Peter Roach

Emotional speech: towards a new generation of databases

Research on speech and emotion is moving from a period of exploratory research into one where there is a prospect of substantial applications, notably in human-computer interaction. Progress in the area relies heavily on the development of appropriate databases. This paper addresses four main issues that need to be considered in developing databases of emotional speech: scope, naturalness, context and descriptors. The state of the art is reviewed. A good deal has been done to address the key issues, but there is still a long way to go. The paper shows how the challenge of developing appropriate databases is being addressed in three major recent projects--the Reading--Leeds project, the Belfast project and the CREST--ESP project. From these and other studies the paper draws together the tools and methods that have been developed, addresses the problems that arise and indicates the future directions for the development of emotional speech databases.

Structure and molecular mechanism of a nucleobase-cation- symport-1 family transporter

The nucleobase–cation–symport-1 (NCS1) transporters are essential components of salvage pathways for nucleobases and related metabolites. Here, we report the 2.85-angstrom resolution structure of the NCS1 benzyl-hydantoin transporter, Mhp1, from Microbacterium liquefaciens. Mhp1 contains 12 transmembrane helices, 10 of which are arranged in two inverted repeats of five helices. The structures of the outward-facing open and substrate-bound occluded conformations were solved, showing how the outward-facing cavity closes upon binding of substrate. Comparisons with the leucine transporter LeuTAa and the galactose transporter vSGLT reveal that the outward- and inward-facing cavities are symmetrically arranged on opposite sides of the membrane. The reciprocal opening and closing of these cavities is synchronized by the inverted repeat helices 3 and 8, providing the structural basis of the alternating access model for membrane transport.

MARSEC: A Machine-Readable Spoken English Corpus

The purpose of this paper is to describe a new version of the Spoken English Corpus which will be of interest to phoneticians and other speech scientists. The Spoken English Corpus is a well-known collection of spoken-language texts that was collected and transcribed in the 1980s in a joint project involving IBM UK and the University of Lancaster (Alderson and Knowles forthcoming, Knowles and Taylor 1988). One valuable aspect of it is that the recorded material on which it was based is fairly freely available and the recording quality is generally good. At the time when the recordings were made, the idea of storing all the recorded material in digital form suitable for computer processing was of limited practicality. Although storage on digital tape was certainly feasible, this did not provide rapid computer access. The arrival of optical disk technology, with the possibility of storing very large amounts of digital data on a compact disk at relatively low cost, has brought about a revolution in ideas on database construction and use. It seemed to us that the recordings of the Spoken English Corpus (hereafter SEC) should now be converted into a form which would enable the user to gain access to the acoustic signal without the laborious business of winding through large amounts of tape. Once this was done, we should be able not only to listen to the recordings in a very convenient way, but also to carry out many automatic analyses of the material by computer.

Prosodic cues for rated politeness in Japanese speech

Abstract In order to examine potential acoustic cues for politeness in Japanese speech, F0 and temporal aspects of polite and casual utterances of two question sentences spoken by 6 male native speakers were acoustically analysed. The analysis showed that F0 movement of the final part of utterances and speech rate of utterance were consistently differently used in these different speaking styles across all the speakers. Perceptual experiments with listeners confirmed that these acoustic variables, which were manipulated using digital resynthesis, had an impact on politeness perception. It was shown that how the final intonation of a sentence is spoken had a great impact on politeness judgements. In some cases the duration and F0 characteristics of the final vowel did change the overall impression of the utterances politeness. An experiment which used speech rate variations of a polite utterance showed the important role of this variable in perceived politeness. Politeness ratings showed an inverted U-shape as a function of speech rate, but differed according to particular speakers. The speech rate of listeners was found to affect their utterance rate preference; listeners preferred rates close to their own. These findings suggest that listener characteristics should be considered important in politeness speech research.

Transcription of prosodic and paralinguistic features of emotional speech

A study of emotional speech has resulted in a collection of some five hours of recorded material. The analysis of this material has required computer-based annotation incorporating prosodic and paralinguistic transcription as well as the coding of various psychological variables. A version of the prosodic and paralinguistic transcription devised by Crystal & Quirk was developed for use within the xwavesTM environment. This paper describes this transcription system and its application.

