PAC Learning Constraint Dependency Grammar Constraints

Constraint Dependency Grammar (CDG) [11, 13] is a constraint-based grammatical formalism that has proven effective for processing English [5] and improving the accuracy of spoken language understanding systems [4]. However, prospective users of CDG face a steep learning curve when trying to master this powerful formalism. Therefore, a recent trend in CDG research has been to try to ease the burden of grammar writers by developing methods for automatically learning CDG grammars from annotated sentences [22, 23]. In this paper, we prove that CDG grammar constraints are PAC learnable. 1 Introduction Constraint Dependency Grammar (CDG) [11, 13] is a constraint-based grammatical formalism that has proven effective for processing English [5] and improving the accuracy of spoken language understanding systems [4]. However, prospective users of CDG face a steep learning curve when trying to This material is based upon work supported by a grant from the Intel Research Council and the Nation..

A Parallel Implementation of a Hidden Markov Model with Duration Modeling for Speech Recognition

Hidden Markov models (HMMs) are currently the most successful paradigm for speech recognition. Although explicit duration continuous HMMs more accurately model speech than HMMs with implicit duration modeling, the cost of accurate duration modeling is often considered prohibitive. This paper describes a parallel implementation of an HMM with explicit duration modeling for spoken language recognition on the MasPar MP-1. The MP-1 is a fine-grained SIMD architecture with 16384 processing elements (PEs) arranged in a 128x128 mesh. By exploiting the massive parallelism of explicit duration HMMs, development and testing is practical even for large amounts of data. The result of this work is a parallel speech recognizer that can train a phone recognizer in real time. We present several extensions that include context dependent modeling, word recognition, and implicit duration HMMs. 1 Introduction While hidden Markov models (HMMs) have been a popular and effective method of recognizing spoken..