Using formal methods in safety-critical interactive system design : from architecture-based approaches to tool-based development

10p.International audienceAlthough formal methods are increasingly used by researchers in HCI, their usage in actual interactive developments has not been put in practice. In this article, we describe our experience with a specific formal method -the B method- from two viewpoints. On the one hand, we demonstrate how it is possible to use formal methods on real development, from specification to actual code. Our case study concerns a real-time functional core. Doing so, we notice that some HCI concepts, such as architecture models, may have to be adapted or recreated. On the other hand, we show how it is possible to make formal methods easier to use by the way of a complete integration into HCI tools. We conclude in eliciting the lessons learned from this experience

Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.

Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707

Vers une approche sûre du développement des Interfaces Homme-Machine

Human-Computer Interfaces (HCI) represent an essential part in most computing systems. Resorting to specification, development, checking, validation models and notations from interactive application's description is becoming necessary to ensure that the system perfectly meets the properties that define usability.Nowadays, we consider that properties can be checked following two approaches: one based on formal developments and the second one is tool based. In spite of great progress, none of them emerged.In this context, we propose two new approches allowing a safe Human-Computer interface development, based on a single formal method (B method).The first approach, based on formal developments, permits the integration of HCI notations and heterogeneous techniques into a single forma method (B method) in order to express, check and validate interactive system properties.The second one, based on tools definitions (SUIDT) allows creating an interactive dialog between the formally-developed functional core using B and an user interface. Moreover, the latter approach ensures properties what are expressed both into the functional core and by the user's needs.Les interfaces homme-machine (IHM) constituent une part indispensable dans la quasi-totalité des systèmes informatiques. Le recours à des notations de description des IHM, et à des modèles de spécification, de développement, de vérification et de validation devient indispensable pour assurer que le système satisfait les propriétés définissant la notion d'utilisabilté. Aujourd'hui, on peut considérer que deux approches exploitant les modèles du domaine de l'IHM peuvent être mises en parallèle pour la vérification de propriétés : les approches fondées sur le développement formel et les approches fondées sur la définition d'outils. Malgré des avancées intéressantes, aucune d'elles n'est encore parvenue à s'imposer. Nous proposons dans cette thèse deux nouvelles approches permettant le développement sûr d'interfaces homme-machine, fondées sur une même méthode formelle (la méthode B). La première fondée sur le développement formel permet, d'intégrer des notations et des techniques hétérogènes du domaine de l'IHM dans une seule et unique méthode formelle (la méthode B), afin d'exprimer, vérifier et valider des propriétés du système interactif. La seconde, fondée sur la définition d'outils, (SUIDT), permet de concevoir de manière interactive le dialogue entre un noyau fonctionnel développé formellement en B et une présentation graphique de l'interface, tout en garantissant le respect des propriétés exprimées à la fois dans le noyau fonctionnel et au niveau des tâches de l'utilisateur

Vers une approche sûre du développement des Interfaces Homme-Machine

Les interfaces homme-machine (IHM) constituent une part indispensable dans la quasi-totalité des systèmes informatiques. Le recours à des modèles de spécification, de développement, de vérification et de validation devient indispensable pour assurer les propriétés de l'IHM. Aujourd'hui, on peut considérer que deux approches (approches fondées sur le développement formel, approches fondées sur la définition d'outils) exploitant les modèles du domaine de l'IHM peuvent être mises en parallèle pour la vérification des propriétés. Malgré des avancées intéressantes, aucune d'elles n'est encore parvenue à s'imposer. Nous proposons dans cette thèse deux nouvelles approches permettant le développement sûr d'IHM, fondées sur une même méthode formelle (la méthode B). La première intègre des techniques hétérogènes du domaine de l'IHM, afin d'exprimer, vérifier et valider formellement des propriétés. La seconde, fondée sur les outils (SUIDT), conçoit de manière interactive le dialogue entre un noyau fonctionnel développé formellement et une présentation graphique.Human-Computer Interfaces (HCI) represent an essential part in most computing systems. Resorting to specification, development, checking, validation models is becoming necessary to ensure that the system perfectly meets the HCI's properties. Nowadays, we consider that properties can be checked following two approaches one based on formal developments and the second one is tool based. In spite of great progress, none of them emerged. In this context, we propose two new approaches allowing a safe HCI development, based on a single formal method (B method). The first approach, based on formal developments, permits the integration of HCI heterogeneous techniques in order to express, check and validate interactive system properties. The second one, based on tools definitions (SUIDT) allows creating an interactive dialog between the formally-developed functional core and an user interface. Moreover, the latter approach ensures properties what are expressed both into the functional core and by the user's needs.POITIERS-BU Sciences (861942102) / SudocSudocFranceF

Integrating formal approaches in Human-Computer Interaction

Abstract: Formal methods are increasingly used by HCI researchers. Nevertheless, their usage in actual interactive developments is not so common. In this paper, we describe the use of a specific formal method from two viewpoints. On the one hand, we demonstrate how it is possible to use a formal method on real development from specification to actual code. Doing so, we notice that HCI concepts, such as architecture models, may have to be adapted. On the other hand, we show how it is possible to bring more usability to formal methods by the way of a complete integration into HCI tools. We conclude in eliciting the lessons learned from these works

Abstract Using Formal Methods in Safety-Critical Interactive System Design: from Architecture-based Approaches to Tool-based Development

Although formal methods are increasingly used by researchers in HCI, their usage in actual interactive developments has not been put in practice. In this article, we describe our experience with a specific formal method –the B method – from two viewpoints. On the one hand, we demonstrate how it is possible to use formal methods on real development, from specification to actual code. Our case study concerns a real-time functional core. Doing so, we notice that some HCI concepts, such as architecture models, may have to be adapted or recreated. On the other hand, we show how it is possible to make formal methods easier to use by the way of a complete integration into HCI tools. We conclude in eliciting the lessons learned from this experience.

K-MADe : un environnement pour le noyau du modèle de description de l'activité

International audienc

Fabrication of GaAs nanowires and GaAs-Si axial heterostructure nanowires on Si (100) substrate for new applications

International audienceThe integration of III-V semiconductor nanowires on Si for nanoelectronics or nanophotonics devices is still a challenge. The monolithic integration of GaAs nanowires on silicon (100) by top-down approach enables new possibilities for the design and devices fabrication. We demonstrate the fabrication of GaAs-Si(100) nanowires array by plasma etching