Physical Sciences and Mathematics Commons^™

Performance Analysis Of Zero Trust In Cloud Native Systems, Simone Rodigari

Theses

Critical applications demand strong security implementations, low latency and high availability at constant rates, however, the performance of a software system is affected by the implementation of security. This research measures the performance overhead and possible mitigation in cloud native systems secured with a service mesh, which allows enabling security policies for the authentication, authorization and encryption of traffic within distributed systems. The side-car proxy is a core component of this architecture, acting as a policy enforcement point and intercepting networking communication from/to applications part of the mesh, consequently affecting the performance of applications hosted in the cloud. Physical resources …

Miniaturized Iii-V/ Si Hybrid Laser With An Integrated Modulator, Praveen Kumar Singaravelu

Theses

Light interaction with microscopic and nanoscopic structures enable manipulation of its characteristics which can be used to detect objects in 3D sensing, propel satellites to space using photonic propulsion and transmit data through optical communication. For optical communication, the basic components are lasers, modulators and photodetectors. The development of CMOS microfabrication foundries helps to manufacture silicon-based photonic devices with high yield that is directly co-integrated with electronics in a single chip. However, the lack of emission of photons efficiently in silicon propelled the necessity of hybrid photonic devices that inherits the combined advantage of different materials i.e. functionality and volume. …

Mos Compatible Deposited Materials For Optical Interconnects, Simone Iadanza

Theses

The recent years' exponential growth of data transmission in datacom and telecom technology (such as in Wavelength Division Multiplexing - WDM) has highlighted the energy consumption challenges of electronics, shifting research and industry interest towards optical interconnects. Novel and more efficient integrated photonics is being given the objective to face the ever-increasing demand for speed and bandwidth. This has initiated, in both industrial and academic environments, a quest for low-power, compact and cost-effective optical interconnects that can be integrated on electronic boards of Datacentres and transceivers all over the world. In this thesis, different types of WDM compatible Hybrid External …

Wavelength Swept Photonic Crystal Laser, Sharon Marie Butler

Theses

Photonics has become integral to society, based on its ability to sense the environment, to manipulate materials and to transport information. The dominance of silicon electronics has made silicon photonics a compelling vision, but difficulties with light emission have caused delays in implementation and an enduring role for III-V materials. The research conducted in this Ph.D. thesis involves study and utilisation of a combination of the optical gain of Indium Phosphide with the precision and energy of silicon nanophotonics in a novel family of lasers. A continuously tunable akinetic reflective filter is exploited to obtain a wavelength swept laser. The …

Development Of Analytical Methods For The Determination Of Β-Lactam Antibiotic Residues In Meat, Milk And Dairy Products, Melissa Di Rocco

Theses

In this project, analytical methodologies for the determination of β-lactam antibiotic residues in meat and dairy products were developed and validated using ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). The methods included the main penicillins, cephalosporins and carbapenems commonly employed in human or veterinary medicine for the treatment of bacterial infections. A multi-residue method for the analysis of 30 β-lactams was developed and validated in bovine muscle using dispersive-solid phase extraction (d-SPE), reversed-phase chromatography and mass spectrometry detection. A number of sorbent materials were assessed for clean-up, and a simple and straightforward sample preparation protocol developed for …

The Role Of Software Engineering In Bioinformatics, Brendan Sean Lawlor

Theses

This thesis proposes that by applying state-of-the-art software engineering tools, techniques and frameworks to currently recognised challenges in bioinformatics, improved outcomes can be attained in that field. It begins by decomposing software engineering into two categories, namely process and architecture, and choosing two key challenges in the practice of bioinformatics: reproducibility and scalability. The body of the thesis is an exploration of the intersection between these two software engineering categories and these two bioinformatics challenges. The question is asked: Can best practices in professional software engineering be applied to address key issues in the bioinformatics domain, creating positive outcomes? And …

Predicting Carcass Cut Yields In Cattle From Digitalimages Using Artificial Intelligence, Darragh Matthews

Theses

Beef carcass classification in Europe is predicated on the EUROP grid for both fatness and conformation. Although this system performs well for grouping visually similar carcasses, it cannot be used to accurately predict meat yields from these groups, especially when considered on an individual cut level. Deep Learning (DL) has proven to be a successful tool for many image classification problems but has yet to be fully proven in a regression scenario using carcass images. Here we have trained DL models to predict carcass cut yields and compared predictions to more standard machine learning (ML) methods. Three approaches were undertaken …

Photoluminescence Properties Of Novel Iii-V Semiconductor Systems, Shumithira Gandan

