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Articles 1 - 21 of 21
Full-Text Articles in Physical Sciences and Mathematics
Ion Contribution To The Astrophysical Important 447.15, 587.56 And 667.82 Nm He I Spectral Lines Broadening, Vladimir Milosavljevic, Stevan Djenize
Ion Contribution To The Astrophysical Important 447.15, 587.56 And 667.82 Nm He I Spectral Lines Broadening, Vladimir Milosavljevic, Stevan Djenize
Articles
Characteristics of the astrophysical important Stark broadened 447.15 nm, 587.56 nm and 667.82 nm spectral line profiles have been measured at electron densities between 0.3 10 and 8.2 10 m and electron temperatures between 8000 and 33 000 K in plasmas created in five various discharge conditions using a linear, low-pressure, pulsed arc as an optically thin plasma source operated in a helium-nitrogen-oxygen gas mixture. On the basis of the observed asymmetry of the line profiles we have obtained their ion broadening parameters ( A) caused by influence of the ion microfield on the line broadening mechanism and also …
Digital Image Similarity For Geo-Spatial Knowledge Management, James Carswell
Digital Image Similarity For Geo-Spatial Knowledge Management, James Carswell
Conference papers
The amount and availability of high-quality geo-spatial image data, such as digital satellite and aerial photographs, is increasing dramatically. Task-based management of such visual information and associated knowledge is a central concern for organisations that rely on digital imagery. We are developing geo-spatial knowledge management techniques that employ case-based reasoning as the core methodology. In order to provide effective retrieval of task-based experiences that center around geo-spatial imagery, we need to forward novel similarity metrics for directly comparing the image components of experience cases. Based on work in geo-spatial image database retrieval, we are building an effective similarity metric for …
An Environment For Mobile Context-Based Hypermedia Retrieval, James Carswell
An Environment For Mobile Context-Based Hypermedia Retrieval, James Carswell
Conference papers
This paper proposes a novel solution to querying hyperlinked multimedia cultural heritage datasets based on the user's context. Context in this sense is defined as the user's location in virtual space and the particular mobile device being modeled together with user preferences or profile. The purpose is to automatically push relevant data from the database server to the client based on this comprehensive definition of the user's context. Consideration in regard to which mobile device is currently being modeled is a primary filter for determining what data will be sent and in what format. For example, image data will not …
Diffusion Based Grating Formation In A Photopolymer Material, Justin R. Lawrence
Diffusion Based Grating Formation In A Photopolymer Material, Justin R. Lawrence
Masters
Photopolymers are promising materials for use in holography. They have many advantages such as ease of use and are capable of efficiencies of up to 100%. However, the main disadvantage to these materials is their inability to record high spatial frequency gratings when compared to other materials such as dichromated gelatine and silver halide emulsion. This poor spatial frequency response is not predicted by any of the current physical modes. In this study, it is proposed that this effect is due to polymer chains growing away from their initiation point and causing a ‘smearing’ of the profile to be recorded. …
Geospatial Data Handling For Web-Based And Mobile Applications, James Carswell
Geospatial Data Handling For Web-Based And Mobile Applications, James Carswell
Articles
One of the main bottlenecks for web-based GIS usability is in the transmission and handling of the vast amounts of geospatial data involved. The shear volume of raster, vector, attribute, and other data to be analysed, queried, transmitted and displayed over the WWW in real-time is prohibited by connection speeds. In this paper we introduce e-Spatial technology, a fully integrated open standard web-based solution to manage multiple spatial relationships directly in an Oracle Spatial database and to deploy in real-time spatially enabled (or standard) applications completely independent of data volume. Indeed, no application code is ever installed on the client …
Web-Based Spatial Information Management Systems, James Carswell
Web-Based Spatial Information Management Systems, James Carswell
Conference papers
In this paper we discuss the innovative software solutions offered by e-SpatialTM technology for the deployment of web-based and mobile spatial information management systems. This technology has been developed within the Oracle 9i Database environment and allows users to build and deploy spatially enabled Internet applications on any Oracle supported hardware platform and on any device running a Java Virtual Machine (e.g., standard web browsers, PDAs and other mobile devices). The paper focuses on a Land Information Management System (LIMS) application developed for the Irish Department of Agriculture. The application utilises the e-SpatialTM Information Server to deliver a spatially enabled …
Development Of A Real-Time Digital Acquisition Software System For The Ocean Optics S1000 Spectrometer, Stephen Fennell
