Force-Moment decoupled actuation property analysis for a Generically Tilted Multirotor platform

openIl controllo di veicoli aerei autonomi è un argomento di crescente interesse, dovuto all’affascinante teoria che ha come protagonisti questi dispositivi e che può condurre a impegnative ed entusiasmanti sfide sia in campo teorico che pratico. Questo si riflette nel fatto che studi recenti sono mirati a studiare le proprietà strutturali di questi multi rotori, permettendo performance migliori rispetto ai droni standard con quattro eliche, anche in situazioni anomale e nel caso di possibili guasti. Per affrontare il problema, i momenti e le forze sono stati trattati in modo indipendente le une dagli atri, rendendo possibile lo studio di come un numero maggiore di eliche possa portare a maggior robustezza e manovrabilità del drone stesso. Questi punti vengono trattati in primo luogo disaccoppiando le dinamiche di traslazione e rotazione, che nel modello dinamico sono intrinsecamente accoppiate, successivamente viene massimizzata la capacità di attuazione delle forze che non generano momento angolare. Tutto questo viene usato per generare una traiettoria che tenga in considerazione tutti i vincoli dati e che sia immune dai guasti alle eliche.Unmanned Aerial Vehicles are a rising topic in the control theory research, due to their emerging theoretical and practical challenges. This translates into the fact that recent studies focused on the structural properties of these aerial platforms actuated by more than four rotors, arbitrarily oriented, to allow them to perform better than a standard quadrotor, even in harsh conditions and in case of possible failures. Typically, to face these problems, the forces and moments generated these platforms turn out to be decoupled and can be treated independently. In this thesis, the goal is to study the actuation and robustness properties of these multirotor platforms varying their physical construction parameters. The attention is first focused on the decoupling between the translational and rotational dynamics, that are intrinsically coupled in the original model, and then on the maximization of the force actuation capability that generates no angular momentum. Lastly all these studies are combined to plan a trajectory subject to all the given constraints, and that is not affected by propellers’ failure

Model-Independent Comparison Between Factorization Algebras and Algebraic Quantum Field Theory on Lorentzian Manifolds

This paper investigates the relationship between algebraic quantum field theories and factorization algebras on globally hyperbolic Lorentzian manifolds. Functorial constructions that map between these two types of theories in both directions are developed under certain natural hypotheses, including suitable variants of the local constancy and descent axioms. The main result is an equivalence theorem between (Cauchy constant and additive) algebraic quantum field theories and (Cauchy constant, additive and time-orderable) prefactorization algebras. A concept of 17-involution for the latter class of prefactorization algebras is introduced via transfer. This involves Cauchy constancy explicitly and does not extend to generic (time-orderable) prefactorization algebras

Categorical Aspects of Algebraic Quantum Field Theory

The aim of this work is to introduce and investigate 3 distinct problems in Algebraic Quantum Field Theory whose solution relies on (higher) multicategorical methods. More precisely, we will discuss a model-independent comparison between Algebraic Quantum Field Theory and Factorization Algebras, a 2-categorical notion of algebraic quantum field theory more sensitive to global aspects of gauge theories than previous approaches and a ``smoothness axiom'' for algebraic quantum field theories encoding ``smooth responses of observable algebras'' to ``smooth variations of spacetimes''

Categorical Aspects of Algebraic Quantum Field Theory

The aim of this work is to introduce and investigate 3 distinct problems in Algebraic Quantum Field Theory whose solution relies on (higher) multicategorical methods. More precisely, we will discuss a model-independent comparison between Algebraic Quantum Field Theory and Factorization Algebras, a 2-categorical notion of algebraic quantum field theory more sensitive to global aspects of gauge theories than previous approaches and a ``smoothness axiom'' for algebraic quantum field theories encoding ``smooth responses of observable algebras'' to ``smooth variations of spacetimes''

Categorification of algebraic quantum field theories

This paper develops a concept of 2-categorical algebraic quantum field theories (2AQFTs) that assign locally presentable linear categories to spacetimes. It is proven that ordinary AQFTs embed as a coreflective full 2-subcategory into the 2-category of 2AQFTs. Examples of 2AQFTs that do not come from ordinary AQFTs via this embedding are constructed by a local gauging construction for finite groups, which admits a physical interpretation in terms of orbifold theories. A categorification of Fredenhagen's universal algebra is developed and also computed for simple examples of 2AQFTs

Multi-species habitat models highlight the key importance of flooded reedbeds for inland wetland birds: implications for management and conservation

