R-MOM: A Component-Based Framework for Interoperable and Adaptive Asynchronous Middleware Systems

International audienceSystems of systems (SoS) are composed of subsystems such as Distributed, Information Technology, Real-Time and Embedded systems. Among distributed systems, Message- Oriented Middleware (MOM) is used by SoS in order to share status information from system elements (component, service, etc.). Often several different MOM technologies are used in one SoS, then interoperability between these MOM is a requirement. In this paper, we present R-MOM, a component-based framework for interoperable and adaptive asynchronous middleware systems. R-MOM provides a reflective component architecture where one MOM functionality is embedded into one component which is modifiable at run-time. Loosely-coupling between reflective components permits to get a fined-personalization of MOM functionalities, such as protocol, encoding rule, Quality of Services (QoS) processing, data production/consumption, description, routing and filtering. Interoperability between integrated protocol functionalities is a consequence of architecture design. R-MOM interoperates with different kinds of MOM, from distributed message queues (Java Message Service, Advanced Message Queueing Protocol, 0MQ) to content-based publish/ subscribe systems (OMG's Data Distribution Service). This paper describes the architectural concepts of the R-MOM framework, discusses its implementation, and evaluates its interoperability capability.Les Systèmes de Systèmes (SoS) sont composés de sous-systèmes tels que les systèmes de type distribué, IT, temps-réel et embarqué. Parmi les systèmes distribués, les intergiciels orientés message (MOM) sont utilisés par les SoS dans le but de partager des informations de statut des éléments du systèmes (composant, service, etc...). Souvent, plusieurs technologies MOM sont utilisées dans un même SoS, et interopérabilité entre MOM devient nécessaire. Dans ce papier, nous présentons R-MOM, un canevas basé sur l'approche composant pour les intergiciels interopérables, adaptatifs et asynchrones. R-MOM offre une architecture à composants réflexif, où une fonctionalité d'un MOM est embarquée dans un composant qui est modifiable durant son exécution. Le couplage lâche entre les composants réflexif permet de jouir d'une personnalisation fine sur les fonctionalités MOM visées, comme le protocole, la règle d'encodage, le support des qualités de service, la production et consommation, la description, le routage et le filtrage des données. L'interopérabilité entre les fonctionnalités protocolaire intégrées est une conséquence du choix de conception de l'architecture. R-MOM est interopérable avec différent types de MOM, depuis les queues de message distribué (Java Message Service, Advanced Message Queueing Protocol, 0MQ) jusqu'aux systèmes de publication/souscription basées sur le contenu (Service de Distribution de Données de l'OMG). Ce papier papier décrit les concepts d'architecture du canevas R-MOM, discute son implémentation et évalue sa capacité d'interopérabilité

Axisymmetric Tokamak Equilibria computed with a Predefined Safety Factor Profile as CHEASE input

The CHEASE code, which has been developed at the Swiss Plasma Center, generates an accurate reconstruction of toroidal magnetohydrodynamics equilibria by numerically solving the Grad-Shafranov equation. Having demonstrated its ability to achieve good convergence while remaining fast and very flexible, this code is now extensively used at different research facilities. From two input profiles, usually the pressure and the current density as well as specified boundary conditions, the code provides a complete equilibrium description which is essential for the study of tokamak plasmas. This project focuses on computing axisymmetric equilibria within ideal magnetohydrodynamics (MHD) by imposing a specific shape for the safety factor $q$. The Grad-Shafranov equation requires two free functions to be specified: one for the current density and one for the pressure (p=nT). Until now, the options in CHEASE allowed to give the pressure profile or its derivative on one hand and either $TT'$, $I^*$, $I_{\parallel}$, or $J_{\parallel}$ on the other hand. The safety factor profile was therefore a result of the computation of the equilibrium. However, this profile and its radial derivative are essential for stability and transport issues into the tokamak. The goal of the present project is thus to modify the code so as to be able to provide a safety factor profile as a CHEASE input. However, equilibria generated with the safety factor profile as input can easily lead to surface currents if strong variation of the derivative $\frac{dq}{d\rho}$ appears in the solution. It is therefore necessary to develop a method to avoid these problems, especially at the edge of the plasma. A further aim of this work is hence to demonstrate that there is no continuity problem within solutions computed with a q-profile as input. There are two ways of achieving this: one is to impose the current profile within one iteration to obtain the desired safety factor profile and the other is to impose the $TT'$ profile in the same way. The two solutions are explored in this project with the purpose to determine which one is most appropriate. Finally, the extended version of CHEASE developed in this master project is used to study the influence of safety factor profiles on the stability of tearing modes by solving the energy principle equation within the cylindrical approximation which depends directly on $q$, $q'$ and $q''

