RDFa versus Microformats: Exploring the Potential for Semantic Interoperability of Mash-up Personal Learning Environments

Vladimir Tomberg, Mart Laanpere Tallinn University, Narva mnt. 25, 10120 Tallinn, Estoniavtomberg@tlu.ee, mart.laanpere@tlu.ee

A Course as dynamic process

Mash-up PLE have become a fast developing trend

Course is not just a syllabus, it also involves various dynamic processes

These processes can be described by way of metadata using

Which Metadata we need? Course has:

Learning goals

Schedule of learning activities (assignments, discussions)

Registered participants (teachers, students)

Different types of resources

We usually can extract such information from LMS, but how it is possible in case of PLE?

Formats for PLE metadata

(X)HTML is a main format for PLE

(X)HTML syntaxes are not designed for carrying the semantic data

Different technologies were introduced in the past

Microformats and RDFa are two most widespread

Scenario

Teacher publishes a Course’s information by using a web application — blog, wiki, forum or personal web site

Information by means of mash-ups is delivered to learners

Scenario: Data

The Course can contain:

(meta)data about the course syllabus,

pre-requisite and target competencies,

amount of credits,

dates for start and end of the course,

the criteria and form of a final assessment,

contact information of teachers and other participants

Scenario: Features

Teacher can constantly update the course information during time

Teacher assigns lectures, announces an assessment and evaluates learners

Learners thus constantly have the fresh information on everything that happens on a course

Microformats

HTML code:

<a href = "http://creativecommons.org/licenses/by/2.0/" rel="license">cc by 2.0</a>

In browser:

cc by 2.0

Microformats

Standard (X)HTML attributes 'class', 'rel' and 'rev' are used for metadata storing purpose

Not standardized, but well specified and widely known

Endless development

Have no ontologies, formal descriptions or schemes

RDFa

HTML code:

<a rel="cc:license" href="http://creativecommons.org/ licenses/by-nc-nd/3.0/"> Creative Commons License </a>

In browser:

Creative Commons License

RDFa

Standardized by W3C

Uses 10 reserved tags, 5 of them from XHTML2

Can be applied for RDFa only to XHTML2, not for HTML, XHTML1

Mixing different namespaces in one document is possible, for example 'dc:' and 'cc:' simultaneously

Hard to suppose prospect because of end of XHTML 2 support from W3C

Technological Comparison

Microformats

RDFa

Can be applied to HTML, XHTML In current state for XHTML 2 and limited for XHTML 1

Have useful implementations for end user today

Yes, different add-ons for browsers allow that

Not very useful for end user directly today

Can be used in mash-ups Yes Yes

Practice using for semantic indexing examples

Google and Yahoo now indexing such microformats as hCard and hReview

Google, US Government Website and Slideshare use RDFa

Standardized No W3C Recommendation

Drawbacks One limited dictionary for all purposes.Because of absence of standards support from developers is more enthusiastic than industrial

Because of finishing of XHTML2 development the perspectives of RDFa are very unclear at the current moment

Semantic Comparison

Microformats

RDFa

Vocabulary Only one Unlimited amount is possible

Vocabulary can be extended

Yes, but only through community

Yes, freely

Interoperability level High Interoperability is possible only if known vocabularies are used

Possibilities to add semantic value to data

Average High

Application for educational needsMicroformats RDFa

Course’s membership via hCardLearner and Teacher information via hCardMembers relations via XFNCourse events via hCalendar

Can use any semantic vocabulary that suitable for course description

Implementation on Wordpress

Vladimir Tomberg, Mart Laanpere

Towards Lightweight LMS 2.0: A Blog-based Approach to Online Assessment,

EC-TEL 2008 Maastricht, The Netherlands

Under development at present

Conclusion

Which technology is more suitable?

Microformats

Good simplicity of adaptation to web;

Limited vocabulary for educational needs;

RDFa

More flexible and semantically rich;

Unclear prospect because XHTML2 developing is stopped