Digital Commons Network^™

Square Planar Monopole Antenna, Max Ammann

Conference papers

A planar monopole may be realised by replacing the wire element of a conventional monopole with a planar element. In this case, the planar element which is square, is located above a groundplane and fed using an SMA connector as illustrated. The square monopole has a simple geometry and a smaller bandwidth compared to the circular-disc monopole. However, it is still a broadband antenna with a typical impedance bandwidth of 75 % at S band. This broadband antenna shows a constant radiation pattern over the impedance bandwidth. A simple formula for the frequency corresponding to the lower edge of the …

Annual Report 1 September 1998 - 31 August, 1999, Dublin Institute Of Technology

DIT Annual Reports

No abstract provided.

1999 - 2000 : Part - Time Courses, Dublin Institute Of Technology

DIT Publications

Book containing map of DIT main locations, student information, student regulations, key contacts and full listing of part-time programmes on offer at DIT 1999

A Feature Library Approach To On-Line Image Querying And Retrieval For Topographic Applications, James Carswell

Conference papers

In this paper we address the problem of content-based image retrieval using queries on shape and topology. We focus on the particularities of image databases encountered in typical topographic applications, and present the development of a spatial data management system that enables such queries. The query uses as input user-provided sketches of the shape and spatial configuration of the object (or objects) which should appear in the images to be retrieved. The objective of the search is to retrieve images that contain a configuration of objects sufficiently similar to the one specified in the query. Our novel approach introduces the …

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

Conference papers

A summary of tuning rules for the PID control of single input, single output (SISO) processes with time delay, modeled in stable first order lag plus time delay (FOLPD) form, is provided in this part of the paper.

A Socio-Economic Analysis Of Student Population In Third Level Education., Pat Mcgarthy, Dermot Duffy

Irish Journal of Applied Social Studies

The pursuit of knowledge and the availability of an educational qualification has always been an aspiration of most citizens in developed and less developed economies worldwide. In modern Ireland, the educational system has prided itself as one of the more advanced models vis-a-vis student quality and educational participation structured and quality educational population. Eighty per cent of Irish school children now sit their Leaving Certificate, and there has been a fivefold increase in third level enrolments over the last thirty years. Despite such admirable statistics, large levels of socio-economic depravation still exist in our third level education, so much so …

The Appearance Of Ferrielectric Phases In Confined Liquid Crystal Studied By Photon Correlation Spectroscopy, Yuri Panarin, Fouad M. Aliev, Charles Rosenblatt

Articles

The influence of confinement on the dynamic properties and appearance of ferrielectric phases has been investigated by dynamic light scattering, performed in the bulk AFLC as well as confined in 200 8, and 2000 8, cylindrical pores. The analysis of the experimental results shows that the ferrielectric phases are not formed in 200 A pores, while they appear in 2000 8, pores as well as in bulk.

Application Of Pvd Coatings To Enhance The Wear Life Of Needles Used In The Textile Industry, Neil Donnelly

Masters

Needles are used in the textile industry for weaving. In high volume textile production a problem is wear of the needle eyelet as the threat is pulled through. This wear results in a cost to the textile manufacturer both in needle replacement, but in many cases more importantly, lost production during needle substitution The objective of this study was to examine the potential of wear resistant coatings deposited using the magnetron sputtering technique to increase the life-time of textile needles. Four coatings were evaluated, titanium nitride, titanium carbonitride, titanium diamond-like carbon and a novel coating titanium nitride/molybdenum disulphide. These coatings …

Investigation Of The Thickness Mode In Surface Stabilized Ferroelectric Liquid Crystal Cells, O.E. Kalinovskaya, J.K. Vij, Yu. V. Tretyakov, Yuri Panarin, Yu. P. Kalmykov

Articles

Dielectric properties of surface stabilized ferroelectric liquid crystal (SSFLC) cells have been investigated both experimentally and theoretically. The thickness mode is found to consist of two relaxation processes. A decomposition of an analytical solution of the complex dielectric permittivitye(v) in terms ofthese processesis given. Theexperimental results showagreement with theory and lead to the conclusion that the thickness mode can be separated into two processes. It has been found that the ratio of the dielectric strengths for the two processes depends on the cell thickness, and that the ratio of their frequencies is approximately equal to 10. The lower frequency process …

The Dynamic Properties Of 5cb Filled With Aerosil Particles Investigated By Pcs, F.M. Aliev, M. Kreuzer, Yuri Panarin

Articles

Nematic liquid crystal filled with Aerosil particles, a prospective composite material for optoelectronic application, has been investigated by static light scattering and Photon Correlation Spectroscopy (PCS). The Aerosil particles in filled nematic liquid crystals (FN) form a network structure with LC domains about 2500 Å in size with a random distribution of the director orientation of each domain. We found that the properties of 5CB are considerably affected by the network. The N-I phase transition in filled 5CB was found to be smeared out and depressed. PCS experiments show that two new relaxation processes appear in filled 5CB in addition …

The Dynamic Properties Of Confined Antiferroelectric Liquid Crystal Investigated By Photon Correlation Spectroscopy, Yuri Panarin, C. Rosenblatr, F.M. Aliev

Articles

Dynamic light scattering was used to examine ferrielectric liquid crystalline phases in porous media. Whereas in larger pores (200 Å) ferrielectric phases were observed, they were not found in the smallest pores (200 Å). Additionally, the temperatures of SmC - SmA phase transition were found to be suppressed in the pores relative to bulk, while SmCA - SmCγ phase transition is not affected by the confinement. These observations have been explained by the structural aspects of antiferroelectric liquid crystalline materials in a confined geometry and show the importance of long range electrostatic interaction for existence of ferrielectric phases.

