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Réduction des besoins de confiance matérielle pour le développement d'un hyperviseur certifié
No full textThis thesis presents the design of a secured, software based hypervisor for certification purposes. The highest levels of certification require formal methods, which demonstrate the correctness of a product with regard to its specification using mathematical logic. Proven hardware is not available off-the-shelf. In order to reduce the Trusted Computing Base (TCB) and hence, the amount of specification and proofs to produce, virtualization mechanism are software-made. In addition, this enables virtualization on platforms which do not have virtualization-enabled hardware. The challenge for achieving this goal is twofold. On one hand, despite an existing documentation, the instruction set to be analysed has tedious corner cases, implementation-dependant behaviour or even worse, undefined behaviour. On the other hand to infer the system behaviors has to be infered given a discrete instruction flow, in order to remain interposed between the guest and the underlying hardware. For achieving this, the guest's machine code is analysed, and sensitive instructions (which threaten confidentiality or integrity) are replaced by traps, which enable arbitration given the actual guest context. Relying on hypothetically proven processor and memory management unit, only privileged code may bypass the configuration setup by the hypervisor and access the hardware. Thus, analysing unprivileged code is worthless in this case. Micro-kernel design which tends to offload most of the code in userspace, are suitable here. Using that paradigm reduces the overhead induced by certified virtualization.Cette thèse a pour objet la conception d'un hyperviseur logiciel sécurisé, à vocation de certification. Les plus hauts niveaux de certification requièrent l'usage de méthodes formelles, permettant de démontrer la validité d'un produit par rapport à une spécification à l'aide de la logique mathématique. Le matériel prouvé n'existant pas, les mécanismes d'hypervision sont implémentés en logiciel. Cela contribue à réduire la base de confiance, et donc la quantité de modélisation et de preuve à produire. En outre, cela rend possible la virtualisation de systèmes sur des plateformes qui ne sont pas dotées d'instructions de virtualisation. Les principaux challenges sont l'analyse du jeu d'instruction qui, malgré l'existence de documentation, comporte des ambiguïtés, des particularités dépendantes de l'implémentation et des comportements non définis. Puis, l'identification des intensions d'un système invité étant donné un flot d'instructions discret afin de rester en interposition avec le matériel sous-jacent. Pour ce faire, le code machine de l'invité est analysé et les instructions menaçant l'intégrité ou la confidentialité du système sont remplacées par des trapes logicielles, provoquant une analyse du contexte afin d'autoriser ou non leur exécution. Reposant sur l'existence d'un CPU et d'une MMU prouvés, seul du code privilégié est susceptible d'outrepasser les droits d'accès configurés par l'hyperviseur. Il n'est donc pas nécessaire d'hyperviser le code non privilégié. Les micro-noyau, généralement choisis pour leur légèreté, ont donc un second avantage : ils réduisent au minimum le surcoût de l’hypervision
Consensus tracking of fractional-order multi-agent systems based on sliding mode estimator
No full textInternational audienc
Multi-Hop Ridematching optimization problem: Intelligent chromosome agent-driven approach
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Agents endowed with uncertainty management behaviors to solve a multiskill healthcare task scheduling
No full textInternational audienceHealth organizations are complex to manage due to their dynamic processes and distributed hospital organization. It is therefore necessary for healthcare institutions to focus on this issue to deal with patients' requirements. We aim in this paper to develop and implement a management decision support system (DSS) that can help physicians to better manage their organization and anticipate the feature of overcrowding. Our objective is to optimize the Pediatric Emergency Department (PED) functioning characterized by stochastic arrivals of patients leading to its services overload. Human resources allocation presents additional complexity related to their different levels of skills and uncertain availability dates. So, we propose a new approach for multi-healthcare task scheduling based on a dynamic multi-agent system. Decisions about assignment and scheduling are the result of a cooperation and negotiation between agents with different behaviors. We therefore define the actors involved in the agents' coalition to manage uncertainties related to the scheduling problem and we detail their behaviors. Agents have the same goal, which is to enhance care quality and minimize long waiting times while respecting degrees of emergency. Different visits to the PED services and regular meetings with the medical staff allowed us to model the PED architecture and identify the characteristics and different roles of the healthcare providers and the diverse aspects of the PED activities. Our approach is integrated in a DSS for the management of the Regional University Hospital Center (RUHC) of Lille (France). Our survey is included in the French National Research Agency (ANR) project HOST (Hôpital: Optimisation, Simulation et évitement des Tensions (ANR-11-TecSan-010: http://host.ec-lille.fr/wp-content/themes/twentyeleven/docsANR/R0/ HOST-WP0.pdf))
