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See detailDeformation Based Curved Shape Representation
Demisse, Girum UL

Doctoral thesis (2017)

Representation and modelling of an objects' shape is critical in object recognition, synthesis, tracking and many other applications in computer vision. As a result, there is a wide range of approaches in ... [more ▼]

Representation and modelling of an objects' shape is critical in object recognition, synthesis, tracking and many other applications in computer vision. As a result, there is a wide range of approaches in formulating representation space and quantifying the notion of similarity between shapes. A similarity metric between shapes is a basic building block in modelling shape categories, optimizing shape valued functionals, and designing a classifier. Consequently, any subsequent shape based computation is fundamentally dependent on the computational efficiency, robustness, and invariance to shape preserving transformations of the defined similarity metric. In this thesis, we propose a novel finite dimensional shape representation framework that leads to a computationally efficient, closed form solution, and noise tolerant similarity distance function. Several important characteristics of the proposed curved shape representation approach are discussed in relation to earlier works. Subsequently, two different solutions are proposed for optimal parameter estimation of curved shapes. Hence, providing two possible solutions for the point correspondence estimation problem between two curved shapes. Later in the thesis, we show that several statistical models can readily be adapted to the proposed shape representation framework for object category modelling. The thesis finalizes by exploring potential applications of the proposed curved shape representation in 3D facial surface and facial expression representation and modelling. [less ▲]

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See detailA Model-Based Framework for Legal Policy Simulation and Compliance Checking
Soltana, Ghanem UL

Doctoral thesis (2017)

Information systems implementing requirements from laws and regulations, such as taxes and social benefits, need to be thoroughly verified to demonstrate their compliance. Several Verification and ... [more ▼]

Information systems implementing requirements from laws and regulations, such as taxes and social benefits, need to be thoroughly verified to demonstrate their compliance. Several Verification and Validation (V&V) techniques, such as reliability testing, and modeling and simulation, can be used for assessing that such systems meet their legal. Typically, one has to model the expected (legal) behavior of the system in a form that can be executed (simulated), subject the resulting models and the system to the same input data, and then compare the observed behavior of the model simulation and system execution. Existing V&V techniques often rely on code and complex logical expressions with no intuitive appeal to legal experts for specifying the expected behavior of a given system. Subsequently, one has no practical way to validate with legal experts that the underlying legal requirements are indeed complete and constitute a faithful representation of what needs to be implemented. Further, manually defining the expected behavior of a system and its test oracles is a tedious and error-prone task. The challenge here is to find a suitable knowledge representation that can be understood by all the involved stakeholders, e.g., software engineers and legal experts, but that remains complete and precise enough to enable automated analysis such as simulation and testing. As real data is seldom accessible in highly regulated domains, V&V requires the generation of synthetic testing data that can be used to build confidence in the reliability of the system under test. In particular, such data has to be structurally and logically well-formed to raise meaningful failures that can help reasoning about the reliability of the system under test. Further, the data should exhibit as much as possible the actual or anticipated system usage to help mimic how the system would behave under realistic circumstances. Generating such data is not a trivial task as the underlying data schemas are usually large and subject to numerous complex domain-related logical constraints. In this thesis, we investigate the use of the Unified Modeling Language (UML) and model-driven technologies, e.g., model to code transformations, to facilitate V&V activities for information systems that have to conform to laws and regulations, while tackling the above challenges. All our technical solutions have been developed and empirically evaluated in close collaboration with a government administration. Concretely, the technical solutions covered by this thesis include: - A modeling notation and methodology for formalizing legal policies. We propose a modeling notation and methodology for building abstract interpretations of the law. Models built using our methodology are simple enough to be understood by the involved stakeholders and are, at the same time, detailed enough to enable automated V&V activities. - A model-based simulation framework. We develop a model-based framework and associated tool support for simulating legal policies, when formalized using the aforementioned modeling methodology. Simulation provides a comparison baseline of how a compliant system should behave. Further, simulation is a mean to support decision-making when considering legal changes. Specifically, we report on a sizable case study where we assess the anticipated economic implications of a given policy change in Luxembourg’s tax law. - A model-based generator of test cases for reliability testing. We develop a heuristic approach for generating valid and representative test cases (data). Our generator is scalable and produces high-quality test data that is suitable for testing the reliability of data-intensive systems, e.g., a tax management system. [less ▲]

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See detailManaging the City-Region Like a Startup: Entrepreneurialism and Shifting Local Economic Governance in Developing Countries
Fegue, Jean Cyril UL

Doctoral thesis (2017)

The emerging experience of cities in the Global South regarding the complexity of their response to territorial competition's pressures requires the rethinking of the very concept of urban competitiveness ... [more ▼]

The emerging experience of cities in the Global South regarding the complexity of their response to territorial competition's pressures requires the rethinking of the very concept of urban competitiveness. This study proposes the distributionally-sensitive modeling of urban competitiveness (DS-MUC) in a perspective that is driven by the norm of Equity. The DS-MUC is posited as a critical theory to neoliberalism and as a contribution to the social sustainability and to the normative investigation of post-capitalist urban transformations in the Global South.The application of the DS-MUC in the investigation of Da Nang in Vietnam and Cebu City in the Philippines reveals that an interactive, relational and network-based entrepreneurial governance's capacity has a much greater proclivity to deliver Equity and therefore to achieve a 'high-quality competitiveness' than a city's organizing capacity embedded in illiberal, state-paternalistic and public-sector monopolistic arrangements. [less ▲]

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See detailCorporations and Human Rights: Searching for International Norms for Corporate Conduct in Domestic Case Law
Baglayan Ceyhan, Basak UL

Doctoral thesis (2017)

Recent years have seen much debate concerning the interplay between human rights and corporations. Part of that debate has focused on corporate violations of human rights norms and possible legal ... [more ▼]

Recent years have seen much debate concerning the interplay between human rights and corporations. Part of that debate has focused on corporate violations of human rights norms and possible legal accountability mechanisms for such breaches. The present research is concerned with one such accountability mechanism, namely litigation before domestic courts seeking to enforce corporations’ international obligations and the complaints before the OECD National Contact Points (‘NCPs’). The thesis analyses how domestic courts and the OECD NCPs have conceptualised and implemented corporations’ human rights obligations. It is premised on the assumption that, through their application of international norms in their particular national context, these institutions act to crystallize and clarify the ambit of such norms. [less ▲]

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See detailContextual Integrity and Tie Strength in Online Social Networks: Social Theory, User Study, Ontology, and Validation
Ahmed, Javed UL

Doctoral thesis (2017)

Online Social Networks (OSNs) have become an important part of daily digital interactions for more than half billion users around the world. Unconstrained by physical spaces, OSNs offer to social web ... [more ▼]

Online Social Networks (OSNs) have become an important part of daily digital interactions for more than half billion users around the world. Unconstrained by physical spaces, OSNs offer to social web users new means to communicate, interact, and socialize. Online social networks exhibit many of the characteristics of human societies in terms of forming relationships and sharing personal information. However, current OSNs mainly assume binary, static, and symmetric relationship of equal value between the connected users. In human societies, social relationships are of varying tie strength, dynamic, and asymmetric in nature. The lack of an effective mechanism to represent diversity in social relationships leads to undesirable consequences of users personal information leakage to the unwanted audience and raises privacy concerns. The issue of privacy has received significant attention in both the research literature and the mainstream media. In this dissertation, we conduct a user study to analyze users' attitude towards personal information disclosure in online social networks. The study gives insight into user's information sharing behavior and interaction patterns in online social networks. The findings reveal that personal information disclosure depends on the quality of relationship among the users and it can be easily inferred from user interaction pattern in online social networks. We propose a theoretical framework that addresses the aforementioned issue from a social science perspective and exploits existing social theories of Goffman, Granovetter, and Nissenbaum to model social privacy for OSNs users. Based on this theoretical framework, we developed SOCPRI (SOCial PRIvacy) ontology to represent diversity in social relationships in online social networks. This model regulates personal information disclosure on the basis of the social role and the relationship quality between the OSNs users. The model is evaluated by translating competency questions into description logic (DL) queries to demonstrate the applicability of our approach. The results of ontology evaluation demonstrate the appropriateness of our ontology against proposed requirements. Based on this model a privacy-friendly online social networking environment can be developed to address some of the existing issues such as context collapse and user control. [less ▲]

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See detailModel-Based Specification, Deployment and Adaptation of Robot Perception Systems
Hochgeschwender, Nico UL

Doctoral thesis (2017)

As robots are becoming ubiquitous and more capable, the need for introducing solid robot software development methods is pressing to increase robots' task spectrum. This thesis is concerned with improving ... [more ▼]

As robots are becoming ubiquitous and more capable, the need for introducing solid robot software development methods is pressing to increase robots' task spectrum. This thesis is concerned with improving software engineering of robot perception systems. The presented research employs a model-based approach to provide the means to represent knowledge about robotics software. The thesis is divided into three parts, namely research on the specification, deployment and adaptation of robot perception systems. The first part contributes the design and development of two domain-specific languages, namely RPSL and DepSL. Those languages provide suitable notations and abstractions to enable domain experts to express, compose and explore functional, architectural and deployment design decisions of robot perception systems. The resulting models are interpretable, thus they can be used not only to communicate design decisions to stakeholders, but also to verify them in an early development stage. The second part contributes means for deploying perception systems on real robot systems even in the presence of varying resource conditions. To this end, functional, architectural and deployment models are composed in a graph-structure. Such a graph enables not only humans, but also robots to derive implicitly defined information about their software both at design time and run time. The second part also contributes a reference architecture for deploying robot perception systems. The architecture provides a template solution for integrating not only the models required for deployment, but also all the other means required to carry out deployment. The third part utilizes both RPSL, DepSL and the reference architecture to specify, implement and evaluate three different robot perception systems. Those are capable to satisfy changing requirements induced, for example, by the robot's tasks or environment. This is achieved by proposing algorithms which derive adaptation actions based on models and varying requirements. [less ▲]

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See detailForm und Funktion des Diminutivs im luxemburgisch-moselfränkischen Übergangsgebiet
Edelhoff, Maike UL

Doctoral thesis (2017)

Diminutive formation is a common word formation process of the Luxembourgish (Lux.) lan-guage and the neighbouring Moselle-Franconian (MsFrc) dialects. The aim of this thesis is to collect and to analyse ... [more ▼]

Diminutive formation is a common word formation process of the Luxembourgish (Lux.) lan-guage and the neighbouring Moselle-Franconian (MsFrc) dialects. The aim of this thesis is to collect and to analyse the characteristics of this process, integrate them into common morpho-logical theories and to establish their geolinguistic properties. On a functional level, the diminutives show the same characteristics in both varieties although the loss of the evaluative meaning is further developed in Lux. than in MsFrc. How-ever, the most apparent differences can be seen on the level of the fomal execution of the di-minutive rule: While the diminutives in MsFrc share many similarities, such as grammatical gender, the singular suffix and to an extent also the plural marking with Standard German, the Lux. language differs greatly from the others. In Lux. the singular formation is quite similar to the one in the other varieties, however, the plural suffix is triggered by the syllabic and prosodic properties of the base noun. Additionally, the grammatical gender of the diminutive is in con-cordance with the gender of the base noun and hence, not influenced by the suffix. The reasons for these peculiar attributes are to be found both in the historical development of the language and its current structural form as well as in its sociolinguistic context. The consequences of the differing structural properties are clearly displayed on a geo-linguistic level. Although the varieties are historically closely related the differing formal ex-pressions of the diminutive meaning lead to the emergence of groups of isoglosses coinciding with the state border. In brief, the history and the present situation of the diminutive serve as evidence that the dialect continuum that once crossed the state border has been falling apart and that it has been replaced by a solid linguistic border that separates the closely related varieties from each other. [less ▲]

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See detailAb initio approaches to Resonant Raman Spectroscopy of Transition Metal Dichalcogenides
Pereira Coutada Miranda, Henrique UL

Doctoral thesis (2017)

This thesis deals with the theory and simulation of resonant Raman spectroscopy in two-dimensional transition metal dichalcogenides. We present two different ab initio approaches. In the first, we ... [more ▼]

This thesis deals with the theory and simulation of resonant Raman spectroscopy in two-dimensional transition metal dichalcogenides. We present two different ab initio approaches. In the first, we calculate the Raman susceptibility tensor as a function of laser energy from the change of the dielectric susceptibility with atomic displacements. In the second, we formulate the Raman tensor in terms of time-dependent perturbation theory and calculate it using electron-light and electron-phonon coupling matrix elements obtained from density functional theory. We investigate the role of resonance, quantum interference and excitonic effects in the Raman spectra of single and triple-layer MoTe2. We compare our simulations with experimental results, explaining the dependence of the Raman intensities on the excitation energy. We demonstrate that the two approaches are formally and numerically equivalent in the adiabatic limit. In addition, the second approach allows to include the dynamical effects and captures a shift of the intensities with respect to the adiabatic case. This method is also more computationally efficient and is extended to include temperature effects using many-body perturbation theory. We have implemented both of these methods in a software package with interfaces to open source ab initio codes. Furthermore, we have developed web based tools to visualize excitonic states and phonon modes. [less ▲]

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See detailLe mouvement-liberté. Généalogie philosophique et littéraire d'un imaginaire politique
Jeusette, Julien UL

Doctoral thesis (2017)

Cette thèse, qui se situe au croisement de trois champs de recherche (la littérature, la philosophie, l’histoire des idées), a pour ambition de retracer la manière dont le déracinement, le nomadisme et ... [more ▼]

Cette thèse, qui se situe au croisement de trois champs de recherche (la littérature, la philosophie, l’histoire des idées), a pour ambition de retracer la manière dont le déracinement, le nomadisme et l’errance ont été investis, à un moment donné de notre Histoire, d’une appréciation positive, au moment même où la sédentarité et l’enracinement se sont vus taxés de conservatisme ennuyeux. Nous postulons que cet imaginaire politique, que nous appelons « mouvement-liberté » (tout discours axiologique valorisant le mouvement libre et infini, et dévalorisant toute forme d’immobilité), émerge dans Les Nourritures terrestres d’André Gide et dans Ainsi parlait Zarathoustra de Nietzsche à la fin du XIXe siècle. Nous montrons ensuite que ce discours s’amplifie au cours des années 1920-1930, notamment au sein des textes que nous avons qualifiés de « romans de fuite » ; la troisième partie de la thèse porte sur les années 1960-1970 et met en évidence la redondance discursive du « mouvement-liberté » au sein de la « French theory ». La dernière partie met en lumière la façon dont le « mouvement-liberté », qui était politiquement critique et explicitement de l’ordre du contre-pouvoir de la fin du XIXe siècle jusqu’aux années 1970, est aujourd’hui récupéré par le néolibéralisme, qui le revendique pour son propre compte et le travestit en « idéologie nomade ». [less ▲]

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See detailTESTING 21ST CENTURY SKILLS IN A CHANGING NATURE OF WORK: THE CONSTRUCT VALIDITY OF COMPLEX PROBLEM SOLVING AND ORGANIZATIONAL LEARNING
Mainert, Jakob Simon UL

Doctoral thesis (2017)

This thesis investigates the empirical assessment and construct validity of complex problem-solving (CPS) skills and organizational learning (OL) in a changing nature of work. Technological and ... [more ▼]

This thesis investigates the empirical assessment and construct validity of complex problem-solving (CPS) skills and organizational learning (OL) in a changing nature of work. Technological and organizational change enlarge the gap between the type of employee required by the market and the employees who are actually being provided by higher education as human capital to the market. Two constructs, CPS and OL, might strengthen human capital to close the emerging gap in a changing nature of work. [less ▲]

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See detailL'intégration des élèves nouvellement arrivés en France dans l'espace scolaire français. Langues, représentations, identités en contexte.
Kadas, Timea UL

Doctoral thesis (2017)

Our thesis focuses on newcomer students in France and aims at understanding how these students integrate into French schools and exploring the educational paths they tread. Thus, this study is based ... [more ▼]

Our thesis focuses on newcomer students in France and aims at understanding how these students integrate into French schools and exploring the educational paths they tread. Thus, this study is based mainly on the analysis of the discourse of thirteen students concerning their learning and their school experiences. It is also based on the representations that these students have of themselves, others (French students, teachers), their learning in general, their learning of the French language in particular and the context in which this learning takes place. Our thesis also focuses on the students’ first languages and their role in the learning process. The link between language and identity has long been established by researchers from different disciplines. Therefore, we have tried to understand, through an autobiographical project based on the notions of multiliteracy and multimodality, how the first languages of the students can be taken into consideration in order to help them progress in both the learning of French and learning in general. We also considered the significance of such an approach in the reconstruction of these students' identities. Furthermore, in response to our initial question regarding how these students integrate into the French education system, we investigated two complementary perspectives: that of the institution through interviews with three teachers, three heads of school and two inspectors and that of the students’ families through questioning nine parents. The aim of this study is to contribute to the body of research on the role of migration in the French educational context and to provide a better understanding of the current educational challenges facing our globalized society. [less ▲]

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See detailStem cells for modeling Parkinson's disease
Nickels, Sarah Louise UL

Doctoral thesis (2017)

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See detailInflammatory signaling in liver cells: Cross-regulation of the IL-6/JAK/STAT3 pathway and microRNAs
Servais, Florence UL

Doctoral thesis (2017)

Interleukin-6 (IL-6) plays important roles in the regulation of liver functions and promotes the development of hepatocellular carcinoma (HCC), the most common primary liver cancer. Whereas protein ... [more ▼]

Interleukin-6 (IL-6) plays important roles in the regulation of liver functions and promotes the development of hepatocellular carcinoma (HCC), the most common primary liver cancer. Whereas protein-encoding genes are well-studied, the contribution of IL-6-regulated microRNAs (miRNAs) to its effects is largely unexplored. Similarly, little is known about miRNAs regulating key molecules of the IL-6/JAK/STAT3 signaling pathway. In the main part of this thesis, cell-based high-throughput screenings systems were developed, allowing the identification of miRNAs interfering with the IL-6/JAK/STAT3 signaling. Out of 538 miRNA mimics, this dual screening approach followed by various validation steps (luciferase-3’UTR-reporter assays, western blot and flow cytometry analyses) allowed us to identify twelve miRNAs targeting STAT3, JAK1, SOCS3, IL6R and/or gp130, ten of them had not yet been reported as regulators of this pathway before. In the second part of this work, microarray analyses revealed that primary hepatocytes are considerably more responsive to IL-6 stimulation regarding changes in their miRNomes than liver-derived cell lines. Despite their weaker response, one of the top regulated miRNA found in the primary hepatocytes, miR-146b-5p, could also be induced by IL-6-type cytokines (IL-6 and Oncostatin M) in cell lines. Its functional role(s) in hepatocytes are currently investigated. A larger, comparative study included additionally Interferon gamma and IL-27, cytokines with a STAT1-dominated response, and supplementary cell lines originating not only from the liver but also from other tissues. While all cytokines had profound effects on the mRNA transcriptomes, only very small to moderate changes were observed at the miRNome level, suggesting that the regulation mediated by cytokines mainly happens through the modulation of protein-coding genes rather than by fine-tuning via miRNAs. Additionally, we analyzed expression of a broad panel of cytokines in sera of 125 patients with liver diseases (steatosis, non-alcoholic steatohepatitis, HCC) by bead-based multiplex immunoassays. We observed that, for example, serum HGF, IL-6 and IL-8 levels increased in relation with the severeness of liver pathology while PDGF-BB and RANTES decreased. When investigating the impact of the patatin-like phospholipase domain-containing protein 3 variant I148M (PNPLA3 I148M), known to be a risk factor for the development of liver diseases, on the serum levels of cytokines, no significant differences could be observed between the different genotypes. In this PhD thesis, we identified and characterized miRNAs relevant for the IL-6/JAK/STAT3 signaling pathway, including miR-146b-5p as an IL-6-inducible miRNA. Others like miR-194-5p, miR-4473 and miR-548k were demonstrated to be negative regulators of this pathway and may be of potential therapeutic significance. In addition, we showed that, while miRNAs can modulate this pathway, IL-6 seems to rather regulate the mRNA transcriptome than the miRNome. [less ▲]

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See detailKusuoka-Stroock type bounds for densities related to low-dimensional projections of high-dimensional SDE
Ledent, Antoine Patrick Isabelle Eric UL

Doctoral thesis (2017)

One of the purposes of this thesis is to use Malliavin calculus and Stochastic Taylor expansions to study the densities of interacting systems of stochastic differential equations (SDE), seen as ... [more ▼]

One of the purposes of this thesis is to use Malliavin calculus and Stochastic Taylor expansions to study the densities of interacting systems of stochastic differential equations (SDE), seen as projections of SDE onto a low-dimensional space, and to control the dependence of the constants on the dimension of the background space. The setting includes time-dependent SDE and a relatively large class of path-dependent SDE. Several results also shed light on the classical theory of SDE, independently of the control on the constants. In Part 1, assuming the system satisfies suitably defined projected equivalents of the classic ellipticity or weak Hörmander conditions, we prove Gaussian estimates in terms of the Euclidean distance where, provided natural assumptions, for a fixed target-space dimension, the constants depend polynomially on the background dimension, and, in the elliptic case, on the number of driving Brownian motions. In Part 2, we first define suitable generalisations of (time-dependent) control distances and prove Kusuoka-Stroock type results without control on the constants. In particular, we obtain a time-dependent extension of a result of Léandre about SDE with non-trivial drifts, i.e., drifts which are not uniformly contained in the span of the other vector fields. Then, we introduce a condition which we call the `Progressive Hörmander condition' and prove similar control-type estimates valid under this assumption, with polynomial control on the growth of the constants with background space dimension. The condition is of independent interest in the study of SDE, and shows the connection between the classic works of Ben Arous, Kusuoka, Léandre and Stroock, and the more recent works of Bally, Caramellino, Delarue, Menozzi and Pigato. To main technique required is the study of density and scaling properties of some careful choice of linear combinations of terms of the signature of the driving path. In Part 3, we introduce a stricter condition called the `separated progressive Hörmander condition', and prove lower bounds and local strict positivity under this assumption. (By `local' we mean local around the solution of the deterministic ODE driven by a null control, rather than local round the initial point.) The main technical difficulty is the identification of points contained in the interior of the support of the log-signature of the path in the d dimensional Euclidean space composed of d Brownian motions and a deterministic linear component. The purpose of Part 4 is to use some results and techniques of the rest of the thesis to prove extensions of a theorem of Löcherbach about uniformly elliptic interacting branching diffusions. [less ▲]

