Energy efficiency of mmWave massive MIMO precoding with low-resolution DACs

With the congestion of the sub-6 GHz spectrum, the interest in massive multiple-input multiple-output (MIMO) systems operating on millimeter wave spectrum grows. In order to reduce the power consumption of such massive MIMO systems, hybrid analog/digital transceivers and application of low-resolution digital-to-analog/analog-to-digital converters have been recently proposed. In this work, we investigate the energy efficiency of quantized hybrid transmitters equipped with a fully/partially-connected phase-shifting network composed of active/passive phase-shifters and compare it to that of quantized digital precoders. We introduce a quantized single-user MIMO system model based on an additive quantization noise approximation considering realistic power consumption and loss models to evaluate the spectral and energy efficiencies of the transmit precoding methods. Simulation results show that partially-connected hybrid precoders can be more energy-efficient compared to digital precoders, while fully-connected hybrid precoders exhibit poor energy efficiency in general. Also, the topology of phase-shifting components offers an energy-spectral efficiency trade-off: active phase-shifters provide higher data rates, while passive phase-shifters maintain better energy efficiency.Comment: Published in IEEE Journal of Selected Topics in Signal Processin

Counterexample Guided Inductive Optimization Applied to Mobile Robots Path Planning (Extended Version)

We describe and evaluate a novel optimization-based off-line path planning algorithm for mobile robots based on the Counterexample-Guided Inductive Optimization (CEGIO) technique. CEGIO iteratively employs counterexamples generated from Boolean Satisfiability (SAT) and Satisfiability Modulo Theories (SMT) solvers, in order to guide the optimization process and to ensure global optimization. This paper marks the first application of CEGIO for planning mobile robot path. In particular, CEGIO has been successfully applied to obtain optimal two-dimensional paths for autonomous mobile robots using off-the-shelf SAT and SMT solvers.Comment: 7 pages, 14rd Latin American Robotics Symposium (LARS'2017

Frontiers in the expansion of bioproducts

[no abstract available

Severidade da queima das folhas e quantificação de fenóis solúveis totais e lagnina solúveil em cultivares de cenoura.

O objetivo deste trabalho foi avaliar a severidade da doença em cultivares tradicionais de cenoura (Brasília, BRS Planalto, Juliana, BRS Esplanada, Branca Lunar, Amarela Solar e Londrina) em campo, bem com quantificar as concentrações de fenóis solúveis totais e lignina solúvel nas folhas.Resumo 1265

Citronella essential oil in the control and activation of coffee plants defense response against rust and brown eye spot.

Objetivou-se avaliar o óleo essencial de citronela no controle da ferrugem e cercosporiose e na ativação de respostas de defesa em cafeeiro

Frontiers in the Expansion of Bioproducts

[no abstract available

Bird flu outbreak amidst COVID-19 pandemic in South Africa:Efforts and challenges at hand

Over the months of April and May 2021, South Africa has witnessed several outbreaks of highly infective avian influenza (H5N1) in different poultry farms. This came as a shock to a country that was already battling with the deadly COVID‐19 pandemic. The emergence of the virus has spurred import bans and massive culls in the poultry business. Local experts have also called for a restriction on the movement of people and cars in and out of their chicken farms. Employees have also been encouraged to shower in the mornings when they arrive at the farms and wear fresh clothes, as the flu spreads very quickly. In a country that is already facing the economic implications of the COVID‐19, this has the potential to cause a significant dent in the economy, as well as severely impact people's day‐to‐day life. Bird flu—also called avian influenza—is a viral infection that can infect not only birds but also humans and other animals. The threat of a new influenza pandemic has prompted countries to draft national strategic preparedness plans to prevent, contain and mitigate the next human influenza pandemic. This paper describes the South African burden, current efforts, and preparedness against the avian influenza virus