• Deposition of charged inhaled aerosols with transient airflow in sequential lung airway model

      Koolpiruck, Diew; Prakoonwit, Simant; Balachandran, Wamadeva (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2004)
    • The development of a parallel ray launching algorithm for wireless network planning

      Lai, Zhihua; Bessis, Nik; De La Roche, Guillaume; Kuonen, Pierre; Zhang, Jie; Clapworthy, Gordon J. (IGI Publishing, 2011)
    • Diode-based IQ imbalance estimation in direct conversion transmitters

      Xiong, Jian; Zhang, Yue; Li, Wei; Wang, Jin; Huang, Li-Ke; Maple, Carsten; University of Bedfordshire; Aeroflex, Stevenage; Shanghai Jiao Tong University (IEEE, 2014-02)
      Direct conversion transmitters are widely used in wireless systems for their inherent features of being simple and low cost. In this architecture, the inphase (I branch) and quadrature signal (Q branch) will be unconverted to the RF frequency band by quadrature modulation. However, the drawback of the direct conversion architecture is that it is sensitive to IQ imbalance caused by the impairment of analogue devices in I and Q branches. It then results in interferences in mirror frequencies which degrades the signal quality. Therefore, the accurate measurement of IQ imbalance is crucial. A diode-based method to measure the broadband IQ imbalance is proposed which does not need additional measurement instruments. Measurement results show the effectiveness of this method
    • Distributed pixel mapping for refining dark area in parallax barriers based holoscopic 3D Display

      Swash, M.R.; Aggoun, Amar; Fatah, O. Abdul; Fernandez, Juan C. J.; Alazawi, E.; Tsekleves, Emmanuel; Brunel University; University of Bedfordshire (IEEE, 2013-12)
      Autostereoscopic 3D Display is robustly developed and available in the market for both home and professional users. However 3D resolution with acceptable 3D image quality remains a great challenge. This paper proposes a novel pixel mapping method for refining dark areas between two pinholes by distributing it into 3 times smaller dark areas and creating micro-pinholes in parallax barriers based holoscopic 3D displays. The proposed method allows to project RED, GREEN, BLUE subpixels separately from 3 different pinholes and it distributes the dark spaces into 3 times smaller dark spaces, which become unnoticeable and improves quality of the constructed holoscopic 3D scene significantly. Parallax barrier technology refers to a pinhole sheet or device placed in front or back of a liquid crystal display, allowing to project viewpoint pixels into space that reconstructs a holoscopic 3D scene in space. The holoscopic technology mimics the imaging system of insects, such as the fly, utilizing a single camera, equipped with a large number of micro-lenses or pinholes, to capture a scene, offering rich parallax information and enhanced 3D feeling without the need of wearing specific eyewear.
    • Dynamic hyperlinker for 3D content search and retrieval

      Swash, M.R.; Aggoun, Amar; Fatah, O. Abdul; Li, B.; Fernandez, Juan C. J.; Tsekleves, Emmanuel; Brunel University; University of Bedfordshire (IEEE, 2013-06)
      Recently, 3D display technology, and content preparation and creation tools have been under vigorous development. Consequently, they are also widely adopted by home and professional users. 3D digital repositories are increasing and becoming available ubiquitously. However, there is not yet a single 3D content search and retrieval platform. In this paper, we propose and present the development of a novel approach for 3D content search and retrieval which is called Dynamic hyperlinker for 3D content search and retrieval. It advances 3D multimedia navigability and searchability by creating dynamic links for selectable and clickable objects in the scene while the 3D video clip is being replayed. The proposed system involves 3D video processing, such as detecting/tracking clickable objects, annotating objects, and metadata engineering. Such system attracts the attention from both home and professional users such as broadcasters and digital content providers. The experiment is conducted on Holoscopic 3D images “also known as integral images.
    • Dynamic PCI assignment in two-tier networks based on cell activity prediction

      Zhang, J.; Zhang, X.; Xiao, Z.; Liu, Enjie; University of Bedfordshire; Hunan University; University of Sheffield (IET, 2013-11)
      Physical cell identity (PCI) is used to identify each cell. However, with the introduction of femtocells, 8 bytes allocation for PCI cannot accommodate a large number of femtocells. The current solution in 3GPP Release 9 is to use cell global identity associated with PCI to resolve this problem. However, this solution may incur higher inbound handover failure. A dynamic PCI assignment based on cell activity level prediction is proposed. The system level simulation showed that the approach outperforms the existing approaches.
    • Dynamic user equipment-based hysteresis-adjusting algorithm in LTE femtocell networks

