1 Internet en WWW voor het opsporen van wetenschappelijke informatie Paul Nieuwenhuysen Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussel [email protected]

1

Internet en WWW voor het opsporen van wetenschappelijke informatie

Paul Nieuwenhuysen

Vrije Universiteit Brussel,

Pleinlaan 2, B-1050 Brussel

[email protected]

Meer informatie in digitale vorm via

http://www.vub.ac.be/BIBLIO/personal/nieuwenhuysen/courses/opsporen/

IPAVUB

mailto:[email protected]



http://www.vub.ac.be/BIBLIO/personal/nieuwenhuysen/courses/opsporen/

2

Planning van de dag: voormiddag

• Over “informatie”

• De informatiemarkt

• Classificatie- en thesaurus-sytemen

• Information retrieval (+ oefenen van query-formulering)

• Computernetwerken en Internet i.h.b.; telnet en ftp

• World-Wide Web (+ oefenen van “browsing” + “saving”)

• Online toegankelijke informatiebronnen!

»Globale Internet directories (+ demonstratie van Yahoo!)

[Lunch]

3

Planning van de dag: namiddag (deel 1)

• Online toegankelijke informatiebronnen! (vervolg)

»Internet indexes (+ oefenen met AltaVista en NL)

»Bookshop databases (+ oefenen)

»Te betalen databases (+ Gale Directory of Databases)

»Gratis databases met titels van tijdschriftartikels (+ oefenen met Ingenta)

»Vinden van illustraties (+ oefenen met AltaVista)

• Citation searching (+ oefenen met Web of Science)

• Documentleverantie

4

Planning van de dag: namiddag (deel 2)

• (Client-server architectuur)

• (Evaluatie van zoekresultaten)

• [Vrij individueel gebruik van Internet]

5

About “information”

Introductory concepts about information

6

iInformation sources:

evaluation criteria

• authority

• authenticity

• accuracy

• objectivity

• currency / up to date

• wide coverage

• format / lay-out of the information

• reliability

• distribution medium(print, e-mail, online,...)

• price / costs

• stability

• ...

7

The flow of documentary information

Reader/User

Reader/User

Primary sources / systems: mainlyJournal articles / Books /

Electronic mail / Online sources /...

Primary sources / systems: mainlyJournal articles / Books /

Electronic mail / Online sources /...

Secondary sources / systems: mainlyReference works (printed, CD-ROM, online)

Library catalogues, including OPACs...

Secondary sources / systems: mainlyReference works (printed, CD-ROM, online)

Library catalogues, including OPACs...

Author / Sender

Author / Sender

!? Question !? Task !? Problem !?

Why is secondary information created? Why is secondary information created?

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9

Past

Now

FutureiRetrospective searching versus

current awareness

Retrospective searching

Current awareness

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iInformation retrieval: evolution of

storage and distribution media

• 1450 print

• 1975 + online access databases

• 1985 + CD-ROM

• 1990 + World-Wide Web (in Internet)

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Information retrieval: end user or intermediaries

End-user

Information intermediary(Broker or library or ...)

Information

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About “information”

Computer- and network-based information

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Information: from bits to meaningful information

Digitalcomputer data = bits

or01Program code, meaningful for andto be interpreted / executed bya suitable / compatible computer

Information = “documents”, meaningful for andto be interpreted byhuman beings

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Information: digitally stored and managed information

Categories of digital, computer readable information / data, forming electronic “documents”,understandable by human beings.

01textnumbersimagesvideosounds

multimedia

+

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01Digital information

Multimedia / Hypermedia

Information: types of digital information

Linear textHypertext

Static imagesVideo

Sound

Programs for computers

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Online / Networked

CD-ROM

Update speed

Volume

Some publication media compared

Printed

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The digital / electronic / virtual library

Structures & practices of physical libraries and archives

Communication capabilities of electronic networking

Computing

Digital /electronic / virtuallibrary

Digital /electronic / virtuallibrary

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Scientific publishing in Utopia: an ideal scheme

Many authorsMany authors

Many readers / usersMany readers / users

Many editors / publishersMany editors / publishers

Online remote access multimedia database serverOnline remote access multimedia database server

Many database search clients and user interfaces

Many database search clients and user interfacesone global ,

international computer data communication network

author = reader in science

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Indicate the differences between reality

and that simplified, ideal schemeof the information flow.

Indicate the differences between reality

and that simplified, ideal schemeof the information flow.

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Which basic problems hinder people to find information?

Which basic problems hinder people to find information?

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iInformation retrieval:

basic problems (Part 1)

• In many cases it is not completely clear to the user of an information retrieval system which information is in fact needed/required.

• In many cases the need for information cannot be expressed completely in the form of a query.

One of the reasons is that the complete context of the information need should ideally be expressed, including the knowledge and background of the searcher.

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• Language and vocabulary problems

»People use different languages and different terms (vocabularies) to describe a similar concept.

»The fluidity of concepts and vocabularies: meanings of terms depend on their context and may change over time.

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• Too many imperfect retrieval systems

»To retrieve and access the information which is in principle available, many different retrieval systems must be available and be mastered.

»Furthermore, a perfect information retrieval software does not exist.

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• Information overload

Users are often overwhelmed by the amount of available information and by the large influx of new information.

