Are Firms Withdrawing From Basic Research? An Analysis of Firm-level Publication Behaviour in Germany

in Scientometrics (2021), 126

Performance assessment of the relative gravimeter Scintrex CG-6

in Journal of Geodesy (2021), 95:116

The new-generation relative gravimeter Scintrex CG6 is put on the test bench: Its performance is compared to its predecessor, the Scintrex-CG5. A CG5 Scintrex and a CG6 Scintrex were both submitted to the ... [more ▼]

The new-generation relative gravimeter Scintrex CG6 is put on the test bench: Its performance is compared to its predecessor, the Scintrex-CG5. A CG5 Scintrex and a CG6 Scintrex were both submitted to the same rigorous tests, which have been developed in recent years to highlight some defects of the CG5. The results show that the CG6 always performs better than the CG5. For instance, the instrumental drift is 5 times smaller for the CG6 than for the CG5. In the tidal bands, the noise level of the CG6 is 3 times lower than of the one of the CG5. We confirmed the tilt susceptibility of the CG5 and found that the CG6 is barely affected by long duration tilts before taking measurements. Unlike the CG5, the CG6 measurements are not influenced by external temperature variations. Overall, the CG6 provides more precise and stable gravity measurements compared to the CG5. [less ▲]

Spinning Functional Fibers: An Interplay of Rheology, Miscibility & Crosslinking

Doctoral thesis (2021)

Wearable technology in general has increasingly gained interest in the last few decades and textile with incorporated functional component constitute one form of it. There are multiple ways to produce ... [more ▼]

Wearable technology in general has increasingly gained interest in the last few decades and textile with incorporated functional component constitute one form of it. There are multiple ways to produce polymer fibers on both laboratory and industrial scales, and one of them is core–sheath electrospinning, which is a powerful method for producing advanced composite fibers. Liquid crystals (LCs), are materials that readily exhibit optical response to fluctua- tions and change in their immediate environment. By incorporating LC within polymer fibers through electrospinning, it is possible to create responsive LC-polymer fiber mats. However, incorporating a functional core has proven challenging for certain combinations of materials. This thesis explores and addresses some of the concerns involved in the coaxial electrospinning of fibers incorporating LCs from several standpoints. Firstly, the effect of solvents on the electrospinning process was systematically studied. Fol- lowing this, an optimum viscosity with pure and mixed solvents for successful electrospinning was identified and uniform fibers with different solvent combinations was produced. Using the knowledge gained, core-sheath electrospinning with LC as the core was carried out. One of the key findings of this work, the identification of a suitable means to reduce the interfacial tension between the core and sheath fluid to prevent break up of the jet and produce uniformly filled fibers, while at the same time avoiding complete mixing between core and sheath. These findings can be applied to any combination of core and sheath materials and should appeal to a large community of researchers. Eventually, to achieve the durability of the LC-functionalized electrospun fiber mats for use in wearable technology, the sheath polymer of the fiber were crosslinked after spinning. The resultant crosslinked fibers were easily manipulated by hand and even fully immersed in water without dissolving and without losing their functional LC core. [less ▲]

Mendelian randomization study of smoking, alcohol, and coffee drinking in relation to Parkinso's disease

in Journal of Parkinson's Disease (2021)

Background:Previous studies showed that lifestyle behaviors (cigarette smoking, alcohol, coffee) are inversely associated with Parkinson’s disease (PD). The prodromal phase of PD raises the possibility ... [more ▼]

Background:Previous studies showed that lifestyle behaviors (cigarette smoking, alcohol, coffee) are inversely associated with Parkinson’s disease (PD). The prodromal phase of PD raises the possibility that these associations may be explained by reverse causation. Objective:To examine associations of lifestyle behaviors with PD using two-sample Mendelian randomisation (MR) and the potential for survival and incidence-prevalence biases. Methods:We used summary statistics from publicly available studies to estimate the association of genetic polymorphisms with lifestyle behaviors, and from Courage-PD (7,369 cases, 7,018 controls; European ancestry) to estimate the association of these variants with PD. We used the inverse-variance weighted method to compute odds ratios (ORIVW) of PD and 95%confidence intervals (CI). Significance was determined using a Bonferroni-corrected significance threshold (p = 0.017). Results:We found a significant inverse association between smoking initiation and PD (ORIVW per 1-SD increase in the prevalence of ever smoking = 0.74, 95%CI = 0.60–0.93, p = 0.009) without significant directional pleiotropy. Associations in participants ≤67 years old and cases with disease duration ≤7 years were of a similar size. No significant associations were observed for alcohol and coffee drinking. In reverse MR, genetic liability toward PD was not associated with smoking or coffee drinking but was positively associated with alcohol drinking. Conclusion:Our findings are in favor of an inverse association between smoking and PD that is not explained by reverse causation, confounding, and survival or incidence-prevalence biases. Genetic liability toward PD was positively associated with alcohol drinking. Conclusions on the association of alcohol and coffee drinking with PD are hampered by insufficient statistical power. [less ▲]

