Push & Pull: autonomous deployment of mobile sensors for a complete coverage

Mobile sensor networks are important for several strategic applications devoted to monitoring critical areas. In such hostile scenarios, sensors cannot be deployed manually and are either sent from a safe location or dropped from an aircraft. Mobile devices permit a dynamic deployment reconfiguration that improves the coverage in terms of completeness and uniformity. In this paper we propose a distributed algorithm for the autonomous deployment of mobile sensors called Push&Pull. According to our proposal, movement decisions are made by each sensor on the basis of locally available information and do not require any prior knowledge of the operating conditions or any manual tuning of key parameters. We formally prove that, when a sufficient number of sensors are available, our approach guarantees a complete and uniform coverage. Furthermore, we demonstrate that the algorithm execution always terminates preventing movement oscillations. Numerous simulations show that our algorithm reaches a complete coverage within reasonable time with moderate energy consumption, even when the target area has irregular shapes. Performance comparisons between Push&Pull and one of the most acknowledged algorithms show how the former one can efficiently reach a more uniform and complete coverage under a wide range of working scenarios.Comment: Technical Report. This paper has been published on Wireless Networks, Springer. Animations and the complete code of the proposed algorithm are available for download at the address: http://www.dsi.uniroma1.it/~novella/mobile_sensors

P&P protocol: local coordination of mobile sensors for self-deployment

The use of mobile sensors is of great relevance for a number of strategic applications devoted to monitoring critical areas where sensors can not be deployed manually. In these networks, each sensor adapts its position on the basis of a local evaluation of the coverage efficiency, thus permitting an autonomous deployment. Several algorithms have been proposed to deploy mobile sensors over the area of interest. The applicability of these approaches largely depends on a proper formalization of rigorous rules to coordinate sensor movements, solve local conflicts and manage possible failures of communications and devices. In this paper we introduce P&P, a communication protocol that permits a correct and efficient coordination of sensor movements in agreement with the PUSH&PULL algorithm. We deeply investigate and solve the problems that may occur when coordinating asynchronous local decisions in the presence of an unreliable transmission medium and possibly faulty devices such as in the typical working scenario of mobile sensor networks. Simulation results show the performance of our protocol under a range of operative settings, including conflict situations, irregularly shaped target areas, and node failures.Comment: Technical repor

Neural network topology for wind turbine analysis

In this work Artificial Neural Networks (ANN) are used for a multi-target optimization of the aerodynamics of a wind turbine blade. The Artificial Neural Network is used to build a meta-model of the blade, which is then optimized according to the imposed criteria. The neural networks are trained with a data set built by a series of CFD simulations and their configuration (number of neurons and layers) selected to improve performances and avoid over-fitting. The basic configuration of the airfoil is the profile S809, which is commonly used in horizontal axis wind turbines (HAWT), equipped with a Coanda jet. The design position and momentum of the jet are optimized to maximize aerodynamic efficiency and minimize the power required to activate the Coanda Jet

In silico clinical trials through AI and statistical model checking

A Virtual Patient (VP) is a computational model accounting for individualised (patho-) physiology and Pharmaco-Kinetics/Dynamics of relevant drugs. Availability of VPs is among the enabling technology for In Silico Clinical Trials. Here we shortly outline the state of the art as for VP generation and summarise our recent work on Artificial Intelligence (AI) and Statistical Model Checking based generation of VPs

Quantum Characterization of a Werner-like Mixture

We introduce a Werner-like mixture [R. F. Werner, Phys. Rev. A {\bf 40}, 4277 (1989)] by considering two correlated but different degrees of freedom, one with discrete variables and the other with continuous variables. We evaluate the mixedness of this state, and its degree of entanglement establishing its usefulness for quantum information processing like quantum teleportation. Then, we provide its tomographic characterization. Finally, we show how such a mixture can be generated and measured in a trapped system like one electron in a Penning trap.Comment: 8 pages ReVTeX, 8 eps figure

