Markovian Models
Mostrando 13-24 de 24 artigos, teses e dissertações.
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13. Markovian models and performance analysis of ARQ schemes on mobile channels / Modelos markovianos e anÃlise de desempenho de esquemas ARQ em canais mÃveis
O presente trabalho desenvolve modelos de canais de estados finitos (CEF) para um sistema de comunicaÃÃo discreto, composto por um modulador digital, um canal com desvanecimento plano (Rayleigh ou Rice) correlacionado no tempo e um demodulador, bem como estuda as propriedades de correlaÃÃo do processo de desvanecimento para analisar o desempenho de proto
Publicado em: 2004
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14. Self-similar LAN/WAN traffic issues on high-speed QoS networks.
During the last decade, the enormous commercial explosion of the Internet has brought up the exhaustive use of Public Telephone Switched Network (PTSN) communication lines by computers (end-users) from all over the world. As a direct consequence of this explosion, a brand new research field, inside the context of the so-called Queuing Theory, has emerged. In
Publicado em: 2004
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15. Algoritmos de programação dinâmica usados em modelos markovianos ocultos (HMMs) / Dynamic programming algorithms used in hidden markov models (HMMs)
Esta tese trata dos algoritmos de programação dinâmica que são usados nos Modelos Markovianos Ocultos (HMMs), perfis-HMMs, aplicados no estudo de seqüências biológicas no campo da Bioinformática. O foco é a investigação de técnicas (métodos ou paradigmas) de economia de espaço que proporcionem a melhor economia de tempo, e que sejam adequadas p
Publicado em: 2004
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16. Variable survival exponents in history-dependent random walks: hard movable reflector
We review recent studies demonstrating a nonuniversal (continuously variable) survival exponent for history-dependent random walks, and analyze a new example, the hard movable partial reflector. These processes serve as simplified models of infection in a medium with a history-dependent susceptibility, and for spreading in systems with an infinite number of
Brazilian Journal of Physics. Publicado em: 2003-09
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17. Sobre dinamica caotica e convergencia em algoritmos de equalização autodidata
The objective of this work is to perform a dynamical analysis of the constant modulus algorithm (CMA) iterative expression. The analysis shows that the CMA, in both deterministic and stochastic versions, can present, besides the usual convergence to fixed point and divergence types of behavior, a very rich dynamical scenario, which includes period-do
Publicado em: 2001
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18. Desenvolvimento de classificadores de máxima verossimilhança e ICM para imagens SAR / Development of maximum likelihood and ICM classifiers for SAR images
The purpose of this study is to implement, test and apply a Maximurn Likelihood Classifier (MLC) and a userfriendly contextual Markovian classifier, which use the distributions most appropriate to the Synthethic Aperture Radar (SAR) data. This study presents the main distributions to the SAR data and how several of these distributions arise from the multipli
Publicado em: 1996
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19. Encaminhamento de chamadas telefonicas : analise de desempenho
This work presents a study about telephone networks routing plan assignment problems. Basically, two problems are studied: minimal cost routing plan assignment and optimal performance routing plan assignment. The junction network dimensioning problem is formulated as a multi-commodity minimal cost flux problem. The solution ofthis problem leads to a routing
Publicado em: 1994
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20. Evolutionary demographic models for mortality plateaus
Plateaus in the age pattern of hazard functions at extreme ages have been discovered in large populations of medflies, Drosophila, nematodes, and people. Mueller and Rose [(1996) Proc. Natl. Acad. Sci. USA 93, 15249–15253] have proposed several age-structured demographic models to represent effects of mutation accumulation and antagonistic pleiotropy on ra
The National Academy of Sciences.
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21. Conformational-relaxation models of single-enzyme kinetics
Fluorescent spectroscopy experiments with single-enzyme molecules yield a large volume of statistical data that can be analyzed and interpreted using stochastic models of enzyme action. Here, we present two models, each based on the mechanism that an enzyme molecule must pass through a sequence of conformational transformations to complete its catalytic turn
National Academy of Sciences.
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22. Differential Regulation of Action Potentials by Inactivating and Noninactivating BK Channels in Rat Adrenal Chromaffin Cells
Large-conductance Ca2+-activated K+ (BK) channels can regulate cellular excitability in complex ways because they are able to respond independently to two distinct cellular signals, cytosolic Ca2+ and membrane potential. In rat chromaffin cells (RCC), inactivating BKi and noninactivating (BKs) channels differentially contribute to RCC action potential (AP) f
The Biophysical Society.
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23. Diffusion models of ion-channel gating and the origin of power-law distributions from single-channel recording.
The lifetimes of the unitary currents from ion channels, as revealed from single-channel recording, are traditionally thought to follow exponential or multiexponential distributions. The interpretation of these event-time distributions is that the gating process follows Markov kinetics among a small number of states. There is recent evidence, however, that c
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24. Surface site diffusion and reaction on molecular “organizates” and colloidal catalysts: A geometrical perspective
We study surface-mediated, diffusion-controlled reactive processes on particles whose overall geometry is homeomorphic to a sphere. Rather than assuming that a coreactant can diffuse freely over the surface of the particle to a target site (reaction center), we consider the case where the coreactant can migrate only among N - 1 satellite sites that are netwo