Freehand 3D Scanning in a Mobile Environment using Video

This work is motivated by two important trends in consumer computing: (i) the growing pervasiveness of mobile computing devices, and (ii) the users’ desire for increasingly complex but readily acquired and manipulated information content. Specifically, we develop and describe a system for 3D model creation of an object, using only a standard mobile device such as a smart phone. Our approach applies the structured light projection methodology and exploits multiple image input such as frames from a video sequence. In comparison with previous work, a significant further challenge addressed here is that of lower quality input data and limited hardware (processing power and memory, camera and projector quality). Novelties include: (i) a comparison of projection pattern detection approaches in the context of a mobile environment – a robust method combining colour detection and a phase congruency descriptor is evaluated, (ii) a model for single view reconstruction which exploits epipolar, coplanarity and topological constraints, (iii) the use of mobile device sensor data in the iterative closest point algorithm used to register multiple partial 3D reconstructions, and (iv) two heuristics for determining the order in which buffered single view based reconstructions are merged. Our experiments demonstrate that visually appealing results are obtained in a speedy manner which does not require specialist knowledge or expertise from the user.

What a wreck!

Re-enactment of the JC Scammell shipwreck at Point Danger in 1883 : Community Performance written and directed by Wendy Grose with choreography by Jacqui Dreessens and music led by Michele Barnes

Predominant polarity as a course specifier for bipolar disorder: a systematic review

ABSTRACT

David Bowie: dancing with madness and proselytising the socio-political in art and life

A longstanding, successful and frequently controversial career spanning more than four decades establishes David Bowie as charged with individual agency. The notion of ‘agency’ here refers particularly to the ‘ability of people, individually and collectively to influence their own lives and the society in which they live’ (Germov and Poole, 2007: 7). That Bowie has influenced many lives is undeniable to his fans. He has long demonstrated an avid curiosity for the enduring patterns of social life which is reflected in his art. Bowie’s opus contains the elements of ideological narratives around sexual (mis)adventure, expressivity, and; resistance to ‘normative’ behaviour. He requisitions his audiences, through frequently indirect lyrics and images, to critically question sanity, identity and essentially what it means to be ‘us’ and why we are here. Here, in this context, ‘dancing with madness’ assumes an intimate relationship, even if brief, where ideas and emotions come passionately together for the purpose of creative expression much like the intertwining and energetic performance of the partner dance Tango. As such, ‘dancing’ is argued here to be an appropriate descriptor for how Bowie has engaged with creative cultural forms but not meant to be self-conscious nor indicate superficiality or ignorance. The idea of madness for its part is a theme in many of his compositions, for example the original album cover for The Man Who Sold the World (1971)  depicts an asylum and includes the song ‘All The Madmen’ and Aladdin Sane (1973)—a lad insane--are but two examples. This paper argues that Bowie’s frequently astute contemplations, manifest through his art over a period now spanning more than forty years, continues to draw fans of like mind to his work with the result that he has a legitimate claim to influence and affect.

Partial state estimation of LTI systems with multiple constant time-delays

Functional observer design for Multi-Input Multi-Output (MIMO) Linear Time-Invariant (LTI) systems with multiple mixed time delays in the states of the system is addressed. Two structures for the design of a minimum-order observer are considered: 1 - delay-dependent, and 2 - internal-delay independent. The parameters of the delay-dependent observer are designed using the Lyapunov Krasovskii approach. The delay-dependent exponential stability of the observer for a specified convergence rate and delay values is guaranteed upon the feasibility of a set of Linear Matrix Inequalities (LMIs) together with a rank condition. Using the descriptor transformation, a modified Jensen's inequality, and improved Park's inequality, the results can be less conservative than the available functional observer design methods that address LTI systems with single state delay. Furthermore, the necessary and sufficient conditions of the asymptotic stability of the internal-delay independent observer are obtained, which are shown to be independent of delay. Two illustrative numerical examples and simulation studies confirm the validity and highlight the performance of the proposed theoretical achievements.

Responsibility for racism in the everyday talk of secondary students

This article examines the attributions of responsibility for racism in the everyday talk of secondary school students. It draws on focus groups with a cross section of students from different ethnic backgrounds in three, very different, secondary schools. In these focus groups, students deploy six different, sometimes contradictory, racialised discourses. Each discourse attributes responsibility for racism in very different ways that testify to the immanence of the past in the present and students’ positioning in specific social and political conditions. In all but one instance, these discourses work to dismiss, deny and/or deflect responsibility for racism by averting responsibility from the self to other individuals, groups or entities. The empirical data, it is argued, show that the individualisation of responsibility for racism has not seeped its way into students’ race-thinking. This testifies to the persistence of race-thinking, the difficult challenge of finding non-racist ways of being in the world, and cautions against assuming that responsibilisation is a universal descriptor of all contemporary social relations.

Minimum-order filter design for partial state estimation of linear systems with multiple time-varying state delays and unknown input delays

Designing delay-dependent functional observers for LTI systems with multiple known time-varying state delays and unknown time-varying input delays is studied. The input delays are arbitrary, but the state delays should be upper-bounded. In addition, two scenarios of slow-varying and fast-varying state delays are investigated. The results of the paper can also be considered as one of the first contributions considering unknown-input functional observer design for linear systems with multiple time-varying state delays. Based on the Lyapunov Krasovskii approach, delay-dependent sufficient conditions of the exponential stability of the observer in each scenario are established in terms of linear matrix inequalities. Because of using effective techniques, such as the descriptor transformation and an advanced weighted integral inequality, the proposed stability criteria can result in larger stability regions compared with the other papers that study functional observers for time-varying delay systems. Furthermore, to help with the design procedure, a genetic algorithm-based scheme is proposed to adjust a weighting matrix in the established linear matrix inequalities. Two numerical examples illustrate the design procedure and demonstrate the efficacy of the proposed observer in each scenario.

Establishing precise estimates of abundance in patchy habitats of the marine nearshore

Exploratory investigations of optimal sampling designs are a critical component of the decision-making process in ecology where inherent natural variation can lead to erroneous conclusions if left unexamined. Pilot studies and exploratory analyses that investigate the precision of sampling regimes may reduce the chances of erroneous results and can be used to optimise processing time in larger ecological research programs. In our study, we calculated optimal precision estimates for sampling macroinvertebrates and ichthyofauna in surf-zone wrack accumulations by investigating the precision of the mean for sub-samples of seine nets and also for the number of replicate seine nets to guide future sampling regimes. We discovered that the processing time for individual seine net samples could be reduced by 50% using sub-sampling and that time to process replicate seine net samples could be reduced by 25% while maintaining acceptable precision. In future, we suggest that the use of pilot studies with similar exploratory approaches should be less of an exception and more a critical component of ecological investigations, particularly in under-studied or newly-developing areas of research. Further, these types of exploratory approaches are crucially important in a variety of extremely patchy environments where variability is likely to be high.