La démarche qualité à l'Ifremer

L'article présente le Système de Management de la Qualité depuis son origine dans les années 90 jusqu'à la dernière transition vers la norme ISO9001:2015

DORIS: Processing and management of Sound Velocity Profiles for echosounding applications

If a bathymetric echosounder is the essential device to carry on hydrographic surveys, other external sensors are absolutely also necessary (positioning system, motion unit or sound velocity profiler). And because sound doesn‛t go straight away into the whole bathymetric swath its measurement and processing are very sensitive for all the water column. DORIS is the very answer for an operational sound velocity profile processing

DORIS Software. New Tool to Process Sound Velocity Profiles

Hydrographic and geosciences surveys, using acoustic devices, need to use accurate water sound velocity profiles. Because the acoustic path depends on the sound velocity profile (SVP), the use of the most accurate SVP is one of the keys to conducting effective surveys (with multibeams, for instance). To date, the existing software available does not answer to both the needs of efficiency and simplicity (sometimes not so easy to operate, sometimes not so accurate). DORIS provides a handy freeware to post-process SVP for the hydrographic communities

EARS : Repositioning data management near data acquisition

European Geosciences Union General Assembly 2016 (EGU2016), 17-22 April 2016, Vienna, Austria.-- 1 pageThe EU FP7 Projects Eurofleets and Eurofleets2 are an European wide alliance of marine research centers that aim to share their research vessels, to improve information sharing on planned, current and completed cruises, on details of ocean-going research vessels and specialized equipment, and to durably improve cost-effectiveness of cruises. Within this context logging of information on how, when and where anything happens on board of the vessel is crucial information for data users in a later stage. This forms a primordial step in the process of data quality control as it could assist in the understanding of anomalies and unexpected trends recorded in the acquired data sets. In this way completeness of the metadata is improved as it is recorded accurately at the origin of the measurement. The collection of this crucial information has been done in very different ways, using different procedures, formats and pieces of software in the context of the European Research Fleet. At the time that the Eurofleets project started, every institution and country had adopted different strategies and approaches, which complicated the task of users that need to log general purpose information and events on-board whenever they access a different platform loosing the opportunity to produce this valuable metadata on-board. Among the many goals the Eurofleets project has, a very important task is the development of an “event log software” called EARS (Eurofleets Automatic Reporting System) that enables scientists and operators to record what happens during a survey. EARS will allow users to fill, in a standardized way, the gap existing at the moment in metadata description that only very seldom links data with its history. Events generated automatically by acquisition instruments will also be handled, enhancing the granularity and precision of the event annotation. The adoption of a common procedure to log survey events and a common terminology to describe them is crucial to provide a friendly and successfully metadata on-board creation procedure for the whole the European Fleet. The possibility of automatically reporting metadata and general purpose data, will simplify the work of scientists and data managers with regards to data transmission. An improved accuracy and completeness of metadata is expected when events are recorded at acquisition time. This will also enhance multiple usages of the data as it allows verification of the different requirements existing indifferent disciplinesPeer Reviewe

Les risques conchylicoles en Baie de Quiberon: Deuxième partie : le risque de prédation sur l’huître creuse Crassostrea gigas. Rapport final du projet Risco 2010-2013

L’étude « Risco » s’attache aux causes possibles de mortalités massives d’huîtres creuses, de toutesclasses d’âge, enregistrées par les concessionnaires de baie de Quiberon (France, 56), à partir de2006. Le protocole engagé en 2010, avec son volet expérimental fondé sur le suivi mensuel de 15lots d’huîtres et son volet d’imagerie in situ par sonar et vidéo, permet d’éclairer en particulier lerisque lié aux prédateurs. Une spatialisation très marquée de ce risque est mise en évidence, avec unezone à l’ouest relativement épargnée, une zone à l’est très affectée par les étoiles de mer (A. rubens,M. glacialis) et une zone intermédiaire à forte prédation de bigorneaux perceurs (O. erinacea, P.inornata). Entre ces deux groupes, la prédation est réalisée pour les ¾ par les étoiles de mer et pour¼ par les bigorneaux. Les pertes maximales ont lieu au printemps (recrudescence d’étoiles de mer) eten été (efficacité maximale de prédation). La prédation par dorades, devenue très préoccupante cesdernières années, n’a pas pu être estimée. L’analyse met aussi en évidence l’importance des mesuresd’entretien des parcs pour limiter l’incidence des prédateurs. Pour autant, la prédation n’est sansdoute pas le facteur principal des mortalités de 2006, une piste environnementale basée sur le risqued’hypoxie étant explorée par ailleurs

