http://hdl.handle.net/10204/3215 2013-05-20T16:47:17Z 2013-05-20T16:47:17Z Raccanelli, A Zhao, G-B Bacon, DJ Jarvis, MJ Percival, WJ Norris, RP Rottgering, H Abdalla, FB Cress, CM Kubwimana, J-C Lindsay, S Nichol, RC Santos, MG Schwarz, DJ http://hdl.handle.net/10204/6704 2013-04-19T21:55:18Z 2012-08-01T00:00:00Z

Title: Cosmological measurements with forthcoming radio continuum surveys Authors: Raccanelli, A; Zhao, G-B; Bacon, DJ; Jarvis, MJ; Percival, WJ; Norris, RP; Rottgering, H; Abdalla, FB; Cress, CM; Kubwimana, J-C; Lindsay, S; Nichol, RC; Santos, MG; Schwarz, DJ Abstract: We present forecasts for constraints on cosmological models that can be obtained using the forthcoming radio continuum surveys: the wide surveys with the Low Frequency Array (LOFAR) for radio astronomy, theAustralian SquareKilometreArray Pathfinder (ASKAP) and theWesterbork Observations of the Deep Apertif Northern Sky (WODAN).We use simulated catalogues that are appropriate to the planned surveys in order to predict measurements obtained with the source autocorrelation, the cross-correlation between radio sources and cosmic microwave background (CMB) maps (the integrated Sachs–Wolfe effect), the crosscorrelation of radio sources with foreground objects resulting from cosmic magnification, and a joint analysis together with the CMB power spectrum and supernovae (SNe). We show that near-future radio surveys will bring complementary measurements to other experiments, probing different cosmological volumes and having different systematics. Our results show that the unprecedented sky coverage of these surveys combined should provide the most significant measurement yet of the integrated Sachs–Wolfe effect. In addition, we show that the use of the integrated Sachs–Wolfe effect will significantly tighten the constraints on modified gravity parameters, while the best measurements of dark energy models will come from galaxy autocorrelation function analyses. Using a combination of the EvolutionaryMap of the Universe (EMU) and WODAN to provide a full-sky survey, it will be possible to measure the dark energy parameters with an uncertainty of {s(w0)=0.05, s(wa)=0.12} and themodified gravity parameters {s( 0) = 0.10, s(µ0) = 0.05}, assuming Planck CMB+SN (current data) priors. Finally, we show that radio surveys would detect a primordial non-Gaussianity of f NL =8 at 1s, and we briefly discuss other promising probes. Description: Copyright: 2012 Royal Astronomical Society. Published in Monthly Notices of the Royal Astronomical Society, vol. 424(2), pp 801-819

2012-08-01T00:00:00Z Seotsanyana, M http://hdl.handle.net/10204/6698 2013-04-19T21:55:14Z 2012-08-01T00:00:00Z

Title: Temporal logic motion planning in robotics Authors: Seotsanyana, M Abstract: Robotic computer systems have become increasingly ubiquitous in everyday life and this has led to a need to develop safe and reliable robot systems. Description: Copyright: 2012 CRC Press: Danvers, Massachusetts

2012-08-01T00:00:00Z Tsague, HD Nelwamondo, F Msimang, N http://hdl.handle.net/10204/6696 2013-04-18T21:55:18Z 2012-11-01T00:00:00Z

Title: An advanced mutual-authentication algorithm using 3DES for smart card systems Authors: Tsague, HD; Nelwamondo, F; Msimang, N Abstract: One of the most commonly used two-factor user authentication mechanisms nowadays is based on smart card and personal identity number or password. A scheme of this type is usually known as, a smart card based password authentication. The core feature of such a scheme is to enforce two-factor authentication in the sense that, the client must have the smart card and know the card PIN number in order to gain access to the server. In this paper, we propose and advanced remote mutual authentication scheme between a smart card, a smart card reader and the backend server database to ensure system security integrity. Our scheme provides high security and mutual authentication at a reasonable computational cost. Furthermore, it restricts most of the current attack mechanisms. It is simple and can be adapted to any kind of lightweight devices. Description: 2nd International Conference on Cloud and Green Computing (CGC 2012), Xiangtan, Hunan, China, 1-3 November 2012. To be published in IEEE Xpolre.

2012-11-01T00:00:00Z Long, CS Loveday, PW http://hdl.handle.net/10204/6686 2013-04-18T21:55:16Z 2012-09-01T00:00:00Z

Title: Numerical modelling of defects in rails Authors: Long, CS; Loveday, PW Abstract: The semi-analytical finite element (SAFE) method has become a popular tool for the analysis of elastic waveguides with complex cross-sections. We employ a recently developed hybrid SAFE-3D FE method to study the scattering of guided waves at discontinuities such as welds or cracks in continuous welded train rails. The aim of this particular study is to determine if it is possible to distinguish between scattering from welds and cracks for a given incident mode which is known to propagate long distance in rails. This study represents an initial step in the extension of the current ultrasonic broken rail detector (UBRD) system to detect cracks before complete breaks occur, which will require distinguishing between reflections from cracks and other reflectors such as welds, in order to avoid false alarms. Characterisation of transmission through welds is also useful for predicting the long-range attenuation of transducers in non-destructive evaluation (NDE) and monitoring systems, such as UBRD system developed by the Institute for Maritime Technology (IMT) and the Council for Scientific and Industrial Research (CSIR). Description: 8th South African Conference on Computational and Applied Mechanics (SACAM 2012), Johannesburg, South Africa, 3-5 September 2012

2012-09-01T00:00:00Z