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Articles 4231 - 4260 of 4606

Full-Text Articles in Engineering

Bs News Jul 2000

Bs News

Building Services Engineering

No abstract provided.


The Systems Approach To Supply Chain Re-Engineering, Edward Sweeney Jun 2000

The Systems Approach To Supply Chain Re-Engineering, Edward Sweeney

Practitioner Journals

No abstract provided.


Bs News Jun 2000

Bs News

Building Services Engineering

No abstract provided.


Using Raster Sketches For Digital Image Retrieval, James Carswell May 2000

Using Raster Sketches For Digital Image Retrieval, James Carswell

Other resources

This research addresses the problem of content-based image retrieval using queries on image-object shape, completely in the raster domain. It focuses on the particularities of image databases encountered in typical topographic applications and presents the development of an environment for visual information management that enables such queries. The query consists of a user-provided raster sketch of the shape of an imaged object. The objective of the search is to retrieve images that contain an object sufficiently similar to the one specified in the query. The new contribution of this work combines the design of a comprehensive digital image database on-line …


Bs News May 2000

Bs News

Building Services Engineering

No abstract provided.


Bs News Apr 2000

Bs News

Building Services Engineering

No abstract provided.


Bs News Mar 2000

Bs News

Building Services Engineering

No abstract provided.


Bs News Feb 2000

Bs News

Building Services Engineering

No abstract provided.


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 …


Improved Direct Solver For Building Energy Simulation, Michael Crowley, Saleem Hashmi Jan 2000

Improved Direct Solver For Building Energy Simulation, Michael Crowley, Saleem Hashmi

Articles

Finite difference methods, when applied to the differential equations modelling energy flows in buildings, give rise to a system of non-linear difference equations. A frequently used direct solution method involving linearization is analysed and a related method proposed. These and one other connected method are compared using a building related test problem prepared for this purpose. The proposed numerical method is found to produce least error, about 30% less than the commonly used method, and it is recommended for inclusion in building energy simulation software. A fundamental method for estimating the pre conditioning period of a building, arising from the …


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.


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.


The Software Quality Star (Sq-Star), Ronan Fitzpatrick Jan 2000

The Software Quality Star (Sq-Star), Ronan Fitzpatrick

Other resources

Usability is a significant factor in the creation of quality software products which is an important focus of the software engineering syllabus. Usability is also a significant factor in the study of Human-Computer Interaction (HCI). Despite the connection, software quality and the rigours of the software engineering discipline are not used in the teaching of HCI and visa versa. Consequently, students undertaking software engineering courses are not fully exposed to usability issues and HCI students often miss out on the disciplines of software engineering. This paper presents a quality focused conceptual model - the Software Quality Star - which can …


Micro-Raman Study Of Stress Distribution Generated In Silicon During Proximity Rapid Thermal Diffusion, M. Nolan, T. Perova, R. A. Moore, C. J. Moore, Kevin Berwick, H. S. Gamble Jan 2000

Micro-Raman Study Of Stress Distribution Generated In Silicon During Proximity Rapid Thermal Diffusion, M. Nolan, T. Perova, R. A. Moore, C. J. Moore, Kevin Berwick, H. S. Gamble

Articles

proximity rapid thermal diffusion (RTD). A compressive stress was found on the whole silicon wafer after 15 s RTD. After 165 s RTD, the distribution of the stress across the wafer was found to be different: compressive at the edge and tensile at the middle. Thermal stress was relieved in the RTD wafers via slip dislocations. These slip dislocations were observed in the product wafers using optical microscopy. Slip lines propagated from the wafer edge to the wafer centre in eight preferred positions of maximum induced stress. The thermally induced stress and the slip dislocation density increased with time spent …


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 …


Rotary Honing: A Variant Of The Taylor Paint-Scraper Problem, Christopher Hills, H. Moffatt Jan 2000

Rotary Honing: A Variant Of The Taylor Paint-Scraper Problem, Christopher Hills, H. Moffatt

Articles

The three-dimensional Row in a corner of fixed angle α induced by the rotation in its plane of one of the boundaries is considered. A local similarity solution valid in a neighbourhood of the centre of rotation is obtained and the streamlines are shown to be closed curves. The effects of inertia are considered and are shown to be significant in a small neighbourhood of the plane of symmetry of the flow. A simple experiment confirms that the streamlines are indeed nearly closed; their projections on planes normal to the line of intersection of the boundaries are precisely the 'Taylor' …


Synthesis Of Thermally Stable, High Surface Area Anatase–Alumina Mixed Oxides, Suresh Pillai, Hareesh Us, Rajeshkumar S, Mukundan P, Kgk Warrier Jan 2000

Synthesis Of Thermally Stable, High Surface Area Anatase–Alumina Mixed Oxides, Suresh Pillai, Hareesh Us, Rajeshkumar S, Mukundan P, Kgk Warrier

Articles

No abstract provided.


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.


Electroanalysis Using Differential Pulse Methods And Stripping Techniques., Enda Howard Jan 2000

Electroanalysis Using Differential Pulse Methods And Stripping Techniques., Enda Howard

Masters

Application of a differential pulse waveform to a microelectrode or a rotating disk electrode results in a peaked response for amperometric redox reactions. Based on these observations models were proposed and tested for these methods. Simulations of the models were carried out by inputting the relevant equations into Microsoft Excel. The microelectrode study revealed a good correlation between one model and the numerical derivative of the current following a linear sweep potential waveform. Experimentally the derivative can be obtained numerically following a linear sweep. The alternative differential pulse waveform requires more sophisticated equipment and the response can be affected by …


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.


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.


Bs News Jan 2000

Bs News

Building Services Engineering

No abstract provided.


Development Of Cfd Algorithms For Transient And Steady Aerodynamics, Fergal Boyle [Thesis] Dec 1999

Development Of Cfd Algorithms For Transient And Steady Aerodynamics, Fergal Boyle [Thesis]

Other Resources

Research carried out in the United States and in Europe over the last 20 years has led to the development of the advanced propeller, a small-diameter, highly-loaded, multi-bladed, swept, variable-pitch propeller, that can achieve potential fuel savings of 30% over an equivalent technology turbofan engine at competitive speed and altitudes.

In this work an implicit finite-volume algorithm is developed for predicting the transient flow around an advanced propeller under asymmetric inflow conditions. The development of the unsteady propeller algorithm evolves from a family of methods for progressively more complex applications. In total six algorithms are developed: three steady and three …


Bs News Dec 1999

Bs News

Building Services Engineering

No abstract provided.


Bs News Nov 1999

Bs News

Building Services Engineering

No abstract provided.


Bs News Oct 1999

Bs News

Building Services Engineering

No abstract provided.


Bs News Sep 1999

Bs News

Building Services Engineering

No abstract provided.