882 resultados para ecological dynamics, performance contexts


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Due to high-speed rotation, the problems about rotor mechanics and dynamics for outer rotor high-speed machine are more serious than conventional ones, in view of above problems the mechanical and dynamics analysis for an outer rotor high-speed permanent magnet claw pole motor are carried out. The rotor stress analytical calculation model was derived, then the stress distribution is calculated by finite element method also, which is coincided with that calculated by analytical model. In addition, the stress distribution of outer rotor yoke and PMs considering centrifugal force and temperature effect has been calculated, some influence factors on rotor stress distribution have been analyzed such as pole-arc coefficient and speed. The rotor natural frequency and critical speed were calculated by vibration mode analysis, and its dynamics characteristics influenced by gyroscope effect were analyzed based on Campbell diagram. Based on the analysis results above an outer rotor permanent magnet high-speed claw pole motor is design and verified.

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We present a theoretical description of the generation of ultra-short, high-energy pulses in two laser cavities driven by periodic spectral filtering or dispersion management. Critical in driving the intra-cavity dynamics is the nontrivial phase profiles generated and their periodic modification from either spectral filtering or dispersion management. For laser cavities with a spectral filter, the theory gives a simple geometrical description of the intra-cavity dynamics and provides a simple and efficient method for optimizing the laser cavity performance. In the dispersion managed cavity, analysis shows the generated self-similar behavior to be governed by the porous media equation with a rapidly-varying, mean-zero diffusion coefficient whose solution is the well-known Barenblatt similarity solution with parabolic profile. © 2010 Copyright SPIE - The International Society for Optical Engineering.

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We present a theoretical description of the generation of ultra-short, high-energy pulses in two laser cavities driven by periodic spectral filtering or dispersion management. Critical in driving the intra-cavity dynamics is the nontrivial phase profiles generated and their periodic modification from either spectral filtering or dispersion management. For laser cavities with a spectral filter, the theory gives a simple geometrical description of the intra-cavity dynamics and provides a simple and efficient method for optimizing the laser cavity performance. In the dispersion managed cavity, analysis shows the generated self-similar behavior to be governed by the porous media equation with a rapidly-varying, mean-zero diffusion coefficient whose solution is the well-known Barenblatt similarity solution with parabolic profile. © 2010 American Institute of Physics.

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We present a theoretical description of the generation of ultra-short, high-energy pulses in two laser cavities driven by periodic spectral filtering or dispersion management. Critical in driving the intra-cavity dynamics is the nontrivial phase profiles generated and their periodic modification from either spectral filtering or dispersion management. For laser cavities with a spectral filter, the theory gives a simple geometrical description of the intra-cavity dynamics and provides a simple and efficient method for optimizing the laser cavity performance. In the dispersion managed cavity, analysis shows the generated self-similar behavior to be governed by the porous media equation with a rapidly-varying, mean-zero diffusion coefficient whose solution is the well-known Barenblatt similarity solution with parabolic profile.

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Emulsion-based, resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) has been demonstrated as an alternative technique to deposit conjugated polymer films for photovoltaic applications; yet, a fundamental understanding of how the emulsion target characteristics translate into film properties and solar cell performance is unclear. Such understanding is crucial to enable the rational improvement of organic solar cell (OSC) efficiency and to realize the expected advantages of emulsion-based RIR-MAPLE for OSC fabrication. In this paper, the effect of the primary solvent used in the emulsion target is studied, both experimentally and theoretically, and it is found to determine the conjugated polymer cluster size in the emulsion as well as surface roughness and internal morphology of resulting polymer films. By using a primary solvent with low solubility-in-water and low vapor pressure, the surface roughness of deposited P3HT and PCPDTBT polymer films was reduced to 10 nm, and the efficiency of P3HT:PC61BM OSCs was increased to 3.2% (∼100 times higher compared to the first MAPLE OSC demonstration [ Caricato , A. P. ; Appl. Phys. Lett. 2012 , 100 , 073306 ]). This work unveils the mechanism of polymer film formation using emulsion-based RIR-MAPLE and provides insight and direction to determine the best ways to take advantage of the emulsion target approach to control film properties for different applications.