Les risques conchylicoles en Baie de Quiberon. Troisième partie : le risque d’hypoxie pour l’huître creuse Crassostrea gigas. Rapport final du projet Risco 2010-2013

The project “Risco”, supported by the “Pôle Mer” and funded by the Regional Council of Brittany, deals with specific risks of mortality of oysters, Crassostrea gigas, cultivated on the bottom, in a subtidal bay of South Brittany : the bay of Quiberon (56, France). Massive mortalities of oysters were reported in summer 2006 in this bay, exclusively located in the deep muddy area with a positive gradient eastward. A validated biogeochemical model was applied in order to simulate the dissolved oxygen over 2000-2006 : it revealed several episodes of hypoxia, more or less intense according to years, but with the same spatial distribution. This approach proved 2006 to be the most hypoxic year since 2000. The hypoxia was due to a rare conjunction of 3 factors : (a) a local upwelling generated by north-west winds, during a neap tide; (b) an abnormal high temperature of coastal waters; (c) probably an intense phytoplankton bloom in summertime. Due to the stratification induced, oxygen consumption near the bottom exceeded its renewal. The hydrodynamism of Mor Bras, at a larger scale, excludes any import of hypoxic water from the nearby “Baie de Vilaine”, whatever the wind or tide regime. The simulated hypoxia area fitted fairly well to the 2006 mortalities. In 2010, experimental oysters deployed at 15 stations and monitored monthly, exhibited also a lower growth rate in the same area, in spite of higher chlorophyll concentration. The application of a Dynamic Energy Budget (DEB) model to growth data confirmed the responsibility of hypoxia in abnormally slow growth rates. So hypoxia may be considered as a stressful factor limiting growth prior to mortalities. It may be concluded from our study that hydro-climatic and trophic conditions have the capacity to deplete oxygen in bottom coastal zones with possible consequences on biotopes and cultivated species: farm yields may be severely affected. This study will allow to manage more closely the commercial risk of shellfish farming at spatial and temporal scale.L’étude « Risco », labellisée par le Pôle Mer et financée par la région Bretagne, a révélé un facteur insoupçonné d’altération des résultats d’élevage ostréicole en baie de Quiberon (France, 56): l’hypoxie. Elle a ainsi fourni une explication convaincante des mortalités anormales observées sur les huîtres adultes l’été 2006. Le modèle biogéochimique appliqué sur la période 2000-2006 a mis en évidence plusieurs épisodes d’hypoxie d’intensité variable selon les années, mais très géolocalisés. Parmi eux, celui de 2006 s’est avéré exceptionnel, tant par son emprise spatiale que par son intensité. L’hypoxie de 2006 résulte de la conjonction rare de plusieurs phénomènes : (a) un upwelling local généré par des vents de nord-ouest en période de morte-eau ; (b) des eaux côtières anormalement chaudes ; (c) probablement un fort bloom estival de phytoplancton. Du fait de la stratification induite, la consommation d’oxygène au niveau du fond excède alors son renouvellement. Le secteur profond et envasé, à l’est de la zone concédée, est particulièrement affecté en raison de la géomorphologie de la baie de Quiberon. L’analyse du fonctionnement hydrodynamique à l’échelle du Mor Bras montre par ailleurs qu’il n’y a pas d’importation d’eau hypoxique depuis la baie de Vilaine, ceci quel que soit le régime de vent et de marée. La diminution de la teneur en oxygène dissous apparaît responsable de ralentissements de croissance des huîtres même en année peu hypoxique (comme 2010). C’est probablement le facteur explicatif des déficits de croissance marqués chez les huîtres au sol (par rapport aux huîtres en surélévation). En situation d’hypoxie extrême (année 2006), les huîtres des deux classes d’âge subissent des mortalités. Les huîtres d’un an paraissent plus affectées par le déficit d’oxygène, tant en croissance qu’en mortalité (étude 2010). Cette étude permet d’évaluer le risque d’hypoxie (sa probabilité d’occurrence, sa répartition géographique) et d’orienter les mesures préventives applicables en conchyliculture telles que la répartition des stocks en élevage ou l’entretien des parcs. L’incidence sur les peuplements naturels et les ressources exploitées, peut également être mieux prise en compte, à l’échelle du Mor Bras. Plus généralement, une meilleure connaissance des effets de l’hypoxie fournit des arguments en faveur du contrôle de l’eutrophisation (limitation des apports en nutriments par les bassins versants…)

