Safety Evaluation of Critical Applications Distributed on TDMA-Based Networks

Critical embedded systems have to provide a high level of dependability. In automotive domain, for example, TDMA protocols are largely recommended because of their deterministic behavior. Nevertheless, under the transient environmental perturbations, the loss of communication cycles may occur with a certain probability and, consequently, the system may fail. This paper analyzes the impact of the transient perturbations (especially due to Electromagnetic Interferences) on the dependability of systems distributed on TDMA-based networks. The dependability of such system is modeled as that of "consecutive-k-out-of-n:F" systems and we provide a efficient way for its evaluation

Approche pluridisciplinaire de la sûreté des systèmes

Colloque avec actes et comité de lecture.Nous présentons un sous-ensemble des travaux développés dans le cadre d'un Programme Fédérateur de Recherches sur la sûreté des systèmes industriels. Ils se placent dans le cadre du cycle spécification conception développement de systèmes de commande. l'objectif de ce programme est de rapprocher les équipes de différents laboratoires travaillant sur certains étapes de ce cycle afin d'intégrer au mieux la sûreté de fonctionnement du système

Quantitative Evaluation of the Safety of X-by-Wire Architecture subject to EMI Perturbations

The X-by-Wire systems in cars can only be accepted if they provide at least the same dependability than the traditional ones. In this paper we propose a new approach to evaluate the impact of the EMI perturbations on the dependability of an X-by-Wire architecture. The considered X-by-Wire architecture is distributed around a TDMA-like communication protocol. So a perturbation causes the loss of a communication cycle with a certain probability. The vehicle level failure is then defined as the consecutive loss of a certain number of communication cycles. Its reliability is modeled as that of the well-known consecutive-k-out-of-n:F systems. A case study, together with the EMI perturbations collected on the roads in France, is used to illustrate our approach

Optimal Control with Packet Drops in Networked Control Systems

International audienceThe stability and performance of a networked control system are strongly influenced by the network delay and packet drops. In this paper, we consider that late arrived sampling data are dropped, so that we only focus on the analysis of the impact of packet drop sequences on the control loop stability and performance. For any dropping sequence specified by (m,k)-firm model, and considering a simple mono-variable linear system with a proportional controller and zero control action in case of sampling data drop, we derived the stability conditions based on the upper bound of the plant state variance. It has been shown that the stability only depends on the values of m and k but not the pattern of the dropping sequence. In case of network overload, this gives much freedom to actively dropping some packets while still keeping the system stable. An analytic method to determine the optimal control gain for any given packet drop pattern is also derived, providing thus a guideline for optimal control and network resource scheduling co-design

Creatine and guanidinoacetate reference values in a French population

Creatine and guanidinoacetate are biomarkers of creatine metabolism. Their assays in body fluids may be used for detecting patients with primary creatine deficiency disorders (PCDD), a class of inherited diseases. Their laboratory values in blood and urine may vary with age, requiring that reference normal values are given within the age range. Despite the long known role of creatine for muscle physiology, muscle signs are not necessarily the major complaint expressed by PCDD patients. These disorders drastically affect brain function inducing, in patients, intellectual disability, autistic behavior and other neurological signs (delays in speech and language, epilepsy, ataxia, dystonia and choreoathetosis), being a common feature the drop in brain creatine content. For this reason, screening of PCDD patients has been repeatedly carried out in populations with neurological signs. This report is aimed at providing reference laboratory values and related age ranges found for a large scale population of patients with neurological signs (more than 6 thousand patients) previously serving as a background population for screening French patients with PCDD. These reference laboratory values and age ranges compare rather favorably with literature values for healthy populations. Some differences are also observed, and female participants are discriminated from male participants as regards to urine but not blood values including creatine on creatinine ratio and guanidinoacetate on creatinine ratio values. Such gender differences were previously observed in healthy populations; they might be explained by literature differential effects of testosterone and estrogen in adolescents and adults, and by estrogen effects in prepubertal age on SLC6A8 function. Finally, though they were acquired on a population with neurological signs, the present data might reasonably serve as reference laboratory values in any future medical study exploring abnormalities of creatine metabolism and transport

Overview of the current use of levosimendan in France: a prospective observational cohort study

Abstract Background Following the results of randomized controlled trials on levosimendan, French health authorities requested an update of the current use and side-effects of this medication on a national scale. Method The France-LEVO registry was a prospective observational cohort study reflecting the indications, dosing regimens, and side-effects of levosimendan, as well as patient outcomes over a year. Results The patients included ( n = 602) represented 29.6% of the national yearly use of levosimendan in France. They were treated for cardiogenic shock ( n = 250, 41.5%), decompensated heart failure ( n = 127, 21.1%), cardiac surgery-related low cardiac output prophylaxis and/or treatment ( n = 86, 14.3%), and weaning from veno-arterial extracorporeal membrane oxygenation ( n = 82, 13.6%). They received 0.18 ± 0.07 µg/kg/min levosimendan over 26 ± 8 h. An initial bolus was administered in 45 patients (7.5%), 103 (17.1%) received repeated infusions, and 461 (76.6%) received inotropes and or vasoactive agents concomitantly. Hypotension was reported in 218 patients (36.2%), atrial fibrillation in 85 (14.1%), and serious adverse events in 17 (2.8%). 136 patients (22.6%) died in hospital, and 26 (4.3%) during the 90-day follow-up. Conclusions We observed that levosimendan was used in accordance with recent recommendations by French physicians. Hypotension and atrial fibrillation remained the most frequent side-effects, while serious adverse event potentially attributable to levosimendan were infrequent. The results suggest that this medication was safe and potentially associated with some benefit in the population studied