      Xiao, Zhu; Zhang, Xu; Maple, Carsten; Allen, Ben; Liu, Enjie; Mahato, Shyam Babu; University of Bedfordshire; Southeast University, Nanjing; Hunan University, Chang sha; University of Warwick (IEEE, 2014-09)
      In long-term evolution (LTE) femtocell networks, hysteresis is one of the main parameters which affects the performance of handover with a number of unnecessary handovers, including ping-pong, early, late and incorrect handovers. In this study, the authors propose a hybrid algorithm that aims to obtain the optimised unique hysteresis for an individual mobile user moving at various speeds during the inbound handover process. This algorithm is proposed for two-tier scenarios with macro and femto. The centralised function in this study evaluates the overall handover performance indicator. Then, the handover aggregate performance indicator (HAPI) is used to determine an optimal configuration. Based on the received reference signal-to-interference-plus-noise ratio, the distributed function residing on the user equipment (UE) is able to obtain an optimal unique hysteresis for the individual UE. Theoretical analysis with three indication boundaries is provided to evaluate the proposed algorithm. A system-level simulation is presented, and the proposed algorithm outperformed the existing approaches in terms of handover failure, call-drop and redundancy handover ratios and also achieved better overall system performance.
    • Editorial

      Clapworthy, Gordon J.; Viceconti, Marco; Coveney, Peter V.; Kohl, Peter (Royal Society Publishing, 2008-09)
    • Editorial

      Kohl, Peter; Coveney, Peter V.; Clapworthy, Gordon J.; Viceconti, Marco (Royal Society Publishing, 2008-09)
      The second issue of Phil. Trans. R. Soc. A, devoted to ‘The virtual physiological human’, highlights the challenges involved in organ-level modelling of biological systems.
    • Enabling the interactive display of large medical volume datasets by multiresolution bricking

      Agrawal, Anupam; Kohout, Josef; Clapworthy, Gordon J.; McFarlane, Nigel J.B.; Dong, Feng; Viceconti, Marco; Taddei, Fulvia; Testi, Debora (SpringerLink, 2010)
    • Energy-saving MAC protocols for Point-Controlled Wireless Networks: Best-Effort, QoS

      Safdar, Ghazanfar Ali (VDM Verlag, 2010)
      As wireless networks become an integral component of the modern communication infrastructure, energy efficiency will be an important design consideration due to the limited battery life of mobile and portable terminals. Such devices must operate with the highest possible energy efficiency while still maintaining a minimum quality of service to meet the user?s expectations. PCSAR, a new power-saving MAC protocol for centralized control wireless networks is presented in this book. The book contains power saving techniques employed by standards for WPAN and WLANs, such as Bluetooth, Zigbee, HiperLan, and IEEE 802.11. The steady state performance of PCSAR was compared with IEEE 802.11b power saving mode (PCF-PS) using DES of a typical WLAN scenario. To account for effect of errors on performance, PCSAR was also compared with PCF-PS for both uncorrelated and time-correlated channel models. Finally, PCSAR was modified to suit a QoS enabled MAC such as IEEE 802.11e. This book should be useful for professionals both in academics and industry, in the field of wireless communications and networking, especially those engaged in the development of MAC protocols for wireless networks
    • Enhancing Bayesian estimators for removing camera shake

      Wang, Chao; Yue, Y.; Dong, Feng; Tao, Yubo; Ma, Xiangyin; Clapworthy, Gordon J.; Ye, Xujiong; University of Bedfordshire (Wiley, 2013)
      The aim of removing camera shake is to estimate a sharp version x from a shaken image y when the blur kernel k is unknown. Recent research on this topic evolved through two paradigms called MAP(k) and MAP(x,k). MAP(k) only solves for k by marginalizing the image prior, while MAP(x,k) recovers both x and k by selecting the mode of the posterior distribution. This paper first systematically analyses the latent limitations of these two estimators through Bayesian analysis. We explain the reason why it is so difficult for image statistics to solve the previously reported MAP(x,k) failure. Then we show that the leading MAP(x,k) methods, which depend on efficient prediction of large step edges, are not robust to natural images due to the diversity of edges. MAP(k), although much more robust to diverse edges, is constrained by two factors: the prior variation over different images, and the ratio between image size and kernel size. To overcome these limitations, we introduce an inter-scale prior prediction scheme and a principled mechanism for integrating the sharpening filter into MAP(k). Both qualitative results and extensive quantitative comparisons demonstrate that our algorithm outperforms state-of-the-art methods.
    • The EuroPhysiome, STEP and a roadmap for the virtual physiological human

      Fenner, J.W; Brook, B.; Clapworthy, Gordon J.; Coveney, Peter V.; Feipel, V.; Gregersen, H.; Hose, D.R.; Kohl, Peter; Lawford, Patricia; McCormack, K.M.; et al. (The Royal Society, 2008-09)
    • Evaluation of a statistical model for the characterization of multipath affecting mobile terminal GPS antennas in sub-urban areas

