3,608 research outputs found
Lyapunov Exponents without Rescaling and Reorthogonalization
We present a new method for the computation of Lyapunov exponents utilizing
representations of orthogonal matrices applied to decompositions of M or
MM_trans where M is the tangent map. This method uses a minimal set of
variables, does not require renormalization or reorthogonalization, can be used
to efficiently compute partial Lyapunov spectra, and does not break down when
the Lyapunov spectrum is degenerate.Comment: 4 pages, no figures, uses RevTeX plus macro (included). Phys. Rev.
Lett. (in press
Classification of the phases of 1D spin chains with commuting Hamiltonians
We consider the class of spin Hamiltonians on a 1D chain with periodic
boundary conditions that are (i) translational invariant, (ii) commuting and
(iii) scale invariant, where by the latter we mean that the ground state
degeneracy is independent of the system size. We correspond a directed graph to
a Hamiltonian of this form and show that the structure of its ground space can
be read from the cycles of the graph. We show that the ground state degeneracy
is the only parameter that distinguishes the phases of these Hamiltonians. Our
main tool in this paper is the idea of Bravyi and Vyalyi (2005) in using the
representation theory of finite dimensional C^*-algebras to study commuting
Hamiltonians.Comment: 8 pages, improved readability, added exampl
Energy Harvesting Wireless Sensor Networks: Delay Analysis Considering Energy Costs of Sensing and Transmission
Energy harvesting (EH) provides a means of greatly enhancing the lifetime of
wireless sensor nodes. However, the randomness inherent in the EH process may
cause significant delay for performing sensing operation and transmitting the
sensed information to the sink. Unlike most existing studies on the delay
performance of EH sensor networks, where only the energy consumption of
transmission is considered, we consider the energy costs of both sensing and
transmission. Specifically, we consider an EH sensor that monitors some status
environmental property and adopts a harvest-then-use protocol to perform
sensing and transmission. To comprehensively study the delay performance, we
consider two complementary metrics and analytically derive their statistics:
(i) update age - measuring the time taken from when information is obtained by
the sensor to when the sensed information is successfully transmitted to the
sink, i.e., how timely the updated information at the sink is, and (ii) update
cycle - measuring the time duration between two consecutive successful
transmissions, i.e., how frequently the information at the sink is updated. Our
results show that the consideration of sensing energy cost leads to an
important tradeoff between the two metrics: more frequent updates result in
less timely information available at the sink.Comment: submitted for possible journal publicatio
Método do quadrado para estimar a capacidade de suporte de pastagens.
Este folder informa sobre como montar o método do quadrado, o qual consiste no corte da forragem presente dentro de uma área conhecida delimitada por moldura de madeira ou metálica (quadro), lançada ao acaso em diferentes pontos da área a ser avaliada.bitstream/CPAF-RO-2010/14332/1/folder-metododoquadrado-pastagens.pdf1 Folder
Profissão: Zootecnista.
bitstream/CPAF-RO-2010/14385/1/profissao-zootecnista.pdfDisponível em: . Acesso em: 13 jan. 2009. Artigo também publicado em outros canais: Portal do Agronegócio; Página Rural; Agroredenotícias
Utilização da amiréia na alimentação de ruminantes.
Realizou-se um trabalho de revisão de literatura com o intuito de levantar os motivos pelos quais pode ser vantajoso a produção e utilização da amiréia na alimentação de ruminantes.bitstream/CPAF-RO-2010/13294/1/doc126-amireia-.pd
Conceitos básicos de genética de populações.
Conceitos de genética básica; Moléculas de DNA; Conceitos de genética de populações; População genética ou mendeliana; Freqüência genotípica; Freqüência gênica ou alélica; Teorema de Hardy-Weinberg (1908).bitstream/CPAF-RO-2010/12193/1/doc118-geneticadepopulacoes.pd
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