509 resultados para Feeder reconfigurations


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Os contornos de um mundo em mudança e a evolução do pensamento há muito que se afastaram dos conceitos de identidades unas e imutáveis. A própria aceitação da mutabilidade traduz-se também nos cenários das vastas possibilidades para os fenómenos identitários à escala global. Também por isso, e mais do que nunca, se revela preponderante a reflexão sobre tais fenómenos identitários e a compreensão da sua intervenção e pertinência nas constantes reconfigurações sociais da atualidade. Esse será o universo do presente trabalho, onde serão auscultadas atuais conceções identitárias e o seu lugar no caso português. Este estudo configura-se, portanto, a partir de objetivos centrais bem delimitados: identificar e caracterizar a eventual existência de identidades regionais em Portugal, no caso particular dos territórios associados a Viseu. Este ponto de partida surge da análise da frequente cartografia das identidades territoriais na realidade portuguesa, bem como da continuidade de anteriores estudos do autor. Com efeito, verifica-se que frequentemente se definem duas grandes tipologias identitárias no que concerne à relação com o território: a local e a nacional. Tal posição surge em aberta contradição com os discursos mediáticos recorrentes onde a constante presença de um discurso de matriz regional obriga à dúvida inevitável. Nesse sentido, falando-se de região, foi necessário percorrer os conceitos de limite e de fronteira que a delimitam e lhe conferem sentido, indagando-se sobre o lugar da sua criação e da sua vivência. Assim, o trabalho orientou-se em dois grandes sentidos iniciais: o do levantamento da ação delimitadora do Estado, tido como autor das demarcações regionais em Portugal e o da auscultação da produção discursiva dos media regionais, agentes e expressão da identidade regional. A segunda dimensão obrigaria a um estudo aturado sobre a imprensa regional, objeto essencial do presente trabalho e a partir do qual será possível alcançar conclusões validáveis para o período entre 1959 e 2011. É então pelo cruzamento das duas dimensões referidas que se surpreende a existência de traços identitários regionais bem vincados, profundamente arreigados ao discurso do Estado Novo, raramente correspondendo aos intentos de delimitação das sucessivas iniciativas governamentais posteriores que, desse modo, revelam também um profundo distanciamento desse território que insistentemente vão dividindo. Entre o discurso eivado de simbolismo – embora centralista – do Estado Novo e as denominações técnicas – embora com o propósito de promover a descentralização do poder – da democracia, o discurso identitário da imprensa regional de Viseu alimenta-se ainda hoje do primeiro. Não porque vise os seus objetivos, mas porque é o que melhor caracteriza uma identidade relativamente pacificada: sempre pronta a recorrer ao passado beirão para afirmar as suas diferenças, sem no entanto pôr em causa o espírito da Nação; sempre pronta a denunciar o centralismo de Lisboa, esquecendo embora que foi esse centralismo que outrora lhe atribuiu a característica da genuinidade de, o que quer que seja, ser português.

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Dynamically reconfigurable hardware is a promising technology that combines in the same device both the high performance and the flexibility that many recent applications demand. However, one of its main drawbacks is the reconfiguration overhead, which involves important delays in the task execution, usually in the order of hundreds of milliseconds, as well as high energy consumption. One of the most powerful ways to tackle this problem is configuration reuse, since reusing a task does not involve any reconfiguration overhead. In this paper we propose a configuration replacement policy for reconfigurable systems that maximizes task reuse in highly dynamic environments. We have integrated this policy in an external taskgraph execution manager that applies task prefetch by loading and executing the tasks as soon as possible (ASAP). However, we have also modified this ASAP technique in order to make the replacements more flexible, by taking into account the mobility of the tasks and delaying some of the reconfigurations. In addition, this replacement policy is a hybrid design-time/run-time approach, which performs the bulk of the computations at design time in order to save run-time computations. Our results illustrate that the proposed strategy outperforms other state-ofthe-art replacement policies in terms of reuse rates and achieves near-optimal reconfiguration overhead reductions. In addition, by performing the bulk of the computations at design time, we reduce the execution time of the replacement technique by 10 times with respect to an equivalent purely run-time one.

