In this paper, we investigate the use of the switched split vector quantiser (SSVQ) for coding short-term spectral envelope information for wideband speech coding. The SSVQ is the hybrid of a switch vector quantiser and split vector quantiser, which has been shown in previous studies to be more efficient, in terms of rate-distortion, as well as possessing low computational complexity, than the ...

In this paper, we describe a novel approach to image quantisation by using a genetic algorithm to find near-optimal code words. Moving away from the traditional binary string representations of genetic data, the proposed system applies genetic operators directly on pixel blocks thus avoiding any conversion to a conventional format. To operate on the data this way, operators for fitness, combina...

Generally characteristic of speech waveform is the continuous signal, which contains of voiced and unvoiced signal. Historically, speech waveform is coded by dividing it into frames; it is typically divided into 30 ms frame length, where each frame is coded separately. Speech is however created by a physical system and is substantially shaped by the vocal tract. As it is physically impossible f...

McGurk and MacDonald (Nature 264, 746-748, 1976) discovered that when a discrepancy is created between visual information from lip movements and speech information from the auditory channel then perceivers often report a percept that is neither the auditory or visual stimulus, an illusory response. This ‘McGurk’ effect is strong evidence that perceivers extract key information about a speech so...

The problem of joint source–channel and multiuser decoding for code division multiple access channels is considered. The block source–channel encoder is defined by a vector quantiser (VQ). The jointly optimum solution to such a problem has been considered before, but its extremely high complexity makes it impractical for systems with medium to large number of users and/or medium to large size o...

As the use of digital image is increasing day by day, and the amount of data required for an acceptable quality image is high, there begins a high necessity for image compression. Vector quantisation (VQ) is a novel technique for image compression. VQ is a lossy compression scheme, used to compress image both in spatial domain & frequency domain. One of the major disadvantages is high encoding ...

2 Path Integrals 3 2.1 Gaussian Integrals and Beyond... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.2 Gauge-fixing Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.2.1 Gauge-fixing: Faddeev—Popov . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.2.2 Gauge-fixing: BRST . . . . . . . . . . . . . . . . . . . . . . ...

We study the deformation (Moyal) quantisation of gravity in both the ADM and the Ashtekar approach. It is shown, that both can be treated, but lead to anomalies. The anomaly in the case of Ashtekar variables, however, is merely a central extension of the constraint algebra, which can be “lifted”. Finally we write down the equations defining physical states and comment on their physical content....

Recent developments concerning canonical quantisation and gauge invariant quantum mechanical systems and quantum field theories are briefly discussed. On the one hand, it is shown how diffeomorphic covariant representations of the Heisenberg algebra over curved manifolds of non trivial topology involve topology classes of flat U(1) bundles. On the other hand, through some examples, the recently...

A classical action is proposed which upon quantisation yields massless particles belonging to the continuous spin representation of the Poincaré group. The string generalisation of the action is identical to the tensionless extrinsic curvature action proposed by Savvidy. We show that the BRST quantisation of the string action gives a critical dimension of 28. The constraints result in a number ...