58 resultados para 7798


Relevância:

10.00% 10.00%

Publicador:

Resumo:

The large scale fading of wireless mobile communications links is modelled assuming the mobile receiver motion is described by a dynamic linear system in state-space. The geometric relations involved in the attenuation and multi-path propagation of the electric field are described by a static non-linear mapping. A Wiener system subspace identification algorithm in conjunction with polynomial regression is used to identify a model from time-domain estimates of the field intensity assuming a multitude of emitters and an antenna array at the receiver end.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Two homometallic complexes containing two and three ruthenium polypyridyl units linked by amino acid lysine (Lys) and the related dipeptide (LysLys) were synthesized and their electrochemical, spectroscopic, and electrochemiluminescence (ECL) properties were investigated. The electrochemical and photophysical data indicate that the two metal complexes largely retain the electronic properties of the reference compound for the separate ruthenium moieties in the two bridged complexes, [4-carboxypropyl-4'-methyl-2,2'-bipyridine]bis(2,2'-bipyridine)ruthenium(II) complex. The ECL studies, performed in aqueous media in the presence of tri-n-propylamine as co-reactant, show that the ECL intensity increases by 30% for the dinuclear and trinuclear complexes compared to the reference. Heterogeneous ECL immunoassay studies, performed on larger dendritic complexes containing up to eight ruthenium units, demonstrate that limitations due to the slow diffusion can easily be overcome by means of nanoparticle technology. In this case, the ECL signal is proportional to the number of ruthenium units. Multimetallic systems with several ruthenium centers may, however, undergo nonspecific bonding,to streptavidin-coated particles or to antibodies, thereby increasing the background ECL intensity and lowering the sensitivity of the immunoassay.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This letter proposes the subspace-based blind adaptive channel estimation algorithm for dual-rate quasi-synchronous DS/CDMA systems, which can operate at the low-rate (LR) or high-rate (HR) mode. Simulation results show that the proposed blind adaptive algorithm at the LR mode has a better performance than that at the HR mode, with the cost of an increasing computational complexity.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this letter, we consider beamforming strategies in amplified-and-forward (AF) two-way relay channels, where two terminals and the relay are equipped with multiple antennas. Our aim is to optimize the worse end-to-end signal-to-noise ratio of the two links so that the reliability of both terminals can be guaranteed. We show that the optimization problem can be recast as a generalized fractional programing and be solved by using the Dinkelbach-type procedure combined with semidefinite programming. Simulation results confirm the efficiency of the proposed strategies.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Over the useful life of a LAN, network downtimes will have a negative impact on organizational productivity not included in current Network Topological Design (NTD) problems. We propose a new approach to LAN topological design that includes the impact of these productivity losses into the network design, minimizing not only the CAPEX but also the expected cost of unproductiveness attributable to network downtimes over a certain period of network operation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Diante das transformações pelas quais vem passando a sociedade, cada vez mais complexa, o magistrado necessita estar mais qualificado para julgar as demandas contemporâneas. Assim, torna-se imprescindível que, além de excelente preparo jurídico, o juiz tenha uma visão social e postura ética que o capacitem a solucionar os conflitos sociais que lhes são impostos. Desta forma, há que se ingressar na carreira da magistratura pessoas que possuam amplo conhecimento jurídico, além de conhecimentos extrajurídicos e ainda, possuam equilíbrio psicológico e firmeza ética. Este trabalho analisa a importância de uma formação própria dos magistrados e o papel das Escolas da Magistratura na seleção e formação do magistrado contemporâneo.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A major UK initiative, entitled 'Mapping the Underworld', is seeking to address the serious social, environmental and economic consequences arising from an inability to locate accurately and comprehensively the buried utility service infrastructure without resorting to extensive excavations. Mapping the Underworld aims to develop and prove the efficacy of a multi-sensor device for accurate remote buried utility service detection, location and, where possible, identification. One of the technologies to be incorporated in the device is low-frequency vibro-acoustics, and application of this technique for detecting buried infrastructure is currently being investigated. Here, the potential for making a number of simple point vibration measurements in order to detect shallow-buried objects, in particular plastic pipes, is explored. Point measurements can be made relatively quickly without the need for arrays of surface sensors, which can be expensive, time-consuming to deploy, and sometimes impractical in congested areas. At low frequencies, the ground behaves as a simple single-degree-of-freedom (mass-spring) system with a well-defined resonance, the frequency of which will depend on the density and elastic properties of the soil locally. This resonance will be altered by the presence of a buried object whose properties differ from the surrounding soil. It is this behavior which can be exploited in order to detect the presence of a buried object, provided it is buried at a sufficiently shallow depth. The theoretical background is described and preliminary measurements are made both on a dedicated buried pipe rig and on the ground over a domestic waste pipe. Preliminary findings suggest that, for shallow-buried pipes, a measurement of this kind could be a quick and useful adjunct to more conventional methods of buried pipe detection. © 2012 Elsevier Ltd. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this letter, we propose a new approach to evaluate the bit error rate (BER) of a multirate, multiclass optical fast frequency hopping code-division multiple-access (OFFH-CDMA) system. This proposed approach does not require knowledge of the generated users' code sequences, which makes the system analysis straightforward. Furthermore, the presented formalism can also be successfully applied to most multi-weight multi-length family of codes, as long as the corresponding code parameters are employed.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

La metafora del viaggio è una metafora 'pervasiva', utilizzata quotidianamente e spesso inconsapevolmente. Ma è altrettanto 'automatico' tradurre tali metafore in interpretazione simultanea? Attraverso lo studio di tale tipologia di metafore, tratte dai discorsi pronunciati durante le sessioni plenarie del Parlamento Europeo, e tratti dal corpus EPIC, e durante gli esami finali della Scuola Superiore di Lingue Letterature Traduzione e Interpretazione, se ne osserverà l'uso in italiano, in inglese e in spagnolo. Solo in seguito, sarà possibile prendere in considerazione le rese in interpretazione simultanea degli interpreti del Parlamento Europeo, i 'professionisti', e gli studenti che sostengono gli esami finali, i 'semi-professionisti'. Dalla ricerca sono emerse sostanziali differenze tra la lessicalizzazione delle metafore del viaggio in italiano, inglese e spagnolo che rendono la loro interpretazione in simultanea tutto fuorché semplice e automatica.