ORCID Profile
0000-0003-3865-511X
Current Organisation
University of Adelaide
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Institution of Engineering and Technology (IET)
Date: 10-2013
DOI: 10.1049/EL.2013.2547
Publisher: AIP Publishing
Date: 31-08-2001
DOI: 10.1063/1.1397769
Abstract: In this paper we use the analogy of Parrondo’s games to design a second order switched mode circuit which is unstable in either mode but is stable when switched. We do not require any sophisticated control law. The circuit is stable, even if it is switched at random. We use a stochastic form of Lyapunov’s second method to prove that the randomly switched system is stable with probability of one. Simulations show that the solution to the randomly switched system is very similar to the analytic solution for the time-averaged system. This is consistent with the standard techniques for switched state-space systems with periodic switching. We perform state-space simulations of our system, with a randomized discrete-time switching policy. We also examine the case where the control variable, the loop gain, is a continuous Gaussian random variable. This gives rise to a matrix stochastic differential equation (SDE). We know that, for a one-dimensional SDE, the difference between solution for the time averaged system and any given s le path for the SDE will be an appropriately scaled and conditioned version of Brownian motion. The simulations show that this is approximately true for the matrix SDE. We examine some numerical solutions to the matrix SDE in the time and frequency domains, for the case where the noise power is very small. We also perform some simulations, without analysis, for the same system with large amounts of noise. In this case, the solution is significantly shifted away from the solution for the time-averaged system. The Brownian motion terms dominate all other aspects of the solution. This gives rise to very erratic and “bursty” behavior. The stored energy in the system takes the form a logarithmic random walk. The simulations of our curious circuit suggest that it is possible to implement a control algorithm that actively uses noise, although too much noise eventually makes the system unusable.
Publisher: Springer Science and Business Media LLC
Date: 17-03-2020
DOI: 10.1038/S41598-020-62013-Y
Abstract: An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2015
Publisher: SPIE
Date: 25-05-2004
DOI: 10.1117/12.548795
Publisher: SPIE
Date: 07-06-2007
DOI: 10.1117/12.724655
Publisher: SPIE
Date: 25-05-2004
DOI: 10.1117/12.549267
Publisher: Cold Spring Harbor Laboratory
Date: 29-03-2022
DOI: 10.1101/2022.03.28.486155
Abstract: Hip osteoarthritis (HOA) is a degenerative joint disease that leads to the progressive destruction of subchondral bone and cartilage at the hip joint. Development of effective treatments for HOA remains an open problem, primarily due to the lack of knowledge of its pathogenesis and a typically late-stage diagnosis. We describe a novel network analysis methodology for micro-computed tomography (micro-CT) images of human trabecular bone. We explored differences between the trabecular bone microstructure of femoral heads with and without HOA. Large-scale automated extraction of the network formed by trabecular bone revealed significant network properties not previously reported for bone. Profound differences were discovered, particularly in the proximal third of the femoral head, where HOA networks demonstrated elevated numbers of edges, vertices and graph components. When further differentiating healthy joint and HOA networks, the latter showed fewer small-world network properties, due to decreased clustering coefficient and increased characteristic path length. Furthermore, we found that HOA networks had reduced length of edges, indicating the formation of compressed trabecular structures. In order to assess our network approach, we developed a deep learning model for classifying HOA and control cases, and we fed it with two separate inputs: ( i ) micro-CT images of the trabecular bone, and ( ii ) the network extracted from them. The model with plain micro-CT images achieves 74.63% overall accuracy while the trained model with extracted networks attains 96.47% accuracy. We anticipate our findings to be a starting point for a novel description of bone microstructure in HOA, by considering the phenomenon from a graph theory viewpoint.
