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Technological University Dublin

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2011

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Articles 1 - 30 of 101

Full-Text Articles in Physical Sciences and Mathematics

Drift Detection Using Uncertainty Distribution Divergence, Patrick Lindstrom, Brian Mac Namee, Sarah Jane Delany Dec 2011

Drift Detection Using Uncertainty Distribution Divergence, Patrick Lindstrom, Brian Mac Namee, Sarah Jane Delany

Conference papers

Concept drift is believed to be prevalent inmost data gathered from naturally occurring processes andthus warrants research by the machine learning community.There are a myriad of approaches to concept drift handlingwhich have been shown to handle concept drift with varyingdegrees of success.

However, most approaches make the keyassumption that the labelled data will be available at nolabelling cost shortly after classification, an assumption whichis often violated. The high labelling cost in many domainsprovides a strong motivation to reduce the number of labelledinstances required to handle concept drift. Explicit detectionapproaches that do not require labelled instances to detectconcept drift show great …


Nanozeolites Doped Photopolymer Layers With Reduced Shrinkage, Mohesh Moothanchery, Izabela Naydenova, Svetlana Mintova, Vincent Toal Dec 2011

Nanozeolites Doped Photopolymer Layers With Reduced Shrinkage, Mohesh Moothanchery, Izabela Naydenova, Svetlana Mintova, Vincent Toal

Articles

An acrylamide based photopolymer doped with pure silica MFI-type zeolite (silicalite-1) nanoparticles has been characterized for holographic recording purposes. The concentrations of the silicalite-1 nanoparticles in the photopolymer layers were 1, 2.5, 5 and 7.5 wt.%. The inclusion of silicalite-1 nanoparticle in the photopolymer has resulted in an increase of the diffraction efficiency by up to 40%, and decrease of the shrinkage from 1.32% to 0.57%. The best results were obtained in layers doped with 5 wt.% silicalite-1 nanoparticles.


Going Green, Dermot Kehily Dec 2011

Going Green, Dermot Kehily

Articles

No abstract provided.


Enhanced Quantum Dot Emission For Luminescent Solar Concentrators Using Plasmonic Interaction, Subhash Chandra, Manus Kennedy, John Doran, Sarah Mccormack, A. J. Chatten Nov 2011

Enhanced Quantum Dot Emission For Luminescent Solar Concentrators Using Plasmonic Interaction, Subhash Chandra, Manus Kennedy, John Doran, Sarah Mccormack, A. J. Chatten

Articles

Plasmonic excitation enhanced fluorescence of CdSe/ZnS core-shell quantum dots (QDs) in the presence of Au nanoparticles (NPs) has been studied for application in quantum dot solar concentrator (QDSC) devices. We observe that there is an optimal concentration of Au NPs that gives a maximum 53% fluorescence emission enhancement for the particular QD/Au NP composite studied. The optimal concentration depends on the coupling and spacing between neighboring QDs and Au NPs. We show the continuous transition from fluorescence enhancement to quenching, depending on Au NP concentration. The locally enhanced electromagnetic field induced by the surface plasmon resonance in the Au NPs …


Dc Pulsed Atmospheric Pressure Plasma Jet Image Information, Denis P. Dowling, F T. O'Neill, Vladimir Milosavljevic, Victor J. Law Nov 2011

Dc Pulsed Atmospheric Pressure Plasma Jet Image Information, Denis P. Dowling, F T. O'Neill, Vladimir Milosavljevic, Victor J. Law

Articles

This paper presents optical imaging and optical emission spectroscopy (OES) data of an atmospheric-pressure plasma jet. It is shown how the visual information and OES information of the air discharge are related as the blown arc extends from the nozzle (2-4 mm) with a molecular nitrogen rotational temperature on the order of 1700 K and the flowing afterglow beyond this region is dominated by the cooler (300-K) NO-O chemiluminescent reaction that produces NO2 species.


Understanding The Molecular Information Contained In Principal Component Analysis Of Vibrational Spectra Of Biological Systems, Franck Bonnier, Hugh Byrne Nov 2011

Understanding The Molecular Information Contained In Principal Component Analysis Of Vibrational Spectra Of Biological Systems, Franck Bonnier, Hugh Byrne

Articles

K-means clustering followed by Principal Component Analysis (PCA) is employed to analyse Raman spectroscopic maps of single biological cells. K-means clustering successfully identifies regions of cellular cytoplasm, nucleus and nucleoli, but the mean spectra do not differentiate their biochemical composition. The loadings of the principal components identified by PCA shed further light on the spectral basis for differentiation but they are complex and, as the number of spectra per cluster is imbalanced, particularly in the case of the nucleoli, the loadings under-represent the basis for differentiation of some cellular regions. Analysis of pure bio-molecules, both structurally and spectrally distinct, in …


The Role Of Colour Duplex Ultrasound In The Surveillance Of Patients Undergoing Endovascular Aneurysm Repair, Cleona Gray Nov 2011

The Role Of Colour Duplex Ultrasound In The Surveillance Of Patients Undergoing Endovascular Aneurysm Repair, Cleona Gray

Doctoral

No abstract provided.


