An assurance level sensitive UML profile for supporting DO-178C

Several model-based approaches have been proposed to ease the process of developing certifiable safety-critical software. In this thesis, we are interested in airborne software which must comply with DO-178C standard. However, existing approaches do not provide complete support for all the activities of the software life cycle as defined by DO-178C. In this thesis, we propose an UML profile that captures the concepts of DO-178C and its supplements in order to model the evidence required for certification. This profile provides modeling constructs for the definition of a DO-178C compliant software life cycle, the specification of the software requirements, the specification of verification data and finally the specification of the traceability that is requested by DO-178C. Furthermore, this profile has the unique feature of providing means to specify the objectives and activities to be performed throughout the software life cycle depending on the targeted assurance level and applied DO-178C supplements. We implemented the proposed profile within Papyrus, an UML modeling environment. We used the profile to model a realistic example of airborne software. Specifically, we illustrated the usefulness of the profile through four use cases

Verification by Testing for Recursive Program Schemes

. In this paper 1 , we explore the testing-verification relationship with the objective of mechanizing the generation of test data. We consider program classes defined as recursive program schemes and we show that complete and finite test data sets can be associated with such classes, that is to say that these test data sets allow us to distinguish every two di#erent functions in these schemes. This technique is applied to the verification of simple properties of programs. 1 Introduction The only way to improve confidence that a program really achieves its intended purpose is to confront it with other means of expressing this purpose. Typically, such means can be properties that the program is supposed to satisfy or test data sets with oracles characterizing the expected behavior of the program. However, despite the fact that they both contribute to the same final objective, verification and testing remain two independent research areas and we haven't seen much cross-fertiliz..

Comparison of analyses of respiratory gases made with the K4b2 portable and Quark laboratory analysers in horses

Measurements of minute ventilation (VE) and expired oxygen and carbon dioxide fractions (FeO2 and FeCO2) were measured at rest and during exercise in seven warmblood horses performing two consecutive standardised incremental treadmill exercise tests at submaximal speed, using the portable K4b2 telemetric unit and the laboratory Quark metabolic cart in random order. Oxygen consumption (VO2) and carbon dioxide production (VCO2) were estimated using the Haldane equation. There were no significant differences between the measurements made with the two devices. However, VE was overestimated when the horses were cantering at 10 m/s in comparison with values available in the literature

New Metallic Stable Ion Beams for GANIL

International audienceGANIL has been producing many stable beams for nearly 40 years. Constant progress has been made in terms of intensity, stability and reliability. The intensity for some stable metallic beams now exceeds or approaches the pµA level at an energy up to 95 MeV/u: 1.14 pµA for 36S (65% enriched) at 77 MeV/u, 0.35 pµA for 58Ni (63%) at 74 MeV/u. The presentation highlights recent results obtained for 28Si, 184W and 130Te using the GANIL ‘s LCO (Large Capacity Oven) on the ECR4 ion source. To produce the tungsten beam, two injection methods were compared. For the first one, we evaporated some tungsten trioxide (WO3) with GANIL ‘s LCO. For the second one, the injection in the plasma chamber was made by using MIVOC (Metallic Ions from VOlatile compounds) with a tungsten hexacarbonyl (W(CO)6) compound. It was the first time that we used metal carbonyl compounds and the result is promising. All the tests have been qualified to obtain the level of intensity and beam stability. Theses good results led us to propose them for Physics experiments

Oxygen consumption and gait variables of Arabian endurance horses measured during a field exercise test

Reasons for performing study: Arabian horses have morphological, muscular and metabolic features designed for endurance races. Their gas exchange and gait variables were therefore measured during a field exercise test. This study presents original respiratory and locomotor data recorded in endurance horses under field conditions. Hypothesis and objectives: Respiratory gas exchange ratio (RER) of Arabian horses at the speed required to win endurance races (18 km/h for 120–160 km) are <1 and running economy (RE) is also low in order to maintain exercise intensity using aerobic metabolism for long intervals. The purpose of this study was to measure oxygen consumption and gait variables in Arabian endurance horses running in the field in order to estimate RER and RE. Materials and methods: Five Arabian horses trained for endurance racing were test ridden at increasing speeds on the field. Their speed was recorded and controlled by the rider using a GPS logger. Each horse was equipped with a portable respiratory gas analyser, which measured breath-by-breath respiratory variables and heart rate. The gait variables were recorded using tri-axial accelerometer data loggers and software for gait analysis. Descriptive statistics and linear regressions were used to analyse the speed related changes in each variable with P<0.05 taken as significant. Results: At a canter speed corresponding to endurance race winning speed (18 km/h), horses presented a VO2= 42 ± 9 ml/min/kg bwt, RER = 0.96 ± 0.10 and RE (= VO2/speed) = 134 ± 27 l/km/kg bwt. Linear relationships were observed between speed and VO2, HR and gait variables. Significant correlations were observed between VO2 and gait variables. Conclusions and potential relevance: The RER of 0.96 at winning endurance speed indicates that Arabian horses mainly use aerobic metabolism based on lipid oxidation and that RER may also be related to a good coordination between running speed, respiratory and gait parameters

