143 resultados para Opticalfiber communication


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In this paper, we investigate an amplify-and-forward (AF) multiple-input multiple-output - spatial division multiplexing (MIMO-SDM) cooperative wireless networks, where each network node is equipped with multiple antennas. In order to deal with the problems of signal combining at the destination and cooperative relay selection, we propose an improved minimum mean square error (MMSE) signal combining scheme for signal recovery at the destination. Additionally, we propose two distributed relay selection algorithms based on the minimum mean squared error (MSE) of the signal estimation for the cases where channel state information (CSI) from the source to the destination is available and unavailable at the candidate nodes. Simulation results demonstrate that the proposed combiner together with the proposed relay selection algorithms achieve higher diversity gain than previous approaches in both flat and frequency-selective fading channels.

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Schools attempting to engage with the families of all learners, including those with culturally and linguistically diverse backgrounds recognize the importance of effective oral and written communication. The aim of this study is to determine if school generated written communication created by an urban school district serving a culturally and linguistically diverse population in the Northeast of the US adhered to the principles of plain English. This exploratory research examined exemplar pieces of written school generated communication, using different forms of linguistic analysis to determine whether the communication contained elements recognized to facilitate or impede the comprehensibility of each piece of communication. Additionally, a text assessment tool which can help schools to analyze the written text communication they send to families was developed and refined.

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In this reported work, the frequency diverse array concept is employed to construct an orthogonal frequency-division multiplexing (OFDM) transmitter that has the capability of securing wireless communication in free space directly in the physical-layer without the need for mathematical encryption. The characteristics of the proposed scheme in terms of its secrecy performance are validated via bit error rate simulation under both high and low signal to noise ratio scenarios using the IEEE 802.11 OFDM physical-layer specification.

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Background
Despite the recognized importance of end-of-life (EOL) communication between patients and physicians, the extent and quality of such communication is lacking.

Objective
We sought to understand patient perspectives on physician behaviours during EOL communication.

Design
In this mixed methods study, we conducted quantitative and qualitative strands and then merged data sets during a mixed methods analysis phase. In the quantitative strand, we used the quality of communication tool (QOC) to measure physician behaviours that predict global rating of satisfaction in EOL communication skills, while in the qualitative strand we conducted semi-structured interviews. During the mixed methods analysis, we compared and contrasted qualitative and quantitative data.

Setting and Participants
Seriously ill inpatients at three tertiary care hospitals in Canada.

Results
We found convergence between qualitative and quantitative strands: patients desire candid information from their physician and a sense of familiarity. The quantitative results (n = 132) suggest a paucity of certain EOL communication behaviours in this seriously ill population with a limited prognosis. The qualitative findings (n = 16) suggest that at times, physicians did not engage in EOL communication despite patient readiness, while sometimes this may represent an appropriate deferral after assessment of a patient's lack of readiness.

Conclusions
Avoidance of certain EOL topics may not always be a failure if it is a result of an assessment of lack of patient readiness. This has implications for future tool development: a measure could be built in to assess whether physician behaviours align with patient readiness.

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N-(aminoalkyl)-4-chloronaphthalene-
1,8-dicarboximides 1, N-
(aminoalkyl)-4-acetamidonaphthalene-
1,8-dicarboximides 3 and N,N'-bis(aminoalkyl)-
perylene-3,4:9,10-tetracarboxydiimides
4 show good fluorescent off ±
on switching in aqueous alcoholic solution
with protons as required for fluorescent
PET sensor design. The excitation
wavelengths lie in the ultraviolet
(lmaxˆ345 and 351 nm) for 1 and 3 and
in the blue-green (lmaxˆ528, 492 and
461 nm) for 4; the emission wavelengths
lie in the violet (lmaxˆ408 nm) for 1, in
the blue (lmaxˆ474 nm) for 3 and in the
yellow-orange (lmaxˆ543 and 583 nm)
for 4. Compound 4b shows substantial
fluorescence enhancement with protons
when immobilized in a poly(vinylchloride)
matrix, provided that 2-nitrophenyloctyl
ether plasticizer and potassium
tetrakis(4-chlorophenyl)borate additive
are present to prevent dye crystallization
and to facilitate proton diffusion
into the membrane, respectively.

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Public, nonprofit and private organisations respond to large-scale disasters domestically and overseas. Critics of these assistance efforts, as well as those involved, often cite poor interorganisational partnering as an obstacle to successful disaster response. Observers frequently call for ‘more’ and ‘better’ partnering. We found important qualitative distinctions existed within partnering behaviours. We identified four different types of interorganisational partnering activities often referred to interchangeably: communication, cooperation, coordination and collaboration—the Four Cs. We derived definitions of the Four Cs from the partnering literature. We then tested them in a case study of the response to the 2010 Haiti earthquake. We suggest that the Four Cs are distinct activities, that organisations are typically strong or weak in one or more for various reasons, and that the four terms represent a continuum of increased interorganisational embeddedness in partnering activities.