004.

157 157 Internet indexes: MSN Web Search Offered free of charge by Microsoft. You can search for WWW content. Since 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 Example

158 158 Internet indexes: MSN Web Search Is based on an Internet index created by another company, up to But in 2003, Microsoft has started building its own WWW crawler and search engine. Example

159 159 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: Example

160 160 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. Example

161 161 Internet indexes: Scirus: screenshot Example

162 162 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: Example

163 163 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

164 164 Internet indexes: Mooter 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 clusters are displayed in a diagram. The search interface: Example

165 165 Internet indexes: WiseNut 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: Example

166 166 Internet indexes: WiseNut: screenshot of the guide Example

167 167 Internet indexes: Yahoo! Example An Internet search system is offered through This is offered besides the well-established, classical Yahoo! subject directory. Before 2004, the search system was provided by an external company, most recently by Google. Since 2004, an independent system is offered that is competing with other similar systems. It is probably based on the well-established INKTOMI Internet database that is owned by Yahoo! since 2003.

168 168 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.

169 169 Internet indexes: coverage and size of each index Most indexes grow and their “size ranking” is variable. The biggest systems in : »Google ! »Yahoo search »AltaVista »All the Web »Systems based on the INKTOMI database of WWW pages.

170 170 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 ) 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.)

171 171 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/

172 172 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

173 173 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

174 174 Internet indexes: comparison with library catalogues Most Internet indexes have a larger database than most catalogues. Internet index databases do not correspond as well to the Internet as a normal, good catalogue corresponds to the collection, because the documents on the Internet change more often and their number is growing fast. Most Internet indexes contain all the words of the documents that they index, whereas catalogues only contain short descriptions of the documents.

175 175 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.

176 176 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?

177 177 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?

178 178 Internet indexes: indexing + searching evaluation criteria - desiderata (2) Are the contents of meta-fields also indexed to make them searchable?

179 179 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)

180 180 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...

181 181 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”

182 182 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

183 183 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?

184 184 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

185 185 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?

186 186 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?

187 187 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.

188 188 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?

189 189 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)?

190 190 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.

191 191 Internet indexes: output evaluation criteria - desiderata (6) Is translation offered free of charge of the search result set, that is the list of brief descriptions of retrieved documents? 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?

192 192 Internet indexes: output evaluation criteria - desiderata (7) 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? High stability and reliability? No large variations/fluctuations in the results from identical searches at different times.

193 193 Internet indexes: output evaluation criteria - desiderata (8) 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?

194 194 Internet indexes: output evaluation criteria - desiderata (9) 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?

195 195 Internet indexes: output evaluation criteria - desiderata (10) Does the system check automatically and directly the availability/reachability of WWW pages that correspond to the hyperlinks that the system has retrieved based on your search? The system can then discard invalid/broken links from the results set. This is useful because some links may be “dead/broken” even when they were included earlier in the search system. The Internet and the WWW are volatile media.

196 196 Internet indexes: help evaluation criteria - desiderata Is good documentation and online help available free of charge? Is a good help desk available? Does the system clearly explain which contents (information) is harvested and made searchable and which not, and how completely this contents is covered? Does the system clearly explain the mechanism that is applied to rank the search results in the output?

197 197 Internet indexes: current awareness evaluation criteria - desiderata Can the search system provide updated results, based on your interest profile, through electronic mail for instance, as a current awareness tool?

198 198 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 and address directories »auctions through WWW

199 199 ?? 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?

200 200 ?? 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?

201 201 Internet indexes: Google limitations (Part 1) Google does NOT offer/allow »manual or automatic truncation of words in a query »manual or automatic stemming of words in a query

202 202 Internet indexes: Google limitations (Part 2) 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

203 203 Internet indexes: Google limitations (Part 3) 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

204 204 Internet indexes: evolution, scalability, sustainability? Will one or several Internet indexes (search engines) be able to keep on growing in order to cover a large, interesting part the growing amount of information on the Internet and the WWW with a good retrieval system? In other words, are current systems in this area well scalable and sustainable in an affordable way? The answer to this question is not straightforward.

205 205 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

206 206 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

207 207 Meta- search systems: scheme 1+2 User Client computer + WWW client program Client computer + Multi-threaded Internet search client program WWW server computer Internet WWW WWW server computers with Internet search systems In Out

208 208 Meta-search systems: vocabulary / synonyms “multi-threaded search systems” “multiple search systems” “multi-search systems” “meta-search systems / tools” “intelligent search agents” “federated search systems” “portals” (but this word has more meanings)...

209 209 Meta-search systems: server-based: scheme User Client computer + WWW client program WWW server computer Internet WWW WWW server computers with Internet search systems In Out

210 210 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

211 211 Meta-search systems: server-based or client-based Online accessible on a server in the Internet. On the client, “meta-search software”.

212 212 Examples Meta-search systems: server-based systems = = =

213 213 Examples Meta-search systems: server-based systems An overview of meta-search systems that are based on a server in the Internet is avialable via http: //directory.google.com /Top /Computers /Internet /Searching /Metasearch/

214 214 Example Meta-search systems: server-based: example: Vivisimo

215 215 Example Meta-search systems: server-based: example: Vivisimo

216 216 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.

