• The 2009 Electronics and Telecommunications Research Seminar Series: 8th Workshop Proceedings.

      Sheriff, Ray E. (University of Bradford, 01/04/2009)
      This is the eighth workshop to be organised under the postgraduate programmes in electrical and electronic engineering (EEE). The workshop concludes the Research Seminar Series, which has provided a platform for disseminating the latest research activities in related technologies through its weekly seminars. The EEE courses cover a broad range of technologies and this is reflected in the variety of topics presented during the workshop. In total, thirty-three papers have been selected for the proceedings, which have been divided into seven sections. The workshop aims to be as close to a `real¿ event as possible. Hence, authors have responded to a Call for Papers with an abstract, prior to the submission of the final paper. This has been a novel experience for many, if not all of the contributors. Clearly, authors have taken up the challenge with enthusiasm, resulting in what promises to be an interesting and informative workshop.
    • The 2011 Electronics and Telecommunications Research Seminar Series: 10th Workshop Proceeedings.

      Sheriff, Ray E. (01/07/2011)
      This is the tenth workshop to be organised under the postgraduate programmes in electrical and electronic engineering (EEE). Over the past ten years, the Research Seminar Series has provided a snapshot of the research agenda. Early Proceedings addressed issues such as third-generation (3G) mobile and GPS satellite navigation, while in this issue, the importance of the green agenda and the influence of broadband mobile communications, smartphones and the World Wide Web are in evidence. In total, forty-five papers have been selected for the Proceedings.
    • Statistical Predictions of Electric Load Profiles in the UK Domestic Buildings.

      Ihbal, Abdel-Baset M.I.; Rajamani, Haile S.; Abd-Alhameed, Raed A.; Jalboub, Mohamed K. (02/12/2010)
      This paper presents a method of generating realistic electricity load profile data for the UK domestic buildings. The domestic space heating and domestic hot water have been excluded in this study. The information and results of previous investigations and works that is available in public reports and statistics have been used as input data when modeling of domestic energy consumption. A questionnaire survey was conducted to find out what occupants do in different times of the day in order to get probabilistic estimates of usage of electrical household. The daily energy demand load profile of each appliance can be predicted using this method. A measured data set is also applied for comparison, and verification. Our analysis shows that the generated load profiles have a good agreement with real data. The daily load profile from individual dwelling to community can be predicted using this method.
    • Weakest Bus Identification Based on Modal Analysis and Singular Value Decomposition Techniques.

      Jalboub, Mohamed K.; Rajamani, Haile S.; Abd-Alhameed, Raed A.; Ihbal, Abdel-Baset M.I. (02/12/2010)
      Voltage instability problems in power system is an important issue that should be taken into consideration during the planning and operation stages of modern power system networks. The system operators always need to know when and where the voltage stability problem can occur in order to apply suitable action to avoid unexpected results. In this paper, a study has been conducted to identify the weakest bus in the power system based on multi-variable control, modal analysis, and Singular Value Decomposition (SVD) techniques for both static and dynamic voltage stability analysis. A typical IEEE 3-machine, 9-bus test power system is used to validate these techniques, for which the test results are presented and discussed.
    • Buried flexible pipes behaviour in unreinforced and reinforced soils under cyclic loading

      Elshesheny, Ahmed; Mohamed, Mostafa H.A.; Sheehan, Therese (201-04)
      Because of the recent worldwide construction expansion, new roads and buildings may be constructed over already existing buried infrastructures e.g. buried utility pipes, leading to excessive loads threatening their stability and longevity. Limited research studies are available to assess the effect of geogrid reinforcing layers inclusion on mitigating the additional stresses on buried structures due to cyclic loadings. In this research, large-scale fully instrumented laboratory tests were conducted to investigate the behaviour of flexible High-Density Polyethylene pipes (HDPE), in unreinforced and geogrid-reinforced sand, subjected to incrementally increasing cyclic loading, e.g. due to different vehicles capacities or load increase with passing time. Results illustrated that deformation rate in pipe and footing, strain generation rate in pipe and reinforcing layers are rapidly increased in the initial loading cycles, in particular during the first 300 cycles, and then the rate of change decreases significantly, as more cycles are applied. In the unreinforced case, increasing the pipe burial depth significantly reduced the generated deformation and strain in the pipe; however, it has a situational effect on the footing settlement, where it increased after pipe burial depth to its diameter ratio (H/D) of 2.5. In reinforced cases, deformation and strain significantly reduced with the increase in pipe burial depth and number of reinforcing layers. Measurement of strain illustrated that strain generated in the lower reinforcing layer is always higher than that recorded in the upper one, regardless pipe burial depth and value of applied load.
    • Guest Editorial: Satellite Systems, Applications and Networking.

