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.