Engineering Commons^™

Leveraging Depolarization To Increase The Link Reliability For Wireless Sensors Operating In Hyper-Rayleigh Environments, Jeff Frolik, Vit Sipal, David J. Edwards

Articles

Wireless communications within enclosed environments such as aircraft and vehicles have been shown to experience fading with statistics that are worse than Rayleigh. Motivated by low-cost, low-complexity systems (e.g., wireless sensors) that may be deployed in such environments, this work explores the benefits of polarization diversity using very large data sets collected over a small area and over the 5-6 GHz band. The results also demonstrate that antennas capable of capturing depolarized signal components can significantly mitigate the harshest of fading environments.

Footwear Antennas For Body Area Telemetry, Domenico Gaetano, Patrick Mcevoy, Max Ammann, Jacinta Browne, Louise Keating, Frances Horgan

Articles

Antennas designed to link footwear sensors within body centric networks are introduced with two small UWB antennas, one directional and another quasi-omnidirectional. The radiating characteristics are evaluated for three positions on a sample sports shoe using a detailed simulation model and measurements with a homogenous foot phantom. Antenna performance is assessed for resilience to close proximity loading by the footwear materials and the phantom foot.

Small Wind Turbines In Turbulent (Urban) Environments: A Consideration Of Normal And Weibull Distributions For Power Prediction, Keith Sunderland, Thomas Woolmington, Jonathan Blackledge, Michael Conlon

Articles

The urban terrain and the associated morphological complexities therein, present significant challenges for the deployment of small wind turbines. In particular, a considerable amount of uncertainty is attributable to the lack of understanding concerning how turbulence within urban environments affects turbine productivity. Current wind turbine power output measurements (particularly for small/micro wind turbines) are based on an average wind speed over an observation period; with limited accountability of the variability of wind speed within the observation time frame. This paper however, presents two models that can instead accurately consider such wind speed variation and how it affects the turbine, based …

Dual Band Lte Planar Inverted-F Antenna For M2m Applications, Abraham Loutridis, Matthias John, Max Ammann

Articles

A Planar Inverted-F Antenna for M2M applications is presented. The antenna is located on a rectangular ground plane and operates across both LTE frequency bands (690-960 MHz) and (1710-2690 MHz). The low cost antenna has omni-directional characteristics. The efficiency is better than 86% in both bands and the gain is more than 1.38 dBi across the whole frequency range. A parametric study of key geometrical parameters is reported.

Dual Circularly-Polarized Patch Antenna Using Even And Odd Feed-Line Modes, Adam Narbudowicz, Xiulong Bao, Max Ammann

Articles

This paper proposes a new patch antenna with dual circularly polarized capability at 2.575 GHz. The design exploits the even and odd modes in a coplanar waveguide transmission line and enables simultaneous right- and left-handed circular polarization, with two individual excitation ports. A patch antenna is fed by multimode transmission line and the advantages and disadvantages are discussed. A prototyped antenna realized up to 20 dB isolation between ports with S21 < -10dB bandwidth of 87 MHz. Realized gains for the two modes of operation are 5.77 and 7.23 dBic. The proposed structure is compact and easy to manufacture.

Maximising Value Of Electrical Networks For Wave Energy Converter Arrays, Fergus Sharkey, Elva Bannon, Michael Conlon, Kevin Gaughan

Articles

Currently there are the beginnings of a commercial wave energy industry and the ultimate ambition will be to deploy Wave Energy Converters (WECs) in arrays, or wave farms, in a similar fashion to offshore wind. These arrays will require electrical networks to collect and export the generated electrical power to shore and onto the electrical grid. For large scale wind farms the inter-array and export electrical networks can represent more than 20% of the project’s capital expenditure. Submarine power cables account for a large proportion of this cost. The same is expected to be the same for WEC arrays.