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Reconfigurable HW can be used to build a hardware multitasking system where tasks can be assigned to the reconfigurable HW at run-time according to the requirements of the running applications. Normally the execution in this kind of systems is controlled by an embedded processor. In these systems tasks are frequently represented as subtask graphs, where a subtask is the basic scheduling unit that can be assigned to a reconfigurable HW. In order to control the execution of these tasks, the processor must manage at run-time complex data structures, like graphs or linked list, which may generate significant execution-time penalties. In addition, HW/SW communications are frequently a system bottleneck. Hence, it is very interesting to find a way to reduce the run-time SW computations and the HW/SW communications. To this end we have developed a HW execution manager that controls the execution of subtask graphs over a set of reconfigurable units. This manager receives as input a subtask graph coupled to a subtask schedule, and guarantees its proper execution. In addition it includes support to reduce the execution-time overhead due to reconfigurations. With this HW support the execution of task graphs can be managed efficiently generating only very small run-time penalties.

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The demand for alternative sources of energy drives the technological development so that many fuels and energy conversion processes before judged as inadequate or even non-viable, are now competing fuels and so-called traditional processes. Thus, biomass plays an important role and is considered one of the sources of renewable energy most important of our planet. Biomass accounts for 29.2% of all renewable energy sources. The share of biomass energy from Brazil in the OIE is 13.6%, well above the world average of participation. Various types of pyrolysis processes have been studied in recent years, highlighting the process of fast pyrolysis of biomass to obtain bio-oil. The continuous fast pyrolysis, the most investigated and improved are the fluidized bed and ablative, but is being studied and developed other types in order to obtain Bio-oil a better quality, higher productivity, lower energy consumption, increased stability and process reliability and lower production cost. The stability of the product bio-oil is fundamental to designing consumer devices such as burners, engines and turbines. This study was motivated to produce Bio-oil, through the conversion of plant biomass or the use of its industrial and agricultural waste, presenting an alternative proposal for thermochemical pyrolysis process, taking advantage of particle dynamics in the rotating bed that favors the right gas-solid contact and heat transfer and mass. The pyrolyser designed to operate in a continuous process, a feeder containing two stages, a divisive system of biomass integrated with a tab of coal fines and a system of condensing steam pyrolytic. The prototype has been tested with sawdust, using a complete experimental design on two levels to investigate the sensitivity of factors: the process temperature, gas flow drag and spin speed compared to the mass yield of bio-oil. The best result was obtained in the condition of 570 oC, 25 Hz and 200 cm3/min, temperature being the parameter of greatest significance. The mass balance of the elementary stages presented in the order of 20% and 37% liquid pyrolytic carbon. We determined the properties of liquid and solid products of pyrolysis as density, viscosity, pH, PCI, and the composition characterized by chemical analysis, revealing the composition and properties of a Bio-oil.

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This paper presents a robust model and its simulation to investigate the performance of an AC propulsion system in a rail vehicle for directly returning the regenerative braking power to the feeder substation of an AC traction network. This direct returning method can be an efficient approach for energy recovery if the regenerative braking is reliably applied. However, it is shown that this method can cause undesired voltage fluctuations if the regenerative braking regime or braking location of the rail vehicle change. The load torque on the traction motor (TM) is precisely modelled when pure electrical braking is applied. Different states of the direct torque controlled inverter are modelled when the TM regenerates. A circuit model for the utility grid, load impedances and the traction network is developed to evaluate the network receptivity against the regenerated power. The dynamics of the electromagnetic torque and the fluctuations of the DC-link voltage are investigated for two operational conditions: changes on the regenerative braking regime and changes on the rail vehicle braking location. The results justify how the DC-link voltage dramatically fluctuates with variations of the rail vehicle's operation conditions, whereas the electromagnetic torque is maintained on optimum rates.

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Over the past decade, the growing demand of Grid-connected photo voltaic (GCPV) system has been increasing due to an extensive use of renewable energy technologies for sustainable power generation and distribution. High-penetrated GCPV systems enhance the operation of the network by improving the voltage levels and reducing the active power losses along the length of the feeder. This paper aims to investigate the voltage variations and Total Harmonic Distortion (THD) of a typical GCPV system modelled in Power system simulator, PSS SINCAL with the change of level of PV integrations in a Low Voltage (LV) distribution network. Five different case studies are considered to investigate the impact of PV integrations on LV nodes and the corresponding voltage variations and harmonics. In addition, this paper also explores and benchmarks the voltage improvement techniques by implementing On Load Tap Changer (OLTC) with respective to the main transformer and addition of Shunt Capacitor (SC) at appropriate node points in LV network,

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La transformation du sang de cordon ombilical en une précieuse source de cellules souches a, dès le début des années 1990, donné naissance à une industrie commerciale globale de conservation faisant désormais concurrence à un large réseau de conservation public. Ce mémoire cherche à comprendre et à expliquer les soubassements socio-culturels liés à l’émergence de cette industrie, ainsi qu’à mieux cerner les enjeux éthiques et politiques qu’elle pose. En exposant en premier lieu la manière dont les institutions publiques de conservation de sang de cordon se définissent, et sont généralement définies par les comités bioéthiques, comme étant porteuses des valeurs d’altruisme et de solidarité nationale traditionnellement liées au modèle « redistributif » d’échange de sang et d’organes né au lendemain de la Seconde Guerre mondiale, nous problématisons la manière innovatrice par laquelle les banques privées structurent le rapport entre les mères et leurs propres produits biologiques comme l’expression d’une reconfiguration du lien social et politique caractérisée par l’émergence de nouvelles socialisés. L’hypothèse au coeur de ce mémoire est que celles-ci peuvent être comprises comme l’aboutissant de l‘espoir collectivement partagé par les consommatrices d’améliorer leur propre condition biologique familiale, étant lui-même le fruit d’une financiarisation croissante des sciences du vivant. En analysant le discours « promissif » que représente le matériel promotionnel des banques autologues, notre objectif est alors d’identifier la manière par laquelle les multiples potentialités attribuées au sang de cordon définissent des subjectivités maternelles caractérisées par des obligations morales spécifiques.

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Combinatorial optimization is a complex engineering subject. Although formulation often depends on the nature of problems that differs from their setup, design, constraints, and implications, establishing a unifying framework is essential. This dissertation investigates the unique features of three important optimization problems that can span from small-scale design automation to large-scale power system planning: (1) Feeder remote terminal unit (FRTU) planning strategy by considering the cybersecurity of secondary distribution network in electrical distribution grid, (2) physical-level synthesis for microfluidic lab-on-a-chip, and (3) discrete gate sizing in very-large-scale integration (VLSI) circuit. First, an optimization technique by cross entropy is proposed to handle FRTU deployment in primary network considering cybersecurity of secondary distribution network. While it is constrained by monetary budget on the number of deployed FRTUs, the proposed algorithm identi?es pivotal locations of a distribution feeder to install the FRTUs in different time horizons. Then, multi-scale optimization techniques are proposed for digital micro?uidic lab-on-a-chip physical level synthesis. The proposed techniques handle the variation-aware lab-on-a-chip placement and routing co-design while satisfying all constraints, and considering contamination and defect. Last, the first fully polynomial time approximation scheme (FPTAS) is proposed for the delay driven discrete gate sizing problem, which explores the theoretical view since the existing works are heuristics with no performance guarantee. The intellectual contribution of the proposed methods establishes a novel paradigm bridging the gaps between professional communities.

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La transformation du sang de cordon ombilical en une précieuse source de cellules souches a, dès le début des années 1990, donné naissance à une industrie commerciale globale de conservation faisant désormais concurrence à un large réseau de conservation public. Ce mémoire cherche à comprendre et à expliquer les soubassements socio-culturels liés à l’émergence de cette industrie, ainsi qu’à mieux cerner les enjeux éthiques et politiques qu’elle pose. En exposant en premier lieu la manière dont les institutions publiques de conservation de sang de cordon se définissent, et sont généralement définies par les comités bioéthiques, comme étant porteuses des valeurs d’altruisme et de solidarité nationale traditionnellement liées au modèle « redistributif » d’échange de sang et d’organes né au lendemain de la Seconde Guerre mondiale, nous problématisons la manière innovatrice par laquelle les banques privées structurent le rapport entre les mères et leurs propres produits biologiques comme l’expression d’une reconfiguration du lien social et politique caractérisée par l’émergence de nouvelles socialisés. L’hypothèse au coeur de ce mémoire est que celles-ci peuvent être comprises comme l’aboutissant de l‘espoir collectivement partagé par les consommatrices d’améliorer leur propre condition biologique familiale, étant lui-même le fruit d’une financiarisation croissante des sciences du vivant. En analysant le discours « promissif » que représente le matériel promotionnel des banques autologues, notre objectif est alors d’identifier la manière par laquelle les multiples potentialités attribuées au sang de cordon définissent des subjectivités maternelles caractérisées par des obligations morales spécifiques.

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This paper analyses reconfigurations of play in emergent digital materialities of game design. It extends recent work examining dimensions of hybridity in playful products by turning attention to interfaces, practices and spaces, rather than devices. We argue that the concept of hybrid play relies on predefining clear and distinct digital or material entities that then enter into hybrid situations. Drawing on concepts of the ‘interface’ and ‘postdigital’, we argue the distribution of computing devices creates difficulties for such presuppositions. Instead, we propose thinking these situations through an ‘aesthetic of recruitment’ that is able to accommodate the intensive entanglements and inherent openness of both the social and technical in postdigital play.

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This paper reports on the Transition: Improved Literacy Outcomes Research Study established by the Department of Education and Training (DET). The purpose of the study was to identify the most useful and usable data for educators to access in order to ensure that student literacy learning is maximised during the transition from Primary to Secondary school.1. The research followed a mixed-methods approach, combining a statistically defensible sample of schools selected to represent school types (primary, secondary, combined), locations (rural, regional, urban) and all regions with a survey and follow- up interviews.2. The results are presented as a mixture of statistics, case studies and discussion. The case studies were developed from both survey data and interview data.3. Leaders and teachers overwhelmingly valued teacher judgement (through AusVELS) as the most useful data in understanding students’ strengths and weaknesses, followed by On-Demand testing.4. NAPLAN results were frequently transferred between schools, but were found to be less useful than other data by teachers.5. School leaders and teachers are currently using data for ability streaming, or for tailoring curriculum for individual student needs. A number of schools use the Literacy data for achieving a balance of student abilities within classes.6. Support for access to, and use of, data is mainly manual, with some use of spreadsheets.7. As the number of feeder Primary schools to a single Secondary school increases, data management becomes a much larger burden on the Secondary staff concerned.8. In Secondary schools, there was a clear demand for Literacy data, but these data were not always those that were being provided by their feeder Priamary schools. This mis-match appears to lead to some frustration among Literacy transition staff at both levels of schooling.9. A gap that needs filling is around the nature of the pedagogies at the two school levels. Not knowing, or misunderstanding, the approaches and needs of each level of schooling leads to the passing on of irrelevant Literacy data in some instances.10. The need for a common template for transition data was expressed by many Transition staff, both Primary and Secondary. In some instances the secondary school had set up a local template for this11. It would be advantageous for data to be directly up-loaded or transferred into a system via electronic tools already in use, such as an Excel spreadsheet.12. We would recommend that the capacity to provide some visualisation of data, and the compilation of internal Literacy data such as teacher judgements and AusVELS levels, or additional testing carried out by the school.13. Student background data was seen by many Secondary transition staff as being equally as valuable as more formal Literacy data for determining student needs.

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In species with biparental care, individuals adjust their workload to that of their partner to either compensate or match its investment. Communication within a pair might be crucial for achieving this adjustment. Zebra finches, Taeniopygia guttata, form life-long monogamous pair bonds, in which partners are highly coordinated and both incubate the eggs. When relieving each other during incubation, partners perform a structured call duet at the nest. If this duet functions to coordinate incubation workload, disrupting the pair's usual nest-relief pattern by delaying the male's return to the nest should affect the structure of the duet. Using domesticated birds breeding in a large aviary, we found that delaying the male's return induced shorter duets with higher call rates. In addition, we tracked the location of individuals with a transponder at the nest and the feeder, and showed that these accelerated duets were associated with an increased haste of the partners to take turns incubating and foraging. Females also spent less time incubating during their subsequent shift, and females' time off-nest was best predicted by their mate's calling behaviour in the previous duet. Taken together, these results suggest that duets may function as 'vocal negotiation' over parental care.

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The idea of spacecraft formations, flying in tight configurations with maximum baselines of a few hundred meters in low-Earth orbits, has generated widespread interest over the last several years. Nevertheless, controlling the movement of spacecraft in formation poses difficulties, such as in-orbit high-computing demand and collision avoidance capabilities, which escalate as the number of units in the formation is increased and complicated nonlinear effects are imposed to the dynamics, together with uncertainty which may arise from the lack of knowledge of system parameters. These requirements have led to the need of reliable linear and nonlinear controllers in terms of relative and absolute dynamics. The objective of this thesis is, therefore, to introduce new control methods to allow spacecraft in formation, with circular/elliptical reference orbits, to efficiently execute safe autonomous manoeuvres. These controllers distinguish from the bulk of literature in that they merge guidance laws never applied before to spacecraft formation flying and collision avoidance capacities into a single control strategy. For this purpose, three control schemes are presented: linear optimal regulation, linear optimal estimation and adaptive nonlinear control. In general terms, the proposed control approaches command the dynamical performance of one or several followers with respect to a leader to asymptotically track a time-varying nominal trajectory (TVNT), while the threat of collision between the followers is reduced by repelling accelerations obtained from the collision avoidance scheme during the periods of closest proximity. Linear optimal regulation is achieved through a Riccati-based tracking controller. Within this control strategy, the controller provides guidance and tracking toward a desired TVNT, optimizing fuel consumption by Riccati procedure using a non-infinite cost function defined in terms of the desired TVNT, while repelling accelerations generated from the CAS will ensure evasive actions between the elements of the formation. The relative dynamics model, suitable for circular and eccentric low-Earth reference orbits, is based on the Tschauner and Hempel equations, and includes a control input and a nonlinear term corresponding to the CAS repelling accelerations. Linear optimal estimation is built on the forward-in-time separation principle. This controller encompasses two stages: regulation and estimation. The first stage requires the design of a full state feedback controller using the state vector reconstructed by means of the estimator. The second stage requires the design of an additional dynamical system, the estimator, to obtain the states which cannot be measured in order to approximately reconstruct the full state vector. Then, the separation principle states that an observer built for a known input can also be used to estimate the state of the system and to generate the control input. This allows the design of the observer and the feedback independently, by exploiting the advantages of linear quadratic regulator theory, in order to estimate the states of a dynamical system with model and sensor uncertainty. The relative dynamics is described with the linear system used in the previous controller, with a control input and nonlinearities entering via the repelling accelerations from the CAS during collision avoidance events. Moreover, sensor uncertainty is added to the control process by considering carrier-phase differential GPS (CDGPS) velocity measurement error. An adaptive control law capable of delivering superior closed-loop performance when compared to the certainty-equivalence (CE) adaptive controllers is finally presented. A novel noncertainty-equivalence controller based on the Immersion and Invariance paradigm for close-manoeuvring spacecraft formation flying in both circular and elliptical low-Earth reference orbits is introduced. The proposed control scheme achieves stabilization by immersing the plant dynamics into a target dynamical system (or manifold) that captures the desired dynamical behaviour. They key feature of this methodology is the addition of a new term to the classical certainty-equivalence control approach that, in conjunction with the parameter update law, is designed to achieve adaptive stabilization. This parameter has the ultimate task of shaping the manifold into which the adaptive system is immersed. The performance of the controller is proven stable via a Lyapunov-based analysis and Barbalat’s lemma. In order to evaluate the design of the controllers, test cases based on the physical and orbital features of the Prototype Research Instruments and Space Mission Technology Advancement (PRISMA) are implemented, extending the number of elements in the formation into scenarios with reconfigurations and on-orbit position switching in elliptical low-Earth reference orbits. An extensive analysis and comparison of the performance of the controllers in terms of total Δv and fuel consumption, with and without the effects of the CAS, is presented. These results show that the three proposed controllers allow the followers to asymptotically track the desired nominal trajectory and, additionally, those simulations including CAS show an effective decrease of collision risk during the performance of the manoeuvre.

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RESUMO: O espaço tem sido considerado como uma matéria-prima de interesse para uma pluralidade de ciências. A sua abordagem vai da Física à Geometria, da Economia à Sociologia e assume várias e diversas reflexões teóricas sobre as diferentes temáticas de que é detentor. Se nos primórdios da Sociologia não havia um interesse particular sobre o espaço e, em particular, sobre o fenómeno urbano e pelas suas reconfigurações resultantes da Revolução Industrial, não é menos verdade que a influência exercida hoje sobre a Sociologia e os sociólogos foi, e continua a ser exercida, por parte dos autores que estão na base do edifício da teoria sociológica. E essa influência foi a grande responsável pelo desenvolvimento dos saberes específicos de que são detentoras a Sociologia Espacial, Sociologia Urbana e a Sociologia Rural e a atual Sociologia do Território, que para além das teorias produzidas são ainda responsáveis pelos debates em torno de velhas e de novas questões que a Sociologia procura resolver. ABSTRACT: Space has been considered as a raw material of interest to a plurality of sciences. His approach goes from Physics to Geometry, from Economics to Sociology and assumes several and diverse theoretical reflections on the different themes of which he holds. If in the early days of Sociology there was no particular interest in space and in particular in the urban phenomenon and its reconfigurations resulting from the Industrial Revolution, it is no less true that the influence exerted today on sociology and sociologists was, and continues To be exercised, on the part of the authors who are at the base of the building of the sociological theory. And this influence was the great responsibility for the development of the specific knowledge that holds Space Sociology, Urban Sociology and Rural Sociology and the current Sociology of the Territory, which in addition to the theories produced are still responsible for the debates around old and New questions that Sociology seeks to solve.