Theses

Perturbation of the inherent radiation equilibrium in solids by an external energy could engender an emission of the superfluous energy as electromagnetic radiation, or luminescence. Photoluminescence methods precipitate this disintegration of radiation equilibrium often by supplying the external energy as photons with energies higher than the bandgap energy of the solid. Since the excitation energy momentarily transforms the medium before luminescence is emitted, photoluminescence experiments are able to produce diverse and intricate spectroscopic data detailing the optical properties of the solid as a measure of this transformation. The pliability of allowed electron states in semiconductors have instigated bourgeoning research in …

Dynamics Of A Swept Source Laser Under External Injection, Uday Bangavadi Munivenkatappa

Theses

Swept Sources are lasers with a periodically modulated frequency, over a wide scanning range. They are widely used in Optical Coherence Tomography (OCT) for medical imaging and metrology. The narrow instantaneous linewidth of a swept source is required for longer OCT imaging depths. The goal of the project is to investigate the mechanism that deteriorates the coherence of a swept-source laser by analyzing its properties under external injection and investigate the possibilities for a phase-locked laser operation, in order to control the coherence properties. The laser under study was a semiconductor ring fiber-based cavity laser, incorporating a tunable narrow transmission …

Hybrid Frequency Modulated Silicon Photonic Crystal Laser, Andrei Bakoz

Theses

Silicon photonics takes advantage of the mature complementary metal-oxide semiconductor (CMOS) infrastructure and processes, and is actively pursued for the implementation of complex optical components and photonic integrated circuits (PICs) at low cost and high volumes. Despite a constant refinement of silicon photonics technology to meet the evolving requirements for applications, the poor light emission ability of silicon remains a constraint. As a result, the most essential building block of an optical system, an efficient light emitter, remains absent in PICs based on silicon. This thesis is focused on study of the potential of an external cavity (EC) hybrid III-V …

Development Of Uv Led Based Lamps With Modular Optical Heads, Ciara O'Hara

Theses

This project was centred around the development of the optical components, and the optimisation of the optical performance, of ProPhotonix Ltd’s Cobra Cure FX series of products. These are high irradiance, high dose, UVA (primarily 395 nm and 365 nm) Light Emitting Diode (LED) lamps designed for curing applications. An initial prototype developed by ProPhotonix, the smallest in the series, the FX1, underwent significant redesign throughout the project, and the two larger lamps, the FX2 and the FX3 were developed during the course of the project. This work primarily consisted in characterising, accurately modelling, and thereby refining, the optical reflector …

Passive Cooling In Non-Residential Nearly Zero Energy Buildings: A Thermal Comfort Analysis Based On Measurement, Modelling And Simulation, Adam O'Donovan

Theses

Overheating in non-residential nearly zero energy buildings (nZEBs) presents a major risk to the well-being, productivity and thermal satisfaction of the people who occupy them. As global temperatures are expected to increase in the future, the overheating risk and cooling demand is also expected to increase. Therefore, low cost and low energy solutions that are able to maintain thermally comfortable conditions without the need for mechanical systems will be vital in decarbonising the building stock and ensuring that buildings are comfortable and remain low carbon now and in the future. Passive cooling has long been championed as a low cost …

Dynamics Of Swept Source Lasers, Ben O'Shaughnessy

Theses

The aim of this thesis is to investigate the dynamics of two kinds of swept source lasers for optical coherence tomography. A mathematical model consisting of a pair of coupled delay differential equations was adapted to study Fourier Domain Mode-Locked (FDML) lasers and short cavity swept source lasers, and to explain experimental observations of these lasers.

The short cavity laser is experimentally observed to produce pulses during the frequency sweep. This ‘sliding frequency mode-locking’ behaviour is reproduced by simulation, which is then used to establish simple relationships between the key parameters of sweep speed, linewidth and output power.

The FDML …

Optical Properties Of Iii-V Nanowire/Nanopillar Lasers Grown On Si, Juan Salvador Dominguez Morales

Theses

Nanowires (NW) /nanopillars (NP) offer the possibility of reducing the mismatch of III-V semiconductor materials grown on different substrates such as Si, SiN, SiO2 and are hence being considered potential candidates for coherent light sources in optoelectronics technologies. The difference between NPs and NWs lies in the growth process. The NPs are site-controlled using a patterned mask, while the NWs use a self-catalysed such as gold or Ga-droplet.. In this dissertation, the emission properties of GaAs/AlGaAs (core-shell and core-multishell) and InGaAs (unpassivated and passivated with InGaP) nanolasers have been studied with excitation powers above and below the lasing threshold at …