This …

Single-Mode Tunable Laser Emission In The Single-Exciton Regime From Colloidal Nanocrystals, Christos Grivas, Chunyong Li, Peristera Andreakou, Pengfei Wang, Ming Ding, Gilberto Brambilla, Liberato Manna, Pavlos Lagoudakis

Articles

Whispering-gallery-mode resonators have been extensively used in conjunction with different materials for the development of a variety of photonic devices. Among the latter, hybrid structures, consisting of dielectric microspheres and colloidal core/shell semiconductor nanocrystals as gain media, have attracted interest for the development of microlasers and studies of cavity quantum electrodynamic effects. Here we demonstrate single-exciton, single-mode, spectrally tuned lasing from ensembles of optical antenna-designed, colloidal core/shell CdSe/CdS quantum rods deposited on silica microspheres. We obtain singleexciton emission by capitalizing on the band structure of the specific core/shell architecture that strongly localizes holes in the core, and the two-dimensional quantum …

Resource-Induced Voltage Flicker For Wave Energy Converters – Assessment Tools, Fergus Sharkey, Joe Macenri, Elva Bannon, Michael Conlon, Kevin Gaughan

Articles

For wave energy converters, the input resource has a typical period of 5–20 s depending on the site location and dominant seastates. Wave energy converters generally produce mechanical power twice per wave cycle and therefore depending on the storage available, the electrical power output has half the period of the input resource. These regular power changes induce a voltage change at the point of connection (POC) which is proportional to the amplitude of the power change and at the same frequency. Therefore the coupling of the input resource to the output power of a wave energy converter will cause voltage …

Footwear-Centric Body Area Network With Directional Uwb Antenna, Domenico Gaetano, Vit Sipal, Patrick Mcevoy, Max Ammann, C Brannigan, Louise Keating, Frances Horgan

Articles

A footwear-centric body area network employing a directional antenna is compared with waist-centric systems using omnidirectional and directional antennas. The impact of body movements on path gain is analysed for two bands at 3.99 GHz and 7.99 GHz. The path gain and data rate results demonstrate that footwear-centric configurations are equivalent or better than waist-centric body area networks.

Adaptive Ofdm For Wireless Interconnect In Confined Enclosures, Vit Sipal, Javier Gelabert, Christopher J. Stevens, Ben Allen, David Edwards

Articles

This letter considers and recommends OFDM with adaptive subcarrier modulation as a suitable candidate for wireless UWB communication in computer chassis. A rigorous measurement campaign studies the guaranteed spectral efficiency. It concludes that enhancement of the existing WiMedia OFDM systems with a bandwidth of 528 MHz in order to support adaptive OFDM would enable data-rates above 1 Gbps over short ranges, i.e. the spectral efficiency would be doubled. Moreover, the guaranteed spectral efficiency is shown to increase with bandwidth, i.e. the guaranteed data-rate increases better than linearly with bandwidth.

Comparison Of Non-Coherent Linear Detection Algorithms Applied To A 2-D Numerical Breast Model, Giuseppe Ruvio, Raffaele Solimene, Antonio Cuccaro, Max Ammann

Articles

A comparative analysis of an imaging method based on a multifrequency Multiple Signal Classification (MUSIC) approach against two common linear detection algorithms based on noncoherent migration is made. The different techniques are tested using synthetic data generated through CST Microwave Studio and a phantom developed from MRI scans of a mostly fat breast. The multifrequency MUSIC approach shows an overall superior performance compared to the noncoherent techniques. This letter reports that this highly performing algorithm does not require any antenna calibration or phase response estimation and allows the use of efficient and complex antenna geometries without difficult algorithm redefinitions.

Detecting Point-Like Sources Of Unknown Frequency Spectra, Raffaele Solimene, Giuseppe Ruvio, Angela Dell’Aversano, Antonio Cuccaro, Max Ammann, Rocco Pierri

Articles

The problem of detecting point-like sources whose frequency spectrum is unknown is addressed. Limitations of single-frequency approaches are identified by analytical as well as numerical arguments. To overcome these limits, different multifrequency approaches which combine frequency data incoherently are compared. In particular, a novel multifrequency MUSIC-like algorithm based on interferometric concepts is proposed. Results show that the algorithm outperforms other methods under comparison.

