933 resultados para Analog-to-digital converter (ADC)


Relevância:

100.00% 100.00%

Publicador:

Resumo:

O presente relatório foi realizado no âmbito da unidade curricular da Prática de Ensino Supervisionada (PES), inserida no plano de estudos do curso de Mestrado em Educação Pré-Escolar e Ensino do 1.º Ciclo do Ensino Básico, da Escola Superior de Educação de Bragança, do Instituto Politécnico de Bragança. Com este relatório, pretendemos apresentar as experiências de ensino aprendizagem que consideramos relevantes e representativas do trabalho desenvolvido com as crianças ao longo da nossa PES em ambos os contextos educativos. Estas reportam-se à descrição, reflexão e investigação acerca da ação educativa. A prática pedagógica foi desenvolvida na Educação Pré-Escolar (EPE), com um grupo de 25 crianças, com idades de 3 e 4 anos e, no 1.º Ciclo do Ensino Básico (1.º CEB), com um grupo de 10 crianças pertencentes ao 1.º ano de escolaridade. O contexto na Educação Pré-Escolar caraterizava-se por ser uma Instituição Particular de Solidariedade Social (IPSS) e o contexto de 1.º Ciclo do Ensino Básico pertencia à rede pública. No decorrer da ação educativa, tivemos em conta a articulação curricular, onde mantivemos sempre presente as necessidades das crianças, os seus interesses e ritmos de aprendizagem. Para tal, apoiamo-nos nos documentos oficiais e orientadores da prática pedagógica, sendo estes as Orientações Curriculares para a Educação Pré-Escolar e o Programa Nacional do 1.º ano do 1.º Ciclo do Ensino Básico, indo ao encontro da questão problema: De que forma os diferentes suportes (papel/digital) motivam as crianças no seu processo de leitura em contexto jardim de infância e no 1.º Ciclo do Ensino Básico? Para dar resposta delineamos os seguintes objetivos: (i) Perceber se o tipo de suporte em que as crianças efetuam as suas leituras influencia a sua motivação; (ii) Perceber se a leitura em suporte digital contribui para o desenvolvimento do gosto pela leitura; (iii) Verificar se a leitura em suporte papel permite uma maior motivação na criança em relação ao suporte digital. Os dados foram recolhidos no decorrer das intervenções, através da observação, com recurso às notas de campo, ao registo fotográfico e ao questionário. A apresentação das experiências de ensino/aprendizagem presentes neste relatório traduzem-se num processo descritivo, interpretativo e reflexivo, enquadrado numa abordagem qualitativa. É de salientar que ao longo da nossa prática educativa adotamos uma atitude reflexiva e crítica face ao nosso trabalho, tornando-nos observadores ativos neste processo, assumindo ao mesmo tempo, o papel de investigadoras.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Les informations relatives aux cryptomonnaies sont susceptibles de changer à l'avenir tant cette matière est nouvelle et encore peu ancrée dans le droit. Ce mémoire est une réflexion sur l'essor du Bitcoin et des cryptomonnaies à leurs débuts, alors même que le droit cherche à s'accaparer ces nouvelles technologies, à les intégrer dans son système préexistant.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Les informations relatives aux cryptomonnaies sont susceptibles de changer à l'avenir tant cette matière est nouvelle et encore peu ancrée dans le droit. Ce mémoire est une réflexion sur l'essor du Bitcoin et des cryptomonnaies à leurs débuts, alors même que le droit cherche à s'accaparer ces nouvelles technologies, à les intégrer dans son système préexistant.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Thesis (Master's)--University of Washington, 2016-06