Towards an understanding of coupled physical and biological processes in the cultivated Sahel - 1. Energy and water

This paper presents an analysis of the coupled cycling of energy and water by semi-arid Sahelian surfaces, based on two years of continuous vertical flux measurements from two homogeneous recording stations in the Wankama catchment, in the West Niger meso-site of the AMMA project. The two stations, sited in a millet field and in a semi-natural fallow savanna plot, sample the two dominant land cover types in this area typical of the cultivated Sahel. The 2-year study period enables an analysis of seasonal variations over two full wet–dry seasons cycles, characterized by two contrasted rain seasons that allow capturing a part of the interannual variability. All components of the surface energy budget (four-component radiation budget, soil heat flux and temperature, eddy fluxes) are measured independently, allowing for a quality check through analysis of the energy balance closure. Water cycle monitoring includes rainfall, evapotranspiration (from vapour eddy flux), and soil moisture at six depths. The main modes of observed variability are described, for the various energy and hydrological variables investigated. Results point to the dominant role of water in the energy cycle variability, be it seasonal, interannual, or between land cover types. Rainfall is responsible for nearly as much seasonal variations of most energy-related variables as solar forcing. Depending on water availability and plant requirements, evapotranspiration pre-empts the energy available from surface forcing radiation, over the other dependent processes (sensible and ground heat, outgoing long wave radiation). In the water budget, pre-emption by evapotranspiration leads to very large variability in soil moisture and in deep percolation, seasonally, interannually, and between vegetation types. The wetter 2006 season produced more evapotranspiration than 2005 from the fallow but not from the millet site, reflecting differences in plant development. Rain-season evapotranspiration is nearly always lower at the millet site. Higher soil moisture at this site suggests that this difference arises from lower vegetation requirements rather than from lower infiltration/higher runoff. This difference is partly compensated for during the next dry season. Effects of water and vegetation on the energy budget appear to occur more through latent heat than through albedo. A large part of albedo variability comes from soil wetting and drying. Prior to the onset of monsoon rain, the change in air mass temperature and wind produces, through modulation of sensible heat, a marked chilling effect on the components of the surface energy budget

Cu precipitation in electron-irradiated iron alloys for spent-fuel canisters

In this work, the Cu clustering in Fe under irradiation is investigated using experiments, cluster dynamics and atomistic kinetic Monte Carlo (AKMC) simulations. In experiments, cast iron and model FeCu alloy samples were irradiated with 2 MeV electrons for 143 h at 140 °C. The post-irradiation microstructure was characterized using atom probe tomography. Cluster dynamics and AKMC methods were used to sim- ulate the Cu clustering under the same irradiation conditions. Both simulation methods show satisfactory agreement with experiments, lending strength to the validity of the models. Finally, the Cu clustering in spent-fuel repository conditions for 10 5 years at 100 °C was simulated using both methods. The results indicate that potential hardening by Cu clustering is insignificant over 10 5 years.QC 20221006</p

Human PBMCs Form Lipid Droplets in Response to Spike Proteins

Intracellular lipid droplets (LDs) can accumulate in response to inflammation, metabolic stresses, and other physiological/pathological processes. Herein, we investigated whether spike proteins of SARS-CoV-2 induce LDs in human peripheral blood mononuclear cells (PBMCs) and in pulmonary microvascular endothelial cells (HPMECs). PBMCs or HPMECs were incubated alone or with endotoxin-free recombinant variants of trimeric spike glycoproteins (Alpha, Beta, Delta, and Omicron, 12 µg/mL). Afterward, cells were stained with Oil Red O for LDs, cytokine release was determined through ELISA, and the gene expression was analyzed through real-time PCR using TaqMan assays. Our data show that spikes induce LDs in PBMCs but not in HPMECs. In line with this, in PBMCs, spike proteins lower the expression of genes involving lipid metabolism and LD formation, such as SREBF1, HMGCS1, LDLR, and CD36. On the other hand, PBMCs exposed to spikes for 6 or 18 h did not increase in IL-1β, IL-6, IL-8, MCP-1, and TNFα release or expression as compared to non-treated controls. Thus, spike-induced LD formation in PBMCs seems to not be related to cell inflammatory activation. Further detailed studies are warranted to investigate in which specific immune cells spikes induce LDs, and what are the pathophysiological mechanisms and consequences of this induction in vivo

Cationic polycyclization of ynamides: building up molecular complexity

International audienc