A Mixed XML-JavaBeans Approach A Mixed XML-JavaBeans Approach to Developing t-Learning to Developing t-Learning

Applications for the Multimedia Applications for the Multimedia Home PlatformHome Platform

Martín López NoresMartín López NoresDepartment of Telematic EngineeringDepartment of Telematic Engineering

University of Vigo (Spain)University of Vigo (Spain)

First International Workshop onFirst International Workshop on

Multimedia Interactive Protocols and SystemsMultimedia Interactive Protocols and Systems

MIPS 2003MIPS 2003November 18-21, 2003 Napoli (Italy)November 18-21, 2003 Napoli (Italy)

OOrganizationrganization

Introduction to t-learning.Introduction to t-learning. The MHP standard.The MHP standard. Solutions for broadcast services.Solutions for broadcast services. Implementation details.Implementation details. Summary and future work.Summary and future work.

A FA Few ew WWords ords about t-about t-LLearningearning

A lot of work is being done on distance A lot of work is being done on distance learning.learning. In order to overcome the In order to overcome the limitations of limitations of

traditional learningtraditional learning.. Access to education is considered key to Access to education is considered key to

maintain a region’s maintain a region’s competitivenesscompetitiveness..

IIntroductionntroduction

Several major technological approaches have Several major technological approaches have been defined.been defined.

The future points towards The future points towards convergenceconvergence.. ObstaclesObstacles: networks, interoperability and users.: networks, interoperability and users. Currently, the Currently, the different mediumsdifferent mediums demand demand different different

solutionssolutions..

IIntroductionntroduction

t-learningt-learning

m-learningm-learninge-learninge-learningContinuous,

ubiquitous learning

t-t-LLearning’searning’s AAdvantages...dvantages...

There is at least one TV in There is at least one TV in nearly 100% of nearly 100% of householdshouseholds in developed countries. in developed countries. Internet not expected to go beyond Internet not expected to go beyond 70%70%..

Television is Television is easy to use easy to use for everybody.for everybody. IDTV helps to IDTV helps to prevent social exclusionprevent social exclusion in in

the access to education.the access to education. Overcomes Overcomes economical and cultural barrierseconomical and cultural barriers..

No need to buy a computer.No need to buy a computer. No need of technological knowledge.No need of technological knowledge.

... and ... and PPeculiaritieseculiarities

A set-top box is A set-top box is not a computernot a computer.. Lower Lower computing powercomputing power.. Limited Limited user interaction capabilitiesuser interaction capabilities..

A TV screen has A TV screen has low resolutionlow resolution. . Simple user interfaces with big visual elements.Simple user interfaces with big visual elements.

IDTV is a natural medium for IDTV is a natural medium for broadcastbroadcast and and handling handling multimedia contentmultimedia content..

Users are Users are predominantly passivepredominantly passive.. TV is considered as a medium for entertainment.TV is considered as a medium for entertainment. IDTV is ideal for IDTV is ideal for informal learning (informal learning (edutainmentedutainment))..

SStrategies for trategies for IInteractivitynteractivity

Applications Applications respondrespond to the user’s actions.to the user’s actions.

Typical in e-learning Typical in e-learning services.services.

The evolution of pieces of The evolution of pieces of media media guides usersguides users and and controls the controls the flow of flow of applicationsapplications. .

Main option for t-learning.Main option for t-learning.

User-driven

Media-driven

TThe he MHP MHP SStandardtandard

TThehe M Multimediaultimedia H Homeome PPlatformlatform Published by the Published by the DVB (DVB (Digital Video Digital Video

BroadcastingBroadcasting)) Consortium in February, 2000. Consortium in February, 2000. It defines a It defines a neutral frameworkneutral framework for IDTV for IDTV

applications and services.applications and services. Increasingly popularIncreasingly popular among broadcasters among broadcasters

and relevant enterprises.and relevant enterprises. Initially European ones.Initially European ones. The recent The recent GEM (GEM (Globally Executable MHPGlobally Executable MHP) )

specification prepares the way into the USA and specification prepares the way into the USA and Japan.Japan.

CCommunication ommunication IIssuesssues

Communication in IDTV is Communication in IDTV is highly assymetrichighly assymetric.. Broadcast networksBroadcast networks and and (optional)(optional) return channelsreturn channels..

