Web services to allow access for all in dotLRN German Moreno 1 , Olga - PDF document

Web services to allow access for all in dotLRN German Moreno 1 , Olga C. Santos 2 , Jesus G. Boticario 2 , Ramon Fabregat 1 1 Institute of Informatics and Aplications (IIiA), Universidad de Girona, Spain, gmoreno@eia.udg.es, ramon.fabregat@udg.es, http://bcds.udg.es/ 2 aDeNu Research Group, Artificial Intelligence Department, Computer Science School, UNED, C/Juan del Rosal, 16. 28040 Madrid, Spain {ocsantos, jgb}@dia.uned.es http://adenu.ia.uned.es/ Abstract. This paper describes a proposal for implementing the "Access for All" initiative by ISO in dotLRN being developed in the context ADAPTAPLAN project: ” Adaptation based on learning, modeling and planning for complex tasks oriented to the user” . As a result, dotLRN will be able to match access individual learner preferences and needs with the appropriate user interface tools and digital learning resources. This will involve the following developments. First, some graphical user interfaces to allow the user to define 1) her accessibility preference in terms of ISO Personal Needs and Preferences standard, and 2) the accessibility features of the contents provided (both those provided by the course designer at design time and a course member who wants to share her contributions at runtime) in terms of ISO Digital Resource Description standard. Second, a set of web services to allow dotLRN retrieve this information (users ’ PNP attributes and contents ’ DRD metadata) in order to select the most appropriate contents for the user. Keywords: Web Accessibility, dotLRN, Educational Standards, Web Services, Learning objects, User Models. 1 Introduction Nowadays, Web Inaccessibility is one of the problems that have caused more interest in the European Union due to ethical, economical and social factors. In October 2003, the European Union launched the Plan “Equal opportunities for people with di sabilities” [1] to increase awareness on disability issues and established networks through different projects. It introduced a multi-annual action plan running until 2010. One of the key objectives of this plan is to improve accessibility for everyone. This included the need to remove all barriers that impeded the full participation of disabled people in the information society. The current proposal was developed in the context ADAPTAPLAN project: ” Adaptation based on learning, modeling and planning for c omplex tasks oriented to the user” [2]. . In the same vein, Web accessibility aims that people with disabilities can perceive, understand, navigate, and interact with the Web, and that they can contribute to the Web. Different approaches have been developed for achieving this objective. One comes from the “Access for All” standard of the International

Organization for Standardization (ISO) [3]. This initiative promotes the use of the strategy of personalization by using the adaptation process as a universalizing element. The idea of this approach is twofold. First, allow the user to define her preferences with respect to the content, display and control of the information. Second, describe the relationships between resources and their transformation possibilities. In this way, it is possible to select, modify or transform a resource to make it accessible to every person at the time of access. The Adaptive Hypermedia Systems (AHS) [4] aim to improve the usability of hypermedia applications by making them personalized. The Web services support the creation of dynamic and shareable frameworks for automated adaptation. In this paper we propose to implement the ISO “Access For All” Standard in the dotLRN [5] Learning Management System. The idea is to design and implement each of the components proposed in the “Access For All” Standard in light of the Adaptive Hypermedia Systems framework, and decouple the implemented models through Web services. The background of key topics such as: ISO “Access For All” Standard, Adaptive Hypermedia Systems and Web Services are briefly described in the section two. Then, a proposal overview is presented, focusing on key elements for its implementation. Finally, a discussion about the effectiveness of education technologies related with this proposal is presented. 2 Background 2.1 The ISO "Access For All" Standard The ISO "Access For All" Standard [3] aims to facilitate the discovery and use of the most appropriate content for each user. At the time of writing this article the standard consists of eight parts, of which the first three form the basis of current proposal. The first part describes a framework and reference model for accessibility for everybody [6]. The second part defines the information model to describe the personal needs and preferences (PNP) [7] for accessing digital resources, and the last part defines the information model to describe digital resources (DRD) [8] according to their access modes. In Figure 1 we can see a representation of an abstract model of the parts described in the ISO "Access For All" Standard. In this model a person or agent declare their access needs and preferences to digital resources through a PNP statement. The resources are characterized by defining its access modes through a DRD statement. In the Figure 1 we can also note that a PNP statement is made up of control and presentation preferences and of contextual and accessibility descriptions of digital resources. For its part, a digital resource DRD statement comprises a description of accessibility to itself and relationships to other alternative resources. We can see that the PNP and the DRD use the same abstract model for defining their accessibility features.

Fig. 1. Access For All Abstract Model [6] The ISO “Access For All” Standard attempts to f acilitate the correspondence between the needs and preferences of individual users and the educational resources. This standard is designed to address the nonconformities between personal needs and preferences caused by any circumstance including requirements related to the customer´s devices, environment, knowledge and language skills. 2.2 Adaptive Hypermedia Systems (AHS) The core strategy in an AHS is to know the specifics of who uses the system and thus be able to offer a material according to their characteristics in a specific domain. Paul De Bra in [9] defined a reference architecture for developing AHS, called Adaptive Hypermedia Systems Architecture (AHA). AHA has three models: the User Model, the Domain Model and the Adaptation Model. Using these models plus a mechanism for adaptation, an AHS can be developed. - User Model (UM): Stores the user characteristics that the system takes into account to make adjustments. Often includes user awareness on concepts in the domain model. - Domain Model (DM): Describes how to link and to structure the domain information in terms of fragments, pages and concepts which can be abstract or not. - Adaptation Model (AM): Defines how the stored information in user model affects the adaptation of the system. It also specifies how and when to update such information.

2.3 Web Services Web Services are software systems which provide standard ways to interoperate between various existing applications run on heterogeneous resources or frameworks [10]. They have been designed to wrap existing applications and expose them using an interface described in machine-processable format such as Web Services Description Language (WSDL)[11]. Other systems can interact with web services using Simple Object Access Protocol (SOAP) [12] messages. Web Services can be described as loosely coupled, reusable software components, which can be orchestrated on the fly. 3 Proposal Overview The proposed system has basically three goals on the dotLRN system. The first goal is providing dotLRN users a way to define their access needs and preferences through the ISO PNP standard. The second one is giving dotLRN content producers a form for characterize and structure the access to digital resources using the ISO DRD standard. Finally, the proposed system will also allow dotLRN to deliver its users resources tailored to their access needs and preferences through the Web services. Figure 2 illustrates the proposed system architecture. User Format_1 Model Transformation Service PNP Repository Service Use User Profiles Use Web “Access Format_2 “Access For All” request For All” dotLRN Transformation Service Use “Access For All” response Service (Adaptive Engine) ... Resource Metadata Use Use Domain Format_N Model Transformation Service Service DRD Repository Fig. 2. Proposed System Architecture In order to promote reusability and sharing of information models, the proposed system will be composed by three services based on an AHS framework: - User Model Service: responsible for structuring, linking and storing the various PNP of a user on a specific repository (in our case we use Fedora Commons Repository [13]). This service allows making queries about managed PNP of a specific user.