Wahrnehmung von Zusammenhalt aus Sicht von Menschen mit und ohne Behinderungserfahrungen. Erhebungsdesign und erste (Lern-)Erfahrungen des Projekts ZuSicht

Presentation (2023, February)

DenseQMC: an efficient bit-slice implementation of the Quine-McCluskey algorithm

E-print/Working paper (2023)

This note describes a new efficient bit-slice implementation DenseQMC of the Quine-McCluskey algorithm for finding all prime implicants of a Boolean function in the dense case. It is practically feasible ... [more ▼]

This note describes a new efficient bit-slice implementation DenseQMC of the Quine-McCluskey algorithm for finding all prime implicants of a Boolean function in the dense case. It is practically feasible for n <= 23 when run on a common laptop or for n <= 27 when run on a server with 1 TiB RAM. This note also outlines a very common mistake in the implementations of the Quine-McCluskey algorithm, leading to a quadratic slowdown. An optimized corrected implementation of the classic approach is also given (called SparseQMC). The implementation is freely available at https://github.com/hellman/Quine-McCluskey . [less ▲]

Consonant and Dissonant Experiences—Young Migrants’ Un-derstandings of Integration: A Cross-Country Comparison between Germany, Luxembourg, and Norway.

in Social Sciences (2023), 12

Our article addresses two aspects of young migrants’ understandings of integration: their own ideas of what integration is, and their perception of the destination society’s concepts and expectations ... [more ▼]

Our article addresses two aspects of young migrants’ understandings of integration: their own ideas of what integration is, and their perception of the destination society’s concepts and expectations regarding their integration. We analyze qualitative interviews which were conducted in the Horizon 2020 project MIMY, in Germany, Luxembourg and Norway, using the grounded theory methodology. Our exploration shows that the young migrants’ awareness of the existing ideas of integration surrounding them creates a complex reflective interaction between their own ideas and the (perceived) expectations from society. We identified aspects of consonance, where young migrants’ ideas coincide with the expectations they perceive. More importantly, however, our research has discovered that the youth experience tensions and dissonance between their own ideas of what integration should be and the concepts and expectations regarding integration they feel confronted with by society. Our analysis revealed that while young migrants’ understandings of integration are very close to state-of-the-art scientific conceptualizations of integration, this view is not matched by the meaning of integration they perceive around them. [less ▲]

Applications of Boolean modelling to study and stratify dynamics of a complex disease

Doctoral thesis (2023)

Interpretation of omics data is needed to form meaningful hypotheses about disease mechanisms. Pathway databases give an overview of disease-related processes, while mathematical models give qualitative ... [more ▼]

Interpretation of omics data is needed to form meaningful hypotheses about disease mechanisms. Pathway databases give an overview of disease-related processes, while mathematical models give qualitative and quantitative insights into their complexity. Similarly to pathway databases, mathematical models are stored and shared on dedicated platforms. Moreover, community-driven initiatives such as disease maps encode disease-specific mechanisms in both computable and diagrammatic form using dedicated tools for diagram biocuration and visualisation. To investigate the dynamic properties of complex disease mechanisms, computationally readable content can be used as a scaffold for building dynamic models in an automated fashion. The dynamic properties of a disease are extremely complex. Therefore, more research is required to better understand the complexity of molecular mechanisms, which may advance personalized medicine in the future. In this study, Parkinson’s disease (PD) is analyzed as an example of a complex disorder. PD is associated with complex genetic, environmental causes and comorbidities that need to be analysed in a systematic way to better understand the progression of different disease subtypes. Studying PD as a multifactorial disease requires deconvoluting the multiple and overlapping changes to identify the driving neurodegenerative mechanisms. Integrated systems analysis and modelling can enable us to study different aspects of a disease such as progression, diagnosis, and response to therapeutics. Therefore, more research is required to better understand the complexity of molecular mechanisms, which may advance personalized medicine in the future. Modelling such complex processes depends on the scope and it may vary depending on the nature of the process (e.g. signalling vs metabolic). Experimental design and the resulting data also influence model structure and analysis. Boolean modelling is proposed to analyse the complexity of PD mechanisms. Boolean models (BMs) are qualitative rather than quantitative and do not require detailed kinetic information such as Petri nets or Ordinary Differential equations (ODEs). Boolean modelling represents a logical formalism where available variables have binary values of one (ON) or zero (OFF), making it a plausible approach in cases where quantitative details and kinetic parameters 9 are not available. Boolean modelling is well validated in clinical and translational medicine research. In this project, the PD map was translated into BMs in an automated fashion using different methods. Therefore, the complexity of disease pathways can be analysed by simulating the effect of genomic burden on omics data. In order to make sure that BMs accurately represent the biological system, validation was performed by simulating models at different scales of complexity. The behaviour of the models was compared with expected behavior based on validated biological knowledge. The TCA cycle was used as an example of a well-studied simple network. Different scales of complex signalling networks were used including the Wnt-PI3k/AKT pathway, and T-cell differentiation models. As a result, matched and mismatched behaviours were identified, allowing the models to be modified to better represent disease mechanisms. The BMs were stratified by integrating omics data from multiple disease cohorts. The miRNA datasets from the Parkinson’s Progression Markers Initiative study (PPMI) were analysed. PPMI provides an important resource for the investigation of potential biomarkers and therapeutic targets for PD. Such stratification allowed studying disease heterogeneity and specific responses to molecular perturbations. The results can support research hypotheses, diagnose a condition, and maximize the benefit of a treatment. Furthermore, the challenges and limitations associated with Boolean modelling in general were discussed, as well as those specific to the current study. Based on the results, there are different ways to improve Boolean modelling applications. Modellers can perform exploratory investigations, gathering the associated information about the model from literature and data resources. The missing details can be inferred by integrating omics data, which identifies missing components and optimises model accuracy. Accurate and computable models improve the efficiency of simulations and the resulting analysis of their controllability. In parallel, the maintenance of model repositories and the sharing of models in easily interoperable formats are also important. [less ▲]

