1

Finding information through the Internet and the WWW, in 2003:

a tutorial

Paul.Nieuwenhuysen@vub.ac.be

• Vrije Universiteit Brussel

• Information and Library Science, University of Antwerp

Belgium

Presented at the IADIS International Conference Internet / WWW 2003,

in Algarve, Portugal, 5-8 November 2003

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These slides will be available from

http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/

(note: BIBLIO and not biblio)

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• Basics of information.

• Fundamental difficulties in information retrieval, and how to take these into account.

• Thesaurus systems for better information retrieval.

- contents - summary - structure- overview

of this tutorial

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• Online access information sources and services (1)»types of information

sources»a systematic overview of

information sources and services that are accessible through the Internet:

»dictionaries and encyclopedias

»Internet subject directories for browsing

»Internet indexes for text searching

- contents - summary - structure- overview

of this tutorial

5• Online access information

sources and services (2)

»making better search queries with general thesaurus systems that are available free of charge

»meta-search systems

» the invisible web and how to exploit its contents, even though it is hidden away from text search systems

»finding images/pictures

- contents - summary - structure- overview

of this tutorial

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• Online access information sources and services (3)

»using image retrieval systems on the WWW to find relevant texts

»finding books

»finding journal articles

»fee-based databases

»using fee-based electronic journals

»open access electronic journals

- contents - summary - structure- overview

of this tutorial

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• Online access information sources and services (4)

»analyzing and exploiting citations (hyperlinks) on WWW pages to particular other known WWW pages.

- contents - summary - structure- overview

of this tutorial

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• How to evaluate queries and information retrieval systems?

• How to evaluate the quality of information sources?

- contents - summary - structure- overview

of this tutorial

9Is there a subject about which YOU personally

would like to learn more?

10-Interruptions-Questions

-Remarks -Discussions are welcome

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About “information”

Information concepts

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Information versus other products = bits versus atoms

• The essential difference between information and other economical products or natural products is that information on computers (such as databases) consists of bits (and bytes), while other economic / natural products (such as bananas) consist of atoms.

• This has many interrelated consequences.

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01010101101011010010

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Information: some strange properties (Part 1)

• Information is never consumed and does not deteriorate. However, nevertheless information becomes obsolete; speed of delivery can be crucial. The context is important.

• There is no agreed measure of a unit of information.

• The price of an information item is not well linked to its value in a particular situation. Moreover, one cannot well quantify the benefit/value of information.

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Information: some strange properties (Part 2)

• One information item can be available to different persons at the same time. Information can be well reproduced, which makes it cheap for wide consumption. However, copyright can keep the price high.

• Most digital information items (documents) can be changed, modified, falsified, manipulated… easier than physical products/items. “Is this document real, authentic, original?”

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Past

Now

Future

Retrospective searching versus current awareness: scheme

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Retrospective searching

Current awareness

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Retrospective searching versus current awareness: the basics

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• Searching for suitable information takes the form of retrospective searching mainly when we enter a new, unknown field or subject domain where we need supporting information.

• Once that we have found enough information, we need to keep aware of new information, because we are always challenged

»by the continuous flow of newly generated information and

»by the changing environment in which we work and live.

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About “information”

Computer- and network-based information

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?? Question ??

Which basic problems/difficulties hinder people

to find / access / use information?

Which basic problems/difficulties hinder people

to find / access / use information?

****

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Information retrieval: basic difficulties (Part 1)

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• 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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Information retrieval: basic difficulties (Part 2)

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• Computer systems are artificial, but nevertheless most use human language in their interface with the human users, for instance in database search systems. This may cause difficulties related to language and vocabulary in particular. Some examples:

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

• Concepts, vocabularies and meanings of words and terms may change over time.

• Meanings of words / terms may depend on their context.

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Information retrieval: basic difficulties (Part 3)

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• Many different and imperfect retrieval systems should or must be used.

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

»Furthermore, a perfect information retrieval software does not (yet) exist; scientific and technological evolution is fast in the domain of information retrieval software since about 1970.

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Information retrieval: basic difficulties (Part 4)

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• Information overload

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

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Information retrieval: basic difficulties (Part 5)

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• 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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Information retrieval: browsing and searching as methods

• To make information available, the producer of an information system can offer to the user basically two different ways for retrieval of the right information from the system:

»by browsing or navigating or

»by searching.

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• Browsing a logically ordered list of terms

• Logical order /Sorted by subject

• Table of contents

• Classification

• Hypertext-Hypermedia:jump from a page to a linked page

• Searching by submitting a search term to the system

• Alphabetical order / Not sorted by subject

• Alphabetical index

• Thesaurus

• Hypertext-Hypermedia: search built in a page

Information retrieval: browsing versus searching

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Information retrieval: examples of browsing systems

• Examples of browsing systems are

»a table of contents in the front part of a book,

»a set of books placed on shelves according to some classification system,

»a hypertext hierarchical directory on the WWW, or more generally all hypermedia systems.

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Information retrieval: examples of search systems

• Examples of search systems are

»the index (the register) in the back part of a book,

»a library or museum catalogue with a search interface,

»a search form on a web page.

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Databases and computerized information retrieval

Introduction

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Types of databases: examples

Examples: The databases that form the basis for

»catalogues of books or other types of documents

»computerized bibliographies

»address directories

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

»WWW and Internet search engines

» intranet search engines

» ...

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Information retrieval: the terminology

Several words are used with similar or related meanings:

»database / databank / corpus / collection / catalog / site / archive / file / web / ...

»contents of a database / records / documents / items / (web) pages / ...

»search / query / filter / ...

» thesaurus / controlled vocabulary / dictionary / lexicon / term bank / ontology / ...

»results / selection / retrieved documents / retrieved items / ...

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Comparison

Information retrieval: the basic processes in search systems

Information problem

Representation

Query Indexed documents

Representation

Retrieved, sorted documents

Text documents

Evaluation and

feedback

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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.

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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

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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 searchResult of a search

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Layered structure of a database

Database

(File)

Records

Fields

Characters

+ in many systems:relations / links

between records

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A simple database model: all records together form a database

The salami model = sliced bread model

»the salami or the bread is a “database”

»each slice of salami or bread is a “database record”

»there are no relations between slices / records

»the retrieval system tries to offer the appropriate slices / records to the user

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Characteristics / definition of structured text-information

• The text information is structured.(files, records, fields, sub-fields, links/relations among records,...)

• The length of records and fields can be “long”.

• Some fields are multi-valued = they occur more than once =repeated or repeatable fields

**--

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Structure of a bibliographic file

Record No. 1 Title Author 1: name + first name Author 2: ... Source Descriptor 1 Descriptor 2 ...

Record No. 2

Sub-fields

Repeated fields

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Databases and computerized information retrieval

Text retrieval and language

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Text retrieval and language: an overview

Text retrieval and language: an overview

Problems related to language / terminology occur1. even when the same language is used in searching and in the searched databases2. 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/orin the subject descriptors of the searched database(s)

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Text retrieval and language: enhancing retrieval

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.)

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Text retrieval and language: a word is not a concept (a)

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.

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Word

WordConcept

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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

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Text retrieval and language: a word is not a concept (a’’)

Text retrieval and language: a word is not a concept (a’’)

»synonyms!(such as scientific names besides common names)

»narrower terms, more specific terms (such as particular brand names);including terms with prefixes(for instance: not only viruses, but also retroviruses, rotaviruses...)

»spelling variations (such as UK English versus US English);possible variations after transliteration

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Text retrieval and language: a word is not a concept (a’’’)Text retrieval and language: a word is not a concept (a’’’)

»singular or plural forms of a noun (when this is used as a search term)

»(relevant) related terms

»various forms of a verb (when this is used in the query)

»broader terms (perhaps)

****

04/19/23

?? Question ??

