Publications

Gerber, R & Braun, R 1998, New Connections Telecommunications in a Changing South Africa, University of Cape Town Press (ZA).
View description>>

Written for students as well as business managers in telecommunications industries, this book investigates the telecommunications sector worldwide, and includes a detailed study of the South African perspective.

Abry, P & Veitch, D 1998, 'Wavelet analysis of long-range-dependent traffic', Information Theory, IEEE Transactions on, vol. 44, pp. 2-15.

Abry, P, Veitch, D & Flandrin, P 1998, 'Long-range Dependence: Revisiting Aggregation with Wavelets', Journal of Time Series Analysis, vol. 19, pp. 253-266.

Aslund, M, Canning, J & Bazylenko, M 1998, 'High-temperature stable gratings in germanosilicate planar waveguides', OPTICS LETTERS, vol. 23, no. 24, pp. 1898-1900.
View/Download from: Publisher's site

Auzanneau, F & Ziolkowski, RW 1998, 'Microwave signal rectification using artificial composite materials composed of diode-loaded electrically small dipole antennas', IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, vol. 46, no. 11, pp. 1628-1637.
View/Download from: Publisher's site

Auzanneau, F & Ziolkowski, RW 1998, 'Theoretical study of synthetic bianisotropic materials', JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS, vol. 12, no. 3, pp. 353-370.
View/Download from: Publisher's site

Bateman, D, Bird, T & Sanagavarapu, AM 1998, 'Asymptotic Approximation Of Some Integrals Involved In Efie Solutions Using The Method Of Moments', IEE Proceedings-microwaves Antennas And Propagation, vol. 145, no. 4, pp. 361-365.
View/Download from: Publisher's site
View description>>

It is well known that, in electromagnetic-field analysis using the method of moments, the matrix-filling time can dominate the total solution time. Therefore, having an efficient means of calculating the elements of the matrix is important. Asymptotic an

Bazylenko, MV, Moss, D & Canning, J 1998, 'Complex photosensitivity observed in germanosilica planar waveguides', OPTICS LETTERS, vol. 23, no. 9, pp. 697-699.
View/Download from: Publisher's site

Butchart, K & Braun, RM 1998, 'An adaptive modulation scheme for low earth orbit satellites', PROCEEDINGS OF THE 1998 SOUTH AFRICAN SYMPOSIUM ON COMMUNICATIONS AND SIGNAL PROCESSING, pp. 43-46.
View/Download from: Publisher's site

Canning, J & Moss, D 1998, 'Grating-based transmission bandpass filters using dispersion-matched mode conversion', OPTICS LETTERS, vol. 23, no. 3, pp. 174-176.
View/Download from: Publisher's site

Canning, J, Moss, D, Aslund, M & Bazylenko, M 1998, 'Negative index gratings in germanosilicate planar waveguides', ELECTRONICS LETTERS, vol. 34, no. 4, pp. 366-367.
View/Download from: Publisher's site

Cucchiara, R, Neri, G & Piccardi, M 1998, 'A Real-time Hardware Implementation Of The Hough Transform', Journal Of Systems Architecture, vol. 45, no. 1, pp. 31-45.
View/Download from: Publisher's site
View description>>

The paper presents a hardware implementation of algorithms based on the Hough transform (HT) for real-time straight line detection. In particular, the basic HT on the edge points (EHT) and the Gradient-Weighted Hough transform (GWHT) for gray-level image

Cuthbert, J & Braun, RM 1998, 'Selection Of Multi-h Modulation Sets Using A Stochastic Search Algorithm', IEE Proceedings-communications, vol. 145, no. 1, pp. 41-46.
View/Download from: Publisher's site
View description>>

Multi-h CPFSK modulation is simple to implement, spectrally efficient, and has inherent error correction properties. Multi-h requires large parameter sets to obtain high coding gain. Large numbers of combinations may need to be investigated. A fast effic

Dvorak, SL, Ziolkowski, RW & Felsen, LB 1998, 'Hybrid analytical-numerical approach for modeling transient wave propagation in Lorentz media', JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION, vol. 15, no. 5, pp. 1241-1255.
View/Download from: Publisher's site

