89,305 research outputs found
Bayesian Speaker Adaptation Based on a New Hierarchical Probabilistic Model
In this paper, a new hierarchical Bayesian speaker adaptation method called HMAP is proposed that combines the advantages of three conventional algorithms, maximum a posteriori (MAP), maximum-likelihood linear regression (MLLR), and eigenvoice, resulting in excellent performance across a wide range of adaptation conditions. The new method efficiently utilizes intra-speaker and inter-speaker correlation information through modeling phone and speaker subspaces in a consistent hierarchical Bayesian way. The phone variations for a specific speaker are assumed to be located in a low-dimensional subspace. The phone coordinate, which is shared among different speakers, implicitly contains the intra-speaker correlation information. For a specific speaker, the phone variation, represented by speaker-dependent eigenphones, are concatenated into a supervector. The eigenphone supervector space is also a low dimensional speaker subspace, which contains inter-speaker correlation information. Using principal component analysis (PCA), a new hierarchical probabilistic model for the generation of the speech observations is obtained. Speaker adaptation based on the new hierarchical model is derived using the maximum a posteriori criterion in a top-down manner. Both batch adaptation and online adaptation schemes are proposed. With tuned parameters, the new method can handle varying amounts of adaptation data automatically and efficiently. Experimental results on a Mandarin Chinese continuous speech recognition task show good performance under all testing conditions
Good reductions of Shimura varieties of Hodge type in arbitrary unramified mixed characteristic. Part I
We prove the existence of good smooth integral models of Shimura varieties of
Hodge type in arbitrary unramified mixed characteristic . As a first
application we provide a smooth solution (answer) to a conjecture (question) of
Langlands for Shimura varieties of Hodge type. As a second application we prove
the existence in arbitrary unramified mixed characteristic of integral
canonical models of projective Shimura varieties of Hodge type with respect to
h--hyperspecial subgroups as pro-\'etale covers of N\'eron models; this forms
progress towards the proof of conjectures of Milne and Reimann. Though the
second application was known before in some cases, its proof is new and more of
a principle.Comment: 87 pages. Final version, to appear in Mathematische Nachrichten (most
alignment issues kept loose to match with the layout of the journal
Integral canonical models of unitary Shimura varieties
We prove the existence of integral canonical models of unitary Shimura
varieties in arbitrary unramified mixed characteristic. Errata to [Va1] are
also included.Comment: 27 pages. Accepted (in final form) for publication in Asian J. Mat
Paper folding, Riemann surfaces, and convergence of pseudo-Anosov sequences
A method is presented for constructing closed surfaces out of Euclidean
polygons with infinitely many segment identifications along the boundary. The
metric on the quotient is identified. A sufficient condition is presented which
guarantees that the Euclidean structure on the polygons induces a unique
conformal structure on the quotient surface, making it into a closed Riemann
surface. In this case, a modulus of continuity for uniformizing coordinates is
found which depends only on the geometry of the polygons and on the
identifications. An application is presented in which a uniform modulus of
continuity is obtained for a family of pseudo-Anosov homeomorphisms, making it
possible to prove that they converge to a Teichm\"uller mapping on the Riemann
sphere.Comment: 75 pages, 18 figure
Crystal melting on toric surfaces
We study the relationship between the statistical mechanics of crystal
melting and instanton counting in N=4 supersymmetric U(1) gauge theory on toric
surfaces. We argue that, in contrast to their six-dimensional cousins, the two
problems are related but not identical. We develop a vertex formalism for the
crystal partition function, which calculates a generating function for the
dimension 0 and 1 subschemes of the toric surface, and describe the
modifications required to obtain the corresponding gauge theory partition
function.Comment: 30 pages; v2: references adde
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