      Mitchell, P.D.; Sheriff, Ray E. (The Institution of Engineering and Technology, 03/09/2010)
      Guest Editorial of Special Issue (featuring eight original papers, comprising 133 pages in total). Whilst satellite systems continue to be at the forefront of broadcast communication service provision, they have an increasingly important role to play in the provision of global Internet services. There has been a strong trend towards convergence of communication services in recent times, with the Internet providing the ideal platform on which to base such convergence. Even traditional circuit-switched applications (such as voice and video streaming) have been shown to work effectively over the Internet. Although the Internet is prevalent in the developed world, satellites are vital to extending this into more remote and sparsely populated regions of the world. It is therefore important that satellite technology is advanced to provide seamless interoperability with the Internet and adequate Quality of Service (QoS) support. The purpose of this special issue is to present research devoted to furthering satellite technology and networking to support the provision of both current and future applications.
    • Temperature dependent stiffness and visco-elastic behaviour of lipid coated microbubbles using atomic force microscopy.

      Grant, Colin A.; McKendry, J.E.; Evans, S.D. (03/11/2011)
      The compression stiffness of a phospholipid microbubble was determined using force-spectroscopy as a function of temperature. The stiffness was found to decrease by approximately a factor of three from 0.08 N m 1, at 10 C, down to 0.03 N m 1 at 37 C. This temperature dependence indicates that the surface tension of lipid coating is the dominant contribution to the microbubble stiffness. The timedependent material properties, e.g. creep, increased non-linearly with temperature, showing a factor of two increase in creep-displacement, from 24 nm, at 10 C, to 50 nm, at 37 C. The standard linear solid model was used to extract the visco-elastic parameters and their determination at different temperatures allowed the first determination of the activation energy for creep, for a microbubble, to be determined.
    • Automated Solar Activity Prediction: A hybrid computer platform using machine learning and solar imaging for automated prediction of solar flares

      Colak, Tufan; Qahwaji, Rami S.R. (AGU, 04/06/2009)
      The importance of real-time processing of solar data especially for space weather applications is increasing continuously. In this paper, we present an automated hybrid computer platform for the short-term prediction of significant solar flares using SOHO/Michelson Doppler Imager images. This platform is called the Automated Solar Activity Prediction tool (ASAP). This system integrates image processing and machine learning to deliver these predictions. A machine learning-based system is designed to analyze years of sunspot and flare data to create associations that can be represented using computer-based learning rules. An imaging-based real-time system that provides automated detection, grouping, and then classification of recent sunspots based on the McIntosh classification is also created and integrated within this system. The properties of the sunspot regions are extracted automatically by the imaging system and processed using the machine learning rules to generate the real-time predictions. Several performance measurement criteria are used and the results are provided in this paper. Also, quadratic score is used to compare the prediction results of ASAP with NOAA Space Weather Prediction Center (SWPC) between 1999 and 2002, and it is shown that ASAP generates more accurate predictions compared to SWPC.
    • Dynamic mechanical analysis of collagen fibrils at the nanoscale.

      Grant, Colin A.; Phillips, M.A.; Thompson, N.H. (05/09/2011)
      Low frequency (0.1¿2 Hz) dynamic mechanical analysis on individual type I collagen fibrils has been carried out using atomic force microscopy (AFM). Both the elastic (static) and viscous (dynamic) responses are correlated to the characteristic axial banding, gap and overlap regions. The elastic modulus (¿5 GPa) on the overlap region, where the density of tropocollagen is highest, is 160% that of the gap region. The amount of dissipation on each region is frequency dependent, with the gap region dissipating most energy at the lowest frequencies (0.1 Hz) and crossing over with the overlap region at ¿0.75 Hz. This may reflect an ability of collagen fibrils to absorb energy over a range of frequencies using more than one mechanism, which is suggested as an evolutionary driver for the mechanical role of type I collagen in connective tissues and organs.
    • Design and evaluation of M-Commerce applications.

