This doctoral dissertation examines whether incumbency affects democracy, and if it does, how re-election impacts on the political system. This thesis links and extends two theoretical traditions that hardly ever have been combined: political support theory and incumbency theory. Political support theory is used as a proxy to examine democracy from a multidimensional perspective. In this theoretical tradition, there has been a considerable concentration of studies on developed nations, and which take a comparative approach. Also, there is persistently inadequate attention given to measuring the form of a government, with a strong predominance of parliamentarian systems. Likewise, most of the research is focused at the individual level, in where the use of statistical techniques is prevailing, and the mixed methods are, nearly, non-existent. On the other hand, there are no studies that explain incumbency effects on democracy directly. Despite there being plenty of inferences which can be taken from incumbency analysis and its extrapolations about democracy and elections, there is a scarcity of studies that associate both political phenomena. In most cases, scholars analyse incumbency as an advantage in popular elections in developed countries, mainly the U.S. The main argument of this thesis proposes that incumbency has effects on democracy and that those impacts will have adverse consequences on the democratic system. Taking Chile as a case-study, a developing country with a presidential system and with similarities to Western party systems, this research seeks to respond three hypotheses. 1) The categories of support identified by Booth and Seligson in 2009 could, to an extent, be modified by including questions that gauge the role of the presidential institution in the Chilean political system. 2) It is expected that incumbency will be shown to have distinct impacts on democratic political legitimacy. 3) The effect of deputies' re-election on political legitimacy dimensions will depend on the composition of legislative pairs at the electoral district level in Chile: two newcomers, one newcomer and one incumbent, or two incumbents. This investigation uses a mixed method strategy. From a qualitative perspective, I characterise all law bills proposed to the NC to limit the re-elections of public authorities in Chile, between 11th March 1990 and 31st December 2016. In line with this doctoral dissertation's aims, a context analysis is used to analyse the content of draft laws related to incumbency. From a quantitative approach, I examine the legislative incumbency effects on political legitimacy dimensions in Chile, from 2008 to 2014. In line with this doctoral dissertation's aim, a series of statistical techniques are used to analyse the effects of incumbency on political support. The findings suggest that: 1) The effects of incumbency are distributed differently according to the component of political legitimacy. 2) The rotation of political elites (seniority and the circulation of elected deputies) is the most substantial incumbency dimension to explain political support in comparison with the competition dimension. 3) The three indicators based on the margin of victory are only related negatively to support for government management. 4) The HDI has effects on political support, but they were inconsistent. 5) The legislative pair composition produces a moderator effect on incumbency indicators. 6) Politics and ideology play a pivotal role in understanding and explaining political support theory. This research concludes that is necessary to keep expanding studies that relate incumbency and democracy by taking other countries with different electoral systems, that arguments hold by politicians should be adjusted considering evidence, and it is imperative to reduce the perception-facts gap in citizens.

