Une Approche Incrémentale pour Adapter des Blocs SysML

International audienceLe développement des systèmes complexes et hétérogènes revêt un intérêt grandissant dans le milieu industriel. Pour améliorer la qualité de développement de tels systèmes, il faut s'appuyer sur une véritable approche qui non seulement combine des langages de spécification de haut niveau et des langages formels permettant la vérification, mais aussi, elle doit permettre une décomposition du système en un ensemble de composants. Ceci implique la définition de méthodes pour assembler et adapter ces composants. Des travaux existants dans font référence au problème d'adaptation de composants. D'une part, nous nous appuyons sur le langage SysML pour modéliser l'architecture et le comportement des composants, et d'autre part, nous faisons appel au formalisme des automates d'interface pour modéliser les interactions entre les blocs réutilisés et générer les protocoles d'interaction des blocs adaptateurs

SysML Model-Driven Approach to Verify Blocks Compatibility

International audienceIn the component paradigm, the system is seen as an assembly of heterogeneous components, where the system reliability depends on these components compatibility. In our approach, we focus on verifying compatibility of components modelled with SysML diagrams. Thus, we model component interactions with sequence diagrams (SDs) and components with SysML blocks. The SDs constitute a good start point for compatibility verification. However, this verification is still inapplicable directly on SDs, because they are expressed in informal language. Thus, to apply a verification method, it is necessary to translate the SDs into formal models, and then verify the wanted properties. In this paper, we propose a high-level model-driven approach which consists of an ATL grammar that automates the transformation of SDs into interface automata. Also, to allow an easy use of Ptolemy tool to verify properties on automata, we have proposed some Acceleo templates, which generate the Ptolemy entry specification

Gravity-induced ischemia in the brain and prone positioning for COVID-19 patients breathing spontaneously: still far from the truth!

International audienceGlobal mindset is usually considered as a positive skill or resource that helps individuals and companies succeed internationally. We argue that it is also a collective scheme of thought that brings some actors together and sets others apart. We investigate this perspective through a qualitative study of French MNC managers, internationalisation support providers, and SME owners and managers attempting to create or grow their business in China. We reveal that global mindset is a double‐edged concept: it is not solely an instrument for integration, but also a doxa, a particular viewpoint imposed to identify and reject outsiders through symbolic struggles. This alternative conceptualisation is necessary to rethink the social forces at work in the field of international business. It is also necessary to encourage educators and practitioners to acknowledge the struggles that result from the imposition of certain views and behaviours and to adapt education, support and training programs accordingly.L’objectif de cet article est de comprendre la dynamique des compétences interculturelles individuelles et collectives des prestataires dans l’expérience de service du client. Les résultats de l’étude de cas d’une business unit française prestataire de services linguistiques qui excelle en la matière montrent qu’une articulation eff icace des deux niveaux de compétence assure la satisfaction des clients et contribue à la compétitivité de l’entreprise

Clinical characteristics and outcomes of critically ill COVID-19 patients in Sfax, Tunisia

Background Africa, like the rest of the world, has been impacted by the coronavirus disease 2019 (COVID-19) pandemic. However, only a few studies covering this subject in Africa have been published. Methods We conducted a retrospective study of critically ill adult COVID-19 patients—all of whom had a confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection—admitted to the intensive care unit (ICU) of Habib Bourguiba University Hospital (Sfax, Tunisia). Results A total of 96 patients were admitted into our ICU for respiratory distress due to COVID-19 infection. Mean age was 62.4±12.8 years and median age was 64 years. Mean arterial oxygen tension (PaO2)/fractional inspired oxygen (FiO2) ratio was 105±60 and ≤300 in all cases but one. Oxygen support was required for all patients (100%) and invasive mechanical ventilation for 38 (40%). Prone positioning was applied in 67 patients (70%). Within the study period, 47 of the 96 patients died (49%). Multivariate analysis showed that the factors associated with poor outcome were the development of acute renal failure (odds ratio [OR], 6.7; 95% confidence interval [CI], 1.75–25.9), the use of mechanical ventilation (OR, 5.8; 95% CI, 1.54–22.0), and serum cholinesterase (SChE) activity lower than 5,000 UI/L (OR, 5.0; 95% CI, 1.34–19). Conclusions In this retrospective cohort study of critically ill patients admitted to the ICU in Sfax, Tunisia, for acute respiratory failure following COVID-19 infection, the mortality rate was high. The development of acute renal failure, the use of mechanical ventilation, and SChE activity lower than 5,000 UI/L were associated with a poor outcome

