11/9/2000Information Organization and Retrieval Information Structures and Metadata University of California, Berkeley School of Information Management

11/9/2000 Information Organization and Retrieval

Information Structures and Metadata

University of California, Berkeley

School of Information Management and Systems

SIMS 202: Information Organization and Retrieval


Review

• Change of schedule… (Thesauri later)

• Metadata

• Controlled Vocabularies

• Dublin Core


Metadata• Metadata is:

– “data about data” (from Database)– Information about Information– Structures and Languages for the Description of

Information Resources and their elements (components or features)

– “Metadata is information on the organization of the data, the various data domains, and the relationship between them” (Baeza-Yates p. 142)


Type of Metadata systems and standards

• Naming and ID systems – URLs, ISBNs• Bibliographic description – MARC, Dublin Core,

TEI, etc.• Music -- SMDL• Images and objects – CIMI, VRA Core Categories• Numeric Data – DDI, SDSM• Geospatial Data – FGDC • Collections – EAD


Controlled Vocabularies

• Vocabulary control is the attempt to provide a standardized and consistent set of terms (such as subject headings, names, classifications, etc.) with the intent of aiding the searcher in finding information.


The problem

• Proliferation of the forms of names– Different names for the same person– Different people with the same names

• Examples – from Books in Print (semi-controlled but not

consistent)– ERIC author index (not controlled)


Conditions of Authorship?

• Single person or single corporate entity• Unknown or anonymous authors

– Fictitiously ascribed works

• Shared responsibility• Collections or editorially assembled works• Works of mixed responsibility (e.g.

translations)• Related Works


Name Authority Files ID:NAFL8057230 ST:p EL:n STH:a MS:c UIP:a TD:19910821174242 KRC:a NMU:a CRC:c UPN:a SBU:a SBC:a DID:n DF:05-14-80 RFE:a CSC: SRU:b SRT:n SRN:n TSS: TGA:? ROM:? MOD: VST:d 08-21-91 Other Versions: earlier 040 DLC$cDLC$dDLC$dOCoLC 053 PR6005.R517 100 10 Creasey, John 400 10 Cooke, M. E. 400 10 Cooke, Margaret,$d1908-1973 400 10 Cooper, Henry St. John,$d1908-1973 400 00 Credo,$d1908-1973 400 10 Fecamps, Elise 400 10 Gill, Patrick,$d1908-1973 400 10 Hope, Brian,$d1908-1973 400 10 Hughes, Colin,$d1908-1973 400 10 Marsden, James 400 10 Matheson, Rodney 400 10 Ranger, Ken 400 20 St. John, Henry,$d1908-1973 400 10 Wilde, Jimmy 500 10 $wnnnc$aAshe, Gordon,$d1908-1973

Different names for thesame person


Name Authority FilesID:NAFO9114111 ST:p EL:n STH:a MS:n UIP:a TD:19910817053048 KRC:a NMU:a CRC:c UPN:a SBU:a SBC:a DID:n DF:06-03-91 RFE:a CSC:c SRU:b SRT:n SRN:n TSS: TGA:? ROM:? MOD: VST:d 08-19-91 040 OCoLC$cOCoLC 100 10 Marric, J. J.,$d1908-1973 500 10 $wnnnc$aCreasey, John 663 Works by this author are entered under the name used in the item. For a listing of other names used by this author, search also under$bCrease y, John 670 OCLC 13441825: His Gideon's day, 1955$b(hdg.: Creasey, John; usage: J .J. Marric) 670 LC data base, 6/10/91$b(hdg.: Creasey, John; usage: J.J. Marric) 670 Pseuds. and nicknames dict., c1987$b(Creasey, John, 1908-1973; Britis h author; pseud.: Marric, J. J.)


