107 resultados para Oscillatory Singular Integrals
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Internet chatrooms are common means of interaction and communications, and they carry valuable information about formal or ad-hoc formation of groups with diverse objectives. This work presents a fully automated surveillance system for data collection and analysis in Internet chatrooms. The system has two components: First, it has an eavesdropping tool which collects statistics on individual (chatter) and chatroom behavior. This data can be used to profile a chatroom and its chatters. Second, it has a computational discovery algorithm based on Singular Value Decomposition (SVD) to locate hidden communities and communication patterns within a chatroom. The eavesdropping tool is used for fine tuning the SVD-based discovery algorithm which can be deployed in real-time and requires no semantic information processing. The evaluation of the system on real data shows that (i) statistical properties of different chatrooms vary significantly, thus profiling is possible, (ii) SVD-based algorithm has up to 70-80% accuracy to discover groups of chatters.
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In this chapter I review the history of copyright in Australia through a singular and exemplary ruling of the Australian High Court made in 2012 and then relate that to the declining fortunes of Australian recorded music professionals. The case in point is Phonographic Performance Company [PPCA] of Australia Limited v Commonwealth of Australia [2012] HCA 8 (hereafter, HCA 8 2012). The case encapsulates the history of copyright law in Australia, with the judicial decision drawing substantive parts of its rationale from the Statute of Anne (8 Anne, c. 19, 1710), as well as copyright acts that regulated the Australian markets prior to 1968. More importantly the High Court decision serves to delineate some important political economic aspects of the recorded music professional in Australia and demonstrates Attali’s (1985) assertion that copyright is the mechanism through which composers are, by statute, literally excluded from capitalistic engagement as ‘productive labour’.
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The classic white formal shirt is a widely and readily familiar object with considerable historical cultural significance to diverse social groups, and is therefore deserving of iconic status. For more than two hundred years, this singular item of apparel has been able to define and represent status, wealth, gender shifts and fashion norms. This garment, which has historically been relinquished to undergarment status, deserves an escalation of standing. The classic white formal shirt, for both men and women, can be used as a mirror to map considerable social change and the diversity of influence can be traced through many examples, including: Beau Brummell’s dandy status with his legendry white shirting; the Gibson Girl with her decorated white shirt style blouse defining ideals of female beauty; IBM business employees in the 1920s marketing trustworthiness through the uniformity of white shirts; the fictional advertising creation of the Arrow Collar Man, with his rigid white shirt, promoting American masculine ideals; and the iconic 1980s Hugo Boss style crisp white dress shirt symbolising power. The origins of the influence of the white shirt can be best traced in the Victorian era where it was an important symbol of wealth and class distinction and a powerful emblem of sobriety and uniformity for men. The pure white colour fulfilled masculine ideals of resolute austerity and the shirt, through its constancy, epitomised conformity and dependability. For women, the white cloth of the ‘shirt-waist’ from this period was also linked to ideals of cleanliness and purity and was seen as an iconic symbol of the new independent working class woman. This paper will propose that the classic white formal shirt, for both men and women, has been a powerful marker of social shifts in Western society and this underrated item of apparel, with limited scholarly writing, is worthy of iconic status. The discussion will trace the historical development of both the men’s and women’s white shirt, each with their own unique history, and in doing so highlight the considerable historical cultural significance associated with the white formal shirt. Discussed first will be the men’s white formal shirt.
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The history of Karen nationalism has been interpreted in terms of inter-ethnic conflict and conceptualizations of ethnicity have influenced understanding of Karen political identity. While 'Karen' incorporated various linguistic, sociocultural, religious and political sub-groups, the Karen National Union (KNU) elite promoted a singular pan-Karen identity in order to minimize such diversity. As a result, factionalism emerged between different Karen groups, obstructing the KNU's political vision and leaving many Karens dissatisfied with KNU attempts to represent their various interests. The fall of Manerplaw in 1995 was thus the result of intra-ethnic conflict as much as conflict between Karens and non-Karens
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Rises recorded for girls’ violence in countries like Australia, Canada, United Kingdom and United States have been hotly contested. One view is these rising rates of violence are an artefact of new forms of policy, policing, criminalisation and social control over young women. Another view is that young women may indeed have become more violent as they have increasingly participated in youth subcultural activities involving gangs and drugs, and cyber‐cultural activities that incite and reward girls’ violence. Any comprehensive explanation will need to address how a complex interplay of cultural, social, behavioural, and policy responses contribute to these rises. This article argues that there is no singular cause, explanation or theory that accounts for the rises in adolescent female violence, and that many of the simple explanations circulating in popular culture are driven by an anti‐feminist ideology. By concentrating on females as victims of violence and very rarely as perpetrators, feminist criminology has for the most part ducked the thorny issue of female violence, leaving a discursive space for anti‐feminist sentiment to reign. The article concludes by arguing the case for developing a feminist theory of female violence.