217 217 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.

218 218 Example Meta-search systems: server-based: example: Dogpile The clustering software of Vivisimo is also used on other systems. Example:

219 219 Example Meta-search systems: server-based: example: Kartoo

220 220 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.

221 221 Meta-search systems: client-based: scheme User Client computer + Multi-threaded Internet search client program Internet WWW WWW server computers with Internet search systems In Out

222 222 Examples Meta-search systems: client-based: example Example: Copernic

223 223 Meta-search systems: advantages (Part 1) + Saves time when otherwise more than only 1 Internet- based information source would have to be used one after the other; for instance when searching for specific information that is hard to find in any single source. In other words: for the same time spent, more sources can be covered. + Only 1 user interface must be learned for many sources.

224 224 Meta-search systems: advantages (Part 2) + The user interface of some meta-search systems can be adapted to the local user population, which is cannot be realised with most external, Internet-based information sources. + In comparison with systems that first integrate/merge the information from several sources into one source and afterwards provide access, meta-search systems provide more up-to-date access to the information.

225 225 Meta-search systems: advantages (Part 3) + 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.

226 226 Meta-search systems: advantages (Part 4) + 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.

227 227 Meta-search systems: advantages (Part 5) + 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:

228 228 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 the famous Google Internet index 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.

229 229 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, »...

230 230 Internet information sources Coverage of Internet directories and Internet indexes A global Internet index A global Internet directory

231 231 Global Internet search tools: a comparison Global Internet directories Only a limited selection of Internet sources Browsing information sources is easy Good for broad searches Global Internet indexes About 1/3 of the Internet is covered by an index Searching requires some skills and knowledge Good for specific, narrow searches Multi-threaded search systems These get information from directories and indexes Searching requires some skills and knowledge Good when even 1 index does not yield information

232 232 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...)

233 233 ?? Question ?? Which information on the Internet is not covered by many searchable Internet indexes?

234 234 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.

235 235 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

236 236 Database accessible over the Internet: a famous example: Medline/PubMed Example

237 237 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 » based interest groups; Usenet newsgroups

238 238 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.)

239 239 Example Gateways to Internet databases accessible free of charge: screenshot

240 240 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

241 241 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 to the user/subscriber

242 242 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.

243 243 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. Example

244 244 Current awareness services focusing on WWW pages: Google Alert Example

245 245 Current awareness services focusing on WWW pages: directly from Google Since Can discover relevant changed or new WWW pages for you in the future. Is based on the popular Internet index Google. Works with search queries given by you that are stored on their server computer. Free of charge. Available at and then see the page with additional services.http://www.google.com/ Example

246 246 Online access information sources and services Public access book databases

247 247 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.

248 248 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.)

249 249 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.

250 250 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 ?

251 251 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).

252 252 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.

253 253 Book databases accessible free of charge: examples in U.S.A. Amazon.com (US): note: amazon, NOT amazone Subject description is poor. Allows full text searching in the contents of a selection of recent books, fre of charge. Barnes and Noble (US): Examples

254 254 Book databases accessible free of charge: examples in Europe Blackwell’s on the Internet (International, academic books): VLB for books in German For books in French Boeknet - De Nederlandse Internet Boekhandel (Dutch) Examples

255 255 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 Examples

256 256 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/

257 257 Example of an international public access dissertation database The dissertation database of UMI is available from: The most current two years are available without charge. Examples

258 258 Databases of links to the full text of many books Databases (accessible free of charge ) of links to the full text of many books: Examples

259 259 Collection of links to public access book databases See for instance Internet directories like Yahoo! that lead to information about books. Examples

260 260 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.

261 261 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

262 262 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.

263 263 Online Public Access Catalogues: The British Library Accessible online via WWW: Since 2000: Access free of charge Example

264 264 Online Public Access Catalogues: The British Library: screenshot Example

265 265 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.

266 266 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 is accessible free of charge.

267 267 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?

268 268 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?

269 269 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

270 270 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

271 271 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?

272 272 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?

273 273 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.)

274 274 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?

275 275 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 and address directories »auctions through WWW

276 276 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.

277 277 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

278 278 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.

279 279 Online access information sources and services Fee-based online public access information services

280 280 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 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.

281 281 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)

282 282 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

283 283 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

284 284 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

285 285 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...

286 286 Online information services: access methods Using generic, common communications software »through the telephone network (telephone + modem) »through X-25 data communication networks »through Internet, using client-server systems: —telnet —WAIS or Z39.50 —http (WWW)! (Examples: (Using client software dedicated to the particular service)

287 287 Online information services: total size of their databases In 1999: The big host systems and the public access WWW pages offer a comparable quantity of information: WWW offered about 8 terabytes (= gigabytes) of text data (according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp ) Dialog offered about 9 terabytes (= gigabytes) (in 1998) »6 billion pages of text »3 million images

288 288 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?

289 289 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?

290 290 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?...

291 291 Databases of online public access databases Example »Gale directory of databases ! Their coverage: »online access databases »(databases accessible on CD-ROM) »...

