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2005

Conference papers

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Full-Text Articles in Engineering

Performance Evaluation Of Video Streaming With Background Traffic Over Ieee 802.11 Wlan Networks, Nicola Cranley, Mark Davis Oct 2005

Performance Evaluation Of Video Streaming With Background Traffic Over Ieee 802.11 Wlan Networks, Nicola Cranley, Mark Davis

Conference papers

There is an increasing demand for multimedia streaming applications over WLAN networks. MPEG-4 and H.264 are compression standards targeted at high-quality streamed multimedia services over wireless best-effort IP networks. However, the dynamic nature of wireless networks in terms of fluctuating bandwidth and time-varying delays makes it difficult to provide good quality streaming under such constraints. Multimedia streaming applications are a demanding and challenging service to deliver over wireless networks. There is a trade-off between the capacity of the wireless network and the quality of the multimedia streaming application. In this paper we investigate the effect the background traffic load has …


Performance Evaluation Of Resource Usage For Unicast Video Streaming Over Ieee 802.11 Wlan Networks, Nicola Cranley, Mark Davis Jul 2005

Performance Evaluation Of Resource Usage For Unicast Video Streaming Over Ieee 802.11 Wlan Networks, Nicola Cranley, Mark Davis

Conference papers

Multimedia streaming applications are a demanding and challenging service to deliver over wireless networks. Such services have a large impact on the resource requirements of the WLAN. However, there are many variables involved in video streaming, such as the video content being streamed, how the video is encoded and how it is sent. This makes the role of radio resource management and the provision of QoS guarantees extremely difficult. In this paper we investigate the network resource requirements for three scenarios: a single unicast video streaming session; multiple unicast video streaming sessions and finally multiple unicast streaming sessions in the …


An Assessment Of The Audio Codec Performance In Voice Over Wlan (Vowlan) Systems, Miroslaw Narbutt, Mark Davis Jul 2005

An Assessment Of The Audio Codec Performance In Voice Over Wlan (Vowlan) Systems, Miroslaw Narbutt, Mark Davis

Conference papers

In this paper we present results of experimental investigation into the performance of three audio codecs (ITU-T G.711, G.723.1 and G.729A) under varying load conditions on a Voice over WLAN system utilizing the IEEE 802.11b wireless LAN standard. The analysis is based upon a new technique for estimating user satisfaction of speech quality calculated from packet delay and packet loss/late measurements. We also demonstrate the importance of the de-jitter buffer playout scheme for insuring speech quality. From our results we conclude that the use of the G.711 audio codec in conjunction with the new adaptive playout scheme gives the highest …


Assessing The Quality Of Voip Transmission Affected By Playout Buffer Scheme, Miroslaw Narbutt, Mark Davis Jun 2005

Assessing The Quality Of Voip Transmission Affected By Playout Buffer Scheme, Miroslaw Narbutt, Mark Davis

Conference papers

Delay, echo, encoding scheme, and packet loss all influence perceived quality of conversational speech transmitted over packet networks. Therefore, the choice of a buffer algorithm cannot be solely based on statistical loss/delay trade-off metrics. Also subjective “listening tests” or the newer ITU-T PESQ method, which don’t consider the effect of mouth-to-ear delay are inappropriate. We proposed a method for assessing VoIP call quality by extending the ITU-T E-model concept. This method provides a direct link to perceived conversational speech quality by estimating user satisfaction from the combined effect of information loss, delay and echo.


Introducing Pvspitch: A Pitch Tracking Opcode For Csound, Alan O'Cinneide Jan 2005

Introducing Pvspitch: A Pitch Tracking Opcode For Csound, Alan O'Cinneide

Conference papers

An accurate pitch tracker has many useful applications, whether for creating interactive electroacoustic compositions, music transcription, ethnomusicological research and numerous others. Designed for the Csound sound synthesis and signal processing language, PVSPITCH is an opcode that can be utilised for such purposes. The opcode performs a mathemathical analysis upon Csound's phase vocoder data streams and from this examination, ascertains what it determines to be the signal's pitch. The algorithm handles well many types of signals, including those missing various harmonics, even a fundamental, and also signals with inharmonic partials. The only signal restriction are that it be single voiced, strongly …


Realising Electronic Purchasing In The Irish Construction Industry, Alan V. Hore, Roger West Jan 2005

Realising Electronic Purchasing In The Irish Construction Industry, Alan V. Hore, Roger West

