Robust image hashing using higher order spectral features

Robust image hashing seeks to transform a given input image into a shorter hashed version using a key-dependent non-invertible transform. These image hashes can be used for watermarking, image integrity authentication or image indexing for fast retrieval. This paper introduces a new method of generating image hashes based on extracting Higher Order Spectral features from the Radon projection of an input image. The feature extraction process is non-invertible, non-linear and different hashes can be produced from the same image through the use of random permutations of the input. We show that the transform is robust to typical image transformations such as JPEG compression, noise, scaling, rotation, smoothing and cropping. We evaluate our system using a verification-style framework based on calculating false match, false non-match likelihoods using the publicly available Uncompressed Colour Image database (UCID) of 1320 images. We also compare our results to Swaminathan’s Fourier-Mellin based hashing method with at least 1% EER improvement under noise, scaling and sharpening.

Subjective blur limits for higher order aberrations

Purpose: We compared subjective blur limits for defocus and the higher-order aberrations of coma, trefoil, and spherical aberration. ---------- Methods: Spherical aberration was presented in both Zernike and Seidel forms. Black letter targets (0.1, 0.35, and 0.6 logMAR) on white backgrounds were blurred using an adaptive optics system for six subjects under cycloplegia with 5 mm artificial pupils. Three blur criteria of just noticeable, just troublesome, and just objectionable were used.---------- Results: When expressed as wave aberration coefficients, the just noticeable blur limits for coma and trefoil were similar to those for defocus, whereas the just noticeable limits for Zernike spherical aberration and Seidel spherical aberration (the latter given as an “rms equivalent”) were considerably smaller and larger, respectively, than defocus limits.---------- Conclusions: Blur limits increased more quickly for the higher order aberrations than for defocus as the criterion changed from just noticeable to just troublesome and then to just objectionable.

Infrastructure asset management: The challenges and approaches

Infrastructure organisations such as airport, seaport, rail and road are operating in an increasingly challenging business environment as a result of globalisation, privatisation and deregulation. These organisations must ensure that their main resource i.e. their infrastructure assets are well managed in order to support their business operations. Brisbane Airport is used as a case study to understand the challenges faced in the management of infrastructure assets as well as the approaches used to overcome them. The findings can be useful in helping asset managers to identify the resources they should seek to manipulate in order to make improvement to their activities and contribute to the overall performance of their organisation.

Colonising Shakespeare? : agency and authority in Gregory Rogers's Shakespearean picture books

“You need to be able to tell stories. Illustration is a literature, not a pure fine art. It’s the fine art of writing with pictures.” – Gregory Rogers. This paper reads two recent wordless picture books by Australian illustrator Gregory Rogers in order to consider how “Shakespeare” is produced as a complex object of consumption for the implied child reader: The Boy, The Bear, The Baron, The Bard (2004) and Midsummer Knight (2006). In these books other worlds are constructed via time-travel and travel to a fantasy world, and clearly presume reader competence in narrative temporality and structure, and cultural literacy (particularly in reference to Elizabethan London and William Shakespeare), even as they challenge normative concepts via use of the fantastic. Exploring both narrative sequences and individual images reveals a tension in the books between past and present, and real and imagined. Where children’s texts tend to privilege Shakespeare, the man and his works, as inherently valuable, Rogers’s work complicates any sense of cultural value. Even as these picture books depend on a lexicon of Shakespearean images for meaning and coherence, they represent William Shakespeare as both an enemy to children (The Boy), and a national traitor (Midsummer). The protagonists, a boy in the first book and the bear he rescues in the second, effect political change by defeating Shakespeare. However, where these texts might seem to be activating a postcolonial cultural critique, this is complicated both by presumed readerly competence in authorized cultural discourses and by repeated affirmation of monarchies as ideal political systems. Power, then, in these picture books is at once rewarded and withheld, in a dialectic of (possibly postcolonial) agency, and (arguably colonial) subjection, even as they challenge dominant valuations of “Shakespeare” they do not challenge understandings of the “Child”.

