15,484 research outputs found
A Time-Periodic Lyapunov Approach for Motion Planning of Controllable Driftless Systems on SU(n)
For a right-invariant and controllable driftless system on SU(n), we consider
a time-periodic reference trajectory along which the linearized control system
generates su(n): such trajectories always exist and constitute the basic
ingredient of Coron's Return Method. The open-loop controls that we propose,
which rely on a left-invariant tracking error dynamics and on a fidelity-like
Lyapunov function, are determined from a finite number of left-translations of
the tracking error and they assure global asymptotic convergence towards the
periodic reference trajectory. The role of these translations is to avoid being
trapped in the critical region of this Lyapunov-like function. The convergence
proof relies on a periodic version of LaSalle's invariance principle and the
control values are determined by numerical integration of the dynamics of the
system. Simulations illustrate the obtained controls for and the
generation of the C--NOT quantum gate.Comment: Submitte
Classical and quantum wormholes in a flat -decaying cosmology
We study the classical and quantum wormholes for a flat {\it Euclidean}
Friedmann-Robertson-Walker metric with a perfect fluid including an ordinary
matter source plus a source playing the role of dark energy (decaying
cosmological term). It is shown that classical wormholes exist for this model
and the quantum version of such wormholes are consistent with the Hawking-Page
conjecture for quantum wormholes as solutions of the Wheeler-DeWitt equation.Comment: 8 pages, 4 figures, accepted for publication in IJT
Cuidados no vinhedo que antecedem à colheita, para obtenção de uva de qualidade.
bitstream/item/140428/1/cuidados-no-vinhedo-que-antecedem.pd
Campaign Advertising and Election Outcomes: Quasi-Natural Experiment Evidence from Gubernatorial Elections in Brazil
Whether campaign advertising influences election outcomes is an open question; a paradox given the amount spent on campaigning in general and TV advertising in particular. We argue that such “absence of documentation” is due to the focus of the empirical literature on the United States, in which the allocation of campaign spending and advertising is decentralized. We explore a quasinatural experiment that enables us to mitigate the omitted variables and reverse causality problems caused by decentralized allocation. In Brazil, gubernatorial elections work in a two-round system. In the first round, candidates’ TV time shares are determined by their coalitions’ share of seats in the National Parliament. In the second round, TV time is split equally between the first-round winner and runner-up. Using differences between rounds as a source of variation, we find a large causal effect of TV advertising on election outcomes.TV Advertising; Campaign Spending; Election Outcomes; Endogeneity; Quasi-Natural Experiments
Estudo dos efeitos dos componentes do meio de cultura para crescimento celular de Xanthomonas campestris NYDA B-10.
Rastreabilidade na etapa indústria da Produção Integrada de Uva para Processamento.
O propĂłsito deste trabalho Ă© apresentar os pontos chaves identificados junto a trĂŞs vinĂcolas da Serra GaĂşcha no processo de validação do Caderno do Estabelecimento VinĂcola (CEV), na safra 2013/2014, abordando os pontos cruciais para a rastreabilidade
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