Estimation of Glottal Closure Instants in Voiced Speech Using the DYPSA Algorithm

We present the Dynamic Programming Projected Phase-Slope Algorithm (DYPSA) for automatic estimation of glottal closure instants (GCIs) in voiced speech. Accurate estimation of GCIs is an important tool that can be applied to a wide range of speech processing tasks including speech analysis, synthesis and coding. DYPSA is automatic and operates using the speech signal alone without the need for an EGG signal. The algorithm employs the phase-slope function and a novel phase-slope projection technique for estimating GCI candidates from the speech signal. The most likely candidates are then selected using a dynamic programming technique to minimize a cost function that we define. We review and evaluate three existing methods of GCI estimation and compare the new DYPSA algorithm to them. Results are presented for the APLAWD and SAM databases for which 95.7% and 93.1% of GCIs are correctly identified     

A 130 point Nd:YAG Thomson scattering diagnostic on MAST

A Thomson scattering diagnostic designed to measure both edge and core physics has been implemented on MAST. The system uses eight Nd:YAG lasers, each with a repetition rate of 30 Hz. The relative and absolute timing of the lasers may be set arbitrarily to produce fast bursts of measurements to suit the time evolution of the physics being studied. The scattered light is collected at F/6 by a 100 kg six element lens system with an aperture stop of 290 mm. The collected light is then transferred to 130 polychromators by 130 independent fiber bundles. The data acquisition and processing are based on a distributed computer system of dual core processors embedded in 26 chassis. Each chassis is standalone and performs data acquisition and processing for five polychromators. This system allows data to be available quickly after the MAST shot and has potential for real-time operations.     

MAST YAG Thomson scattering upgrade alignment system

The recent upgrade to the MAST YAG Thomson scattering while enhancing the diagnostic capabilities increased the complexity of the system. There are eight YAG lasers now operational, doubling the number from the previous setup. This means alignment between each laser individually and reference points is essential to guarantee data quality and diagnostic reliability. To address this issue an alignment system was recently installed. It mimics the beams alignment in MAST by sampling 1% of the laser beam that is sent into a telescope which demagnifies by a factor of 8. The demagnified beam is viewed with a CCD camera. By scanning the camera the profile and position of the beams in the scattering zone and in a range of several meters inside MAST can be determined. Therefore alignment is checked along the beam path without having to sample it inside the vessel. The experimental apparatus and test procedures are described.     

THE IRISH SEA REGION: WHY THE GENERAL LACK OF EXPLORATION SUCCESS?

With the exception of the prolific East Irish Sea Basin, there have been no hydrocarbon discoveries to date in the other basins in the Irish Sea region. Excellent reservoirs, viable seals and structural traps have been identified in all the basins, suggesting that other factors have prevented the accumulation or preservation of oil and gas. The lack of exploration success in the Larne - Lough Neagh, Solway and Peel, Kish Bank and Central Irish Sea Basins is attributed to a combination of poor preservation of regional source rocks, unfavourable timing of hydrocarbon migration and trap formation and, locally, a lack of seal integrity. Inversion episodes during latest Carboniferous, Late Jurassic-Early Cretaceous and Early Tertiary times were critical in preventing the optimum conditions necessary for the generation and preservation of oil and gas in these basins.     

A quantitative assessment of group delay methods for identifying glottal closures in voiced speech

Measures based on the group delay of the LPC residual have been used by a number of authors to identify the time instants of glottal closure in voiced speech. In this paper, we discuss the theoretical properties of three such measures and we also present a new measure having useful properties. We give a quantitative assessment of each measure's ability to detect glottal closure instants evaluated using a speech database that includes a direct measurement of glottal activity from a Laryngograph/EGG signal. We find that when using a fixed-length analysis window, the best measures can detect the instant of glottal closure in 97% of larynx cycles with a standard deviation of 0.6 ms and that in 9% of these cycles an additional excitation instant is found that normally corresponds to glottal opening. We show that some improvement in detection rate may be obtained if the analysis window length is adapted to the speech pitch. If the measures are applied to the preemphasized speech instead of to the LPC residual, we find that the timing accuracy worsens but the detection rate improves slightly. We assess the computational cost of evaluating the measures and we present new recursive algorithms that give a substantial reduction in computation in all cases.     

Microbial aspects of protein recovery from meat industry by-products

A significant reduction in the number of micro-organisms associated with the bovine meat by-products, lung, rumen and blood plasma, was noted after their alkali-extractable proteins had been spun into a fibrous form. Most of the effect was found when the protein was coagulated in a 10% acetic acid/10% sodium chloride bath. Whereas the approximate shelf-life of raw rumen and lung was three and four days, respectively (at 0°C), proteins isolated from these tissues were relatively stable and could be stored for up to three weeks. Spun protein fibres were even more resistant to microbial spoilage and were stable for at least three years. Tests for specific food poisoning organisms on the spun protein fibres revealed an absence of coliforms, Staphylococcus aureus and Salmonella/Shigella spp.