for managing these e-services as a whole, including the management of ... configuration management and application development process to manage current ...
An XML-based E-learning Service Management Framework Theodore K. Apostolopoulos Anna Kefala Department of Informatics, Athens University of Economics and Business 76, Patission st., 104 34 Athens, Greece Tel.: +30 210 8203234, 900, Fax: +30 210 8203909, E-mail: {tca,anna}@aueb.gr
Abstract The aim of this paper is proposing a flexible and component-oriented XML-based e-learning services management framework taking into account several parameters concerning the educational process, the network infrastructure, the QoS requirements, the available educational content, etc. Within this framework, a session profile is dynamically created for each request for e-learning service according to current context.
1. Introduction Every day new services deploy telecommunication infrastructure as a vehicle to reach new clients, located in distant areas. This evolution, leads to an emerging need for managing these e-services as a whole, including the management of underlying network infrastructure. One of the most popular e-services is that of e-learning [1] [2]. The proposed framework comprises a middleware which gathers all required information and performs the management of the whole e-learning service, including the communication between user and the e-learning server or the communication among distributed e-learning servers. Since e-learning is provided via network routes, we exploit experience gained from the area of network management. The management of IP networks has exclusively relied on Simple Network Management Protocol (SNMP). However, the SNMP management framework has some drawbacks especially related to configuration management and application development process to manage current huge networks. Lately, eXtensible Markup Language (XML) related technologies seem as a promising solution to this problem [4].
2. Proposed Middleware In the proposed middleware architecture [2], we consider an intermediate layer between some e-learning application and the underlying network infrastructure. Beyond its role as a facilitator for the cooperation between upper and lower layers, middleware is responsible for gathering all required information from the components comprising an e-learning system in order to manage the whole service. The upper layer of proposed architecture is
occupied by some e-learning application. There are no special restrictions regarding the characteristics of such an application. It will communicate with the middleware through specific Application Program Interfaces (APIs). When discussing about network infrastructure, two separate issues are on focus: Physical Network Infrastructure and Network-communication Protocols [1].
3. Design and Implementation Issues Many efforts of applying XML related technologies and their already existing implementations to wide range of e-learning systems are in progress. Major companies in networking area, such as CISCO or JUNIPER, deploy and support XML technologies in their systems and promote XML-based management. The XML Schema can be used to define the structure of management information in a flexible and efficient way. Widely deployed protocols such as HTTP, SSL, SSH or TCP can be used to transfer management data reliably. The DOM and SAX (Simple API for XML) are APIs that can be used to easily access and manipulate management data from applications, while Xpath expressions can be used to efficiently address the objects within management data documents. XSL can be used to process management data easily and generate HTML documents for a variety of user interface views. Web Services Description Language (WSDL) [6] and Simple Object Access Protocol (SOAP) can be used to define Web Services for powerful highlevel management operations. Since the proposed framework is based on the design and implementation of a middleware, we ought to adopt technologies that are standardized and widely deployed in both upper (e-learning system) and lower (network infrastructure) layers. Therefore, we are keen on adopting technologies based on standards, such as XML. The authoritative organization IMS (Instructional Management System) proposes the description of Learning Objects through an XML document validated with respect to an XML Schema established by the standard. This standard (also supported by the IEEE LTSC) is defined and supported by most of the commercial e-learning platforms [4]. The agents proposed in our management architecture are able to operate in e-learning contexts based on the LOM (Learning Object Metadata) paradigm according to IMS standards.
Proceedings of the IEEE International Conference on Advanced Learning Technologies (ICALT’04) 0-7695-2181-9/04 $20.00 © 2004 IEEE
XML-based Network Management (XNM) has been proposed as an alternative or to compliment existing SNMP-based network management, which has constraints in scalability and efficiency. XML provides powerful modeling features for structured management information in network management, XNM can transfer large amount of data over HTTP and can be implemented using standard APIs and freely available software [5].
4. Management Framework Having explored the advantages offered by the deployment of XML in management related issues, together with its wide deployment in e-learning systems, we propose an XML-based e-learning management architecture, as presented in Figure 1. The general architecture of the e-learning management scheme is based on the configurable component-based middleware architecture for deploying e-learning services presented in [1]. Each component has one or more agents, which maintain a local XML-based Management Information Base (MIB), and communicate with the manager, residing at the service or session management component. The agent accesses and manages its local MIB by using the capabilities offered from Xpath, Xquery and Xupdate. Xpath will be deployed in order to provide identification of particular sections of an XML document; while Xquery and Xupdate can provide many features, such as filtering XML-based MIBs, grouping management information, flexible updating of MIBs, etc. As far as the diverse underlying network technologies are concerned, there will be a corresponding XML-based MIB (Schema) for each different technology. Agents will communicate and cooperate with the manager, through a protocol such as SOAP or HTTP. SOAP is a lightweight protocol for exchanging information in a distributed environment. The choice of these communication protocols is apparent when considering that most elearning services are implemented using Internet technologies. A MIB is a conceptual representation of all resources that provide the manager with the ability to observe and control the current behavior of components and consequently of the whole e-learning service. The prime component is the one that creates dynamically the profile of a session for a requested service (Session Management Component) by taking into account several parameters in order to be open and flexible. Each of these aspects is regarded as a different component of the middleware in a view to meet requirements for flexibility and implementation simplicity. This is the component that undertakes the role of manager in our management architecture. Each component might be comprised by several objects. For every object certain properties are defined in order to describe required information (local MIB). One or more agents are associated with each managed component.
Figure 1: E-learning Management Architecture
5. Conclusions The presented e-learning service management architecture is a first approach to the implementation of the proposed e-learning service framework. We are currently working on the formal definition of MIBs based on the XML technologies. We also focus on standardisation issues concerning the implementation of such a management scheme. Future work will also explore formal ways of defining interactions, cooperation and communication among diverse components. Currently, we are in the process of designing and implementing a prototype of the proposed architecture.
6. References [1] T. Apostolopoulos, Kefala A., “A Configurable Middleware Architecture for Deploying E-learning Services” over Diverse Communication Networks, Proceedings of the IASTED CATE International Conference, 30 June–2 July, 2003, Rhodes, Greece. [2] T. Apostolopoulos, Kefala A., “An E-learning Service Management Architecture”, Proceedings of the 3rd IEEE ICALT International Conference, 9-11 July, 2003, Athens, Greece. [3] S-H. Cha, J-O. Lee, Y-K. Choi, K-H. Cho, “Implementing an XML-based Universal Network Management System in Java”, Lecture Notes in Computer Science, Vol. 2343, January 2002, 652-661. [4] A. John, K. Vanderveen, B. Sugla, “XNAMI-An eXtencible XML-based paradigm for Network and Application Management Instrumentation”, IEEE International Conference on Networks, September 28-October 1, 1999, Brisbane, Australia. [5] Z. Xu and A. Saddik, “A Web Services Oriented Framework for Wired and Wireless E-Learning Systems”, Proceedings of the Canadian Conference on Electrical and Computer Engineering (CCECE 2003), May 4-7, 2003, Montreal, Quebec, Canada. [6] J-H. Yoon, H-T. Ju, J-W. Hong, “Development of SNMPXML translator and gateway for XML-based integrated network management”, International Journal of Network Management, July 2003, Vol.13, Issue 4, 259-276.
Proceedings of the IEEE International Conference on Advanced Learning Technologies (ICALT’04) 0-7695-2181-9/04 $20.00 © 2004 IEEE