A Multimedia, Multilingual Teaching and Training System for Children with Speech Disorders

The development of an audiovisual pronunciation teaching and training method and software system is discussed in this article. The method is designed to help children with speech and hearing disorders gain better control over their speech production. The teaching method is drawn up for progression from individual sound preparation to practice of sounds in sentences for four languages: English, Swedish, Slovenian, and Hungarian. The system is a general language-independent measuring tool and database editor. This database editor makes it possible to construct modules for all participant languages and for different sound groups. Two modules are under development for the system in all languages: one for teaching and training vowels to hearing-impaired children and the other for correction of misarticulated fricative sounds. In the article we present the measuring methods, the used distance score calculations of the visualized speech spectra, and problems in the evaluation of the new multimedia tool.

BABEL: an Eastern European multi-language database

BABEL is a joint European project under the COPERNICUS scheme (Project 1304), comprising partners from five Eastern European countries and three Western ones. The project is producing a multi-language database of five of the most widely-differing Eastern European languages (Bulgarian, Estonian, Hungarian, Romanian and Polish). The collection and formatting of the data conforms to the protocols established by the ESPRIT SAM project and the resulting EUROM databases.

A high-throughput assay of membrane protein stability.

The preparation of purified, detergent-solubilized membrane proteins in a monodisperse and stable form is usually a prerequisite for investigation not only of their function but also for structural studies by X-ray crystallography and other approaches. Typically, it is necessary to explore a wide range of conditions, including detergent type, buffer pH, and the presence of additives such as glycerol, in order to identify those optimal for stability. Given the difficulty of expressing and purifying membrane proteins in large amounts, such explorations must ideally be performed on as small a scale as practicable. To achieve this objective in the UK Membrane Protein Structure Initiative, we have developed a rapid, economical, light-scattering assay of membrane protein aggregation that allows the testing of 48 buffer conditions in parallel on 6 protein targets, requiring less than 2 mg protein for each target. Testing of the assay on a number of unrelated membrane transporters has shown that it is of generic applicability. Proteins of sufficient purity for this plate-based assay are first rapidly prepared using simple affinity purification procedures performed in batch mode. Samples are then transferred by microdialysis into each of the conditions to be tested. Finally, attenuance at 340 nm is monitored in a 384-well plate using a plate reader. Optimal conditions for protein stability identified in the assay can then be exploited for the tailored purification of individual targets in as stable a form as possible.

Conversion between prosodic transcription systems: “Standard British” and ToBI

Abstract Althougn systems for the transcription of speech prosody have existed for a long time, the need to represent prosodic information in large-scale speech databases places new demands on such systems. The ToBI system recently developed in the USA differs in many interesting ways from conventional systems such as the “Standard British” system that has been in use for several decades. This paper discusses the differences in the context of current research on a machine-readable corpus of spoken English, and examines the possibility of converting automatically between the two types of transcription.

Reliable scale-up of membrane protein over-expression by bacterial auto-induction: From microwell plates to pilot scale fermentations

The production of well-ordered crystals of membrane proteins for structural investigation by X-ray diffraction typically requires extensive crystallization trials and may involve the screening of multiple detergents, lipids and other additives. Purification of sufficient amounts of protein for such trials is hampered by the fact that even when over-expressed, membrane proteins represent only a small percentage of the total protein content of bacteria. Fermentation-scale cultures of cells are therefore usually required. To maximize the efficiency and reduce the cost of such cultures, in the UK Membrane Protein Structure Initiative we have systematically investigated the use of auto-induction as an alternative to induction of expression with isopropyl-β-D-thiogalactoside. We report here the benefits of first optimizing expression on a multiwell plate scale by systematically varying the concentrations of glucose, glycerol, lactose and succinate present in the auto-induction medium. For subsequent scale-up, comparison of isopropyl-β-D-thiogalactoside induction in shake-flasks with auto-induction in shake-flasks and in 1L fermenters without and with control of pH and aeration revealed that highest yields of target protein were obtained using the latter culture conditions. However, analysis of the time-course of expression highlighted the importance of choosing the correct time for harvest. The high yields of target protein that can be obtained in a single batch by auto-induction, performed on a 30 l scale in a fermenter, obviate batch-to-batch variations that can add an unwanted variable to crystallization screening experiments. The approach described should therefore be of great utility for membrane protein production for structural studies.