Chapter 6 Text and Multimedia Languages and Properties

1
Chapter 6Text and Multimedia Languages and
Properties

• Hsin-Hsi Chen
• Department of Computer Science and Information
  Engineering
• National Taiwan University

Part of the materials in the following is
selected from Dr Kuang-hua Chens talk on XML and
RDF (Department of Library Information Science,
National Taiwan University)
2
what is a document

• document a single unit of information
• complete logical unit
• research paper, book, manual
• part of a larger text
• paragraph, passage, an entry in a dictionary,
• a physical unit
• file, email, Web page

3
characteristics of a document
How a document is displayed or printed
Document
Presentation Style
Text Structure Other Media
Syntax
Semantics
Express structure, presentation style, or even
external actions
Author
implicit, or expressed in a language
Creator
4
Metadata(???,???,????,????,????,????)

• Definition
• Data about the data, e.g., schema in a DBMS
• describe other information based on some rules or
  policies
• Type
• Descriptive Metadata
• Metadata that is external to the meaning of the
  document
• Dublin Core
• Semantic Metadata
• Metadata that can be found within the documents
  content
• Library of Congress subject codes

5
Dublin Core

• Metadata Element Set (15)
• ??????(Subject)
• ?????,?????????????????,???????????
• ??(Title)
• ???????????????
• ??(Creator)
• ???????????????
• ??(descriptions)
• ?????????,???????????????
• ???(Publisher)
• ???????,????????????????

6
Dublin Core (Continued)

• ?????(Contributors)
• ?????????????????,???????????
• ????(Date)
• ???????
• ????(Type)
• ?????,??????????????????
• ????(Format)
• ???????,??text/html?ASCII???JPEG????
• ??????(Identifier)
• ???????????????,??????URL?URN,??ISBN???????

7
Dublin Core (Continued)

• ??(Relation)
• ????????,????????????
• ??(Source)
• ??????????
• ??(Language)
• ??????????
• ????(Coverage)
• ??????????
• ????(Rights)
• ?????????????????

8
?????

• lt?xml version"1.0"?gtltdc-recordgt
• lttypegt??lt/typegt
• ltformatgt????lt/formatgt
• ltformatgt??lt/formatgt
• lttitlegt??????????lt/titlegt
• lttitlegtcloisonnie box with lotus-spray
  decorationlt/titlegt
• ltdescriptiongt1400/1500lt/descriptiongt
• ltdescriptiongt??,??????????????lt/descriptiongt
• ltdescriptiongt?63.cm ??12.4cm ?634.6?lt/descriptiongt
  
• ltdescriptiongt???,???????????????????,?88?2??lt/des
  criptiongt

9
?????(?)

• ltsubjectgt??????????lt/subjectgt
• ltsubjectgt????lt/subjectgt
• ltsubjectgt??lt/subjectgt
• ltsubjectgt????lt/subjectgt
• ltsubjectgt??lt/subjectgt
• ltsubjectgt??(??????)(r) placelt/subjectgt
• ltdategt1400/1500lt/dategt
• ltcoveragegt??(??????)(r) placelt/coveragegt
• ltrightsgt??,??lt/rightsgt
• lt/dc-recordgt

10
???????

• lt?xml version"1.0"?gtltdc-recordgt
• lttypegt????lt/typegt
• lttypegt??lt/typegt
• lttitlegt????lt/titlegt
• ltdescriptiongt??lt/descriptiongt
• ltdescriptiongt????lt/descriptiongt
• ltdescriptiongt3048.7lt/descriptiongt
• ltdescriptiongt?????????????????????????????????????
  ?????????????????????????????????????????????lt/des
  criptiongt

11
???????(?)

