FPGA based microserver for high performance real-time computing in Adaptive Optics

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Last results of technological developments for ultra-lightweight, large aperture, deployable mirror for space telescopes

The aim of this work is to describe the latest results of new technological concepts for Large Aperture Telescopes Technology (LATT) using thin deployable lightweight active mirrors. This technology is developed under the European Space Agency (ESA) Technology Research Program and can be exploited in all the applications based on the use of primary mirrors of space telescopes with large aperture, segmented lightweight telescopes with wide Field of View (FOV) and low f/#, and LIDAR telescopes. The reference mission application is a potential future ESA mission, related to a space borne DIAL (Differential Absorption Lidar) instrument operating around 935.5 nm with the goal to measure water vapor profiles in atmosphere. An Optical BreadBoard (OBB) for LATT has been designed for investigating and testing two critical aspects of the technology: 1) control accuracy in the mirror surface shaping. 2) mirror survivability to launch. The aim is to evaluate the effective performances of the long stroke smart-actuators used for the mirror control and to demonstrate the effectiveness and the reliability of the electrostatic locking (EL) system to restraint the thin shell on the mirror backup structure during launch. The paper presents a comprehensive vision of the breadboard focusing on how the requirements have driven the design of the whole system and of the various subsystems. The manufacturing process of the thin shell is also presented

The LATT way towards large active primaries for space telescopes

The Large Aperture Telescope Technology (LATT) goes beyond the current paradigm of future space telescopes, based on a deformable mirror in the pupil relay. Through the LATT project we demonstrated the concept of a low-weight active primary mirror, whose working principle and control strategy benefit from two decades of advances in adaptive optics for ground-based telescopes. We developed a forty centimeter spherical mirror prototype, with an areal density lower than 17 kg/m2, controlled through contactless voice coil actuators with co-located capacitive position sensors. The prototype was subjected to thermo-vacuum, vibration and optical tests, to push its technical readiness toward level 5. In this paper we present the background and the outcomes of the LATT activities under ESA contract (TRP programme), exploring the concept of a lightweight active primary mirror for space telescopes. Active primaries will open the way to very large segmented apertures, actively shaped, which can be lightweight, deployable and accurately phased once in flight

Laboratory demonstration of a primary active mirror for space with the LATT: large aperture telescope technology

The LATT project is an ESA contract under TRP programme to demonstrate the scalability of the technology from ground-based adaptive mirrors to space active primary mirrors. A prototype spherical mirror based on a 40 cm diameter 1 mm thin glass shell with 19 contactless, voice-coil actuators and co-located position sensors have been manufactured and integrated into a final unit with an areal density lower than 20 kg/m2. Laboratory tests demonstrated the controllability with very low power budget and the survival of the fragile glass shell exposed to launch accelerations, thanks to an electrostatic locking mechanism; such achievements pushes the technology readiness level toward 5. With this prototype, the LATT project explored the feasibility of using an active and lightweight primary for space telescopes. The concept is attractive for large segmented telescopes, with surface active control to shape and co-phase them once in flight. In this paper we will describe the findings of the technological advances and the results of the environmental and optical tests

E-ELT M4 adaptive unit final design and construction: a progress report

The E-ELT M4 adaptive unit is a fundamental part of the E-ELT: it provides the facility level adaptive optics correction that compensates the wavefront distortion induced by atmospheric turbulence and partially corrects the structural deformations caused by wind. The unit is based on the contactless, voice-coil technology already successfully deployed on several large adaptive mirrors, like the LBT, Magellan and VLT adaptive secondary mirrors. It features a 2.4m diameter flat mirror, controlled by 5316 actuators and divided in six segments. The reference structure is monolithic and the cophasing between the segments is guaranteed by the contactless embedded metrology. The mirror correction commands are usually transferred as modal amplitudes, that are checked by the M4 controller through a smart real-time algorithm that is capable to handle saturation effects. A large hexapod provides the fine positioning of the unit, while a rotational mechanism allows switching between the two Nasmyth foci. The unit has entered the final design and construction phase in July 2015, after an advanced preliminary design. The final design review is planned for fall 2017; thereafter, the unit will enter the construction and test phase. Acceptance in Europe after full optical calibration is planned for 2022, while the delivery to Cerro Armazones will occur in 2023. Even if the fundamental concept has remained unchanged with respect to the other contactless large deformable mirrors, the specific requirements of the E-ELT unit posed new design challenges that required very peculiar solutions. Therefore, a significant part of the design phase has been focused on the validation of the new aspects, based on analysis, numerical simulations and experimental tests. Several experimental tests have been executed on the Demonstration Prototype, which is the 222 actuators prototype developed in the frame of the advanced preliminary design. We present the main project phases, the current design status and the most relevant results achieved by the validation tests