Numerical optimization of ramp-down phases for TCV and AUG plasmas

Optimization of the plasma discharge can be defined as determination of an optimal time evolution of the plasma parameters to lead a plasma to a desired state keeping it within the specific limits: physical ones (like the Greenwald density limit, low normalized beta and internal inductance values) and technical ones (like the vertical stability limit). The parameters, time-trajectories of which have to be optimized, are the ones significantly changing the plasma state, and, depending on the optimization goal, can be chosen from a wide range of plasma parameters: plasma current, plasma elongation, EC, NBI heating or current drive power, electron density, etc. Developing non-disruptive termination scenarios is important for safe operation of future tokamaks and especially for ITER since significant heat fluxes to the wall are expected during disruptions because of large amount of energy stored in burning plasmas. Therefore, the main goal of ramp-down optimization is to ramp down a plasma current as fast as possible while avoiding any disruptions. The results of the optimization problem study with the physical and technical limits is presented for TCV and AUG plasmas. The present work was done mainly with the RAPTOR code. The transport model has been extended to include a time-varying plasma equilibrium geometry, increasing the accuracy of full discharge simulations. Due to the design, the RAPTOR code is also an efficient tool for an optimization problem solving. A new ad-hoc transport model has been implemented to the RAPTOR code and tested during this work. Verification of the thermal transport model with simulation of the AUG and TCV full plasma discharges using RAPTOR will be presented

Analyses non invasives in situ des œuvres préhistoriques de la grotte de Font-de-Gaume pour une meilleure connaissance du décor pariétal polychrome et de son organisation

Dans cet article est présenté un premier bilan des résultats récents d’analyses chimiques du décor de la grotte de Font-de-Gaume. Ces données ont été obtenues lors de quatre missions de terrain entre 2013 et 2017. Un peu plus de deux cents représentations se répartissent entre un art animalier et des signes (tectiformes), dans des proportions d’environ deux tiers un tiers. L'animal le plus représenté est le bison, d'où le nom la "Caverne des bisons". Les figures ont été réalisées avec différentes techniques. On retrouve la peinture polychrome, le dessin et les gravures. L’état de conservation de la grotte étant le reflet de sa grande fragilité, les parois sont très hétérogènes, ce qui représente un réel défi analytique pour l’analyse chimique des figures dans la mesure où les analyses doivent se limiter à des approches non invasives sans contact. Ainsi, nous avons réalisé environ deux cents analyses par fluorescence X portable pour caractériser les matières colorantes. Elles ont été effectuées dans le but d'obtenir de nouveaux éléments de réponse quant à la composition chimique de la matière colorante utilisée et les techniques de réalisation de ces œuvres du Paléolithique supérieur. Nous présentons ici l'approche utilisée en se focalisant particulièrement sur les traitements des mesures effectuées. Ces premières évaluations des données ont permis d'identifier différentes matières colorantes utilisées dans la grotte de Font-de-Gaume. L'approche développée a ainsi montré son potentiel lorsqu'elle est utilisée sur un plus grand nombre de figures et en intégrant des informations complémentaires. Elle devrait permettre, à terme, d’améliorer la connaissance de ces œuvres et de leur réalisation successive dans le cas de superpositions des figures, ce qui paraît très important en l’absence d’une datation directe des œuvres pariétales de Font-de-Gaume.In this article we present a first assessment of recent results of chemical analysis of the decor of the Font-de Gaume cave. These data were obtained during four field missions between 2013 and 2017. Slightly more than two hundred representations are divided between animal art and signs (tectiforms), in proportions of about two thirds to one third. Most represented is the bison, hence the name "Bison Cave". The figures were made with different techniques. We find polychrome paintings, drawings and engravings. The state of conservation of the cave is a reflection of its great fragility. The walls are very heterogeneous, which represents a real analytical challenge for the chemical analysis of figures since the analyzes must be limited to non-invasive approaches without contact. Thus, we carried out around two hundred analyzes by portable X-ray fluorescence to characterize the coloring matters. These analyzes were carried out in order to obtain new elements of answer as for the chemical composition of the coloring matter used and the techniques of realization of these works of the Upper Paleolithic. Here we present the approach used, focusing particularly on the processing of the measurements carried out. These first evaluations of the data made it possible to identify different coloring materials used in the Font-de-Gaume cave. The approach developed has thus shown its potential, when applying on a larger number of figures and by integrating additional information. In the long term this enables improving knowledge of these works and their successive realization in the case of superimposed figures which seems very important, in the absence of a direct dating of the parietal works of Font-de-Gaume

