An Advance Distributed Control Design for Wide-Area Power System Stability

The development of control of a power system that supply electricity is a major concern in the world. Some trends have led to power systems becoming overstated including the rapid growth in the demand for electrical power, the increasing penetration of the system from renewable energy, and uncertainties in power schedules and transfers. To deal with these challenges, power control has to overcome several structural hurdles, a major one of which is dealing with the high dimensionality of the system. Dimensionality reduction of the controller structure produces effective control signals with reduced computational load. In most of the existing studies, the topology of the control and communication structure is known prior to synthesis, and the design of distributed control is performed subject to this particular structure. However, in this thesis we present an advanced model of design for distributed control in which the control systems and their communication structure are designed simultaneously. In such cases, a structure optimization problem is solved involving the incorporation of communication constraints that will punish any communication complexity in the interconnection and thus will be topology dependent. This structure optimization problem can be formulated in the context of Linear Matrix Inequalities and l1-minimization. Interconnected power systems typically show multiple dominant inter-area low-frequency oscillations which lead to widespread blackouts. In this thesis, the specific goal of stability control is to suppress these inter-area oscillations. Simulation results on large-scale power system are presented to show how an optimal structure of distributed control would be designed. Then, this structure is compared with fixed control structures, a completely decentralized control structure and a centralized control structure

Characteristics of red light running violations in urban areas in Tabuk, Kingdom of Saudi Arabia

AbstractThis paper aims to assess the characteristics of red light violations in Tabuk city of the Kingdom of Saudi Arabia. The paper also analyzes the effect of intersection characteristics, such as geometric design, control system and location, on number of violations. Data on traffic characteristics and violations, intersection geometric design (road width, number of lanes, speed) were collected at 38 intersections in Tabuk using video cameras. Statistical analysis reveals that number of approaches, speed, road width, speed on cross road, and width of cross road significantly affects red light violation. Regression analysis implies that road width, red time and speed are the most important factors affecting red light violation

A software-defined survivability approach for wireless sensor networks in future internet of the things

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonThe Internet of the Things (IoT) is evolving rapidly, and its significant impacts are expected to affect many application domains. Challenges in areas that humans have been striving to understand, measure, or predict—such as wildlife, healthcare, or environmental hazards—are likely to be addressed by the time IoT emerges. The underlying elements of IoT are wireless sensor networks (WSNs), which consist of a large number of sensor nodes. In the IoT sphere, sensor nodes represent tangible objects—Things—that monitor changes, collect information, and eventually send it through the Internet to a recipient party. Inherently, however, a wireless sensor node relies on limited computational resources with a limited power source. These undesirable qualities result in a low level of dependability. This research explores the viability of applying the unfolding network programmability concepts to overcome survivability obstacles in WSNs and the IoT. In particular, it examines the viability of software-defined networking (SDN) in network lifetime maximisation, failure detection, and failure recovery problems in WSNs. Software-defined networking is a new network programmability concept that separates the traditionally-tied control and data planes. It offloads the route computations and management from network devices to a logically centralised controller. This separation directly leads to better allocation of computational resources for the network nodes and allows endless orchestration possibilities for the controller. This thesis proposes an SDN-based solution to increase the survivability and resilience of WSN environments. Following an approach that conforms with the centralised nature of SDN environments and considers the limited resources of the WSN. A routing algorithm based on A-star was developed for WSNs, then deployed within an SDN environment to maximise the network lifetime. Apart from finding the path with the lowest energy burden, the algorithm offloads most of the control traffic from sensor nodes to the controller. This algorithm resulted in improved resource utilisation among the nodes due to plane decoupling. Additionally, it increased the lifetime of the network by 22.6% compared to the widely explored LEACH protocol. This thesis also investigates different failure detection and recovery practices in the SDN architecture. The simulation results show that adopting bidirectional forwarding detection (BFD) with the asynchronous echo mode for WSN in an SDN environment reduces control traffic for failure detection to between 27% and 48%. The thesis also evaluates the performance of multiple recovery approaches when adopting the premises of SDN. The simulation results indicate that path protection, using group tables from the OpenFlow protocol, has a recovery time up to eight times shorter than the restoration time. The results of the study reveal that using protection as a failure recovery technique significantly reduces control traffic overhead

Structural changes in the eye lens during accommodation

Aim: The main aim of this thesis was to investigate the changes in the lens crystallin molecular spacing and ordering, the lens suture confluence area, and the lens fibre widths, during the accommodation. Methods: The molecular spacing and ordering of crystallin proteins were analysed using small angle X-ray scattering (SAXS) in Atlantic salmon, European ‎squid and porcine lenses, and additionally in stretched and unstretched porcine lenses. Confocal microscopy was used to image anterior and posterior lenses to quantify changes in the lens suture confluence areas and lens fibre widths. In serial cryosections of porcine lenses, accommodative changes in lens fibre widths were analysed in both the nucleus and cortex. Results: The molecular spacing of crystallins within the porcine lens nucleus was significantly less than in the Atlantic salmon and European ‎squid lenses. As a case in point, the Bragg spacing in the porcine nucleus area, at 1mm along the horizontal meridian, ‎decreased from 18.9 ± 0.3 nm to 15.9 ±0.3 nm.‎ Furthermore, significant accommodative changes in the average spacing between crystallin proteins in all vertical and horizontal meridians (p < 0.05) were determined. For instance, at the 1 mm vertical meridian, Bragg spacing in an unstretched lens increased from 16.6 ± 0.6 nm to 20.9 ± 2.8 nm in a stretched lens. The suture confluence area also changed following stretch at some depths. A significant increase in lens fibre widths in stretched lenses was observed in the nucleus (43.3 ± 10.2m versus 47.1 ± 8.6m, p = 0.001), the anterior cortex (67.4 ± 16.8m versus 72.9 ± 17.8m, p = 0.000), and the equatorial cortex (90.5 ± 11.2m versus 96.5 ± 11.9m, p = 0.002). However, a significant reduction in the posterior cortical lens fibre widths (69.3 ± 12.4m versus 59.6 ± 9.4m, p = 0.0000) in stretched lenses. Conclusion: The accommodation, as characterised in a porcine model, involves significant structural changes within lens crystallins and fibre widths. To the researcher’s knowledge, the novel data is provided herein. This study contributes to future research in this area by offering enhanced fixation protocols that preserve lens shape, in both accommodated and unaccommodated state, particularly important for 2D SAXS grid scans and microscopy-based analyses