Commercial Space Operators on the Digital Battlefield

in CIGI Essay Series: Cybersecurity and Outer Space (2023)

La Grande Stratégie des petites puissances – Etude des mécanismes de fondation d’une grande stratégie face à un dilemme de sécurité appliqués au Luxembourg, à la Lituanie et à Singapour (1965-2025)-

Doctoral thesis (2023)

The capacity of small powers to think strategically remains a limited field of interest in historical thinking and international relations. Thus, beyond the debate concerning the capacity of small states ... [more ▼]

The capacity of small powers to think strategically remains a limited field of interest in historical thinking and international relations. Thus, beyond the debate concerning the capacity of small states to be full-fledged actors in the international system, there appears to be a denial of the conceptualization and doctrinal innovation capacity of small powers despite the historical redundancy of the victory of the weak over the strong. However, small powers are by nature more sensitive to threats due to their limited response capabilities, and are therefore more inclined to rationalize their action over the long term in order to develop national (military, economic, diplomatic capabilities, etc.) and international (alliances, international organizations, etc.) mechanisms for containing these threats. In this respect, this thesis proposes to look at the construction of the strategic thinking of small powers in the face of perceived threats and the means used to try to contain them. The aim is therefore to study the mechanisms by which small powers found a Grand Strategy (transcribed in the form of doctrines) to deal with the security dilemmas they face. To this end, three case studies were analyzed (Luxembourg, Singapore, Lithuania), chosen for the diversity of their strategic and historical contexts offering a variety of security dilemmas. The Grand Strategy being in essence a conceptual construction with a prospective and applicative aim, a theoretical as well as a practical methodology (through the use of immediate history and wargaming) was then implemented. Two sets of lessons can be drawn from this thesis. The first is methodological, confirming the interest of doctrinal studies as a field of strategic reflection, and establishing wargaming as a prospective tool adapted to the conduct of fundamental research. The second, conceptual, allows for a better understanding of the capacity of small powers to create great and efficient strategies, which must be taken into account within the strategic genealogy because of their conceptual dynamism, which can be used to teach lessons even to great powers. [less ▲]

The Ostarbeiters in Belval

in Egberdien, van der Peijl (Ed.) Artistic Performance about the Ostarbeiters in Belval 1942-1944 (2023)

Egberdien van der Peijl presented some artworks based on the ZWANG-proeject photograph sollection of the Ostarbeiters, made on the forced labourer camp sites and or in the steel mills together with DJ ... [more ▼]

Egberdien van der Peijl presented some artworks based on the ZWANG-proeject photograph sollection of the Ostarbeiters, made on the forced labourer camp sites and or in the steel mills together with DJ Yoni. The musical improvisation together with a theatrically played performance imitated the life of an Ostarbeiter in the gallery's basements. The venue was Fellner Contemporary in the city. [less ▲]

Planktonic Active Matter

E-print/Working paper (2023)

Planktonic active matter represents an emergent system spanning different scales: individual, population and community; and complexity arising from sub-cellular and cellular to collective and ecosystem ... [more ▼]

Planktonic active matter represents an emergent system spanning different scales: individual, population and community; and complexity arising from sub-cellular and cellular to collective and ecosystem scale dynamics. This cross-scale active matter system responds to a range of abiotic (temperature, fluid flow and light conditions) and biotic factors (nutrients, pH, secondary metabolites) characteristic to the relevant ecosystems they are part of. Active modulation of cell phenotypes, including morphology, motility, and intracellular organization enable planktonic microbes to dynamically interact with other individuals and species; and adapt - often rapidly - to the changes in their environment. In this chapter, I discuss both traditional and contemporary approaches to study the dynamics of this multi-scale active matter system from a mechanistic standpoint, with specific references to their local settings and their ability to actively tune the behaviour and physiology, and the emergent structures and functions they elicit under natural ecological constraints as well as due to the shifting climatic trends. [less ▲]