Name authority filesID:NAFL8166762 ST:p EL:n STH:a MS:c UIP:a TD:19910604053124 KRC:a NMU:a CRC:c UPN:a SBU:a SBC:a DID:n DF:08-20-81 RFE:a CSC: SRU:b SRT:n SRN:n TSS: TGA:? ROM:? MOD: VST:d 06-06-91 Other Versions: earlier 040 DLC$cDLC$dDLC$dOCoLC 100 10 Butler, William Vivian,$d1927- 400 10 Butler, W. V.$q(William Vivian),$d1927- 400 10 Marric, J. J.,$d1927- 670 His The durable desperadoes, 1973. 670 His The young detective's handbook, c1981:$bt.p. (W.V. Butler) 670 His Gideon's way, 1986:$bCIP t.p. (William Vivian Butler writing as J .J. Marric)

Different people writing with the same name


Other Types of Controlled Vocabularies

• Gazetteers (Geographic Names)

• Code lists (e.g. LC Language Codes)

• Subject Heading Lists

• Classification Schemes

• Thesauri


Today

• SGML

• XML

• DTDs

• Document Markup

• Uses of XML


SGML & XML

• What is SGML/XML?

• Document Type Definitions

• Document Markup

• Sources and Resources


What is SGML/XML?

• A. SGML stands for Standard Generalized Markup Language– XML stands for eXtended Markup Language

• B. What it is NOT:– Not a visual document description– Not an application specific markup– Not proprietary


What is SGML/XML?• What it is:

– An international standard (SGML- ISO 8879:1986)

– A generic language for describing the structure of documents, and markup that can be used for those documents

– Intended for generating markup for content rather than form elements

• XML is a simplified subset of SGML (being established by W3C)


The Documents of Commerce• Customer Profiles• Vendor Profiles• Catalogs• Datasheets• Price Lists• Purchase Orders• Invoices• Inventory Reports

• Bill of Materials• Contracts• Credit Reports• Bank Statements• Proposals• Directories• Transportation Schedules• Receipts

Source Dr. Robert J Glushko


Alternatives for Exchanging Documents

Format

based

API

based

Publish information for a universalclient

Batch and high-volumeexchangebetween tradingpartners

Application Integration

HTML EDI CORBA / COM



Limitations of each Exchange Model

Format

based

API

based

Formattingmarkup “for eyes”

“Scrape and hope” integration

Must bepre-arranged

High cost

Rigid and inflexible

Pre-wired

Heavyweightto implement

Not native to the web

HTML EDI CORBA / COM



Having our Cake and Eating it TooWe need:

• the precision of APIs• the simplicity of HTML



XML to the Rescue (SGML-- and HTML++)

• Extensible Markup Language– a simplification of SGML, the Standard Generalized

Markup Language – instead of a fixed set of format-oriented tags like

HTML, XML allows you to create the schema -- whatever set of tags are needed --for your information type or application

– this makes any XML instance “self-describing” and easily understood by computers and people

• Version 1.0 ratified by W3C in 2/98; backed by Microsoft, Sun, Netscape, many others



Why XML is Revolutionary• XML enables a business to preserve any

“document type” or “database schema” when it publishes on the Web

• XML enables a business to send self-describing “business messages” that can be understood by programs, not just “by eye”

• This information cannot be encoded in HTML• XML-encoded information is smart enough to

support new classes of Web applications



XML Enables New Web Applications

• Data interchange between Web clients– use Web for application integration without

information loss (example: product information in supply chain, EDI)

• Moving processing from server to client– reduce network traffic and server load

(example: download airline schedule, find best flights without “back-and-forth” thrashing)



XML Enables New Web Applications

• Multiple client-side views of same data– expert and novice versions– manager and worker versions– localization (currency or measurement

conversions)• “Information push” from personalized

applications– selecting information based on user

preferences (example: custom news feed by matching article keywords against user profile)



The First Generation Web

Computers Browsers

.. making information accessible through browsers

scripts

HTML

Eyeballs onlyNo automationLimited integration



HTML Airline Schedule Seen “By Eye”

Airline Schedule Flight Information United Airlines #200 San Francisco 9:30 AM Honolulu 12:30 PM $368.50



HTML Airline Schedule Seen “By Computer”

<Title>Airline Schedule</Title><Body><H2>Flight Information</H2><H3>United Airlines #200</H3><UL><LI>San Francisco

