Identification Model of the Object Oriented Technology risks, for Avionics Certification

International audienceThe introduction of any new technology in an existing industrial process has a dual effect: on the one hand, it is expected to bring some well-identified benefits, but on the other hand, it also brings a certain number of new risks. It is the role and responsibility of decision makers, designers, and developers to estimate and balance these two aspects, taking into account the very specific characteristics of their industrial domain. In the domain of software systems, for instance, object-oriented technologies have been demonstrated to increase software quality and productivity, but they simultaneously bring some specific risks that must be carefully characterized and handled, especially when they are integrated in the development of software applications for critical systems. In the avionics domain, the OOTiA document proposes a first and informal identification of some of these risks. However this identification process misses the formal background that would guarantee its consistency and completeness. In this paper, we suggest to fill this gap by considering the management of software risk as a specific case of industrial risk management. To achieve this goal, we propose a generic model for the identification of software risks. This model provides the information required by the subsequent phases of risk management: risk estimation, risk acceptance, and risk mitigation

From atomic attrition to mild wear at multi-asperity interfaces:The wear of <i>hard</i> Si₃N₄ repeatedly contacted against <i>soft</i> Si

Wear causes surfaces to be irreversibly damaged, thereby incurring significant economic cost, for instance in the semiconductor industry. Much progress has been made in describing wear at single asperity interfaces between silicon based materials (Si, SiOx, Si3N4), translating the fundamental understanding of wear into wear predictions and control over wear. Yet, predicting and controlling wear at industrially relevant multi-asperity interfaces remains a challenge, especially when considering the wear of the harder material subjected to repeated, nanometric scale displacement. We studied pre-sliding Si3N4-on-Si wear using the atomic force microscopy topography difference method and showed that the harder Si3N4 wears through either atomic attrition or ductile removal enhanced by subsurface damage, depending on the magnitude of the local Si3N4-on-Si contact pressure. Our methods and results bridge fundamental insight into wear based on nanoscale studies to industrial applications.</p

Scavenging of aerosol particles by rain in a cloud resolving model

International audienceWe describe a below-cloud scavenging module of aerosol particles by raindrops for use in a three-dimensional mesoscale cloud resolving model. The rate of particle removal is computed by integrating the scavenging efficiency over the aerosol particle and the drop size distributions. Here the numerical integration is performed accurately with a Gauss quadrature algorithm. The efficiency of the scavenging module is partially confirmed with experimental data. More interestingly, it is illustrated by two numerical experiments: the simulation of a forced convective circulation in a tropical cloudy boundary layer and a two-dimensional simulation of an African squall line. The results show a very selective wet removal of the aerosol particles which clearly depends on the mode radius, the width and the vertical profile of concentration. Furthermore, the squall line case shows the importance of resolving internal circulations to redistribute layers of aerosol particles in order to improve estimates of particle removal by below-cloud scavenging

Early Localization of Bronchogenic Carcinoma

The performance of a fluorescence imaging device was compared with conventional white-light bronchoscopy in 100 patients with lung cancer, 46 patients with resected stage I non-small cell lung cancer, 10 patients with head and neck cancer, and 67 volunteers who had smoked at least 1 pack of cigarettes per day for 25 years or more. Using differences in tissue autofluorescence between premalignant, malignant, and normal tissues, fluorescence bronchoscopy was found to detect significantly more areas with moderate/severe dysplasia or carcinoma in situ than conventional white-light bronchoscopy with a similar specificity. Multiple foci of dysplasia or cancer were found in 13–24% of these individuals. Fluorescence bronchoscopy may be an important adjunct to conventional bronchoscopic examination to improve our ability to detect and localize premalignant and early lung cancer lesions

Interactive segmentation and analysis of historical printed documents

In this paper, we first precise the main error sources from classical methods of structural page layout analysis based on a study of the specificity of old printed books. We show that each type of methods (bottom-up and top-down) provides different kinds of information that should not be ignored to obtain both a generic method and good segmentation results. Then, we propose to use a hybrid segmentation algorithm. We build two maps : a shape map that focuses on connected components and a background map that provides information on white areas corresponding to block separation in the page. Then, using this first segmentation, a classification of the extracted blocks can be achieved according to scenarios built by the user. These scenarios are defined very simply during an interactive stage allowing the users to produce processing sequences adapted to the different kinds of images they can meet and to their needs. The method gives very good results while the setting of parameters is easy and not sensitive to low variations.Après avoir caractérisé les spécificités de mise en page dans les ouvrages imprimés anciens, nous montrons par une campagne d’expérimentations que les méthodes ascendantes et descendantes d’extraction de la structure physique apportent des informations différentes qu’il ne faut pas ignorer lorsque l’on désire segmenter de manière optimale des documents anciens. Les tests réalisés mettent également en évidence les sources d’erreurs des méthodes traditionnelles. Partant de ces constatations, notre proposition consiste à utiliser un algorithme de segmentation hybride basé sur la construction de deux représentations de l’image : une carte des formes qui se focalise sur les composantes connexes présentes dans l’image et une carte du fond qui fournit de l’information sur les espaces blancs séparant les blocs constituant la page. Ensuite, sur la base de la segmentation obtenue à l’aide de cette méthode, une classification des blocs extraits peut être réalisée selon des scénarios que l’utilisateur met en place en fonction de ses besoins. Ces scénarios sont définis simplement grâce à une phase d’interaction entre l’utilisateur et le système et permettent de concevoir des chaînes de traitements adaptées aux différents types d’images que l’on peut rencontrer