• ltdescriptiongt1127/1189lt/descriptiongt
• ltdescriptiongt????????????,????????????????????,?8
  4?9??lt/descriptiongt
• ltsubjectgt??lt/subjectgt
• ltcreatorgt???lt/creatorgt
• ltdategt1127/1189lt/dategt
• ltlanguagegtzhlt/languagegt
• ltrightgt??,??lt/rightgt
• lt/dc-recordgt

12
MARC

• Machine-Readable Cataloging Record
• The most used format for library records
• An Example (NTU Lib)?? ?????? Public
  art in Taiwan eng ??? ??????
  ??? ?????????? ?88-??? 1999.???
  ? ?? 29???? ??87???????????
  csh ???? -- ?????? ? ?????
  100982322.??? 100982322.????? 957-02-4
  468-2 ?? NT500.????? cw 88008821.

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Web Metadata

• purposes
• cataloging (e.g., BibTex)
• content rating
• Protect children from reading some type of
  documents
• intellectual property rights
• digital signatures (for authentication)
• privacy levels
• applications to electronic commerce
• RDF (Resource Description Framework)

14
RDF

• description of nodes and attached attribute/value
  pairs
• nodes any Web resource
• attributes properties of nodes
• values text strings or other nodes (Web
  resources or metadata instances)

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RDF????
Resource
Property
Value
Subject Predicate Object
Statement
16
???
??? ???
17
RDF????
Resource
Resource
Property
Property
Property
value
value
18
???
??? ???
Dummy
??
????
??
?????
Tenzi_at_ac.jp
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Name Space

• ???????????????
• ????????????????
• ??
• ltRDF xmlnshttp//www.w3.org/TR/WD-rdf-synta
  x/
• xmlnsdchttp//purl.org/dc/elemen
  ts/1.0/gt

Name Space
Dublin Core
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DC in RDF
dctype
dccoverage
Resource
dctitle
dccreator
dcsubject
dccontributor
dcdescription
dcpublisher
dcidentifier
dcdate
dcrights
dcrelation
dclanguage
dcformat
dcsource
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A DC Example in RDF
http//x.html
Kevin Chen
dccreator
ltRDF xmlns http//www.w3.org/TR/WD-rdf-syntax
xmlnsdc http//purl.org/dc/element
s/1.0/gt ltDescription about
http//x.htmlgt ltdccreatorgt Kevin
Chen lt/dccreatorgt lt/Descriptiongt lt/RDFgt
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RDF??
dctitle
http//www.lis.ntu.edu.tw/khchen/
The Magic Shelter
Kuang-hua Chen
dccreator
ltRDF xmlns http//www.w3.org/TR/WD-rdf-syntax
xmlnsdc http//purl.org/dc/element
s/1.0/gt ltDescription about
http//www.lis.ntu.edu.tw/khchen/gt
ltdcTitlegt The Magic Shelter lt/dcTitlegt
ltdcCreatorgt Kuang-hua Chen lt/dcCreatorgt
lt/Descriptiongt lt/RDFgt
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Text

• Formats
• Basic form
• ASCII,
• Document interchange
• Rich Text Format (RTF) used by word processors
• Portable Document Format (PDF) and Postcript
  used for display or printing documents
• MIME (Multipurpose Internet Mail Exchange)
  support multiple character sets, multiple
  languages, and multiple media

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Text (Continued)

• compress
• Compress (Unix)
• ARJ (PCs)
• ZIP (gzip in Unix and Winzip in Windows)

25
Information Theory

• entropy
• Measure information content or information
  uncertainty

where ? is the number of symbols in the alphabet
pi is a probability for symbol i
26
Modeling Natural Language

• Issue 1 how a word is formulated
• symbols (separate-words and belong-to-words)
• Vowels are more frequent than most consonants
• Binomial model (0-order Markov model) each
  symbol is generated with a certain probability
• k-order Markov model
• Extension how a sentence is formulated
• 5-order Markov model in Bible
• finite-state model (regular languages)
• grammar model (context free and other languages)

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Modeling Natural Language(Continued)

• Issue 2 how different words are distributed
  inside each document
• Zipfs law
• The frequency of the i-th most frequent word is
  1/i? times that of the most frequent word
• In a text of n words with a vocabulary of V
  words, the i-th most frequent word appears n
  /(i?HV(?))