Holographic Recording In Corona Charged Acrylamide-Based Mfi-Zeolite Photopolymer, Temenujka Yovcheva, Izabela Naydenova, Simeon Sainov, Vincent Toal, Svetlana Mintova Nov 2011

Holographic Recording In Corona Charged Acrylamide-Based Mfi-Zeolite Photopolymer, Temenujka Yovcheva, Izabela Naydenova, Simeon Sainov, Vincent Toal, Svetlana Mintova

Articles

The influence of corona charging on holographic recording in acrylamide-based photopolymer nanocomposite containing MFI zeolite nanoparticles has been studied. The holographic recording was carried out in two different geometries —transmission grating recording and total internal reflection grating recording. During the recording process, the layers were charged in a corona field. It was observed that independently of the corona polarity, in the case of transmission geometry of recording, the corona charging led to a decrease in the diffraction efficiency (DE) of the grating. In the case of the total internal reflection grating, the DE increased in the corona field presence.


Climate Change And The Conservation Of Archaeological Sites: A Review Of Impacts Theory, Caithleen Daly Nov 2011

Climate Change And The Conservation Of Archaeological Sites: A Review Of Impacts Theory, Caithleen Daly

Articles

This article identifies the current state of knowledge in the literature regarding the possible impacts of future climatic change on archaeological sites and ensembles. Drawing on the literature review a matrix of potential impacts is collated to provide a simplified overview. This theoretical ‘menu’ is then tested by applying it to a vulnerability assessment of the World Heritage site of Skellig Michael in Ireland. The case study results reveal some knowledge gaps, particularly in regard to the impacts of climate change on buried archaeological remains.


On The N-Wave Equations And Soliton Interactions In Two And Three Dimensions, Vladimir S. Gerdjikov, Rossen Ivanov, Assen V. Kyuldjiev Oct 2011

On The N-Wave Equations And Soliton Interactions In Two And Three Dimensions, Vladimir S. Gerdjikov, Rossen Ivanov, Assen V. Kyuldjiev

Articles

Several important examples of the N-wave equations are studied. These integrable equations can be linearized by formulation of the inverse scattering as a local Riemann–Hilbert problem (RHP). Several nontrivial reductions are presented. Such reductions can be applied to the generic N-wave equations but mainly the 3- and 4-wave interactions are presented as examples. Their one and two-soliton solutions are derived and their soliton interactions are analyzed. It is shown that additional reductions may lead to new types of soliton solutions. In particular the 4-wave equations with Z2xZ2 reduction group allow breather-like solitons. Finally it is demonstrated that …


Preparation And Characterization Of A Composite Of Gold Nanoparticles And Single-Walled Carbon Nanotubes And Its Potential For Heterogeneous Catalysis, Anne Shanahan, James Sullivan, Mary Mcnamara, Hugh Byrne Oct 2011

Preparation And Characterization Of A Composite Of Gold Nanoparticles And Single-Walled Carbon Nanotubes And Its Potential For Heterogeneous Catalysis, Anne Shanahan, James Sullivan, Mary Mcnamara, Hugh Byrne

Articles

A single-walled carbon nanotube-supported gold nanoparticle composite was prepared and characterized by X-ray diffraction, scanning transmission electron microscopy/scanning electron microscopy/transmission electron microscopy, energy-dispersive X-ray analysis, atomic absorption spectroscopy, nitrogen adsorption, Raman spectroscopy, and ultraviolet-visible spectroscopy. The Au particles were found to be crystalline, with a well-defined and narrow particle-size distribution, centered around 7 nm. The activity and selectivity of the composite for solventless aerobic oxidation of a secondary alcohol were examined, and a conversion efficiency of 95% was obtained.


