Alternating Nonzero Automata

We introduce a new class of automata on infinite trees called alternating nonzero automata, which extends the class of non-deterministic nonzero automata. The emptiness problem for this class is still open, however we identify a subclass, namely limited choice, for which we reduce the emptiness problem for alternating nonzero automata to the same problem for non-deterministic ones, which implies decidability. We obtain, as corollaries, algorithms for the satisfiability of a probabilistic temporal logic extending both CTL* and the qualitative fragment of pCTL*

On Reversible Transducers

Deterministic two-way transducers define the robust class of regular functions which is, among other good properties, closed under composition. However, the best known algorithms for composing two-way transducers cause a double exponential blow-up in the size of the inputs. In this paper, we introduce a class of transducers for which the composition has polynomial complexity. It is the class of reversible transducers, for which the computation steps can be reversed deterministically. While in the one-way setting this class is not very expressive, we prove that any two-way transducer can be made reversible through a single exponential blow-up. As a consequence, we prove that the composition of two-way transducers can be done with a single exponential blow-up in the number of states. A uniformization of a relation is a function with the same domain and which is included in the original relation. Our main result actually states that we can uniformize any non-deterministic two-way transducer by a reversible transducer with a single exponential blow-up, improving the known result by de Souza which has a quadruple exponential complexity. As a side result, our construction also gives a quadratic transformation from copyless streaming string transducers to two-way transducers, improving the exponential previous bound

Taming denumerable Markov decision processes with decisiveness

Decisiveness has proven to be an elegant concept for denumerable Markov chains: it is general enough to encompass several natural classes of denumerable Markov chains, and is a sufficient condition for simple qualitative and approximate quantitative model checking algorithms to exist. In this paper, we explore how to extend the notion of decisiveness to Markov decision processes. Compared to Markov chains, the extra non-determinism can be resolved in an adversarial or cooperative way, yielding two natural notions of decisiveness. We then explore whether these notions yield model checking procedures concerning the infimum and supremum probabilities of reachability properties

Mixing Probabilistic and non-Probabilistic Objectives in Markov Decision Processes

In this paper, we consider algorithms to decide the existence of strategies in MDPs for Boolean combinations of objectives. These objectives are omega-regular properties that need to be enforced either surely, almost surely, existentially, or with non-zero probability. In this setting, relevant strategies are randomized infinite memory strategies: both infinite memory and randomization may be needed to play optimally. We provide algorithms to solve the general case of Boolean combinations and we also investigate relevant subcases. We further report on complexity bounds for these problems.Comment: Paper accepted to LICS 2020 - Full versio

Méthode de Monte Carlo et synthèse d'images : application à des milieux diffusants en transfert radiatif

International audienceL'objectif principal de cette étude est la prise en compte de la diffusion multiple pour le calcul de transferts radiatifs dans des géométries complexes. Pour traiter la diffusion, un algorithme basé sur la méthode de Monte Carlo a été développé et implémenté dans un environnement issu d'un code de synthèse d'images existant. A l'aide de propriétés d'invariance de la statistique des chemins de diffusion multiple, nous avons validé cette approche dans le cas de trois géométries tridimensionnelles usuelles : sphère, cylindre et pyramide

Model checking paramétrique statistique du plan de vol de drone civil

International audienceLes drones sont maintenant très répandus dans la société et sont souvent utilisés dans des situations dangereuses pour le public environnant. Il est alors nécessaire d'étudier leur fiabilité, en particulier dans le contexte de vols au-dessus d'un public. Dans cet article, nouś etudions la modélisation et l'analyse de drones dans le contexte de leur plan de vol. Pour cela, nous construisons un modèle probabiliste paramétrique du drone et l'utilisons ainsi que son plan de vol pour modéliser la trajectoire du drone. Ce modèle prend en compte des paramètres comme la défaillanceéventuelle du filtre ou du capteur (comme le GPS), ainsi que la force et la direction du vent. Du fait de la nature et de la complexité des modèles successifs obtenus, leur vérification avec les outils PRISM ou PARAM est impossible. Nous développons donc une nouvelle méthode d'approximation, appelée Parametric Statistical Model Checking, afin de calculer les probabilités de défaillance du drone. Cette méthode aété implémentée dans un prototype, que nous avons utilisé pour résoudre des difficultés complexes dans uneétude de cas réelle

Sensorimotor Difficulties Are Associated with the Severity of Autism Spectrum Conditions

Present diagnostic criteria for autism spectrum conditions (ASC) include social communication and interaction difficulties, repetitive behaviour and movement, and atypical sensory responsivity. Few studies have explored the influence of motor coordination and sensory responsivity on severity of ASC symptoms. In the current study, we explore whether sensory responsivity and motor coordination differences can account for the severity of autistic behaviours in children with ASC. 36 children took part: 18 (13 male, 5 female) with ASC (ages 7-16: mean age 9.93 years) and 18 (7 male, 11 female) typically developing (TD) children (ages 6-12; mean age 9.16 years). Both groups completed a battery of assessments that included motor coordination, sensory responsivity, receptive language, non-verbal reasoning and social communication measures Children with ASC also completed the Autism Diagnostic Observation Schedule and Autism Diagnostic Interview – Revised.. Results showed that children with ASC scored significantly lower on receptive language, coordination and sensory responsivity and a sensorimotor subscale, Modulation of Activity (MoA) compared to the TD group. In the ASC group, MoA significantly predicted ASC severity across all ASC measures; receptive language and sensory responsivity significantly predicted parental reported autism measures; and coordination significantly predicted examiner observed reported scores. Additionally, specific associations were found between the somatosensory perceptive modalities and ASC severity. The results show that sensorimotor skills are associated with severity of ASC symptoms; furthering the need to research sensorimotor integration in ASC and also implying that diagnosis of ASC should also include the assessment of both coordination deficit and atypical sensory responsivity

The Role of Sensorimotor Difficulties in Autism Spectrum Conditions

AbstractIn addition to difficulties in social communication, current diagnostic criteria for autism spectrum conditions (ASC) also incorporate sensorimotor difficulties; repetitive motor movements and atypical reactivity to sensory input (APA, 2013). This paper explores whether sensorimotor difficulties are associated with the development and maintenance of symptoms in ASC. Firstly, studies have shown difficulties coordinating sensory input into planning and executing movement effectively in ASC. Secondly, studies have shown associations between sensory reactivity and motor coordination with core ASC symptoms, suggesting these areas each strongly influence the development of social and communication skills. Thirdly, studies have begun to demonstrate that sensorimotor difficulties in ASC could account for reduced social attention early in development, with a cascading effect on later social, communicative and emotional development. These results suggest that sensorimotor difficulties not only contribute to non-social difficulties such as narrow circumscribed interests, but also to the development of social behaviours such as effectively coordinating eye contact with speech and gesture, interpreting others’ behaviour and responding appropriately. Further research is needed to explore the link between sensory and motor difficulties in ASC, and their contribution to the development and maintenance of ASC