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This thesis argues that complex adaptive social–ecological systems (SES) theory has important implications for the design of integrated ocean and coastal governance in the EU. Traditional systems of governance have struggled to deal with the global changes, complexity and uncertainties that challenge a transition towards sustainability in Europe’s maritime macro-regions. There is an apparent disconnect between governance strategies for sustainability in Europe’s maritime macro-regions and a sound theoretical basis for them. My premise is that the design of governance architecture for maritime regional sustainability should be informed by SES theory. Therefore, the aim of this research was to gain insight into a multilevel adaptive governance architecture that combines notions of sustainability and development in the context of the Atlantic Europe maritime macro-region. The central research question asked whether it is possible to achieve this insight by using a SES as a framework and analytical tool. This research adopted social ecology and sustainability science as a foundation for understanding society–nature relations. Concepts from complex adaptive systems, SES and resilience theories were integrated into a conceptual framework that guided the investigation and analysis. A study was conducted to conceptualise the European Atlantic social–ecological system (EASES). This was used to represent and understand the Atlantic Europe macro-region as a SES. The study examined the proposition that governance can be focused on building SES resilience to help achieve maritime regional sustainability. A workbook method was developed and used to elicit expert opinion regarding EASES. The study identified sources of resilience and resilience dynamics that require management in the context of multilevel adaptive governance. This research found that the Atlantic Europe macro-region is a key focal level for multilevel adaptive governance architecture. The majority of the findings are specific to Atlantic Europe and not generalisable to other maritime macro-regions in Europe.

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Ce projet de mémoire s’intéresse à la mise en relation du cognitive enhancement observé dans les universités occidentales contemporaines et de la société dans laquelle il s’insère. Nous avons voulu détacher la perspective du phénomène des analyses principalement orientées vers les programmes de sciences de la santé et de droit, ainsi que de l’approche quantitative, clinique, athéorique et somme toute moralisatrice qui lui est usuellement accordée afin d’explorer la nature des pratiques d’usages de psychotropes des étudiants universitaires en sciences humaines et sociales en vue d’augmenter leurs performances cognitives, d’approfondir la compréhension des raisonnements sous-jacents à ces pratiques, puis de resituer ces derniers dans leur contexte élargi. Nous avons interrogé treize étudiants de divers programmes de sciences humaines et sociales consommant, ou ayant déjà consommé, des psychotropes en vue de rehausser leurs performances cognitives en contexte académique. Les résultats suggèrent un écart dans la nature de leurs pratiques d’usage par rapport aux domaines d’études habituellement préconisés en ce sens qu’une grande variété de substances sont considérées comme supports cognitifs ; ensuite, que le recours aux psychotropes dans une visée de performance cognitive s’éloigne des logiques de la nécessité médicale et de la toxicomanie. En premier lieu, le cognitive enhancement est associé par plusieurs à une souffrance psychique liée à une perte de repères existentiels et les étudiants y ont recours dans une optique de compréhension de soi et de quête de repères dans un monde qu’ils ressentent comme instable. En second lieu, la consommation de psychotropes s’apparente davantage à un désir de satisfaire aux conditions incertaines et menaçantes des demandes externes de performance telles qu’ils les appréhendent qu’à un souci de soigner quelque condition médicale de la cognition. Nous pensons que le rapport au psychotrope qu’entretiennent les étudiants universitaires en sciences humaines et sociales s’insère en toute cohérence dans les discours et injonctions contemporaines de performance, en ce sens que leur souffrance psychique individuelle expose les limites de ce que la société attend d’eux.

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Experiments have shown that ocean acidification due to rising atmospheric carbon dioxide concentrations has deleterious effects on the performance of many marine organisms. However, few empirical or modelling studies have addressed the long-term consequences of ocean acidification for marine ecosystems. Here we show that as pH declines from 8.1 to 7.8 (the change expected if atmospheric carbon dioxide concentrations increase from 390 to 750 ppm, consistent with some scenarios for the end of this century) some organisms benefit, but many more lose out. We investigated coral reefs, seagrasses and sediments that are acclimatized to low pH at three cool and shallow volcanic carbon dioxide seeps in Papua New Guinea. At reduced pH, we observed reductions in coral diversity, recruitment and abundances of structurally complex framework builders, and shifts in competitive interactions between taxa. However, coral cover remained constant between pH 8.1 and ~7.8, because massive Porites corals established dominance over structural corals, despite low rates of calcification. Reef development ceased below pH 7.7. Our empirical data from this unique field setting confirm model predictions that ocean acidification, together with temperature stress, will probably lead to severely reduced diversity, structural complexity and resilience of Indo-Pacific coral reefs within this century.