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See detailMolecular mechanisms of kinase inhibitor resistance in melanoma
Cesi, Giulia UL

Doctoral thesis (2017)

In my thesis, I elucidated several aspects of melanoma biology, all related to the influence of targeted therapies in both responding and resistant melanoma cells. To better understand the MAPK signalling ... [more ▼]

In my thesis, I elucidated several aspects of melanoma biology, all related to the influence of targeted therapies in both responding and resistant melanoma cells. To better understand the MAPK signalling pathway, the impact of BRAF inhibitors on metabolic alterations as well as the connection between BRAF inhibitors and the onset of drug resistance was investigated. This introduction is focused on four topics: i) melanoma, ii) cancer metabolism, iii) miRNAs and iv) extracellular vesicles. First, melanoma biology including incidence rates, etiology, canonical and altered signalling pathways, therapies and resistance mechanisms will be introduced. The second part of the introduction will concentrate on metabolic alterations in the context of cancer and their implication on proliferation and survival. Thirdly, miRNAs and extracellular vesicles will be illustrated providing insights into their role in cancer development and especially drug resistance [less ▲]

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See detailCHARACTERIZATION OF PARKINSON’S DISEASE GENE DJ-1/PARK7 IN CD4+CD25+FOXP3+ REGULATORY T-CELLS
Danileviciute, Egle UL

Doctoral thesis (2017)

DJ-1, also known as PARK7, as its name suggests, is one of the familial Parkinson’s disease (PD) genes. Defects in human DJ-1 are the cause of autosomal recessive early-onset PD. DJ-1 is a redox ... [more ▼]

DJ-1, also known as PARK7, as its name suggests, is one of the familial Parkinson’s disease (PD) genes. Defects in human DJ-1 are the cause of autosomal recessive early-onset PD. DJ-1 is a redox-responsive protein and is long thought to mainly play an essential protective role in neurons. DJ-1 is ubiquitously expressed throughout the body rather than only in brain and is involved in several biological functions. We here seek to characterize a novel role of DJ-1 in regulatory T cells, currently recognized as CD4+CD25+FOXP3+ regulatory T-cells (Tregs), which are well-known immune suppressor cells in many peripheral diseases and emerging to play a role in several neurodegenerative diseases. [less ▲]

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See detailAutomated and Effective Security Testing for XML-based Vulnerabilities
Jan, Sadeeq UL

Doctoral thesis (2017)

Nowadays, the External Markup Language (XML) is the most commonly used technology in web services for enabling service providers and consumers to exchange data. XML is also widely used to store data and ... [more ▼]

Nowadays, the External Markup Language (XML) is the most commonly used technology in web services for enabling service providers and consumers to exchange data. XML is also widely used to store data and configuration files that control the operation of software systems. Nevertheless, XML suffers from several well-known vulnerabilities such as XML Injections (XMLi). Any exploitation of these vulnerabilities might cause serious and undesirable consequences, e.g., denial of service and accessing or modifying highly-confidential data. Fuzz testing techniques have been investigated in the literature to detect XMLi vulnerabilities. However, their success rate tends to be very low since they cannot generate complex test inputs required for the detection of these vulnerabilities. Furthermore, these approaches are not effective for real-world complex XML-based enterprise systems, which are composed of several components including front-end web applications, XML gateway/firewall, and back-end web services. In this dissertation, we propose several automated security testing strategies for detecting XML-based vulnerabilities. In particular, we tackle the challenges of security testing in an industrial context. Our proposed strategies, target various and complementary aspects of security testing for XML-based systems, e.g., test case generation for XML gateway/firewall. The development and evaluation of these strategies have been done in close collaboration with a leading financial service provider in Luxembourg/Switzerland, namely SIX Payment Services (formerly known as CETREL S.A.). SIX Payment Services processes several thousand financial transactions daily, providing a range of financial services, e.g., online payments, issuing of credit and debit cards. The main research contributions of this dissertation are: -A large-scale and systematic experimental assessment for detecting vulnerabilities in numerous widely-used XML parsers and the underlying systems using them. In particular, we targeted two common XML parser’s vulnerabilities: (i) XML Billion Laughs (BIL), and (ii) XML External Entities (XXE). - A novel automated testing approach, that is based on constraint-solving and input mutation techniques, to detect XMLi vulnerabilities in XML gateway/firewall and back-end web services. - A black-box search-based testing approach to detect XMLi vulnerabilities in front-end web applications. Genetic algorithms are used to search for inputs that can manipulate the application to generate malicious XML messages. - An in-depth analysis of various search algorithms and fitness functions, to improve the search-based testing approach for front-end web applications. - Extensive evaluations of our proposed testing strategies on numerous real-world industrial web services, XML gateway/firewall, and web applications as well as several open-source systems. [less ▲]

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See detailCRISPR/CAS9 AND PIGGYBAC MEDIATED LRRK2-G2019S IN VITRO PARKINSON’S DISEASE MODELING
Qing, Xiaobing UL

Doctoral thesis (2017)

Parkinson’s disease (PD), the second most common neurodegenerative disorder, is characterized by the progressive loss of dopaminergic (DA) neurons in the substantial nigra pars compacta (SNpc) area of the ... [more ▼]

Parkinson’s disease (PD), the second most common neurodegenerative disorder, is characterized by the progressive loss of dopaminergic (DA) neurons in the substantial nigra pars compacta (SNpc) area of the human midbrain with an unclear cause. Mutations revealed by whole genome sequencing (WGS) from familial PD cases may explain how cell loss occurs. Confirmation of this hypothesis has been hampered by the lack of available cell types from affected patients. Transgenic animal models have been used, but differences between these animals and humans have greatly impacted their usefulness for studying human diseases. Additionally, because PD is regarded to only affect humans, reliable human material-based experimental models are urgently needed. Human-induced pluripotent stem cells (hiPSCs)- derived DA neurons provide an opportunity to establish in vitro mutation-related PD models of disease-relevant cells that represent replacement alternatives to in vivo animal experiments. However, these hiPSCs-based PD models have limitations regarding the genetic background differences between patients and healthy controls. Genomic editing of hiPSCs allows for the generation of isogenic cellular models that differ only in the disease-specific mutations of interest. Currently, the biggest concern regarding nuclease-mediated genomic editing is the potentially undesirable alterations associated with remnant sequences, off-target effects and random integration, which may result in cell lines not being truly isogenic. To avoid potential confounding effects and establish a causal link between genotype and phenotype, robust isogenic cell lines free of unwanted mutagenesis are absolutely required for the study of PD. To better understand the pathogenesis of the most prevalent leucine-rich repeat kinase 2 (LRRK2) mutation, G2019S, which causes both familial and sporadic PD, patient hiPSCs have been corrected using the Cre/LoxP recombination system. However, the LoxP site inevitably remaining after excision of the selection cassette can influence gene expression. In this thesis, a “footprint-free” LRRK2-G2019S isogenic model was created using clustered regularly interspaced short palindromic repeats/Cas9-associated (CRISPR/Cas9) system and a piggyBac transposon that can remove selection cassettes without leaving remnants. In LRRK2-G2019S DA neurons, the percentage of tyrosine hydroxylase (TH)-positive neurons with a total neurite length greater than 2 cm was significantly reduced, and the average branch number was also decreased. These PD-like phenotypes could be rescued by administration of the specific LRRK2 inhibitor LRRK2-IN-1 and by the compound BRF110, which activates the Nurr1:RXRa heterodimer to replenish the DA shortage. Our data suggest that the “footprint- free” LRRK2-G2019S isogenic cell lines allow standardized, genetic background-independent, in vitro PD modeling and are suitable for screening novel drugs that have clinical applications. In addition, we have shown that in vitro TH-positive neurons with a total neurite length greater than 2 cm were positive for serine 129 phosphorylated (S129P) α-synuclein, and we hypothesize that S129P α-synuclein plays a role in the maintenance or formation of long neurites. Thus, we have also provided new insights into the roles of LRRK2-G2019S and S129P α-synuclein in PD pathogenesis. Furthermore, we have optimized CRISPR/Cas9-mediated genomic editing in hiPSCs by establishing a FACS-assisted CRISPR/Cas9 editing (FACE) strategy that uses three fluorescent proteins to isolate biallelic-edited cells with no random integration and by using Exonuclease III (ExoIII)-facilitated long single stranded DNA (ssDNA) donor to reduce random integration. [less ▲]

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See detailAutomated requirements-driven testing of embedded systems based on use case specifications and timed automata
Wang, Chunhui UL

Doctoral thesis (2017)

The complexity of embedded software in safety-critical domains, such as automotive and avionics, has significantly increased over the years. For most embedded systems, standards require system testing to ... [more ▼]

The complexity of embedded software in safety-critical domains, such as automotive and avionics, has significantly increased over the years. For most embedded systems, standards require system testing to explicitly demonstrate that the software meets its functional and safety requirements. In these domains, system test cases are often manually derived from functional requirements in natural language plus other design artefacts, like UML statecharts. The definition of system test cases is therefore time-consuming and error-prone, especially given the quickly rising complexity of embedded systems. The benefits of automatic test generation are widely acknowledged today but existing approaches often require behavioural models that tend to be complex and expensive to produce, and are thus often not part of development practice. The work proposed in this dissertation focusses on the automated generation of test cases for testing the compliance between software and its functional and timing requirements. This dissertation is inspired by contexts where functional and timing requirements are expressed by means of use case specifications and timing automata, respectively. This is the development context of our industrial partner, IEE, an automotive company located in Luxembourg, who provided the case study used to validate the approach and tool described in this dissertation. This dissertation presents five main contributions: (1) A set of guidelines for the definition of functional and timing requirements to enable the automated generation of system test cases. (2) A technique for the automated generation of functional test cases from requirements elicited in the form of use case specifications following a prescribed template and natural-language restrictions. (3) A technique that reuses the automatically generated functional test cases to generate timeliness test cases from minimal models of the timing requirements of the system. (4) A technique for the automated generation of oracles for non-deterministic systems whose specifications are expressed by means of timed automata. In the context of this dissertation, automated oracles for non-deterministic systems are necessary to evaluate the results of the generated timeliness test cases. (5) The evaluation of the applicability and effectiveness of the proposed guidelines and techniques on an industrial case study, a representative automotive embedded system developed by IEE. [less ▲]

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See detailProjectional Editing of Software Product Lines–The PEoPL approach
Behringer, Benjamin UL

Doctoral thesis (2017)

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See detailActive Learning in Cognitive Radio Networks
Tsakmalis, Anestis UL

Doctoral thesis (2017)

In this thesis, numerous Machine Learning (ML) applications for Cognitive Radios Networks (CRNs) are developed and presented which facilitate the e cient spectral coexistence of a legacy system, the ... [more ▼]

In this thesis, numerous Machine Learning (ML) applications for Cognitive Radios Networks (CRNs) are developed and presented which facilitate the e cient spectral coexistence of a legacy system, the Primary Users (PUs), and a CRN, the Secondary Users (SUs). One way to better exploit the capacity of the legacy system frequency band is to consider a coexistence scenario using underlay Cognitive Radio (CR) techniques, where SUs may transmit in the frequency band of the PU system as long as the induced to the PU interference is under a certain limit and thus does not harmfully a ect the legacy system operability. [less ▲]

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See detailDamage detection in prestressed concrete bridges based on static load testing, sagging and modal parameters, using measurements and model updating
Schommer, Sebastian UL

Doctoral thesis (2017)

Bridges are an essential part of nowadays infrastructure to cross natural and artificial obstacles like rivers, valleys or other roads and railways. Many concrete bridges were built in the last 70 years ... [more ▼]

Bridges are an essential part of nowadays infrastructure to cross natural and artificial obstacles like rivers, valleys or other roads and railways. Many concrete bridges were built in the last 70 years. The traffic density has increased immensely over the last decades and the bridges are suffering from corrosion and wear. Nevertheless, the safety of the infrastructure has to be guaranteed and therefore it is very important to find efficient methods for structural health monitoring. For this purpose, visual inspections are the most widely adopted in reality today. Considering the size of most bridge structures, it is understandable that these tests are generally very time-consuming and many personnel are needed, so they are cost-intensive. However, it is not always guaranteed that all damage can be found as only the surface is accessible. For instance, internal damage, such as corrosion of passive reinforcements or prestressed tendons, is difficult to detect. In addition, small cracks can remain undetected when covered by paints or dirt. Therefore, it is important to complement the standard methods with advanced alternatives. The aim is therefore not necessarily to replace visual inspections, but rather to find efficient methods for amendment. An idea being vigorously discussed in the scientific community is based on vibration measurements of a structure to assess its dynamic behaviour. The occurrence of damage will change the system properties, as it changes above all the stiffness distribution. So the system identification process in principle allows detection of changes of eigenfrequencies and hence stiffness. The main problem in practice on real bridges is that the robustness of a method is often insufficient, as the measured parameters are often also influenced by temperature changes. It will be shown that the impact of temperature change, e.g. between night and day, on the system properties is much higher than the influence of small damage. Furthermore, changes in soil and bearing conditions between different seasons can play a role. These environmental effects have to be taken into account while performing measurements for damage assessment. For this purpose, strategies are proposed to compensate environmental effects. Therefore, this thesis focuses on measurements under real environmental conditions, outside a laboratory. Different methods for damage assessment or stiffness tracking based on measured static and on dynamic properties of structures are deployed. Finally, the measured and analysed physical properties of the bridges in this thesis are: eigenfrequencies, mode shapes, sagging under own weight and the deflection line under a static test-loading. These quantities are tracked and artificial damage is introduced stepwise to a test-beam of a real bridge. Damage assessment and localisation is tried directly with the measured quantities but also by model-updating of a finite element model. This solid model is divided in a special way in different slices. It is possible to change the stiffness distribution along the axis of the simulated beam by varying the Young’s moduli of these slices. Furthermore, to reduce the number of free parameters for the subsequent up-dating process, an exponential damage function is introduced that describes the stiffness distribution. At first, the model was designed to fit a healthy reference state. Now measurement data from the artificially damaged test-beam are introduced and the model is updated by changing the Young’s moduli of the slices to minimise a special objective function containing the measured and simulated physical quantities. The comparison of initial and updated model allows a quantification and localisation of damage. Finally, the slice width is reduced around the identified damage region to improve the process. [less ▲]

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See detailObservation and Control of Anaerobic Digestion Processes for Improved Biogas Production
Chaib Draa, Khadidja UL

Doctoral thesis (2017)

In this thesis, we propose a formal modelling framework for the anaerobic digestion process, where we add more degrees of freedom in the control of biogas production. Indeed, we add two additional control ... [more ▼]

In this thesis, we propose a formal modelling framework for the anaerobic digestion process, where we add more degrees of freedom in the control of biogas production. Indeed, we add two additional control inputs to the standardized AM2 (Acidogenesis Methanogenesis, 2 steps) model, re ecting addition of stimulating substrates which enhance the biogas quality and quantity. Then, we describe how the parameters of the resulted nonlinear model can be identi ed, and we analyse the positiveness and boundedness of its state variables. Based on the derived mathematical model and the analysis results, we design di erent software sensors to overcome the lack of reliable and cheap sensors. Indeed, we present a general class of systems to which the considered process model belongs. Then, we design an LMI-based invariant like observer as well as an LMI-based nonlinear observer of the same form as the generalized Arcak's observer. Furthermore, with the aim to render the observer design more robust to disturbances, we include the H1 criterion in its synthesis. Also, to promote the use of the proposed observers in real applications, we extend the methodology to the discrete time case and to the case of nonlinear systems with nonlinear outputs. For the di erent observers design, we use the di erential mean value theorem which allows the transformation of the nonlinear estimation error to a linear parameter varying system. Then, we use the Lipschitz conditions and the Lyapunov standard function to synthesize the stability conditions in the form of linear matrix inequalities. Finally, we enhance the feasibility of the later conditions by using a judicious reformulation of the Young's inequality. In the thesis, we also deal with the process control where we propose a control strategy to track an admissible reference trajectory planned by the plant operator. Moreover, to account for the partial availability of the state vector measurements, we include an exponential nonlinear observer in the control synthesis. Thus, we design an observer based tracking control scheme. To perform the stability analysis of the closed loop system, composed of the system, the observer and the controller, we use the Barbalat's lemma conjointly with the techniques already mentioned for the observers design. Finally, we propose two different methods to compute the controller and the observer parameters. In the first one, we propose to compute them separately. While, in the second one we compute the parameters simultaneously. [less ▲]

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See detailAchtsamkeit als Determinante von Glück im Alter - Theoretische und Empirische Analysen
Theisen, Marie-Paule Gaby UL

Doctoral thesis (2017)

In den späten siebziger Jahren entwickelte der Molekularbiologe und Zen-Praktiker Jon Kabat-Zinn in den USA das „Mindfulness-Based Stress Reduction Program – MBSR“ (dt.: das Programm zur Stressreduzierung ... [more ▼]

In den späten siebziger Jahren entwickelte der Molekularbiologe und Zen-Praktiker Jon Kabat-Zinn in den USA das „Mindfulness-Based Stress Reduction Program – MBSR“ (dt.: das Programm zur Stressreduzierung durch Achtsamkeit). Der Medizinprofessor begann mit Erfolg, das Programm an Schmerzpatienten der University of Massachusetts Medical School Stress Reduction Clinic zu vermitteln. Parallel dazu untersuchte der Forscher die Auswirkungen dieses Stressreduzierungsprogramms auf das psychische und physische Wohlbefinden der Patienten. Diese Forschungsergebnisse veranlassten mich dazu, das bestehende Programm MBSR an die Bedürfnisse und Wünsche von gesunden, existenziell verängstigten, gestressten Menschen im Vorrentenalter und Rentenalter anzupassen und das Programm „Achtsamkeit Entdecken – Leben im Augenblick“ (AELA) für Senioren zu entwickeln. Als theoretische Grundlage dieses Programms wurden einschlägige Theorien zu Achtsamkeit, Glück und dem Alternsprozess beschrieben und in ihrem Zusammenhang elaboriert. Anschließend daran wurden über eine Kombination von quantitativem und qualitativem Vorgehen die Nützlichkeit und die Wirkungen von Achtsamkeit auf das Glücksempfinden „betagter“ Menschen im Alltag untersucht. Im Rahmen einer quantitativ angelegten Trainingsstudie wurden über den Zeitraum von vier Wochen Achtsamkeitselemente vermittelt, die über die Selbstberichte der Teilnehmer evaluiert wurden. Insgesamt zeichneten sich dabei positive Effekte auf das Befinden der Teilnehmer ab und diese betrachteten die Achtsamkeitsübungen als nützlich, um bewusster zu leben. Im Rahmen einer qualitativen Studie wurden fünfzehn Interviews zum Leben im Alter durchgeführt und dabei unterschiedliche Aspekte – wie z.B. Wünsche und Ziele, aber auch Ängste und Befürchtungen – exploriert. In den Interviews wurde zudem erfragt, inwieweit die Personen bereits mit dem Konzept der Achtsamkeit vertraut sind und inwieweit sie dieses nutzen. Auch diese Studie belegt die Bedeutsamkeit dieses Konzeptes für das Leben im Alter. Alle Befunde sprechen somit dafür, dass der gesunde ältere Mensch durch eine regelmäßige Achtsamkeitspraxis – im Sinne eines bewussten Lebens von Augenblick zu Augenblick – Stressfreiheit und Glück erfahren kann.   [less ▲]

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See detailAUTOMATED DEBUGGING AND FAULT LOCALIZATION OF MATLAB/SIMULINK MODELS
Liu, Bing UL

Doctoral thesis (2017)

Matlab/Simulink is an advanced environment for modeling and simulating multidomain dynamic systems. It has been widely used to model advanced Cyber-Physical Systems, e.g. in the automotive or avionics ... [more ▼]

Matlab/Simulink is an advanced environment for modeling and simulating multidomain dynamic systems. It has been widely used to model advanced Cyber-Physical Systems, e.g. in the automotive or avionics industry. To ensure the reliability of Simulink models (i.e., ensuring that they are free of faults), these models are subject to extensive testing to verify the logic and behavior of software modules developed in the models. Due to the complex structure of Simulink models, finding root causes of failures (i.e., faults) is an expensive and time-consuming task. Therefore, there is a high demand for automatic fault localization techniques that can help en- gineers to locate faults in Simulink models with less human intervention. This demand leads to the proposal and development of various approaches and techniques that are able to automatically locate faults in Simulink models. Fault localization has been an active research area that focuses on developing automated tech- niques to support software debugging. Although there have been many techniques proposed to localize faults in programs, there has not been much research on fault localization for Simulink models. In this dissertation, we investigate and develop a lightweight fault localization approach to automatically and accurately locate faults in Simulink models. To enhance the usability of our approach, we also develop a stand-alone desktop application that provides engineers with a usable interface to facilitate localization of faults in their models. [less ▲]

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See detailParkinson's disease: Evaluation of a neuroprotective target and identification of candidate biomarker signatures using murine models
Ashrafi, Amer UL

Doctoral thesis (2017)