Significant penetration of distributed generation (DG) and the increasing automation level available for distribution networks have opened an option of splitting a network into subsystems and operating each as an "autonomous island". This is particularly important when a major contingency occurs. However, there are issues and challenges that must be addressed before islanded operation becomes viable, among which, ensuring seamless switching of a distribution subsystem from grid-connected to islanded mode is critically important. Unless the subsystem is a predesigned microgrid, it is highly possible that the subsystem load demand will exceed the generation capacity of island DGs. Therefore, an appropriate load shedding scheme must be implemented to ensure the islanded subsystem is power balanced. In this thesis, a switching control strategy is designed to deliver seamless islanding switching. This strategy comprises a multiple-DG coordination method and a single-step load shedding scheme. Mathematical studies and time-domain simulations that investigate the transients observed during the islanding switching process are both conducted, and together, they are used to address the transient stability issues of an islanded subsystem. This thesis focuses on a distribution subsystem consisting of a mix of synchronous and inverter-based DGs and a combination of static and dynamic loads. DG modelling and control is first introduced, and based on that, various types of method to achieve multiple-DG coordination, including an innovative multiple-master strategy, are investigated. The widely accepted master-slave strategy is used to coordinate DGs when the subsystem is islanded. The strategy demands a single dispatchable and controllable DG, such as a synchronous generator, to be the master, whilst requires the others, such as intermittent renewable-based DGs, to be the slaves. Dynamic load modelling is another critical part of this thesis. The transient stability of dynamic loads after major disturbances is investigated and then used to design the stability-oriented load shedding priority. The single-step load shedding scheme calculates the load shedding amount based on the power flow at the point of common coupling (PCC) and the spinning reserve available in the island. This scheme is activated by the tripping event of the PCC circuit breaker between the grid and the island, and then priorities the load to be shed according to the priority predetermined from the stability perspective. Mathematical analysis is first conducted on a simple subsystem to investigate the impact of DG settings on the islanding transients. A full-scale subsystem is also simulated in PSCAD/EMTDC and used to verify the effectiveness of the switching control strategy. In time-domain simulations, the subsystem is islanded following either a routine switching event or a permanent grid fault. Various factors that may affect the transient performance are analysed, such as the severity of the fault, the DG penetration level, the fault clearance time and the switching control delay. This thesis concludes that based on the proposed switching control strategy, the concept of seamless switching from grid-connected to islanded operation is technically viable.

Seismic events around the globe directly affect all ranges of structures, from complex and expensive ‘skyscrapers’ to simple frame structures, the latter making up a higher proportion of the number of structures affected as they are a much more common type of structure. The impact of a seismic event can be devastating, especially if adequate predictions of their impact and imposed structural response are not made during the design stage of the structure. Knowing what response to expect allows the engineer to design the structure to survive an event and protect the occupants. The structural response to a seismic event is very complex and can be affected by a wide range of structural, geotechnical and environ parameters. While larger, expensive structures make use of expensive, time consuming, finite element analytical procedures to determine their response the cheaper, simpler, frame structures have to make do with existing, simplified, spectral method predictions. This research firstly involves finite element analysis of simple frame structures, considering different structural and geotechnical parameters which may influence the seismic response, namely the stiffness of the structural joints, the geometry of the structure (influencing the individual structural element flexibility) and the foundation conditions (fixed base or shallow foundations with soil structure interaction). A range of frames, of varying geometry, are considered which mobilise different amounts of inter-storey drift, local rotation and global rotation response. The influence of soil structure interaction (SSI) and frame rigidity (i.e. the properties of the joints) on the response behaviour is investigated. The finite element database is then used to validate improved methods for predicting the spectral response parameters, specifically the natural period and damping of equivalent single degree of freedom (SDOF) systems, which include the effects of frame rigidity, geometry and SSI. Dynamic centrifuge testing is also carried out in order to further validate the improved spectral model for the case of real soil with shear dependant stiffness. The physical model testing is also extended to consider how environs, such as other structures in close proximity, influence the response of a structure.

Historic structures form a very important part of our cultural heritage and should be well protected. Therefore, full comprehension of the structural behavior of historic structures is of prior importance. A seriously damaged single domed mosque of 16th century Classical Ottoman Architecture was investigated in this study. Serious damages have been observed at various structural elements including the dome and the structural masonry walls, recently leading the structure&#039 / s closure to service. The main objective of this study is to find out the possible reasons of the damage. The Mosque was constructed on silty-clay soil and the water table has been changed considerably due to the drought in recent years causing soil displacements. The structure is modeled with linear finite element approach. The masonry walls are modeled with homogenized macro shell elements. The change in water table is imposed on the Mosque as displacement at foundation joints. The results of the analyses have been compared with the observed damage and the finite element model has been calibrated according to the observed damage. Some rehabilitation methods have also been proposed. Mini pile application up to firm soil (rock) was recommended to prevent the soil displacement. A steel ring around the damaged dome base was proposed to avoid any further propagation of cracks. Furthermore, the cracks on the masonry walls should also be repaired with a suitable material that is also compatible with the historic texture.

