A Fixpoint Semantics of Event Systems with and without Fairness Assumptions

We present a fixpoint semantics of event systems. The semantics is presented in a general framework without concerns of fairness. Soundness and completeness of rules for deriving "leads-to" properties are proved in this general framework. The general framework is instantiated to minimal progress and weak fairness assumptions and similar results are obtained. We show the power of these results by deriving sufficient conditions for "leads-to" under minimal progress proving soundness of proof obligations without reasoning over state-traces

Diseño y construcción de programas mediante CSP

En este artículo presentamos, a través de un caso de estudio, el desarrollo de programas paralelos mediante métodos formales. El caso de estudio es el núcleo básico de un sistema operativo multitarea, y el método formal utilizado es la teoría de procesos secuenciales comunicantes, CSP. CSP es una teoría de programación que permite modelar sistemas mediante procesos comunicantes. Los procesos se modelan mediante un conjunto de eventos observables del sistema a implantar. CSP dispone de un lenguaje de especificación que permite describir el comportamiento de los procesos a través de sus eventos observables. La especificación inicial de un sistema debe ser lo suficientemente abstracta para indicar lo que el sistema debe hacer, sin dar detalles de cómo lo hace. Para dar tales detalles, una especificación debe refinarse de manera paulatina; esto se hace a través de pasos de refinamiento. En cada paso de refinamiento se debe probar que el refinamiento satisface los criterios de la especificación original; para dar tal garantía, CSP dispone de un conjunto de leyes algebraicas. El diseño y construcción del núcleo básico de un sistema operativo inicia con la especificación del entrelazamiento de acciones que modela nuestra intuición del paralelismo de un monitor multitareas. Esta especificación es refinada para itroducir los mecanismos necesarios para implantar la conmutación entre tareas del monitor. Se da la prueba formal de ciertos refinamientos y en otros, donde la complejidad aumenta, utilizamos FDR, un sistema que de manera automática, verifica la corrección de los refinamientos.Eje: Ingeniería de software. Bases de datosRed de Universidades con Carreras en Informática (RedUNCI

Fatty acids homeostasis during fasting predicts protection from chemotherapy toxicity.

Fasting exerts beneficial effects in mice and humans, including protection from chemotherapy toxicity. To explore the involved mechanisms, we collect blood from humans and mice before and after 36 or 24 hours of fasting, respectively, and measure lipid composition of erythrocyte membranes, circulating micro RNAs (miRNAs), and RNA expression at peripheral blood mononuclear cells (PBMCs). Fasting coordinately affects the proportion of polyunsaturated versus saturated and monounsaturated fatty acids at the erythrocyte membrane; and reduces the expression of insulin signaling-related genes in PBMCs. When fasted for 24 hours before and 24 hours after administration of oxaliplatin or doxorubicin, mice show a strong protection from toxicity in several tissues. Erythrocyte membrane lipids and PBMC gene expression define two separate groups of individuals that accurately predict a differential protection from chemotherapy toxicity, with important clinical implications. Our results reveal a mechanism of fasting associated with lipid homeostasis, and provide biomarkers of fasting to predict fasting-mediated protection from chemotherapy toxicity.General: We thank Prof. Jose Maria. Ordovas for his kind suggestions; nutritionists Helena Marcos-Pasero, Elena Aguilar-Aguilar and Isabel Espinosa-Salinas for their help with volunteers management; Rosa Serrano for her help with animal experiments; Susana Molina for her advice with PBMC isolation; Luisa Mariscal, Domingo Fernandez, Lola Martinez, Diego Megias, Patricia Gonzalez, Fernando Pelaez, Anabel Sanz, Carolina Pola, Celia de la Calle, Ana Ortega, Ana Sagrera, Jose Miguel Frade, Elena Lopez-Guadamillas, Maribel Munoz, Susana Llanos, Andres Fernandez, Aranzazu Sierra, Andres Lopez, Noemi Haro and Ildefonso Rodriguez for their excellent technical and scientific support. Work at the laboratory of P.J.F.M. is funded by the Ramon Areces Foundation, (CIVP18A3891), Asociacion Espanola contra el Cancer-AECC (SIRTBIO-LABAE18008FERN), a Ramon y Cajal Award from the Spanish Ministry of Science, Innovation and Universities (MICINN) (RYC-2017-22335), RETOS projects Program of MICINN (SAF2017-85766-R) and the Portuguese Foundation for Science and Technology (FCT-MCTES, SFRH/BD/124022/2016). Work at the laboratory of ARM was funded by the MICINN (PID2019-110183RB-C21), Regional Government of Community of Madrid (P2018/BAA-4343-ALIBIRD2020-CM) and the Ramon Areces Foundation. Work at the laboratory of A.D.R. Funded by the Comunidad de Madrid-Talento Grant 2018-T1/BMD-11966 and the MICINN PID-2019-106893RA-100. Work at the laboratory of L.D. is funded by projects from the Health Research Fund (ISCIII FIS PI14/01374 and FISPI17/00508) and from a Manuel de Oya research fellowship from the Beer and Health Foundation. Work at the laboratory of A.E. is funded by a Ramon y Cajal Award from MICINN (RYC-2013-13546) and RETOS projects Program of the MICINN, co-funded by the European Regional Development Fund (ERDF) (SAF2015-67538-R). Work in the laboratory of M.S. was funded by the IRB and by grants from the Spanish Ministry of Economy co-funded by the European Regional Development Fund (ERDF) (SAF2013-48256-R), the European Research Council (ERC-2014-AdG/669622), and the "laCaixa" Foundation.S

