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Articles 4051 - 4080 of 4606

Full-Text Articles in Engineering

A Wireless Traffic Probe For Radio Resource Management And Qos Provisioning In Ieee 802.11 Wlans, Mark Davis Jan 2004

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 …

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Power Coupling Between Two Step-Index Multimode Fibers Of Different Numerical Apertures With An Angular Misalignment, Cheng Gao, Gerald Farrell Jan 2004

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.

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Purchasing Consortia And Electronic Markets: A Procurement Direction In Integrated Supply Chain Management, Bernd Huber, Edward Sweeney, Austin Smyth Jan 2004

Purchasing Consortia And Electronic Markets: A Procurement Direction In Integrated Supply Chain Management, Bernd Huber, Edward Sweeney, Austin Smyth

Articles

In supply chain management literature, there has been little empirical research investigation on purchasing consortium issues focusing on a detailed analysis of information and communication (ICT) based procurement strategies. Based on the exploration of academic literature and two surveys among purchasing organisations as well as e-Marketplaces / procurement service providers (PSPs) in the automotive and electronics industry sectors, the research methodology follows a positivistic approach in order to assess the overall statement: ‘Effective participation in electronic purchasing consortia (EPC) can have the potential to enhance competitive advantage. Implementation therefore requires a clear and detailed understanding of the major process structures …

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Information And Communication Technologies (Ict) Practices In Small Italian Transport And Logistics Service Providers: Empirical Findings And Critical Issues, Maurizio Caiazzo, Pietro Evangelista, Edward Sweeney Jan 2004

Information And Communication Technologies (Ict) Practices In Small Italian Transport And Logistics Service Providers: Empirical Findings And Critical Issues, Maurizio Caiazzo, Pietro Evangelista, Edward Sweeney

Conference papers

No abstract provided.

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Rationalising The Construction Materials Purchasing Process, Alan V. Hore Jan 2004

Rationalising The Construction Materials Purchasing Process, Alan V. Hore

Conference papers

This paper is concerned with the process used in locating and removing inefficiency in the construction materials purchasing process. In the first part, a case study is presented showing the build-up of costs involved in purchasing materials. Potential for substantial savings is revealed. The second part of the paper gives a status report on a rationalisation pilot project currently being undertaken by the Construction Information Technology Alliance (CITA). This project aims to show how greater effectiveness and efficiency can be applied to the administration of the construction materials purchasing process by the application of information technology already used widely in …

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Applications Of Simulation In Semiconductor Manufacturing Facilities, Amr Arisha, Paul Young Jan 2004

Applications Of Simulation In Semiconductor Manufacturing Facilities, Amr Arisha, Paul Young

Conference papers

Semiconductor fabrication facilities face many challenges through the many phases of their life cycle including design, build, various production ramps, and many levels of production. Confronted with global competition and rapidly changing technology and customer requirements, there is an increasing demand for rapid solution techniques to improve efficiency in manufacturing. The complexities and forces of both market and the process combine to make the use of simulation crucial at many different planning and control levels. While not a panacea for sustainable performance, simulation provides an effective vehicle for defining the path from competitive concepts to real world solutions and gives …

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Preparation Of (Pb,Ba)Tio3 Powders And Highly Oriented Thin Films By A Sol-Gel Process, Stacey Boland, Suresh Pillai, Wein-Duo Yang, Sossina Haile Jan 2004

Preparation Of (Pb,Ba)Tio3 Powders And Highly Oriented Thin Films By A Sol-Gel Process, Stacey Boland, Suresh Pillai, Wein-Duo Yang, Sossina Haile

Articles

Solid solution Pb1-xBaxTiO3, with particular emphasis on Pb0.5Ba0.5TiO3, was prepared
using a sol-gel process incorporating lead acetate trihydrate, barium acetate, and
titanium isopropoxide as precursors, acetylacetone (2,4 pentanedione) as a chelating
agent, and ethylene glycol as a solvent. The synthesis procedure was optimized by
systematically varying acetylacetone: Ti and H2O:Ti molar ratios and calcination
temperature. The resulting effects on sol and powder properties were studied using
thermogravimetric analysis/differential scanning calorimetry, Fourier transform infrared
spectroscopy, Brunauer-Emmett-Teller analysis, and x-ray diffraction (XRD).
Crystallization of the perovskite structure occurred at a temperature as low as 450 °C.
Thin films were prepared by spin …

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On The Empirical Balanced Truncation For Nonlinear Systems, Marissa Condon, Rossen Ivanov Jan 2004

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.

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The Investigation Of A Wireless Medical Homecare Data Logger, Aisling Cronin Jan 2004

The Investigation Of A Wireless Medical Homecare Data Logger, Aisling Cronin

Masters

Modern, portable self-measurement devices such as hand-held glucometers and ECG instruments can provide feedback in electronic form to patients. However the information is mostly transmitted by proprietary cable and there is no agreed format for migrating this data to information systems in clinics where it can be used by clinicians. The result is a muddle of transport mechanisms and software. There is a clear need for a simple, open and agreed means of data communication to help patients to manage their condition and to support clinicians who engage in home telemonitoring. To allow patients freedom to move, the first stage …

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Bs News Jan 2004

Bs News

Building Services Engineering

No abstract provided.

