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See detailExperimental evaluation of RF waveform designs for Wireless Power Transfer using Software Defined Radio
Gautam, Sumit UL; Kumar, Sumit UL; Chatzinotas, Symeon UL et al

in IEEE Access (2021), 9

The possibility to harvest energy from ambient radio-frequency (RF) sources has intrigued humankind for the past several decades. In this context, there has been a tremendously growing research interest ... [more ▼]

The possibility to harvest energy from ambient radio-frequency (RF) sources has intrigued humankind for the past several decades. In this context, there has been a tremendously growing research interest in the field of wireless power transfer (WPT) using the RF range of the electromagnetic (EM) spectrum. In this paper, we experimentally investigate the aspect of real-time energy harvesting (EH) via different types of waveform designs such as orthogonal frequency division multiplexing (OFDM), square, triangular, sinusoidal, and sawtooth. We make use of a Software Defined Radio (SDR) and a Powercast P21XXCSR-EVB EH module to carry out the experiments on a practical device to assess performance. Specifically, we are interested in obtaining some insights based on the comparison between the aforementioned waveform designs from the perspectives of the separation distance between the USRP and P21XXCSR-EVB EH module, and power emission via USRP. In this vein, we perform additional subsequent experiments after reporting the practical effectiveness of the OFDM waveform, which also follows our intuitive analysis. Correspondingly, we study the effect on WPT with variable USRP transmit power, the separation distance between the USRP and EH antennas, number of OFDM sub-carriers, and multipath setting. As an application of OFDM, the effectiveness of fifth generation-new radio (5G-NR) and long-term evolution (LTE) waveforms are also tested for the WPT mechanism. The demonstration of the EH is provided in terms of the above-mentioned investigation metrics while seeking the best waveform to support WPT. [less ▲]

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See detailIntertwining distant reading of web archives and oral histories of the COVID crisis
Schafer, Valerie UL

Scientific Conference (2021, September 22)

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See detailGene-by-environment modulation of lifespan and weight gain in the murine BXD family
Roy, Suheeta; Bou Sleiman, Maroun; Jha, Pooja et al

in Nature Metabolism (2021)

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See detailThe Experience of Security in Human-Computer Interactions: Understanding Security Perceptions Through the Concept of User Experience
Distler, Verena UL

Doctoral thesis (2021)

In traditional interactions that do not rely on technology, most people are able to assess risks to their privacy and security and understand how to mitigate these risks. However, risk assessment and ... [more ▼]