?1.52.0
28
There are a few hundred words which take up 50
of the text. Words (stopwords) that are too
frequent can be disregarded.
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Modeling Natural Language(Continued)

• Issue 3 the distribution of words in the
  documents of a collection
• Negative binomial distribution
• The fraction of documents containing a word k
  times

p9.24 and ?0.42 for word said in Brown corpus
where p and ? depend on the word and the
document collection
30
Modeling Natural Language(Continued)

• Issue 4 number of distinct words in a document
  (document vocabulary)
• Heaps Law
• The vocabulary of a text of size n words isV
  Kn?where K and ? depend on the particular
  textK between 10 and 100? a positive value
  less than 1 (e.g., 0.4 lt ? lt 0.6)

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Modeling Natural Language(Continued)

• Issue 5 average length of words
• Heaps law
• The length of the words in the vocabulary
  increases logarithmically with the text size

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Similarity Model

• distance function
• symmetric distance(a,b)distance(b,a)
• triangle inequality distance(a,c)?distance(a,b)
  distance(b,c)
• measure
• Edit distance minimum number of character
  insertions, deletions, and substitutionse.g.,
  Edit-distance(color, colour)1,
  Edit-distance(survey, surgery)2
• Longest common subsequence only deletion is
  allowede.g., LCS(survey, surgery)surey
  (non-common is deleted)
• Longest common sequence of lines between two
  files e.g., diff command in Unix

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Markup Languages

• Definition
• Textual syntax that describes formatting actions,
  structure information, text semantics,
  attributes, etc.
• Types
• Procedural Markup
• Descriptive Markup

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????? (Procedural Markup)
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????? (Descriptive Markup)
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????????

• ??????????????
• ?????????????

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SGML(Standard Generalized Markup Language)

• 1986? ISO ??????-ISO 8879
• ????????
• ??? Meta-language
• HTML ? SGML ????

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SGML ???

• ??? (flexibility)
• ?????????????????
• ???? (non-proprietary)??????(platform-independence
  ) ?????? (system-independence)
• ?????????????
• ?????? (re-usability)

39
SGML?????

• SGML declaration
• ??????????,?????????
• DTD (Document Type Definition)
• ???????? elements?
• ?? elements ???????
• ...
• DI (Document Instance)
• ????????

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SGML Declaration

• ?? SGML ????????,?????????
• ??????? SGML declaration,????? SGML ????????????
• lt!SGML ISO 8879-1986 ...

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Example Email ?????
Email
From
Body
Date
Subject
To
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An SGML DTD for Email
starting and ending tags compulsory(-) or
optional (O)
comment

• lt!-- Elements Min Content
  --gt
• lt!-- ----------- -----
  ---------------------------------- --gt
• lt!ELEMENT Email -- (From,Date,To,Subject,
  
• 
  Body?)gt
• lt!ELEMENT From -O (PCDATA)gt
• lt!ELEMENT Date -O (PCDATA)gt
• lt!ELEMENT To -- (PCDATA)gt
• lt!ELEMENT Subject -O (PCDATA)gt
• lt!ELEMENT Body -- (PCDATA)gt
• lt!-- End of Email DTD --gt

, concatenation logical or ? 0 or 1
occurrence 0 or ?1 occurrences ?1
occurrences
PCDATA ASCII characters NDATA binary data EMPTY
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An SGML DI for Email DTD

• lt!DOCTYPE Email SYSTEM c\temp\email.dtdgt
• ltEmailgt
• ltFromgtJoe
• ltDategt1999-7-14 AM 0920
• ltTogtJaylt/Togt
• ltTogtJenniferlt/Togt
• ltSubjectgtLearning XML
• ltBodygtXML ?? Web ?????,????!
• lt/Bodygt
• lt/Emailgt

user defined (vs. PUBLIC)
The ending tag is optional
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(No Transcript)
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SGML, DTDs, Document Instances, and Presentation
Instances
SGML
.
DTD
DTD
.
DI
DI
DI
.
????
Hypertext??
??????
DSSSL (Document Style Semantic Specification
Language) FOSI (Formatted Output Specification
Instance)
46
SGML?????