The MHP framework:The MHP framework: MPEG-2 transport streamsMPEG-2 transport streams for broadcasting live audio and for broadcasting live audio and

video, and video, and DSM-CC object carrouselsDSM-CC object carrousels for other resources. for other resources. TCP/IPTCP/IP and and service-specific protocolsservice-specific protocols for the return for the return

channel.channel. The availability of a return channel determines the The availability of a return channel determines the

interactive capabilitiesinteractive capabilities.. Simulated and realSimulated and real interactivity. interactivity.

TThehe O Object bject CCarrouselarrousel

Main mechanism to Main mechanism to broadcast databroadcast data in MHP. in MHP. A group of files A group of files transmitted in a cyclical waytransmitted in a cyclical way. .

A A read-only filesystemread-only filesystem over an MPEG-2 transport over an MPEG-2 transport stream.stream.

Resources are not always available immediately Resources are not always available immediately when needed.when needed.

There may be There may be noticeable latenciesnoticeable latencies..

TThe he PProblem of roblem of LLatenciesatencies LatenciesLatencies can be extremely annoying. can be extremely annoying.

Example:Example: 520 KB @ 256 Kbps = ¡ 16 seconds per cycle !520 KB @ 256 Kbps = ¡ 16 seconds per cycle ! NobodyNobody would wait so long for a program to start. would wait so long for a program to start.

MHP offers several ways to control latencies:MHP offers several ways to control latencies: Caching, preloading and asynchronous loading Caching, preloading and asynchronous loading of of

contents.contents. Other contributions:Other contributions:

Adequate Adequate planningplanning of the carrousels. of the carrousels. Careful Careful constructionconstruction of the applications. of the applications.

TThehe MHP MHP PProfilesrofiles

MHP defines several MHP defines several receiver profilesreceiver profiles.. Features and cost Features and cost tailored to the services requiredtailored to the services required..

We pay special attention to We pay special attention to broadcast broadcast servicesservices.. InexpensiveInexpensive and fast to develop. and fast to develop. Suitable for Suitable for edutainmentedutainment.. Interactivity may drive users towards Interactivity may drive users towards more active more active

profilesprofiles in their use of TV. in their use of TV.

Extensions for e-mail and web browsing

Internetaccess

Return channel for real interactivity

Interactivebroadcast

Simulatedinteractivity

Enhancedbroadcast

PPrinciples of rinciples of the the

AArchitecturerchitecture

SStructure of the tructure of the CCoursesourses

SceneScene SceneScene

Element

Element

Element

UnitUnitManagerManager

Pedagogicalunit

Pedagogicalunit

Pedagogicalunit

Pedagogicalunit

CourseCourseManagerManager

CConditional onditional AAccessccess

Units have a Units have a locked/unlockedlocked/unlocked state. state. Can be changed in response to any event.Can be changed in response to any event.

The composition of a course is The composition of a course is summed up in a summed up in a directed graphdirected graph, , definingdefining The The orderingordering of the units. of the units. The The access dependenciesaccess dependencies..

This information must be available at This information must be available at the receivers.the receivers. Local take of decisionsLocal take of decisions..

22

33

11

CContextual ontextual BBindinginding

A A simple and effective solutionsimple and effective solution for the for the synchronization of multiple sources of information.synchronization of multiple sources of information. Including the broadcast streams (media-driven units).Including the broadcast streams (media-driven units).

It is based on It is based on contextscontexts.. Identifiers linked to pieces of information.Identifiers linked to pieces of information. Defined differently for the different types of content.Defined differently for the different types of content.

TimestampsTimestamps in fragments of audio and video. in fragments of audio and video. RegionsRegions in images. in images. AnchorsAnchors in a text. in a text. OptionsOptions in menus, etc. in menus, etc.

TTemplates emplates (I)(I)

TemplatesTemplates are a common feature in many are a common feature in many development tools.development tools. Make development tasks Make development tasks fasterfaster.. Enhance Enhance software reusesoftware reuse.. Help to Help to separate content from graphical appearanceseparate content from graphical appearance..

Their use in IDTV applications offers additional Their use in IDTV applications offers additional advantages.advantages.

TTemplates emplates (II)(II)

Templates are configured Templates are configured during runtimeduring runtime.. Not at design time.Not at design time.

The cost of runtime configuration is The cost of runtime configuration is masked by masked by latencies and loading timeslatencies and loading times..

