• Daisaku Ikeda's philosophy of peace: Human revolution, dialogue and global civilization.

      van den Dungen, Peter; Urbain, Olivier (University of BradfordDepartment of Peace Studies, 2009-08-24)
      Daisaku Ikeda is the Buddhist leader of one of the most visible religious movements today, the Soka Gakkai International (SGI). In this thesis, the main research question concerns the peace philosophy of Ikeda and its contribution to peace theory. Daisaku Ikeda and the SGI have been the subject of several scholarly studies in the fields of religious history and sociology. The focus of this research is on the significance of Ikeda's contributions in the field of peace studies, where his work has not yet been the subject of systematic investigation. It is argued that the originality of Ikeda's philosophy of peace resides in two main elements. First, the starting point is consistently human life and its potential for peace and happiness, not the omnipresence of conflict. Second, he offers a coherent system linking the individual, dialogical and global levels, which can be represented as a triangle made of three conceptual frameworks, that of Humanistic Psychology (Human Revolution), Communicative Rationality (Dialogue) and Cosmopolitan Democracy (Global Civilization). It is also argued that while being inspired by Ikeda's Buddhist spirituality and his loyalty to his mentor Josei Toda, this secular humanist approach to peace offers an effective and original way for all people to participate in the construction of a better world, regardless of their religious or ideological affiliation, social background or cultural practices.
    • Data-driven flight path rerouting during adverse weather: Design and development of a passenger-centric model and framework for alternative flight path generation using nature inspired techniques

      Hu, Yim Fun; Li, Jian-Ping; Pillai, Prashant; Ayo, Babatope S.
      A major factor that negatively impacts flight operations globally is adverse weather. To reduce the impact of adverse weather, avoidance procedures such as finding an alternative flight path can usually be carried out. However, such procedures usually introduce extra costs such as flight delay. Hence, there exists a need for alternative flight paths that efficiently avoid adverse weather regions while minimising costs. Existing weather avoidance methods used techniques, such as Dijkstra’s and artificial potential field algorithms that do not scale adequately and have poor real time performance. They do not adequately consider the impact of weather and its avoidance on passengers. The contributions of this work include a new development of an improved integrated model for weather avoidance, that addressed the impact of weather on passengers by defining a corresponding cost metric. The model simultaneously considered other costs such as flight delay and fuel burn costs. A genetic algorithm (GA)-based rerouting technique that generates optimised alternative flight paths was proposed. The technique used a modified mutation strategy to improve global search. A discrete firefly algorithm-based rerouting method was also developed to improve rerouting efficiency. A data framework and simulation platform that integrated aeronautical, weather and flight data into the avoidance process was developed. Results show that the developed algorithms and model produced flight paths that had lower total costs compared with existing techniques. The proposed algorithms had adequate rerouting performance in complex airspace scenarios. The developed system also adequately avoided the paths of multiple aircraft in the considered airspace.
    • Database Metadata Requirements for Automated Web Development. A case study using PHP.

      Ridley, Mick J.; Mgheder, Mohamed A. (University of BradfordDepartment of Computing, 2011-06-22)
      The Web has come a long way. It started as a distributed document repository and quickly became the spring board for a new type of application. Propped on top of the original HTML+HTTP architecture, this new application platform shifted the way the architecture was used so that commands and functionality were embedded in the form data of Web requests rather than in the HTTP command conveying the request. This approach enabled Web requests to convey any type of data, not just document operations. This is occurring because the Web provides such a powerful platform on which to create applications. This is occurring because web development methods are still evolving toward the structure and stability required taking on this enormous new role. As the needs of developers change, certain themes that arise more frequently than others become embedded into new environments to support those needs. Until recently, Web application programming has largely been done with a set of keywords and metaphors developed long before the Web became a popular place to program. APIs have been developed to support Web specific features, but they are no replacement for fundamental changes in the programming environment itself. The growth of Web applications requires a new type of programming designed specifically for the needs of the Web. This thesis aims to contribute towards the development of an abstract framework to generate abstract and dynamic Web user interfaces that are not developed to a specific platform. To meet this aim, this thesis suggests a general implementation of a prototype system that uses the information in database metadata in conjunction with PHP. Database metadata is richer in providing the information needed to build dynamic user interfaces. This thesis uses PHP and the abstract library ADOdb to provide us with a generalised database metadata based prototype. PHP does not have any restrictions on accessing and extracting database metadata from numerous database management systems. As a result, PHP and relational database were used to build the proposed framework. Additionally, ADOdb was used to link the two mentioned technologies. The implemented framework in this thesis demonstrates that it is possible to generate different automatic Web entry forms that are not specific at any platform.
    • Death, disability, and diversity: An investigation of physical impairment and differential mortuary treatment in Anglo-Saxon England