Evaluation Of Time Series Techniques To Characterise Domestic Electricity Demand, Fintan Mcloughlin, Aidan Duffy, Michael Conlon

Articles

This paper discusses time series approaches, often used by Transmission System Operators (TSOs) to forecast system demand, and applies them at an individual dwelling level. In particular, two techniques, Fourier transforms and Gaussian processes were evaluated and used to characterise individual household electricity demand. The performance of the characterisation approaches were evaluated based on Pearson correlation coefficient, descriptive statistics and paired sample t-tests for electrical parameters: Total Electricity Consumption, Maximum Demand, Load Factor and Time of Use of maximum electricity demand. Finally, a number of time series tests were carried out to ensure certain properties remained between the original and …

The Fractional Schrodinger-Klein-Gordon Equation And Intermediate Relativism, Jonathan Blackledge, Bazar Babajanov

Articles

By considering a random walk model compounded in Einstein's evolution equation, we show that both the classical Schrodinger and Klein-Gordon equations can be viewed a s consequence of introducing a memory function.

The purpose of this is to derive a wave equaiton that, on a phenomenological basis at least, describes the transitional characteristics of wave functions for spin-less particles that may exist in the intermediate of "semi relativistic regime.

Dual-Band Omnidirectional Circularly Polarized Antenna, Adam Narbudowicz, Xiulong Bao, Max Ammann

Articles

A dual-band omnidirectional circularly polarized antenna is proposed. The antenna comprises back-to-back microstrip patches fed by a coplanar waveguide. A very low frequency ratio of 1.182 has been achieved, which can be easily tuned by adjusting four lumped capacitors incorporated into the antenna. An analysis of the omnidirectional circular polarization mechanism as well the dual band operation is provided and confirmed by numerical and experimental data. Key parameters to tune the resonant frequencies and the axial ratio have been identified. The prototype antenna provides omnidirectional circular polarization in one plane with cross polar isolation better than 12 dB for both …

Estimation Of Wave Energy From Wind Velocity, Jonathan Blackledge, Eugene Coyle, Derek Kearney, Ronan Mcguirk, Brian Norton

Articles

The aim of this paper is to report on a possible correlation between the Levy index for wind velocity and the mean Energy Density of sea surface waves in the same location. The result is based on data obtained from 6 buoys located around the coast of Ireland and maintained by the Marine Institute of Ireland and a further 144 buoys located at various locations off the coast of the United States of America and maintained by the National Data Buoy Centre. These buoys provide historical data on the wind velocity, wave height and wave period as well as other …

Three Dimensional Simulation Of The Radiation Field Patterns Generated By An Integrated Antenna, Jonathan Blackledge, Bazar Babajanov

Articles

Simulating the electromagnetic field patterns generated by integrated antennas uses in mobile phones, for example, is fundamental to understanding their transmission characteristics and thereby engineering designs that optimize the directional properties of electromagnetic propagation. Modern integrated antennas have complex three-dimensional geometry designed to optimize their performance in terms of their multi-band and multi -modal attributes. This geometry, coupled with their close proximity to other component of the device (such as the battery and Printed Circuit Board, for example) produce complex field patterns due to the scattering of the electric (and magnetic) field within a spatial domain that is the same …

Comparison Of Non-Coherent Linear Breast Cancer Detection Algorithms Applied To A 2-D Numerical Breast Model, Giuseppe Ruvio, Raffaele Solimene, Antonio Cuccaro, Max Ammann

Articles

A comparative analysis of an imaging method based on a multi-frequency Multiple Signal Classification (MUSIC) approach against two common linear detection algorithms based on non-coherent migration is made. The different techniques are tested using synthetic data generated through CST Microwave Studio and a phantom developed from MRI scans of a mostly fat breast. The multi-frequency MUSIC approach shows an overall superior performance compared to the non-coherent techniques. This paper reports that this highly performing algorithm does not require any antenna calibration or phase response estimation and allows the use of efficient and complex antenna geometries without difficult algorithm redefinitions.