Rapport de sondages et d'analyses, Le Kilian et les carrières anciennes de trachyte dans la Chaîne des Puys (Puy-de-Dôme)

En 2008, l'existence de carrières souterraines médiévales avait été mise en évidence dans la pente ouest du Bois de Manson qui domine la dépression du Cratère Kilian, au pied sud du puy de Dôme. En 2009-2010, des sondages et prospections ont été étendus à tout l'ensemble du Kilian de façon à préciser l'étendue et, si possible, la chronologie de son exploitation dans le passé. Ces travaux ont permis d'observer, dans le fond du cratère et sur son flanc interne ouest, des amoncellements de déblais d'un volume considérable, témoignant d'une extraction de roche à grande échelle durant le haut Moyen Âge et très probablement aussi à l'époque gallo-romaine. Une nouvelle carrière souterraine a été découverte dans la pente interne ouest du cratère. La base du remplissage de cette carrière a livré des charbons datés entre la fin du IV e siècle et le début du VI e siècle par le radiocarbone, tandis que le sommet du remplissage contenait des tessons de céramique datables, par leur typologie, de la fin du V e siècle au début du VIII e siècle. L'état actuel des investigations conduit à faire l'hypothèse que les gallo-romains ont exploité, au fond du cratère, un trachyte compact dont on ne trouve aujourd'hui que les déchets de taille, et dont les affleurements sont masqués par les déblais, tandis que les artisans du Moyen Âge ont recherché un trachyte plus tendre dans les pentes hautes du cratère. Le Kilian doit donc s'ajouter aux trois sources actuellement connues de trachyte d'oeuvre dans le passé, à savoir les volcans Sarcoui, Aumône (ou petit Suchet) et Cliersou. Dès cette découverte, en 2008, s'est posée la question de savoir quelle part éventuelle le trachyte du Kilian avait pu prendre dans la construction du temple de Mercure au sommet du puy de Dôme et dans l'agglomération gallo-romaine située au col de Ceyssat. Pour y répondre, une campagne d'analyses géochimiques et pétrographiques été engagée pour caractériser, aux fins de comparaison, non seulement les trachytes du Kilian et ceux des ruines gallo-romaines, mais, de plus, les trachytes du Cliersou, de l'Aumône et du Sarcoui. Ces analyses ont finalement montré qu'il est possible de faire une discrimination statistiquement significative entre les différents trachytes étudiés, à l'exception de ceux du couple Cliersou-Aumône dont les laves sont très peu différentes les unes des autres. Le résultat le plus remarquable est que tous les trachytes gallo-romains échantillonnés (dont 10 échantillons distincts au temple de Mercure et 10 au col de Ceyssat) se rattachent sans ambiguïté au Kilian. En toute rigueur, ces nouvelles données ne permettent pas d'exclure sans appel la possibilité d'utilisation à l'époque gallo-romaine, au temple de Mercure et au col de Ceyssat, de trachytes provenant d'autres sources que le Kilian (cas des chaperons de mur du col de Ceyssat, provenant du puy de Dôme). Cependant, il faut ajouter qu'un examen visuel des trachytes d'oeuvre dans ces deux sites, portant sur un nombre de moellons et d'éléments architecturaux bien supérieur au nombre de ceux qui ont été analysés, conduit à conclure que leur source est probablement commune. Cette conclusion est basée sur un faciès minéralogique particulier, observable à l'oeil nu ou à la loupe

Control of NTMs and integrated multi-actuator plasma control on TCV

The control of 2/1 neoclassical tearing modes (NTMs) with electron cyclotron (EC) waves has been studied both experimentally and numerically on TCV. Dynamic evolutions of NTMs along with time-varying deposition locations of the control beam have been studied in detail. The prevention of NTMs by means of preemptive EC (i.e. the control beam is switched on before the mode onset) has also been explored. A small sinusoidal sweeping with full amplitude of 0.07 (normalized to the minor radius) has been added to the control beam in two of the experiments to facilitate the comparison between NTM stabilization and prevention. It is shown that the prevention of NTMs is more efficient than NTM stabilization in terms of the minimum EC power required. Interpretative simulations with the Modified Rutherford Equation (MRE) have been performed to better quantify various effects, with coefficients well defined by dedicated experiments. Specifically, in order to obtain more insight on the dominant dependencies, a simple ad-hoc analytical model has been proposed to evaluate the time-varying classical stability index Δ' in the test discharges, based on the Δ'-triggered nature of these 2/1 NTMs. This allows simulating well the entire island width evolution with the MRE, starting from zero width and including both NTM stabilization and prevention cases for the first time. The exploration of NTM physics and control has facilitated the development of an NTM controller that is independent of the particular features of TCV and has been included in a generic plasma control system (PCS) framework. Integrated control of 2/1 NTMs, plasma β (the ratio of plasma pressure to magnetic pressure) and model-estimated safety factor q profiles has been demonstrated on TCV

