Diver navigation system acoustic signal encoding/decoding optimisation

This thesis describes the optimisation of the encoding and decoding processes used to transmit and receive frequency coded data tones acoustically during the operation of an underwater diver navigation system. The aim was to reduce the time required to both generate these data tones for transmission as well as to decode these tones during reception. Encoding of the data tones is performed using a phase lock loop under the control of a microcontroller. A technique was developed which combined both hardware and software modifications to effectively halve the phase lock loop settling time, and therefore the time required to generate these tones. Decoding of these data tones is achieved using the Fast Fourier Transform. Alternative forms of the Discrete Fourier Transform were explored to find the most efficient in terms of execution time. Numerous software optimisations were then applied which led to a reduction in program execution time of 54 % with no penalty in program complexity or length. Testing of the system under identical real-life operating conditions showed no evidence of any system performance degradation as a result of these optimisations.

Low cost underwater robot sensor suite

One of the most expensive parts of underwater robotics is the sensors. This paper looks at modifying off the shelf components to create a sensor suite on a small budget. A big saving is made with sonar using a cheap commercial product to create a four sonar array. A depth sensor and acceleration navigation system are also developed.

A classification for content adaptation system

Content adaptation is an attractive solution for the ever growing desktop based Web content delivered to the user via heterogeneous devices, in order to provide acceptable experience while surfing the Web. Bridging the mismatch between the rich content and the user device's resources (display, processing, navigation, network bandwidth, media support) without user intervention requires a proactive behavior. While content adaptation poses multitude of benefits, without proper strategies, adaptation will not be truly optimized. There have been many projects focused on content adaptation that have been designed with different goals and approaches. In this paper, we introduce a comprehensive classification for content adaptation system. The classification is used to group the approaches applied in the implementation of existing content adaptation system. Survey on some content adaptation systems also been provided. We also present the research spectrum in content adaptation and discuss the challenges.

Contextual navigation in a multimedia journal

This work presents a framework for multimedia journaling,maintaining strong relationships between the document and embedded media. This enables media archives that are robust to changes in software environments, such as changes in web-sharing services, proprietary file formats and enables portability across operating system. We develop a journaling application using an existing multimedia framework, and show the power of the paradigm with specific case studies.

A visual language and environment for enterprise system modelling and automation

Objective: We want to support enterprise service modelling and generation using a more end user-friendly metaphor than current approaches, which fail to scale to large organisations with key issues of "cobweb" and "labyrinth" problems and large numbers of hidden dependencies. Method: We present and evaluate an integrated visual approach for business process modelling using a novel tree-based overlay structure that effectively mitigate complexity problems. A tree-overlay based visual notation (EML) and its integrated support environment (MaramaEML) supplement and integrate with existing solutions. Complex business architectures are represented as service trees and business processes are modelled as process overlay sequences on the service trees. Results: MaramaEML integrates EML and BPMN to provide complementary, high-level business service modelling and supports automatic BPEL code generation from the graphical representations to realise web services implementing the specified processes. It facilitates generated service validation using an integrated LTSA checker and provides a distortion-based fisheye and zooming function to enhance complex diagram navigation. Evaluations of EML show its effectiveness. Conclusions: We have successfully developed and evaluated a novel tree-based metaphor for business process modelling and enterprise service generation. Practice implications: a more user-friendly modelling approach and support tool for business end users.