Propriétés de vivacité sous conditions d'équité et<br />sémantique des systèmes d'événements avec la méthode B

ABSTRACTThis thesis proposes an approach to the specification and proof of liveness propertiesunder fairness assumptions in B event system and presents a semantics for these propertiesfounded on fixpoints of set transformers. The proposal uses a unity-like logic to specify andverify liveness properties under minimal progress and weak fairness assumptions and presentsrules to preserve these properties under refinement. The fixpoint semantics allows us to makethe notion of reachability under fairness assumptions equivalent to the one of terminationof iteration of events. Soundness and completeness of rules to derive liveness properties areproved, thanks to this equivalence. Moreover, the fixpoint semantics provides the foundationsto prove soundness of both the rules for verification of liveness properties and the rules forthe preservation of liveness under refinement.Cette thèse propose une approche à la spécification et preuve des propriétés de vivacitéavec hypothèses d'équité en B événementiel et présente une sémantique pour ces propriétésfondée sur de points fixes de transformateurs d'ensembles. La proposition utilise une logiquede programmation issue de la logique unity pour spécifier et vérifier des propriétés de vivacitésous des hypothèses de progrès minimal et d'équité faible et présente des règles pour préserverces propriétés dans les raffinements. La sémantique de points fixes nous permet de faireéquivalentes les notions d'atteignabilité sous les hypothèses d'équité et de terminaison del'itération d'événements. Cela nous permet de prouver la correction et la complétude desrègles permettant la dérivation des propriétés de vivacité. En outre, cela donne les fondementspour prouver la correction des règles permettant la vérification des propriétés de vivacité etdes règles permettant la préservation de la vivacité sous raffinement

Proof obligations for specification and refinement of liveness properties under weak fairness

In this report, we present a formel model of fair iteration of events for B event systems. The model is used to justify proof obligations for basic liveness properties and preservation under refinement of general liveness properties. The model of fair iteration of events uses the dovetail operator, an operator proposed by Broy and Nelson to model fair choice. The proofs are mainly founded in fixpoint calculations of fair iteration of events and weakest precondition calculus

Programmation d'un noyau UNIX en GAMMA

Disponible dans les fichiers attachés à ce documen

A formal requirements modeling approach: application to rail communication

International audienceThis paper is about the formal specification of requirements of a rail communication protocol called Saturn, proposed by ClearSy systems engineering, a French company specialised in safety critical systems. The protocol was developed and implemented within a rail product, widely used, without modeling, verifying and even documenting its requirements. This paper outlines the formal specification, verification and validation of Saturn’s requirements in order to guarantee its correct behavior and to allow the definition of slightly different product lines. The specification is performed according to SysML/KAOS, a formal requirements engineering method developed in the ANR FORMOSE project for critical and complex systems. System requirements, captured with a goal modeling language, give rise to the behavioral part of a B System specification. In addition, an ontology modeling language allows the specification of domain entities and properties. The domain models thus obtained are used to d erive the structural part of the B System specification obtained from system requirements. The B System model, once completed with the body of events, can then be verified and validated using the whole range of tools that support the B method. Five refinement levels of the rail communication protocol were constructed. The method has proven useful. However, several missing features were identified. This paper also provides a formally defined extension of the modeling languages to fill the shortcomings

Programmation d'un noyau UNIX en GAMMA

Programme 3 : intelligence artificielle, systemes cognitifs et interaction homme-machineSIGLEAvailable at INIST (FR), Document Supply Service, under shelf-number : 14802 E, issue : a.1991 n.1489 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc