1,721,631 research outputs found
Development and applications of high performance computing
No full textIn this thesis we demonstrate the application of high performance computing techniques to three scientific problems. The first uses the Maximum Entropy method to determine structure in players' choices of numbers in the UK National Lottery. The resulting equations are solved using an efficient parallel algorithm. We find that players preferentially pick numbers in the centre of the ticket. The second is a model for cooperation in groups, in which the parameter space of the model is explored using task farming. We demonstrate, using a simple model, that it is possible to sustain cooperation in large groups when there is repeated interaction, recognition of the identity of individual participants, and memory of the outcomes of previous encounters. In larger groups, players with longer memories are favoured, supporting the conjecture that the selection pressures leading to large primate groups resulted in an increased neocortex size. Thirdly we have constructed a theoretical model for the electro-optic properties of polymer dispersed liquid crystal systems and provided a full numerical solution for the governing equations. This yields a detailed description of the optical response of the system to an applied field.</p
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
The Semantic Web as a Semantic Soup
Full text linkThe Semantic Web is currently best known for adding metadata to web pages to allow computers to 'understand' what they contain. This idea has been applied to people by the Friend of a Friend project which builds up a network of who people know through their descriptions placed on web pages in RDF. It is here proposed to use RDF to describe a person and to have their RDF document follow them around the Internet. The proposed technique, dubbed Semantic Cookies, will be implemented by storing a user's RDF in a cookie on their own computer through the browser. This paper considers the concept of Semantic Cookies and investigates how far existing technology can be pushed to accommodate the idea
Using the MEAN Stack to implement a RESTful service for an Internet of Things Application
No full textThis paper examines the components of the MEAN development stack (MongoDb, Express.js, Angular.js, & Node.js), and demonstrate their benefits and appropriateness to be used in implementing RESTful web-service APIs for Inter- net of Things (IoT) appliances. In particular, we show an end- to-end example of this stack and discuss in detail the various components required. The paper also describes an approach to establishing a secure mechanism for communicating with IoT devices, using pull-communications
Recommendations for securing Internet of Things devices using commodity hardware.
No full textThe Internet of Things (IoT) describes a world where ubiquitous devices such as sensors are all capable of communicating with the Internet. The concept of Internet enabling devices is not new, however the popularity of IoT promises to increase the number of connected devices considerably.
Ubiquitous IoT devices have serious security implications as they occur in large numbers, are geographically distributed and can be difficult to physically secure. These devices may contain sensitive or commercially valuable data making them attractive to various forms of attack.</span
Parallel numerical modelling of the Antarctic Ice Sheet
No full textThe Antarctic Ice Sheet comprises the West Antarctic Ice Sheet and the much larger East Antarctic Ice Sheet. Fast flowing ice streams and outlet glaciers are important dynamic components of the ice sheet system, and a grid resolution of at least 20 km is required to identify many of these areas. Previous fine resolution numerical models have focussed on ice flow in West Antarctica or on fine resolution modelling of subsections of the ice sheet, since the size of East Antarctica has generally precluded studies of the whole ice sheet at a resolution adequate to identify complex flow features.The equations describing ice flow are highly non-linear, making this a computationally intensive problem. We use a staggered grid for calculation of ice diffusivity to overcome numerical instability, and a sparse packing scheme to take account of the irregular boundary of Antarctica. We have developed an efficient parallel temperature-dependent ice flow model of the entire grounded portion of the Antarctic Ice Sheet at a resolution of 20 km. The model was primarily written to run on a commodity cluster of workstations, and performance results for this and other systems are presented. Ice flow patterns at steady state compare well with recently published balance velocity calculations
Solving an eigenvalue problem on a periodic domain using a radial basis function finite differences scheme
No full textLocal radial basis functions (RBFs) are becoming increasingly popular as an alternative to global RBFs, as the latter suffer from ill-conditioning. In this paper, a local meshless method based on RBFs in a finite-difference (FD) mode with better conditioned matrices has been developed for solving an eigenvalue problem with a periodic domain. Through numerical experiments, we examine the accuracy of the method as a result of variation in the number and layout of nodes in the domain and the effects of shape parameter, using various globally supported RBFs. The presented scheme has been validated on two different types of nodal arrangement, namely uniform and non-uniform node distributions. The results obtained from the method are found to be in good agreement with the benchmark analytical solutions. In addition, a higher-order RBF-FD scheme (which uses ideas from Hermite interpolation) is then proposed for solving the eigenvalue problem with a periodic domain. Tests show that both accuracy and convergence order can be improved dramatically by using higher-order RBF-FD formulae, which converge at a rate of O(h8.5) compared to the standard-order method which converges as O(h4.3) for uniformly distributed nodes with spacing h
Metagit GitHub Repository
No full textMetagit-py and metagit-mac are prototype tools to demonstrate the Metagit model, discussed in the following publication: Scott, Mark, Steven J. Johnston, and Simon J. Cox (2016). "Metagit: Decentralised Metadata Management With Git". In: Information Systems. DOI: 10.1016/j.is.2016.09.002.
This dataset contains clones of the GitHub repositories metagit-py (https://github.com/mscottuk/metagit-py) and metagit-mac (https://github.com/mscottuk/metagit-mac) as they were on 14/09/2016 to support the above publication.</span
Multiresolution Computed Tomography Viewer
Full text linkThe Multiresolution Computed Tomography Viewer, MCTV, allows large images from a micro-CT to be displayed over the web, whilst being easy to set up and not requiring any plug-ins to be enabled apart from JavaScript which is by default enabled on all major browsers. It allows easy navigation through a 3D image as well as modification of the threshold using JavaScript canvas.
This code is based on the Multiresolution Image Viewer by Shawn Mikula (available at http://www.connectomes.org).
A code for creating the tiles for the viewer is provided as part of LungJ (https://doi.org/10.5258/SOTON/401280)</span
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