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Utilisation de la métabolomique par RMN du proton pour l'évaluation de la variabilité préanalytique d'échantillons biologiques

La recherche de biomarqueurs est devenue un enjeu crucial dans le domaine de la santé notamment afin de permettre un diagnostic précoce, une indication pronostique ou une orientation thérapeutique. Les méthodes et techniques de recherche devenant de plus en plus pointues, notamment les techniques OMICs, un grand nombre d échantillons est nécessaire pour le bon déroulement des études. En effet, il est important de pouvoir travailler sur un grand nombre de patients par groupe pour augmenter la spécificité des panels de biomarqueurs mis en évidence, ainsi que leur pouvoir discriminant. Afin de répondre à cette demande, l utilisation d échantillons provenant de diverses sources est nécessaire, d où l exposition à une variabilité préanalytique des échantillons. C est dans ce contexte que s inscrit cette étude qui a pour but d observer l influence des conditions préanalytiques sur des échantillons biologiques et notamment sur des échantillons sanguins. L approche utilisée est la métabolomique par RMN 1H. Une méthode statistique a été utilisée afin de traiter les données, notamment une méthode de régression des moindres carrés partiels. Cette approche a permis d observer que l influence des conditions préanalytiques sur les échantillons sanguins est minime du moment que l échantillon reste à 4C, en revanche la conservation des échantillons à température ambiante modifie le profil métabolique de même que les cycles de congélation-décongélation. On note des différences notamment sur les concentrations en glucose, en lactate et en certains acides aminés.The research for biomarkers has become a critical issue in the health field, in particular to enable early diagnosis, a prognostic indication or therapeutic orientation. Methods and technical researches are becoming increasingly sophisticated, especially with the -OMICS technics. A large number of samples is necessary for the proper conduct of the studies, mostly because it is important to be able to work on many patients in order to increase the specificity of the identified biomarkers panels. To meet this demand, the use of samples from various sources is necessary. This is the reason why we expose the samples to a pre-analytical variability. In this context, the study Préanalytique s aim is to observe the influence preanalytical conditions have on biological samples, including blood samples. We used the approach by 1 H NMR metabolomics. A statistical method was subsequently used to process data, including a regression approach to partial least squares. This approach allowed us to observe that the influence of preanalytical conditions on blood samples is minimal, as long as the sample remains at 4 C. However the storage of samples at a room temperature changes the metabolic profile as well as the cycles of freeze-thaw. There are differences, including small but significant concentrations of glucose, lactate and some amino acids.AMIENS-BU Santé (800212102) / SudocSudocFranceF

Intérêt du bloc paravertebral continu pour l'analgésie pour l'analgésie post-opératoire en chirurgie renale et surrenalienne par laparotomie chez l'adulte

Contexte et objectif : La chirurgie abdominale par laparotomie génére des douleurs importantes et des consommations morphiniques parfois majeures. L'analgésie péridurale continue est la technique de référence en post opératoire de chirurgie thoracique ou abdominale, mais elle n'est pas dénuée de risques et d'effets secondaires qui imposent une surveillance spécialisée. Une alternative à l'analgésie péridurale esrt le bloc paravértébral. Le but de cette étude est d'évaluer l'intérêt du bloc paravértébral continu, e ncomplément d'analgésie, dans la prise en charge de la chirurgie rénale par laparotomie chez l'adulte, en terme d'épargne morphinique. Matériels et méthode : Les patients étaient randomisés en deux groupes et, après une ansthésie générale standardisé, ils recevaient pendant 48 heures : soit une perfusion continue de ropivacaine 0.2%, à travers un cathèter paravertébral (groupe BPV), soit une perfusion de sérum physiologique, à travers un cathèter sous-cutané (groupe PHY). De plus, il bénéficiaient d'une PCA morphine. Résultats : il s'agissait d'une opération intermédiaire, présentant les résultats issus de l'analyse de données des 30 premiers patients inclus et randomisés dans l'étude. L'étude met en évidence une réduction de la consommation morphinique dans les 24 premiéres heures post-opératoires dans le groupe BPV par au groupe PHY (9mg versus 39.5mg) ansi qu'une diminution des scores d'EVA à la mobilisation à H24 (5 versus 8 respectivement). Conclusion : Le bloc paravertébral continu assure une épargne morphinique et une réduction de la douleur à la mobilisation dans les 24 prenmières heures post-opératoires de chirurgie rénale par laparotomie.BREST-BU Médecine-Odontologie (290192102) / SudocSudocFranceF