Range entropy: A bridge between signal complexity and self-similarity

Approximate entropy (ApEn) and sample entropy (SampEn) are widely used for temporal complexity analysis of real-world phenomena. However, their relationship with the Hurst exponent as a measure of self-similarity is not widely studied. Additionally, ApEn and SampEn are susceptible to signal amplitude changes. A common practice for addressing this issue is to correct their input signal amplitude by its standard deviation. In this study, we first show, using simulations, that ApEn and SampEn are related to the Hurst exponent in their tolerance r and embedding dimension m parameters. We then propose a modification to ApEn and SampEn called range entropy or RangeEn. We show that RangeEn is more robust to nonstationary signal changes, and it has a more linear relationship with the Hurst exponent, compared to ApEn and SampEn. RangeEn is bounded in the tolerance r-plane between 0 (maximum entropy) and 1 (minimum entropy) and it has no need for signal amplitude correction. Finally, we demonstrate the clinical usefulness of signal entropy measures for characterisation of epileptic EEG data as a real-world example.Comment: This is the revised and published version in Entrop

Demonstration of sustained and useful converter responses during balanced and unbalanced faults in microgrids

In large power grids where converter penetration is presently low and the network impedance is predominantly reactive, the required response from converters during faults is presently specified by phrases such as “maximum reactive output”. However, in marine and aero power systems most faults are unbalanced, the network impedance is resistive, and converter penetration may be high. Therefore a balanced reactive fault current response to an unbalanced fault may lead to over-voltages or over/under frequency events. Instead, this paper presents a method of controlling the converter as a balanced voltage source behind a reactance, thereby emulating the fault response of a synchronous generator (SG) as closely as possible. In this mode there is a risk of converter destruction due to overcurrent. A new way of preventing destruction but still providing fault performance as close to a SG as possible is presented. Demonstrations are presented of simulations and laboratory testing at the 10kVA 400V scale, with balanced and unbalanced faults. Currents can be limited to about 1.5pu while still providing appropriate unbalanced fault response within a resistive network

A developmental and genetic classification for malformations of cortical development: update 2012.

Malformations of cerebral cortical development include a wide range of developmental disorders that are common causes of neurodevelopmental delay and epilepsy. In addition, study of these disorders contributes greatly to the understanding of normal brain development and its perturbations. The rapid recent evolution of molecular biology, genetics and imaging has resulted in an explosive increase in our knowledge of cerebral cortex development and in the number and types of malformations of cortical development that have been reported. These advances continue to modify our perception of these malformations. This review addresses recent changes in our perception of these disorders and proposes a modified classification based upon updates in our knowledge of cerebral cortical development

The study and ringing of Palaearctic birds at Ngulia Lodge, Tsavo West National Park, Kenya, 1969–2012: An overview and update

No Abstract. 

Palaearctic migrants ringed at Ngulia Lodge during autumn (October – January1), 1969–2012

No Abstract

Investigation of potential diseases associated with NorthernTerritory mammal declines - Final report<br />