On-sky results for adaptive optics control with data-driven models on low-order modes

Dedicated tip-tilt loops are commonly implemented on adaptive optics (AO) systems. In addition, a number of recent high-performance systems feature tip-tilt controllers which are more efficient than the integral action controller. In this context, Linear Quadratic Gaussian (LQG) tip-tilt regulators based on stochastic models identified from AO telemetry have demonstrated their capacity to effectively compensate for the cumulated effects of atmospheric disturbance, windshake and vibrations. These tip-tilt LQG regulators can also be periodically re-tuned during AO operations, thus allowing to track changes in the disturbances’ temporal dynamics. This paper investigates the potential benefit of extending the number of low-order modes to be controlled using models identified from AO telemetry. The global stochastic dynamical model of a chosen number of turbulent low-order modes is identified through data-driven modelling from wavefront sensor measurements. The remaining higher modes are modelled using priors with autoregressive models of order 2. The loop is then globally controlled using the optimal LQG regulator build from all these models. Our control strategy allows for combining a dedicated tip-tilt loop with a deformable mirror that corrects for the remaining low-order modes and for the higher orders altogether, without resorting to mode decoupling. Performance results are obtained through evaluation of the Strehl ratio computed on H-band images from the scientific camera, or in replay mode using on-sky AO telemetry recorded in July 2019 on the CANARY instrument

Data-based modelling of low-order modes for AO control: what do on-sky experiments tell us?

International audienceIt is well-known that data-driven models for the tip-tilt modes significantly improve the performance of Adaptive Optics (AO) systems as it allows to compensate for vibration-induced disturbances. Whether identifying from data the temporal dynamics of more modes makes an impact on the performance has been studied on-sky with the CANARY demonstrator at the William Herschel Telescope in July 2019. In this brief paper, we report on these experiments using both Strehl ratios computed from the science camera in H band or by replaying the AO telemetry data in numerical simulations. We show that Linear Quadratic Gaussian (LQG) controllers that embed a data-driven model for the low-orders (that are not limited to the tip-tilt) improve the performance of the AO for two different dynamical behaviours of the atmospheric turbulence

The M4 adaptive unit for the E-ELT

International audienceCilas proposes a M4 adaptive mirror (M4AM) that corrects the atmospheric turbulence at high frequencies and residual tip-tilt and defocus due to telescope vibrations by using piezostack actuators. The design presents a matrix of nearly 7000 actuators (hexagonal geometry, spacing equal to 29 mm) leading to a fitting error simulated by Onera reaching the fitting error goal. The mirror is held by a positioning system which ensures all movements of the mirror at low frequency and selects the focus (Nasmyth A or B) using a hexapod concept. This subsystem is fixed rigidly to the mounting system and permits mirror displacements. The M4 control system (M4CS) ensures the connection between the telescope control/monitoring system and the M4 unit - positioning system (M4PS) and piezostack actuators in particular. This subsystem is composed of electronic boards, mechanical support fixed to the mounting structure and the thermal hardware. With piezostack actuators, most of the thermal load is minimized and dissipated in the electronic boards and not in the adaptive mirror. The mounting structure (M4MS) is the mechanical interface with the telescope (and the ARU in particular) and ensures the integrity and stability of M4 unit subsystems. M4 positioning system and mounting structure are subcontracted to Amos company. We will also report on the manufacturing of the demonstration prototype that will be tested in the next phase

Les cahiers de l'école qualité en recherche et en enseignement supérieur - Numéro 6

Ce cahier regroupe les actes relatifs à la quinzième école inter-organismes « Qualité en recherche et en enseignement supérieur » organisée par l’association QuaRES à Montpellier (France), du 6 au 8 septembre 2017