Publisher: SPIE
Date: 30-03-2004
DOI: 10.1117/12.549581
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2019
Publisher: SPIE
Date: 16-02-2005
DOI: 10.1117/12.582096
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 09-2014
Publisher: Oxford University Press (OUP)
Date: 11-2022
DOI: 10.1093/PNASNEXUS/PGAC258
Abstract: Hip osteoarthritis (HOA) is a degenerative joint disease that leads to the progressive destruction of subchondral bone and cartilage at the hip joint. Development of effective treatments for HOA remains an open problem, primarily due to the lack of knowledge of its pathogenesis and a typically late-stage diagnosis. We describe a novel network analysis methodology for microcomputed tomography (micro-CT) images of human trabecular bone. We explored differences between the trabecular bone microstructure of femoral heads with and without HOA. Large-scale automated extraction of the network formed by trabecular bone revealed significant network properties not previously reported for bone. Profound differences were discovered, particularly in the proximal third of the femoral head, where HOA networks demonstrated elevated numbers of edges, vertices, and graph components. When further differentiating healthy joint and HOA networks, the latter showed fewer small-world network properties, due to decreased clustering coefficient and increased characteristic path length. Furthermore, we found that HOA networks had reduced length of edges, indicating the formation of compressed trabecular structures. In order to assess our network approach, we developed a deep learning model for classifying HOA and control cases, and we fed it with two separate inputs: (i) micro-CT images of the trabecular bone, and (ii) the network extracted from them. The model with plain micro-CT images achieves 74.6% overall accuracy while the trained model with extracted networks attains 96.5% accuracy. We anticipate our findings to be a starting point for a novel description of bone microstructure in HOA, by considering the phenomenon from a graph theory viewpoint.
Publisher: SPIE
Date: 21-11-2001
DOI: 10.1117/12.449170
Publisher: World Scientific Pub Co Pte Lt
Date: 12-2004
DOI: 10.1142/S021947750400221X
Abstract: An analysis of Parrondo's games with different chaotic switching strategies is carried out. We generalize a fair way to compare between different switching strategies. The performance of Parrondo's games with chaotic switching strategies is compared to random and periodic switching strategies. The rate of winning of Parrondo's games with chaotic switching strategies depends on coefficient(s) defining the chaotic generator, initial conditions of the chaotic sequence and the proportion of Game A played. Maximum rate of winning can be obtained with all the above mentioned factors properly set, and this occurs when chaotic switching strategy approaches periodic-like behavior.
Publisher: The Royal Society
Date: 11-2019
DOI: 10.1098/RSOS.190671
Abstract: Many physical systems can be adequately modelled using a second-order approximation. Thus, the problem of system identification often reduces to the problem of estimating the position of a single pair of complex–conjugate poles. This paper presents a convenient but approximate technique for the estimation of the position of a single pair of complex–conjugate poles, using the moment of velocity (MoV). The MoV is a Hilbert transform based signal processing tool that addresses the shortcomings of instantaneous frequency. We demonstrate that the MoV can be employed for parameter identification of a dynamical system. We estimate the d ing coefficient and oscillation frequency via MoV of the impulse response.
Publisher: World Scientific Pub Co Pte Lt
Date: 12-2005
DOI: 10.1142/S021947750500294X
Abstract: This paper reviews applications of signal processing techniques to a number of areas in the field of genetics. We focus on techniques for analyzing DNA sequences, and briefly discuss applications of signal processing to DNA sequencing, and other related areas in genetics that can provide biologically significant information to assist with sequence analysis.
Publisher: Springer Science and Business Media LLC
Date: 24-09-2014
DOI: 10.1038/SREP06461
Abstract: The Kish key distribution system has been proposed as a classical alternative to quantum key distribution. The idealized Kish scheme elegantly promises secure key distribution by exploiting thermal noise in a transmission line. However, we demonstrate that it is vulnerable to nonidealities in its components, such as the finite resistance of the transmission line connecting its endpoints. We introduce a novel attack against this nonideality using directional wave measurements and experimentally demonstrate its efficacy.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 04-2014
Publisher: Springer Science and Business Media LLC
Date: 20-06-2019
DOI: 10.1038/S41598-019-45253-5
Abstract: The truel is a three person competition that generalises the classic duel. In this game three players try to eliminate each other in a series of one-to-one duels until there is only one survivor. The players’ marksmanship, shooting order and strategies for choosing a target play a significant role in in idual’s survival probability. Strategies such as shooting into the air (abstention), shooting at the strongest opponent, and shooting at the weakest opponent have been analysed in the previous literature. In this paper, for the first time, we consider suicidal and random strategies that can be chosen by the weaker player. We show that although there is no possible highest probability region for weakest player adopting suicidal strategy, the player may increase the survival probability via switching between suicidal and abstention strategies randomly. In addition, we demonstrate that there is a narrow survival area for the weakest player when the player aims randomly at two other opponents, and eventually the area fades away if the player fires randomly at himself or the other two opponents.
