Australian Research Council (ARC)

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This is a collection of ARC-funded research publications authored by Flinders academics.

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    Towards a brain-controlled Wheelchair Prototype
    (BCS, 2010) Yazdani, Naisan ; Khazab, Fatemah ; Fitzgibbon, Sean Patrick ; Luerssen, Martin Holger ; Powers, David Martin ; Clark, Christopher Richard
    In this project, a design for a non-invasive, EEG-based braincontrolled wheelchair has been developed for use by completely paralyzed patients. The proposed design includes a novel approach for selecting optimal electrode positions, a series of signal processing algorithms and an interface to a powered wheelchair. In addition, a 3D virtual environment has been implemented for training, evaluating and testing the system prior to establishing the wheelchair interface. Simulation of a virtual scenario replicating the real world gives subjects an opportunity to become familiar with operating the device prior to engaging the wheelchair.
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    Multiplying the Mileage of Your Dataset with Subwindowing
    (Springer Berlin Heidelberg, 2011) Atyabi, Adham ; Fitzgibbon, Sean Patrick ; Powers, David Martin
    This study is focused on improving the classification performance of EEG data through the use of some data restructuring methods. In this study, the impact of having more training instances/samples vs. using shorter window sizes is investigated. The BCI2003 IVa dataset is used to examine the results. The results not surprisingly indicate that, up to a certain point, having higher numbers of training instances significantly improves the classification performance while the use of shorter window sizes tends to worsen performance in a way that usually cannot fully be compensated for by the additional instances, but tends to provide useful gain in overall performance for small divisors into two or three subepochs. We have moreover determined that use of an incomplete set of overlapping windows can have little effect, and is inapplicable for the smallest divisors, but that use of overlapping subepochs from three specific non-overlapping areas (start, middle and end) of a superepoch tends to contribute significant additional information. Examination of a division into five equal non-overlapping areas indicates that for some subjects the first or last fifth contributes significantly less information than the middle three fifths.
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    Evaluation: from Precision, Recall and F-measure to ROC, Informedness, Markedness and Correlation
    (Bioinfo Publications, 2011-12-15) Powers, David Martin
    Commonly used evaluation measures including Recall, Precision, F-Measure and Rand Accuracy are biased and should not be used without clear understanding of the biases, and corresponding identification of chance or base case levels of the statistic. Using these measures a system that performs worse in the objective sense of Informedness, can appear to perform better under any of these commonly used measures. We discuss several concepts and measures that reflect the probability that prediction is informed versus chance. Informedness and introduce Markedness as a dual measure for the probability that prediction is marked versus chance. Finally we demonstrate elegant connections between the concepts of Informedness, Markedness, Correlation and Significance as well as their intuitive relationships with Recall and Precision, and outline the extension from the dichotomous case to the general multi-class case.
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    Multiplication of EEG Samples through Replicating, Biasing, and Overlapping
    (Springer Berlin Heidelberg, 2012) Atyabi, Adham ; Fitzgibbon, Sean Patrick ; Powers, David Martin
    EEG recording is a time consuming operation during which the subject is expected to stay still for a long time performing tasks. It is reasonable to expect some uctuation in the level of focus toward the performed task during the task period. This study is focused on investi- gating various approaches for emphasizing regions of interest during the task period. Dividing the task period into three segments of beginning, middle and end, is expectable to improve the overall classi cation per- formance by changing the concentration of the training samples toward regions in which subject had better concentration toward the performed tasks. This issue is investigated through the use of techniques such as i) replication, ii) biasing, and iii) overlapping. A dataset with 4 motor imagery tasks (BCI Competition III dataset IIIa) is used. The results il- lustrate the existing variations within the potential of di erent segments of the task period and the feasibility of techniques that focus the training samples toward such regions.
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    The problem with Kappa
    (Association for Computational Linguistics, 2012-04) Powers, David Martin
    It is becoming clear that traditional evaluation measures used in Computational Linguistics (including Error Rates, Accuracy, Recall, Precision and F-measure) are of limited value for unbiased evaluation of systems, and are not meaningful for comparison of algorithms unless both the dataset and algorithm parameters are strictly controlled for skew (Prevalence and Bias). The use of techniques originally designed for other purposes, in particular Receiver Operating Characteristics Area Under Curve, plus variants of Kappa, have been proposed to fill the void. This paper aims to clear up some of the confusion relating to evaluation, by demonstrating that the usefulness of each evaluation method is highly dependent on the assumptions made about the distributions of the dataset and the underlying populations. The behaviour of a number of evaluation measures is compared under common assumptions. Deploying a system in a context which has the opposite skew from its validation set can be expected to approximately negate Fleiss Kappa and halve Cohen Kappa but leave Powers Kappa unchanged. For most performance evaluation purposes, the latter is thus most appropriate, whilst for comparison of behaviour, Matthews Correlation is recommended.
