ERDRM: A Digital Rights Management System Model for Educational Resources 75 4 The ERDRM System Model Based on the previous sections, this section brings forth the ERDRM, a digital rights management system model for educational resources. 4.1 Functional Components of the Model Educational resources is based on a collection of files, including text, images, video and other multimedia formats, but most of the formats cited above can be expressed by HTML files, and HTML, GIF and JPG are common formats used in learning ob- jects. Our system applies C/S infrastructure. There are server-side and client-side in this model. The server provides three services: content packaging, licensing manage- ment, content distributing. The core of Client is the trusted Add-on, which is in charge of the requesting and executing of rights. Fig. 2 describes the functional components in detail. Trusted Add-on License Manager The third party License Manager Access Control Packager Licenses management DB User/role Info DB Learning Objects Repository Content Repository Request/Licensing portal Web Explorer Content Packaging License Management Resource Distribution Server Client Fig. 2. The model’s functional components Content Packaging. This module includes learning objects repository and packager. Granularity is a key issue must be considered in the protection of resources. This model encrypts and protects the content in denomination of learning object. The educational resources to protect are stored in the learning objects repository. The packager encrypts 76 S. Wang and Q. Liu and packages the educational resources, and sends to users along with the metadata. It also creates the rights, keys and other information which will be delivered to license management module. License Management. This module includes license manager, license management DB, and the 3rd party license manager. It is mainly used to receive the request comes from client, create and distribute license. License is a computer file consists of permissions, keys and information about the author and distributor. Enlightened by Osvaldo’s work [11], we use the third party license manager because of the reusable features of educational resources. If the learning object is aggregated with another object and that one was protected, the third party license manager works. Resources Distribution. This module includes user/role information DB, content repository, and access control, as well as a request/licensing portal. It handles the user authentication, access control policy, education resource distribution and financial business. Client. This is a web explorer which contains a trusted Add-on. It helps users to access and use the educational resources. The trusted Add-on collects users’ identities and other information, controls the usage of the content. If no license is found, it will make a license request to license manager. 4.2 Expression, Control and Implementation of Rights Expression, control and executing of the rights information flow are very important in DRM. As mentioned in section 1, both XrML and ODRL are XML-based and they have been accepted by several standards organization. XrML is perfect but complex, its parser is bulky and takes long time to download and run. XrML is protected by patents. All these make it is far from a suitable REL for educational resources DRM systems. On the other hand, ODRL has been a standard of OMA’s mobile DRM rights expression language. COLIS, OPENIPMP and many other projects have ap- plied ODRL as an REL. In our model, we still apply ODRL as reference REL. 4.3 DRM System on e-Learning Platform Digital rights management of educational resources is part of the e-Learning platform, so it has to integrate seamlessly with the other systems, such as learning management sys- tem, learning content management system and resources management system (Fig. 3). All entities in DRM-enabled e-Learning platform have to support the expression, management and control of the learning object’s rights information. Learning object’s rights information flow exists in the whole lifecycle. A simple example, learning con- tent management system gain educational resources with rights attributes from re- sources management system, and delivered them to learning object exchange system in security, the DRM system protects the learning objects to be distributed and add rele- vant authentication and rights information on them, then learning management system manages the license and permissions. The user accesses and uses protected learning objects while he or she participates in the activities of learning management system as authorized. The user can reuse the learning object to create a totally new learning object. ERDRM: A Digital Rights Management System Model for Educational Resources 77 Modules in a whole e-Learning platform have all kinds of interactions, which isn’t limited to the situations mentioned above. In DRM-enabled e-Learning platform, DRM system works on the Parties directory, learning object exchange system and learning management system. In a broad sense, all entities have participated in the implementation of digital rights management. Learning Management Learning Content Management Resources Management Learning