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

Spelling correction in the NLP system 'LOLITA: dictionary organisation and search algorithms

This thesis describes the design and implementation of a spelling correction system and associated dictionaries, for the Natural Language Processing System 'LOLITA'. The dictionary storage is based upon a trie (M-ary tree) data-structure. The design of the dictionary is described, and the way in which the data-structure is implemented is also discussed. The spelling correction system makes use of the trie structure in order to limit repetition and "garden path' searching. The spelling correction algorithms used are a variation on the 'reverse minimum edit-distance' technique. These algorithms have been modified in order to place more emphasis on generation in order of likelihood. The system will correct up to two simple errors {i.e. insertion, omission, substitution or transposition of characters) per word. The individual algorithms are presented in turn and their combination into a unified strategy to correct misspellings is demonstrated. The system was implemented in the programming language Haskell; a pure functional, class-based language, with non-strict semantics and polymorphic type-checking. The use of several features of this language, in particular lazy evaluation, and their corresponding advantages over more traditional languages are described. The dictionaries and spelling correcting facilities are in use in the LOLITA system. Issues pertaining to 'real word' error correction, arising from the system's use in an NLP context, axe also discussed

Evaluating performance for procurement: A structured method for assessing the usability of future speech interfaces

Procurement is a process by which organizations acquire equipment to enhance the effectiveness of their operations. Equipment will only enhance effectiveness if it is usable for its purpose in the work environment, i.e. if it enables tasks to be performed to the desired quality with acceptable costs to those who operate it. Procurement presents a requirement, then, for evaluations of the performance of human-machine work systems. This thesis is concerned with the provision of information to support procurers in performing such evaluations. The Ministry of Defence (an equipment procurer) has presented a particular requirement for a means of assessing the usability of speech interfaces in the establishment of the feasibility of computerized battlefield work systems. A structured method was developed to meet this requirement, the scope, notation and process of which sought to be explicit and proceduralized. The scope was specified in terms of a conceptualization of human-computer interaction: the method supported the development of representations of the task, device and user, which could be implemented as simulations and used in empirical evaluations of system performance. Notations for representations were proposed, and procedures enabling the use of the notations. The specification and implementation of the four sub-methods is described, and subsequent enhancement in the context of evaluations of speech interfaces for battlefield observation tasks. The complete method is presented. An evaluation of the method was finally performed with respect to the quality of the assessment output and costs to the assessor. The results suggested that the method facilitated systematic assessment, although some inadequacies were identified in the expression of diagnostic information which was recruited by the procedures, and in some of the procedures themselves. The research offers support for the use of structured human factors evaluation methods in procurement. Qualifications relate to the appropriate expression of knowledge of device-user interaction, and to the conflict between requirements for flexibility and low-level proceduralization

An investigation and evaluation into the 'usibility' of human-computer interfaces using a typical CAD system

This research program covers three topics relating to the humancomputer interface namely, voice recognition, tools and techniques for evaluation, and user and interface modelling. An investigation into the implementation of voice recognition technologies examines how voice recognisers may be evaluated in commercial software. A prototype system was developed with the collaboration of FEMVIEW Ltd. (marketing a CAD package). Proposals for future research using the prototype system suggests the need for field trials to assess its usefulness in a working environment and to gain insights to end-user attitudes. A new generation of voice system is proposed based around a phoneme-based pattern matching paradigm, natural language understanding facilities and intelligent knowledgebased systems capable of building on knowledge by inference and deduction. In order to assess the 'usability' of the FEMVIEW CAD software a subject-base' formal evaluation w-s cond""ct-d which involved: - (1) the analysis of responses to a multi-user survey of end-user attitudes; (2) collecting behavioural performance measures from students learning to use the software. (3) cognitive and affective data obtained from laboratory experimentation using experienced users of the CAD package. A theoretical approach to evaluation leads to the hypothesis that human-computer interaction is affected by personality, influencing types of dialogue, preferred methods for providing help, etc. A user model based on personality traits, or habitual behaviour patterns (HBP) is presented. Proposals are given to use the HBP model in future self-adaptive interfaces. Results from experimentation to justify the model are inconclusive. Finally, a practical framework is provided for the evaluation of human-computer interfaces. It suggests that evaluation is an integral part of design and that the iterative use of evaluation techniques throughout the conceptualisation, design, implementation and postimplementation stages will ensure systems that satisfy the needs of the users and fulfil the goal of 'usability'. The major contributions made to the knowledge of this subject can be summarised as follows: (1) the practical problems of implementing voice recognition technologies in commercial software; (2) the development of a new personalised user model which accounts for individual's idiosyncrasies; (3) methods for applying simple evaluation techniques in order to assess software 'usability'; (4) a practical framework for developing usable software

Development of an eclectic dictionary for court reporting

The purpose of this research was to evaluate the resources available to the field of court reporting in the United States, specifically, the existence of an eclectic dictionary which encompasses all known methodologies and advanced principles; This study reviewed articles, texts, and manuals pertaining to court reporting to ascertain the need for an eclectic dictionary; A questionnaire was prepared and sent to all court reporting program directors of accredited programs in the United States. They were asked to provide their overall philosophy in terms of developing an eclectic dictionary and requested to respond about the need for such a dictionary; From the responses to the survey, an eclectic dictionary was created and included and appended to the study

Custodians of continuity in an era of change: an oral history of the everyday lives of Crown Court clerks between 1972 and 2015

This thesis investigates the life histories of Crown Court clerks between 1972 and 2015, and has uncovered unheard testimonies of the lived world of law. Drawing on 21 oral history interviews, it is posited that the Crown Court clerk was a pivotal player in the legal system during this period and their contribution to the performance of law has been largely neglected. Though they did not enjoy the economic, social and cultural capital of judges and barristers, or play a central role in the construction and determination of legal issues in hearings, they were chiefly responsible for the smooth functioning of the courtroom, and were constantly working to maintain order and facilitate the flow of proceedings. Court clerks can be characterised as stage managers of the courtroom drama in the sense that the onus was upon them to ensure that all the various props and parties were assembled in the courtroom at the right time, and to direct defendants, witnesses and jurors as to where and when to sit, stand, and what to say at the appropriate moment. Moreover, this thesis asserts that alongside judges and barristers, court clerks were active agents in the perpetuation of traditional practices through their use of official and formal codes of dress, speech and behaviour, and can be perceived as custodians of continuity. This finding is particularly interesting in light of scholarly accounts that have identified a period of radical change to the administration of justice following the founding of the new Courts Service in 1972. It is contended that Crown court clerks were not merely complicit in, but strongly supported a highly ritualised performance of justice. In so doing, they contributed towards upholding the authority and legitimacy of the criminal justice system in ways that have been largely unacknowledged