Publisher: Elsevier BV
Date: 03-2002
Publisher: F1000 Research Ltd
Date: 13-07-2015
DOI: 10.12688/F1000RESEARCH.6760.1
Abstract: Complete response (CR) rates reported for cytotoxic chemotherapy for late-stage cancer patients are generally low, with few exceptions, regardless of the solid cancer type or drug regimen. We investigated CR rates reported in the literature for clinical trials using chemotherapy alone, across a wide range of tumour types and chemotherapeutic regimens, to determine an overall CR rate for late-stage cancers. A total of 141 reports were located using the PubMed database. A meta-analysis was performed of reported CR from 68 chemotherapy trials (total 2732 patients) using standard agents across late-stage solid cancers—a binomial model with random effects was adopted. Mean CR rates were compared for different cancer types, and for chemotherapeutic agents with different mechanisms of action, using a logistic regression. Our results showed that the CR rates for chemotherapy treatment of late-stage cancer were generally low at 7.4%, regardless of the cancer type or drug regimen used. We found no evidence that CR rates differed between different chemotherapy drug types, but amongst different cancer types small CR differences were evident, although none exceeded a mean CR rate of 11%. This remarkable concordance of CR rates regardless of cancer or therapy type remains currently unexplained, and motivates further investigation.
Publisher: SPIE
Date: 25-05-2004
DOI: 10.1117/12.546637
Publisher: Public Library of Science (PLoS)
Date: 14-05-2015
Publisher: SPIE
Date: 28-12-2005
DOI: 10.1117/12.673126
Publisher: SPIE
Date: 29-03-2004
DOI: 10.1117/12.522203
Publisher: SPIE
Date: 23-05-2005
DOI: 10.1117/12.618664
Publisher: SPIE
Date: 08-05-2003
DOI: 10.1117/12.501497
Publisher: SPIE
Date: 29-03-2004
DOI: 10.1117/12.548001
Publisher: SPIE
Date: 25-05-2004
DOI: 10.1117/12.548122
Publisher: Public Library of Science (PLoS)
Date: 20-02-2013
Publisher: SPIE
Date: 02-05-2003
DOI: 10.1117/12.501494
Publisher: The Royal Society
Date: 03-2019
DOI: 10.1098/RSOS.182001
Abstract: The instantaneous frequency (IF) of a signal is a well-defined quantity that is widely used for analysing non-stationary signals. However, often in practice, IF as a function of time can possess large spikes and negative values. Moreover, IF is very sensitive to noise, limiting its range of practical application. Due to these deficiencies, we introduce the concept of moment of velocity (MoV) for signal analysis. As a case study, we compare the performance of MoV to a standard Hilbert transform-based approach for R-wave identification in human electrocardiogram signals, demonstrating that our approach is more robust to noise. We examine characteristic heartbeats obtained from the MIT-BIH Arrhythmia database. A detection error rate of 0.07%, a positive predictive value of 99.97%, and a sensitivity of 99.95% are achieved against analysis results from the database.
Publisher: SPIE
Date: 25-05-2004
DOI: 10.1117/12.546641
Publisher: The Royal Society
Date: 03-2016
Abstract: Is it possible for a large sequence of measurements or observations, which support a hypothesis, to counterintuitively decrease our confidence? Can unanimous support be too good to be true? The assumption of independence is often made in good faith however, rarely is consideration given to whether a systemic failure has occurred. Taking this into account can cause certainty in a hypothesis to decrease as the evidence for it becomes apparently stronger. We perform a probabilistic Bayesian analysis of this effect with ex les based on (i) archaeological evidence, (ii) weighing of legal evidence and (iii) cryptographic primality testing. In this paper, we investigate the effects of small error rates in a set of measurements or observations. We find that even with very low systemic failure rates, high confidence is surprisingly difficult to achieve in particular, we find that certain analyses of cryptographically important numerical tests are highly optimistic, underestimating their false-negative rate by as much as a factor of 2 80 .
Publisher: American Physical Society (APS)
Date: 24-11-2003
Publisher: SPIE
Date: 23-05-2005
DOI: 10.1117/12.622380
Publisher: IOP Publishing
Date: 20-05-2016
Publisher: Public Library of Science (PLoS)
Date: 28-02-2014
Publisher: AIP
Date: 2005
DOI: 10.1063/1.2138589
Publisher: SPIE
Date: 02-05-2003
DOI: 10.1117/12.484914
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2020
Publisher: SPIE
Date: 11-2002
DOI: 10.1117/12.469071
Publisher: IEEE
Date: 10-2014
Publisher: SPIE
Date: 25-05-2004
DOI: 10.1117/12.561307
Publisher: SPIE
Date: 16-03-2001
DOI: 10.1117/12.418769
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2023
No related grants have been discovered for Andrew Allison.