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Information Architecture 2013 Ch 9 Metadata Many of the slides in this slideset are reproduced andor modified content from publically available ID: 287549

metadata data content thesauri data metadata thesauri content taxonomies amp terms umls thesaurus concepts practical related focus http faceted

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Slide1

IBE312: Information Architecture2013

. 9 –

Metadata

Many

the

slides in

this

slideset

are

reproduced

and/or

modified

content

from

publically

available

slidesets

Paul Jacobs (2012),

The

iSchool

, University of Maryland

http://terpconnect.umd.edu/~psjacobs/s12/INFM700s12.htm.

These materials were made available and

licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States

See

http://creativecommons.org/licenses/by-nc-sa/3.0/us/

for details.Slide2

Metadata

“Data about data” - Definitional and descriptive documentation/information about data…

From Free On-line Dictionary of Computing:

Data about data. In data processing, meta-data is definitional data that provides information about or documentation of other data managed within an application or environment.

For example, meta-data would document

data about data elements

or attributes, (name, size, data type, etc) and

data about records

or data structures (length, fields, columns, etc) and

data about data

(where it is located, how it is associated, ownership, etc.). Meta-data may include

descriptive information

about the context, quality and condition, or characteristics of the data.

(

Some other

definitions

.)Slide3

MetadataWhy do we need this?Types of metadataDescriptive/subjective/content (e.g. author, subject, keywords, …)

Administrative (e.g. owner, rights, cost, creation date, version, …)

Technical (e.g. format, size, dependencies, programs). . . .In practical terms:Metadata helps users locate, navigate, interpret contentMetadata helps organizations manage contentMetadata helps systems manipulate contentSlide4

Data without Metadata…

Who:

authored it? to contact about data?What: are contents of database?When: was it collected? processed? finalized? Where: was the study done?Why: was the data collected?How: were data collected?

processed? Verified?

… can be pretty useless!Slide5

Early Example of MetadataSlide6

Menagerie of TermsClassificationHierarchiesEpistemologyDirectoriesControlled vocabularies

Knowledge representation

Let’s focus on significant differences.Let’s focus on advantages/disadvantages.Let’s focus on how each is useful.Slide7

Controlled Vocabulary

Any defined subset of natural language

List of

equivalent terms

(synonym rings)

Use search logs.

List of

preferred terms

(authority files)

Commonly also include variant terms

Educating users, enabling

browsing

Term rotation (pointers in index)

p.201

Classification scheme / taxonomy

Hierarchical relationships

(narrower/broader)Slide8

Controlled Vocabulary

Queries

can be ”exploded” to increase recallSlide9

Controlled Vocabularyauthority file – inclusive

preferred term can serve as the unique identifier for a collection of terms, educate usersSlide10

Related Terms & TechniquesTaxonomiesAnything organized in some sort of hierarchical structureTagging

Adding almost any kind of metadata to content, but now often descriptive and user-provided

ThesauriFocus on relations between termsFocus on “concepts”OntologiesUsually model a specific domain or part of the worldGenerally machine-readableIncreasing complexity and richness

Metadata

Taxonomies

& Thesauri

Practical UsesSlide11

How are taxonomies, tagging, controlled vocabularies and thesauri used? The semantic gap:

What’s the problem

?Synonymy – roughly, different words or phrases can be used to express similar ideas (e.g. “notebook”, “laptop”)Polysemy – roughly, the same word can have different meanings (e.g., “line” (fishing, code, queue, . . .) )Taxonomies try to group similar concepts“Tags” often assign words to concepts, making it easier to find related conceptsControlled vocabularies avoid ambiguity (like a specific tag set)Thesauri represent attempts to better organize mappings between words and conceptsDo these present precision or recall problems?Slide12

TaxonomiesOrganization of objects according to some principleFamiliar examples:Linnaean taxonomy (for living organisms)

Web directories (e.g., Yahoo or ODP)

Corporate directoriesOrganization chartsOrganizational structures previously discussedMetadataTaxonomies & ThesauriPractical UsesSlide13

Tagging- e.g. Flickr – popular tags

Metadata

Taxonomies & ThesauriPractical UsesSlide14

Flickr – related tags

Metadata

Taxonomies & ThesauriPractical UsesSlide15

Del.icio.us – related tags

Metadata

Taxonomies & ThesauriPractical UsesSlide16

Thesauri: Motivation“Semantic gap” between concepts and words

Online

thesauri help mapping many synonyms or word variants onto one preferred term – improve precision in retrieval (p.203)Words are used to evoke conceptsConcrete objects: MacBook Pro, iPhoneAbstract ideas: freedom, peaceConceptsWords

Ideas

MeaningSlide17

Thesauri

Book of synonyms, often including related and contrasting words and antonyms.

In this class:

A controlled vocabulary in which equivalence, hierarchical, and associative relationships are identified for purposes of improved retrieval.

Technical lingo …

Thesauri standards: ISO 2788, …Slide18

Thesauri TypesSlide19

IA Uses of ThesauriFor organizationFor navigationFor indexing contentFor searchingSlide20

Applying IA PrinciplesFocus on users and user needs – users are different, and have different modelsFocus on content – concepts are different, too – different levels, words, complexity, vaguenessExamples:

What’s the difference between laptop, PDA, phone, and convergence device?

When is “cancer research” “oncology”?When a user browses a furniture catalog for chairs, do you show them ottomans and footstools?Slide21

Standard Thesaurus StructureComputer

Notebook

LaptopDesktopReplacement

Ultraportable

Tablet PC

IS-A

AKA

Synonyms (variants)

Narrower

Terms

Broader

Terms

PreferredSlide22

Semantic relationships in a thesaurus

(

pp. 204-205): Abbreviations: PT, VT, BT, NT, RT, Use (U) – VT use PT, Use For (UF) – full list of VT on the PT record, Scope Note (SN) – meaning of

the term to rule

out

ambiguity

.Slide23

Semantic relationships of a wine

thesaurus, p. 206Slide24

Some Real ExamplesContent tagging and social media (e.g. flickr, del.i.cious

)

Special-purpose classification schemes and thesauri (e.g. art & architecture thesaurus – AAT, UMLS)General semantic tools and classification schemes (e.g., Princeton WordNet, Roget’s Thesaurus)Slide25

Art & Architecture Thesaurus

Metadata

Taxonomies & ThesauriPractical Useshttp://www.getty.edu/research/conducting_research/vocabularies/aat/Slide26

UMLS (Unified Medical Labeling System)Source: National Library of Medicine (NIH)

Metathesaurus

Semantic

Network

SPECIALIST

Lexicon +Tools

135 broad

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