The research problem considered in this thesis was presented by NATS, who are responsible for the take-off runway scheduling at London Heathrow airport. The sequence in which aircraft take off is very important and can have a huge effect upon the throughput of the runway and the consequent delay for aircraft awaiting take-off. Sequence-dependent separations apply between aircraft at take-off, some aircraft have time-slots within which they must take-off and all re-sequencing performed by the runway controller has to take place within restrictive areas of the airport surface called holding areas. Despite the complexity of the task and the short decision time available, take-off sequencing is performed manually by runway controllers. In such a rapidly changing environment, with much communication and observation demanded of the busy controller, it is hardly surprising that sub-optimal mental heuristics are currently used. The task presented by NATS was to develop the decision-making algorithms for a decision support tool to aid a runway controller to solve this complex real-world problem. A design for such a system is presented in this thesis. Although the decision support system presents only a take-off sequence to controllers, it is vitally important that the movement within the holding area that is required in order to achieve the re-sequencing is both easy to identify and acceptable to controllers. A key objective of the selected design is to ensure that this will always be the case. Both regulatory information and details of controller working methods and preferences were utilised to ensure that the presented sequences will not only be achievable but will also be acceptable to controllers. A simulation was developed to test the system and permit an evaluation of the potential benefits. Experiments showed that the decision support system found take-off sequences which significantly reduced the delay compared with those that the runway controllers actually used. These sequences had an equity of delay comparable with that in the sequences the controllers generated, and were achieved in a very similar way. Much of the benefit that was gained was a result of the decision support system having visibility of the taxiing aircraft in addition to those already queueing for the runway. The effects of uncertainty in taxi times and differing planning horizons are explicitly considered in this thesis. The limited decision time available ensures that it is not practical for a runway controller to consider as many aircraft as the decision support algorithms can. The results presented in this thesis indicate that huge benefits may be possible from the development of a system to simplify the sequencing task for the controllers while simultaneously giving them greater visibility of taxiing aircraft. Even beyond these benefits, however, the system described here will also be seen to have further potential benefits, such as for evaluating the effects of constraints upon the departure system or the flexibility of holding area structures.

Smart Card devices are commonly used on many secure applications where there is a need to identify the card holder in order to provide a personalised service. The value of access to locked data and services makes Smart Cards a desirable attack target for hackers of all sorts. The range of attacks a Smart Card and its environment can be subjected to ranges from social engineering to exploiting hardware and software bugs and features. This research has focused on several hardware related attacks and potential threats. Namely, power glitch attack, power analysis, laser attack, the potential effect on security of memory power consumption reduction techniques and using a re-configurable instruction set as method to harden opcode interpretation. A semi-automated simulation environment to test designs against glitch attacks and power analysis has been developed. This simulation environment can be easily integrated within Atmel’s design flow to bring assurance of their designs’ behaviour and permeability to such attacks at an early development stage. Previous power analysis simulation work focused on testing the implementation of part of the cryptographic algorithm. This work focuses on targeting the whole algorithm, allowing the test of a wider range of countermeasures. A common glitch detection approach is monitoring the power supply for abnormal voltage values and fluctuations. This approach can fail to detect some fast glitches. The alternative approach used in this research monitors the effects of a glitch on a mono-stable circuit sensitive to fault injection by glitch attacks. This work has resulted in a patented glitch detector that improves the overall glitch detection range. The use of radiation countermeasures as laser countermeasures and potential sensors has been investigated too. Radiation and laser attacks have similar effects on silicon devices. Whilst several countermeasures against radiation have been developed over the years, almost no explicit mention of laser countermeasures was found. This research has demonstrated the suitability of using some radiation countermeasures as laser countermeasures. Memory partitioning is a static and dynamic power consumption reduction technique successfully used in various devices. The nature of Smart Card devices restricts the applicability of some aspects of this power reduction technique. This research line has resulted in the proposal of a memory partitioning approach suitable to Smart Cards.

