Verification of design models of cyber-physical systems specified in Simulink

Doctoral thesis (2021)

Recent advances in cyber-physical systems (CPS) have allowed highly available and approachable technologies with interconnected systems between the physical assets and the computational software ... [more ▼]

Recent advances in cyber-physical systems (CPS) have allowed highly available and approachable technologies with interconnected systems between the physical assets and the computational software components. This has resulted in more complex systems with wider capabilities. For example, they can be applied in various domains such as safe transport, efficient medical devices, integrated systems, critical infrastructure control and more. The development of such critical systems requires advanced new models, algorithms, methods and tools to verify and validate the software components and the entire system. The verification of cyber-physical systems has become challenging: (1) The complex and dynamical behaviour of systems requires resilient automated monitors and test oracles that can cope with time-varying variables of CPS. (2) Given the wide range of existing verification and testing techniques from formal to empirical methods, there is no clear guidance as to how different techniques fare in the context of CPS. (3) Due to serious issues when applying exhaustive verification to complex systems, a common practice is needed to verify system components separately. This requires adding implicit assumptions about the operational environment of system components to ensure correct verification. However, identifying environment assumptions for cyber-physical systems with complex, mathematical behaviors is not trivial. In this dissertation, we focus on addressing these challenges. In this dissertation, we propose a set of effective approaches to verify design models of CPS. The work presented in this dissertation is motivated by ESAIL maritime micro-satellite system, developed by LuxSpace, a leading provider of space systems, applications and services in Luxembourg. In addition to ESAIL, we use a benchmark of eleven public-domain Simulink models provided by Lockheed Martin, which are representative of different categories of CPS models in the aerospace and defence sector. To address the aforementioned challenges, we propose (1) an automated approach to translate CPS requirements specified in a logic-based language into test oracles specified in Simulink. The generated oracles are able to deal with CPS complex behaviours and interactions with the system environment; (2) An empirical study to evaluate the fault-finding capabilities of model testing and model checking techniques for Simulink models. We also provide a categorization of model types and a set of common logical patterns for CPS requirements; (3) An automated approach to synthesize environment assumptions for a component under analysis by combining search-based testing, machine learning and model checking procedures. We also propose a novel technique to guide the test generation based on the feedback received from the machine learning process; and (4) An extension of (3) to learn more complex assumptions with arithmetic expressions over multiple signals and numerical variables. [less ▲]

QKD parameter estimation by two-universal hashing leads to faster convergence to the asymptotic rate

E-print/Working paper (2021)

This paper proposes and proves security of a QKD protocol which uses two-universal hashing instead of random sampling to estimate the number of bit flip and phase flip errors. For this protocol, the ... [more ▼]

This paper proposes and proves security of a QKD protocol which uses two-universal hashing instead of random sampling to estimate the number of bit flip and phase flip errors. For this protocol, the difference between asymptotic and finite key rate decreases with the number $n$ of qubits as $cn^{-1}$, where $c$ depends on the security parameter. For comparison, the same difference decreases no faster than $c'n^{-1/3}$ for an optimized protocol that uses random sampling and has the same asymptotic rate, where $c'$ depends on the security parameter and the error rate. [less ▲]

Computational guided frameworks to identify signalling perturbations for cellular transitions: application to cellular conversion, disease and regeneration

Doctoral thesis (2021)

Outcomes of Inclusive Education: Investigating Students’ Social Inclusion, Emotional Inclusion and Academic Self-Concept [symposium discussant]

Scientific Conference (2021, September 08)

Élections fédérales 2021 : l’ère après-Merkel

Article for general public (2021)

Moral Judgment in Video Games: Effects of Medium, Moral Intuitions and Media-Based Empathy

Scientific Conference (2021, September)

An Integrative Model of Moral Processing for the Video Game Medium

Scientific Conference (2021, September)

Value Stream Mapping (VSM) to Evaluate and Visualize Interrelated Process-Chains Regarding Circular Economy

in Advances in Production Management Systems. Artificial Intelligence for Sustainable and Resilient Production Systems (2021, August 31), 633

The concept of circular economy (CE) aims to close and slow resource loops without neglecting the goals of sustainable development. Recently, the concept received encouraging attention among researchers ... [more ▼]

The concept of circular economy (CE) aims to close and slow resource loops without neglecting the goals of sustainable development. Recently, the concept received encouraging attention among researchers and business experts to be a convenient solution to move away from the finite linear economy concept to a more sustainable solution. However, this change of paradigm is only possible if we consider systems in a holistic manner and can localize the preventing hurdles. Value stream mapping (VSM) is a commonly known lean method, used to develop current state visualization of product and information flows within organization, helping to seek weaknesses and improve process flows. The motivation of this paper is a new C-VSM model, which enables its users to evaluate and visualize connected process-chains regarding CE on different levels in a holistic manner. For this purpose, the traditional VSM model was adapted towards the needs and requirements of CE through the application of a new representation method, additional indicators, and an appropriated evaluation system. C-VSM is in line with the current political and industrial objectives to apply CE principles by enabling a holistic reflection and consideration of supply-chains (SCs) on different levels. The model itself is validated through an extensive cross-company case study. [less ▲]

Normative coherence for development – What relevance for responsive regionalism?

in Development Policy Review (2021)

Without a normative dimension, transformative development risks reproducing traditional economic development. In this special issue we focus on norm implementation in different world regions through the ... [more ▼]

Without a normative dimension, transformative development risks reproducing traditional economic development. In this special issue we focus on norm implementation in different world regions through the lens of normative coherence for development. This special issue indicates that regions are an important interlocutor between the global, national, and sub-national level and, as such, are crucial for implementing the sustainable development agenda. The articles show, however, that to date normative coherence for development has not been achieved due to overriding priorities and technical approaches to policy coherence for development. With this special issue we aim to draw more attention to the topic of normative coherence for development and show that policies need to be adjusted in order to reflect the normative dimension of sustainable development. [less ▲]

Almost global convergence to practical synchronization in the generalized Kuramoto model on networks over the n-sphere

in Communications Physics (2021), 4

From the flashing of fireflies to autonomous robot swarms, synchronization phenomena are ubiquitous in nature and technology. They are commonly described by the Kuramoto model that, in this paper, we ... [more ▼]

From the flashing of fireflies to autonomous robot swarms, synchronization phenomena are ubiquitous in nature and technology. They are commonly described by the Kuramoto model that, in this paper, we generalise to networks over n-dimensional spheres. We show that, for almost all initial conditions, the sphere model converges to a set with small diameter if the model parameters satisfy a given bound. Moreover, for even n, a special case of the generalized model can achieve phase synchronization with nonidentical frequency parameters. These results contrast with the standard n = 1 Kuramoto model, which is multistable (i.e., has multiple equilibria), and converges to phase synchronization only if the frequency parameters are identical. Hence, this paper shows that the generalized network Kuramoto models for n ≥ 2 displays more coherent and predictable behavior than the standard n = 1 model, a desirable property both in flocks of animals and for robot control. [less ▲]