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

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

**** 46

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Time flies like an arrow.

Fruit flies like a banana.

?

****Examples

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Time flies like an arrow.

Fruit flies like a banana.

****Examples

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Time flies like an arrow.

Fruit flies like a banana.

OK!

****Examples

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Text retrieval and language: ambiguity of meaning (a)

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.

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Text retrieval and language: ambiguity of meaning (a’)

Text retrieval and language: ambiguity of meaning (a’)

• Example of a word:

»Pascal the philosopher

»Pascal the computer language

****Example

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Text retrieval and language: ambiguity of meaning (a’’’)

Problem: Ambiguity of meaning

may be the cause of low precision.

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WordConcept

Concept

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Text retrieval and language: relation with recall and precision

Text retrieval and language: relation with recall and precision

Recapitulating the two problems discussed, we can say that

• Expansion of the query allows to increase the recall.

• Disambiguation of the query allows to increase the precision.

**--

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Text retrieval and language: phrases composed of words (a)Text retrieval and language:

phrases composed of words (a)

• Problem: Most retrieval systems can search for words, but they do not directly recognize or ‘know’ phrases / terms composed of more than 1 word.

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Text retrieval and language: phrases composed of words (b)Text retrieval and language:

phrases composed of words (b)

• Methods to solve the problem, provided by the computerized retrieval system:

»the user can and should indicate explicitly that a few words should be considered together by the retrieval system as forming a phrase/term(for instance in many Internet search engines by putting the phrase in quotes like “three word phrase”)

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Text retrieval and language: phrases composed of words (b’)

Text retrieval and language: phrases composed of words (b’)

»better: the retrieval system automatically recognizes a phrase/term relying on a term bank that has been created in advance;examples:the Internet search engines AltaVista and Scirus work in this way

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Natural language processing of the documents AND of the query

Comparison and matching of both

Enhanced text retrieval using natural language processing

Information problem

Representation

Query Indexed documents

Representation

Retrieved, sorted documents

Text documents

Evaluation and

feedback

**--

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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.

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Databases and computerized information retrieval

Hints on how to use information sources

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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

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Hints on how to use information sources: overview (Part 2)

• Match your search strategy with the type of source.

• Work cost-effectively.

• Use special care when searching for names.

• Be specific; avoid broad searches.

• Work iteratively.

• Keep a record of your work.

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

• Do not only focus on a single source.

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Hints on how to use information sources: overview (Part 3)

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

• Stop searching when “enough is enough”

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

• ...

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Hints on how to use information sources: overview (Part 4)

• In computer-based retrieval systems, consider applying

» truncation of search terms (*, ?...)

»combine search terms, using

—Boolean operators (OR; AND / +; NOT / AND NOT / -)

—proximity operators (for instance “NEAR”,...)

—phrase searching (“word1 word2”)

»searching limited to a field (for instance URL, title…)

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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.

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

Most text search systems understand the basic Boolean operators:

OR = obtain records that contain one or both search terms

AND = obtain records that contain both search terms

NOT= exclude records that contain a search term

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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:

OR

AND

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Hints on how to use information sources: Boolean combinations (3)

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

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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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?? Question ??

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

“general reviews about

monitoring seawater pollution that is due to effluentsin Tanzania”?

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

“general reviews about

monitoring seawater pollution that is due to effluentsin Tanzania”?

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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

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?? Question ??

What did you learn from the exercise

on the formulation of a query?

What did you learn from the exercise

on the formulation of a query?

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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.

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Results

Query Searching

Feedback

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Knowledge organisation: classifications, and thesaurus systems

Knowledge organisation: classifications, and thesaurus systems

Introduction

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• 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

Knowledge organisation: introduction

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• Various tools / systems / methods / approaches are available:

»Classification

»Taxonomy

»Thesaurus

»Ontology

»…

Knowledge organisation: some tools

Knowledge organisation: some tools

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Knowledge organisation: classifications, and thesaurus systems

Knowledge organisation: classifications, and thesaurus systems

Classifications

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• 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

Classification systems: examples of universal systems

****Examples

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Knowledge organisation: classifications, and thesaurus systems

Knowledge organisation: classifications, and thesaurus systems

Thesaurus systems

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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 applications related to information searching (1)

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.

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Thesaurus applications related to information searching (2)

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.

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Thesaurus applications related to information searching (3)

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).

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Thesaurus systems that cover all subjects

Thesaurus systems that cover all subjects

• General systems

• Universal systems

• Covering all subjects

• Broad and shallow systems

• Horizontal systems

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Thesaurus systems that cover all subjects: examples (Part 1)

Thesaurus systems that cover all subjects: examples (Part 1)

• Library of Congress Subject Headings (LCSH)

• thesaurus system built into word processing software

• thesaurus system that runs on a pc (independent of Internet) see for instance http://www.wordweb.co.uk/free/

***-Examples

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Thesaurus systems that cover all subjects: examples (Part 2)

Thesaurus systems that cover all subjects: examples (Part 2)

• thesaurus systems that can be used free of charge through the WWW

»http://education.yahoo.com/reference/thesaurus/index.html

»http://thesaurus.plumbdesign.com/ !

***-Examples

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General thesaurus system through the WWW: screenshot sea

**--Example

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General thesaurus system through the WWW: screenshot ocean

**--Example

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Thesaurus systems covering all subjects: comments

Thesaurus systems covering all subjects: comments

• An ideal, complete thesaurus that covers all subjects does not exist.

***-Examples

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Thesaurus systems focused on a particular subject

Thesaurus systems focused on a particular subject

• Focused on a particular subject domain = narrow and deep, vertical systems

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Thesaurus systems focused on a particular subject: examples

Thesaurus systems focused on a particular subject: examples

• ERIC: education, information science,...

• Psychological Abstracts / PsycInfo

• Sociological Abstracts / SocioFile

• INSPEC: physics, electronics, information technology

• the Aquatic Sciences and Fisheries Information System

• Medline (the Medical Subject Headings = MeSH)

• Various thesaurus systems for art and architecture can be found online: http://www.getty.edu/research/tools/vocabulary/

***-Examples

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Knowledge organisation: classifications, and thesaurus systems

Knowledge organisation: classifications, and thesaurus systems

Classification systems versus

thesaurus systems

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Knowledge organization:classifications versus thesauri

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)

****

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Online access information sources and services

Introduction

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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.

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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?

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Internet based information sources: problems / difficulties (Part 3)

• Change is the only constant: Information sources are constantly changing, growing, but sometimes disappearing.

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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.

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Internet based information sources: problems / difficulties (Part 5)

• Slow: The Internet is in many places and for many applications not yet fast enough.

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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.

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Internet based information sources: how many? how much information?

• More than 10 million WWW sites (in 2003)

• More than 2000 million (= 2 billion) unique URLs in the total Internet (in 2002)

• More than 10 terabyte (= 10 000 gigabyte) of text data (in 2001)

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Increasing number of online public access databases

Source: Gale Directory of Databases, 1997.Source: Gale Directory of Databases, 1997.

0

1000

2000

3000

4000

5000

6000

7000

1975 1980 1985 1990 1995 2000

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Online access information sources and services

Types of online access information systems

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

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Public access information sources free of charge

Fee-based online information services(NOT free of charge)

104**--

WWW sites classified by language

in 2003

other languages

50%

English50%

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Online access information sources and services

Dictionaries and encyclopedias accessible through the WWW

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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.