• The price (or inaccessibility) of particular information

A lot of information cannot be obtained or at least not free of charge.

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The information industry and the information market

The information industry and the information market

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The components of the information industry

The components of the information industry

• Authors

• Publishers

• Distributors

• Users

• Related organizations

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Online access from an institute to information: methods

Online access from an institute to information: methods

Online access from an institute to information on

• an external online computer host/server systems:

»supermarket model: select and pay for selected information only

»fixed price per year, payed by the institute to the information distributor

• a local server computer, maintained by the institute for their users

»for a fixed price per year, payed by the institute to the information distributor

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Increase in the number of scientific and technical serial publications

1

10

100

1000

10000

100000

1000000

1650 1700 1750 1800 1850 1900 1950 2000

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Evolution of information industry: measures

Evolution of information industry: measures

• Number of living databases.

• Number of database producers.

• Number of database vendors (including online services).

• Number of database records / documents.

• Number of online searches per year.

• ...

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The information market: growth in the database industry

The information market: growth in the database industry

0

2000

4000

6000

8000

10000

1975 1980 1985 1990 1995

Number oflivingdatabases

Number ofdatabaseproducers

Number ofvendors

Source: Williams, in: Gale Directory of Databases, 1998.Source: Williams, in: Gale Directory of Databases, 1998.

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The information industry / market: future trends (Part 1)


• Growth in the production of databases.

• Less analogue / hard-copy production = more digital production, storage, and distribution of information.

• More integration of information types into multimedia and hypermedia.

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• Growth in the number of

»producers and distributors,

»end-users searching databases due to easier use and lower costs of information technology

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Knowledge organisation: classifications, and thesaurus systems

Knowledge organisation: classifications, and thesaurus systems

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• Universal means here: covering all subjects

• Examples

»Universal Decimal Classification = UDC

used mainly outside U.S.A.

»Dewey Classification

used mainly in U.S.A.

»Library of Congress Classification

used mainly in U.S.A.

»...

Classification systems: examples of universal systems

Classification systems: examples of universal systems

Examples

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Thesaurus: descriptionThesaurus: 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

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Thesaurus relations

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

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Thesaurus systems covering all subjects: examples

Thesaurus systems covering all subjects: examples

• General systems / universal systems / on all subjects = broad and shallow, horizontal systems

• Examples:

»Library of Congress Subject Headings (LCSH)

»thesaurus systems built into word processing software

»...

Examples

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Try to find more suitable search terms to retrieve “general reviews about monitoring seawater pollution”

by using the thesaurus included in the program for word processing

that you use.

Limit yourself here to the concept of “pollution.”

Try to find more suitable search terms to retrieve “general reviews about monitoring seawater pollution”

by using the thesaurus included in the program for word processing

that you use.

Limit yourself here to the concept of “pollution.”

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Databases and computerised information retrieval

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What is a database?

A database is a collection of similar data records stored in a common file (or collection of files).

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Types of databases: examples

The databases that form the basis for

»catalogues of books or other types of documents

»computerised bibliographies

»address directories

»a full text newspaper, newsletter, magazine, journal+ collections of these

»WWW and Internet search engines

» intranet search engines

» ...

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iHints 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 right tools for each job (a suitable communication program for instance, in the case of online searches).

• Do not focus on a single source.

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• Consider citation indexes besides subject-oriented databases, as useful secondary information sources.

• Use the available tools for subject searching well.

• Try to cope with the language problems.

• Match your search strategy with the type of source.

• In computer-based retrieval systems, combine search terms when appropriate, using

»Boolean operators

»proximity operators (for instance “near”,...)

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• Work cost-effectively.

• Use special care when searching for names.

• Work iteratively.

• Keep a record of your work.

• Be critical: not all information is correct or useful.

• Stop searching when “enough is enough”

• Give up if necessary... (Not all questions have an answer.)

• ...

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iHints 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.

• Use synonyms, broader and related terms, if appropriate.

• Use narrower terms also, in most cases.

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Hints on how to use information sources: Boolean combinations (1)

In the case of computer-based information sources, use Boolean combinations of search terms when appropriate and when possible.

term x1OR term x2ORterm x3

term x1OR term x2ORterm x3

term y1OR term y2OR term y3

term y1OR term y2OR term y3

term z1OR term z2OR term z3

term z1OR term z2OR term z3

AND AND AND ...

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Hints on how to use information sources: Boolean combinations (2)

Most text search systems understand the basic Boolean operators typed in capital characters:

AND

OR

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How many (and which) concepts do you see in a search for

“general reviews about monitoring seawater pollution”?

How many (and which) concepts do you see in a search for

“general reviews about monitoring seawater pollution”?

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Prepare off-line, on paper, a suitable search query in a generic format, to find

“general reviews about monitoring seawater pollution” as the basis for later, concrete searches in databases.

(Limit yourself perhaps to 1 concept.)

Prepare off-line, on paper, a suitable search query in a generic format, to find

“general reviews about monitoring seawater pollution” as the basis for later, concrete searches in databases.

(Limit yourself perhaps to 1 concept.)

