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2007

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Articles 4051 - 4080 of 4444

Full-Text Articles in Engineering

Inset-Fed Mircrostrip Patch Antenna With Integrated Polycrystalline Photovoltaic Solar Cell, S. Shynu, Maria Roo Ons, Max Ammann, Sarah Gallagher, Brian Norton Jan 2007

Inset-Fed Mircrostrip Patch Antenna With Integrated Polycrystalline Photovoltaic Solar Cell, S. Shynu, Maria Roo Ons, Max Ammann, Sarah Gallagher, Brian Norton

Conference papers

A novel method of integrating microstrip patch antennas and polycrystalline silicon solar cells for application in autonomous communication systems is presented. The DC and RF functions are intimately linked, by using the silver DC bus bars of the solar cell as the ground plane of the microstrip patch. The performance of the solar antenna is compared with standard microstrip patch. Detailed studies of the effect of the solar cell on the microstrip antenna are then carried out. The effects of solar cell integration, DC loading and variation in incident photon intensity of the silicon layer on the performance of the …


High Quality Millimeter Wave Generation Via Stimulated Brillouin Scattering, Marcus Junker, Thomas Schneider, Kai-Uwe Lauterbach, Ronny Henker, Max Ammann, Andreas Schwarzbacher Jan 2007

High Quality Millimeter Wave Generation Via Stimulated Brillouin Scattering, Marcus Junker, Thomas Schneider, Kai-Uwe Lauterbach, Ronny Henker, Max Ammann, Andreas Schwarzbacher

Conference papers

A new and simple method for the generation and modulation of Millimeter waves is presented. Based on frequency upconversion via Stimulated Brillouin Scattering, it is very flexible in its output frequency and modulation bandwidth.


Printed Band-Rejection Uwb Antenna With H-Shaped Slot, Xiulong Bao, Max Ammann Jan 2007

Printed Band-Rejection Uwb Antenna With H-Shaped Slot, Xiulong Bao, Max Ammann

Conference papers

The development of the high data rate wireless communication systems, has placed significant demands on antenna designers, in particular, the requirement for smaller elements with broader bandwidths. In this paper, a novel UWB antenna with notch-band frequency is studied. Effects of the various parameters for antenna performances are also discussed. An optimized compact UWB antenna with notch-frequency function is fabricated and experimentally examined. The measured results show the proposed UWB antenna can achieve a return loss greater than 10 db over an ultrawide bandwidth, of 9.8 GHz, from 2.97 GHz to 12.77 GHz with a tunable notch-frequency band of 5.15 …


Some Techniques To Improve Small Groundplane Printed Monopole Performance, Max Ammann, Matthias John Jan 2007

Some Techniques To Improve Small Groundplane Printed Monopole Performance, Max Ammann, Matthias John

Conference papers

Printed planar monopole antennas are enjoying considerable popularity and publicity to their low-profile, wide bandwidth, quasi-omnidirectional radiation characteristics and their ease of integratability into devices. The impedance bandwidth and radiation properties of a strip monopole have been shown to be heavily dependent on groundplane size. The groundplane (GP) is of primary importance and when miniaturised, the antenna properties change significantly. Techniques to improve the performance of printed antennas on small groundplanes are presented.


Slow And Fast-Light In Optical Fibers: An Overview, Ronny Henker, Thomas Schneider, Kai-Uwe Lauterbach, Markus Junker, Max Ammann, Andreas Schwarzbacher Jan 2007

Slow And Fast-Light In Optical Fibers: An Overview, Ronny Henker, Thomas Schneider, Kai-Uwe Lauterbach, Markus Junker, Max Ammann, Andreas Schwarzbacher

Conference papers

Slow- and fast-light is the control of the velocity of light in a medium by light. As a fascinating new field in physics there is a fundamental interest on this effect on the one side, but on the other side there exist a lot of practical applications for telecommunication and information systems. Among these are optical signal processing, the radio frequency-photonics, nonlinear optics and spectroscopy in time domain. Furthermore, the slow- and fast-light effect can be seen as a key technology for optical delay lines, buffers, equalizers and synchronizers in packed switched networks. To realize the effect there are different …


Spline Based Geometry For Printed Uwb Antenna Design, Matthias John, Max Ammann Jan 2007

Spline Based Geometry For Printed Uwb Antenna Design, Matthias John, Max Ammann

Conference papers

This paper presents a geometry for ultra-wideband (UWB) antennas which is based on quadratic Bezier spline curves. A genetic algorithm (GA) is used to optimise the geometry. The search space for the GA is minimised in order to improve the performance and computational efficiency of the algorithm. The optimised antenna covers the entire UWB bandwidth.