      Wang, Jia Jia; Lei, Pouwan; Sheriff, Ray E. (IEEE, 05/10/2005)
      Recent advances in wireless technology have increased the number of mobile device users and given pace to the rapid development and deployment of e-commerce to the mobile user. This new type of e-commerce, conducting transactions via mobile terminals, is called mobile commerce (mcommerce). Due to its inherent characteristics such as ubiquity, personalization, flexibility, and dissemination, mobile commerce promises business unprecedented market potential, greater productivity and higher profitability. With this in mind, it is perhaps not surprising that mobile commerce is growing much faster than its fixed counterpart. Unlike e-commerce, m-commerce is more personalized and there is a need for a novel approach to evaluating m-commerce applications. This paper examines the issues in designing mcommerce applications not only from a technical viewpoint but also from the end users¿ perspective.
    • Static and dynamic nanomechanical properties of human skin tissue using atomic force microscopy: Effect of scarring in the upper dermis.

      Grant, Colin A.; Twigg, Peter C.; Tobin, Desmond J. (06/07/2012)
      Following traumatic injury, skin has the capacity to repair itself through a complex cascade of biochemical change. The dermis, which contains a load-bearing collagenous network structure, is remodelled over a long period of time, affecting its mechanical behaviour. This study examines the nanomechanical and viscoelastic properties of the upper dermis from human skin that includes both healthy intact and scarred tissue. Extensive nanoindentation analysis shows that the dermal scar tissue exhibits stiffer behaviour than the healthy intact skin. The scar skin also shows weaker viscoelastic creep and capability to dissipate energy at physiologically relevant frequencies than the adjacent intact skin. These results are discussed in conjunction with a visual change in the orientation of collagenous fibrils in the scarred dermis compared with normal dermis, as shown by atomic force microscopy imaging.
    • Optimum Design of Doherty RFPA for Mobile WiMAX Base Stations

      Ghazaany, Tahereh S.; Abd-Alhameed, Raed A.; Child, Mark B.; Ali, N.T.; Rodriguez, Jonathan; Hussaini, Abubakar S. (Springer for the ICST, 06/09/2010)
      RF power amplifiers in mobile WiMAX transceivers operate in an inherently nonlinear manner. It is possible to amplify the signal in the linear region, and avoid distortion, using output power back-off; however, this approach may suffer significant reduction in efficiency and power output. This paper investigates the use of Doherty techniques instead of back-off, to simultaneously achieve good efficiency and acceptable linearity. A 3.5 GHz Doherty RFPA has been designed and optimized using a large signal model simulation of the active device, and performance analysis under different drive levels. However, the Doherty EVM is generally poor for mobile WiMAX. Linearity may be improved by further digital pre-distortion, and a simple pre-distortion method using forward and reverse AM-AM and AM-PM modeling. Measurements on the realized amplifier show that this approach satisfies the EVM requirements for WiMAX base stations. It exhibits a PAE over 60%, and increases the maximum linear output power to 43 dBm, whilst improving the EVM.
    • Improvements in Multicarrier Modulation Systems using a Wavelet OFDM Scheme

      Karkhaneh, H.; Ghazaany, Tahereh S.; Abd-Alhameed, Raed A.; Child, Mark B.; Ghorbani, A.; Rasheed, W.; Elkhazmi, Elmahdi A. (06/09/2010)
      This paper investigates the performance of wavelet OFDM signals over a wireless communications link. The scheme is shown to be generally similar to Fourier based OFDM, but with some additional features, and improved characteristics. The sensitivity of both schemes to the nonlinear amplification in the transmitter is compared by monitoring the time domain output data and the adjacent channel power ratio (ACPR) performance.
    • Assessing variability in the wideband mobile radio channel.

      Jones, Steven M.R.; Samarah, Khalid G.; Dama, Yousef A.S.; Abd-Alhameed, Raed A.; Rasheed, W.; Elkhazmi, Elmahdi A. (06/09/2010)
      An assessment of the performance of OFDM transmissions over the wideband mobile radio channel is reported. The simulation in MATLAB /Simulink is based on the CODIT channel model. The results show that BER deteriorates significantly as the mobile velocities increase from 0 to 30 m/s. Significant variability in the BER for a given channel type is quantified. For a given instance of the channel the standard deviation of the estimated BER is 20%, but when averaged over many separate instances of the same channel type, a standard deviation of 47% is found.
    • Distance learning of engineering based subjects: A case study.

