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See detailINTERFACIAL COVALENT CHEMICAL BONDING: TOWARDS THERMOREVERSIBLE ADHESION
Hassouna, Lilia UL

Doctoral thesis (2021)

Many industrial sectors like automotive and aeronautic industries are moving toward the use of multi-material devices and composite materials. Reversible adhesion becomes then increasingly important as it ... [more ▼]

Many industrial sectors like automotive and aeronautic industries are moving toward the use of multi-material devices and composite materials. Reversible adhesion becomes then increasingly important as it allows to structurally join dissimilar materials and keep them together during the material’s useful life, while allowing the easy repair of damaged parts or recycling of raw materials. One way to achieve this property is by thermoreversible covalent bonding based on Diels-Alder and its retro Diels-Alder reaction. This “click” reaction occurs between a diene and a dienophile to form an adduct at a certain temperature, then this adduct can be dissociated on command by simple heating. The investigation of the adduct dissociation via retro Diels-Alder reaction is key in understanding the adhesion reversibility based on these systems. In this work an already formed Diels-Alder adduct is synthesized then grafted on plasma polymer coatings or self assembled monolayers. These two different types of surfaces offer different environments for the molecules. Afterwards, a protocol for reaction monitoring based on TOF-SIMS spectroscopy was developed which allowed the determination of kinetic and thermodynamic parameters of the interfacial reaction on both surfaces. The effect of the adducts environment on the reaction was then elucidated by comparing the obtained values. Investigation of the same reaction in solution using 1H NMR spectroscopy confirmed the observations made on the effect of molecules immobilisation on the reaction. Essentially, the more the molecules are immobilized the lower is the energy barrier and the higher is the entropy contribution. Finally, the feasibility of interfacial adhesion based on this system was explored. [less ▲]

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See detailLe vers claudélien, langage " naturel " ou " insolite " ? : Réflexion et analyse à partir de différentes mises en scène de Partage de midi de Paul Claudel
Deregnoncourt, Marine UL

Conference given outside the academic context (2021)

Dès qu’un metteur en scène entend appréhender le théâtre de Paul Claudel, il se voit immédiatement confronté à un problème de taille : le vers claudélien. En effet, la physionomie sensuelle et baroque des ... [more ▼]

Dès qu’un metteur en scène entend appréhender le théâtre de Paul Claudel, il se voit immédiatement confronté à un problème de taille : le vers claudélien. En effet, la physionomie sensuelle et baroque des œuvres claudéliennes « n’a rien de français ». Paul Claudel se situe véritablement en dehors de cette tradition théâtrale et se méfie d’ailleurs des acteurs français. Fort de ses séjours internationaux en tant qu’ambassadeur, ce dramaturge ne rédige pas comme la plupart des auteurs français. Tout d’abord, nous commencerons notre exposé en tentant de démontrer ce qui précède par des extraits sélectionnés de Partage de midi. Cela va nous conduire ensuite à nous intéresser plus particulièrement à cette pièce. Plus qu’aucune autre, cette œuvre, à forte teneur autobiographique, est caractérisée par l’érotisme. Ysé et Mesa, les deux protagonistes principaux, sont unis par une relation, non seulement, amoureuse, mais aussi, charnelle. En témoigne la scène 2 de l’Acte II de Partage de midi. Nous verrons, in fine, que l’histoire de la tradition des mises en scène de cette « scène d’amour » démontre que certains metteurs en scène vont davantage privilégier un érotisme cérébral et textuel, tandis que d’autres vont plutôt s’axer sur un érotisme physique et corporel, où le toucher entre les partenaires est d’importance. [less ▲]

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See detailChronique de droit des marchés financiers
Conac, Pierre-Henri UL

in Revue des Sociétés (2021)

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See detailShortcuts to Squeezed Thermal States
Dupays, Léonce UL; Chenu, Aurélia UL

in Quantum (2021)

Squeezed state in harmonic systems can be generated through a variety of techniques, including varying the oscillator frequency or using nonlinear two-photon Raman interaction. We focus on these two ... [more ▼]

