Using Multimedia

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Using Multimedia

Presentations on Web

Mihaela Brut

Faculty of Computer Science

« AL. I Cuza » University of Iasi, Romania, [email protected]

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Agenda

9 Introduction 9 SMIL language

9 XQuery Language

9 A short presentation of RDF 9 Structure of the

E-learning Platform

9 The Web Platform Modularization 9 Managing multimedia information 9 Conclusions and Further Work

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Introduction

• In education, Internet

⇒ an object to study and

a bibliographical / imagistic source

• e-learning involves

a user-centred interface design

• SMIL ⇒ teaching materials as multimedia Web presentations

• XQuery ⇒ for retrieving the

information inside XML documents

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Introduction

• Public sites, free courses:

BBCi, Discovery, Fathom

• Distance Learning Institutions:

CNED, NetLearn Languages

• Virtual Universities: Open University,

University of Phoenix Online, Universidad Nacional de Education a Distancia

• Universities with on-line programs:

L' Université Rennes 2 - Haute Bretagne, Universitat Autonoma de Barcelona

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Introduction

Terminology

• Computer-Base Learning

• Web-Based Learning

• Web-Based Teaching

• Web-Base Course Environment

• Virtual classroom

• Networked Learning

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Introduction

E-learning institutions:

• providers of educational opportunities

• didactic, consultancy, testing,

examination or evaluation materials

• alliances or partnerships

Educational brokers

Consortiums ⇒ supporting the

Information Technology in education In Romania: Academia on-line,

Şcoala on-line, 1 Educat, Timsoft

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Our Proposal

• A management system of multimedia information inside an Open Distance Learning section Web site

• Advantages:

–the multimedia information is distributed –metadata (SMIL, RDF) facilitate the

search inside multimedia (XQuery)

–open-source software can be used

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SMIL

• Synchronized Multimedia Integration

Language, since 1998, by WWW Consortium

• purpose:

interactive multimedia presentations

• the components could be executed in

a sequential, parallel or combined manner

• SMIL 2.0 is defined as a set of reusable markup modules (see XHTML and SVG)

• special players: RealOne (RealNetworks), GRiNS (Oratrix), Ambulant (CWI)

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SMIL – ex.

<!DOCTYPE smil PUBLIC "-//W3C//DTD SMIL 2.0//EN"

"http://www.w3.org/TR/REC-smil/SMIL20.dtd">

<smil xmlns="http://www.w3.org/2001/SMIL20/Language">

<head> <layout type=”smil-basic-layout”>

<region id="MoviePlace" top="5" left="25" width="875"

height="650"/>

<region id="TextPlace" top="655" left="25" width="875"

height="20"/>

</layout></head>

<body>

<par>

<audio src=”background.mp3” dur=”30s”>

<video region=”MoviePlace” src=”tutorial.avi”>

<text region=”TextPlace” src=”explain.html” dur=”30s”>

</par> </body>

</smil>

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SMIL

• presentation’s files could be distributed stored

• a presentation can play only in a region of the site,

having no interaction with the rest

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XQuery -

requirements

• Data extraction from huge

XML documents, by processing the

structural part and the textual content

• Syntax based on other XML standards:

XPointer, XSL, XPath, XML Schema...

• XML data transfer between documents with eterogeneous ontologies (DTDs)

• Querying of distributed data, in various XML formats

• Expressing the queries results in

XML format

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XQuery

The formal model:

• Document - represented as a tree;

• Nodes: document, element, attribute, text, namespace,

processing instruction, and comment

• Atomic values —simple data types

• An item — an atomic value or an individual node;

• Secquence — series of items

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XQuery

• Literals: numerical, strings

• Functions: doc(), collection()

• Path expresions:

doc("course.xml")/bib/book

• Predicates:

doc("course.xml")/lesson[@year="04"]

• Constructors: creation of elements, atributes, textual nodes, processing instructions, or comments.

• FLWOR expressions:

for, let, where, order by, return

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RDF

• Resource Description Framework

• Standardized basis for processing metadata

• Three object types:

resources, properties, statements

• three types of container objects:

Bag, Sequence, Alternative

• Knowledge Portals, E-Marketplaces

• Querying RDF: XQuery, RQL, Algae, Squish, DQL, RuleML, etc.

