Une vision sur le bilinguisme selon les bilingues et les monolingues

La classe de FLE est un environnement bilingue d'apprentissage. Enseigner le FLE requiert, par conséquent, que l’enseignant comprenne l'importance d'enseigner une langue hégémonique, ainsi que toutes les autres questions relatives à l'acquisition des langues. Étant bilingue, il est primordial que l’enseignant connaisse son propre bilinguisme, en sache l'importance et soit en mesure de former des bilingues qui le comprennent également à leur tour. Le but de ce travail vise à analyser la vision du locuteur bilingue à propos de son bilinguisme et de mettre donc en évidence les mythes et les préjugés qui entourent le terme en question. Pour développer cette recherche, on a proposé un questionnaire contenant des questions liées aux opinions des répondants en matière de bilinguisme. Les informateurs ont été divisés en 3 groupes d’ environ 10 personnes : étudiants de lettres bilingues parce qu’en double licence portugais-français; étudiants de FLE dans des écoles spécialisées ; personnes monolingues extérieures à l'Université. Si cette recherche est toujours dans les premiers stades,il a déjà été possible de confirmer certaines hypothèses à partir des données recueillies. La plupart des répondants croit, par exemple, qu’être un bilingue c’est avoir une très haute compétence dans toutes les habiletés de chaque langue.Fil: Costa Mendes, Júlia. Universidade Federal de PelotasFil: Mozzillo, Isabella. Universidade Federal de Pelota

Heterogeneous design and mechanical analysis of HELIAS 5-B helium-cooled pebble bed breeding blanket concept

One of the most challenging objectives of the European research concerning nuclear fusion technology, promoted by the EUROfusion consortium, is to bring stellarator-type nuclear fusion devices to maturity. To this purpose, studies on a large HELIcal-axis advanced stellarator (HELIAS), extrapolated from Wendelstein 7-X and based on a 5-fold symmetry (HELIAS 5-B), are currently ongoing. The HELIAS 5-B stellarator reactor will be endowed with a breeding blanket (BB) system to allow for the self-sustainability of the nuclear fusion reaction and make it suitable for electricity generation. In this paper, we present the first ever heterogeneous mechanical design and the preliminary structural assessment of a bean-shaped ring of a HELIAS 5-B BB sector. The proposed mechanical design, which is based on the helium-cooled pebble bed (HCPB) BB concept and developed according to the “sandwich” architecture, foresees an actively cooled segment box connected to a back-supporting structure equipped with manifolds. The internal region (breeding zone) is reinforced by actively cooled steel plates. The proposed heterogeneous design was checked against nominal loads and an in-box loss of coolant accidental scenario, which is a typical design driver for BBs. The assessment has been performed according to the RCC-MRx structural design code. Our results are herewith presented and critically discussed, focusing on the potential follow-up of the HELIAS 5-B HCPB BB design

Design of the Active Attitude Determination and Control System for the e-st@r cubesat

One of the most limiting factors which affects pico/nano satellites capabilities is the poor accuracy in attitude control. To improve mission performances of this class of satellites, the capability of controlling satellite’s attitude shall be enhanced. The paper presents the design, development and verification of the Active Attitude Determination and Control System (A-ADCS) of the E-ST@R Cubesat developed at Politecnico di Torino. The heart of the system is an ARM9 microcontroller that manages the interfaces with sensors, actuators and the on-board computer and performs the control tasks. The attitude manoeuvres are guaranteed by three magnetic torquers that contribute to control the satellite in all mission phases. The satellite attitude is determined elaborating the data provided by a COTS Inertial Measurement Unit, a Magnetometer and the telemetries of the solar panels, used as coarse Sun sensor. Different algorithms have been studied and then implemented on the microprocessor in order to determine the satellite attitude. Robust and optimal techniques have been used for the controller design, while stability and performances of the system are evaluated to choose the best control solution in every mission phase. A mathematical model of the A-ADCS and the external torques acting on the satellite, its dynamics and kinematics, is developed in order to support the design. After the design is evaluated and frozen, a more detailed simulation model is developed. It contains non-ideal sensors and actuators models and more accurate system disturbances models. New numerical simulations permit to evaluate the behaviour of the controller under more realistic mission conditions. This model is the basic element of the Hardware In The Loop (HITL) simulator that is developed to test the A-ADCS hardware (and also the whole satellite). Testing an A-ADCS on Earth poses some issues, due to the difficulties of reproducing real orbit conditions (i.e. apparent sun position, magnetic field, etc). This is especially true in the case of low cost projects, for which complex testing facilities are usually not available. Thanks to a good HITL simulator it is possible to test the system and its “real in orbit” behaviour to a certain grade of accuracy saving money and time for verification. The paper shows the results of the verification of the ADCS by means of the HITL strategy, which are consistent with the expected values