Executive summaryThere is compelling evidence of broad-scale declines in populations of small terrestrial native mammals in northern Australia, including the Top End of the Northern Territory (NT) over the past 20 years. Causes under consideration include changed fire regimes, introduced fauna (including predators) and disease. To date information on health and disease in northern Australian mammals has been limited.Disease is increasingly recognised as a primary driver of some wildlife population declines and extinctions e.g., Tasmanian devil facial tumour disease, white nose syndrome in bats and chytrid fungus in amphibians.Disease has been identified as a risk factor for extinction in declining and fragmented wildlife populations globally, particularly in situations of increased environmental stressors, changing ecosystems, arrival of new vertebrate threats or climate change. Unless wild populations are studied in detail over long periods of time, the effects of disease are easily overlooked and may be difficult to determine.This study is the largest and most comprehensive study of health and disease in small mammals in northern Australia and is one of a small number of studies worldwide to have approached investigation of wildlife populations in this comprehensive manner.A total of 281 individuals from four target species were examined and sampled under anaesthesia across five main sites in the Top End of the NT, from June 2013 to Nov 2014. Non-invasive samples (ticks and faeces) were collected from a further 113 animals.Nine prioritised pathogen groups were investigated by diagnostic testing:&bull; encephalomyocarditis virus (EMCV)&bull; mammalian herpesvirus&bull; Coxiella burnetii (disease agent causing Q fever)&bull; Leptospira spp.&bull; enteric Salmonella spp.&bull; enteric protozoa (Cryptosporidium spp. and Giardia spp.)&bull; protozoal haemoparasites (trypanosomes, Babesia spp. and Hepatozoon spp.)&bull; Toxoplasma gondii&bull; gastrointestinal helminths (worms)Additional investigation was undertaken under collaborative agreements for pathogens of significance to human health: Ross River virus and Barmah Forest virus.Results were analysed for associations with locations, species, seasons, body condition, sex, blood parameters and other potential health indicators such as level of ectoparasite burden.The majority of individuals examined were assessed to be in good health and body condition.The presence of several pathogens which are known to be associated with disease in wildlife populations was identified, including mammalian herpesvirus, enteric Salmonella spp., protozoal haemoparasites (trypanosomes, Babesia spp., Hepatozoon spp.), enteric protozoa (Cryptosporidium spp. and Giardia spp.), microfilaria and Toxoplasma. Of these, several were previously unreported in target species in the NT.De novo molecular pathogen discovery studies on the northern brown bandicoot (Isoodon macrourus) used cutting-edge metagenomic techniques to look for unrecognised pathogens. Analysis is still underway; however there is evidence of several potentially significant pathogens including viruses from the Retroviridae family.A number of ectoparasite taxa that may act as vectors for infectious disease were identified.The study found evidence that several pathogens, capable of impacting population health, are circulating in Top End small mammal populations, but did not find compelling evidence that a single pathogen is responsible for, or a risk factor in, the decline of small mammals in the Top End of the NT.The study found no serological evidence of infection with encephalomyocarditis virus, Leptospira spp. or Coxiella burnetii; however it is possible that these pathogens are present in populations (at levels below detection limits due to sample sizes), with resultant morbidity or mortality.Limitations of this study include a short temporal span, a lack of longitudinal and survivorship studies, difficulties in collecting specimens from small species and an inability to study populations in the absence of feral cats and other predators. In combination these factors limit the ability to investigate the potentially complex interactions between disease and other pressures on mammal populations.Top End mammal populations are assessed to be at risk of increased levels of environmental and host stresses and are vulnerable to the likely future impacts of infectious disease. The current situation in the Top End fulfils many of the criteria necessary for an emerging infectious disease and novel disease agents should be considered as risk factors for populations. It is recommended that disease investigation continues in mammal populations of concern in the Top End in the medium to long term (five to 20 years) to increase knowledge; improve data sets; maintain and build capacity; and maximise opportunities for detection and response to new disease threats.It is recommended that future studies include, as priorities:&bull; longitudinal and survivorship studies to determine the impact of nominated pathogens on host&nbsp; survival and fitness (e.g., using cortisol and anti-oxidant capacity), and detect pathogen trends in&nbsp; individuals (e.g. whether certain pathogens are shed intermittently and whether infections persist or&nbsp; resolve).&bull; a particular focus on Toxoplasma gondii (due to its strong epidemiological link to presence of cats&nbsp; in the environment and as the only identified pathogen likely to impact a broad taxonomic range&nbsp; of mammals) and any potentially significant pathogens emerging from de novo molecular work.&nbsp; This should include a focus on sites where feral cats have been excluded, to investigate potential&nbsp; interactions between pathogen presence and predation as well as differences in prevalence of T.&nbsp; gondii in areas where the definitive host (the cat) is present/absent&bull; extension of serological studies to a wider host species range (including macropods) to determine&nbsp; the presence and prevalence of priority pathogens such as T. gondii in the landscape.Ongoing collaborative efforts between NT Department of Land Resource Management and the Conservation Medicine Program (School of Veterinary and Life Sciences), Murdoch University may facilitate research and enable continued opportunities for work funded through competitive grants or industry sponsorship