Squeezed state in harmonic systems can be generated through a variety of techniques, including varying the oscillator frequency or using nonlinear two-photon Raman interaction. We focus on these two techniques to drive an initial thermal state into a final squeezed thermal state with controlled squeezing parameters—amplitude and phase—in arbitrary time. The protocols are designed through reverse engineering for both unitary and open dynamics. Control of the dissipation is achieved using stochastic processes, readily implementable via, e.g., continuous quantum measurements. Importantly, this allows controlling the state entropy and can be used for fast thermalization. The developed protocols are thus suited to generate squeezed thermal states at controlled temperature in arbitrary time. [less ▲]

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See detailOn the Exploration and Exploitation Trade-off in Cooperative Caching-enabled Networks
Bommaraveni, Srikanth; Gautam, Sumit; Vu, Thang Xuan UL et al

in IEEE WCNC 2021 proceeding (2021, April)

Edge-caching is considered as a promising solution to address network congestion and reduce delivery latency in the future by bringing the relevant contents close to users. In this context, the commonly ... [more ▼]

Edge-caching is considered as a promising solution to address network congestion and reduce delivery latency in the future by bringing the relevant contents close to users. In this context, the commonly used notion involves the storage of the most popular contents in the cache, while consequently increasing the cache hit ratio (CHR). In the majority of prior works, the content popularity is assumed to be perfectly known and often a priori. However, in reality, the content popularity has to be explored especially for uncertain contents, such as new entrants and fast varying items. In this paper, we develop a framework to analyze the joint exploration and exploitation trade-off by caching both popular and uncertain contents to enable more efficient content caching. Particularly, we formulate an optimization problem to maximize the trade-off between exploration and exploitation subject to the maximum storage capacity, guaranteed CHR, and back-haul energy budget constraints. Further, we solve the formulated mixed-integer combinatorial problem using branch-and-bound optimizer by relaxing the binary to box constraints. The superiority in performance of the proposed method over the state-of-the-art is demonstrated in terms of the CHR and back-haul energy on a realistic Movie-lens dataset. [less ▲]

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See detailBridging the space systems performance-reliability gap for future deep space resources exploration and exploitation.
Pinto Gouveia, Ines UL; Graczyk, Rafal UL; Volp, Marcus UL

Poster (2021, April)

In building equipment for space exploitation, one has to trade system robustness for the high processing capabilities and low energy consumption. The high performance, low robustness approach, is ... [more ▼]

In building equipment for space exploitation, one has to trade system robustness for the high processing capabilities and low energy consumption. The high performance, low robustness approach, is acceptable, especially in Earths’ vicinity. However, in more demanding (especially high-radiation) environments, attempts had disappointing outcomes. The processing-reliability gap, between highly reliable and highly performant systems, spans 2-3 orders of magnitude. This gap brings hope, that some of this excess processing power can be utilized, in building a combination of hardware and software mechanisms that is capable of increasing robustness and resilience of otherwise susceptible semiconductor devices, while allowing to harness the remaining processing power to build affordable space systems with large degrees of autonomy, rich functionality and high bandwidth. At the CritiX research group, we aim to bridge this performance-reliability gap, by researching the enabling building blocks for constructing more reliable and more secure System-on-Chips. [less ▲]

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See detailInspecting the Mechanism of Quantitative Easing in the Euro Area
Koijen, Ralph; Koulischer, François UL; Benoît, Nguyen et al

in Journal of Financial Economics (2021)

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See detailGeographical Stratification of Green Urban Areas
Picard, Pierre M UL; Tran, Thi Thu Huyen UL

in Journal of Economic Geography (2021)

This article studies the provision of urban green areas in cities where residents have preferences for the size of and access to those areas. At the optimum, the number of urban green spaces is a ... [more ▼]

This article studies the provision of urban green areas in cities where residents have preferences for the size of and access to those areas. At the optimum, the number of urban green spaces is a nonmonotone function of distance to the city center, while the sizes and distances to other urban green areas increase as one moves to the urban fringe. This article empirically investigates those properties for the 300 largest European cities by using the Global Monitoring Environment Services Urban Atlas database (European Environmental Agency). The empirical analysis confirms the nonmonotone relationship between the number of urban green spaces and the distance to the city center. The distance between two parks also increases as one moves toward the urban fringe. [less ▲]

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See detailCanonical representations of fingers and dots trigger an automatic activation of number semantics: an EEG study on 10-year-old children
Marlair, Cathy; Lochy, Aliette UL; Buyle, Margot et al

in Neuropsychologia (2021)

