1,720,972 research outputs found
Science and technology for the future
No full textDr Marc Molinari, Southampton Regional e-Science Centre, School of Engineering Sciences, looks at the increasing demand for Grid computing
High fidelity imaging in electrical impedance tomography
No full textThis thesis addresses the computational reconstruction of images using Electrical Impedance Tomography (EIT). EIT is an imaging method, in which electrical currents are injected through electrodes into a conducting volume and the resulting potential distribution is measured at surface electrodes. From these potentials, an image of the electrical conductivity can be obtained using numerical reconstruction techniques. This non-linear reconstruction is mathematically difficult and computationally intensive. Most applications in medicine and industry rely upon a fast and accurate image acquisition. The aim of this investigation is to find methods which improve the speed and accuracy of EIT by a range of improvements to the numerical methods used in the forward solution and inverse reconstruction. We investigate the impact of the finite element discretization on the performance of computing the electric field forward solution. We derive an a posteriori error estimate on the finite element mesh and implement 2D adaptive mesh refinement techniques in an optimised forward solver. Our results of this novel approach show that a speed-up of approximately an order of magnitude can be obtained. We extend the developed iterative Newton-Raphson algorithm to include image smoothness constraints and adaptive mesh refinement based on conductivity gradients in the image. The results show that the image resolution can be made independent of the underlying numerical discretization and therefore is limited only by the level of noise present in the measurements. An additional benefit of this new technique is the automatic focus of available computational resources on key regions for forward solution and inverse reconstruction. As 3D impedance imaging becomes computationally too expensive for the Newton-Raphson method, we develop a novel non-linear conjugate gradient algorithm incorporating 3D adaptive mesh refinement routines, and present results showing the decrease of memory requirements and the increase in image reconstruction performance. In addition, a Matlab software package containing optimised routines for the finite element-based computations in EIT has been developed as part of this work. Finally, we outline a method for obtaining a map for the determination of the reconstruction reliability and image correlation of an EIT algorithm. With the improvements to reconstruction accuracy and speed investigated in this thesis, we conclude that efficient non-linear 3D impedance imaging is feasibl
Combining physical simulations and chargeable web service applications in engineering workflows
No full textWe demonstrate with a case study extending previous work how to integrate and consume a distributed framework for chargeable Web services providing a specialist software package for engineering applications and show with an example how this service can be integrated into scientific research problems in science and engineering. We discuss the complexity of the problem and list some of the issues encountered
Integration of chargeable web services into engineering applications
No full textWe discuss an engineering case-study in which we address the issues of integration and secure consumption of a specialist software package for finite element meshing through a web service based interface. This work focuses on demonstrating the end-to-end requirements of a framework allowing the transparent integration of the web service into the design workflow of an engineering user. After detailing an example engineering problem, we discuss server-side issues and required modules such as local accounting, security and resource management which provide a sample framework for a chargeable web service. We then demonstrate how the client can easily interface to and consume the web service from within the engineering scripting language Matlab
GeodiseLab: making the grid usable
No full textThe GeodiseLab project is supported by the OMII managed programme to extend and improve the Geodise toolboxes which provide Grid client functionality to Problem Solving Environments (PSEs) used by engineers and scientists. The three key areas of development in the Geodise toolboxes have been: extending the functionality of the toolboxes, supporting additional environments, and hardening the toolboxes for public release. The Geodise computational toolboxes now support additional Grid technologies, including Condor and the OMII_1 platform. Recent enhancements to the Geodise Database and XML Toolbox are described. The Jython scripting environment is now supported in addition to the Matlab technical computing environment. We also discuss the software engineering process used to harden the toolboxes for public release, and the usability issues highlighted by feedback from users. Finally, a new application of the Geodise toolboxes in the domain of Electric Impedance Tomography is presented
Grid-enabled electromagnetic optimisation (GEM) for industrial use.
No full textWe have developed a tool for parametric electromagnetic design studies using industrial analysis code for the design search and optimisation of photonic crystals. This software tool allows engineering users to transparently access Grid compute components for an end-to-end design of a photonic device using computational electromagnetics. In this paper, we give an overview of the industrial application background, present some aspects of the interface developed, and discuss some of the issues involved in the computational tasks and the storage of metadata
Extensible efficient handling of metadata for e-Science
No full textThe Geodise data management platform provides a Grid-enabled distributed file and data archive and enables users to annotate their data with rich descriptive metadata in the form of XML. We present a process model for the evolution of the Geodise data management system from a free and flexible repository to a structured scalable relational database for production purposes. The model is designed to aid scientists and engineers to develop XML Schemas describing their metadata requirement which can be registered in the XML-enabled database to provide a scalable back-end solution without any impact to the existing client side application
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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