Non-linear position control for hover and automatic landing of unmanned aerial vehicles

This study presents a disturbance attenuation controller for horizontal position stabilisation for hover and automatic landings of a rotary-wing unmanned aerial vehicle (RUAV) operating close to the landing deck in rough seas. Based on a helicopter model representing aerodynamics during the landing phase, a non-linear state feedback H∞ controller is designed to achieve rapid horizontal position tracking in a gusty environment. Practical constraints including flapping dynamics, servo dynamics and time lag effect are considered. A high-fidelity closed-loop simulation using parameters of the Vario XLC gas-turbine helicopter verifies performance of the proposed horizontal position controller. The proposed controller not only increases the disturbance attenuation capability of the RUAV, but also enables rapid position response when gusts occur. Comparative studies show that the H∞ controller exhibits performance improvement and can be applied to ship/RUAV landing systems.

Reimagining learning spaces : A research report for the Queensland Council for Social Science Innovation

The purpose of the Reimagining Learning Spaces project was to conduct an empirical study that would result in findings to inform the design and use of physical school facilities and examine the ways in which these constructions influence pedagogy. The study focused on newly-established school libraries in Queensland, many of which had been established with funding from the Federal Government’s Building the Education Revolution economic stimulus program. To explore the field, the study sought multiple perspectives that included those of school students as well as teacher-librarians and other key school staff, addressing the following focus question: - How does the physical environment of school libraries influence pedagogic practices and learning outcomes? Further research questions that guided the inquiry included: - What are the implications for teacher-librarians when transitioning into a new library learning space? - How do members of the school community (principals, teachers, teacher-librarians and students) experience the creation of a new school library learning space? - How do school students imagine the design and use of engaging library learning spaces? An extensive review explored Australian and international literature based on the research questions, focused on the following major areas: • School library renewal: trends in reimagining the place of libraries in virtual and real space • School libraries as learning spaces: the expanded role of school libraries in whole-school pedagogical support. • The role of teacher-librarians in new times • Built environments and the implications for learning • Learners and learning in newly established spaces • Learning space design: perspectives, research and principles • Pedagogical principles and voices of experience • Transitions to newly created learning spaces Approach Using an innovative qualitative research design, Reimagining Learning Spaces investigated learner and teacher perspectives across three intersecting domains exploring: - Imagined spaces: learners’ imaginative concepts of learning within engaging learning environments; - Emerging spaces: experiences of teacher-librarians in the transition into new spaces for learning, and - Established spaces: learners’ and teachers’ perceptions of ways in which the physical environment influences and shapes pedagogy. Seven schools that had recently benefitted from the BER program became the research sites at which data were collected from teacher-librarians, teachers, school leaders and students. With this range of participants, an appropriately diverse set of data collection tools was developed, including video interviews, drawings, and focus groups. Evocative narrative case studies (Simons 2009) were developed from the data, representing the voices of users of learning spaces. Key findings The study’s findings are presented in this report and complemented by an array of visual materials on the project web site http:// The report includes: • a set of seven cases studies that reveal nuanced experiences of designing and creating school libraries, based on the narrative of key stakeholders (teacher-librarians, teachers, students and principals) • thematic discussion of student imaginings of their ideal school library, based on drawings and narrative of students at the seven case study schools • critical analysis of the case study and student imaginings, focusing on implications for (re)designing school learning spaces and pedagogy, and responding to the study’s overarching research question - .17 recommendations to support: designing, transitioning and reimagining pedagogy; leadership; and policy development

Public spaces/public disgraces : crowds and the state in contemporary Vietnam

This article argues that a semantic shift in the crowd in Vietnam over the last decade has allowed public space to become a site through which transgressive ideologies and desires may have an outlet. At a time of accelerating social change, the state has effectively delimited public criticism yet a fragile but assertive form of Vietnamese democratic practice has arisen in public space, at the margins of official society, in sites previously equated with state control. Official state functions attract only small audiences, and rather than celebrating the dominance of the party, reveal the disengagement of the populace in the party's activities. Where crowds were always a component of state (stage)-managed events, now public spaces are attracting large numbers of people for supposedly non-political activities which may become transgressive acts condemned by the regime. In support of the notion that crowding is an opening up of the possibility of more subversive political actions, the paper presents an analysis of recent crowd formations and the state's reaction to them. The analysis reveals the modalities through which popular culture has provided the public with the means to transcend the constraints of official, authorized, and legitimate codes of behaviour in public space. Changes in the use of public space, it is argued, map the sets of relations between the public and the state, making these transforming relationships visible, although fraught with contradictions and anomalies.

Reconstructing places and spaces in blended work integrated learning

This paper considers the emergence and ongoing development of an embedded, studentnegotiated work placement model of Work Integrated Learning (WIL) in the engineering and built environment disciplines at an Australian metropolitan university. The characteristics of the model and a continuous improvement strategy are provided. The model is characterised by large student cohorts independently sourcing and negotiating relevant work placements and completing at least one, mandatory credit-bearing WIL unit. Through ongoing analyses and evaluation of the model more experiential and collaborative learning approaches have been adopted. This has included the creation of blended learning spaces using technology. The paper focuses on the five year journey travelled by the teaching team as they embarked on ways to improve curriculum, pedagogy, administrative processes and assessment - effectively relocating much of their interaction with students online. The insights derived from this rich, single case study should be of interest to others considering alternative ways of responding to increasing student enrolments in WIL and the impact of blended learning in this context.