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Software Quality Revisited, Ronan Fitzpatrick Jan 2004

Software Quality Revisited, Ronan Fitzpatrick

Conference papers

Definitions of software quality have focused on software product quality factors. Quality that focuses on product quality is referred to by Kaoru Ishikawa as a narrow view of quality and he suggests that a broader more embracing and inclusive view is really necessary. The requirements of successful E-Commerce Web sites demonstrate this view. While the site might be considered as the product, Web site producers, owners and visitors also have a “quality” requirement. This broader view gives rises to the need to research and understand quality-of-development, quality-of-ownership, quality-of-engagement as well as quality-of-product. From the quality-of-product perspective, while many of the …

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Software Quality Challenges., Ronan Fitzpatrick, Peter Smith, Brendan O'Shea Jan 2004

Software Quality Challenges., Ronan Fitzpatrick, Peter Smith, Brendan O'Shea

Conference papers

This paper sets out a number of challenges facing the software quality community. These challenges relate to the broader view of quality and the consequences for software quality definitions. These definitions are related to eight perspectives of software quality in an end-to-end product life cycle. Research and study of software quality has traditionally focused on product quality for management information systems and this paper considers the challenge of defining additional quality factors for alternative domains like the World Wide Web.

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Towards A Unified Spatial-Temporal Data Model And Query Language For Geographical Information Systems., Patrick Browne, Mike Jackson Jan 2004

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.

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Studies In Cardiac Defribrillation, Eamonn Mckenna Jan 2004

Studies In Cardiac Defribrillation, Eamonn Mckenna

Masters

Cardiac disease resulting in cardiac arrest is one of the most common fatal diseases in the developed world. Defibrillation is the medical procedure used to correct the irregular cardiac rhythm (ventricular fibrillation (VF)) which is very often detected in patients suffering cardiac arrest. In the work reported in this thesis, two aspects of the defibrillation of patients in VF were examined. The first area of investigation concentrated on the use of multiple defibrillation electrodes to be used during closed chest (transthoracic) defibrillation. This study was carried out in a saline bath and centred on “focusing” electric fields from perimeter electrodes …

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Application Of Espi-Method For Strain Analysis In Thin Wall Cylinders, David Kennedy, Zdravko Schauperl, Seamus Greene, Emilia Mihaylova Jan 2004

Application Of Espi-Method For Strain Analysis In Thin Wall Cylinders, David Kennedy, Zdravko Schauperl, Seamus Greene, Emilia Mihaylova

Articles

The Centre for Industrial and Engineering Optics, DIT, Ireland, have recently developed and applied new optical techniques for the measurement of mechanical strain, one of which was based on electronic speckle pattern interferometry (ESPI). The accuracy of this optical technique when used on flat surfaces is well established. In this research the technique is tested on curved surfaces, and results are compared with the theoretical hoop strain as predicted by the bi-axial strain equation modified for the thin cylinder, and by those obtained by electrical resistance strain gauge (ERSG) undoubtedly the principal method of measuring mechanical strain. For testing procedures, …

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Mechancial Characterization Of Unplasticised Polyvinylchloride Thick Pipes Using Electronic Speckle Pattern Interferometry, Emilia Mihaylova, Benjamin Potelon, Guntaka Tulasi Sridhar Reddy, Vincent Toal, Ciaran Smith Jan 2004

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 …

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Control Loop Performance Assessment: A Classification Of Methods, Niall O'Connor, Aidan O'Dwyer Jan 2004

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.

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Tuning Rules For Pi And Pid Control Of Time Delayed Processes: Some Recent Developments, Aidan O'Dwyer Jan 2004

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.

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Comparison Between Theoretical And Practical Phase Computation, Pauline Sourdille, Aidan O'Dwyer Jan 2004

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 …

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System Identification Using The Delta Operator, Aidan O'Dwyer Jan 2004

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.

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Using Structured P2p Overlay Networks To Build Content Sensitive Communities, Paul Stacey, Damon Berry, Eugene Coyle Jan 2004

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 …

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Application Of Wavelet Transform To Power Quality (Pq) Disturbance Analysis, Malabika Basu, Biswajit Basu Jan 2004

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.

