364 research outputs found

    Optimal Trajectory Tracking for an Autonomous UAV

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    The aim of the present project is the design of optimal flight trajectories for an automomous aerial vehicle which is expected to reach the desired locations in the operational environment expressed in terms of planned waypoints. The navigation must be performed with the vehicle's best effort, i.e. with the lowest cost. Hence, we want to minimize the input energy, a function of the inputs for the mathematical model which describes the dynamics of the vehicle. The trajectory must satisfy all the constraints and pass through all the planned waypoints. Assuming the vehicle as a point mass model, the best solution has been investigated through a genetic algorithm search procedure. The optimisation problem has been solved by modifying a micro-genetic algorithm software which was initially developed by D.L. Carroll. Between all the possible trajectories we select the more "realistic" connections among the waypoints. First of all, we have left out the trajectories with discontinuity in the derivatives as these are not feasible by the real aircraft. The polynomial spline is a suitable candidate to solve our problem. The algorithm splits the trajectory in sub-trajectories which join a sequence of three waypoints. Starting from the first three waypoints, the following sub-trajectories are superimposed keeping the first waypoint coincident with the last of the previous sub-trajectory. The sequence of polynomials is initialized assuming that jumps in the direction of flight are avoided pointing the heading angle in the presumed direction of flight. The optimal trajectory is a trade-off amongst three factors: the required energy cost, the minimum distance from the required waypoint and the feasibility of the trajectory. Results obtained with this optimization procedure are presente

    Natura e architettura nel giardino di Villa Florio-Pignatelli (Palermo, Sicilia).

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    ABSTRACT.\u2013 Amongst the Sicilian historical gardens it is merited to remember the ornamental garden design of Villa Florio- Pignatelli, situated in the western periphery of Palermo. The building, and probably the garden too, are from the second half of the 18. century. This article contains the result of a cognitive study of its history, architecture and vegetal composition, based on field studies in the garden itself, on bibliographical and archival work. In 1838 it was sold by the Duke of Cumia to Vincenzo Florio, who in following conceded it to his son Ignazio. Already at this time, there was a garden with a "flora all\u2019Italiana" behind the Villa, which had circular vials in radial order, demarcated with a box-hedge (Buxus sempervirens), much like a small reproduction of the more famous and celebrated Villa Giulia (1777), the first public garden in the town.The elegance of the garden's proportions is based on at least four geometric orders interacting with each other. They reveal evi- dence of important fixed points or "topoi" of the garden; these affirm that the apparent simplicity contains complicated arith- metic and geometric relations in an exceptional union of architectural and botanical significance

    Optimal Trajectory Tracking for an Autonomous UAV

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    The aim of the present project is the design of optimal flight trajectories for an automomous aerial vehicle which is expected to reach the desired locations in the operational environment expressed in terms of planned waypoints. The navigation must be performed with the vehicle’s best effort, i.e. with the lowest cost. Hence, we want to minimize the input energy, a function of the inputs for the mathematical model which describes the dynamics of the vehicle. The trajectory must satisfy all the constraints and pass through all the planned waypoints. Assuming the vehicle as a point mass model, the best solution has been investigated through a genetic algorithm search procedure. The optimisation problem has been solved by modifying a micro-genetic algorithm software which was initially developed by D.L. Carroll. Between all the possible trajectories we select the more “realistic” connections among the waypoints. First of all, we have left out the trajectories with discontinuity in the derivatives as these are not feasible by the real aircraft. The polynomial spline is a suitable candidate to solve our problem. The algorithm splits the trajectory in sub-trajectories which join a sequence of three waypoints. Starting from the first three waypoints, the following sub-trajectories are superimposed keeping the first waypoint coincident with the last of the previous sub-trajectory. The sequence of polynomials is initialized assuming that jumps in the direction of flight are avoided pointing the heading angle in the presumed direction of flight. The optimal trajectory is a trade-off amongst three factors: the required energy cost, the minimum distance from the required waypoint and the feasibility of the trajectory. Results obtained with this optimization procedure are presented

    Uvulopalatopharyngoplasty with tonsillectomy in the treatment of severe OSAS

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    Objective: To establish the efficacy of uvulopalatopharyngoplasty with tonsillectomy for treating selected patients with severe obstructive sleep apnea syndrome Methodology: Retrospective study of patients who underwent clinical/instrumental evaluation and surgical treatment. Setting: University ENT division with a tertiary snoring referral center Participants: Twenty-two patients with normal body mass index affected by severe obstructive sleep apnea syndrome- Main outcome measures: Pre and post operative cardiopulmonary monitoring during sleep, daytime sleepiness evaluation, post treatment complication recording. Results: Complete response to therapy was obtained in 78% of patients. Four patients had relief of symptoms but retained apnea-hypopnea index scores greater than 5 Conclusions: Uvulopalatopharyngoplasty associated with tonsillectomy can be employed safely to treat patients with normal body mass index who suffer from severe obstructive sleep apne

    Management of benign paroxysmal positional vertigo of lateral semicircular canal by Gufoni's manoeuvre

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    Benign paroxysmal positional vertigo (BPPV) of lateral semicircular canal (LSC) is one of the rarer forms of BPPV as compared to posterior semicircular canal BPPV. Various particle repositioning manoeuvres have been described in the literature as a mode of treating this condition Purpose: Evaluation and discussion of the procedure of the Gufoni\u2019s manoeuvre and its advantages in the treatment of BPPV of LSC Material and methods: Prospective study of 58 patients affected by LSC BPPV who where office-treated with Gufoni\u2019s manoeuvre Results: Seventy-nine percent of the patients so treated had complete resolution of symptons, and 6,9% did not show any improvement in their symptoms. The remaining 13,8% had a conversion into posterior semicircular canal BPPV during treatment and were successfully treated with Epley\u2019s or Semont\u2019s manoeuvre. Conclusions: Gufoni\u2019s manoeuvre is effective in treating patients suffering from BPPV of LSC; it is simple to perform; there are not many movements to execute, it needs low timeof positioning, and positions are comfortable to the patien

    The Harvesting Memories Project: Historical ecology and landscape changes of the Sicani Mountains in Sicily

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    The Harvesting Memories project aims to investigate the historical landscape dynamics in an inner area of the Sicani Mountains district in Western Sicily (Contrada Castro, Corleone-Palermo). The interdisciplinary approach of the project allowed us to combine and integrate methods from different disciplines such as historical ecology, landscape archaeology, archaeobotany and GIS-based spatial analysis. In this paper some results have been summarized. The comparison between land mosaic change during the last 60 years, the relationship between site catchment area and land suitability and the correlation between archaeobotanical and phytosociological data. This approach underlined the relevance of the historical ecology for understanding landscape trajectories and planning strategy of suitable development of rural areas
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