R. J. Wiltshire

University of Tasmania

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Rapid Detection of Changes to Individual Modes in Multimodal Power Systems

R. J. Wiltshire Peter O’Shea Gerard Ledwich

This paper describes a new method for rapidly detecting modal deterioration in large interconnected multimodal power systems. Any "sudden detrimental change" of an individual mode is detected using strategies derived from optimal detection theory. A statistical characterisation is used to establish reliable thresholds for detection of individual mode changes.

Mode (computer interface)

Statistical power

Detection theory

10.1109/tencon.2005.301037

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Citations (1)

Robertson-Walker Fluid Sources Endowed with Rotation Characterised by Quadratic Terms in Angular Velocity Parameter

General Relativity and Gravitation (2003)

R. J. Wiltshire P. Messenger

Perfect fluid

Constant angular velocity

10.1023/a:1024582618096

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Citations (0)

Fluid spheres and R- and T-regions in general relativity

International Journal of Theoretical Physics (1975)

G. C. McVittie R. J. Wiltshire

Perfect fluid

Black hole (networking)

10.1007/bf01807663

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Citations (21)

Contents, Vol. 71, 1995

Cytogenetic and Genome Research (1995)

Göran Stenman E. Röijer Ulla Rüetschi Anita Dellsèn Lars Rymo

10.1159/000134134

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Citations (0)

An analytical approach to coupled heat and moisture transport in soil

Transport in Porous Media (1995)

R. Shepherd R. J. Wiltshire

Harmonic

10.1007/bf01073177

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Citations (12)

Multiplexer–Demultiplexer based on nematic liquid crystal photonic crystal fiber coupler

Optical and Quantum Electronics (2009)

Mohamed Farhat O. Hameed S. S. A. Obayya R. J. Wiltshire

Demultiplexer

Beam propagation method

10.1007/s11082-009-9334-x

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Citations (48)

The use of Fourier descriptors in the classification of particle shape

Sedimentology (1995)

M�nch Thomas R. J. Wiltshire A. T. Williams

ABSTRACT A new quantitative method for characterizing quartz grain shape is presented. The method employs a harmonic analysis based upon Fourier descriptors which is a distinct variation of the traditional and widely used Fourier series. Quartz grain images from a scanning electron microscope were ‘frame grabbed’and converted to a digitized grey‐level image. The image processing techniques of enhancement, segmentation and boundary tracking were applied to remove all features except the image boundary. This boundary was sampled at uniform intervals of are length and represented mathematically on the complex plane. In this way problems associated with the location of particle centroid and re‐entrant values were avoided. The resulting data was standardized relative to scale, rotation and starting position. Hence the discrete Fourier transform was applied using modern fast Fourier transform techniques and the modulus of the resulting harmonic amplitude used to characterize the grain shape. The technique was applied to a sample of 0–5‐m quartz grains from three distinct populations: desert quartz, beach grains (Fire Island, New York) and Brazilian crushed quartz. Whilst plots of average amplitude vs. harmonic number for each population appeared similar, discriminant analysis applied to each grain sample distinguished characteristic grain shape with an excellent degree of success. The problems of location of the centroid and re‐entrant values were eliminated. This allowed the technique to be applied to a much wider group of irregularly shaped sedimentary particles such as loess.

Centroid

Discrete-time Fourier transform

Harmonic

Position (finance)

10.1111/j.1365-3091.1995.tb00397.x

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Citations (73)

Quantitative genetic evidence that the timing of vegetative phase change in Eucalyptus globulus ssp. globulus is an adaptive trait

Australian Journal of Botany (2000)

Gregory J. Jordan BM Potts Paula Chalmers R. J. Wiltshire

Quantitative genetic analysis of six field trials suggests a complex pattern of adaptive significance for the timing of the abrupt change in leaf form in Eucalyptus globulus Labill. spp. globulus. Data from one small trial demonstrated a genetic basis to a steep local cline in habit, in the size of plants flowering and in the height of the change in foliage type. Thus, slow growth, early phase change and precocious flowering appear to be maintained in exposed coastal environments by current selection. This contrasts with results from five large trials that contained open-pollinated progeny from across the whole geographic range of this taxon. On this broad scale, early phase change appears to promote growth, a fitness surrogate, in two trials but not the others, implying differential selection for the timing of phase change. In these cases, early phase change may have been favoured in warm, wet environments by reducing damage by leaf fungi. There was marked genetic variation in the timing of vegetative phase change among broad regions, consistent with either adaptation to broad-scale environmental variation or historical differentiation.

Eucalyptus globulus

Mycology

Cline (biology)

Trait

Local adaptation

Tree breeding

10.1071/bt99038

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Citations (78)

Eucalypt genetics and genecology

Cambridge University Press eBooks (1997)

BM Potts R. J. Wiltshire

Source

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Citations (121)

The origin of Eucalyptus vernicosa, a unique shrub eucalypt

Biological Journal of the Linnean Society (2001)

Marian Hazel McGowen R. J. Wiltshire BM Potts René E. Vaillancourt

The morphology of the Tasmanian yellow gum eucalypts varies clinally over less than 1.5 km on Mt Arrowsmith, from small shrubs on the mountaintops (Eucalyptus vernicosa), through small trees (E. subcrenulata) in sub-alpine woodland, to tall forest trees near the base of the mountain (classified as E. johnstonii or E. subcrenulata). This cline suggests a possible origin of E. vernicosa by primary differentiation. This study examines the origin of E. vernicosa on Mt Arrowsmith and two other Tasmanian mountains using four microsatellite loci. The analysis confirmed the continuous nature of the morphological variation on Mt Arrowsmith, whereas the variation on the other mountains was discontinuous. However, no corresponding pattern of clinal variation was found in microsatellite markers, with a large discontinuity between the E. vernicosa and E. subcrenulata. Eucalyptus vernicosa populations from widely separated mountains had greater genetic affinities to each other than to parapatric populations of E. subcrenulata. Morphologically intermediate phenotypes between E. vernicosa and E. subcrenulata were genetically indistinguishable from E. vernicosa. This pattern of genetic differentiation suggests that E. vernicosa evolved in allopatry and the cline on Mt Arrowsmith arose from two gene pools converging in morphology from opposite directions.

Parapatric speciation

Cline (biology)

Eucalyptus camaldulensis

Hybrid zone

10.1111/j.1095-8312.2001.tb01401.x

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Citations (21)