Simple Isolation for an Actor Abstract Machine

Part 5: Efficient Verification TechniquesInternational audienceThe actor model is an old but compelling concurrent programming model in this age of multicore architectures and distributed services. In this paper we study an as yet unexplored region of the actor design space in the context of concurrent object-oriented programming. Specifically, we show that a purely run-time, annotation-free approach to actor state isolation with reference passing of arbitrary object graphs is perfectly viable. In addition, we show, via a formal proof using the Coq proof assistant, that our approach indeed enforces actor isolation

Mécanismes logiciels de protection mémoire

Le but de ce travail est de montrer qu'il est possible de fournir à un système d'exploitation des mécanismes permettant d'isoler des composants logiciels à grain fin. L'approche contraste avec les mécanismes matériels de protection mémoire des systèmes actuels permettant par l'intermédiaire de l'unité de gestion de la mémoire d'isoler les processus dans des espaces d'adressage virtuel différents. Notre approche repose sur l'utilisation d'un langage de programmation sûr pour segmenter un unique espace d'adresse virtuel en domaines d'isolation mémoire appelées des agents. Nos principales contributions sont un mécanisme efficace de communication (sans copie) entre les agents du système et un moteur d'exécution permettant à plusieurs milliers d'agents de . s'exécuter simultanément.This thesis aims at providing mechanisms suitable for fine-grain memory isolation. Our approach contrasts with mechanisms used by commodity operating systems to provide memory isolation trough the concept of processes, whereby real memory is virtualized into address spaces. Our approach is to rely on virtual machine technology that provides a safe instruction set to split a same virtual address space in isolation domains called agents. Our contribution is an efficient zero-copy communication mechanism and an execution engine that comfortably scales to handle thousands of agents on modest hardware.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Message Passing: A Case for Mixing Deep-Copy and Migration

Les rapports de recherche du LIG - ISSN: 2105-0422This paper proposes an ownership model that permits to combine both a deep-copy and migration semantics within one consistent message-oriented programming model for Java. We argue that both semantics are necessary to cover the complete spectrum of application patterns. We also argue that one memory isolation mechanism is enough to provide strict memory isolation (isolate style) and message-oriented isolation suited for concurrent programming (actor style). Our proposal combines strict memory isolation, modeled on Java isolates (JSR 121),and a message passing that can send unconstrained object graphs, either migrating or deep-copying them. To our knowledge, our ownership model is the only model that does not specialize classes for their use in messages and still enables fast migration of unconstrained object graphs. Our performances show that the technology is suitable for interpreted virtual machines and are strong evidence that it is also suited for high-performance virtual machine based on JIT compilation

Une approche architecturale pour l'auto-protection de système répartis

National audienceLa complexité des systèmes répartis d'aujourd'hui est telle que la présence de bogues et de failles de sécurité est statistiquement inévitable. Une approche très prometteuse pour répondre à ce problème est la construction d'un système auto protégé, qui fonctionnerait de façon analogue à un système immunitaire biologique, capable de détecter l'intrusion d'éléments suspects au sein du système et de réagir à une attaque en cours. Nous avons conçu et implémenté un système autonome appelé JADE qui repose sur une architecture à composants logiciels pour reconfigurer des applications en réaction à des évènements observés. La connaissance de l'architecture de l'application peut être utilisée pour détecter des activités étrangères et pour déclencher des contre-mesures. Nous décrivons comment cette approche peut être appliquée pour ajouter la capacité d'auto protection à une grappe d'application J2EE

From Autonomic to Self-Self Behaviors: The JADE Experience

International audienceAutonomic computing enables computing infrastructures to perform administration tasks with minimal human intervention. This wrap-up paper describes the experience we gained with the design and use of Jade---an architecture-based autonomic system. The contributions of this article are, (1) to explain how Jade provides autonomic management of a distributed system through an architecture-based approach, (2) to explain how we extended autonomic management from traditional self behaviors such as repairing or protecting a managed system to self-self behaviors where Jade also fully manages itself as it manages any other distributed system, (3) to report on our experience reaching self-self behaviors for two crucial autonomic properties, repair and protection

Self-Protected System: an experiment

The complexity of today's distributed computing environment is such that the presence of bugs and security holes is statistically unavoidable. A very promising approach to this issue is to implement a self-protected system, similarly to a natural immune system which has the ability to detect the intrusion of foreign elements within the system. We designed and implemented an autonomic system called Jade, which relies on software component architectures to reconfigure applications according to observed events. The knowledge of the application architecture can be used to detect foreign activities and to trigger counter-measures. We described how this approach can be applied the provide self-protection for a clustered J2EE application

