Callipo, A, Cucchiara, R & Piccardi, M 2000, 'Computational models for image processing for shared-memory multiprocessors', Integrated Computer-Aided Engineering, vol. 7, no. 1, pp. 39-52.
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Different tasks in image processing exhibit different computational requirements that should be considered with respect to the architecture. This is particularly critical in parallel machines where many parallelization techniques, as data partitioning an
Cucchiara, R, Grana, C, Piccardi, M & Prati, A 2000, 'Statistic and knowledge-based moving object detection in traffic scenes', ITSC2000. 2000 IEEE Intelligent Transportation Systems. Proceedings (Cat. No.00TH8493), pp. 27-32.
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Cucchiara, R, Piccardi, M & Mello, P 2000, 'Image analysis and rule-based reasoning for a traffic monitoring system', IEEE Transactions on Intelligent Transportation Systems, vol. 1, no. 2, pp. 119-130.
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The paper presents an approach for detecting vehicles in urban traffic scenes by means of rule-based reasoning on visual data. The strength of the approach is its formal separation between the low-level image processing modules (used for extracting visual data under various illumination conditions) and the high-level module, which provides a general-purpose knowledge-based framework for tracking vehicles in the scene. The image-processing modules extract visual data from the scene by spatio-temporal analysis during daytime, and by morphological analysis of headlights at night. The high-level module is designed as a forward chaining production rule system, working on symbolic data, i.e., vehicles and their attributes (area, pattern, direction, and others) and exploiting a set of heuristic rules tuned to urban traffic conditions. The synergy between the artificial intelligence techniques of the high-level and the low-level image analysis techniques provides the system with flexibility and robustness.
Cucchiara, R, Piccardi, M & Prati, A 2000, 'Hardware prefetching techniques for cache memories in multimedia applications', Proceedings Fifth IEEE International Workshop on Computer Architectures for Machine Perception, pp. 311-319.
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Guo, YJ, Vadgama, S & Tanaka, Y 2000, 'Advanced base station technologies for UTRAN', Electronics & Communication Engineering Journal, vol. 12, no. 3, pp. 123-132.
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To achieve high capacity and to support high-data-rate services in the terrestrial access network (UTRAN) of the third generation Universal Mobile Telecommunications System (UMTS), it is essential to employ some advanced transceiver techniques at the base stations. In this paper, three such techniques are presented: adaptive antennas, multistage parallel interference cancellers and a new hybrid scheme. The operation principles and some simulation results of the techniques are given and some challenging implementation issues are discussed.
Jia, D, Dutkiewicz, E & Chicharo, JF 2000, 'Performance analysis of QoS mechanisms in IP networks', Proceedings ISCC 2000. Fifth IEEE Symposium on Computers and Communications, pp. 359-363.
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Integrated services IP networks are expected to provide a variety of services with differentiated QoS. This requires the implementation of mechanisms that can discriminate service classes in terms of QoS. The IETF has recently proposed a Differentiated Services (Diffserv) framework for provision of QoS. In this paper we analyze performance of two Diffserv mechanisms: Threshold Dropping and Priority Scheduling in terms of packet loss and mean packet delay. A comparison of the two mechanisms is carried out with the requirement that both mechanisms provide the same level of packet loss for the preferred flow. This comparison extends the results reported in the literature for these two mechanisms. In particular, in this paper we determine the impact of buffer threshold and buffer size on packet loss and mean packet delay in these mechanisms.
Johnson, IR, Tellambura, C, Guo, YJ & Barton, SK 2000, 'HIPERLAN receiver design issues: noise performance and frequency offset compensation', International Journal of Wireless Information Networks, vol. 7, no. 1, pp. 29-41.
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This paper is concerned with some physical layer issues for HIPERLAN. First, the noise performance required of each class of receivers in HIPERLAN is determined. Secondly, the effect of frequency offset on the performance of equalisers is investigated and various techniques for joint equalisation and frequency offset compensation are studied. It is shown that by employing a decision feedback equaliser incorporating a second order phase locked loop, the effect of both the intersymbol interference and frequency offset can be significantly reduced. Using such a technique, the packet error ratio (PER) of a HIPERLAN radio link in a multipath channel is found by simulation.
Mengkang Peng, Sasabo, MF, Hingjie Jay Guo, Downing, OJ & Barton, SK 2000, 'Frame-extended linear decorrelating detector for asynchronous CDMA', IEEE Transactions on Vehicular Technology, vol. 49, no. 5, pp. 1918-1927.
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Missiroli, M, Yingjie Jay Guo & Barton, SK 2000, 'Near-far resistant channel estimation for CDMA systems using the linear decorrelating detector', IEEE Transactions on Communications, vol. 48, no. 3, pp. 514-524.
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The well-known linear decorrelating detector (LDD) for direct-sequence code-division multiple-access (CDMA) systems provides near-far resistant performance when the timing of each user is accurately known. Traditional CDMA acquisition techniques suffer from high differences in power levels. The estimation accuracy for a user overwhelmed by stronger ones is likely to be unsatisfactory; at the same time, the interference from a user undergoing acquisition or tracking is not removed by the standard LDD. In this paper, a fully near-far resistant technique for acquisition and tracking for asynchronous CDMA systems applying the LDD is proposed, considering realistic band-limited signals. This technique is based on the adoption of a pair of special sequences equivalent to a dedicated access channel and is shown to provide a relatively fast and robust means to perform channel estimation both in case of single- and multipath channels.
Parfitt, AJ & Bird, TS 2000, 'Phased array antenna analysis using time delay beam steering and hybrid FDTD method', Electronics Letters, vol. 36, no. 2, pp. 108-108.