****

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Dictionaries accessible through Internet and the WWW: example

• The American Heritage® Dictionary of the English Language

»Over 200,000 entries, 70,000 audio word pronunciations, 900 full-page color illustrations

»Available free of charge from http://education.yahoo.com/reference/dictionary/

****Example

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Dictionaries accessible through Internet and the WWW: compilation

• A compilation/collection of dictionaries can be searched simultaneously and free of charge: http://www.onelook.com/

****Example

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Encyclopedias accessible through Internet and the WWW: examples

• Encarta Concise Free Encyclopedia 

»http://encarta.msn.com/

»Available in English and in some other languages

****Example

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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/

• Encyclopædia Britannica Concise

»http://education.yahoo.com/reference/encyclopedia/

****Example

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Encyclopedias accessible through Internet and the WWW: examples

• The Canadian Encyclopedia(in English and in French):

»http://thecanadianencyclopedia.com/

****Example

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Encyclopedias accessible through Internet and the WWW: overviews

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

• Other lists of encyclopedia on Internet can be found as a part of more general directories of Internet-based information sources.

****Example

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Online access information sources and services

Internet search functions built in browser software

***-

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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

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The Internet search button of browsers: introduction

Common graphical browsers provide a search function and a search button. Examples:

Netscape, Microsoft Internet Explorer

***-

116***-

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.

117***-

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.

118***-

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.

119***-

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.

120

Online access information sources and services

Internet directories and indexes

****

121

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)

****

122

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)

****

123

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!

****

124

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.

****

125

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.

126

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.

127

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.

• Accessible free of charge.

****Example

128

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.

• National Med/Peds Residents' Association - organization for residents, practioners and medical students interested in combined internal medicine and pediatrics.

• Neonatology Network - information and communication platform for neonatologists and pediatricians.

• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.

• Pediatric Critical Care

• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood illnesses.

• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10 2001.

• Pediatric Endoscopic Photos - illustrating intestinal problems in children.

***-Example

129

Internet global subject directories: Yahoo! for pediatrics

• Health > Medicine > Pediatrics:link to a digital library (health sciences) for young patients

***-Example

130

Internet global subject directories: Yahoo! to pediatrics organisations

• Health > Medicine > Pediatrics > Organizations:link to the American Academy of Pediatrics

***-Example

131

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.

• Michigan State University@

• Royal College of Paediatrics and Child Health - responsible for training, examinations, professional standards, and organisation of child health services for the UK.

• Tohoku University

• University of Alabama at Biringham - programs and training opportunities in pediatrics. Also contains faculy information and sub-speciatlty descriptions.

• …

***-Example

132

Internet global subject directories: Yahoo! Example: link to an e-journal

• Health > Medicine > Pediatrics >Journals: link to an electronic journal

**--Example

133

Internet global subject directories: Yahoo! Example: link to a directory

• Health > Medicine > Pediatrics >Web directories: link to a directory of sites on the WWW related to pediatrics

**--Example

134

Internet global subject directories: Yahoo! Example: link to a directory

• Health > Medicine > Pediatrics >Web directories: link to a directory of sites on the WWW related to pediatrics

**--Example

135

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.

***-Example

136

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

137

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

138

Internet global subject directories: Britannica

• A hypertext global subject directory can be found athttp://britannica.com/

• Entries are rated.

• Accessible free of charge.

• Combined and integrated with a great encyclopedia.

**--Example

139

Internet global subject directories: BUBL link

• A hypertext global subject directory to more than 10 000 WWW sites for the higher education community can be found athttp://bubl.ac.uk/link/

• Accessible free of charge.

**--Example

140

Internet global subject directories: Google directory

• A hypertext global subject directory can be found athttp://directory.google.com/

• Accessible free of charge.

• Based on the Netscape DMOZ Open Directory Project.

• Do not confuse this with the famous Google WWW search engine.

***-Example

141

Internet global subject directories: LookSmart

• A hypertext global subject directory can be found athttp://www.looksmart.com/

• Accessible free of charge.

**--Example

142

Internet global subject directories: Open Directory Project

• A hypertext global subject directory can be found athttp://www.dmoz.org/

• The contents is also used in other systems,such as Google Directory and Webbrain.

• Accessible free of charge.

***-Example

143

Internet global subject directories: Resource Discovery Network

• A collection of hypertext subject directories that focus on academic information sources can be found athttp://www.rdn.ac.uk/

• Together these lead to more than 30 000 selected WWW sites.

• Accessible free of charge.

***-Example

144

Internet global subject directories: Webbrain

• A hypertext subject directory can be found athttp://www.webbrain.com/

• Based on the Netscape DMOZ Open Directory Project.

• Uses more advanced techniques for the visualisation of the directory contents than DMOZ or Google.

• Accessible free of charge.

**--Example

145

Internet global subject directories: Webbrain: screenshot

**--Example

146

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?

***-

147

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?

***-

148

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?

***-

149

Internet global subject directories: evaluation criteria - desiderata (4)

• Are other services offered from the same site or with the same interface? Is the subject directory integrated with other services?Additional services can be

»an Internet index or a WWW index or a gateway to such an index for searching with a query

»weather, travel guides, flight and hotel reservations, maps,...

»WWW-based e-mail and e-mail address directories

»auctions through WWW

***-

150***-

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

151

Internet subject directories focusing on a specific subject domain: example

• A directory of sites on the WWW related to pediatrics

**--Example

152

Internet subject directories focusing on a specific subject domain (Part 1)

• Marine science and oceanography:

»http://oceanportal.org/ = http://ioc.unesco.org/oceanportal/

• Engineering, mathematics, computing:

»http://www.eevl.ac.uk/

»http://www.ub.lu.se/eel/

• Civil engineering:

»http://www.icivilengineer.com/

• Fishing:

»http://www.onefish.org/

***- Examples

        

153

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

• Medicine and healthcare: general:

• http://www.achoo.com/

• http://www.medmatrix.org/

• http://www.medscape.com/

• http://www.omni.ac.uk

• Medicine and healthcare: General pediatrics:

• http://GeneralPediatrics.com

• http://www.medscape.com/pediatricshome

• http://www.pedinfo.com/

***- Examples

        

154

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.

****

155

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

156

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

****

157

Internet indexes: building their database

***-

Inverted file, full text index,

register of the database

UserUser

Records derived from the input

and stored in the database

Internet documents fed into the database management system

Indexing

Retrieval

158

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.av.com/

»http://av.com/

• Mirror site in UK:

»http://uk.altavista.com/

»http://www.altavista.co.uk/

159

Internet indexes:AltaVista: features

• Allows full text searching of the WWW

• Offers relevance ranking of search results

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

• Offers a link to an Internet subject directory

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

***-

160

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 2003.

• Their most important competitor is Google.

**--

161

Internet indexes:All the Web

***-

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

• You can search the WWW and ftp servers.

• The database is one of the biggest.

• Not only HTML and plain text files, but also the full text of many Adobe PDF files is indexed.

• Offers also a module to search for pictures/images.

• Offers spelling suggestions in the search interface.

162

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 2003.

• Their most important competitor is Google.

**--

163

Internet indexes: Google (Part 1)

• http://www.google.com/

• Full-text searching is possible of many files that are available through the WWW.

• Not only HTML and plain text pages are covered, but also the first part is indexed of many files in other file formats, such as

»Adobe PDF,

»Microsoft Word, Microsoft Excel, Microsoft PowerPoint

»Rich Text Format…

****

164

Internet indexes: Google (Part 2)

• One of the most popular systems in 2001, 2002, 2003…

• For retrieval an algorithm is used that takes into account the links between WWW pages.A retrieved page is ranked higher when

»many sites/pages point to it

»“important” sites/pages point to it

• Another famous search system Netscape Search is based on Google (at least in 2003) http://search.netscape.com

****

165

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.