Adptation des Blocs sysML et verification des propriétés temporelles

The work presented in this thesis takes place in the component-based development domain, it is a contribution to the specification,adaptation and verification of component-based systems. The main purpose of this thesis is the proposition of a formal approach tobuild incrementally complex systems by assembling and adapting a set of components, where their structure and behaviour are modelledusing SysML diagrams. In the first stage, we have defined a meta-model driven approach which is based on meta-modelling and modelstransformation, to verify the compatibility of blocks having their interaction protocols modelled using SysML sequence diagrams. To verifytheir compatibility, we perform a transformation into interface automata (IAs), and we base on the optimistic approach defined on IAs. Thisapproach consider that two components are compatible if there is a suitable environment with which they can interact correctly. Afterthat, we have proposed to benefit from the hierarchy, that may be present in the interaction protocol models of the blocks, to alleviate theverification of blocks compatibility. In the next stage, we have taken into consideration the problem of names mismatches of type one2onebetween services of blocks. At this stage, an adapter is generated for a set of reused blocks which have their interaction protocols modelledformally by interface automata. The generation of the adapter is guided by the specification of the parent block which is made initiallyby the designer. Our approach is completed by a verification phase which allows us to verify SysML requirements, expressed formallyby temporal properties, on SySML blocks. In this phase, we have exploited only the generated adapters to verify the preservation of therequirements initially satisfied by the reused blocks. Thus, our approach intends to give more chance to avoid the state space explosionproblem during the verification. In the same context, where we have a set of reused blocks and the specification of their parent blocks, wehave proposed to use coloured Petri nets (CPNs) to model the blocks interactions and to generate adapters that solve more type of problems.In this case the adapter can solve the problem of livelock by enabling the reordering of services calls.Le travail présenté dans cette thèse a lieu dans le domaine de développement basé sur les composants, il est une contribution à laspécification, l'adaptation et la vérification des systèmes à base de composants. Le but principal de cette thèse est la proposition d'uneapproche formelle pour construire progressivement des systèmes complexes en assemblant et en adaptant un ensemble de composants,où leur structure et leur comportement sont modélisés à l'aide de diagrammes SysML. Dans la première étape, nous avons défini uneapproche basée sur la méta-modélisation et la transformation des modèles pour vérifier la compatibilité des blocs ayant leurs protocolesd'interaction modélisés à l'aide de diagrammes de séquence SysML. Pour vérifier leur compatibilité, nous effectuons une transformationen automates d'interface (IAs), et nous utilisons l'approche optimiste définie sur les IA. Cette approche considère que deux composantssont compatibles s'il existe un environnement approprié avec lequel ils peuvent interagir correctement. Après cela, nous avons proposéde bénéficier de la hiérarchie, qui peut être présente dans les modèles de protocole d'interaction des blocs, pour alléger la vérification dela compatibilité des blocs. Dans l'étape suivante, nous avons pris en considération le problème des incohérences de noms de type one2oneentre les services des blocs. A ce stade, un adaptateur est généré pour un ensemble de blocs réutilisés qui ont leurs protocoles d'interactionmodélisés formellement par des automates d'interface. La génération de l'adaptateur est guidée par la spécification du bloc parent qui estfaite initialement par le concepteur. Notre approche est complétée par une phase de vérification qui nous permet de vérifier les exigencesSysML, exprimées formellement par les propriétés temporelles, sur les blocs SySML. Dans cette phase, nous avons exploité uniquementles adaptateurs générés pour vérifier la préservation des exigences initialement satisfaites par les blocs réutilisés. Ainsi, notre approchea l'intention de donner plus de chance d'éviter le problème de l'explosion de l'espace d'état au moment de la vérification. Dans le mêmecontexte, où nous avons un ensemble de blocs réutilisés et la spécification de leurs blocs parents, nous avons proposé d'utiliser des réseauxde Petri colorés (CPN) pour modéliser les interactions des blocs et générer des adaptateurs qui résolvent plus de types de problèmes. Dansce cas, l'adaptateur peut résoudre le problème de blocage en permettant le ré-ordonnancement des appels de services

A Model-Driven Approach to Adapt SysML Blocks

International audienceReusing and adapting existing components is the central topic of component-based development. The major differences between the existing approaches concern the models used to represent the components and the detail given to generate the adapters. In this paper, we present our approach which bases on the hierarchy to generate the adapters. Our components are modelled using SysML blocks and their interaction protocols are modelled using SysML Sequence Diagrams (SDs). We have used coloured Petri nets as formal model to define the adaptation rules, and we have based on meta-modelling and model transformation to implement these rules. We illustrate our approach through a case study

Exploitation de la Hiérarchie pour la Vérification de la Compatibilité entre les Blocs SysML