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    Remembrance of games past: the Popular Memory Archive
    (ACM Digital Library, 2013) Stuckey, Helen ; Swalwell, Melanie Lorraine ; Ndalianis, Angela ; de Vries, Denise Bernadette
    Games are one of the most significant cultural forms of our times and yet they are poorly documented in Australia and New Zealand. Knowledge about the history of games is overwhelmingly held by private collectors and fans, with ephemera and other primary sources located amongst the general public. This paper presents and discusses the Popular Memory Archive (PMA), an online portal of the "Play It Again" game history and preservation project. As well as providing a way to disseminate some of the team's research, the PMA taps into what is, effectively, a collective public archive by providing a technique for collecting information, resources and memories from the public about 1980s computer games. Digital games are more than inert code; they come to life in the act of play. Collecting games and other artefacts and preserving them is thus only part of the construction of a history about games. The PMA is designed to work with online retro gamer communities and fans, and this paper reflects on the PMA as a method for collecting the memories of those who lived and played their way through this period.
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    Moving on from the original experience: games history, preservation and presentation
    (Digital Games Research Association, 2013) Swalwell, Melanie Lorraine
    The art historical notion of ‘the original’ continues to inflect games history and game preservation work. This paper notes the persistence of this concept particularly in the game lover’s invocation of ‘the original experience’. The paper first traces the game lover’s notions of history and preservation, recognizing their commitment to games, before noting that the appeal to original experience is problematic for more critical historical and scholarly perspectives. It suggests that there is a need to liberate critical thought from this paradigm and ask different questions, such as how exhibitions of 1980s games and gaming culture might be assembled for future audiences with no memory of this period. The model proposed by net art preservationist, Anne Laforet, of the Archaeological Museum offers a way for thinking about such exhibits of game history and visitors’ encounters with these, whilst moving beyond the notion that games must play exactly as they once did.
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    Collecting and conserving code: challenges and strategies
    (Department of Media, Music, Communication and Cultural Studies, Macquarie University, Sydney, 2013) Swalwell, Melanie Lorraine ; de Vries, Denise Bernadette
    The collection and conservation of code is still in its infancy in Australia. Even where coded items do exist, they are almost completely invisible within local cultural institutions and archives. Born-digital heritage faces unique risks - the degradation of hardware and software, obsolete operating systems, and intellectual property laws that restrict digital preservation activities. Too often, governments and cultural institutions either fail to recognise the precarious situation of historic code-based media, or are not able to respond in an appropriate fashion, due to a lack of resources, know-how, or sometimes, will. After outlining some of the challenges - for institutions and researchers - of developing collections of games and other software, this article will detail two current research initiatives. The Play It Again project is conducting research into the largely unknown histories of 1980s game development in Australia and New Zealand, ensuring that local titles are documented, preserved and make it into national collections. The Australasian Heritage Software Database seeks to: draw together existing knowledge about locally-developed software, marshal a network of supporters, and develop an enabling discourse that supports research into histories of software and digital preservation. Whilst these projects do not provide complete solutions by any means, a local discourse about the importance of collecting and conserving code is emerging.
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    The Popular Memory Archive: collecting and exhibiting player culture from the 1980s
    (Springer-Verlag Berlin Heidelberg, 2013) Stuckey, Helen ; Swalwell, Melanie Lorraine ; Ndalianis, Angela
    This book constitutes the refereed post-proceedings of the IFIP WG 9.7 International Conference on the History of Computing, HC 2013, held in London, UK, in June 2013. The 29 revised full papers presented were carefully reviewed and selected from numerous submissions. The papers cover a wide range of topics related to the history of computing and offer a number of different approaches to making this history relevant. These range from discussion of approaches to describing and analyzing the history through storytelling and education to description of various collections, working installations and reconstruction projects.