      Buckberry, Jo; Croucher, Karina T.; Bohling, Solange N. (University of BradfordSchool of Archaeological and Forensic Sciences, 2020)
      Until recently, individuals with physical impairment have been overlooked within the field of archaeology due to the controversy surrounding the topics of disability and care in the past. The current research adds to the growing body of archaeological disability studies with an exploration of physical impairment and the possibility of disability-related care in Anglo-Saxon England (5th-11th centuries AD), utilising palaeopathological, funerary, and documentary analyses. Palaeopathological analysis of 86 individuals with physical impairment from 19 Anglo-Saxon cemetery populations (nine early, five middle, and five later) was performed, and the possibility of disability-related care was explored for several individuals. The mortuary treatment data (e.g. grave orientation, body position, grave good inclusion) was gathered for the entire burial population at each site (N=3,646), and the funerary treatment of the individuals with and without physical impairment was compared statistically and qualitatively, both within and between the Anglo-Saxon periods. No obvious mortuary differentiation of individuals with physical impairment was observed, although several patterns were noted. In three early Anglo-Saxon cemeteries, spatial association between individuals with physical impairment, non-adults, and females was observed. Early Anglo-Saxon individuals with physical impairment were more frequently buried in marginal locations, and two such individuals were buried in isolation. In the middle and later Anglo-Saxon periods, the funerary treatment of individuals with physical impairment became less variable, they were less frequently buried in marginal locations, and at three middle Anglo-Saxon cemeteries, they were buried in association with socially significant features in the cemetery landscape. The provision of care to ensure survival was not necessary for a majority of the individuals with physical impairment, but several individuals (lower limb paralysis, mental impairment) may have received regular, long-term care. This research proposes that the decreasing variability of mortuary treatment of individuals with physical impairment observed throughout the Anglo-Saxon period suggests that more variable attitudes about disability existed both within and between early Anglo-Saxon communities, while the political, social, and religious unification starting in the middle Anglo-Saxon period may have led to the development of more standardised perceptions of disability in later Anglo-Saxon England.
    • Debating Islamism, modernity and the West in Turkey. The role of the Welfare Party

      Gallagher, Tom G.P.; Russell, John; Dinc, Cengiz (University of BradfordDepartment of Languages and European Studies, 2010-06-17)
      This study focuses on the Welfare Party elite's conceptualisation of modernity during the party's last 4-5 years before its closure in 1998. Since the party was the most important Islamist organisation in Turkey. it was at an important point of interaction between Islamism and modernity. The study tries to determine the significance of the WP discourse on key modernisation issues by answering such questions as how the WP elite conceptualised modernity; how this conceptualisation was formulated, constructed and what was modernity's relationship with the West in their view. It argues that, the WP elite had a distinct (Islamist) understanding of modernity which, despite its differences in its approach to some basic issues (e. g. secularism) overall remained within modernity by sharing most of its major characteristics. The WP elite, similar to many other Islamist movements, advocated a more Islamic (less secular and less Westernising) route to modernity; and they could not be considered as anti-modernists. The study contributes towards a better understanding of the critical role that a version of Islamism plays in Turkey's politics and process of modernisation and provides insights about the impact of Western modernity on the sizeable Islamist section. The study employs important concepts such as secularisation, nationalism, the modern state, economic development (science, technology, industrialisation), capitalism and democracy as important components of modernity. (It also provides a general analysis of Islamism in the Middle East vis-ä-vis modernity through these concepts). An analysis of the views of the WP elite with regard to these concepts and processes serves to better understanding the Islamist stance towards the particular path of modernisation in Turkey, modernity in general, and also the West.
    • Decentralisation and the Management of Ethnic Conflict: A Case Study of the Republic of Macedonia.

