Engineering Commons^™

Bit Error Rate Estimation In Wimax Communications At Vehicular Speeds Using Nakagami-M Fading Model, Biswojit Bose

Theses: Doctorates and Masters

The wireless communication industry has experienced a rapid technological evolution from its basic first generation (1G) wireless systems to the latest fourth generation (4G) wireless broadband systems. Wireless broadband systems are becoming increasingly popular with consumers and the technological strength of 4G has played a major role behind the success of wireless broadband systems. The IEEE 802.16m standard of the Worldwide Interoperability for Microwave Access (WiMAX) has been accepted as a 4G standard by the Institute of Electrical and Electronics Engineers in 2011. The IEEE 802.16m is fully optimised for wireless communications in fixed environments and can deliver very high …

Effect Of Thermal Annealing And Carbon Implantation On The Functional Properties Of Nanocomposite Tisin Coatings On Steel, Mohammad Shoeb Ahmed

Theses: Doctorates and Masters

This PhD research contributes to the part of advanced materials technology. The machining industry currently faces tremendous pressures with the need for durable cutting tools suitable for eco-friendly high speed machining operations becoming acute. In this thesis innovative design and synthesis strategies are explored to tailor the properties of nanocomposite coatings. Advanced characterisation techniques are applied to identify the mechanisms that control the mechanical, tribological, and corrosion behaviours of these coatings. Cutting tools protected by these coatings are anticipated to exhibit a unique combination of superior toughness and greater resistance to wear and corrosion, providing significant economic and environmental benefits. …

Opto-Vlsi-Based Adaptive Optical Power Splitter/Combiner For Next Generation Dynamic Optical Telecommunication Networks, Haithem A. Mustafa

Theses: Doctorates and Masters

The demand for optical power splitters is growing globally, due to the rapid deployment of fibre-to-the-premises, optical metropolitan area network (MAN), and active optical cables for TV/Video signal transport. Optical splitters play an important role in passive optical network (PON) technology by enabling several hundred users to share one optical line terminal. However, current PONs, which use fixed optical power splitters, have limited reconfigurability particularly in adding/dropping users to/from an optical network unit.

An adaptive optical power splitter (OPS) can dynamically reallocate the opticalpower in the entire network according to the real-time distribution of users and services, thus providing numerous …

Investigation On The Mobile Robot Navigation In An Unknown Environment, Ahmed S. Khusheef

Theses: Doctorates and Masters

Mobile robots could be used to search, find, and relocate objects in many types of manufacturing operations and environments. In this scenario, the target objects might reside with equal probability at any location in the environment and, therefore, the robot must navigate and search the whole area autonomously, and be equipped with specific sensors to detect objects. Novel challenges exist in developing a control system, which helps a mobile robot achieve such tasks, including constructing enhanced systems for navigation, and vision-based object recognition. The latter is important for undertaking the exploration task that requires an optimal object recognition technique.

In …

An Integrated Computer-Aided Modular Fixture Design System For Machining Semi-Circular Parts, Uday H. Farhan

Theses: Doctorates and Masters

Productivity is one of the most important factors in manufacturing processes because of the high level of market competition. In this regard, modular fixtures (MFs) play an important role in practically improving productivity in flexible manufacturing systems (FMSs) due to this technology using highly productive computer numerical control (CNC) machines. MFs consist of devices called jigs and fixtures for accurately holding the workpiece during different machining operations. The design process is complex, and traditional methods of MF design were not sufficiently productive.

Computer-aided design (CAD) software has rapidly improved as a result of the development of computer technology, and has …

Characterising The Deformation Behaviour Of Human Tooth Enamel At The Microscale, Simona O'Brien

Theses: Doctorates and Masters

Enamel plays an important role in tooth function. Optimal combinations of composition and structure endow enamel with unique mechanical properties that remain largely unexplored. Specifically, more detailed understanding of the loadbearing ability of enamel is needed to mimic it synthetically and to design next generation biocomposite materials. This research investigates the variables that influence deformation behaviour of tooth enamel in relation to its hierarchical structure. Initially, a new method was developed for preparing flat, finely polished tooth samples that were maintained in their normal hydrated state for nanoindentation testing. In contrast to conventional methods, which commonly utilise either inappropriate or …

