Digital Commons Network^™

Novel Implementation Of An Adaptive Shared Control Braking System For A Wheeled Walking Aid, Eileen Young

Masters

The focus of this thesis is to design, build and control a prototype walking aid. The frame of the prototype is based on a combination of features from standard, widely available, wheeled walking aids. The user drives the walking aid. New brakes are added to facilitate accurate sensitive controlled stopping of the aid either by the user or automatically. The braking is achieved by the novel use of hydraulic disc brakes as used on mountain bicycles. Braking force is modulated via a linear actuator stepping motor controlled by a local drive. Actualisation of control of both stepping motor and supervisor …

Performance And Robustness Metrics For The Compensation Of Processes With Time Delay, Niall O'Connor

Masters

Proportional-integral (PI) or proportional-integral-derivative (PID) controllers are still by far the most common form of automatic feedback control employed in the process industries at present. It is estimated that more than 90% of control loops in the process control industry are of the PID type. Unfortunately, it is a common occurrence, in the majority of industries where this type of control is employed, for the performance of PI/PID controlled processes to be poor. There are a number of factors influencing this poor performance, namely controller tuning problems, controller equipment design restrictions, deficiencies in control strategy design, etc. The research was …

Optimum Design Of The Printed Strip Monopole, Max Ammann, Matthias John

Articles

A monopole antenna, printed on low-cost laminate and fed by a microstrip line, is examined. These types of antennas are becoming popular in view of their broad bandwidth and low-profile structure, enabling easy integration as a terminal antenna. The move away from a classical ground plane (with normal radiator) is one of the attractive features of these antennas, but the full effects of the radiator and ground plane being on opposite sides of the same laminate are often not investigated. The effect of these ground planes on the impedance bandwidth and radiation pattern is investigated experimentally and numerically.

The Effect Of The Internal Field On The Ir Absorption Spectra Of Small Particles In Case Of 3d, 2d And 1d Size Confinement, Igor I. Shaganov, Tatiana S. Perova, R. Alan Moore, Kevin Berwick

Articles

The spectral properties of composite materials based on small particles under 1D, 2D, and 3D size confinement are described using a combination of dispersive internal field and effective media theory approaches. Calculations performed for a number of crystalline materials have shown that the peak position and intensity of the vibrational band of the material under conditions of 1D, 2D, and 3D size confinement are changed, whereas the bandwidth of the band remains the same. In the case of 3D confinement, the peak position of the spectrum of isolated “mesoparticles” ( ) appears to be very close to the intrinsic frequency …

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

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.

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 …

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 …

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.

Design Of A Wireless System For Patient-Hospital Communciation And Result Validation In Point Of Care Testing, John Mcgrory, Owen Lynch, Eugene Coyle

Conference papers

This paper discuses mobile phone (cell phone) and wireless applications for linking patients who manage their healthcare outside the hospital using point of care testing (POCT) to hospital information systems (HIS). Certain medical conditions require patients to manage their healthcare by performing on themselves POC testing and act faithfully on the result. This raises quality control issue, as these POC samples and testing procedures are not independently overseen by professional hospital staff. In hospitals, samples taken by clinicians are validated by hi-tech computerised validation systems to ensure plausibility, before physicians rely on them. Patients in the home must often use …

Experimental And Numerical Investigation Of Therapeutic Ultrasound Angioplasty, Graham Gavin, M.S. J. Hashmi, Garrett B. Mcguinness

Other resources

Therapeutic ultrasound angioplasty is an emerging minimally invasive cardiovascular surgical procedure that involves the delivery of ultrasonic displacements to the distal-tip of small diameter wire waveguides. The ultrasonic distal-tip displacements affect atherosclerotic plaque and thrombus by direct contact ablation, pressure wave components and cavitation, in addition to an acoustic streaming event around the distal-tip. This study uses experimental and numerical methods to investigate ultrasonic displacements in wire waveguides and the effect the distal-tip displacements have on the surrounding fluid. An experimental therapeutic ultrasound wire waveguide apparatus is described that delivers displacements to the distal-tip of 1.0 mm and tapered 0.35 …

An Acoustic Fluid-Structure Simulation Of A Therapeutic Ultrasound Wire Waveguide Apparatus, Graham Gavin, M. Hashmi, Finbar Dolan, Garret Mcguinness

Conference Papers

The use of high-power low-frequency ultrasound transmitted down small diameter wire waveguides is an emerging technology that may have potential in the treatment of complicated atherosclerotic plaques in cardiovascular surgery. This form of energy delivery results in vibrating the distal-tip of the wire waveguide disrupting material by means of direct contact ablation and also cavitation, pressure waves and acoustic streaming in the surrounding fluid. This work describes a numerical acoustic fluid-structure model of the ultrasound wire waveguide and blood surrounding the distal tip. The structural analysis of the model predicts the natural frequencies of the waveguide and shows the extent …

An Acoustic Fluid-Structure Simulation Of A Theraputic Ultrasound Wire Waveguide Apparatus, Graham Gavin, M.S. Hashmi, Finbar Dolan, Garrett Mcguinness