Over the course of development, children must learn to map a non-symbolic representation of magnitude to a more precise symbolic system. There is solid evidence that finger and dot representations can ... [more ▼]

Over the course of development, children must learn to map a non-symbolic representation of magnitude to a more precise symbolic system. There is solid evidence that finger and dot representations can facilitate or even predict the acquisition of this mapping skill. While several behavioral studies demonstrated that canonical representations of fingers and dots automatically activate number semantics, no study so far has investigated their cerebral basis. To examine these questions, 10-year-old children were presented a behavioral naming task and a Fast Periodic Visual Stimulation EEG paradigm. In the behavioral task, children had to name as fast and as accurately as possible the numbers of dots and fingers presented in canonical and non-canonical configurations. In the EEG experiment, one category of stimuli (e.g., canonical representation of fingers or dots) was periodically inserted (1/5) in streams of another category (e.g., non-canonical representation of fingers or dots) presented at a fast rate (4 Hz). Results demonstrated an automatic access to number semantics and bilateral categorical responses at 4 Hz/5 for canonical representations of fingers and dots. Some differences between finger and dot configuration’s processing were nevertheless observed and are discussed in light of an effortful-automatic continuum hypothesis. [less ▲]

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See detailTowards the assessment of realistic hybrid precoding in millimeter wave MIMO systems with hardware impairments
Papazafeiropoulos, Anastasios K; Papageorgiou, Georgios K; Kolawole, Oluwatayo Y et al

in IET Communications (2021), 15(12), 1606-1619

Hybrid processing in millimeter wave (mmWave) communication has been proposed as a solution to reduce the cost and energy consumption by reducing the number of radio-frequency (RF) chains. However, the ... [more ▼]

Hybrid processing in millimeter wave (mmWave) communication has been proposed as a solution to reduce the cost and energy consumption by reducing the number of radio-frequency (RF) chains. However, the impact of the inevitable residual transceiver hardware impairments (RTHIs), including the residual additive transceiver hardware impairments (RATHIs) and the amplified thermal noise (ATN), has not been sufficiently studied in mmWave hybrid processing. In this work, the hybrid precoder and combiner are designed, which include both digital and analog processing by taking into account the RATHIs and the ATN. In particular, a thorough study is provided to shed light on the degradation of the spectral efficiency (SE) of the practical system. The outcomes show the steady degradation of the performance by the ATN across all SNR values, which becomes increasingly critical for higher values of its variance. Furthermore, it is shown that RATHIs result in degradation of the system only in the high SNR regime. Hence, their impact in mmWave system operating at low SNRs might be negligible. Moreover, an increase concerning the number of streams differentiates the impact between the transmit and receive RATHIs with the latter having a more severe effect. [less ▲]

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See detailOn the Secrecy Performance of NOMA-Based Integrated Satellite Multiple-Terrestrial Relay Networks With Hardware Impairments
Guo, Kefeng; An, Kang; Zhou, Feng et al

in IEEE Transactions on Vehicular Technology (2021), 70

Integrated satellite terrestrial networks and non-orthogonal multiple access (NOMA) have been confirmed to be promising and effective approaches to achieve substantial performance gains for future ... [more ▼]

Integrated satellite terrestrial networks and non-orthogonal multiple access (NOMA) have been confirmed to be promising and effective approaches to achieve substantial performance gains for future wireless paradigms. This paper studies the effect of hardware impairments (HIs) on the secrecy performance of NOMA-based integrated satellite multiple-terrestrial relay networks (ISMTRNs). Particularly, we consider two important wiretapping cases: Case I, colluding case: all eavesdroppers cooperatively overhear the information; and Case II, non-colluding case: one eavesdropper with the best wiretapping quality is chosen to overhear the main channel information. Specially, the closed-form expressions for the secrecy outage probability (SOP) of the considered NOMA-based ISMTRNs in the presence of the above two eavesdropping cases and partial relay selection scheme are obtained. To obtain further insights in high signal-to-noise ratios (SNRs) regime, the asymptotic analysis of SOP with two considered cases are also derived, which give efficient means to evaluate the benefit of NOMA scheme and the impacts of HIs on the SOP. Moreover, we obtain Monte Carlo (MC) simulations for the secrecy energy efficiency (SEE). [less ▲]

