Publications

Energy problems in finite and timed automata with Büchi conditions

Abstract

We show how to efficiently solve energy Büchi problems in finite weighted automata and in one-clock weighted timed automata. Solving the former problem is our main contribution and is handled by a modified version of Bellman-Ford interleaved with Couvreur’s algorithm. The latter problem is handled via a reduction to the former relying on the corner-point abstraction. All our algorithms are freely available and implemented in a tool based on the open-source tools TChecker and Spot.

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Higher-dimensional timed and hybrid automata

Abstract

We introduce a new formalism of higher-dimensional timed automata, based on Pratt and van Glabbeek’s higher-dimensional automata and Alur and Dill’s timed automata. We prove that their reachability is PSPACE-complete and can be decided using zone-based algorithms. We also extend the setting to higher-dimensional hybrid automata. The interest of our formalism is in modeling systems which exhibit both real-time behavior and concurrency. Other existing formalisms for real-time modeling identify concurrency and interleaving, which, as we shall argue, is problematic.

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Introduction to the special issue on distributed hybrid systems

Abstract

This special issue contains seven papers within the broad subject of Distributed Hybrid Systems, that is, systems combining hybrid discrete-continuous state spaces with elements of concurrency and logical or spatial distribution. It follows up on several workshops on the same theme which were held between 2017 and 2019 and organized by the editors of this volume. The first of these workshops was held in Aalborg, Denmark, in August 2017 and associated with the MFCS conference. It featured invited talks by Alessandro Abate, Martin Fränzle, Kim G. Larsen, Martin Raussen, and Rafael Wisniewski. The second workshop was held in Palaiseau, France, in July 2018, with invited talks by Luc Jaulin, Thao Dang, Lisbeth Fajstrup, Emmanuel Ledinot, and André Platzer. The third workshop was held in Amsterdam, The Netherlands, in August 2019, associated with the CONCUR conference. It featured a special theme on distributed robotics and had invited talks by Majid Zamani, Hervé de Forges, and Xavier Urbain. The vision and purpose of the DHS workshops was to connect researchers working in real-time systems, hybrid systems, control theory, formal verification, distributed computing, and concurrency theory, in order to advance the subject of distributed hybrid systems. Such systems are abundant and often safety-critical, but ensuring their correct functioning can in general be challenging. The investigation of their dynamics by analysis tools from the aforementioned domains remains fragmentary, providing the rationale behind the workshops: it was conceived that convergence and interaction of theories, methods, and tools from these different areas was needed in order to advance the subject.

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An efficient cascade of U-Net-like convolutional neural networks devoted to brain tumor segmentation

Abstract

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The Dahu graph-cut for interactive segmentation on 2D/3D images

Abstract

Interactive image segmentation is an important application in computer vision for selecting objects of interest in images. Several interactive segmentation methods are based on distance transform algorithms. However, the most known distance transform, geodesic distance, is sensitive to noise in the image and to seed placement. Recently, the Dahu pseudo-distance, a continuous version of the minimum barrier distance (MBD), is proved to be more powerful than the geodesic distance in noisy and blurred images. This paper presents a method for combining the Dahu pseudo-distance with edge information in a graph-cut optimization framework and leveraging each’s complementary strengths. Our method works efficiently on both 2D/3D images and videos. Results show that our method achieves better performance than other distance-based and graph-cut methods, thereby reducing the user’s efforts.

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Blockchain-based solution for detecting and preventing fake check scams

Abstract

Fake check scam is one of the most common attacks used to commit fraud against consumers. This fraud is particularly costly for victims because they generally lose thousands of dollars as well as being exposed to judicial proceedings. Currently, there is no existing solution to authenticate checks and detect fake ones instantly. Instead, banks must wait for a period of more than 48 h to detect the scam. In this context, we propose a blockchain-based scheme to authenticate checks and detect fake check scams. Moreover, our approach allows the revocation of used checks. More precisely, our approach helps the banks to share information about provided checks and used ones, without exposing the banks’ customers’ personal data. We demonstrate a proof of concept of our proposed approach using Namecoin and Hyperledger blockchain technologies.

