2,319 research outputs found

    Nonlinear Robust Control of a Series DC Motor Utilizing the Recursive Design Approach

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    In this thesis, the investigation of asymptotic stability of the series DC motor with unknown load-torque and unknown armature inductance is considered. The control technique of recursive, or backstepping, design is employed. Three cases are considered. In the first case, the system is assumed to be perfectly known. In the second case, the load torque is assumed to be unknown and a proportional-integral controller is developed to compensate for this unknown quantity. In the final case, it is assumed that two system parameters, load torque and armature inductance, are not known exactly, but vary from expected nominal values within a specified range. A robust control is designed to handle this case. The Lyapunov stability criterion is applied in all three cases to prove the stability of the system under the developed control. The results are then verified through the use of computer simulation

    Education for human rights: Opportunities and challenges arising from Australian curriculum reform

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    © Australian Curriculum Studies Association Incorporated 2016. This paper examines the place of human rights education in Australian schools in the light of the National Curriculum’s implementation and unprecedented educational and social/geopolitical change. It also draws on, as part of its literature base, the first nationwide initiative to assess the Australian community’s views on human rights issues by the National Human Rights Consultation Committee (NHRCC, 2009), undertaken by the authors. With global events and technologies challenging previously accepted norms of behaviour, it is vital to consider how school educators can play a more effective role in enabling students to learn about human rights. To support a discussion about the opportunities and challenges facing teachers and students, the paper provides background on the development of a human rights education agenda in Australia. It draws on recent studies that analyse legislation, education policy, curriculum documents, and a set of roundtable consultations. In response to difficult political and community contexts, it is our aim to raise the profile of human rights education and prompt discussion on how to progress it in schools

    Exploring positive adjustment in people with spinal cord injury.

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    This study explored adjustment in people with spinal cord injury; data from four focus groups are presented. Thematic analysis revealed four themes, managing goals and expectations, comparison with others, feeling useful and acceptance, showing participants positively engaged in life, positively interpreted social comparison information and set realistic goals and expectations. These positive strategies show support for adjustment theories, such as the Cognitive Adaptation Theory, the Control Process Theory and Response Shift Theory. These results also provide insight into the adjustment process of a person with spinal cord injury and may be useful in tailoring support during rehabilitation

    Brownian dynamics for the vowel sounds of human language

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    We present a model for the evolution of vowel sounds in human languages, in which words behave as Brownian particles diffusing in acoustic space, interacting via the vowel sounds they contain. Interaction forces, derived from a simple model of the language learning process, are attractive at short range and repulsive at long range. This generates sets of acoustic clusters, each representing a distinct sound, which form patterns with similar statistical properties to real vowel systems. Our formulation may be generalised to account for spontaneous self actuating shifts in system structure which are observed in real languages, and to combine in one model two previously distinct theories of vowel system structure: dispersion theory, which assumes that vowel systems maximize contrasts between sounds, and quantal theory, according to which non linear relationships between articulatory and acoustic parameters are the source of patterns in sound inventories. By formulating the dynamics of vowel sounds using inter-particle forces, we also provide a simple unifi ed description of the linguistic notion of push and pull dynamics in vowel systems.The authors are grateful to the Royal Society for an APEX award (2018-2020), funded by the Leverhulme trust

    Brownian dynamics for the vowel sounds of human language

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    Simulation of the Burridge-Knopoff Model of Earthquakes with Variable Range Stress Transfer

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    Simple models of earthquake faults are important for understanding the mechanisms for their observed behavior, such as Gutenberg-Richter scaling and the relation between large and small events, which is the basis for various forecasting methods. Although cellular automaton models have been studied extensively in the long-range stress transfer limit, this limit has not been studied for the Burridge-Knopoff model, which includes more realistic friction forces and inertia. We find that the latter model with long-range stress transfer exhibits qualitatively different behavior than both the long-range cellular automaton models and the usual Burridge-Knopoff model with nearest neighbor springs, depending on the nature of the velocity-weakening friction force. This result has important implications for our understanding of earthquakes and other driven dissipative systems.Comment: 4 pages, 5 figures, published on Phys. Rev. Let

    Human Rights and History Education: An australian study

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    The place of education for and about human rights within the school curriculum remains contested and this paper reports on the first national crosssectoral investigation of its place in Australian curricula and more specifically in national and state History curriculum documents. Opportunities for the inclusion of human rights based studies were examined across school learning stages, taking into account explicit and implicit, compulsory or elective, as well as curricular and extra-curricular dimensions. Given the continued importance of History as a learning area, there is a need to strengthen the available explicit and mandatory opportunities for students to learn about human rights issues, working closely with key teacher associations, non-government agencies and supportive networks, drawing on available educational technologies

    Relating quanta conservation and compartmental epidemiological models of airborne disease outbreaks in buildings

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    We investigate the underlying assumptions and limits of applicability of several documented models for outbreaks of airborne disease inside buildings by showing how they may each be regarded as special cases of a system of equations which combines quanta conservation and compartmental epidemiological modelling. We investigate the behaviour of this system analytically, gaining insight to its behaviour at large time. We then investigate the characteristic timescales of an indoor outbreak, showing how the dilution rate of the space, and the quanta generation rate, incubation rate and removal rate associated with the illness may be used to predict the evolution of an outbreak over time, and may also be used to predict the relative performances of other indoor airborne outbreak models. The model is compared to a more commonly used model, in which it is assumed the environmental concentration of infectious aerosols adheres to a quasi-steady-state, so that the the dimensionless quanta concentration is equal to the the infectious fraction. The model presented here is shown to approach this limit exponentially to within an interval defined by the incubation and removal rates. This may be used to predict the maximum extent to which a case will deviate from the quasi steady state condition

    Optimal design of adaptively sampled NMR experiments for measurement of methyl group dynamics with application to a ribosome-nascent chain complex

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    NMR measurements of cross-correlated nuclear spin relaxation provide powerful probes of polypeptide dynamics and rotational diffusion, free from contributions due to chemical exchange or interactions with external spins. Here, we report on the development of a sensitivity-optimized pulse sequence for the analysis of the differential relaxation of transitions within isolated 13CH3 spin systems, in order to characterise rotational diffusion and side chain order through the product S2τc. We describe the application of optimal design theory to implement a real-time ‘on-the-fly’ adaptive sampling scheme that maximizes the accuracy of the measured parameters. The increase in sensitivity obtained using this approach enables quantitative measurements of rotational diffusion within folded states of translationally-arrested ribosome–nascent chain complexes of the FLN5 filamin domain, and can be used to place strong limits on interactions between the domain and the ribosome surface
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