• SGML????????
• SGML?????Web???
• ???????

47
HTML (Hypertext Markup Language)

• ? SGML ???
• HTML 2.0 DTD
• HTML 3.2 DTD
• HTML 4.0 DTD
• ?? Web ????????????
• ????
• ???? (portable)
• ?????? (hyperlink) ????

Most HTML instances do not explicitly make
reference to the DTD
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HTML???

• HTML DTD ???????????????
• HTML?????? (style)
• HTML??SGML???????? (markup minimization feature)
• HTML???? SGML ??????

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HTML???

• ??????
• ????????
• ???????
• ?????????
• ??????????
• ??????? HTML Extension ???

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XML (eXtensible Markup Language)

• W3C Recommendation 10-February-1998
• XML 1.0
• ????Microsoft?Netscape?Sun ?...
• XML is SGML-- rather than HTML
• ? SGML??,? HTML??
• ?????????,???? tags
• ?? Web ???

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W3C Data Format
http//www.w3c.org/
52
XML??????

• ???? (Extensibility)
• XML????????,???????
• ??? (Structure)
• XML?????????????
• ???? (Validation)
• XML???? DTD ??????????

53
XML??

• XML-LanguageSGML without tears
• Self-describing Documents
• Well-formed and Valid Documents
• XML-LinkPower linking
• simple and extended links
• XML-StyleSeparate style from content
• XSL (Extensible Style sheet Language)

54
XML??????

• XML 1.0
• W3C Recommendation 10-Feb-1998
• XML Namespace
• W3C Recommendation 14-Jan-1999
• XLink Xpointer
• W3C Working Draft 03-March-1998
• XSL
• W3C Working Draft 16-Dec-1998

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Well-formed XML Rules

• ??????? elements
• ???? root element
• ???? start-tag ? end-tag
• ??? tags ????????? (nest) ???
• ( ? ltBgtltIgtbold and italiclt/Bgtitaliclt/Igt ?????
  )
• empty tags ???????XML???
• ( ? ltimg src/gt )
• ??? attribute value ???????????.
• ( ? ltfont size2gt )
• ??????????

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Writing Well-Formed XML

• Step 1 Make an XML Declaration
• Step 2 Creating a Root Element
• Step 3 Writing in XML
• Step 4 Parsing your document

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Step 1Make an XML Declaration
without DTD

• lt?xml version1.0 standaloneyes?gt
• lt?xml version1.0 encodingUTF-8
  standaloneyes?gt
• lt?xml version1.0 encodingbig5
  standaloneyes?gt

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Step 2Creating a Root Element

• lt?xml version1.0 standaloneyes?gt
• ltEmailgt
• lt/Emailgt

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Step 3Writing in XML

• lt?xml version1.0 encodingbig5
  standaloneyes?gt
• ltEmailgt
• ltFromgtJoelt/Fromgt
• ltDategt1999-7-14 AM 0920lt/Dategt
• ltTogtJaylt/Togt
• ltTogtJenniferlt/Togt
• ltSubjectgtLearning XMLlt/Subjectgt
• ltBodygtXML ?? Web ?????,????!
• lt/Bodygt
• lt/Emailgt

End tag cannot omitted
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Step 4Parsing your document

• Checking if your well-formed XML document
  conforms to well-formed XML rules.
• Use a parser to check well-formedness
• for example the XML parser embedded in IE5

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Explorer 5.0 ??Well-formed XML
62
Explorer 5.0 ?????XML??
63
Writing Valid XML

• Step 1 Make an XML declaration.
• Step 2 Designing a DTD.
• Step 3 Writing Valid XML.
• Step 4 Parsing your Valid XML document.