Abstract Background Inland wetlands are crucial for biodiversity conservation, especially in highly-urbanized landscapes. In the European Union, many wetlands are included in the EU 'Natura 2000' network, the main tool for biodiversity conservation over the continent, which requires the development of site-specific management plans. Clear and feasible recommendations are necessary to provide site managers with effective tools for the maintenance of biodiversity in these unstable environments. Birds are excellent umbrella species, therefore a management targeted at increasing habitat suitability for focal bird species would likely benefit broader wetland biological communities. Methods During spring–summer 2017, we collected presence/absence data for 10 bird species of conservation interest at a site scale for 21 Natura 2000 sites. We also carried out a point count survey to detect presence/absence of four reedbed-dwelling species at 75 points. At the site level, we estimated landscape characteristics from regional GIS-layers, whereas fine-scaled habitat composition was recorded on the field within a 100 m-buffer around the 75 points. We analysed the effect of the extent of different habitats on species' occurrence probability by means of multi-species binomial multivariate adaptive regression splines (MARS) at both scales. We also run species-specific MARS models to compare their performance with those of multi-species models. Results At the site scale, the extent of the reedbeds/mires was positively associated with the occurrence of all species of conservation concern. At the point-count scale, reedbed extent positively predicted species' occurrence, but only in presence of patches of clear shallow water. Species-specific MARS models showed qualitatively similar results for some species, but generally were outperformed by multi-species ones. Conclusions Multi-species MARS models confirmed to be an efficient tool in disclosing species-habitat relationships even for set of species including scarce taxa and when only short-term monitoring data are available. In terms of conservation measures, our findings stress the importance of Phragmites australis reedbed as a key habitat for avian biodiversity, but only when it is flooded and interspersed with scattered patches of open water. The preservation of wide (> 100/150 ha) and flooded reedbeds structured in spots of no less than 2 ha emerges as the main conservation measure for the long-term conservation of the threatened avifauna of inland pre-Alpine wetlands

Echocardiographic and hemodynamic determinants of right coronary artery flow reserve and phasic flow pattern in advanced non-ischemic cardiomyopathy

<p>Abstract</p> <p>Background</p> <p>In patients with advanced non-ischemic cardiomyopathy (NIC), right-sided cardiac disturbances has prognostic implications. Right coronary artery (RCA) flow pattern and flow reserve (CFR) are not well known in this setting. The purpose of this study was to assess, in human advanced NIC, the RCA phasic flow pattern and CFR, also under right-sided cardiac disturbances, and compare with left coronary circulation. As well as to investigate any correlation between the cardiac structural, mechanical and hemodynamic parameters with RCA phasic flow pattern or CFR.</p> <p>Methods</p> <p>Twenty four patients with dilated severe NIC were evaluated non-invasively, even by echocardiography, and also by cardiac catheterization, inclusive with Swan-Ganz catheter. Intracoronary Doppler (Flowire) data was obtained in RCA and left anterior descendent coronary artery (LAD) before and after adenosine. Resting RCA phasic pattern (diastolic/systolic) was compared between subgroups with and without pulmonary hypertension, and with and without right ventricular (RV) dysfunction; and also with LAD. RCA-CFR was compared with LAD, as well as in those subgroups. Pearson's correlation analysis was accomplished among echocardiographic (including LV fractional shortening, mass index, end systolic wall stress) more hemodynamic parameters with RCA phasic flow pattern or RCA-CFR.</p> <p>Results</p> <p>LV fractional shortening and end diastolic diameter were 15.3 ± 3.5 % and 69.4 ± 12.2 mm. Resting RCA phasic pattern had no difference comparing subgroups with vs. without pulmonary hypertension (1.45 vs. 1.29, p = NS) either with vs. without RV dysfunction (1.47 vs. 1.23, p = NS); RCA vs. LAD was 1.35 vs. 2.85 (p < 0.001). It had no significant correlation among any cardiac mechanical or hemodynamic parameter with RCA-CFR or RCA flow pattern. RCA-CFR had no difference compared with LAD (3.38 vs. 3.34, p = NS), as well as in pulmonary hypertension (3.09 vs. 3.10, p = NS) either in RV dysfunction (3.06 vs. 3.22, p = NS) subgroups. </p> <p>Conclusion</p> <p>In patients with chronic advanced NIC, RCA phasic flow pattern has a mild diastolic predominance, less marked than in LAD, with no effects from pulmonary artery hypertension or RV dysfunction. There is no significant correlation between any cardiac mechanical-structural or hemodynamic parameter with RCA-CFR or RCA phasic flow pattern. RCA flow reserve is still similar to LAD, independently of those right-sided cardiac disturbances.</p