Exploring the Past in Public: Recent Public History Exchanges in Southern Luxembourg

Scientific Conference (2021, October 07)

A Distributed Unmanned Aerial Vehicles Traffic Management System

Doctoral thesis (2021)

The rapid adoption of Internet of Things (IoT) has encouraged the integration of new connected platforms such as Unmanned Aerial Vehicles (UAVs) to the ubiquitous network. UAVs promise a pragmatic ... [more ▼]

The rapid adoption of Internet of Things (IoT) has encouraged the integration of new connected platforms such as Unmanned Aerial Vehicles (UAVs) to the ubiquitous network. UAVs promise a pragmatic solution to the limitations of existing terrestrial IoT infrastructure as well as they bring new means of delivering services through a wide range of applications ranging from monitoring and surveillance to on-demand last-mile delivery and people transport. Owning to their potential, UAVs are expected to soon dominate the low-altitude airspace over populated cities. This introduces new research challenges such as the safe management of UAVs operation under high traffic demands. In response to this, industry proposed a handful of constructs for UAV Traffic Management (UTM), however due to their centralised approaches, they will inevitably face limitations in scalability and resilience with predicted traffic demands and advancement in UAV autonomy. In this context, the main objective of this work is to address the aforementioned problem by proposing a distributed UAV Traffic Management system (dUTM). This thesis, hence, investigates the validity of the above hypothesis by: (i) showing the performance insufficiency of centralised systems due to their inadequacy in efficiently optimising large UAV traffic, (ii) showing why a distributed system is favourable due to its characteristics of scalability and resilience, (iii) proposing a novel dUTM framework consisting of an airspace structure model, information exchange model and a traffic optimisation model that rely on distributed methods and approaches to intelligently handle highly dynamic and challenging traffic conditions. To this end, this manuscript contributes to scientific literature by proposing a novel way of structuring the uncontrolled, low-altitude airspace and introduces a model of the Class G airspace as a multi-weighted multilayer network of nodes and airways. Additionally the work presents a novel distributed multiobjective path planning algorithm incorporating a dynamic multi-criteria decision matrix allowing each UAV or agent to plan their path relying on local knowledge gained via digital stigmergy. The PhD thesis additionally contributes to existing state of the art by exploring the technical standardisation landscape and investigating synergies between research directions and standards developments, taking into consideration pressing inherit challenges of UAVs within IoT such as security, data protection and privacy. [less ▲]

Linking urban landscapes to ecosystem services and carbon flows: A European analysis.

Doctoral thesis (2021)

In the context of population growth and urbanisation, associated with an increase in the concentration of GHG (greenhouse gases) in the atmosphere, the impact of human activities on climate change is ever ... [more ▼]

In the context of population growth and urbanisation, associated with an increase in the concentration of GHG (greenhouse gases) in the atmosphere, the impact of human activities on climate change is ever increasing. Simultaneously, the pressure on natural ecosystems, especially in and around cities, is intensifying. Natural ecosystems associated with the urban forest (all elements of urban vegetation) can play an important role in mitigating climate change, especially in cities. In addition, they can contribute positively to the quality of life and wellbeing of urban dwellers. The dynamic of the services they provide, to Earth and mankind, vary between and within cities and need to be better understood. This thesis focusses on the impact of the spatial integration of the urban forest on the supply and demand of ecosystem services. The main objective is to provide insights into how urban forms and their inner characteristics are related to ecosystem services (ES) and to carbon dioxide (CO2) profiles. In particular, it analyses the level of integration of the urban forest present within the built up footprint and anthropogenic land, in order to derive the effect of their spatial distribution on 5 ES provided by the urban forest. The research is conducted at detailed spatial resolution for hundreds of Functional Urban Areas (FUAs) in Europe. It is structured as follows. We built an Urban Forest typology for Europe: 689 urban areas in 10 clusters and gathered in 4 groups (Forest cities, Herbaceous cities, Anthropogenic cities and Standard European cities). The typology reveals how nature is spatially integrated into urban structures. The metrics used in the typology reflect the potential supply and demand of 5 urban ES associated with the urban forest: micro climate regulation, macro climate regulation, air quality regulation, rainwater runoff regulation and physical and mental health. All cities are ranked according to an overall score. One of our main conclusions is that, given the same forest cover, a spatially integrated urban forest makes cities less sensitive to urban stressors. We then focus on a specific regulatory ES: macro climate regulation. The Urban Carbon Balance (UCB) model has been developed and allows the estimation of the urban carbon balance at a high spatial and temporal resolution for a large number of areas, using land used and emission data. The UCB model has been applied to 802 European urban areas. We downscaled anthropogenic CO2 emissions to a spatial resolution of 1 ha before applying a temporal decomposition of annual, monthly and finally daily emissions, following year-, sector- and country-specific guidelines. For a typical day of each month, we simulate 3 steady-state situations for the dispersion and sequestration of CO2 molecules. We find that the urban structure and the level of integration of the urban forest contribute positively to helping urban areas sequester their own emissions. [less ▲]