Le développement. De la conception à l'adolescence

International audienceQuelles sont les étapes normales du développement ? Comment repérer le développement pathologique ? Comment y remédier ? Un panorama global et actuel du développement normal et pathologique. Reconnaître les visages, communiquer, lire, calculer, résoudre des problèmes... le développement accompagne chaque instant de nos vies. Quelles en sont les étapes normales ? Comment repérer le développement pathologique ? Comment y remédier ? Les connaissances concernant le développement de l'être humain ne cessent de croître depuis quelques années : évolutions techniques, mais également évolutions théoriques. Parallèlement, les transformations sociétales (familles monoparentales, allongement de l'espérance de vie, modification de l'environnement numérique) obligent à repenser la place de l'enfant et de l'adolescent. Et c'est en conséquence la place du psychologue dans la société qui est aussi à réimaginer. Cet ouvrage collectif donne la parole à des spécialistes du développement de l'être humain. Ouvertures théoriques, méthodologiques, cliniques offrent, en 12 fiches, un panorama global et actuel du développement normal et pathologique

Characterization of the plastidial geraniol synthase from Madagascar periwinkle which initiates the monoterpenoid branch of the alkaloid pathway in internal phloem associated parenchyma

Madagascar periwinkle (Catharanthus roseus [L.] G. Don, Apocynaceae) produces monoterpene indole alkaloids (MIAs), secondary metabolites of high interest due to their therapeutic value. A key step in the biosynthesis is the generation of geraniol from geranyl diphosphate (GPP) in the monoterpenoid branch of the MIA pathway. Here we report on the cloning and functional characterization of C. roseus geraniol synthase (CrGES). The full-length CrGES was over-expressed in Escherichia coli and the purified recombinant protein catalyzed the conversion of GPP into geraniol with a Km value of 58.5 μM for GPP. In vivo CrGES activity was evaluated by heterologous expression in a Saccharomyces cerevisiae strain mutated in the farnesyl diphosphate synthase gene. Analysis of culture extracts by gas chromatography-mass spectrometry confirmed the excretion of geraniol into the growth medium. Transient transformation of C. roseus cells with a Yellow Fluorescent Protein-fusion construct revealed that CrGES is localized in plastid stroma and stromules. In aerial plant organs, RNA in situ hybridization showed specific labeling of CrGES transcripts in the internal phloem associated parenchyma as observed for other characterized genes involved in the early steps of MIA biosynthesis. Finally, when cultures of Catharanthus cells were treated with the alkaloid-inducing hormone methyl jasmonate, an increase in CrGES transcript levels was observed. This observation coupled with the tissue-specific expression and the subcellular compartmentalization support the idea that CrGES initiates the monoterpenoid branch of the MIA biosynthetic pathway

Gene coexpression analysis reveals complex metabolism of the monoterpene alcohol linalool in Arabidopsis flowers.

The cytochrome P450 family encompasses the largest family of enzymes in plant metabolism, and the functions of many of its members in Arabidopsis thaliana are still unknown. Gene coexpression analysis pointed to two P450s that were coexpressed with two monoterpene synthases in flowers and were thus predicted to be involved in monoterpenoid metabolism. We show that all four selected genes, the two terpene synthases (TPS10 and TPS14) and the two cytochrome P450s (CYP71B31 and CYP76C3), are simultaneously expressed at anthesis, mainly in upper anther filaments and in petals. Upon transient expression in Nicotiana benthamiana, the TPS enzymes colocalize in vesicular structures associated with the plastid surface, whereas the P450 proteins were detected in the endoplasmic reticulum. Whether they were expressed in Saccharomyces cerevisiae or in N. benthamiana, the TPS enzymes formed two different enantiomers of linalool: (-)-(R)-linalool for TPS10 and (+)-(S)-linalool for TPS14. Both P450 enzymes metabolize the two linalool enantiomers to form different but overlapping sets of hydroxylated or epoxidized products. These oxygenated products are not emitted into the floral headspace, but accumulate in floral tissues as further converted or conjugated metabolites. This work reveals complex linalool metabolism in Arabidopsis flowers, the ecological role of which remains to be determined