Identification Of A Time-Delayed Process Model Using An Overparameterisation Method, John Roe, Ruiyao Gao, Aidan O'Dwyer Jan 2007

Identification Of A Time-Delayed Process Model Using An Overparameterisation Method, John Roe, Ruiyao Gao, Aidan O'Dwyer

Conference papers

An extensive literature exists on the estimation of the model parameters of time-delayed processes. This paper briefly reviews the main overparameterisation methods for the Single-Input, Single Output (SISO) and Multi-Input, Multi-Output (MIMO) model parameter (and time delay) estimation problem. Subsequently, two algorithms, and their modifications, are discussed, and their performances are assessed in simulation. Results indicate that both the algorithms can suitably identify the model parameters, including the time delay. The third author has taught the method successfully to students taking advanced level control courses at DIT for a number of years; these experiences will be briefly reported. The paper …


Using Controller Tuning Formulae To Improve Performance, Aidan O'Dwyer Jan 2007

Using Controller Tuning Formulae To Improve Performance, Aidan O'Dwyer

Conference papers

The proportional integral derivative (PID) controller is the most dominant form of automatic controller in industrial use today. With this device, it is necessary to adjust the controller parameters according to the nature of the process. Thus, for effective control of a HVDC system, for example, specific values need to be chosen for the P, I and D parameters, which will be different for the values required to control, for example, an induction motor drive. This tailoring of controller to process is known as controller tuning. Controller tuning is easily and effectively performed using tuning rules (i.e. formulae for controller …


Biotechnology, Life Sciences And Control Engineering:Some Synthesis Issues, Aidan O'Dwyer Jan 2007

Biotechnology, Life Sciences And Control Engineering:Some Synthesis Issues, Aidan O'Dwyer

Conference papers

The synthesis of biotechnology, life sciences and control engineering is receiving increasing interest. The purpose of this contribution (and the associated poster) is to raise awareness of some of this synthesis work.


Pure Non-Blocking Lc Based Matrix Optical Switch For All-Optical Fibre Networks, Yuri Panarin, V. Alex Jan 2007

Pure Non-Blocking Lc Based Matrix Optical Switch For All-Optical Fibre Networks, Yuri Panarin, V. Alex

Articles

New pure non-blocking matrix optical switch scheme for fiber networks is presented. The optical switch is based on conventional LCD technology, where the each pixel controls the polarization state of the light beam. The suggested switch offers several advantages over the conventional cross-point architecture such as: cost; complexity; size; adjustment; and optical performance


Slow Flow Between Concentric Cones, O. Hall, C. P. Hills, A. D. Gilbert Jan 2007

Slow Flow Between Concentric Cones, O. Hall, C. P. Hills, A. D. Gilbert

Articles

This paper considers the low-Reynolds-number flow of an incompressible fluid contained in the gap between two coaxial cones with coincident apices and bounded by a spherical lid. The two cones and the lid are allowed to rotate independently about their common axis, generating a swirling motion. The swirl induces a secondary, meridional circulation through inertial effects. For specific configurations complex eigenmodes representing an infinite sequence of eddies, analogous to those found in two-dimensional corner flows and some three-dimensional geometries, form a component of this secondary circulation. When the cones rotate these eigenmodes, arising from the geometry, compete with the forced …


Krylov Subspaces From Bilinear Representations Of Nonlinear Systems, Marissa Condon, Rossen Ivanov Jan 2007

Krylov Subspaces From Bilinear Representations Of Nonlinear Systems, Marissa Condon, Rossen Ivanov

Articles

For efficient simulation of state-of-the-art dynamical systems as arise in all aspects of engineering, the development of reduced-order models is of paramount importance. While linear reduction techniques have received considerable study, increasingly nonlinear model reduction is becoming a significant field of interest. From a circuits and systems viewpoint, systems involving micromachined devices or systems involving mixed technologies necessitate the development of reduced-order nonlinear models. From a control systems viewpoint, the design of controllers for nonlinear systems is greatly facilitated by nonlinear model reduction strategies. To this end, the paper proposes two novel model-reduction strategies for nonlinear systems. The first involves …


