Formal verification of Mobile Robot Protocols

Mobile robot networks emerged in the past few years as a promising distributed computing model. Existing work in the literature typically ensures the correctness of mobile robot protocols via \emph{ad hoc} handwritten proofs, which, in the case of asynchronous execution models, are both cumbersome and error-prone. In this paper, we propose the first formal model and general verification (by model-checking) methodology for mobile robot protocols operating in a discrete space (that is, the set of possible robot positions is finite). Our contribution is threefold. First, we formally model using synchronized automata a network of mobile robots operating under various synchrony (or asynchrony) assumptions. Then, we use this formal model as input model for the DiVinE model-checker and prove the equivalence of the two models. Third, we verify using DiVinE two known protocols for variants of the ring exploration in an asynchronous setting (exploration with stop and perpetual exclusive exploration). The exploration with stop we verify was manually proved correct only when the number of robots is $k>17$, and $n$ (the ring size) and $k$ are co-prime. As the necessity of this bound was not proved in the original paper, our methodology demonstrates that for several instances of $k$ and $n$ \emph{not covered} in the original paper, the algorithm remains correct. In the case of the perpetual exclusive exploration protocol, our methodology exhibits a counter-example in the completely asynchronous setting where safety is violated, which is used to correct the original protocol

Les ratés de cuisson du haut Moyen Âge de l’atelier de Saran

Actuellement considérée comme accueillant la plus importante agglomération potière du haut Moyen Âge jamais explorée, la commune de Saran (Loiret) a livré depuis bientôt 50 ans une quantité impressionnante de rebuts de cuissons. Au gré des recherches, leur examen attentif, couplé à celui des autres vestiges laissés par cet artisanat, a progressivement alimenté une histoire complexe de la chaîne opératoire potière, depuis la matière première jusqu’au produit fini. Les réponses apportées aux questionnements sur les traces discrètes visibles sur ces centaines de milliers de fragments de vases ratés éclairent d’un jour nouveau les gestes du potier, l’équipement de l’atelier, les moyens de production et plus globalement les savoir-faire.Currently considered to host the largest pottery settlement of the Middle Ages ever explored, the town of Saran (Loiret) has delivered for nearly 50 years an impressive amount of firing scraps. In the course of research, their careful examination, coupled with that of the other vestiges left by this craft, has progressively supplied a complex history of the potter's operational chain, from the raw material to the finished product. The answers given to the questions about the discrete traces visible on these hundreds of thousands of fragments of failed vases shed new light on the potter's gestures, the equipment of the workshop, the means of production and, more generally, the know how.Desde hace casi 50 años, la comuna de Saran –situada en el departamento de Loiret– ha aportado una cantidad impresionante de desechos de cocción, siendo considerada actualmente la mayor aglomeración alfarera de la Alta Edad Media explorada hasta ahora. El análisis detallado al filo de las investigaciones, asociado al de los demás vestigios dejados por este artesanado, ha ido alimentando progresivamente una historia compleja de la cadena operatoria alfarera, desde la primera materia prima hasta el producto final. Las respuestas a los cuestionamientos relativos a las huellas –discretas pero visibles– en miles de fragmentos de jarros desechados han aportado nuevas luces sobre los gestos del alfarero, el equipamiento del taller, los medios de producción y, de forma más amplia, sobre el saber hacer alfarero

Quinine-Resistant Malaria in Traveler Returning from Senegal, 2007

We describe clinical and parasitologic features of in vivo and in vitro Plasmodium falciparum resistance to quinine in a nonimmune traveler who returned to France from Senegal in 2007 with severe imported malaria. Clinical quinine failure was associated with a 50% inhibitory concentration of 829 nmol/L. Increased vigilance is required during treatment follow-up

Control Architecture Concepts and Properties of an Ontology Devoted to Exchanges in Mobile Robotics

National audienceA specific ontology is proposed in the scope of the development of a platform devoted to exchanges between academics and industrials of the robotic domain. This paper presents the tools used for knowledge elicitation, the concepts and properties linked with control architecture, the use of the resulting ontology for description of some scenarios and the tracks for the development of a domain specific language grounded on the ontology. Knowledge elicitation is performed in web ontology language thanks to Protégé ontology editor. The ontology is structured as a set of modules organized around a kernel. Modules addressing systems, information, robot and mission include concepts and properties for control architecture description. The expressivity of the ontology is demonstrated describing architectures for a set of scenarios; urban robotic scenario, air-ground scenario, landmark search scenario and military unmanned aerial vehicles scenario. Finally some tracks for the use of the ontology for developing a domain specific language are given

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon

The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe

Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks

A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at root s = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb(-1). The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t (t) over bar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 confidence level for the product of the production cross section and branching fraction sigma(gg -> X) B(X -> HH -> b (b) over barb (b) over bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with amass scale Lambda(R) = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV

Measurement of the top quark mass using charged particles in pp collisions at root s=8 TeV

Peer reviewe