Transcript Lecture slides

Lifecycle Metadata for Digital
Objects (INF 389K)
September 18, 2006
The Big Metadata Picture, Web
Access, and the W3C Context
Anne Gilliland-Swetland, “Setting the
Stage” I: Generalities
Content: “library” focus on access
Context: “archives” focus on context of
creation and use
Structure: relationships among objects,
aggregations of objects, and versions of
objects
Note however: these three categories
can mix levels--how?
Setting the Stage II: Functional types
Administrative
Descriptive
Preservation
Technical
Use
Can you think of other types? Is this a
good breakdown? When does each
come into play? Who sees them?
Setting the Stage III:
Attributes
Source of metadata (internal or external)
Method of metadata creation (auto or
manual)
Nature of metadata (lay or expert)
Status (static/ long-term or dynamic/shortterm)
Structure (structured or unstructured)
Semantics (controlled or uncontrolled)
Level (item or collection or repository)
Setting the stage IV: Life Cycle
Creation and [multi-]versioning
(administration and description)
Organization (registration, cataloging,
indexing)
Searching and retrieval (transactions, system
records)
Utilization (rights, version control,
annotations)
Preservation and disposition (refresh, test
integrity, migrate, expunge…)
Gail Hodge, “Understanding
Metadata”
Definition: “Metadata is structured information that
describes, explains, locates, or otherwise makes it
easier to retrieve, use, or manage an information
resource.”
Purposes of metadata
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Resource discovery (surrogates, cataloging)
Organizing resources (statically or dynamically)
Interoperability (e.g., Z39.50 vs OAI)
Digital Identification (URL, PURL, DOI, Handle)
Archiving and preservation (e.g., PREMIS)
Understanding Metadata II:
Levels
FRBR distinctions:
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Work (a “creation of the mind”)
Expression (one of the possible ways that a
creation may be expressed)
Manifestation (one of the possible embodiments of
an expression)
Item (an individual exemplar of a manifestation)
Metadata can apply to objects at each of
these levels, although all levels may not apply
to all possible objects
Note this leaves out aggregates
Understanding Metadata III: Sets
Dublin Core (and extensions and profiles)
Text Encoding Initiative (TEI) header
Metadata Encoding and Transmission
Standard (METS)
Metadata Object Description Schema (MODS)
Encoded Archival Description (EAD)
Learning Object Metadata (LOM)
Visual Resources Association Core (and
CDWA)
MPEG multimedia
INDECS and ONIX
Understanding Metadata IV: Creation
and Interoperability
Templates, tools, harvesters
Metadata Registries
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PRONOM
GDFR
Crosswalks and frameworks (RDF,
Semantic Web)
Berners-Lee, “Web
architecture from 50,000 feet”
Universal information utility: how
Universal addresses: where (URIs)
Universal language: saywhat? (XML)
Action repositories: dowhat? (web services)
Description repositories: who/what (DTDs,
schemas, namespaces)
Logical structure for documents (RDF) makes
them operable-upon (at a high logical level:
B-L wants proofs, not just informal
gatherings)
XML in 10 Points
XML is for
structuring data
XML looks like HTML
(tags and attributes)
XML is text for
computers
XML is purposely
verbose
XML is a family
XML is only partly
new (SGML, HTML)
XHTML->XML
XML is modular
(namespaces)
XML is base for RDF,
Semantic Web
XML is free,
universal, supported
Eric Miller, “Introduction to
RDF”
XML provides syntax for RDF
RDF provides structural constraints and a
data model for metadata semantics
Means of publishing metadata semantics
Means of combining multiple metadata sets
developed for specific purposes
Goal: to enrich metadata available on the
Web and make search more precise
RDF Data Model
Resources (nodes)
Property-types (relations)
Values (assigned to nodes)
Triples in a directed graph
Can be iterative: each value can in turn be a
resource with property-type relations to
values
To ensure precision, each reference to a
specific semantic set is identified by
namespace
RDF and metadata
vocabularies (namespaces)
RDF/XML schema used for declaring
vocabularies (allowed “elements”) and
their allowed values (where restricted)
Each metadata set is maintained and
made available online via a URI
Metadata registries can gather the
metadata namespace definitions or
point to them
Tim O'Reilly
"What is Web 2.0?"
So what is it?
Web as platform/service
Harnessing collective intelligence (of users)
Data is the next “Intel Inside”: information as
value
End of the software release cycle: perpetual
beta, user collaboration
Lightweight programming models: cut and
paste, mashups
Software above the single device
Rich user experiences
Metadata and the Web (2.0?)
Metadata inside vs outside (but will we
seek help with preservation?)
Metadata as value-added (but who adds
the value?)
What metadata must be authoritative?
What metadata can never be
authoritative?
How important is metadata?