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Articles 1 - 27 of 27
Full-Text Articles in Engineering
A New High Power Parallel Converter Scheme For Active Power Filters, Malabika Basu, S. P. Das, Gopal Dubey
A New High Power Parallel Converter Scheme For Active Power Filters, Malabika Basu, S. P. Das, Gopal Dubey
Articles
A new topology for efficient utilisation of parallel converters as VAR compensators and active power filters (APF) for high power loads is proposed. Because of limited power handling capacity of individual devices, paralleling is the choice to increase rating of equipment, while keeping the THD of the current at the PCC within the agency specified standards. It has been reported in the literature that paralleling several converters, rather than switches, is more reliable in sharing of load. From this perspective, multilevel converters carry lot of weight, as their typical power circuit configuration limits the stress on individual devices to an …
A System For Monitoring Pressures And Spinal Curvature In Spinally Injured People Immobilised On A Spinal Raft, Ruairí De Fréin, Eoin Flinn, Ted Burke
A System For Monitoring Pressures And Spinal Curvature In Spinally Injured People Immobilised On A Spinal Raft, Ruairí De Fréin, Eoin Flinn, Ted Burke
Articles
We present a system designed to study the pressure at various ‘hot spots’ on the back of the body and the deformation of the spine experienced by a patient when strapped to a spinal board, and the potential alleviation of both by the addition of an inflatable “spinal raft” (or other similar device). In measuring pressure we devised a system of air-filled sacks interfaced with a PC. Each sack, placed under a particular key point on the body, is inflated until its faces just begin to separate and a switch thereby opens. The pressure reading is then captured and displayed …
A Vocalisation-Based Drawing Interface For Disabled Children, Ted Burke
A Vocalisation-Based Drawing Interface For Disabled Children, Ted Burke
Articles
In our work with disabled children at Ireland’s National Rehabilitation Hospital, a problem we have experienced in the facilitation of art activities is that traditional art materials and standard computer drawing programs sometimes prove inaccessible. In this paper, an original system, called “PaintMyVoice” is presented which facilitates the creation of two or three-dimensional images using a variety of novel input modalities. In particular, vocalisations can be used to create original images of a variety of objects, including trees, flowers and landscape elements. Additional input to the system can optionally be provided via mouse, keyboard, switch interface or digital camera depending …
Investigation Of Novel Liquid Crystal Materials For Their Possible Applications, Minseok Chang
Investigation Of Novel Liquid Crystal Materials For Their Possible Applications, Minseok Chang
Masters
In this thesis I present four main topics. One is an introduction to liquid crystals and the second is an opto-electronic experimental setup. The third is an investigation of the dynamic properties of dendrimers, which show ferroelectric features. The last one is a research focused on understanding of the structures of two different types of De Vries smectic A liquid crystal phases. All research activities are performed by the hand-made but automatically controlled opto-electronic experimental setup. First, an introduction to liquid crystals is presented in easy language. Mainly there are two kinds of liquid crystals, thermotropic and lyotropic, but I …
A Differentiated Services Architecture For Quality Of Service Provisioning In Wireless Local Area Networks, Tristan Raimondi
A Differentiated Services Architecture For Quality Of Service Provisioning In Wireless Local Area Networks, Tristan Raimondi
Masters
Currently the issue of Quality of Service (QoS) is a major problem in IP networks due to the growth in multimedia traffic (e.g. voice and video applications) and therefore many mechanisms like IntServ, DiffServ, etc. have been proposed. Since the IEEE 802.11b (or Wi-Fi) standard was approved in 1999, it has gained in popularity to become the leading Wireless Local Area Network (WLAN) technology with millions of such networks deployed worldwide. Wireless networks have a limited capacity (11 Mbits/s in the case of Wi-Fi networks) owing to the limited amount of frequency spectrum available. At any given time there may …
Mechancial Characterization Of Unplasticised Polyvinylchloride Thick Pipes Using Electronic Speckle Pattern Interferometry, Emilia Mihaylova, Benjamin Potelon, Guntaka Tulasi Sridhar Reddy, Vincent Toal, Ciaran Smith
Mechancial Characterization Of Unplasticised Polyvinylchloride Thick Pipes Using Electronic Speckle Pattern Interferometry, Emilia Mihaylova, Benjamin Potelon, Guntaka Tulasi Sridhar Reddy, Vincent Toal, Ciaran Smith
Articles
In this work a number of techniques (electronic speckle pattern interferometry, holographic interferometry, strain gauge and finite element method) are brought to bear in order to establish consistency in the results of strain measurement. This is necessary if optical nondestructive testing methods, such as those used here, are to gain acceptance for routine industrial use. The FE model provides a useful check. Furthermore, ESPI fringe data facilitates the extension of FE models, an approach that is of growing importance in component testing. The use of in-plane and out-of-plane sensitive electronic speckle pattern interferometry (ESPI) for non-destructive material characterization of thick …
Power Coupling Between Two Step-Index Multimode Fibers Of Different Numerical Apertures With An Angular Misalignment, Cheng Gao, Gerald Farrell
Power Coupling Between Two Step-Index Multimode Fibers Of Different Numerical Apertures With An Angular Misalignment, Cheng Gao, Gerald Farrell
Articles
Coupling efficiency between two step- index multimode fibers of different numerical aper- tures with an angular misalignment is calculated. The theory is presented using radiometry and geometrical optics. The limit case of the calculation is consistent with a previously published result. The results may be useful for applications such as power launching between two types of fibers with different numerical apertures for example silica fiber and plastic optical fiber(POF) and with an angular misalignment.
