Time Frequency Representation
Mostrando 1-12 de 31 artigos, teses e dissertações.
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1. A novel transition identification mechanism for the diesel blending and distribution scheduling problem using the discrete time representation with two time-scales granularity
ABSTRACT Transitions between tasks arise in many different scheduling problems. Sometimes transitions are undesired because they incur costs; sometimes they are undesired because they require setup time, and sometimes both. In one way or the other, frequently, transitions need to be identified and penalized in order for their frequency to be minimized. The p
Braz. J. Chem. Eng.. Publicado em: 2017-10
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2. Semi-analytical formulation for a Unified Time and Frequency Antenna Characterization
AbstractThe definition of parameters that characterize the radiation of electric and magnetic fields for antennas in the time and frequency domain on an unified representation is proposed. The formulation uses a straightforward semi-analytical formulation that can be subsequently applied on the analysis of excited antennas for an arbitrary source with tempor
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2015-06
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3. Characterization and Modeling of the Viscoelastic Behavior of a Self-Adhesive Rubber Using Dynamic Mechanical Analysis Tests
ABSTRACT: The goal of this study is twofold. The first one is to assess the applicability of approaches based on dynamic-mechanical analysis to investigate the viscoelastic properties of a self-adhesive synthetic rubber. The second goal is to identify the parameters of a viscoelastic model which accurately represents the frequency-dependent mechanical proper
J. Aerosp. Technol. Manag.. Publicado em: 2015-06
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4. Métodos de reamostragem de séries temporais baseados em wavelets. / Resampling methods for time series based on wavelets.
This paper reviews resampling methods based on wavelets as an alternative to the classic approaches which are, made in the time and frequency domains. These methods, known in the literature as wavestrap and wavestrapping, make use, respectively, of the discrete wavelet transform (DWT) and of the discrete wavelet packet transform (DWPT). Since only few result
Publicado em: 2010
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5. Estabilização de oscilações de potencia de linhas de intercambio atraves de um elo de corrente continua / Stabilization of power lines interchange oscillations through a direct-current link
When an interconnected alternate-current power system suffers variations of loads, its frequency can exhibit an oscillatory behavior. If this system possesses a direct-current link in parallel with the inter-tie lines, this effect could be decreased, due to the link current controller action. This work presents a study that evaluates the efficiency of DC lin
Publicado em: 2009
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6. Estudo da expressão de eventos de transferência de posse na interlíngua de brasileiros aprendizes de inglês
Based on Construction Grammar theory (GOLDBERG, 1995, 2006) and on the Interlanguage Hypothesis (SELINKER, 1972), the present study has sought to investigate the acquisition of the English Ditransitive Construction by 62 native speakers of Brazilian Portuguese, grouped according to their proficiency level (beginner, intermediate and advanced) in the English
Publicado em: 2009
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7. Adequabilidade dos esfregaços cervicais frente aos principais fatores pré-laboratoriais que podem interferir na análise do exame citopatológico. / Adequacy of cervical smears before the main factors pre-lab that can interfere with the analysis of cervical screening.
Background: Cervical cancer in Brazil has one of the highest incidence rates. Screening this neoplasia is effective when a cytopathological test stained by Papanicolaou method is performed. However, the quality of cytopathological samples directly influences the screening effectiveness. Eventhough, this method has been criticized due to the high rates of fal
Publicado em: 2009
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8. História natural e interação flores-besouros em espécies de Cerrado / Natural history and flower-beetle interactions in Cerrado species
Plant-animal interactions, such as pollination, are a key element in many terrestrial communities. The study of who interacts with whom is an important approach for understanding ecological and evolutionary processes. In some tropical communities, up to one quarter of all plant species may be pollinated by beetles. They are an ancient and much diversified in
Publicado em: 2009
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9. A constraint-based model to support electronic TV network design
Electronic Television Network Design is well established when electronic physics concepts and computer techniques joint trough mathematical equations and geometrics concepts, to represent real effects. Even though, the two fields have significant different concepts. This research has as objective to propose one approach constraint-based data model, to suppor
Publicado em: 2008
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10. Avaliação de modelos fotoquímicos de qualidade do ar e estudo das circulações atmosféricas nos processos de dispersão de poluentes / Evaluation of air quality photochemical models and atmospheric circulations in the pollution dispersion processes.
Throughout numerical simulations and near to surface measurements of pollutants concentrations, in this work some meteorological situations of relevance for high ozone concentrations episodes over the Metropolitan Area of Sao Paulo (MASP) were studied., between 1999 and 2006. Firstly, two photochemical models, CIT and SPM-BRAMS, were evaluated in the sense o
Publicado em: 2008
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11. A unified discrete-time approach to the state space representation of aeroelastic systems.
In complex flow situations, it is common to use numerical tools to evaluate the aerodynamic unsteady behavior. The present work presents an alternate formulation for the state space representation of aeroelastic systems based on digital control theory that is shown to be effective and accurate for the coupling of numerical solutions with such systems. The ap
Publicado em: 2007
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12. Tempo de processamento para a leitura de palavras e para a nomeação de figuras em crianças leitoras e não leitoras / Processing time for word reading and picture naming in readers and non-readers children
The development and the processing of word reading and picture naming in readers and non-readers have been based on cognitive models of information processing. Accuracy of answers and processing time must be considered for reading and naming. Processing time refers to latency and length of oral emissions. The aim of this study was to analyze processing time
Publicado em: 2007