He, S, Hintz, TB & Szewcow, U 1998, 'Replicated Shared Object Model For Edge Detection With Spiral Architecture', Parallel And Distributed Processing, vol. 1388, pp. 252-260.
View description>>

Edge detection in computer vision and image processing is a process which detects one kind of significant features appearing as discontinuities in intensities. A parallel edge detection algorithm based on Spiral Architeture is designed in this paper by a

He, S, Hintz, TB & Szewcow, U 1998, 'Replicated Shared Object Model For Parallel Edge Detection Algorithm Based On Spiral Architecture', Future Generation Computer Systems, vol. 14, no. 5-6, pp. 341-350.
View/Download from: Publisher's site
View description>>

Edge detection in computer vision and image processing is a process which detects one kind of significant feature in an image that appears as discontinuities in intensities. A parallel edge detection algorithm based on spiral architecture is designed in

HILDING, JAIM & VEITCH, D 1998, 'UNDERSTANDING END-TO-END INTERNET TRAFFIC DYNAMICS.', GLOBECOM..., pp. 1118-1118.

HILDING, JAIM & VEITCH, D 1998, 'UNDERSTANDING END-TO-END INTERNET TRAFFIC DYNAMICS.', GLOBECOM..., pp. 1118-1118.

Keenan, T, Glasson, K, Cummings, F, Bird, TS, Keeler, J & Lutz, J 1998, 'The BMRC/NCAR C-band polarimetric (C-POL) radar system', JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY, vol. 15, no. 4, pp. 871-886.
View/Download from: Publisher's site

Keenan, T, Glasson, K, Cummings, F, Bird, TS, Keeler, J & Lutz, J 1998, 'The BMRC/NCAR C-band polarimetric (C-POL) radar system', Journal of Atmospheric and Oceanic Technology, vol. 15, no. 4, pp. 871-886.
View/Download from: Publisher's site
View description>>

The development of the first Australian C-band polarimetric/Doppler meteorological radar system (C-POL) is described. Motivated by the need to obtain improved rainfall estimation and the vertical profile of hydrometeors, C-POL was developed jointly by the Bureau of Meteorology (BOM), the Commonwealth Scientific and Industrial Research Organisation of Australia, and the National Center for Atmospheric Research. C-POL is based on a standard operational C-band radar employed by the BOM but modified to be capable of transmitting linear horizontal and vertical polarizations and receiving the co- and cross polarizations on a pulse-to-pulse basis. Standard variables extracted include horizontal reflectivity (ZHH), radial velocity (Vr), spectral width (συ), differential reflectivity (ZDR), differential phase shift (ΦDP), and zero lag correlation coefficient [ρHV(0)]. With the addition of a second receiver chain, the linear depolarization ratio will soon be available. Initial results with the radar are discussed to give examples of the data quality, as well as some of the problems inherent in using a C-band radar in the Tropics.

Liang, T & Ziolkowski, RW 1998, 'Dispersion effects on grating-assisted output couplers under ultrafast pulse excitations', MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, vol. 17, no. 1, pp. 17-23.
View/Download from: Publisher's site

Liang, T & Ziolkowski, RW 1998, 'Grating assisted waveguide-to-waveguide couplers', IEEE PHOTONICS TECHNOLOGY LETTERS, vol. 10, no. 5, pp. 693-695.
View/Download from: Publisher's site

Liang, T & Ziolkowski, RW 1998, 'Grating assisted waveguide-to-waveguide couplers', IEEE Photonics Technology Letters, vol. 10, no. 3, pp. 693-695.
View description>>

A new radiation-type waveguide-to-waveguide coupler is proposed. The coupling is realized through gratings embedded on the dielectric waveguides involved. Compared to the conventional hybrid-mode coupler, this type of coupler has advantages in that the two waveguides can be quite dissimilar as well as being separated by large distances. It is demonstrated that the coupling performance of this radiation-type coupler can be enhanced significantly by using photonic bandgap (PBG) structures.