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Raad, RS, Dutkiewicz, E & Chicharo, J 2000, 'Connection admission control in micro-cellular multi-service mobile networks', Proceedings ISCC 2000. Fifth IEEE Symposium on Computers and Communications, pp. 600-606.
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This paper investigates the use of fixed bandwidth reservation for Multi-service mobile networks. In particular it extends previous fixed Multi-service network results to the mobile scenario and presents analytical and simulation results for new and handover call blocking probabilities. It also investigates the performance sensitivity to different traffic load ratios as well as the cell dwell time distribution.
Roughan, R, Veitch, D & Abry, P 2000, 'Real-time estimation of the parameters of long-range dependence', IEEE/ACM Transactions on Networking, vol. 8, no. 4, pp. 467-478.
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Veitch, D, Taqqu, MS & Abry, P 2000, 'Meaningful MRA initialization for discrete time series', Signal Processing, vol. 80, no. 9, pp. 1971-1983.
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Zhang, J, Arnold, JF & Frater, MR 2000, 'A cell-loss concealment technique for MPEG-2 coded video', IEEE Transactions on Circuits and Systems for Video Technology, vol. 10, no. 4, pp. 659-665.
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Audio-visual and other multimedia services are seen as important sources of traffic for future telecommunication networks, including wireless networks. A major drawback with some wireless networks is that they introduce a significant number of transmissi
Bangun, RA & Dutkiewicz, E 1970, 'Modelling multi-player games traffic', Proceedings International Conference on Information Technology: Coding and Computing (Cat. No.PR00540), International Conference on Information Technology: Coding and Computing. ITCC 2000, IEEE Comput. Soc, pp. 228-233.
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The growing popularity of delay-sensitive multi-player games over the Internet is creating a need for proper characterisation of such traffic. We are currently developing source models for game traffic, on a per-player basis, with the intended use being to scale the models to simulate scenarios involving large numbers of players, which will enable us to observe the effects of game traffic on the network. We outline the procedure used, and we show that for certain cases, relatively simple source models are able to provide sufficiently accurate results (in terms of mean delay and mean buffer occupancy).
Chainais, P, Abry, P & Veitch, D 1970, 'Multifractal analysis and α-stable processes: a methodological contribution', 2000 IEEE International Conference on Acoustics, Speech, and Signal Processing. Proceedings (Cat. No.00CH37100), 2000 International Conference on Acoustics, Speech and Signal Processing, IEEE, IEEE, pp. 241-244.
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Cucchiara, R, Piccardi, M & Prati, A 1970, 'Focus based Feature Extraction for Pallets Recognition', Procedings of the British Machine Vision Conference 2000, British Machine Vision Conference 2000, British Machine Vision Association.
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Rao, N, Parfitt, A, Dadello, A, Ward, D & Bird, T 1970, 'A Low Noise Ka-Band Down Converter for Space Applications', 30th European Microwave Conference, 2000, 30th European Microwave Conference, 2000, IEEE.
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A Ka-band down converter has been developed for use in a transponder to be flown on board a Low Earth Orbiting (LEO) satellite called Fedsat. The down converter employs a single Monolithic Microwave Integrated Circuit (MMIC) which combines the functions of a low noise amplifier and a mixer. The down converter unit has been designed with a particular emphasis on the choice of right materials, components, packaging and assembly techniques with a goal to achieve a low cost unit qualified for space environment. © 2000 IEEE.
Veitch, D, Abry, P, Flandrin, P & Chainais, P 1970, 'Infinitely divisible cascade analysis of network traffic data', 2000 IEEE International Conference on Acoustics, Speech, and Signal Processing. Proceedings (Cat. No.00CH37100), 2000 International Conference on Acoustics, Speech and Signal Processing, IEEE, IEEE, pp. 245-248.
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Ware, C, Judge, J, Chicharo, J & Dutkiewicz, E 1970, 'Unfairness and capture behaviour in 802.11 adhoc networks', 2000 IEEE International Conference on Communications. ICC 2000. Global Convergence Through Communications. Conference Record, IEEE International Conference on Communications, IEEE, pp. 159-163.
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In this paper we address issues with the performance of IEEE 802.11, when used in the adhoc mode, in the presence of hidden terminals. We present results illustrating the strong dependence of channel capture behavior on the SNR observed on contending hidden connections. Experimental work has illustrated that in a hidden terminal scenario, the connection having the strongest SNR is able to capture the channel, despite the use of the RTS-CTS-DATA-ACK 4-way handshake designed to alleviate this problem. Our results indicate that the near-far SNR problem may have a significant effect on the performance of an adhoc 802.11 network.
Yunxin Li & Xiaojing Huang 1970, 'The generation of independent Rayleigh faders', 2000 IEEE International Conference on Communications. ICC 2000. Global Convergence Through Communications. Conference Record, IEEE International Conference on Communications, IEEE, New Orleans, USA, pp. 41-45.
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The simulation of wireless communication channels often requires the generation of multiple complex waveforms satisfying the following conditions. 1) The real and imaginary parts are independent zero-mean random Gaussian processes with identical auto-correlation functions. 2) The complex waveforms are independent so that the cross-correlation function between any two waveforms is zero. In this paper, we first analyze previously proposed methods based on Jakes fading model to demonstrate that the above two conditions have not been satisfied. We then propose a novel method for the generation of multiple Rayleigh faders, which uses improved arrival angle patterns and incident wave phases. The auto-correlation and cross-correlation functions are derived to prove theoretically that the above two conditions are satisfied. Finally the statistical properties are verified by numerical results.
