Local weak observability conditions of sensorless AC drives

Alternating current (AC) electrical drive control without mechanical sensors is an active research topic. This paper studies the observability of both induction machine and synchronous machine sensorless drives. Observer-based sensorless techniques are known for their deteriorated performance in some operating conditions. An observability analysis of the machines helps understanding (and improving) the observer's behavior in the aforementioned conditions.Comment: arXiv admin note: text overlap with arXiv:1512.0366

Observability analysis of sensorless synchronous machine drives

This paper studies the local observability of synchronous machines using a unified approach. Recently, motion sensorless control of electrical drives has gained high interest. The main challenge for such a technology is the poor performance in some operation conditions. One interesting theory that helps understanding the origin of this problem is the observability analysis of nonlinear systems. In this paper, the observability of the wound-rotor synchronous machine is studied. The results are extended to other synchronous machines, adopting a unified analysis. Furthermore, a high-frequency injection-based technique is proposed to enhance the sensorless operation of the wound-rotor synchronous machine at standstill

Discussion on "AC Drive Observability Analysis"

In the paper by Vaclavek et al. (IEEE Trans. Ind. Electron., vol. 60, no. 8, pp. 3047-3059, Aug. 2013), the local observability of both induction machine and permanent-magnet synchronous machine (PMSM) under motion-sensorless operation is studied. In this letter, the "slowly varying" speed assumption is discussed, and the PMSM observability condition at standstill is revisited

Influence of PWM methods in semiconductor losses of 15kVA three-phase SiC inverter for aircraft applications

In near future, modern aircrafts will be more electrical, having more power converters in different applications. Inverters is one of the most common applications, which are used in actuators, cabin pressurization, among others. In order to significantly reduce weight, size and losses of these converters, disruptive technology such as Wide Bandgap components (SiC and GaN transistors) should be used. In this paper, we study the influence of SiC components in a 540V/15kVA inverter for motor driving applications. The approach proposed here starts by the dynamic characterization of SiC modules with the aim of obtaining accurate switching energies in order to precisely calculate semiconductor losses in three-phase inverters. Then, precise conduction and switching loss calculation is developed to verify the influence of PWM methods on losses of this converter. A generic 15kVA inverter setup is built. Experimental results in this setup confirm the characterization and loss calculation and shows the best PWM methods for specific aircraft applications

High-Precision Radiosurgical Dose Delivery by Interlaced Microbeam Arrays of High-Flux Low-Energy Synchrotron X-Rays

Microbeam Radiation Therapy (MRT) is a preclinical form of radiosurgery dedicated to brain tumor treatment. It uses micrometer-wide synchrotron-generated X-ray beams on the basis of spatial beam fractionation. Due to the radioresistance of normal brain vasculature to MRT, a continuous blood supply can be maintained which would in part explain the surprising tolerance of normal tissues to very high radiation doses (hundreds of Gy). Based on this well described normal tissue sparing effect of microplanar beams, we developed a new irradiation geometry which allows the delivery of a high uniform dose deposition at a given brain target whereas surrounding normal tissues are irradiated by well tolerated parallel microbeams only. Normal rat brains were exposed to 4 focally interlaced arrays of 10 microplanar beams (52 µm wide, spaced 200 µm on-center, 50 to 350 keV in energy range), targeted from 4 different ports, with a peak entrance dose of 200Gy each, to deliver an homogenous dose to a target volume of 7 mm3 in the caudate nucleus. Magnetic resonance imaging follow-up of rats showed a highly localized increase in blood vessel permeability, starting 1 week after irradiation. Contrast agent diffusion was confined to the target volume and was still observed 1 month after irradiation, along with histopathological changes, including damaged blood vessels. No changes in vessel permeability were detected in the normal brain tissue surrounding the target. The interlacing radiation-induced reduction of spontaneous seizures of epileptic rats illustrated the potential pre-clinical applications of this new irradiation geometry. Finally, Monte Carlo simulations performed on a human-sized head phantom suggested that synchrotron photons can be used for human radiosurgical applications. Our data show that interlaced microbeam irradiation allows a high homogeneous dose deposition in a brain target and leads to a confined tissue necrosis while sparing surrounding tissues. The use of synchrotron-generated X-rays enables delivery of high doses for destruction of small focal regions in human brains, with sharper dose fall-offs than those described in any other conventional radiation therapy

Diversité des agricultures – le cas des filières céréales, oléagineux et légumineuses à graines

L’objectif de cet article est de décrire, sans être exhaustif, la diversité des agricultures en mobilisant des exemples au niveau du système technique et des pratiques culturales, pour la France métropolitaine et pour trois filières : les céréales, les oléagineux et les légumineuses à graines. L’analyse de la diversité des agricultures montre que des voies de diversification des systèmes techniques et des pratiques culturales existent, mais que celles-ci sont fortement dépendantes de la diversité des voies de valorisation dans les filières. Au sein de ces dispositifs de valorisation, hormis quelques dispositifs spécifiques, les recommandations sur les pratiques sont suffisamment vastes pour permettre une diversité de systèmes de culture et de production, dès lors que les critères technologiques d’accès à la filière sont atteints. Il convient alors de s’interroger sur le poids de ces critères technologiques sur les choix techniques des agriculteurs. Il apparait également nécessaire de questionner la valeur donnée à la diversité par les différents acteurs des filières, de l’agriculteur au consommateur, en évaluant notamment la performance économique des systèmes agricoles les plus diversifiés ainsi que les leviers pour augmenter les performances d’une agriculture diversifiée. Il s’agit d’élargir le socle de connaissances sur lequel les acteurs pourront concevoir eux-mêmes de nouvelles formes de diversité et d’ouvrir le débat avec les acteurs des filières sur la préservation des formes de diversité des agricultures comme potentiel de résilience

