EphemeriShield - Defence Against Cyber-Antisatellite Weapons

Scientific Conference (2021, October 14)

Mitigating the risks associated with space system operations, especially in Low Earth Orbit, requires a holistic approach, which addresses, in particular, cybersecurity challenges, in addition to meeting ... [more ▼]

Mitigating the risks associated with space system operations, especially in Low Earth Orbit, requires a holistic approach, which addresses, in particular, cybersecurity challenges, in addition to meeting the data acquisition requirements the mission needs. Space traffic management systems form no exception to this rule, but are further constrained by backward compatibility requirements that sometimes are based on decades old foundations. As a result, some space situational awareness systems continue to operate with object catalogues and data dissemination architectures that are prone to failures, not to mention adversarial actions. Proof-of-Concept papers, demonstrating this vulnerability in example attacks on space object ephemerides distribution channels have already been published and show the urgency in rethinking the way we build such high-critical infrastructure. Leveraging recent developments of distributed systems theory and concepts from multi-party consensus in limited-trust environments and in the presence of malicious actors, we designed a more secure system for orbital object ephemerides distribution, ultimately targeting at increasing the safety of satellite operations. This paper presents EphemeriShield, a distributed ephemerides storage and distribution system, aiming at maintaining safety and security guarantees in presence of active attacker or unfortunate fault. Using our EphemeriShield prototype setup, we were able to prove its ability to mask attacks and local faults that otherwise would lead to unnecessary maneuvers. Wide adoption of EphemeriShield may help satellite system operations to become safer and less vulnerable to intentionally adversarial activities, which improves the overall sustainability of space. [less ▲]

Judicial Education and Judicial Independence: Paper given at the 2021 Commonwealth Law Conference

E-print/Working paper (2021)

The link between judicial education and an efficient judiciary is, one hopes, obvious. But in order to ensure judicial independence, contemporary wisdom has it, judicial education should also be in the ... [more ▼]

The link between judicial education and an efficient judiciary is, one hopes, obvious. But in order to ensure judicial independence, contemporary wisdom has it, judicial education should also be in the hands of the judiciary. Absent such control, there is a risk that judges may be indoctrinated by interested actors and their independence compromised. Some critics, however, have been sceptical about judicial control of judicial education. Judicial control of education often justified on basis of expertise as well as need to protect independence. But judges are not pedagogues (and their view of what judging does, or should, entail are often untheorized). Nor are they particularly representative of society. In addition, a danger unmitigated by judicial control of judicial education is regulatory capture, defined as ‘the result or process by which regulation, in law or application, is consistently or repeatedly directed away from the public interest and toward the interests of the regulated industry, by the intent and action of the industry itself'. Even if other voices are integrated into discussions, the danger exists that they might seek to subvert the process to privilege their interests over the general interest. Such concerns have recently been raised in England and Wales with regard to the Equal Treatment Bench Book. The paper examines the relationship between judicial education and judicial independence through the lens of this controversy. It concludes that when judicial education trespass on the independence of the individual judge is not an easy question to answer (not least because education is always about socialization) but, crucially, it is not one answered by putting judicial education in the hands of the judiciary. [less ▲]

From Tool to Experience: Establishing a User Experience Perspective on Digital Concept Mapping

Doctoral thesis (2021)

Education today faces difficult challenges, particularly because the complexity of topics or problems is rising and requires that learners see connections across different domain boundaries. Consequently ... [more ▼]

