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Mobile Topic Maps for e-Learning
John McDonald & Darina Dicheva Intelligent Information Systems GroupComputer Science DepartmentWinston-Salem State University, USA
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
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
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
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
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
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
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
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
TM4L-ME Architecture: TmNugget
TM4L-ME Architecture
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
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
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
TM4L-ME Architecture:
Mobile Device
Topic Maps For e-Learning (Mobile Edition) (TM4L-ME)
J2ME
Web Service Client
XML Parser
Topic Map Server
Topic Maps For e-Learning (TM4L) (TM Server)
JavaApache Axis / Web Service
TM4J
Topic Map Nugget(TmNugget)
XML
TM4L-ME API
Topic Map Repository
TM4L-ME Implementation
Developing the prototype Eclipse Development environmentJava Micro-Edition 2 (J2ME) platform
Device Simulators Ant Build Tools Apache Axis Jakarta Tomcat Blackberry development toolkit
Blackberry Simulators Build Tools
TM4L-ME Implementation (cont’d)
TM4L-ME Server (Web Service)Java ImplementationBuilt using Apache Axis Interacts directly with TM4L APIHandles TmNugget distribution
TM4L-ME Implementation (cont’d)
Mobile ClientTargeted the Blackberry
platform Good user base Keyboard, scroll mouse Mature development tools
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.