<LI>9:30 AM<LI>Honolulu

<LI>12:30 PM <LI>$368.50 </UL></Body>



Next Generation Web

Java

Computers Computers

.. making information and services accessible to computers (and people)

XML

Structured searchesAgentsNew models



Airline Schedule in XML<TransportSchedule Type=“Airline”><Segment Id=“United Airlines #200”> <Origin>San Francisco</Origin><DepartTime>9:30 AM</DepartTime> <Destination>Honolulu</Destination><ArriveTime>12:30 PM</ArriveTime> <Price Currency=“USD”>368.50</Price></Segment></TransportSchedule>



XML is a Foundation for Interoperability

Format based

API based

WEB EDI CORBA / COM

XML

.. exchange information in an application and vendor neutral format



Industry Initiatives for Information Exchange

OBI Corporate Procurement AMEX, Wal-Mart, National Semi

OTP Retail Mastercard, Mondex

OFX Personal Finance Intuit, Microsoft

ECOM Computer Supply Chain Ingram + 24 largest channel players

HL/7 Health care HP, Major Hospitals, Insurance companies

All will use XML; this list will continue to grow …..



OM

G/ C

BO

HL

/7

ED

I-lite

OB

I

OT

P

SC

OR

OF

X

CIP

VC

I

Pin

nacles

ED

I-lite

OP

S

Go

ld

AP

I

IMS

ED

I X.12

ICE

Digital Anarchy - stovepipe protocols

•Narrowly defined

•Semantic Conflicts

•Time to Market/ Development costsSource Dr. Robert J Glushko


Open framework for commerce

Co

mp

uter

Au

tom

otiv

e

Pin

nacles

HL

/7

Common Business Language

Procure Retail

XM

L/ E

DIO

BI

OT

PSC

OR

OF

X

•Shared Semantics•Extensible and “aggressively interoperable”

Health Care

Office

Co

nsu

mer

Manufac-turing-

Supply Chain

Appliances



Shared Semantics for Time and Location

Shared semantics for location and time in all schemas that need them enables richer “commerce networks” of services:

<TransportSchedule Type=“Airline”> ...<Destination>Honolulu</Destination>

<Accommodation Type=“Hotel”>...<Destination>Honolulu</Destination>

<Event Type=“Concert”>…<Destination>Honolulu</Destination>



Automated Vacation Planning Service

• Book me the cheapest flight to Honolulu the first week of January

• Find a hotel room for the day I arrive

• What concerts are taking place the next day?



The Common Business Language• Specifies common semantics, common syntax,

and message packaging for information held by and exchanged among transaction partners and market participants

• These documents are the interfaces among the commerce components envisioned in the overall eCo architecture being realized in a current ATP project being carried out by CNgroup, CommerceNet, BusinessBots, and Tesserae

• CBL’s focus is on the functions and information that are common to all business domains



CBL and XML• CBL documents are described by XML

DTDs to make them “self-descriptive” and validatable

• CBL builds on existing standard or industry semantics where possible

• Complex descriptions and messages can be composed from primitives

• Domain-specific XML applications can be implemented in “native” form or as “hybrids” for maximal interoperability



Common Business Language Building BlocksCBL DocumentsCBL Documents

Business Forms

CatalogCatalog

Purchase OrderPurchase Order

InvoiceInvoice

Business Descriptions

VendorVendor

ServicesServices

ProductsProducts

Measurements

TimeTime

CurrencyCurrency

WeightWeight

Locale

AddressAddress

CountryCountry

LanguageLanguage

Classification

SICSIC

NAICSNAICS

FSCFSC

core

core

core

core

core



Common Business Language Building BlocksCBL DocumentsCBL Documents

Business Forms

CatalogCatalog

Purchase OrderPurchase Order

InvoiceInvoice

Business Descriptions

VendorVendor

ServicesServices

ProductsProducts

Measurements

TimeTime

CurrencyCurrency

WeightWeight

Locale

AddressAddress

CountryCountry

LanguageLanguage

Classification

SICSIC

NAICSNAICS

FSCFSC

core

core

core

core

core



SGML/XML Definitions

• Defining DTDs

• Markup


SGML/XML Structure

• An SGML document consists of three parts:– The SGML Declaration– The Document Type Definition (DTD)– The Document Instance

• An XML document REQUIRES only the document instance, but for effective processing a DTD is very important.