Robust Controller Design For Time Delay Systems Using H-Infinity Techniques, Susan Carr, Aidan O'Dwyer

Conference papers

Using H-infinity control, the design problem is formulated in terms of user defined weighting polynomials on the process closed-loop sensitivity functions to achieve desired closed-loop performance and robust stability in the presence of process modelling error. In this paper stability conditions , in terms of the process sensitivity functions, are derived for processes containing a pure time delay for the following three design scenarios i) the time delay is neglected in the control design and is considered as part of the unmodelled process dynamics ii) A Pade approximation of the delay is included in the controller design and the effect …

A Classification Of Techniques For The Compensation Of Time Delayed Processes. Part 1: Parameter Optimised Controllers, Aidan O'Dwyer, John Ringwood

Conference papers

An extensive literature exists on the compensation of time delayed processes. It is possible to identify themes that are common to many of the available techniques. The intention of the two parts of this paper is to provide a framework against which the literature may be viewed; Part 1 of the paper considers the use of parameter optimised controllers for the compensation problem, with Part 2 of the paper considering the use of structurally optimised compensators. Conclusions are drawn at the end of Part 2.

A Classification Of Techniques For The Compensation Of Time Delayed Processes. Part 2: Structurally Optimised Controllers, Aidan O'Dwyer, John Ringwood

Conference papers

Following on from Part 1, Part 2 of the paper considers the use of structurally optimised controllers to compensate time delayed processes.

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

Conference papers

In this paper, we present three different approaches to fit the experimental data of a process with time delay in the time domain. Two of the proposed methods are based on the step response, and the third is based on the pulse response. The effectiveness of these techniques is verified by simulation results and by real-time experimental data. Only first order lag plus time delay models are considered in this paper.

Annual Report 1 September 1998 - 31 August, 1999, Dublin Institute Of Technology

DIT Annual Reports

No abstract provided.

Management Of Change In The Irish Construction Industry, Louis Gunnigan

Masters

Ireland is changing and this change is nowhere more apparent than in the rapidly growing construction industry. The industry is being forced to change at an unprecedented pace. This thesis sets out to develop a framework on which construction organisations can approach and manage change.

It examines the issues that will cause change, reviews the available literature to find how change can be managed and controlled, and develops a model for guiding change programmes in the construction industry. The model is tested against three case studies, the first two of which are concerned with finding increases in efficiency and demonstrating …

Using Xml To Network Distributed Analytical Instruments: Back To The Future?, Benjamin Jung, Damon Berry, Jane Grimson

Conference Papers

There has been a paradigm shift in medical informatics standards in recent years from the message-oriented approach to a more distributed systems approach. However, despite all the early promise of distributed applications, they haven't been widely adopted in the health domain for various reasons. As a result, despite an increasing need for a standardised distributed solution for analytical laboratory instruments, many implementers of instrument interfaces are still using proprietary serial interfaces which do not support distribution. The emergence of the eXtended Markup Language (XML) specification in 1998 revived the fortunes of the messaged oriented methodology. This paper presents a partial …

A Process For Appraising Commerical Usability Evaluation Methods., Ronan Fitzpatrick, Alan Dix

Conference papers

Recent international quality standards and European Community legislation have identified new software quality factors. These new factors include suitability, installability and adaptability. Other quality factors need to be reviewed in the light of these developments. This has impacted on established commercial usability evaluation methods to the extent that it is appropriate to ask if these evaluation methods comply with the new standards and legislation. In order to answer this question the commercial evaluation methods need to be appraised (meta-evaluation) using a suitable method appraisal process. This paper describes such an appraisal process which specifically addresses the many considerations raised by …

Bs News

Building Services Engineering

No abstract provided.

Bs News

Building Services Engineering

No abstract provided.

The Dit Examiner : The Newspaper Of The Dublin Institute Of Technology Students' Union, November - December, 1998, Dit Students' Union

DIT Student Union

The DIT Examiner : the Newspaper of the Dublin Institute of Technology Students' Union.

Bs News

Building Services Engineering

No abstract provided.

The Dit Examiner : The Newspaper Of The Dublin Institute Of Technology Students' Union, October, 1998, Dit Students' Union

DIT Student Union

The DIT Examiner : the Newspaper of the Dublin Institute of Technology Students' Union.

Bs News

Building Services Engineering

No abstract provided.

A Transverse Examination Of Occupational Stress Among A Cross Disciplinary Population Of Irish Construction Professionals, Myles Keaveney

Conference papers

The effect of occupational stress upon managerial and professional staff is increasingly being realised and studied. This paper presents the findings of a recent postal survey of 94 Irish Construction Professionals to evaluate the incidence and causes of occupational stress. 70% of the re spondents considered that their work was having an adverse effect on their family and 55% believed that it was affecting their health. 40% have considered early retirement because of severe occupational stress, which appears to be a growing blight on Construction Professionals. The research found, not unexpectedly, that Site Managers had the most stressful roles, followed …

1998 - 1999 : Student Information, Dublin Institute Of Technology

DIT Publications

Handbook for new students covering all aspects of college life.

Institute facilities, student services, and student regulations.

Foreward by Dr. Brendan Goldsmith, President.

Bs News

Building Services Engineering

No abstract provided.

Digital Image Retrieval Using Shape-Based Queries, James Carswell

Conference papers

In this paper we present the development of a spatial data management system utilizing sketch-based queries for the content-based retrieval of digital images from topographic databases. We discuss our overall strategy and associated algorithmic and implementational aspects, and present the associated database design issues. The query tools devised in this research are employing user-provided sketches of the shape and spatial configuration of the object(s) which should appear in the images to be retrieved. Our strategy is scale-independent. It is inspired by least-squares matching (lsm), and represents an extension of lsm to function with a variety of raster representations. The results …

Bs News

Building Services Engineering

No abstract provided.