Liang, T & Ziolkowski, RW 1998, 'Ultrafast pulsed mode effects on the performance of grating-assisted output couplers of finite extent', OPTICS LETTERS, vol. 23, no. 6, pp. 469-471.
View/Download from: Publisher's site

Oughstun, KE & Ziolkowski, RW 1998, 'Mathematics and modeling in modern optics', JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION, vol. 15, no. 5, pp. 1238-1238.
View/Download from: Publisher's site

Parfitt, AJ & Bird, TS 1998, 'Computation of aperture antenna mutual coupling using FDTD and Kirchhoff field transformation', ELECTRONICS LETTERS, vol. 34, no. 12, pp. 1167-1168.
View/Download from: Publisher's site

Saban, D & Braun, RM 1998, 'Multi-carrier direct sequence CDMA in fading situations', PROCEEDINGS OF THE 1998 SOUTH AFRICAN SYMPOSIUM ON COMMUNICATIONS AND SIGNAL PROCESSING, pp. 33-38.
View/Download from: Publisher's site

Saban, G & Braun, RM 1998, 'Wireless local loop and packet radio technology for developing communities', PROCEEDINGS OF THE 1998 SOUTH AFRICAN SYMPOSIUM ON COMMUNICATIONS AND SIGNAL PROCESSING, pp. 1-6.
View/Download from: Publisher's site

Seaman, B & Braun, RM 1998, 'Using cyclostationarity in the modulation classification of analogue signals', PROCEEDINGS OF THE 1998 SOUTH AFRICAN SYMPOSIUM ON COMMUNICATIONS AND SIGNAL PROCESSING, pp. 261-266.
View/Download from: Publisher's site

Tellambura, C, Guo, YJ & Barton, SK 1998, 'Channel estimation using aperiodic binary sequences', IEEE Communications Letters, vol. 2, no. 5, pp. 140-142.
View/Download from: Publisher's site
View description>>

Estimating a channel impulse response using a known aperiodic sequence is considered. The problem can be reduced to minimizing the trace of the inverse of a Toeplitz matrix. An efficient algorithm for computing this trace is developed and optimal binary sequences up to length 32 are found and tabulated. The use of complementary sequences in this context is also investigated. It is shown that the eigenvalues of the autocorrelation matrices of a pair of complementary sequences sum to a known constant.

Ziolkowski, RW & Gogny, DM 1998, 'Cavity modifications of nuclear internal conversion rates – abstract', Journal of Electromagnetic Waves and Applications, vol. 12, no. 5, pp. 675-676.
View/Download from: Publisher's site
View description>>

We extend the principles of cavity quantum electrodynamics to nuclei inside low-loss cavities. The resulting nucleus-cavity system exhibits spontaneous emission and internal conversion rates which differ radically from those of the individual components. The quantum mechanical derivations of these rates are given. The internal conversion process occurs via the exchange of a virtual photon between an excited nucleus and an electron bound to that nucleus. Even though the photon is virtual, partial suppression of the internal conversion process is shown to be theoretically possible. With a controlled modification of the internal conversion rate using a high- Q cavity, one can achieve a number of potentially interesting applications including an excited nuclear state containment unit, a nuclear battery, and a neutron detector. © Journal of Electromagnetic Waves and Applications. All rights reserved.

Andren, J, Hilding, M & Veitch, D 1998, 'Understanding end-to-end internet traffic dynamics', Global Telecommunications Conference, 1998. GLOBECOM 1998. The Bridge to Global Integration. IEEE, IEEE, pp. 1118-1122.

Banh, BAJ, Anido, GJ & Dutkiewicz, E 1998, 'Handover re-routing schemes for connection oriented services in mobile ATM networks', Proceedings - IEEE INFOCOM, pp. 1139-1146.
View description>>

Wireless ATM (WATM) will be used to support broadband applications for future generation mobile services. To achieve this, the existing ATM protocol must be augmented with mobility management capabilities. One of the important components of mobility management is the ability of the network to seamlessly re-route existing connections to different parts of the network. To date, a number of schemes have been proposed for broadband wireless networks. These schemes can potentially be used in WATM networks. In this paper, we compare the performance of these schemes in terms of their complexity, handover latency, communication disruption period and buffer and bandwidth requirements.