International audienceLe développement de systèmes à base de composants consiste en l’assemblage d’un ensemble d’unités de base qui répondent chacune à une partie des exigences du système. Cette démarche permet la réduction du coût de développement.Cependant, l’opération d’assemblage impose l’adoption d’une approche de vérification qui doit être complète et moins coûteuse. Dans ce papier, nous proposons une approche formelle de vérification de la compatibilité de blocs SysML, en vue d’étudier la possibilité de leur assemblage. Principalement, une spécification SysML d’un système consiste à représenter sa structure sous forme d’un ensemble de blocs en interaction, cette interaction peut être modélisée par des modèles qui exposent un certain niveau de hiérarchie. Notre approche propose de profiter de la hiérarchie présente dans les modèles SysML ainsi que dans les automates afin d’alléger la vérification de la compatibilité des blocs SysML

Compatibility Verification of SysML Blocks Using Hierarchical Interface Automata

International audienceThe objective of this paper is to propose an approach to formalize and verify the compatibility between SysML blocks, and to help in making decision about the possibility of assembling these blocks. We specify the architecture of the system using SysML internal block diagrams. To model the interaction between blocks with a convivial manner, we propose HPSM (Hierarchical Protocol State Machine) diagram. In order to permit the verification of such interactions, we perform a translation of HPSMs into HIA-ILTs (Hierarchical Interface Automata with Inter-Level Transitions), a variant of interface automata (IA) which we propose for this purpose. Our major objective is to benefit from the hierarchy which is present in HIA-ILTs. Thus, we have adapted the existing approaches of compatibility verification based on IAs to be applicable on the HIA-ILTs. However, in order to avoid the flattening of the entire HIA-ILT, we propose a preliminary phase that allows selecting the composite states to flatten. The aim behind this is to alleviate the verification phase. Our approach is illustrated by a case study, where we demonstrate the expressiveness of the HPSM and the HIA-ILT, and we show how the hierarchy and the abstraction help to reduce the complexity of verification

Pulmonary embolism in intensive care unit: Predictive factors, clinical manifestations and outcome

<b>Objective</b> :<b> </b> To determine predictive factors, clinical and demographics characteristics of patients with pulmonary embolism (PE) in ICU, and to identify factors associated with poor outcome in the hospital and in the ICU. <b> Methods</b> :<b> </b> During a four-year prospective study, a medical committee of six ICU physicians prospectively examined all available data for each patient in order to classify patients according to the level of clinical suspicion of pulmonary thromboembolism. During the study periods, all patients admitted to our ICU were classified into four groups. The first group includes all patients with confirmed PE; the second group includes some patients without clinical manifestations of PE; the third group includes patients with suspected and not confirmed PE and the fourth group includes all patients with only deep vein thromboses (DVTs) without suspicion of PE. The diagnosis of PE was confirmed either by a high-probability ventilation/perfusion (V/Q) scan or by a spiral computed tomography (CT) scan showing one or more filling defects in the pulmonary artery or in its branches. The diagnosis was also confirmed by echocardiography when a thrombus in the pulmonary artery was observed. <b> Results</b> :<b> </b> During the study periods, 4408 patients were admitted in our ICU. The diagnosis of PE was confirmed in 87 patients (1.9&#x0025;). The mean delay of development of PE was 7.8 &#177; 9.5 days.<b> </b> On the day of PE diagnosis, clinical examination showed that 50 patients (57.5&#x0025;) were hypotensive, 63 (72.4&#x0025;) have SIRS, 15 (17.2&#x0025;) have clinical manifestations of DVT and 71 (81.6&#x0025;) have respiratory distress requiring mechanical ventilation. In our study, intravenous unfractionated heparin was used in 81 cases (93.1&#x0025;) and low molecular weight heparins were used in 4 cases (4.6&#x0025;).<b> </b> The mean ICU stay was 20.2 &#177; 25.3 days and the mean hospital stay was 25.5 &#177; 25 days. The mortality rate in ICU was 47.1&#x0025; and the in-hospital mortality rate was 52.9&#x0025;.<b> </b> Multivariate analysis showed that factors associated with a poor prognosis in ICU are the use of norepinephrine and epinephrine<b> . </b> Furthermore, factors associated with in-hospital poor outcome in multivariate analysis were a number of organ failure associated with PE &#8805; 3. Moreover, comparison between patients with and without pe showed that predictive factors of pe are: acute medical illness, the presence of meningeal hemorrhage, the presence of spine fracture, hypoxemia with PaO₂ /FiO₂ ratio &#60; 300 and the absence of pharmacological prevention of venous thromboembolism. <b>Conclusion</b> :<b> </b> Despite the high frequency of DVT in critically ill patients, symptomatic PE remains not frequently observed, because systematic screening is not performed. Pulmonary embolism is associated with a high ICU and in-hospital mortality rate. Predictive factors of PE are acute medical illness, the presence of meningeal hemorrhage, the presence of spine fracture, hypoxemia with PaO₂ /FiO₂ &lt; 300 and the absence of pharmacological prevention of venous thromboembolism