833 resultados para Work processes
Resumo:
'If we do not cut social spending, we will end up like Greece'. Establishment politicians and media figures use this new ideological mantra throughout the Western world to frighten people into consenting to further neo-liberal restructuring along with cuts in social spending. This phrase and other ideologically laden assertions hide the real causes of the Greek public debt crisis. This commentary challenges the dominant discourse by contextualizing the Greek case within the larger global neo-liberal restructuring processes and then, drawing upon Gramsci's concept of the organic intellectual, proposes ways that the members of the Professional Association of Social Workers (PASW) can engage in a war of ideas and action, as organic intellectuals, to delegitimize the dominant discourse, which seeks consent for social spending cuts and further neo-liberal restructuring of society. © The Author(s) 2013.
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The aim of this paper is to develop a new generation of extruder control system for recycled materials which has ability to automatically maintain constant a polymer melt viscosity of mixed recycled polymers during extrusion, regardless of variations in the Melt Flow Index (MFI) of recycled mixed grade high density polyethylene (HDPE) feedstock. The variations in MFI are due to differences in the source of the recycled material used. The work describes how melt viscosity for specific extruder/die system is calculated in real time using the rheological properties of the materials, the pressure drop through the extruder die and the actual throughput measurements using a gravimetric loss-in-weight hopper feeder. A closed-loop controller is also developed to automatically regulate screw speed and barrel temperature profile to achieve constant viscosity and enable consistent processing of variable grade recycled HDPE materials. Such a system will improve processability of mixed MFI polymers may also reduce the risk of polymer melt degradation, reduce producing large volumes of scrap/waste and lead to improvement in product quality. The experimental results of real time viscosity measurement and control using a 38 mm single screw extruder with different recycled HDPEs with widely different MFIs are reported in this work.
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Semiconductor fabrication involves several sequential processing steps with the result that critical production variables are often affected by a superposition of affects over multiple steps. In this paper a Virtual Metrology (VM) system for early stage measurement of such variables is presented; the VM system seeks to express the contribution to the output variability that is due to a defined observable part of the production line. The outputs of the processed system may be used for process monitoring and control purposes. A second contribution of this work is the introduction of Elastic Nets, a regularization and variable selection technique for the modelling of highly-correlated datasets, as a technique for the development of VM models. Elastic Nets and the proposed VM system are illustrated using real data from a multi-stage etch process used in the fabrication of disk drive read/write heads. © 2013 IEEE.
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In the semiconductor manufacturing environment it is very important to understand which factors have the most impact on process outcomes and to control them accordingly. This is usually achieved through design of experiments at process start-up and long term observation of production. As such it relies heavily on the expertise of the process engineer. In this work, we present an automatic approach to extracting useful insights about production processes and equipment based on state-of-the-art Machine Learning techniques. The main goal of this activity is to provide tools to process engineers to accelerate the learning-by-observation phase of process analysis. Using a Metal Deposition process as an example, we highlight various ways in which the extracted information can be employed.
Resumo:
The aim of this paper is to develop a new extruder control system for recycled materials which has ability to automatically maintain constant a polymer melt viscosity of mixed recycled polymers during extrusion, regardless of variations in the Melt Flow Index (MFI) of recycled mixed grade high density polyethylene (HDPE) feedstock. A closed-loop controller is developed to automatically regulate screw speed and barrel temperature profile to achieve constant viscosity and enable consistent processing of variable grade recycled HDPE materials. The experimental results of real time viscosity measurement and control using a 38mm single screw extruder with different recycled HDPEs with widely different MFIs are reported in this work
Resumo:
Health reform practices in Canada and elsewhere have restructured the purpose and use of diagnostic labels and the processes of naming such labels. Diagnoses are no longer only a means to tell doctors and patients what may be wrong and indicate potential courses of treatment; some diagnoses activate specialized services and supports for persons with a disability and those who provide care for them. In British Columbia, a standardized process of diagnosis with the outcome of an autism spectrum disorder gives access to government provided health care and educational services and supports. Such processes enter individuals into a complex of text mediated relations, regulated by the principles of evidence-based medicine. However, the diagnosis of autism in children is notoriously uncertain. Because of this ambiguity, standardizing the diagnostic process creates a hurdle in gaining help and support for parents who have children with problems that could lead to a diagnosis on the autism spectrum. Such processes and their organizing relations are problematized, explored and explicated below. Grounded in the epistemological and ontological shift offered by Dorothy E. Smith (1987; 1990a; 1999; 2005), this article reports on the findings of an institutional ethnographic study that explored the diagnostic process of autism in British Columbia. More specifically, this article focuses on the processes involved in going from mothers talking from their experience about their childrens problems to the formalized and standardized, and thus “virtually” produced, diagnoses that may or may not give access to services and supports in different systems of care. Two psychologists, a developmental pediatrician, a social worker – members of a specialized multidisciplinary assessment team – and several mothers of children with a diagnosis on the autism spectrum were interviewed. The implications of standardizing the diagnosis process of a disability that is not clear-cut and has funding attached are discussed. This ethnography also provides a glimpse of the implications of current and ongoing reforms in the state-supported health care system in British Columbia, and more generally in Canada, for people’s everyday doings.