Sub-Wavelength Gratings For Long Wavelength Sensing, Brian Hogan

Theses

This Ph.D. thesis is concerned with the design and use of guided mode resonance (GMR) reflectors for applications in optical absorption sensing at wavelengths around 10 μm. These grating based reflectors comprise appropriately designed optical nanostructures which resonantly reflect a wide range of incident wavelengths. Because of the periodic modulation of the refractive index in the grating layer, the guided modes which exist in this region leak out of the waveguide and arc more appropriately termed leaky or quasi guided modes. Resonant reflection occurs when phase matching of the incident light and these leaky modes cancels any transmitted light. The …

Development Of Multi-Class Analytical Methods For Agrochemical Contaminants, Sarah Tuck

Theses

In this project, cost-effective multi-class analytical methods were developed to detect a range of antiparasitic, feed additive and pesticide substances in foodstuffs of animal origin. These substances have the potential to enter the food chain through their occurrence as residues either through the animals themselves or other routes e.g. contamination. To ensure the continued safety of food destined for human consumption regulatory control limits have been established for permitted levels of these residues in foods of animal origin. Despite these controls the continued monitoring of foodstuffs is necessary to ensure these limits are not breached and that substances are not …

Predicting Energy And Water Consumption On Dairy Farms Through Statistical Analysis And Machine-Learning Methods, Philip Shine

Theses

With the abolishment of milking quotas across all European Union member states in April 2015, dairy farmers must adjust their farming practises to minimise milk production costs to adequately prepare for potential periods of reduced revenue. Milk production is an intense energy and water consuming process. Coupled with challenging European greenhouse gas reduction targets and legislation regarding the prevention of groundwater pollution and deterioration, increasing the production of milk in Ireland must be met with the sustainable consumption of on-farm energy and direct water resources, to ensure the future monetary and environmental sustainability of Ireland’s dairy industry. Thus, this body …

The Use Of Machine Learning To Detect Suckling In Pre-Weaned Calves, Sukumar Katamreddy

Theses

The weaning of cattle is a process which is known to be labour intensive and to have stressful effects on both cow and calf Common methods used in the weaning process include the temporary removal of a mother from the calf and manual observation and intervention. Early and speedy weaning is known to have a number of benefits, including health benefits for both cow and calf, additional weight gains for the calves as well as reduced labour and feed requirements. The process known as Two-Stage Weaning is recognised to be an effective low-stress approach to weaning in which the calf …

Novel Neuroevolution Techniques For The Life Science Domain, Timothy Manning

Theses

The life science domain is a high value research area, both in terms of the benefits in increased knowledge and in societal impact. Much of the research funding has focused on wet lab based approaches to increase visibility into biological processes and producing maximal relevant information on which to make decisions. Given the complexity of biological functions, in many cases this has led to an information overload. Researchers are now able to routinely generate and access petabytes of data as a result of high throughput experiments, and this capability is growing. This data can be difficult to interpret and intractable …

Development Of A Dynamic Cfd Model For Offshore Oscillating Water Columns With Non-Linear Interactions, Ken O'Connell

Theses

This thesis focuses on the development of a state of the art modelling technique for offshore Oscillating Water Column (OWC) type Wave Energy Converters (WEC) using Computational Fluid Dynamics (CFD). Current literature indicates a limited amount of work has been completed on studying these devices containing non-linear time dependent flow phenomenon. Initially, a 2D Numerical Wave Tank (NWT) is studied to reduce discretisation error in order to reproduce accurately propagating waves. Further development into a 3D domain permits the geometrical requirements of an OWC type spar buoy to be included.

In parallel, a single Degree of Freedom (DOF) model is …

Semiconductor Materials And Devices For 2 Micron Generation, Dzianis Saladukha

Theses

In the last century, semiconductor research has led to significant changes in the fields of communication, medicine, the environment, and many others. Semiconductor devices provide a relatively simple and effective way to convert electrical energy to light and vice versa. Devices based on semiconductor materials of various kinds provide interaction of an electromagnetic signal in the range of wavelengths with a medium. Examples of such devices are LED lamps, photovoltaic cells, thermometers, gas sensors, cameras, and many others. The study of various semiconductors broadens the range of application of photonics. This work is based on the study of materials which …

Intelligent Profiling Of Blood Donors In Ireland, Joanna Kossakowska

Theses

The demand for blood products in Ireland is constantly rising due to population growth and population ageing. It is believed that within the next decade these two factors will present challenges to blood donor recruitment and the availability of blood supplies. Improving the retention of blood donors will have a positive impact on the availability of blood products. Identification of suitable donors with the potential for long-term donating can potentially enhance the predictability of blood supply levels.