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Recent research has shown that exposure to elevated carbon dioxide (CO2) affects how fishes perceive their environment, affecting behavioral and cognitive processes leading to increased prey mortality. However, it is unclear if increased mortality results from changes in the dynamics of predator-prey interactions or due to prey increasing activity levels. Here we demonstrate that ocean pCO2 projected to occur by 2100 significantly effects the interactions of a predator-prey pair of common reef fish: the planktivorous damselfish Pomacentrus amboinensis and the piscivorous dottyback Pseudochromis fuscus. Prey exposed to elevated CO2 (880 µatm) or a present-day control (440 µatm) interacted with similarly exposed predators in a cross-factored design. Predators had the lowest capture success when exposed to elevated CO2 and interacting with prey exposed to present-day CO2. Prey exposed to elevated CO2 had reduced escape distances and longer reaction distances compared to prey exposed to present-day CO2 conditions, but this was dependent on whether the prey was paired with a CO2 exposed predator or not. This suggests that the dynamics of predator-prey interactions under future CO2 environments will depend on the extent to which the interacting species are affected and can adapt to the adverse effects of elevated CO2.

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This paper examines the moving body as a vehicle for raising ecological consciousness. Due to the modern over-preoccupation with the pursuit of rational aims, human interactions with the surrounding environment increasingly lack conscious awareness. Consequently, in the modern world people tend to lack an ecological consciousness. Nevertheless, the human body is a rich reservoir of ecological significance. From birth, humans are woven into tremendous interconnection with the world. However, humans thrive when their sensitivity to the physical world exists in harmony with their ability to pursue their rational aims. It is the combination of these characteristics that enables humans to survive in capricious surroundings and prosper in a wide array of contexts. Today, the human species faces an unprecedented crisis that threatens to collapse the reciprocality of the ecological bonds bolstering the prosperity of all worldly beings. This paper proposes that it is no longer a rational strategy for people to remain inattentive to their embodied ecological resonance, and that the moving body is an adequate pedagogical site for raising ecological consciousness. Ritualized body movements derived from Chinese traditional cultivation systems such as Taijiquan could orient practitioners to reestablish a perceptual intimacy with the larger cosmic world, thereby raising their ecological consciousness.

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The selected publications are focused on the relations between users, eGames and the educational context, and how they interact together, so that both learning and user performance are improved through feedback provision. A key part of this analysis is the identification of behavioural, anthropological patterns, so that users can be clustered based on their actions, and the steps taken in the system (e.g. social network, online community, or virtual campus). In doing so, we can analyse large data sets of information made by a broad user sample,which will provide more accurate statistical reports and readings. Furthermore, this research is focused on how users can be clustered based on individual and group behaviour, so that a personalized support through feedback is provided, and the personal learning process is improved as well as the group interaction. We take inputs from every person and from the group they belong to, cluster the contributions, find behavioural patterns and provide personalized feedback to the individual and the group, based on personal and group findings. And we do all this in the context of educational games integrated in learning communities and learning management systems. To carry out this research we design a set of research questions along the 10-year published work presented in this thesis. We ask if the users can be clustered together based on the inputs provided by them and their groups; if and how these data are useful to improve the learner performance and the group interaction; if and how feedback becomes a useful tool for such pedagogical goal; if and how eGames become a powerful context to deploy the pedagogical methodology and the various research methods and activities that make use of that feedback to encourage learning and interaction; if and how a game design and a learning design must be defined and implemented to achieve these objectives, and to facilitate the productive authoring and integration of eGames in pedagogical contexts and frameworks. We conclude that educational games are a resourceful tool to provide a user experience towards a better personalized learning performance and an enhance group interaction along the way. To do so, eGames, while integrated in an educational context, must follow a specific set of user and technical requirements, so that the playful context supports the pedagogical model underneath. We also conclude that, while playing, users can be clustered based on their personal behaviour and interaction with others, thanks to the pattern identification. Based on this information, a set of recommendations are provided Digital Anthropology and educational eGames 6 /216 to the user and the group in the form of personalized feedback, timely managed for an optimum impact on learning performance and group interaction level. In this research, Digital Anthropology is introduced as a concept at a late stage to provide a backbone across various academic fields including: Social Science, Cognitive Science, Behavioural Science, Educational games and, of course, Technology-enhance learning. Although just recently described as an evolution of traditional anthropology, this approach to digital behaviour and social structure facilitates the understanding amongst fields and a comprehensive view towards a combined approach. This research takes forward the already existing work and published research onusers and eGames for learning, and turns the focus onto the next step — the clustering of users based on their behaviour and offering proper, personalized feedback to the user based on that clustering, rather than just on isolated inputs from every user. Indeed, this pattern recognition in the described context of eGames in educational contexts, and towards the presented aim of personalized counselling to the user and the group through feedback, is something that has not been accomplished before.