      Pugh, Michael C.; Lyon, Aisling (University of BradfordDepartment of Peace Studies, 2013-11-21)
      This thesis considers the extent to which decentralisation in the Republic of Macedonia between 2005 and 2012 has been effective in reducing ethnic inequalities that exacerbate social divisions and can lead to conflict. Guided by the concept of horizontal inequalities, it identifies the factors which influenced the decision to devolve responsibilities to the municipalities after 2001. It examines the particular institutional design that Macedonian decentralisation took, and demonstrates how its use of local power-sharing mechanisms was intended to address the concerns of the Albanian and Macedonian communities simultaneously. This thesis takes an integrative approach to studying the political, administrative, and fiscal dimensions of decentralisation¿s implementation, and considers whether the reform has indeed contributed to the reduction of inequalities between Macedonia¿s ethnic groups. Where decentralisation¿s potential has not been reached, obstacles to its successful implementation are identified. While decentralisation alone may be unable to address all of the grievances raised by the Albanian community prior to 2001, this thesis argues that the reform has the potential to address many of the horizontal inequalities that were responsible for raising inter-ethnic tensions during the 1990s. However, decentralisation in Macedonia between 2005 and 2012 has only been partial, and advances in the administrative and political aspects of the reform have been undermined by limited progress in its fiscal dimension. Attempts to solve self-determination conflicts through decentralisation will fail if local self-governance exists only in form but not in substance.
    • Decomposition of general queueing network models. An investigation into the implementation of hierarchical decomposition schemes of general closed queueing network models using the principle of minimum relative entropy subject to fully decomposable constraints.

      Kouvatsos, Demetres D.; Tomaras, Panagiotis J. (University of BradfordPostgraduate School of Studies in Computing, 2010-02-08)
      Decomposition methods based on the hierarchical partitioning of the state space of queueing network models offer powerful evaluation tools for the performance analysis of computer systems and communication networks. These methods being conventionally implemented capture the exact solution of separable queueing network models but their credibility differs when applied to general queueing networks. This thesis provides a universal information theoretic framework for the implementation of hierarchical decomposition schemes, based on the principle of minimum relative entropy given fully decomposable subset and aggregate utilization, mean queue length and flow-balance constraints. This principle is used, in conjuction with asymptotic connections to infinite capacity queues, to derive new closed form approximations for the conditional and marginal state probabilities of general queueing network models. The minimum relative entropy solutions are implemented iteratively at each decomposition level involving the generalized exponential (GE) distributional model in approximating the general service and asymptotic flow processes in the network. It is shown that the minimum relative entropy joint state probability, subject to mean queue length and flow-balance constraints, is identical to the exact product-form solution obtained as if the network was separable. An investigation into the effect of different couplings of the resource units on the relative accuracy of the approximation is carried out, based on an extensive experimentation. The credibility of the method is demonstrated with some illustrative examples involving first-come-first-served general queueing networks with single and multiple servers and favourable comparisons against exact solutions and other approximations are made.
    • 'Defragmenting the portrait': Catalina Clara Ramírez De Guzman, extremadura's No Conocida Señora of the golden age. A critical multidisciplinary reappraisal of the work of Catalina Clara Ramírez de Guzmán (Llerena, 1618-c.1684)

      White, Anne M.; Price, Munro; Gregory, James R.T.E.; McLaughlin, Karl P. (University of BradfordDepartment of Languages and European Studies, 2010-09-01)
      Modern critical works on the seventeenth-century Extremaduran author Catalina Clara Ramírez de Guzmán are sparse, with the exception of recent interest manifested by a small group of feminist scholars in the United States. Apart from intermittent mentions of her poetry, she is virtually unknown among British Hispanists. This thesis seeks to fill many existing gaps in knowledge on her by providing a broader critical assessment of her surviving poetry than has been available thus far, particularly by situating it and its author within their historical, literary and social contexts and drawing thematic and stylistic analogies with works by other authors, male and female. Part I will concentrate primarily on historical aspects. It will establish the reputation enjoyed by the poet in her day and review references to her work in modern critical literature. It will also provide a detailed reconstruction of the poet¿s family antecedents and discuss the evidence of a literary community in her home city during the period in which she was active as a writer. Part II will focus on the poetry itself, specifically a consideration of the thematic content of a broad representative selection of Ramírez de Guzmán¿s verses, which were not published until nearly two centuries after her death, and an examination of her interaction with the genres of occasional verse, verse portraiture and burlesque and satirical poetry, all of which will be discussed against the background of their respective traditions.
    • Delay to diagnosis and specialist consultation following anterior cruciate ligament injury: A study investigating the nature of, and factors associated with, pathway delay

