Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 10 of 10

Full-Text Articles in Engineering

Development Of Exponential-Fitted Numerical Methods For Building Energy Simulation, Michael Crowley, Saleem Hashmi Jan 2000

Development Of Exponential-Fitted Numerical Methods For Building Energy Simulation, Michael Crowley, Saleem Hashmi

Conference papers

Simulation of energy flows in buildings is computationally intensive. Consequently, improvements in computing power and algorithm efficiency can always be utilized. Commonly used implicit solvers require extensive matrix processing while standard explicit methods have limited stability and progress in very small time increments. In this work, a number of stable numerical methods are examined which are explicit in nature and therefore do not require the use of matrices. One such algorithm and two proposed developments of it are assessed using a building related test problem prepared for this purpose, and their performances are compared with that of an efficient implicit …


Structural Properties And Stress Analysis Of Sio2 Thin Films, G. Joyce, C. Moore, T. S. Perova, C. Beitia, A. Kocot, Kevin Berwick, Hugh Byrne, J. M. Mcgilp Jan 2000

Structural Properties And Stress Analysis Of Sio2 Thin Films, G. Joyce, C. Moore, T. S. Perova, C. Beitia, A. Kocot, Kevin Berwick, Hugh Byrne, J. M. Mcgilp

Conference papers

Wet and dry oxidations of (111) crystalline silicon wafers were performed at temperatures between 900°C and 1150°C and subsequently annealed at 700°C. Process parameters such as the withdrawal rate from the furnace and annealing time were varied and the effect on the oxide layer are discussed. The magnitude and nature of the stress in the wafers after thermal oxidation was analysed using micro-Raman spectroscopy. The Full Width at Half Maximum (FWHM) of the Raman peak at ~ 520 cm-1 was also analysed to extract information relating to crystal disorder and defect density caused by the oxidation process. The results obtained …


Small Planar Monopole Covers Multiband Brans, Max Ammann, L. E. Doyle Jan 2000

Small Planar Monopole Covers Multiband Brans, Max Ammann, L. E. Doyle

Conference papers

The use of a single antenna which can cover a wide range of frequencies is a desirable feature for future wireless communications systems. The emerging self-organising and ad-hoc networks require more than an octave of bandwidth to facilitate multiband operation. A shorted planar monopole antenna is optimised for future wireless networking bands by suitable choice of planar dimension and feedgap separation. The antenna offers a return-loss greater than 10 dB from 1.60 GHz to 5.90 GHz. The radiation pattern is shown to be quasi-omnidirectional within the 10 dB return-loss bandwidth. Antenna properties are compared with the simple planar monopole.


Dead-Time Compensators: Performance And Robustness Issues, James Syder, Thomas Heeg, Aidan O'Dwyer Jan 2000

Dead-Time Compensators: Performance And Robustness Issues, James Syder, Thomas Heeg, Aidan O'Dwyer

Conference papers

This paper will compare a number of PID and predictive controller strategies to compensate processes modelled in first order lag plus time delay (FOLPD) form. The performance and robustness of the resulting compensated systems are evaluated analytically (where appropriate) and in simulation.


Time Delayed Process Model Parameter Estimation: A Classification Of Techniques, Aidan O'Dwyer Jan 2000

Time Delayed Process Model Parameter Estimation: A Classification Of Techniques, Aidan O'Dwyer

Conference papers

An extensive though scattered literature exists on the estimation of the model parameters of time delayed processes. However, it is possible to identify themes that are common to many of the proposed techniques. The intention of this paper is to provide a framework against which the literature may be viewed.


A Summary Of Pi And Pid Controller Tuning Rules For Processes With Time Delay. Part 1: Pi Controller Tuning Rules, Aidan O'Dwyer Jan 2000

A Summary Of Pi And Pid Controller Tuning Rules For Processes With Time Delay. Part 1: Pi Controller Tuning Rules, Aidan O'Dwyer

Conference papers

The ability of proportional integral (PI) and proportional integral derivative (PID) controllers to compensate many practical industrial processes has led to their wide acceptance in industrial applications. The requirement to choose either two or three controller parameters is perhaps most easily done using tuning rules. A summary of tuning rules for the PI control of single input, single output (SISO) processes with time delay is provided in this paper.


Additional Quality Factors For The World Wide Web., Ronan Fitzpatrick Jan 2000

Additional Quality Factors For The World Wide Web., Ronan Fitzpatrick

Conference papers

Web site development is maturing from the enthusiastic experimental practice of early years to a more professional discipline, addressing the needs of Web site visitors and owner organisations. Quality is central to this maturing and it is necessary to have a full understanding of the meaning of quality in the context of the ever-changing Web. This paper identifies five new quality factors for the Web (visibility, credibility, intelligibility, engagibility and differentiation), together with their characteristics and a checklist of enablers, which can be used by specifiers, designers, developers and evaluators to create quality Web sites.


Pid Compensation Of Time Delayed Processes: A Survey, Aidan O'Dwyer Jan 2000

Pid Compensation Of Time Delayed Processes: A Survey, Aidan O'Dwyer

Conference papers

An extensive literature exists on the PID compensation of time delayed processes. It is possible to identify themes that are common to many of the available techniques. The intention of the paper is to provide a framework against which the literature may be viewed.


Convergence Of Parameter And Delay Estimates Using Open Loop Time Domain Gradient Methods, Aidan O'Dwyer, John Ringwood Jan 2000

Convergence Of Parameter And Delay Estimates Using Open Loop Time Domain Gradient Methods, Aidan O'Dwyer, John Ringwood

Conference papers

This paper discusses the estimation of the parameters of a single input, single output (SISO) process, modelled in first order lag plus delay (FOLPD) form, using gradient methods in the open loop time domain. The paper considers the convergence of the process parameters to the model parameters. The convergence of the model delay is discussed first, when the non-delay model and process parameters are identical. The convergence of all of the model parameters is then considered, when all of the process parameters are unknown.


A Summary Of Pi And Pid Controller Tuning Rules For Processes With Time Delay. Part 2: Pid Controller Tuning Rules, Aidan O'Dwyer Jan 2000

A Summary Of Pi And Pid Controller Tuning Rules For Processes With Time Delay. Part 2: Pid Controller Tuning Rules, Aidan O'Dwyer

Conference papers

The ability of proportional integral (PI) and proportional integral derivative (PID) controllers to compensate many practical industrial processes has led to their wide acceptance in industrial applications. The requirement to choose either two or three controller parameters is perhaps most easily done using tuning rules. A summary of tuning rules for the PID control of single input, single output (SISO) processes with time delay is provided in this paper.