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Step 1Make an XML Declaration

• lt?xml version1.0 standaloneno?gt
• lt?xml version1.0 encodingUTF-8
  standaloneno?gt
• lt?xml version1.0 encodingbig5
  standaloneno?gt

65
Step 2 Designing a DTD

• lt!-- Elements Content
  --gt
• lt!-- ----------- -------------------
  --------------- --gt
• lt!ELEMENT Email (From,Date,To,Subject,Body?)gt
• lt!ELEMENT From (PCDATA)gt
• lt!ELEMENT Date (PCDATA)gt
• lt!ELEMENT To (PCDATA)gt
• lt!ELEMENT Subject (PCDATA)gt
• lt!ELEMENT Body (PCDATA)gt
• lt!-- End of Email DTD --gt

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Step 3 Writing Valid XML

• lt?xml version1.0 encodingbig5
  standaloneno?gt
• lt!DOCTYPE Email SYSTEM email.dtd"gt
• ltEmailgt
• ltFromgtJoelt/Fromgt
• ltDategt1999-7-14 AM 0920lt/Dategt
• ltTogtJaylt/Togt
• ltTogtJenniferlt/Togt
• ltSubjectgtLearning XMLlt/Subjectgt
• ltBodygtXML ?? Web ?????,????!
• lt/Bodygt
• lt/Emailgt

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XML Simple Link
68
XML Extended linking multiple ends
69
XML Extended linkingaddressing by structure
70
XML Extended linking
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XSL XML counterpart of CSS (Cascading Style
Sheet)

• Sample email.css
• Email,From,Date,To,Subject,Body,
• displayblockmargin-left5
• margin-right5border-stylegroove

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XML document with Style

• lt?xml version1.0 encodingbig5
  standaloneno?gt
• lt?xml-stylesheet href "email.css"
  type"text/css"?gt
• ltEmailgt
• ltFromgtJoelt/Fromgt
• ltDategt1999-7-14 AM 0920lt/Dategt
• ltTogtJaylt/Togt
• ltTogtJenniferlt/Togt
• ltSubjectgtLearning XMLlt/Subjectgt
• ltBodygtXML ?? Web ?????,????!
• lt/Bodygt
• lt/Emailgt

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Explorer 5.0 ????CSS?XML??
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XML???

• Database interchange
• Client-side processing
• User views of the data
• Information filtering

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Multimedia

• medias
• text, sound, images, video
• issues
• volume, format, processing requirements

76
Formats

• image
• bit-mapped/pixel-based display
• The simplest format
• XBM, BMP, PCX
• disadvantages redundancy
• compression
• Compuserves Graphic Interchange Format (GIF)
• lossy compression
• Joint Photographic Experts Group (JPEG)
• exchange
• Tagged Image File Format (TIFF)

77
Formats

• Audio
• AU, MIDI, WAVE
• Video
• MPEG, AVI, QuickTime

78
Textual Images

• definition
• images of documents that contain mainly typed or
  typeset text
• obtained by OCR
• image retrieval
• Alternative 1
• At creation time, a set of keywords (called
  metadata) is associated with each image
• Conventional text retrieval techniques can be
  applied to keywords

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Textual Images (Continued)

• Alternative 2
• Use OCR to extract the text of the image
• The resultant ASCII text can be used to extract
  keywords
• Alternative 3
• Use the symbols extracted from the images as
  basic units to combine image retrieval techniques
  with sequence retrieval techniques

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Taxonomy of Web languages
81
????

• HTML-4 http//www.w3.org/TR/REC-html40
• W3C http//www.w3c.org/
• OCLC http//purl.oclc.org/
• XML http//www.xml.org/
• XML Parser http//xdev.datachannel.com/
• DDML Document Definition Markup Language.
  http//www.w3.org/TR/NOTE-ddml
• Xschema http//purl.oclc.org/NET/xschema

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????

• J. Kunze, Encodeing Dubin Core Metadata in
  HTML, ltftp//ftp.ietf.org/internet-drafts/draft-k
  unze-dchtl-00.txtgt.
• E. Miller, P. Miller and d. Brickley, Guidance
  on Expressing the Dublin Core within the Resource
  Description Framework (RDF), lthttp//www.ukoln.ac
  .uk/interop-focus/activites/dc/datamodel/WD-dc-rdf
  -19990423.htmgt.