In traditional interactions that do not rely on technology, most people are able to assess risks to their privacy and security and understand how to mitigate these risks. However, risk assessment and mitigation is more challenging when interacting with technology, and people’s perceptions of security and privacy risks are not always aligned with reality. It is important for those who design technologies to understand how people perceive the security of technologies in order to avoid having their designs contribute to erroneous perceptions. Instead, interactions with technology should be deliberately designed to ensure that people do not over- or underestimate the security provided by the system. This dissertation contributes to a better understanding of users’ perceptions of security in human-computer interactions. It investigates which factors induce a perception of security and privacy risks and how user-centered design can influence these factors to deliberately design for or against perceived security. I use a mixed-methods approach to address these objectives, including a systematic literature review, empirical data collection with focus groups, expert co-creation sessions, user tests in a controlled environment and a quantitative survey experiment. The first research objective is to analyze how security and privacy researchers induce a perception of security and privacy risks with research participants. We conducted a systematic literature review and focused our analysis on study methods; risk representation; the use of prototypes, scenarios, and educational interventions; the use of deception to simulate risk; and types of participants. We discuss benefits and shortcomings of the methods, and identify key methodological, ethical, and research challenges when representing and assessing security and privacy risk. We also provide guidelines for the reporting of user studies in security and privacy. The second research objective is to explore the factors that contribute to the acceptance of privacy and security risks in situations where people need to weigh the potential advantages of a technology against its associated privacy or security risks. We conducted a series of focus groups and highlighted the reasons why people accept compromises to their privacy and security, finding that perceived usefulness and the fulfilment of the psychological needs for autonomy and control were important factors. Our results suggest potential links between technology acceptance models and user experience models in the context of privacy-relevant interactions. The third research objective is to design and evaluate examples of visible representations of security mechanisms, with a focus on encryption. We studied the effects of these visual and textual representations empirically to understand the impact of these visible security mechanisms on user experience, perceptions of security and users’ understanding of encryption. We addressed this question in a series of studies, both lab studies and online experiments. In a vignette experiment, we find that more complex descriptions of encryption can lead to a better understanding and higher perceived security when designed carefully. However, we find no effect of novel visualizations of encryption on user experience (UX), perceived security or understanding of encryption. The fourth objective is to explore how we might make the link from subjective experience to more secure behaviors. We introduce a new framework of security-enhancing friction design. The framework suggests helping users behave more securely by designing for moments of negative UX in security-critical situations while also ensuring that overall UX remains at an acceptable level to avoid disuse of secure technologies. Overall, this doctoral dissertation contributes to research in the field of human-computer interaction, and more specifically, usable privacy and security. It improves our understanding of the methods used by researchers in the field of usable privacy and security use to create a perception of risk, and the factors that make people accept or reject certain privacy trade-offs. This dissertation also makes contributions to helping researchers and creators of technology understand how their designs influence perceptions of security, UX and understanding of encryption. This enables them to design for or against a perception of security, depending on the actual level of security provided by the technology. Finally, we conceptualize security-enhancing friction, a framework that suggests helping users to behave more securely by designing for moments of negative UX. [less ▲]

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See detailTaking the Complex Dynamics of Human–Environment–Technology Systems Seriously: A Case Study in Doctoral Education at the University of Luxembourg
König, Ariane UL; Ravetz, Jerome; Raber, Bo Manuel UL et al

in Frontiers in Sustainability (2021), 2

Our existential sustainability challenges involve human–environment–technology systems that are complex, dynamic and tightly coupled. But at universities, knowledge, in teaching and research, is mostly ... [more ▼]

Our existential sustainability challenges involve human–environment–technology systems that are complex, dynamic and tightly coupled. But at universities, knowledge, in teaching and research, is mostly organized into discrete parcels, the disciplines. These are further divided into the categories of natural sciences, social science and the humanities. This paper addresses the question of how in their training of researchers, universities can equip them to better understand their roles and also to act as change agents. It describes a doctoral school course in transferable skills that is offered across faculties. The unique aim of the course is to provide a space for reflection on different research paradigms and the way they differ in their framing the role of a scientific researcher in pluralist societies that face existential challenges. The course introduces diverse more recent approaches to scientific inquiry that harness the potential of democratizing science in our networked knowledge society, including critical interdisciplinarity, post-normal science, citizen science and transformative sustainability science, that complement normal disciplinary research practices. [less ▲]

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See detailLe décrochage scolaire. Un processus de constructions et de déconstructions
Weber, Jean-Marie UL; Voynova, Ruzhena

Book published by Champ social - Champ Social Editions (2021)

Les causes du décrochage scolaire sont multiples et ont été analysées par différentes disciplines comme la sociologie, la psychologie sociale, les sciences cognitives ou la pédagogie spéciale. Le projet ... [more ▼]

Les causes du décrochage scolaire sont multiples et ont été analysées par différentes disciplines comme la sociologie, la psychologie sociale, les sciences cognitives ou la pédagogie spéciale. Le projet de recherche présenté dans cet ouvrage est de type psychanalytique. Il vise à approcher le décrochage comme un symptôme, donc comme un compromis entre conscience et inconscience, aliénation et séparation, désir d’apprendre et craintes ou inhibitions. Les différents concepts : rapport au savoir, répétition du ratage, pulsion de mort, jouissance et acting out, ont constitué des outils pour analyser à travers des récits d’épisodes de vie de jeunes décrocheurs et d’enseignants le symptôme et l’acte du décrochage ainsi que les transformations qui s’installent ou non auprès de ces jeunes sujets en difficultés. [less ▲]