Lessons learned of a systematic approach for the e-st@r-II CubeSat environmental test campaign

CubeSat-standard satellites have become more and more popular during last years. Education objectives, mainly pursued in the first CubeSat projects, have given way to the design of missions with other-than-education objectives, like Earth observation and technology demonstration. These new objectives require the development of appropriate technology. Moreover, is necessary to ensure a certain level of reliability, because education-driven mission often failed. In 2013 the ESA Education Office launched the Fly Your Satellite! Initiative devoted to provide six university teams with the support of ESA specialists for the verification phase of their CubeSats. Within this framework, the CubeSat Team at Politecnico di Torino developed the e-st@r-II CubeSat. E-st@r-II is a 1U satellite with educational and technology demonstration objectives: to give hands-on experience to university students; to demonstrate the capability of autonomous attitude determination and control, through the design, development and test in orbit of an A-ADCS; and to test in orbit COTS technology and in-house developed hardware and software (as UHF communication subsystem and software for on-board and data handling subsystem). The paper describes the application of a systematic approach to the definition, planning and execution of environmental test campaign of e- st@r-II CubeSat and the gathered lessons learned. The approach is based on procedures designed and assessed for the vibrations and thermal-vacuum cycling tests of a CubeSat accordingly to ECSS rules and with the support of ESA specialists. Concretely, ECSS application, tailored to fit a CubeSat project, allowed to define a test plan oriented to reduce verification duration and cost, which lead to a lean verification execution. Moreover, the interaction with ESA thermal and mechanical experts represented a valuable aid to increase the Team know-how and to improve and optimise the verification plan and its execution. The planning encompasses the analysis of the requirements to be verified that have been gathered in such a way that the tests duration has been reduced. The required tests, like thermal- vacuum cycling and bake-out tests, have been combined in order to speed-up the verification campaign. The tests outputs shown that the satellite is able to withstand launch and space environment. Furthermore, satellite expected functionalities have been tested and verified when the CubeSat is subjected to space environment, in terms of temperature and vacuum conditions. In conclusion, it has been successfully demonstrated that the proposed approach allows executing a lean CubeSat verification campaign against environmental requirements following a systematic approach based on ECSS

Autonomous Neuro-Fuzzy Solution for Fault Detection and Attitude Control of a 3U Cubesat

In recent years, thanks to the increase of the know-how on machine-learning techniques and the advance of the computational capabilities of on-board processing, algorithms involving artificial intelligence (i.e. neural networks and fuzzy logics) have began to spread even in the space applications. Nowadays, thanks to these reasons, the implementation of such techniques is becoming realizable even on smaller platforms, such as CubeSats. The paper presents an algorithm for the fault detection and for the fault-tolerant attitude control of a 3U CubeSat, developed in MathWorks Matlab & Simulink environment. This algorithm involves fuzzy logic and multi-layer feed-forward online-trained neural network (percep- tron). It is utilized in a simulation of a CubeSat satellite placed in LEO, considering as available attitude con- trol actuators three magnetic torquers and one reaction wheel. In particular, fuzzy logics are used for the fault detection and isolation, while the neural network is employed for adapting the control to the perturbation introduced by the fault. The simulation is performed considering the attitude of the satellite known without measurement error. In addition, the paper presents the system, simulator and algorithm architecture, with a particular focus on the design of fuzzy logics (connection and implication operators, rules and input/output qualificators) and the neural network architecture (number of layers, neurons per layer), threshold and activation func- tions, offline and online training algorithm and its data management. With respect to the offline training, a model predictive controller has been adopted as supervisor. In con- clusion the paper presents the control torques, state variables and fuzzy output evolution, in the different faulty configurations. Results show that the implementation of the fuzzy logics joined with neural networks provide good ro- bustness, stability and adaptibility of the system, allowing to satisfy specified performance requirements even in the event of a malfunctioning of a system actuator

Structural assessment of the gripper interlock of the DEMO breeding blanket transporter

The maintenance of the DEMO Breeding Blanket (BB) remotely is a crucial aspect in development of the DEMO power plant. It is a challenge due to the huge mass of the BB segment of about 180 tons. A new concept for the BB transporter has recently been developed. To properly grip and manipulate each BB segment, the BB transporter has been equipped with a gripper interlock. Due to the geometry of the BB and the vacuum vessel, the attachment point on the BB segment is not aligned with its center of gravity. Hence in addition to the vertical lifting load, large moments about the horizontal axes need to be reacted.The work discussed here concerns the structural analysis conducted on the gripper interlock; its structural integrity has been checked against the most severe load conditions that include also seismic loads according to the EN13001. Elastic analyses were performed using a finite element model in accordance with EN 13001-3-1:2012 + A2:2018, Cranes - General Design - Part 3-1: Limit States and proof competence of steel structure. The effect of the gap sizes at the contact surfaces between gripper interlock and BB after engagement as well as the effect of different friction coefficients on the sliding areas were assessed. The improvements of the design based on the structural analysis are presented, too