Object Exchange Parties Directory Reuse Rights Tracking Permissions Management Secure Delivery Rights Attribution Rights Validation Content Source Content Use DRM direct acting areas DRM System Fig. 3. DRM-enabled e-Learning platform 5 Conclusion Many e-Learning organizations and high schools have attempted to apply DRM tech- nology in web-based education, but most of them focus on rights expression language and the standards. There is no real mature solution for the realization of digital rights management. By analyzing the education’s particular demands on digital rights man- agement, we proposed a digital rights management system model for educational re- sources. We studied the expression, control and execution of rights and the relationship between DRM system and other systems on e-Learning platform in section 3. Our next work is developing the product system based on the model. Many of these open issues and problems are intertwined and will require an integrated approach to be satisfactorily resolved, and this is the work we should make great efforts in the future. Acknowledgments. This paper is supported by NSFC of China (NO.60673010), partly supported by National Great Project of Scientific and Technical Supporting Programs Funded by Ministry of Science & Technology of China During the 11th Five-year Plan (NO. 2006BAH02A24), and supported by the Natural Science Foun- dation of Hubei Province (NO. 2006ABC011). 78 S. Wang and Q. Liu References 1. Yu, Y Y., Tang, Z.: A Survey of the Research on Digital Rights Management. Chinese Journal of Computers 28, 1957–1968 (2005) 2. Erickson, J.S.: OpenDRM: A Standards Framework for Digital Rights Expression, Mes- saging and Enforcement (2002), http://xml.coverpages.org/EricksonOpenDRM20020902.pdf 3. Erickson, J.S., et al.: Principles for Standardization and Interoperability in Web-based Digital Rights Management: A position Paper for the W3C Workshop on Digital Rights Management (2001), http://www.w3.org/2000/12/drm-ws/pp/hp- erickson.html 4. 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(Eds.): ICWL 2008, LNCS 5145, pp. 79–86, 2008. © Springer-Verlag Berlin Heidelberg 2008 Course Material Research Based on Perti Net Kun Xiao 1 , Shihong Chen 1,2 , and Xi Chen 1 1 School of Computer, Wuhan University, Wuhan Hubei 430072, China 2 National MultiMedia Software Engineering Technology Research Center, Wuhan University. Wuhan 430072, China zfsnxk@yahoo.com.cn,chen_lei605@sina.com,chen_xi@163.com Abstract. Many designers pay much more attention to establish an e-learning system but ignore to judge what material is proper for courseware merger. This paper tries to realize it via the Petri net. The relationship between material and knowledge point (KP) is closely. So, in order to use the Petri net, it presents the relationships among KP as the net firstly. Based on the relationships among KP, It analyzes the relationships among material in detail and brings forth the mate- rial sets (MS) net. And then, it gives the formalization description of the mate- rial Petri net (MPN) based on the Petri net (PN) and provides the method of the transformation from the MS net graph to MPN. When material is merged into the courseware, some speciality of material can be checked by the MPN. The experiments shows that the MPN can validate the reasonableness of the material merger effectively. Keywords: Petri net, material, courseware. 1 Introduction The syllabus consistes of some knowledge point (KP), and KP may be reflected in the different types of material. The method, which puts material and KP together, aids teacher to organize the individual courseware automatically. Some researchers concern the researchs of the KP[1, 2, 3], others concern the construct of e-learning[4, 5, 6]. They have the good idea of utilizing e-learning[7, 8]. However, many intelligent tutor systems organize the material into a suitable special courseware ineffectively. Although the KP is in closely connection with the material, the KP and the material have a lot of different still. The KP in the syllabus is always reflected in some material, and the material al- ways reflects some KP. When the material is discussed, the relationships between the material and the KP must be concerned together. If we ignore this point, we would have difficulty to validate some cases. • When the courseware is designed, any KP reflected in the material in the course- ware does not excess the scope of the syllabus. • If the material is learned in the courseware, it must reflect in one or more KP in the syllabus. • the material taught at the earlier stage does not use the KP reflected in material taught at the latter stage. . Controlled Digital infor- mation Dissemination. In: The Proceedings of the 16th Annual Computer Security Appli- cations Conference, pp. 224–233. IEEE Computer Society Press, Washington (2000) 11 Educational Resources 77 Modules in a whole e-Learning platform have all kinds of interactions, which isn’t limited to the situations mentioned above. In DRM-enabled e-Learning platform, DRM system. learning object exchange system and learning management system. In a broad sense, all entities have participated in the implementation of digital rights management. Learning Management Learning