Parkinson's disease (PD) is one of the most common age-related neurologic diseases. While existing therapeutic approaches, focusing on dopamine replacement, can alleviate some of the cardinal symptoms ... [more ▼]

Parkinson's disease (PD) is one of the most common age-related neurologic diseases. While existing therapeutic approaches, focusing on dopamine replacement, can alleviate some of the cardinal symptoms, they are associated with severe adverse effects in the long-term. Therefore, identification of new therapeutic interventions to reverse, stop or slow down the progression of Parkinson’s disease is a major focus of PD research. Similarly, identifying reliable biomarkers that would enable early therapeutic intervention is another key area of current research. Here, we evaluated a recently proposed non-dopaminergic protein drug target for PD, Regulator of G-Protein Signaling 4 (RGS4), and performed preliminary studies aimed at the identification of novel biomarker signatures using two murine models of Parkinson’s disease. Recent research on new non-dopaminergic PD drug targets has indicated that inhibition of RGS4, a member of the RGS family of proteins that inactivate G-proteins, could be an effective adjuvant treatment option. However, the effectiveness of RGS4 inhibition for an array of PDlinked functional and structural neuroprotection endpoints had not yet been demonstrated. Here, we used the 6-Hydroxydopamine (6-OHDA) lesioning mouse model to address this question. We observed, using a battery of behavioral and pathological measures, that mice deficient for RGS4 are not protected from 6-OHDA induced injury, and showed enhanced susceptibility in some measures of motor function. Our results suggest that inhibition of RGS4 as a non-dopaminergic target for PD should be approached with caution. In the second part of this study, two alpha-synuclein based PD mouse models, human E46K mutated overexpressed alpha-synuclein and alpha-synuclein fibril spreading models, were used to investigate early pathological events in PD and identify novel candidate biomarker signatures for subsequent validation. Two different time points, before disease onset, and at peak disease manifestation, were analyzed in the two models. Using multiple histopathology and molecular biology techniques, we were able to identify complex changes in patterns of gene expression at early stages of the disease, well before neurodegeneration is detectable. These findings might open venues for new therapeutic strategies and provide insights on the molecular perturbations occurring during the earliest stages of the disease, paving the way for the development of a biomarker signatures for early diagnosis of Parkinson’s disease. [less ▲]

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See detailThe Europeanisation of German, French and Luxembourgish Economic Interest Groups: The Case of the Blue Card Directive Policy-Making Process
Foltête Usage Paris, Sidonie UL

Doctoral thesis (2017)

The Europeanisation of interest groups has been the subject of a substantial academic literature. Yet, multi-level venue shopping has stirred relatively little attention and the cognitive dimension of ... [more ▼]

The Europeanisation of interest groups has been the subject of a substantial academic literature. Yet, multi-level venue shopping has stirred relatively little attention and the cognitive dimension of actors’ Europeanisation has remained largely untouched. This research project addresses these shortcomings by exploring the degree to which business organisations and labour unions deploy their activities at the level of the European Union (i.e. ‘strategic Europeanisation’) and the causal effects of European integration on interest organisations’ shift of perception (i.e. ‘cognitive Europeanisation). This dual perspective is applied to the study of German, French, and Luxembourgish actors’ behaviours in the case of the Blue Card Directive policy-making process. Results on ‘strategic Europeanisation’ reveal a high inclination of German actors to resort to multi-level lobbying in the Blue Card Directive policy-making process and a conversely low propensity of their French counterparts to activate the supranational arena. Luxembourgish stakeholders show very little drive to activate their EU-level lobbying channels. Specific findings point to the importance of financial resources and actors’ domestic embeddedness when deciding whether to make use of Europe, although in contrasted ways. As regards ‘cognitive Europeanisation’, the study shows that the European Union did not shape actors’ shift of perception on labour immigration across the three countries under examination. [less ▲]

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See detailInterpretive Interactions among Legal Systems and Argumentation Schemes
Malerba, Alessandra UL

Doctoral thesis (2017)

This thesis is about argumentation schemes that help to deal with interactions between national and foreign canons of interpretation in private international law cases. In fact, many legal orders, like ... [more ▼]

This thesis is about argumentation schemes that help to deal with interactions between national and foreign canons of interpretation in private international law cases. In fact, many legal orders, like Italy, require that, in conflict of laws disputes, courts apply the relevant foreign law using canons of interpretation and rules of application of the original foreign system. Our research hypothesis is that, in interpreting the foreign rule, domestic courts incur interpretive divergences of many kinds among the involved legal systems. Foreign law interpretation may result in linguistic and/or conceptual misalignments, in normative and/or interpretive gaps, and in specific incompatibilities between inner and foreign canons of interpretation. By focusing on interpretive conflicts within one legal system, legal theorists and AI and Law scholars have not yet paid sufficient attention to the issue, even if pluralist logics and argumentation have been generally applied to legal pluralism and conflict of laws. The present study fills this gap in the literature: it explores the feasibility of a theory for arguing and interpreting in private international law contexts, providing an argument-based conceptual framework that encompasses plausible interpretive interactions. To this end, and after addressing the epistemic concerns foreign law raises for domestic judges, the thesis gives a definition of cross-border interpretive incompatibilities and proposes argumentation schemes to reason with interpretive canons coming from different legal systems. An illustrative list of critical questions is used to evaluate the correctness of such interpretive reasoning. Lastly, the thesis presents the first formal developments of the study, based on the concept of meta-argumentation. It is possible to detect two main contributions to knowledge. First, this work identifies the components of foreign law interpretation, an interpretation activity with significant practical implications for legal systems today. In so doing, it also indirectly contributes to better understand interpretation at large. Secondly, its argument-based analysis paves the way for further formal applications in the domain of AI and Law. [less ▲]

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See detailDevelopment and analysis of individual-based gut microbiome metabolic models
Magnusdottir, Stefania UL

Doctoral thesis (2017)

The human gut microbiota plays a large role in the metabolism of our diet. These microorganisms can break down indigestible materials such as polysaccharides and convert them into metabolites that the ... [more ▼]

The human gut microbiota plays a large role in the metabolism of our diet. These microorganisms can break down indigestible materials such as polysaccharides and convert them into metabolites that the human body can take up and utilize (e.g., vitamins, essential amino acids, and short-chain fatty acids). Disbalances in the gut microbiome have been associated with several diseases, including diabetes and obesity. However, little is known about the detailed metabolic crosstalk that occurs between individual organisms within the microbiome and between the microbiome and the human intestinal cells. Because of the complexity of the intestinal ecosystem, these interactions are difficult to determine using existing experimental methods. Constraint-based reconstruction and analysis (COBRA) can help identify the possible metabolic mechanisms at play in the human gut. By combining mathematical, computational, and experimental methods, we can generate hypotheses and design targeted experiments to elucidate the metabolic mechanisms in the gut microbiome. In this thesis, I first applied comparative genomics to analyze the biosynthesis pathways of eight B-vitamins in hundreds of human gut microbial species. The results suggested that many gut microbes do not synthesize any B-vitamins, that is, they depend on the host’s diet and neighboring bacteria for these essential nutrients. Second, I developed a semi-automatic reconstruction refinement pipeline that quickly generates biologically relevant genome-scale metabolic reconstructions (GENREs) of human gut microbes based on automatically generated metabolic reconstructions, comparative genomics data, and data extracted from biochemical experiments on the relevant organisms. The pipeline generated metabolically diverse reconstructions that maintain high accuracy with known biochemical data. Finally, the refined GENREs were combined with metagenomic data from individual stool samples to build personalized human gut microbiome metabolic reconstructions. The resulting large-scale microbiome models were both taxonomically and functionally diverse. The work presented in this thesis has enabled the generation of biologically relevant human gut microbiome metabolic reconstructions. Metabolic models resulting from such reconstructions can be applied to study metabolism within the human gut microbiome and between the gut microbiome and the human host. Additionally, they can be used to study the effects of different dietary components on the metabolic exchanges in the gut microbiome and the metabolic differences between healthy and diseased microbiomes. [less ▲]

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See detailThe politics of knowledge that govern the European Union lifelong learning policy space – A Foucauldian reading
Rizzo, Stephen UL

Doctoral thesis (2017)

This contemporary historical research calls into question the mentalities that construct the EU lifelong learning policy space in specific ways. By drawing on the Foucauldian concepts of governmentality ... [more ▼]

This contemporary historical research calls into question the mentalities that construct the EU lifelong learning policy space in specific ways. By drawing on the Foucauldian concepts of governmentality and genealogy, this thesis analyses selected main EU lifelong learning policy literature by focusing on how this space has been articulated in governable forms. In line with a Foucauldian interpretation of power, the EU as a subject is decentred and considered as an epistemological form of assumption so that power and knowledge are analysed according to how they operate in this space. The governmentalist approach explores the technologies of the self and the technologies of government that construct and govern the conduct of conduct of the subject through the recurrent narratives in this space. In combination with this approach, the genealogical analysis of the episteme lifelong learning traces the different terminological interpretations which have been systematically reconfigured throughout the years to attain new connotations. These different connotations are problematised not only because the distinctiveness of the definition influenced the trajectory lifelong learning took throughout the years, but also because lifelong learning can, at one and the same time, control or liberate people. The distinctive contribution to academic literature that this thesis achieves is that it problematises the unquestionable truths that construct the EU lifelong learning policy space from a non-normative point of view. The overriding idea is for the actors in this space to make visible the taken-for granted principles and to create the possibility to challenge prevailing power relations and challenge what is uncritically taken as natural. [less ▲]

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See detailComputational Aspects of Classical and Hilbert Modular Forms
van Hirtum, Jasper UL

Doctoral thesis (2017)

The main topic of this thesis is the study of classical and Hilbert modular forms and computational aspects of their q-expansions. The coefficients of q-expansions of eigenforms are particularly ... [more ▼]

The main topic of this thesis is the study of classical and Hilbert modular forms and computational aspects of their q-expansions. The coefficients of q-expansions of eigenforms are particularly interesting because of their arithmetic significance. Most notably, modular forms are an essential ingredient in Andrew Wiles’s proof of Fermat’s last theorem. This thesis consists of two parts: the first part concerns the distribution of the coefficients of a given classical eigenform; the second part studies computational aspects of the adelic q-expansion of Hilbert modular forms of weight 1. Part I of this thesis is an adapted version of the article On the Distribution of Frobenius of Weight 2 Eigenforms with Quadratic Coefficient Field published in Experimental Mathematics [38]. It presents a heuristic model that settles the following question related to the Sato-Tate and Lang-Trotter conjectures: given a normalised eigenform of weight 2 with quadratic coefficient field, what is the asymptotic behaviour of the number of primes p such that the p-th coefficient of this eigenform is a rational integer? Our work contributes to this problem in two ways. First, we provide an explicit heuristic model that describes the asymptotic behaviour in terms of the associated Galois representation. Secondly, we show that this model holds under reasonable assumptions and present numerical evidence that supports these assumptions. Part II concerns the study of (adelic) q-expansions of Hilbert modular forms. Our main achievements are the design, proof and implementation of several algorithms that compute the adelic q-expansions of Hilbert modular forms of weight 1 over C and over finite fields. One reason we are studying such q-expansions is that their coefficients (conjecturally) describe the arithmetic of Galois extensions of a totally real number field with Galois group in GL 2 (F p ) that are unramified at p. Using the adelic q-expansions of Hilbert modular forms of higher weight, these algorithms enable the explicit computation of Hilbert modular forms of any weight over C and the computation of Hilbert modular forms of parallel weight both over C and in positive characteristics. The main improvement to existing methods is that this algorithm can be applied in (partial) weight 1, which fills the gap left by standard computational methods. Moreover, the algorithm computes in all characteristics simultaneously. More precisely, we prove that, under certain conditions in higher weight, the output of the algorithm for given level N and quadratic character E includes a finite set of primes L such that all Hilbert modular forms of given parallel weight, level N and quadratic character E over F p are liftable for all primes p outside the set L. In particular, testing primes in the set L enabled the computation of examples of non-liftable Hilbert modular forms of weight 1. [less ▲]

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See detailStudent-driven Inquiry-based Science Education in Luxembourg Primary School Contexts
Dombkowski-Wilmes, Sara Elizabeth UL

Doctoral thesis (2017)

This study examined the use of a student-driven inquiry-based science education instructional approach designed specifically to meet the contextualized needs of Luxembourg primary schools. The key issues ... [more ▼]

This study examined the use of a student-driven inquiry-based science education instructional approach designed specifically to meet the contextualized needs of Luxembourg primary schools. The key issues, namely an increasing linguistically diverse student population and limited instructional time for science, were considered in the design of the instructional approach. Drawing on theories of dialogic inquiry, the instructional approach engages students in asking questions and designing investigations to build their science understanding. This interpretive qualitative study utilized a multi-perspective approach to analyse how teachers used the instructional approach in their classrooms and explored two overarching research questions, first, what instructional opportunities does Science Workshop, an inquiry-based student-driven science instructional approach, afford when used in Luxembourg primary classrooms? And second, what does analysis of interactions in these contexts reveal about inquiry-based science instruction in multilingual classrooms? Qualitative methodologies, specifically case studies of classroom implementation, were used to examine the use of the program teachers’ adaptations of the program in their classrooms. Bakhtinian notions of heteroglossia and dialogic pedagogies were used as lenses to examine the instructional opportunities afforded. Interaction analysis was used to examine instruction in a focal classroom when the inquiry-based approach was used. Analyses rooted in sociocultural theoretical frameworks of science and language learning revealed three key contributions toward the use of IBSE in Luxembourg primary schools. First, the key characteristics of teacher professional learning opportunities that supported teachers’ use of the program in Luxembourg, which included workshops, material support, and opportunities to share implementation cases were identified. Second, the ways in which ritualized instructional components afford students spaces to engage on micro-scales in building synchronous interactions during science investigations were revealed. Third, that the science notebooks can position students to engage in dialogic discussions surrounding science investigations was shown through detailed analysis. Taken together, these interrelated points contribute to an understanding of the use of student-driven instructional approaches in multilingual science classrooms in general, while revealing implications for the use of inquiry-based science instructional approaches in Luxembourg primary schools specifically. [less ▲]

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See detailDynamic Career Attitudes And Life Satisfaction Among CEDIES' Postgraduates From Luxembourg
Karavdic, Senad UL

Doctoral thesis (2017)

Introduction: With an ever increasing number of university students and the employment shift from an opportunity to insecure development, new postgraduate generations have to be amenable to continuous ... [more ▼]

Introduction: With an ever increasing number of university students and the employment shift from an opportunity to insecure development, new postgraduate generations have to be amenable to continuous upgrading, complete with a wide range of skills in the promotion of their career development. Keeping in mind that the job market and work environment are variables that are mostly changing, the possession of an active career attitude may be a guarantee for postgraduates’ employability and their career outcome. Giving importance to the adjustment during the transitional period, life satisfaction (LS) may be altered based on the discrepancy between career aspiration and career achievement. Among university postgraduates, the main objectives of our doctoral work are to (1) measure the associations between dynamic career attitudes (DCA), generic employment capabilities and socioeconomic factors (2) determine the underlying structure of DCA, protean career orientation and career goal (3) analyze relations between DCA dimensions and career factors such as career goals, protean career orientation and LS (4) evaluate the effects of DCA dimensions on LS for native and non-native Luxembourgish postgraduates. Method: A survey was conducted among 2800 participants registered at the Centre for Documentation and Information on Higher Education (CEDIES). Data collection was realized via an information flyer that was sent to the home addresses of the postgraduates and that contained instructions about the aims of the study and a link to the survey. The postgraduates could directly access the anonymous online questionnaire in either French or English. To explore the associations and relations between variables student t-tests and bivariate correlations were used. Exploratory factor analysis was conducted to identify the underlying relationships between measured DCA dimensions, protean career orientation and career goals. In order to determine the statistical significance of the indirect effect for the mediation analysis, the bootstrapped confidence interval on 1000 bootstrap samples was used. A multiple logistic regression was applied to each group, but only significant variables (p<0.05) were introduced into the regression models. Results: A total of 644 volunteers completed the self-assessment questionnaire online. Majority of the participants were female, students and not employed. Postgraduates with high employment capabilities tend to present a higher dynamic career score that has been identified as a construct of four career dimensions (career adaptability, career optimism, career related knowledge and career planning). Each dimension was mediated from self-directed career dimension of protean career orientation by intrinsic career goal. Career adaptability and career optimism predicted both, happiness and LS. However, this relationship seems only to be presented for ‘postgraduates that are still studying. In the same vein, the DCA dimension of career optimism has been associated to LS by native Luxembourgers, whereas perceived financial situation intervenes in explanation of LS by non-native postgraduates. Discussion and Conclusion: The Dynamic Career Attitudes scale appears to be a relevant instrument in evaluating disparities in employment capabilities among postgraduates. Our findings indicated the application of intrinsic career goal in the development of career attitudes, where career adaptability and career optimism explained the highest proportion of the variance related to LS. The acquisition of qualitative information on DCA from a comparable population at different stages (from career goals aspirations and the process toward career goal accomplishments), could be rendered more straightforward for future research. Finally, it could be interesting to assess the DCA of university graduates during and after their Master’s degrees; before they start work and in the early years of their careers. Contextualizing our findings, the differences of native Luxembourgish and non-native postgraduates don't differ in LS, however, it seems to be influenced by different variables such as financial situation suggesting the introduction of the social grant of CEDIES for the most disadvantaged students. Practical implications are also suggested. Promoting programs proposed by University services towards counseling and an accompaniment to their career attitudes may enhance postgraduates’ LS which are major indicators for a successful mobility. [less ▲]

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See detailArbeiten unter Hitler. NS-Sozialpolitik und Herrschaftspraxis im besetzten Luxemburg 1940-1944
Schoentgen, Marc Mike Claude UL

Doctoral thesis (2017)

Die Arbeit untersucht Grundlagen, Konzeptionen und Auswirkungen der nationalsozialistischen Besatzungsherrschaft in Luxemburg (1940-1944) in den Bereichen der Wirtschafts- und Sozialpolitik ... [more ▼]

Die Arbeit untersucht Grundlagen, Konzeptionen und Auswirkungen der nationalsozialistischen Besatzungsherrschaft in Luxemburg (1940-1944) in den Bereichen der Wirtschafts- und Sozialpolitik. Berücksichtigung findet auch die NS-Volkstums- und Kulturpolitik. Staatliche Maßnahmen führten in der Besatzungszeit dazu, dass während einer relativ langen Phase die Auswirkungen des Krieges auf das Alltags- und Arbeitsleben wenig spürbar waren. Damit trug die Sozialpolitik zu einer politischen und psychologischen Stabilisierung des Regimes bei. Besonders betroffen von der Politik des nationalsozialistischen Gauleiters Gustav Simon waren die Luxemburger Gewerkschaften, die von den Machthabern instrumentalisiert und anschließend liquidiert wurden. An ihre Stelle trat die Deutsche Arbeitsfront, größte Massenorganisation des Regimes, die ihre vielfältigen Aktivitäten in den Bereichen der Sozial-, Wirtschafts-, Freizeit- und Kulturpolitik auch auf Luxemburg ausdehnte. Genauer untersucht wird die Institution des Stillhaltekommissars für das Organisationswesen, der die Gewerkschaften und andere Vereine liquidierte beziehungsweise nazifizierte. Damit wurden die Fundamente der Luxemburger Gesellschaft in Frage gestellt. Die Neuordnungspolitik des Regimes wird u.a. am Beispiel des Industriegebiets im Süden Luxemburgs dargestellt. Im Arbeitermilieu sahen die nationalsozialistischen Machthaber ein Experimentierfeld ihrer Politik. Krieg und Besatzung hatten letztlich auch Auswirkungen auf die großen Industriebetriebe. Gerade hier änderte sich ab der zweiten Hälfte des Krieges durch unterschiedliche Formen der Repression und Zwangsarbeit der Alltag der Menschen. Übergreifend befasst sich die Arbeit auch mit der Luxemburger Kriegsgesellschaft beziehungsweise den unterschiedlichen Reaktionen der Arbeiter und Angestellten auf Verlockung und Zwang. Kapitel: 1. Die NS-Sozialpolitik in Luxemburg 2. Die Luxemburger Gewerkschaften im Krieg. 3. Das Luxemburger Industriegebiet 4. Der Stillhaltekommissar für das Organisationswesen 5. Die Deutsche Arbeitsfront 6. Arbeiten im Krieg [less ▲]

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See detailAspekte der luxemburgischen Syntax
Döhmer, Caroline Elisabeth UL

Doctoral thesis (2017)

Das Ziel dieser Arbeit ist eine empirische und systematische Beschreibung ausgewählter syntaktischer Phänomene im Luxemburgischen. Im Vordergrund der deskriptiven Analyse stehen vier Themenbereiche ... [more ▼]

Das Ziel dieser Arbeit ist eine empirische und systematische Beschreibung ausgewählter syntaktischer Phänomene im Luxemburgischen. Im Vordergrund der deskriptiven Analyse stehen vier Themenbereiche: Kasussyntax und -funktionen (Genitiv, Possession, Partitiv), Pronominalsyntax (Syntax und Semantik von Personalpronomen), Verbcluster (2-, 3- und 4-gliedrige Cluster im Nebensatz) sowie die syntaktischen Eigenschaften von Nebensatzeinleitungen (Kongruenz und Verdopplungen). Die Arbeit soll einerseits dazu beitragen, die luxemburgische Sprache in ihren strukturellen Eigenschaften besser verstehen zu können und andererseits die (syntaktische) Erschließung des Kontinentalwestgermanischen weiter voranbringen. Somit liefert diese Dissertation einen wichtigen Beitrag in der derzeit aufblühenden Forschungsrichtung der linguistischen Luxemburgistik und ordnet sich gleichzeitig in die allgemeine westgermanische Syntaxforschung ein. [less ▲]