A star-shaped triphenylamine π-conjugated system with internal charge-transfer as donor material for hetero-junction solar cells

Introduction of dicyanovinyl groups on a triphenylamine-based conjugated system leads to an intramolecular charge transfer which extends the spectral response and raises the open-circuit voltage of the resulting hetero-junction solar cells

Capillary adhesion governs the friction behavior of electrochemically corroded polycrystalline diamond

The friction behavior of rough polycrystalline diamond (PCD) surfaces is important in many applications and devices that are required to operate in various harsh environments and it can be argued that a thorough understanding of the friction behavior is essential to the application performance. However, the interplay between electrochemical corrosion, capillary adhesion and friction behavior of PCD in multi-asperity contacts is still poorly understood. In this work, we quantify the interfacial capillary adhesion at contact interfaces and its effect on the friction response, between a colloidal microsphere and rough PCD films before and after electrochemical corrosion, for water-immersed, low RH, and humid air conditions. For these multi-asperity contacts, we demonstrate how electrochemical corrosion influences the surface hydrophilicity of the PCD surfaces, and how capillary adhesion due to water condensation contributes to the friction force. We estimate the capillary forces from both the microscopic lateral force experiments and elastoplastic boundary element method (BEM) contact calculations. The combined results indicate strongly that the observed increase in friction force on electrochemically-corroded PCD surfaces is governed by enhanced capillary adhesion at the contact interface, as affected by surface hydrophilicity and environmental humidity

3D-conjugated systems based on oligothiophenes and phosphorus nodes

3D-conjugated systems based on oligothiophene segments grafted on a phosphorus or on a phosphine oxide node have been synthesized. Under Stille coupling conditions, bromide terminated thienyl phosphine derivatives undergo a breaking of the phosphorus–carbon bond attributed to a ligand exchange with the Pd catalyst. The electronic properties of the new compounds have been analyzed by UV-vis and fluorescence spectroscopy and cyclic voltammetry

A tailored hybrid BODIPY–oligothiophene donor for molecular bulk heterojunction solar cells with improved performances

Fixation of a 5-hexyl-2,2′-bithienyl unit on a conjugated BODIPY donor increases the conversion efficiency of the resulting molecular bulk heterojunction solar cells from 1.30 to 2.20%

Femtosecond laser impact on calcium phosphate bioceramics assessed by micro-Raman spectroscopy and osteoblastic behaviour

The present work is an investigation of the biological response to the presence of grooves 3 µm deep, 15 µm wide and spaced by 100 µm, produced with femtosecond laser on ß-tricalcium phosphate (ß-TCP). The heat affected zone generated by the laser irradiation was investigated. Micro-Raman spectroscopy showed a transformation from ß-TCP phase into a-TCP phase, localised inside the grooves. The X Ray Diffraction analyses, correlated with micro-Raman data, confirmed that the use of femtosecond pulsed laser enables to limit the thermal impact. A selection of optimised process parameters allowed to obtain ß-TCP micro-patterned surfaces avoiding any phase transformation. The increase of the wettability with the micro-patterning, compared to smooth surfaces, was highlighted. An improvement of the osteoblastic proliferation was also demonstrated. Finally, the tendency of cell elongation along the grooves direction showed the ability of osteoblastic cells to adapt their morphology to the support topography on which they grow.The authors are grateful to the JECS Trust for funding the visit of Marie Lasgorceix to the Laboratory INEB (Contract N°2015106). Marie Lasgorceix also acknowledges the Walloon Region for financial support, within the “BEWARE” program (convention n°1510392) co-funded by Wallonia and European Union (FP7 – Marie Curie Actions) . The authors are grateful to Dr Sylvain Desprez (Materia Nova, Mons, Belgium) for micro-Raman analyses. This publication is based on the work of COST Action MP1301, funded by COST (European Cooperation in Science and Technology) www.cost.eu