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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

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Hints on how to use information sources: work iteratively: example

When you search a database with subject keywords from a controlled list, added to each record:

1. Search with search terms that you know

2. Investigate the results and select good, relevant items

3. Look for the keywords added to these items

4. Select the good, relevant keywords

5. Formulate a new search with these keywords added

6. Execute the new search

7. Repeat the procedure

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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

payoffTime to stop?

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Computer networks, data communication and Internet

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Data communication: a definition

• Interpersonal communication

» Telecommunication

—Broadcast

—Telephone

—Data communication

–Remote login

–File transfer

–Hypertext transfer

–Electronic mail

–...

55

01Digital information

Multimedia / Hypermedia

Data communication: which ‘data’?

Linear textHypertext

Static imagesVideo

Sound

Programs for computers

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Data communication: applications (Part 1)

• Hard-copy transfer (Fax)

• Online use of the processing power of a remote computer

• Online access to information sources !

»library catalogues,

»bookshop catalogues,

»publisher’s catalogues,

»campus-wide and community information systems,

»(text or multimedia) databases,

»network-based journals, ...

57

Data communication: applications (Part 2)

• Software-downloading

• Electronic mail from a person to one or several persons

• Computer-network based interest groups

• Online talking / chatting (IRC,...)

• Video conferencing (Cu-seeme, ...)

• Selling, shopping, buying,..

• ...

58

Data communication: modems

• description: MODulator-DEModulator: device to convert digital data signals into a suitable form for transmission along a telecommunications channel, and to convert them back upon receipt into machine readable form.

• types

»(Acoustic coupler)

»Free standing box

»Board/card to plug-in microcomputer

59

Computer network protocols: definition

• When 2 computer systems communicate via network, they do that by exchanging messages.

• The structure of network messages varies from network to network.

• Thus the message structure in a particular network is agreed upon a priori and is described in a set of rules, each defined in a protocol.

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Data communication with a server in a Local Area Network

• (Terminal)

• Microcomputer with serial line communications software /terminal emulation software

• Microcomputer with network card and network software

Network Network serverserver

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Which applications do you know

of server computers in a LAN?

Which applications do you know

of server computers in a LAN?

62

Applications of server computers in a LAN

• Extra personal disk space for the users

• Common files with programs and/or data for many users (e.g. an intranet)

• Making files available from the institute to external users over the Internet (e.g. using ftp, gopher, WWW)

• Executing programs on the server (e.g. using Unix or Windows NT or Windows 2000, in multitasking / multiuser mode)

• Electronic mail servers; Usenet servers;...

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Do you have personal disk space available, through the LAN of your institute?

Do you have personal disk space available, through the LAN of your institute?

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National Wide Area Networks

• Public access national packet switching networks

• Research computer networks

• Public access made available by Internet Service Providers

• ...

65

National research computer networks: examples

• Belgium: BELNET

• Finland: FUNET

• Germany: DFN

• The Netherlands: Surfnet

• United Kingdom: JANET (Joint Academic Network)

• ...

Examples

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International computer networks: examples

• National public data communication networks linked together

• Internet

• FidoNet

• Bitnet / EARN

• Usenet

• ...

Examples

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What is the Internet? What is the Internet?

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@The Internet

data communications network (Part 1)

• “Internet” is not well-defined.

• A network of smaller networks:The global collection of interconnected local area, regional and wide-area (national backbone) networks which use the TCP/IP suite of data communication protocols.

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@The Internet

data communications network (Part 2)

• Links computers of various types.

• Is constantly growing.

• The analogy of a superhighway has been used to describe the emerging system of networked computers.

• The Internet has no owner, and is not managed by one organization.

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The Internet: access from your Local Area Network

Your microcomputer

Local Area Network (LAN)

One of the national networks

The global Internet

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@Data communication:

some services provided by Internet

Service Protocols used

• remote login telnet

• file transfer services ftp (or http)

• gopher menus to information space gopher

• hypertext transfer in WWW !! http

• WAIS or Z39.50 database searches WAIS, Z39.50

• electronic mail ! smtp, pop, imap,…

• Usenet News = Netnews nntp

• ...

72

@Host computers in the Internet:

definition

• A host (computer) is a domain name that has a unique IP address record associated with it.

• Could be any computer connected to the Internet by any means.

• For instance: www.vub.ac.be

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Internet data communicationlayers and protocols (Part 1)

different physical nets

IP = Internet protocol

TCP = host to host transfer control protocol

Application protocols:smtp, pop, imap, nntp, telnet, ftp, gopher, http, cu-seeme,...

Application programs

USER

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Client Server

Internet data communicationlayers and protocols (Part 2)

different physical nets

IP

TCP

Application protocols

Client application programs

Computer

USER

IP

TCP

Application protocols

Server application programs

Computer

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@Transmission Control Protocol /

Internet Protocol (TCP/IP)

• the main suite of transport protocols used on the Internet for connectivity and transmission of data across heterogeneous systems

• “glue that holds the Internet together”

• an open standard

• available on most Unix systems, VMS and other minicomputer systems, many mainframe and supercomputing systems and some microcomputer and PC systems

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@Internet: addresses of computers with the Domain Name System

• Internet style = Domain name system

• The Internet naming scheme consists of a hierarchical sequence of names from the most specific to the most general (left to right), separated by dots.

computer.subdomain.domain.(country if not USA) OR

n1.n2.n3.n4 where n is a natural number (8-bit)

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@Internet: growth in number of hosts

worldwide: linear plot

0

5000000

10000000

15000000

20000000

1993 1994 1995 1996 1997 1998January of each year

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@Internet Service Provider

= ISP

Internet Service Providers provides their clients access to Internet + in many cases

»software tools to start

»training

»technical support

»an accessible location for a WWW site of the client

»assistance with WWW site design and promotion

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Online communication: remote login and file transfer

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Remote terminal log-in / access: definition

The ability to access a computer from outside a building in which it is housed. This requires communications hardware, software, and actual physical links,although this can be as simple as common carrier (telephone) lines or as complex as telnet login to another computer across the Internet.

