A systematic approach to determining the minimum sampling rate for real-time spacecraft control

To be published in the proceedings of the 27th AAS/AIAA Spaceflight Mechanics Meeting, San Antonio, TX, Feb. 6-9, 2017Typical controller design and analysis methods utilize techniques for continuous- time systems. However, digital computation is the favored approach to implement- ing the resulting controllers. This leads to the natural question of choosing an ap- propriate sampling rate for the controller. There exist several ”Rules of Thumbs” for choosing a sample rate derived from primarily frequency domain properties of the system. A metric to estimate the sample rate based on the system properties rooted from first principles is developed. It is then validated via several case stud- ies using representative mechanical systems, actuators, and controllers. Lastly, the paper concludes with a discussion on the applications of this metric

Recovering grand urbanism : ecological landscape, wetlands and phytodepuration in Magok Park, Seoul

The right to clean water is a vital resource in consolidated emerging urban economies. Alternative fresh water resources and public wastewater management represent one of the most valuable services. However fresh water requires an adequate and advanced depuration technique: the Integrated System of Phytodepuration (ISP). The expansion of mega-cities worldwide has generated many derelict voids. The proliferation of highly polluted brownfields is a constant characteristic, which is likely to continue and increase in future. If left to fall in to neglectfulness and urban inertia, these spaces will have a detrimental effecton local neighborhoods in terms of social health, wellbeing, local economies and environmental qualities. The development of urban parks in urban voids has been generically implemented without environmental and ecological recovery strategies. Waterscape is not just an aesthetic feature but also a decisive element in the production of the space. The construction of manmade wetlands(bio-remediators) offers landscape, ecological and environmental qualities that heal polluted environments. This study explores innovative waterscape systems in the brownfield of Magok basin, Seoul: http://issuu.com/cristiansuau/docs/urban_park_seoul. The landscape design scheme reproduces natural self-depurative processes in a controllable environment by taking into account both the strategic location and necessity for ecological remediation. Innovative water-terracing systems (eco-formations) are proposed as water phytodepuration treatment. It consists of offsetting contaminants on wastewater surface, through the establishing of native plants and aeration. These terraces are dwelled by aquatic plants (macrophytes), which reproduce the natural purification processes frequently inhumid climates. The development of this “artificial wetland scheme” is based on octagonal eco-formations. They aim to create a social catalyst as well as a healthy environment, providing recreation and amenities combined with the gray water biological and distillation treatments

Analgesia induced by the epigenetic drug, L-acetylcarnitine, outlasts the end of treatment in mouse models of chronic inflammatory and neuropathic pain

Background: L-acetylcarnitine, a drug marketed for the treatment of chronic pain, causes analgesia by epigenetically up-regulating type-2 metabotropic glutamate (mGlu2) receptors in the spinal cord. Because the epigenetic mechanisms are typically long-lasting, we hypothesized that analgesia could outlast the duration of L-acetylcarnitine treatment in models of inflammatory and neuropathic pain. Results: A seven-day treatment with L-acetylcarnitine ( 100 mg/kg, once a day, i.p.) produced an antiallodynic effect in the complete Freund adjuvant mouse model of chronic inflammatory pain. L-Acetylcarnitine-induced analgesia persisted for at least 14 days after drug withdrawal. In contrast, the analgesic effect of pregabalin, amitryptiline, ceftriaxone, and N-acetylcysteine disappeared seven days after drug withdrawal. L-acetylcarnitine treatment enhanced mGlu2/3 receptor protein levels in the dorsal region of the spinal cord. This effect also persisted for two weeks after drug withdrawal and was associated with increased levels of acetylated histone H3 bound to the Grm2 gene promoter in the dorsal root ganglia. A long-lasting analgesic effect of L-acetylcarnitine was also observed in mice subjected to chronic constriction injury of the sciatic nerve. In these animals, a 14-day treatment with pregabalin, amitryptiline, tramadol, or L-acetylcarnitine produced a significant antiallodynic effect, with pregabalin displaying the greatest efficacy. In mice treated with pregabalin, tramadol or L-acetylcarnitine the analgesic effect was still visible 15 days after the end of drug treatment. However, only in mice treated with L-acetylcarnitine analgesia persisted 37 days after drug withdrawal. This effect was associated with an increase in mGlu2/3 receptor protein levels in the dorsal horns of the spinal cord. Conclusions: Our findings suggest that L-acetylcarnitine has the unique property to cause a long-lasting analgesic effect that might reduce relapses in patients suffering from chronic pain

Autonomous Capture of a Resident Space Object by a Spacecraft with a Robotic Manipulator: Analysis, Simulation and Experiments

AIAA/AAS Astrodynamics Specialist Conference, Long Beach, CA. The article of record may be found at:http://arc.aiaa.org | DOI: 10.2514/6.2016-5269This paper describes a set of laboratory-based experiments, which demonstrate the autonomous capture of a non-moving resident space object by a spacecraft equipped with a single robotic manipulator. An air bearing test bed is used to simulate weightlessness and frictionless maneuvering on a plane. The chaser is composed by a floating spacecraft simulator carrying a kinematically redundant four-link serial manipulator. The manipulator mass is similar to the mass of its base-spacecraft, resulting in an unusually large dynamic coupling. Emphasis is given to the guidance and control, demonstrating floating, flying and rotation-flying coordinated control strategies. A resolved-motion-rate controller regulates the manipulator joint velocities. The relative navigation problem, solved by the test bed metrology system, has been left outside the scope of this effort. The presented experiments increase the number of space robotics experimental evaluations conducted in dynamically representative environments

mGlu1 Receptors Monopolize the Synaptic Control of Cerebellar Purkinje Cells by Epigenetically Down-Regulating mGlu5 Receptors

