336 research outputs found

    Radar signal categorization using a neural network

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    Neural networks were used to analyze a complex simulated radar environment which contains noisy radar pulses generated by many different emitters. The neural network used is an energy minimizing network (the BSB model) which forms energy minima - attractors in the network dynamical system - based on learned input data. The system first determines how many emitters are present (the deinterleaving problem). Pulses from individual simulated emitters give rise to separate stable attractors in the network. Once individual emitters are characterized, it is possible to make tentative identifications of them based on their observed parameters. As a test of this idea, a neural network was used to form a small data base that potentially could make emitter identifications

    Electrohydrodynamic Solutions for Nematic Liquid Crystals

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    We have solved the boundary value problem associated with the Williams domain mode and the variable grating mode in nematic liquid crystals. Using linearized electrohydrodynamic equations of motion, standard constitutive relations, and experimentally observed material constants, we reproduce the significant experimental observations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70851/2/APPLAB-20-11-415-1.pd

    Phylogenetic Analysis of Morpho Butterflies (Nymphalidae, Morphinae): Implications for Classification and Natural History

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    Phylogenetic analysis and review of Panacea and Batesia butterflies (Nymphalidae)

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    Phylogenetic analysis of 53 morphological characte rs for five species of Panacea and Batesia hypochlora supports the separation of the two genera and showed that the monotypic genus Batesia is basal to Panacea. Male genitalia were Ilniform within Panacea and characters inir)f)llative for phylogeny reconstruction were restricted to wing coloration. Illustrations of adults and genitalia, a brief diagnosis, and distributions are provided le)r each species

    Global MHD simulation of flux transfer events at the high-latitude magnetopause observed by the cluster spacecraft and the SuperDARN radar system

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    A global magnetohydrodynamic numerical simulation is used to study the large-scale structure and formation location of flux transfer events (FTEs) in synergy with in situ spacecraft and ground-based observations. During the main period of interest on the 14 February 2001 from 0930 to 1100 UT the Cluster spacecraft were approaching the Northern Hemisphere high-latitude magnetopause in the postnoon sector on an outbound trajectory. Throughout this period the magnetic field, electron, and ion sensors on board Cluster observed characteristic signatures of FTEs. A few minutes delayed to these observations the Super Dual Auroral Radar Network (SuperDARN) system indicated flow disturbances in the conjugate ionospheres. These “two-point” observations on the ground and in space were closely correlated and were caused by ongoing unsteady reconnection in the vicinity of the spacecraft. The three-dimensional structures and dynamics of the observed FTEs and the associated reconnection sites are studied by using the Block-Adaptive-Tree-Solarwind-Roe-Upwind-Scheme (BATS-R-US) MHD code in combination with a simple open flux tube motion model (Cooling). Using these two models the spatial and temporal evolution of the FTEs is estimated. The models fill the gaps left by measurements and allow a “point-to-point” mapping between the instruments in order to investigate the global structure of the phenomenon. The modeled results presented are in good correlation with previous theoretical and observational studies addressing individual features of FTEs

    Fleming's bound for the decay of mixed states

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    Fleming's inequality is generalized to the decay function of mixed states. We show that for any symmetric hamiltonian hh and for any density operator ρ\rho on a finite dimensional Hilbert space with the orthogonal projection Π\Pi onto the range of ρ\rho there holds the estimate \Tr(\Pi \rme^{-\rmi ht}\rho \rme^{\rmi ht}) \geq\cos^{2}((\Delta h)_{\rho}t) for all real tt with (Δh)ρtπ/2.(\Delta h)_{\rho}| t| \leq\pi/2. We show that equality either holds for all tRt\in\mathbb{R} or it does not hold for a single tt with 0<(Δh)ρtπ/2.0<(\Delta h)_{\rho}| t| \leq\pi/2. All the density operators saturating the bound for all tR,t\in\mathbb{R}, i.e. the mixed intelligent states, are determined.Comment: 12 page

    On the existence of effective potentials in time-dependent density functional theory

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    We investigate the existence and properties of effective potentials in time-dependent density functional theory. We outline conditions for a general solution of the corresponding Sturm-Liouville boundary value problems. We define the set of potentials and v-representable densities, give a proof of existence of the effective potentials under certain restrictions, and show the set of v-representable densities to be independent of the interaction.Comment: 13 page

    Produção de ovos em reprodutoras de frangos de corte submetidas a diferentes horários de alimentação com pico de postura no verão.

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    Consequência do horário de alimentação na produção e na qualidade do ovo fértil.

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    bitstream/item/58317/1/CUsersPiazzonDocuments286.pd
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