Completeness Of Interacting Particles, Pavel Abramski Oct 2011

Completeness Of Interacting Particles, Pavel Abramski

Doctoral

This thesis concerns the completeness of scattering states of n _-interacting particles in one dimension. Only the repulsive case is treated, where thereare no bound states and the spectrum is entirely absolutely continuous, so the scattering Hilbert space is the whole of L2(Rn). The thesis consists of 4 chapters: The first chapter describes the model, the scattering states as given by the Bethe Ansatz, and the main completeness problem. The second chapter contains the proof of the completeness relation in the case of two particles: n = 2. This case had in fact already been treated by B. Smit (1997), …


Creating A Uniform Magnetic Field For The Equi-Biaxial Physical Testing Of Magnetorheological Elastomers; Electromagnet Design, Development And Testing., Dave Gorman, Stephen Jerrams, Ray Ekins, Niall Murphy Sep 2011

Creating A Uniform Magnetic Field For The Equi-Biaxial Physical Testing Of Magnetorheological Elastomers; Electromagnet Design, Development And Testing., Dave Gorman, Stephen Jerrams, Ray Ekins, Niall Murphy

Conference Papers

No abstract provided.


Euler Equations On A Semi-Direct Product Of The Diffeomorphisms Group By Itself, Joachim Escher, Rossen Ivanov, Boris Kolev Sep 2011

Euler Equations On A Semi-Direct Product Of The Diffeomorphisms Group By Itself, Joachim Escher, Rossen Ivanov, Boris Kolev

Articles

The geodesic equations of a class of right invariant metrics on the semi-direct product of two Diff(S) groups are studied. The equations are explicitly described, they have the form of a system of coupled equations of Camassa-Holm type and possess singular (peakon) solutions. Their integrability is further investigated, however no compatible bi-Hamiltonian structures on the corresponding dual Lie algebra are found.


Solutions To Quasi-Relativistic Multi-Configurative Hartree-Fock Equations In Quantum Chemistry, Carlos Argáez García, Michael Melgaard Sep 2011

Solutions To Quasi-Relativistic Multi-Configurative Hartree-Fock Equations In Quantum Chemistry, Carlos Argáez García, Michael Melgaard

Articles

We establish existence of infinitely many distinct solutions to the multi-configurative Hartree-Fock type equations for N-electron Coulomb systems with quasi-relativistic kinetic energy for the n th electron. Finitely many of the solutions are interpreted as excited states of the molecule. Moreover, we prove existence of a ground state. The results are valid under the hypotheses that the total charge Z of K nuclei is greater than N-1 and that Z is smaller than a critical charge. The proofs are based on a new application of the Lions-Fang-Ghoussoub critical point approach to nonminimal solutions on a complete analytic Hilbert-Riemann manifold.


Fluorescence Emission Study Of Cdse/Zns Quantum Dot And Au Nanoparticles Composite For Application In Quantum Dot Solar Concentrators, Subhash Chandra, John Doran, Manus Kennedy, S Mccormack, A Chatten Sep 2011

Fluorescence Emission Study Of Cdse/Zns Quantum Dot And Au Nanoparticles Composite For Application In Quantum Dot Solar Concentrators, Subhash Chandra, John Doran, Manus Kennedy, S Mccormack, A Chatten

Conference Papers

Fluorescence of core shell (CdSe/ZnS) quantum dots (QDs) and Au nanoparticles (NPs) composite has been studied for application in quantum dot solar concentrators (QDSC). We conclude two points from the particular QD/Au NP composite studied. One; for the particular Au NPs concentration, the relative fluorescence emission enhancement increases with decreasing QD concentration. Second; the enhancement is more pronounced for the Au nanoparticles whose surface plasmon resonance wavelength overlaps with the absorption peak of QDs. The fundamental concept that could describe the change in fluorescence emission of QDs in the presence of Au NPs is the locally enhanced electromagnetic field induced …


The Potential For Indicators In The Management Of Climate Change Impacts On Cultural Heritage, Caithleen Daly Sep 2011

The Potential For Indicators In The Management Of Climate Change Impacts On Cultural Heritage, Caithleen Daly

Conference papers

The global scale and unpredictable nature of climate change impacts on cultural heritage poses a challenge for conservation management. This article explores the potential of indicators as an aid for decision makers in the heritage sector. The author proposes a new indicator tool for addressing long-term stone recession impacts that may be related to climate change. The indicator is being installed at two World Heritage sites in Ireland but no results are available. The prototype was developed during doctoral research at the Technological University of Dublin.


Particle Transport And Stochastic Acceleration In The Giant Lobes Of Centaurus A, Stephen O'Sullivan Sep 2011

Particle Transport And Stochastic Acceleration In The Giant Lobes Of Centaurus A, Stephen O'Sullivan

Conference papers

The conditions within the giant lobes of Centaurus A are reviewed in light of recent radio and γ‐ray observations. Data from WMAP and ground‐based telescopes in conjunction with measurements from Fermi‐LAT constrain the characteristic field strength and the maximum electron energy. The implications for the transport of energetic particles are discussed in terms of residence times and cooling times within the lobes. Acceleration of electrons and UHECR via the second order Fermi mechanism is discussed.