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See detailLe décrochage scolaire. Un processus de constructions et de déconstructions
Weber, Jean-Marie UL; Voynova, Ruzhena

Book published by Champ social - Champ Social Editions (2021)

Les causes du décrochage scolaire sont multiples et ont été analysées par différentes disciplines comme la sociologie, la psychologie sociale, les sciences cognitives ou la pédagogie spéciale. Le projet ... [more ▼]

Les causes du décrochage scolaire sont multiples et ont été analysées par différentes disciplines comme la sociologie, la psychologie sociale, les sciences cognitives ou la pédagogie spéciale. Le projet de recherche présenté dans cet ouvrage est de type psychanalytique. Il vise à approcher le décrochage comme un symptôme, donc comme un compromis entre conscience et inconscience, aliénation et séparation, désir d’apprendre et craintes ou inhibitions. Les différents concepts : rapport au savoir, répétition du ratage, pulsion de mort, jouissance et acting out, ont constitué des outils pour analyser à travers des récits d’épisodes de vie de jeunes décrocheurs et d’enseignants le symptôme et l’acte du décrochage ainsi que les transformations qui s’installent ou non auprès de ces jeunes sujets en difficultés. [less ▲]

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See detailCommunication Algorithms for 5G Internet of Things Systems via Satellites
Kodheli, Oltjon UL

Doctoral thesis (2021)

Detailed reference viewed: 27 (10 UL)
See detailExploring the History of Digital History
Zaagsma, Gerben UL

Scientific Conference (2021, September 20)

As long as new preservation technologies and computing machines have been developed, the question of their utility and uptake in historical research practices has been debated. Yet, the very fact that ... [more ▼]

As long as new preservation technologies and computing machines have been developed, the question of their utility and uptake in historical research practices has been debated. Yet, the very fact that historical knowledge production has always been affected by new and emerging technologies is often forgotten. Similarly, the fact that key epistemological and methodological questions in what we now call ‘digital history’ were already debated decades ago by earlier generations of computing historians (analog and digital) is often overlooked. There is a lack of transmission of accumulated knowledge from the past and it sometimes seems as if every new generation of historians rediscovers the promise of ‘digital history’, with all of its attending hopes, visions and ambitions for reinventing and reshaping historical research. To fill this gap, this paper will explore what a history of digital history might look like. It will do so by focusing on hybridity as a key characteristic of historical research. Hybridity, seen as some form of integrating newly emerging tools, technologies, materials, and/or practices in historical research, has a long history that predates the advent of computers. In my paper I will map and qualify that history according to the main phases of historical research. The paper will conclude by outlining what groundwork is necessary to explore digital history’s forgotten roots: a basic overview of the field’s different spatio-temporal and ideological trajectories and recreation of the networks of computing historians in the pre-PC and early PC period. [less ▲]

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See detailMachine learning in mix design of Miscanthus lightweight concrete
Pereira Dias, Patrick; Jayasinghe, Laddu Bhagya; Waldmann, Daniele UL

in Construction and Building Materials (2021)

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See detailBinary blended cement pastes and concrete using gravel wash mud (GWM) powders
Thapa, Vishojit; Waldmann, Daniele UL

in Construction and Building Materials (2021)

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See detailNonlinear three-dimensional anisotropic material model for failure analysis of timber
Eslami, Hooman; Jayasinghe, Laddu Bhagya; Waldmann, Daniele UL

in Engineering Failure Analysis (2021)

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See detailRéflexions sur la signification historique du 11 septembre 2001
Scuto, Denis UL

Article for general public (2021)

The Tageblatt today reproduces for the 20th anniversary of 9/11 excerpts from an article published by the historian Denis Scuto almost twenty years ago in the same Luxembourg newspaper Tageblatt, on 13 ... [more ▼]