Separating unknown signal mixtures into their constituent parts is a difficult problem in signal processing called blind source separation. One of the benchmark problems in this area is the extraction of the fetal heartbeat from an electrocardiogram in which it is overshadowed by a strong maternal heartbeat. This thesis presents a study of a signal separation technique called independent component analysis (ICA), in order to assess its suitability for the maternal-fetal ECG separation problem. This includes an analysis of ICA on deterministic, stochastic, simulated and recorded ECG signals. The experiments presented in this thesis demonstrate that ICA is effective on linear mixtures of known simulated or recorded ECGs. The performance of ICA was measured using visual comparison, heart rate extraction, and energy, information theoretic, and fractal-based measures. ICA extraction of clinically recorded maternal-fetal ECGs mixtures, in which the source signals were unknown, were successful at recovering the fetal heart rate.

In screen-printed silicon-crystalline solar cells, the contact resistance of a thin interfacial glass layer between the silicon and the silver electrode plays a limiting role for electron transport. The motivation of this project is to gain increased understanding of the transport mechanisms of the electrons across this layer, which can be exploited to provide higher performance crystalline silicon solar cells. Our methodology throughout is to formulate and analyse mathematical models for the electron transport, based on the drift diffusion equations. In the first chapter we outline the problem and provide a summary of relevant theory. In Chapter 2 we formulate a one-dimensional model for electron transport across the glass layer, that we solve both numerically and by employing asymptotic techniques. Chapter 3 extends the model presented in Chapter 2 to two dimensions. To solve the two-dimensional model numerically we devise and validate a new spectral method. The short circuiting of current through thinner regions of the glass layer enables us to find limiting asymptotic expressions for the average current density for two different canonical glass layer profiles. In Chapter 4 we include quantum mechanical effects into the one-dimensional model outlined in Chapter 2 and find that they have a negligible effect on the contact resistance of the glass layer. We model the boundary effects present at the silicon emitter-glass interface in Chapter 5. Finally, in Chapter 6 we summarise our key results, suggest possible future work, and outline the implications of our work to crystalline silicon solar cell manufacturers.

The continuing growth in aviation has meant that the 35 largest airports in Europe reached saturation in 2005. The consequences have been increasing air traffic congestion, delays and associated costs. There is therefore a clear need to create more capacity. However, airports in particular and the air transport system in general are also subject to sudden fluctuations in demand and capacity. This research synthesizes the mechanisms of airport capacity fluctuations through the analytical formulation of concepts of capacity dynamics, capacity elasticities and capacity stability. It demonstrates the usability of these concepts through, firstly, a case study application to Brussels National Airport and, secondly, the development of a 'proof of concept' decision-support tool for strategic and tactical airport planning. Capacity dynamics and elasticities provide a performance indication as to how quickly capacity is able to change in response to fluctuations brought about by one or more capacity disrupters, whilst capacity stability provides airport planners with a measure of capacity robustness. These three concepts - capacity dynamics, elasticities and stability - contribute to a better a priori understanding of the airport system to be modelled. They demonstrate a better quantification of the impact and sensitivity of all the factors that affect runway capacity. It is also shown how the three concepts can assist in a better quantification of the risk of potential capacity fluctuation within the scope of airport planning. Based on this analytical formulation and quantification, mitigation should be an integral part of any effective airport plan in order to predict better the response to any given potential capacity degradation. It has been found that, from a capacity perspective, an airport becomes less stable the higher its level of performance. This capacity/stability paradox enables the ultimate goal of investment in capacity enhancement to be challenged, and it is legitimately questioned whether a similar investment would not be more worthwhile at secondary airports rather than at major airports.

