Introduction

Web services have become known as a powerful interoperability solution, mostly mentioned in the context of business-to-business (B2B). Web services allow "application to application communication". World Wide Web Consortium's Web services Activity Statement claims the following: "Programmers can use different operating systems, programming languages, etc., and have their software communicate with each other in an interoperable manner."

Two major players of the IT field, Microsoft and Sun Microsystems, have come up with Web services solutions. Where Web services themselves ride on independent components, the decision about using .NET (MS) or J2EE (Sun) is merely about in which application development environment Web services will be deployed (1). There is a lot of standardisation work starting and already going on in the Web services area, whereas industry is moving ahead in a fast pace setting up their own specifications (2).

Web services in the Educational Community

Like any other inventions on the Internet, sooner or later Web services will arrive to the domain of learning technologies to ease the pain of managing a multitude of different eLearning applications, and to make them play together, hence achieve higher level of interoperability.

The Ariadne Foundation runs a Knowledge Pool System (KPS) for learning objects. It has been testing and using Web services in their networks for about a year. Monthly Insight to Interoperability had a chance to talk to Prof. Erik Duval, chairman of the foundation.

Riina: In the first place Web services were not developed to help exchange and reuse of learning resources. What tricked Ariadne to look into Web services?

Erik Duval: SOAP and Web services are, most of all, a question of interoperability for Ariadne. To have an open infrastructure for learning one needs two things, which could be labeled as "What and How".

"What" comprises agreements and standards on the objects you want to exchange, it could be user profiles, LOs, metadata, what ever you find relevant to exchange in your context.

"How" is "How are you going to get these things?" i.e. in this context we are talking about Web services, the state-of-the-art based on a XML structure, and the use of SOAP.

SOAP stands for Simple Object Access Protocol, it is "an XML based protocol for exchange of information in a decentralized, distributed environment." Mostly used in combination with HTTP and HTTP Extension Framework. http://www.w3.org/TR/SOAP/

Riina: Is Ariadne planning to extend experiences learned in their own use to the educational community?

Erik: Sure, and way beyond! There are plans to try to hook other Learning Object Repositories (LOR) together worldwide. A concrete example of this is the work carried out in the Learning Technologies Workshop (LTWS) under CEN/ISSS. A new work item has been introduced on "Interoperability of Learning Repositories", the goal is to take a step closer to a widely adoptable interoperability framework in this context.

Riina: To link Learning Object Repositories (LOR) worldwide, do you think it requires more of technical development than political lobbying?

Erik: The work on the practical level will show a good example. Rather than going around lobbying, I personally believe more in doing something so useful that people want to start using it. At the moment, when endusers start asking their own LOR "Why don't we have it, too?", I think the work has prove successful.

Riina: Hmm...actions speak louder than words..?

Erik: I do want to spend time on helping people understand what this is all about, that behind all the alphabet soup and abbreviations, we are not talking about very difficult issues. Demystifying, helping people to grasp a rough idea of what is going on, is also important.

Links:

Ariadne KPS Web services:
http://rubens.cs.kuleuven.ac.be:8989/ariadne/AWS/

Ariadne KPS Client:
http://rubens.cs.kuleuven.ac.be:8989/ariadne/KPSClient

Ariadne:
http://www.ariadne-eu.org/

World Wide Web Consortium (W3C)
http://www.w3.org/

Web services Activity Statement
http://www.w3.org/2002/ws/Activity

W3C on SOAP
http://www.w3.org/TR/SOAP/

CEN/ISSS Work Item Proposal:
Interoperability of Repositories for Learning
More info at: interoperability@alice.wu-wien.ac.at

SUN about J2EE:
http://java.sun.com/j2ee/

Microsoft about .NET:
http://www.microsoft.com/net/

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1) The Web Services Debate by Joseph Williams; J2EE vs. .NET: Communication of the ACM, June 2003/Vol.46, No6

2) Fulfilling the Web Service Promise by Heather Kreger: Communication of the ACM, June 2003/Vol.46, No6