Yoshinao Shiraki

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As was observed by Castro and Galligo [3] , [5], the Buchberger algorithm for computing Gröbner bases of ideals of the polynomial ring applies also to the Weyl algebra, i.e., the ring of differential operators with polynomial coefficients. This generalization of the Buchberger algorithm has turned out to be very fruitful in the computational approach to the(More)
This paper proposes to use zooming function of digital cameras for robust character recognition and to control focal length for improving the performance even in dim light conditions. For this purpose, we determine the optimum focal length vs. camera-object distance through several recognition experiments. Recognition performance for insufficient(More)
We propose a new class of binary nonlinear codes of constant weights derived from a permutation representation of a group that is given by a combinatorial definition such as Cayley graphs of a group. These codes are constructed by the following direct interpretation method from a group: (1) take one discrete group whose elements are defined by generators(More)
The paper presents a new weighting function that can be used in the method of iteratively reweighted least squares (IRWLS) for designing equiripple all-pass IIR filters. The purpose of introducing this weighting function is to improve the convergence performance in the solution of the IRWLS. The height of each weighting function is designed to be equal to(More)
This paper aims a t t h e speaker-independen t very-low b i t ra te speed coding and proposes t h e speaker adap ta t ion algori thm based on t h e piecewise movement i n t h e speech spectrum space. In t h e proposed method, t h e un ive r sa l codebook, which i s cons t ruc t ed beforehand based on t h e f e a t u r e s of t h e spect r a l d i s t r i b(More)
We study the relation between a spectral deformation in speech processing and a geometrical deformation theory. We show that topological field theory yields the systematic treatment of these two methods. Some of the examples and the application to speech-spectra of classical mathematical ideas — for example, Morse theory in higher dimensions —(More)
Let A(n, d, w) denote the maximum possible number of code words in binary (n, d, w) constant weight codes. For smaller instances of (n, d, w)s, many improvements have occurred over the decades. However, unknown instances still remain for larger (n, d, w)s (for example, those of n > 30 and d > 10). In this paper, we propose a new class of binary constant(More)