Distribution and Density of Vegetative Hydrilla Propagules in the Sediments of Two New Zealand Lakes

The distribution and density of hydrilla (Hydrilla verticillata (L.f.)Royle) turions and tubers in two New Zealand lakes were assessed by sampling cores of sediment from Lakes Tutira and Waikapiro each year from 1994 to 1997. Turion and tuber density differed with water depth, with maximum numbers of tubers and turions found in the 1-2 m and 1.5-4m water depth ranges respectively. A high turion to tuber ratio was observed, with turions accounting for over 80% of propagules. The relatively low numbers of turions and tubers compared with other reports, and the distribution of most tubers within the shallow water is likely to be associated with black swan grazing (Cygnus atratus Latham), with maintains a canopy of hydrilla consistently 1 m below the water surface

Modelling for optimisation of self-powered wireless sensor nodes

Accepted versio

Off shell κ\kappa-symmetry of the superparticle and the spinning superparticle

The spinorial local world-line $\kappa$-symmetry of the covariant Brink-Schwarz formulation of the 4-$D$ superparticle is abelian in an off-shell phase-space formulation. The result is shown to generalize to the extended spinorial transformations of the spinning superparticle.Comment: 9 pages, no fig

MEMS inertial power generators for biomedical applications

Published versio

Analysis of optimised micro-generator architectures for self-powered ubiquitous computers

Accepted versio

Automatic recognition of children’s read speech for stuttering application

Stuttering is a common speech disfluency that may persist into adulthood if not treated in its early stages. Techniques from spoken language understanding may be applied to provide auto-mated diagnoses of stuttering from voice recordings; however,there are several difficulties, including the lack of training data involving young children and the high dimensionality of these data. This study investigates how automatic speech recognition(ASR) could help clinicians by providing a tool that automatically recognises stuttering events and provides a useful written transcription of what was said. In addition, to enhance the performance of ASR and to alleviate the lack of stuttering data, this study examines the effect of augmenting the language model with artificially generated data. The performance of the ASR tool with and without language model augmentation is com-pared. Following language model augmentation, the ASR tool’s performance improved recall from 38% to 62.2% and precision from 56.58% to 71%. When mis-recognised events are more coarsely classified as stuttering/ non-stuttering events, the performance improves up to 73% in recall and 84% in precision.Although the obtained results are not perfect, they map to fairly robust stutter/ non-stutter decision boundaries

The Fate of Oil in the Water Column Following Experimental Oil Spills in the Arctic Marine Nearshore

Petroleum hydrocarbon concentrations in the water column were monitored after a release of crude oil onto the water surface and a subsurface release of chemically dispersed oil. During the surface release, petroleum hydrocarbons did not disperse into the water column deeper than 1 m. The highest concentrations observed under the slick were less than 2 mg/l. The chemically dispersed oil released resulted in concentrations over 50 mg/l in the Bay 9 study area for 12 hours. Estimated exposures of the benthic communities to oil in the three experimental bays were 3 mg/l/h, 30 mg/l/h, and 300 mg/l/h respectively. The highest exposures were to oil retaining many of its more toxic components.Key words: dispersant, oil, fluorometry, gas chromatography, oil spillMots clés: agent de dispersion, fluorométrie, chromatographie en phase gazeuse, déversement de pétrol

Analysis and optimisation of MEMS electrostatic on-chip power supply for self-powering of slow-moving sensors

Accepted versio

Optimization of inertial micropower generators for human walking motion

Published versio