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IEE Proceedings I - Communications, Speech and Vision

Issue 6 • Dec. 1992

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Displaying Results 1 - 11 of 11
  • Measurements of vocal tract shapes using magnetic resonance imaging

    Publication Year: 1992, Page(s):553 - 560
    Cited by:  Papers (5)  |  Patents (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (789 KB)

    Magnetic resonance imaging is used to determine the vocal tract area functions of a speaker producing five steady vowel sounds. The data is used in an account tube model, formed by concatenating short uniform sections, and the acoustic spectra of the computed output from the model are compared with those of natural speech. For all but one of the vowels good agreement (typically within 120 Hz) is o... View full abstract»

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  • 3-D object recognition using fuzzy quaternions

    Publication Year: 1992, Page(s):561 - 568
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (533 KB)

    A new discrimination method based on fuzzy subset theory is proposed. This approach uses Zernike moment invariants of the silhouette of the unknown object to form a set of fuzzy-weighted quantities called fuzzy quaternions. These are matched against those of known objects at predetermined viewpoints. To speed up the recognition process, a modified simplex version of the Nelder-Mead algorithm is ut... View full abstract»

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  • Using predicted irradiation profiles to extract shape information from infrared images

    Publication Year: 1992, Page(s):569 - 574
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (544 KB)

    The author addresses the problem of infrared image formation and derive an irradiation equation for simple infrared scenes. He considers the complications caused by mutual illumination of one or more bodies and indicates how the infrared irradiation equation can also be specified for more complex scenes. The infrared irradiation equation is solved in closed form for some simple geometries for both... View full abstract»

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  • Low bit-rate image sequence coding using spatial decomposition

    Publication Year: 1992, Page(s):575 - 581
    Cited by:  Papers (7)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (733 KB)

    The technique described has been developed from the still-picture version of the recursive binary nesting algorithm to code moving image sequences efficiently at low bit rates. The technique, based on quadtree decomposition and spatial interpolation had to be modified from its previous form so that it could make use of the additional time-axis redundancy available in a moving sequence, and also to... View full abstract»

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  • Word-based dynamic algorithms for data compression

    Publication Year: 1992, Page(s):582 - 586
    Cited by:  Papers (10)  |  Patents (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (386 KB)

    A new algorithm, word-based dynamic Lempel-Ziv (WDLZW) for universal (lossless) data compression, is introduced. The novel feature is that the algorithm is optimised for the compression of natural language data, in which all the spaces between words are deleted whenever copy codes or literal codes are sent out. Therefore better compression rates can be achieved. The algorithm can still compress al... View full abstract»

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  • Hermite polynomials for signal reconstruction from zero-crossings. 1. One-dimensional signals

    Publication Year: 1992, Page(s):587 - 596
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (870 KB)

    Generalised Hermite polynomials are employed for the reconstruction of an unknown signal from a knowledge of its zero-crossings, under certain conditions on its spatial/spectral width, but dispensing with the assumption of bandlimitedness. A computational implementation of the proposed method is given for one-variable (or one-dimensional) signals, featuring an application of simulated annealing fo... View full abstract»

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  • Maximum-likelihood synchronisation algorithms for Q/sup 2/PSK

    Publication Year: 1992, Page(s):597 - 606
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (827 KB)

    New maximum-likelihood synchronisation algorithms for quadrature-quadrature phase shift keying (Q/sup 2/PSK) signals are presented and evaluated. A brief description of the Q/sup 2/PSK modulation scheme is given. The digital implementation of the algorithms used in the simulation of a constant-envelope Q/sup 2/PSK modem system and their computational loads are presented. Bit error rate performance... View full abstract»

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  • A packet reservation multiple access protocol for integrated speech and data transmission

    Publication Year: 1992, Page(s):607 - 612
    Cited by:  Papers (42)  |  Patents (5)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (516 KB)

    The authors propose an 'integrated packet reservation multiple access' (IPRMA) protocol for transmitting both speech and data information. While speech users are allowed to contend for reservation slots on a frame-by-frame basis, data users may reserve multiple slots across a frame to increase throughput. The protocol includes a priority mechanism which ensures that speech users have greater acces... View full abstract»

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  • Busy code broadcasting and sensing protocol for collision-free CDMA packet radio networks and its performance analysis

    Publication Year: 1992, Page(s):613 - 619
    Cited by:  Papers (5)  |  Patents (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (604 KB)

    To relieve the contention in packet initiations in CDMA packet radio networks, a novel protocol, the busy code broadcasting and sensing protocol, is proposed, and its steady-state throughput-delay performance upper bounds are numerically analysed. The results reveal that a high throughput of about 0.47 (when the normalised channel traffic r=1) and a stable performance of the network can be achieve... View full abstract»

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  • Monte Carlo simulation of direct sequence spread spectrum for indoor radio communication in a Rician fading channel

    Publication Year: 1992, Page(s):620 - 624
    Cited by:  Papers (8)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (345 KB)

    A Monte Carlo simulation was conducted to assess the performance, in terms of bit error probability, of a direct sequence spread spectrum multiple access (DS/SSMA) radio system in indoor Rician fading channels using differential phase shift keying (DPSK). Simulation results are presented for a DS/SSMA indoor ratio system using selection diversity. Importance sampling techniques were used to accele... View full abstract»

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  • Optimal virtual circuit routing in computer networks

    Publication Year: 1992, Page(s):625 - 632
    Cited by:  Papers (4)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (575 KB)

    Routing for virtual circuit mode services has been identified as a multicommodity network flow problem, and proves to be at least as hard as NP-complete problems. This paper proposes two approaches to this problem. The first is simulated annealing which is known to be time-consuming but suitable to probe the global optimum of combinatorial problems. An annealing method might not be practical to im... View full abstract»

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