1. WMES3103 : INFORMATION RETRIEVAL
TEXT AND MULTIMEDIA LANGUAGES AND PROPERTIES

2. INTRODUCTION Text - main form of communicating data and information
Text also supplemented with multimedia elements - to make the contents of an IRS more attractive and interactive
Website with a combination ot text and multimedia will be visited by many as compared to one which is text-based only
IRS - text and multimedia is depicted via special languages.

3. Metadata New concept on information – metadata
Information about data arrangement, data domain and relationship between the two
Data about data
2 types – descriptive and semantic

4. Commonly used Metadata :
descriptive Metadata – metadata which explain about document or one unit of information
Commonly used Metadata :
Authors
Date of publication
Source of publication
Length of document
Type of document

6. Metadata
semantic Metadata –resembles subject that can be obtain from the contents of the document – subjects heading
Keywords
LC Code

7. TEXT With computers, we need to code text into binary digits
First coding schemes – EBCDIC and ASCII – 7 bits to code each symbol
Then, ASCII changed to 8 bits to accommodate other languages, accents and diacritical marks
Oriental languages – Unicode – 16 bits

8. TEXT Formats No one single format for a text document
Good IRS system should be able to retrieve information from any format
Initially, IRS will convert a document to an internal format but this had a lot of disadvantages
Now, many new format has been developed for document interchange

9. TEXT RTF – Rich Text Format for word processing
PDF – Portable Document Format for displaying and printing documents
Postscript – powerful programming language for drawing
MIMT – Multipurpose Internet Mail Exchange to encode
Files are compressed – Compress (Unix), ARJ (PCs), ZIP
Convert binary files to ASCII text –uuencode/uudecode, binhex

10. MARKUP LANGUAGES
Markup = extra textual syntax that can be used to describe formatting actions, structure information, text semantics, attributes, etc.
Formal markup languages are more structured
Marks = tags - initial and ending tag surrounding the marked text
Standard metalanguage = SGML
New metalanguange for Web = XML (eXtensible Markup Language) = subset of SGML
Most popular markup language used for the Web = HTML (HyperText Markup Language)

11. MULTIMEDIA
Applications that handle different types of digital data originating from distinct types of media
Text, sound, images, video
Digital data distinct and different in volume, format, and processing requirements
Different types of formats necessary for storing each type of media

12. MULTIMEDIA
Different formats used commonly on the Web and in digital libraries
Images
Audio
Moving Images
Textual Images
Graphics and Virtual Reality

13. IMAGES
XBM, BMP, PCX – direct representation of a bit-mapped (or pixel-based)
GIF (Graphic Interchange Format) – includes compression and good for black or white or with small number of clours or gray levels (256)
JPEG (Joint Photographic Experts Group) – includes compression
TIFF (Tagged Image File Format) – used to exchange different documents between different applications and different computer platforms
TGA (Television Targa image file) – associated with video game boards
Various other image formats

14. AUDIO Must be digitized before storage
AU, MIDI (standard format to interchange music between electronic instruments and computers), WAVE – for small pieces of digital audio
Audio libraries – RealAudio or CD formats
Animation or moving pictures
MPEG (Moving Pictures Expert Group) – related to JPEG
Others – AVI, FLI, QuickTime

15. TEXTUAL IMAGES Images that contain mainly typed or typeset text
Obtained by scanning the documents
For archival purposes
Saved as images but with further compression
Textual and non-textual stored and compressed separately and when neded can be combined and displayed together

16. GRAPHICS AND VIRTUAL REALITY
3-dimensional graphics found on Web
CGM (Computer Graphics Metafile) standard
Metafile = collection of elements
CGM standard specifies which elements are allowed to occur in which positions in a metafile
VRML (Virtual Reality Modeling Language) – file format for describing interactive 3D objects and worlds - universal interchange format for 3D graphics and multimedia - can be used for various applications

17. MULTIMEDIA DOCUMENTS MARKUP
HyTime = Hyper/Time-based Structuring Language – standard defined for multimedia documents markup
SGML architecture which specifies the generic hypermedia structure of documents