Engineering Commons^™

Wavelength Drift In Cwdm Systems: Impact And Measurement, Thomas Freir

Masters

The research begins with an investigation of wavelength drift in Coarse Wavelength Division Multiplexing (CWDM) systems, especially in the context of temperature dependent wavelength drift. A simple model was proposed using a typical ‘application’ from ITU-T G.695. OptiSystem was chosen as the simulation platform due to its ease of use, the variety and flexibility of its inbuilt components and similar models simulated on the platform in the past. The research then investigates the measurement of wavelength drift focusing on how to determine an acceptable wavelength accuracy for a CWDM wavelength monitor. The chosen approach arose from observations of the results …

Antenna Designs For Wireless Medical Implants., Conor P. Conran

Masters

Active medical implants are devices that are surgically implanted inside the body. They have been developed to treat a wide range of ailments and many require some form of communications link with the outside world for maintenance and for remote medical diagnostics. Radio links promise a wide range of benefits over the traditional low frequency inductive coupling method.

Body tissue is a challenging environment, both for the device and for the radio signal that it transmits. Innovation in medical technology is creating a demand for high bandwidth links, and this in turn is driving the development of implantable antennas.

Many …

The Unprecedented Assimilation Of Mobile Telephony In Ireland: A Phenomenon Of The Celtic Tiger Era Or A Result Of Cultural Traits?, Andreas Scheibelhut

Masters

Following the universal acceptance of mobile telephony the once elitist gadget has become an indispensable democratic tool of everyday communications over the last three decades. Controversially, this thesis illustrates that its level of both adoption and usage did not develop in a similar homogenous pattern in selected OECD countries. In particular, the Irish performance is rather astonishing given the speed of adoption as well as the exceptional high revenue figures achieved by the wireless operators. Consequently, this work determines a selection of factors that drive and encourage both the adoption and usage of cellular telephony in Ireland. The Irish experience …

Monitoring And Regression Based Modelling Of End Winding Vibration In Large Synchronous Generators., David Shally

Masters

This research project was set up to monitor, on an ongoing basis, the condition of the end windings and their support structures of a 288 MVA 2-pole synchronous generator with a known end winding vibration problem Excessive vibration at the end windings was caused by the natural frequencies of individual end bars (local) and of the entire end winding structure (global) being at or close to the magnetic forcing frequency of 100 Hz. Resonant vibration such as this has been a cause of major failures in machines of the same type in the past, resulting in significant down time ranging …

Meshscan: A Fast And Efficient Handoff Scheme For Ieee 802.11 Wireless Mesh Networks, Yin Chen

Masters

As a next generation network solution, Wireless Mesh Networks (WMN) provides fast Internet access to a large area, which is from university campus to city scale. In order to provide an uninterrupted Internet experience to a mobile client, a process called handoff is required to maintain the network connection from one Mesh Node (MN) to another MN. Ideally, handoff should be completely transparent to mobile users. A critical application like VoIP will require a handoff capability that transfers a call from one mesh node (MN) to another in less than 50 msec. However the current IEEE 802.11 standards do not …

Blind Single Channel Sound Source Separation, Mark Leddy

Masters

In recent years source separation has become an increasingly popular area of research in the signal processing community. The subject has found applications in a variety of fields such as medical imaging, sound and audio, econometrics and geophysics. This document will discuss the application of source separation techniques to the area of audio. Sound source separation is the process of observing a mixture signal made up of a number of sources, and from this mixture estimating the individual source signals. Audio source separation techniques may be crudely split into the following areas; techniques that utilise attributes of the sources, and …

A Mobile Ecg Monitoring System With Context Collection, Jin Peng Li

Masters

An objective of a health process is one where patients can stay healthy with the support of expert medical advice when they need it, at any location and any time. An associated aim would be the development of a system which places increased emphasis on preventative measures as a first point of contact with the patient. This research is a step along the road towards this type of preventative healthcare for cardiac patients. It seeks to develop a smart mobile ECG monitoring system that requests and records context information about what is happening around the subject when an arrhythmia event …

Wideband Dual Polarized Directional Base Station Antenna, Francisco L. Lerma

Masters

The thesis presents a study of different microwave radiators for wireless applications in the frequency range of 2.2 – 2.5GHz. The performance of microstrip patch antennas and dual polarized dipole antennas were evaluated numerically and experimentally verified. A single microstrip patch and a four- element microstrip array were simulated, fabricated and tested. Simulation was carried out by the finite integration time domain (FITD) method. Polarization diversity is realised using crossed dipoles printed elements. For the crossed dipole elements, two different feed arrangements were studied. Parameters such as return loss, isolation, radiation pattern, gain and bandwidth were measured and found to …