**--

166

Internet indexes: Google refers to a dictionary: display

**--Example

167

Internet indexes: from Google into a dictionary

**--Example

168

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.

***-

169

Internet indexes: from Google into a thesaurus

***-Example

170

Internet indexes: Google can expand a query: how?

***-

• If you want to retrieve more documents, then you can request Google to include synonyms of one or several of the words in your query in an automatic way.

• This works since 2003.

• You can do this by putting a tilde ~ in front the selected word.

• Example of a query: word1 ~word2 word3 word4

171

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.

172

Internet indexes: Google additional features

• Besides a system to search for WWW pages, Google offers also »a subject directory»searching for images/pictures on the WWW

»searching an archive of Usenet messages + posting to Usenet groups

»searching for news

• Thus Google has become a great integrator / aggregator.

****

173

Internet indexes:Google as a company

• The important competitors of Google are

»The Yahoo! subject directory system

»All the Web and AltaVista Internet search engines

• These are all owned by the same U.S. company, Yahoo!, since 2003.

**--

174

Internet indexes: Hotbot

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

• You can search the WWW.

• This system uses one of several of the famous, big Internet indexes that are created by other companies, to be selected by the user/searcher.

• Allows advanced, full Boolean searching.

**--Example

175

Internet indexes: Lycos

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

• Has been based on various databases of WWW pages over time.In 2001-2003: based on Alltheweb.

**--Example

176

Internet indexes: MSN Web Search

• Offered free of charge by Microsoft.

• You can search for WWW content.

• Since 1998.

• Famous system, because the search interface can be found with the search functions that have been built into one of the most widespread Internet browser, Microsoft Internet Explorer, and because it is offered by http://search.msn.com/

***-Example

177

Internet indexes: MSN Web Search

• Is based on an Internet index created by another company.But in 2003, Microsoft has started building its own WWW crawler.

**--Example

178

Internet indexes: Scirus

• Allows you to search for manually selected scientific information (only) on the WWW. This includes

» the peer-reviewed articles in the journals that are published in ScienceDirect by Elsevier, that can be downloaded in full-text format only when a fee has been paid to the publisher

»scientific open archives files, that contain scientific research articles that can be downloaded free of charge.

• The search interface: http://www.scirus.com

***-Example

179

Internet indexes: Scirus features

• Offered free of charge by Elsevier.

• Is partly based on the Fast WWW search system that is also used by Alltheweb.

• Offers access to information ordered according to some classification system / taxonomy.

• Offers not only access to files in html format, but also to files in PDF, PostScript and other formats.

***-Example

180

Internet indexes: Teoma

• Allows you to search for information on the WWW.

• Offers a feature that is not offered by most other search systems: categorization = classification = refinement = categorization = clustering of search results, to help the user coping with the problem of ambiguity of meaning of the search query that was made

• The search interface: http://www.teoma.com/

**--Example

181

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

182

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.

****

183

Internet indexes: coverage and size of each index

• Most indexes grow and their “size ranking” is variable.

• The biggest systems in 2003:

» Google !

» AltaVista

» All the Web (serving also Lycos)

» Systems based on the INKTOMI database of WWW pages.

****

184**--

Internet indexes: delay in indexing new pages

• The great, well known, international Internet indexes have a delay of more than 1 month in indexing new pages. (according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)

• So they are not suitable to search for rapidly changing recent information (such as “news”)(unless they index a small selection of important news sites more frequently.)

185**--

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/

186

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

**--

187

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

**--

188

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.

***-

189

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?

***-

190

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?

***-

191

Internet indexes: indexing + searching evaluation criteria - desiderata (2)

• Are the contents of meta-fields also indexed to make them searchable?

***-

192

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)

***-

193

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...

***-

194

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”

***-

195

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

***-

196

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?

***-

197

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

***-

198

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?

***-

199

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?

***-

200

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.

***-

201

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?

***-

202

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)?

***-

203

Internet indexes: output evaluation criteria - desiderata (5)

• Are results (retrieved documents) grouped / classified / categorized / clustered by the search system, on the basis of the subjects of the documents and are these presented as groups / clusters / classes / categories to the user of the search system, to assist the user in coping with the problems that can be caused for instance by multiple meanings of words used in a search query.

• Is translation of documents offered free of charge?

***-

204

Internet indexes: output evaluation criteria - desiderata (6)

• Is any fact extraction from the information sources offered, in an attempt to answer the query more directly than by offering only links to documents?

• Term suggestion: Does the system analyse the search results of the first query, to find frequently occurring terms and to suggest these to the user as new and potentially interesting additional query terms?

***-

205

Internet indexes: output evaluation criteria - desiderata (7)

• High stability and reliability?

• No large variations/fluctuations in the results from identical searches at different times.

• Relevance feedback:Can the user indicate among the search results of a first query the “good, relevant” and the “bad, irrelevant” results, so that the system can use this information to offer better results in a second query?

***-

206

Internet indexes: output evaluation criteria - desiderata (8)

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

***-

207

Internet indexes: help evaluation criteria - desiderata

• Good documentation and online help?

• Good help desk available?

***-

208

Internet indexes: current awareness evaluation criteria - desiderata

• Can the search system provide updated results, through electronic mail for instance, as a current awareness tool?

***-

209

Internet indexes: other services evaluation criteria - desiderata

• Other services available besides the normal WWW index:

» index to news resources, that is more frequently updated?!

»Internet subject directory?!

»anonymous ftp file index?

»gopher index?

»searchable Usenet newsgroups archive?

»white pages = people finder = addresses = ...

»WWW-based e-mail and e-mail address directories

»auctions through WWW

***-

210

?? 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?

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?

***-

211

Internet search systems: an overview of their relations

• Some relations among the most important public Internet search systems can be seen on a map in colours with hyperlinks, which is available from http://www.bruceclay.com/searchenginechart.pdf

• This map is kept up to date (at least up to 2002).

**--

212

Internet indexes for citation searching: introduction

• Some Internet indexes / search engines allow you to search for documents / pages / URLs that link to a particular page, to some URL that you already know (such as one of the web pages that you have developed or that you have made available yourself).

• Linking to a URL is similar to citing an information source.

• Such search systems can be used to analyse web citations.

• Web citations are sometimes named “sitations”, referring to the term “web site”.

**--

213

Internet indexes for citation searching: query syntax

• For details about the required query syntax, query formulation, see the online manual or help pages of the search system that you want to use.

• Take care to search for all variants such as

»//web-server-computer.country/website/index.html

»//web-server-computer.country/website/

»//web-server-computer.country/website

**--

214

Internet indexes for citation searching: link versus linkdomain

Do not confuse

• links to a particular web page,using for instance a query like “link:this_page.html” with

• links to a whole web domain, using for instance a query like “linkdomain: this_site”

**--

215

Internet indexes for citation searching: examples of systems

• AltaVista!

- Note that “Simple search” and “Advanced search” may give different results!?

+ Allows truncation, which can be used to search not only citations of a WWW page, but also of a whole WWW site.

+ Allows Boolean searching, which can be used to exclude self-citations.

• Google

• Lycos

**--Examples

216

Internet indexes for citation searching: applications

• Citation searching on the WWW or on an intranet can be used

»to get an idea of the importance, the fame, the impact of a particular web document, as measured by the number of links/citations to that page

»to find out who has considered a particular page as interesting enough to make a link to

»to find comments/criticisms on a particular web document

**--

217

?? 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?