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    The Popular Memory Archive
    (Flinders University, Department of Screen and Media, 2013) de Vries, Denise Bernadette ; Ndalianis, Angela ; Stuckey, Helen ; Swalwell, Melanie Lorraine
    Digital games make up a significant but little known chapter in the history of the moving image in Australia and New Zealand. This site aims to exhibit some of the significant local games of the 1980s era, and collect documentation in order to remember early games through popular memory. It features a curated exhibition of information about fifty 1980s Australian and New Zealand Games, and the Creators and Companies behind them.
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    An online means of testing asymmetries in seating preference reveals a bias for airplanes and theatres
    (SAGE, 2013) Nicholls, Michael Elmo Richard ; Thomas, Nicole A ; Loetscher, Tobias
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    Miocene mystacinids (Chiroptera: Noctilionoidea) indicate a long history for endemic bats in New Zealand
    (Society of Vertebrate Paleontology, 2013) Hand, S ; Worthy, Trevor ; Archer, M ; Worthy, J ; Tennyson, A ; Schofield, R
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    Early Miocene fossil frogs (Anura: Leiopelmatidae) from New Zealand.
    (Taylor & Francis, 2013) Worthy, Trevor ; Tennyson, Alan J D ; Scofield, R Paul ; Hand, Suzanne J
    The first pre-Quaternary anurans from New Zealand are reported from the Early Miocene (19–16 Ma) St Bathans Fauna based on 10 fossil bones. Four bones representing two new species differing in size are described in Leiopelma: Leiopelmatidae, and are the first Tertiary records for the family. Six indeterminate frog fossils are morphologically similar to leiopelmatids and represent two species consistent in size with those known from diagnostic material. These records are highly significant, as minimally, they reduce the duration of the leiopelmatid ‘ghost lineage’ by c.20 million years and demonstrate that a diversity of leiopelmatids has long been present on New Zealand, supporting the ancient dichotomy of the extant species based on molecular data.
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    Miocene fossils show that kiwi (Apteryx, Apterygidae) are probably not phyletic dwarves
    (Verlag Naturhistorisches Museum Wien, 2013) Worthy, Trevor ; Worthy, Jennifer P ; Tennyson, Alan J D ; Salisbury, Steven W ; Hand, Suzanne J ; Scofield, R Paul
    Until now, kiwi (Apteryx, Apterygidae) have had no pre-Quaternary fossil record to inform on the timing of their arrival in New Zealand or on their inter-ratite relationships. Here we describe two fossils in a new genus of apterygid from Early Miocene sediments at St Bathans, Central Otago, minimally dated to 19–16 Ma. The new fossils indicate a markedly smaller and possibly volant bird, supporting a possible overwater dispersal origin to New Zealand of kiwi independent of moa. If the common ancestor of this early Miocene apterygid species and extant kiwi was similarly small and volant, then the phyletic dwarfing hypothesis to explain relatively small body size of kiwi compared with other ratites is incorrect. Apteryx includes five extant species distributed on North, South, Stewart and the nearshore islands of New Zealand. They are nocturnal, flightless and comparatively large birds, 1–3 kg, with morphological attributes that reveal an affinity with ratites, but others, such as their long bill, that differ markedly from all extant members of that clade. Although kiwi were long considered most closely related to sympatric moa (Dinornithiformes), all recent analyses of molecular data support a closer affinity to Australian ratites (Casuariidae). Usually assumed to have a vicariant origin in New Zealand (ca 80–60 Ma), a casuariid sister group relationship for kiwi, wherein the common ancestor was volant, would more easily allow a more recent arrival via overwater dispersal.