Digital Identities and Verifiable Credentials

in Business and Information Systems Engineering (2021), 63(5), 603-613

Public institutions and companies typically employ physical credentials (such as passports, social security cards, and employee badges) to identify individuals. Individuals can choose where to store their ... [more ▼]

Public institutions and companies typically employ physical credentials (such as passports, social security cards, and employee badges) to identify individuals. Individuals can choose where to store their physical credentials, and sometimes, they can decide to whom their credentials are disclosed. These familiar privileges inspired a new type of digital credential called a verifiable credential (VC). Similar to physical credentials, individuals can store their verifiable credentials in a so-called digital wallet on their mobile phone, on another edge device, or in the cloud, and they can use verifiable credentials for identification, authentication, and authorization. [less ▲]

Emergent Multilingual Children's Agency within Translanguaging Practices with Peers and Practitioners in Formal and Non-formal Early Childhood Education Settings in Luxembourg

Doctoral thesis (2021)

In our increasingly globalised, heterogenous and varied societies, scholars have called for multilingual pedagogies that build on this diversity as a resource and promote flexible language practices to ... [more ▼]

In our increasingly globalised, heterogenous and varied societies, scholars have called for multilingual pedagogies that build on this diversity as a resource and promote flexible language practices to facilitate children’s participation and language appropriation or learning. Nevertheless, the existing literature on young children’s own capacities to act in light of these innovative and inclusive pedagogies remains scarce, particularly in multilingual contexts involving more than two named languages. This thesis presents a longitudinal qualitative study of young emergent multilingual children’s agency within translanguaging practices when appropriating new language features in early childhood education in multilingual Luxembourg. Guided by a sociocultural framework and a translanguaging lens, the study investigates the ways in which emergent multilingual children engage in translanguaging practices and thereby practise different forms of agency in interaction with peers and practitioners. The data stems from eight focal children, aged three to five, in two formal and two non-formal early childhood education settings. The qualitative data was collected over eleven months in 2016 and 2017, combining observations, fieldnotes, and video-recordings, as well as informal discussions and semi-structured interviews with the practitioners. The data analysis consisted of analysing recurring patterns and differences in the children’s deployment of their entire semiotic repertoires, conducting a micro-analysis of the children’s interactions with peers and practitioners as well as triangulating the data and the methods. The results revealed that the focal children were particularly active when appropriating new language features and shaped the language practices of their peers and the practitioners. The children thereby practised agency on two levels. Firstly, they did not passively reproduce the practices and languaging of the adults, but instead creatively transformed and implemented the practitioners’ (trans)languaging activities, practices and interaction patterns in their peer culture. Secondly, they showed language-based agentic behaviour on a continuum from participatory to controlling behaviour, during interactions with both their peers and the practitioners. While the participatory agency consisted of showing creative language-based agentic behaviour under the control of the practitioners, the controlling agency went beyond mere participation and related to children taking choices in language use and actively shaping the language use of their peers and the practitioners. These findings may be particularly relevant to understanding the language practices and agency of young emergent multilingual children when they encounter new languages in early childhood education – in particular, as the children’s languaging and agency depended on the pedagogy and the practitioners’ language-supportive strategies. One important outcome of the study is the provision of recommendations for practitioners and policymakers wishing to capitalise on children’s rich and varied semiotic resources. The study is moreover of interest to researchers and students in the fields of early childhood education, language learning and multilingual education. [less ▲]

SEMKIS-DSL: a Domain-Specific Language for Specifying Neural Networks’ Key-Properties

Report (2021)

Neural networks are becoming increasingly part of today’s software systems. These neural networks are simplified models of the human brain that are mainly capable of learning from large datasets to ... [more ▼]

Neural networks are becoming increasingly part of today’s software systems. These neural networks are simplified models of the human brain that are mainly capable of learning from large datasets to compute some function based on recognized data. Engineering these datasets and these neural network-based software systems is a complicated and challenging task. Software engineers require methods and tools to engineer these datasets and neural networks for their customers and to satisfy their requirements. In general, they lack methods and tools to support the engineering of dataset and neural networks that satisfy the customer’s requirements. They follow traditional approaches consisting of time-consuming, imprecise and manual activities. Typically, these approaches are not supported by any tool that precisely analyse and specify the neural network’s recognition skills. In our previous work, we have introduced the notion of key-properties for describing the neural network’s recognition skills. In this paper, we define a domain-specific language to support our SEMKIS software engineering methodology for the dataset augmentation to improve network’s key-properties. We present the SEMKIS-DSL for the specification of the key-properties of a neural network. We illustrate the concepts of our DSL with a running example specifying a neural network for recognizing a digital meter counter state. This running example demonstrates a specification of the neural network’s key-properties using the SEMKIS-DSL and a successful improvement of the neural network’s recognition skills. [less ▲]