The Tageblatt today reproduces for the 20th anniversary of 9/11 excerpts from an article published by the historian Denis Scuto almost twenty years ago in the same Luxembourg newspaper Tageblatt, on 13 December 2001, on the historical meaning of the attacks of 11 September 2001. Three months after the attacks, Denis Scuto explained the changes, imagined or real, and the hopes, legitimate but quickly disappointed. [less ▲]

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See detailReview of Adam Crymble: Technology and the Historian. Transformations in the Digital Age
Zaagsma, Gerben UL

in H-Soz-Kult: Kommunikation und Fachinformation für die Geschichtswissenschaften (2021)

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See detailOn the Maintenance of System User Interactive Tests
Rwemalika, Renaud UL

Doctoral thesis (2021)

Many companies rely on software testing to verify that their software products meet their requirements. As such, software testing is a keystone of the quality process. It offers means to assess that both ... [more ▼]

Many companies rely on software testing to verify that their software products meet their requirements. As such, software testing is a keystone of the quality process. It offers means to assess that both functional and technical requirements are met. However, scaling the number of tests while preserving their quality poses challenges, just as in any software artifact. This is particularly true in the case of complex tests interacting with the SUT through its Graphical User Interface (GUI), i.e. System User Interactive Test (SUIT). The problem becomes challenging because as the System Under Test (SUT) evolves, the SUIT suites need to adapt and conform to the evolved software. Indeed, because the user interface is a part of the system that tends to undergo rapid evolutions, SUITs are particularly prompt to break. As the first contribution of this dissertation, we aim to demonstrate the problem of test maintenance and overall improve the understanding of SUIT scripts evolution. To that end, we identify, collect and analyze test code changes across the evolution of an industrial test suite. We show that the problem of test maintenance is largely due to test fragility (most commonly performed changes are due to locator and synchronization issues) and bad practices (over 30% of keywords are duplicated). To further investigate the question of bad test code practices such as test clones, we perform a multivocal study to identify which bad practices, i.e. SUIT smells, are already studied in both industry and academia. This process yields a catalog of 35 test code smells. For 16 of them, we derive metrics to analyze their diffusion across tests as well as potential refactoring actions removing the test code smells. Through an empirical study including both industrial and open-source test suites, we show that test code smells are largely present in SUITs, potentially contributing to SUIT fragility and hindering the maintenance process. Interestingly, refactoring actions remain rare during the lifespan of the tests. Yet, symptoms tend to disappear as old tests are discarded and new ones are introduced. However, during the analysis of SUIT smells, we observe that bad practices impacting locators do not appear often in the test code. This observation contrasts with the analysis of the evolution of the SUIT presented in our first empirical study. This apparent contradiction arises from the limitation of property-based locators which rely on the structure of the representation layer of the SUT. Indeed, such approaches are sensitive to internal iso-functional changes occurring during the normal evolution of the SUT. To account for this limitation, we introduce a new way of expressing locators, HPath. Instead of relying on the internal representation of the presentation layer, HPath relies on the rendered characteristics of the GUI. Our results suggest that despite what is presented in the literature on locators, expressions relying on a smaller number of GUI elements to fully qualify a target do not necessarily lead to more robust locators. On the contrary, the choice of the GUI element properties seems to play a stronger role in the robustness to change. Overall, this dissertation provides insights into how SUITs evolve and shows that SUIT fragility plays a major role in the associated maintenance effort. It also proposes techniques that effectively facilitate SUIT maintenance with the early detection of sub-optimal patterns and the introduction of a locator representation more robust to SUT evolution. [less ▲]

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See detailFacets of conscientiousness and their relation to academic achievement: a person-centered approach
Franzen, Patrick UL; Niepel, Christoph UL; Arens, A Katrin et al

Scientific Conference (2021, September 16)

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See detailWeb Archives of the COVID Crisis: Digital Voices, Preservation and Loss
Schafer, Valerie UL

Presentation (2021, September 16)

This roundtable, which is organized by the WARCnet network and chaired by Valérie Schafer (C2DH, University of Luxembourg), aims to shed light on the issues, challenges, values and limits of web archiving ... [more ▼]

