Engineering Commons^™

High Rate Space Time Code With Linear Decoding Complexity For Multiple Transmitting Antennas, Amir Laufer

Dissertations

The multipath nature of the wireless channel, results in a superposition of the signals of each path at the receiver. This can lead to either constructive or destructive interference. Strong destructive interference is frequently referred to as deep fade and may result in temporary failure of communication due to the severe drop in the channel's signal-to-noise ratio (SNR). To avoid this situation, signal diversity might be introduced. When having more than one antenna at the transmitter and / or receiver, forming a Multiple-Input Multiple-Output (MIMO) channel, spatial diversity can be employed to overcome the fading problem. Space time block codes …

Single And Multiphase Mixing In Partially Filled Stirred Vessels, Shilan Motamedvaziri

Dissertations

In many industrial applications, mixing vessels have a liquid height-to-tank diameter ratio, H/T, equal to, or larger than 1. However, there are many instances where this ratio is lower than 1, as in all those cases in which the vessel is either emptied or filled. Even when H/T<1, sufficient agitation must still be provided in order to attain the desired process objectives. When the impeller submergence is reduced as a result of lowering the liquid level, the fluid dynamics of even a single-phase stirred liquid can become quite complex, with different regimes possibly existing depending on the geometric characteristics of the system (such as impeller clearance, liquid height, or liquid submergence above the impeller). The objectives of this work were to study in detail the hydrodynamic changes that occur when H/T is decreased, and to determine the minimum liquid levels and the critical impeller submergence for different impeller off-bottom distances, impeller diameters and agitation speeds where adequate mixing process can still be achieved, both in a single liquid phase and in solid-liquid suspensions.

Flat-bottomed, baffled vessels (5L, 12L, 20L and 170L) equipped with a single disk turbine (DT) of four different sizes placed at five different impeller off-bottom clearances were used here to study the system's hydrodynamics and related mixing phenomena. A number of experimental tools were used to analyze the systems under investigation, including: …

Influence Of Defects And Impurities On Solar Cell Performance, Vinay Budhraja

Dissertations

Multicrystalline silicon (mc-Si) solar cells exhibit high impurity content and higher density of crystal defects such as grain boundaries, dislocations, stacking faults and impurity precipitates. Even though the effect of dislocations on mc-Si solar cell performance has been studied, a severe lack of understanding of the quantitative effects of dislocations on cell parameters still exists. Some correlation has been reported under the assumption of a uniform distribution of dislocation density and a negligible effect of front and back surface recombination velocity. This assumption can cause a significant error as the current mc-Si technology provides good surface passivation by SiN:H and …

Wireless Sensor Network For Health Monitoring, Jin Soo Choi

Dissertations

Wireless Sensor Network (WSN) is becoming a significant enabling technology for a wide variety of applications. Recent advances in WSN have facilitated the realization of pervasive health monitoring for both homecare and hospital environments. Current technological advances in sensors, power-efficient integrated circuits, and wireless communication have allowed the development of miniature, lightweight, low-cost, and smart physiological sensor nodes. These nodes are capable of sensing, processing, and communicating one or more vital signs. Furthermore, they can be used in wireless personal area networks (WPANs) or wireless body sensor networks (WBSNs) for health monitoring. Many studies were performed and/or are under way …

Analysis Of A Composite Dielectric-Ferrite Loaded Resonator Using The Transmission Line Model With Application To A Tunable Dual Mode Bandpass Filter, Charlotte Blair

Dissertations

A magnetically tuned filter is presented in this dissertation. Filter tuning of a dielectric ceramic resonator is accomplished using by using two oppositely biased ferrites. Specifically, a change in the applied magnetic field is used to alter the permeability of the ferrite so as to achieve maximum tuning range. Through electromagnetic (EM) simulations and laboratory experiments, tuning of the filter passband by 20 MHz is demonstrated.

