Learning Object Models and an e-Learning Service Infrastructure for Virtual e-Learning Communities

Multimedia data and application systems accessible over the Web are valuable assets for developing instructional materials for teaching, training, problem solving, and decision support. These assets can be used to construct learning objects, each of which is a reusable granule of instruction designed to meet a specific instructional objective. In order to find and use learning objects, an infrastructure for the registration, discovery, binding, and invocation of these objects is needed. Also, there is a need for an e-learning service infrastructure for people in a virtual e-learning community to construct, evaluate, and deliver learning objects. In this work, we model distributed and sharable learning resources by two types of Learning Objects (LOs): Atomic Learning Object and Composite Learning Object. Both types of LOs are published uniformly as Web services in a constraint-based broker in order to make them sharable and reusable. This article presents the learning object models for the specifications of these two types of LOs and an e-learning service infrastructure, which consists of authoring tools for constructing LOs, software components for processing LOs and performing assessments, and an extended Web services framework for the registration, discovery, binding, and invocation of LOs as Web services. This article also presents techniques such as dynamic binding of LOs, rule-based execution of learning processes, and modelbased assessment used to make the processing of LOs active, flexible, customizable, and adaptive. The roles and functions of virtual e-learning community members are also discussed.