Conference papers

The use of Information Communication Technologies (ICT) in construction purchasing has been sporadic and piecemeal. Very significant inefficiencies and problems still exist in both paper transactions and non-integrated electronic solutions. At the simplest level, the electronic transmission of business documents offers savings in paper and postage. By going a step further, businesses can make strides in communicating with their partners, at relatively low cost, through direct links between their computers. Existing ICT such as the Internet, Bar-Coding, Radio Frequency Tagging, Electronic Data Interchange (EDI), Electronic catalogs and Enterprise Resource Planning Software (ERP) have facilitated electronic commerce (EC) functionality within many …


A Survey Of Electronic Purchasing Practice In Ireland: A Perspective For The Irish Construction Industry, Alan V. Hore, Roger West Jan 2005

A Survey Of Electronic Purchasing Practice In Ireland: A Perspective For The Irish Construction Industry, Alan V. Hore, Roger West

Conference papers

There are many millions of trading documents (such as purchase orders, delivery notes and invoices) currently exchanged on paper in business to business (B2B) transactions, each having to be re-keyed as they pass between different locations and computer applications. Existing Information Communications Technologies (ICTs) such as the Internet, Bar-Coding, Radio Frequency Tagging, Electronic Data Interchange (EDI), Electronic catalogs and Enterprise Resource Planning Software (ERP) have facilitated electronic commerce (EC) functionality within many business sectors. However, the adoption of such technologies in the Irish construction industry has been very slow with only limited evidence of their application. The results of a …


Information Delivery On Mobile Devices Using Contour Icon Sonification, Charlie Cullen, Eugene Coyle Jan 2005

Information Delivery On Mobile Devices Using Contour Icon Sonification, Charlie Cullen, Eugene Coyle

Conference papers

This paper examines the use of musical patterns to convey information, specifically in the context of mobile devices. Existing mechanisms (such as the popularity of the Morse code SMS alert) suggest that the use of musical patterns on mobile devices can be a very efficient and powerful method of data delivery. Unique musical patterns based on templates known as Contour Icons are used to represent specific data variables, with the output rendering of these patterns being referred to as a Sonification of that data. Contour Icon patterns mimic basic shapes and structures, thus providing listeners with a means of categorising …


Comparison Of Signal Reconstruction Methods For The Azimuth Discrimination And Resynthesis Algorithm, Dan Barry, Robert Lawlor, Eugene Coyle Jan 2005

Comparison Of Signal Reconstruction Methods For The Azimuth Discrimination And Resynthesis Algorithm, Dan Barry, Robert Lawlor, Eugene Coyle

Conference papers

The Azimuth Discrimination and Resynthesis algorithm (ADRess) has been shown to produce high quality sound source separation results for intensity panned stereo recordings. There are however, artifacts such as phasiness which become apparent in the separated signals under certain conditions. This is largely due to the fact that only the magnitude spectra for the separated sources are estimated. Each source is then resynthesised using the phase information obtained from the original mixture. This paper describes the nature and origin of the associated artifacts and proposes alternative techniques for resynthesising the separated signals. A comparison of each technque is then presented.


Multi-Channel Audio Time-Scale Modification, David Dorran, Robert Lawlor, Eugene Coyle Jan 2005

Multi-Channel Audio Time-Scale Modification, David Dorran, Robert Lawlor, Eugene Coyle

Conference papers

Phase vecoder based approaches to audio time-scale modification introduce a reverberant artefact into the time scaled output. Recent techniques have been developed to reduce the presence of this artefact; however, these techniques have the effect of introducing additional issues relating to their application to multi-channel recordings. This paper addresses these issues by collectively analysing all channels prior to time-scaling each individual channel.


The Benefits Of Deploying It In The Material Procurement In Ready Mix Concrete In The Irish Construction Industry, Alan V. Hore, Roger West Jan 2005

The Benefits Of Deploying It In The Material Procurement In Ready Mix Concrete In The Irish Construction Industry, Alan V. Hore, Roger West

Conference papers

The current methods of processing orders, deliveries and invoices of concrete products in the construction industry is enormously inefficient, with vast quantities of paperwork, duplication of effort, scanning, re-keying and resolving mismatches between purchase orders, delivery dockets and invoices. This paper sets out results of a survey which reveals attitudes to Information Communication Technologies (ICT) in supporting the purchasing process in construction. The drivers and barriers to ICT use in construction purchasing is discussed from both the contractor‟s and supplier‟s perspective. The paper goes on to describe the outcome of a pilot study in which the efficiencies are investigated arising …


Simulation In Semiconductor Manufacturing Facilities, Amr Arisha, Paul Young Jan 2005