Liquid Crystal Based Optical Switches, Yuliya Semenova, S. Dovgalets, Yuri Panarin, Gerald Farrell
Liquid Crystal Based Optical Switches, Yuliya Semenova, S. Dovgalets, Yuri Panarin, Gerald Farrell
Articles
Optical switches using two electro-optical effects in liquid crystals are proposed and investigated for incorporation in a switch matrix for optical networks. These two devices employ selective reflection in cholesteric layers and total reflection at the border between glass and nematic liquid crystal. Prototypes of these switches have been designed and their parameters have been investigated. Initial results suggest the switching contrast ratio of 38.5 and 42 dB, respectively, with insertion loss about 2.3…2.9 dB for polarized light.
A Wireless Traffic Probe For Radio Resource Management And Qos Provisioning In Ieee 802.11 Wlans, Mark Davis
A Wireless Traffic Probe For Radio Resource Management And Qos Provisioning In Ieee 802.11 Wlans, Mark Davis
Conference papers
The emergence of real-time services such as voice over IP (VoIP) and video streaming imposes stringent requirements on the performance of a network if quality of service (QoS) targets are to be achieved. In the case of wireless networks, some form of radio resource management (RRM) is typically required to allocate the available resources among the contending stations in accordance with their needs and respective priorities. A critical aspect of any RRM scheme is the ability to monitor resource usage and to determine the resource requirements on a per-station basis. In this paper we describe a wireless traffic probe for …
Comparison Between Theoretical And Practical Phase Computation, Pauline Sourdille, Aidan O'Dwyer
Comparison Between Theoretical And Practical Phase Computation, Pauline Sourdille, Aidan O'Dwyer
Conference papers
Transfer functions which are a composite of delay terms cause problems for computer packages, such as MATLAB, in calculating the frequency response open loop transfer function, as the form of the open loop transfer function is irrational. So, the delay terms have to be approximated. There are several ways to evaluate a delay term. A calculator such as MATHEMATICA uses the exact representation of the delay called the Euler form. A computer package such as MATLAB uses a rational approximation for the delay. Using the MATLAB built-in function pade(n,tau), the open loop transfer function of a system with delay can …
Optimal Control Strategy Of Upqc For Minimum Operational Losses, Malabika Basu, Michael Farrell, Michael Conlon, Kevin Gaughan, Eugene Coyle
Optimal Control Strategy Of Upqc For Minimum Operational Losses, Malabika Basu, Michael Farrell, Michael Conlon, Kevin Gaughan, Eugene Coyle
Conference papers
The paper deals with a new control technique for a unified power quality conditioner (UPQC), which is the most comprehensive of FACTS devices. The problems of power quality continue to gain in significance because of the proliferation of sensitive and harmonic producing loads in electrical networks. Greater awareness among customers with regard to supply integrity and a desire by suppliers to be able to guarantee a certain degree of power quality to customers is being reflected in the development of innovative power quality solutions. The UPQC, which is a combination of shunt and series compensation, is designed to cater for …
State Feedback Integral Control By Velocity-Based Multiple Model Networks, Ruiyao Gao, Aidan O'Dwyer
State Feedback Integral Control By Velocity-Based Multiple Model Networks, Ruiyao Gao, Aidan O'Dwyer
Conference papers
Velocity-based (VB) multiple model networks have the advantage of allowing the capture of the dynamics of non-linear systems when compared to conventional multiple model networks, for they build a direct relationship between the non-linear system and the VB linearisation. To have the best use of modelled dynamic information for the controller design, this paper proposes a novel controller design approach, which associates an integral action with state feedback in local controller design. It overcomes the difficulty in the implementation of the velocity-based approach, which normally involves deducing the differential signal. It holds continuity with linear control theory in the analysis …
Tuning Rules For Pi And Pid Control Of Time Delayed Processes: Some Recent Developments, Aidan O'Dwyer
Tuning Rules For Pi And Pid Control Of Time Delayed Processes: Some Recent Developments, Aidan O'Dwyer
Conference papers
The ability of PI and PID controllers to compensate many practical processes has led to their wide acceptance in industrial applications. The requirement to choose two or three controller parameters is most easily done using tuning rules. Starting with a general discussion of industrial practice, the paper will discuss, in particular, recent work in tuning rule development for processes with time delay.