Development Of A Real-Time Digital Acquisition Software System For The Ocean Optics S1000 Spectrometer, Stephen Fennell
Masters
The objective of the M. Phil degree project was to improve the digital acquisition speed of the existing Ocean Optic I/O S1000 spectrometer system. Research carried out prior to this research work indicated that the existing system, although allowing for successful spectroscopic measurements, did not provide for a true time-base required for time-resolved spectroscopy. The analogue/digital speed aspects of the I/O were investigated and shortcomings were found in the digital I/O of the system. These shortcomings were investigated and the existing Ocean Optics software was found to have a considerable role in the lack of overall acquisition speed. Various Ocean …
Atmospheric Chemistry Of Aromatic Compounds, Bernadette Duffy
Atmospheric Chemistry Of Aromatic Compounds, Bernadette Duffy
Masters
Rate constants (in units of 10-11 cm3 molecule-1s-1) were measured for the following reactions at 298+-2K and 1 atmosphere pressure using a relative rate technique. k(OH+Benzene)= 1.42+-0.1; k(OH+p-Xylene)= 15.9 +-2.5 k(OH+Toluene)=6.30+-0.15; k(OH+o-Ethyltoluene)=14.1+-1.1; k(OH+Ethylbenzene)=7.50+-0.72:k(OH+m-Ethyltoluene)=23.0+-1.5; k(OH+o-Xylene)=14.5+-3.1; k(OH+p-Ethyltoluene)=14.2+-1.0; k(OH+m-Xylene=23.1+-2.2: k(OH+1,3,5-Rimethylbenzene= 69.7+-4.3 The increase in reactivity with increasing degree of alkyl substitution on the aromatic ring supports the conclusions of previous studies that the dominant reaction pathway at room temperature for reaction of hydroxyl radicals with aromatic compounds is addition to the benzene rig. The rate data are compared with previous measurements and discusses in terms of structure-activity relationships The Photochemical Ozone Creation Potentials …
Stark Shifts And Transition Probabilities In The Ne Ii Spectrum, Stevan Djenize, Vladimir Milosavljevic, Milan S. Dimitrijevic
Stark Shifts And Transition Probabilities In The Ne Ii Spectrum, Stevan Djenize, Vladimir Milosavljevic, Milan S. Dimitrijevic
Articles
Stark shifts (d) and transition probabilities of the spontaneous emission (Einstein's A values) of forty two singly charged neon ( ) ion spectral lines have been measured in a linear, low pressure, pulsed arc at 35 300 K electron temperature and 1.83 10 23 m -3 electron density. Transition probabilities have been obtained using the relative line intensity ratio (RLIR) method. Stark shift values have also been calculated, using the semiclassical perturbation formalism (SCPF). The measured and calculated shift values and the measured A values have been compared to the existing data taken from available data sources.
Clinical Assessment Of The Quantitative Posturography System (Qps), Jacinta Browne, G. O'Hare, A. Finn, J. Colin
Clinical Assessment Of The Quantitative Posturography System (Qps), Jacinta Browne, G. O'Hare, A. Finn, J. Colin
Articles
The objectives of this study were to evaluate a novel design dynamic force platform the Quantitative Posturography System (QPS). The evaluation consisted of identifying the effects due to ageing and disease of the postural control system and also to examine the relationship between functional performance and postural sway. An AOVA design and Pearson-Product correlation design were used. Seventy healthy subjects, seven subjects with Parkinson’s disease and eight subjects with a history of falls took part in the study. It was found that the QPS was able to identify changes due to both the ageing process and disease on the postural …
Generalized Moonshine And Orbifold Constructions, Michael Tuite, Rossen Ivanov
Generalized Moonshine And Orbifold Constructions, Michael Tuite, Rossen Ivanov
Conference papers
A brief review is given of some of our recent work on Generalised Monstrous Moonshine using abelian orbifoldings of the Moonshine Module.
Scale And Orientation-Invariant Scene Similarity Metrics For Image Queries, James Carswell
Scale And Orientation-Invariant Scene Similarity Metrics For Image Queries, James Carswell
Articles
In this paper we extend our previous work on shape-based queries to support queries on configurations of image objects. Here we consider spatial reasoning, especially directional and metric object relationships. Existing models for spatial reasoning tend to rely on pre-identified cardinal directions and minimal scale variations, assumption that cannot be considered as given in our image applications, where orientations and scale may vary substantially, and are often unknown. Accordingly, we have developed the method of varying baselines to identify similarities in direction and distance relations. Our method allows us to evaluate directional similarities without a priori knowledge of cardinal directions, …
On Unit Sum Numbers Of Rational Groups, Brendan Goldsmith, Christopher Meehan, S. Wallutis
On Unit Sum Numbers Of Rational Groups, Brendan Goldsmith, Christopher Meehan, S. Wallutis
Articles
The unit sum numbers of rational groups are investigated: the importance of the prime 2 being an automorphism of the rational group is discussed and other results are achieved by considering the number and distribution of rational primes which are, or are not, automorphisms of the group. Proof is given of the existence of rational groups with unit sum numbers greater than 2 but of finite value .