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Pictograms to aid laypeople in identifying the addictiveness of gambling products (PictoGRRed study)

Abstract

The structural addictive characteristics of gambling products are important targets for prevention, but can be unintuitive to laypeople. In the PictoGRRed (Pictograms for Gambling Risk Reduction) study, we aimed to develop pictograms that illustrate the main addictive characteristics of gambling products and to assess their impact on identifying the addictiveness of gambling products by laypeople. We conducted a three-step study: (1) use of a Delphi consensus method among 56 experts from 13 countries to reach a consensus on the 10 structural addictive characteristics of gambling products to be illustrated by pictograms and their associated definitions, (2) development of 10 pictograms and their definitions, and (3) study in the general population to assess the impact of exposure to the pictograms and their definitions (n = 900). French-speaking experts from the panel assessed the addictiveness of gambling products (n = 25), in which the mean of expert’s ratings was considered as the true value. Participants were randomly provided with the pictograms and their definitions, or with a standard slogan, or with neither (control group). We considered the control group as representing the baseline ability of laypeople to assess the addictiveness of gambling products. Each group and the French-speaking experts rated the addictiveness of 14 gambling products. The judgment criterion was the intraclass coefficients (ICCs) between the mean ratings of each group and the experts, reflecting the level of agreement between each group and the experts. Exposure to the pictograms and their definition doubled the ability of laypeople to assess the addictiveness of gambling products compared with that of the group that read a slogan or the control group (ICC = 0.28 vs. 0.14 (Slogan) and 0.14 (Control)). Laypeople have limited awareness of the addictive characteristics of gambling products. The pictograms developed herein represent an innovative tool for universally empowering prevention and for selective prevention.

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PKIs in C-ITS: Security functions, architectures and projects: A survey

Abstract

In the smart cities context, Cooperative Intelligent Transportation Systems (C-ITS) represent one of the main use cases that aim to improve peoples’ daily lives. Within these environments, messages are exchanged continuously. The latter must be secure and must ensure users’ privacy. In this regard, Public Key Infrastructures (PKIs) represent the major solution to meet security needs. In this work, we present a holistic survey that describes all the different functions and services of a C-ITS PKI and focus on the different standards and consortia works that have been adopted to regulate such PKIs. Relying on the survey, we highlight the main research problems and open challenges for ITS PKIs. Then, we propose a generic model for a C-ITS PKI architecture.

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Featured games

Abstract

Feature-based analysis of software product lines and family-based model checking have seen rapid development. Many model checking problems can be reduced to two-player games on finite graphs. A prominent example is mu-calculus model checking, which is generally done by translating to parity games, but also many quantitative model-checking problems can be reduced to (quantitative) games. As part of a program to make game-based model checking available for software product lines, we introduce featured reachability games, featured minimum reachability games, featured discounted games, featured energy games, and featured parity games. We show that all these admit optimal featured strategies, which project to optimal strategies for any product, and how to compute winners and values of such games in a family-based manner.

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GenIDA: An international participatory database to gain knowledge on health issues related to genetic forms of neurodevelopmental disorders

Abstract

Intellectual disability with or without manifestations of autism and/or epilepsy affects 1-2% of the population, and it is estimated that more than 30-50% of these cases have a single genetic cause. More than 1000 genes and recurrent chromosomal abnormalities are involved in these genetic forms of neurodevelopmental disorders, which often remain insufficiently described in terms of clinical spectrum, associated medical problems, etc., due to their rarity and the often-limited number of patients’ phenotypes reported. GenIDA is an international online participatory database that aims to better characterise the clinical manifestations and natural histories of these rare diseases. Clinical information is reported by parents of affected individuals using a structured questionnaire exploring physical parameters, cognitive and behavioural aspects, the presence or absence of neurological disorders or problems affecting major physiological functions, as well as autonomy and quality of life. This strengthens the implication in research of the concerned families. GenIDA aims to construct international cohorts of significant size of individuals affected by a given condition. As of July 2022, GenIDA counts some 1545 documented patient records from over 60 nationalities and collaborates with clinicians and researchers around the world who have access to the anonymized data collected to generate new, medically meaningful information to improve patient care. We present the GenIDA database here, together with an overview of the possibilities it offers to affected individuals, their families, and professionals in charge of the management of genetic forms of neurodevelopmental disorders. Finally, case studies of cohorts will illustrate the usefulness of GenIDA.

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