Engineering Commons^™

Investigating The Impact Of Unsupervised Feature-Extraction From Multi-Wavelength Image Data For Photometric Classification Of Stars, Galaxies And Qsos, Annika Lindh

Conference papers

Accurate classification of astronomical objects currently relies on spectroscopic data. Acquiring this data is time-consuming and expensive compared to photometric data. Hence, improving the accuracy of photometric classification could lead to far better coverage and faster classification pipelines. This paper investigates the benefit of using unsupervised feature-extraction from multi-wavelength image data for photometric classification of stars, galaxies and QSOs. An unsupervised Deep Belief Network is used, giving the model a higher level of interpretability thanks to its generative nature and layer-wise training. A Random Forest classifier is used to measure the contribution of the novel features compared to a set …

Investigating The Impact Of Unsupervised Feature-Extraction From Multi-Wavelength Image Data For Photometric Classification Of Stars, Galaxies And Qsos, Annika Lindh

Dissertations

This thesis reviews the current state of photometric classification in Astronomy and identifies two main gaps: a dependence on handcrafted rules, and a lack of interpretability in the more successful classifiers. To address this, Deep Learning and Computer Vision were used to create a more interpretable model, using unsupervised training to reduce human bias.

The main contribution is the investigation into the impact of using unsupervised feature-extraction from multi-wavelength image data for the classification task. The feature-extraction is achieved by implementing an unsupervised Deep Belief Network to extract lower-dimensionality features from the multi-wavelength image data captured by the Sloan Digital …

Short Term Forecasting Of Nitrogen Dioxide (No2) Levels Using A Hybrid Statistical And Air Mass History Modelling Approach, Aoife Donnelly, Owen Naughton, Brian Broderick, Bruce Misstear

Articles

A novel hybrid model has been developed to support the provision of real-time air quality forecasts. Statistical techniques have been applied in parallel with airmass history modelling to provide an efficient and accurate forecasting system with the ability to identify high NO2 events, which tend to be the episodes ofmost significance in Ireland. Airmass history modelling and k-means clustering are used to identify air mass types that lead to high NO2 levels in Ireland. Trajectory matching techniques allow data associated with these air masses to be partitioned during model development. Non-parametric regression (NPR) has been applied to describe nonlinear variations …

New Approach Of Modifying The Anatase To Rutile Transition Temperature In Tio2 Photocatalysts, Ciara Byrne, Rachel Fagan, Steven Hinder, Declan Mccormack, Suresh Pillai

Articles

In pure synthetic titanium dioxide, the anatase to rutile phase transition usually occurs between the temperatures of 600 °C and 700 °C. The phase transition temperature can be altered by various methods, including modifying the precursor or by adding dopant or modifier to the TiO2 sample. In an attempt to investigate the phase transition using aromatic carboxylic acids, the current study examines the impact of increasing concentrations of benzoic acid (1 : 0, 1 : 1, 1 : 4 and 1 : 8 molar ratio TiO2 : benzoic acid) on anatase to rutile transition. The samples were characterised using Raman …

First Outdoor Characterisation Of A Pv Powered Suspended Particle Device Switchable Glazing, Aritra Ghosh, Brian Norton, Aidan Duffy

Articles

Suspended particle device (SPD) switchable glazing is a candidate intervention to adaptively control solar heat gain. A high voltage low alternating current (AC) to operate a large area SPD applications, can be provided by a photovoltaic (PV) array. The first outdoor characterisation of side-by-side comparison of PV-powered SPD glazing has been conducted. Using an inverter to convert direct current (DC) power from PV to AC a 40 Wp PV device continuously powered a 0.07 W SPD glazing. High inverter power losses were found due to high PV inverter sizing ratio, inverter high self-consumption, and low solar radiation. Low sizing ratio …

Enhanced Corrosion Protection And Biocompatibility Of A Plga-Silane Coating On Az31 Mg Alloy For Orthopaedic Applications, Sankalp Agarwal, Muhammad Morshed, Marie-Noelle Labour, David Hoey, Brendan Duffy, James Curtin, Swarna Jaiswal

Articles

This paper reports a multi-step procedure to fabricate a novel corrosion resistant and biocompatible PLGA-silane coating on the magnesium (Mg) alloy AZ31. The first step involves alkaline passivation followed by dip coating in a methyltriethoxysilane (MTES) and tetraethoxysilane (TEOS) mixture to produce a cross-linked siloxane coating. The second step is to impart an amine functionalization to the silane modified surface by using 3-aminopropyl-triethoxy silane (APTES) for promoting adhesion of the acid terminated poly-(lactic-co-glycolic) acid (PLGA) as a final coating step. Static contact angle measurements, Fourier transform infrared spectroscopy and scanning electron microscopy analysis confirmed the successful assembly of coatings on …