The Australian beachspace : flagging the spaces of Australian beach texts

The Australian beach is a significant component of the Australian culture and a way of life. The Australian Beachspace explores existing research about the Australian beach from a cultural and Australian studies perspective. Initially, the beach in Australian studies has been established within a binary opposition. Fiske, Hodge, and Turner (1987) pioneered the concept of the beach as a mythic space, simultaneously beautiful but abstract. In comparison, Meaghan Morris (1998) suggested that the beach was in fact an ordinary or everyday space. The research intervenes in previous discussions, suggesting that the Australian beach needs to be explored in spatial terms as well as cultural ones. The thesis suggests the beach is more than these previously established binaries and uses Soja's theory of Thirdspace (1996) to posit the term beachspace as a way of describing this complex site. The beachspace is a lived space that encompasses both the mythic and ordinary and more. A variety of texts have been explored in this work, both film and literature. The thesis examines textual representations of the Australian beach using Soja's Thirdspace as a frame to reveal the complexities of the Australian beach through five thematic chapters. Some of the texts discussed include works by Tim Winton's Breath (2008) and Land's Edge (1993), Robert Drewe's short story collections The Bodysurfers (1987) and The Rip (2008), and films such as Newcastle (dir. Dan Castle 2008) and Blackrock (dir. Steve Vidler 1997). Ultimately The Australian Beachspace illustrates that the multiple meanings of the beach's representations are complex and yet frequently fail to capture the layered reality of the Australian beach. The Australian beach is best described as a beachspace, a complex space that allows for the mythic and/or/both ordinary at once.

Hysteretic multilevel NPC converter control for a Switch Mode Assisted Linear Amplifier

A Switch-Mode Assisted Linear Amplifier (SMALA) combines the high quality of a linear amplifier required for audio applications with the high efficiency of a switch-mode amplifier. The careful choice of current sense point and switch placement allows a simple non-isolated hysteresis current controller for the switch-mode section. This paper explains the extension of the hysteresis current controller for the control of a three level Neutral Point Clamped (NPC) converter, with simulations as proof of concept. The NPC topology allows the use of lower voltage switches and lower switching frequencies to implement high power audio amplifiers using the SMALA topology.

Board age and gender diversity : a test of competing linear and curvilinear predictions

The inconsistent findings of past board diversity research demand a test of competing linear and curvilinear diversity–performance predictions. This research focuses on board age and gender diversity, and presents a positive linear prediction based on resource dependence theory, a negative linear prediction based on social identity theory, and an inverted U-shaped curvilinear prediction based on the integration of resource dependence theory with social identity theory. The predictions were tested using archival data on 288 large organizations listed on the Australian Securities Exchange, with a 1-year time lag between diversity (age and gender) and performance (employee productivity and return on assets). The results indicate a positive linear relationship between gender diversity and employee productivity, a negative linear relationship between age diversity and return on assets, and an inverted U-shaped curvilinear relationship between age diversity and return on assets. The findings provide additional evidence on the business case for board gender diversity and refine the business case for board age diversity.

A simplified approach for calculating the moments of action for linear reaction-diffusion equations

The mean action time is the mean of a probability density function that can be interpreted as a critical time, which is a finite estimate of the time taken for the transient solution of a reaction-diffusion equation to effectively reach steady state. For high-variance distributions, the mean action time under-approximates the critical time since it neglects to account for the spread about the mean. We can improve our estimate of the critical time by calculating the higher moments of the probability density function, called the moments of action, which provide additional information regarding the spread about the mean. Existing methods for calculating the nth moment of action require the solution of n nonhomogeneous boundary value problems which can be difficult and tedious to solve exactly. Here we present a simplified approach using Laplace transforms which allows us to calculate the nth moment of action without solving this family of boundary value problems and also without solving for the transient solution of the underlying reaction-diffusion problem. We demonstrate the generality of our method by calculating exact expressions for the moments of action for three problems from the biophysics literature. While the first problem we consider can be solved using existing methods, the second problem, which is readily solved using our approach, is intractable using previous techniques. The third problem illustrates how the Laplace transform approach can be used to study coupled linear reaction-diffusion equations.

Peer review of teaching practice and resources : exploring new spaces to embrace cultural change

The implementation of systematic peer review as a professional development activity, and as a support for educational design activities is under-utilised in many Australian higher education institutions. This case study reports on the first stages of planning and implementation of an institution-wide project to enhance teaching and learning quality at a remote and regional university, where one of the major strategies for improvement is peer review. Through a systematic process of staff engagement in peer review, within and from outside the organisation, a substantial change in flexible learning is envisaged. A mix of new and different learning spaces are to be used in the project, including blended learning spaces for academic development. This paper describes the research framework that will guide the peer review process and examines the early findings of the design-based research. Leadership, awareness raising and development of a supportive community of inquiry are seen as key components for successful implementation of peer review. In addition, unique contextual elements add to the complexity of designing for transformative change within such a relatively new organization.