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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 Jan 2004

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 …

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Time-Frequency Analysis Applied To Autonomic Nervous System Activity In A Biofeedback Environment, James Condron Jan 2004

Time-Frequency Analysis Applied To Autonomic Nervous System Activity In A Biofeedback Environment, James Condron

Doctoral

The Autonomic Nervous System (ANS) is a subconscious system within the peripheral nervous system that controls such things as heart rate, respiration, baroreceptor control, sweating, and regulation of internal organs. Certain aspects of this system can be under conscious control given time and practices. The ANS may be further divided into two subsections, namely the Sympathetic (Fight or Flight) and Parasympathetic ( Rest and Digest) nervous system. These systems work symbiotically; however they have almost opposite effects on organs within the body. Within this project a compelling biofeedback game was built with a protocol whereby the users used their relaxation …

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Real-Time Sound Source Separation: Azimuth Discrimination And Resynthesis, Dan Barry, Robert Lawlor, Eugene Coyle Jan 2004

Real-Time Sound Source Separation: Azimuth Discrimination And Resynthesis, Dan Barry, Robert Lawlor, Eugene Coyle

Conference papers

We present a real-time sound source separation algorithm which performs the task of source separation based on the lateral displacement of a source within the stereo field. The algorithm exploits the use of the pan pot as a means to achieve image localisation within stereophonic recordings. As such, only an interaural intensity difference exists between left and right channels for a single source. Gain scaling and phase cancellation techniques are used in the frequency domain to expose frequency dependent nulls across the Azimuth plane. The position of these nulls in conjuction with magnitude estimation and grouping techniques are then used …

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An Efficient Phasiness Reduction Technique For Moderate Audio Time-Scale Modification, David Dorran, Eugene Coyle, Robert Lawlor Jan 2004

An Efficient Phasiness Reduction Technique For Moderate Audio Time-Scale Modification, David Dorran, Eugene Coyle, Robert Lawlor

Conference papers

Phase vocoder approaches to time-scale modification of audio introduce a reverberant/phasy artifact into the time-scaled output due to a loss in phase coherence between short-time Fourier transform (STFT) bins. Recent improvements to the phase vocoder have reduced the presence of this artifact, however, it remains a problem. A method of time-scaling is presented that results in a further reduction in phasiness, for moderate time-scale factors by taking advantage of some flexibility that exists in the choice of phase required so as to maintain horizontal phase coherence between related STFT bins. Furthermore, the approach leads to a reduction in computational load …

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Harmonic Sound Source Separation Using Fir Comb Filters, Mikel Gainza, Robert Lawlor, Eugene Coyle Jan 2004

Harmonic Sound Source Separation Using Fir Comb Filters, Mikel Gainza, Robert Lawlor, Eugene Coyle

Conference papers

A technique for separating harmonic sound sources using FIR comb filters is presented. First, a pre-processing task is performed by a multipitch estimator to detect the pitches that the signal is composed of. Then, a method based on the Short Time Fourier Transform (STFT) is utilized to iteratively extract the harmonics belonging to a given source by using FIR comb filters. The presented approach improves upon exising sinusoidal model approaches in terms of the perceptual quality of the extracted signal.

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Sound Source Separation: Azimuth Discrimination And Resynthesis, Dan Barry, Robert Lawlor Jan 2004

Sound Source Separation: Azimuth Discrimination And Resynthesis, Dan Barry, Robert Lawlor

Conference papers

This paper discusses a novel sound source separation algorithm which requires no prior knowledge, no learning, assisted or otherwise and performs the task of separation based purely on Azimuth discrimination within the stereo field. The algorithm exploits the use of the pan pot as a means to achieve image localisation within stereophonic recordings. As such, only an interaural intensity difference exists between left and right channels for a single source. The authors use gain scaling and phase cancellation techniques to expose frequency dependent nulls across the Azimuth domain from which source separation and resynthesis is carried out. Results are presented …

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Single Note Ornaments Transcription For The Irish Tin Whistle Based On Onset Detection, Mikel Gainza, Eugene Coyle, Robert Lawlor Jan 2004

Single Note Ornaments Transcription For The Irish Tin Whistle Based On Onset Detection, Mikel Gainza, Eugene Coyle, Robert Lawlor

Conference papers

Oranamentation plays a very important role in Irish traditional music giving more expression to the music by altering or embellishing small pieces of a melody. Single-note ornamentation, such as cuts and strikes, are the most common type in Irish traditional music and are played by articulating the note pitch during the onset stage. A technique for transcribing single note ornamentation for the tin whistle is based on onset detection 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 new notes played using single …

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Onset Detection And Music Transcription For The Irish Tin Whistle, Mikel Gainza, Robert Lawlor, Eugene Coyle, Aileen Kelleher Jan 2004

Onset Detection And Music Transcription For The Irish Tin Whistle, Mikel Gainza, Robert Lawlor, Eugene Coyle, Aileen Kelleher

Conference papers

A technique for detecting tin whistle note onsets and transcribing the corresponding pitches is presented. This method focuses on the characteristics of the tin whistle within Irish traditional music, customising a time-frequency based representation for extracting the instant when a note starts and the music notation. Results show that the presented approach improves upon the existing energy based approaches in terms of the percentage of correct detections.

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