      Hardy, Maryann L.; Scally, Andy J.; Ayre, Colin A. (University of BradfordFaculty of Health Studies, 2016)
      Background: Historically the identification of ACL injuries upon initial presentation is low and considerable diagnostic delays have been reported. However, specific evidence on the individual elements of, and factors which influence delay, is lacking. Aims: The overarching aim was to provide a comprehensive picture of delay to diagnosis and specialist consultation, including factors which influence delay. An additional aim was to determine whether the approach to examining acute knee injuries varied as a consequence of varying patient presentation or experience of the assessing clinician. Methods: Study 1: Cross -sectional survey. Study 2: Non-participant direct observation methodology. Results: Data from 194 patients were analysed in the survey. Only 15.5% of patients were given a correct diagnosis of ACL rupture at the initial consultation. Median delay to diagnosis was 67.5 days (IQR= 15 to 178 days) and specialist consultation 108 days (IQR= 38 to 292 days). The factors most influential on delay were whether a follow-up appointment was arranged after attending A&E, whether the site of attendance operated an acute knee clinic and whether MRI was performed. The direct observation study showed wide variation in approach to injury assessment. Specialist clinicians performed the most comprehensive examination. A&E clinicians were more likely to assess for bony, neurovascular and gross tendon injuries as opposed to ligamentous or meniscal injury. Conclusions: The diagnostic rate of ACL injury at initial presentation remains low. Considerable delays to diagnosis and specialist consultation are apparent following ACL injury, the majority of which is attributable to health system delay.
    • A Dementia Care Mapping (DCM) data warehouse as a resource for improving the quality of dementia care. Exploring requirements for secondary use of DCM data using a user-driven approach and discussing their implications for a data warehouse

      Neagu, Daniel; Small, Neil A.; Khalid, Shehla (University of BradfordFaculty of Health Studies, 2016)
      The secondary use of Dementia Care Mapping (DCM) data, if that data were held in a data warehouse, could contribute to global efforts in monitoring and improving dementia care quality. This qualitative study identifies requirements for the secondary use of DCM data within a data warehouse using a user-driven approach. The thesis critically analyses various technical methodologies and then argues the use and further demonstrates the applicability of a modified grounded theory as a user-driven methodology for a data warehouse. Interviews were conducted with 29 DCM researchers, trainers and practitioners in three phases. 19 interviews were face to face with the others on Skype and telephone with an average length of individual interview 45-60 minutes. The interview data was systematically analysed using open, axial and selective coding techniques and constant comparison methods. The study data highlighted benchmarking, mappers’ support and research as three perceived potential secondary uses of DCM data within a data warehouse. DCM researchers identified concerns regarding the quality and security of DCM data for secondary uses, which led to identifying the requirements for additional provenance, ethical and contextual data to be included in a warehouse alongside DCM data to meet requirements for secondary uses of this data for research. The study data was also used to extrapolate three main factors such as an individual mapper, the organization and an electronic data management that can influence the quality and availability of DCM data for secondary uses. The study makes further recommendations for designing a future DCM data warehouse.
    • Design and analysis of Discrete Cosine Transform-based watermarking algorithms for digital images. Development and evaluation of blind Discrete Cosine Transform-based watermarking algorithms for copyright protection of digital images using handwritten signatures and mobile phone numbers.

      Qahwaji, Rami S.R.; Al-Ahmad, Hussain; Al-Gindy, Ahmed M.N. (University of BradfordSchool of Computing, Informatics and Media, 2012-06-22)
      This thesis deals with the development and evaluation of blind discrete cosine transform-based watermarking algorithms for copyright protection of digital still images using handwritten signatures and mobile phone numbers. The new algorithms take into account the perceptual capacity of each low frequency coefficients inside the Discrete Cosine Transform (DCT) blocks before embedding the watermark information. They are suitable for grey-scale and colour images. Handwritten signatures are used instead of pseudo random numbers. The watermark is inserted in the green channel of the RGB colour images and the luminance channel of the YCrCb images. Mobile phone numbers are used as watermarks for images captured by mobile phone cameras. The information is embedded multiple-times and a shuffling scheme is applied to ensure that no spatial correlation exists between the original host image and the multiple watermark copies. Multiple embedding will increase the robustness of the watermark against attacks since each watermark will be individually reconstructed and verified before applying an averaging process. The averaging process has managed to reduce the amount of errors of the extracted information. The developed watermarking methods are shown to be robust against JPEG compression, removal attack, additive noise, cropping, scaling, small degrees of rotation, affine, contrast enhancements, low-pass, median filtering and Stirmark attacks. The algorithms have been examined using a library of approximately 40 colour images of size 512 512 with 24 bits per pixel and their grey-scale versions. Several evaluation techniques were used in the experiment with different watermarking strengths and different signature sizes. These include the peak signal to noise ratio, normalized correlation and structural similarity index measurements. The performance of the proposed algorithms has been compared to other algorithms and better invisibility qualities with stronger robustness have been achieved.
    • Design and analysis of energy-efficient media access control protocols in wireless sensor networks. Design and analysis of MAC layer protocols using low duty cycle technique to improve energy efficient and enhance communication performance in wireless sensor networks.