Education today faces difficult challenges, particularly because the complexity of topics or problems is rising and requires that learners see connections across different domain boundaries. Consequently, learners and instructors need a systematic approach to build and assess structural knowledge, supporting them to work with complexity in the 21st century. Digital concept mapping is a promising method to address these challenges. Concept maps are graphical networks of concepts and links with a particular emphasis on explicit semantic relations. Digitalization of concept mapping offers a range of capabilities but also adds challenges of its own. As learners take on a simultaneous role of users, the question of how to purposefully design positive experiences in digital concept mapping becomes a key concern. A digital tool needs to be optimized to allow learners to focus on task-relevant aspects instead of investing cognitive resources into operating the tool. Furthermore, a digital tool can itself be a source of positive experiences, contributing to motivation and reaching the overall educational goals. With an insufficient focus on users, designers and researchers risk creating tools that do not adequately acknowledge the aforementioned impacts on education. The present dissertation argues that the notion of user experience (UX) is adequate for investigating and purposefully shaping learner experiences with concept maps. The dissertation addresses the following research question: How does a user experience-driven approach contribute to digital concept mapping? After a general introduction (Part I), the dissertation builds on eight studies in four main parts: defining objectives of user experience design for digital concept mapping (Part II), investigating user experience design for a digital concept mapping tool (Part III), identifying scoring approaches for concept map-based assessment (Part IV), and investigating the impact of user experience on digital concept mapping (Part V). It concludes with a general discussion (Part VI). Part II presents three studies. Chapter 2 describes a co-design study in four classes. It combined functionality-driven and experience-driven design and identified a requirements profile for a digital concept mapping tool. Chapter 3 describes a storytelling focus group study that identified the role, desired outcomes, and pain points of digital concept mapping in Luxembourgish secondary education. Chapter 4 describes an interview study that identified how digital concept mapping contributes to fulfilling psychological needs. Part III describes the user experience design of a digital concept mapping tool. Chapters 6, 7, 8, and 9 investigate and optimize user experience with a concept mapping tool, building on a combination of critical incidents, think-aloud, card-driven investigation of psychological needs, and interviews. In summary, these studies were able to optimize user experience in digital concept mapping. Part IV addresses the scoring of concept maps which was identified as a key challenge for instructors and researchers in Part II. Chapter 10 is a systematic literature review of criteria used to score concept maps, resulting in a comprehensive framework with three dimensions that define concept map scoring. Finally, Part V presents two studies measuring the impact of a user experience perspective on digital concept mapping. Chapter 11 investigates user experience, psychological needs, intention to use, and concept map scores. Psychological needs strongly determined positive user experience, but not universally across all needs. User experience strongly impacted intention to use. Furthermore, our results indicated the need for further research into the relation between user experience and scores. Chapter 12 presents work in progress on guidelines and a scoring rubric for the meaningful use of multimodal features (like color, shape, or line type) in digital concept mapping. The present dissertation contributes empirical results to establishing a user experience perspective by identifying functional and non-functional goals, contextual factors, desired outcomes, pain points, and functionalities and characteristics of digital concept mapping tools. Furthermore, it outlines how these requirements can be achieved with UX design. The dissertation also contributes theoretical and meta-analytical findings by proposing a profile of psychological needs for concept mapping and deriving a comprehensive framework of criteria used to score concept maps. Finally, the dissertation makes methodological contributions by demonstrating how humans can be systematically involved in shaping their experiences with digital concept maps. The dissertation also provides recommendations for future design and instruction. [less ▲]

OZONE GAS SENSORS BASED ON OFF-STOICHIOMETRIC COPPER-CHROMIUM-OXIDE THIN FILMS

Doctoral thesis (2021)

Ozone is a major concern for indoor office pollution. Recurring exposure to low levels of ozone (in ppb range) can be associated with several cardiopulmonary diseases. As such, there is a need for cheap ... [more ▼]

Ozone is a major concern for indoor office pollution. Recurring exposure to low levels of ozone (in ppb range) can be associated with several cardiopulmonary diseases. As such, there is a need for cheap, easy-to-integrate ozone gas sensors that can achieve good performance and work as an alarm for dangerous ozone concentrations. In this work, we propose the use of off-stoichiometric copper-chromium-oxide, that has shown great reversible measurements at low temperature for ozone detection, as low as 50 ppb. The selectivity compared with molecular oxygen is shown. Near-Atmospheric Pressure X-Ray Photoelectron Spectroscopy led to the understanding of the ozone - delafossite surface reaction. This work discloses pioneering results in the fabrication of low cost, high sensitivity ozone sensors based on a p-type material. [less ▲]

Organiser and Chair: Temporalities and migratory border-crossings in literature and other discourse (Prof. Dr. Johan Schimanski)

Presentation (2021, October 12)

Near surface defects: Cause of deficit between internal and external open-circuit voltage in solar cells

in Progress in Photovoltaics (2021)

Interface recombination in a complex multilayered thin-film solar structure causes a disparity between the internal open-circuit voltage (VOC,in), measured by photoluminescence, and the external open ... [more ▼]

Interface recombination in a complex multilayered thin-film solar structure causes a disparity between the internal open-circuit voltage (VOC,in), measured by photoluminescence, and the external open-circuit voltage (VOC,ex), that is, a VOC deficit. Aspirations to reach higher VOC,ex values require a comprehensive knowledge of the connection between VOC deficit and interface recombination. Here, a near-surface defect model is developed for copper indium di-selenide solar cells grown under Cu-excess conditions. These cell show the typical signatures of interface recombination: a strong disparity between VOC,in and VOC,ex, and extrapolation of the temperature dependent q·VOC,ex to a value below the bandgap energy. Yet, these cells do not suffer from reduced interface bandgap or from Fermi-level pinning. The model presented is based on experimental analysis of admittance and deep-level transient spectroscopy, which show the signature of an acceptor defect. Numerical simulations using the near-surface defects model show the signatures of interface recombination without the need for a reduced interface bandgap or Fermi-level pinning. These findings demonstrate that the VOC,in measurements alone can be inconclusive and might conceal the information on interface recombination pathways, establishing the need for complementary techniques like temperature dependent current–voltage measurements to identify the cause of interface recombination in the devices. [less ▲]