This investigation focuses on the design of a bandpass resonator using a combination of dielectric-ferrite material layers. An initial simplification of the geometry of the structure is used as the basis for a program …

Trust Management Schemes For Peer-To-Peer Networks, Lin Cai

Dissertations

Peer-to-peer (P2P) networking enables users with similar interests to exchange, or obtain files. This network model has been proven popular to exchange music, pictures, or software applications. These files are saved, and most likely executed, at the downloading host. At the expense of this mechanism, worms, viruses, and malware find an open front door to the downloading host and gives them a convenient environment for successful proliferation throughout the network. Although virus detection software is currently available, this countermeasure works in a reactive fashion, and in most times, in an isolated manner. A trust management scheme is considered to contain …

Hot-Melt Mixing Of Partially Miscible Active Pharmaceutical Ingredient-Polymer Mixtures, Min Yang

Dissertations

Solid dispersion/solution processes for producing pharmaceutical oral dosages such as hot-met extrusion (HME) have received increasing attention by industry and academe because they can enhance drugs’ solubility and even bioavailability to a great extent by converting drugs from crystalline to amorphous form. HME can be carried out at two process temperature regimes: one where T_process > T_m of the drug and the T_g of the polymer (or the T_m for the case of semi-crystalline polymers); the other at T_m > T_process > T_g (T_m for the case of semi-crystalline polymer). Processing below the drug’s …

Micromechanical Study Of Two-Phase Flow During Air Sparging, Shengyan Gao

Dissertations

Air sparging (AS) is an in-situ soil/groundwater remediation technology, which involves the injection of pressurized air/oxygen through an air sparging well below the region of contamination. The efficiency of the in-situ sparging system is mainly controlled by the extent of contact between injected air and contaminated soil and pore fluid. Hence, characterizing the mechanisms governing movement of air through saturated porous media is therefore critical to the design of an effective cleanup treatment. However, in spite of the success of air sparging as a remediation technique for the clean-up of contaminated soils, to date, the fundamental mechanisms or the physics …

Development Of X-Ray Holography Methods For Structure Determination : Application Of High Speed Detectors And Novel Numerical Methods, Yuhao Wang

Dissertations

Holographic methods show much promise to enable direct determination of atomic structure with minimal assumptions and approximations. The approach can, in principle, provide three dimensional information on atomic positions. However, significant developments in experimental techniques, instrumentation and in data collection and analysis are needed. A review of the holography method is given with a focus on X-ray fluorescence holography. Methods for analysis of X-ray holographic data are also reviewed. An overview of the detectors relevant to X-ray measurements is also presented. An experimental apparatus for rapid acquisition of X-ray holographs using novel X-ray detectors has been developed. The integration of …

Distributed Spectrum Leasing Via Cooperation, Tariq Elkourdi

Dissertations

“Cognitive radio” networks enable the coexistence of primary (licensed) and secondary (unlicensed) terminals. Conventional frameworks, namely commons and property-rights models, while being promising in certain aspects, appear to have significant drawbacks for implementation of large-scale distributed cognitive radio networks, due to the technological and theoretical limits on the ability of secondary activity to perform effective spectrum sensing and on the stringent constraints on protocols and architectures.

To address the problems highlighted above, the framework of distributed spectrum leasing via cross-layer cooperation (DiSC) has been recently proposed as a basic mechanism to guide the design of decentralized cognitive radio networks. According …

Recommendations For “Kiwi” Exploring Different Techniques For Recommendations In A Kazakh Online Video Website, Tair Kuanyshev

Dissertations

The aim of this project is to build a recommender system for an online website based on an empirical study using real-world data. The real world data was taken from the website Www.kiwi.kz which is an online video sharing website, providing online video, broadcast and radio to users since 2009. The research problem sought to develop the most suitable recommender system for an online video sharing website and to evaluate the effectiveness of this model on the real world data. This research attempts to develop the recommender system which will suggest possibly interesting video clips for users on an online …

Hear3d: A Study Of Spatial Sounds Effect On Language Learning, Brendan Cregan

Dissertations

Spatial sound is the manipulation of audio to add the illusion of position to the source of the sound, i.e. making sounds seem to originate from behind you or from different points around a room. Headphones must be used to achieve the optimum level of 3D sound. At any time over half a billion people are learning languages with the aide of audio which is why and the study of the effect or potential effects that the spatial sounds have on language learning is particularly interesting. If the application of spatial sounds to educational audio clips could be shown to …

Sports Data Mining Technology Used In Basketball Outcome Prediction, Chenjie Cao

Dissertations

Driven by the increasing comprehensive data in sports datasets and data mining technique successfully used in different area, sports data mining technique emerges and enables us to find hidden knowledge to impact the sport industry. In many instances, predicting the outcomes of sporting events has always been a challenging and attractive work and is therefore drawing a wide concern to conduct research in this field. This project focuses on using machine learning algorithms to build a model for predicting the NBA game outcomes and the algorithms involve Simple Logistics Classifier, Artificial Neural Networks, SVM and Naïve Bayes. In order to …