      Awan, Irfan U.; Ammar, Ibrahim A.M. (University of BradfordSchool of Electrical Engineering and Computer Science, 2015-06-17)
      Wireless sensor network (WSN) technology has gained significant importance due to its potential support for a wide range of applications. Most of the WSN applications consist of a large numbers of distributed nodes that work together to achieve common objects. Running a large number of nodes requires an efficient mechanism to bring them all together in order to form a multi-hop wireless network that can accomplish some specific tasks. Even with recent developments made in WSN technology, numbers of important challenges still stand as vulnerabilities for WSNs, including energy waste sources, synchronisation leaks, low network capacity and self-configuration difficulties. However, energy efficiency remains the priority challenging problem due to the scarce energy resources available in sensor nodes. These concerns are managed by medium access control (MAC) layer protocols. MAC protocols designed specifically for WSN have an additional responsibility of managing radio activity to conserve energy in addition to the traditional functions. This thesis presents advanced research work carried out in the context of saving energy whilst achieving the desired network performance. Firstly the thesis contributes by proposing Overlapped Schedules for MAC layer, in which the schedules of the neighbour clusters are overlapped by introducing a small shift time between them, aiming to compensate the synchronisation errors. Secondly, this thesis proposed a modified architecture derived from S-MAC protocol which significantly supports higher traffic levels whilst achieving better energy efficiency. This is achieved by applying a parallel transmission concept on the communicating nodes. As a result, the overall efficiency of the channel contention mechanism increases and leads to higher throughput with lower energy consumption. Finally, this thesis proposed the use of the Adaptive scheme on Border Nodes to increase the power efficiency of the system under light traffic load conditions. The scheme focuses on saving energy by forcing the network border nodes to go off when not needed. These three contributions minimise the contention window period whilst maximising the capacity of the available channel, which as a result increase network performance in terms of energy efficiency, throughput and latency. The proposed system is shown to be backwards compatible and able to satisfy both traditional and advanced applications. The new MAC protocol has been implemented and evaluated using NS-2 simulator, under different traffic loads and varying duty cycle values. Results have shown that the proposed solutions are able to significantly enhance the performance of WSNs by improving the energy efficiency, increasing the system throughput and reducing the communication delay.
    • The design and development of a knowledge-based lean six sigma maintenance system for sustainable buildings. The design and development of a hybrid Knowledge-based (KB)/Gauging Absence of Pre-requisites (GAP)/Analytic Hierarchy Process (AHP) model for implementing lean six sigma maintenance system in sustainable buildings' environment

      Khan, M. Khurshid; Munive-Hernandez, J. Eduardo; Al Dairi, Jasim S.S. (University of BradfordFaculty of Engineering and Informatics, 2017)
      The complexity of sustainable building maintenance environment requires managers to define and implement appropriate quality benchmark system suitable for this function. Lean Six Sigma (LSS) is one of the most effective process improvement and optimization philosophy that maintenance organisations can implement in their environment. However, literature review has shown that 90% of failures in LSS implementations are due to lack of readiness to change, the unawareness of the required benchmark organisation capabilities, and improper control of priorities. The contribution of the current research approach is in developing a hybrid Knowledge-Based (KB)/GAP/AHP System, consisting of three stages (Planning, Designing and Implementation) and containing over 2500 KB rules. The KB System can assist the decision-makers in identifying the obstacles behind the organisation readiness to change into a benchmark LSS maintenance environment. Thus the KB System will be used to achieve benchmark standards by determining the gap existing between the current environment and the benchmark goal, and then suggest a detailed plan to overcome these hurdles in a prioritised and structured manner, thus achieving cost benefits. To ensure its consistency and reliability, the KB System was validated in three Oman-based maintenance organisations, and one published case study for a UK-based organisation. The results from the validation were positive with the System output suggesting list of top priorities and action plans for achieving benchmark LSS standards for these organisations. The research concludes that the developed KB System is a consistent and reliable methodology for assisting decision-makers in designing, planning, and implementing LSS for benchmark sustainable building maintenance.
    • Design and development of a low cost heart best monitor device using finger photoplethysmography technique :|bcircuit design and fabrication of a non-invasive heart beat monitoring device that employs reflectance and transmission mode photoplethysmography using parallel port interface and microcontroller PIC16F84A.