A tool for nano-satellite functional verification: comparison between different inthe-loop simulation configurations

This paper describes the simulator technology and the verification campaign for the e-st@r CubeSats family, developed at Politecnico di Torino. The satellites’ behavior has been investigated using a Model and Simulation Based Approach. One of the critical issue in the verification and validation of any space vehicle is the impossibility to fully test some features due to the particular and often un-reproducible environment in which it will operate. Simulations result as one of the best means for testing space system capabilities as it may help to overcome the abovementioned problem. In order to perform different simulation configurations for e-st@r CubeSats, an in-house simulator (named StarSim) has been developed. It is a unique infrastructure, modular and versatile, capable of supporting any desired configuration of the system under test, ranging from full algorithm in the loop simulations (AIL), and gradually inserting satellite hardware, until a complete hardware in the loop (HIL) simulation is performed. When a verification campaign is led on a real object, pure AIL computer based simulations (in which all the equipment and mission conditions are reproduced by virtual models) are not sufficient to test the actual software and hardware to a high degree of confidence since real systems can exhibit random and unpredictable dynamics difficult to be perfectly modeled (i.e. communication delays, uncertainties, and so on). For these reasons, Software In The Loop (SIL), Controller In The Loop (CIL) and HIL simulations were planned. SIL simulations foresee that algorithms are written in the final programming language and executed on ground hardware. In CIL simulations, the software runs on the flight processor while other system’s element are still kept virtual. In HIL simulation, the real hardware (i.e. sensors, actuators, and power sources) are included in the loop. In this paper, after the details of the simulator architecture and its characteristics are described, an exhaustive comparison between AIL and HIL simulations is presented, highlighting main differences and singularities: similar trends of the sensible system’s variables are reached but not identical performances (i.e. absolute and average pointing error and stability, attitude determination accuracy, battery charging and discharging duration) arose analyzing the values. Moreover, it is demonstrated how the technology here presented can effectively support and improve the verification and validation activities for a nano-satellite, by increasing the confidence level on the mission objectives achievement

MOTIVAÇÕES PARA A ALTERNÂNCIA DE CÓDIGO NO DISCURSO BILÍNGÜE

El objetivo del presente trabajo fue investigar la manera por la cual se organizan las situaciones comunicativas en una familia cuya modalidad lingüística es distinta a la monolingüe. Para llegar a ese fin, fue imprescindible analizar los mecanismos que desencadenan el empleo de cada uno de los dos sistemas - el portugués y el español -, las motivaciones de carácter consciente o inconsciente y las exigencias lingüísticas, sociolingüísticas y emocionales responsables por el constante pasaje de un idioma a otro por parte de ambos hablantes estudiados, una eqüilingüe portugués-español y su marido, bilingüe desequilibrado de las mismas lenguas con dominancia en el portugués

Severe obstructive sleep disorders in Prader-Willi syndrome patients in southern Italy

Sleep-related disordered breathing (SDB) is very common in paediatric patients affected by Prader-Willi Syndrome (PWS). However, data addressing SBD patterns and their management are lacking. The aim of the present study was to analyse SDB features in 14 PWS patients (age range, 8 months-17 years). Polygraphic registration (PG) during a 12-h nocturnal sleep was performed in all patients. Obstructive and central apnoea indices and oxygen saturation (SpO2) were recorded along with demographic and clinical data. Obstructive sleep apnoea (OSA) was diagnosed in 13/14 patients (92.9%); the mean obstructive apnoea-hypopnea index (OAHI) was 7.6 ± 4.2 events/h with a mean central apnoea index (CAI) of 0.7 ± 1.04 events/h. Time spent with SpO2 < 90% was of 0.02% [range 0–23%], with a mean oxygen desaturation index of 12.1 ± 6.9 events/h. No correlation was found between OAHI and body mass index (mean BMI 28 ± 9.8 kg/m2 and BMI z-score 2.7 ± 1.7). Conclusion: OSA was the predominant sleep-related disorder in our PWS patients, not associated with age or obesity, and appeared more severe than previously reported. Further studies addressing the underlying mechanisms are necessary in larger study populations to better design the most appropriate clinical approach.What is Known:• Sleep-related patterns and their management are very limited in patients with Prader-Willi syndrome.What is New:• Severe obstructive sleep apnoea is the most frequent sleep-related disorder in our case series