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Microcomputer -- external computer: some ways of data communication

Modem

External computer

Gateway computer system

Private/academic data comm. network (e.g. Internet)

Intern Extern

Local PAD

Leased, fixed communication line

Tele-phone

Micro-computer

Public data comm. network

Voice telecommunication network

LAN

TelePAD

ISDN

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Telnet: description

• The Internet standard protocol for remote terminal connection service; on top of the TCP/IP protocol suite

• Allows a user at one site to interact with a remote timesharing system at another site as if the user's terminal was connected directly to the remote computer

• Includes VT100 terminal emulation

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Data communication: downloading

The electronic transfer of information (whole file or fragments) from one computer to another, generally from a larger computer to a smaller one (such as from a server under Unix to a microcomputer).

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Data communication: downloading by copying a fragment

Capturing a small fragment of the information displayed:

1. select information on the display,

2. copy, and

3. paste in a document managed by another program.

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Data communication: file transfer

• Copying + downloading / transfer of a whole file

• Requires a transfer protocol with error correction

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ftp: file transfer protocol in the Internet

• A high-level protocol = application protocol in the Internet.

• For transferring files from one computer to another (free of errors).

• Provides the capability

»1. to connect to a remote computer,

»2. to execute a few simple tasks (such as listing the directory),

»3. to copy files to or from the remote computer quickly.

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World-Wide Web = WWW

WWW

88

WWW: example of a welcome page

Example


Indicate some difference between telnet and the World-Wide Web?

Indicate some difference between telnet and the World-Wide Web?

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URL = Universal Resource Locator

URL• = draft standard for specifying an object on the Internet

• the structure is in most casesprotocol://computer_address[/path_name/file_name]

• examples:

» telnet://biblio.vub.ac.be

»ftp://ftp.vub.ac.be/

»gopher://gopher.vub.ac.be/

»http://www.vub.ac.be/BIBLIO/index.html

»news:comp.infosystems.www

telnet://biblio.vub.ac.be/

telnet://biblio.vub.ac.be/

ftp://ftp.vub.ac.be/

ftp://ftp.vub.ac.be/

gopher://gopher.vub.ac.be/

gopher://gopher.vub.ac.be/

http://www.vub.ac.be/BIBLIO/index.html

http://www.vub.ac.be/BIBLIO/index.html

news:comp.infosystems.www

news:comp.infosystems.www

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URLformat / structure

URL1. The first part of a URL, before the colon “:”, specifies

the access method = protocol

2. The second part of the URL, after the colon “:”, is interpreted specific to the access method. In general, two slashes after the colon indicate a machine /computer name.


What is the difference between Internet and the World-Wide Web?

What is the difference between Internet and the World-Wide Web?

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WWW is an Internet application

Data communication

Internet

WWW

94

WWW

WWW: the essential elements

• Information delivery and access using hypertext/hypermedia documents/objects

»html documents

»http protocol: http clients http servers

• Integration of protocols in the Internet:

»http servers offering html documents including links to other http servers, telnet servers, ftp servers, nntp servers, gopher servers, ,...

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WWWComputer 1

WWW: hyperlinks

Hyperlinks can link a part of a hypermedia document to

• another part of the same document file

• another document file on the same server computer

• another document file on a server computer located elsewhere in the world

Computer 2

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WWW

WWW: hypertext mark-up language = HTML

• Hypertext mark-up language = HTML = the system of codes used by authors to build the hypertext-pages/files in WWW, for instance to create a title or an anchor.

• The codes are invisible / transparant for the user / reader.

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WWW

WWW: hypertext transfer protocol = HTTP

• Hypertext transfer protocol = HTTP = the software conventions used by client and server programs for WWW to request and transfer hypermedia documents.

• The protocol must not be known by he user / reader = the protocol is invisible / transparant for the user.

• Analogous with the telnet, ftp and gopher protocol.


Briefly compare TCP/IP and HTTP.

Briefly compare TCP/IP and HTTP.

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WWW

WWW: pages and forms

• Pages

Many documents developed for WWW are kept small and are named “pages”.

These often refer to several other “pages”.

• Forms = gateways to services and databases on server computers in WWW

Some pages contain electronic forms, to be filled in by the user.

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WWW

WWW: client / browse programs

• To access the WWW, you run a browser program.

• The browser reads documents, and can fetch documents from other sources. Information providers set up hypermedia servers which browsers can get documents from.

• The browser can display hypertext documents. Hypertext is text with pointers to other text. The browsers let you deal with the pointers in a transparent way: select the pointer, and you are presented with the text that is pointed to.

