360 research outputs found
Optimal Trajectory Tracking for an Autonomous UAV
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).
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
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 vehicleâs 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 ârealisticâ 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
Obstructive sleep apnoea syndrome (OSAS): effects on the vestibular system
Aim of the present study was to evaluate the effects of obstructive sleep apnoea syndrome (OSAS) on the peripheral and central vestibular
system, by means of a case series prospective study at the University referral centre of Otolaryngology Head and Neck Surgery; 45 consecutive
patients suffering from OSAS were compared with a control group of 30 volunteer subjects selected from among the department
employees. Severity of the disease was evaluated by means of cardio-respiratory function monitoring during sleep; the apnoea-hypopnoea
index was calculated. Both groups underwent: 1) head and neck examination; 2) fibre-optic examination; 3) pure tone audiometry; 4) evaluation
of eye movement disorders using oculomotility tests recorded with the help of video-nystagmography; 5) caloric vestibular responses
recorded with video-nystagmography; 6) auditory brainstem response. Results, when evaluating our data, showed that the peripheral vestibular
system may become asymmetric due to hypoxic damage while the central vestibular system corrects this disequilibrium
Uvulopalatopharyngoplasty with tonsillectomy in the treatment of severe OSAS
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
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
Implant-Based Breast Reconstruction after Risk-Reducing Mastectomy in BRCA Mutation Carriers: A Single-Center Retrospective Study
Women with BRCA gene mutations have a higher lifetime risk of developing breast cancer. Furthermore, cancer is usually diagnosed at a younger age compared to the wild-type counterpart. Strategies for risk management include intensive surveillance or risk-reducing mastectomy. The latter provides a significant reduction of the risk of developing breast cancer, simultaneously ensuring a natural breast appearance due to the preservation of the skin envelope and the nipple-areola complex. Implant-based breast reconstruction is the most common technique after risk-reducing surgery and can be achieved with either a submuscular or a prepectoral approach, in one or multiple stages. This study analyzes the outcomes of the different reconstructive techniques through a retrospective review on 46 breasts of a consecutive, single-center case series. Data analysis was carried out with EpiInfo version 7.2. Results of this study show no significant differences in postoperative complications between two-stage tissue expander/implant reconstruction and direct-to-implant (DTI) reconstruction, with DTI having superior aesthetic outcomes, especially in the prepectoral subgroup. In our experience, the DTI prepectoral approach has proven to be a safe and less time-consuming alternative to the submuscular two-stage technique, providing a pleasant reconstructed breast and overcoming the drawbacks of subpectoral implant placement
The Harvesting Memories Project: Historical ecology and landscape changes of the Sicani Mountains in Sicily
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
The monumental olive trees as biocultural heritage of mediterranean landscapes: The case study of sicily
Monumental olive trees, with their longevity and their remarkable size, represent an important information source for the comprehension of the territory where they grow and the human societies that have kept them through time. Across the centuries, olive trees are the only cultivated plants that tell the story of Mediterranean landscapes. The same as stone monuments, these green monuments represent a real Mediterranean natural and cultural heritage. The aim of this paper is to discuss the value of monumental trees as âbiocultural heritageâ elements and the role they play in the interpretation of the historical stratification of the landscape. We present the results of a survey of the most significant olive trees growing in Sicily. The selection was based on the âmonumentalityâ aspects of trees, taking into account dendrometric parameters and environmental contexts. The collected dataset constitutes a heterogeneous sample of 367 specimens of considerable size that, in some cases, reach a circumference of about 19 m. Starting from the data presented here, the whole Sicilian territory shows a historical relationship between human and olive. The presence of these plant monuments is, therefore, evidence of longâterm, often centennial, landscapes as a result of sustainable use of the territory
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