Author:Onumanyi, Adeiza J; Abu-Mahfouz, Adnan MI; Hancke, GPDate:Jan 2021Parameter-based adaptive threshold estimators (ATEs) are widely used for signal detection in cognitive radio (CR) systems. However, their performance deteriorates under dynamic spectra conditions owing to a lack of valid methods to accurately ...Read more
Author:Makitla, I; Mtsweni, Jabu SDate:Dec 2015In this paper, we describe the development of a generalized metric for computing response time of a web service. Such a generalized metric would help to develop consensus with regards to the meanings of contracted Quality of Service (QoS) ...Read more
Author:Van Deventer, HeidiDate:Aug 2010The construction of linear developments, such as roads, railways, pipelines and power lines, in South Africa requires a number of alternatives to be considered prior to the submission of a proposed development for an Environmental Impact ...Read more
Author:Li, Y; Dudley, Angela L; Mhlanga, T; Escutia, MJ; Forbes, ADate:Aug 2013We experimentally generate non-diffracting vector vortex beams by using a Spatial Light Modulator (SLM) and an azimuthal birefringent plate (q-plate). The SLM generates scalar Bessel beams and the q-plate converts them to vector vortex beams. ...Read more
Author:Dudley, Angela L; Lib, Y; Mhlanga, T; Escuti, M; Forbes, ADate:Mar 2014We demonstrate how to create non-diffracting vector Bessel beams by implementing a spatial light modulator (SLM) to generate scalar Bessel beams which are then converted into vector fields by the use of an azimuthally-varying birefringent ...Read more
Author:Dudley, Angela L; Li, Y; Mhlanga, T; Escuti, M; Forbes, ADate:Sep 2013Nondiffracting vector Bessel beams are of considerable interest due to their nondiffracting nature and unique high-numerical-aperture focusing properties. Here we demonstrate their creation by a simple procedure requiring only a spatial light ...Read more
Author:Harmse, H; Britz, K; Gerber, ADate:Oct 2018A challenge in ontology engineering is the mismatch in expertise between the ontology engineer and domain expert, which often leads to important constraints not being specified. Domain experts often only focus on specifying constraints that ...Read more
Author:Carter, WS; Zunckel, M; Diab, RDate:Oct 2008Biomass burning is a source category that is often ignored in pollution dispersion modelling simulations. This study presents a unique contribution to the quantification of emissions from biomass burning for high resolution modelling. Previous ...Read more
Author:Alexander, B; Bollinger, JJ; Uys, HermannDate:Jun 2020Many quantum state preparation methods rely on a combination of dissipative quantum state initialization followed by unitary evolution to a desired target state. Here we demonstrate the usefulness of quantum measurement as an additional tool ...Read more
Author:Bell, Teboho; Ngcobo, Sandile; Haddadi, S; Ait-Ameur, K; Forbes, ADate:Jul 2015Using the digital laser one can generate various types of modes, like, Laguerre-Gaussian modes. The digital laser was forced to generate high-order radial Laguerre-Gaussian modes, LGp , with zero azimuthal order, by loading a digital hologram ...Read more
Author:Sayle, TXT; Catlow, CRA; Maphanga, RR; Ngoepe, PE; Sayle, DCDate:21 Sep 2005Models of MnO2 nanoparticles, with full atomistic detail, have been generated using a simulated amorphization and recrystallization strategy. In particular, a 25,000-atom "cube" of MnO2 was amorphized (tension-induced) under molecular dynamics ...Read more
Author:Botha, N; Botha, L; Du Plessis, A; Schwoerer, HDate:31 Aug 2010Femtosecond pulse shaping can be done by different kinds of pulse shapers, such as liquid crystal spatial light modulators (LC SLM), acousto optic modulators (AOM) and deformable and movable mirrors. A few applications where pulse shaping is ...Read more
Author:Vasilyeu, R; Dudley, Angela L; Khilo, N; Forbes, ADate:Oct 2009An experimental setup to generate a superposition of higher-order Bessel beams by means of a spatial light modulator and ring aperture is presented. The experimentally produced fields are in good agreement with those calculated theoretically.Read more
Author:Vasilyeu, R; Dudley, Angela L; Khilo, N; Forbes, ADate:Dec 2009The authors report the first experimental generation of the superposition of higher-order Bessel beams, by means of a spatial light modulator (SLM) and a ring slit aperture. They present illuminating a ring slit aperture with light which has ...Read more
Author:Forbes, A; Du Preez, N; Litvin, IA; Botha, LRDate:Jul 2009Generation and application of high power flattened Gaussian beams. Presented at the 54th Annual Conference of the South African Institute of Physics (SAIP) 2009.Read more
Author:Belyi, VN; Khilo, NA; Forbes, A; Ryzhevich, AADate:Aug 2009Linear and nonlinear processes of transferring optical singularities from anisotropic crystals onto the wavefront of Bessel light beams (BLBs) are investigated. The generation of high-order vortices at the propagation of BLBs along the optical ...Read more
Author:Kiarii, EM; Govender, Krishna; Ndungu, PG; Govender, PGDate:Apr 2017A systematic study of electronic and optical properties of titanium dioxide under visible light was simulated using the first principles calculations. Both electronic and optical properties were studied. The findings support the application ...Read more
Author:Hendriks, A; Naidoo, Darryl; Roux, FS; Löpez-Mariscal, C; Forbes, ADate:Aug 2012Phase-only spatial light modulators are now ubiquitous tools in modern optics laboratories, and are often used to generate so-called structured light. In this work we outline the use of a phase-only spatial light modulator to achieve full ...Read more
Author:Ngcobo, Sandile; Ait-Ameur, K; Forbes, ADate:Jul 2012This work deals with the generation of symmetrical high order Laguerre Gaussian modes. These high order Laguerre-Gaussian beams are generated by forcing the laser using an annular binary Diffractive Optical Element whose geometry is in ...Read more
Author:Bell, Teboho; Forbes, A; Ngcobo, SandileDate:Oct 2015The solid state digital laser was used in generation of Laguerre-Gaussian modes, LGpl, of different orders. This work demonstrates that we can generate high-order Laguerre-Gaussian modes with high purity using a digital laser.Read more