      Ong, Felicia Li Chin; Sheriff, Ray E. (07/06/2009)
      With the advancement of technology, significant changes have been introduced into the learning and teaching environment. The importance of enhancing the interest of learners is an on-going challenge for educators of all levels. In this respect, teaching and learning practices are adapting to students¿ exposure to technological and social trends. In this presentation, a case study of using technology to enhance the learners¿ environment for engineering-based subjects in higher education is presented. The approach consists of delivering interactive materials through a Virtual Learning Environment and integrating web application technologies to enhance the learners¿ experience. Due to the vast subject areas in engineering and the variety of content of each subject, a general methodology is first identified and adopted. This consists of stages that show the progress from initial development to deployment of the materials, followed by evaluation of the module and further improvements carried out on the module based on qualitative evaluation. The evaluation process consists of the application of electronic surveys for feedback on the distance learning module. In addition, monitoring of the students¿ usage of the materials is also carried out. The presentation concludes with the presentation of the initial results from a current e-learning module.
    • Analysis of the Effect of EBG on the Mutual Coupling for a two-PIFA Assembly.

      Abidin, Z.Z.; Abd-Alhameed, Raed A.; McEwan, R.A.; Child, Mark B. (08/11/2010)
      Size constraints and mutual coupling on the performance of a two-element PIFA assembly are investigated for a design frequency of 2.4 GHz. A benchmark antenna assembly, employing a normal metallic ground plane is compared with an EBG modified ground plane. The height of the antenna elements over the EBG is optimised, and an isolation factor of 9.12 dB is achieved for a gap of 2.5 mm. Prototype structures have been constructed and measured for both cases.
    • Calculation of the Spatial Envelope Correlation Between Two Antennas in Terms of the System Scattering Parameters Including Conducting Losses.

      Dama, Yousef A.S.; Abd-Alhameed, Raed A.; Zhou, Dawei; Jones, Steven M.R.; Child, Mark B.; Excell, Peter S. (08/11/2010)
      The envelope correlation for a two-element antenna array may be calculated using the antenna radiation fields, or more simply from the scattering parameters of the system. The use of scattering parameters provides a major simplification over the direct use of field data. In this paper we propose a modification of the scattering parameter method which also includes the antenna losses. This approach has the advantage of simplifying the antenna design process, especially when low envelope correlations are needed. It also offers a better prediction of the spatial envelope correlation, and a good framework for understanding the effects of the mutual coupling. The accuracy of this proposed method is illustrated by two examples.
    • Interaction Between Electromagnetic Field and Human Body for Dual Band Balanced Antenna Using Hybrid Computational Method

      Alhaddad, A.G.; Ramli, Khairun N.; Abd-Alhameed, Raed A.; Zhou, Dawei (08/11/2010)
      This paper describes a hybrid computational method which efficiently models the interaction between a small antenna placed in proximity with the human body. Results for several test cases of placed in different locations on the body are presented and discussed. The near and far fields were incorporated into the study to provide a full understanding of the impact on human tissue. The cumulative distribution function of the radiation efficiency and absorbed power is also provided. The antennas are assumed to be operating over the 2.4 GHz and 5.2 GHz WLAN frequencies.
    • Analysis of heat partition ratio in vehicle braking processes.

      Loizou, Andreas; Qi, Hong Sheng; Day, Andrew J. (Institution of Mechanical Engineers, 09/06/2009)
      An examination of the heat partition ratio between the friction surfaces of a disc braking system is presented using finite element analysis (FEA). This includes a 2D static analysis of two semi-infinite bodies in contact with and without an interface layer which represents the interface tribo-layer (ITL). An analytical approach with a finite difference solution was used for cross-comparison with the static FE models. Results from the static model have provided the boundary conditions for a 2D dynamic model, where one rectangular block slides on another (fixed) rectangular block. The effects of normal loads and real contact area have also been studied.
    • Satellite Communications [Editorial]

      Sheriff, Ray E.; Donner, A.; Vanelli-Coralli, A. (Hindawi Publishing Corporation., 09/12/2007)
      We are delighted to bring to you this special issue on satellite communications, which we have prepared as part of the spreading of excellence remit of the satellite communications network of excellence (SatNEx). The SatNEx project, which began in 2004, is funded for five years under the European Union¿s Sixth Framework Programme (FP6) Information Society Technologies (IST) Thematic Area. Led by the German Aerospace Center, SatNEx brings together a network of 24 partners, distributed throughout Europe, with membership drawn from ten countries. The philosophy underlying the SatNEx approach revolves around the selection of focused actions under Joint Programmes of Activities, which are carried out collectively by the partners and include research, integration, and dissemination activities. Training represents an important part of the SatNEx remit and is supported through a number of initiatives including the hosting of internship projects and an annual summer school. The call for papers resulted in a high number of submissions, from which we have been able to select 12 excellent papers dealing with the different aspects of satellite communications and navigation.