1. Mobile Topic Maps for e-Learning John McDonald & Darina Dicheva Intelligent Information Systems Group Computer Science Department Winston-Salem State University, USA

2. Outline Mobile Computing in Education Ontology-aware e-Learning Systems The TM4L-ME Project  Design Topic map nuggets Support for topic map nuggets  System architecture TM4L-ME Server (Web Service) Mobile client Future Work

3. Mobile Computing in Education Dramatic growth in the mobile devices use  Becoming more popular than home computers  Outnumber personal computers 3 to 1 according to the Mobile Technologies and Learning Report Mobile web access suffers from interoperability and usability problems  W3C launched its Mobile Web Initiative (W3C MWI) m-Learning  Using devices that allow learners to have a high degree of flexibility in location and transport

4. Mobile Computing in Education (cont’d) Difference between e-Learning and m-Learning  Nature of connection between students and teachers  Device features: big differences between the output, input, memory and processing power requirements  Mobility of users and devices e-Learning always assumes network connectivity and sizable bandwidth m-Learning must account for limited connectivity and bandwidth

5. Topic Maps for E-Learning Ontology-aware e-Learning Systems  Imply shared understanding and consistency through the use of domain ontologies Ontology-based learning repositories: highly structured and interoperable  Topic Maps technology (XTM standard) allow semantic categorization of documents and the information contained within them TM4L (Topic Maps for e-Learning)  Enables creation, maintenance & use of ontology- aware courseware conforming to XTM Ontologies provide semantic interoperability; TM ensure syntactic interoperability  Plug-in architecture, free software

6. The TM4L-ME Project Goals  To create an extensible and reusable mobile environment for developing and using educational TM Remote browsing and editing of educational topic maps residing on a server from PDA devices Approach  To extend TM4L to a mobile computing platform Preserving TM4L functionality: adding, editing, deleting topics; inserting relationships between topics; repository browsing  Web service-based Utilizing web services to gain access to TM4L functionality

7. The Topic Maps Model Knowledge ‘elements’ classified into objects called topics Topics are related through associations (have types & define roles) Topics can be addressed by specific resources (occurrences) Topics, associations & occurrences can be scoped for different contexts

8. TM4L-ME Design Possible solutions  Converting the full version of the standalone TM4L to a J2ME (Java Mobile Edition) app Requires an extended focus on mobile device memory manipulation  Server-side TM engine & storage and a thin mobile client that could only ‘ask’ the server for the information about a particular topic Our goal also includes updating a TM from the mobile device  Client-server architecture with a thick mobile client that can host a small ‘chunk’ of the topic map; we coined the term Topic Map Nugget (TmNugget) TmNugget assists with handling device limitations

9. TmNuggets A TM nugget is defined around a center topic  Simplest case: consists of the center topic only  Can consists of the center topic along with all directly connected to it topics and the corresponding associations in the TM Typically, TM nuggets are defined to contain not only the center topic together with its direct neighbours, but also those topics that are indirectly connected to it (e.g. with a path of length 2, 3, 4, etc.  The allowed ‘depth’ depends on the available memory of the mobile device Definition:  A TmNugget for a specified topic ν and dept n (n = 1, 2, 3, …) is a sub-graph of the topic map graph, having a central point ν and eccentricity ε(ν) = n.  A TmNugget is represented in XML format: XTM extended with an additional element tmNugget

10. TM4L-ME Architecture: TmNugget

11. TM4L-ME Architecture

12. TmNugget Support Extracting a TmNugget with a specified center topic from the topic map  Involves finding a sub-graph of the TM graph with a specified center topic and depth Inserting or re-inserting a TmNugget back into TM  Implemented by applying the standard TM merge operation with appropriately set parameters Sending a TmNugget from the mobile server to a mobile client and from a mobile client to the mobile server  Implemented as a service

13. TmNuggets Communication Mobile clients request the TM Server for TmNuggets  Each request contains the device specifications and the ID of the requested TM  TM Server compares its specifications to a known list of mobile devices and acknowledges the device request  TM Server creates a unique session ID which allows the device to make subsequent requests without having to re-identify itself  TM Server creates the nugget  TM Server sends the nugget to the requesting mobile client

14. Creating TmNuggets To create a TmNugget, TM4L Server  Queries the TM repository to find the requested topic map  Links the located TM to the generated session id  Uses the requesting device specifications to determine the size (depth) of the TmNugget (if not specified)  Extracts the nugget with the specified center topic  Serializes the nugget to XTM format

15. TM4L-ME Architecture:

16. TM4L-ME Implementation Developing the prototype  Eclipse Development environment  Java Micro-Edition 2 (J2ME) platform Device Simulators  Ant Build Tools  Apache Axis  Jakarta Tomcat  Blackberry development toolkit Blackberry Simulators Build Tools

17. TM4L-ME Implementation (cont’d) TM4L-ME Server (Web Service)  Java Implementation  Built using Apache Axis  Interacts directly with TM4L API  Handles TmNugget distribution

18. TM4L-ME Implementation (cont’d) Mobile Client  Targeted the Blackberry platform Good user base Keyboard, scroll mouse Mature development tools

19. Future Work Evaluate TM4L-ME in an actual learning environment Continue adding features of TM4L to TM4L-ME by developing new Web Services As mobile device capabilities (memory, etc.) increase, expand mobile functionality.