Enhancing Process Performance Through Automatic Control, Aidan O'Dwyer
Enhancing Process Performance Through Automatic Control, Aidan O'Dwyer
Conference papers
The proportional integral derivative (PID) controller is the most dominant form of automatic controller in industrial use today. With this technique, it is necessary to adjust the controller parameters according to the nature of the process. Thus, for effective control of a pasteurisation process, for example, specific values need to be chosen for the P, I and D parameters, which will be different for the values required to control, for example, a distillation column. This tailoring of controller to process is known as controller tuning.
Control Loop Performance Assessment: A Classification Of Methods, Niall O'Connor, Aidan O'Dwyer
Control Loop Performance Assessment: A Classification Of Methods, Niall O'Connor, Aidan O'Dwyer
Conference papers
This paper presents an overview of a number of controller performance assessment techniques. The techniques discussed are divided into five categories, namely, time domain assessment, frequency domain assessment, minimum variance control (MVC) as a benchmark, statistical analysis, and other more ‘problem specific’ assessment techniques. Recent work, by various authors, in each of the five categories is outlined.
System Identification Using The Delta Operator, Aidan O'Dwyer
System Identification Using The Delta Operator, Aidan O'Dwyer
Conference papers
The aim of this contribution is to communicate, to a wide audience in signal processing and telecommunications, work that has been carried out, primarily in control engineering, on the use of alternative discrete time operators to the z-domain operator. The advantages of the delta domain operator will be communicated using examples, primarily with the aid of plotted results, to give a creative and easily understood impact. Some original work carried out by the author on identification issues will also be communicated.
Determination Of The Phase Of A Transfer Function: Theory Versus Practice, Pauline Sourdille, Aidan O'Dwyer
Determination Of The Phase Of A Transfer Function: Theory Versus Practice, Pauline Sourdille, Aidan O'Dwyer
Conference papers
In control systems, a way to evaluate the stability of a system is to determine the magnitude and phase of the open loop system transfer function in the frequency domain. But due to the nature of the phase expression, practice and theory are not aligned. Some problems arise when the phase is determined, caused by the properties of the arctan function. This paper analyses these phase problems for a third order lag system and a third order lag with time delay system. It also presents modifications to obtain the analytically correct phase values from the computed values.
Implementation Of New Modified Smith Predictor Designs, Pauline Sourdille, Aidan O'Dwyer
Implementation Of New Modified Smith Predictor Designs, Pauline Sourdille, Aidan O'Dwyer
Conference papers
This paper outlines two modified Smith predictors developed previously by the authors and then presents the implementation results of these structures for the control of a pilot scale heating and ventilation system, the PT 326 process trainer from Feedback Instruments Ltd. These results are compared to the results obtained with a Smith predictor structure.
Using Information Technology To Enhance Control Engineering Education: Some Experiences, Aidan O'Dwyer
Using Information Technology To Enhance Control Engineering Education: Some Experiences, Aidan O'Dwyer
Conference papers
In the past decade, the use of computer based design and analysis tools, such as MATLAB/SIMULINK, has revolutionised practice in Control Engineering. Concepts that were previously only understandable after sustained mathematical analysis or experimental work may now be readily simulated on the computer. Over the past four years, the author has experimented with the use of MATLAB/SIMULINK, in the lecture and laboratory environment, with degree and taught masters students in control engineering at Dublin Institute of Technology (DIT). It has been found that the tool helps to increase student understanding of challenging topics, to act as motivation to further exploration …
Towards A Unified Spatial-Temporal Data Model And Query Language For Geographical Information Systems., Patrick Browne, Mike Jackson
Towards A Unified Spatial-Temporal Data Model And Query Language For Geographical Information Systems., Patrick Browne, Mike Jackson
Conference papers
This paper outlines the principle features of a Ph.D. programme of work. Section one describes the aims of the research. Section two looks at the nature of digital maps and their importance in the broader context of geographic information. Section three looks at the two major aspects of the research. Section four discusses the role of category theory in the research. Finally the conclusion is presented in section five.