Body size as a driver of scavenging in theropod dinosaurs

This work was funded by the Earth and Natural Sciences Doctoral Studies Programme and the Higher Education Authority through the Programme for Research at Third Level Institutions, Cycle 5 (PRTLI‐5), and cofunded by the European Regional Development Fund (K.H.) and Trinity College Dublin and the Irish Research Council (A.K.).Theropod dinosaurs dominated Earth’s terrestrial ecosystem as a diverse group of predators for more than 160 million years, yet little is known about their foraging ecology. Maintaining a balanced energy budget presented a major challenge for therapods, which ranged from the chicken-sized Microraptor up to the whale-sized Giganotosaurus, in the face of intense competition and the demands of ontogenetic growth. Facultative scavenging, a behavior present in almost all modern predators, may have been important in supplementing energetically expensive lifestyles. By using agentbased models based on the allometric relationship between size and foraging behaviors, we show that theropods between 27 and 1,044 kg would have gained a significant energetic advantage over individuals at both the small and large extremes of theropod body mass through their scavenging efficiency. These results were robust to rate of competition, primary productivity, and detection distance. Our models demonstrate the potential importance of facultative scavenging in theropods and the role of body size in defining its prevalence in Mesozoic terrestrial systems.Publisher PDFPeer reviewe

Skilling Up: Providing Educational Opportunities for Aboriginal Education Workers through Technology-based Pedagogy

Over the past decade Aboriginal and Torres Strait Islander studies and perspectives have been mandated across the Australian national curriculum and all teachers are now required to demonstrate strategies for teaching Aboriginal and Torres Strait Islander students and have a broad knowledge of Aboriginal histories, cultures and languages. This paper describes a project focused on enabling Aboriginal Education Workers (AEWs) to play a critical role in transforming these initiatives into real and sustainable change through authentic, technology-based pedagogy. Indigenous research methodologies and design-based research (DBR) were used to investigate the potential educational roles for AEWs enabled by e-learning and new technologies. The project, called Skilling Up: Improving educational opportunities for AEWs through technology based pedagogy was funded by the Office of Learning and Teaching. This paper reports on the findings of the study conducted in Western Australia, including pre-study survey results, together with a description of a unit of study to provide opportunities for AEWs to use technologies in their work, and to create authentic digital stories for use in teacher education. The development of design principles for the design of such environments is also discussed

Skilling Up: Providing Educational Opportunities for Aboriginal Education Workers through Technology-based Pedagogy

Over the past decade Aboriginal and Torres Strait Islander studies and perspectives have been mandated across the Australian national curriculum and all teachers are now required to demonstrate strategies for teaching Aboriginal and Torres Strait Islander students and have a broad knowledge of Aboriginal histories, cultures and languages. This paper describes a project focused on enabling Aboriginal Education Workers (AEWs) to play a critical role in transforming these initiatives into real and sustainable change through authentic, technology-based pedagogy. Indigenous research methodologies and design-based research (DBR) were used to investigate the potential educational roles for AEWs enabled by e-learning and new technologies. The project, called Skilling Up: Improving educational opportunities for AEWs through technology based pedagogy was funded by the Office of Learning and Teaching. This paper reports on the findings of the study conducted in Western Australia, including pre-study survey results, together with a description of a unit of study to provide opportunities for AEWs to use technologies in their work, and to create authentic digital stories for use in teacher education. The development of design principles for the design of such environments is also discussed

Error analysis and calibration for a novel pipe profiling tool

Integrity of industrial pipework is ensured through routine inspection. Internal visual inspection tools are capable of characterising degradation in the form of corrosion, pitting, erosion and cracking. The accuracy of such inspection systems has a direct impact on decisions regarding the remaining lifetime of the asset. By minimising error margins, the asset may be operated with confidence for longer, with less uncertainty. This paper considers a probe system consisting of a laser profiler and camera that produces a textured 3D model of the internals of 2 – 6 inch pipework. The accuracy of the system is defined by the ability to extract laser projections from an image as it travels down the pipe, to accurately reconstruct these projections into 3D and to estimate the probe trajectory as it travels through the pipe. This paper presents an error model of the laser profiler. It then presents a novel calibration routine to reduce the error caused by misalignment and tolerances during fabrication of the system. A key advantage of the proposed calibration technique over alternatives is that we can calibrate for errors without manually adjusting the probe, which enables fabrication of a smaller more robust measurement system. In lab-based trials our calibration technique reduced peak sizing errors from 2.7mm to 0.14mm in 120mm diameter pipes