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The addition of surface tension to the classical Stefan problem for melting a sphere causes the solution to blow up at a finite time before complete melting takes place. This singular behaviour is characterised by the speed of the solid-melt interface and the flux of heat at the interface both becoming unbounded in the blow-up limit. In this paper, we use numerical simulation for a particular energy-conserving one-phase version of the problem to show that kinetic undercooling regularises this blow-up, so that the model with both surface tension and kinetic undercooling has solutions that are regular right up to complete melting. By examining the regime in which the dimensionless kinetic undercooling parameter is small, our results demonstrate how physically realistic solutions to this Stefan problem are consistent with observations of abrupt melting of nanoscaled particles.
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Oscillatory entrainment to the speech signal is important for language processing, but has not yet been studied in developmental disorders of language. Developmental dyslexia, a difficulty in acquiring efficient reading skills linked to difficulties with phonology (the sound structure of language), has been associated with behavioural entrainment deficits. It has been proposed that the phonological ‘deficit’ that characterises dyslexia across languages is related to impaired auditory entrainment to speech at lower frequencies via neuroelectric oscillations (<10 Hz, ‘temporal sampling theory’). Impaired entrainment to temporal modulations at lower frequencies would affect the recovery of the prosodic and syllabic structure of speech. Here we investigated event-related oscillatory EEG activity and contingent negative variation (CNV) to auditory rhythmic tone streams delivered at frequencies within the delta band (2 Hz, 1.5 Hz), relevant to sampling stressed syllables in speech. Given prior behavioural entrainment findings at these rates, we predicted functionally atypical entrainment of delta oscillations in dyslexia. Participants performed a rhythmic expectancy task, detecting occasional white noise targets interspersed with tones occurring regularly at rates of 2 Hz or 1.5 Hz. Both groups showed significant entrainment of delta oscillations to the rhythmic stimulus stream, however the strength of inter-trial delta phase coherence (ITC, ‘phase locking’) and the CNV were both significantly weaker in dyslexics, suggestive of weaker entrainment and less preparatory brain activity. Both ITC strength and CNV amplitude were significantly related to individual differences in language processing and reading. Additionally, the instantaneous phase of prestimulus delta oscillation predicted behavioural responding (response time) for control participants only.
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This paper uses theoretical resources from the sociology of education to consider the teaching of sociology in teacher education programs in Australia. Once a disciplinary ‘pillar’ of teacher education, sociology’s contribution has become less explicit while more integrated, with consequences for disciplinary identity. Here we explore how sociology is taught in teacher education curricula on two fronts. Firstly we outline how sociology is embedded as one of a number of competing perspectives in foundational studies, and its pedagogic consequences. Then we consider the powerful contribution of sociology in literacy studies, amidst public debate about literacy performance. The analysis draws on Bernstein’s (2000) distinction between singular disciplinary curriculum design and practically-oriented regional curriculum design. We seek to trouble the commonsense binary between theory and practice that structures debates around professional education in higher education more broadly, and to dignify service sociology as a valuable, generative site for the discipline’s future.
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Background The management of unruptured aneurysms is controversial with the decision to treat influenced by aneurysm characteristics including size and morphology. Aneurysmal bleb formation is thought to be associated with an increased risk of rupture. Objective To correlate computational fluid dynamic (CFD) indices with bleb formation. Methods Anatomical models were constructed from three-dimensional rotational angiogram (3DRA) data in 27 patients with cerebral aneurysms harbouring single blebs. Additional models representing the aneurysm before bleb formation were constructed by digitally removing the bleb. We characterised haemodynamic features of models both with and without the bleb using CFDs. Flow structure, wall shear stress (WSS), pressure and oscillatory shear index (OSI) were analysed. Results There was a statistically significant association between bleb location at or adjacent to the point of maximal WSS (74.1%, p=0.019), irrespective of rupture status. Aneurysmal blebs were related to the inflow or outflow jet in 88.9% of cases (p<0.001) whilst 11.1% were unrelated. Maximal wall pressure and OSI were not significantly related to bleb location. The bleb region attained a lower WSS following its formation in 96.3% of cases (p<0.001) and was also lower than the average aneurysm WSS in 86% of cases (p<0.001). Conclusion Cerebral aneurysm blebs generally form at or adjacent to the point of maximal WSS and are aligned with major flow structures. Wall pressure and OSI do not contribute to determining bleb location. The measurement of WSS using CFD models may potentially predict bleb formation and thus improve the assessment of rupture risk in unruptured aneurysms.