Three-dimensional bioprinting in ophthalmic care

Three-dimensional (3D) bioprinting is widely used in ophthalmic clinic, including in diagnosis, surgery, prosthetics, medications, drug development and delivery, and medical education. Articles published in 2011–2022 into bioinks, printing technologies, and bioprinting applications in ophthalmology were reviewed and the strengths and limitations of bioprinting in ophthalmology highlighted. The review highlighted the trade-offs of printing technologies and bioinks in respect to, among others, material type cost, throughput, gelation technique, cell density, cell viability, resolution, and printing speed. There is already widespread ophthalmological application of bioprinting outside clinical settings, including in educational modelling, retinal imaging/visualization techniques and drug design/testing. In clinical settings, bioprinting has already found application in pre-operatory planning. Even so, the findings showed that even with its immense promise, actual translation to clinical applications remains distant, but relatively closer for the corneal (except stromal) tissues, epithelium, endothelium, and conjunctiva, than it was for the retina. This review similarly reflected on the critical on the technical, practical, ethical, and cost barrier to rapid progress of bioprinting in ophthalmology, including accessibility to the most sophisticated bioprinting technologies, choice, and suitability of bioinks, tissue viability and storage conditions. The extant research is encouraging, but more work is clearly required for the push towards clinical translation of research

The application of family law in the Bahraini Courts and the need for Codification

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Household travel and tour-based behaviour: a case study from Saudi Arabia

The present study utilises the activity-based approach to investigate the nature and determinants of travel behaviour, and to reach a better understanding of travel complexity within households in an Islamic cultural environment. The main objectives of this study are, firstly to describe and explain the variation of behaviour between a sample of Saudi households and, secondly, to identify the likely response to specific transport policies. Results suggest that household head attributes (occupation, education and income), household socio-economic characteristics (car ownership, availability of a chauffeur, number of female students, number of females in employment and household size), and neighbourhood characteristics (density, accessibility to work) significantly influenced the choice of work tour type. The usefulness of applying tour-based analysis and its strength in showing interactions between household members' activities were confirmed in this study. Tour-based models revealed that Saudi households' travel activities were highly dependent on the household head, who is mainly responsible for serving household members' travel needs. In-depth interviews showed concerns about children's safety and security, lack of public and, in particular, school transport, ignorance of female travel needs, and car oriented neighbourhood design were main reasons for the high dependency on the car and its role as the dominant travel mode within Saudi cities. Interviewees were presented with five transport related policies to investigate their likely impact on households' travel behaviour. Interviewees agreed that the proposed policies would decrease car dependency and increase the travel independence of household members. Change in travel behaviour, in response to proposed policies, as identified by interviewees included decreased travel complexity (simpler tours), change in tour mode (more walking and public transport tours), and change in tour time. The study estimated a reduction in car trips generated by households as a result of introducing policies aimed to shift dependent groups (i.e. children and females) towards independence through walking and use of public transpor

Acute disseminated encephalomyelitis: a call to the clinicians for keeping this rare condition on clinical radar

Acute disseminated encephalomyelitis is a rare disease of central nervous system, which can present with a variety of clinical manifestations. That is why first attack of ADEM, in particular remains a diagnostic puzzle. Early anticipation and diagnosis is important for better outcomes. We present a case of acute disseminated encephalomyelitis which initially had atypical clinical features with cough, expectoration, fever and later manifested strange neurological features, diagnosed to be a case of acute disseminated encephalomyelitis based on radio-imaging

Woodcutting Activities in Tabuk Region (Saudi Arabia): Assessment of Conservation Knowledge

The present study aims to investigate the effect of different social factors on the woodcutting frequency in Tabuk Region. A total of 100 people participated in this study by answering the questionnaire questions. The conservation knowledge of the participants was also assessed through 4 questions (Yes or No). The final score of the conservation knowledge assessment is 4. The present study findings showed that most of people like to cut the wood for heating during winter and fall seasons. The frequency of woodcutting in Tabuk Region was once a month. Among the social factors involved in this study, education showed negative and significant relationship with the number of logging times. However, age had positive relationship with the number of logging times. The most favourbale species to be cut and used for heating and cooking in Tabuk are; Acacia tortilis, Acacia ehrenbergiana, Retama reaetam and Calligonum comosum. For the assessment of the public conservation knowledge, it was found that most of participants had moderate to good conservation knowledge as most of them answered 3 questions correctly out of 4. The conservation knowledge showed to be affected positively by education level and negatively by the number of family members. In conclusion, it was found that there is remarkable woodcutting stress on wild plants in Tabuk Region and immediate and effective actions should be performe