Engineering Commons^™

Modelling And System Identification For Real Systems, Karolyn Murphy

Theses

The field of system identification and process parameter estimation is an area that has developed rapidly during the past few decades. The approach to the system identification problem can be influenced by many different aspects which include the specific purpose of the identification. In this thesis, system identification for the purpose of controller design is the central theme.

Initially, the work will focus on a number of approaches to real system identification. Particular attention will be made to the classical non-parametric techniques and the more modern parametric estimation techniques using both open- and closed-loop real-time data. A voltage controlled dc …

Address Assignment In Ad-Hoc Networks, John Paul O'Grady

Theses

A wireless ad-hoc network is a collection of autonomous nodes or terminals that communicate with each other by forming a multi-hop radio network and maintaining connectivity in a decentralised manner. In an ad hoc network routing is used to find and maintain a path through the network. Routing requires each node to have a unique identifier, to ensure that packets sent to a particular node reach their intended destination. Most ad-hoc routing protocols assume that a node already has an address prior to its entry into a network and so the issue of address assignment is largely ignored. This however …

Performance Estimation Of A Sip Based Push-To-Talk Service For 3g Wireless Networks, Eoin O'Regan

Theses

Push To Talk (PTT) services have been in existence for several decades providing dispatch services via two-way radio such as walkie-talkies. For a number of years now PTT services have been available for use over mobile phone networks. These mobile PTT services have occupied a niche market with business users and have been provided on proprietary networks that do not enable roaming.

Over the past year there has been an explosion of interest in the concept of PTT provided over mobile networks using Internet Protocol (IP) technology. This service uses cellular access and radio resources more efficiently than circuit-switched cellular …

Enhancement Of Linear Prediction Coefficient Quantisation In The 3g Adaptive Multi Rate Speech Coder, John Raymond Mccarthy

Theses

Most speech coding algorithms in use today utilise the source-filter model of human speech production in which speech is modelled as the response of a time varying, linear, all-pole, synthesis filter to an input excitation. In mobile communications, it is the coefficients of this filter and details of the excitation that are transmitted. The filter coefficients are first quantised using a limited number of bits. Due to coefficient sensitivity, direct quantisation of the filter coefficients may lead to an unstable filter during speech synthesis at the receiver and hence an alternative representation is needed. Line Spectral Frequencies (LSFs) have evolved …

A Sip Based Multimedia Messaging Service, Donna Griffin

Theses

The Session Initiation Protocol (SIP) is the protocol of choice for establishing multimedia sessions in Universal Mobile Telecommunications System (UMTS) networks as stated by 3GPP. SIP is a protocol that will merge together the cellular and Internet worlds and is also scalable, highly available and extensible. It enables mobile carriers to extend operations, administration, maintenance and provisioning (OAMP) in one application to all applications. In addition, while SIP permits presence. Instant Messaging, File Sharing etc., its ultimate value lies in seamlessly aggregating these applications in more powerful offerings, such as Multimedia Messaging, Push to Talk and Voice over IP.

Multimedia …

Ground-Source Heat Pumps In Ireland: Heat Transfer Experimentation For The Design And Modelling Of A Sub-Slab Installation., Sarah O'Connell

Theses

Ground-source heat pump technology is currently undergoing rapid growth in Ireland. Three aspects of ground-source heat pumps have been studied in this thesis. The market expansion taking place in Ireland, heat transfer from the soil to the pipe of a ground- source heat pump collector, and the design of an innovative sub-slab ground-source heat pump system.

Initial investigations into the use of ground-source heat pumps in Ireland revealed surprising growth in the use of the technology. There have been approximately 1500 systems installed mainly since 2000. The ground-source heat pump market in Ireland has an estimated annual growth rate of …

Development Of A Low Jitter Multiplying Delay Locked Loop, Ian Kennedy

Theses

The clock generator is a critical component in high-speed wireline communication systems. The clocks in these systems mark time at precise regular intervals. Any deviation of the clock edges from these ideal time points is called jitter and it degrades the overall integrity of the communication system. This thesis looks at both phase locked loops (PLLs) and delay locked loops (DLLs) and their ability to provide these precise clocks. Expressions for the thermal noise-induced jitter in both the PLL and DLL are compared. From this, the DLL is shown to possess the potential for better jitter performance. However, to realise …

Optimisation Of Heat Transfer And Fluid Flow In The Cooling Of Building Integrated Photovoltaic Facades., Eoin Patrick Hodge

Theses

The aim of this research was to explore the effects of mature and developing technologies from aeronautical industries such as impingement and film cooling, and electronic cooling techniques, in the setting up of different laminar and turbulent flow regimes on PV cooling duct heat transfer rates, with air flow as that brought about with natural buoyancy effects in a vertical building facade. The problem of efficiency losses in PV panels, due to overheating, is one of the factors restricting the development and use of this renewable power source. PV panels can experience very high temperatures, due to the heat input …

Delivery Of Wireless Ad Hoc Services Using Jini, Sinead Cummins

Theses

Traditionally, networks were planned infrastructures consisting mainly ot desktop machines and servers. As a result of the careful planning carried out prior to their construction, these networks were easily managed and controlled by network administrators. Today these networks are joined by cell phones, PDAs and other handheld devices as well as a host of sensors. This has led to a migration from traditional networks to ad hoc networks.

One way to envisage what this new environment will be like is to imagine what life will be like at the edge of the network. Today the edge mostly consists ot clients …

A Service-Based Architecture For Learning Management Systems Which Supports Personalisation And Collaboration, Markus Schmid

Theses

This work develops a service-based architecture for an extensible and customisable learning management system (LMS) runtime environment. The architecture mainly defines interfaces for the interaction of functional system components represented by loosely coupled distributed services. Services that represent functional components of the distributed LMS are called e-leaming services. In addition, underlying infrastructure services provide supportive functionality such as service-lookup within an institution. Users access the system using an LMS portal component that acts as a front-end for the LMS services.

While existing e-leaming environments provide a relatively good coverage of most of the functional requirements defined in this work, they …

Closed Material Cycles And Organic Solvent Recovery, Tim De Jong

Theses

A survey was conducted of the pharmaceutical sector in Ireland to establish organic solvent usage, recovery and treatment practices. The eleven companies covered by the survey, which included several of the worlds largest multinational companies, consumed in the region of 122,000 tonnes of organic solvent in 2002. Approximately 53,000 tonnes was recovered on-site while 69,000 tonnes of virgin solvent was brought on-site to replace that which was lost through wastewater treatment, incineration, fugitive emissions and off-site treatment or reuse. The total quantity of virgin solvent consumed by the eleven companies accounted for 75.4 % of organic solvent imports to Ireland. …

Magneto-Acoustic Emission Analysis Of Microstructural Change In Aisi 430 And Aisi 304 Stainless Steel, Denis O'Sullivan

Theses

Magneto-acoustic emission (MAE) is a relatively new non-destructive detection technique. Its working principle is based on Barkhausen discontinuities and magnetostriction within a ferromagnetic material that is subjected to a varying magnetic field. Magneto-acoustic emission (MAE) and magnetic Barkhausen noise (MBN) sensing techniques were developed and employed to characterise plastically deformed and heat-treated AISI 430 ferritic stainless steel and AISI 304 austenitic stainless steel samples. A new waveform measurement parameter for magneto-acoustic emission was developed called MAE (Absolute “energy”).

Both MAE and MBN were found to decrease with increasing plastic deformation of AISI 430. MAE (Absolute “energy”) and MBN (RMS) were …