Human Heuristics: Understanding The Impacts For Pharmaceutical Quality Risk Management, Nuala Calnan (Editor) Sep 2011

Human Heuristics: Understanding The Impacts For Pharmaceutical Quality Risk Management, Nuala Calnan (Editor)

Conference Papers

This paper addresses the influence of human heuristics (Biases) on the assessment of risk. A core principle underpinning effective Risk Management is the principle that Risk Management explicitly addresses uncertainty i.e., that it explicitly takes account of uncertainty, the nature of that uncertainty, and how it can be addressed. Heuristics are cognitive behaviours which come into play when we make judgements in the presence of uncertainty. How these behaviours are manifested is still the subject of much research, but there is evidence in the literature that heuristics are a source of significant bias and errors in judgement. Awareness of the …


Observations Of The Wind Resource Across The Dublin Urban Area, Keith Sunderland, Michael Conlon, Gerald Mills, Rowan Feely Sep 2011

Observations Of The Wind Resource Across The Dublin Urban Area, Keith Sunderland, Michael Conlon, Gerald Mills, Rowan Feely

Conference papers

This paper presents an investigation of wind observations made at three (of a network of ten) stations in Dublin. Two of the stations are located over different parts of the urbanized landscape and one is located at Dublin Airport, which exemplifies a typical meteorological station. The purpose of the analysis is to evaluate the nature of the wind resource in the urban area. The potential output of a range of commercially available micro wind turbines at one of the stations is considered. At this location, an anemometer is mounted in a similar manner to international examples of building mounted domestic …


A Framework For Generating Data To Simulate Application Scoring, Kenneth Kennedy, Sarah Jane Delany, Brian Mac Namee Aug 2011

A Framework For Generating Data To Simulate Application Scoring, Kenneth Kennedy, Sarah Jane Delany, Brian Mac Namee

Conference papers

In this paper we propose a framework to generate artificial data that can be used to simulate credit risk scenarios. Artificial data is useful in the credit scoring domain for two reasons. Firstly, the use of artificial data allows for the introduction and control of variability that can realistically be expected to occur, but has yet to materialise in practice. The ability to control parameters allows for a thorough exploration of the performance of classification models under different conditions. Secondly, due to non-disclosure agreements and commercial sensitivities, obtaining real credit scoring data is a problematic and time consuming task. By …


Prosodic Synchrony In Co-Operative Task-Based Dialogues: A Measure Of Agreement And Disagreement, Brian Vaughan Aug 2011

Prosodic Synchrony In Co-Operative Task-Based Dialogues: A Measure Of Agreement And Disagreement, Brian Vaughan

Conference papers

Prosodic synchrony has been reported to be an important aspect of conversational dyads. In this paper, synchrony in four different dyads is examined. A Time Aligned Moving Average (TAMA) procedure is used to temporally align the prosodic measurements for the detection of synchrony in the dyads. An overlapping windowed correlation procedure is used to measure synchrony for six different prosodic parameters: mean pitch, pitch range, mean intensity, intensity range, centre of gravity and spectral slope. This study shows that a windowed correlation procedure better captures the dynamic nature of speech synchrony than a single measure across a whole conversation. This …


Mathematical Methods For Biosensor Models, Qi Wang Aug 2011

Mathematical Methods For Biosensor Models, Qi Wang

Doctoral

A biosensor is defined as a compact analytical device incorporating a biological sensing element integrated within a physico-chemical transducer whose aim is to produce optical or electronic signals proportional to the concentration of an analyte in a sample. Biosensors offer enormous potential to detect a wide range of analytes in health care, the food industry, environmental monitoring, security and defence. The beneficial impact on society as a result of the availability of such systems is immense, therefore investigating any strategy that could reduce development times and costs and reveal alternative designs is of utmost importance. In particular, mathematical modelling and …


On The Acceleration Of Explicit Finite Difference Methods For Option Pricing, Stephen O'Sullivan, Conall O'Sullivan Aug 2011

On The Acceleration Of Explicit Finite Difference Methods For Option Pricing, Stephen O'Sullivan, Conall O'Sullivan

Articles

Implicit finite difference methods are conventionally preferred over their explicit counterparts for the numerical valuation of options. In large part the reason for this is a severe stability constraint known as the Courant–Friedrichs–Lewy (CFL) condition which limits the latter class’s efficiency. Implicit methods, however, are difficult to implement for all but the most simple of pricing models, whereas explicit techniques are easily adapted to complex problems. For the first time in a financial context, we present an acceleration technique, applicable to explicit finite difference schemes describing diffusive processes with symmetric evolution operators, called Super-Time-Stepping. We show that this method can …


Using Crowdsourcing In The Rating Of Emotional Speech Assets, Sarah Jane Delany, Alexey Tarasov, John Snel, Charlie Cullen Jul 2011

Using Crowdsourcing In The Rating Of Emotional Speech Assets, Sarah Jane Delany, Alexey Tarasov, John Snel, Charlie Cullen

Other resources

No abstract provided.


