Effects of fibrosis morphology on reentrant ventricular tachycardia inducibility and simulation fidelity in patient-derived models

Myocardial fibrosis detected via delayed-enhanced magnetic resonance imaging (MRI) has been shown to be a strong indicator for ventricular tachycardia (VT) inducibility. However, little is known regarding how inducibility is affected by the details of the fibrosis extent, morphology, and border zone configuration. The objective of this article is to systematically study the arrhythmogenic effects of fibrosis geometry and extent, specifically on VT inducibility and maintenance. We present a set of methods for constructing patient-specific computational models of human ventricles using in vivo MRI data for patients suffering from hypertension, hypercholesterolemia, and chronic myocardial infarction. Additional synthesized models with morphologically varied extents of fibrosis and gray zone (GZ) distribution were derived to study the alterations in the arrhythmia induction and reentry patterns. Detailed electrophysiological simulations demonstrated that (1) VT morphology was highly dependent on the extent of fibrosis, which acts as a structural substrate, (2) reentry tended to be anchored to the fibrosis edges and showed transmural conduction of activations through narrow channels formed within fibrosis, and (3) increasing the extent of GZ within fibrosis tended to destabilize the structural reentry sites and aggravate the VT as compared to fibrotic regions of the same size and shape but with lower or no GZ. The approach and findings represent a significant step toward patient-specific cardiac modeling as a reliable tool for VT prediction and management of the patient. Sensitivities to approximation nuances in the modeling of structural pathology by image-based reconstruction techniques are also implicated.

Offshore Wind Energy System with DC Transmission Discrete Mass: Modeling and Simulation

This paper presents an integrated model for an offshore wind energy system taking into consideration a contribution for the marine wave and wind speed with perturbations influences on the power quality of current injected into the electric grid. The paper deals with the simulation of one floating offshore wind turbine equipped with a PMSG and a two-level converter connected to an onshore electric grid. The use of discrete mass modeling is accessed in order to reveal by computing the THD on how the perturbations of the captured energy are attenuated at the electric grid injection point. Two torque actions are considered for the three-mass modeling, the aerodynamic on the flexible part and on the rigid part of the blades. Also, a torque due to the influence of marine waves in deep water is considered. PI fractional-order control supports the control strategy. A comparison between the drive train models is presented.

Liquid Mixtures Involving Hydrogenated and Fluorinated Alcohols: Thermodynamics, Spectroscopy, and Simulation

This article reports a combined thermodynamic, spectroscopic, and computational study on the interactions and structure of binary mixtures of hydrogenated and fluorinated substances that simultaneously interact through strong hydrogen bonding. Four binary mixtures of hydrogenated and fluorinated alcohols have been studied, namely, (ethanol + 2,2,2-trifluoroethanol (TFE)), (ethanol + 2,2,3,3,4,4,4-heptafluoro-1-butanol), (1-butanol (BuOH) + TFE), and (BuOH + 2,2,3,3,4,4,4-heptafluoro-1-butanol). Excess molar volumes and vibrational spectra of all four binary mixtures have been measured as a function of composition at 298 K, and molecular dynamics simulations have been performed. The systems display a complex behavior when compared with mixtures of hydrogenated alcohols and mixtures of alkanes and perfluoroalkanes. The combined analysis of the results from different approaches indicates that this results from a balance between preferential hydrogen bonding between the hydrogenated and fluorinated alcohols and the unfavorable dispersion forces between the hydrogenated and fluorinated chains. As the chain length increases, the contribution of dispersion increases and overcomes the contribution of H-bonds. In terms of the liquid structure, the simulations suggest the possibility of segregation between the hydrogenated and fluorinated segments, a hypothesis corroborated by the spectroscopic results. Furthermore, a quantitative analysis of the infrared spectra reveals that the presence of fluorinated groups induces conformational changes in the hydrogenated chains from the usually preferred all-trans to more globular arrangements involving gauche conformations. Conformational rearrangements at the CCOH dihedral angle upon mixing are also disclosed by the spectra.

Offshore Wind Energy Conversion System Connected to the Electric Grid: Modeling and Simulation

This paper is on modeling and simulation for an offshore wind system equipped with a semi-submersible floating platform, a wind turbine, a permanent magnet synchronous generator, a multiple point clamped four level or five level full-power converter, a submarine cable and a second order filter. The drive train is modeled by three mass model considering the resistant stiffness torque, structure and tower in deep water due to the moving surface elevation. The system control uses PWM by space vector modulation associated with sliding mode and proportional integral controllers. The electric energy is injected into the electric grid either by an alternated current link or by a direct current link. The model is intend to be a useful tool for unveil the behavior and performance of the offshore wind system, especially for the multiple point clamped full-power converter, under normal operation or under malfunctions.