A Framework For The Introduction Of Organisational Learning Using Web 2.0 Applications, Joseph M. Reynolds Jan 2007

A Framework For The Introduction Of Organisational Learning Using Web 2.0 Applications, Joseph M. Reynolds

Dissertations

We are now becoming more and more dependent on web technologies in our personal lives for our communication, information and entertainment needs. But what about using these skills and technologies for our business lives, could they transform the business world in the same way they have transformed our personal world? The purpose of this research was to investigate whether the latest web applications could be successfully implemented into an organisation who wished to transform itself into a modern and flexible organisation. This research was primarily focused on introducing organisational learning into the business through the use of new technology and …


Using Gis To Assess Ireland's Knowledge Economy And Its Readiness For Knowledge Based Activity, Niall Mcguinness Jan 2007

Using Gis To Assess Ireland's Knowledge Economy And Its Readiness For Knowledge Based Activity, Niall Mcguinness

Dissertations

The attractiveness of emerging low wages economics to primary industries such as manufacturing and production is forcing many western economies to transition to knowledge economies. In the absence of many forms of primary industry lost to low wage economies, the European Union and its members are fast realising the importance of attracting knowledge based enterprise in order to maintain Europe’s economic climate. Ireland too has a stated aim to become a knowledge economy by the year 2010. This can be achieved by investing in higher education and attracting knowledge industry to the country. Ireland has made some progress to achieving …


Information Architecture For Irish Grocery Retailers Using Business Intelligence Tools, Patrick Doran Jan 2007

Information Architecture For Irish Grocery Retailers Using Business Intelligence Tools, Patrick Doran

Dissertations

Business Intelligence (BI) systems have a pivotal role to play in assisting retail management in the Irish grocery retail sector. The emergence of super chain stores and the increasing competition within this sector only increases their need for an effective and reliable Business Intelligence (BI) system. However, despite this growing need Business Intelligence (BI) systems as they are currently deployed and used are not supplying the various levels of management with the necessary information they require to make effective retail management decisions. The information and reports received from Business Intelligence (BI) systems lack structure, are missing important pieces of information …


Investigating Text Message Classification Using Case-Based Reasoning, Matt Healy Jan 2007

Investigating Text Message Classification Using Case-Based Reasoning, Matt Healy

Masters

Text classification is the categorization of text into a predefined set of categories. Text classification is becoming increasingly important given the large volume of text stored electronically e.g. email, digital libraries and the World Wide Web (WWW). These documents represent a massive amount of information that can be accessed easily. To gain benefit from using this information requires organisation. One way of organising it automatically is to use text classification. A number of well known machine learning techniques have been used in text classification including Naïve Bayes, Support Vector Machines and Decision Trees, and the less commonly used are k-Nearest …


Physiochemical Indicators Of Single Walled Carbon Nanotube Toxicity, Alan Casey Jan 2007

Physiochemical Indicators Of Single Walled Carbon Nanotube Toxicity, Alan Casey

Doctoral

Numerous toxicity studies have been conducted to date both in vivo and in vitro on refined and raw Single Walled Carbon Nanotubes (SWCNT). Differences in SWCNT toxicity and biocompatibility have been observed between these studies, and whilst these discrepancies have been attributed to factors such as varying percentages of remnant catalytic particles, differences in dispersion methods etc. the mechanisms underlying these inconsistencies have not been investigated. This study used standard spectroscopic and cellular techniques to elucidate the origins of these inconsistencies and also to estimate the validity of toxicological data evaluated form standard cytotoxic endpoints. Spectroscopic studies were conducted in …


Key Signature Estimation, Matt Cranitch, Derry Fitzgerald, Matthew Hart Jan 2007

Key Signature Estimation, Matt Cranitch, Derry Fitzgerald, Matthew Hart

Conference papers

The problem of automatic key signature detection has been the focus of much research in recent years. Previous methods of key estimation have focused on chromagrams and key profiling techniques. This paper presents a remarkably simple but effective method of estimating key signature from musical recordings. The algorithm introduces the "keyogram", a concept resembling the chromagram, and is aimed for use on traditional Irish music. The keyogram is a measure of the likelihood of each possible major key signature based on a masked scoring system.