Barattin, M, Cucchiara, R & Piccardi, M 1998, 'A Rule-based Vehicular Traffic Tracking System', Proceedings of the Joint Conference on Information Sciences, pp. 334-337.
View description>>

The paper presents a computer vision-based approach to the problem of vehicular traffic monitoring. The approach associates a high-level tracking system to a low-level system that performs moving vehicles detection. The high-level module is based on a large set of rules and is able to keep tracks of all moving or stopped vehicles along the image sequence.

Bird, TS 1998, 'Recent progress in reflector antenna analysis & design', Symposium on Antenna Technology and Applied Electromagnetics, ANTEM 1998 - Conference Proceedings, 1998 Symposium on Antenna Technology and Applied Electromagnetics, IEEE, Ottawa, Canada, pp. 3-6.
View/Download from: Publisher's site
View description>>

© 1998 IEEE. The latter part of the 20th century has seen significant changes and improvements in the design and practice of reflectorantennas. As well as traditional users of reflectors, such as defence, telecommunication utilities and radio astronomy, significant consumer markets have now opened up. For instance, it is common for many homes and offices to have a dish connected to a wall or roof. At the same time design techniques for reflectors and associated feed systems have also undergone change. Until a few years ago effectsthat were poorly modelled or completely ignored that can now be analysed include, reflectoredge diffraction, near-field effects, grid, composite and painted surfaces, accurate feed models, mutual coupling and scattering in feed arrays, and reflector/feedinteractions. Shaped reflectors are now widely used on satellite antennas, and dielectric-loaded horns are replacing corrugated horns in some earth station applications. It is the purpose here to outline some recent changes and improvements in the design and synthesis techniques used for reflectors and feeds.

Canning, J, Sceats, MG & Carter, ALG 1997, 'UV-induced structural changes in photosensitive optical fibres', JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS, International Workshop on Structure and Functional Optical Properties of Silica and Silica-Related Glasses, JAPAN SOC APPLIED PHYSICS, TOYOTA MOTOR CORP, MIKKABI CREAT CTR, SHIZUOKA, JAPAN, pp. 59-61.
View/Download from: Publisher's site

Cucchiara, R & Piccardi, M 1998, 'Exploiting image processing locality in cache pre-fetching', FIFTH INTERNATIONAL CONFERENCE ON HIGH PERFORMANCE COMPUTING, PROCEEDINGS, 5th International Conference on High Performance Computing, IEEE COMPUTER SOC, CHENNAI, INDIA, pp. 466-472.
View/Download from: Publisher's site

Guo, YJ, Vadgama, S, Davies, M, Khalab, J, Zarri, M & Spink, D 1998, 'Adaptive antenna for CDMA', IEEE International Symposium on Spread Spectrum Techniques & Applications, pp. 590-594.
View description>>

A decision directed adaptive antenna array for the uplink of CDMA cellular systems, which is based on a normalized least mean square algorithm (NLMS), is presented. The bit error ratio performance of the adaptive antenna in various scenarios, which include the use of transmission power control (TPC) and diversity combining, is studied. It is shown that the adaptive antenna outperforms the steering beam technique when the signal-to-noise ratio is large and the active users are clustered. However, the performance of the adaptive antenna becomes very similar to that of the steering beam when there are a large number of randomly distributed active users in the sector.

Liu, RP, Richards, A & Rogers, G 1998, 'MARSHNet, a superimposed QoS guaranteed Virtual Path Network', GLOBECOM 98: IEEE GLOBECOM 1998 - CONFERENCE RECORD, VOLS 1-6, IEEE Global Telecommunications Conference (GLOBECOM 98), IEEE, SYDNEY, AUSTRALIA, pp. 7-12.