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    A bittern (Aves: Ardeidae) from the Early Miocene of New Zealand
    (Springer Verlag, 2013) Worthy, Trevor ; Worthy, Jennifer P ; Tennyson, Alan J D ; Scofield, R Paul
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    Surface Laplacian of Central Scalp Electrical Signals is Insensitive to Muscle Contamination
    (IEEE - Institute of Electrical and Electronics, 2013-01) Fitzgibbon, Sean Patrick ; Lewis, Trent Wilson ; Powers, David Martin ; Whitham, Emma Mary ; Willoughby, John Osborne ; Pope, Kennith
    Abstract—Objective: To investigate the effects of surface Laplacian processing on gross and persistent electromyographic (EMG) contamination of electroencephalographic (EEG) signals in electrical scalp recordings. Methods: We made scalp recordings during passive and active tasks, on awake subjects in the absence and in the presence of complete neuromuscular blockade. Three scalp surface Laplacian estimators were compared to left ear and common average reference (CAR). Contamination was quantified by comparing power after paralysis (brain signal, B) with power before paralysis (brain plus muscle signal, B+M). Brain:Muscle (B:M) ratios for the methods were calculated using B and differences in power after paralysis to represent muscle (M). Results: There were very small power differences after paralysis up to 600 Hz using surface Laplacian transforms (B:M> 6 above 30 Hz in central scalp leads). Conclusions: Scalp surface Laplacian transforms reduce muscle power in central and peri-central leads to less than one sixth of the brain signal, 2-3 times better signal detection than CAR. Significance: Scalp surface Laplacian transformations provide robust estimates for detecting high frequency (gamma) activity, for assessing electrophysiological correlates of disease, and also for providing a measure of brain electrical activity for use as a ‘standard’ in the development of brain/muscle signal separation methods.
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    A computationally and cognitively plausible model of supervised and unsupervised learning
    (Springer-Verlag, 2013-01-01) Powers, David Martin
    The issue of chance correction has been discussed for many decades in the context of statistics, psychology and machine learning, with multiple measures being shown to have desirable properties, including various definitions of Kappa or Correlation, and the psychologically validated ΔP measures. In this paper, we discuss the relationships between these measures, showing that they form part of a single family of measures, and that using an appropriate measure can positively impact learning.
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    The interplay between structure and agency in shaping the mental health consequences of job loss
    (BioMed Central Ltd., 2013-02-06) Anaf, Julia Margaret ; Baum, Fran ; Newman, Lareen Ann ; Ziersch, Anna Marie ; Jolley, Gwyneth Margaret
    Main themes that emerged from the qualitative exploration of the psychological distress of job loss included stress, changes to perceived control, loss of self-esteem, shame and loss of status, experiencing a grieving process, and financial strain. Drawing on two models of agency we identified the different ways workers employed their agency, and how their agency was enabled, but mainly constrained, when dealing with job loss consequences. Respondents’ accounts support the literature on the moderating effects of economic resources such as redundancy packages. The results suggest the need for policies to put more focus on social, emotional and financial investment to mediate the structural constraints of job loss. Our study also suggests that human agency must be understood within an individual’s whole of life circumstances, including structural and material constraints, and the personal or interior factors that shape these circumstances.
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    The nature and correlates of self-esteem trajectories in late life
    (American Psychology Association, 2013-07) Wagner, Jenny ; Gerstorf, Denis ; Hoppmann, Christiane A ; Luszcz, Mary Alice
    Is it possible to maintain a positive perspective on the self into very old age? Empirical research so far is rather inconclusive, with some studies reporting substantial declines in self-esteem late in life, whereas others report relative stability into old age. In this article, we examine long-term change trajectories in self-esteem in old age and very old age and link them to key correlates in the health, cognitive, self-regulatory, and social domains. To do so, we estimated growth curve models over chronological age and time-to-death using 18-year longitudinal data from the Australian Longitudinal Study of Ageing (N = 1,215; age 65–103 years at first occasion; M = 78.8 years, SD = 5.9; women: 45% of sample). Results revealed that self-esteem was, on average, fairly stable with minor declines only emerging in advanced ages and at the very end of life. Examination of the vast between-person differences revealed that lower cognitive abilities and lower perceived control independently related to lower self-esteem. Also, lower cognitive abilities were associated with steeper age-related and mortality-related self-esteem decrements. In our discussion, we consider a variety of challenges that potentially shape self-esteem late in life and highlight the need for more mechanism-oriented research to better understand the pathways underlying stability and change in self-esteem.
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    On sets of occupational measures generated by a deterministic control system on an infinite time horizon
    (Elsevier, 2013-09) Gaitsgory, Vladimir ; Quincampoix, Marc
    We give a representation for the closed convex hull of the set of discounted occupational measures generated by control-state trajectories of a deterministic control system. We also investigate the limit behavior of the latter when the discount factor tends to zero and compare it with the limit behavior of the long run time average occupational measures set. The novelty of our results is in that we allow the control set dependence on the state variables that make the results to be applicable to differential inclusions.