The heart is a non-regenerating organ that gradually suffers a loss of cardiac cells and functionality. Given the scarcity of organ donors and complications in existing medical implantation solutions, it is desired to engineer a three-dimensional architecture to successfully control the cardiac cells in vitro and yield true myocardial structures similar to native heart. This thesis investigates the synthesis of a biocompatible gelatin methacrylate hydrogel to promote growth of cardiac cells using biotechnology methodology: surface acoustic waves, to create cell sheets. Firstly, the synthesis of a photo-crosslinkable gelatin methacrylate (GelMA) hydrogel was investigated with different degree of methacrylation concentration. The porous matrix of the hydrogel should be biocompatible, allow cell-cell interaction and promote cell adhesion for growth through the porous network of matrix. The rheological properties, such as polymer concentration, ultraviolet exposure time, viscosity, elasticity and swelling characteristics of the hydrogel were investigated. In tissue engineering hydrogels have been used for embedding cells to mimic native microenvironments while controlling the mechanical properties. Gelatin methacrylate hydrogels have the advantage of allowing such control of mechanical properties in addition to easy compatibility with Lab-on-a-chip methodologies. Secondly in this thesis, standing surface acoustic waves were used to control the degree of movement of cells in the hydrogel and produce three-dimensional engineered scaffolds to investigate in-vitro studies of cardiac muscle electrophysiology and cardiac tissue engineering therapies for myocardial infarction. The acoustic waves were characterized on a piezoelectric substrate, lithium niobate that was micro-fabricated with slanted-finger interdigitated transducers for to generate waves at multiple wavelengths. This characterization successfully created three-dimensional micro-patterning of cells in the constructs through means of one- and two-dimensional non-invasive forces. The micro-patterning was controlled by tuning different input frequencies that allowed manipulation of the cells spatially without any pre- treatment of cells, hydrogel or substrate. This resulted in a synchronous heartbeat being produced in the hydrogel construct. To complement these mechanical forces, work in dielectrophoresis was conducted centred on a method to pattern micro-particles. Although manipulation of particles were shown, difficulties were encountered concerning the close proximity of particles and hydrogel to the microfabricated electrode arrays, dependence on conductivity of hydrogel and difficult manoeuvrability of scaffold from the surface of electrodes precluded measurements on cardiac cells. In addition, COMSOL Multiphysics software was used to investigate the mechanical and electrical forces theoretically acting on the cells. Thirdly, in this thesis the cardiac electrophysiology was investigated using immunostaining techniques to visualize the growth of sarcomeres and gap junctions that promote cell-cell interaction and excitation-contraction of heart muscles. The physiological response of beating of co-cultured cardiomyocytes and cardiac fibroblasts was observed in a synchronous and simultaneous manner closely mimicking the native cardiac impulses. Further investigations were carried out by mechanically stimulating the cells in the three-dimensional hydrogel using standing surface acoustic waves and comparing with traditional two-dimensional flat surface coated with fibronectin. The electrophysiological responses of the cells under the effect of the mechanical stimulations yielded a higher magnitude of contractility, action potential and calcium transient.

Fire has been always a major concern for designers of steel and concrete structures. Designing fire-resistant structural elements is not an easy task due to several limitations such as the lack of fire-resistant construction materials. Concrete reinforcement cover and external insulation are the most commonly adopted systems to protect concrete and steel from overheating, while spalling of concrete is minimised by using HPFRC instead of standard concrete. Although these methodologies work very well for low rise concrete structures, this is not the case for high-rise and inaccessible buildings where fire loading is much longer. Fire can permanently damage structures that cost a lot of money. This is unsafe and can lead to loss of life. In this research, the author proposes a new type of main reinforcement for concrete structures which can provide better fire-resistance than steel or FRP re-bars. This consists of continuous braided fibre rope, generally made from fire-resistant materials such as carbon or glass fibre. These fibres have excellent tensile strengths, sometimes in excess of ten times greater than steel. In addition to fire-resistance, these ropes can produce lighter and corrosive resistant structures. Avoiding the use of expensive resin binders, fibres are easily bound together using braiding techniques, ensuring that tensile stress is evenly distributed throughout the reinforcement. In order to consider braided ropes as a form of reinforcement it is first necessary to establish the mechanical performance at room temperature and investigate the pull-out resistance for both unribbed and ribbed ropes. Ribbing of ropes was achieved by braiding the rope over a series of glass beads. Adhesion between the rope and concrete was drastically improved due to ribbing, and further improved by pre-stressing ropes and reducing the slacked fibres. Two types of material have been considered for the ropes: carbon and aramid. An implicit finite element approach is proposed to model braided fibres using Total Lagrangian formulation, based on the theory of small strains and large rotations. Modelling tows and strands as elastic transversely isotropic materials was a good assumption when stiff and brittle fibres such as carbon and glass fibres are considered. The rope-to-concrete and strand-to-strand bond interaction/adhesion was numerically simulated using newly proposed hierarchical higher order interface elements. Elastic and linear damage cohesive models were used effectively to simulate non-penetrative 'free' sliding interaction between strands, and the adhesion between ropes and concrete respectively. Numerical simulation showed similar de-bonding features when compared with experimental pull-out results of braided ribbed rope reinforced concrete.