The Influence Of Light Beam Convergence On The Stop-Bands Of A One-Dimensional Photonic Crystal, Vladimir A. Tolmachev, Kevin Berwick, Tatiana S. Perova

Articles

The influence of beam convergence on the photonic band-gaps, or stop-bands (SBs), of onedimensional photonic crystals (1D PCs) is investigated. The investigation is based on an analysis of the gap map obtained from reflection spectra, calculated by the transfer matrix method for various angles of light incidence, φ, The calculated data is compared with reflection spectra taken using Fourier Transform Infrared microspectroscopy. It was found that the introduction of the parameter, Δφ to account for the focused light beam, for angles up to 20°, has little effect on the first, or lowest SB and the SBs adjacent to it. However, …

Reversible Photoluminescence Quenchin Of Cdse/Zns Quantum Dots Embedded In Porous Glass By Ammonia Vapor, A. O. Orlova, Yu A. Gromova, V. G. Maslov, O. V. Andreeva, A. V. Baranov, A. V. Federov, A. V. Prudnikau, M. V. Artemyev, Kevin Berwick

Articles

The photoluminescence response of semiconductor CdSe/ZnS quantum dots embedded in a borosilicate porous glass matrix to exposure to ammonia vapor is investigated. Formation of surface complexes on the quantum dots results in quenching of the photoluminescence and a shortening of the luminescence decay time. The process is reversible, desorption of ammonia molecules from the quantum dot surface causes the photoluminescence to recover. The sensitivity of the quantum dot luminescence intensity and decay time to the interaction time and the reversibility of the photoluminescence changes makes the CdSe/ZnS quantum dot in porous glass system a candidate for use as an optical …

Wave Function Solutions By Transformation From The Helmholtz To Laplacian Operator, Jonathan Blackledge, Bazar Babajanov

Articles

The Helmholtz, Schr¨odinger and Klein-Gordon equations all have a similar form (for constant wavelength) and have applications in optics, quantum mechanics and relativistic quantum mechanics, respectively. Central to these applications is the theory of barrier and potential scattering,which, through application of the Green’s function method yields transcendental equations for the scattered wave function thereby requiring approximation methods to be employed. This paper reports on a new approach to solving this problem which is based on transforming the Helmholtz operator to the Laplacian operator and applying a Green’s function solution to the Poisson equation. This approach yields an exact forward and …

Financial Forecasting Using The Kolmogorov-Feller Equation, Jonathan Blackledge, Marc Lamphiere, Kieran Murphy, Shaun Overton

Articles

An approach to analysing a financial time series using the Kolmogorov-Feller Equation is considered, in particular, the Generalised Kolmogorov-Feller Equation (GKFE) subject to variations in the Stochastic Volatility. Using the Mittag-Leffler memory function, we derive an expression for the Impulse Response Function associated with a short time window of data which is then used to derive an algorithm for computing a new index using a standard moving window process. It is shown that application of this index to financial time series, subject to a low volatility condition, correlates with the start, direction and end of a trend depending on the …

On The Dirac Scattering Problem, Jonathan Blackledge, Bazar Babajanov

Articles

We consider a method of solving the Dirac scattering problem based on an approach previously used by the authors to solve the Schrodinger scattering problem to develop a conditional exact scattering solution and an unconditional series solution. We transform the Dirac scattering problem into a form that facilitates a soltuion based on the relativistic Lippmann-Schwinger equation using the relativistic Green's function that is transcendental in terms of the scattered field. Using the Dirac operator, this solution is transformed further to yield a modified relativistic Lippman-Schwinger equation that is also transcendental in terms of the scattered field. This modified solution faclitates …