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See detailUniversal Hall conductance scaling in non-Hermitian Chern insulators
Groenendijk, Solofo; Schmidt, Thomas UL; Meng, Tobias

in Physical Review Research (2021)

We investigate the Hall conductance of a two-dimensional Chern insulator coupled to an environment causing gain and loss. Introducing a biorthogonal linear response theory, we show that sufficiently ... [more ▼]

We investigate the Hall conductance of a two-dimensional Chern insulator coupled to an environment causing gain and loss. Introducing a biorthogonal linear response theory, we show that sufficiently strong gain and loss lead to a characteristic nonanalytical contribution to the Hall conductance. Near its onset, this contribution exhibits a universal power law with a power 3/2 as a function of Dirac mass, chemical potential, and gain strength. Our results pave the way for the study of non-Hermitian topology in fermionic transport experiments. [less ▲]

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See detailGP2: The Global Parkinson's Genetics Program
Krüger, Rejko UL; The Global Parkinson's Genetics Program, ; The Global Parkinson's Genetics Program,

in Movement Disorders (2021), 36(4), 842-851

To facilitate the rapid expansion of our understanding of the genetic architecture of PD, both in terms of the depth and global context of this knowledge, we have created the Global Parkinson's Genetics ... [more ▼]

To facilitate the rapid expansion of our understanding of the genetic architecture of PD, both in terms of the depth and global context of this knowledge, we have created the Global Parkinson's Genetics Program (GP2; www.gp2.org). GP2 is the first supported resource project of the Aligning Science Across Parkinson's (ASAP) initiative, an audacious effort supporting PD research.9 GP2 is geared toward creating a worldwide collaborative effort that will first dramatically accelerate the identification of genetic contributors to disease and second establish a network of researchers who can best leverage this understanding to research, diagnose, and treat PD worldwide. Here we describe our mission, the path we have proposed to achieve this, and the core principles of data democratization, transparency, and diversity. [less ▲]

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See detailLA KORA A LA CONFLUENCE DES CULTURES : UNE ETUDE DE LA TRANSMISSION D’UN OBJET CULTUREL DANS UN CONTEXTE TRANSCULTUREL CONTEMPORAIN
Ayegnon, Armel Benvide Osée UL

Doctoral thesis (2021)

The kora is a musical instrument of West African origin. Now played by several individuals who do not necessarily come from her native background, it has been transmitted from her endogenous cultural ... [more ▼]

The kora is a musical instrument of West African origin. Now played by several individuals who do not necessarily come from her native background, it has been transmitted from her endogenous cultural circle to other exogenous circles. We ourselves are kora players and belong to this exogenous circle. In our artistic journey and in our personal history, we have felt the need to produce a hybrid game. Thus, as an artist and researcher, our first objective of a doctoral thesis was to research hybridization processes from a so-called "traditional" repertoire and another called "modern". . Our academic career made us question these categorical qualifiers: "traditional", "modern". This questioning took place through the observation of the process of transmission of the kora. It was made from the very history of the instrument which cannot be dissociated from the history of the individuals and communities who adopted it. However, given the great diversity of the stories, it was necessary to think about setting up tools for collecting knowledge related to contexts and material and immaterial objects, relating to the kora. In order to achieve the primary goal we were pursuing, we finally directed this research towards proposing a method of approach to the study of transmission. There is therefore a dialectic between the object approached and the approach used in this research work. It is this dialectic that corresponds to the main objective of this work. Thus, this doctoral thesis aims to answer the following question: "How to think about the transmission of the kora" object-witness "of the meeting of cultures? "It is a double research focusing both on the transmission of the kora and on the means to study and realize this transmission. This research subsequently led to an applied anthropology and even cultural engineering project. This present writing is the summary of an academic adventure between practice and theory. [less ▲]

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See detailETHICAL PERSPECTIVES ON BIG DATA IN AGRI-FOOD: OWNERSHIP AND GOVERNANCE FOR SAFETY
Sapienza, Salvatore UL

Doctoral thesis (2021)

Big data are reshaping the way we interact with technology, thus fostering new applications to increase the safety-assessment of foods, a critical goal in the protec- tion of individuals’ right to health ... [more ▼]

