http://hdl.handle.net/10204/916 Wed, 19 Jun 2013 23:20:16 GMT 2013-06-19T23:20:16Z http://hdl.handle.net/10204/6704 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 Wed, 01 Aug 2012 00:00:00 GMT http://hdl.handle.net/10204/6704 2012-08-01T00:00:00Z http://hdl.handle.net/10204/6562 Title: Linear elastic analysis of pavement structure under non-circular loading Authors: Maina, JW; Ozawa, Y; Matsui, K Abstract: Conventional methods for road and airport pavement analyses, such as BISAR and GAMES, were developed based on a cylindrical coordinate system. Because of the loading symmetry due to the assumption that a circular uniformly distributed load is acting on the pavement surface, it was useful to use a cylindrical coordinate system. However, depending on the magnitude of the tire load, several research reports on tire–pavement contact stresses have shown that the contact patch is predominantly rectangular and not circular in shape. Based on this observation and the fact that it may be difficult for most multi-layer linear elastic software packages to make use of the field measured tire–pavement contact stresses, which are rectangular in shape, this paper presents the development of a method for pavement structural analysis considering both uniform and non-uniform loads acting over a rectangular area. In this approach, three components of displacements, which satisfy Navier’s equations, are expressed using Neuber-Papkovich functions.Worked examples for vertical and horizontal loads acting over rectangular area are presented in this paper. In order to verify the validity of the solutions obtained, the results are compared with those obtained from freeware GAMES software, which analyses loads acting over a circular area and is widely used in Japan and South Africa and a number of institutions in Australia, Europe and US. Description: Copyright: 2012 Taylor and Francis. This is an ABSTRACT ONLY. The definitive version s published in Road Materials and Pavement Design, vol. 13(3), pp 403-421. http://dx.doi.org/10.1080/14680629.2012.705419 Mon, 01 Oct 2012 00:00:00 GMT http://hdl.handle.net/10204/6562 2012-10-01T00:00:00Z http://hdl.handle.net/10204/6378 Title: Hardware in the loop radar environment simulation on wideband DRFM platforms Authors: Strydom, JJ; Cilliers, JE; Gouws, M; Naicker, D; Olivier, K Abstract: This paper describes the development and testing of a digital radio frequency memory (DRFM) kernel, as well as some of the functionality which has been added to the system to make it a fully-fledged hardware in the loop (HIL) radar environment simulator (RES) system for radar testing and evaluation. Description: Copyright: 2012 IET. First published at IET Radar Conference, Glasgow, United Kingdom, 23-25 October 2012 Mon, 01 Oct 2012 00:00:00 GMT http://hdl.handle.net/10204/6378 2012-10-01T00:00:00Z http://hdl.handle.net/10204/6352 Title: Achievable capacity design for irregular and clustered high performance mesh networks Authors: Olwal, TO; Masonta, MT Abstract: This study has presented the End to End (E2E) upper bound capacity limits for high performance mesh nodes that can be deployed in rural and remote areas. The achievable capacity limits for both irregular and clustered placements of nodes have been analytically derived. Numerical results based on the data sheets of IEEE 802.11a/n standards reveal the efficacy of such designs to typical rural networks such as the Peebles valley mesh in rural South Africa. Description: AFRICOMM 2012 Conference, Yaounde, Cameroon, 12-14 November 2012 Thu, 01 Nov 2012 00:00:00 GMT http://hdl.handle.net/10204/6352 2012-11-01T00:00:00Z