Anthony Browne and the cultural capital of classic fairy tales

Prolific British author/illustrator Anthony Browne both participates in the classic fairy-tale tradition and appropriates its cultural capital, ultimately undertaking a process of self-canonisation alongside the dissemination of fairy tales. In reading Browne’s Hansel and Gretel (1981), The Tunnel (1989) and Into the Forest (2004), a trajectory emerges that moves from broadly intertextual to more exclusively self-referential modes of representation which reward readers of “Anthony Browne”, rather than readers of “fairy tales”. All three books depict ‘babes in the woods’ stories wherein child characters must negotiate some form of threat outside the home in order to return home safely. Thus, they represent childhood agency. However, these visions of agency are ultimately subordinated to logics of capital, which means that child readers of Browne’s fairy-tale books are overtly invited to identify with children who act, but are interpellated as privileged if they ‘know’. Bourdieu’s model of ‘cultural capital’ offers a lens for considering Browne’s production of ‘value’ for his own works within a broader cultural landscape which privileges literary fairy tales as a register of juvenile cultural competency. If cultural capital can be formulated most simply as the symbolic exchange value of approved modes of knowing and being, it is clearly helpful when trying to unpack logics of meaning within heavily intertextual or citational texts. It is also helpful thinking about what kinds of stories we as a culture choose to disseminate, choose to privilege, or choose to suppress. Zipes notes of fairy tales that, “the genre itself becomes a kind of institute that is involved in the socialization and acculturation of readers” (22). He elaborates that, “We initiate readers and expect them to learn the fairy-tale code as part of our responsibility in the civilizing process” (Zipes 29), so it is little wonder that Tatar describes fairy tales as “a vital part of our cultural capital” (xix). Although Browne is clearly interested in literary fairy tales, the most obvious strategies of self-canonisation take place in Browne’s work not in words but in pictures: hidden in plain sight, as illustration becomes self-reflexive citation.

Analysis of cardiac and epileptic signals using higher order spectra

The theory of nonlinear dyamic systems provides some new methods to handle complex systems. Chaos theory offers new concepts, algorithms and methods for processing, enhancing and analyzing the measured signals. In recent years, researchers are applying the concepts from this theory to bio-signal analysis. In this work, the complex dynamics of the bio-signals such as electrocardiogram (ECG) and electroencephalogram (EEG) are analyzed using the tools of nonlinear systems theory. In the modern industrialized countries every year several hundred thousands of people die due to sudden cardiac death. The Electrocardiogram (ECG) is an important biosignal representing the sum total of millions of cardiac cell depolarization potentials. It contains important insight into the state of health and nature of the disease afflicting the heart. Heart rate variability (HRV) refers to the regulation of the sinoatrial node, the natural pacemaker of the heart by the sympathetic and parasympathetic branches of the autonomic nervous system. Heart rate variability analysis is an important tool to observe the heart's ability to respond to normal regulatory impulses that affect its rhythm. A computerbased intelligent system for analysis of cardiac states is very useful in diagnostics and disease management. Like many bio-signals, HRV signals are non-linear in nature. Higher order spectral analysis (HOS) is known to be a good tool for the analysis of non-linear systems and provides good noise immunity. In this work, we studied the HOS of the HRV signals of normal heartbeat and four classes of arrhythmia. This thesis presents some general characteristics for each of these classes of HRV signals in the bispectrum and bicoherence plots. Several features were extracted from the HOS and subjected an Analysis of Variance (ANOVA) test. The results are very promising for cardiac arrhythmia classification with a number of features yielding a p-value < 0.02 in the ANOVA test. An automated intelligent system for the identification of cardiac health is very useful in healthcare technology. In this work, seven features were extracted from the heart rate signals using HOS and fed to a support vector machine (SVM) for classification. The performance evaluation protocol in this thesis uses 330 subjects consisting of five different kinds of cardiac disease conditions. The classifier achieved a sensitivity of 90% and a specificity of 89%. This system is ready to run on larger data sets. In EEG analysis, the search for hidden information for identification of seizures has a long history. Epilepsy is a pathological condition characterized by spontaneous and unforeseeable occurrence of seizures, during which the perception or behavior of patients is disturbed. An automatic early detection of the seizure onsets would help the patients and observers to take appropriate precautions. Various methods have been proposed to predict the onset of seizures based on EEG recordings. The use of nonlinear features motivated by the higher order spectra (HOS) has been reported to be a promising approach to differentiate between normal, background (pre-ictal) and epileptic EEG signals. In this work, these features are used to train both a Gaussian mixture model (GMM) classifier and a Support Vector Machine (SVM) classifier. Results show that the classifiers were able to achieve 93.11% and 92.67% classification accuracy, respectively, with selected HOS based features. About 2 hours of EEG recordings from 10 patients were used in this study. This thesis introduces unique bispectrum and bicoherence plots for various cardiac conditions and for normal, background and epileptic EEG signals. These plots reveal distinct patterns. The patterns are useful for visual interpretation by those without a deep understanding of spectral analysis such as medical practitioners. It includes original contributions in extracting features from HRV and EEG signals using HOS and entropy, in analyzing the statistical properties of such features on real data and in automated classification using these features with GMM and SVM classifiers.