PLASMA SHAPE AND FUELING DEPENDENCE ON THE SMALL ELMS REGIME IN TCV AND AUG

A series of experiments has been conducted at AUG and TCV to disentangle the role of fueling, plasma triangularity and closeness to a double null (DN) configuration for the onset of the small ELM regime. At AUG, the role of the SOL density has been revisited. Indeed, it turns out that a large density SOL is not a sufficient condition to achieve the type-II (small) ELM regime. This has been demonstrated with a constant gas fueled plasma close to DN which has been progressively shifted down, relaxing therefore the closeness to DN at constant. As the plasma is moved down, Type-I ELMs are progressively restored, finally being the unique ELM regime. It is observed that not only the pedestal top profiles are unchanged, but also the SOL profiles remained unaffected by transition from Type-II to Type-I ELMs. We conclude that the separatrix density is not the unique key parameter and it is hypothesized that the local magnetic shear, modified by the closeness to DN, could play an important role. A small ELM regime with good confinement has been achieved at TCV, a full carbon machine featuring an open divertor. A systematic scan in the fueling rate has been done for both medium and high triangularity shapes. For the latter case, a configuration close to a DN configuration, the stored energy and the pedestal top pressure increase by 5% and 30% respectively compared to the medium triangularity case. For both shapes, as the D2 fueling is increased, the Type-I ELM frequency decreases and small ELMs are observed in between large ones. Finally for the high triangularity, at the maximum fueling rate, the large ELMs are fully suppressed and only the small ELMs remain. As observed in JET and AUG, the pedestal pressure degrades with increasing fueling, up to 40% for the high triangularity scenario, although the stored energy remains almost unchanged. It is also observed that, for both shapes, the density at the separatrix increases with the fueling rate, reaching ne,sep/nG ~0.3 at ne,av/nG~0.75. The small ELM regime at TCV is associated with a coherent mode at about 30 kHz seen by the magnetic probes located at the outboard midplane. The outer target heat loads from IR tomography are reduced by more than a factor of 5 when transiting towards the small ELM regime

Towards better guidance on caseload thresholds to promote positive tuberculosis treatment outcomes:a cohort study

BACKGROUND: In low-incidence countries, clinical experience of tuberculosis is becoming more limited, with potential consequences for patient outcomes. In 2007, the Department of Health released a guidance 'toolkit' recommending that tuberculosis patients in England should not be solely managed by clinicians who see fewer than 10 cases per year. This caseload threshold was established to try to improve treatment outcomes and reduce transmission, but was not evidence based. We aimed to assess the association between clinician or hospital caseload and treatment outcomes, as well as the relative suitability of making recommendations using each caseload parameter. METHODS: Demographic and clinical data for tuberculosis cases in England notified to Public Health England's Enhanced Tuberculosis Surveillance system between 2003 and 2012 were extracted. Mean clinician and hospital caseload over the past 3 years were calculated and treatment outcomes grouped into good/neutral and unfavourable. Caseloads over time and their relationship with outcomes were described and analysed using random effects logistic regression, adjusted for clustering. RESULTS: In a fully adjusted multivariable model (34,707 cases)there was very strong evidence that management of tuberculosis by clinicians with fewer than 10 cases per year was associated with greater odds of an unfavourable outcome compared to clinicians who managed greater numbers of cases (cluster-specific odds ratio, 1.14; 95 % confidence interval, 1.05-1.25; P = 0.002). The relationship between hospital caseload and treatment outcomes was more complex and modified by a patient's place of birth and ethnicity. The clinician caseload association held after adjustment for hospital caseload and when the clinician caseload threshold was reduced down to one. CONCLUSIONS: Despite the relative ease of making recommendations at the hospital level and the greater reliability of recorded hospital versus named clinician, our results suggest that clinician caseload thresholds are more suitable for clinical guidance. The current recommended clinician caseload threshold is functional. Sensitivity analyses reducing the threshold indicated that clinical experience is pertinent even at very low average caseloads, which is encouraging for low burden settings