454 resultados para digital signal


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Age-related Macular Degeneration (AMD) is one of the major causes of vision loss and blindness in ageing population. Currently, there is no cure for AMD, however early detection and subsequent treatment may prevent the severe vision loss or slow the progression of the disease. AMD can be classified into two types: dry and wet AMDs. The people with macular degeneration are mostly affected by dry AMD. Early symptoms of AMD are formation of drusen and yellow pigmentation. These lesions are identified by manual inspection of fundus images by the ophthalmologists. It is a time consuming, tiresome process, and hence an automated diagnosis of AMD screening tool can aid clinicians in their diagnosis significantly. This study proposes an automated dry AMD detection system using various entropies (Shannon, Kapur, Renyi and Yager), Higher Order Spectra (HOS) bispectra features, Fractional Dimension (FD), and Gabor wavelet features extracted from greyscale fundus images. The features are ranked using t-test, Kullback–Lieber Divergence (KLD), Chernoff Bound and Bhattacharyya Distance (CBBD), Receiver Operating Characteristics (ROC) curve-based and Wilcoxon ranking methods in order to select optimum features and classified into normal and AMD classes using Naive Bayes (NB), k-Nearest Neighbour (k-NN), Probabilistic Neural Network (PNN), Decision Tree (DT) and Support Vector Machine (SVM) classifiers. The performance of the proposed system is evaluated using private (Kasturba Medical Hospital, Manipal, India), Automated Retinal Image Analysis (ARIA) and STructured Analysis of the Retina (STARE) datasets. The proposed system yielded the highest average classification accuracies of 90.19%, 95.07% and 95% with 42, 54 and 38 optimal ranked features using SVM classifier for private, ARIA and STARE datasets respectively. This automated AMD detection system can be used for mass fundus image screening and aid clinicians by making better use of their expertise on selected images that require further examination.

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This research is focused on realizing productivity benefits for the delivery of transport infrastructure in the Australian construction industry through the use of building information modeling (BIM), virtual design and construction (VDC) and integrated project delivery (IPD). Specific objectives include: (I) building an understanding of the institutional environment, business systems and support mechanisms (e.g., training and skilling) which impact on the uptake of BIM/VDC; (II) gathering data to undertake a cross-country analysis of these environments; and (III) providing strategic and practical outcomes to guide the uptake of such processes in Australia. Activities which will inform this research include a review of academic literature and industry documentation, semi-formal interviews in Australia and Sweden, and a cross-country comparative analysis to determine factors affecting uptake and associated productivity improvements. These activities will seek to highlight the gaps between current-practice and best-practice which are impacting on widespread adoption of BIM/VDC and IPD. Early findings will be discussed with intended outcomes of this research being used to: inform a national public procurement strategy; provide guidelines for new contractual frameworks; and contribute to closing skill gaps. Keywords: building information modeling (BIM); virtual design and construction (VDC); integrated project delivery (IPD); transport infrastructure; Australia; procurement

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The competent leadership of digital transformation needs to involve the board of directors. The reported lack of such capability in boards is becoming a pressing issue. A part of leadership in such transformation is the board of director’s competence to lead Enterprise Business Technology Governance (EBTG). In this paper we take the position that EBTG competencies are essential in boards, because competent EBTG has been shown to contribute to increased revenue, profit, and returns. We update and expand on the results of a multi-method approach to the development of a set of three board of director competencies needed for effective EBTG.

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A field oriented control (FOC) algorithm is simulated and implemented for use with a permanent magnet synchronous motor (PMSM). Rotor position is sensed using Hall effect switches on the stator because other hardware position sensors attached to the rotor may not be desirable or cost effective for certain applications. This places a limit on the resolution of position sensing – only a few Hall effect switches can be placed. In this simulation, three sensors are used and the position information is obtained at higher resolution by estimating it from the rotor dynamics, as shown in literature previously. This study compares the performance of the method with an incremental encoder using simulations. The FOC algorithm is implemented using Digital Motor Control (DMC) and IQ Texas Instruments libraries from a Simulink toolbox called Embedded Coder, and downloaded into a TI microcontroller (TMS320F28335) known as the Piccolo via Code Composer Studio (CCS).