E-Learning And Knowledge Management: The Development Of An E-Learning System For Organisational Training, Alan Muhire

Dissertations

Information technology has major role in most successful companies and organisations around the world, most companies are using IT to reduce operation cost, while improving customer service by providing service twenty four hours, seven days a week and improving communication that helps keep pace with competitors. In most companies and organisation training is a process carried out on a regular basis; the quality of training offered to employee will be reflected on how knowledgeable the staff will become resulting in the organisation becoming more successful. As organisations and companies are currently interested in improving knowledge management, employees are equally working …

Biometric Alternatives To Captcha: Exploring Accessible Interface Options, Anita Foley

Dissertations

In the computing domain the relationship between accessibility and security is a complex and evolving one; accessibility attempts to ensure that as wide a range of individuals as possible are granted access to systems, whereas security attempts to restrict access only to individuals who are entitled to access those systems. A key security concern is to determine whether or not the system is being accessed by a software agent or a real human being, and a number of approaches have been developed to determine the answer to this question. This issue has been discussed throughout the history of computer science …

Can A Self Assessement Tool For Environmental Controls Which Has Been Informed By Users Be Of Benefit To Potential Users, Sean Loughran

Dissertations

This dissertation looks at the area of environmental control systems (ECS) also known as electronic aids for daily living for people with disabilities. These systems allow an individual with a disability to control devices such as a television, music player, telephone as well as a door, window or curtain controllers. A self-assessment tool was developed for potential users, which was informed by the feedback of (i) users who use or who have used environmental control systems, (ii) Enable Ireland staff who were involved in the service delivery of ECS and (iii) companies who install ECS for individuals with disabilities. These …

The Effect Of Learning Styles And E-Learning Tools On The Training Of Ict To Digital Immigrants In Life Long Learning, Stephen Horan

Dissertations

The diversity of learners in the classroom has expanded significantly in the past twenty years, in a modern classroom it is unsurprising to see learners for whom English is not their first language, learners with specific learning difficulties, mature learners, learners attempting to return to work, etc., so much so that the 'typical' learner has become extinct. This research will look at the use of Information Communication Technology in Education by undertaking an investigation of how the use of ICT can aid learners, both digital natives and digital immigrants. The project will use learning styles at the core of an …

Development Of Student Centred Knowledge Management System Based In A Higher Education Institution, Chong Liu

Dissertations

With the emergence of a knowledge society and of information technology, knowledge has become a key resource to develop a sustained economy. It is a vital word in the Knowledge Management area (Awad & Ghaziri, 2004). Knowledge Management has also become vital to help knowledge organizations seek a competitive advantage. It also encourages members of organization to share knowledge and improve the organization‘s efficiency, performance, and competitiveness (Shin, 2004). Therefore, an increasing number of organizations have realized the necessity of knowledge management. Especially, the Higher Education Institute (HEI) as the extraordinary ―business‖ will be suitable for implementing knowledge management approaches …

Testing Mobile Web Applications For W3c Best Practice Compliance, Sean Mee

Dissertations

Adherence to best practices and standards when developing mobile web applications is important to achieving a quality outcome. As smartphones and tablet PCs continue to proliferate in the consumer electronics market, businesses and individuals are increasingly turning from the native application paradigm to HTML 5-based web applications as a means of software development and distribution. With an everincreasing reliance by users on the correct functioning of such applications, the requirement for stringent and comprehensive quality assurance measures is also brought sharply into focus. This research investigates the increasing trend towards mobile web application development in the mobile software domain, and …

Effective Knowledge Management System Implementation In Small Organisations., Orna Nicholl

Dissertations

Much of the key research in the field of Knowledge Management carries an inherent set of assumptions as to the nature of the organisations under investigation, such as the fact that the organisation is a large one. As a consequence of this, Knowledge Management papers tend to focus on the distinctions such as: management-led initiatives versus grassroots initiatives, and the importance of inter-departmental communications, but for smaller organisations these types of issues are minimised or completely absent. This project will look at models and techniques from the existing body of Knowledge Management literature (with its focus on larger organisations) and …

