Hilbert Series
Mostrando 1-10 de 10 artigos, teses e dissertações.
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1. Time-frequency analysis of Hilbert spectrum of pressure fluctuation time series in a Kenics Static Mixer based on empirical mode decomposition
The turbulent flow in a Kenics Static Mixer (KSM) was intensified under the mutual-coupling effect between the twisted leaves and the tube-wall. In order to understand the intrinsic features of turbulent flow in KSM, the Hilbert-Huang Transform based on Empirical Mode Decomposition were first introduced to describe the time-frequency features of the pressure
Brazilian Journal of Chemical Engineering. Publicado em: 2012-03
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2. Séries de Hilbert de algumas álgebras associadas a grafos orientados via cohomologia de conjuntos parcialmente ordenados / Hilbert series of algebras associated to directed graphs using cohomology of partially ordered sets
We begin with a definition of the algebras Qn, who originated the study of algebra associated to directed graphs. Then, we define key concepts such as Hilbert series, graded and filtered algebras. Among the quadratic algebras, we introduce the Koszul algebras. The Hilbert series is a useful tool to study the Koszulity of a quadratic algebra. The homological
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 31/08/2011
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3. Séries de Hilbert de algumas álgebras associadas a grafos orientados via cohomologia de conjuntos parcialmente ordenados / Hilbert series of algebras associated to directed graphs using cohomology of partially ordered sets
Começamos definindo as álgebras Qn, que originaram o estudo das álgebras associadas a grafos orientados em níveis. Em seguida, definimos conceitos importantes, tais como séries de Hilbert , álgebras graduadas e álgebras filtradas. Entre as álgebras quadráticas, introduzimos as álgebras de Koszul. As séries de Hilbert são instrumentos úteis para
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 31/08/2011
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4. Sistema automÃtico para anÃlise de variabilidade da freqÃencia cardÃaca / Automatic system for analysis of heart rate variability
This dissertation describes a system for analysis of heart rate variability through metrics on time and frequency domain and by non-linear methodology, which is initiated by the process of segmentation of the QRS complex of the electrocardiogram signal. The motivation for this work is the analysis of the influence from the algorithms of beat segmentation and
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 08/10/2008
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5. Analysis of auditory brainstem response through instantaneous attributes of time-series / Análise de potenciais evocados auditivos de tronco encefálico através de atributos instantâneos de séries temporais
The extraction of signal components from Auditory Brainstem Response (ABR), referred to as Jewett waves, is an important step in studies regarding the investigation of the behavior of the auditory system. However, this evaluation is complex and depends on the experience of the specialist. In this context, the objectives of this research are to compare ABR an
Publicado em: 2007
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6. Isometria entre espaços de Wiener abstratos
In this monograph we construct an isomorphism of abstract Wiener space (A WS) between the canonical Wiener space given by the trajectories of the Brownian motion (i, BeM, Co[O,I]) and the A WS (i, lz, V) defined over a normed vector space given by a subset ofthe space ofsequences ofreal numbers. Moreover, we present a generalization of Paul Levy s Wiener mea
Publicado em: 2001
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7. SOBRE RAIOS ESPECTRAIS DE UMA CLASSE DE TRANSFORMAÇÕES DE OPERADORES / ON SPECTRAL RADIUS OF A CLASS OF OPERATORS TRANSFORMATIONS
As transformações F e F(diferente) surgiram associados ao problema de estabilidade em média-quadrática de sistemas bilineares discretos de dimensão infinita evoluindo em espaços de Hilbert separáveis, tendo sido originariamente definidas através de séries infinitas na álgebra de Banach dos operadores lineares e limitados no espaço de Hilbert em qu
Publicado em: 1993
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8. Detecção e caracterização de não linearidades em sistemas mecanicos
This work presents a method for the detection of non -linearities in a physically realizable system based on the Hilbert transform and the implementation of the quadratic mathematical model in the frequency domain. This model is non-parametric, based on the Volterra and Wiener series and uses the spectral and biespectral analysis to obtain the frequency resp
Publicado em: 1990
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9. Hilbert series, Howe duality, and branching rules
Let λ be a partition, with l parts, and let Fλ be the irreducible finite dimensional representation of GL(m) associated to λ when l ≤ m. The Littlewood Restriction Rule describes how Fλ decomposes when restricted to the orthogonal group O(m) or to the symplectic group Sp(m/2) under the condition that l ≤ m/2. In this paper, this result is extended to
The National Academy of Sciences.
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10. Engineering analysis of biological variables: An example of blood pressure over 1 day
Almost all variables in biology are nonstationarily stochastic. For these variables, the conventional tools leave us a feeling that some valuable information is thrown away and that a complex phenomenon is presented imprecisely. Here, we apply recent advances initially made in the study of ocean waves to study the blood pressure waves in the lung. We note fi
The National Academy of Sciences.