Block models for improved earthwork allocation planning in linear infrastructure construction

Earthwork planning has been considered in this article and a generic block partitioning and modelling approach has been devised to provide strategic plans of various levels of detail. Conceptually this approach is more accurate and comprehensive than others, for instance those that are section based. In response to environmental concerns the metric for decision making was fuel consumption and emissions. Haulage distance and gradient are also included as they are important components of these metrics. Advantageously the fuel consumption metric is generic and captures the physical difficulties of travelling over inclines of different gradients, that is consistent across all hauling vehicles. For validation, the proposed models and techniques have been applied to a real world road project. The numerical investigations have demonstrated that the models can be solved with relatively little CPU time. The proposed block models also result in solutions of superior quality, i.e. they have reduced fuel consumption and cost. Furthermore the plans differ considerably from those based solely upon a distance based metric thus demonstrating a need for industry to reflect upon their current practices.

Improving public spaces for young people : the contribution of participatory research

The objectives of this chapter are to examine the contribution of public spaces to the wellbeing of young people and how participatory action research can be used as a process tool for contextually responsive, collaborative, iterative and multi-method community level practice. The addition of a spatial frame to practice can open up unexpected alliances and opportunities for enhancing the wellbeing of people.

Higher-order non-linear analysis of steel structures. Part I : elastic second-order formulation

This paper presents a higher-order beam-column formulation that can capture the geometrically non-linear behaviour of steel framed structures which contain a multiplicity of slender members. Despite advances in computational frame software, analyses of large frames can still be problematic from a numerical standpoint and so the intent of the paper is to fulfil a need for versatile, reliable and efficient non-linear analysis of general steel framed structures with very many members. Following a comprehensive review of numerical frame analysis techniques, a fourth-order element is derived and implemented in an updated Lagrangian formulation, and it is able to predict flexural buckling, snap-through buckling and large displacement post-buckling behaviour of typical structures whose responses have been reported by independent researchers. The solutions are shown to be efficacious in terms of a balance of accuracy and computational expediency. The higher-order element forms a basis for augmenting the geometrically non-linear approach with material non-linearity through the refined plastic hinge methodology described in the companion paper.

Higher-order non-linear analysis of steel structures. Part II : refined plastic hinge formulation

In the companion paper, a fourth-order element formulation in an updated Lagrangian formulation was presented to handle geometric non-linearities. The formulation of the present paper extends this to include material non-linearity by proposing a refined plastic hinge approach to analyse large steel framed structures with many members, for which contemporary algorithms based on the plastic zone approach can be problematic computationally. This concept is an advancement of conventional plastic hinge approaches, as the refined plastic hinge technique allows for gradual yielding, being recognized as distributed plasticity across the element section, a condition of full plasticity, as well as including strain hardening. It is founded on interaction yield surfaces specified analytically in terms of force resultants, and achieves accurate and rapid convergence for large frames for which geometric and material non-linearity are significant. The solutions are shown to be efficacious in terms of a balance of accuracy and computational expediency. In addition to the numerical efficiency, the present versatile approach is able to capture different kinds of material and geometric non-linearities on general applications of steel structures, and thereby it offers an efficacious and accurate means of assessing non-linear behaviour of the structures for engineering practice.

Capturing complex, non-linear team behaviours during competitive football performance

This study investigated changes in the complexity (magnitude and structure of variability) of the collective behaviours of association football teams during competitive performance. Raw positional data from an entire competitive match between two professional teams were obtained with the ProZone® tracking system. Five compound positional variables were used to investigate the collective patterns of performance of each team including: surface area, stretch index, team length, team width, and geometrical centre. Analyses involve the coefficient of variation (%CV) and approximate entropy (ApEn), as well as the linear association between both parameters. Collective measures successfully captured the idiosyncratic behaviours of each team and their variations across the six time periods of the match. Key events such as goals scored and game breaks (such as half time and full time) seemed to influence the collective patterns of performance. While ApEn values significantly decreased during each half, the %CV increased. Teams seem to become more regular and predictable, but with increased magnitudes of variation in their organisational shape over the natural course of a match.

Comparison of high level FPGA hardware design for solving tri-diagonal linear systems

Reconfigurable computing devices can increase the performance of compute intensive algorithms by implementing application specific co-processor architectures. The power cost for this performance gain is often an order of magnitude less than that of modern CPUs and GPUs. Exploiting the potential of reconfigurable devices such as Field-Programmable Gate Arrays (FPGAs) is typically a complex and tedious hardware engineering task. Re- cently the major FPGA vendors (Altera, and Xilinx) have released their own high-level design tools, which have great potential for rapid development of FPGA based custom accelerators. In this paper, we will evaluate Altera’s OpenCL Software Development Kit, and Xilinx’s Vivado High Level Sythesis tool. These tools will be compared for their per- formance, logic utilisation, and ease of development for the test case of a Tri-diagonal linear system solver.