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Nas últimas décadas, um grande número de processos têm sido descritos em termos de redes complexas. A teoria de redes complexas vem sendo utilizada com sucesso para descrever, modelar e caracterizar sistemas naturais, artificias e sociais, tais como ecossistemas, interações entre proteínas, a Internet, WWW, até mesmo as relações interpessoais na sociedade. Nesta tese de doutoramento apresentamos alguns modelos de agentes interagentes em redes complexas. Inicialmente, apresentamos uma breve introdução histórica (Capítulo 1), seguida de algumas noções básicas sobre redes complexas (Capítulo 2) e de alguns trabalhos e modelos mais relevantes a esta tese de doutoramento (Capítulo 3). Apresentamos, no Capítulo 4, o estudo de um modelo de dinâmica de opiniões, onde busca-se o consenso entre os agentes em uma população, seguido do estudo da evolução de agentes interagentes em um processo de ramificação espacialmente definido (Capítulo 5). No Capítulo 6 apresentamos um modelo de otimização de fluxos em rede e um estudo do surgimento de redes livres de escala a partir de um processo de otimização . Finalmente, no Capítulo 7, apresentamos nossas conclusões e perspectivas futuras.
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The work presented in this Ph.D thesis was developed in the context of complex network theory, from a statistical physics standpoint. We examine two distinct problems in this research field, taking a special interest in their respective critical properties. In both cases, the emergence of criticality is driven by a local optimization dynamics. Firstly, a recently introduced class of percolation problems that attracted a significant amount of attention from the scientific community, and was quickly followed up by an abundance of other works. Percolation transitions were believed to be continuous, until, recently, an 'explosive' percolation problem was reported to undergo a discontinuous transition, in [93]. The system's evolution is driven by a metropolis-like algorithm, apparently producing a discontinuous jump on the giant component's size at the percolation threshold. This finding was subsequently supported by number of other experimental studies [96, 97, 98, 99, 100, 101]. However, in [1] we have proved that the explosive percolation transition is actually continuous. The discontinuity which was observed in the evolution of the giant component's relative size is explained by the unusual smallness of the corresponding critical exponent, combined with the finiteness of the systems considered in experiments. Therefore, the size of the jump vanishes as the system's size goes to infinity. Additionally, we provide the complete theoretical description of the critical properties for a generalized version of the explosive percolation model [2], as well as a method [3] for a precise calculation of percolation's critical properties from numerical data (useful when exact results are not available). Secondly, we study a network flow optimization model, where the dynamics consists of consecutive mergings and splittings of currents flowing in the network. The current conservation constraint does not impose any particular criterion for the split of current among channels outgoing nodes, allowing us to introduce an asymmetrical rule, observed in several real systems. We solved analytically the dynamic equations describing this model in the high and low current regimes. The solutions found are compared with numerical results, for the two regimes, showing an excellent agreement. Surprisingly, in the low current regime, this model exhibits some features usually associated with continuous phase transitions.