Inverter Performance For Small Wind Turbines When Connected In Paralled With The Low-Voltage Distribution System, Jonathan Blackledge, Eugene Coyle, Derek Kearney, Eamonn Murphy

Articles

Small wind turbines have been installed in urban and turbulent locations with surprisingly poor performance and this has been backed up by data from a trial at the Technological University Dublin. In order to develop the small wind turbine industry a careful examination of assessment methods for the wind resource is required. Small wind turbines connected in parallel with the grid use inverters. As the wind turbine is not always at max output, a Weighted Average Efficiency for wind inverters is proposed. Pitfalls associated with developing an accurate weighted average efficiency for an inverter are identified and this will enable …

Selection Of Design Parameters To Reduce The Zero-Sequence Circulating Current Flow In Parallel Operation Of Dc Linked Multiple Shunt Apf Units, Shafiuzzaman Khadem, Malabika Basu, Michael Conlon

Articles

Capacity enhancement and operational flexibility are two of the important limitations of the centralized shunt APF unit. These limitations can be conquered by the operation of multiple APF units in parallel and connected back to back by a common DC link capacitor. In that case, a circulating current (CC) flows within the APF units. This CC flow becomes out of control when the APF units operate in hysteresis based current controlled mode. One of the difficulties of this CC flow control or reduction is the variable switching frequency of the APF units. In this paper the model for CC flow …

Correspondence: Comparing Led Luminaires, James Duff

Articles

A recent editorial within Lighting Research and Technology 1 suggests the need for ‘a simple set of questions to ask the LED supplier’. This article will present such a set of questions, but also, and perhaps more importantly, a set of responses that might be considered appropriate. The information used to form these questions and answers has been drawn from a number of useful resources 2-7, interaction with various lighting professionals and through the authors own experience. The purpose of these questions is to generate discussion. The author understands the questions posed can be improved upon and it is hoped …

Lumped Time-Delay Compensation Scheme For Coding Synchronization In The Nonlinear Spectral Quantization-Based All-Optical Analog-To-Digital Conversion, Zhe Khang, Jinhui Yuan, Qiang Wu, Tao Wang, Sha Li, Chongxiu Y, Gerald Farrell

Articles

this paper, we propose a novel lumped time-delay compensation scheme for the all-optical analog-to-digital conversion based on soliton self-frequency shift and optical interconnection techniques. By inserting a segment of negative dispersion fiber between the quantization and the coding module, the time delay of different quantized pulses can be accurately compensated with a simple structure compared to the multiple time-delay lines. The simulation results show that the coding pulses can be well synchronized using a span of fiber, with the flattened negative dispersion within the wavelength range of 1558-1620 nm. In addition, the problems of pulse broadening and time error are …

Proximity Heating Effects In Power Cables, Jonathan Blackledge, Eugene Coyle, Kevin O'Connell

Articles

Researchers at Technological University Dublin (DIT) have developed a new modelling system for evaluating the two and three dimensional heating effects in power cables due to harmonic distortion and proximity field effects.

Evaluation Of Proximity Heating Effects In Power Cables, Jonathan Blackledge, Eugene Coyle, Kevin O'Connell

Articles

No abstract provided.

A Review Of Existing Microgrid Architectures, Lubna Mariam, Malabika Basu, Michael Conlon

Articles

The future electricity network must be flexible, accessible, reliable, and economic according to the worldwide smartgrid initiative. This is also echoed by the Sustainable Energy Authority of Ireland (SEAI) and European Electricity Grid Initiative (EEGI). In order to facilitate these objectives and to reduce green house gas (GHG) emission, research on various configurations of microgrid system is gaining importance, particularly with high penetration of renewable energy sources. Depending on the resource availability, geographical locations, load demand, and existing electrical transmission and distribution system, uG can be either connected to 6the grid or can work in an autonomous mode. Storage can …