Towards an automatic speech recognition system for use by deaf students in lectures

According to the Royal National Institute for Deaf people there are nearly 7.5 million hearing-impaired people in Great Britain. Human-operated machine transcription systems, such as Palantype, achieve low word error rates in real-time. The disadvantage is that they are very expensive to use because of the difficulty in training operators, making them impractical for everyday use in higher education. Existing automatic speech recognition systems also achieve low word error rates, the disadvantages being that they work for read speech in a restricted domain. Moving a system to a new domain requires a large amount of relevant data, for training acoustic and language models. The adopted solution makes use of an existing continuous speech phoneme recognition system as a front-end to a word recognition sub-system. The subsystem generates a lattice of word hypotheses using dynamic programming with robust parameter estimation obtained using evolutionary programming. Sentence hypotheses are obtained by parsing the word lattice using a beam search and contributing knowledge consisting of anti-grammar rules, that check the syntactic incorrectness’ of word sequences, and word frequency information. On an unseen spontaneous lecture taken from the Lund Corpus and using a dictionary containing "2637 words, the system achieved 815% words correct with 15% simulated phoneme error, and 73.1% words correct with 25% simulated phoneme error. The system was also evaluated on 113 Wall Street Journal sentences. The achievements of the work are a domain independent method, using the anti- grammar, to reduce the word lattice search space whilst allowing normal spontaneous English to be spoken; a system designed to allow integration with new sources of knowledge, such as semantics or prosody, providing a test-bench for determining the impact of different knowledge upon word lattice parsing without the need for the underlying speech recognition hardware; the robustness of the word lattice generation using parameters that withstand changes in vocabulary and domain

Aviation Safety/Automation Program Conference

The Aviation Safety/Automation Program Conference - 1989 was sponsored by the NASA Langley Research Center on 11 to 12 October 1989. The conference, held at the Sheraton Beach Inn and Conference Center, Virginia Beach, Virginia, was chaired by Samuel A. Morello. The primary objective of the conference was to ensure effective communication and technology transfer by providing a forum for technical interchange of current operational problems and program results to date. The Aviation Safety/Automation Program has as its primary goal to improve the safety of the national airspace system through the development and integration of human-centered automation technologies for aircraft crews and air traffic controllers

The Challenge of Spoken Language Systems: Research Directions for the Nineties

A spoken language system combines speech recognition, natural language processing and human interface technology. It functions by recognizing the person's words, interpreting the sequence of words to obtain a meaning in terms of the application, and providing an appropriate response back to the user. Potential applications of spoken language systems range from simple tasks, such as retrieving information from an existing database (traffic reports, airline schedules), to interactive problem solving tasks involving complex planning and reasoning (travel planning, traffic routing), to support for multilingual interactions. We examine eight key areas in which basic research is needed to produce spoken language systems: (1) robust speech recognition; (2) automatic training and adaptation; (3) spontaneous speech; (4) dialogue models; (5) natural language response generation; (6) speech synthesis and speech generation; (7) multilingual systems; and (8) interactive multimodal systems. In each area, we identify key research challenges, the infrastructure needed to support research, and the expected benefits. We conclude by reviewing the need for multidisciplinary research, for development of shared corpora and related resources, for computational support and far rapid communication among researchers. The successful development of this technology will increase accessibility of computers to a wide range of users, will facilitate multinational communication and trade, and will create new research specialties and jobs in this rapidly expanding area

The Challenge of Spoken Language Systems: Research Directions for the Nineties

A spoken language system combines speech recognition, natural language processing and human interface technology. It functions by recognizing the person's words, interpreting the sequence of words to obtain a meaning in terms of the application, and providing an appropriate response back to the user. Potential applications of spoken language systems range from simple tasks, such as retrieving information from an existing database (traffic reports, airline schedules), to interactive problem solving tasks involving complex planning and reasoning (travel planning, traffic routing), to support for multilingual interactions. We examine eight key areas in which basic research is needed to produce spoken language systems: (1) robust speech recognition; (2) automatic training and adaptation; (3) spontaneous speech; (4) dialogue models; (5) natural language response generation; (6) speech synthesis and speech generation; (7) multilingual systems; and (8) interactive multimodal systems. In each area, we identify key research challenges, the infrastructure needed to support research, and the expected benefits. We conclude by reviewing the need for multidisciplinary research, for development of shared corpora and related resources, for computational support and far rapid communication among researchers. The successful development of this technology will increase accessibility of computers to a wide range of users, will facilitate multinational communication and trade, and will create new research specialties and jobs in this rapidly expanding area

A statistical approach to language modelling for the ATIS problem

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (p. 62-65).by Joshua D. Koppelman.M.Eng

Identification of Causal Paths and Prediction of Runway Incursion Risk using Bayesian Belief Networks