      Ur-Rehman, Masood; Chen, Xiaodong; Parini, Clive G.; Ying, Zhinong (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2012-02)
      This paper describes and validates a technique to characterize the environmental effects on mobile terminal GPS antennas using statistical model. This method requires the knowledge of 3-D free space antenna gain patterns and average angular distribution of incident power in the environment. The power distribution must be known in both elevation and azimuth and separately for parallel and perpendicular polarizations. The antenna performance is assessed in terms of GPS Mean Effective Gain (MEGGPS) and GPS Coverage Efficiency (ηc). Angle of Arrival (AoAGPS) distributions of incident GPS radio waves arriving at the mobile terminal are assumed to be randomly uniform in both the azimuth and elevation planes. It effectively replicates the open field (sub-urban) working conditions for the mobile terminal GPS antennas. The method could be adapted to an urban environment by introducing the information of AoAGPS distributions. A lengthy open field measurement campaign based on received signal-to-noise ratio (SNR) and mean number of tracked GPS satellites is carried out to validate the statistical model.
    • Evolution and sustainability of a wildlife monitoring sensor network

      Dyo, Vladimir; Yousef, Kharsim; Ellwood, Stephen A.; Macdonald, David W.; Markham, Andrew; Mascolo, Cecilia; Pásztor, Bence; Scellato, Salvatore; Trigoni, Niki; Wohlers, Ricklef (ACM, 2010)
      In this paper, we report the findings from a one year deployment of an automated wildlife monitoring system for analyzing the social co-location patterns of European badgers (Meles meles) residing in a dense woodland environment. We describe the stages of its evolution cycle, from implementation, deployment and testing, to various iterations of software optimization, followed by hardware enhancements, which in turn triggered the need for further software optimization. We report preliminary descriptive analyses of a subset of the data collected, demonstrating the significant potential our system has to generate new insights into badger behavior. The main lessons learned were: the need to factor in the maintenance costs while designing the system; to look carefully at software and hardware interactions; the importance of a rapid initial prototype deployment (this was key to our success); and the need for continuous interaction with domain scientists which allows for unexpected optimizations.
    • Face to face: anthropometry-based interactive face shape modeling using model priors

      Zhang, Yu; Prakash, Edmond C. (Hindawi, 2009)
      This paper presents a new anthropometrics-based method for generating realistic, controllable face models. Our method establishes an intuitive and efficient interface to facilitate procedures for interactive 3D face modeling and editing. It takes 3D face scans as examples in order to exploit the variations presented in the real faces of individuals. The system automatically learns a model prior from the data-sets of example meshes of facial features using principal component analysis (PCA) and uses it to regulate the naturalness of synthesized faces. For each facial feature, we compute a set of anthropometric measurements to parameterize the example meshes into a measurement space. Using PCA coefficients as a compact shape presentation, we formulate the face modeling problem in a scattered data interpolation framework which takes the user-specified nthropometric parameters as input. Solving the interpolation problem in a reduced subspace allows us to generate a natural face shape that satisfies the user-specified constraints. At runtime, the new face shape can be generated at an interactive rate. We demonstrate the utility of our method by presenting several applications, including analysis of facial features of subjects in different race groups, facial feature transfer, and adapting face models to a particular population group.
    • Fast isosurface rendering on a GPU by cell rasterization

      Liu, Baoquan; Clapworthy, Gordon J.; Dong, Feng (Blackwell Publishing, 2009-12)
    • Feature enhancement by volumetric unsharp masking

      Tao, Yubo; Lin, Hai; Bao, Hujun; Dong, Feng; Clapworthy, Gordon J. (SpringerLink, 2009-04)
    • Finding a set of optimal viewing for 3D surface reconstruction from 2D X-ray images using genetic algorithm

      Prakoonwit, Simant; University of Reading (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2010)
    • Generating stereoscopic 3D from holoscopic 3D

      Fatah, O. Abdul; Aggoun, Amar; Swash, M.R.; Alazawi, E.; Li, B.; Fernandez, Juan C. J.; Chen, D.; Tsekleves, Emmanuel; University of Bedfordshire; Brunel University (IEEE, 2013-10)
      In this paper a single aperture motion picture camera based on holoscopic imaging used to generate high-resolution stereoscopic image. The idea of single aperture camera reduces the very cumbersome and expensive of dual cameras in stereoscopic production. The camera is known as light field camera, which was first proposed in 1908 by lippmann [1]. The rendering method relied on up-sampling, shift and integrating of different views to extract stereo images. This is the first experiment attempted to generate stereo form holoscopic content on motion capturing, where researchers so far have been experimenting on still images. In this paper presents motion picture image rendering on holoscopic content to generate content for stereoscopic systems. We have carried out experiments with focused plenoptic camera on a single stage omnidirectional integral camera arrangement with capturing both horizontal and vertical parallax, using a low cost lens array and relay lens. Our results show an improvement in the resolution of images with artefact free and also the rendered stereo content are played back on polarized stereoscopic system and anaglyph system to perceive the 3D depth using filter glasses in our experimental section.