Conceptual Modelling (CM) has received little attention in the area of Modelling and Simulation (M&S) and more specifically in Discrete Event Simulation (DES). It is widely agreed that CM is least understood despite its importance. This is however, not the case in other fields of science and engineering (especially, computer science, systems engineering and software engineering). In Computer Science (CS) alone, CM has been extensively used for requirements specification and some well-established methods are in practice. The aim of the thesis is to propose a CM framework based on the principles of software engineering and CS. The development of the framework is adapted from a well-known software engineering method called Structured Analysis and Design Technique (SADT), hence it is called SADT CM. It is argued that by adapting approaches from CS, similar benefits can be achieved in terms of formality, understanding, communication and quality. A comprehensive cross-disciplinary review of CM in CS and M&S is undertaken, which highlights the dearth of standards within M&S CM when compared to CS. Three important sub-fields of CS are considered for this purpose namely, information systems, databases and software engineering. The review identifies two potential methods that could be adopted for developing a M&S CM framework. The first method called PREView was found unsuitable for M&S CM in DES domain. Hence, the thesis concentrates on developing the framework based on SADT. The SADT CM framework is evaluated on three-in depth test cases that investigate the feasibility of the approach. The study also contributes to the literature by conducting a usability test of the CM framework in an experimental setting. A comprehensive user-guide has also been developed as part of the research for users to follow the framework.

This paper introduces the Mobile Process Landscaping (MPL) method for modelling, analysing and improving mobile business processes. Current approaches for process modelling and analysis do not explicitly allow the consideration of typical mobility issues, e.g. location-dependent activities, mobile networks as resources and specifics of mobile information systems. Thus, our method focuses on the modelling and analysis of these characteristics, and is furthermore based on the process landscaping approach, supporting the easy creation of hierarchical models of distributed processes. The method comes with a specialized modelling notation and guidelines for the creation of process landscapes, context models, and business object models. Furthermore, it provides a catalogue of formally defined evaluation objectives, targeting at typical mobility issues. Each evaluation objective can automatically be tested on the created process landscape. Furthermore, the method includes a best practices catalogue with patterns for process and application improvements for typical mobility situations. A validation of the method is presented showing results from the method’s use in a real-world project.

The convergence of multiservice heterogeneous networks and ever increasing Internet applications, like peer to peer networking and the increased number of users and services, demand a more efficient bandwidth allocation in optical networks. In this context, new architectures and protocols are needed in conjuction with cost effective quantitative methodologies in order to provide an insight into the performance aspects of the next and future generation Internets. This thesis reports an investigation, based on efficient simulation methodologies, in order to assess existing high performance algorithms and to propose new ones. The analysis of the traffic characteristics of an OC-192 link (9953.28 Mbps) is initially conducted, a requirement due to the discovery of self-similar long-range dependent properties in network traffic, and the suitability of the GE distribution for modelling interarrival times of bursty traffic in short time scales is presented. Consequently, using a heuristic approach, the self-similar properties of the GE/G/¿ are being presented, providing a method to generate self-similar traffic that takes into consideration burstiness in small time scales. A description of the state of the art in optical networking providing a deeper insight into the current technologies, protocols and architectures in the field, which creates the motivation for more research into the promising switching technique of ¿Optical Burst Switching¿ (OBS). An investigation into the performance impact of various burst assembly strategies on an OBS edge node¿s mean buffer length is conducted. Realistic traffic characteristics are considered based on the analysis of the OC-192 backbone traffic traces. In addition the effect of burstiness in the small time scales on mean assembly time and burst size distribution is investigated. A new Dynamic OBS Offset Allocation Protocol is devised and favourable comparisons are carried out between the proposed OBS protocol and the Just Enough Time (JET) protocol, in terms of mean queue length, blocking and throughput. Finally the research focuses on simulation methodologies employed throughout the thesis using the Graphics Processing Unit (GPU) on a commercial NVidia GeForce 8800 GTX, which was initially designed for gaming computers. Parallel generators of Optical Bursts are implemented and simulated in ¿Compute Unified Device Architecture¿ (CUDA) and compared with simulations run on general-purpose CPU proving the GPU to be a cost-effective platform which can significantly speed-up calculations in order to make simulations of more complex and demanding networks easier to develop.