Big data are reshaping the way we interact with technology, thus fostering new applications to increase the safety-assessment of foods, a critical goal in the protec- tion of individuals’ right to health and the flourishing of the food and feed market. An extraordinary amount of information, including real-time data available from multiple sources, is analysed using machine learning approaches aimed at detecting the existence or predicting the likelihood of future risks, thus reducing the inaccu- racy of risk assessment. Food business operators have to share the results of these analyses when applying to place on the market certain products, whereas agri-food safety agencies (including the European Food Safety Authority) are exploring new avenues to increase the accuracy of their evaluations by processing Big data. Such an informational endowment brings with it opportunities and risks correlated to the extraction of meaningful inferences from data. However, conflicting interests and tensions among the involved entities - the industry, food safety agencies, and con- sumers - hinder the finding of shared methods to steer the processing of Big data in a sound, transparent and trustworthy way. Taken together, a recent reform in the EU sectoral legislation, the lack of trust in the EU food safety system proved by the recent Fitness Check of the General Food Law Regulation and the presence of a considerable number of stakeholders highlight the need of ethical contributions aimed at steering the development and the deployment of Big data applications. At the same time, general Artificial Intelligence guidelines and charters published by European Union institutions and Member States have to be discussed in light of applied contexts, including the one at stake. This thesis aims to contribute to these goals by discussing what principles should be put forward when processing Big data in the context of agri-food safety-risk assessment. The research focuses on two narrow and interviewed topics - data ownership and data governance - by evaluating how the regulatory framework addresses the challenges raised by Big data analysis in these domains. To do so, it adopts a cross-disciplinary research methodology that keeps into account both the technological advances and the policy tools adopted in the European Union, while assuming an ethical perspective when exploring poten- tial solutions. The outcome of the project is a tentative Roadmap aimed to identify the principles to be observed when processing Big data in this domain and their possible implementations. [less ▲]

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See detailModern Slavery and Organizational Research: Digital Technologies as Field Configuring Events
Fletcher, Denise Elaine UL

Presentation (2021, March 26)

In this talk, I give an overview of how the topic of modern slavery is represented in the organization and management literature and I outline a research study which focuses on how entrepreneurial ... [more ▼]

In this talk, I give an overview of how the topic of modern slavery is represented in the organization and management literature and I outline a research study which focuses on how entrepreneurial technological solutions are increasingly being developed to address problems of modern slavery and unfree labour [less ▲]

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See detailReconfigurable Intelligent Surface Optimal Placement in Millimeter-Wave Networks
Ntontin, Konstantinos UL; Boulogeorgos, Alexandros-Apostolos A.; Selimis, Dimitrios et al

in IEEE Open Journal of the Communications Society (2021), 2

This work discusses the optimal reconfigurable intelligent surface placement in highly-directional millimeter wave links. In particular, we present a novel system model that takes into account the ... [more ▼]

This work discusses the optimal reconfigurable intelligent surface placement in highly-directional millimeter wave links. In particular, we present a novel system model that takes into account the relationship between the transmission beam footprint at the RIS plane and the RIS size. Subsequently, based on the model we derive the end-to-end expression of the received signal power and, furthermore, provide approximate closed-form expressions in the case that the RIS size is either much smaller or at least equal to the transmission beam footprint. Moreover, building upon the expressions, we derive the optimal RIS placement that maximizes the end-to-end signal-to-noise ratio. Finally, we substantiate the analytical findings by means of simulations, which reveal important trends regarding the optimal RIS placement according to the system parameters. [less ▲]

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See detailWhat Blanchard gets wrong: The puzzling persistence of managerialism in EU fiscal governance
Dani, Marco; Guarascio, Dario; Mendes, Joana UL et al

Diverse speeches and writings (2021)

The Covid-19 pandemic has prompted renewed debate over the architecture of Europe’s Economic and Monetary Union. In a recent blog post, "What Blanchard gets wrong: The puzzling persistence of ... [more ▼]

The Covid-19 pandemic has prompted renewed debate over the architecture of Europe’s Economic and Monetary Union. In a recent blog post, "What Blanchard gets wrong: The puzzling persistence of managerialism in EU fiscal governance", Marco Dani, Dario Guarascio, Joana Mendes, Agustin José Menéndez, Harm Schepel and Mike Wilkinson respond to a recent proposal to overhaul the EU’s current fiscal framework. They argue that while the EU’s fiscal rules should undoubtedly be reformed, a more radical solution is required that puts democratic politics at the heart of the EU’s fiscal governance. [less ▲]

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