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See detailComparative study of reduced-order methods for geometrically nonlinear structures
Khurshudyan, Amalya UL

Doctoral thesis (2017)

The dissertation is devoted to the comparison and development of techniques for model order reduction (MOR) of geometrically nonlinear elastic structures in the static limit. The MOR procedure works in ... [more ▼]

The dissertation is devoted to the comparison and development of techniques for model order reduction (MOR) of geometrically nonlinear elastic structures in the static limit. The MOR procedure works in the following way: the structure is first discretized into finite elements and a discretized system of algebraic equations is obtained, in which the stiffness matrix depends on the unknown vector. The system is then projected to a lower order space. The choice of the basis of the projection space is made according to the methods developed in the thesis. To this end, three techniques are developed here based on different choices of the basis functions. Comparative analysis of the suggested methods is carried out in the case of two-dimensional structures (Euler-Bernoulli beam, multi-span beam and frame). In order to be able to compare the results with those obtained by the MOR techniques which are developed, the benchmark problems which are examined are first solved analytically. Results of computations carried out in Python and are then discussed. [less ▲]

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See detailVERHALTEN AUSGEWÄHLTER NANOPARTIKEL IN KOMMUNALEN KLÄRANLAGEN UNTER BESONDERER BERÜCKSICHTIGUNG DER ANAEROBEN SCHLAMMBEHANDLUNG
Rahimi, Anahita Bahareh UL

Doctoral thesis (2017)

The increasing use of nanoparticles and the market to commercialize this innovative technology requires a deeper understanding of the behavior of nanoparticles (NPs) and the resulting consequences in an ... [more ▼]

The increasing use of nanoparticles and the market to commercialize this innovative technology requires a deeper understanding of the behavior of nanoparticles (NPs) and the resulting consequences in an environmentally The increasing use of nanoparticles and the market to commercialize this innovative technology requires a deeper understanding of the behavior of nanoparticles (NPs) and the resulting consequences in an environmentally relevant matrix. However, since the fate and behavior of nanoparticles is largely unknown to the environment, this study was done to investigate the key properties of nanoparticles, parameters to describe them and to discuss how these parameters can influence their fate and behavior in the natural environment. The core goal of this discussion is to relate sludge treatment to relevant properties of the nanoparticle, which may interact with a range of substances naturally present in wastewater treatment plants (WWTPs) and activated sludge. Understanding these properties is necessary for interpreting the fate of nanoparticles and predicting their effects in the actual environment. Environmentally matrix are challenging to investigate, for instance as in sludge and anaerobic sludge stabilization. According to the literature, it will be assumed that about 95% of the NPs entering the WWTP end up in the sludge. This work reports on the investigation and observation of NPs behavior in the different stages, using different experiments and metering devices. The different experiments include (i) characterization of NPs before their application (NanoSight), (ii) behavior analysis in terms of kinetic transformations (Turbiscan), (iii) long- and short-term analysis of NPs effects on anaerobic sludge stabilization (laboratory fermentation plants). The characterization represents the current size distribution of the NPs in a controlled environment (H2O). Size is one of the defining properties of NPs, which causes changes in physical and chemical properties of NPs compared to their original materials. The results show that the distribution of NPs depends on the type of particle, surface coating and dispersion concentration. These parameters are subject to permanent changes in sludge. That is why an exact allocation to the effects seems almost impossible. Characterization is indispensable for the subsequent comprehension of the effects, and for the understanding of findings, which may result from the behavioral analysis, as well as from the effect analysis. The behavioral analysis was carried out by Turbiscan technology to consider relevant sludge parameters and substances (Chemical Oxygen Demand COD, Polymers, Humic acids, digestion process) to the behavior of NPs in sludge. The initial aim was to progressively add of representative substances to approximate the experiment to natural conditions. The phase separation detection identified a clear sedimentation behavior in all samples. To explain this and the kinetic modification as well as the resultant kinetic instability, the NPs’ diameter (particle size detection) were studied. The more instable samples had often smaller diameters. The substances within the sludge seem to influence the kinetic stability of NPs. This could be caused by the dynamic corona (active interaction with environment) and hard corona (strongly bound and restrained interaction with environment) formation, as well as agglomeration or modification of surface charges. Changes in kinetic stability means changes in the behavior and fate of NPs in such an environmental media like sludge. However, since the sludge is filtered for the behavioral analysis, the microorganism’s role is neglected. In order to complete the behavioral analysis considering the microorganism’s contribution, the consequences of the NP-behavior are measured as effects under various realistic conditions. The effects of NPs’ behavior on the anaerobic microorganisms were investigated based on their potential and efficiency in anaerobic sludge stabilization for gaining additional insights. The long-term effects of NPs in sludge treatment plants (STP) were investigated using four parallel pilot reactors operated under identical conditions, with daily feeding (substrate and two different NP-concentration). There was a temporary decrease of Biogas especially at the third phase (second concentration) except for the ZnO-reactor while the proportion of methane remained stable. Based on the knowledge obtained from the characterization and behavioral analysis, this might be due to the kinetic transformation of NPs. When the particle size for instability is exceeded as a consequence of surface changes and agglomerations, rapid sedimentation occurs. After eliminating the NP-reactivity and obtaining NP-agglomerations, NPs are extracted from the digestion system (sedimentation). Due to that, the microorganisms are able to operate to their full potential and efficiency, which is an indication of extracellular inhibition and preclude probably the intracellular inhibition caused by ions release. The short-term effects of ENPs in batch experiments were investigated under identical conditions. Furthermore, oxygen was used as an inhibitor to intensify the NP’s effects on the anaerobic microorganisms and digestion process. Oxygen is toxic for anaerobic microorganisms and enhance the release of ions. NP-effects were evaluated for methane yield. It will be assumed that the corona formations created by the sludge substances, reduce the release of ions and the NP-toxicity, even after decreasing the biomass. In addition, the NPs are able to eliminate O2 as an inhibitor, as well as positively influence the production dynamics and methane yield. To sum up, the growing interest in nanoparticles and their potential has presented many challenges for science, in toxicology and innovative technologies. These challenges bring new questions related to understanding NPs and their interplay with certain circumstances. A considerable contribution has been made for understanding the behavior of nanoparticles in the environmentally relevant media. However, a partial understanding for the fate of nanoparticles in complex matrices has been gained. As the nanoparticles themselves are such a complex matter, they require more research in developing a more complete understanding of the way they function. Having this knowledge would enable to explore progressively their behavior and fate in complex matrices.. [less ▲]

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See detailSecond language learners’ self-initiated topic changes during book-related activities in preschool and their impact on Luxembourgish proficiency
Wirtz, Delia UL

Doctoral thesis (2017)

The present research traces the second language learning process in Luxembourgish during book related activities by 4- to 5-year old pre-schoolers with Portuguese, Cap Verdean and Brazilian origins. With ... [more ▼]

The present research traces the second language learning process in Luxembourgish during book related activities by 4- to 5-year old pre-schoolers with Portuguese, Cap Verdean and Brazilian origins. With 47,2% of the preschool population being of foreign origins, the Lusophone community forms the largest group with 24,1%. This salient fast growing multilingual and multicultural population learns Luxembourgish for integration and everyday interaction and, hence, challenges public education with its diverse and altering demands. The present study enlarges second language research in the Luxembourgish context and links to previous investigation on topics, however, by taking a pragmatic stance towards topics. Through the foregrounding of the local topic management as well as its impact on activities, which are less teacher controlled, the study pictures second language learning as a product of co-constructed interaction. The focus lies on the negotiation of story meaning through self-initiated topic changes during three book related activities: Joint reading, storytelling and play. The data consists of video recorded lessons and on stimulated recall interviews with the teachers. A multi-method framework is used to investigate pupils’ interaction and language learning processes. From a quantitative point of view, the study analyses how pupils’ utterance length varies according to the openness of the lesson by allowing self-initiated topic changes as well as the design of the book activity (1) led by teachers or (2) by the pupils. From a qualitative stance, a sequence-by-sequence analysis of the jointly constructed narrative identifies the interactional dynamics of the collaborative storytelling activities and the use of self-initiated topic changes which children draw upon to express themselves more freely. The results show that children’s utterances vary according to the activity type. Pupils produce longer utterances, when they can self-initiate a topic hereby boosting their second language proficiency – either because the teacher is withdrawing or because the participation framework is open enough for them to make creative use of the language. The children also show their capability of successfully managing topic changes without the presence of the teacher while at the same time co-constructing the meaning of the story and paying attention to lexical details. The interviews reveal the teachers’ astonishment for the degree of pupil participation as well as their pedagogical practices. Implications from the analysis are gathered in a theoretical model that links opportunities for self-initiated topic changes to language proficiency. Recommendations for a more active pupil participation during book related activities point to sense-making, joint topic negotiation and story enactment. [less ▲]

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See detailCryptanalysis, Reverse-Engineering and Design of Symmetric Cryptographic Algorithms
Perrin, Léo Paul UL

Doctoral thesis (2017)

In this thesis, I present the research I did with my co-authors on several aspects of symmetric cryptography from May 2013 to December 2016, that is, when I was a PhD student at the university of ... [more ▼]

In this thesis, I present the research I did with my co-authors on several aspects of symmetric cryptography from May 2013 to December 2016, that is, when I was a PhD student at the university of Luxembourg under the supervision of Alex Biryukov. My research has spanned three different areas of symmetric cryptography. In Part I of this thesis, I present my work on lightweight cryptography. This field of study investigates the cryptographic algorithms that are suitable for very constrained devices with little computing power such as RFID tags and small embedded processors such as those used in sensor networks. Many such algorithms have been proposed recently, as evidenced by the survey I co-authored on this topic. I present this survey along with attacks against three of those algorithms, namely GLUON, PRINCE and TWINE. I also introduce a new lightweight block cipher called SPARX which was designed using a new method to justify its security: the Long Trail Strategy. Part II is devoted to S-Box reverse-engineering, a field of study investigating the methods recovering the hidden structure or the design criteria used to build an S-Box. I co-invented several such methods: a statistical analysis of the differential and linear properties which was applied successfully to the S-Box of the NSA block cipher Skipjack, a structural attack against Feistel networks called the yoyo game and the TU-decomposition. This last technique allowed us to decompose the S-Box of the last Russian standard block cipher and hash function as well as the only known solution to the APN problem, a long-standing open question in mathematics. Finally, Part III presents a unifying view of several fields of symmetric cryptography by interpreting them as purposefully hard. Indeed, several cryptographic algorithms are designed so as to maximize the code size, RAM consumption or time taken by their implementations. By providing a unique framework describing all such design goals, we could design modes of operations for building any symmetric primitive with any form of hardness by combining secure cryptographic building blocks with simple functions with the desired form of hardness called plugs. Alex Biryukov and I also showed that it is possible to build plugs with an asymmetric hardness whereby the knowledge of a secret key allows the privileged user to bypass the hardness of the primitive. [less ▲]

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See detailWelche Organisationsformen produzieren Wissenschaft? Expansion, Vielfalt und Kooperation im deutschen Hochschul- und Wissenschaftssystem im globalen Kontext, 1900-2010
Dusdal, Jennifer UL

Doctoral thesis (2017)

Overview and introduction “Which organizational forms produce science? Expansion, diversity, and cooperation in Germany's higher education and science system embedded within the global context, 1900-2010” ... [more ▼]

Overview and introduction “Which organizational forms produce science? Expansion, diversity, and cooperation in Germany's higher education and science system embedded within the global context, 1900-2010”. Already the title of my dissertation manifests an approach that examines the topic of the development of scientific productivity in the German higher education and science landscape from different perspectives: levels, dimensions, and an extensive timeframe. Deriving from and contributing to the international research project “Science Productivity, Higher Education, Research and Development, and the Knowledge Society” (SPHERE), my research focuses on the investigation of the influence of higher education development and science capacity-building on scientific knowledge production, globally, comparatively, and considerable depth for Germany, a key science producer for well over a century. Focusing mainly on the different structures and institutional settings of the German higher education and science system, the dissertations shows how these affected and contributed to the long-term development of scientific productivity worldwide. The historical, comparative, and in-depth analyses are especially important in light of advancing globalization and internationalization of science, stronger networks of scientists worldwide, and the emergence of the “knowledge society”. The research design combines macro- and meso-level analyses: the institutionalized and organizational settings in which science is produced. Since information about single authors was limited in availability, extensive micro-level analyses were not possible here, yet the research articles analyzed were all written and published by individuals working in organizations, which are in the center of analysis here. By reference to the dimensions expansion, diversity, and cooperation, I elaborated the frame of my investigation, and sorted my research questions, including country, organizational field and form, and organizational levels. The structure of this work (see outline) addresses these themes and the observed timeframe spans the years from 1900 to 2010 – more than a century (see section 1.2). My main goal was to investigate how and why scientists publish their research results in peer-reviewed journal articles. The point is to emphasize the importance of scientific findings/discoveries, because non-published results are non-existent for the scientific community. From the ways and in which formats scientists publish their work, we can deduce how science is organized (within and across disciplines). My dissertation analyzes publications in peer-reviewed journals, because they are the most important format – alongside patents in applied fields – to disseminate new knowledge in science, technology, engineering, mathematics, and health (hereafter STEM+ fields). Articles not only record new knowledge, but also contribute to the reputation of researchers and their organizations. Journal publications in reputable journals with peer-review have become the “gold standard” measure of scientific productivity. Within the last several decades, the scientization of many dimensions of societal life proceeded, and the generation of new knowledge increasingly became the focus of political, economic, and social interests – and research policymaking. Therefore, it is important to identify the institutionalized settings (organizations/organizational forms) in which science can best be produced. Here, the diverse types of organizations that produce science – mainly universities, research institutes, companies, government agencies and hospitals – were identified and differences and similarities of these organizational forms were analyzed on the basis of their character, goals, tasks, and the kinds of research their members produce. In a first step, I show why I structured my work at the interface of higher education research, science studies, and bibliometrics (see chapters 2 and 5). Analyzing publications is still the key task of bibliometrics, but the results are used by many other actors as well: higher education managers, politicians, and scientists themselves to make claims about the quality of science, to compare each other, or to influence the structure, organization, and output of the higher education and science system. While it is difficult to make direct statements about the quality of research on the basis of simply counting the number of research articles a scientist publishes, the quality of journals is used as a proxy to compare across disciplines. To measure quality, other parameters are necessary. Thus, here statements focus on the quantity of science produced, not on the intrinsic quality of the analyzed research articles, the specific research achievements of individual scholars, organizations or organizational forms, or even countries. Nevertheless, output indicators elaborated here definitely show the huge expansion of scientific production and productivity, the stability of the research university over time as the most important science producer in Germany, but also rising differentiation and diversification of the organizational forms contributing to overall scientific output. Furthermore, the start of a considerable and on-going rise in national and international collaborations can be dated to the early 1990s. The chapter about the multidisciplinary context (see chapter 2) discusses the relationship between higher education research and science studies in Germany as well as the special position of scientific knowledge in comparison to other forms of knowledge. Scientific knowledge is generated, distributed, and consumed by the scientific community. To get an overview about the most important studies in the field, and to contextualize my work within the already existing empirical studies, I describe the current state of research in chapter 3. Research questions Section 1.2 provides a detailed description of my research questions: Which organizational forms produce science? 1. How has worldwide and European scientific productivity developed between 1900 and 2010 in comparison? 2. How has the German higher education and science system been embedded in the global developments of higher education and science over time? 3. How has scientific productivity in Germany developed between 1900 and 2010? 4. Among all science-producing organizational forms, what do the key organizational forms contribute to scientific productivity? 5. Which organizational forms provide the best conditions for scientific productivity? 6. Which single organizations produce the most research in Germany? 7. What is the impact of increasing internationalization of research on national and international cooperation, measured in publications in scientific journals? Theoretical framework Theoretically (see chapter 4), I apply a neo-institutional (NI) framework to explore and explain both the tremendous expansion of higher education and science across the world and considerable differences across time and space in the institutional settings, organizational forms, and organizations that produce scientific research in Germany. Sociological NI focuses on understanding institutions as important in guiding social action and shaping processes of social development. Such an approach emphasizes the development, functioning, and principles of institutions. Milestones in NI describe the nexus of organization and society supposing that organizational structures express myths and reflect ideals institutionalized in their environment. While capturing, copying, and asserting these, structural similarity (institutional isomorphism) between organizations in society will be established. The concept of “organizational field” emphasizes relationships between organizations within an environment. Organizational fields (communities) consist of all relevant organizations. In section 4.1.2 I discuss the differences between institutions and organizations and the difficulty of a distinction of the terms, especially in German-speaking sociology, which does not distinguish clearly between these terms. Fundamentally, NI approaches differ in the dimensions or pillars and levels of analysis they privilege (see figure 5, p. 80), but they share fundamental principles and the theoretical framework. Thus NI is particularly suitable for a multi-level analysis of scientific productivity across time and space. The historical development of the German higher education and science system must analyzed considering also global developments, because on the one hand it had an enormous impact on the development of other systems worldwide, and, on the other hand, global trends affect the on-going institutionalization and organization(s) of science in Germany. Intersectoral and international cooperation is growing and becoming increasingly important, leading to diverse networks within and between higher education and science systems worldwide. The classical, national case study is hardly longer possible, because macro units like countries are highly interdependent, embedded in global, regional and local relationships, such that borders between the global and the national dimension are increasingly blurred. Nevertheless, countries are units with clearly defined boundaries and structures, thus they can be handled as units to compare. The theoretical perspectives and different levels of analysis addressed here are displayed in Figure 5. I apply the “world polity” approach as a broader lense with which to make sense of the truly global arena of higher education and science (macro level). The focus of this perspective is on global and international structures and processes, which developed over time. Through this perspective, I explore global diffusion and formal structures of formal principles and practical applications. Combining historical and sociological institutionalism helps to focus on developments and processes over time on the meso level, to explain how institutions have developed and change(d). The concepts of “critical junctures” and path dependencies are useful to explain these processes over time. To describe the transformation of knowledge production over the entire twentieth century, and to analyze different organizational forms that produce science in Germany, two prevalent theoretical concepts are discussed: Mode 1 versus Mode 2 science, and the Triple-Helix model to describe the relationship between science, industry and state. In “The New Production of Knowledge” Michael Gibbons and his colleagues describe the transformation of knowledge from an academic, disciplinary, and autonomous – “traditional” – organization of science (Mode 1) with a focus on universities as the key organizational form, to a more applied, transdisciplinary, diverse, and reflexive organization of science (Mode 2) that features a more diverse organization of science, relying on a broader set of organizations producing knowledge. Within the literature, debates center on whether this new model has replaced the old, and which of these models best describes the contemporary organization of science (here: the STEM+ fields). In turn, the Triple-Helix model preserves the historical importance of the universities. This approach assumes that future innovations emerge from a relationship between universities (production of new knowledge), industry (generation of wealth), and state (control). Data and methods In these analyses, only peer reviewed journal publications were used – as the best indicator for measuring the most legitimated, authoritative produced science. This focus enabled an investigation of publications in-depth and over a 110 year timeframe. Research articles in the most reputable, peer-reviewed, and internationally reputable journals are the gold standard of scientific output in STEM+. The data I used is based on a stratified representative sample of published research articles in journals in STEM+-fields. My measure relies on the key global source for such data, the raw data from Thomson Reuters’ Web of Science Science Citation Index Expanded (SCIE) (the other global database is Elsevier’s Scopus, which also indexes tens of thousands of journals), which was extensively recoded. Methodologically, my approach is based on a combination of comparative institutional analysis across selected countries and historically of the German higher education and science system, and the systematic global evaluation of bibliometric publication data (see chapter 6). The SCIE includes more than 90 million entries (all types of research), mainly from STEM+-fields. I focus on original research articles, because this type of publication contains certified new knowledge. The SPHERE dataset covers published research articles from 1900 to 2010. From 1900 to 1970, we selected data in 5-year-steps in the form of a stratified representative sample. From 1975 onwards full data is available for every year. Depending on the research question, either five or ten-year steps were analyzed. A detailed description of the sampling and weighting of the data can be found in chapter 6. In consideration of the criteria above, I analyzed 17,568 different journals (42,963 journals were included into the database if we count the same journals in different years), and a total of 5,089,233 research articles. To prepare the data for this research, it had to be extensively cleaned and coded. Very often our international research team found missing information on the country level and/or on the level of organizations/organizational forms. From June 2013 to December 2015, research in the archives of university libraries was necessary to manually add missing information, particularly organization location and author affiliations. In the field of bibliometrics, we find different methods to count publications. In this work, I mainly apply the “whole count” approach (see table 1, p. 126). This decision is based on the assumption that every author, organization, or country contributed equally to a publication. An overestimation of publications can’t be precluded, because research articles are counted multiple times, if a paper is produced in co-authorship, which has been rising worldwide over the past several decades. The absolute number of publications (worldwide, Europe, Germany) is based on a simple counting of research articles (without duplicates, in cases of co-authored articles). Summary of the most important results The empirical part of my work is divided into three parts. In the following sections, I will present the most important findings. The global picture – higher education and science systems in comparison The central question of my research project was “which organizational forms produce science”? For a better understanding and classification of the results of my case study, I embedded the German higher education and science system into the European and global context. I answered the questions “how did the worldwide and European scientific productivity developed between 1900 and 2010 in comparison”, and “how was/is the German higher education and science system embedded in global developments of higher education and science over time” as follows: First, I show that the worldwide scientific growth followed a pure exponential curve between 1900 and 2010 (see figures 3 and 10; pp. 50, 147) – and we can assume that this strong upward trend continues today. The massive expansion of scientific production had and still has a tremendous influence on societal developments, beyond simply economic and technical developments, but rather transforming society. I show that higher education and science systems worldwide exhibit communalities, which have led to similar developments and expansion of scientific productivity. The comparison of important European countries (Germany in comparison with Great Britain, France, Belgium and Luxembourg) uncovered the contribution of the development and spread of modern research universities and the extraordinary and continued rise in publication output (see section 7.2; Powell, Dusdal 2016, 2017a, 2017b in press). Within the global field of science, three geographical centers of scientific productivity have emerged over the twentieth century: Europe, North America, and Asia. Their relative importance fluctuates over time, but today all three centers continue to be the key regions in the production of scientific research in STEM+ journals. Especially in Asia, the growth rates have risen massively in recent years (Powell et al. 2017 in press). Second, I investigated that all countries worldwide invest more into research and development (R&D) (figure 9, p. 140). These investments have a clear impact on the scientific productivity of nations, yet there are important differences between countries in absolute production and productivity rates. Alongside direct investments in R&D or the application of patents in STEM+-fields that influence the expansion of science, the capacity for producing more knowledge fundamentally depends on rising student enrolments, a growing number of researchers, the widening of research activities into various arenas of society, the development of products, and the (re-)foundation of universities (Powell, Baker, Fernandez 2017 in press). As part of the higher education expansion and massification during the 1960s and 70s, the numbers of researchers and students rose tremendously. The growth of scientific publications thus results from the on-going institutionalization of higher education and science systems worldwide. The growth of publications is also explained by the steady growth in the number of researchers working within these growing – and increasingly interconnected – systems. Third, I could reject the argument of Derek J. de Solla Price that the pure exponential growth of scientific literature has to flatten or would slow-down several decades after the advent of “big science” (see paragraph 2.4; figure 4 and 10; p. 53, 147). Although radical historical, political, economical, and technical events (see figure 11, p. 150) led to punctual short-term decreases in publication outputs, the long-term development of universities and other organizational forms producing science led to sustained growth of scientific publications, with the numbers of publications rising unchecked over the long twentieth century. In 2010, the worldwide scientific productivity in leading STEM+ journals was about one million articles annually. Fourth, I could show that the absolute numbers have to be put into perspective and standardized in relation to the investments in R&D, the size of the higher education and science systems, the number of inhabitants (see figure 12, p. 159), and the number of researchers (table 3, p. 162; figure 13, p. 164). The initial expansion of scientific publications in STEM+-fields is based on a general growth of higher education and science systems. The different institutional settings and organizational forms that produce science have an impact on scientific productivity. The selected country case studies – Germany, Great Britain, France, Belgium and Luxembourg – demonstrate that systems with strong research universities are highly productive; they seem to provide conditions necessary for science. As a result, not only the number and quality of researchers is important, but also the institutional and organizational settings in which they are employed. Fifth, in international comparison, Germany continues to contribute significantly to scientific productivity in STEM+ fields. With an annual growth rate of 3.35%, Germany follows the United States and Japan. In 2014, German governments invested €84.5 billion in R&D – 2.9% of overall GDP. The EU-target of 3% by 2020 was barely missed. In 2010, Germany produced 55,009 research articles (see table A5). In comparison to Great Britain, France, Belgium and Luxemburg, Germany still leads in scientific output in Europe –comparing just the absolute numbers. The size of the country itself and the institutionalization of the higher education and science systems influence publication outputs, of course, with these absolute numbers in relation to other key indicators showing a different picture. Standardized by the number of inhabitants, Germany published less articles per capita than Belgium and Great Britain. The number of researchers amounted to 327,997 (FTE) in 2010. The ratio of inhabitants to scientists was 1,000:4. Among these countries studied in-depth, Luxembourg and Great Britain had more researchers per capita than did Germany. The interplay of the organizational forms of science in Germany between 1900 and 2010 On the basis of the analysis of the global and European contexts, and development of worldwide scientific productivity over time in chapter 7, I started the in-depth case study of Germany. Bridging this overview and the following in-depth analyses is a chapter on the institutionalization of the German higher education and science system (see chapter 8). Here, I described the most important institutions and organizations and the organizational field – universities, extra-university research institutes and universities of applied sciences. Furthermore, I discussed the differences between West and East Germany during their division (1945–1990). Summarizing the most important results shows that the development of publications in Germany follows global and European trends (on a lower scale) (see figure 16, p. 208). Over time, Germany experienced pure exponential growth of scientific publications and a rising diversity of organizational forms that contribute to scientific productivity (see sections 9.1 and 9.3). I answered the following three research questions: “how has the scientific productivity in Germany developed between 1900 and 2010”, “among all science producing organizational forms, what do the key organizational forms contribute to scientific productivity”, “which organizational forms provide the best conditions for scientific productivity”, and “which single organizations are the most research intense in Germany”? First, the growth curve of scientific publications in Germany turns out as expected – it shows pure exponential graph, comparable with the worldwide and European development of scientific productivity between 1900 and 2010. Here, too, cataclysmic events such as the two world wars and the Great Depression as well as reunification had only short-term (negative) impact (figure 11, p. 150) on scientific productivity, without even a medium-term slow-down or flattening of the curve. By 2010, the total number of publications in STEM+ fields by researchers in German organizations topped 55,000 in one year alone. Second, a detailed examination and comparison of the development of scientific productivity in West Germany and East Germany between 1950 and 1990 showed that the growth rate of Germany (altogether) was based mainly on steady growth of scientific publications in West Germany (see figure 17, p. 211). The growth curve of the former GDR was quite flat and proceeded on a very low level. As a result, I conclude that the GDR’s higher education and science system, based on its academy model, did not provide conditions for scientific productivity as optimally as did the BRD. Third, a detailed analysis of the “key classical” organizational forms of science – universities and extra-university research institutes – show that universities were and are the main producers of scientific publications in STEM+ from 1975 to 2010 (see figure 18, p. 217). On average, university-based researchers produced 60% of all articles and defended their status against other organizational forms, which leads to the rejection of the Mode 2 hypothesis. Non-university publications reached an average of 40%. But that does not mean that other organizational forms were not producing science as well. The percentage share of articles is ultrastable and shows only marginal variations. The thesis that the proportion of university publications should decrease over time can be rejected for the period from 1975 to 2010. This suggests that scientific productivity of universities is actually rising, since despite decreasing financial support (R&D) in favor of extra-university research institutes, the universities produced more research articles with less resources over time. Fourth, although not only scientists within universities and research institutes publish their research in scientific journals, jointly these organizational forms have produced more than three-quarters of all research articles since 1980. Already in the earlier years, they produced a large number of scientific articles. Other organizational forms also generate scientific knowledge (for an extensive description of the organizational form matrix, see table 4, pp. 222f.). Especially scientists in firms, government agencies, and hospitals publish articles in peer-reviewed journals in STEM+ (see figures 19 and 20; pp. 220, 246). Indeed, the universities have been the driving force of scientific productivity for more than a century. With their specific orientation to basic research and their linkage of research and teaching, they provide conditions that facilitate the production of science. Universities are among the oldest institutions with a high degree of institutionalization. All other organizational forms (academies, associations, infrastructures, laboratories, military, museums and non-university education) were identified in the dataset played only a minor role and were summarized in the category “further types”. Fifth, the analysis of the ten most research-intensive single organizations in Germany in the year 2010 confirmed the results. Only universities and institutes were part of this group. A summary of publications of single institutes under their umbrella organizations shows that the institutes of the Max Planck Society and of the Helmholtz Association are the leading science producers in Germany, outpacing the scientific productivity of universities, but only when aggregating the contributions of dozens of individual institutes (see table 5, p. 259f). An analysis of single institutes shows that these research institutes cannot compete with universities, because of their size and the number of researchers. The Charite – Universitätsmedizin Berlin, a hybrid organization, is another leading science producer in Germany. National and international cooperation of scientific research Finally, increasing internationalization of research has impacted on national and international cooperation. leading to collaboratively-written publications in scientific journals. Through advancing globalization, national and international scientific cooperation increased in volume and importance. International cooperation in STEM+ is facilitated by the reputation of the research organization and of the co-authors, higher visibility within the scientific community and more possibilities for interdisciplinary research as well as better or more specialized facilities. Today, more than a third of all research articles worldwide are produced in scientific collaboration; only around a quarter are single-authored articles. In contrast to Humboldt’s principle “in Einsamkeit und Freiheit” (in loneliness and freedom), research is no longer done by one scientist, but is much more likely the result of collaboration. Research networks are increasingly important, and researchers share their common interests on a research question, publishing their results in joint publications. Researchers, organizations, and indeed countries differ in the ways they organize their research and thus how they enable research and collaboration. This depends on location, size, higher education and science system, the organizational field and organizations. Here, varying patterns of scientific cooperation were presented, showing a massive increase in scientific collaboration in (inter)national co-authorships over time. Until the 1990s, researchers in all investigated countries (France, Germany, Great Britain, USA, Japan, China, Belgium, Luxembourg) published their research articles mainly as single-authored papers. Only since the 1990s have co- and multi-authored publications risen (considerably): In 2000, only a third of all publications were published by one author. In 2010, the proportion reached its lowest level with only one-fifth of all papers single-authored (see table 6, pp. 279f). Countries differ considerably in their amount of collaboratively-written research articles. References Powell, J. J. W. & Dusdal, J. (2016). Europe’s Center of Science: Science Productivity in Belgium, France, Germany, and Luxembourg. EuropeNow, 1(1). http://www.europenowjournal.org/2016/11/30/europes-center-of-science-science-productivity-in-belgium-france-germany-and-luxembourg/. Last access: 13.12.2016. Powell, J. J. W. & Dusdal, J. (2017a): Measuring Research Organizations’ Contributions to Science Productivity in Science, Technology, Engineering and Math in Germany, France, Belgium, and Luxembourg. Minerva, (). Online first. DOI: 10.1007/s11024-017-9327-z. Powell, J. J. W. & Dusdal, J. (2017b in press). The European Center of Science Productivity: Research Universities and Institutes in France, Germany, and the United Kingdom. IN Powell, J. J. W., Baker, D. P. & Fernandez, F. (Hg.) The Century of Science: The Worldwide Triumph of the Research University, International Perspectives on Education and Society Series. Bingley, UK, Emerald Publishing. Powell, J. J. W., Baker, D. P. & Fernandez, F. (2017 in press). The Century of Science: The Worldwide Triumph of the Research University, International Perspectives on Education and Society Series. Bingley, UK, Emerald Publishing. Powell, J. J. W., Fernandez, F., Crist, J. T., Dusdal, J., Zhang, L. & Baker, D. P. (2017 in press). The Worldwide Triumph of the Research University and Globalizing Science. IN Powell, J. W., Baker, D. P. & Fernandez, F. (Hg.) The Century of Science: The Worldwide Triumph of the Research University, International Perspectives on Education and Society Series. Bingley, UK, Emerald Publishing. [less ▲]

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See detailOptinization of wireless energy transfer for mid-range distances
Ripp, Pascal UL

Doctoral thesis (2017)

This thesis deals with the optimization of resonators for wireless power transfer by resonant magnetic coupling, where loosely coupled LC resonators are used for wireless power transmission. While systems ... [more ▼]

This thesis deals with the optimization of resonators for wireless power transfer by resonant magnetic coupling, where loosely coupled LC resonators are used for wireless power transmission. While systems that are currently available use discrete capacitors for frequency tuning, this work proposes self-resonating coils on a printed circuit board. For these coils, different three-dimensional (3D) Computer Aided Design (CAD) models are created and investigated using the method of finite elements. Finally, a set of inductively coupled and capacitively coupled self-resonant coils for the 6.78 MHz ISM band is found. Furthermore, the shielding of the coils with ferrite materials is discussed to maintain a high efficiency for any application. For both types, equivalent circuit models are derived and analyzed. Besides the coil optimization, a power amplifier is also proposed. During operation the optimal operational frequency is maintained by frequency tracking. The theoretical results are verified using a demonstrator circuit. [less ▲]

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See detailDRYING AND CONVERSION ANALYSIS OF BIOMASS BY A DEM-CFD COUPLING APPROACH
Mohseni, Seyedmohammad UL

Doctoral thesis (2017)

Biomass materials as a type of renewable energy sources have attracted many attention nowadays to decrease fossil fuel usage due to ecological and economical benefits. The main objective of this PhD ... [more ▼]

Biomass materials as a type of renewable energy sources have attracted many attention nowadays to decrease fossil fuel usage due to ecological and economical benefits. The main objective of this PhD thesis is studying the drying and conversion of biomass materials with employing a hybrid four-way DEM-CFD coupling approach in which considers the solid particulates as discrete elements coupled via heat, mass and momentum transfer to the surrounding gas as continuous phase. Where a comprehensive three-dimensional numerical model is developed and applied to investigate the complex phenomena taking place during biomass drying and conversion in a reactor. That is referred to take into account the physical and chemical processes as heat-up, drying, pyrolysis, gasification and combustion including the essential heterogeneous and homogeneous reactions which is considered as an interactive solid-gas multiphase system. In the proposed model, the motion and thermodynamic state of the particles are involved with employing the relevant governing equations. Where the conductive and radiative heat transfer between particles as well as convective heat transfer between particles and gas phase are taken into account. In addition, some interfaces are extended for coupling the solid particles and the gas phase to consider the interactions in between. At first, the importance of biomass resources is discussed and then the mathematical modeling employed in the PhD thesis is explained thoroughly. To apply the model, four different cases are assessed where two chapters discuss the drying behavior of biomass particles in two different situations. Afterwards, the motion of solid particles in a bubbling fluidized bed is examined. Finally, the conversion of wood materials in a bubbling fluidized bed is determined. [less ▲]

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See detailDynamic change of the human gastrointestinal microbiome in relation to mucosal barrier effects during chemotherapy and immune ablative intervention
Kaysen, Anne UL

Doctoral thesis (2017)

Numerous studies have demonstrated that the gastrointestinal tract (GIT) microbiota plays important roles for the human host. Since the GIT microbiota interfaces with the immune system and represents a ... [more ▼]

Numerous studies have demonstrated that the gastrointestinal tract (GIT) microbiota plays important roles for the human host. Since the GIT microbiota interfaces with the immune system and represents a first line of defense against infectious agents, interest has grown in whether the GIT microbiota may influence the outcome of different anticancer treatments. In this study, the GIT of pediatric patients with different cancer types as well as adult patients with hematologic malignancies undergoing an allogeneic hematopoietic stem cell transplantation were sampled throughout their treatment. In order to deeply profile not only the composition of the community, but also the functional capacity and expression, recently developed wet- and dry-lab methodologies for integrated multi-omic analyses were applied. The trajectories of the prokaryotic and microeukaryotic GIT communities of the patients were described in detail using 16S, 18S rRNA gene amplicon sequencing, as well as metagenomic and metatranscriptomic shotgun sequencing. Indeed, changes in the GIT microbiome in response to treatment were detected. Some changes that are generally thought to be detrimental for human health were detected during treatment, such as a decrease in alpha-diversity, a decrease in relative abundance of bacteria associated with health-promoting properties (such as Blautia spp., Roseburia spp. and Faecalibacterium spp.), as well as an increase in the relative abundance of antibiotic resistance genes. These changes were more pronounced in the adult hematology patients than in the pediatric patients, which is likely due to the more intensive treatment. Some observations need further investigation in order to explain their implication in human health. For example, in the pediatric patients, lower relative abundance of Akkermansia muciniphila was associated with mucositis and functional gene categories that are linked to bacteriophages or the bacterial defense mechanism against bacteriophages were associated with the overall status of the patient and mucositis development. Importantly, in both cohorts, high inter-individual but also high intra-individual variation in the prokaryotic communities were detected while the microeukaryotic community did not exhibit drastic changes. In conclusion, the employed integrated multi-omics analysis allowed detailed profiling of the GIT community including archaea, bacteria, eukaryotes and viruses as well as the functional potential including antibiotic resistance genes. In the future, analysis of the individual-specific processes within the GIT microbial community of patients throughout treatment might allow to adjust therapy regimens accordingly and improve the overall outcome of the therapy. [less ▲]

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See detailWhat Dignity Demands: From Political to Poetical Liberalism
Mailey, Richard Samuel David UL

Doctoral thesis (2017)

The thesis attempts to measure the disjoint between the promise of human dignity that appears at the heart of Western law (e.g. in national constitutions and international human rights instruments), and ... [more ▼]

The thesis attempts to measure the disjoint between the promise of human dignity that appears at the heart of Western law (e.g. in national constitutions and international human rights instruments), and the experiences of exclusion and frustration that, in 2017, have seen many Westerners turn to anti-liberal, populist demagogues for relief. In measuring this disjoint, the thesis looks to the work of liberal and anti-liberal theorists alike, including John Rawls, Bruce Ackerman, Carl Schmitt and Jacques Derrida. It then uses the insights gained to construct a liberal theory that can overcome the key problems identified, before using this theory to critically engage with the constitutional jurisprudence of three very different states: Canada, South Africa and the United States. [less ▲]

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See detailInvestigation of the Nuclear Function of Tes, an Actin-Binding LIM Protein and Potential Tumor Suppressor
Vaccaroli, Raffaella UL

Doctoral thesis (2017)

The nucleus and the actin cytoskeleton are two distinct components of the eukaryotic cell. While the actin cytoskeleton is a dynamic structure that confers a high degree of cellular mobility as well as a ... [more ▼]

The nucleus and the actin cytoskeleton are two distinct components of the eukaryotic cell. While the actin cytoskeleton is a dynamic structure that confers a high degree of cellular mobility as well as a connection to the extracellular environment, the nucleus contains the genome and is strongly associated with gene expression from the steps of signal transduction to the actual transcription and the resulting translation. Although both components were initially studied separately, the ever-growing knowledge has lately asserted that they are tightly connected. In line, multitude of actin binding proteins were found to have roles in the nucleus, in addition to their well described roles in the cytoplasm. This research work focuses on the actin cytoskeleton protein Tes and its role in the nucleus. Tes is considered as a tumor suppressor protein, since its expression is reduced in different types of cancer cell lines and primary tumors, while its re-expression inhibits various aspects of cancer progression such as invasiveness and metastasis. As a cytoskeletal protein, Tes has been associated with actin polymerization as well as with cell migration and cell spreading. Our results show that, in addition to its cytoplasmic localization, Tes is localized in the nucleus. Artificial size increase of Tes, using a tag based on multiple GFP proteins, allowed us to assign Tes nuclear import to an active mechanism. Through fluorescence microscopy analysis of different modular fragments of Tes, we demonstrated that its PET and LIM1/2 domains are required for its nuclear localization. We also identified a classical monopartite nuclear localization signal (NLS) harbored within its PET domain, required for Tes import in the nucleus. In addition to Tes nuclear import, we also examined its nuclear export. Using the drug Leptomycin B, we demonstrated that Tes nuclear export is active and dependent on the CRM1-export mechanism. By combining protein sequence analysis with point mutations, we identified and characterized the nuclear export signal (NES) at the N-terminus of Tes. Using a photoconvertible probe, we demonstrated the presence of a slower photoconverted fraction of Tes in the nucleus, compared to the more dynamic cytoplasmic fraction. This prompted us to investigate further the existence of potential nuclear partners of Tes. Quantitative mass spectrometry analysis provided evidence for a potential involvement of Tes in nuclear pathways mediating the remodeling of actin, thus suggesting a novel role for Tes in the reorganization of the nuclear actin cytoskeleton. Furthermore, the proteomics studies associated the nuclear localization of Tes with signaling pathways promoting inflammation and cellular death. These results raised the hypothesis that Tes might promote tumor suppression not only through its cytoplasmic functions, but also through these newly described pathways connected to its nuclear localization. Further investigation will be necessary to fully elucidate the function of Tes in the nuclear compartment. [less ▲]

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See detailSpin texture of two-dimensional topological insulators
Rod, Alexia Nibal UL

Doctoral thesis (2017)

Since the discovery of two-dimensional topological insulators a decade ago, their one-dimensional edge states have attracted significant attention due to their unique properties. For example due to time ... [more ▼]

Since the discovery of two-dimensional topological insulators a decade ago, their one-dimensional edge states have attracted significant attention due to their unique properties. For example due to time-reversal symmetry, they are protected against elastic backscattering and they propagate such that electrons with opposite spins move in opposite directions. In fact, the only necessary symmetry to sustain the edge states is time-reversal symmetry. Moreover in experimental setups, the axial spin symmetry seems to be absent. This absence allows new processes to appear such as inelastic backscattering. However, these consequences were neglected in most theoretical works where the spins are considered to be polarized in the z direction. The aim of this thesis is to provide a more realistic model taking into account a broken axial spin symmetry. In this scheme, we show that a rotation of the spin quantization axis as a function of momentum always appears. This observation leads us to develop a deeper understanding of the size of the rotation related to the material parameters and material models, using also realistic values. It also leads us to understand the implications in real space in cases where translation invariance is lost and how to quantify the rotation in such systems. The new processes which arise when the axial spin symmetry is broken have important consequences for transport in real materials. To see this, we consider a Hall bar with a hole in its middle, i.e. an antidot. This enables us to create two tunneling regions in order to probe the effect of this generic model. We also consider the effect of Coulomb interactions around the hole, as they can be important in such geometry. We discover that it is possible to probe directly the absence of axial spin symmetry. As experimental evidence is important to investigate our theoretical findings, we propose spectroscopic means to probe the spin texture. Finally, we also consider one of the experimentally-known candidate materials, namely InAs/GaSb heterostructures. From the k.p Hamiltonian, it is possible to show that their bandstructure shows some anisotropies. The latter is also reflected in the spin texture of their edge states. [less ▲]

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See detailKrankheitsbewältigung im Kontext einer Krebserkrankung im höheren Lebensalter
Lessing, Juliane Eva Margarethe UL

Doctoral thesis (2017)

The risk to develop cancer increases with age. Due to demographic change and extending life expectancy, the number of older cancer patients continues to grow. Despite this, the group of older cancer ... [more ▼]

The risk to develop cancer increases with age. Due to demographic change and extending life expectancy, the number of older cancer patients continues to grow. Despite this, the group of older cancer patients appears to be underrepresented in psycho-oncological research as well as in care and treatment. The present dissertation focuses on the psycho-social situation of older cancer patients in the Greater Region. Three main topics are studied using different methodological approaches. The first main topic focuses on the general situation of older cancer patients in Luxembourg. A descriptive analysis of epidemiological data from the Direction de la Santé and the International Agency for Research on Cancer shows increasing cancer incidence and mortality rates among older adults in Luxembourg. Comparative analyses using the Luxembourgish data from SHARE wave 5 show similar physical and psychological burden among older cancer patients (n = 44) and older cardiac patients (n = 46), but both patient groups report higher burden than older healthy adults (n = 51). Furthermore, in both patient groups, a percentage of about 22 % reports significant psychological burden. The second main topic focuses on the social context of older cancer patients analysing attitudes as well as emotional and behavioural reactions towards older cancer patients. Two quantitative studies using a 2x2x2 factorial vignette approach present each a brief scenario with varying information about a person´s gender, age (study 1: 30 vs. 74 years; study 2: 38 vs. 83 years) and health status (study 1: healthy vs. skin cancer; study 2: colon cancer vs. myocardial infarction). The two studies survey lay persons as well as health professionals and student health professionals (study 1: N = 683; study 2: N = 328). Both studies find no indicators of negative attitudes and reactions towards older cancer patients. However, study 1 shows more negative attitudes towards skin cancer patients but also higher prosocial emotions and less social distancing compared to healthy adults. In study 2, patients with colon cancer are rated as more thoughtful and less responsible for their disease than cardiac patients. Here, no differences are found in emotional or behavioural reactions. The third main topic focuses on individual experiences and coping processes of older cancer patients. Nine qualitative interviews with male and female cancer patients as well as a comparison group of male cardiac patients (each n = 3) between 64 and 90 years are conducted and analysed using qualitative content analysis. Results show that the diagnosis is perceived as a critical life event, but initial psychological burden decreases after the completion of treatment. Particularly, cognitive coping strategies are reported, above all acceptance and comparative processes. Psychological well-being as well as a sense of stability and continuity are maintained in spite of considerable physical changes and constraints. Practical implications of the findings are discussed. [less ▲]

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See detailCross-border evidence gathering: equality of arms within the EU?
van Wijk, Marloes Chantal UL

Doctoral thesis (2017)

The European Union (EU) has set the objective to develop an Area of Freedom, Security and Justice, in which on the one hand freedom of movement is promoted and on the other hand a high level of security ... [more ▼]

The European Union (EU) has set the objective to develop an Area of Freedom, Security and Justice, in which on the one hand freedom of movement is promoted and on the other hand a high level of security is ensured. The EU is therefore adopting measures to enhance international cooperation in criminal matters among the police and judicial authorities of its Member States. The adopted instruments concerning evidentiary matters, such as the gathering, freezing and/or confiscation of information and materials in another EU Member State, seem to serve the main purpose of assisting the authorities in investigating and prosecuting (cross-border) crime. This raises the question to what extent the defence is also given the possibility to gather – or to have gathered – information and materials in another EU Member State with the aim of preparing and presenting its case at trial and, in particular, whether the current (EU) legal framework on cross-border evidence gathering meets the requirements of the principle of equality of arms. This thesis addresses this question by, first of all, discussing the concept of equality of arms, as enshrined in both Article 6 ECHR and Article 47 CFR. It explains to what extent this principle is applicable to cross-border or transnational criminal proceedings and whether it has an autonomous meaning within the EU. In addition, it discusses which requirements can be deduced from the principle in relation to the possibilities of the defence to gather evidence in another EU Member State to prepare and presents its case. Subsequently, the focus is on the development of the European legislation – from both the Council of Europe and the EU – regulating the procedure of cross-border evidence gathering over the last decades. The aim is to explain the position of the defence in this development and to what extent the European legislation gives opportunities to the defence to request the assistance of foreign authorities in obtaining specific information and materials in another EU Member State. In order to understand how the European legislation is applied in practice by the EU Member States, this thesis includes a comparative study of three national jurisdictions: the Netherlands, England and Wales, and Italy. These three jurisdictions each represent a different criminal justice system, either more inquisitorial or adversarial in nature. The comparative study describes how a chosen jurisdiction interprets the principle of equality of arms. Furthermore, it examines to what extent the national jurisdiction allows the defence to carry out independent investigations abroad and how it gives the defence the opportunity to trigger the mechanism of international cooperation and to participate in the requested investigation. Finally, this thesis also includes an analysis of the criminal justice system of the International Criminal Court. In this system evidence gathering depends most of the time on State cooperation and both the Prosecutor and the defence are allowed to conduct independent investigations and seek the assistance of States. It is therefore used as a source of inspiration for potential changes of the EU legislation on cross-border evidence gathering. [less ▲]

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See detailIntegration of the analysis of non-functional properties in Model-Driven Engineering for embedded systems
Brau, Guillaume Sylvain Denis UL

Doctoral thesis (2017)

The engineering of embedded systems relies on two complementary activities: modeling on the one hand enables to represent the system, analysis on the other hand makes it possible to evaluate the various ... [more ▼]

The engineering of embedded systems relies on two complementary activities: modeling on the one hand enables to represent the system, analysis on the other hand makes it possible to evaluate the various non-functional properties (for example, temporal properties with the real-time scheduling analysis). This thesis deals with the integration between these models and analyses: how to apply an analysis on a model? How to manage the analysis process? The first part of this thesis presents a comprehensive approach to answer these questions. This approach is based on four application layers: (1) models to represent the system, (2) accessors to extract data from a model, (3) analyses to compute output data and/or properties from input data (4) contracts to represent the analysis interfaces and orchestrate the analysis process. The second part of this thesis deals with the experimentation of this approach with concrete systems coming from the aerospace: a drone, an exploratory robot and a flight management system. We demonstrate that the accessors enable to apply various real-time scheduling analyses on heterogeneous architectural models, for example written with the industry standard AADL (Architecture Analysis and Design Language) or the new time-triggered language CPAL (Cyber-Physical Action Language). In addition, contracts make it possible to automate complex analysis procedures: which analysis can be applied on a given model? Which are the analyses that meet a given goal? Are there analyses to be combined? Are there interferences between analyses? Etc. [less ▲]

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See detailHospice. Lieux et expériences de vieillesses. Bruxelles 1830-1914
Richelle, Sophie Marthe UL

Doctoral thesis (2017)

History of old age and experiences of ageing poeple in those places in Brussels between 1830 and 1914

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See detailEntwicklung eines EDV-basierten Frühwarnsystems für die Blankaalabwanderung an der Mosel
Wendling, David UL

Doctoral thesis (2017)

The eel (Anguilla anguilla L.) is a fish that is mainly found in European waters. The River Moselle is among the bodies of water inhabited by this specimen. During the downstream migration into their ... [more ▼]

The eel (Anguilla anguilla L.) is a fish that is mainly found in European waters. The River Moselle is among the bodies of water inhabited by this specimen. During the downstream migration into their Atlantic spawning ground, silver eels often experience severe to fatal injuries while passing the turbines at the barrages. This annual migration takes place in a relatively narrow timeframe. Therefore, knowing the trigger or beginning of said migration, the mortality rate of the eels could be reduced by a fish-adapted turbine control or comparable protective measures. This thesis introduces an early warning system, which predicts the periods of silver eel emigration by means of certain abiotic factors. On the basis of the information gleaned from different studies and the experience gained from many years of professional fishing, those environmental factors were identified which are connected with the migration of the silver eel. Extensive data analyses were used to substantiate these findings. The water flow, the flow differences and the lunar phase were particularly relevant. Furthermore, the season and the water temperature were taken into account. In view of the different sources of information (experience and expert knowledge, data sets and the findings derived from it), a hybrid structure of the early warning system was realized. After examining different methods from the fields of soft computing and mathematics or statistics, the fuzzy logic (knowledge-based), the case-based reasoning (casebased) and the artificial neural networks (data-based) were selected. With each of these methods, an independent prediction model was designed, tested and optimized. Special characteristics were found during the data analysis and were taken into account by the use of adequate modifiers. The models were tested on the basis of the present data sets for the Moselle. It was shown that it is possible to correctly predict most of the situations with increased catches (suggesting a migration). Threshold values for a migration were defined based on the catches. The same was done for the forecast values. Thus, for the 1963 to 1973 data record, a total of 63% (artificial neural networks), 74% (fuzzy logic), and 83% (case-based reasoning) of the events with increased catches could be detected. Since not every situation with a favorable constellation of abiotic factors also led to a migration or higher catches, a lot of "false" forecasts (up to 50%) were made as well. Good results have also been achieved when using data from recent years and most events were identified. A stand-alone program was developed for the practical application of the prognosis models. This early warning system is a software which contains a user interface for reading data and displaying prognosis values and into which the developed prognosis models are implemented. In addition, recommendations for use were compiled and presented. [less ▲]

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See detailMicroRNA regulation of hypoxia-induced tumorigenicity and metastatic potential of colon tumor-initiating cells
Ullmann, Pit UL

Doctoral thesis (2017)

The initiaton and progression of colorectal cancer (CRC), which is the second most common cause of cancer mortality in Western countries, are driven by a subpopulation of highly tumorigenic cells, known ... [more ▼]

The initiaton and progression of colorectal cancer (CRC), which is the second most common cause of cancer mortality in Western countries, are driven by a subpopulation of highly tumorigenic cells, known as cancer stem cells or tumor-initiating cells (TICs). These self-renewing TICs are, to a large extent, responsible for therapy resistance, cancer recurrence, and metastasis formation. TICs are known to extensively interact with their microenvironment and can be influenced by various extrinsic factors, such as inflammatory signaling or tumor hypoxia. Previous expression profiling studies have shown that microRNAs (miRNAs) are involved in the regulation of CRC inititation and metastatic progression. Moreover, specifc miRNAs have been identified as potential mediators of the cellular response to hypoxia. On the other hand, the molecular mechanisms that link hypoxia, miRNA expression, colon TIC regulation, and CRC progression, remain poorly understood. Thus, the main objectives of this work were to analyze the effects of hypoxia on the miRNA expression of colon TICs and to identify miRNAs that regulate metastasis initiation. In a first phase, we generated and thoroughly characterized different stable TIC-enriched spheroid cultures (SCs), both from CRC cell lines and from primary patient material. Each established SC was thereby shown to display key TIC properties, including substantial plasticity, in vitro and in vivo self-renewal capacity and, most importantly, extensive tumorigenic potential. Moreover, the individual SCs displayed increased chemoresistance capacity, compared to adherent counterpart cultures. Taken together, we could demonstrate that the spheroid system is a suitable model to study colon TICs, thereby laying the methodological foundation for the following subparts of this project. In a second step, we studied the influence of hypoxia on the miRNA expression profile of our established SCs. MiR-210-3p was thereby identified as the miRNA with the strongest response to hypoxia. Importantly, both hypoxic culture conditions and stable overexpression of miR-210 were shown to promote in vitro and in vivo self-renewal capacity of our colon TIC-enriched cultures. Moreover, by promoting lactate production and by repressing mitochondrial respiration, miR-210 was found to trigger the metabolic reprogramming of colon TICs towards a glycolytic and aggressive phenotype. Finally, we studied the role of miRNAs in the context of TIC-driven metastasis formation. By comparing primary tumor- and lymph node metastasis-derived SCs, we were able to identify the miR-371~373 cluster as an important regulator of tumorigenic and metastatic potential. Stable overexpression of the entire miR-371~373 cluster, followed by gene and protein expression analysis, enabled us to uncover the transforming growth factor beta receptor II (TGF-βRII) and the inhibitor of DNA binding 1 (Id1) as miR-371~373 cluster-responsive proteins. Most importantly, different sphere, tumor, and metastasis formation assays revealed that the miR-371~373/TGF-βRII/Id1 signaling axis regulates the self-renewal capacity and metastatic colonization potential of colon TICs. Taken together, our findings emphasize the strong plasticity of colon TICs and clearly illustrate that miRNAs can act as potent modulators of essential TIC properties. Accordingly, we could show that miR-210 and the miR-371~373 cluster are involved in metabolic reprogramming of TICs and in the regulation of metastasis formation, respectively. Altogether, our study contributes to a better understanding of the molecular mechanisms that drive TIC-induced tumor progression and may provide indications for interesting miRNA biomarker candidates and target molecules for future TIC-specific therapies. [less ▲]

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See detailScarring effects across the life course and the transition to retirement
Ponomarenko, Valentina UL

Doctoral thesis (2017)

This thesis investigates the long-term negative effects of unemployment, labour market inactivity and atypical employment. Within the theoretical framework of cumulative advantages and disadvantages, it ... [more ▼]

This thesis investigates the long-term negative effects of unemployment, labour market inactivity and atypical employment. Within the theoretical framework of cumulative advantages and disadvantages, it is outlined how life-course differentiation creates gaps between age peers and cohorts and how this leads to social inequality in old age. In the three separate, but linked studies, disadvantages across the career and their associations to retirement are analysed. The focus of the analyses is laid on the outcomes of career disadvantages in form of subjective and financial well-being. The three studies all use the Survey of Health, Ageing and Retirement in Europe. This large and multidimensional panel study provides not only prospective, but also retrospective data on European countries. The data base is employed in different combinations in the studies. In the first and second study, the retrospective wave SHARELIFE provides information on employment biography and is related to well-being indicators of the regular waves. In the third study, the persistence of disadvantages upon retirement is observed with a causal model. The first study investigates how disadvantages are affecting careers and subjective well-being of older Europeans. In two complementary analyses, first the employment history of older Europeans is studied with sequence analysis methods to show how non-employment and part-time work shape careers and to illustrate gender differences. In a second step, indicators of timing and duration, exemplifying the accumulation mechanisms, are related to subjective well-being in old age. The results indicate that women experience more turbulent careers with more periods of non-employment and part-time employment. However, this is not reflected in lower subjective well-being in old age. Accumulation of non-employment disadvantages is far more comprehensive for men than for women. Part-time employment has an ambiguous effect for women, but is not relevant for men. In the second study, the household level is added and it is analysed how an adverse employment history is related to wealth accumulation. The results show that cumulative non-employment and employment in lower occupations has significant disadvantages for wealth accumulation in old age. However, large differences for men and women remain. Particularly, the household composition and household factors are decisive in the effectuality of these disadvantages. The third study includes the scarring question, that means if career disadvantages continue beyond the working life. The study examines whether non-employment disadvantages are still found in retirement and the extent to which well-being levels change in the transition to retirement. Well-being scores before and after retirement are obtained and unbiased effects of the retirement transition are identified. Results indicate that being unemployed before retirement is associated with an increase in life satisfaction, but presents mainly a catching-up effect compared to employed persons transitioning to retirement. Findings are robust to selection into unemployment and country differences. [less ▲]

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See detailThe spread of public-private partnerships: a political economy analysis
Liebe, Moritz UL

Doctoral thesis (2017)

Amid a general trend to redefine and reform public services, public authorities around the globe have introduced and experimented with innovative ways of involving private actors in the provision of ... [more ▼]

Amid a general trend to redefine and reform public services, public authorities around the globe have introduced and experimented with innovative ways of involving private actors in the provision of public infrastructure and services — often referred to as Public-Private Partnerships (PPPs). Infrastructure-related PPPs are, usually, a contractual arrangement for a single undertaking to build and refurbish an asset where the public authority would mandate a single company to arrange the financing of the endeavour, to design and build the project, to be in charge of the maintenance and even, on some occasions, to manage the operation of public services related to the asset. A number of European national and regional governments and the European Union institutions have showed great interest in PPPs as an alternative procurement method, whereas some governments have abstained from this trend entirely or only used PPPs sporadically. This thesis — operationalised by a mix of qualitative and quantitative methods — is an inquiry into what factors inform the decision of public authorities to engage with PPPs more frequently. It involves testing a number of specific hypotheses generated to explain differential national engagement with PPPs, notably: the efficiency and effectiveness of the state (expressed as the state of public finances and the performance of public services); and a number of institutional variables — with institutions understood in this context as the incentives and constraints imposed by the national political system and the dominant mode of capitalism. This study reconfirms findings from the PPP literature on the conditions under which public authorities are more likely to have recourse to PPPs — i.e., authorities with less than optimally performing public services and/or experiencing budgetary constraints are expected to use PPPs more frequently. This thesis, however, also argues that other institutional factors are equally important for the likelihood of countries using this alternative procurement and financing method. On the one hand, the findings suggest that the ability of governments to introduce reforms — in the form of a favourable veto point structure in the political system and the government’s relative power vis-à-vis opposition parties — is a significant predictor for the numbers of established PPPs. On the other hand, the analysis shows the relevance of the economic system; the analysis reveals that the traditional mode of coordination in the national economy — i.e., either through contracts or non-market relations — has a greater influence on PPP uptake than commonly discussed in the literature. [less ▲]

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See detailNew models to study the cross-talk between the protein repair L-isoaspartyl methyltransferase and cell signalling
Soliman, Remon UL

Doctoral thesis (2017)

Isomerization of L-aspartyl and L-asparaginyl residues to form L-isoaspartyl residues in proteins is one type of protein damage that can occur under physiological conditions and can potentially lead to ... [more ▼]

Isomerization of L-aspartyl and L-asparaginyl residues to form L-isoaspartyl residues in proteins is one type of protein damage that can occur under physiological conditions and can potentially lead to conformational change, loss of function and enhanced protein degradation. Protein L-isoaspartyl methyltransferase (PCMT or PIMT) is a repair enzyme, which allows the reconversion of L-isoaspartyl residues to L-aspartyl residues in protein. Although the catalytic function of PCMT is known, its physiological roles remain less well understood. Pcmt1 gene knockout in mice leads for example, via molecular mechanisms that remain mostly obscure, to activation of insulin/IGF-1 and MAPK signalling pathways in the brain, and premature death due to massive epileptic seizure events. In this doctoral research project, we have used both mammalian cells and zebrafish models to investigate the impact of PCMT deficiency on insulin/IGF-1, MAPK and calcium signalling as well as how PCMT may be involved in epilepsy. In mammalian cells we used shRNA and CRISPR/Cas9 technology to reduce or completely silence PCMT expression, with the main objective being to mimic, in cell culture, the activation of the IGF-1 and MAPK signalling pathways observed in Pcmt1 knockout mice in the hope to thereby increase the chances to elucidate the underlying molecular mechanisms. In zebrafish we used an antisense morpholino-based strategy to knock down both PCMT homologs and thereby establish a new whole organism model to further study the physiological functions of PCMT, more particularly in the brain. Our results indicate that insulin/IGF-1 signalling is not affected by PCMT knockdown or knockout in mammalian cells whereas a time-dependent MAPK pathway activation could be detected in a Pcmt1 knockout mouse hippocampal cell line. In zebrafish, we showed that the two PCMT homologs Pcmt and Pcmtl (Pcmt/l) possess isoaspartyl methyltransferase activity. In pcmt/l knockdown (or morphant) zebrafish larvae we did not detect abnormal electrical activity in the brain, but we identified movement impairment and strongly perturbed brain calcium fluxes. Abnormal calcium responses were also observed in the Pcmt1 knockout mouse hippocampal cell line. We concluded that the interplay between PCMT and growth signalling pathways is highly dependent on experimental model and may not be amenable to investigation in cell culture. Importantly, our results clearly show that PCMT plays a pivotal role in calcium signalling and suggest that PCMT-dependent repair mechanisms may be important to prevent calcium-related neurological disorders. [less ▲]

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See detailStudy of Metabolite Repair in Eukaryotic Cells: Metabolic origin and fate of D-2-hydroxyglutarate in yeast and effect of NAD(P)HX repair deficiency on yeast and human cells
Becker-Kettern, Julia UL

Doctoral thesis (2017)

Abnormal metabolites, which are useless and can even be toxic, are constantly generated inside the cell by unwanted chemical reactions or by enzymatic side reactions. Metabolite repair enzymes clean the ... [more ▼]