WOOD-UP

The fundamental vision of the WOOD-UP project was to develop existing wood gasification plants in South Tyrol towards a polygenerative use in order to be able to produce not only energy but also high-quality charcoal (biochar) for the improvement of soil fertility and for climate protection. The project, funded by the European Regional Development Fund ERDF 2014–2020, was implemented by the Free University of Bolzano together with the Laimburg Research Centre. Based on the life cycle analysis (LCA) or scenario analysis of the entire production chain of wood gasification, strengths and weaknesses of the existing systems were identified with regard to their impact on the environment. Thanks to the results obtained, a number of suggestions for improvement could be formulated.; Il miglioramento verso un assetto poligenerativo degli attuali impianti altoatesini di gassificazione della biomassa legnosa, dove oltre all’energia si possa produrre biochar di qualità da impiegare in agricoltura come ammendante con effetti positivi sulla fertilità dei suoli e sulla mitigazione dei cambiamenti climatici è la visione che ha sostenuto il progetto WOOD-UP. Il progetto, finanziato con fondi FESR 2014-2020, ha visto la collaborazione tra la Libera Università di Bolzano e il Centro di Sperimentazione Laimburg. L’analisi del ciclo di vita e di scenario dell’intera filiera di gassificazione ha evidenziato elementi di forza e di debolezza dell’attuale filiera in termini di impatti ambientali e ha permesso di avanzare proposte di miglioramento sulla base dei risultati ottenuti dalla sperimentazione. ; Grundlegende Vision des Projektes WOOD-UP war die Entwicklung der bestehenden Holzvergasungsanlagen in Südtirol hin zu einer polygenerativen Nutzung, um neben Energie auch hochwertige Holzkohle (Biochar) zur Verbesserung der Bodenfruchtbarkeit und zum Klimaschutz erzeugen zu können. Das mit Mitteln aus dem Europäischen Fonds für regionale Entwicklung EFRE 2014–2020 finanzierte Projekt wurde von der Freien Universität Bozen gemeinsam mit dem Versuchszentrum Laimburg umgesetzt. Anhand der Lebenszyklusanalyse (LCA) bzw. der Szenarioanalyse der gesamten Produktionskette der Holzvergasung wurden Stärken und Schwächen der bestehenden Systeme hinsichtlich ihrer Auswirkungen auf die Umwelt aufgezeigt. Dank der erzielten Versuchsergebnisse konnte eine Reihe von Verbesserungsvorschlägen formuliert werden

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Verlustbehaftete und verlustlose Datenkomprimierung fur Daten von Hochenergiephysik Experimenten