      Youseffi, Mansour; Ramli, Nur Ilyani Binti (University of BradfordSchool of Engineering, Design and Technology, 2015-06-23)
      A low cost Heart Beat Monitoring device (HBMD) for detecting heart beat in beats per minute is presented in this thesis. An optical technique called “Photoplethysmography” is utilized by attaching to the base of the finger for monitoring beat to beat pulsation. Two major design issues addressed in this research is to achieve a strong and accurate PPG signal and simultaneously minimizing physiological artefacts and interference. In order to achieve the aim and objectives of the research, this thesis thoroughly explores two new signal conditioning hardware designs. Firstly is the design and fabrication of a low cost reflectance mode PPG heart monitor using parallel port interfacing and secondly are the design and development of a portable transmission mode PPG heart monitor using microcontroller PIC16F84A and PIC16F87. Both PPG heart monitor design is divided into three phases. First is the detection of weak pulses through the fingertip. The PPG signal is then amplified, filtered and digitized by the signal processing unit. Finally the heart rate is calculated, analyzed and displayed on the computer using parallel port interface and on the liquid crystal display using microcontroller PIC16F87. A comprehensive circuit design and analysis work was implemented verified by Proteus VSM circuit simulations and laboratory experiments. Data is presented from the method comparison study in which heart rates measured with the reflectance mode PPG and portable transmission mode PPG heart monitor were compared with those measured with standard techniques on 13 human subjects. Benchmarking tests with approved pulse oximeter and blood pressure monitor Omron M6 reveals that the PPG heart monitor is comparable to those devices in displaying the heart rate. It is also verified through experiments that both PPG heart monitor design fulfill the objectives, including achieving strong and accurate PPG signal, reduction in physiological artefacts and interference and financially low in cost. As the conclusion, the current version of the reflectance mode PPG and portable transmission mode PPG heart monitor successfully measure heart rates fast and reliably in most subjects in different body position. The PPG heart monitor proposed avoid the need to apply electrodes or other sensors in the correct position which directly minimizes the preparation time drastically. This makes the PPG heart monitor more attractive for heart monitoring purpose and its advantage should be explored further.
    • Design and Evaluation of Security Mechanism for Routing in MANETs. Elliptic Curve Diffie-Hellman cryptography mechanism to secure Dynamic Source Routing protocol (DSR) in Mobile Ad Hoc Network (MANET).

      Awan, Irfan U.; Almotiri, Sultan H. (University of BradfordSchool of Computing, Informatics and Media, 2013-11-27)
      Ensuring trustworthiness through mobile nodes is a serious issue. Indeed, securing the routing protocols in Mobile Ad Hoc Network (MANET) is of paramount importance. A key exchange cryptography technique is one such protocol. Trust relationship between mobile nodes is essential. Without it, security will be further threatened. The absence of infrastructure and a dynamic topology changing reduce the performance of security and trust in mobile networks. Current proposed security solutions cannot cope with eavesdroppers and misbehaving mobile nodes. Practically, designing a key exchange cryptography system is very challenging. Some key exchanges have been proposed which cause decrease in power, memory and bandwidth and increase in computational processing for each mobile node in the network consequently leading to a high overhead. Some of the trust models have been investigated to calculate the level of trust based on recommendations or reputations. These might be the cause of internal malicious attacks. Our contribution is to provide trustworthy communications among the mobile nodes in the network in order to discourage untrustworthy mobile nodes from participating in the network to gain services. As a result, we have presented an Elliptic Curve Diffie-Hellman key exchange and trust framework mechanism for securing the communication between mobile nodes. Since our proposed model uses a small key and less calculation, it leads to a reduction in memory and bandwidth without compromising on security level. Another advantage of the trust framework model is to detect and eliminate any kind of distrust route that contain any malicious node or suspects its behavior.
    • Design and implementation of adaptive baseband predistorter for OFDM nonlinear transmitter. Simulation and measurement of OFDM transmitter in presence of RF high power amplifier nonlinear distortion and the development of adaptive digital predistorters based on Hammerstein approach.

      Abd-Alhameed, Raed A.; Excell, Peter S.; Ghazaany, Tahereh S. (University of BradfordSchool of Engineering, Design and Technology, 2013-11-20)
      The objective of this research work is to investigate, design and measurement of a digital predistortion linearizer that is able to compensate the dynamic nonlinear distortion of a High Power Amplifier (PA). The effectiveness of the proposed baseband predistorter (PD) on the performance of a WLAN OFDM transmitter utilizing a nonlinear PA with memory effect is observed and discussed. For this purpose, a 10W Class-A/B power amplifier with a gain of 22 dB, operated over the 3.5 GHz frequency band was designed and implemented. The proposed baseband PD is independent of the operating RF frequency and can be used in multiband applications. Its operation is based on the Hammerstein system, taking into account PA memory effect compensation, and demonstrates a noticeable improvement compared to memoryless predistorters. Different types of modelling procedures and linearizers were introduced and investigated, in which accurate behavioural models of Radio Frequency (RF) PAs exhibiting linear and nonlinear memory effects were presented and considered, based on the Wiener approach employing a linear parametric estimation technique. Three new linear methods of parameter estimation were investigated, with the aim of reducing the complexity of the required filtering process in linear memory compensation. Moreover, an improved wiener model is represented to include the nonlinear memory effect in the system. The validity of the PA modelling approaches and predistortion techniques for compensation of nonlinearities of a PA were verified by several tests and measurements. The approaches presented, based on the Wiener system, have the capacity to deal with the existing trade-off between accuracy and convergence speed compared to more computationally complex behavioural modelling algorithms considering memory effects, such as those based on Volterra series and Neural Networks. In addition, nonlinear and linear crosstalks introduced by the power amplifier nonlinear behaviour and antennas mutual coupling due to the compact size of a MIMO OFDM transmitter have been investigated.
    • Design and implementation of band rejected antennas using adaptive surface meshing and genetic algorithms methods. Simulation and measurement of microstrip antennas with the ability of harmonic rejection for wireless and mobile applications including the antenna design optimisation using genetic algorithms.