This roundtable, which is organized by the WARCnet network and chaired by Valérie Schafer (C2DH, University of Luxembourg), aims to shed light on the issues, challenges, values and limits of web archiving during the COVID crisis. It will combine analysis by web archivists and scholars and entwine analysis of web archiving practices and preserved web content, in order to address several key issues related to the conference, such as the “silences” and “noises” of these archives. The first part of the roundtable will focus on web archives collections that have been created during the COVID-19 crisis by many institutions throughout Europe. Friedel Geeraert (The State Archives of Belgium and the Royal Library of Belgium) will provide a short comparative overview of the strategies of web archiving institutions in Europe, that the team documented through an oral history campaign, while Nicola Bingham (The British Library, UK) will offer more precise overviews of the collections that were gathered respectively by the UK Web Archive and the IIPC (International Internet Preservation Consortium). Claude Mussou (Ina THEQUE, France) will explore the archiving of Twitter at the Institut national de l’audiovisuel (France). Niels Brügger (Aarhus University, Denmark) and Jane Winters (SAS, University of London) will then discuss memories and heritage of the COVID-crisis through the lens of these web archives. Finally the last part will focus on research approaches, notably close and distant reading, and the collective and individual traces, social and political expressions at stake in these web archives: Valérie Schafer will comment on the distant reading approach within these archives. Sophie Gebeil (Aix-Marseille University, France) will underline issues related to “carers” and social struggles. Valérie Schafer will also briefly mention the gendered approach of the COVID crisis that the working group is currently conducting. This roundtable will be followed by a discussion with the audience in order to deepen the topics that are at the core of the conference, whether it be loss, preservation, the political “we”, feelings, etc. [less ▲]

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See detailAttaques et preuves de sécurité des protocoles d'échange de clés authentifiés
Sala, Petra UL

Doctoral thesis (2021)

The vast majority of communication on the Internet and private networks heavily relies on Public-key infrastructure (PKI). One possible solution, to avoid complexities around PKI, is to use Password ... [more ▼]

The vast majority of communication on the Internet and private networks heavily relies on Public-key infrastructure (PKI). One possible solution, to avoid complexities around PKI, is to use Password Authenticated Key-Exchange (PAKE) protocols. PAKE protocols enable a secure communication link between the two parties who only share a low-entropy secret (password). PAKEs were introduced in the 1990s, and with the introduction of the first security models and security proofs in the early 2000s, it was clear that PAKEs have a potential for wide deployment - filling the gap where PKI falls short. PAKEs' PKI-free nature, resistance to phishing attacks and forward secrecy are just some of the properties that make them interesting and important to study. This dissertation includes three works on various aspects of PAKEs: an attack on an existing PAKE proposal, an application of PAKEs in login (for password leak detection) and authentication protocols (HoneyPAKEs), and a security analysis of the J-PAKE protocol, that is used in practice, and its variants. In our first work, we provide an empirical analysis of the zkPAKE protocol proposed in 2015. Our findings show that zkPAKE is not safe against offline dictionary attacks, which is one of the basic security requirements of the PAKE protocols. Further, we demonstrate an implementation of an efficient offline dictionary attack, which emphasizes that, it is necessary to provide a rigorous security proof when proposing a new protocol. In our second contribution, we propose a combined security mechanism called HoneyPAKE. The HoneyPAKE construction aims to detect the loss of password files and ensures that PAKE intrinsically protects that password. This makes the PAKE part of the HoneyPAKE more resilient to server-compromise and pre-computation attacks which are a serious security threat in a client-server communication. Our third contribution facilitates the wider adoption of PAKEs. In this work, we revisit J-PAKE and simplify it by removing a non-interactive zero knowledge proof from the last round of the protocol and derive a lighter and more efficient version called sJ-PAKE. Furthermore, we prove sJ-PAKE secure in the indistinguishability game-based model, the so-called Real-or-Random, also satisfying the notion of perfect forward secrecy. [less ▲]

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See detailVerification of design models of cyber-physical systems specified in Simulink
Gaaloul, Khouloud UL

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 ▲]

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