Conference Papers

The use of high-power low-frequency ultrasound transmitted down small diameter wire waveguides is an emerging technology that may have potential in the treatment of complicated atherosclerotic plaques in cardiovascular surgery. This form of energy delivery results in vibrating the distal-tip of the wire waveguide disrupting material by means of direct contact ablation and also cavitation, pressure waves and acoustic streaming in the surrounding fluid. This work describes a numerical acoustic fluid-structure model of the ultrasound wire waveguide and blood surrounding the distal tip. The structural analysis of the model predicts the natural frequencies of the waveguide and shows the extent …

Electronic Speckle Pattern Shearing Interferometry For Nondestructive Testing Of Thermal Sprayed Alloy Coatings, Qiang Xue

Conference Papers

Thermal sprayed coatings have wide engineering applications. There now exists a wide range of destructive and nondestructive testing (NDT) methods for surface coating inspections. This paper describes an application of electronic speckle pattern shearing Interferometry (ESPI) for NDT of thermal sprayed surface coatings. In contrast to other conventional methods such as eddy current,ultrasonic or X-ray, ESPSI allows fast and large survey area inspection. Experimental results of shearographic measurements are presented. Thermal sprayed coatings were tested using ESPI. Delaminations of the coatings were detected and the fringe patterns were captured using this method. It is shown that the shearography technique can …

A Gap Model For Understanding The Variation Of The Real Product From The Ideal, Kevin Delaney, Pat Phelan, Declan Delaney

Conference Papers

Clients have an idealised view of the appearance and functionality of the products they are sourcing. Their product requirements vary according to their specific circumstances and experiences. When designers try to meet or surpass client expectations, variation results and the product will deviate from the client’s idealised view. This often results in frustration, disappointment and rework for everyone concerned. Consequently designers must understand the sources of variation affecting their products and the techniques and tools that they can employ to reduce the negative effects of this variation. This paper examines the factors influencing clients as they formulate their expectations. It …

An Investigation On The Suitability Of Surface Engineered Austempered Ductile Iron As A Gear Material, M. Grech, David Kennedy, Zdravko Schauperl

Conference Papers

This preliminary study demonstrates that surface engineered austempered ductile iron is a valid alternative gear material to carburised steel. The impact energy of ductile cast iron samples in various conditions, including as – cast, austempered at 240^oC and austempered and shot peened using both 0.7mm and 1.4mm steel balls, was measured. As expected the as-cast material exhibited nominal impact energy. This has been attributed mainly to the pearlitic matrix structure.Austempering generally increases the impact energy. The extent of the improvement is however dependent on the austempering temperature and the resulting microstructure. It was shown that the structure following …

Dit Independent, 1st.-31st. Of January, 2005, Dit:Students Union

DIT Student Union

No abstract provided.

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 …

Study Of An Acrylamide-Based Photopolymer For Use As A Holographic Data Storage Medium, Hosam Sherif, Izabela Naydenova, Suzanne Martin, Colm Mcginn, G Berger, C Denz, Vincent Toal

Conference Papers

An acrylamide-based photopolymer formulated in the Centre for Industrial and Engineering Optics has been investigated with a view to further optimisation for holographic optical storage. Series of 15 to 30 gratings were angularly multiplexed in a volume of the photopolymer layers with different thickness at a spatial frequency of 1500 lines/mm. Since the photopolymer is a saturable material, an exposure scheduling method was used to exploit the entire dynamic range of the material and allow equal strength gratings to be recorded. From this investigation the photopolymer layer’s M/# was determined with regard to the recording geometry used. The temporal stability …

Holographic Recording Of Patterns In Thin Film Acrylamide-Based Photopolymer, Izabela Naydenova, Kotakonda Pavani, Emilia Mihaylova, Katia Loudmer, Suzanne Martin, Vincent Toal

Conference Papers

A study of the light induced surface relief modulation in thin photopolymer layers is reported. Due to the nature of the photopolymer used no additional post-processing is required after holographic recording. An investigation of the dependence of the amplitude of the photoinduced relief modulation on different parameters of recording such as spatial frequency, intensity of the beams and times of exposure has been carried out. The surface relief modulation is characterized by white light interferometry. Photopolymer layer thickness ranges from 1-5m. A model of the mechanism of surface relief formation is proposed on the basis of the measured dependencies. A …

Investigation Of Polymerization Rate In An Acrylamide-Based Photopolymer Using Raman Spectroscopy, Raghavendra Jallapuram, Izabela Naydenova, Hugh Byrne, Suzanne Martin, Robert Howard, Vincent Toal

Conference Papers

Diffusion models predict that polymerization and diffusion rates are the key factors that control the dynamics and the final properties of a holographic grating recorded in a photopolymerizable material. Diffusion rates during the initial phase of holographic recording have already been studied and reported. We now report the investigation of the polymerization rate in an acrylamide-based photopolymer using Raman spectroscopy. The polymerization rate constant was estimated by monitoring the intensity of the characteristic Raman peaks at 1284 cm-1 corresponding to the bending mode of CH vinyl bond in acrylamide and 1609 cm-1 corresponding to the carbon-carbon double bond (C=C) in …