Bouncing Branes, Emil Prodanov
Bouncing Branes, Emil Prodanov
Articles
Two classical scalar fields are minimally coupled to gravity in the Kachru-Shulz-Silverstein scenario with a rolling fifth radius. A Tolman wormhole solution is found for a R x S^3 brane with Lorentz metric and for a R x AdS_3 brane with positive definite metric.
Some Irrational Generalised Moonshine From Orbifolds, Rossen Ivanov, Michael Tuite
Some Irrational Generalised Moonshine From Orbifolds, Rossen Ivanov, Michael Tuite
Articles
We verify the Generalised Moonshine conjectures for some irrational modular functions for theMonster centralisers related to the Harada-Norton, Held, M12 and L3(3) simple groups based on certain orbifolding constraints. We find explicitly the fixing groups of the hauptmoduls arising in each case.
K(Π, 1) For Artin Groups Of Finite Type, Colum Watt, Thomas Brady
K(Π, 1) For Artin Groups Of Finite Type, Colum Watt, Thomas Brady
Articles
This paper is a continuation of a programme to construct new K(π, 1)’s for Artin groups of finite type which began in [4] with Artin groups on 2 and 3 generators and was extended to braid groups in [3]. These K(π, 1)’s differ from those in [6] in that their universal covers are simplicial complexes. In [4] a complex is constructed whose top-dimensional cells correspond to minimal factorizations of a Coxeter element as a product of reflections in a finite Coxeter group. Asphericity is established in low dimensions using a metric of non-positive curvature. Since the nonpositive curvature condition is …
A Partial Order On The Orthogonal Group, Colum Watt, Thomas Brady
A Partial Order On The Orthogonal Group, Colum Watt, Thomas Brady
Articles
We define a natural partial order on the orthogonal group and completely describe the intervals in this partial order. The main technical ingredient is that an orthogonal transformation induces a unique orthogonal transformation on each subspace of the orthogonal complement of its fixed subspace.
Optical And Magnetic Behaviour Of Low Dimensional Structures, Francis Pedreschi
Optical And Magnetic Behaviour Of Low Dimensional Structures, Francis Pedreschi
Doctoral
Low dimensional structures can exhibit unusual properties due to the quantum confinement of electrons. This may manifest itself in any effects that depend on electron behaviour. In this study, the optical and magnetic properties in particular of two types of low dimensional structures are examines. Quantum wires are structures that have macroscopic length scales along one dimension and nanometre length scales in the others. Two Indium induced reconstructions of Silicon surfaces were grown and examined to determine if quantum confinement, a necessary requirement for a quantum wire, did exist for their structures. A UHV compatible Reflectance Anisotropy Spectroscopy (RAS) instrument, …
On Torsion And Mixed Minimal Abelian Groups, Brendan Goldsmith, S. O. Hogain
On Torsion And Mixed Minimal Abelian Groups, Brendan Goldsmith, S. O. Hogain
Articles
An abelian group is said to be minimal if it is isomorphic to all its subgroups of finite index. We obtain a complete characterisation of such groups in the torsion case; in the case of mixed groups of rank 1 we obtain a characterisation for some large classes of such groups.
Flow Patterns In A Two-Roll Mill, Christopher Hills
Flow Patterns In A Two-Roll Mill, Christopher Hills
Articles
The two-dimensional flow of a Newtonian fluid in a rectangular box that contains two disjoint, independently-rotating, circular boundaries is studied. The flow field for this two-roll mill is determined numerically using a finite-difference scheme over a Cartesian grid with variable horizontal and vertical spacing to accommodate satisfactorily the circular boundaries. To make the streamfunction numerically determinate we insist that the pressure field is everywhere single-valued. The physical character, streamline topology and transitions of the flow are discussed for a range of geometries, rotation rates and Reynolds numbers in the underlying seven-parameter space. An account of a preliminary experimental study of …
Rational Generalized Moonshine From Abelian Orbifoldings Of The Moonshine Module, Rossen Ivanov, Michael Tuite
Rational Generalized Moonshine From Abelian Orbifoldings Of The Moonshine Module, Rossen Ivanov, Michael Tuite
Articles
We consider orbifoldings of the Moonshine Module with respect to the abelian group generated by a pair of commuting Monster group elements with one of prime order p = 2, 3, 5, 7 and the other of order pk for k = 1 or k prime. We show that constraints arising from meromorphic orbifold conformal field theory allow us to demonstrate that each orbifold partition function with rational coefficients is either constant or is a hauptmodul for an explicitly found modular fixing group of genus zero. We thus confirm in the cases considered the Generalised Moonshine conjectures for all rational …