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This paper merges the analysis of a case history and the simplified theoretical model related to a rather singular phenomenon that may happen in rotating machinery. Starting from the first, a small industrial steam turbine experienced a very strange behavior during megawatt load. When the unit was approaching the maximum allowed power, the temperature of the babbitt metal of the pads of the thrust bearing showed constant increase with an unrecoverable drift. Bearing inspection showed that pad trailing edge had the typical aspect of electrical pitting. This kind of damage was not reparable and bearing pads had to replaced. This problem occurred several times in sequence and was solved only by adding further ground brushes to the shaft-line. Failure analysis indicated electrodischarge machining as the root fault. A specific model, able to take into consideration the effect of electrical pitting and loading capacity decreasing as a consequence of the damage of the babbitt metal, is proposed in the paper and shows that the phenomenon causes the irretrievable failure of the thrust bearing.
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The existence of travelling wave solutions to a haptotaxis dominated model is analysed. A version of this model has been derived in Perumpanani et al. (1999) to describe tumour invasion, where diffusion is neglected as it is assumed to play only a small role in the cell migration. By instead allowing diffusion to be small, we reformulate the model as a singular perturbation problem, which can then be analysed using geometric singular perturbation theory. We prove the existence of three types of physically realistic travelling wave solutions in the case of small diffusion. These solutions reduce to the no diffusion solutions in the singular limit as diffusion as is taken to zero. A fourth travelling wave solution is also shown to exist, but that is physically unrealistic as it has a component with negative cell population. The numerical stability, in particular the wavespeed of the travelling wave solutions is also discussed.
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We study a version of the Keller–Segel model for bacterial chemotaxis, for which exact travelling wave solutions are explicitly known in the zero attractant diffusion limit. Using geometric singular perturbation theory, we construct travelling wave solutions in the small diffusion case that converge to these exact solutions in the singular limit.
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This special issue of the Journal of Learning Design, led by Jill Franz and Lindy Osborne, from the School of Design in the Creative Industries Faculty at the Queensland University of Technology, is grounded in Design Education. Its papers are drawn from differing fields of design: digital media, architecture, and environmental design. Each makes use of technologies in differing ways but all share the singular purpose of achieving enhanced learning outcomes from students.
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An important aspect of decision support systems involves applying sophisticated and flexible statistical models to real datasets and communicating these results to decision makers in interpretable ways. An important class of problem is the modelling of incidence such as fire, disease etc. Models of incidence known as point processes or Cox processes are particularly challenging as they are ‘doubly stochastic’ i.e. obtaining the probability mass function of incidents requires two integrals to be evaluated. Existing approaches to the problem either use simple models that obtain predictions using plug-in point estimates and do not distinguish between Cox processes and density estimation but do use sophisticated 3D visualization for interpretation. Alternatively other work employs sophisticated non-parametric Bayesian Cox process models, but do not use visualization to render interpretable complex spatial temporal forecasts. The contribution here is to fill this gap by inferring predictive distributions of Gaussian-log Cox processes and rendering them using state of the art 3D visualization techniques. This requires performing inference on an approximation of the model on a discretized grid of large scale and adapting an existing spatial-diurnal kernel to the log Gaussian Cox process context.
Jacobian-free Newton-Krylov methods with GPU acceleration for computing nonlinear ship wave patterns
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The nonlinear problem of steady free-surface flow past a submerged source is considered as a case study for three-dimensional ship wave problems. Of particular interest is the distinctive wedge-shaped wave pattern that forms on the surface of the fluid. By reformulating the governing equations with a standard boundary-integral method, we derive a system of nonlinear algebraic equations that enforce a singular integro-differential equation at each midpoint on a two-dimensional mesh. Our contribution is to solve the system of equations with a Jacobian-free Newton-Krylov method together with a banded preconditioner that is carefully constructed with entries taken from the Jacobian of the linearised problem. Further, we are able to utilise graphics processing unit acceleration to significantly increase the grid refinement and decrease the run-time of our solutions in comparison to schemes that are presently employed in the literature. Our approach provides opportunities to explore the nonlinear features of three-dimensional ship wave patterns, such as the shape of steep waves close to their limiting configuration, in a manner that has been possible in the two-dimensional analogue for some time.