Time Signature Detection By Using A Multi Resolution Audio Similarity Matrix, Mikel Gainza, Eugene Coyle Jan 2007

Time Signature Detection By Using A Multi Resolution Audio Similarity Matrix, Mikel Gainza, Eugene Coyle

Conference papers

A method that estimates the time signature of a piece of music is presented. The approach exploits the repetitative structure of most music, where the same musical bar is repeated in different parts of a piece. The method utilised a multi-resolution audio similarity matrix approach, which allows comparisons between longer audio segments (bars) by combining comparisons of shorter segments (fraction of a note). The time signature method only depends on musical structure, and does not depend on the presence of percussive instruments or strong musical accents.


Citax: Defining Xml Standards For Data Exchange In The Construction Industry Supply Chain, Alan V. Hore, Roger West Jan 2007

Citax: Defining Xml Standards For Data Exchange In The Construction Industry Supply Chain, Alan V. Hore, Roger West

Conference papers

The current methods of ordering, delivering and invoicing of products in the construction industry is enormously inefficient, with vast quantities of paperwork, duplication of effort, scanning, re-keying and resolving mismatches between invoices, delivery dockets and purchase orders. The purpose of this paper is to introduce the Construction IT Alliance eXchange (CITAX) project and, in particular, to outline the work carried out-to-date by a special interest group within the project. They are seeking to define a universal set of eXtensible Mark-Up Language (XML) message standards that will allow suppliers and contractors to exchange information with each other in supply chain activity. …


Medical Rehabilitation Robotics, David Kennedy, Philip Deering, James Conlon Jan 2007

Medical Rehabilitation Robotics, David Kennedy, Philip Deering, James Conlon

Conference Papers

Robotic Rehabilitation is a novel field of bio engineering combining precise mechanical design with control technology through the interaction of Medical and Engineering professionals to produce a new tool in medical rehabilitation. Paralysis is one of the common symptoms of a stroke sufferer; a medical condition causing weakness in one side of the body. It is treatable with a course of physiotherapy and Interactive Robotics can greatly accelerate this recovery. Although Robotic Rehabilitation is a relatively new technology its benefits are well recognized. The objective of this research work was to develop an interactive robot for the medical rehabilitation of …


Real-Time Detection Of Grip Length Deviation For Fastening Operations: A Mahalanobis-Taguchi System (Mts) Based Approach, Deepak Mohan Jan 2007

Real-Time Detection Of Grip Length Deviation For Fastening Operations: A Mahalanobis-Taguchi System (Mts) Based Approach, Deepak Mohan

Masters Theses

"Hand-held fastening tools are extensively used in manufacturing, especially in aerospace industry. Typically, the process is monitored by the operator and joints are visually inspected after the process is completed. When complex products, such as an aircraft, are considered, fastening process and its inspection can be very time consuming. In addition, no inspection data is typically collected during the process unless a major problem is encountered. Real-time monitoring and verification of the fastening process of joint quality are two important advancements to reduce the manufacturing lead time while ensuring safety and quality"--Abstract, page iv.


Efficacy Of Removal Of Ccl Viruses Under Enhanced Coagulation Conditions, Morteza Abbaszadegan, Brooke Mayer, Hodon Ryu, Nena Nwachuku Jan 2007

Efficacy Of Removal Of Ccl Viruses Under Enhanced Coagulation Conditions, Morteza Abbaszadegan, Brooke Mayer, Hodon Ryu, Nena Nwachuku

Civil and Environmental Engineering Faculty Research and Publications

The focus of coagulation as a water treatment process is shifting to accommodate recent regulatory additions that strive to balance the risks between microbial and chemical contamination of drinking water. In this work, enhanced coagulation using increased ferric chloride dose and/or pH adjustment was evaluated for removal efficacy of viruses on the United States Environmental Protection Agency (USEPA) Contaminant Candidate List (CCL), their surrogates, and dissolved organic carbon (DOC). Jar tests demonstrated that optimal DOC removal was achieved using 40 mg/L FeCl3 at a pH between 5 and 6. Under these conditions, bench-scale testing resulted in a maximum removal …


The Effect Of The Size Of Pinning Centres On The Critical Current Density In High-Temperature Superconductors, Salama Bakhit Sowaidan Al-Neaimi Jan 2007

The Effect Of The Size Of Pinning Centres On The Critical Current Density In High-Temperature Superconductors, Salama Bakhit Sowaidan Al-Neaimi

Theses

Superconductor materials that have no resistance to the flow of electricity are one of the last great frontiers of scientific discovery.