Measurement and simulation of conducted disturbances on DC power grids of a HVDC system with an active DC/DC converter

With the increasing of the distributed generation, DC microgrids have become more and more common in the electrical network. To connect devices in a microgrid, converter are necessary, but they are also source of disturbances due to their functioning. In this thesis, measurement and simulation of conducted emissions, within the frequency range 2-150kHz, of a DC/DC buck converter are studied.

Measurement of CP violation with $B^0_{(s)} \to h^+ h^{\prime-}$ decays, $|V_{cb}|$ with $B^0_{s}\to D^{(*)-}_s \mu^+ \nu_\mu$ decays, and simulation and characterisation of the LHCb Upgrade II ECAL

The time-dependent CP asymmetries of the $B^0\to\pi^+\pi^-$ and $B^0_s\toK^+K^-$ decays and the time-integrated CP asymmetries of the $B^0\toK^+\pi^-$ and $B^0_s\to\pi^+K^-$ decays are measured, using the $p-p$ collision data collected with the LHCb detector and corresponding to the full Run2. The results are compatible with previous determinations of these quantities from LHCb, except for the CP-violation parameters of the $B^0_s\to K^+K^-$ decays, that show a discrepancy exceeding 3 standard deviations between different data-taking periods. The investigations being conducted to understand the discrepancy are documented. The measurement of the CKM matrix element $|V_{cb}|$ using $B^0_{s}\to D^{(*)-}_s\mu^+ \nu_\mu$ is also reported, using the $p-p$ collision data collected with the LHCb detector and corresponding to the full Run1. The measurement leads to $|V_{cb}| = (41.4\pm0.6\pm0.9\pm1.2)\times 10^{-3}$, where the first uncertainty is statistical, the second is systematic, and the third is due to external inputs. This measurement is compatible with the world averages and constitutes the first measurement of $|V_{cb}|$ at a hadron collider and the absolute first one with decays of the $B^0_s$ meson. The analysis also provides the very first measurements of the branching ratio and form factors parameters of the signal decay modes. The study of the characteristics ruling the response of an electromagnetic calorimeter (ECAL) to profitably operate in the high luminosity regime foreseen for the Upgrade2 of LHCb is reported in the final part of this Thesis. A fast and flexible simulation framework is developed to this purpose. Physics performance of different configurations of the ECAL are evaluated using samples of fully simulated $B^0\to \pi^+\pi^-\pi^0$ and $B^0\to K^{*0}e^+e^-$ decays. The results are used to guide the development of the future ECAL and are reported in the Framework Technical Design Report of the LHCb Upgrade2 detector.

Uma abordagem evolucionária para o planejamento online de rotas para múltiplos robôs móveis em ambiente multiagente

O problema de planejamento de rotas de robôs móveis consiste em determinar a melhor rota para um robô, em um ambiente estático e/ou dinâmico, que seja capaz de deslocá-lo de um ponto inicial até e um ponto final, também em conhecido como estado objetivo. O presente trabalho emprega o uso de uma abordagem baseada em Algoritmos Genéticos para o planejamento de rotas de múltiplos robôs em um ambiente complexo composto por obstáculos fixos e obstáculos moveis. Através da implementação do modelo no software do NetLogo, uma ferramenta utilizada em simulações de aplicações multiagentes, possibilitou-se a modelagem de robôs e obstáculos presentes no ambiente como agentes interativos, viabilizando assim o desenvolvimento de processos de detecção e desvio de obstáculos. A abordagem empregada busca pela melhor rota para robôs e apresenta um modelo composto pelos operadores básicos de reprodução e mutação, acrescido de um novo operador duplo de refinamento capaz de aperfeiçoar as melhores soluções encontradas através da eliminação de movimentos inúteis. Além disso, o calculo da rota de cada robô adota um método de geração de subtrechos, ou seja, não calcula apenas uma unica rota que conecta os pontos inicial e final do cenário, mas sim várias pequenas subrotas que conectadas formam um caminho único capaz de levar o robô ao estado objetivo. Neste trabalho foram desenvolvidos dois cenários, para avaliação da sua escalabilidade: o primeiro consiste em um cenário simples composto apenas por um robô, um obstáculo movel e alguns obstáculos fixos; já o segundo, apresenta um cenário mais robusto, mais amplo, composto por múltiplos robôs e diversos obstáculos fixos e moveis. Ao final, testes de desempenho comparativos foram efetuados entre a abordagem baseada em Algoritmos Genéticos e o Algoritmo A*. Como critério de comparação foi utilizado o tamanho das rotas obtidas nas vinte simulações executadas em cada abordagem. A analise dos resultados foi especificada através do Teste t de Student.