101

WWW

WWW: examples of browsers for your own computer

Browsers are available for many platforms; in particular: browsers for Windows + Winsock:

»Netscape Navigator and Communicator

»Microsoft Internet Explorer

»...

102

Netscape Navigator 4for Windows 95: screen shot

Example

103

MS Internet Explorer 4 for Windows 95: screen shot

Example

104


Which client program do YOU use or will YOU use

to access the WWW?

Which client program do YOU use or will YOU use

to access the WWW?

105


Browse the WWW, using an available

browser client program.

Browse the WWW, using an available

browser client program.

106


Visualise the HTML source code of a WWW page,

using a WWW client program.

Visualise the HTML source code of a WWW page,

using a WWW client program.

107


Exploit the possibility to open more than one window, using a WWW client program

in Windows.

Exploit the possibility to open more than one window, using a WWW client program

in Windows.

108


Why would you want to open more than one window

on WWW servers,using a WWW client program?

Why would you want to open more than one window

on WWW servers,using a WWW client program?

109

WWW

WWWapplications

Analogous to gopher applications:

• Access to online public access catalogues

• Campus-wide information systems

• Access to subject-oriented information

• Access to computer file archives

• Traveling / navigating through the Internet via linked html-pages

• Access to intranets within institutes / companies

110

WWW

WWW: How to save information from WWW?

Information displayed by your WWW browser/client program can be saved,

• by select, copy, paste in another document (and save)

• by saving a complete page to your disk

»in separate files (for instance 1 HTML file + some image files)

»in 1 file, using Microsoft Internet Explorer 5

• by copying the information into an e-mail message that you send to your own e-mail account

111


Copy some text fragment from WWWand paste it into another document

on your computer.

Copy some text fragment from WWWand paste it into another document

on your computer.

112


Save a text from WWW to disk, as HTML,

using a browser program.

Save a text from WWW to disk, as HTML,


113


Display an HTML file that you have saved

from the WWW to your disk,in a program for word processing.

Is the file displayed properly?

Display an HTML file that you have saved

from the WWW to your disk,in a program for word processing.

Is the file displayed properly?

114


Check if the program that you use can copy a picture from WWW,

so that you can directly paste it into a document

in another program on your PC.

Check if the program that you use can copy a picture from WWW,

so that you can directly paste it into a document

in another program on your PC.

115


Save a picture from WWW to disk,


Save a picture from WWW to disk,


116


Check if the program that you use for word processing

allows you to insert a picture that you saved saved to disk

into your word processing document.

Check if the program that you use for word processing

allows you to insert a picture that you saved saved to disk

into your word processing document.

117

WWW

WWW: How to save a HTML document including pictures?

Saving a complete HTML document including pictures can be done by using the appropriate software.

For instance:

»Microsoft Internet Explorer 4 with Frontpage Express

»Microsoft Internet Explorer 5

»Netscape Page Composer (included in the Netscape software suite)

118

WWW

WWW: growing number of WWW servers

0

1000000

2000000

3000000

4000000

5000000

6000000

7000000

1993 1994 1995 1996 1997 1998 1999 2000

119

Online access information sources and services

Introduction

120

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”, ...

121

Online access to information: avoid network traffic jams

To access from Europe online information sources in the US, work when lines are not saturated.

(better in the morning than in the afternoon)

122

Internet based information sources: problems

• too much of it / redundancy

• too few of some

• no order / no quality checks / no requirement to register new information offered

• constantly changing / increasing / growing

• authenticity?

123

Internet based information sources: how many? how much?

In 2000:

• about 1 000 million unique URLs in the total Internet

• about 10 terabyte (= 10 000 gigabyte) of text data

124

Types of online access information systems: “free” versus “fee”

Public access information sources free of charge

Fee-based online information services / Databanks

125


Internet-based encyclopedias

126

Encyclopedias accessible through Internet and WWW

Some encyclopedias and dictionaries are available through the WWW free of charge.

127

Encyclopedias accessible through Internet and WWW: examples

• Encyclopædia Britannica including Merrian Webster dictionary + links to selected WWW siteshttp://www.britannica.com/

• Encarta Concise Free Encyclopedia http://encarta.msn.com/

• A list of encyclopedia on the Internet:http://www.internetoracle.com/encyclop.htm

• Other lists of encyclopedia on Internet can be found as a part of browsable Internet directories.

Example

http://www.britannica.com/

http://www.britannica.com/

http://encarta.msn.com/

http://www.internetoracle.com/encyclop.htm



128


Internet directories and indexes

129

Internet: meta-information about Internet information sources

• in printed manuals and guides:

»not always possible to get a copy fast

»costs money to get a copy

»soon out of date

• offered on the WWW!:

»can become overloaded by too many simultaneous users

»cheaper to get a copy than in the case of printed material

» in most cases regularly updated

• (“intelligent agent” software on client PC)

130

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)

131

Internet global subject directories:introduction

• They are virtual libraries with open shelves, manually generated, man-made, for browsing.

• They cover only a small number of selected WWW sites.

• They are suitable mainly for broad, not very specific searches that are difficult to formulate in words.