Superconductivity in these materials occurs particularly in the copper-oxide (CuO2) planes. However, since these materials are type-II superconductors, magnetic fields can penetrate these materials in quantized amounts of flux called vortices without completely destroying superconductivity, but producing some resistance, due to vortex motion. In order to overcome the resistance problem, vortices must be pinned to prevent their motion and hence eliminate the resistance.

In this work study we have performed extensive numerical simulations to study the effect …


Swarms In Biology And Engineering, Kevin M. Passino Jan 2007

Swarms In Biology And Engineering, Kevin M. Passino

Turkish Journal of Electrical Engineering and Computer Sciences

No abstract provided.


A New Relaying Algorithm To Detect Loss Of Excitation Of Synchronous Generators, Ömer Usta, M. H. Musa, M. Bayrak, M.A. Redfern Jan 2007

A New Relaying Algorithm To Detect Loss Of Excitation Of Synchronous Generators, Ömer Usta, M. H. Musa, M. Bayrak, M.A. Redfern

Turkish Journal of Electrical Engineering and Computer Sciences

A new digital relaying algorithm is introduced for the protection of synchronous generators against loss of excitation conditions. The new algorithm is based on measuring of the 3-phase reactive power output of the machines, and monitors the direction and magnitude of leading reactive power at the generator terminal. The protection algorithm is designed such that it can provide reliable protection against loss of field conditions and remains stable during recoverable power system swing conditions. While the new relay produces a trip signal for partial loss of field conditions causing the machine to lose its stability, it remains stable for the …


Reinforcement-Learning Based Output-Feedback Controller For Nonlinear Discrete-Time System With Application To Spark Ignition Engines Operating Lean And Egr, Peter Shih Jan 2007

Reinforcement-Learning Based Output-Feedback Controller For Nonlinear Discrete-Time System With Application To Spark Ignition Engines Operating Lean And Egr, Peter Shih

Masters Theses

"A spark ignition (SI) engine can be described by non-strict feedback nonlinear discrete-time system with the output dependent upon on the states in a nonlinear manner. The controller developed in this thesis utilizes the inherent universal approximation property of neural networks (NN) to simplify the design process and solve the non-causality problem inherent with traditional designs. It also exploits a long-term performance index called the strategic utility function to minimize and assist in updating of the NN weights; therefore, an optimal controller can be realized. Finally, through Lyapunov equations, the controller guarantees stability"--Abstract, page iv.


Empirical Investigation Of Enhanced Air Fins, Stephen John Dale Rucker Jan 2007

Empirical Investigation Of Enhanced Air Fins, Stephen John Dale Rucker

Masters Theses

"Enhanced convective heat transfer surfaces have been a subject of interest for quite some time. Many different methods have been used to increase the amount of heat transfered from a surface. However, nearly all surface enhancement methods come with a price, frictional losses. This thesis studies the use of enhanced convective heat transfer surfaces on air fins in the laminar, transitional, and turbulent flow regimes with emphasis on the transitional regime. A major goal of this thesis is to further the understanding of the influence of an enhanced wall geometry on the transition from laminar to turbulent flow. Causing the …


Security Analysis Of A Cyber-Physical System, Han Tang Jan 2007

Security Analysis Of A Cyber-Physical System, Han Tang

Masters Theses

"Cyber-Physical Systems (CPSs) are an integration of computing and physical processes. Information flow is an inherent property of CPSs and is of particular interest at their cyber-physical boundaries. This thesis focuses on discovering information flow properties and proposes a process to model the information flow in CPSs. A Cooperating FACTS Power System serves as a tangible example to illustrate modeling information flow using the proposed process. The proposed process can be used to model the information flow security, help analyze current information flow security requirements, and aid in the design of further security policies in CPS"--Abstract, page iii.


Application Of Hybrid Arq To Controller Area Networks, Krishna Chaitanya Emani Jan 2007

Application Of Hybrid Arq To Controller Area Networks, Krishna Chaitanya Emani

Masters Theses

"This thesis proposes two types of Hybrid Automatic Repeat reQuest (HARQ) schemes for the Controller Area Network (CAN) to combat Electro-Magnetic Interference (EMI) and improve network efficiency. The proposed HARQ schemes encode the original CAN data frames by a Reed-Solomon (R-S) code so that burst errors due to EMI may be corrected at the receive nodes. Therefore, the probability of error frames is reduced, thereby reducing the probability of retransmission. Hence, the network efficiency of the system is improved"--Abstract, page iii.