Recension d' European Drama and Performance Studies n° 16 : « Percevoir et transmettre le spectacle vivant »

Scientific Conference (2021, October 11)

Cette recension, divisée en trois temps, va suivre les différents points de vue adoptés par les participants au seizième numéro de la revue European Drama and Performance Studies, consacré à la perception ... [more ▼]

Cette recension, divisée en trois temps, va suivre les différents points de vue adoptés par les participants au seizième numéro de la revue European Drama and Performance Studies, consacré à la perception et à la transmission du spectacle vivant et dirigé par Françoise Gomez et Daniel Loayza : 1. Le regard du chercheur (Florence Naugrette, Julia Gros de Gasquet et Patrice Pavis) ; 2. Le regard du praticien de la scène (Emmanuel Demarcy-Mota et Don Kent) ; 3. L’archivage mémoriel (Sandrine Siméon et Daniel Loayza). [less ▲]

INVESTIGATING T CELLS IN THE CONTEXT OF NEUROIMMUNOLOGY: MOLECULAR AND CELLULAR MECHANISMS DURING A STRESS RESPONSE AND A PATIENT-BASED STUDY IN PARKINSON'S DISEASE

Doctoral thesis (2021)

For a long time, the nervous system and the immune system have been studied as isolated entities, but a growing body of evidence shows that there is an extensive crosstalk between both systems. In fact ... [more ▼]

For a long time, the nervous system and the immune system have been studied as isolated entities, but a growing body of evidence shows that there is an extensive crosstalk between both systems. In fact, neurons and immune cells share certain functional features and reside in close proximity within the tissues, enabling them to effectively communicate. T cells are crucial for mounting and controlling almost any kind of immune response. However, when dysregulated, T cells fail to protect the host from invading pathogens or can cause damage to surrounding tissues, leading to autoimmunity-related pathology. In the first part of this cumulative thesis, we aimed at identifying novel genes regulating CD4 T cell responses and identified VIMP, one of the 25 human proteins containing the 21st amino acid selenocysteine, as a gene having anti-inflammatory functions. Furthermore, T cells express various neurotransmitter receptors allowing the integration of neuronal signal for an appropriate response. In the second part, we showed a CD4-T-cell-intrinsic mechanism through which stress hormones mediate their control over the immune system. We identified a previously unrecognized pathway regulating CD4 T cell differentiation that involves the circadian clock gene Per1 and mTORC1 signalling. Finaly, T cells involvement in different neuropathologies has been reported in the past few decades. Emerging evidence indicates the involvement of the immune system and in particular T cells in the pathogenesis of Parkinson’s disease (PD), the 2nd most common neurodegenerative disease. In the 3rd part of the thesis we systematically characterized the immunological status of early-to-mid stage PD patients and matched healthy controls, and identified a distinct peripheral immunological fingerprint in PD patients, especially in the CD8 T-cell compartment. The findings of the studies described in this cumulative thesis advance our understanding of the regulatory nodes of CD4 T cells during a stress response and fill the knowledge gap on the early involvement of CD8 T cells and other immune subsets in neurodegenerative diseases in the case of PD. [less ▲]

Leveraging High-Frequency Components for Deepfake Detection

in IEEE Workshop on Multimedia Signal Processing (2021)

In the past years, RGB-based deepfake detection has shown notable progress thanks to the development of effective deep neural networks. However, the performance of deepfake detectors remains primarily ... [more ▼]

In the past years, RGB-based deepfake detection has shown notable progress thanks to the development of effective deep neural networks. However, the performance of deepfake detectors remains primarily dependent on the quality of the forged content and the level of artifacts introduced by the forgery method. To detect these artifacts, it is often necessary to separate and analyze the frequency components of an image. In this context, we propose to utilize the high-frequency components of color images by introducing an end-to-end trainable module that (a) extracts features from high-frequency components and (b) fuses them with the features of the RGB input. The module not only exploits the high-frequency anomalies present in manipulated images but also can be used with most RGB-based deepfake detectors. Experimental results show that the proposed approach boosts the performance of state-of-the-art networks, such as XceptionNet and EfficientNet, on a challenging deepfake dataset. [less ▲]

Peut beaucoup mieux faire:Les stéréotypes de genre dans les manuels de l’enseignement fondamental

Article for general public (2021)