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CHIEN-TSUN CHEN, YU CHIN CHENG, CHIN-YUN HSIEH AND TIEN-SONG HSU
Department of Computer Science and Information Engineering
National Taipei University of Technology
Taipei, 106 Taiwan
Service-oriented architecture (SOA) is increasingly popular for constructing eLearning
systems. SOA encourages the separation of process from underlying services. The
separation is also advocated by IMS Learning Design, an international standard for describing
a learning process. Despite the apparent congruence and the recent proposals of
several SOAs for eLearning, existing eLearning systems have yet to take full advantage
of the process-service separation and are denied of a number of quality attributes promised.
In this paper, we describe a new approach, which incorporates process translation
and a three-layer SOA, for delivering specification-based eLearning processes. Specially,
an eLearning course description specified in IMS Learning Design is translated into a
process of Business Process Execution Language (BPEL). The translated BPEL process
is then executed on a BPEL engine, which powers the process service layer of the SOA
and keeps the learning processes separated from the underlying Web services. The architecture
achieves extensibility, reusability, and ease of integration by allowing advanced
eLearning standards to be incrementally implemented as a group of collaborating processes
in BPEL. Translation rules from IMS Learning Design into BPEL are presented.
The benefits of the proposed approach are investigated and compared with existing
eLearning architectures.
Received November 5, 2007; accepted July 29, 2008.
Communicated by Jonathan Lee, Wei-Tek Tsai and Yau-Hwang Kuo.
* This work was supported in part by the Ministry of Economic Affairs of Taiwan under the grants No. 95-EC-
17-A-02-S1-029 and 96-EC-17-A-02-S1-029. We thank Meng-Che Chen for his participation in implementing
the system.