Objective review of de novo stand-alone error correction methods for NGS data

[EN] The sequencing market has increased steadily over the last few years, with different approaches to read DNA information prone to different types of errors. Multiple studies demonstrated the impact of sequencing errors on different applications of next-generation sequencing (NGS), making error correction a fundamental initial step. Different methods in the literature use different approaches and fit different types of problems. We analyzed 50 methods divided into five main approaches (k-spectrum, suffix arrays, multiple-sequence alignment, read clustering, and probabilistic models). They are not published as a part of a suite (stand-alone), and target raw, unprocessed data without an existing reference genome (de novo). These correctors handle one or more sequencing technologies using the same or different approaches. They face general challenges (sometimes with specific traits for specific technologies) such as repetitive regions, uncalled bases, and ploidy. Even assessing their performance is a challenge in itself because of the approach taken by various authors, the unknown factor (de novo), and the behavior of the third-party tools employed in the benchmarks. This study aims to help the researcher in the field to advance the field of error correction, the educator to have a brief but comprehensive companion, and the bioinformatician to choose the right tool for the right job. © 2016 John Wiley & Sons, LtdWe want to thank our colleague Eloy Romero Alcale who has provided valuable advice regarding the structure of the document. This work was supported by Generalitat Valenciana [GRISOLIA/2013/013 to A.A.].Alic, AS.; Ruzafa, D.; Dopazo, J.; Blanquer Espert, I. (2016). Objective review of de novo stand-alone error correction methods for NGS data. Wiley Interdisciplinary Reviews: Computational Molecular Science. 6(2):111-146. https://doi.org/10.1002/wcms.1239S1111466

Vaccine breakthrough hypoxemic COVID-19 pneumonia in patients with auto-Abs neutralizing type I IFNs

Life-threatening `breakthrough' cases of critical COVID-19 are attributed to poor or waning antibody response to the SARS- CoV-2 vaccine in individuals already at risk. Pre-existing autoantibodies (auto-Abs) neutralizing type I IFNs underlie at least 15% of critical COVID-19 pneumonia cases in unvaccinated individuals; however, their contribution to hypoxemic breakthrough cases in vaccinated people remains unknown. Here, we studied a cohort of 48 individuals ( age 20-86 years) who received 2 doses of an mRNA vaccine and developed a breakthrough infection with hypoxemic COVID-19 pneumonia 2 weeks to 4 months later. Antibody levels to the vaccine, neutralization of the virus, and auto- Abs to type I IFNs were measured in the plasma. Forty-two individuals had no known deficiency of B cell immunity and a normal antibody response to the vaccine. Among them, ten (24%) had auto-Abs neutralizing type I IFNs (aged 43-86 years). Eight of these ten patients had auto-Abs neutralizing both IFN-a2 and IFN-., while two neutralized IFN-omega only. No patient neutralized IFN-ss. Seven neutralized 10 ng/mL of type I IFNs, and three 100 pg/mL only. Seven patients neutralized SARS-CoV-2 D614G and the Delta variant (B.1.617.2) efficiently, while one patient neutralized Delta slightly less efficiently. Two of the three patients neutralizing only 100 pg/mL of type I IFNs neutralized both D61G and Delta less efficiently. Despite two mRNA vaccine inoculations and the presence of circulating antibodies capable of neutralizing SARS-CoV-2, auto-Abs neutralizing type I IFNs may underlie a significant proportion of hypoxemic COVID-19 pneumonia cases, highlighting the importance of this particularly vulnerable population

Search for the direct production of charginos and neutralinos in final states with tau leptons in √s=13 TeV collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with at least two hadronically decaying tau leptons is presented. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of 36.1 fb−1, recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 13TeV.Nosignificant deviation from the expected Standard Model background is observed. Limits are derived in scenarios of ˜χ+1 ˜χ−1 pair production and of ˜χ±1 ˜χ02 and ˜χ+1 ˜χ−1 production in simplified models where the neutralinos and charginos decay solely via intermediate left-handed staus and tau sneutrinos, and the mass of the ˜ τL state is set to be halfway between the masses of the ˜χ±1 and the ˜χ01. Chargino masses up to 630 GeV are excluded at 95% confidence level in the scenario of direct production of ˜χ+1 ˜χ−1 for a massless ˜χ01. Common ˜χ±1 and ˜χ02 masses up to 760 GeV are excluded in the case of production of ˜χ±1 ˜χ02 and ˜χ+1 ˜χ−1 assuming a massless ˜χ01. Exclusion limits for additional benchmark scenarios with large and small mass-splitting between the ˜χ±1 and the ˜χ01 are also studied by varying the ˜ τL mass between the masses of the ˜χ±1 and the ˜χ01