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A proposal to increase the existing residential LV grid voltage from 230 V has been made in order to increase existing network capacity. A power-electronic AC-AC converter is then used to provide 230 V at each property. Several constraints such as temperature rise at the converter location lead to a converter design requiring very high efficiency. In this paper results from a recent feasibility study in terms of LV network capacity increase are presented along with the design and testing of a SiC based 1 kW, AC/AC prototype module, which forms the basis of a much larger 15 kW multi-module converter.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A proposal to increase the existing residential LV grid voltage from 230 V to 300 V has been made in order to increase existing network capacity. A power-electronic AC-AC converter is then used to provide 230 V at each property. The equipment can also provide power-quality improvements to the network and load. Several constraints such as temperature rise at the converter location lead to a converter design requiring very high efficiency. In this paper different AC/AC converter topologies are presented which compares the power quality benefits, size and efficiency of each converter. The design and the control technique of the most suitable topology are verified using simulation and preliminary experimentally results of prototype hardware are also included. © 2013 IEEE.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper is part of a project which aims to research the opportunities for the re-use of batteries after their primary use in low and ultra low carbon vehicles on the electricity grid system. One potential revenue stream is to provide primary/secondary/high frequency response to National Grid through market mechanisms via DNO's or Energy service providers. Some commercial battery energy storage systems (BESS) already exist on the grid system, but these tend to use costly new or high performance batteries. Second life batteries should be available at lower cost than new batteries but reliability becomes an important issue as individual batteries may suffer from degraded performance or failure. Therefore converter topology design could be used to influence the overall system reliability. A detailed reliability calculation of different single phase battery-to-grid converter interfacing schemes is presented. A suitable converter topology for robust and reliable BESS is recommended.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Full text This Proceedings volume contains selected papers from the Fourth International CIRP-sponsored, Conference on Digital Enterprise Technology (DET2007), which was held at the University of Bath, UK, 19–21 September 2007. All selected papers have been suitably enhanced for publication in the Journal and have undergone full review. Digital enterprise technology (DET) is ‘the collection of systems and methods for the digital modelling and analysis of the global product development and realization process, in the context of lifecycle management.’ The principal aim of the DET concept is to provide a coherent context for the development and integration of the various digital technologies that underpin modern design and manufacturing. These technologies can be classified according to the following five key areas. 1. Distributed and collaborative design. 2. Process modelling and process planning. 3. Advanced factory design and modelling. 4. Physical-to-digital environment integrators–verification. 5. Enterprise integration technologies. This special issue is representative of the wide breadth of the DET concept including; a comprehensive review of digital engineering, design processes, digital modelling of machine tools, forming, robotics and machining processes, verification and metrology, and dynamic networks. It is particularly pleasing to see the development of metrology as a key aspect of modern manufacturing technology, linking design intent to process capability. The papers published herein will facilitate the exploration of new and evolving research concepts by the international research community and will influence the development of international standards for the application of DET technologies.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The humanity reached a time of unprecedented technological development. Science has achieved and continues to achieve technologies that allowed increasingly to understand the universe and the laws which govern it, and also try to coexist without destroying the planet we live on. One of the main challenges of the XXI century is to seek and increase new sources of clean energy, renewable and able to sustain our growth and lifestyle. It is the duty of every researcher engage and contribute in this race of energy. In this context, wind power presents itself as one of the great promises for the future of electricity generation . Despite being a bit older than other sources of renewable energy, wind power still presents a wide field for improvement. The development of new techniques for control of the generator along with the development of research laboratories specializing in wind generation are one of the key points to improve the performance, efficiency and reliability of the system. Appropriate control of back-to-back converter scheme allows wind turbines based on the doubly-fed induction generator to operate in the variable-speed mode, whose benefits include maximum power extraction, reactive power injection and mechanical stress reduction. The generator-side converter provides control of active and reactive power injected into the grid, whereas the grid-side converter provides control of the DC link voltage and bi-directional power flow. The conventional control structure uses PI controllers with feed-forward compensation of cross-coupling dq terms. This control technique is sensitive to model uncertainties and the compensation of dynamic dq terms results on a competing control strategy. Therefore, to overcome these problems, it is proposed in this thesis a robust internal model based state-feedback control structure in order to eliminate the cross-coupling terms and thereby improve the generator drive as well as its dynamic behavior during sudden changes in wind speed. It is compared the conventional control approach with the proposed control technique for DFIG wind turbine control under both steady and gust wind conditions. Moreover, it is also proposed in this thesis an wind turbine emulator, which was developed to recreate in laboratory a realistic condition and to submit the generator to several wind speed conditions.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In the shallow continental shelf in Northeastern Rio Grande do Norte - Brazil, important underwater geomorphological features can be found 6km from the coastline. They are coral reefs, locally known as “parrachos”. The present study aims to characterize and analyze the geomorphological feature as well as the ones of the benthic surface, and the distribution of biogenic sediments found in parrachos at Rio do Fogo and associated shallow platforms, by using remote sensing products and in situ data collections. This was made possible due to sedimentological, bathymetric and geomorphological maps elaborated from composite bands of images from the satellite sensors ETM+/Landsat-7, OLI/Landsat-8, MS/GeoEye and PAN/WordView-1, and analysis of bottom sediments samples. These maps were analyzed, integrally interpreted and validated in fieldwork, thus permitting the generation of a new geomorphological zoning of the shallow shelf in study and a geoenvironmental map of the Parrachos in Rio do Fogo. The images used were subject to Digital Image Processing techniques. All obtained data and information were stored in a Geographic Information System (GIS) and can become available to the scientific community. This shallow platform has a carbonate bottom composed mostly by algae. Collected and analyzed sediment samples can be classified as biogenic carbonatic sands, as they are composed 75% by calcareous algae, according to the found samples. The most abundant classes are green algae, red algae, nonbiogenic sediments (mineral grains), ancient algae and molluscs. At the parrachos the following was mapped: Barreta Channel, intertidal reefs, submerged reefs, the spur and grooves, the pools, the sandy bank, the bank of algae, sea grass, submerged roads and Rio do Fogo Channel. This work presents new information about geomorphology and evolution in the study area, and will be guiding future decision making in the handling and environmental management of the region