Document Type Definitions• The DTD describes the structural elements and

"shorthand" markup for a particular document type. It defines:– Names of "legal" elements– How many times elements can appear– The order of elements in a document– Whether markup can be omitted (SGML only)– Contents of elements (i.e., nested structures)– Attributes associated with elements– Names of "entities"– short-hand conventions for element tags. (SGML only)


DTD Components

• The major components of a DTD are:– Entity Declarations– Element Declarations– Attribute Declarations


Document Type Definitions• Entity Declarations are a "macro" definition facility for

both DTD and Document instance parts.– General Internal Entity Definitions

<!ENTITY name "substitute string">referenced by &name;

– General External Entity Definitions<!ENTITY name SYSTEM "file path">referenced by &name;

– Parameter Entity Definitions (used only inside DTDs)<!ENTITY %name "substitute string">or<!ENTITY %name SYSTEM "file path">referenced by %name; or %name


Document Type Definitions

• Element Declarations define the structural elements of a document and its associated markup.<!ELEMENT name - - content_model or declared_content +(include_list) -(exclude_list) >– Omitted tag minimization indicates whether

start-tags or end-tags can be omitted in the markup (o) or (-) are required in SGML but can NOT be used in XML


Document Type Definitions• Content model provides a nested structural

description of the elements that make up this element, e.g.:<!ELEMENT memo - - ((to & from), body, close?)><!ELEMENT body - O (p)* ><!ELEMENT p - O (#PCDATA | q)*<!ELEMENT q - - (#PCDATA)>...– ANY (in SGML) may be used to indicate a content

model of any elements in the DTD, in any order.



• Same Content model in XML<?xml version = “1.0”?><!DOCTYPE memo [<!ELEMENT memo ((to | from)+, body, close?)>

<!ELEMENT body (p)* ><!ELEMENT p (#PCDATA | q)* ><!ELEMENT q (#PCDATA)>…

]>– Note the XML Processing instruction “Prolog”– Note that & in previous page is not legal XML


Document Type Definitions• Declared content can be:

PCDATA, CDATA, RCDATA, EMPTY• Inclusion and Exclusion lists can be used to

indicate elements that can occur or are forbidden to occur in any sub-elements of the content model. (NOT in XML) E.g.:– <!ELEMENT memo -- ((to & from), body close?) +(fn)>

– says that element fn can appear anyplace in the memo.



• Attribute Declarations define attributes associated with (potentially) each element of a document and provide the acceptable values for those attributes.


Attributes Example• <!ATTLIST associate_element attribute_name declared_value

default_value >• <!ATTLIST memo status (PUBLIC | CONFIDENTIAL)

PUBLIC>– In markup of a document:

<memo status="CONFIDENTIAL">also, because of the default set:<memo>would be the same as <memo status="PUBLIC">There are a variety of special defaults and data types that can be given in attribute definitions


Sample SGML DTD<!doctype ELIB-TEXTS [



<!ELEMENT ELIB-TEXTS o o (ELIB-BIB*)>

<!ELEMENT ELIB-BIB - - (BIB-VERSION, ID, ENTRY?, DATE?, TITLE*, ORGANIZATION*,(SERIES | TYPE | REVISION | REVISION-DATE |AUTHOR-PERSONAL | AUTHOR-INSTITUTIONAL | AUTHOR-CONTRIBUTING-PERSONAL |AUTHOR-CONTRIBUTING-PERSONAL | AUTHOR-CONTRIBUTING-INSTITUTIONAL | CONTACTAUTHOR | PROJECT | PAGES | BIOREGION | CERES-BIOREGION | TEXTSOUP | LOCATION |ULTIMATE-CLIENT | URL |KEYWORDS | NOTES | ABSTRACT)*, (TEXT-REF | PAGED-REF)* )>