292 292 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

293 293 Online access information sources and services Online access databases about journal articles

294 294 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.

295 295 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

296 296 Online access databases about journal articles: Ingenta (2) Payment is required to receive the full text of an article. Available from »http://www.ingenta.co.uk/http://www.ingenta.co.uk/ »http://www.ingenta.com/http://www.ingenta.com Ingenta has acquired Uncover in Example

297 297 Online access databases about journal articles: 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 Payment is required to receive the full text of an article. Example

298 298 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 journal titles and conference proceedings, NOT full-text. Available from 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 . Example

299 299 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: Example

300 300 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

301 301 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

302 302 Online access databases about journal articles: Medline through PubMed Example

303 303 Online access databases: Web of Knowledge 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.

304 304 Online access information sources and services Electronic newsletters and journals

305 305 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

306 306 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

307 307 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

308 308 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

309 309 Electronic newsletters and journals through the WWW The WWW has become the most important platform for access to electronic newsletters and journals.

310 310 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?)

311 311 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)

312 312 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 »Special linking mechanisms, based on OpenURL (for instance SFX commercialised by Ex Libris or VLINK commercialised by GEAC) COMPLEXITYCOMPLEXITY

313 313 Electronic newsletters and journals: more than one access method How should libraries and readers/users cope with the fact that many e-journals can be accessed in more than one ways, that is by hyperlinks starting from various information systems or services, while authentication and authorization is NOT fully automated for all those systems, once that a licensing agreement has been established? What mechanisms can offer support for this situation? This is called the “multiple copy problem” or the “appropriate copy problem”.

314 314 Link resolver to guide users to the appropriate e-document: introduction Link resolver = appropriate hyperlink generator: to guide users to the most suitable electronic sources that are appropriate for the specific library or specific user, for instance to cope with the multiple-copy / appropriate copy problem (such as SFX software from Ex-Libris or V-link software from VUBIS-GEAC)

315 315 incoming reference target information source appropriate hyperlink generator Link resolver to guide users to the appropriate e-document: scheme database about local situation “Knowledgebase”

316 316 !! Task - Assignment - Problem !! Find out how you can efficiently access electronic journals from your institute.

317 317 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

318 318 Directory of Open Access Journals: screenshot

319 319 Online access information sources and services Finding multimedia files on the Internet

320 320 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

321 321 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”).

322 322 Examples Finding images on the Internet: screen shot of a Google image search

323 323 Examples Finding images on the Internet: examples of search engines (1) ! or via The largest database in this category (at least in 2002, 2003, 2004). For each result, not only a thumbnail is offered, but also directly the origin with the readable URL; this makes it easier to guess the relevance of the document.http://images.google.com/

324 324 Examples Finding images on the Internet: examples of search engines (2) (also audio and video, choose not the normal text search, but IMAGES in the user interface.)http://www.altavista.com/

325 325 Examples Finding images on the Internet: examples of search engines (3) or or 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/

326 326 Examples Finding images on the Internet: examples of search engines (4) Does NOT directly show the origin of each picture with a readable URL, together with each thumbnail.http://www.picsearch.com/

327 327 Examples Finding images on the Internet: directories of search engines A collection of links to suitable Internet search engines: http: //directory.google.com /Top /Computers /Internet /Searching /Search_Engines /Specialized/Images/

328 328 Example Finding audio on the Internet: example of a search engine Allows you to find sound files in formats aiff, au, wav.

329 329 Example Finding audio and video on the Internet: example of a search engine (use the special multimedia finder)http://www.altavista.com/

330 330 Examples Finding audio and video on the Internet: directories of search engines A collection of links to suitable Internet search engines: http: //directory.google.com /Top /Computers /Internet /Searching /Search_Engines /Specialized /Multimedia/

331 331 Online access information sources and services Evolution and future trends

332 332 Online access information: evolution and future trends An increasing amount of information becomes available online. A growing amount of this online information becomes available free of charge. The quality and ease of use of software on server as well as client is growing.  A consequence is: An increasing number of end-users searching for information online.

333 333 Online access information: easier and more complicated?! At the same time, information retrieval becomes both easier and also more complicated. This may seem strange and contradictory, but it is reality. This is a paradox.

334 334 Online access information: easier information retrieval systems Individual information retrieval systems become easier: »they react faster; »they can provide access to more data/information in one action; »their user interfaces are simple, but more sophisticated, intelligent retrieval algorithms can nevertheless deliver satisfactory results in most simple cases.

335 335 Online access information: more complicated information market The whole information landscape consists of more and more decentralised information sources, each one bringing an individual user interface that should be mastered. Making the right, ideal choice among the sources becomes not easier, perhaps even more complicated every day.

336 336 Online access information: more complicated information market Furthermore, for many sources the accessibility / availability, the user interface, the interlinking, depend on the organisation in which the searcher is active.

337 337 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.

338 338 These slides should be available through the WWW from References to publications about this subject and more slides are available through the WWW from (note: BIBLIO and not biblio)

339 339 Questions? Suggestions? Topics for further discussion?


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