• They can include an index on the contents of the directory (which may be confusing, as they are not real Internet indexes)

132

Internet global subject directories: Yahoo!

• A hypertext global subject directory can be found at http://www.yahoo.com/

and at many other sites, includinghttp://www.yahoo.co.uk/

• Entries are not rated.

• Yahoo! also offers access to an Internet index created by Inktomi, for searching with search statements, when the more limited directory of Yahoo! does not provide results.

• Accessible free of charge.

Example

http://www.yahoo.com/

http://www.yahoo.co.uk/

133


Try to find Internet sourceswhich are relevant for you,

by using an Internet subject directory.

Try to find Internet sourceswhich are relevant for you,

by using an Internet subject directory.

134

Internet local subject directories: examples in Belgium

• http://yellow.advalvas.be/weblist.html

• http://search.msn.be/exploring/exploring.asp

• The guide developed by the public libraries in Flanders: http://www.bib.vlaanderen.be/webwijzer

Examples

http://yellow.advalvas.be/weblist.html

http://yellow.advalvas.be/weblist.html

http://search.msn.be/exploring/exploring.asp

http://www.bib.vlaanderen.be/webwijzer

http://www.bib.vlaanderen.be/webwijzer

135

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 way than by only browsing/navigating.

• Each of these search systems is based on:

»a database of links to URLs, continuously collected from the Internet by a “robot” and incorporated in their big index, that is “machine-made”

»a search system with a user interface in a WWW form, to allow the user to search through that database

136

Internet indexes: scheme

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

137

Internet indexes:AltaVista

Example

The primary search interface can be found in the US:

http://www.altavista.digital.com/

http://www.altavista.com/

http://www.av.com/

(These addresses all lead to the same information.)

Mirror site in UK:

http://www.altavista.co.uk/

http://www.altavista.digital.com/


http://www.av.com/

http://www.av.com/

http://www.altavista.co.uk/

138

Internet indexes:AltaVista: features

• Allows full text searching

»of WWW, with a good coverage

»(of Usenet newsgroups archives)

• Allows advanced Boolean searching (in “Advanced” mode)

• Offers relevance ranking of search results

• Offers a link to an Internet subject directory (Looksmart)

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

Example

139


Read the online help, and search AltaVista

in simple search mode.

Read the online help, and search AltaVista

in simple search mode.

140


Read the online help offered by AltaVista

for its advanced search mode, and perform a Boolean search

with more than 1 concept using this advanced search mode.

Read the online help offered by AltaVista

for its advanced search mode, and perform a Boolean search

with more than 1 concept using this advanced search mode.

141


When should you better use the advanced search mode,

rather than just the simple one?

When should you better use the advanced search mode,

rather than just the simple one?

142

Internet indexes:AltaVista simple versus advanced

• “Simple” is suited for instance for searches

»with only 1 concept expressed as a series of synonyms, narrower terms,...such as a search for a person, a company, an institute,...

»when ranking is important

• “Advanced” is suited for instance for searches

»with more than 1 concept so that an AND combination is useful, besides an OR combination

»when ranking is not important

Example

143


Develop a suitable search query and apply this with AltaVista to find

“general reviews about monitoring seawater pollution”

Tips: use synonyms, narrower terms, truncation,

and Boolean combinations.

Develop a suitable search query and apply this with AltaVista to find

“general reviews about monitoring seawater pollution”

Tips: use synonyms, narrower terms, truncation,

and Boolean combinations.

144

Internet indexes: Northern Light

• The search interface can be found at http://www.northernlight.com/

• You can search

»free Web content and

»some other publications (full text articles) (but obtaining the text is not free of charge)

Example

http://www.northernlight.com/

145

Internet indexes: coverage / size of each index

The indexes grow and their “size ranking” is variable. In 1999:

1. AltaVista; Fast = All the Web; Northern Light

2. Google; Infoseek;... indexes based on the Inktomi database: Anzwers; Canada.com; Geocities; GoTo; Hotbot; MSN Web Search; Snap!; search system offered by Yahoo!, besides the index of the Yahoo directory;...

3. Excite; Lycos; Euroseek;...

4. Webcrawler;...

146


Try to find Internet sourceswhich are relevant for you, by using an Internet index.

Try to find Internet sourceswhich are relevant for you, by using an Internet index.

147

Internet information sources

Coverage of Internet directories and Internet indexes

A global Internet index

A global Internet directory

148

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 engines

• Gets information from directories and indexes

• Searching requires some skills and knowledge

• Good when even 1 index does not yield information

149

Finding multimedia files on the Internet: introduction

Several public access search systems are available free of charge to search the Internet for multimedia files:

»sound / audio files (music, speeches,...)

»images / pictures (either artwork, either photos, or both)

»video

150

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.

• The search results offer not only links, but also directly small versions of the images (= “thumbnails”)

151Examples

Finding images on the Internet:examples of image search engines

• http://www.altavista.com/ also audio and videochoose not the normal text search, but IMAGES in the user interface

• (http://ipix.yahoo.com/)

• http://scour.net/ (also audio and video)

• http://www.ditto.com/

• ...



http://ipix.yahoo.com/

http://ipix.yahoo.com/

http://scour.net/

http://scour.net/

http://www.ditto.com/

http://www.ditto.com/

152


Use a specialised search engineto find images

about a particular subject on the Internet.