Moss, D, Canning, J & Bazylenko, M 1998, 'Bragg gratings in hollow-cathode PECVD germanosilica planar waveguides', Conference on Lasers and Electro-Optics Europe - Technical Digest, p. 425.
View/Download from: Publisher's site
View description>>

Waveguide gratings were fabricated in intrinsically low-loss (0.2 dB/cm with no annealing) germanosilica waveguide layers without the use of any material presensitization. The waveguides were grown by a novel technique called hollow-cathode PECVD.

Partilt, AJ & Bird, TS 1998, 'Application of a near-field transform algorithm to antenna coupling using the FDTD method', IEEE Antennas and Propagation Society International Symposium, 1998 Digest - Antennas: Gateways to the Global Network - Held in conjunction with: USNC/URSI National Radio Science Meeting, pp. 500-503.
View/Download from: Publisher's site
View description>>

© 1998 IEEE. The finite-difference time-domain (FDTD) method is useful in many antenna applications because it facilitates modelling of complex structures and is capable of characterising antenna performance over a wide-frequency band. However, for antenna arrays of even modest size, the excessive computer storage and run-time may become prohibitive for design and optimisation purposes. Some work has been done with time-domain transform methods for computing weak coupling between antennas (Page et al. 1996). In this paper, an algorithm is developed using the Kirchhoff near-field to near-field transformation (Shlager and Smith, 1995) for the one-way coupling between antenna elements. This coupling representation is then applied to arrays in a manner analogous to an element-by-element analysis in the frequency domain, except that in the method described here the coupled currents at the antenna-feed ports are added in the time-domain so as to permit the introduction of true-time delays for wide-band beam steering. The advantages of the transform method over a full FDTD method are smaller computer storage and a reduction in late-time FDTD effects associated with reflections from the absorbing boundary on the outer surface of the computational domain and also from numerical dispersion and instabilities.

Roughan, M, Veitch, D & Abry, P 1998, 'On-line estimation of the parameters of long-range dependence', GLOBECOM 98: IEEE GLOBECOM 1998 - CONFERENCE RECORD, VOLS 1-6, IEEE Global Telecommunications Conference (GLOBECOM 98), IEEE, SYDNEY, AUSTRALIA, pp. 3716-3721.

Roughan, M, Veitch, D & Rumsewicz, M 1998, 'Computing queue-length distributions for power-law queues', INFOCOM’98. Seventeenth Annual Joint Conference of the IEEE Computer and Communications Societies. Proceedings. IEEE, IEEE, pp. 356-363.

Stepanov, DY, Canning, J & Brodzeli, Z 1998, 'High-resolution measurements of fibre Bragg grating transmission spectra', 24TH EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION, VOL 1-3, 24th European Conference on Optical Communications, TELEFONICA ESPANA SA, MADRID, SPAIN, pp. 407-408.

Tellambura, C, Parker, MG & Barton, SK 1998, 'Channel estimation using discrete Fourier transform techniques', GLOBECOM 98: IEEE GLOBECOM 1998 - CONFERENCE RECORD, VOLS 1-6, IEEE Global Telecommunications Conference (GLOBECOM 98), IEEE, SYDNEY, AUSTRALIA, pp. 148-152.

von Bibra, ML, Canning, J & Roberts, A 1997, 'Mode profile modification of H+ ion beam irradiated waveguides using UV processing', JOURNAL OF NON-CRYSTALLINE SOLIDS, Glass and Optical Materials Division / Bragg Gratings, Photosensitivity and Poling in Glass Fibers and Waveguides - Applications and Fundamentals Meeting, ELSEVIER SCIENCE BV, WILLIAMSBURG, VIRGINIA, pp. 121-125.
View/Download from: Publisher's site

Ziolkowski, RW 1998, 'Finite photonic band gap material based waveguides, power splitters and switches', IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM - ANTENNAS: GATEWAYS TO THE GLOBAL NETWORK, VOLS 1-4, IEEE Antennas-and-Propagation-Society International Symposium on Antennas - Gateways to the Global Network, IEEE, ATLANTA, GA, pp. 873-873.