***-

218

Internet indexes: Google limitations (Part 1)

• Google does NOT offer/allow

»an unlimited number of search terms in a search query

»manual or automatic truncation of words in a query

»manual or automatic stemming of words in a query

»full Boolean search formulations (OR, AND, brackets…) like in (sea OR ocean) AND (pollution OR contamination)

***-

219

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

***-

220

Internet indexes: Google limitations (Part 3)

• Google does NOT offer/allow

»powerful searching to find WWW documents that link to some document in a given WWW site (WWW site citation searching), as truncation is not possible in a Google query; only searching is possible to find documents that link to a particular WWW document; in other words, the URL of the WWW document as written in the query must be perfect and cannot be truncated(AltaVista is superior in this application, because it allows truncations in the search queries)

***-

221

Internet indexes: Google limitations (Part 4)

• 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

***-

222

Internet indexes: Google limitations (Part 5)

• Google does NOT offer/allow

»fact extraction from the information sources, in an attempt to answer the query more directly than by offering only links to documents

»a current awareness service, by email for instance(Googlealert exists however, a service independent of Google, but based on Google)

***-

223

Meta- search systems: scheme 1

User

Client computer

+WWW

client program

WWW server

computer

InternetWWW

WWW server

computerswith Internet

search systems

In Out

**--

224

Meta- search systems: scheme 2

UserClient

computer+

Multi-threaded Internet search client program

InternetWWW

WWW server

computerswith Internet

search systems

In Out

**--

225

Meta- search systems: scheme 1+2

User

Client computer

+WWW

client program

Client computer

+ Multi-threaded Internet search client program

WWW server

computer

InternetWWW

WWW server

computerswith Internet

search systems

In Out

**--

226**--

Meta- search systems: vocabulary

• “multi-threaded Internet search systems”

• “multiple search systems”

• “multi-search systems”

• “meta-search systems”

• “intelligent Internet search agents”

• “Internet meta-search tools”

• ...

227

Meta-search systems: server-based: scheme

**--

User

Client computer

+WWW

client program

WWW server

computer

InternetWWW

WWW server

computerswith Internet

search systems

In Out

228**--

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

229**--

Meta-search systems: server-based or client-based

• Online accessible on a server in the Internet.

• On the client, “meta-search software”.

230**--Examples

Meta-search systems: server-based systems

• http://www.all4one.com• http://www.bytesearch.com• http://www.cyber411.com• http://www.dogpile.com = http://dogpile.com/ • http://www.go2net.com = http://www.metacrawler.com• http://www.kartoo.com• http://www.mamma.com• http://www.profusion.com• http://www.search.com• http://www.vivisimo.com = http://vivisimo.com/

231**--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/

232**--Example

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

233**--Example

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

234**--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.

235**--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.

236**--Example

Meta-search systems: server-based: example: Dogpile

• The clustering software of Vivisimo is also used on other systems.

• Example: http://dogpile.com/

237**--Example

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

238**--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.

239

Meta-search systems: client-based: scheme

**--

UserClient

computer+

Multi-threaded Internet search client program

InternetWWW

WWW server

computerswith Internet

search systems

In Out

240**--Examples

Meta-search systems: client-based: example

Example:

• Copernic http://www.copernic.com

241**--

Meta-search systems: advantages (Part 1)

+ Saves time when otherwise more than only 1 Internet index would have to be used one after the other; for instance when searching for specific information that is hard to find in any single Internet index.

+ Some meta-search systems provide a useful integration of the results they get from the various primary search systems, with a removal of repeated results.

242**--

Meta-search systems: advantages (Part 2)

+ Some server-based and client-based meta-search systems show links among retrieved pages.

+ Some client-based meta-search systems allow storage on the client computer of a search query for later, repeated usage/application; application of such a system even allows excluding resulting documents that were already retrieved in an earlier search.

243**--

Meta-search systems: advantages (Part 3)

+ Can add value, for instance by analysing the results / hits so that they can be clustered / grouped / categorized / classified, to make further selections by the user / searcher easier and faster.Example: http://www.vivisimo.com

244**--

Meta-search systems: disadvantages (Part 1)

- It is not always clear through which Internet indexes the meta-search system will search.

- Not all meta-search systems can search all the major primary search systems; for instance Google is normally NOT included.

- The systems are often slower than a direct, primary search system.

- Only a limited number of the results that can be obtained from the various Internet indexes are shown.

245**--

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,

»...

246

Internet information sources

Coverage of Internet directories and Internet indexes

****

A global Internet index

A global Internet directory

247

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...)

248

?? Question ??

Which information on the Internet is not covered

by many searchable Internet indexes?

Which information on the Internet is not covered

by many searchable Internet indexes?

***-

249

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.

250

Internet

Internet indexes cover only a part of the Internet: scheme

***-

WWW

Databases and

file archives accessible through

the Internet

telnetftp...

telnetftp...

CGI, ASP,...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

Wordfiles

PDFfiles

251

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

***- Example

252

Internet indexes cover only a part of the Internet: conclusion for users

When you want to retrieve information about a particular subject from the Internet, use not only WWW indexes, but use also other sources accessible through the Internet

»databases! (book and journal bibliographies, library catalogues, archives of group messages, directories, atlases,…)

»rapidly changing information, such as news

» information accessible only when passwords are used

»anonymous ftp file archives

»e-mail based interest groups; Usenet newsgroups

***-

253

Internet indexes cover only a part of the Internet: conclusion for producers

When you want to distribute information on a global scale, through the Internet, realize that many potential users will not search your database(s), but only one of the global Internet indexes.

**--

254***-

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.invisible-web.net/

(See also other more general directories/overviews/lists of Internet information sources.)

255***-Example

Gateways to Internet databases accessible free of charge: invisibleweb

256***-

Hybrid systems to find information on the Internet

• Some systems require a search in words from the searcher, but they do not rely on classical Internet indexes.

• Example:

Ask Jeeves

257***-Example

Hybrid systems to find information on the Internet: Ask Jeeves

• Ask Jeeves tries to “answer questions” of searchers, by analysing the natural language queries and by referring to selected sources on the Internet.

• http://www.askjeeves.com/

• http://www.ask.com/

• http://www.aj.com/

258

?? Question ??

Do all Internet search tools support truncation in a query / search?

Explain your “yes” or “no”.

Do all Internet search tools support truncation in a query / search?

Explain your “yes” or “no”.

**--

259**--

Guides to searching the Internet that are available through WWW

• Searching the Internet: recommended sites and search techniques. [online]Available from: http://www.albany.edu/library/internet/search.html

• The RDN virtual training suite. [online] Available from: http://www.vts.rdn.ac.uk/ offers training for users with a specific academic or professional interest.

260

Internet: a hierarchy of tools to locate sources

• Meta-meta-information

• Meta-information

• Information and other sources

**--

• Meta-indexes = overviews = collections of Internet indexes

• Internet indexes of Internet sources

• Internet sources

261

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

****

262

?? Question ??

How can you easily find new pages that become accessible on the WWW

about a particular topic that is interesting for you?

How can you easily find new pages that become accessible on the WWW

about a particular topic that is interesting for you?

***-

263

?? Question ??

When you want to know if the contents of a particular WWW page

has changed, then you can of course

check/read/visit that page regularly.

But is there a simpler way to track changes?

When you want to know if the contents of a particular WWW page

has changed, then you can of course

check/read/visit that page regularly.

But is there a simpler way to track changes?

**--

264

Current awareness services focusing on WWW pages: introduction

• Tracking changes in one or more public access pages on the WWW or finding new pages, is possible in an automated way,

»by using one of the available, suitable, programs loaded on your client workstation! example: the advanced version of Copernic that is not available free of charge

» through “alert” services based on a server on the WWW

—that track updates for the user/subscriber

—and send alerts by email to the user/subscriber

***-

265

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.

***-

266

Current awareness services focusing on WWW pages: Google Alert

• Can discover relevant changed or new WWW pages for you in the future.