In the U.S. and worldwide, runway incursions are widely acknowledged as a critical concern for aviation safety. However, despite widespread attempts to reduce the frequency of runway incursions, the rate at which these events occur in the U.S. has steadily risen over the past several years. Attempts to analyze runway incursion causation have been made, but these methods are often limited to investigations of discrete events and do not address the dynamic interactions that lead to breaches of runway safety. While the generally static nature of runway incursion research is understandable given that data are often sparsely available, the unmitigated rate at which runway incursions take place indicates a need for more comprehensive risk models that extend currently available research. This dissertation summarizes the existing literature, emphasizing the need for cross-domain methods of causation analysis applied to runway incursions in the U.S. and reviewing probabilistic methodologies for reasoning under uncertainty. A holistic modeling technique using Bayesian Belief Networks as a means of interpreting causation even in the presence of sparse data is outlined in three phases: causal factor identification, model development, and expert elicitation, with intended application at the systems or regulatory agency level. Further, the importance of investigating runway incursions probabilistically and incorporating information from human factors, technological, and organizational perspectives is supported. A method for structuring a Bayesian network using quantitative and qualitative event analysis in conjunction with structured expert probability estimation is outlined and results are presented for propagation of evidence through the model as well as for causal analysis. In this research, advances in the aggregation of runway incursion data are outlined, and a means of combining quantitative and qualitative information is developed. Building upon these data, a method for developing and validating a Bayesian network while maintaining operational transferability is also presented. Further, the body of knowledge is extended with respect to structured expert judgment, as operationalization is combined with elicitation of expert data to create a technique for gathering expert assessments of probability in a computationally compact manner while preserving mathematical accuracy in rank correlation and dependence structure. The model developed in this study is shown to produce accurate results within the U.S. aviation system, and to provide a dynamic, inferential platform for future evaluation of runway incursion causation. These results in part confirm what is known about runway incursion causation, but more importantly they shed more light on multifaceted causal interactions and do so in a modeling space that allows for causal inference and evaluation of changes to the system in a dynamic setting. Suggestions for future research are also discussed, most prominent of which is that this model allows for robust and flexible assessment of mitigation strategies within a holistic model of runway safety

A characterization of the problem of new, out-of-vocabulary words in continuous-speech recognition and understanding

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (p. 167-173).by Irvine Lee Hetherington.Ph.D

Semi-automatic acquisition of domain-specific semantic structures.

Siu, Kai-Chung.Thesis (M.Phil.)--Chinese University of Hong Kong, 2000.Includes bibliographical references (leaves 99-106).Abstracts in English and Chinese.Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Thesis Outline --- p.5Chapter 2 --- Background --- p.6Chapter 2.1 --- Natural Language Understanding --- p.6Chapter 2.1.1 --- Rule-based Approaches --- p.7Chapter 2.1.2 --- Stochastic Approaches --- p.8Chapter 2.1.3 --- Phrase-Spotting Approaches --- p.9Chapter 2.2 --- Grammar Induction --- p.10Chapter 2.2.1 --- Semantic Classification Trees --- p.11Chapter 2.2.2 --- Simulated Annealing --- p.12Chapter 2.2.3 --- Bayesian Grammar Induction --- p.12Chapter 2.2.4 --- Statistical Grammar Induction --- p.13Chapter 2.3 --- Machine Translation --- p.14Chapter 2.3.1 --- Rule-based Approach --- p.15Chapter 2.3.2 --- Statistical Approach --- p.15Chapter 2.3.3 --- Example-based Approach --- p.16Chapter 2.3.4 --- Knowledge-based Approach --- p.16Chapter 2.3.5 --- Evaluation Method --- p.19Chapter 3 --- Semi-Automatic Grammar Induction --- p.20Chapter 3.1 --- Agglomerative Clustering --- p.20Chapter 3.1.1 --- Spatial Clustering --- p.21Chapter 3.1.2 --- Temporal Clustering --- p.24Chapter 3.1.3 --- Free Parameters --- p.26Chapter 3.2 --- Post-processing --- p.27Chapter 3.3 --- Chapter Summary --- p.29Chapter 4 --- Application to the ATIS Domain --- p.30Chapter 4.1 --- The ATIS Domain --- p.30Chapter 4.2 --- Parameters Selection --- p.32Chapter 4.3 --- Unsupervised Grammar Induction --- p.35Chapter 4.4 --- Prior Knowledge Injection --- p.40Chapter 4.5 --- Evaluation --- p.43Chapter 4.5.1 --- Parse Coverage in Understanding --- p.45Chapter 4.5.2 --- Parse Errors --- p.46Chapter 4.5.3 --- Analysis --- p.47Chapter 4.6 --- Chapter Summary --- p.49Chapter 5 --- Portability to Chinese --- p.50Chapter 5.1 --- Corpus Preparation --- p.50Chapter 5.1.1 --- Tokenization --- p.51Chapter 5.2 --- Experiments --- p.52Chapter 5.2.1 --- Unsupervised Grammar Induction --- p.52Chapter 5.2.2 --- Prior Knowledge Injection --- p.56Chapter 5.3 --- Evaluation --- p.58Chapter 5.3.1 --- Parse Coverage in Understanding --- p.59Chapter 5.3.2 --- Parse Errors --- p.60Chapter 5.4 --- Grammar Comparison Across Languages --- p.60Chapter 5.5 --- Chapter Summary --- p.64Chapter 6 --- Bi-directional Machine Translation --- p.65Chapter 6.1 --- Bilingual Dictionary --- p.67Chapter 6.2 --- Concept Alignments --- p.68Chapter 6.3 --- Translation Procedures --- p.73Chapter 6.3.1 --- The Matching Process --- p.74Chapter 6.3.2 --- The Searching Process --- p.76Chapter 6.3.3 --- Heuristics to Aid Translation --- p.81Chapter 6.4 --- Evaluation --- p.82Chapter 6.4.1 --- Coverage --- p.83Chapter 6.4.2 --- Performance --- p.86Chapter 6.5 --- Chapter Summary --- p.89Chapter 7 --- Conclusions --- p.90Chapter 7.1 --- Summary --- p.90Chapter 7.2 --- Future Work --- p.92Chapter 7.2.1 --- Suggested Improvements on Grammar Induction Process --- p.92Chapter 7.2.2 --- Suggested Improvements on Bi-directional Machine Trans- lation --- p.96Chapter 7.2.3 --- Domain Portability --- p.97Chapter 7.3 --- Contributions --- p.97Bibliography --- p.99Chapter A --- Original SQL Queries --- p.107Chapter B --- Induced Grammar --- p.109Chapter C --- Seeded Categories --- p.11

Subword lexical modelling for speech recognition

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (p. 155-160).by Raymond Lau.Ph.D