944 resultados para Iterative methods (Mathematics)
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Background: This paper describes research conducted with Big hART, Australia's most awarded participatory arts company. It considers three projects, LUCKY, GOLD and NGAPARTJI NGAPARTJI across separate sites in Tasmania, Western NSW and Northern Territory, respectively, in order to understand project impact from the perspective of project participants, Arts workers, community members and funders. Methods: Semi-structured interviews were conducted with 29 respondents. The data were coded thematically and analysed using the constant comparative method of qualitative data analysis. Results: Seven broad domains of change were identified: psychosocial health; community; agency and behavioural change; the Art; economic effect; learning and identity. Conclusions: Experiences of participatory arts are interrelated in an ecology of practice that is iterative, relational, developmental, temporal and contextually bound. This means that questions of impact are contingent, and there is no one path that participants travel or single measure that can adequately capture the richness and diversity of experience. Consequently, it is the productive tensions between the domains of change that are important and the way they are animated through Arts practice that provides sign posts towards the impact of Big hART projects.
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In late 2011, first year university students in science, technology, engineering and mathematics (STEM) courses across Australia were invited to participate in the international Interests and Recruitment in Science (IRIS) study. IRIS investigates the influences on young people's decisions to choose university STEM courses and their subsequent experiences of these courses. The study also has a particular focus on the motivations and experiences of young women in courses such as physics, IT and engineering given the low rates of female participation in these fields. Around 3500 students from 30 Australian universities contributed their views on the relative importance of various school and non-school influences on their decisions, as well as insights into their experiences of university STEM courses so far. It is hoped that their contributions will help improve recruitment, retention and gender equity in STEM higher education and careers.
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The safe working lifetime of a structure in a corrosive or other harsh environment is frequently not limited by the material itself but rather by the integrity of the coating material. Advanced surface coatings are usually crosslinked organic polymers such as epoxies and polyurethanes which must not shrink, crack or degrade when exposed to environmental extremes. While standard test methods for environmental durability of coatings have been devised, the tests are structured more towards determining the end of life rather than in anticipation of degradation. We have been developing prognostic tools to anticipate coating failure by using a fundamental understanding of their degradation behaviour which, depending on the polymer structure, is mediated through hydrolytic or oxidation processes. Fourier transform infrared spectroscopy (FTIR) is a widely-used laboratory technique for the analysis of polymer degradation and with the development of portable FTIR spectrometers, new opportunities have arisen to measure polymer degradation non-destructively in the field. For IR reflectance sampling, both diffuse (scattered) and specular (direct) reflections can occur. The complexity in these spectra has provided interesting opportunities to study surface chemical and physical changes during paint curing, service abrasion and weathering, but has often required the use of advanced statistical analysis methods such as chemometrics to discern these changes. Results from our studies using this and related techniques and the technical challenges that have arisen will be presented.
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Modern lipidomics relies heavily on mass spectrometry for the structural characterization and quantification of lipids of biological origins. Structural information is gained by tandem mass spectrometry (MS/MS) whereby lipid ions are fragmented to elucidate lipid class, fatty acid chain length, and degree of unsaturation. Unfortunately, however, in most cases double bond position cannot be assigned based on MS/MS data alone and thus significant structural diversity is hidden from such analyses. For this reason, we have developed two online methods for determining double bond position within unsaturated lipids; ozone electrospray ionization mass spectrometry (OzESI-MS) and ozone-induced dissociation (OzID). Both techniques utilize ozone to cleave C-C double bonds that result in chemically induced fragment ions that locate the position(s) of unsaturation
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Iterative Intersectioning is a body of art works that comes out of the collaboration between author and electronic artist Jen Seevinck and a community of print artists, most particularly Elizabeth Saunders (EJ) and Robert Oakman. The work shown here is concerned with the creative process of collaboration, specifically as this informs visual forms. This is through our focus on process. This process has facilitated a 'conversational' exchange between all artists and a corresponding evolution in the artworks. In each case the dialogue is either between the author, Jen and EJ or between Jen and Robert. It consists of passing work between parties, interpreting it and working into it, before passing it back. The result is a series of art works including those shown here. The concept evolves in parallel to this. Importantly, at each of her iterations of creative work, the author Jen determines a similar 'treatment' or 'interpretation' across both print artists works at that time. A synthesis of EJ and Robert's creative interpretation -- at a high level -- occurs. In this sense the concept and works can be understood to intersect with one another.
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.
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Samples of sea water contain phytoplankton taxa in varying amounts, and marine scientists are interested in the relative abundance of each taxa. Their relative biomass can be ascertained indirectly by measuring the quantity of various pigments using high performance liquid chromatography. However, the conversion from pigment to taxa is mathematically non trivial as it is a positive matrix factorisation problem where both matrices are unknown beyond the level of initial estimates. The prior information on the pigment to taxa conversion matrix is used to give the problem a unique solution. An iteration of two non-negative least squares algorithms gives satisfactory results. Some sample analysis of data indicates prospects for this type of analysis. An alternative more computationally intensive approach using Bayesian methods is discussed.
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Dose-finding trials are a form of clinical data collection process in which the primary objective is to estimate an optimum dose of an investigational new drug when given to a patient. This thesis develops and explores three novel dose-finding design methodologies. All design methodologies presented in this thesis are pragmatic. They use statistical models, incorporate clinicians' prior knowledge efficiently, and prematurely stop a trial for safety or futility reasons. Designing actual dose-finding trials using these methodologies will minimize practical difficulties, improve efficiency of dose estimation, be flexible to stop early and reduce possible patient discomfort or harm.