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Australia has had two recent public apologies, one to the ‘ Stolen Generation’ of Aboriginal and Torres Strait Islander Australians and the second to the ‘Forgotten Australians' – people who had been removed from their parents as children and institutionalized. Both acts occurred in time when there was no Internet and peoples’ stories took years to collect and decades for their weight to carry the public momentum required to gain a public apology. Now, in a digital age, the reports and the testimonies held within them are available for all to read on the Internet. We all now know what happened and formal public apologies ensued. Both public apologies also draw attention to an emerging intersection between digital technologies, personal historical stories and public apology. Research has identified the potential of digital narrative, such as digital storytelling3 and videoed oral histories to assist in the production of digital narratives that can help to present the multiple voices and viewpoints of those affected by these subjects co-creatively (Burgess et al, pp.152-153). Not all Australians however have access or the skills to use digital tools so as to benefit from these technologies ⎯ especially Indigenous Australians. While the Federal Government is committed to helping Australians enjoy digital confidence and digital media literacy skills, experience inclusive digital participation and benefit through online engagement (Department of Broadband, communications and the Digital Economy, 2009) there are many initiatives that can also be undertaken locally by State funded institutions, such as libraries to assist. This paper highlights the outcomes of recent empirical projects undertaken at the State Library of Queensland (SLQ) in particular focusing on digital initiatives in Family History practices by Indigenous users, and a digital story project in response to the public apology to the Stolen Generation instigated by SLQ.

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This paper examines the capacity of digital storytelling to document research activity in the creative and performing arts. In particular, it seeks to identify the thought processes and methods that underpin this research and to capture them using the digital storytelling medium. Interest in this issue was prompted by the author’s work with the creative and performing artists from the Queensland Conservatorium and the Queensland College of Art as part of the Federal government’s Research Quality Framework (RQF) in 2007. The RQF compelled artists to address what it means to undertake research in their disciplines, to describe this, measure it and quantify it; for many practitioners this represents a significant challenge. These issues continue to be pertinent in the context of the Excellence in Research for Australia (ERA) initiative. This research is significant because it seeks to identify, in layman’s terms, the research methods and thought processes used by artists in their research practice. It seeks to do so free of the encumbrances of the professional doctorate policies, the higher education research quality frameworks, and the dense philosophical debates that have to-date dominated discussions of this issue. The research involves qualitative data collection methods including a detailed literature review, interviews with key practitioners and academics involved in the creative and performing arts, and three case studies. The literature review focuses on publications that explore issues of research practice and method in the creative and performing arts. The case studies involve three Queensland-based artists. Digital stories will be developed (and presented) with Marcus and Mafe using their visual materials and drawing on the issues identified in the literature review and interviews. Emmerson’s DVD provided a point of comparison with the digital stories. (Brief bios are attached)

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The stop-signal paradigm is increasingly being used as a probe of response inhibition in basic and clinical neuroimaging research. The critical feature of this task is that a cued response is countermanded by a secondary ‘stop-signal’ stimulus offset from the first by a ‘stop-signal delay’. Here we explored the role of task difficulty in the stop-signal task with the hypothesis that what is critical for successful inhibition is the time available for stopping, that we define as the difference between stop-signal onset and the expected response time (approximated by reaction time from previous trial). We also used functional magnetic resonance imaging (fMRI) to examine how the time available for stopping affects activity in the putative right inferior frontal gyrus and presupplementary motor area (right IFG-preSMA) network that is known to support stopping. While undergoing fMRI scanning, participants performed a stop-signal variant where the time available for stopping was kept approximately constant across participants, which enabled us to compare how the time available for stopping affected stop-signal task difficulty both within and between subjects. Importantly, all behavioural and neuroimaging data were consistent with previous findings. We found that the time available for stopping distinguished successful from unsuccessful inhibition trials, was independent of stop-signal delay, and affected successful inhibition depending upon individual SSRT. We also found that right IFG and adjacent anterior insula were more strongly activated during more difficult stopping. These findings may have critical implications for stop-signal studies that compare different patient or other groups using fixed stop-signal delays.