      Abd-Alhameed, Raed A.; McEwan, Neil J.; Bin-Melha, Mohammed S. (University of BradfordSchool of Engineering, Design and Technology, 2014-05-30)
      With the advances in wireless communication systems, antennas with different shapes and design have achieved great demand and are desirable for many uses such as personal communication systems, and other applications involving wireless communication. This has resulted in different shapes and types of antenna design in order to achieve different antenna characteristic. One attractive approach to the design of antennas is to suppress or attenuate harmonic contents due to the non-linear operation of the Radio Frequency (RF) front end. The objectives of this work were to investigate, design and implement antennas for harmonic suppression with the aid of a genetic algorithm (GA). Several microstrip patch antennas were designed to operate at frequencies 1.0, 1.8 and 2.4 GHz respectively. The microstrip patch antenna with stub tuned microstrip lines was also employed at 1.0 and 1.8 GHz to meet the design objectives. A new sensing patch technique is introduced and applied in order to find the accepted power at harmonic frequencies. The evaluation of the measured power accepted at the antenna feed port was done using an electromagnetic (EM) simulator, Ansoft Designer, in terms of current distribution. A two sensors method is presented on one antenna prototype to estimate the accepted power at three frequencies. The computational method is based on an integral equation solver using adaptive surface meshing driven by a genetic algorithm. Several examples are demonstrated, including design of coaxially-fed, air-dielectric patch antennas implanted with shorting and folded walls. The characteristics of the antennas in terms of the impedance responses and far field radiation patterns are discussed. The results in terms of the radiation performance are addressed, and compared to measurements. The presented results of these antennas show a good impedance matching at the fundamental frequency with good suppression achieved at the second and third harmonic frequencies.
    • Design and Implementation of Radio Frequency Power Feeding Networks for Antenna Array Applications: Simulation and Measurements of Multiport, Equal and Unequal, Fixed and Reconfigurable Radio Frequency Power Feeding Networks for Narrow and Ultra-Wideband Applications

      Abd-Alhameed, Raed A.; Ali, Ammar H.A.
      Power dividers are vital components and widely used in radio technology, such as antenna arrays, power amplifiers, multiplexers and mixers. A good example is the well-known Wilkinson power divider with its distinctive feeding network characteristics. A comprehensive review indicated that limited research is carried out in the area of planar multiport and reconfigurable power dividers in terms of the power levels between output ports. The main objectives of this work were to develop a small size power divider, a planer multi-output ports power divider and a power divider with a reconfigurable power division ratio. These power dividers were designed to operate over either an ultra-wideband frequency (3.1-10.6 GHz) or WLAN bands (2.4 or 5.2 GHz). A novel multi-layered topology solved the complexity of interconnecting isolation resistors by introducing an additional layer below the ground layer. The prototype was fabricated and tested to validate the results. The measurements and simulation were in good agreement. Finally, a novel uniplanar power divider with reconfigurable output power level difference was developed. The configurability feature was achieved by tuning the quarter wave transformer using one varactor diode. The power divider was applied to improve a full duplex system cancellation performance at the receiver element caused by interference from in-site transmitting antennas. This study investigated fixed power dividers, multi-output power dividers and reconfigurable power dividers. The measurements validated by the simulation results and applications proved the designed power dividers could be used in practical applications.
    • Design and Implementation of System Components for Radio Frequency Based Asset Tracking Devices to Enhance Location Based Services. Study of angle of arrival techniques, effects of mutual coupling, design of an angle of arrival algorithm, design of a novel miniature reconfigurable antenna optimised for wireless communication systems