Simulation In Semiconductor Manufacturing Facilities, Amr Arisha, Paul Young

Conference papers

Semiconductor manufacturing is one of the most complex industries in terms of technology and manufacturing procedure. The life cycle of a semiconductor facility (FAB) has many phases, in their life cycle including capacity planning, new products introduction, variation of products/technologies, and decline phase. The complexity of the manufacturing and the external forces from markets and technology growth make predicting the effects of changes in the manufacturing system problematic. Simulation, if used correctly, is a powerful hands-on tool which may be used to give a better insight of the effect of engineering/management decisions on the performance of the manufacturing system. While …


An Examination Of The Effect Of Organisational Culture Of The Implementation Of Public-Private Partnership (Ppp) In Ireland, Louis Gunnigan, David Eaton Jan 2005

An Examination Of The Effect Of Organisational Culture Of The Implementation Of Public-Private Partnership (Ppp) In Ireland, Louis Gunnigan, David Eaton

Conference papers

This paper is concerned with identifying the organisational issues causing difficulty in the use of PPP and assessing the impact of PPP implementation on the organisational culture in the Irish public and private sectors. The authors address this issue by mapping the PPP process for one project type and comparing this process with that carried out in traditional procurement. Process differences through use of PPP are identified and organisational issues that have potential to impact on PPP success are assessed. Whilst the study undertaken is not extensive, it provides insight for initiators of PPP projects into the organisational issues that …


Trioson: A Graphical User Interface For Pattern Sonification, Charlie Cullen, Eugene Coyle Jan 2005

Trioson: A Graphical User Interface For Pattern Sonification, Charlie Cullen, Eugene Coyle

Conference papers

The TrioSon software allows users to map musical patterns to input data variables via a graphical user interface (GUI). The application is a Java routine designed to take input files of standard Comma Separated Values (CSV) format and output Standard Midi Files (SMF) using the internal Java Sound API. TrioSon renders output Sonifications from input data files for up to 3 user-defined parameters, allocated as bass, chord and melody instruments for the purposes of arrangement. In this manner each parameter concerned is distinguished by its individual instrumental timbre, with the option of rendering any combination of 1 to 3 parameters …


Information Delivery On Mobile Devices Using Boolean Sonification Patterns, Charlie Cullen, Eugene Coyle Jan 2005

Information Delivery On Mobile Devices Using Boolean Sonification Patterns, Charlie Cullen, Eugene Coyle

Conference papers

Sonification is the means by which non-speech audio can be used to convey information. Existing work has produced methods for delivering information in a wide range of fields, and recent work has considered the huge potential of mobile devices for Sonification. Boolean Sonification is a method of defining two related musical patterns as boolean conditions (true/false, yes/no etc.), such that one is considered contrary to the other by the listener. The final pattern set ideally comprises of two musical events that are closely enough related as to be considered a group, yet distinct enough to be perceived as separate entities. …


A Novel Framework For Radio Resource Management In Ieee 802.11 Wireless Lans, Mark Davis, Tristan Raimondi Jan 2005

A Novel Framework For Radio Resource Management In Ieee 802.11 Wireless Lans, Mark Davis, Tristan Raimondi

Conference papers

In this paper we address the need to characterize and quantify resource usage in IEEE 802.11 WLANs in order to support radio resource management. We present a compact and intuitive framework for performance characterization and resource utilization that is based upon the concept of MAC bandwidth components. These MAC bandwidth components are directly related to the transmission rate and serve to quantify the resource requirements associated with accessing the wireless medium. We also introduce a graphical technique for presenting these MAC bandwidth components that illustrates how WLAN stations interact in contending for access to the wireless medium. We demonstrate the …


Performance Analysis Of Network-Level Qos With Encoding Configuration For Unicast Video Streaming Over Ieee 802.11 Wlan Networks, Nicola Cranley, Mark Davis Jan 2005

Performance Analysis Of Network-Level Qos With Encoding Configuration For Unicast Video Streaming Over Ieee 802.11 Wlan Networks, Nicola Cranley, Mark Davis

Conference papers

Video streaming has a large impact on the resource requirements of the WLAN. However, there are many variables involved in video streaming, such as the video content being streamed, how the video is encoded and how it is sent. This makes the role of radio resource management extremely difficult. In this paper we investigate the effect that video encoding configurations has on the network resource requirements for unicast video streaming in a WLAN environment. We compare the network resource requirements of several content types encoded at various encoding configurations with varying I-frame frequencies, target encoding bit rates and hint track …


Onset Detection Using Comb Filters, Mikel Gainza, Bob Lawlor, Eugene Coyle Jan 2005

Onset Detection Using Comb Filters, Mikel Gainza, Bob Lawlor, Eugene Coyle

Conference papers

A technique for detecting note onsets using FIR comb filters which have different filter delays is presented. The proposed onset detector focuses on the inharmonic characteristics of the onset component and the energy increases of the signal. Both properties are combined by utilising FIR comb filters on a frame by frame basis in order to obtain an onset detection functions, which is suitable for detecting slow onsets. The proposed approach improves upon existing methods in terms of the percentage of correct detections in signal processing.


