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Conference papers

2004

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Full-Text Articles in Engineering

Intelligent Simulation-Based Lot Scheduling Of Photolithography Toolsets In A Wafer Fabrication Facility, Amr Arisha, Paul Young Dec 2004

Intelligent Simulation-Based Lot Scheduling Of Photolithography Toolsets In A Wafer Fabrication Facility, Amr Arisha, Paul Young

Conference papers

Scheduling of a semiconductor manufacturing facility is one of the most complex tasks encountered. Confronted with a high technology product market, semiconductor manufacturing is increasingly more dynamic and competitive in the introduction of new products in shorter time intervals. Photolithography, being one of the processes repeated often, is a fabrication bottleneck. Lot scheduling within photolithography is a challenging activity where substantial improvements in factory performance can be made. The proposed scheduling methodology integrates two common approaches, simulation and artificial intelligence. Using detailed simulation modeling within a structured modeling method, a comprehensive model to characterize the photolithography process was developed. An …


A Multi-Criteria Approach To The Evaluation Of Aviation E-Marketplace Portals, Edward Sweeney, Emilio Esposito, Pietro Evangelista, Michel Mastroianni, Renato Passaro, Claudia-Maria Wagner Sep 2004

A Multi-Criteria Approach To The Evaluation Of Aviation E-Marketplace Portals, Edward Sweeney, Emilio Esposito, Pietro Evangelista, Michel Mastroianni, Renato Passaro, Claudia-Maria Wagner

Conference papers

After a proliferation of logistics e-Marketplaces during the dot.com boom of 1998-2000, there has been a high rate of failure and survivals are developing much more slowly than expected. This is the case of aviation industry where a large number of B2B e-Marketplaces emerged according to the focus of aviation companies’ strategies on electronic B2B in the late 1990s. However, the current use of e-Marketplaces in the industry is low and many of them have ceased trading. The traditional e-Marketplaces model have been characterised by poor quality of portals and the lack of technical standards. Such an approach is unsustainable …


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.


Analysis Of Data Sets Using Trio Sonification, Charlie Cullen, Eugene Coyle Jan 2004

Analysis Of Data Sets Using Trio Sonification, Charlie Cullen, Eugene Coyle

Conference papers

Recent advances in technology have suggested that sound and audio play a far greater part in our daily working lives than ever before. Mobile phone ring tones are now based upon polyphonic music sequences that allow relatively complex audio to be generated from a handset by way of conveying information (i.e. a call or message is incoming). This real world example of sonification suggests that far more could be made of sonification techniques for analysis- particularly in the business environment. One advantage of sonification is its relatively hands free nature in that once a sequence is being played it does …


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 …


Time-Scale Modification Of Music Using A Synchronized Subband/Time-Domain Approach, David Dorran, Robert Lawlor Jan 2004

Time-Scale Modification Of Music Using A Synchronized Subband/Time-Domain Approach, David Dorran, Robert Lawlor

Conference papers

Time-domain audio time-scaling algorithms are efficient in comparison to their frequency-domain counterparts, but they rely upon the existence of a quasi-periodic signal to produce a high quality output. This requirement makes them unsuitable for direct application to complex multi-pitched signals such as polyphonic music. However, it has been shown that applying time-domain algorithms on a subband basis can resolve this issue. Existing subband/time domain approaches result in a reverberant/phasy artifact being introduced into the output due to poor synchronization between time-scaled subbands. This paper presents a number of synchronization schemes that greatly reduce the amount of reverberation/phasiness introduced into the …


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 …


Towards A Computer Assisted Violin Teaching Aid, Derry Fitzgerald, Jane Charles, Eugene Coyle Jan 2004

Towards A Computer Assisted Violin Teaching Aid, Derry Fitzgerald, Jane Charles, Eugene Coyle

Conference papers

This paper presents a possible approach for developing a violin teaching aid based on violin pedagogy, sound analysis and comparison of beginner and good player recordings. This teaching aid is targeted at students who have difficulty listening attentively to the sounds they produce. It aims to draw their attention to the sound of a fault, offer correction and to train the user's ear to actively listen.