On A Joint Physical Layer And Medium Access Control Sublayer Design For Efficient Wireless Sensor Networks And Applications, Mahir Lumumba Meghji

Theses: Doctorates and Masters

Wireless sensor networks (WSNs) are distributed networks comprising small sensing devices equipped with a processor, memory, power source, and often with the capability for short range wireless communication. These networks are used in various applications, and have created interest in WSN research and commercial uses, including industrial, scientific, household, military, medical and environmental domains. These initiatives have also been stimulated by the finalisation of the IEEE 802.15.4 standard, which defines the medium access control (MAC) and physical layer (PHY) for low-rate wireless personal area networks (LR-WPAN).

Future applications may require large WSNs consisting of huge numbers of inexpensive wireless sensor …

Surface Plasmons For Enhanced Metal-Semiconductor-Metal Photodetectors, Ayman A. Karar

Theses: Doctorates and Masters

Surface Plasmon Polaritons (SPPs) are quantized charge density oscillations that occur when a photon couples to the free electron gas of the metal at the interface between a metal and a dielectric. The extraordinary properties of SPP allow for sub-diffraction limit waveguiding and localized field enhancement. The emerging field of surface plasmonics has applied SPP coupling to a number of new and interesting applications, such as: Surface Enhanced Raman Spectroscopy (SERS), super lenses, nano-scale optical circuits, optical filters and SPP enhanced photodetectors. In the past decade, there have been several experimental and theoretical research and development activities which reported on …

Optimal Power Generation In Microgrids Using Agent-Based Technology, Thair Mahmoud

Theses: Doctorates and Masters

The existing power grids that form the basis of the respective electrical power infrastructures for various states and nations around the world, are expected to undergo a period of rapid change in the near future. The key element driving this change is the emergence of the Smartgrid. The Smartgrid paradigm represents a transition towards an intelligent, digitally enhanced, two-way power delivery grid. The aim of the Smartgrid is to promote and enhance the e_cient management and operation of the power generation and delivery facilities, by incorporating advanced communications, information technology, automation, and control methodologies into the power grid proper. Smartgrid's …

Optimal Control Of Power Quality In Microgrids Using Particle Swarm Optimisation, Waleed Abood Baddai Al-Saedi

Theses: Doctorates and Masters

Driven by environmental protection, economic factors, conservation of energy resources, and technical challenges, the microgrid has emerged as an innovative small-scale power generation network. Microgrids consist of a cluster of Distributed Generation units that encompass a portion of an electric power distribution system and may rely on different energy sources. Functionally, the microgrid is required to provide adequate levels and quality of power to meet load demands. The issue of power quality is significant as it directly affects the characteristics of the microgrid’s operation. This problem can be defined as an occurrence of short to long periods of inadequate or …

A Model For Systematically Investigating Relationships Between Variables That Affect The Performance Of Novice Programmers, Vivian Campbell

Theses: Doctorates and Masters

This research was motivated by an interest in novices learning to program

and a desire to understand the factors that affect their learning. The

traditional approach to performing such an investigation has been to select

factors which may be important and then perform statistical tests on a few

potential relationships. A new research model is proposed and tested to

ensure that a thorough and systematic investigation of the data is performed.

This thesis describes the data, defines the model and explains the

application and validation of the model.

The research process is managed by a control algorithm that is the …

Silver (Ag) Nanoparticle Based Masks For The Development Of Antireflection Subwavelength Structures In Gaas And Si Solar Cells, Nazme A. Moushumy

Theses: Doctorates and Masters

This thesis focuses on the design and development of silver nanoparticles that can be used as masks for the development of antireflection subwavelength grating (SWG) structures. We particularly investigate the impact of silver thin film thickness and the effect of annealing temperature on the fabrication of silver nanoparticles of controlled size and spacing distributions. We also use these measured distributions to predict the performance of subwavelength grating structures developed using dry and isotropic etching of semiconductor substrates.

Silver (Ag) thin films of different thicknesses are deposited on Silicon (Si) and Gallium Arsenide (GaAs) semiconductor substrates and annealed at different temperatures. …