Drum Source Separation Using Percussive Feature Detection And Spectral Modulation, Dan Barry, Derry Fitzgerald, Eugene Coyle, Robert Lawlor Jan 2005

Drum Source Separation Using Percussive Feature Detection And Spectral Modulation, Dan Barry, Derry Fitzgerald, Eugene Coyle, Robert Lawlor

Conference papers

This papers presents a method for the separation and resynthesis of drum sources from single channel polyphonic mixtures. The frequency domain technique involves identifying the presence of a drum using a novel percussive feature detection function, after which the short-time magniture spectrum is estimated and scaled according to an estimated time-amplitude function derived from the percussive measure. In addition to producing high quality separation results, the method described is also a useful pre-process for drum transcription techniques such as Prior Subspace Analysis in the presence of pitched instruments.


Audio Time-Scale Modification Using A Hybrid Time-Frequency Domain Approach, David Dorran, Eugene Coyle, Robert Lawlor Jan 2005

Audio Time-Scale Modification Using A Hybrid Time-Frequency Domain Approach, David Dorran, Eugene Coyle, Robert Lawlor

Conference papers

Frequency-domain approaches to audio time-scale modification introduce a reverberant artefact into the time-scaled output due to a loss in phase coherence between subband components. Whilst techniques have been developed which reduce the presence of this artifact, it remains a source of difficulty. A method of time-scaling is presented that reduces the presence of the reverberation by taking advantage of some flexibility that exists in the choice of phase required so as to maintain horizontal phase coherence along frequency-domain subband components. The approach makes use of appealing aspects of existing time-domain and frequency-domain time-scaling techniques.


Onset Detection, Music Transcription And Ornament Detection For The The Traditional Irish Fiddle, Aileen Kelleher, Derry Fitzgerald, Eugene Coyle, Robert Lawlor, Mikel Gainza Jan 2005

Onset Detection, Music Transcription And Ornament Detection For The The Traditional Irish Fiddle, Aileen Kelleher, Derry Fitzgerald, Eugene Coyle, Robert Lawlor, Mikel Gainza

Conference papers

By combining techniques used in previous onset detectors, a system that detects note onsets in traditional Irish fiddle tunes has been implemented. The notes detected also include the most common types of ornamentation played by the fiddle. Ornaments are notes of extremely short duration, at most a fifth the length of a regular note. A Short Time Fourier Transform based sub-band technique, which previously gave good results for the Irish tin whistle, was modified to include a threshold approximation more suitable for the fiddle. This system has been tested on a database of real recorded fiddle tunes and good results …


Development Of A Computer-Based Violin Teaching Aid: Vitool, Jane Charles, Derry Fitzgerald, Eugene Coyle Jan 2005

Development Of A Computer-Based Violin Teaching Aid: Vitool, Jane Charles, Derry Fitzgerald, Eugene Coyle

Conference papers

This paper considers the development of a violin teaching aid, called ViTool, which is based on violin pedagogy, sound analysis, and comparison of beginner and good player recordings. It is a computer based teaching aid and will ultimately consist of at least four task dependent tools. Typical beginner faults have been identified and features, that best describe them for classification purposes, are considered. The ViTool is not intended as a replacement or electronic teacher, but as a teaching aid. Presently, it seems that no such violin learning aid or tool exists and an opportunity exists for the development of such …


Single Channel Source Separation Using Short-Time Independent Component Analysis, Dan Barry, Derry Fitzgerald, Eugene Coyle Jan 2005

Single Channel Source Separation Using Short-Time Independent Component Analysis, Dan Barry, Derry Fitzgerald, Eugene Coyle

Conference papers

In this paper we develop a method for the sound source separation of single channel mixtures using Independent Component Analysis within a time-frequency representation of the audio signal. We apply standard Independent Component Analysis techniques to contiguous magnitude frames of the short-time Fourier transform of the mixture. Provided that the amplitude envelopes of each source are sufficiently different, it can be seen that it is possible to recover the independent short-time power spectra of each source. A simple scoring scheme based on auditory scene analysis cues is then used to overcome the source ordering problem ultimately allowing each of the …


Non-Negative Tensor Factorisation For Sound Source Separation, Derry Fitzgerald, Matt Cranitch, Eugene Coyle Jan 2005

Non-Negative Tensor Factorisation For Sound Source Separation, Derry Fitzgerald, Matt Cranitch, Eugene Coyle

Conference papers

An algorithm for Non-negative Tensor Factorisation is introduced which extends current matrix factorisation techniques to deal with tensors. The effectiveness of the algorithm is then demonstrated through tests on synthetic data. The algorithm is then employed as a means of performing sound source separation on two channel mixtures, and the separation capabilities of the algorithm demonstrated on a two channel mixture containing saxophone, strings and bass guitar.