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Inhibitory control deficits are well documented in schizophrenia, supported by impairment in an established measure of response inhibition, the stop-signal reaction time (SSRT). We investigated the neural basis of this impairment by comparing schizophrenia patients and controls matched for age, sex and education on behavioural, functional magnetic resonance imaging (fMRI) and event-related potential (ERP) indices of stop-signal task performance. Compared to controls, patients exhibited slower SSRT and reduced right inferior frontal gyrus (rIFG) activation, but rIFG activation correlated with SSRT in both groups. Go stimulus and stop-signal ERP components (N1/P3) were smaller in patients, but the peak latencies of stop-signal N1 and P3 were also delayed in patients, indicating impairment early in stop-signal processing. Additionally, response-locked lateralised readiness potentials indicated response preparation was prolonged in patients. An inability to engage rIFG may predicate slowed inhibition in patients, however multiple spatiotemporal irregularities in the networks underpinning stop-signal task performance may contribute to this deficit.

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Teachers’ beliefs about what it is (or is not) possible to achieve with digital games in educational contexts will inevitably influence the decisions that they make about how, when, and for what specific purposes they will bring these games into their classrooms. They play a crucial role in both shaping and responding to the complex contextual factors which influence how games are understood and experienced in educational settings. Throughout this article the authors draw upon data collected for a large-scale, mixed-methods research project focusing on literacy, learning and teaching with digital games in Australian classrooms, to focus explicitly on the attitudes,understandings and expectations held about digital games by diverse teachers at the beginning of the project. They seek to identify the beliefs about games that motivated teachers’ participation in a digital games research project while focusing, as well, on concerns that teachers express about risks or limitations of such a project. The authors’ aim is to develop a detailed picture of the mindsets that teachers bring to games-based learning environments, and the relevance of these mindsets to broader debates about the relationship between games, learning and school.

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The along-track stereo images of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor with 15 m resolution were used to generate Digital Elevation Model (DEM) on an area with low and near Mean Sea Level (MSL) elevation in Johor, Malaysia. The absolute DEM was generated by using the Rational Polynomial Coefficient (RPC) model which was run on ENVI 4.8 software. In order to generate the absolute DEM, 60 Ground Control Pointes (GCPs) with almost vertical accuracy less than 10 meter extracted from topographic map of the study area. The assessment was carried out on uncorrected and corrected DEM by utilizing dozens of Independent Check Points (ICPs). Consequently, the uncorrected DEM showed the RMSEz of ± 26.43 meter which was decreased to the RMSEz of ± 16.49 meter for the corrected DEM after post-processing. Overall, the corrected DEM of ASTER stereo images met the expectations.

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This study aims to assess the accuracy of Digital Elevation Model (DEM) which is generated by using Toutin’s model. Thus, Toutin’s model was run by using OrthoEngineSE of PCI Geomatics 10.3.Thealong-track stereoimages of Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) sensor with 15 m resolution were used to produce DEM on an area with low and near Mean Sea Level (MSL) elevation in Johor Malaysia. Despite the satisfactory pre-processing results the visual assessment of the DEM generated from Toutin’s model showed that the DEM contained many outliers and incorrect values. The failure of Toutin’s model may mostly be due to the inaccuracy and insufficiency of ASTER ephemeris data for low terrains as well as huge water body in the stereo images.

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Edited by thought leaders of the fields of urban informatics and urban interaction design, this book brings together case studies and examples from around the world to discuss the role that urban Interfaces, citizen action, and city making play in the quest to create and maintain not only secure and resilient, but productive, sustainable, and liveable urban environments. The book debates the impact of these trends on theory, policy, and practice. The chapters in this book are sourced from blind peer reviewed contributions by leading researchers working at the intersection of the social / cultural, technical / digital, and physical / spatial domains of urbanism scholarship. The book appeals not only to research colleagues and students, but also to a vast number of practitioners in the private and public sector interested in accessible accounts that clearly and rigorously analyse the affordances and possibilities of urban interfaces, mobile technology, and location-based services to engage people towards open, smart and participatory urban environments.