Striving to realise the European idea : judging the news media’s accounts of how the Berlin Wall gave impetus to a new order across Europe

The 1990 European Community was taken by surprise, by the urgency of demands from the newly-elected Eastern European governments to become member countries. Those governments were honouring the mass social movement of the streets, the year before, demanding free elections and a liberal economic system associated with “Europe”. The mass movement had actually been accompanied by much activity within institutional politics, in Western Europe, the former “satellite” states, the Soviet Union and the United States, to set up new structures – with German reunification and an expanded EC as the centre-piece. This paper draws on the writer’s doctoral dissertation on mass media in the collapse of the Eastern bloc, focused on the Berlin Wall – documenting both public protests and institutional negotiations. For example the writer as a correspondent in Europe from that time, recounts interventions of the German Chancellor, Helmut Kohl, at a European summit in Paris nine days after the “Wall”, and separate negotiations with the French President, Francois Mitterrand -- on the reunification, and EU monetary union after 1992. Through such processes, the “European idea” would receive fresh impetus, though the EU which eventuated, came with many altered expectations. It is argued here that as a result of the shock of 1989, a “social” Europe can be seen emerging, as a shared experience of daily life -- especially among people born during the last two decades of European consolidation. The paper draws on the author’s major research, in four parts: (1) Field observation from the strategic vantage point of a news correspondent. This includes a treatment of evidence at the time, of the wishes and intentions of the mass public (including the unexpected drive to join the European Community), and those of governments, (e.g. thoughts of a “Tienanmen Square solution” in East Berlin, versus the non-intervention policies of the Soviet leader, Mikhail Gorbachev). (2) A review of coverage of the crisis of 1989 by major news media outlets, treated as a history of the process. (3) As a comparison, and a test of accuracy and analysis; a review of conventional histories of the crisis appearing a decade later.(4) A further review, and test, provided by journalists responsible for the coverage of the time, as reflection on practice – obtained from semi-structured interviews.

Designing participation : Reconsidering agile ridesharing with evolutionary distributed design thinking

This paper explores design thinking from the perspective of designing new forms of interaction to engage people in community change initiatives. A case study of an agile ridesharing system is presented. We describe the fundamental premise of the design approach taken—deploying simple interactive prototypes for use by communities in order to test the design hypothesis, evolve the design in use and grow the community of participants. Real-time use data and feedback from participants influences our understanding of the design approach and feeds into the gradual evolution of the prototype while it continues to be used. We then reflect upon this form of evolutionary distributed design thinking. In contrast to the conventional IT wisdom of building systems to automate ride matching and fare calculation using structured forms, our initial phase of design revealed a preference for informal messaging, negotiation and caution in the sharing of specific location information.

Delivering value for money in the procurement of public sector major infrastructure : a new first-order decision making model

The significant challenge faced by government in demonstrating value for money in the delivery of major infrastructure resolves around estimating costs and benefits of alternative modes of procurement. Faced with this challenge, one approach is to focus on a dominant performance outcome visible on the opening day of the asset, as the means to select the procurement approach. In this case, value for money becomes a largely nominal concept and determined by selected procurement mode delivering, or not delivering, the selected performance outcome, and notwithstanding possible under delivery on other desirable performance outcomes, as well as possibly incurring excessive transaction costs. This paper proposes a mind-set change in this particular practice, to an approach in which the analysis commences with the conditions pertaining to the project and proceeds to deploy transaction cost and production cost theory to indicate a procurement approach that can claim superior value for money relative to other competing procurement modes. This approach to delivering value for money in relative terms is developed in a first-order procurement decision making model outlined in this paper. The model developed could be complementary to the Public Sector Comparator (PSC) in terms of cross validation and the model more readily lends itself to public dissemination. As a possible alternative to the PSC, the model could save time and money in preparation of project details to lesser extent than that required in the reference project and may send a stronger signal to the market that may encourage more innovation and competition.