Smooth And Peaked Solitons Of The Camassa-Holm Equation And Applications, Darryl Holm, Rossen Ivanov Jul 2011

Smooth And Peaked Solitons Of The Camassa-Holm Equation And Applications, Darryl Holm, Rossen Ivanov

Articles

The relations between smooth and peaked soliton solutions are reviewed for the Camassa- Holm (CH) shallow water wave equation in one spatial dimension. The canonical Hamiltonian formulation of the CH equation in action-angle variables is expressed for solitons by using the scattering data for its associated isospectral eigenvalue problem, rephrased as a Riemann- Hilbert problem. The momentum map from the action-angle scattering variables T(TN) to the flow momentum (X) provides the Eulerian representation of the N-soliton solution of CH in terms of the scattering data and squared eigenfunctions of its isospectral eigenvalue problem. The …


The Preparation And Characterisation Of Silver Nanomaterials And Their Application In Sensing Techniques, Aoife Power Jul 2011

The Preparation And Characterisation Of Silver Nanomaterials And Their Application In Sensing Techniques, Aoife Power

Doctoral

In this work the impact of nanomaterial, specifically silver nanostructures, on sensing techniques is investigated. The work can be divided in to three sections, preparation and characterisation of silver nanoparticles, their application as a nanocomposite based chemiresistor humidity sensing device and finally their application within the surface enhanced (resonance) Raman spectroscopy, SE(R)RS, technique. In the first study silver nanoparticles were prepared as aqueous colloidal dispersions. The colloids were of either a defined diameter (average diameter ~ 20 nm) with high silver loading or lower loaded colloids of tuneable morphology and hence optical properties. In a subsequent study the high load …


A Novel Methodology For Evaluating User Interfaces In Health Care, Luca Longo, Bridget Kane Jun 2011

A Novel Methodology For Evaluating User Interfaces In Health Care, Luca Longo, Bridget Kane

Conference papers

A pilot study is reported to identify an improved method of evaluating digital user interfaces in health care. Experience and developments from the aviation industry and the NASA-TLX mental workload assessment tools are applied in conjunction with Nielsen heuristics for evaluating an Electronic Health Record System in an Irish hospital. The NASA-TLX performs subjective workload assessments on operators working with various human-computer systems. Results suggest that depending on the cognitive workload and the working context of users, the usability will differ for the same digital interface. We conclude that incorporating the NASA-TLX with Nielsen's heuristics offers a more reliable method …


How Can Software Smes Become Medical Device, Fergal Mccaffery, Valentine Casey, Martin Mchugh Jun 2011

How Can Software Smes Become Medical Device, Fergal Mccaffery, Valentine Casey, Martin Mchugh

Conference papers

The amount of software content within medical devices has grown considerably over recent years and will continue to do so as the level of complexity of medical devices increase. This is driven by the fact that software is introduced to produce sophisticated medical devices that would not be possible using only hardware. This therefore presents opportunities for software development SMEs to become medical device software development organisations. However, some obstacles need to be addressed and overcome in order to make the transition from being a generic software development organisation to becoming a medical device software development organisation. This paper describes …


Study Of The Shrinkage Caused By Holographic Grating Formation In Acrylamide Based Photopolymer Film, Mohesh Moothanchery, Izabela Naydenova, Vincent Toal Jun 2011

Study Of The Shrinkage Caused By Holographic Grating Formation In Acrylamide Based Photopolymer Film, Mohesh Moothanchery, Izabela Naydenova, Vincent Toal

Articles

We study the shrinkage in acrylamide based photopolymer by measuring the Bragg detuning of transmission diffraction gratings recorded at different slant angles and at different intensities for a range of spatial frequencies. Transmission diffraction gratings of spatial frequencies 500, 1000, 1500 and 2000 lines/mm were recorded in an acrylamide based photopolymer film having 60 ± 5 μm thickness. The grating thickness and the final slant angles were obtained from the angular Bragg selectivity curve and hence the shrinkage caused by holographic recording was calculated. The shrinkage of the material was evaluated for three different recording intensities 1, 5 and 10 …