<!ELEMENT ID - o (#PCDATA)><!ELEMENT ABSTRACT - o (#PCDATA)><!ELEMENT AUTHOR-CONTRIBUTING-INSTITUTIONAL - o (#PCDATA)><!ELEMENT AUTHOR-CONTRIBUTING-PERSONAL - o (#PCDATA)><!ELEMENT AUTHOR-PERSONAL-CONTRIBUTING - o (#PCDATA)>… etc… ]>


XML version<!doctype ELIB-TEXTS [



<!ELEMENT ELIB-TEXTS(ELIB-BIB*)>

<!ELEMENT ELIB-BIB (BIB-VERSION, ID, ENTRY?, DATE?, TITLE*, ORGANIZATION*,(SERIES | TYPE | REVISION | REVISION-DATE |AUTHOR-PERSONAL | AUTHOR-INSTITUTIONAL | AUTHOR-CONTRIBUTING-PERSONAL |AUTHOR-CONTRIBUTING-PERSONAL | AUTHOR-CONTRIBUTING-INSTITUTIONAL | CONTACTAUTHOR | PROJECT | PAGES | BIOREGION | CERES-BIOREGION | TEXTSOUP | LOCATION |ULTIMATE-CLIENT | URL |KEYWORDS | NOTES | ABSTRACT)*, (TEXT-REF | PAGED-REF)* )>



<!ELEMENT ID (#PCDATA)><!ELEMENT ABSTRACT (#PCDATA)><!ELEMENT AUTHOR-CONTRIBUTING-INSTITUTIONAL (#PCDATA)><!ELEMENT AUTHOR-CONTRIBUTING-PERSONAL (#PCDATA)><!ELEMENT AUTHOR-PERSONAL-CONTRIBUTING (#PCDATA)>… etc… ]>


Document Using That DTD<ELIB-BIB><BIB-VERSION>ELIB-v1.0 </BIB-VERSION><ID>6</ID><ENTRY>February 13 1995</ENTRY><DATE>March 1, 1993</DATE><TITLE>Water Conditions in California Report 2</TITLE><ORGANIZATION>California Department of Water Resources</ORGANIZATION><SERIES>120-93</SERIES><TYPE>bulletin</TYPE><AUTHOR-INSTITUTIONAL>California Department of Water Resources </AUTHOR-INSTITUTIONAL><PAGES>17</PAGES><TEXT-REF>/elib/data/disk/disk5/documents/6/HYPEROCR/hyperocr.html </TEXT-REF><PAGED-REF>/elib/data/disk/disk5/documents/6/OCR-ASCII-NOZONE </PAGED-REF></ELIB-BIB>


A More Complex DTD<!DOCTYPE USMARC [<!ELEMENT USMARC - - (Leader, Directry, VarFlds)><!ATTLIST USMARC Material (BK|AM|CF|MP|MU|VM|SE) "BK" id CDATA #IMPLIED>

<!ELEMENT Leader - O (LRL, RecStat, RecType, BibLevel, UCP, IndCount, SFCount, BaseAddr, EncLevel, DscCatFm, LinkRec, EntryMap)><!ELEMENT Directry - O (#PCDATA)><!ELEMENT VarFlds - O (VarCFlds, VarDFlds)>

<!ELEMENT LRL - O (#PCDATA)>…etc…


More complex DTD (cont.)<!ELEMENT VarDFlds - O (NumbCode, MainEnty?, Titles, EdImprnt?, PhysDesc?, Series?, Notes?, SubjAccs?, AddEnty?, LinkEnty?, SAddEnty?, HoldAltG?, Fld9XX?)>