• Is based on the external Internet index Google.

• Works with search queries given by you that are stored on their server computer.

• Free of charge, at least up to 2003.

• http://www.googlealert.com/

***-Example

267

Current awareness services focusing on WWW pages: Google Alert

***-Example

268

Online access information sources and services

Online access information sources and services

Public access book databases

****

269

Public access book databases: introduction

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.

****

270

Public access book databases: an overview

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.)

****

271

Public access book databases: which one to use?

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.

****

272

Suitable book databases?

AIM RECOMMENDED 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

?

***-

273

Public access book databases by commercial producers

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).

****

274

Public access book databases provided by bookshops

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.

****

275

Book databases accessible free of charge: examples in U.S.A.

Book databases accessible free of charge: examples in U.S.A.

• Amazon.com (US):http://www.amazon.com/ http://www.amazon.co.uk/ note: amazon, NOT amazoneSubject description is poor.

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

****Examples

276

Book databases accessible free of charge: examples in Europe

Book databases accessible free of charge: examples in Europe

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

• VLB for books in Germanhttp://www.buchhandel.de/

• For books in Frenchhttp://www.chapitre.com

• Boeknet - De Nederlandse Internet Boekhandel (Dutch)http://www.boeknet.nl/

***-Examples

277

Book databases accessible free of charge: for old books

Book databases accessible free of charge: for old books

To find used, secondhand, rare, hard-to-find, and out-of-print books around the world:abebooks http://www.abebooks.com/

***-Examples

278

Free public access bibliographic book database + price comparisons

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.dealtime.com/

****

279

Example of an international public access dissertation database

Example of an international public access dissertation database

• The dissertation database of UMI is available from: http://wwwlib.umi.com/dissertations/

• The most current two years are available without charge.

***-Examples

280

Database of links to the full text of many books

Database of links to the full text of many books

• A database (accessible free of charge ) of links to the full text of many books:http://digital.library.upenn.edu/books/

**--Examples

281

Current awareness services for books

• Some systems can alert the user that a new book has been published when this fits the interest profile of the user.

• Such an interest profile can be stored on the server of the system in the form of

»keywords, or

»subject categories / subject fields

• Example: http://www.amazon.com

**--

282

Online Public Access Catalogues of libraries

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.

283

Online Public Access Catalogues = OPACs: definition

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

284

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.

***-

285

Online Public Access Catalogues:The British Library

Online Public Access Catalogues:The British Library

• Accessible online via WWW: Since 2000: http://blpc.bl.uk/

• Access free of charge

***-Example

286

Online Public Access Catalogues:catalogues of national libraries

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.

***-

287

Online Public Access Catalogues:union catalogues of libraries

Online Public Access Catalogues:union catalogues of libraries

• Some systems offer access to the merged catalogues of several libraries, so-called ‘union catalogues’.

• Example: Copac http://www.copac.ac.uk/ is accessible free of charge.

***-

288

Online Public Access Catalogues:simultaneous searching

Online Public Access Catalogues:simultaneous searching

• Some meta-search services allow simultaneous, parallel searching in one search action over several databases of libraries and bookdealers.

• The result depends on the availability and functionality of the target systems.

• + The coverage is very good.

• - Search options are rather limited.

**--

289

Online Public Access Catalogues:simultaneous searching: examplesOnline Public Access Catalogues:simultaneous searching: examples

• Infoball http://www.infoball.de

• Karlsruher Virtueller Katalog http://www.ubka.uni-karlsruhe.de/kvk.html

**--Examples

290

Public access book databases: evaluation criteria - desiderata (1)

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?

***-

291

Public access book databases: evaluation criteria - desiderata (2)

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?

***-

292

Public access book databases: evaluation criteria - desiderata (3)

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

***-

293

Public access book databases: evaluation criteria - desiderata (4)

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

***-

294

Public access book databases: evaluation criteria - desiderata (5)

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?

***-

295

Public access book databases: evaluation criteria - desiderata (6)

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?

***-

296

Public access book databases: evaluation criteria - desiderata (7)

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.)

***-

297

Public access book databases: evaluation criteria - desiderata (8)

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?

***-

298

Public access book databases: evaluation criteria - desiderata (9)

Public access book databases: evaluation criteria - desiderata (9)

• Are other services offered from the same site or with the same interface? Is the system integrated with other services?Additional services can be

»searchable databases of videos, of music CD’s, CD-ROMs, DVDs, all for sale also

»WWW-based e-mail and e-mail address directories

»auctions through WWW

**--

299

Public access book databases: evaluation criteria - desiderata (10)

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.

**--

300

Recommended book databases

AIM RECOMMENDED 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

***-

301

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.

***-

302

Online access information sources and services

Online access information sources and services

Fee-based online public access information services

****

303

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

• A lot of the information on the Internet is available free of charge, but another part is only accessible when a fee is paid to the producer and / or the distributor.

• The first commercial computer systems that make information available online were born around 1975. Most of them are now also available through the Internet.

• Some organisations pay these fees for some sources and then organise access, so that the members of the organisation can retrieve and exploit the information as if it is free of charge.

****

304

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)

305

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

306

Fee-based online access services: examples (Part 1)

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, UKSwitzerlandU.S.A.U.S.A.

Name

America On LineOCLCOvid TechnologiesCompuServeCambridgeData-StarDialogEBSCO

***-Examples

307

Fee-based online access services: examples (Part 2)

Fee-based online access services: examples (Part 2)

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 FactivaISI (Web of Knowledge, JCR,…)LexisNexisMSN (Microsoft)ProdigySilver PlatterSTN Swets-Blackwell (e-journals)...

***-Examples

308

Online information services: various names for similar systems

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

• ...

***-

309

Online information services: access methods

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: http://www.dialogweb.com; http://www.datastarweb.com)

• (Using client software dedicated to the particular service)

310

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 offered 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

****

311

Database hosts / distributors:evaluation criteria - desiderata (1)

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?

***-

312

Database hosts / distributors:evaluation criteria - desiderata (2)

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?

***-

313

Database hosts / distributors:evaluation criteria - desiderata (3)

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?

• ...

***-

314

Databases of online public access databases

Databases of online public access databases

• Example

»Gale directory of databases !

• Their coverage:

»online access databases

»(databases accessible on CD-ROM)

»...

***-

315

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 paid in advance

***-

316

Online use of external databanks: how to learn working with a host?Online use of external databanks: how to learn working with a host?

Ideally, combine all of the following:

»Using computer-assisted learning offered by the host organisation

»Attending demonstrations and courses offered by the host organisation

»Studying manuals offered by the host organisation

»Watching a video about online information searching

»Studying handbooks

»Online practicing!

**--

317

Online access information sources and services

Online access information sources and services

Online access databases about journal articles

****

318

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 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.

****

319

Online access databases about journal articles: Northern Light

Online access databases about journal articles: Northern Light

• Northern Light allows searching for the full text of articles from many journals/magazines.

• Searching is free of charge.

• Available from

»http://www.northernlight.com/

»http://www.nlsearch.com/

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

**--Example

320

Online access databases about journal articles: Ingenta (1)

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

321

Online access databases about journal articles: Ingenta (2)

Online access databases about journal articles: Ingenta (2)

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

• Ingenta has acquired Uncover in 2000.

• Available from

»http://www.ingenta.co.uk/

»http://www.ingenta.com/

***-Example

322

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, conferences, doctoral dissertations) at the Institut de l'Information Scientifique et Technique, France.

• Does not offer usage of classification or thesaurus.

• Searching is free of charge.

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

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

****Example

323

Online access databases about journal articles: Infotrieve

Online access databases about journal articles: Infotrieve

• Infotrieve allows you to search free of charge in a bibliographic database of the articles of more than 20 000 journal titles and conference proceedings, NOT full-text.