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Traditional classrooms have been often regarded as closed spaces within which experimentation, discussion and exploration of ideas occur. Professors have been used to being able to express ideas frankly, and occasionally rashly while discussions are ephemeral and conventional student work is submitted, graded and often shredded. However, digital tools have transformed the nature of privacy. As we move towards the creation of life-long archives of our personal learning, we collect material created in various 'classrooms'. Some of these are public, and open, but others were created within 'circles of trust' with expectations of privacy and anonymity by learners. Taking the Creative Commons license as a starting point, this paper looks at what rights and expectations of privacy exist in learning environments? What methods might we use to define a 'privacy license' for learning? How should the privacy rights of learners be balanced with the need to encourage open learning and with the creation of eportfolios as evidence of learning? How might we define different learning spaces and the privacy rights associated with them? Which class activities are 'private' and closed to the class, which are open and what lies between? A limited set of set of metrics or zones is proposed, along the axes of private-public, anonymous-attributable and non-commercial-commercial to define learning spaces and the digital footprints created within them. The application of these not only to the artefacts which reflect learning, but to the learning spaces, and indeed to digital media more broadly are explored. The possibility that these might inform not only teaching practice but also grading rubrics in disciplines where public engagement is required will also be explored, along with the need for consideration by educational institutions of the data rights of students.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Into the Bends of Time is a 40-minute work in seven movements for a large chamber orchestra with electronics, utilizing real-time computer-assisted processing of music performed by live musicians. The piece explores various combinations of interactive relationships between players and electronics, ranging from relatively basic processing effects to musical gestures achieved through stages of computer analysis, in which resulting sounds are crafted according to parameters of the incoming musical material. Additionally, some elements of interaction are multi-dimensional, in that they rely on the participation of two or more performers fulfilling distinct roles in the interactive process with the computer in order to generate musical material. Through processes of controlled randomness, several electronic effects induce elements of chance into their realization so that no two performances of this work are exactly alike. The piece gets its name from the notion that real-time computer-assisted processing, in which sound pressure waves are transduced into electrical energy, converted to digital data, artfully modified, converted back into electrical energy and transduced into sound waves, represents a “bending” of time.

The Bill Evans Trio featuring bassist Scott LaFaro and drummer Paul Motian is widely regarded as one of the most important and influential piano trios in the history of jazz, lauded for its unparalleled level of group interaction. Most analyses of Bill Evans’ recordings, however, focus on his playing alone and fail to take group interaction into account. This paper examines one performance in particular, of Victor Young’s “My Foolish Heart” as recorded in a live performance by the Bill Evans Trio in 1961. In Part One, I discuss Steve Larson’s theory of musical forces (expanded by Robert S. Hatten) and its applicability to jazz performance. I examine other recordings of ballads by this same trio in order to draw observations about normative ballad performance practice. I discuss meter and phrase structure and show how the relationship between the two is fixed in a formal structure of repeated choruses. I then develop a model of perpetual motion based on the musical forces inherent in this structure. In Part Two, I offer a full transcription and close analysis of “My Foolish Heart,” showing how elements of group interaction work with and against the musical forces inherent in the model of perpetual motion to achieve an unconventional, dynamic use of double-time. I explore the concept of a unified agential persona and discuss its role in imparting the song’s inherent rhetorical tension to the instrumental musical discourse.