Use a specialised search engineto find images

about a particular subject on the Internet.

153



Public access book databases

154

Public access book databases: an overview

Public access book databases: an overview

• (Databases by publishers.)

• Databases by book distributors / bookshops!

• Online public access library catalogues

• (Databases of computer-based versions of books.)

155

WWW

Examples of free public access bibliographic book databases (Part 1)

Examples of free public access bibliographic book databases (Part 1)

• Amazon.com (US):http://www.amazon.com/ http://www.amazon.co.uk/ note: amazon, NOT amazone

• Barnes and Noble (US):http://www.bn.com/

• Blackwell’s on the Internet (International):http://www.blackwell.co.uk/

Examples

http://www.amazon.com/

http://www.amazon.com/

http://www.amazon.co.uk/

http://www.bn.com/

http://www.bn.com/

http://www.blackwell.co.uk/

http://www.blackwell.co.uk/

156

!? Question !? Task !? Problem !?!? Question !? Task !? Problem !?

Search for titles of bookswhich are relevant for you,

using an online database provided by a book publisher or bookshop.

Search for titles of bookswhich are relevant for you,

using an online database provided by a book publisher or bookshop.

157



Online Public Access Catalogues = OPACs

158

Online access library catalogues:The British Library

Online access library catalogues:The British Library

• In 1997: http://opac97.bl.uk/

• Accessible online via WWW

• Access free of charge

Example

http://opac97.bl.uk/

159

Online access library catalogues:The British Library: screenshotOnline access library catalogues:The British Library: screenshot

Example

160



Fee-based online public access information services

161

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.U.S.A., Taiwan, UKSwitserlandU.S.A.U.S.A....

Name

America On LineOCLCOvid TechnologiesCompuserveCambridgeData-StarDialogEBSCO...

Examples

162



Location of the computer(s)

U.S.A.

U.S.A.U.S.A.U.S.A., The Netherlands,...Germany - U.S.A. - JapanThe Netherlands...

Name

Elsevier ScienceDirect ISI (Web of Science, JCR,…)MSN (Microsoft)ProdigySilverPlatterSTN Swets (e-journals)...

Examples

163

Online information services:total size of their databases

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 offers about 8 terabytes (= 8 000 gigabytes) of text data(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)

• Dialog offered about 9 terabytes (= 9 000 gigabytes) (in 1998)

»6 billion pages of text

»3 million images

164

Databases of online public access databases

Databases of online public access databases

• Examples

»I’M Guide = Information Market Guide

»Gale directory of databases !

• Their coverage

»online access databases

»(databases accessible on CD-ROM)

»...

165

Databases of databases: Gale

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 payed in advance

166



Online access databases about journal articles

167

Online access databases about journal articles: overview

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.

• Only few large databases offer access to bibliographies of articles published in journals, free of charge.

168

Online access databases about journal articles: Northern Light

Online access databases about journal articles: Northern Light

• Northern Light allows searching for

»WWW documents

»the full text of articles from many journals/magazines

• Searching is free of charge.

• Available from


http://www.nlsearch.com/

• Payment is required to receive the full text of an article.




169

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.


170




• Ingenta has acquired Uncover in 2000.

• Available from

• http://www.ingenta.co.uk/

• http://www.ingenta.com/

http://www.ingenta.co.uk/

http://www.ingenta.com/

http://www.ingenta.com/

171

Online access databases about journal articles: Article@INIST

Online access databases about journal articles: Article@INIST

• Article@INIST allows you to search in a bibliographic database, NOT full-text (Journal articles, Journal issues, Books, Reports or Conferences, doctoral dissertations) at the Institut de l'Information Scientifique et Technique, France.


• Available fromhttp://form.inist.fr/public/eng/conslt.htm


http://form.inist.fr/public/eng/conslt.htm

http://form.inist.fr/public/eng/conslt.htm

172

Online access databases about journal articles: Eric

Online access databases about journal articles: Eric

• Eric allows searching a bibliographic database of articles and other documents in the fields of information science and education

• Searching is free of charge

• Available fromhttp://ericir.syr.edu/Eric/

• Payment is required to receive the full text of a document.

http://ericir.syr.edu/Eric/

http://ericir.syr.edu/Eric/

173

Online access databases about journal articles: Medline

Online access databases about journal articles: Medline

• Medline allows searching a bibliographic database of articles in the field of medicine.

• free of charge

• available from many sites, including Ingenta

174

!? Question !? Task !? Problem !?!? Question !? Task !? Problem !?

Search for titles of journal articleswhich are relevant for you,

in a database provided free of charge.

Search for titles of journal articleswhich are relevant for you,

in a database provided free of charge.

175

Online access databases about journal articles: Web of Science

Online access databases about journal articles: Web of Science

• The Web of Science 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 instituts/companies that pay a yearly fee to the producer/publisher of the database.

• This database is not only suitable for subject searching, but also for citation searching.


When the Web of Science databaseis available to you:

use itfor subject searching,


use itfor subject searching,

177



Future trends

178

Online access information: future trends

Online access information: future trends

• Increasing amount of information available online.

• Increasing quality of server and client software.

• Increasing number of end-users searching for information online.