<!ELEMENT NumbCode - O (Fld010?, Fld011?, Fld015?, Fld017*, Fld018?,

Fld019*, Fld020*, Fld022*, Fld023*, Fld024*, Fld025*, Fld027*,

Fld028*, Fld029*, Fld030*, Fld032*, Fld033*, Fld034*, Fld035*, Fld036?, Fld037*, Fld039*, Fld040?, Fld041?, Fld042?, Fld043?, Fld044?, Fld045?, Fld046?, Fld047?, Fld048*, Fld050*, Fld051*, Fld052*, Fld055*, Fld060*, Fld061*, Fld066?, Fld069*, Fld070*, Fld071*, Fld072*, Fld074*, Fld080?, Fld082*,

Fld084*, Fld086*, Fld088*, Fld090*, Fld096*)>

<!ELEMENT MainEnty - O (Fld100?, Fld110?, Fld111?, Fld130?)>

<!ELEMENT Titles - O (Fld210?, Fld211*, Fld212*, Fld214*, Fld222*,

Fld240?, Fld242*, Fld243?, Fld245, Fld246*, Fld247*)>

<!ELEMENT EdImprnt - O (Fld250?, Fld254?, Fld255*, Fld256?, Fld257?, Fld260?, Fld261?, Fld262?, Fld263?, Fld265?)>

<!ELEMENT PhysDesc - O (Fld300*, Fld305*, Fld306?, Fld310?, Fld315?,

Fld321*, Fld340*, Fld350?, Fld351*,Fld355*, Fld357*, Fld362*)>

…etc…


Complex DTD (cont.)

<!ELEMENT Fld245 - O (Six?, (a|b|c|f|g|h|k|n|p|s)+)><!ATTLIST Fld245 AddEnty (No|Yes|Blank) #IMPLIED NFChars (0|1|2|3|4|5|6|7|8|9|Blnk) #IMPLIED>

…etc…

<!ELEMENT a - O (#PCDATA)><!ELEMENT b - O (#PCDATA)><!ELEMENT c - O (#PCDATA)><!ELEMENT d - O (#PCDATA)>

<!ELEMENT e - O (#PCDATA)>


Document Markup• All document markup is derived from the DTD for the

particular document type.• The DTD must be referenced in the document using

the DOCTYPE declaration:– <!DOCTYPE name SYSTEM "file_path" >

or<!DOCTYPE name SYSTEM "file_path" [doctype_declaration_subset]>or<!DOCTYPE name [doctype_declaration_subset]>The doctype_declaration_subset can be any combination of elements, entity, and attribute declarations.


XML-Data

• Proposal to W3C for a “schema language” based on XML for describing a large variety of metadata descriptions and structures

• More generally -- as seen in the SGML examples previously -- XML can be used as a record description language for metadata records.


HTML

• HTML was not originally "real" SGML, the DTD was invented after the language.

• It is often more concerned with the form of the output on the screen than with the structural contents of the HTML docs.

• Relies on the application (such as Netscape) to implement interesting actions like hypertext linking.


How can you describe an information-bearing object?


Dublin Core

• Review…

• Simple metadata for describing internet resources.

• For “Document-Like Objects”

• 15 Elements.


Dublin Core Elements

• Title• Creator• Subject• Description• Publisher• Other Contributors• Date• Resource Type

• Format• Resource Identifier• Source• Language• Relation• Coverage• Rights Management


Title

• Label: TITLE

• The name given to the resource by the CREATOR or PUBLISHER.


Author or Creator

• Label: CREATOR

• The person(s) or organization(s) primarily responsible for the intellectual content of the resource. For example, authors in the case of written documents, artists, photographers, or illustrators in the case of visual resources.


Subject and Keywords

• Label: SUBJECT • The topic of the resource, or keywords or phrases that

describe the subject or content of the resource. The intent of the specification of this element is to promote the use of controlled vocabularies and keywords. This element might well include scheme-qualified classification data (for example, Library of Congress Classification Numbers or Dewey Decimal numbers) or scheme-qualified controlled vocabularies (such as MEdical Subject Headings or Art

and Architecture Thesaurus descriptors) as well.


Description

• Label: DESCRIPTION • A textual description of the content of the resource,

including abstracts in the case of document-like objects or content descriptions in the case of visual resources. Future metadata collections might well include computational content description (spectral analysis of a visual resource, for example) that may not be embeddable in current network systems. In such a case this field might contain a link to such a description rather than the description itself.