A Reference Guide To Smith Predictor Based Methods For The Compensation Of Dead-Time Processes, Aidan O'Dwyer Jan 2005

A Reference Guide To Smith Predictor Based Methods For The Compensation Of Dead-Time Processes, Aidan O'Dwyer

Conference papers

An extensive literature exists on the compensation of time delayed processes. These compensation methods may be broadly divided into parameter optimised controllers, in which the controller parameters are adapted to the controller structure (the most common such controller is the proportional integral derivative, or PID, controller), and structurally optimised controllers, in which the controller structure and parameters are adapted optimally to the structure and parameters of the process model. Important structurally optimised compensator strategies are the Smith predictor and its variations. The purpose of this paper is to extract the essence of the developments in design, tuning and implementation of …


Pid Controller Tuning Of Networked Computer Based Control Systems, Aidan O'Dwyer Jan 2005

Pid Controller Tuning Of Networked Computer Based Control Systems, Aidan O'Dwyer

Conference papers

This contribution discusses the use of PID controller tuning rules to assist in the implementation of network computer based control systems. Such systems typically have a variable time delay associated with the transfer of information. PID controller tuning rules can be directly implemented with minimal capital investment.


Dual-Band Monopole Antenna With Stagger-Tuned Arms For Broadbanding, Max Ammann, R. Farrell Jan 2005

Dual-Band Monopole Antenna With Stagger-Tuned Arms For Broadbanding, Max Ammann, R. Farrell

Conference papers

The paper describes a dual-band miniaturized printed monopole for integration in modern wireless systems. The printed monopole is augmented with two arms, resonant at slightly different frequencies, providing a broadened response for the upper band. The achieved bandwidth for the high band is 36%. These antennas are proposed for the emerging dual-mode multi-band WLAN transceivers, which operate over a wide range of bands as dictated by national authorities. Measured and simulated data, including return loss, antenna gain and radiation patterns, are presented. The numerical method employed was the finite integration technique.


Comparative Study Of Two Techniques For Determining Critical Frequency Response Characteristics, Niall O'Connor, Aidan O'Dwyer Jan 2005

Comparative Study Of Two Techniques For Determining Critical Frequency Response Characteristics, Niall O'Connor, Aidan O'Dwyer

Conference papers

The paper presents a review of a comparative study of two separate techniques for obtaining important frequency and time domain characteristics of a system consisting of a process in series with a PI/PID controller in closed loop. The first technique involves the use of a Pseudo Random Binary Sequence (PRBS) to obtain the closed loop frequency response of the system. This closed loop frequency information may then be manipulated to obtain both open loop frequency response information and process model parameters. A further mathematical simulation using Matlab may then be performed independent of the actual process in order to obtain …


Smith Predictor Structure Stability Analysis Using Mikhailov Stability Criterion, Pauline Sourdille, Aidan O'Dwyer, Eugene Coyle Jan 2005

Smith Predictor Structure Stability Analysis Using Mikhailov Stability Criterion, Pauline Sourdille, Aidan O'Dwyer, Eugene Coyle

Conference papers

As is well known, stability is an important requirement for control systems. Due to the nature of time-delay processes, common methods to evaluate stability may be difficult to use. In 1938, Mikhailov proved a frequency response criterion, which is sufficient and necessary for the stability of processes described by known n-th order constant coefficient linear differential equations. This paper presents the Mikhailov method and the application of this method to a Smith predictor structure controlled by a PI controller.


Estimation Of The Parameters Of A Delayed Process Using Open Loop Time Domain Techniques, Yue Zhang, Aidan O'Dwyer Jan 2005

Estimation Of The Parameters Of A Delayed Process Using Open Loop Time Domain Techniques, Yue Zhang, Aidan O'Dwyer

Conference papers

All process investigations should start by a determination of the process model. The modeling strategy used will influence the value of the model parameters, which will in turn affect the controller values determined from tuning rules. This paper will describe an analytical method to identify a model of the dynamic characteristics of a process with a delay by using a tangent and point method, as originally suggested by Murrill, 1967. The methodology has been applied to eight benchmark transfer functions suitable for testing PID controllers, as suggested by Åström and Hägglund, 2000. The main advantages of the modeling approach are …