Resolving The Policy Paradox: The Case Of Biofuel Production In Ireland, Alan Gilmer, Mark J. Mcgarrity, Vivienne Byers

Articles

Purpose – The purpose of this paper is to determine the status of policy design and policy implementation in the biofuel sector in Ireland. The focus of the work addresses the overarching operational context of the biofuel sector in Ireland and the role of different actors in shaping and resolving inconsistencies in policy outlook and practice. Design/methodology/approach – This study used a qualitative research approach involving a series of semi-structured interviews with members of the relevant sub-groups concerned. This study sought to address two questions – whether current or proposed policy is likely to affect consumption of indigenous biofuel feedstocks …

Predicting Intake Of Applications For First Registration In The Property Registration Authority, Orlaith Mernagh

Dissertations

The motivation for this dissertation is rooted in a real business need. The Property Registration Authority is the state organisation tasked with maintaining a register of land ownership on the island of Ireland. The PRA currently faces a series of challenges; a high level of staff retiring and the inherent loss of knowledge associated with this trend, a lack of recruitment in recent years and a large increase in lodgement of applications for first registration as a result of legislation. The organisation therefore requires a reliable system for predicting future intake. Prior to this project, there has also been a …

Unique Characterization Of Materials With Memory, John Murrough Golden

Articles

In general, materials with linear memory constitutive relations are characterized by a relaxation function. This leads to a situation where the free energy for most materials with memory is not unique. There is a convex set of free energy functionals with a minimum and a maximum element. An alternative procedure is proposed which characterizes a material by the kernel of the rate of dissipation functional. Using some recent results, we find that a unique free energy and relaxation function may then be deduced. An example is given for discrete spectrum materials. Also, the new results are used to show that …

Compositional Changes For Reduction Of Polymerisation-Induced Shrinkage In Holo, Dervil Cody, Mohesh Moothanchery, Emilia Mihaylova, Vincent Toal, Svetlana Mintova, Izabela Naydenova

Doctoral

Polymerisation-induced shrinkage is one of the main reasons why many photopolymer materials are not used for certain applications including holographic optical elements and holographic data storage. Here, two compositional changes for the reduction of shrinkage in an acrylamide-based photopolymer are reported. A holographic interferometric technique was used to study changes in the dynamics of the shrinkage processes occurring in the modified photopolymer during holographic recording in real time. Firstly, the effect of the replacement of the acrylamide monomer in the photopolymer composition with a larger monomer molecule, diacetone acrylamide, on polymerisation-induced shrinkage has been studied. A reduction in relative shrinkage …

Maximizing The Spatial Representativeness Of No2 Monitoring Data Using A Combination Of Local Wind-Based Sectoral Division And Seasonal And Diurnal Correction Factors, Aoife Donnelly, Owen Naughton, Bruce Misstear, Brian Broderick

Articles

This article describes a new methodology for increasing the spatial representativeness of individual monitoring sites. Air pollution levels at a given point are influenced by emission sources in the immediate vicinity. Since emission sources are rarely uniformly distributed around a site, concentration levels will inevitably be most affected by the sources in the prevailing upwind direction. The methodology provides a means of capturing this effect and providing additional information regarding source/pollution relationships. The methodology allows for the division of the air quality data from a given monitoring site into a number of sectors or wedges based on wind direction and …

Case Studies Of Cavity And External Wall Insulation Retrofitted Under The Irish Home Energy Saving Scheme: Technical Analysis And Occupant Perspectives, Aimee Byrne, Gerard Byrne, Garrett O'Donnell, Anthony Robinson

Articles

The residential sector represents 27% of primary energy consumption in Ireland. This paper examines the case study of the Irish government’s national grant scheme to encourage energy efficiency retrofit in private housing. That is the Home Energy Saving (HES) Scheme, later rebranded the Better Energy: Homes (BEH) Scheme. The methodology involved monitoring several homes immediately before and after retrofit alongside discussions with occupants. The examination focused on specific measures commonly introduced through the HES/BEH programme − cavity and external wall insulation. It has been found that a significant decrease in heat loss through the walls was measured in all cases. …