Conception mécanique d'un chien robot : GIPO

La conceció de GIPO té com a areferència el gos AIBO, desenvolupat per Sony. L'estudi per a la seva realització comprèn el desenvolupament de la part tecnològica. S'assumeix que la cinemàtica d'AIBO ha estat àmpliament provada i que és òptima.

Sistema de manteniment de l'equilibri per a un robot bípede

Dins el departament d’Electrònica, Informàtica i Automàtica de la Universitat de Girona s’handissenyat i construït dues plataformes bípedes per a l’ús docent. La mésevolucionada d’elles, finalitzada l’any 1999, està composada per dues cames d’alumini ambtres actuadors lineals cada una, simulant la funció del turmell, del genoll i del maluc. Els objectius que es pretenen aconseguir amb aquest projecte són molt concrets i tots ellsestan destinats a millorar el funcionament del robot bípede. Aquests objectius són: (1)dissenyar dos graus de llibertat lineals en forma de pla XY per moure el pes que convinguiper assegurar l’equilibri durant el moviment de la plataforma bípede, (2) dissenyar una placaamb una FPGA que generi senyals PWM pels vuit motors disponibles, que llegeixi els dosencoders dels motors del pla XY i que es comuniqui amb un PC equipat amb una tarjad’adquisició de dades específica, (3) dissenyar una placa de potència adequada pel controldels motors, (4) finalment realitzar un programa per comprovar el correcte funcionament deles plaques, dels actuadors i dels sensors utilitzats en la plataforma bípede

Integració de la posició GPS per fer el control del moviment d'un robot

L’objectiu d’aquest treball és fer un estudi dels diferents tipus de sistemes de posicionament global que hi ha en el mercat, elegir un mòdul receptor assequible per poder analitzar-lo i veure si disposa de les característiques adequades per integrar-lo en un robot autònom d’exploració del projecte Sant Bernardo. S’hauran de fer les anàlisis de la precisió del mòdul en les diferents direccions cardinals, es a dir Nord, Sud, Est, Oest i altura i veure la diferència d’error que hi ha en cada una, veure si la precisió varia molt en diferents situacions, com en cel obert, en sotabosc, costat i interior edificis. A més a més s’haurà de mirar la repetibilitat, la diferencia d’error amb diferentnombre de satèl•lits connectats i si disposa de suficient velocitat de processat per a podar corregir la posició del robot en moviment. Un cop analitzades les característiques del mòdul receptor elegit, es decidirà si aquest ésadequat per fer les correccions de posició del robot, o s’haurà d’adquirir un mòdul de característiques superiors i per tant molt més car per a dura a terme adequadament la correcció de la posició

Conception mécanique d'un chien robot : GIPO

La conceció de GIPO té com a areferència el gos AIBO, desenvolupat per Sony. L'estudi per a la seva realització comprèn el desenvolupament de la part tecnològica. S'assumeix que la cinemàtica d'AIBO ha estat àmpliament provada i que és òptima.

Sistema de manteniment de l'equilibri per a un robot bípede

Dins el departament d’Electrònica, Informàtica i Automàtica de la Universitat de Girona s’han dissenyat i construït dues plataformes bípedes per a l’ús docent. La més evolucionada d’elles, finalitzada l’any 1999, està composada per dues cames d’alumini amb tres actuadors lineals cada una, simulant la funció del turmell, del genoll i del maluc. Els objectius que es pretenen aconseguir amb aquest projecte són molt concrets i tots ells estan destinats a millorar el funcionament del robot bípede. Aquests objectius són: (1) dissenyar dos graus de llibertat lineals en forma de pla XY per moure el pes que convingui per assegurar l’equilibri durant el moviment de la plataforma bípede, (2) dissenyar una placa amb una FPGA que generi senyals PWM pels vuit motors disponibles, que llegeixi els dos encoders dels motors del pla XY i que es comuniqui amb un PC equipat amb una tarja d’adquisició de dades específica, (3) dissenyar una placa de potència adequada pel control dels motors, (4) finalment realitzar un programa per comprovar el correcte funcionament de les plaques, dels actuadors i dels sensors utilitzats en la plataforma bípede