International audienceUsing a call-by-value functional language as an example, this article illustrates the use of coinductive definitions and proofs in big-step operational semantics, enabling it to describe diverging evaluations in addition to terminating evaluations. We formalize the connections between the coinductive big-step semantics and the standard small-step semantics, proving that both semantics are equivalent. We then study the use of coinductive big-step semantics in proofs of type soundness and proofs of semantic preservation for compilers. A methodological originality of this paper is that all results have been proved using the Coq proof assistant. We explain the proof-theoretic presentation of coinductive definitions and proofs offered by Coq, and show that it facilitates the discovery and the presentation of the results

International audienceToday on-line services are the cornerstone of onlineapplications such as e-commerce, e-government and e-healthapplications. However, they raise several challenges about dataprivacy. Accountability, which is the property of an entity of beingresponsible for its acts, meets some of these challenges and henceincreases user’s trustworthiness in on-line applications. In thiswork, we propose an approach to assist the design of accountableapplications. In particular, we consider an application’s abstractcomponent design and we introduce a logical approach allowingvarious static verifications. This approach offers effective meansto early check the design and the behavior of an applicationand its offered/required services. We motivate our work with arealistic use case coming from the A4Cloud project and validateour proposal with experiments using a theorem prove

International audienceThe importance of the services-based market, 62.9% of the World gross domestic product (GDP), triggered an increase in the use of software offered on-line as services (SaaS). The use of such software usually implies the flow of personal data on-line between several parties. This can make users reluctant to their use. In this work, we consider this issue at the design-time of the software and we propose some foundations for an accountable software design. Accountability for a software is a property describing, among other aspects, its liability to end-users for the usage of the data it has been entrusted. We propose to enrich software's component design by accountability obligations using an abstract accountability language (AAL). We also define conditions for the well-formedness of an accountable component design and show how they can be checked using a model-checking tool

Abstract. In this paper we present an end-to-end solution to define and execute reliable dynamic reconfigurations of open component-based systems while guaranteeing their continuity of service. It uses a multistage approach in order to deal with the different kinds of possible errors in the most appropriate way; in particular, the goal is to detect errors as early as possible to minimize their impact on the target system. Reconfigurations are expressed in a restricted, domain-specific language in order to allow different levels of static and dynamic validation, thus detecting errors before executing the reconfiguration where possible. For errors that can not be detected early (including software and hardware faults), a runtime environment provides transactional semantics to the reconfigurations.

Neogene sediments from three areas of the Northern Indian Ocean (Indus Fan, Owen Ridge, Oman Margin, ODP Leg 117) were studied in order to determine the amount, type, and preservation of organic matter as functions of the environments encountered. The work consisted of geochemical analyses on whole sediment (Total Organic Content and Rock Eval pyrolysis) and of petrographic studies on isolated organic matter by optical and scanning electron microscopy. In Indus Fan sediments, organic matter is present in low amounts, mainly as lignaceous fragments. A contrasting situation exists in Oman Margin sediments which are generally rich in amorphous autochtonous organic matter. Owen Ridge, located between Indus fan and Oman Margin areas, shows two phases of organic sedimentation as a consequence of the uplift of the ridge. The older phase (Oligocene to early or middle Miocene) is strongly influenced by detrital supply from the Indus, while the younger phase (middle Miocene to Pleistocene) is characterized by relatively high amounts of autochtonous organic matter. From a general point of view it appears that high amounts of organic matter are mainly due to good preservation of marine amorphous organic matter, such as in Oman Margin sediments and in upper pelagic levels of Indus Fan and Owen Ridge deposits. Low total organic carbon contents are correlated with low proportions of amorphous material in the total organic matter due to oxidizing conditions. This leads to a relative enrichment in components derived from resistant materials (lignin, chitin, or other resistant biopolymers) such as lignaceous fragments (Indus Fan) and/or fragments from benthic organisms and alveolate microplankton (Oman Margin).