Abnormal metabolites, which are useless and can even be toxic, are constantly generated inside the cell by unwanted chemical reactions or by enzymatic side reactions. Metabolite repair enzymes clean the metabolite pool from these molecules. The proportion of proteins annotated as metabolite repair enzymes is currently very small but accumulating evidence suggests that a bigger part might be hidden among proteins of unknown function. The aim of this thesis was to study two of these metabolite repair systems and their physiological relevance in more detail as their importance is well illustrated through implication in disease processes. D-2-hydroxyglutaric aciduria, a severe human neurometabolic disorder, can be caused by a deficiency in the metabolite repair enzyme D-2-hydroxyglutarate (D-2HG) dehydrogenase. Higher levels of D-2HG have also been observed in cancerous cells with a mutated form of isocitrate dehydrogenase. Strikingly, in the model organism Saccharomyces cerevisiae, 2-hydroxyglutarate metabolism had remained completely unexplored. We elucidated the metabolic pathways involved in D-2HG formation and degradation in yeast using bioinformatics, metabolomics, yeast genetics, and classical biochemical tools. We discovered that Dld3, currently annotated as a D-lactate dehydrogenase, actually degrades D-2HG to α-ketoglutarate while reducing pyruvate to D-lactate, thereby acting as a transhydrogenase. We also demonstrated that the yeast phosphoglycerate dehydrogenases Ser3 and Ser33 are major sources for D-2HG formation. These findings paved the way to integrate 2HG and its associated genes into the yeast metabolic network and might help, on the long-term, to better understand underlying mechanisms in human disease as well. Other recently identified metabolite repair enzymes, NAD(P)HX dehydratase and NAD(P)HX epimerase (encoded in yeast by the YKL151C and YNL200C genes, respectively), specifically act on NADHX and NADPHX, hydrated and inactive forms of the central NADH and NADPH cofactors. Although extensively biochemically characterized, the physiological importance of these two enzymes still remains largely unclear. Only very recently, case reports were published indicating a correlation between NAD(P)HX repair deficiency and severe neuropathological symptoms starting in early childhood upon events of febrile illnesses and rapidly leading to a fatal outcome. We systematically analyzed extracts of NAD(P)HX repair deficient yeast and human cells using HPLC and LC-MS/MS methods. This enabled us to demonstrate that NADHX and NADPHX can be formed intracellularly. In the yeast system, NADHX accumulation, which could be modulated by the cultivation temperature, was accompanied by a decrease in intracellular NAD+ levels. Furthermore, we showed that NADHX interferes with serine metabolism by inhibiting the first step of the main synthesis pathway of this amino acid. In the human cell system, NAD(P)HX dehydratase deficiency led, as in yeast, to intracellular NADHX accumulation, but also to a marked decrease in cell viability after prolonged cultivation times. This is, to our knowledge, the first report about the effect of NADHX accumulation on cellular metabolism. Expanding our experimental strategy of combined transcriptomics and metabolomics approaches to the human cell model might ultimately lead to the discovery of the disease-causing cellular process. The findings in both projects led to an unexpected connection between NAD(P)HX and 2HG metabolism via the yeast homologues of 3-phoshpoglycerate dehydrogenase, Ser3 and Ser33. Both proteins catalyze the oxidation of 3-phosphoglycerate to 3-phosphohydroxypyruvate in the initial step of de novo serine biosynthesis with a concomitant reduction of α-ketoglutarate to D-2-hydroxyglutarate. By acting as transhydrogenases, they substantially, even though not exclusively, contribute to D-2HG formation in yeast. The very same enzymes were strongly inhibited in vitro and, as suggested by our findings, also in vivo by the presence of NADHX, leading to serine depletion in NAD(P)HX repair deficient cells. [less ▲]

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See detailESSAYS IN PRICE DISCOVERY
Wells, René Joseph Guy UL

Doctoral thesis (2017)

I claim that uninformed traders prefer ending the size of their orders with a zero (e.g. 110 shares) but it is not the case for informed traders, creating an information channel and providing a signal. I ... [more ▼]

I claim that uninformed traders prefer ending the size of their orders with a zero (e.g. 110 shares) but it is not the case for informed traders, creating an information channel and providing a signal. I propose the Last Digit Hypothesis (LDH): i) some traders exhibit a last digit preference for the digit 0 and other traders do not while ii) the latter are better able to trade on information than the former. The LDH predicts that a trade arising from a marketable order with a size ending with a 0 on average contributes less to price discovery than other trades. My empirical findings support the LDH. However, the LDH is not an equilibrium since informed traders have an incentive to mimic the preferences of uninformed traders to avoid detection and face little constraints or costs to do so. It is puzzling that I find no evidence of such mimicking. I offer plausible explanations for this finding. I carefully test the Stealth Trading Hypothesis (STH) using comprehensive datasets for the three largest European equity markets over 2002 to 2015, a period that saw trading moved into a new era. I find little support for the STH and, in fact, the commonality between these three distinct markets is the convergence over time of price discovery by trade size. It could be explained by informed traders once facing less frictions are better able to mimic the trade size choice of uninformed traders and/or more price discovery now going through resting limit orders. [less ▲]

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See detailSLA Violation Detection Model and SLA Assured Service Brokering (SLaB) in Multi-Cloud Architecture
Wagle, Shyam Sharan UL

Doctoral thesis (2017)

Cloud brokering facilitates Cloud Service Users (CSUs) to find cloud services according to their requirements. In the current practice, CSUs or Cloud Service Brokers (CSBs) select cloud services according ... [more ▼]

Cloud brokering facilitates Cloud Service Users (CSUs) to find cloud services according to their requirements. In the current practice, CSUs or Cloud Service Brokers (CSBs) select cloud services according to Service Level Agreement (SLA) committed by Cloud Service Providers (CSPs) in their website. In our observation, it is found that most of the CSPs do not fulfill the service commitment mentioned in the SLA agreement. Verified cloud service performances against their SLA commitment of CSPs provide an additional trust on CSBs to recommend services to the CSUs. In this thesis work, we propose a SLA assured service-brokering framework, which considers both committed and delivered SLA by CSPs in cloud service recommendation to the users. For the evaluation of the performance of CSPs, two evaluation techniques: Heat Map and Intuinistic Fuzzy Logic (IFL) are proposed, which include both directly measurable and non-measurable parameters in the performance evaluation CSPs. These two techniques are implemented using real data measured from CSPs. Both performance evaluation techniques rank/- sort CSPs according to their service performances. The result shows that Heat Map technique is more transparent and consistent in CSP performance evaluation than IFL technique. As cloud computing is location independent technology, CSPs should respect the current regulatory framework in delivering services to the users. In this work, regulatory compliance status of the CSPs is also analyzed and visualized in performance heat map table to provide legal status of CSPs. Moreover, missing points in their terms of service and SLA document are analyzed and recommended to add in the contract document. In the revised European data protection regulation (GPDR), data protection impact assessment (DPIA) is going to be mandatory for all organizations/tools. The decision recommendation tool developed using above mentioned evaluation techniques may cause potential harm to individuals in assessing data from multiple CSPs. So, DPIA is carried out to assess the potential harm/risks to individuals due to decision recommendation tool and necessary precaution to be taken in decision recommendation tool to minimize possible data privacy risks. To help CSUs in easy decision making to select cloud services from multi-cloud environment, service pattern analysis techniques and prediction of future performance behavior of CSPs are also proposed in the thesis work. Prediction patterns and error measurement shows that automatic prediction methods can be implemented for short time period as well as longer time period. [less ▲]

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See detailKey-Recovery Attacks Against Somewhat Homomorphic Encryption Schemes
Chenal, Massimo UL

Doctoral thesis (2017)

In 1978, Rivest, Adleman and Dertouzos introduced the concept of privacy homomorphism and asked whether it is possible to perform arbitrary operations on encrypted ciphertexts. Thirty years later, Gentry ... [more ▼]

In 1978, Rivest, Adleman and Dertouzos introduced the concept of privacy homomorphism and asked whether it is possible to perform arbitrary operations on encrypted ciphertexts. Thirty years later, Gentry gave a positive answer in his seminal paper at STOC 2009, by proposing an ingenious approach to construct fully homomorphic encryption (FHE) schemes. With this approach, one starts with a somewhat homomorphic encryption (SHE) scheme that can perform only limited number of operations on ciphertexts (i.e. it can evaluate only low-degree polynomials). Then, through the so-called bootstrapping step, it is possible to turn this SHE scheme into an FHE scheme. After Gentry's work, many SHE and FHE schemes have been proposed; in total, they can be divided into four categories, according to the hardness assumptions underlying each SHE (and hence, FHE) scheme: hard problems on lattices, the approximate common divisor problem, the (ring) learning with errors problem, and the NTRU encryption scheme. Even though SHE schemes are less powerful than FHE schemes, they can already be used in many useful real-world applications, such as medical and financial applications. It is therefore of primary concern to understand what level of security these SHE schemes provide. By default, all the SHE schemes developed so far offer IND-CPA security - i.e. resistant against a chosen-plaintext attack - but nothing is said about their IND-CCA1 security - i.e. secure against an adversary who is able to perform a non-adaptive chosen-ciphertext attack. Considering such an adversary is in fact a more realistic scenario. Gentry emphasized it as a future work to investigate SHE schemes with IND-CCA1 security, and the task to make some clarity about it was initiated by Loftus, May, Smart and Vercauteren: at SAC 2011 they showed how one family of SHE schemes is not IND-CCA1 secure, opening the doors to an interesting investigation on the IND-CCA1 security of the existing schemes in the other three families of schemes. In this work we therefore continue this line of research and show that most existing somewhat homomorphic encryption schemes are not IND-CCA1 secure. In fact, we show that these schemes suffer from key recovery attacks (stronger than a typical IND-CCA1 attack), which allow an adversary to completely recover the private keys through a number of decryption oracle queries. As a result, this dissertation shows that all known SHE schemes fail to provide IND-CCA1 security. While it is true that IND-CPA security may be enough to construct cryptographic protocols in presence of semi-honest attackers, key recovery attacks will pose serious threats for practical usage of SHE and FHE schemes: if a malicious attacker (or a compromised honest party) submits manipulated ciphertexts and observes the behavior (side channel leakage) of the decryptor, then it may be able to recover all plaintexts in the system. Therefore, it is very desirable to design SHE and FHE with IND-CCA1 security, or at least design them to prevent key recovery attacks. This raises the interesting question whether it is possible or not to develop such IND-CCA1 secure SHE scheme. Up to date, the only positive result in this direction is a SHE scheme proposed by Loftus et al. at SAC 2011 (in fact, a modification of an existing SHE scheme and IND-CCA1 insecure). However, this IND-CCA1 secure SHE scheme makes use of a non standard knowledge assumption, while it would be more interesting to only rely on standard assumptions. We propose then a variant of the SHE scheme proposed by Lopez-Alt, Tromer, and Vaikuntanathan at STOC 2012, which offers good indicators about its possible IND-CCA1 security. [less ▲]

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See detailDie Rolle kleiner Städte und zentraler Orte im mittelalterlichen Herzogtum Luxemburg
Platt, Michèle Dorothy UL

Doctoral thesis (2017)

Diese Forschungsarbeit basiert auf der Untersuchung verschiedener Aspekte der urbanen Entwicklung verschiedener kleinerer Siedlungen vom 13. bis zum 16. Jahrhundert und soll deren Bedeutung auf mehreren ... [more ▼]

Diese Forschungsarbeit basiert auf der Untersuchung verschiedener Aspekte der urbanen Entwicklung verschiedener kleinerer Siedlungen vom 13. bis zum 16. Jahrhundert und soll deren Bedeutung auf mehreren Ebenen aufzeigen. Konkret stehen die im spätmittelalterlichen Herzogtum Luxemburg gelegenen Zentren Arrancy, Arlon, Bastogne, Bitburg, Damvillers, Diekirch, Durbuy, Chiny, Echternach, Grevenmacher, Houffalize, Ivoix, La Roche, Larochette, Marche, Marville, Remich, St. Vith, Thionville, Vianden und Virton im Fokus der Untersuchung. Es sollen nicht nur der urbane Entwicklungsprozess der einzelnen Orte bis 1600 und deren zentrale Funktionen in politisch-administrativer, rechtlicher, wirtschaftlicher, sozialer und kirchlich-kultureller Hinsicht aufgezeigt, sondern auch die Ausbildung des luxemburgischen Städtenetzes als Ganzes analysiert werden. Untersucht wird, zu welchem Ausmaß und zu welchem Zeitpunkt urbane Kriterien und Funktionen in den verschiedenen Zentren nachgewiesen werden können. Herausgestellt wurde ob und ab welchem Zeitpunkt die untersuchten Orte als kleine Stadt bzw. als Zentrum zu bezeichnen sind. Die Forschungsarbeit zeigt wann sich die urbanen Merkmale und zentrale Funktionen in den verschiedenen Orten häuften und wie weit der Einflussbereich dieser Zentren in das umliegende Gebiet hinausreichte. Es wurde die Bedeutung dieser Zentren auf lokaler Ebene sowie für das gesamte Territorium und die Herrschaftsträger ermittelt. Es wurde zum einen die Rolle der Städte und Zentren für die jeweiligen Bewohner und der umliegenden Gebiete herausgestellt und die Bedeutung der urbanen Entwicklung für die Einwohner dieser Orte analysiert. Im Vordergrund stand hierbei auch die Funktion und Bedeutung der Zentren für den Landesherrn und die landesherrliche Territorialpolitik. [less ▲]

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See detailDevelopment of an integrated omics in silico workflow and its application for studying bacteria-phage interactions in a model microbial community
Narayanasamy, Shaman UL

Doctoral thesis (2017)

Microbial communities are ubiquitous and dynamic systems that inhabit a multitude of environments. They underpin natural as well as biotechnological processes, and are also implicated in human health. The ... [more ▼]

Microbial communities are ubiquitous and dynamic systems that inhabit a multitude of environments. They underpin natural as well as biotechnological processes, and are also implicated in human health. The elucidation and understanding of these structurally and functionally complex microbial systems using a broad spectrum of toolkits ranging from in situ sampling, high-throughput data generation ("omics"), bioinformatic analyses, computational modelling and laboratory experiments is the aim of the emerging discipline of Eco-Systems Biology. Integrated workflows which allow the systematic investigation of microbial consortia are being developed. However, in silico methods for analysing multi-omic data sets are so far typically lab-specific, applied ad hoc, limited in terms of their reproducibility by different research groups and suboptimal in the amount of data actually being exploited. To address these limitations, the present work initially focused on the development of the Integrated Meta-omic Pipeline (IMP), a large-scale reference-independent bioinformatic analyses pipeline for the integrated analysis of coupled metagenomic and metatranscriptomic data. IMP is an elaborate pipeline that incorporates robust read preprocessing, iterative co-assembly, analyses of microbial community structure and function, automated binning as well as genomic signature-based visualizations. The IMP-based data integration strategy greatly enhances overall data usage, output volume and quality as demonstrated using relevant use-cases. Finally, IMP is encapsulated within a user-friendly implementation using Python while relying on Docker for reproducibility. The IMP pipeline was then applied to a longitudinal multi-omic dataset derived from a model microbial community from an activated sludge biological wastewater treatment plant with the explicit aim of following bacteria-phage interaction dynamics using information from the CRISPR-Cas system. This work provides a multi-omic perspective of community-level CRISPR dynamics, namely changes in CRISPR repeat and spacer complements over time, demonstrating that these are heterogeneous, dynamic and transcribed genomic regions. Population-level analysis of two lipid accumulating bacterial species associated with 158 putative bacteriophage sequences enabled the observation of phage-host population dynamics. Several putatively identified bacteriophages were found to occur at much higher abundances compared to other phages and these specific peaks usually do not overlap with other putative phages. In addition, there were several RNA-based CRISPR targets that were found to occur in high abundances. In summary, the present work describes the development of a new bioinformatic pipeline for the analysis of coupled metagenomic and metatranscriptomic datasets derived from microbial communities and its application to a study focused on the dynamics of bacteria-virus interactions. Finally, this work demonstrates the power of integrated multi-omic investigation of microbial consortia towards the conversion of high-throughput next-generation sequencing data into new insights. [less ▲]

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See detailFinancial Intermediation and Macroeconomic Fluctuations
Chevallier, Claire Océane UL

Doctoral thesis (2017)

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See detailPrivate Functional Encryption – Hiding What Cannot Be Learned Through Function Evaluation
Delerue Arriaga, Afonso UL

Doctoral thesis (2017)

Functional encryption (FE) is a generalization of many commonly employed crypto- graphic primitives, such as keyword search encryption (KS), identity-based encryption (IBE), inner-product encryption (IPE ... [more ▼]

Functional encryption (FE) is a generalization of many commonly employed crypto- graphic primitives, such as keyword search encryption (KS), identity-based encryption (IBE), inner-product encryption (IPE) and attribute-based encryption (ABE). In an FE scheme, the holder of a master secret key can issue tokens associated with functions of its choice. Possessing a token for f allows one to recover f(m), given an encryption of m. As it is important that ciphertexts preserve data privacy, in various scenarios it is also important that tokens do not expose their associated function. A notable example being the usage of FE to search over encrypted data without revealing the search query. Function privacy is an emerging new notion that aims to address this problem. The difficulty of formalizing it lies in the verification functionality, as the holder of a token for function f may encrypt arbitrary messages using the public key, and obtain a large number of evaluations of f. Prior privacy models in the literature were fine-tuned for specific functionalities, did not model correlations between ciphertexts and decryption tokens, or fell under strong uninstantiability results. Our first contribution is a new indistinguishability-based privacy notion that overcomes these limitations and is flexible enough to capture all previously proposed indistinguishability-based definitions as particular cases. The second contribution of this thesis is five constructions of private functional encryption supporting different classes of functions and meeting varying degrees of security: (1) a white-box construction of an Anonymous IBE scheme based on composite-order groups, shown to be secure in the absence of correlated messages; (2) a simple and functionality- agnostic black-box construction from obfuscation, also shown to be secure in the absence of correlated messages; (3) a more evolved and still functionality-agnostic construction that achieves a form of function privacy that tolerates limited correlations between messages and functions; (4) a KS scheme achieving privacy in the presence of correlated messages beyond all previously proposed indistinguishability-based security definitions; (5) a KS construction that achieves our strongest notion of privacy (but relies on a more expressive form of obfuscation than the previous construction). The standard approach in FE is to model complex functions as circuits, which yields inefficient evaluations over large inputs. As our third contribution, we propose a new primitive that we call “updatable functional encryption” (UFE), where instead of circuits we deal with RAM programs, which are closer to how programs are expressed in von Neumann architecture. We impose strict efficiency constrains and we envision tokens that are capable of updating the ciphertext, over which other tokens can be subsequently executed. We define a security notion for our primitive and propose a candidate construction from obfuscation, which serves as a starting point towards the realization of other schemes and contributes to the study on how to compute RAM programs over public-key encrypted data. [less ▲]

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See detailOn Composability and Security of Game-based Password-Authenticated Key Exchange
Skrobot, Marjan UL

Doctoral thesis (2017)

The main purpose of Password-Authenticated Key Exchange (PAKE) is to allow secure authenticated communication over insecure networks between two or more parties who only share a low-entropy password. It ... [more ▼]

The main purpose of Password-Authenticated Key Exchange (PAKE) is to allow secure authenticated communication over insecure networks between two or more parties who only share a low-entropy password. It is common practice that the secret key derived from a PAKE execution is used to authenticate and encrypt some data payload using symmetric key protocols. Unfortunately, most PAKEs of practical interest, including three protocols considered in this thesis, are studied using so-called game-based models, which -- unlike simulation models -- do not guarantee secure composition per se. However, Brzuska et al. (CCS 2011) have shown that a middle ground is possible in the case of authenticated key exchange that relies on Public-Key Infrastructure (PKI): the game-based models do provide secure composition guarantees when the class of higher-level applications is restricted to symmetric-key protocols. The question that we pose in this thesis is whether or not a similar result can be exhibited for PAKE. Our work answers this question positively. More specifically, we show that PAKE protocols secure according to the game-based Real-or-Random (RoR) definition of Abdalla et al. (PKC 2005) allow for automatic, secure composition with arbitrary, higher-level symmetric key protocols. Since there is evidence that most PAKEs secure in the Find-then-Guess (FtG) model of Bellare et al. (EUROCRYPT 2000) are in fact secure according to the RoR definition, we can conclude that nearly all provably secure PAKEs enjoy a certain degree of composition, one that at least covers the case of implementing secure channels. Although many different protocols that accomplish PAKE have been proposed over last two decades, only a few newcomers managed to find their way to real world applications - albeit lacking an intense and prolonged public scrutiny. As a step in the direction of providing one, this dissertation considers the security and efficiency of two relatively recently proposed PAKE protocols - Dragonfly and J-PAKE. In particular, we prove the security of a very close variant of Dragonfly employing the standard FtG model which incorporates forward secrecy. Thus, our work confirms that Dragonfly's main flows are sound. Furthermore, we contribute to the discussion by proposing and examining (in the RoR model of security) two variants of J-PAKE - which we call RO-J-PAKE and CRS-J-PAKE - that each makes the use of two less zero-knowledge proofs than the original protocol, at the cost of an additional security assumption. Our work reveals that CRS-J-PAKE has an edge in terms of efficiency over J-PAKE for both standard group choices: subgroups of finite fields and elliptic curves. The same is true for RO-J-PAKE, but only when instantiated with elliptic curves. [less ▲]

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See detailLa fonction juridictionnelle au service de l’intégration sud-américaine. Regards croisés sur la contribution des juges régionaux à la construction d’un espace intégré : Europe et Amérique du Sud
Pena-Pinon, Mariana UL

Doctoral thesis (2017)

Regional integration is a global phenomenon understood in this book as “the association between sovereign States of a given geographical region, by international agreements with the aim of approximating ... [more ▼]

Regional integration is a global phenomenon understood in this book as “the association between sovereign States of a given geographical region, by international agreements with the aim of approximating national laws through a binding regional law”. In the context of South America, this definition had led to the study of six regional organizations, examined in a comparative manner to establish the degree of integration accomplished in this region. In a second step, the role of the law in an integrational organization and its control by a jurisdiction has been examined. Parallels are drawn between the role of the European Court of Justice and the EFTA Court and the regional jurisdictions in South America. Finally, the creation of a regional court through a Treaty, common to the six organizations compared is advocated. The political and legal feasibility, the precise characteristics, remedies and the character of the decisions of said regional court are discussed in depth. [less ▲]

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See detailMULTI-OBJECTIVE CLOUD BROKERING OPTIMIZATION TAKING INTO ACCOUNT UNCERTAINTY AND LOAD PREDICTION
Nguyen, Anh Quan UL

Doctoral thesis (2017)

Cloud broker optimization for energy-aware in multi-clouds system is to use a metaheuristic method for this multi-objective optimization problem that focuses on reducing the cost as well as improving the ... [more ▼]

Cloud broker optimization for energy-aware in multi-clouds system is to use a metaheuristic method for this multi-objective optimization problem that focuses on reducing the cost as well as improving the energy efficiency. This broad topic has been motivated by the energy-aware challenge at the level of cloud brokerage service. The cloud broker bases on multi-objectives optimization is characterized by a tightly coupled constraints, a dynamic environment, and changing objectives and priorities. That results in investigating specific aspects of the cloud brokerage service - virtual machine placement problem. [less ▲]