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A control allocation system implements a function that maps the desired control forces generated by the vehicle motion controller into the commands of the different actuators. In this article, a survey of control allocation methods for over-actuated underwater vehicles is presented. The methods are applicable for both surface vessels and underwater vehicles. The paper presents a survey of control allocation methods with focus on mathematical representation and solvability of thruster allocation problems. The paper is useful for university students and engineers who want to get an overview of state-of-the art control allocation methods as well as advance methods to solve more complex problems.
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"The authors agree with the statements made by Mills and Christy on the study of kapundaite [1]. These authors are correct and have removed any confusion about the origin of the sample kapundaite. The authors (Frost et al.) confirm the sample of kapundaite studied in this work is from the Tom‘s quarry, Australia and can be considered a type material. The authors do not accept the statements by Mills and Christy on “type minerals”. The sample of kapundaite from the Australian source is from the collection of the Geology Department of the Federal University of Ouro Preto, Minas Gerais, Brazil with sample code SAC-111. At least if our mineral sample is not a co-type mineral, our sample is from the same origin as the type mineral. Samples..."--publisher website.
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Objectives: To examine factors associated with the uptake of i) long-acting reversible, ii) permanent and iii) traditional contraceptive methods among Australian women. Methods: Participants in the Australian Longitudinal Study on Women's Health born in 1973–78 reported on their contraceptive use at three surveys: 2003, 2006 and 2009. The participants were 5,849 women aged 25–30 in 2003 randomly sampled from Medicare. The main outcome measure was current contraceptive method at age 28–33 years categorised as long-acting reversible methods (implant, IUD, injection), permanent (tubal ligation, vasectomy), and traditional methods (oral contraceptive pills, condoms, withdrawal, safe period). Results: Compared to women living in major cities, women in inner regional areas were more likely to use long-acting (OR=1.26, 95%CI 1.03–1.55) or permanent methods (OR=1.43, 95%CI 1.17–1.76). Women living in outer regional/remote areas were more likely than women living in cities to use long-acting (OR=1.65, 95%CI 1.31–2.08) or permanent methods (OR=1.69, 95%CI 1.43–2.14). Conclusions: Location of residence is an important factor in women's choices about long-acting and permanent contraception in addition to the number and age of their children. Implications: Further research is needed to understand the role of geographical location in women's access to contraceptive options in Australia.
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This paper reports on a four year Australian Research Council funded Linkage Project titled Skilling Indigenous Queensland, conducted in regional areas of Queensland, Australia from 2009 to 2013. The project sought to investigate Vocational Education and Training (VET) and teaching, Indigenous learners’ needs, employer culture and expectations and community culture and expectations to identify best practice in numeracy teaching for Indigenous VET learners. Specifically it focused on ways to enhance the teaching and learning of courses and the associated mathematics in such courses to benefit learners and increase their future opportunities of employment. To date thirty - nine teachers/trainers/teacher aides and two hundred and thirty - one students consented to participate in the project. Nine VET courses offered in schools and Technical and Further Education Institutes (TAFE) were nominated to be the focus on the study. This paper focuses on student questionnaire responses and interview responses from teachers/trainers one high school principal and five students as a result of these processes, the findings indicated that VET course teachers work hard to adopt contextualising strategies to their teaching; however this process is not always straight forward because of the perceptions of how mathematics has been taught and learned by trainers and teachers. Further teachers, trainers and students have high expectations of one another with the view to successful outcomes from the courses.
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Studies on quantitative fit analysis of precontoured fracture fixation plates emerged within the last few years and therefore, there is a wide research gap in this area. Quantitative fit assessment facilitates the measure of the gap between a fracture fixation plate and the underlying bone, and specifies the required plate fit criteria. For clinically meaningful fit assessment outcome, it is necessary to establish the appropriate criteria and parameter. The present paper studies this subject and recommends using multiple fit criteria and the maximum distance between the plate and underlying bone as fit parameter for clinically relevant outcome. We also propose the development of a software tool for automatic plate positioning and fit assessment for the purpose of implant design validation and optimization in an effort to provide better fitting implant that can assist proper fracture healing. The fundamental specifications of the software are discussed.
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Organizations invest in ways to stimulate new ideas for new products and services for the benefit of the organization, engaging in tournaments and competitions to generate new ideas or to combine existing ideas in new ways for new products and services (Terweisch and Uhlrich, 2009). Specifically, some large companies have developed platforms for posting intractable problems to tap into the ideas and problem solving abilities of a broader range of people (Huston and Sakkab, 2006; Morgan and Wang, 2010), and to develop new and elegant solutions often in an open innovation approach (Chesbrough, 2003). The notion of ingenuity is often applied to individuals who create innovative solutions in situations of constraint, where ingenuity in the form of elegant solutions can be understood as one form of resourcefulness (Young, 2011). However, the notion of organizational ingenuity locates ingenuity more centrally to an organization's strategic decision making and implementation, embedding ingenuity into the company's culture. Studies of organizations displaying ingenuity indicate a range of possibilities from extreme ingenuity (Baker and Nelson, 2005) to less dramatic but substantial changes (Thomke, 2003), sometimes in an experimental phase or as part of a move towards a new and distinct identity for ongoing innovation.