GENESIS: a French national resource to study the missing heritability of breast cancer
No full textInternational audienceBackground: Less than 20 % of familial breast cancer patients who undergo genetic testing for BRCA1 and BRCA2 carry a pathogenic mutation in one of these two genes. The GENESIS (GENE SISter) study was designed to identify new breast cancer susceptibility genes in women attending cancer genetics clinics and with no BRCA1/2 mutation. Methods: The study involved the French national network of family cancer clinics. It was based on enrichment in genetic factors of the recruited population through case selection relying on familial criteria, but also on the consideration of environmental factors and endophenotypes like mammary density or tumor characteristics to assess potential genetic heterogeneity. One of the initial aims of GENESIS was to recruit affected sibpairs. Siblings were eligible when index cases and at least one affected sister were diagnosed with infiltrating mammary or ductal adenocarcinoma, with no BRCA1/2 mutation. In addition, unrelated controls and unaffected sisters were recruited. The enrolment of patients, their relatives and their controls, the collection of the clinical, epidemiological, familial and biological data were centralized by a coordinating center
The relationship between profit-sharing schemes and wages: Evidence from French firms
No full textInternational audienceThe article tackles the impact of profit sharing plans (PS) on compensation policies in the French context. Using a sample of 1,143 firms from surveys of the Ministry of Labour, the authors draw up a typology based on a mix of PS plans including cashbased PS, deferred PS and the intensity of deferred plans (additional employer and employee contributions). Our results indicate that profit sharing does not seem to be considered as a way to reduce wages. Cash-based PS-oriented and high-deferred PS policies are not significantly linked to lower wages; but only firms with high-deferred PS policies are related to significantly higher wages
Distributed Consensus-Based Robust Adaptive Formation Control for Nonholonomic Mobile Robots with Partial Known Dynamics
No full textInfluence of a screening navigation program on social inequalities in health beliefs about colorectal cancer screening
No full textInternational audienceThe aim of the study was to test whether a screening navigation program leads to more favorable health beliefs and decreases social inequalities in them. The selected 261 noncompliant participants in a screening navigation versus a usual screening program arm had to respond to health belief measures inspired by the Protection Motivation Theory. Regression analyses showed that social inequalities in perceived efficacy of screening, favorable attitude, and perceived facility were reduced in the screening navigation compared to the usual screening program. These results highlight the importance of health beliefs to understand the mechanism of screening navigation programs in reducing social inequalities
Biotransformation of organic matter during composting of solid wastes from traditional tanneries by thermochemolysis coupled with gas chromatography and mass spectrometry
No full textInternational audienceIn the present paper, Thermochemolysis (or Thermally Assisted Hydrolysis/Methylation) is used as a way of following the biotransformation of organic matter during composting of solid wastes from traditional tanneries. The qualitative analysis of the pyrograms allowed us to discriminate between four main families of compounds: aromatic compounds, lipids, polysaccharides and nitrogen-containing substances. The quantitative data revealed some variations in the chemical composition of the macromolecular content. Lipids are the most transformed fraction during the composting process. Animal and plant fatty acids showed a sensible decrease. Fungal fatty acids mainly increased during the thermophilic phase whereas bacterial fatty acids increased when the growth of fungi is repressed. During composting of solid wastes from traditional tanneries an adapted microbial community has been developed. Various lignin-derived units during composting showed a strong increase in p-hydroxyphenyl type-compounds in comparison with the other aromatic structures due to high decomposition of grass cuttings. Tannin derived compounds also increased throughout the composting. Lignin and condensed tannins polymers are partially degraded and stabilized by covalent linkage to more complex organic molecules such as humic substances. Nitrogen containing compounds increased during composting as a consequence of the high rate of degradation of the other fractions and/or their combination with polyphenolic structure leading to the formation of humic substances. In our study a correlation was found between NTK and nitrogen containing substances