179

Citation searching

180


subject searching & citation searching

• Information retrieval is in most cases carried out in the form of searching for a particular subject/concept by using words and terms: subject searching

• A complementary method is searching for relevant documents among the documents cited in a known, identified, relevant, good “seed” document:citation searching

181


using citations

• Citations = references in publications to earlier work.

• Citations may lead to other, useful, relevant information:starting from a particular, interesting “seed” document,

»citations in that document may lead you to older relevant publications (+ snow-ball effect)

»citation indexes allow you to identify more recent publications which contain citations to that particular document

182

Information retrieval:using citations (scheme)

Time

NowSeed document

Snowball citation

searching

Citation

indexing

Past Future

183


citation indexes

Citation indexes are produced by the company I.S.I., the Institute for Scientific Information:

»Science Citation Index,

»Social Sciences Citation Index,

»Arts and Humanities Citation Index

»…

184

iInformation retrieval: publication

formats of citation indexes

• Printed

• On CD-ROM

»for use on a single microcomputer, or

»for implementation on a local network

• Online

» through online access information services

»all together as the Web of Science, implemented on many sites, accessible by all users of an institute/company that pays a fixed fee per year

185

Information retrieval: cited reference searching

An introduction to cited reference searching is offered through WWW by the Institute for Scientific Information:

186


For which kinds of subjects / research can citation searching

be particularly useful / appropriate?

For which kinds of subjects / research can citation searching

be particularly useful / appropriate?

187

iInformation retrieval: when is

citation searching appropriate?

Cited reference searching is

• appropriate mainly when you search journal articles that contain citations of a particular document or author, for instance to study the impact in science of particular ideas

»in that document or

»of that author(for instance in literature science)

• less appropriate when you search for papers on a more general subject



use itfor subject searching, and

for citation searching.


use itfor subject searching, and

for citation searching.

189

Document delivery and interlibrary lending

190

Document delivery: related activities and names

• Document delivery

• Document supply

• Interlibrary lending

• Information delivery

• Information supply

• Resource sharing

• Full text retrieval from external databases

• ...

191

Document delivery: some definitions

• Interlibrary lending = borrowing of books by a library to a requesting library

• Document delivery = Document supply = supply of copies of documents to a requesting person or institute, by libraries as well as by specialized, commercial centers

192

Document delivery: various actors

End-user / Person requesting an item

Institute and library of end-user

Intermediate institute

Library or document delivery service delivering the requested document

Direct delivery, endangering the existence of libraries

193

Document delivery: future trends

• Increasing number of requests for documents.

• Document supply centers supply scanned documents over the networks.

• Electronic journals

»Publishers store their documents on server computers and deliver electronically.

»Intermediaries (for instance traditional journal distributors) collect documents from editors and store documents on computer servers to provide access.

194

Evaluations in information retrieval

195

Evaluations in information retrieval:introduction

• The quality of the results, the outcome of any search using any retrieval system depends on many components / factors.

• These components can be evaluated and modified to increase the quality of the results more or less independently.

196

Evaluations in information retrieval:important factors

• The information retrieval system ( = contents + system)

• The user of the retrieval system and the search strategy applied to the system

Result of a searchResult of a search

197

Evaluations in information retrieval: the simple Boolean model

Boolean model: # items in database = # items selected + # items not selected

# Items selected =

# relevant items + # irrelevant items

Relevant Yes

1In

IrrelevantNo0

Out

198

Selecting relevant items

Dependent on the aims, independent of the search strategy

Selected and relevant!

Selectedbut not relevant

Not selected but relevant

Not selectedand not relevant

Dependent on the aims and dependent on the search strategy

199

Recall: definition and meaning

• Definition: # Of selected relevant items “Recall” = ------------------------------------------------- * 100% Total # of relevant items in database

• Aim: high recall

• Problem: in most practical cases, the total # of relevant items in a database cannot be measured.

200

Selecting relevant items: recall





201

Precision: definition and meaning

• Definition:

# Of selected relevant items“Precision” = --------------------------------------- * 100% Total # of selected items

• Aim: high precision

202

Selecting relevant items: precision





203

Relation between recall and precision of searches

100%

Recall

0 0 Precision 100%

Ideal = Impossibleto reach in most systems

Ideal = Impossibleto reach in most systems•

Search (results)

204

Recall and precision should be considered together

Examples:

• Increase in retrieved number of relevant items may be accompanied by an impractical decrease in precision.

• Precision of a search close to 100% may NOT be ideal, because the recall of the search may be too low. Make search / query broader to increase recall !

• Poor (low) precision is more noticeable than bad (low) recall.

205

Evaluation in the case of systems offering relevance ranking

• Many modern information retrieval systems offer output with relevance ranking.

• This is more complicated than simple Boolean retrieval, and the simple concepts of recall and precision cannot be applied.

• To compare retrieval systems or search strategies, decide to consider for comparison a particular number of items ranked highest in each output.This brings us to for instance: “first-20 precision”.

206


Give examples of retrieval systems that offer relevance ranking.

Give examples of retrieval systems that offer relevance ranking.

Documents

1 Internet en WWW voor het opsporen van wetenschappelijke informatie Paul Nieuwenhuysen Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussel [email protected]