Accessible Information: Advocating The Use Of Technology For Individuals With Intellectual Disability On Their Path To Individualised Services, Michelle Moloney

Dissertations

Providing people with an intellectual disability (ID), opportunities for social integration have been shown to have a reliable positive influence on their well-being (Wehmeyer et al., 2006; Bunning, 2009). A large percentage of individuals with ID are unable to read and write. For this reason in order for the person to make an informed choice the person needs to have good information presented in a way that they can understand. They may need to see tangible visual aids (video, role play, film, photographs). It may need to be demonstrated to them a number of times. This assists a person in …

Investigation And Analysis Of Open Government Data In Ireland, And The Creation Of A Set Of Quality Guidelines To Aid Its Utility Within Mobile Application Development, Peadar Fitzpatrick

Dissertations

Governments are the custodians of vast amount of data. While some of this data may be sensitive in nature, in that it contains personal or confidential information, much of it is in the public interest. Recent years has seen the emergence of Open Government Data (OGD) where governments are now actively making their data available in open and electronically accessible formats. The motivation for the production of such data includes a desire to increase transparency but also a desire to realise the economic potential associated with re-use of this data. A key usage area for this data to date has …

An Investigation Into Obstacles Effecting The Use Of Support Technology For Accommodation Facilitation In Third Level Education, Conor Brennan

Dissertations

The profile of students attending third level education in Ireland has changed over the past number of years. More non-traditional students have entered mainstream education. These non-traditional students may be mature students, students whose first language is not English and students with disabilities. In the 2010-2011 academic session 6,932 students with disabilities were enrolled in third level education. This represent 3.9%(AHEAD 2011) of all students enrolled in third level education, which constitutes a 10% increase on 2009-2010. This increase is putting pressure on an already strained system. Efforts have been made to educate and inform lecturers and teaching staff on …

Cloud Computing Adoption For Smes: Challenges, Barriers And Outcomes, Mojtaba Akbari

Dissertations

In spite of all the excitement and fuss around cloud computing technologies in recent years, it is believed that the industry has been to some extent lagging behind when it comes to the deployment of cloud technologies and migration from legacy Information Technology (IT) infrastructure. This research aims to investigate the influential factors that impact adoption of cloud-based technologies by various organizations. More specifically, this research focuses on the behaviour of Small and Medium Enterprises (SMEs) rather than larger organizations. Such classification is crucial since the constraints applicable to SMEs are different to their larger counterparts and subsequently the decision …

The Prevailing Obstacles In Web Accessibility On Three Well-Known Websites For Older People With Sight Difficulties, Sarah O'Reilly

Dissertations

Prior research has argued that there is no one best approach to evaluating web accessibility and proposes the adoption of multiple approaches. Following these proposals this research used three different approaches for evaluating accessibility on websites for accessibility to older persons with sight difficulties as there are advantages and disadvantages to each approach. Approached used included: (1) Using automated tools to determine accessibility, which looks at the code of websites to get a general overview of accessibility issues. (2) Manually looking at the design, code and also how it might impact the user. This involved a manual assessment of each …

Towards Universally Designed Assistive Technology E-Learning, Karl O'Keeffe

Dissertations

The aim of this dissertation is to provide Assistive Technology (AT) professionals involved in the area of education and training with a set of reusable technological tools and techniques that will enable them to increase the reach, efficiency, effectiveness and accessibility of their training through online delivery. There are a number of broadly accepted reasons why an organisation in any field might choose to make training available online or partially online (blended) rather than relying on traditional face to face methods. Of the four considered here and mentioned above, accessibility is the biggest concern in the context of AT. It …

The Effects Of Deposition Conditions On Rf Sputtered Gallium Tin Zinc Oxide Thin Film Transistors, Tanina Bradley

Dissertations

Thin film transistors (TFTs) were fabricated with a transparent amorphous gallium tin zinc oxide (GSZO) channel layer. GSZO is a promising, low cost replacement for the commonly used indium gallium zinc oxide (IGZO).The transistors were fabricated on Si substrates to optimize performance prior to transferring device production to flexible substrates. This dissertation will address the effects of deposition and post-deposition parameters on the film properties and interface traps. It will also address the parameters’ resultant effects on device performance and stability with the use of various characterization techniques. Film properties were studied using x-ray diffraction (XRD) and transmission measurements to …