This research proposes that the patterns of blood donation behaviours of donors can be isolated from blood donor databases held by blood collecting …

An Application Of Time Series Methods To Investigate Eu Dairy Commodity Price Dynamics, Dennis Bergmann

Theses

Fundamental changes to the common agricultural policy (CAP) have led to greater market orientation which in turn has resulted in significantly changed price dynamics of EU dairy prices. These changed dynamics include sharply increased price variability of EU farm gate milk prices as well EU dairy commodity prices such as butter and Skimmed Milk Powder (SMP). In addition it was expected that EU dairy prices will align to Word dairy prices. This alignment of prices would also see an alignment of volatility levels which were significantly higher for World dairy prices than EU dairy prices. The aim of this thesis …

Exploration And Implementation Of Innovative Efficiencies/Devices In Beet Processing For Energy Production, Patrick Mcinerney

Theses

The imminent depletion of fossil fuels, as well as concerns for energy security and the obligation to respond to climate change has led to expanding worldwide popularity of Anaerobic Digestion (AD) of energy crops. Sugar beet is a popular AD feedstock due to its favourable characteristics; however it can be quite labour intensive requiring a range of specialist equipment to process the crop prior to undergoing AD. A crucial stage of this process involves the size reduction of beet by a mechanical chopper unit; this pretreatment breaks open the cellulose structure of the crop and increases the surface area available …

Real-Time Characterisation Of Dynamic Laser Fields, Thomas Butler

Theses

Many modern technologies rely on laser devices, in areas such as communications, sensing, and imaging. Examination and research into the fundamental operational dynamics of lasers, and characterisation of laser performance, are a crucial tool in ensuring the quality and effectiveness of laser-based applications. The development of characterisation tools is an important part of improving upon existing technologies and advancing the next generation of devices.

In this work, a real-time multiheterodyne detection technique is developed which allows for the study of dynamically varying pulse trains formed by optical frequency combs.

Development Of Nanoelectrodes For Electrochemical Applications, Séan Barry

Theses

The demand for direct, selective and rapid determination of chemical and biological analytes has led to a growing interest in electrochemical sensor devices. Particularly the use of nanomaterials and nanoelectrodes has received increased interest due to their enhanced electrochemical properties. In this thesis these enhanced properties are exploited in order to develop multiple sensing applications.

Firstly a sensitive microband based sensor is described for the detection of trinitrotoluene and for its discrimination from other nitroaromatic compounds. Square wave voltammetry was used to identify characteristic reduction peaks for these compounds and a calibration plot for the quantification of TNT was also …

Ultrashort Pulse Generation In Inas Quantum Dot Semiconductors, Patrick Finch

Theses

In this thesis, the effect of operating two-section InAs quantum dot passively mode- locked semiconductor lasers in the random population regime is examined in detail in an attempt to achieve wide optical bandwidths and ultrashort optical pulses. It is demonstrated in this work that large increases in optical bandwidths can be observed in the random population regime. Random population was achieved with an undoped device by lowering the operating temperature to 20 K. An emission bandwidth of 27 nm was measured using an undoped device at 20 K, with corresponding pulses of 290 fs, shorter than any previously reported with …

Cloud Practical Exam Invigilation Control Systems With The Objective Of Enhancing Quality Control For Online Exams, Gordon O'Reilly

Theses

Online cloud computing courses are becoming more common place facilitating a student to study from home from anywhere in the world. Coupled with this trend is a need for educational institutions to facilitate students to take tests or exams online from home. It reduces the remote student’s time and cost of travel to an exam invigilation centre as well as reducing the educational institution’s test administration overhead. It does however introduce potential quality control concerns. A new industry called online proctoring has emerged that attempts to provide quality control in these online test scenarios.

This research provides an insight into …

Low-Cost Fabrication Of Nanoelectrodes For Electrochemical Applications, Colm Barrett

Theses

Compared to traditional macroelectrodes, nanoscale electrodes have tremendous potential when employed in electrochemistry due to enhanced sensitivity arising from increased mass transport to the electrode and low background charging currents. Electrochemically- based diagnostic products such as sensors require sensing elements with greatly enhanced performance and nanoelectrodes offer a viable route to attaining this performance improvement.

Firstly, the fabrication of a polymer microneedle array-based sensor is described and employed to demonstrate a mediated approach for the detection of glucose in solution. This was to demonstrate the feasibility of the system for in-vivo sensing. Cyclic voltammetry was used to achieve detection of …

Emission Properties And Carrier Dynamics Of Iii-V Nanostructures For Next Generation Photonic Devices, Katarzyna Komolibus

Theses

A majority of modern day applications, ranging from telecommunications, charge storage memories and solar cells to more recently silicon photonics, have at their core compound semiconductor based optoelectronic devices. Particular attention has focused on the use of Group-III and Group-V elements in these devices and thus drives a desire for improved understanding. This thesis therefore studies a variety of novel III-V nanostructures, which have shown immense promise for inclusion in next-generation photonic devices, examining in detail these structures in terms of their optical properties and inherent carrier dynamics.