Reachability Analysis of Innermost Rewriting

We consider the problem of inferring a grammar describing the output of a functional program given a grammar describing its input. Solutions to this problem are helpful for detecting bugs or proving safety properties of functional programs and, several rewriting tools exist for solving this problem. However, known grammar inference techniques are not able to take evaluation strategies of the program into account. This yields very imprecise results when the evaluation strategy matters. In this work, we adapt the Tree Automata Completion algorithm to approximate accurately the set of terms reachable by rewriting under the innermost strategy. We prove that the proposed technique is sound and precise w.r.t. innermost rewriting. The proposed algorithm has been implemented in the Timbuk reachability tool. Experiments show that it noticeably improves the accuracy of static analysis for functional programs using the call-by-value evaluation strategy

La difficile question des biens publics en agriculture : réflexions autour des outils économiques

[Paper in French] The European Union (EU) has gradually increased the importance of environmental issues in the objectives and instruments of the Common Agricultural Policy (CAP). Agro-environmental schemes, enforced within all of the Member States since the 90’s, are contracted by the farmers on a voluntary basis. Since the enforcement, in 2005, of the cross-compliance of the whole CAP direct payment, almost all farms in the EU are now subject to environmental and sanitary constraints. The efficiency of these mechanisms and their consistency with pre-existing instruments are nonetheless questionable, as shown by various research and evaluation reports. However, the provision of public goods through agriculture can be seen as a legitimate objective of the agricultural policy, even though the clear wish to propose a simplified CAP does not prima facie fit with a broad consideration of the public good issue in agriculture. This article proposes a critical review of the CAP in reference to that objective. A particular attention is paid to the provision of environmental public goods based on the assessment of past actions and recent progress. Besides, we question whether the CAP should, and could, support the farmers in meeting objectives in terms of environmental production. Our analysis intends to shed light on these issues which are currently largely debated. Finally, we present perspectives offered by economic instruments that could be mobilised in view of delineating the different options for the future CAP (post-2013). Within the next years technological progress, market forces, and the impacts of climate change will probably be the most important drivers of the evolution of agricultural structures, and therefore of the provision of environmental public goods. With its influence on the various determinants of the agricultural activities, the CAP has a key-role to play in the provision of such public goods. Hence, the future policy will have to pay greater attention to public goods if, in response to the social demand, it is decided to make them one of the backbones of the new CAP design. However, such a greening reorientation of the policy can turn thorny with respect to the maintenance of the initial objectives of the European policy: securing farms’ viability and maintaining the competitiveness of the agricultural sector within the EU.Common Agricultural Policy, public goods, agriculture, environment, economic instruments

Stochastic Inference of Surface-Induced Effects using Brownian Motion

Brownian motion in confinement and at interfaces is a canonical situation, encountered from fundamental biophysics to nanoscale engineering. Using the Lorenz-Mie framework, we optically record the thermally-induced tridimensional trajectories of individual microparticles, within salty aqueous solutions, in the vicinity of a rigid wall, and in the presence of surface charges. We construct the time-dependent position and displacement probability density functions, and study the non-Gaussian character of the latter which is a direct signature of the hindered mobility near the wall. Based on these distributions, we implement a novel, robust and self-calibrated multifitting method, allowing for the thermal-noise-limited inference of diffusion coefficients spatially-resolved at the nanoscale, equilibrium potentials, and forces at the femtoNewton resolution

Competition-based Model of Pruning: Applications to Apple Trees

International audienceno abstrac

Clathration of Volatiles in the Solar Nebula and Implications for the Origin of Titan's atmosphere

We describe a scenario of Titan's formation matching the constraints imposed by its current atmospheric composition. Assuming that the abundances of all elements, including oxygen, are solar in the outer nebula, we show that the icy planetesimals were agglomerated in the feeding zone of Saturn from a mixture of clathrates with multiple guest species, so-called stochiometric hydrates such as ammonia hydrate, and pure condensates. We also use a statistical thermodynamic approach to constrain the composition of multiple guest clathrates formed in the solar nebula. We then infer that krypton and xenon, that are expected to condense in the 20-30 K temperature range in the solar nebula, are trapped in clathrates at higher temperatures than 50 K. Once formed, these ices either were accreted by Saturn or remained embedded in its surrounding subnebula until they found their way into the regular satellites growing around Saturn. In order to explain the carbon monoxide and primordial argon deficiencies of Titan's atmosphere, we suggest that the satellite was formed from icy planetesimals initially produced in the solar nebula and that were partially devolatilized at a temperature not exceeding 50 K during their migration within Saturn's subnebula. The observed deficiencies of Titan's atmosphere in krypton and xenon could result from other processes that may have occurred both prior or after the completion of Titan. Thus, krypton and xenon may have been sequestrated in the form of XH3+ complexes in the solar nebula gas phase, causing the formation of noble gas-poor planetesimals ultimately accreted by Titan. Alternatively, krypton and xenon may have also been trapped efficiently in clathrates located on the satellite's surface or in its atmospheric haze.Comment: Accepted for publication in The Astrophysical Journa

La Roche-Blanche – Gergovie (fortifications)

Identifiant de l'opération archéologique : 2005/136 et 2007/110 Date de l'opération : 2007 (FP) Le site de Gergovie est connu pour avoir livré, sur l’ensemble du plateau basaltique sur lequel il est implanté, les vestiges d’une occupation dense et étendue du Ier  s. av. J.-C. et du début de la période romaine. Toutefois, notre perception de la ville antique repose essentiellement sur les résultats de recherches anciennes (travaux conduits entre le XVIIIe  s. et le milieu du XXe  s.), souve..

Disaster Operations Management: an Empirical Study from Thailand

Disasters have unpredictable and deleterious impacts on modern societies. While recent operations management research has increasingly focused on disaster operations, only a few studies have examined the recovery phase of post-disaster operations. This research presents an overview of Disaster Operations Management as well as an empirical study using econometrics analysis to examine the recovery phase of post-disaster operations. The results suggest that when resources are scarce, at a strategic level we need to understand where to begin when planning the recovery process. This study is an exploratory analysis of the question of how flooding affects per capita income in areas with different levels of industrialization. We developed multiple regression models using panel data from Thailand to examine this effect, finding that flooding in a previous year has a positive effect on areas with a low level of industrialization, but a negative one on highly industrialized areas, meaning the residents of the latter are affected differently. Our results suggest the level of industrialization impacts the effectiveness of the recovery process. Finally, we discuss the implications of the study as well as suggestions for future research

Assessing the risk of importing dengue and chikungunya viruses to the European Union

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