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E-learning Platform

Structure:

a public section, and private sections for students, instructors, and

administrative stuff Content:

didactic materials with heterogeneous formats and structures, academic and administrative information

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E-learning Platform

Student area:

• Acces to the enrolled courses,

• homework topics,

• a private announcements section,

• student services/organiyaations list,

• personal information manager,

• file directory, e-mail account, personal profile, search facilities

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E-learning Platform

Course area:

• course announcements, calendar,

• the course materials,

• the associate resources (textbooks, software tools, Web resources),

• the workgroups’ section

• e-mail, discussions forum, access to

virtual classrooms and videoconferences

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E-learning Platform

Instructor area:

• editing didactic materials,

• managing students, the exams, the on-line catalogue

• posting announcements,

• establishing the course calendar,

the homework, the dates for virtual classrooms or videoconferences,

• indicating the useful Web resources,

• generating the course statistics

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E-learning Platform

Problems:

• To be provided access to

materials and applications only to the appropriate persons

⇒ access policies

• To transmit the information from an application to another

⇒ XML format

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E-learning Platform

Multimedia metadata:

• SMIL elements <ref>, <video>,

have the attributes:

– alt, longdesc, abstract, title

– begin, end, dur, repeat, repeatCount, clip-begin, clip-end

• This information can be extracted with XQuery

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E-learning Platform

<video src=”http://www.infoiasi.ro/campus.avi”

title=”Virtual Campus Tour”

alt=”Enjoy a virtual tour through the university campus”

abstract=”The video file offers a virtual tour through the university campus, illustrating the academic life during the

courses and practical works classes, during the examinations and the spare time”

longdesc=”

http://www.infoiasi.ro/campus-description.html”

/>

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Ex. XQuery

<rdf:Bag rdf:id="video-meta-information">

{for $v in doc("tutorial.smil")//video return {

<rdf:li>

<rdf:Description rdf:about="$v[@src]">

<d:meta>

<d:type elem="video">image/video</d:type>

<d:title>{$v[@title]}</d:title>

<d:alt>{$v[@alt]}</d:alt>

<d:longdesc>{$v[@longdesc]}</d:longdesc>

</d:meta>

</rdf:Description>

</rdf:li> } }

</rdf:Bag>

<rdf:Description rdf:about="#video-meta-information">

</rdf:Description>

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Resulted RDF

<rdf:Bag rdf:id="video-meta-information">

<rdf:li>

<rdf:Description rdf:about="campus.avi">

<d:meta id="v1">

<d:type elem="video">video/avi</d:type>

<d:title> Virtual Campus Tour </d:title>

<d:alt> Enjoy a virtual tour ... </d:alt>

<d:abstract>The video file offers ... </d:abstract>

<d:longdesc>http://www.infoiasi.ro

/campus-description.html </d:longdesc>

</d:meta>

</rdf:Description>

</rdf:li>

<!—other similar RDF constructs about the other books -->

</rdf:Bag>

<!—the file containing the video resources collection -->

<rdf:Description rdf:about="#video-meta-information">

</rdf:Description>

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Processing RDF

<rdf:Bag>{

for $g in doc ("multimedia.rdf")//rdf:Bag for $m in $g/rdf:li/rdf:Description/d:meta)

let $t := $m/d:title [contains(string(.), "campus ")]

let $a := $m/d: alt [contains(string(.), "campus ")]

let $b:=$m/d:abstract [contains(string(.), "campus ")]

where exists($t) or exists($a) or exists($b) return

<rdf:li>

for $s in doc

("multimedia.rdf")//rdf:Description[@about=$g[@id]) let $n=$s/source

return { $n

<d:video>$g/rdf:Description[@about] }

</rdf:li>

} </rdf:Bag>

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Processing solutions

DOM (Document Object Model) and SAX (Simple API for XML) models

⇒For incorporating the RDF sequence resulting from the first query in the general RDF file

⇒For implementing all queries XQuery Lite PHP library

⇒ to process XQuery constructs

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Conclusions

• Our proposal overcomes:

– SMIL solution for building

multimedia educational materials – RDF for gathering multimedia

metadata

– XQuery for retrieving multimedia

information

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Using Multimedia