• Available from http://www3.infotrieve.com/

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

• Current awareness services are also offered free of charge: the table of contents of new issues of the journals that you have selected are sent to you by email.

***-Example

324

Online access databases about journal articles: Scirus

• This is a specialised Internet index that allows you to search for selected scientific information (only) on the WWW. This includes the peer-reviewed articles in the journals that are published in ScienceDirect by Elsevier.

• An article can be downloaded in full-text format only when a fee has been paid to the publisher

• The search interface: http://www.scirus.com

***-Example

325

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

326

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.

**--Example

327

Online access databases about journal articles: Medline

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

328

Online access databases:Web of Science

Online access databases:Web of Science

• The Web of Science (or more recently the Web of Knowledge) offers access through the WWW to a database of bibliographic descriptions of scientific journal articles in all subject domains.

• This database is (only) available to members of organisations / institutes / companies / consortia that pay a yearly, high fee to the producer/publisher of the database.

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

***-

329

?? Question ??

Which differences do you see between most of the commercial search systemsfor searching commercial databases,

and the freely accessible search systems to search for information

that is available free of charge through the Internet.

Which differences do you see between most of the commercial search systemsfor searching commercial databases,

and the freely accessible search systems to search for information

that is available free of charge through the Internet.

**--

330

Online access information sources and services

Online access information sources and services

Online information sources about journal titles

***-

331***-

Online information sources about journal titles: introduction

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

332***-Example

Online information sources about journal titles: example

Available free of charge:

• http://www.publist.com/ about classical journals

333

Online access information sources and services

Online access information sources and services

Electronic newsletters and journals

***-

334

Electronic newsletters and journals: introduction

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

335**--

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

336

Electronic newsletters and journals: various types and the price of accessElectronic 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

337

Electronic newsletters and journals: access and distribution methods

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

338

Electronic newsletters and journals through the WWW

Electronic newsletters and journals through the WWW

***-

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

339

Electronic newsletters and journals: example

***-Example

340**--

Electronic newsletters and journals: authentication

• To control access to fee based electronic journals some method for authentication and authorization is used by publishers or distributors:

»On the basis of the range of IP-addresses of the computer workstations used by the organisation

»On the basis of a username and password couple

—that are constant, permanent

—or that are changed often by the information provider

»Or based on a combination of those methods

341**--

Electronic newsletters and journals: authentication problems

• Up to now, the authentication methods are far from perfect:

»Authentication by IP-address gives problems with users on “external”, “unknown” workstations outside the simple IP-address range.

»Authentication by passwords is complicated and passwords cannot be kept secret.

342**--

Electronic newsletters and journals: the flow of information is hindered

• The free flow of scientific information is hindered by several related phenomena in traditional publishing:

»copyright of the publishers, so that copying and further distribution is forbidden,

»high prices to be paid to commercial publishers to access information,

»need to implement authentication + authorisation technology, as required by commercial publishers.

343**--

Electronic newsletters and journals: Open Archives Initiative OAI

• The free flow of scientific information is hindered by traditional distribution methods.

• As a reaction and as a partial solution, the Open Archives Initiative movement tries to develop and to implement alternative publishing methods that are based on publishing through computers and the Internet.

344***-

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?)

345**--

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)

346**--

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, such as SFX / OpenURL (commercialised by Ex Libris)

COMPLEXITY

347**--

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”.

348

!! Task - Assignment - Problem !!

Find out how you can efficiently access electronic journals

from your institute.

Find out how you can efficiently access electronic journals

from your institute.

***-

349**--

Electronic newsletters and journals: extensions of printed journals (Part 1)

• Electronic journals can provide text and graphics like printed journals, but also

»sounds

»animations, video, virtual reality / 3D, computer models

»computer programs

»hyperlinks to related documents and supplemental data; reference linking

»hyperlinks to corrections in the original article

»hyperlinks to databases

350**--

Electronic newsletters and journals: extensions of printed journals (Part 2)

• Presentation of the contents that can be adapted by the reader/user.

• Searching made possible through the full-text.

• Publishing articles without bundling in “numbers”.

• Making annotations / corrections available to all readers.

• Also their online “environment” may be interesting for the reader, with news, announcements, an alerting service, usage statistics, e-mail, a discussion forum and/or chatting among readers and authors, translation service, polls and surveys…

351**--

Electronic newsletters and journals: extensions of printed journals (Part 3)

• More details and examples can be found online: EJI(sm): A Registry of Innovative E-Journal Features, Functionalities, and Contenthttp://www.public.iastate.edu/~CYBERSTACKS/EJI.htm

352

Directory of Open Access Journals

• The Directory of Open Access Journals is a directory of electronic journals that can be accessed free of charge.

• Available since May 2003.

• http://www.doaj.org/

***-

353***-

Directory of Open Access Journals: screenshot

354**--

Specialised directories of online access

electronic journals• Several directories / catalogs / overviews / databases / lists

are available of electronic, computer-based, online accessible newsletters, newspapers, journals,... in particular subject domains.

• For example: a directory of journals in medicine accessible free of charge: http://www.freemedicaljournals.com/

355**--

Online access to electronic journals in developing countries

• The costs of access to scientific journals is high, while developing countries have few funds available.

• Therefore several initiatives have been taken to provide access at a lower price or free of charge to users in developing countries.

• An overview of such initiatives/projects/plans is available online through http://www.library.yale.edu/~llicense/develop.shtml

356

Online access information sources and services

Online access information sources and services

Finding multimedia files on the Internet

****

357****

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

358****

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”).

359**--

Finding images on the Internet:function

The systems to find images on the WWW function by searching for your search terms, for instance

• in the name of the file or in the path on the disk to the file that contains the image

• in the link leading to the image

• in the text nearby the image on a web page

• in the title of the web page that contains the image

• in the alternate HTML ALT tag text for the image (that may be present for users that apply a program for browsing that does not display graphics)

360****Examples

Finding images on the Internet:examples of search engines

• http://alltheweb.com/ !!

• http://gallery.yahoo.com/ !

• http://images.google.com/ !!! or through http://www.google.com/The largest database in this category (at least in 2002, 2003). For each result, not only a thumbnail is offered, but also directly the readable URL; this makes it easy to guess the relevance of the document.

361****Examples

Finding images on the Internet:examples of search engines

• http://multimedia.lycos.com/

• http://www.altavista.com/ !!(also audio and video, choose not the normal text search, but IMAGES in the user interface.)

362****Examples

Finding images on the Internet:examples of search engines

• http://www.ask.com/ or http://www.aj.com/ or http://aj.com/ Ask Jeeves.Offers no indication of the number of images retrieved, which is a disadvantage when many pictures are found, but only a few can be seen at the time.

• http://www.ditto.com/ !

363**** Examples

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

364**--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/

365**--Example

Finding audio on the Internet: example of a search engine

• http://www.findsounds.com

• Allows you to find sound files in formats aiff, au, wav.

366**--Example

Finding audio and video on the Internet: example of a search engine

• http://www.altavista.com/ (use the special multimedia finder)

367**--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/

368

Online access information sources and services

Online access information sources and services

Future trends

****

369

Online access information: future trends

• An increasing amount of information becomes available online.

• A growing amount of this online information becomes available free of charge.

• The quality of server and client software is growing.

A consequence is:

• An increasing number of end-users searching for information online.

****

370

Online access information: future trends regarding software

• Less usage of client software specific for one application, but increasing number of applications of generic, popular, widely distributed WWW client software.

• Increasing integration, interlinking of various types of information sources, servers, and client software.

**--

371

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.