Intention to be vaccinated for COVID-19 among italian nurses during the pandemic

Background: While the COVID-19 pandemic has spread globally, health systems are overwhelmed by both direct and indirect mortality from other treatable conditions. COVID-19 vaccination was crucial to preventing and eliminating the disease, so vaccine development for COVID-19 was fast-tracked worldwide. Despite the fact that vaccination is commonly recognized as the most effective approach, according to the World Health Organization (WHO), vaccine hesitancy is a global health issue. Methods: We conducted a cross-sectional online survey of nurses in four different regions in Italy between 20 and 28 December 2020 to obtain data on the acceptance of the upcoming COVID-19 vaccination in order to plan specific interventions to increase the rate of vaccine coverage. Results: A total of 531 out of the 5000 nurses invited completed the online questionnaire. Most of the nurses enrolled in the study (73.4%) were female. Among the nurses, 91.5% intended to accept vaccination, whereas 2.3% were opposed and 6.2% were undecided. Female sex and confidence in vaccine efficacy represent the main predictors of vaccine intention among the study population using a logistic regression model, while other factors including vaccine safety concerns (side effects) were non-significant. Conclusions: Despite the availability of a safe and effective vaccine, intention to be vaccinated was suboptimal among nurses in our sample. We also found a significant number of people undecided as to whether to accept the vaccine. Contrary to expectations, concerns about the safety of the vaccine were not found to affect the acceptance rate; nurses’ perception of vaccine efficacy and female sex were the main influencing factors on attitudes toward vaccination in our sample. Since the success of the COVID-19 immunization plan depends on the uptake rate, these findings are of great interest for public health policies. Interventions aimed at increasing employee awareness of vaccination efficacy should be promoted among nurses in order to increase the number of vaccinated people

Restos fúngicos del primer depósito de chert de origen hidrotermal del Mesozoico, Jurásico del Macizo del Deseado, Patagonia, Argentina

Se describe e ilustra una variedad de restos permineralizados de hifas, esporas y otros propágulos fúngicos asociados a plantas vasculares en diversos estados de preservación del primer yacimiento de chert de origen hidrotermal del Mesozoico, Jurásico del Macizo del Deseado, Patagonia, Argentina. Entre los propágulos identificados hay estructuras de fructificación tipo picnidios que son en la actualidad comúnmente producidas por ascomicetes y estructuras vesiculares que recuerdan a esporangios de chitridiomycetes. Estos propágulos se han encontrado asociados a restos vegetales en diferentes grados de descomposición y a tejidos con células esclerificadas e hipertrofiadas. Aún es prematuro hablar del tipo de interacción o asociación hongo-planta que los fósiles encontrados representarían; sin embargo, en función de la asociación de varios de estos hongos con restos vegetales en estado de descomposición es probable que hubieran actuado como saprótrofos. La asociación de probables esporangios de chitridiomycetes con células esclerificadas e hipertrofiadas sugiere una interacción directa entre los hongos y los vegetales, donde los hongos habrían provocado como respuesta modificaciones a nivel celular en las plantas hospedantes. Esto brinda los primeros datos sobre hongos en depósitos de chert de origen hidrotermal del Mesozoico, en particular del Jurásico, ampliando su registro fósil, especialmente para Argentina, una región escasamente conocida paleomicológicamente. La biota descripta para los depósitos de origen hidrotermal jurásicos de Patagonia sumada al reciente hallazgo de hongos permineralizados permite realizar diferentes analogías con el ecosistema preservado en los cherts de Rhynie (Escocia). De esta manera, el análisis de los hongos fósiles de estos depósitos, provee una oportunidad única de incrementar nuestro conocimiento sobre los ecosistemas terrestres pasados, en particular aquellos de origen hidrotermal, así como sobre las características biológicas y ecológicas de las comunidades fúngicas adaptadas a las condiciones fisicoquímicas de este tipo de ambiente.Sesiones libresFacultad de Ciencias Naturales y Muse

Contractive Schroedinger cat states for a free mass

Contractive states for a free quantum particle were introduced by Yuen [Yuen H P 1983 Phys. Rev. Lett. 51, 719] in an attempt to evade the standard quantum limit for repeated position measurements. We show how appropriate families of two- and three component ``Schroedinger cat states'' are able to support non-trivial correlations between the position and momentum observables leading to contractive behavior. The existence of contractive Schroedinger cat states is suggestive of potential novel roles of non-classical states for precision measurement schemes.Comment: 24 pages, 7 encapsulated eps color figures, REVTeX4 style. Published online in New Journal of Physics 5 (2003) 5.1-5.21. Higher-resolution figures available in published version. (accessible at http://www.njp.org/