This dissertation describes a data compression system optimized for high energy particle detectors. The aim is to reduce the data in the front-end electronics installed in different kind of particle detectors as used for example along the Large Hadron Collider at CERN. The signals collected and digitized from calorimeters, time projection chambers and in general from all detectors with a large number of sensors produce an extensive amount of data, which need to be reduced. Real-time data compression algorithms applied right at the detector front-end is able to reduce the amount of data to be transmitted and stored as early as possible in the data chain. Different lossless and lossy compression methods are analyzed regarding their efficiency in compressing data from particle detectors that produce signals amplified and/or shaped to various waveforms. In addition, the complexity of the algorithms is evaluated to determine their suitability for a real-time hardware implementation. From the analyzed methods, a new developed lossless compression method turned out to be the best suitable one for the implementation in high energy physics applications. The detector data are used to search for rare particle physics phenomena, which makes it crucial that the compression method retains the important information in the data with an appropriate accuracy. Considering the importance of not distorting detector data, a lossless compression method was preferred instead of a lossy method. To go beyond what can be achieved by conventional lossless compression schemes, which are mostly limited by the intrinsic entropy of the underlying data, the proposed compression method makes use of a new scheme where entire vectors of samples are compressed instead of handling the data from the ADCs as individual uncorrelated samples. Our method works by first approximating the incoming vectors, formed by the digitization of the shaped input waveforms from the detector signals, with a set of digitized reference vectors. This is generally known as vector quantization. To prevent information loss the differences between the incoming vector and the best matching reference vector are retained. These differences are then Huffman encoded to obtain the compression. The performance of the compression method was first evaluated by modeling the algorithm in Matlab and using test-data measured with the time projection chamber in the ALICE experiment at CERN. A compression ratio of 50% has been achieved for this test-data (better as the intrinsic entropy of the test-data of 62%). For a demonstration of the functionality of the developed compression method in hardware, a digital IP block was realized and modeled using the hardware description language Verilog. The compression algorithm was optimized for the data from a time projection chamber and tested using a FPGA development board applying the same test-data from the ALICE time projection chamber as used previously in Matlab. The implementation achieved almost the same compression ratio. In this thesis, I show that a data compression of digitized detector data is possible to be realized in the detector front-end electronics very close to the data source by still maintaining the accuracy of the data. The developed and realized lossless compression algorithm achieved a compression ratio of about 50%. The hardware implementation of the algorithm proved its real-time suitability by compressing 10 000 consecutive input signals without introducing dead time. Only an average latency of about 30 clock cycles of 40MHz has to be accepted. The designed data compression IP block is available for an implementation in current and future detector front-end electronics either inside FPGAs or inside full custom ASICs. The compression block requires about 2 700 logic slices inside a Virtex-4 FPGA and around 12 200 gates for an ASIC implementation without taking into account the required memory of 7 kbyte

Respiratory support in patients with severe COVID-19 in the International Severe Acute Respiratory and Emerging Infection (ISARIC) COVID-19 study: a prospective, multinational, observational study

Background: Up to 30% of hospitalised patients with COVID-19 require advanced respiratory support, including high-flow nasal cannulas (HFNC), non-invasive mechanical ventilation (NIV), or invasive mechanical ventilation (IMV). We aimed to describe the clinical characteristics, outcomes and risk factors for failing non-invasive respiratory support in patients treated with severe COVID-19 during the first two years of the pandemic in high-income countries (HICs) and low middle-income countries (LMICs). Methods: This is a multinational, multicentre, prospective cohort study embedded in the ISARIC-WHO COVID-19 Clinical Characterisation Protocol. Patients with laboratory-confirmed SARS-CoV-2 infection who required hospital admission were recruited prospectively. Patients treated with HFNC, NIV, or IMV within the first 24 h of hospital admission were included in this study. Descriptive statistics, random forest, and logistic regression analyses were used to describe clinical characteristics and compare clinical outcomes among patients treated with the different types of advanced respiratory support. Results: A total of 66,565 patients were included in this study. Overall, 82.6% of patients were treated in HIC, and 40.6% were admitted to the hospital during the first pandemic wave. During the first 24 h after hospital admission, patients in HICs were more frequently treated with HFNC (48.0%), followed by NIV (38.6%) and IMV (13.4%). In contrast, patients admitted in lower- and middle-income countries (LMICs) were less frequently treated with HFNC (16.1%) and the majority received IMV (59.1%). The failure rate of non-invasive respiratory support (i.e. HFNC or NIV) was 15.5%, of which 71.2% were from HIC and 28.8% from LMIC. The variables most strongly associated with non-invasive ventilation failure, defined as progression to IMV, were high leukocyte counts at hospital admission (OR [95%CI]; 5.86 [4.83-7.10]), treatment in an LMIC (OR [95%CI]; 2.04 [1.97-2.11]), and tachypnoea at hospital admission (OR [95%CI]; 1.16 [1.14-1.18]). Patients who failed HFNC/NIV had a higher 28-day fatality ratio (OR [95%CI]; 1.27 [1.25-1.30]). Conclusions: In the present international cohort, the most frequently used advanced respiratory support was the HFNC. However, IMV was used more often in LMIC. Higher leucocyte count, tachypnoea, and treatment in LMIC were risk factors for HFNC/NIV failure. HFNC/NIV failure was related to worse clinical outcomes, such as 28-day mortality. Trial registration This is a prospective observational study; therefore, no health care interventions were applied to participants, and trial registration is not applicable