      Abd-Alhameed, Raed A.; Noras, James M.; Jones, Steven M.R.; See, Chan H.; Asif, Rameez (University of BradfordFaculty of Engineering and Informatics, 2017)
      The angle of arrival estimation of multiple sources plays a vital role in the field of array signal processing as MIMO systems can be employed at both the transmitter and the receiver end and the system capacity, reliability and throughput can be significantly increased by using array signal processing. Almost all applications require accurate direction of arrival (DOA) estimation to localize the sources of the signals. Another important parameter of localization systems is the array geometry and sensor design which can be application specific and is used to estimate the DOA. In this work, various array geometries and arrival estimation algorithms are studied and then a new scheme for multiple source estimation is proposed and evaluated based on the performance of subspace and non-subspace decomposition methods. The proposed scheme has shown to outperform the conventional Multiple Signal Classification (MUSIC) estimation and Bartlett estimation techniques. The new scheme has a better performance advantage at low and high signal to noise ratio values (SNRs). The research work also studies different array geometries for both single and multiple incident sources and proposes a geometry which is cost effective and efficient for 3, 4, and 5 antenna array elements. This research also considers the shape of the ground plane and its effects on the angle of arrival estimation and in addition it shows how the mutual couplings between the elements effect the overall estimation and how this error can be minimised by using a decoupling matrix. At the end, a novel miniaturised multi element reconfigurable antenna to represent the receiver base station is designed and tested. The antenna radiation patterns in the azimuth angle are almost omni-directional with linear polarisation. The antenna geometry is uniplanar printed logspiral with striplines feeding network and biased components to improve the impedance bandwidth. The antenna provides the benefit of small size, and re-configurability and is very well suited for the asset tracking applications.
    • Design and modelling of beam steering antenna array for mobile and wireless applications using optimisation algorithms. Simulation and measrement of switch and phase shifter for beam steering antenna array by applying reactive loading and time modulated switching techniques, optimised using genetic algorithms and particle swarm methods.

      Abd-Alhameed, Raed A.; Excell, Peter S.; Abusitta, M.M. (University of BradfordSchool of Engineering, Design and Technology, 2013-12-05)
      The objectives of this work were to investigate, design and implement beam steering antenna arrays for mobile and wireless applications using the genetic algorithm (GA) and particle swarm optimisation (PSO) techniques as optimisation design tools. Several antenna designs were implemented and tested: initially, a printed dipole antenna integrated with a duplex RF switch used for mobile base station antenna beam steering was investigated. A coplanar waveguide (CPW) to coplanar strip (CPS) transition was adopted to feed the printed dipole. A novel RF switch circuit, used to control the RF signal fed to the dipole antenna and placed directly before it, was proposed. The measured performance of the RF switch was tested and the results confirmed its viability. Then two hybrid coupled PIN diode phase shifters, using Branchline and Rat-Race ring coupler structures, were designed and tested. The generation of four distinct phase shifts was implemented and studied. The variations of the scattering parameters were found to be realistic, with an acceptable ±2 phase shift tolerance. Next, antenna beam steering was achieved by implementing RF switches with ON or OFF mode functions to excite the radiating elements of the antenna array. The switching control process was implemented using a genetic algorithm (GA) method, subject to scalar and binary genes. Anti-phase feeding of radiating elements was also investigated. A ring antenna array with reflectors was modelled and analysed. An antenna of this type for mobile base stations was designed and simulation results are presented. Following this, a novel concept for simple beam steering using a uniform antenna array operated at 2.4 GHz was designed using GA. The antenna is fed by a single RF input source and the steering elements are reactively tuned by varactor diodes in series with small inductors. The beam-control procedure was derived through the use of a genetic algorithm based on adjusting the required reactance values to obtain the optimum solution as indicated by the cost function. The GA was also initially used as an optimisation tool to derive the antenna design from its specification. Finally, reactive loading and time modulated switching techniques are applied to steer the beam of a circular uniformly spaced antenna array having a source element at its centre. Genetic algorithm (GA) and particle swarm optimisation (PSO) processes calculate the optimal values of reactances loading the parasitic elements, for which the gain can be optimised in a desired direction. For time modulated switching, GA and PSO also determine the optimal on and off times of the parasitic elements for which the difference in currents induced optimises the gain and steering of the beam in a desired direction. These methods were demonstrated by investigating a vertically polarised antenna configuration. A prototype antenna was constructed and experimental results compared with the simulations. Results showed that near optimal solutions for gain optimisation, sidelobe level reduction and beam steering are achievable by utilising these methods. In addition, a simple switching process is employed to steer the beam of a horizontally polarised circular antenna array. A time modulated switching process is applied through Genetic Algorithm optimisation. Several model examples illustrate the radiation beams and the switching time process of each element in the array.