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See detailDesigning Compliance Patterns: Integrating Value Modeling, Legal Interpretation and Argument Schemes for Legal Risk Management.
Kiriinya, Robert Kevin Muthuri UL

Doctoral thesis (2017)

Companies must be able to demonstrate that their way of doing business is compliant with relevant rules and regulations. However, the law often has open texture; it is generic and needs to be interpreted ... [more ▼]

Companies must be able to demonstrate that their way of doing business is compliant with relevant rules and regulations. However, the law often has open texture; it is generic and needs to be interpreted before it can be applied in a specific case. Entrepreneurs generally lack the expertise to engage in the regulatory conversations that make up this interpretation process. In particular, for the application domain of technological startups, this leads to legal risks. This research seeks to develop a robust module for legal interpretation. We apply informal logic to bridge the gap between the principles of interpretation in legal theory with the legal rules that determine the compliance of business processes. Accordingly, interpretive arguments characterized by argument schemes are applied to business models represented by value modeling (VDML). The specific outcome of the argumentation process (if any) is then summarized into a compliance pattern, in a context-problem-solution format. Two case studies in the application area of startups shows that the approach is able to express the legal arguments, but is also understandable for the target audience. The project is presented in two parts; Part I, the background, contains an introduction, literature review, motivational case studies, a survey on legal risks, and a modeling of business and legal aspects. Part II builds on the interdisciplinary facets of the first part to develop the Compliance Patterns Framework which is then validated with two case studies followed by a conclusion. [less ▲]

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See detailOptical Characterization of Cu2ZnSnSe4 Thin Films
Sendler, Jan Michael UL

Doctoral thesis (2017)

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See detailComprehensive Specification and Efficient Enforcement of Role-based Access Control Policies using a Model-driven Approach
Ben Fadhel, Ameni UL

Doctoral thesis (2017)

Prohibiting unauthorized access to critical resources and data has become a major requirement for enterprises. Access control (AC) mechanisms manage requests from users to access system resources; the ... [more ▼]

Prohibiting unauthorized access to critical resources and data has become a major requirement for enterprises. Access control (AC) mechanisms manage requests from users to access system resources; the access is granted or denied based on the authorization policies defined within the enterprise. One of the most used AC paradigms is role-based access control (RBAC), in which access rights are determined based on the user’s role. In this dissertation, we focus on the problems of modeling, specifying and enforcing complex RBAC policies, by making the following contributions: 1. the GemRBAC+CTX conceptual model, a UML extension of the RBAC model that includes all the entities required to express the various types of RBAC policies found in the literature, with a specific emphasis on contextual policies. For each type of policy, we provided the corresponding formalization using the Object Constraint Language (OCL) to operationalize the access decision for a user’s request using model-driven technologies. 2. the GemRBAC-DSL language, a domain-specific language for RBAC policies designed on top of the GemRBAC+CTX model. The language is characterized by a syntax close to natural language, which does not require any mathematical background for expressing RBAC policies. The language supports all the authorization policies captured by the GemRBAC+CTX model. 3. MORRO, a model-driven framework for the run-time enforcement of RBAC policies expressed in GemRBAC-DSL, built on top of the GemRBAC+CTX model. MORRO provides policy enforcement for both access and usage control. 4. three tools (an editor for GemRBAC-DSL, a model transformation tool for GemRBAC-DSL, a run-time enforcement framework) have been implemented and released as part of this work. The GemRBAC+CTX model and the GemRBAC-DSL language have been adopted by our industrial partner for the specification of the access control policies of a Web application in the domain of disaster reliefintervention. We have extensively evaluated the applicability and the scalability of MORRO on this Web application. The experimental results show that an access decision can be made on average, in less than 107 ms and that the time for processing a notification of an AC-related event is less than 512ms. Furthermore, both the access decision time and the execution time for processing a notification of an AC-related event scale—in the majority of the cases—linearly with respect to the parameters characterizing AC configurations; in the remaining cases, the access decision time is constant. [less ▲]

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See detailUne étude acoustique et comparative sur les voyelles du luxembourgeois
Thill, Tina UL

Doctoral thesis (2017)

This thesis is part of a descriptive work in acoustic phonetics, with the aim of studying the productions of Luxembourgish vowels in native and non-native speech. Its objective is to conciliate the ... [more ▼]

This thesis is part of a descriptive work in acoustic phonetics, with the aim of studying the productions of Luxembourgish vowels in native and non-native speech. Its objective is to conciliate the variation of Luxembourgish, mainly a spoken language, composed of many regional varieties, evolving in a multilingual context, and the learning of Luxembourgish as a foreign language in the Grand-Duchy of Luxembourg. As we assume the fact that language acquisition implies knowledge of sound contrast in speech, we investigate the productions of speakers whose mother tongues have different features than Luxembourgish, such as French, to see whether if the contrast are reproduced in non-native speech. Productions of French speakers are compared to those of native speakers from the region around the capital city of the Grand-Duchy of Luxembourg, whose variety serves as a reference to the teaching of Luxembourgish as a foreign language. The purpose of the study is the following : - to extend the descriptions on the acoustic properties of vowels produced in a regional variety of the Grand-Duchy of Luxembourg, - to highlight the specific difficulties of productions by French learners of Luxembourgish, - to interpret the results regarding the teaching of Luxembourgish as a foreign language. Fieldwork and the creation of a corpus through recordings of 10 Luxembourg speakers and 10 French speakers are an important part of the empirical work. We obtained a corpus of 12 hours and a half of spoken and spontaneous speech, including native speech and not native of Luxembourgish and also native speech of French. This corpus represents a first corpus containing native and non-native speech of Luxembourgish and enables to conduct different comparative studies. In our thesis, we did comparative analyses of the data in read speech. The methodology we used made it possible to compare data of native and non-native speech and also data of the L1 and L2 of French speakers. The results gave information about native and non-native productions of vowels. They showed that, on the one hand, vowel productions vary among speakers, even if these speak the same regional variety and, on the other hand, French speakers who learn Luxembourgish at B1/B2 level have difficulties producing contrasts in Luxembourgish. This concerns: - the quantity of the long vowels [iː], [eː], [aː], [oː], [uː] and short vowels [i], [e], [ɑ], [ɔ]. [u], - the quality of the long vowel [aː] and the two short vowels [æ] and [ɑ], - the quality of the beginning of the diphthongs [æi], [æu], [ɑi], [ɑu]. These results as well as thorough descriptions of the vowels in native speech, extend knowledge not only of Luxembourgish, but also of the variety which serves as the reference for Luxembourgish as a foreign language. In addition, they open up prospects for studying Luxembourgish by problematizing the introduction of rules for this type of education, despite the absence of language instruction in schools and the evolution of regional varieties in a concentrated geographical area. [less ▲]

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See detailStochastic Thermodynamics for Underdamped Brownian Particles: Equivalent Measures, Reversed Stochastic Processes and Feynman-Kac Techniques
Shayanfard, Kamran UL

Doctoral thesis (2017)

Underdamped stochastic thermodynamics provides a handy tool to study a large class of stochastic processes operating out of equilibrium. Colloidal particles in a laser trap, molecular motors and feedback ... [more ▼]

Underdamped stochastic thermodynamics provides a handy tool to study a large class of stochastic processes operating out of equilibrium. Colloidal particles in a laser trap, molecular motors and feedback processes are some of the prominent examples. In the present work we give a mathematical framework for the study of the thermodynamic properties of these phenomena. We focus on Markovian stochastic processes in continuous time and space, and show how the techniques of equivalent measures combined with stochastic solutions of partial differential equations, obtained through Feynman-Kac formula, can be used to derive exact relations between forward and backward diffusion processes. We prove a theorem which allows us to derive the time evolution of an arbitrary path quantity in a simple and systematic way. We further consider a fairly general underdamped stochastic model, and study its nonequilibrium thermodynamic properties at both single trajectory and average levels. For this model, we establish several integral and detailed fluctuation theorems for thermodynamic quantities such as work and entropy production, amongst others. Some of these theorems directly parallel those already obtained in the context of overdamped and master equations, while others are novel. We also discuss some special cases of our model which are directly related to physical systems such as active Brownian particles, feedback processes and isoenergetic stochastic processes. The formalism we develop, and the general model considered here constitute a unified and extended framework for the study of the thermodynamics of underdamped processes, encompassing several physical systems and applications. [less ▲]

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See detailTax havens under international pressure: a game theoretical approach
Pulina, Giuseppe UL

Doctoral thesis (2017)

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See detailA Combined Unsupervised Technique for Automatic Classification in Electronic Discovery
Ayetiran, Eniafe Festus UL

Doctoral thesis (2017)

Electronic data discovery (EDD), e-discovery or eDiscovery is any process by which electronically stored information (ESI) is sought, identified, collected, preserved, secured, processed, searched for the ... [more ▼]

Electronic data discovery (EDD), e-discovery or eDiscovery is any process by which electronically stored information (ESI) is sought, identified, collected, preserved, secured, processed, searched for the ones relevant to civil and/or criminal litigations or regulatory matters with the intention of using them as evidence. Searching electronic document collections for relevant documents is part of eDiscovery which poses serious problems for lawyers and their clients alike. Getting efficient and effective techniques for search in eDiscovery is an interesting and still an open problem in the field of legal information systems. Researchers are shifting away from traditional keyword search to more intelligent approaches such as machine learning (ML) techniques. State-of-the-art algorithms for search in eDiscovery focus mainly on supervised approaches, mainly; supervised learning and interactive approaches. The former uses labelled examples for training systems while the latter uses human assistance in the search process to assist in retrieving relevant documents. Techniques in the latter approach include interactive query expansion among others. Both approaches are supervised form of technology assisted review (TAR). Technology assisted review is the use of technology to assist or completely automate the process of searching and retrieval of relevant documents from electronically stored information (ESI). In text retrieval/classification, supervised systems are known for their superior performance over unsupervised systems. However, two serious issues limit their application in the electronic discovery search and information retrieval (IR) in general. First, they have associated high cost in terms of finance and human effort. This is particularly responsible for the huge amount of money expended on eDiscovery on annual basis. Secondly, their case/project-specific nature does not allow for resuse, thereby contributing more to organizations' expenses when they have two or more cases involving eDiscovery. Unsupervised systems on the other hand, is cost-effective in terms of finance and human effort. A major challenge in unsupervised ad hoc information retrieval is that of vocabulary problem which causes terms mismatch in queries and documents. While topic modelling techniques try to tackle this from the thematic point of view in the sense that both queries and documents are likely to match if they discuss about the same topic, natural language processing (NLP) approaches view it from the semantic perspective. Scalable topic modelling algorithms, just like the traditional bag of words technique, suffer from polysemy and synonymy problems. Natural language processing techniques on the other hand, while being able to considerably resolve the polysemy and synonymy problems are computationally expensive and not suitable for large collections as is the case in eDiscovery. In this thesis, we exploit the peculiarity of eDiscovery collections being composed mainly of e-mail communications and their attachments, mining topics of discourse from e-mails and disambiguating these topics and queries for terms matching has been proven to be effective for retrieving relevant documents when compared to traditional stem-based retrieval. In this work, we present an automated unsupervised approach for retrieval/classification in eDiscovery. This approach is an ad hoc retrieval which creates a representative for each original document in the collection using latent dirichlet allocation (LDA) model with Gibbs sampling and explores word sense disambiguation (WSD) to give these representative documents and queries deeper meanings for distributional semantic similarity. The word sense disambiguation technique by itself is a hybrid algorithm derived from the modified version of the original Lesk algorithm and the Jiang & Conrath similarity measure. Evaluation was carried out on this technique using the TREC legal track. Results and observations are discussed in chapter 8. We conclude that WSD can improve ad hoc retrieval effectiveness. Finally, we suggest further work focusing on efficient algorithms for word sense disambiguation which can further improve retrieval effectiveness if applied to original document collections in contrast to using representative collections. [less ▲]

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See detailAndere Ordnungen: Heterotope Räume in den Romanen Christian Krachts
Kentges, Daliah UL

Doctoral thesis (2017)

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See detail‘WHAT DO YOU MEAN YOU LOST THE PAST?’ AGENCY, EXPRESSION AND SPECTACLE IN AMATEUR FILMMAKING
Wecker, Danièle UL

Doctoral thesis (2017)

The following thesis presents an examination of privately produced amateur films taken from the Amateur Film Archive in the Centre National d’Audiovisuel in Luxembourg. It analyzes how amateur films ... [more ▼]

The following thesis presents an examination of privately produced amateur films taken from the Amateur Film Archive in the Centre National d’Audiovisuel in Luxembourg. It analyzes how amateur films present a filmic world and examines specific notions of meaning generation without meta-data and original context. Rather than take amateur film as a homogenous genre or practice, this study concentrates on film language. The first part of the following two-fold engagement with these filmic worlds thus identifies the highly differentiated filmic modes that can be read from the images. A filmic mode is related to as a concomitance of style and choice in subject matter. Without original context, these films lose their most important means of meaning generation, namely the recollective narratives that are constructed by the intended audience in the viewing situation. This work operates from a basis of analysis that takes these images as remnants of a visual narration rather than in terms of recollective narratives. It operates from the very simple basis that what was filmed had significance for these filmmakers and how the camera was used can serve as illustration of underlying intentions and motivations—both intended and inadvertent. The first part of this study then focuses on the diversification within the images and reads concomitant cultural codifications that structure representational productions in the private and also analyzes film language as means of self-inscription and self-narration. The second part of this two-fold engagement explores filmic language in terms of a visualization of primordial signifying expression coming-into-being. It relates to amateur film and practice from a basis of primary Becoming rather than a fixed Being. This engagement extends to include the researcher and his/her own background as co-constitutive part of this process of primordial meaning coming-into-being. Film is related to as the opening of a filmic universe that presents its own structures and engagements and not as visualization of a profilmic world from the past. [less ▲]

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See detailCUSP FORMS FOR LOCALLY SYMMETRIC SPACES OF INFINITE VOLUME
Becker, Gilles UL

Doctoral thesis (2017)

Let G be a real simple linear connected Lie group of real rank one. Then, X := G/K is a Riemannian symmetric space with strictly negative sectional curvature. By the classification of these spaces, X is a ... [more ▼]

Let G be a real simple linear connected Lie group of real rank one. Then, X := G/K is a Riemannian symmetric space with strictly negative sectional curvature. By the classification of these spaces, X is a real-complex-quaternionic hyperbolic space or the Cayley hyperbolic plane. We define C(Г\G) on Г\G for torsion-free geometrically finite subgroups Г of G. We show that it has a Fréchet space structure, that the space of compactly supported smooth functions is dense in this space, that it is contained in L^2(Г\G) and that the right translation by elements of G defines a representation on C(Г\G). Moreover, we define the space of cusp forms °C(Г\G) on Г\G, which is a geometrically defined subspace of C(Г\G). It consists of the Schwartz functions which have vanishing ''constant term'' along the ordinary set Ω ⊂ ∂X and along every cusp. We show that these two constant terms are in fact related by a limit formula if the cusp is of smaller rank (not of full rank). The main result of this thesis consists in proving a direct sum decomposition of the closure of the space of cusp forms in L^2(Г\G) which respects the Plancherel decomposition in the case where Г is convex-cococompact and noncocompact. For technical reasons, we exclude here that X is the Cayley hyperbolic plane. [less ▲]

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See detailHousehold Nonemployment, Social Risks and Inequality in Europe
Hubl, Vanessa Julia UL

Doctoral thesis (2016)

The dissertation explores interactions between households, states and markets and their relation to socio-economic inequalities among working-age households. The focus lies on three aspects: the ... [more ▼]

The dissertation explores interactions between households, states and markets and their relation to socio-economic inequalities among working-age households. The focus lies on three aspects: the importance of the welfare state, economic risks and opportunities within households, and the link between these two aspects and broader patterns of inequality at the societal level. These are analysed in three empirical studies, using a range of statistical methods (multilevel analysis, event history models and counterfactual analyses of income distributions). In addition, an extensive framework paper provides a background to the analyses, clarifies their relation in theoretical terms, and discusses the results. The first empirical study explores the relation between the regulation of social benefits, social risks, and household nonemployment in 20 European countries using internationally comparative institutional and survey data. The study reveals that eligibility conditions and activation policy vary systematically with the effect of social risks on the probability of household nonemployment. The strength and direction of influence depends on the specific policy area and risk factor. The second study analyses the duration of household nonemployment for British and German couples from the early 1990s to the mid-2000s. Dual joblessness has become longer over time, which is related to changes in the household composition of nonemployed couples. The third analysis evaluates the consequences of welfare shifts between households on changing patterns of inequality between 2005 and 2010. Changes in the distribution of household employment, benefit transfers, and family types in Germany, the United Kingdom, Poland, and Spain are analysed in terms of their contribution to developments in income inequality between households. The analysis of income distributions suggests that changes in socio-demographic and economic household characteristics in a population can have a substantial impact on different income groups. The overarching conclusion of the dissertation is that certain aspects of household composition enhance the risk of lower economic activity and welfare but that the impact of these factors varies strongly according to the broader context the households are situated in. Social policies that have the potential to reduce inequalities between households need to consider possible adverse effects on economic risk structures and spill-over effects to other areas of social protection. Future research should continue studying the household’s role in relation to the market, the state, and individual needs and resources; incorporate additional economic and welfare regime aspects into the analyses; and explore further statistical tools to do so. [less ▲]

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See detailImages of Galois representations and p-adic models of Shimura curves
Amoros Carafi, Laia UL

Doctoral thesis (2016)

The thesis treats two questions situated in the Langlands program, which is one of the most active and important areas in current number theory and arithmetic geometry. The first question concerns the ... [more ▼]

The thesis treats two questions situated in the Langlands program, which is one of the most active and important areas in current number theory and arithmetic geometry. The first question concerns the study of images of Galois representations into Hecke algebras coming from modular forms over finite fields, and the second one deals with p-adic models of Shimura curves and its bad reduction. Consequently, the thesis is divided in two parts. The first part is concerned with the study of images of Galois representations that take values in Hecke algebras of modular forms over finite fields. The main result of this part is a complete classification of the possible images of 2-dimensional Galois representations with coefficients in local algebras over finite fields under the hypotheses that: (i) the square of the maximal ideal is zero, (ii) that the residual image is big (in a precise sense), and (iii) that the coefficient ring is generated by the traces. In odd characteristic, the image is completely determined by these conditions; in even characteristic the classification is much richer. In this case, the image is uniquely determined by the number of different traces of the representation, a number which is given by an easy formula. As an application of these results, the existence of certain p-elementary abelian extensions of big non-solvable number fields can be deduced. Whereas some aspects of class field theory are accessible through this approach, it can be applied to huge fields for which standard techniques totally fail. The second part of the thesis consists of an approach to p-adic uniformisations of Shimura curves X(Dp,N) through a combination of different techniques concerning rigid analytic geometry and arithmetic of quaternion orders. The results in this direction lean on two methods: one is based on the information provided by certain Mumford curves covering Shimura curves and the second one on the study of Eichler orders of level N in the definite quaternion algebra of discriminant D. Combining these methods, an explicit description of fundamental domains associated to p-adic uniformisation of families of Shimura curves of discriminant Dp and level N ≥ 1, for which the one-sided ideal class number h(D,N) is 1, is given. The method presented in this thesis enables one to find Mumford curves covering Shimura curves, together with a free system of generators for the associated Schottky groups, p-adic good fundamental domains and their stable reduction-graphs. As an application, general formulas for the reduction-graphs with lengths at p of the considered families of Shimura curves can be computed. [less ▲]

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See detailCohomologies and derived brackets of Leibniz algebras
Cai, Xiongwei UL

Doctoral thesis (2016)

In this thesis, we work on the structure of Leibniz algebras and develop cohomology theories for them. The motivation comes from: • Roytenberg, Stienon-Xu and Ginot-Grutzmann's work on standard and naive ... [more ▼]

In this thesis, we work on the structure of Leibniz algebras and develop cohomology theories for them. The motivation comes from: • Roytenberg, Stienon-Xu and Ginot-Grutzmann's work on standard and naive cohomology of Courant algebroids (Courant-Dorfman algebras). • Kosmann-Schwarzbach, Roytenberg and Alekseev-Xu's constructions of derived brackets for Courant algebroids. • The classical equivariant cohomology theory and the generalized geometry theory. This thesis consists of three parts: 1. We introduce standard cohomology and naive cohomology for a Leibniz algebra. We discuss their properties and show that they are isomorphic. By similar methods, we prove a generalization of Ginot-Grutzmann's theorem on transitive Courant algebroids, which was conjectured by Stienon-Xu. The relation between standard complexes of a Leibniz algebra and its corresponding crossed product is also discussed. 2. We observe a canonical 3-cochain in the standard complex of a Leibniz algebra. We construct a bracket on the subspace consisting of so-called representable cochains, and prove that the subspace becomes a graded Poisson algebra. Finally we show that for a fat Leibniz algebra, the Leibniz bracket can be represented as a derived bracket. 3. In spired by the notion of a Lie algebra action and the idea of generalized geometry, we introduce the notion of a generalized action of a Lie algebra g on a smooth manifold M, to be a homomorphism of Leibniz algebras from g to the generalized tangent bundle TM+T*M. We define the interior product and Lie derivative so that the standard complex of TM+T*M becomes a g differential algebra, then we discuss its equivariant cohomology. We also study the equivariant cohomology for a subcomplex of a Leibniz complex. [less ▲]

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See detailEssays on Inequality, Public Policy, and Banking
Mavridis, Dimitrios UL

Doctoral thesis (2016)

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