Publisher

• Label: PUBLISHER

• The entity responsible for making the resource available in its present form, such as a publisher, a university department, or a corporate entity. The intent of specifying this field is to identify the entity that provides access to the resource.


Other Contributors• Label: CONTRIBUTORS • Person(s) or organization(s) in addition to

those specified in the CREATOR element who have made significant intellectual contributions to the resource but whose contribution is secondary to the individuals or entities specified in the CREATOR element (for example, editors, transcribers, illustrators, and convenors).


Date

• Label: DATE• The date the resource was made available in its

present form. The recommended best practice is an 8 digit number in the form YYYYMMDD as defined by ANSI X3.30-1985. In this scheme, the date element for the day this is written would be 19961203, or December 3, 1996. Many other schema are possible, but if used, they should be identified in an unambiguous manner.


Resource Type

• Label: TYPE • The category of the resource, such as home

page, novel, poem, working paper, preprint, technical report, essay, dictionary. It is expected that RESOURCE TYPE will be chosen from an enumerated list of types. A preliminary set of such types can be found at the following URL: http://www.roads.lut.ac.uk/Metadata/DC-ObjectTypes.html


Format• Label: FORMAT • The data representation of the resource, such as text/html,

ASCII, Postscript file, executable application, or JPEG image. The intent of specifying this element is to provide information necessary to allow people or machines to make decisions about the usability of the encoded data (what hardware and software might be required to display or execute it, for example). As with RESOURCE TYPE, FORMAT will be assigned from enumerated lists such as registered Internet Media Types (MIME types). In principal, formats can include physical media such as books, serials, or other non-electronic media.


Resource Identifier• Label: IDENTIFIER • String or number used to uniquely identify

the resource. Examples for networked resources include URLs and URNs (when implemented). Other globally-unique identifiers,such as International Standard Book Numbers (ISBN) or other formal names would also be candidates for this element.


Source

• Label: SOURCE

• The work, either print or electronic, from which this resource is derived, if applicable. For example, an html encoding of a Shakespearean sonnet might identify the paper version of the sonnet from which the electronic version was transcribed.


Language

• Label: LANGUAGE

• Language(s) of the intellectual content of the resource. Where practical, the content of this field should coincide with the Z39.53 three character codes for written languages. See: http://www.sil.org/sgml/nisoLang3-1994.html


Relation

• Label: RELATION• Relationship to other resources. The intent of specifying

this element is to provide a means to express relationships among resources that have formal relationships to others, but exist as discrete resources themselves. For example, images in a document, chapters in a book, or items in a collection. A formal specification of RELATION is currently under development. Users and developers should understand that use of this element should be currently considered experimental.


Coverage

• Label: COVERAGE

• The spatial locations and temporal duration characteristic of the resource. Formal specification of COVERAGE is currently under development. Users and developers should understand that use of this element should be currently considered experimental.


Rights Management

• Label: RIGHTS • The content of this element is intended to be a link (a URL

or other suitable URI as appropriate) to a copyright notice, a rights-management statement, or perhaps a server that would provide such information in a dynamic way. The intent of specifying this field is to allow providers a means to associate terms and conditions or copyright statements with a resource or collection of resources. No assumptions should be made by users if such a field is empty or not present.


SGML and XML Sources and Resources

• Books: van Herwijnen, Eric. Practical SGML. (2nd Ed.) Boston: Kluwer Academic Publishers, 1994.Goldfarb, Charles F. The SGML Handbook. Oxford: Clarenden Press, 1990. (And MANY XML books)

• Web Sites:– Robin Cover’s SGML/XML Site

http://www.oasis-open.org/cover/sgml-xml.html

–

http://www.oasis-open.org/cover/sgml-xml.html


Assignment 6

• Posted on course Web site.

• 1. Create a DTD for Dublin Core

• 2. Describe some items using Dublin Core

• 3. Your descriptions should be marked up using your DTD