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 …


Enabling The Re-Engineering Of Material Purchasing In The Construction Industry By The Effective Use Of Information Technology, Alan V. Hore, Roger West Jan 2004

Enabling The Re-Engineering Of Material Purchasing In The Construction Industry By The Effective Use Of Information Technology, Alan V. Hore, Roger West

Conference papers

The current methods of ordering, delivering and invoicing of materials in the construction industry is enormously inefficient, with vast quantities of paperwork, duplication of effort, scanning, re-keying and resolving mismatches between invoices, delivery dockets and purchase orders. This paper sets out the results of a successful 2005 pilot project which achieved a three-way electronic match of the purchase order, delivery note and supplier invoice information. The paper goes on to describe the opportunities and challenges of introducing such a system in the Irish construction industry


Thin-Film Simulation Model For Comparing Production Schedules In A Semiconductor Fabrication Facility, Amr Arisha, Paul Young Jan 2004

Thin-Film Simulation Model For Comparing Production Schedules In A Semiconductor Fabrication Facility, Amr Arisha, Paul Young

Conference papers

Analysis of advanced manufacturing systems in any manufacturing industry requires certain level of knowledge about the system. Flexible manufacturing cells, in particular, are commonly used in most wafer fabrication to provide the ability to change product without requiring the construction of new manufacturing plant. This level of flexibility comes at a significant capital cost and, in order to achieve the maximum potential of each cell, it is essential to characterize and establish the performance of these cells in detail before a new production plan is implemented. Using state-of-the-art computer simulation and a structured modelling methodology a generic model of flexible …


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 …


A Proposal For Re-Engineering The Procurement Of Building Materials By Effective Use Of Ict, Alan V. Hore, Roger West Jan 2004

A Proposal For Re-Engineering The Procurement Of Building Materials By Effective Use Of Ict, Alan V. Hore, Roger West

Conference papers

This paper seeks to establish the case for re-engineering the procurement of materials in the Irish construction industry. The authors make their observations from witnessing, first-hand, the operation of a purchasing function in a large contracting organisation in the Republic of Ireland. The authors identify the core problems that exist in the current mainly paper-based process and present a strong case for the re-engineering of the process by the adoption of a fully integrated Information Communications Technology (ICT) solution


Orchestration Within The Sonification Of Basic Data Sets, Charlie Cullen, Eugene Coyle Jan 2004

Orchestration Within The Sonification Of Basic Data Sets, Charlie Cullen, Eugene Coyle

Conference papers

The use of sonification as a means of representing and analysing data has become a growing field of research in recent years and as such has become a far more accepted means of working with data. Existing work carried out as part of this research has focused primarily on the sonification of DNA/RNA sequences and their subsequent protein structures for the purposes of analysis. This sonification work raised many questions as regards the need for sequences to be set to music in a standard manner so that different strands could be analysed by comparison, and hence the orchestration and instrumentation …


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 …


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 …


Optimal Control Strategy Of Upqc For Minimum Operational Losses, Malabika Basu, Michael Farrell, Michael Conlon, Kevin Gaughan, Eugene Coyle Jan 2004

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 Jan 2004

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 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.


Enhancing Process Performance Through Automatic Control, Aidan O'Dwyer Jan 2004

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 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.


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.


Determination Of The Phase Of A Transfer Function: Theory Versus Practice, Pauline Sourdille, Aidan O'Dwyer Jan 2004

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 Jan 2004

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 Jan 2004

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 …


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 …


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.


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 …


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.


Harmonic Distortion Caused By Ev Battery Chargers In The Distribution Systems Network And Its Remedy, Malabika Basu, Kevin Gaughan, Eugene Coyle Jan 2004

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 …