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Algorithmic methods in D modules have been used in mathematical study of hypergeometric functions and in computational algebraic geometry. In this paper, we show that these algorithms give correct algorithms to perform several operations for holonomic functions and also generates substantial information for numerical evaluation of holonomic functions.

This paper presents a new speaker adaptation method based on a piece-wise linear mapping of spectral code vector space into thespectral vector space of an unknown speaker. Adaptation is performed by modifying the code vectors to give a better fit to input the spectral vectors, while maintaining the local continuity of distribution of the original code vectors. Two adaptation algorithms are presented. One is a minimum distortion method which provides a monotonic non-increasing distortion for the training data. The other is a simplified method. These algorithms are investigated in terms of distortion performance and adaptation speed. Experimental results show that the proposed method provides much higher adaptation speed than the LBG algorithm and that the distortion performance approaches that of the LBG algorithm as the size of training data increases.

This paper presents a very low bit rate LPC vocoder based on a joint segmentation and quantization method using spectral segments having variable time length. The method exploits the nonuniform distribution of speech characteristics in the time and spectral domains. A measure of the spectral distance between a variable-length input speech segment and a fixed-length segment template is introduced based on linear time warping. The optimum segment boundaries and templates for a spectral sequence are efficiently determined using a dynamic programming technique so that the total spectral distortion in a voice interval is minimized. The segment templates are obtained by a sub-optimum pattern learning method, which guarantees a monotonic decrease in distortion, using a combined segmentation and clustering technique. Experimental results for a single male speaker show that this method reduces the initial distortion by 20% and yields a sound articulation score of 78%.

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