XMLfile

Templatesrepository

RuntimeRuntimeconfigurationconfiguration

UnitUnittemplatetemplate

Bla, bla, bla,Bla, bla, bla,bla, bla, bla,bla, bla, bla,bla, bla, bla.bla, bla, bla.

1 32

Fully-specified unitFully-specified unit

TTemplates emplates (III)(III)

The object carrousel transportsThe object carrousel transports the Java class file of the template,the Java class file of the template, much smallermuch smaller XML configuration files. XML configuration files.

AdvantagesAdvantages:: More files can be kept in the cache.More files can be kept in the cache.

Higher efficiencyHigher efficiency. . The size of the carrousel decreases.The size of the carrousel decreases.

Lower round-trip timeLower round-trip time lower latencieslower latencies..

IImplementatiomplementationn

DDetailsetails

DDesign esign GGoalsoals

No need of No need of programming knowledgeprogramming knowledge.. FlexibilityFlexibility and support for all the phases of and support for all the phases of

development.development. Based on Based on free, open technologiesfree, open technologies..

Low cost.Low cost. Extensibility.Extensibility. Interoperability.Interoperability.

TTypes of ypes of AApplicationspplications

Applications Applications programmed in Java.programmed in Java.

Two main restrictions:Two main restrictions: MHP MHP APIsAPIs.. XletXlet lifecyclelifecycle.. A declarative A declarative

languagelanguage, based , based on on Internet standardsInternet standards.. XHTML, CSS, XHTML, CSS, cookiescookies, ,

etc.etc.

DVB-J

DVB-HTML

FFoundational oundational TTechnologies: echnologies: XMLXML

A A standard syntaxstandard syntax for for the the compositioncomposition of the courses, of the courses, the the configuration filesconfiguration files for a template, for a template, the the definition of contextsdefinition of contexts in the different types of in the different types of

information.information. Also used when assembling pedagogical Also used when assembling pedagogical

units.units. To communicate with To communicate with content-management content-management

systemssystems.. SCORM, IMS, etc. SCORM, IMS, etc.

FFoundational oundational TTechnologies: echnologies: JJavaavaBBeanseans

A A components architecture components architecture for Java.for Java. Promotes Promotes components reusecomponents reuse.. Provides for Provides for visual developmentvisual development..

Beans are Beans are building blocks building blocks to construct to construct applications.applications. Interrelations handled by means of Interrelations handled by means of event event

adaptersadapters.. Enough for simulated interactivity.Enough for simulated interactivity. Not for non-broadcast services.Not for non-broadcast services.

A CASE TA CASE Tool for t-ool for t-LLearningearning We have implemented our approach on top of We have implemented our approach on top of

the NetBeans Platformthe NetBeans Platform.. Features:Features:

Entirely visualEntirely visual development. development. SimpleSimple assembling of pedagogical units assembling of pedagogical units..

By retrieving content from repositories or creating it By retrieving content from repositories or creating it ad-ad-hochoc..

Several Several wizards and assistant toolswizards and assistant tools.. To define the composition of the courses.To define the composition of the courses. For the automatic creation of For the automatic creation of multiple-choice testsmultiple-choice tests.. To To delimit contexts delimit contexts in the different types of information.in the different types of information.

Automatic Automatic generation of the transport streamsgeneration of the transport streams..

SSummary and ummary and FFuture uture WWorkork

MMainain C Conclusionsonclusions

Human and technical factors Human and technical factors advice against direct advice against direct translation of e-learning solutions.translation of e-learning solutions.

Broadcast servicesBroadcast services are essential at an initial stage. are essential at an initial stage. Preparing the way towards highly-interactive services.Preparing the way towards highly-interactive services. The MHP standard provides The MHP standard provides a satisfactory platforma satisfactory platform..

Simulated interactivity.Simulated interactivity. Latencies.Latencies. Predominance of multimedia contents.Predominance of multimedia contents.

Essential distinction between Essential distinction between user-drivenuser-driven and and media-drivenmedia-driven strategies. strategies.

FFutureuture W Workork

Exploit the power of the return channel.Exploit the power of the return channel. Real interactivityReal interactivity with applications and other with applications and other

users.users. PersonalizationPersonalization of contents. of contents. Creation of Creation of virtual learning communitiesvirtual learning communities, ,

involving people with shared interests.involving people with shared interests. Analyze new multimedia formats: Analyze new multimedia formats: MPEG-4MPEG-4..

EEndnd