REVISITING AND BOOSTING STATE-OF-THE-ART ML-BASED ANDROID MALWARE DETECTORS

Doctoral thesis (2023)

Android offers plenty of services to mobile users and has gained significant popularity worldwide. The success of Android has resulted in attracting more mobile users but also malware authors. Indeed ... [more ▼]

Android offers plenty of services to mobile users and has gained significant popularity worldwide. The success of Android has resulted in attracting more mobile users but also malware authors. Indeed, attackers target Android markets to spread their malicious apps and infect users’ devices. The consequences vary from displaying annoying ads to gaining financial benefits from users. To overcome the threat posed by Android malware, Machine Learning has been leveraged as a promising technique to automatically detect malware. The literature on Android malware detection lavishes with a huge variety of ML-based approaches that are designed to discriminate malware from legitimate samples. These techniques generally rely on manually engineered features that are extracted from the apps’ artefacts. Reported to be highly effective, Android malware detection approaches seem to be the magical solution to stop the proliferation of malware. Unfortunately, the gap between the promised and the actual detection performance is far from negligible. Despite the rosy excellent detection performance painted in the literature, the detection reports show that Android malware is still spreading and infecting mobile users. In this thesis, we investigate the reasons that impede state-of-the-art Android malware detection approaches to surround the spread of Android malware and propose solutions and directions to boost their detection performance. In the first part of this thesis, we focus on revisiting the state of the art in Android malware detection. Specifically, we conduct a comprehensive study to assess the reproducibility of state-of-the-art Android malware detectors. We consider research papers published at 16 major venues over a period of ten years and report our reproduction outcome. We also discuss the different obstacles to reproducibility and how they can be overcome. Then, we perform an exploratory analysis on a state-of-the-art malware detector, DREBIN, to gain an in-depth understanding of its inner working. Our study provides insights into the quality of DREBIN’s features and their effectiveness in discriminating Android malware. In the second part of this thesis, we investigate novel features for Android malware detection that do not involve manual engineering. Specifically, we propose an Android malware detection approach, DexRay, that relies on features extracted automatically from the apps. We convert the raw bytecode of the app DEX files into an image and train a 1-dimensional convolutional neural network to automatically learn the relevant features. Our approach stands out for the simplicity of its design choices and its high detection performance, which make it a foundational framework for further developing this domain. In the third part, we attempt to push the frontier of Android malware detection via enhancing the detection performance of the state of the art. We show through a large-scale evaluation of four state-of-the-art malware detectors that their detection performance is highly dependent on the experimental dataset. To solve this issue, we investigate the added value of combining their features and predictions using 22 combination methods. While it does not improve the detection performance reported by individual approaches, the combination of features and predictions maintains the highest detection performance independently of the dataset. We further propose a novel technique, Guided Retraining, that boosts the detection performance of state-of-the-art Android malware detectors. Guided Retraining uses contrastive learning to learn a better representation of the difficult samples to improve their prediction. [less ▲]

Soil viral particles as tracers of surface water sources and flow paths

Doctoral thesis (2023)

Albeit recent technological developments (e.g. field deployable instruments operating at high temporal frequencies), experimental hydrology is a discipline that remains measurement limited. From this ... [more ▼]

Albeit recent technological developments (e.g. field deployable instruments operating at high temporal frequencies), experimental hydrology is a discipline that remains measurement limited. From this perspective, trans-disciplinary approaches may create valuable opportunities to enlarge the number of tools available for investigating hydrological processes. Tracing experiments are usually performed in order to investigate the water flow pathways and water sources in underground areas. Since the 19th century, researchers have worked with hydrological tracers to do this. Among them, the fluorescent dyes and the isotopes are the most commonly used to follow the water flow while others like salts or bacteriophages are employed as additional tracers to those mentioned above. Bacteriophages are the least known of all, but it has been studied since the 1960s as hydrological tracers, especially in karstic environments. The purpose is to evaluate the potential for bacteriophages naturally occurring in soils to serve as a new environmental tracer of hydrological processes. We hypothesize that such viral particles can be a promising tool in water tracing experiments since they are safe for ecosystems. In both fields of hydrology and virology, the knowledge regarding the fate of bacteriophages within the pedosphere is still limited. Their study would not only allow proposing potential new candidates to enlarge the hydrological tracers available, but also improving the current knowledge about the bacteriophage communities in soil and their interactions with certain environmental factors. For this purpose, we aim at describing the bacteriophage communities occurring in the soil through shotgun metagenomics analysis. Those viruses are widely spread in the pedosphere, and we assume that they have specific signatures according to the type of soil. Then, bacteriophage populations will be investigated in the soil water to analyse the dis/similarities between the two communities as well as their dynamics in the function of the precipitation events. This way, with a relatively high abundance of soil and soil water and a capacity of being mobilised, good bacteriophage candidates could be selected as hydrological tracers. [less ▲]