Condition monitoring of rotating machinery and machine systems has attracted extensive researches, particularly the detection and diagnosis of machine faults in their early stages to minimise maintenance cost and avoid catastrophic breakdowns and human injuries. As an efficient mechanical system, helical gearbox has been widely used in rotating machinery such as wind turbines, helicopters, compressors and internal combustion engines and hence its vibration condition monitoring is attracting substantial research attention worldwide. However, the vibration signals from a gearbox are usually contaminated by background noise and influenced by operating conditions. It is usually difficult to obtain symptoms of faults at the early stage of a fault. This study focus on developing effective approaches to the detection of early stage faults in an industrial helical gearbox. In particular, continuous wavelet transformation (CWT) has been investigated in order to select an optimal wavelet to effectively represent the vibration signals for both noise reduction and fault signature extraction. To achieve this aim, time synchronous average (TSA) is used as a tool for preliminary noise reduction and mathematical models of a gearbox transmission system is developed for characterising fault signatures. The performance of three different wavelet families was compared and henceforth a criterion and method for the selection of the most discerning has been established. It has been found that the wavelet that gives the highest RMS value for the baseline vibration signal will show the greatest difference between baseline and gearbox vibration with a fault presence. Comparison of the three wavelets families shows that the Daubechies order 1 can give best performance for feature extraction and fault detection and fault quantification. However, there are limitations that undermine CWT application to fault detection, in particular the difficulty in selecting a suitable wavelet function. A major contribution of this research programme is to demonstrate a possible route on how to overcome this deficiency. An adaptive Morlet wavelet transform method has been proposed based on information entropy optimization for analysing the vibration signal and detecting and quantifying the faults seeded into the helical gearbox. This research has also developed a nonlinear dynamic model of the two-stage helical gearbox involving time–varying mesh stiffness and transmission error. Based on experimental data collected with different operating loads and the simulating results vibration signatures for gear faults are fully understood and hence confirms the CWT based scheme for signal enhancement. These results also indicate that the dynamic model can be used in studying gear faults and would be useful in developing gear fault monitoring techniques.

To best comprehend cellular behaviour and how it determines cell migration in metastatic cancer, the research described here has focused on cell mechanics. The signalling pathway involving Rho-associated kinase (ROCK) has emerged as being the main regulator for the cellular cytoskeleton and actomyosin contractility that play key roles in metastatic cancer formation. In this thesis, an examination is made of how the cellular properties intertwine as ROCK is overexpressed. In research towards being able to measure and describe the viscoelastic properties of a cell that are associated with cell mechanics, over a wide range of timescales, a novel AFM force indentation data analysis method was applied. In particular, as part of this study, pancreatic ductal adenocarcinoma (PDAC) cells were overexpressed with ROCK, and the influence of ROCK activity on cell’s elastic and viscoelastic properties were quantified. It was found that when ROCK activity was overexpressed in cells, their elasticity decreased while their viscosity remained unchanged. These properties had a direct correlation with the activity of ADF/cofilin - the proteins downstream of ROCK. This meant that with overexpression, more stable actin bundles were present along with their inward stresses generated by the actomyosin contraction. This is consistent with an increased level of compressive forces within cells. Collective compressive forces between cell-cell are associated with the packing of cells that decreases cellular response. To further understand the role of ROCK activity in cancer invasion, a microfluidic device was created to mimic cell migration through tissue. The device consists of precisely defined microchannels with dimensions chosen to hinder and confine the cells in a manner similar to that found in a physiological environment. It was found that overexpressed ROCK1 cells in the confinement had notable decrease in cell size and motility. Along with this decrease in mechanical properties, observations also gave rise to questions about the connection between these properties that remain to be answered.

Airport terminals are characteristic for the large and open spaces with diverse and transient population. They are designed predominantly as indoor spaces while the overwhelming majority is people in transient conditions. Dressing code and activity, along with dwell time and overall expectations are differentiating factors for variations in thermal requirements between passengers and staff. The diversity of spaces and the heterogeneous functions across the different terminal zones further contribute to this differentiation, which results in thermal comfort conflicts and often in energy wastage. Understanding such conflicts and the comfort requirements can improve thermal comfort conditions while reducing the energy consumed for the conditioning of these energy-intensive buildings. Through extensive field surveys, the study investigated the thermal comfort conditions in three airport terminals of different size and typology. The seasonal surveys included extensive environmental monitoring across the different terminal areas and over 3,000 questionnaire-guided interviews with passengers, staff, well-wishers and other short stay visitors. The findings demonstrate a preference for a different thermal environment than the one experienced and that thermal neutrality lies at lower temperatures. The comfort requirements for passengers and staff are evaluated and shown to differ significantly. Neutral temperature for passengers is lower by 0.6 - 3.9 °C. In accordance with the neutrality discrepancies, passengers prefer cooler temperatures than staff by 0.4 - 2.0 °C. Employees have limited adaptive capacity that leads in a narrower comfort zone, whereas passengers consistently demonstrate higher tolerance of the thermal environment and a wider range of comfort temperatures. Furthermore, the findings highlight the complex nature of thermal comfort in airport terminals, where the desired thermal state for more than half the occupants is other than neutral and a multitude of design and operational characteristics influence the indoor environment.

