Ventilation and outcomes following robotic-assisted abdominal surgery: an international, multicentre observational study

Background: International data on the epidemiology, ventilation practice, and outcomes in patients undergoing abdominal robotic-assisted surgery (RAS) are lacking. The aim of the study was to assess the incidence of postoperative pulmonary complications (PPCs), and to describe ventilator management after abdominal RAS. Methods: This was an international, multicentre, prospective study in 34 centres in nine countries. Patients ≥18 yr of age undergoing abdominal RAS were enrolled between April 2017 and March 2019. The Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT) score was used to stratify for higher risk of PPCs (≥26). The primary outcome was the incidence of PPCs. Secondary endpoints included the preoperative risk for PPCs and ventilator management. Results: Of 1167 subjects screened, 905 abdominal RAS patients were included. Overall, 590 (65.2%) patients were at increased risk for PPCs. Meanwhile, 172 (19%) patients sustained PPCs, which occurred more frequently in 132 (22.4%) patients at increased risk, compared with 40 (12.7%) patients at lower risk of PPCs (absolute risk difference: 12.2% [95% confidence intervals (CI), 6.8–17.6%]; P<0.001). Plateau and driving pressures were higher in patients at increased risk, compared with patients at low risk of PPCs, but no ventilatory variables were independently associated with increased occurrence of PPCs. Development of PPCs was associated with a longer hospital stay. Conclusions: One in five patients developed one or more PPCs (chiefly unplanned oxygen requirement), which was associated with a longer hospital stay. No ventilatory variables were independently associated with PPCs. Clinical trial registration: NCT02989415

Optimal Phase-locked Loop Design With Kalman Predictors For Synchronous Networks

A systematic technique for the optimal design of phase-locked loops for synchronous networks is presented. The method is based on Kalman estimation theory under self-similar random noise processes. This approach is optimal for certain noise models and for linear phase-detectors. The results are then extended in order to maintain the minimum mean-square phase error when the reference signal of a master-slave network is lost.31917192

Spatial and temporal adaptive receiver for DS-CDMA systems

The objective of this paper is to propose a reception scheme to improve the performance of DS-CDMA (Direct Sequence Code Division Multiple Access) systems, compared to conventional direct channel receivers. The technique employs a spatial and temporal adaptive receiver composed of N spatial processors (associated with M antennas) and N Decision Feedback Equalizers (DFE), both of which are trained using a TMDP (Time Multiplexed Dedicated Pilot) sequence. The spatial and temporal receiver associated with TMDP offers considerable benefits when compared to the conventional Rake-Finger receiver. Performance results and details of the functioning of the proposed reception scheme are presented683216226sem informaçã

Multiresolution Model For Image Interpolation With Adaptive Filtering

This paper proposes an image interpolation model based on a multiresolution scheme. The method uses two different known image resolutions to establish a mapping between them. The mapping is then used to extrapolate the unknown resolution to produce an expanded image with increased definition and with a mean square reconstruction error lower than for the conventional methods. In other words, details in a high resolution image are implicitly predicted based only on its low-frequency resolutions. A high subjective quality is obtained due to the similar nature of the mappings, which are constructed by means of an adaptive bidimensional FIR filter.42203220

On the Performance of Generalized Processor Sharing Servers under Long-Range Dependent Traffic

This paper introduces the computation of delay and backlog bounds for a Generalized Processor Sharing (GPS) server under self-similar trac. The trac is supposed to be regulated by the Fractal Leaky Bucket policing mechanism, which is an appropriate regulator for self-similar trac. Results are extended to a network of GPS servers with arbitrary topology, and the stability of those networks is analysed

Solução Weblab para Ensino e Trabalho Colaborativo em Sistemas Digitais

Este trabalho apresenta uma plataforma reconfiguraÌvel aplicada ao ensino e pesquisa colaborativa em laboratoÌrios de sistemas digitais. A plataforma proporciona um ambiente geneÌrico e flexiÌvel em tempo real para praÌtica de laboratoÌrio no modo remoto. A arquitetura proposta possibilita o desenvolvimento de novos experimentos em sistemas digitais, com foco na implementação das funcionalidades que se deseja investigar.Â

Adaptive Beamforming Applied to OFDM Systems

This work proposes an adaptive beamforming scheme applied to time domain, pre-FFT (Fast Fourier Transformation), Orthogonal Frequency-Division Multiplexing (OFDM) systems. This scheme improves the performance and the capacity of OFDM systems, using a supervised adaptive algorithm, with frequency domain multiplexed pilots of the OFDM system as a reference. The simplicity of the proposed structure, as well as the method used to obtain reference signals for the adaptive beamforming, are essential aspects that distinguish this paper from other publications. Details on the operation of the proposed scheme, as well as the performance curves, are presented in this manuscript. The proposal investigated here allows a significant reduction in the guard interval of the OFDM system, thereby increasing its robustness or transmission capacity

Avaliação de Vozes Artificiais: Inteligibilidade, Compreensibilidade e Naturalidade

A evolução dos meios de comunicação tem levado a novas exigências tecnológicas. Hoje em dia, há uma crescente demanda por sistemas sintetizadores de fala de alta qualidade para serem integrados nos mais diversos campos de uso, desde sistemas educativos à telefonia e acessibilidade. Neste contexto de aprimoramento das interações homem-máquina, o presente trabalho avalia a relação entre inteligibilidade, compreensibilidade e naturalidade de vozes sintetizadas pela técnica concatenativa e destaca as características relevantes a serem consideradas tanto para nortear a escolha da voz sintética adequada a uma aplicação, como para auxiliar no aprimoramento dos sintetizadores de fala

Rbf Neural Networks With Centers Assignment Via Karhunen-loeve Transform

A technique for assigning the gaussian centers to a Radial Basis Function Neural Network (RBFNN), based on the Karhunen-Loeve Transform (KLT), is proposed. By applying this technique to time series prediction, a significant performance improvement is obtained in comparison with usual prediction methods that use RBFNNs. For instance, by assigning the KLT scaled eigenvectors to the RBFNN centers yields lower prediction normalized mean squared error (NMSE) and requires less previous known samples than the usual technique that applies the own training set vectors to the centers. The present technique has also shown improved performance when compared with prediction based on RBFNNs that uses the K-means clustering algorithm.21265127