Institut des Sciences de l'Information et de leurs Interactions

As time-sensitive networks must guarantee the end-to-end delay requirement of data flows, the worst-case delay (WCD) analysis is mandatory. To date, several analytical approaches have been proposed for WCD analysis, mainly in two classes: network-calculus approaches (NC), and real-time scheduling-oriented approaches such as response-time analysis (RTA), and compositional performance analysis (CPA). In spite of advances in WCD analysis techniques, the computation of the exact worst-case delay faces combinatorial explosion issues, therefore several approaches have been developed to provide an upper bound with more or less pessimism. Nevertheless, reducing pessimism remains challenging, and each approach differs from others in specific scenarios. In this context, this paper provides a comprehensive comparative study that analyzes the results of WCD calculation approaches under the Non-preemptive Fixed Priority Scheduling Policy. To further reduce the pessimism, we propose a new algorithm BWE (Blocking-Waived Estimation) built for switched network architectures upon RTA, which further investigates the relationship between blocking time and transmission time of the flow of interest (e.g., virtual link in AFDX) in adjacent hops. As illustrated in an example network architecture, the result produced by BWE is generally less pessimistic (the WCD is reduced by at maximum 34.34%) compared to the state-of-the-art RTA/CPA calculation results.

Given a rooted, binary phylogenetic network and a rooted, binary phylogenetic tree, can the tree be embedded into the network? This problem, called \textsc{Tree Containment}, arises when validating networks constructed by phylogenetic inference methods.We present the first algorithm for (rooted) \textsc{Tree Containment} using the treewidth $t$ of the input network $N$ as parameter, showing that the problem can be solved in $2^{O(t^2)}\cdot|N|$ time and space.

It has been over a decade since the first publication of a method dedicated entirely to mapping long-reads. The distinctive characteristics of long reads resulted in methods moving from the seed-and-extend framework used for short reads to a seed-and-chain framework due to the seed abundance in each read. The main novelties are based on alternative seed constructs or chaining formulations. Dozens of tools now exist, whose heuristics have evolved considerably. We provide an overview of the methods used in long-read mappers. Since they are driven by implementation-specific parameters, we develop an original visualization tool to understand the parameter settings (http://bcazaux.polytech-lille.net/Minimap2/).

RÉSUMÉ. L'analyse des avis (commentaires) générés par les utilisateurs devient de plus en plus exploitable par une variété d'applications. Elle permet de suivre l'évolution des avis ou d'effec- tuer des enquêtes sur des produits. La détection d'avis contradictoires autour d'une ressource Web (ex. cours, film, produit, etc.) est une tâche importante pour évaluer cette dernière. Dans cet article, nous nous concentrons sur le problème de détection des contradictions et de la me- sure de leur intensité en se basant sur l'analyse du sentiment autour des aspects spécifiques à une ressource (document). Premièrement, nous identifions certains aspects, selon les distri- butions des termes émotionnels au voisinage des noms les plus fréquents dans l'ensemble des commentaires. Deuxièmement, nous estimons la polarité de chaque segment de commentaire contenant un aspect. Ensuite, nous prenons uniquement les ressources contenant ces aspects avec des polarités opposées (positive, négative). Troisièmement, nous introduisons une mesure de l'intensité de la contradiction basée sur la dispersion conjointe de la polarité et du rating des commentaires contenant les aspects au sein de chaque ressource. Nous évaluons l'effica- cité de notre approche sur une collection de MOOC (Massive Open Online Courses) contenant 2244 cours et leurs 73873 commentaires, collectés à partir de Coursera. Nos résultats montrent l'efficacité de l'approche proposée pour capturer les contradictions de manière significative.