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The Asymmetric Power Arch representation for the volatility was introduced by Ding et al.(1993) in order to account for asymmetric responses in the volatility in the analysis of continuous-valued financial time series like, for instance, the log-return series of foreign exchange rates, stock indices or share prices. As reported by Brannas and Quoreshi (2010), asymmetric responses in volatility are also observed in time series of counts such as the number of intra-day transactions in stocks. In this work, an asymmetric power autoregressive conditional Poisson model is introduced for the analysis of time series of counts exhibiting asymmetric overdispersion. Basic probabilistic and statistical properties are summarized and parameter estimation is discussed. A simulation study is presented to illustrate the proposed model. Finally, an empirical application to a set of data concerning the daily number of stock transactions is also presented to attest for its practical applicability in data analysis.
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The paper focuses on emotions and processes that may arise for practice educators when working with a struggling or failing student in a practice learning setting.1 The paper firstly documents a previously undertaken thematic review of the literature, which explored why practice educators appeared to find it difficult to fail students in practice learning settings. Secondly, the paper draws on two UK qualitative studies that highlighted the emotional distress experienced by practice educators when working with a marginal or failing student. The paper documents key findings using a case study approach from both studies. We argue that the concept of projective identification offers a plausible and illuminating account of the states of mind experienced by practice educators and in making explicit, unconscious states of mind, our aim is that practice educators will feel confident to make appropriate assessment decisions when required.
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The paper centres on a single document, the 1968 doctoral thesis of L Bruce Archer. It traces the author’s earlier publications and the sources that informed and inspired his thinking, as a way of understanding the trajectory of his ideas and the motivations for his work at the Royal College of Art from 1962. Analysis of the thesis suggests that Archer’s ambition for a rigorous ‘science of design’ inspired by algorithmic approaches was increasingly threatened with disruption by his experience of large, complex design projects. His attempts to deal with this problem are shown to involve a particular interpretation of cybernetics. The paper ends with Archer’s own retrospective view and a brief account of his dramatically changed opinions. Archer is located as both a theorist and someone intensely interested in the commercial world of industrial design.
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Tese de doutoramento, Farmácia (Tecnologia Farmacêutica), Universidade de Lisboa, Faculdade de Farmácia, 2014
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Successful participation in competitive endurance activities requires continual regulation of muscular work rate in order to maximise physiological performance capacities, meaning that individuals must make numerous decisions with regards to the muscular work rate selected at any point in time. Decisions relating to the setting of appropriate goals and the overall strategic approach to be utilised are made prior to the commencement of an event, whereas tactical decisions are made during the event itself. This review examines current theories of decision-making in an attempt to explain the manner in which regulation of muscular work is achieved during athletic activity. We describe rational and heuristic theories, and relate these to current models of regulatory processes during self-paced exercise in an attempt to explain observations made in both laboratory and competitive environments. Additionally, we use rational and heuristic theories in an attempt to explain the influence of the presence of direct competitors on the quality of the decisions made during these activities. We hypothesise that although both rational and heuristic models can plausibly explain many observed behaviours in competitive endurance activities, the complexity of the environment in which such activities occur would imply that effective rational decision-making is unlikely. However, at present, many proposed models of the regulatory process share similarities with rational models. We suggest enhanced understanding of the decision-making process during self-paced activities is crucial in order to improve the ability to understand regulation of performance and performance outcomes during athletic activity.
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Soil vapor extraction (SVE) is an efficient, well-known and widely applied soil remediation technology. However, under certain conditions it cannot achieve the defined cleanup goals, requiring further treatment, for example, through bioremediation (BR). The sequential application of these technologies is presented as a valid option but is not yet entirely studied. This work presents the study of the remediation of ethylbenzene (EB)-contaminated soils, with different soil water and natural organic matter (NOMC) contents, using sequential SVE and BR. The obtained results allow the conclusion that: (1) SVE was sufficient to reach the cleanup goals in 63% of the experiments (all the soils with NOMC below 4%), (2) higher NOMCs led to longer SVE remediation times, (3) BR showed to be a possible and cost-effective option when EB concentrations were lower than 335 mg kgsoil −1, and (4) concentrations of EB above 438 mg kgsoil −1 showed to be inhibitory for microbial activity.