Using Structured P2p Overlay Networks To Build Content Sensitive Communities, Paul Stacey, Damon Berry, Eugene Coyle
Using Structured P2p Overlay Networks To Build Content Sensitive Communities, Paul Stacey, Damon Berry, Eugene Coyle
Conference papers
This paper details a proposed peer-to-peer system, which allows a user to join communities of other like-minded users in order to exchange files. Utilising the routing capabilities of Pastry, the proposed system includes an indexing service, which facilitates the creation of virtual rendezvous points for users with similar interests (manifested by shared keywords). Users are described by the content they store. By using vector space modelling techniques users can be grouped together to form content sensitive communities. The system is built to serve as the basis for a distributed archive of research papers. The system is designed to improve the …
Application Of Wavelet Transform To Power Quality (Pq) Disturbance Analysis, Malabika Basu, Biswajit Basu
Application Of Wavelet Transform To Power Quality (Pq) Disturbance Analysis, Malabika Basu, Biswajit Basu
Conference papers
This paper presents a wavelet analysis based time-frequency technique to identify power system transients and disturbances. A mother wavelet basis function (Littlewood- Paley (L-P)) with dyadic non-overlapping frequency hands has been used. The advantage of the proposed approach is in identification of the occurrence and duration of the disturbances. A few power signals with power quality disturbances have been analysed to show the effectiveness of the proposed technique.
Harmonic Distortion Caused By Ev Battery Chargers In The Distribution Systems Network And Its Remedy, Malabika Basu, Kevin Gaughan, Eugene Coyle
Harmonic Distortion Caused By Ev Battery Chargers In The Distribution Systems Network And Its Remedy, Malabika Basu, Kevin Gaughan, Eugene Coyle
Conference papers
An effective way to minimise harmonic pollution in power systems is by careful design of the equipment connected to them. It is important for designers of equipment associated with emerging technologies to be aware of the potential impact of their designs on power system quality. One such upcoming technology is electric vehicle (EV) battery charging which may contribute to high harmonic distortion in the power system during the charging period. The literature notes total harmonic distortion of up to 50%. These findings are the impetus behind the present paper, where an EV battery charger has been designed, with an inherent …
Combining Capacitor/Inductor And Idling Asynchronous Motor In Design Of A System For Balance Of A Large Two-Phase Industrial Load Over Three Phases, Eugene Coyle, M Farrell, W. J. Campbell
Combining Capacitor/Inductor And Idling Asynchronous Motor In Design Of A System For Balance Of A Large Two-Phase Industrial Load Over Three Phases, Eugene Coyle, M Farrell, W. J. Campbell
Conference papers
This paper describes the design and implementation of a new solution to power quality problems associated with large unbalanced nonlinear loads at fine glass furnace production utilities. Such furnaces use two-phase electricity for reasons of enhanced temperature control and in order to maintain consistency of glass viscosity. A significant risk of power failure is introduced due to this requirement. The furnace load is also nonlinear in nature, due to temperature control by electronic power switching. This gives rise to risks associated with high harmonic distortion. A new method in design of filters to alleviate problems associated with this type of …
Printed Planar Monopole Antenna With Electromagnetically Coupled Elements, Jonathan Evans, Francisco Lerma, Max Ammann
Printed Planar Monopole Antenna With Electromagnetically Coupled Elements, Jonathan Evans, Francisco Lerma, Max Ammann
Conference papers
In this paper, the addition of an EM-coupled element to the printed planar monopole antenna is investigated. While remaining simple to construct, modifications to the EM-coupled element are shown to reduce the lower edge frequency of the 10 dB impedance bandwidth by up to ∼19% (280 MHz at 1.5 GHz). The radiation patterns for these antennas are characteristic of monopole antennas - i.e. omnidirectional in the azimuth plane with a at the zenith - and are consistent within +/- 2 dB across their useful impedance bandwidths. By optimizing the feed arrangements on these antennas a 10 dB impedance bandwidth ratio …
Onset Based Audio Segmentation For The Irish Tin Whistle, Mikel Gainza, Bob Lawlor, Eugene Coyle
Onset Based Audio Segmentation For The Irish Tin Whistle, Mikel Gainza, Bob Lawlor, Eugene Coyle
Conference papers
A technique for segmenting tin whistle audio signals according to the position of the note onsets is presented. This method focuses on the characteristics of the tin whistle within Irish traditional music, customising a time-frequency based representation for detecting the instant when a note starts and releases. Musical ornamentation, such as cuts and strikes, are very common in Irish traditional music and are played during the onset stage. Taking advantage of this musical feature, a novel technique for improving the onset time estimation is also presented.
On The Empirical Balanced Truncation For Nonlinear Systems, Marissa Condon, Rossen Ivanov
On The Empirical Balanced Truncation For Nonlinear Systems, Marissa Condon, Rossen Ivanov
Articles
Novel constructions of empirical controllability and observability gramians for nonlinear systems for subsequent use in a balanced truncation style of model reduction are proposed. The new gramians are based on a generalisation of the fundamental solution for a Linear Time-Varying system. Relationships between the given gramians for nonlinear systems and the standard gramians for both Linear Time-Invariant and Linear Time-Varying systems are established as well as relationships to prior constructions proposed for empirical gramians. Application of the new gramians is illustrated through a sample test-system.