****

372

Evaluations in information retrieval

****

373

Evaluations in information retrieval:summary

• The following gives an overview of approaches that are applied to assess the quality of

»information retrieval systems, and more concretely of search systems

»the resulting set of records obtained after performing a query in an information retrieval system

• Note: This should not be confused with assessing the quality and value of the content of an information source.

****

374

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.

****

375

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

376

Evaluations in information retrieval:why? (Part 1)

• To study the differences in outcome/results when a component of a retrieval system is changed, such as

»the user interface

»the retrieval algorithm

»addition by the database of uncontrolled, natural language keywords versus keywords selected from a more rigid, controlled vocabulary

****

377

Evaluations in information retrieval:why? (Part 2)

• To study the differences in outcome/results when a search strategy is changed.

• To study the differences in outcome/results when searches are performed by different groups of users, such as

»children versus adults

»inexperienced users versus more experienced, professional information intermediaries/professionals

****

378

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

****

379

Relevant items in a database: scheme

****

Dependent on the aims, independent of the search strategy

Relevant items!(In most cases the small subset)

Irrelevant / NOT relevant items(In most cases the large subset)

380

Selecting relevant items by searching a database: scheme

****

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

381

Recall: definition and meaning

****

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

• Aim: high recall

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

382

Selecting relevant items: recall

****

Selected and relevant!

Selectedbut not relevant

Not selected but relevant

Not selectedand not relevant

383

Recall: how to use the concept of recall

**--

Using the same database, variations in recall express the effect of search variations»Variations in search terms

»Use of a classification scheme

»Use of a thesaurus

»...

384

?? Question ??

How can you change your search strategy

to increase the recall?

How can you change your search strategy

to increase the recall?

***-

385

Precision: definition and meaning

****

• Definition:

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

• Aim: high precision

386

Selecting relevant items: precision

****

Selected and relevant!

Selectedbut not relevant

Not selected but relevant

Not selectedand not relevant

387

?? Question ??

How can you change your search strategy

to increase the precision?

How can you change your search strategy

to increase the precision?

***-

388

?? Question ??

When you change your search strategy to increase the precision,

which consequence do you expect for the recall, in most cases?

When you change your search strategy to increase the precision,

which consequence do you expect for the recall, in most cases?

***-

389

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)

****

390

?? Question ??

Indicate on the figure that a user improves a search.

Indicate on the figure that a user improves a search.

***-

391

?? Question ??

Indicate on the figure that a database producer

and / or the retrieval system improves the retrieval quality.

Indicate on the figure that a database producer

and / or the retrieval system improves the retrieval quality.

***-

392

?? Question ??

Indicate the relation between the recall and precision

in a classical information retrieval system in the form of a figure. Indicate in that figure

a good and a bad search.

Indicate the relation between the recall and precision

in a classical information retrieval system in the form of a figure. Indicate in that figure

a good and a bad search.

***-

393

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.

****

394

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”.

****

395

Evaluating the quality of information

Documentary information sources: evaluating their quality

****

396

Documentary information sources: evaluating their quality

• We should always be critical when using information sources, in view of

»the widely varying degrees of quality of information sources, and of

»the costs associated with searching, finding, using information.

****

04/19/23

?? Question ??

Which criteria do you know for the evaluation of

the quality of a documentary information source?

Which criteria do you know for the evaluation of

the quality of a documentary information source?

***- 397

398

Documentary information sources: evaluation criteria (1)

• Is the information valid, reliable, trustworthy, genuine, authentic? Is the author honest? Is the source objective, not subjective, without cultural or political or ideological or commercial bias? Is the origin an individual or a company or an organisation?Is the publication sponsored by some company or organisation?

***-

399

Documentary information sources: evaluation criteria (2)

• Is the information accurate, correct? Who is the author or producer? Has the source an author or a producer with a high expertise, a good reputation, good qualifications?Can the author be contacted for clarification or discussion? Was the information reviewed, edited, improved, corrected, censored, approved, verified, before publication? Do experts agree on the information provided?

***-

400

Documentary information sources: evaluation criteria (3)

• Is the information source unique? Does it offer a great amount of primary information, which is not obtainable from other sources?

• Is the information complete? Is the work available in its entirety?

• Does the source offer a wide coverage? Is the source comprehensive, substantive?

• Is the information current enough, up to date? Is a publication date provided?Is an expiration date provided?

***-

401

Documentary information sources: evaluation criteria (4)

• Does the document provide suitable references, so that you can verify statements and find older suitable information sources?

• Good clear format and lay-out of the information / User-friendly information system / Easy for users to orientate themselves within the resource and to find their way around it?

• Good user support / Good customer support?

• Is the type of distribution medium appropriate? (print, e-mail, online,...)

***-

402

Documentary information sources: evaluation criteria (5)

• Is the information what you want?If not, then reassess your needs and consider other types of information as well.

***-

403

Documentary information sources: evaluation criteria (6)

• Is the information suitable for your level of understanding of the subject? Is the document popular, suitable for the general public, for students, for professionals, for scholarly/academic use…?Does it report new, primary research (survey, experiment, observation, measurement, invention) or is it a review of sources published earlier?

• Does the information repeat or confirm what you already know, or is it complementary, contradictory, new?

***-

404

Evaluating the quality of information

Evaluating the quality of information

Computer-based information sources: evaluating their quality

***-

405

Computer-based information sources: evaluation criteria (Part 1)

***-

Besides more general criteria applicable to all information sources, for those sources that are based on computers and networks we see the following criteria:

• Easy to navigate?

»User-friendly information system?

»Easy for users to orientate themselves within the resource and to find their way around it?

»Is the resource organised into manageable chunks of information that can be browsed easily?

406

Computer-based information sources: evaluation criteria (Part 2)

***-

» Is a contents page or index offered that describes what is contained within the site?

» Are there good navigational links within the pages (e.g. 'back', 'forward', 'home')

» Are the links clearly labeled?

» Is the navigation process supported by images?

» Is there a single downloadable file for documents that exist as a series of separate pages?

» Is there a search facility within the resource?

407

Computer-based information sources: evaluation criteria (Part 3)

***-

• Good user support?

»Good support that is offered to users to help them answer queries and problems that arise whilst using the resource?

»Good computer-based, contextual help, documentation, training materials or tutorials?

»E-mail contact(s) and telephone number(s) available?

408

Computer-based information sources: evaluation criteria (Part 4)

***-

• Based on appropriate technologies?

»Are technologies and standards used that will enable users to access and utilize all aspects of the resource?

»Does the resource avoid that proprietary software should be used?

»Does the resource avoid the use of proprietary extensions to HTML, which some browsers will not be able to recognize?

409

Computer-based information sources: evaluation criteria (Part 5)

***-

»Does the format allow access to the resource for all users, even for instance sight impaired and those who can only navigate by using the keyboard?

• Information integrity / High stability of the contents / Low volatility of the contents?

»Is there adequate maintenance of the information content?

410

Computer-based information sources: evaluation criteria (Part 6)

***-

• System integrity?

»Site integrity relates to the stability of the site over time. This usually relates to the work of the site manager or web master.

»Realise that individual sites can be moved or withdrawn at any time by those responsible for publishing information on the Internet, and that addresses, file structures, formats and interfaces can be altered without warning.

»Is the site current and up to date?

411

Computer-based information sources: evaluation criteria (Part 7)

***-

» Is the site proven to be or expected to be durable in nature?

» Is the site adequately administered and maintained?

412

Computer-based information sources: The Internet Detective

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

**--

413

•These slides will be available through the WWW from http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/

•References to publications about this subject and more slides are available through the WWW fromhttp://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/

(note: BIBLIO and not biblio)

414

Questions?

Suggestions?

Topics for further discussion?