In cerebellar Purkinje cells (PCs) type-1 metabotropic glutamate (mGlu1) receptors play a key role in motor learning and drive the refinement of synaptic innervation during postnatal development. The cognate mGlu5 receptor is absent in mature PCs and shows low expression levels in the adult cerebellar cortex. Here we found that mGlu5 receptors were heavily expressed by PCs in the early postnatal life, when mGlu1α receptors were barely detectable. The developmental decline of mGlu5 receptors coincided with the appearance of mGlu1α receptors in PCs, and both processes were associated with specular changes in CpG methylation in the corresponding gene promoters. It was the mGlu1 receptor that drove the elimination of mGlu5 receptors from PCs, as shown by data obtained with conditional mGlu1α receptor knockout mice and with targeted pharmacological treatments during critical developmental time windows. The suppressing activity of mGlu1 receptors on mGlu5 receptor was maintained in mature PCs, suggesting that expression of mGlu1α and mGlu5 receptors is mutually exclusive in PCs. These findings add complexity to the the finely tuned mechanisms that regulate PC biology during development and in the adult life and lay the groundwork for an in-depth analysis of the role played by mGlu5 receptors in PC maturation

Early initiation of a replication origin tethered at the nuclear periphery

Peer reviewedPublisher PD

Bonaviri inedito

Book Reviews / Recension

Design and Development of a Verification Automation Tool for Aerospace Software

LAUREA MAGISTRALEQuesto studio esplora l’implementazione e l’adozione del tool "Europa", progettato per automatizzare il processo di verifica per un sistema FADEC (Full Authority Digital Engine Control). Il processo di verifica era inizialmente manuale, quindi inefficiente e soggetto a errori umani. Adattando un semi-lavorato prodotto internamente, il tool Europa è stato implementato per affrontare questi problemi, portando a miglioramenti nell’efficienza del processo e nella qualità dei risultati dei test. L’automazione fornita dal tool Europa offre maggiore precisione, ripetibilità e risultati più rapidi rispetto ai processi manuali. Standardizza la procedura di verifica ed elimina l’interpretabilità. Inoltre, il tool genera la documentazione richiesta e la tracciabilità dei requisiti, garantendo la conformità alle linee guida di certificazione aeronautica. Il tool Europa lascia spazio a ulteriori miglioramenti, come l’introduzione di controlli basati sull’avvenimento di un evento piuttosto che basati sul tempo. Allo stesso tempo, la struttura flessibile consente l’implementazione di algoritmi complessi che potrebbero aiutare nell’analisi della traiettoria di volo. Il rapporto esplora anche il potenziale utilizzo dell’intelligenza artificiale (AI) per migliorare l’automazione. Anche se l’intelligenza artificiale apporta enormi vantaggi in aeronautica, potrebbe essere difficile introdurla in sistemi critici per la sicurezza come il FADEC a causa dei rischi intrinsechi. La conclusione raggiunta è che in questo tipo di sistema l’intelligenza artificiale potrebbe essere presto utilizzata per supportare l’attività umana, ma potrebbe essere necessaria una certa mitigazione del rischio. In conclusione, lo strumento Europa costituisce una preziosa aggiunta al processo di verifica, offrendo adattabilità e spazio per futuri miglioramenti. Ha il potenziale per essere applicato ad altri progetti all’interno dell’azienda, contribuendo a migliorare la qualità del prodotto e ridurre gli errori degli utenti.This report explores the implementation and adoption of the Europa tool, designed to automate the verification process for a Full Authority Digital Engine Control (FADEC) system. The verification process was manual, hence inefficient and prone to human error. By adapting an in-house semi-developed framework, the Europa tool was implemented to address these issues, leading to improvements in process efficiency and the quality of test results. The automation provided by the Europa tool offers enhanced accuracy, repeatability, and faster outcomes compared to manual processes. It standardizes the verification procedure and removes interpretability. Additionally, the tool generates the required documentation and requirements traceability, ensuring compliance with aeronautical certification guidelines. The Europa tool leaves space for further improvements, like introducing event-based checks. At the same time, the flexible structure allows the implementation of complex algorithms which could help in the control-trajectory analysis. The report also explores the potential use of artificial intelligence (AI) to enhance automation. Even though AI brings huge advantages to aeronautics, it could be tricky to introduce on safety-critical systems like the FADEC due to inherent risks. The conclusion is that in this type of system, AI could soon be used to support human activity, but some risk mitigation may be needed. In conclusion, the Europa tool is a valuable addition to the verification process, offering adaptability and room for future enhancements. It has the potential to be applied across other projects within the company, contributing to improved product quality and reduced user errors

The first IEEE workshop on the Future of Research Curation and Research Reproducibility

This report describes perspectives from the Workshop on the Future of Research Curation and Research Reproducibility that was collaboratively sponsored by the U.S. National Science Foundation (NSF) and IEEE (Institute of Electrical and Electronics Engineers) in November 2016. The workshop brought together stakeholders including researchers, funders, and notably, leading science, technology, engineering, and mathematics (STEM) publishers. The overarching objective was a deep dive into new kinds of research products and how the costs of creation and curation of these products can be sustainably borne by the agencies, publishers, and researcher communities that were represented by workshop participants.National Science Foundation Award #164101