Protecting Cloud services located within the Cloud Computing centre easily would be a significant advantage in the current Cloud computing market. However, the existing encryption system all process a notable weakness that the private key must be stored locally, so could be accessed and used to break the encryption. To solve this problem, a novel technology has been investigated that recompose the private key by using the properties and behaviours extracted from a Cloud server during execution. This thesis will investigate the feasibility of this approach by analysing simple online programs which would typically form the basis or components of larger systems and thereby indicate, by the ability to distinguish such simple systems, which larger real world practical systems may also be distinguished. The private key does not need to store in the system, which this paper has proved such a system is feasible to be applied in the current encryption system.

The principle aims of this thesis were to investigate the influence of intrinsic navigational cues in virtual environments and video games. Modern video games offer complex environments that may reflect real world spaces or represent landscapes from fantasy and fiction. The coherent design of these spaces can promote natural navigational flow without the requirement for extraneous guidance such as maps and arrows. The methods that designers use to create natural flow are complex and stratified utilising principles rooted in urban architectural design and navigational cues that are intrinsic to real-world wayfinding scenarios. The studies presented in this thesis analysed not only these commonly used architectural cues but also the potential for the reinforcing of these cues by the addition of lighting, visual and auditory cues. The primary focus of this thesis was a systematic and quantitatively rooted analysis of the impact lighting has on navigation and the levels at which variance in lighting makes a quantifiable difference to navigational choices within a virtual environment. The findings of this thesis offer clear guidance as to the influence that lighting has within virtual environments and specifies that thresholds at which the inclusion of guidance lighting begins to affect navigational choices and the levels that players become conscious of these cues. The thesis also analyses the temporal thresholds for the detection of changes in contrast, hue and texture within an environment. The relationship of other intrinsic cues such as the potential reinforcement or cue competition effects of both audio and other visual cues, for instance motion are quantitatively analysed. These data were reflected in the form of a series of heuristic design principles that augment those that underpin architectural and environmental design considerations by for instance suggesting levels of saliency for lighting cues or reinforcing existing cues via supporting audio guidance.

The modern society is in the transition process from the Information Age to the Interaction Age so the attitude of academics and students towards Internet use is continuously changing. This study aims to investigate the attitudes of lecturers and students from Al-Zawiya University (AZU), Libya, towards the use of Internet technology for academic purposes and to formulate a set of recommendations for upgrading the quality and effectiveness of ICT implementation within the School of Engineering from AZU. The action research approach is used to develop a novel framework for increasing the effectiveness of ICT implementation in AZU. The framework aims to improve the Internet skills of lecturers and students, increase the impact of the Internet on their academic efficiency, solve the problems they face while using the Internet, and increase their satisfaction with the Internet facilities provided by AZU. This new framework is built on the basis of different existing models and frameworks (a two-dimensional model for ICT integration in education, the ASSURE model, an framework for HE internationalisation, the ICube model for teaching and learning activities in modern Higher Education institutions). The study includes an analysis of existing Internet use by academic staff and students which looks at various features of Internet usage, including purposes for using the Internet and users’ level of satisfaction with the Internet facilities provided by the university. The SPSS package is employed for qualitative analysis of sixty students’ answers to the questionnaires and shows that people’s skills, computing resources and infrastructure influence the efficacy of integrating computers into HE. Semi-structured interviews are used to determine the attitudes of twelve academics towards use of the Internet in two departments – Department of English Language (DEL) and Department of Electrical Engineering (DEE). The qualitative analysis of academics’ responses identifies the cognitive, performance and affective components of their outlook towards use of the Internet for teaching and research. In addition, the relationship between their answers and the research hypotheses shows that a combination of individual and social factors affects users’ perspectives regarding Internet usage. Finally, a set of recommendations for the enhancement of ICT implementation within the School of Engineering at Al-Zawiya University in Libya is formulated, aiming to enhance the quality of teaching, learning and research activities and the level of students’ satisfaction with the technology-enhanced approach to learning. The findings of this thesis might be of interest to managers, academics and other people involved in the design and development of strategies for ICT implementation in Libyan universities and similar developing countries.