An Exploration Of The Internationalisation Process Of Irish Indigenous Software Smes, Kathy Keeney

Masters

From meagre beginnings in the 1970s, the Irish software industry has emerged as one of the most interesting, exciting and successful Irish internationally traded service industries. Some thirty years later, the industry is still characterised by high levels of international trade activity, through niche market orientation and innovative and flexible management. Through an exploration of the internationalisation process in the context of Irish indigenous software firms, this thesis seeks to understand how this process of international expansion occurs, the barriers encountered throughout the process, future challenges for the industry and the use of strategic partnership activities as a facilitator in …

Green Engineering Services Limited, Gerry Mortimer

Case studies

“Sometimes in my darker moments I think that, if I had ducks they’d drown, and this is one of those moments. You will have heard the announcement that Fruit of the Loom are closing down the remainder of their operations in the northwest”, Manus Green said, discussing his latest predicament with his friend and occasional advisor Paul Staunton. Manus with his wife Claire, was owner of Green Engineering Services Ltd., a small precision engineering company based on an industrial estate in West Donegal.

General Records (Ireland), Thomas Cooney

Case studies

Standing outside a pub, Billy Barrett and Martin Murphy faithfully obeyed the no smoking ban that was now a feature of the Irish social scene. As they smoked their cigarettes, they discussed the singer/songwriter who played inside the premises that they stood against so nonchalantly. The gig was enjoying a great reception, with the crowd enthusiastically applauding the eclectic mix of blues, rock, and traditional music. ‘Well, Billy, how would fancy starting a record company?’ asked Martin, as if it was not really a challenge. ‘The singer playing inside wants to record a CD but she has no label. I …

Developing A Participatory Consultation Process For Quality Reviews: The Initial Stage Of The European University Associations Quality Review Of The Dublin Institute Of Technology, Aidan Kenny

Level 3

This paper describes the evolution of a consultation process utilized by the Dublin Institute of Technology (DIT) as part of a quality review process. An emphasis is placed on outlining: the collaborative nature of the enquiry; the guidelines and code of ethics adopted; the social research methodology utilized both quantitative (online surveys, staff n=1831, student’s n=21094) and qualitative (6 staff focus groups n=45 and 4 stakeholder focus groups n=24 and faculty board submissions 6). Instrument construction, theme sheet design and sampling procedures and response rate are detailed. The author, as consultation facilitator, provides an narrative of events and applies theory …

Capitalising On Culture: An Evaluation Of Culture-Led Urban Regeneration Policy, Luke Binns

Articles

Municipal authorities throughout Western Europe are attempting to drive regeneration of their urban centres through policies designed to attract inward investment and tourism. In an attempt to woo these outside economic agents in, a variety of cultural consumption oriented policies have been developed and marketed. These include investment in hard cultural-infrastructure such as museums or art galleries, and in less physical aspects such as holding events like the European Capital of Culture. A polemical debate surrounds this use of cultural policy with a clearly economic agenda. This paper gives a brief synopsis of some culture-led regeneration models, addresses the validity …

Critting The Crit In The Education Of Architects: From Bauhaus To Bolton Street, Patrick Flynn

Theses

This investigative study is concerned with examining the current methods of assessment of architecture students in the system known as the “crit” and the associated methods of giving students feedback on their designs in a public forum. The aim of the research is to identify the main weaknesses of the crit system and to explore alternatives which perhaps would have more sustainable and transparent methods of assessment and feedback. Personal motivation for the research sprang from concerns regarding both the effectiveness of the crit from the pedagogical perspective of student learning and from concerns about it as a transparent and …

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 …

Design Of Mobile Phone Applications For Point-Of-Care Test Result Validation., John Mcgrory, Owen Lynch, Eugene Coyle

Conference Papers

Patients with many different conditions are required to take the management of their condition into their own hands and perform Point of Care Testing (POCT) at home. However, this raises quality control issues that would not arise in a clinical setting, since the sample acquisition and testing procedures are not overseen by professional hospital staff. Another major issue, the main focus of this research, is that results from such tests are not clinically validated to ensure that they are plausible for that patient at the time of testing. In hospital, tests taken by clinicians are validated by hi-tech computerised validation …

Economic Audit Of South Dublin County 2004, Phil Mulvaney, Nigel Donnelly

Other Resources

The main objective of this report is to provide an audit of the assets of South Dublin County with a view to assisting South Dublin County Development Board in the preparation of an economic strategy for the county. The recommendation to undertake such an audit was outlined as a key priority in South Dublin: A Place for People - An Integrated Strategy for the Economic, Social and Cultural Development of South Dublin County 2002-2012, a report of the South Dublin County Development Board.

The report is divided into seven main parts. Part 1 provides a contextual overview of the county, …

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.